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Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginiy, May 5,1992 Prepared For: Eastern Shore of Virginia Ground Water Study Committee Accomac, Virginia 23301 too Prepared By: Horsley Witten Hegemann, Inc. Consultants in Water Resources and Land Planning 1680 E. Gude Drive Rockville, Maryland 20850 (301) 294-9895 This document was prepared under a United States Environmental Protection Agency 205(j) Water Quality Planning Grant for the Virginia State Water Control Board, and was funded, in part, by the Virginia Council on the Environment' s Coastal Resources Manage- ment Program through grant #NA90AA-H-CZ796 of the National TD Oceanic and Atmospheric Administration under the Coastal Zone 224 Management Act of 1972 as amended. N8 G76 1992 EASTERN SHORE OF VIRGINIA GROUND WATER STUDY COMMITTEE GROUND WATER SUPPLY PROTECTION AND MANAGEMENT P FOR THE EASTERN SHORE OF VIRGINI RESOLUTION OF ADOPTION BE IT RESOLVED that the Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia is hereby adopted by the Eastern Shore of Virginia Ground Water Study Committee. Duly adopted by the Eastern Shore of Virginia Ground Water Study Committee on May 5. 1992. certification: X. A a, I'-- (;V. C.D. Fleming @-f Chairman Eastern Shore of Virginia Ground Water Study Committee State of Virginia County of Accomack The foregoing instrument was acknowledged before me on this 5th day of May, 1992, by C.D. Fleming, Jr., Chairman of the Eastern Shore of Virginia Ground Water Study Committee. [email protected] my commission expires: ACKNOWLEDGEMENTS This report was prepared by Horsley Witten Hegemann, Inc. under contract with the Eastern Shore of Virginia Ground Water Study Committee. In researching and developing this document, it was necessary to collect information from many agencies and individuals. In particular, the following individuals provided special assistance in the production of the document: Jack Green and Jim McGowan, A-NPDC, Project Managers; Paul Berge, A-NPDC, Director; Virginia Newton, VA State Water Control Board; Robert Jackson, VA State Water Control Board; Gary Speiran, U.S. Geological Survey; Donna Richardson, U.S. Geological Survey; Rodney Lewis, Soil Conservation Service. Many other local, state and federal officials contributed information or conducted reviews of drafts, and their efforts are greatly appreciated. HWH also wishes to recognize our two subcontractors Dr. Lewis Waters who conducted the land use analysis and Dr. Daniel Morrissey who assisted in the hydrogeologic investigation. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia TABLE OF CONTENTS PAGE: 1 INTRODUCTION Overview 1-1 Executive Summary 1-3 Purpose of Project 1-6 2. WATER RESOURCES ON THE EASTERN SHORE OF VIRGINIA Topography and Soils 2-1 Surface Water 2-2 Hydrologic Units 2-4 Farm Ponds 2-6 Tidal Wetlands 2-6 Ground Water 2-6 Introduction 2-6 Hydrogeology of the Eastern Shore Aquifers 2-10 Summary of Existing Technical Reports 2-10 Flow and Recharge Patterns on the Eastern Shore 2-11 Water Use 2-14 Crop Irrigation 2-14 Public and Industrial Water Use 2-18 Private Water Use 2-23 Poultry 2-23 3. CONTAMINATION THREATS Waste water disposal 3-2 Public Sewage Systems 3-2 On-site Septic Systems 3-2 VPDES Permits and Mass Drainfields 3-4 Agriculture 3-4 Fertilizers 3-5 Pesticides 3-10 Animal Waste and Animal Carcasses 3-12 Industrial /Commercial Land Uses 3-12 Underground Storage Tanks 3-12 Toxic Chemicals 3-13 Solid Waste Disposal 3-15 Septage Disposal 3-18 4. EXISTING LAND USE Purpose 4-1 Overall Status of Land Use Controls 4-1 Existing Patterns of Land Use 4-2 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia Land Use and Open Space Requirements for Water 4-3 and Sewer E)dsting Land Use in Accornack County 4-4 Agriculture and Agricultural Districts 4-4 Housing and Residential Districts 4-4 Industry, Business, and Industrial/Commercial 4-7 Districts Existing,Zoning and Land Use in Northampton County 4-7 Agriculture and Agricultural Districts 4-7 Housing and Residential Districts 4-8 Industry, Business, and Industrial/Commercial 4-8 Districts Other Uses 4-9 Land Use Controls and Effects on Ground Water 4-10 Subdivision of Land 4-12 Subdivisions in Accomack County 4-13 Subdivisions in Northampton County 4-14 The Chesapeake Bay Program on the Eastern Shore of Virginia 4-14 Introduction 4-14 Basic Approach 4-14 Implications for Ground Water Protection 4-15 Summary of Land Use on the Eastern Shore 4-17 5. DELINEATION OF GROUND WATER SUPPLY MANAGEMENT AREAS Introduction 5-1 Selection of Aquifer Protection Criteria 5-1 Zone 1 5-1 Zone 2 5-2 Zone 3 5-3 Physical Description of Each Wellhead Protection Area 5-6 Wellhead Protection Area A - Chincoteague Area 5-6 Wellhead Protection Area B - Holly Farms (Tyson Foods) Area 5-6 Wellhead Protection Area C - Perdue Area 5-7 Wellhead Protection Area D - Exmore Area 5-7 Wellhead Protection Area E - Cape Charles Area 5-8 6. WATER BUDGET/ BALANCE Recharge to the Columbia Aquifer 6-1 Recharge to the Yorktown-Eastover Aquifer 6-1 Salt Water Intrusion 6-3 7. BUILDOUT/DEVELOPABLE LOT ANALYSIS Developable Lot/Land Use Analysis 7-1 Methods 7-1 Buildout Assumptions 7-2 Buildout Analysis Results 7-4 Buildout Analysis Summary 7-4 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8. NITROGEN LOADING Introduction 8-1 Nitrogen as a Contan-dnant 8-1 Sources of Nitrogen 8-3 Sewage 8-3 Fertilizers 8-4 Animal Waste 8-4 Lawn Fertilizers 8-5 Landfills 8-6 Septage Lagoons 8-6 Pavement and Roof Runoff 8-6 Estimation of Paved Area/Roof Area 8-7 Business/ Industrial/ Institutional 8-7 Precipitation 8-7 Nitrogen Loading Analysis 8-7 Nitrogen Modelling Results 8-8 Existing Water Quality Results 8-11 Virginia Department of Health, Public Water 8-11 System Inventory State Water Control Board/EPA STORET Database 8-11 Virginia Department of Health, Eastern Shore District 8-13 USGS Water Quality Sampling 8-13 Nitrogen Loading Analysis Under Future Buildout Conditions 8-15 9. CASE STUDIES AND THEIR APPLICABILITY TO THE EASTERN SHORE OF VIRGINIA Agricultural Practices 9-1 Lancaster County, Pennsylvania: Fertilizer Effects on 9-1 Water Quality Jefferson County, Wisconsin: Controlling Disposal of 9-3 Livestock Wastes Delmarva Peninsula: Composting Dead Chickens 9-4 On-site Waste Disposal 9-6 Ontario, Canada: Nitrogen Plumes from Septic Systems 9-6 Falmouth, Massachusetts: Performance Standards 9-7 Within Zones of Contribution Long Island, New York: Restrictions Within Recharge Zones 9-8 Gloucester, Massachusetts: Siting of Septic Systems 9-19 Locations Throughout The U.S. Constructed Wetlands, Alternative to Conventional Wastewater Treatment 9-10 Surface Water Management 9-11 Chesapeake Bay Area, Maryland: Stormwater Pollutant 9-11 Reduction Buzzards Bay, Massachusetts: Stormwater Treatment System 9-13 Chesapeake Bay Area, Maryland: Vegetated Buffer Zones 9-14 Hazardous Materials Handling and Storage 9-15 Portland, Oregon: Land Use Controls Within Wellhead 9-15 Protection Area Dayton, Ohio: Overlay District For Aquifer Recharge Area 9-16 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia Palm Beach County, Florida: Ground Water Protection 9-17 Through Zoning Ordinance Comprehensive Monitoring Programs 9-18 State of Rhode Island: Salt-pond Watchers, Watershed Watch 9-18 10. CONCLUSIONS OF THE REPORT 11. RECOMMENDATIONS Recommendations for Water Quality and Quantity Protection 11-1 Recommendations for Water Quantity Management 11-3 General Recommendations 11-5 Continued Research and Investigation 11-5 APPENDIX A - WATER QUALM A-1 APPENDIX B - POPULATION B-1 APPENDIX C - LAWS AND REGULATIONS APPLICABLE TO STUDY C-1 APPENDIX D - EASTERN SHORE OF VIRGINIA GROUND WATER STUDY COMMITTEE D-1 APPENDIX E - HYDROGEOLOGIC CALCULATIONS E-1 APPENDIX F - BUILDOUT NITROGEN LOADING CALCULATIONS F-1 APPENDIX G - REFERENCES AND RESOURCES G-1 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia V LIST OF TABLES PACE: Table 2-1 Towns and Villages Located by Hydrologic Units 2-4 Table 2-2 Agricultural Water Use by County 2-16 Table 2-3 Irrigation Estimates, 1987-1989 2-17 Table 2-4 Accomack-Northampton Planning District Irrigation With 2-18 Source Detail Table 2-5 Summary of Permitted Public and Industrial Water Use 2-18 Table 2-6 Major Municipal Withdrawals 2-18 Table 2-7 Average Annual Water Withdrawals, Eastern Shore, Virginia 2-19 1985-1990 Table 2-8 Permitted Withdrawal Rates for Inactive Facilities 2-22 Table 3-1 Public Sewage Facilities 3-2 Table 3-2 Residential Disposal of Septic Wastes 3-3 Table 3-3 Facilities With Discharge Permits, Eastern Shore, Virginia 3-6 Table 3-4 Facilities Using Mass Drainfields, Eastern Shore, Virginia 3-8 Table 3-5 Nitrogen Fertilizer Requirements, Eastern Shore, Virginia 3-11 Table 3-6 Underground Storage Tanks by Wellhead Protection Area 3-14 Table 3-7 EPA List of Active Generators and Transfer Storage 3-16 Disposal Facilities, Accomack and Northampton Counties Table 3-8 Virginia Toxic Substances Chemical Inventory, Accomack and 3-16 Northampton Counties Table 4-1 Existing Land Use - Accomack and Northampton 4-3 Table 4-2 Land Use Category by Zoning District, Eastern Shore of Virginia 4-5 Table 4-3 Zoning Lot Sizes and Open Space 4-6 Table 4-4 Analysis of Land Use Effects on Ground Water Supplies 4-10 Table 4-5 Subdivision Development in Accon-tack County, 1972-1990 4-13 Table 4-6 Subdivision Development in Northampton County, 1974-1990 4-14 Table 6-1 Salt Water Upconing Modelling Results 6-6 Table 7-1 Minimum Lot Sizes Used in Buildout Analysis 7-2 Table 7-2 Buildout Summary 7-4 Table 7-3 Calculations for Buildout Within Incorporated Towns, 7-5 Accomack County Table 7-4 Calculations for Buildout Within Urban Development Areas, 7-5 Northampton County Table 7-5 Developable Lot Analysis, Accomack and Northampton 7-7 Counties Table 8-1 Total Nitrogen Concentrations in Septic System Effluent 8-3 Table 8-2 Leaching Rates for Fertilizers Applied to Turf Areas 8-5 Table 8-3 Total Nitrogen Concentrations in Road Runoff 8-6 Table 8-4 Nitrogen Loading Values 8-8 Table 8-5 Nitrogen Loading Calculations: Accomack Existing 8-9 Table 8-6 Nitrogen Loading Calculations: Northampton Existing 8-10 Table 8-7 Virginia Department of Health Public Water Test Results 8-11 Table 8-8 Nitrate-nitrogen Levels Above 5 mg/I in STORET (EPA) 8-12 File, Accomack and Northampton Counties Table 8-9 Eastern Shore Health District Shallow Well Monitoring Results 8-13 Table 8-10 USGS Nitrogen Sampling, 8-14 Table 8-11 Nitrogen Concentration By Wellhead Protection Area 8-15 Table 8-12 Nitrogen Loading Under Future Buildout Conditions In Spine of Wellhead Protection Area per Source 8-16 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia v i Table 9-1 Sampling Results in Two Pennsylvania Rivers 9-1 Table 9-2 Pollutant Reduction Goals by Land Use Categories, State of 9-12 Maryland Table A-1 Regulated Contaminants A-1 Table B-1 1990 U.S. Census Population Counts, Accomack-Northampton B-1 Planning District Table B-2 Historical and Projected Population Figures B-1 Table E-1 Water Balance for the Eastern Shore of Virginia E-1 Table E-2 Thornthwaite Method for Evapotranspiration (ET) Calculations E-2 Table E-3 Water Balance for the Eastern Shore of Virginia, Recharge to E-3 Yorktown-Eastover (Confined) Aquifer Table E-4 Recharge Calculations for the Yorktown-Eastover Aquifer E-4 Table F-1 WPA (A) Future Nitrogen Loading Calculation F-1 Table F-2 WPA (A) Future Nitrogen Loading Calculation -Developable Soils Only F-2 Table F-3 WPA (B) Future Nitrogen Loading Calculation F-3 Table F-4 WPA (B) Future Nitrogen Loading Calculation -Developable Soils Only F-4 Table F-5 WPA (C) Future Nitrogen Loading Calculation F-5 Table F-6 WPA (D) Future Nitrogen Loading Calculation F-6 Table F-7 WPA (E) Future Nitrogen Loading Calculation F-7 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia vi LIST OF FIGURES PAGE: Figure 1-1 Locus Map of Eastern Shore of Virginia 1-2 Figure 2-1 Soils Map 2-3 Figure 2-2 Map of Hydrologic Units 2-5 Figure 2-3 Locations of Farm Ponds 2-7 Figure 2-4 Hydrologic Cycle 2-8 Figure 2-5 Generalized East/West Cross-section of Ground Water 2-9 Flow in the Eastern Shore of Virginia Figure 2-6 Conceptual Hydrogeologic Model of Non-Pumping Ground 2-12 Water Conditions on the Eastern Shore of Virginia Figure 2-7 Conceptual Hydrogeologic Model of the Eastern Shore With 2-14 a Pumping Well at the Edge of the Peninsula Screened in the Yorktown-Eastover Aquifer Figure 2-8 Water Use by Category 2-15 Figure 2-9 Yearly Precipitation Amounts, Painter, Virginia, 1985-1990 2-16 Figure 2-10 Industrial Water Withdrawals vs. Permitted Amounts 2-24 Figure 2-11 Public Water Withdrawals vs. Permitted Amounts 2-24 Figure 2-12 Public and Industrial Water Withdrawals vs. Pern-dtted 2-25 Figure 2-13 Public and Industrial Water Withdrawals by Month, 1990 2-25 Figure 3-1 Typical Sources of Contan-driation to Ground Water 3-1 Figure 3-2 Septic System and Ground Water Contamination 3-3 Figure 3-4 Underground Storage Tanks Broken Down By Age 3-13 Figure 3-5 Locations of Landfill Sites and Septage Lagoons 3-17 Figure 5-1 Eastern Shore Potentiometric Map: Permitted Pumping 5-4 Figure 5-2 Map of Wellhead Protection Areas 5-5 Figure 6-1 Salt Water Intrusion 6-4 Figure 6-2 Upward Vertical Migration of Salt Water 6-5 Figure 7-1 Example of Future Land Use Within Spine Recharge Area 7-3 Figure 8-1 Nitrogen Transformations 8-2 Figure 9-1 Scheme of Simple Poultry Composter 9-5 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia vii I I I I INTRODUC-nON I 1 1 1 1 1 1 1 1 1 1 1 1 1 I I SEMON 1: INTRODUMON OVERVIEW Ground water resource protection and management on the Eastern Shore of Virginia (see Figure 1-1 for locus map) requires the involvement and cooperation of many levels of government as well as a commitment from the private sector. The private sector plays an important role because ground water withdrawals for operations such as industrial processing and agricultural irrigation greatly exceed public water supply needs. If development progresses in the Counties of Accomack and Northampton, however, the ratio of public to private water use is expected to rise. The majority of ground water is withdrawn from deeper confined aquifers found on the Eastern Shore. The water quality in these aquifers is generally very good. Ground water in the unconfined, shallow aquifer is of poorer quality than that found in deeper aquifers, and is used primarily for individual private wells and for irrigation. Septic systems, agriculture, and commercial and industrial development have all been identified as potential sources contributing contan-driants to the shallow aquifer, primarily in the form of nitrogen. The current low density of development found on the Eastern Shore allows for the establishment of land use controls and cooperative efforts to protect water quality by private and public institutions. A major concern on the Eastern Shore is overpurnping of water from the deeper confined aquifers. Although the volume of water stored in the aquifers and the recharge that infiltrates naturally over the land surface has been calculated within a range of uncertainty of a factor of two to support the current rates of water withdrawal, for the Eastern Shore as a whole, further salt water intrusion may occur. In fact, Virginia State Water Control Board data from selected test wells indicate decreases in water levels and increases in salinity adjacent to the largest industrial withdrawal wells. Moreover, if the existing facilities increase their pumping rates to the maximum volumes allowed in their permits, several areas of the Eastern Shore are predicted to experience increasing problems of well interference, salt water intrusion, and a deterioration of water quality. Several management scenarios are available to ensure that there is adequate water in the future to meet anticipated demands and to protect both the shallow and deep aquifer systems from a deterioration in water quality. This study summarizes available information on water withdrawals, land use threats, and current control mechanisms on the Eastern Shore. Recommendations are proposed to develop a comprehensive ground water protection and supply management plan which will maintain an adequate supply of water and sustain high water quality for the future needs of the region. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia Figure 1-1: Locus Map of the Eastern Shore of Virginia PENNSYLVANIA -- - - - - - - - - - - - -f MARYLAND DELAWARE L- - - - - - MARYLAND C3 30 scaiW (miles) Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 1-2 EXECUTIVE SUMMARY The Eastern Shore of Virginia is an 80 mile long peninsula that comprises about 696 square miles of area, located at the southern tip of the Delmarva Peninsula and within the Eastern Coastal Plain Province. The Eastern Shore is bounded on all sides by water, except to the north which is bordered by the Maryland mainland. The Atlantic Ocean is to the east and the Chesapeake Bay to the west and south. Ground water is the only source of supply for domestic, industrial, and agricultural water use. A total population of approximately 47,000 use this ground water. Most of the production wells are set to draw water at various levels in the sen-d-confined aquifer (called the Yorktown-Eastover) found at about 300 feet below mean sea level. The water table aquifer (called the Columbia) is used extensively for agricultural irrigation and private wells. Accomack and Northampton Counties are the administrative units that govern the Eastern Shore and control all land use activities in conjunction with nineteen small towns. The Accomack- Northampton Planning District Commission has commissioned the development of a Ground Water Management and Supply Protection Plan that will provide a comprehensive and practical series of options, alternatives and specific actions to promote compatibility between the Eastern Shore's water resources and the counties land use plans. In 1976 the Virginia State Water Control Board designated the Eastern Shore of Virginia a "Ground Water Management Area". The Eastern Shore was the second area in Virginia to be declared a ground water management area. This declaration was based on the findings that: � Ground water level declines have been observed in two sections of Accomack County; � Interference between wells has been observed in the same two sections of Accomack County; � Some evidence of localized ground water contamination has been observed in the water table aquifer of Accomack County but not in the confined aquifers; � Even though the ground water supplies in Accomack County are not overdrawn and are not expected to be in the near future, it should be recognized that they may overdraw in some areas in the future if water withdrawals are not distributed throughout the region. Further, saltwater intrusion has not been observed to date but may occur in the future if heavy ground water withdrawals are concentrated in any one area. The major impact of the Ground Water Management Area designation is that all water users that withdraw in excess of 10,000 gallons per day (gpd) are subject to a state permit process. Ten major existing industrial and municipal withdrawals became grandfathered and did not have to subn-dt extensive permit applications. Currently, there are no regulations controlling agricultural water use, except for the reporting of water use on an annual basis. The aquifers on the Eastern Shore are strongly influenced by the lithology. Annual precipitation of 42 inches per year provides the recharge to the aquifers. The upper aquifer, called the Columbia Aquifer, is unconfined, and is roughly 80 to 100 feet thick. This aquifer is used primarily for private on-site domestic wells, and agricultural irrigation. Approximately 2 million gallons per day are withdrawn by private on-site wells for domestic use. Some portion of the 8.7 million gallons per day withdrawn for irrigation comes from the Columbia aquifer. Anywhere from 12 - 24 inches per year of precipitation recharges the Columbia aquifer on the Eastern Shore of Virginia. At an average recharge rate of 17 inches per year, approximately 324 million gallons per day recharge the Columbia aquifer. Most of this water flows from the middle Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 1-3 of the peninsula and discharges to the Chesapeake Bay and the Atlantic Ocean. A small percentage contributes to the recharge of the deeper confined aquifer. Water quality in the Columbia aquifer is threatened by the many land uses that discharge, leach or dispose of contaminants to the ground water. Nitrate-nitrogen is the primary contaminant of concern to the Columbia aquifer. Sources include: septic systems; agricultural fertilizers; manure storage and animal disposal; septage lagoons; and landfills. In addition, pesticides and underground storage tanks are also threats. The average nitrogen concentration in the ground water was calculated to be 2.0 milligrams per liter. The national drinking water standard for nitrogen is 10 milligrams per liter. On average, the shallow ground water quality is considered very good however, those areas located down gradient from major nitrogen users or disposers will experience much higher nitrogen concentrations. The next water bearing zone is the Yorktown-Eastover Formation, a confined aquifer consisting of coarse shelly sands found in three layers separated by clay confining units. This aquifer can range in depth from 80 to 800 below the land surface, though most wells are pumping from layers between 150 and 300 feet deep. The clay confining layers that separate the Columbia aquifer from the Yorktown-Eastover serve to protect the aquifer from many of the water quality threats. They also act to impede the amount and rate of recharge to the aquifer. It is estimated that only 1.2 inches of precipitation recharge the Yorktown-Eastover aquifer. Based upon the ground water modelling studies conducted, approximately 11 million gallons per day is recharge to the Yorktown-Eastover. However, it should be noted that this recharge value is based on average conditions across the entire Eastern Shore, and depending upon specific site conditions can vary by a factor of two in either direction. Additional study is necessary to better define the recharge rate to the Yorktown- Eastover aquifer. Industrial withdrawals and public water supply wells are exclusively screened in the Yorktown- Eastover aquifer, while wells used for agriculture and private household use are withdraw from the upper aquifer. Currently 4.5 million gallons per day are withdrawn from this aquifer for industrial use and public water supply, Permits from the Virginia State Water Control Board would allow withdrawals of up to 15.6 n-dllion gallon per day from this aquifer. If this were to occur, problems of well interferences and salt water intrusion, already observed near the largest industrial water users, will be greatly enhanced. Local planning and elected officials on the Eastern Shore have been concerned for a number of years about the quality and availability of ground water. The State Water Control Board of Virginia has conducted several studies and developed a network of ground water monitoring wells on the Eastern Shore to document problems. In addition, through cooperative studies, the U.S. Geological Survey has developed reports and modelled the hydrogeology. The results of these investigations all agree that the major issues are: � Agriculture, water quality and quantity; � Animal wastes; � Development impacts, septic systems, underground tanks; � Well interference, industrial and public water supply wells, � Salt water intrusion; � Adequate water supply, future demands, all uses. Each of these activities/concems have an impact on water use and quality for either the upper aquifer, the lower aquifer or both. Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 1-4 A land use buildout study was conducted to assess the maximum potential for development within the spine recharge area. The findings show that under current zoning, the number of single-family dwelling units that could potentially be developed within the spine recharge area is greater than the total number of existing units county-wide. This has serious implications for future wastewater disposal,water supply and agricultural use. Buildout conditions were modelled for impacts on ground water quality due to nitrogen contan-dnation. The area with the most likely impacts will be in WPA (B) in the vicinity of Holly Farms (Tysons Foods). The Ground Water Supply Protection and Management Plan For the Eastern Shore of Virginia provides a review of each of these threats including land use impacts under future buildout conditions. In addition, the recharge areas to the major pumping wells have been delineated. An aquifer recharge zone was mapped based upon hydrogeologic information that suggests that the source of recharge to the confined aquifer is located along the spine of the peninsula. Based upon the analyses conducted and the review of existing information, the study proposes the following actions: Recommendations for Water Quality Protection � Pursue water conservation measures with major industrial users. � Create an overlay protection zoning district to protect the spine recharge area to the Yorktown- Eastover aquifer; � Restrict the siting of new mass drainfields in the spine recharge area; Review and revise county zoning and subdivision regulations; � Require the registration of currently unregulated underground storage tanks; � Incorporate ground water protection requirements into site plan review; � Develop a private well ordinance to control the siting and construction of new wells; � Support the implementation of agricultural nutrient management plans; e Implement the provisions of the Chesapeake Bay Program. Recommendations for Water Quantity Management � Revise State Ground Water Act and Regulations to allow for reevaluation of existing permits; � Develop an Eastern Shore Water Management District to manage water withdrawals; 9 Control the siting and development of new water supply wells to prevent well interference and reduce the threat of salt water intrusion; � Continue the accurate reporting of agricultural water withdrawals, by well location and depth. Continue the consideration of mandatory permitting of agricultural withdrawals after review of reporting data. Protect open space and undeveloped land in the spine recharge area. General Recommendations 9 Implement a land use/water quality data base; * Develop a public education program on ground water. Continued Research and Investigation 0 Investigate the nature of recharge to the Yorktown-Eastover aquifer; - Research dilute salt water issues; - Conduct additional hydrogeologic studies to better define the geology; e Evaluate pesticide use on the Eastern Shore; Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 1-5 � Support additional agricultural nutrient management research; � Revise the nitrogen model used in the study over time. The Eastern Shore of Virginia is situated over a very valuable ground water resource that is the sole source of water supply to the inhabitants and is also necessary for both industrial and agricultural use. Protection of the water quality and quantity will require the implementation of many actions designed to maintain water quality, prevent against over use of the aquifer and provide for the future needs to accommodate growth on the Eastern Shore. PURPOSE OF PROJECr This project prepared by Horsley Witten Hegemann, Inc. (HWH), was guided and funded by the Eastern Shore of Virginia Ground Water Study Committee. The committee was formed for the purpose of assisting local governments and residents of the Eastern Shore to understand, protect and manage their ground water resources. In addition to serving as an informational and educational resource, the Committee initiates special studies concerning the protection and management of the Eastern Shore. This Ground Water Resources Protection and Management Plan is one of several ways in which the Committee intends to carry out its goals. The Committee consists of 2 members from each county's Board of Supervisors, one citizen appointee by each Board of Supervisors, the County Adn-dnistrator from each county, and the Executive Director of the Accomack-Northampton Planning District Commission. This report responds to three aspects of the Committee's purpose: 1. The report provides management information by identifying the quantity of ground water available for use, and explaining the potential for de-watering of the ground water aquifers, salt water intrusion, and contamination. 2. The report provides recommendations regarding ground water quality protection; identification and protection of ground water recharge areas; nitrate-nitrogen loading to the water table; land application of pesticides; and hazardous material storage. 3. The report, combined with public forums, maps, and background information on the hydrogeologic cycle and ground water conditions on the Eastern Shore, advises the public as to their role in protecting ground water and identification of threats to water quality and quantity. An additional goal of this project is to improve coordination among those municipalities, state and local governments, and private sectors responsible for the protection, management, and research regarding the Eastern Shore ground water supply. Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 1-6 I I I I I WATER RESOURCES ON THE EASTERN SHORE OF VIRGINIA 1 2 1 1 1 1 I I I I I I I I I SECTION 2: WATER RESOURCES ON THE EASTERN SHORE Ground water is the only source of drinking water on the Eastern Shore, and is therefore considered the most important water resource. However, an understanding of the water system as a whole is necessary to understand future land use and development decisions designed to protect water supplies. This section provides an overview of the water resources on the Eastern Shore of Virginia. Soil types and the geology which influence water quality and quantity are also discussed. TOPOGRAPHY AND SOILS Accomack and Northampton Counties lie in the Coastal Plain Province of Virginia. The soils of the two counties are predominantly comprised of sand, clay, and shell fragments, deposited during the Miocene Era Tennema and Newton, 1982). The resulting land is one of the most productive in the entire Atlantic Coastal Plain. The region is generally flat, with a central plateau. Maximum elevation of the plateau is 45 feet above mean sea level, and the slope rarely exceeds two percent. From the central northeast- southwest trending divide, the land gradually slopes toward the Chesapeake Bay and Atlantic Ocean shorelines. Soil characteristics greatly influence the activities which may take place on the land above them, and thus play a significant role in planning and development. For example, layout and grading of roadways, excavations for foundations of new buildings, and the operation of septic tanks are all affected by soil suitability. Factors such as permeability, depth, natural fertility, and drainage are important when considering agricultural potential and future development sites. Soil drainage is particularly important on the Eastern Shore where the primary method of disposing domestic waste water is by septic systems. If the soil is not suited for wastewater disposal, waste water must be transported to an area of suitable soil, or else be treated in a central treatment facility. According to the Soil Survey of Northampton County (Soil Conservation Service,1989 and 1990) and the Accomack County Comprehensive Plan (1989), there are five major soil associations on the Eastern Shore of Virginia. A soil association is an area of land made up of two or more geographically associated soils which occur in a similar pattern. The following paragraphs summarize the Soil Conservation Service's characteristics of these soil associations: Bojac-Munden-Molena This association makes up 48% of the two counties. It is nearly level to steep, moderately well drained to somewhat excessively drained, loamy and sandy soils; on broad flats, side slopes, and escarpments. Of the five associations, this one is the best for development. However, there are some development limitations due to erosion, wetness, and shallowness of sorts. Munden soil, in particular, is considered excellent for development. Septic tank suitability is moderate, generally limited by poor drainage. Ninimo-Munden-Dragston Covering 15% of the two counties, this association is nearly level, moderately well drained to poorly drained, consisting of loamy soils found on broad flats and depressions. The association is not always suitable for development. Septic tank suitability is severe due to a seasonal high water table and poor drainage. Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 2-1 Chincoteague-Magotha Covering 28% of the two counties, this association is nearly level, very poorly drained to poorly drained, silty and loamy soils, found in tidal marshes. Not suitable for development, the soils are best utilized as wetland wildlife habitat and as spawning grounds for shellfish and finfish. This association is frequently flooded, has a moderate natural fertility, and is well suited for salt- tolerant plants. Nimmo-Arapahoe Located in the northwest portion of Accomack County only, this association covers 5% of the two counties. It is level, poorly drained, and suitable for development and agriculture if properly drained. The Soil Conservation Service on the Eastern Shore, however, considers the area where these soils lie to be undevelopable. Fisherman-Beaches-Camocca Covering 4% of the two counties, this association is nearly level to steep, moderately well drained and poorly drained, sandy soils and beaches, found on flats and low dunes and depressions. Because of the location in wetland resource areas, the soil association is not suitable for development. Figure 2-1 displays the locations of these soils. The soil types located on the mainland of the peninsula (except Nimmo-Arapahoe) are categorized as prime farmland. This category constitutes 68% of the land in the counties of Northampton and Accomack. Water bearing capacity of these soils is moderate, and the natural fertility is low. Typically these soils are acidic. They are well suited to cultivated crops, soybeans, small grains, vegetables, and ornamentals (SCS, 1989). In general, the two counties contain soils that are less than ideal for proper septic system functioning, generally due to a seasonal high water table. The Accomack County Comprehensive Plan maintains that the Bojac-Munden-Molena soil associations are well drained and suitable for development and agricultural lands. These soil types constitute 44% of Northampton County's land, and 52% of Accomack County, and thus are the most prevalent soils. It should be noted that the entire town of Chincoteague, Accomack County's most developed magisterial district, is underlain by the Fisherman-Beaches-Camocca formation, which is described as unsuitable for development because of poor drainage and susceptibility to a seasonal high water table, flooding, and instability (SCS, 1989). Chincoteague receives its water from several wells on the mainland near the NASA Wallops facility, and so does not need to be as concerned about ground water contan-tination problems within the town. However, any residents using private wells should be wary of the quality of their water, given the number of septic systems in this poorly suited soil. SURFACE WATER Surface water includes ponds, streams, creeks, bays, and lagoons. The Eastern Shore is unique compared to mainland Virginia in that there are no major streams or other surface water supplies which can serve as a source of drinking water. This point underscores the importance of protecting the ground water supply, because alternative sources for drinking water do not exist. Surface water systems are, however, interconnected with ground water. The water table on the Eastern Shore of Virginia is shallow, and surface water and ground water play an important interactive role. Although not used for drinking water, surface water systems are important for shellfish, finfish, and other wildlife.on the Eastern Shore. These animals benefit the general economy of the area: the finfish industry grossed over one million dollars in 1986, and the sale of shellfish in 1986 was Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 2-2 OCEAN ATLANTIC AL .. . ....... CHESAPEAKE FISHERMAN-BEACHES-CAMOCCA CHINCOTEAGUE-MAGOTHA BOJAC-MUNDEN-MOLENA NIMMO-MUNDEN-DRAGSTON NIMMO-ARAPAHOE I LOW 0 22.000 33.000 scale (1001) 2-3 valued at over nine million dollars, according to the Accomack County Comprehensive Plan (1989). The Virginia State Water Control Board and the Virginia Department of Health Shellfish Sanitation monitor the overall quality of surface water to protect public health in recreational contact and to insure that the waters can sustain aquatic life. As a result of flat topography and well-drained soils, the peninsula has no large fresh water lakes or waterways. Instead, there are several creeks which, in the lower reaches, are tidal estuaries fed by narrow branches. The Chesapeake Bay side of the peninsula receives the majority of surface runoff, where the creeks are more pronounced. On the Atlantic Ocean side, the barrier islands create a bay and lagoon system, and this side has smaller creeks. In Accomack County, 12 creeks feed into the ocean side, and 19 creeks ebb and flow into the Bay. In Northampton County, there are 21 watersheds, with 15 on the Bay side. Currently, a water quality monitoring project of tidal creeks in Northampton County is underway. It is a collaborative effort between the Citizens for a Better Eastern Shore (CBES), The University of Virginia, the Virginia Coast Reserve of the Nature Conservancy, the Eastern Shore Working Waterman's Association, and the Virginia Student Environmental Health Project (STEHP). The project will provide baseline information on the status of aquatic habitats and surface water resources of Northampton County. All data derived in the project will eventually be accessible to the general public, and a report completed by the end of 1991 will be submitted to the local board of supervisors and the planning district commission. Recommended actions are expected to result from the presentation of the report. Hydrologic Units The USDA Soil Conservation Service has grouped together the 52 watersheds on the Eastern Shore Peninsula to form fourteen (14) hydrologic units. These are essentially larger management units which have common drainage areas. Figure 2-2 indicates the boundaries of the hydrologic units. The following is a breakdown according to county and village. The units beginning with the letter "C" are on the west (Bay) side of the peninsula, and the "D" units are on the east (Ocean) side. Lower numbers are farther south than higher numbers. Table 2-1: Towns and Villages Located by Hydrologic Units Accomack Coun!y: C04: [Belle Haven, Bloxom, Craddockville, Davis Wharf, Middlesex, half of Painter, and half of Pungoteaguel C05: [Harborton, half of Melfa, and half of Pungoteaguel C06: [Onancock and half of Onleyl C07: [Greenbush, Hallwood, Horsey, Leemont, Mappsville, Mears, Nelsonia, Parksley, Sanford, Saxis, Tasley, and half of Withams] C08: [New Church, Oak Hall, and half of Withams] D03: [Keller, half of Painter, Quinby, and half of Wachapreaguel D04: [Accomac, Centerville, Locustville, half of Melfa, half of Onley, and half of Wachapreaguel D05: [Temperanceville and half of Wallops Island] D06: [Atlantic, Chincoteague, Greenbackville, Horntown, Half of Wallops Island, Wallops Station, and Wattsvillel Northa=ton Coun1y: C01: [Dalbys] C02: [Cape Charles, Cheriton, and Chesapeake] Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 2-4 C08 town Rue D06 .in F" I ISLAND Poco"00CE NATIONAL chi"" ;I SIASHOIK C07 soumose"Asy Bay mamom 'r D05. w"ge I an Od n Mesconos pas C06 P" Cos ley D 0 4 Mel pr crad Voila sinter ,In C04 lie adl Patramom I svillo h le 0 Quit D 0 3 Hoe Island J" r 3&y C03 hipon J. 044 machiponso Inift cl- C 0 2 kin c-" D02 Cobb 34 UtLw cow WNW CAP* C S91- ouch say C01-p i DO 1 FIGURE 2-2 T CIOM MAP OF cam HYDROLOGIC FfSKERMAMS ISLAND 'N w R UNITS 110 -wVv-LrM-ll E 2-5 C03: (Bridgetown, Churchneck, half of Eastville, and Machipongol C04: [Bayford, Birdsnest, half of Exmore, Jamesville, half of Nassawadox, and Silver Beach] DOI: [Capeville, Seaview, and Townsend) D02: [Half of the Town of Eastville] D03: [Half of Exmore, half of Nassawadox, Weirwood, and Willis Wharf] Faim Ponds In the two counties, over 325 excavated "farm ponds" supply about 85% of the water used for irrigation (Cooperative Extension Agents Jim Belote, Fred Diem, personal communication, 1991). It is unknown how many of these ponds are used as storage areas for water that has been pumped from wells. Farm pond locations, as supplied by the Accomack-Northampton Planning District Comn-dssion, are shown in Figure 2-3. Some of the locations in Figure 2-3 have multiple ponds. While it is unclear which of these ponds intersect the water table, the use of surface water for irrigation, rather than well water, reduces the stress on the use of the deeper ground water supply However, farm pond construction by creek damming may destroy valuable wetland habitat and negatively effect downstream productivity (Paul Gapcynski, William & Mary, Virginia Institute of Marine Science [VIMSL Eastern Shore Natural Resources Symposium speech 4/11/91). Two studies conducted by VIMS have shown no negative effects on downstream productivity (letter from J. Rodney Lewis, SCS, 7/8/91). Ditches have also been constructed on the Eastern Shore to connect creeks in order to increase drainage (Fennema and Newton, 1982). This has the effect of increasing surface water runoff rates. Additionally, several dams have been built in estuaries below and at the head of tide water to supply irrigation water. Tidal Wetlands Both Accomack and Northampton Counties contain numerous tidal wetlands. Wetlands are some of the most ecologically productive systems in the world, and are sensitive to land development and use. Tidal wetlands serve as water filters, mitigate the impact of storms, and provide habitat for a variety of wildlife, aquatic life, and plants. Accomack County has 70,000 acres of vegetated tidal wetlands, divided between salt marshes along the Atlantic Ocean shoreline, and brackish marshes on the Chesapeake Bay shoreline. Accomack County also contains extensive non-vegetated intertidal flats on the ocean side. Non-vegetated tidal wetlands are located between mean high water and mean low water and are adjacent to tidal marshes. Tidal wetlands in Northampton County are located on both the ocean and bay sides, and total 35,000 acres. GROUND WATER Introduction The Eastern Shore of Virginia depends entirely upon ground water supplies for its municipal and industrial water needs. Virtually no streams or rivers exist on the peninsula, nor are there surface water lakes or reservoirs of appreciable size. Ground water serves the water supply needs of the Eastern Shore today, and will continue to do so in the foreseeable future. As a result of this dependence on ground water, protection of the resource, both in terms of water quantity and water quality, takes on an added importance. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 2-6 ATLANTIC OCEAN C3 oo 4fo%o 00 00 0 0 % 09 1 0 000 0 *,to 0 0 9 o oo 0 0 0 0 000 A%.. 0* 0 % 0 00 0 9 4i- 00 0 @c CHESAPEAKE 9 APPROXIMATE LOCATION OF FIGURE 2-3 FARM PONDS LOCATIONS OF FARM PONDS 11.000 0 22.000 33.ODO -1 scale (loot) 1HI 2-7 Ground water on the Eastern Shore is derived from precipitation falling on the land surface of the two counties. Some of that water is intercepted by vegetation and is transpired or evaporated directly back to the atmosphere. A portion runs off as overland flow while some penetrates the soil and is used (transpired) by plants. Part of the precipitation moves through the unsaturated zone and recharges the unconfined (Columbia) aquifer. Figure 2-4 below illustrates the hydrologic cycle. Most water in the Columbia aquifer flows laterally from the center of the peninsula, contributing to the baseflow of small streams or is held in temporary storage in ponds before discharging to the Atlantic Ocean or Chesapeake Bay. A much smaller portion of water in the unconfined aquifer continues its vertical inigration through the clays and silts that separate the Columbia from the underlying Yorktown-Eastover aquifer, recharging the confined aquifer system. See Figure 2-5. Tangier Island, a small island that is part of Accomack County and is located ten miles off the coast of Virginia in the Chesapeake Bay, also obtains drinking water from ground water sources. The island has a separate hydrogeologic system from the mainland, and was not studied in detail in this report. Figure 2-L- Hydrologic Cycle A? rr ORMUM MW -RV-APCRAT-ION MANSPIPATWN NPLTMTM DOW. - OF @Nc WATUt %9W Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 2-8 Figure 2-5 Generalized EastfWest Cross Section GENERALIZED EAST / WEST CROSS-SECTION OF GROUND WATER FLOW ON THE EASTERN SHORE OF VIRGINIA WEST ICentral Plateau I EAST Chesapeake PRECIPITATION Atlantic Bay + + + + + + + + + + ocean see Water Table Piezometric Level . . .............. .. ....... ... ...... ..... .. ............ ....... . ... ...... ... . . . . . . . . . . . . ..... . . . . . . . . . . . . . . . . . ...... . . . . . . . . . . . . . ........... ..... . ........ it a Salt 3round Ground Water Water ED Fresh water Aquifer 7 Fresh Water Aquitard Piezo" Ground Water Supply Protection and Management Plan for the EaVern Shore of Virginia 2-9 Hydrogeology of the Eastern Shore Aquifers The most important geologic formations with regard to ground water supply are the Columbia and the Yorktown-Eastover. The Columbia was deposited during the Pleistocene (10,000 to 15,000 years before present). The sediments are primarily sands with interfingering clay and silt beds. From a water budget calculation, it was determined that between 12 and 26 inches per year recharges the unconfined system (see Appendix R Much of that recharge flows laterally through the Columbia aquifer and discharges to the Chesapeake Bay, streams and estuaries as well as the ocean. Some water passes through the 20- to 100-foot thick confining unit of silty clay below the Columbia and enters the other aquifer of importance to the Eastern Shore, the Yorktown-Eastover Formation. The Yorktown-Eastover was deposited during the Miocene era, between 5 and 23 million years before present. This deposit consists of three layers of aquifer separated by confining units. Recharge to the confined system from the unconfined Columbia aquifer at steady state, pre-pumping conditions is estimated from analytical modelling at approximately 0.10 feet per year (See Appendix E). The Upper, Middle, and Lower aquifers are comprised primarily of fine to coarse shelly sands. Thickness of the permeable sections vary from as little as 10 feet to as thick as 120 feet. The aquifer deposits possess moderate permeability with transn-dssivities ranging from less than 1,000 gpd/ft (130 ft2/day) to as high as 40,000 gpd/ft (5300 ft2/day) (F&ME, 1990; Fennema and Newton, 1982). Transn-dssivity is the measurement of how much water moves through the aquifer, and is measured by multiplying the permeability of the aquifer by its thickness. The three aquifers are separated by confining units composed of clays and silts of much lower permeability. These units range from less than 10 feet to as much as 70 feet in thickness. In addition to the Columbia and Yorktown-Eastover aquifers three major paleochannels (coarse sediments deposited in stream channels that cut through the older sedimentary deposits) have been identified on the Eastern Shore (Colman and others, 1990), created by the downcutting of streams during several periods of low sea level during the Pleistocene. Two of these channels cross the main body of the Eastern Shore peninsula, at Exmore and at Eastville. The third major channel crosses south of the peninsula near Cape Charles and Fisherman's Island. The streams that formed the channels cut into the Yorktown-Eastover Formation as much as 200 feet, depositing sands and gravels in the central portion of the channel overlying those sediments with less permeable sands, silts and clays (Colman and others, 1990). The width of the paleochannels is less certain but is mapped in Colman and others (1990) as roughly 1-2.5 miles wide. Summary of Existing Technical Reports Available technical reports, including journal articles, consultant's reports, State Water Control Board and U.S. Geologic Survey publications were reviewed for this project to better understand the previous investigations of the Eastern Shore. The technical literature can be divided into three principal categories. The first include those reports presenting basic geologic and hydrologic data. Such reports are fundamentally compilations of data with descriptive commentary and include many of the U.S. Geological Survey papers and Virginia Division of Mineral Resources reports. For example, Teifke (1973) provides a thorough exan-dnation of the geology of the entire coastal plain of Virginia, including the Eastern Shore. The publication is a very useful one with its detailed rock type descriptions from borehole logging as well as its discussion of depositional environments for the formations that make up the region. Sinnott and Tibbitts (1968) offer a comprehensive overview of the geology and hydrology of the Eastern Shore in particular, along with well and water quality data. Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 2-10 The second type of report comes from independent researchers and consultants. These reports (e.g., F&ME, 1990) focus on local aspects of Eastern Shore hydrogeology. Their main utility in terms of the objectives of a ground water protection program lies in the raw data they provide from drilling logs and water quality analyses along with data from test pumping that can be used to obtain aquifer coefficients. The third type of report is more interpretive in form, applying the basic data to the issues involving the hydrogeology of the Eastern Shore. Many of the Virginia State Water Control Board Planning Bulletins fall into this category. A series of Planning Bulletins, No. 45 (1975), No. 309 (1977) and No. 332 (1982), have charted the efforts of the Board to detail the hydrogeologic conditions of the Eastern Shore in both a conceptual and quantitative manner, along with discussions of how that understanding can contribute to solutions to ground water problems. Bulletin No. 45 offers a comprehensive view of hydrogeologic conditions on the Eastern Shore as they existed almost twenty years ago. That report identified the following key issues: (1) ground water level declines in the confined Yorktown-Eastover aquifer, (2) well interference, (3) salt water intrusion, and (4) ground water contamination that continue to trouble the area. Bulletin No. 309 (Ball, 1977) acted on a specific recommendation of Bulletin No. 45 to construct a two-dimensional numerical flow model of the confined aquifer of the Eastern Shore to apply a more quantitative approach to the understanding and management of the resource. That trend towards a quantified view of the hydrogeology was continued in Bulletin No. 332 (Fennema and Newton, 1982) which augmented Bulletin No. 45's basic information, incorporating borehole geophysical data, water quality information from established research stations and test pumping results. That report presented a series of extremely useful cross-sectional correlations along and transverse to the axis of the peninsula. A forthcoming report from the U.S. Geological Survey (Richardson, in press) continues the move towards quantification of the hydrogeologic conditions of the Eastern Shore with a three-dimensional saltwater/freshwater interface numerical model of the area. Flow and Recharge Patterns on the Eastem Shore A conceptual understanding of the flow patterns and locations of the recharge areas on the peninsula is crucial to protecting those areas of most importance to the water supply of Accomack and Northampton counties. That conceptual model must take a three-dimensional approach which incorporates vertical components of flow to account adequately for the hydrogeologic conditions on the Eastern Shore. The key element of that model with respect to protecting the long term quality and quantity of the ground water on the Eastern Shore is the role played by the central spine of the peninsula. The center portion functions as the primary recharge source for the heavily used confined Yorktown-Eastover aquifer, and the center portion's protection is of utmost importance to the continued viability of the confined aquifer as a source of water. The overall flow and recharge patterns can perhaps best be illustrated through the use of several models developed during the course of this project. The models are cross-sectional views of the peninsula used to observe where ground water is recharged and discharged by the various aquifer systems and the nature of flow within and between aquifers and confining units. The models used were generated numerically by McDonald-Morrissey Associates in conjunction with HWH. United States Geological Survey MODFLOW code was used to model input parameters of aquifer and confining unit thickness, permeability, recharge rates, etc., consistent with those found in the literature for the Eastern Shore. Several steady state model runs were performed to gain a better conceptual view of the ground water flowpaths and recharge areas under different pumping scenarios. While numerical in form, the runs of the model serve best as aids in developing a correct conceptual notion of ground water conditions on the Eastern Shore. Figure 2-6 describes the flow system of ground water under pre-pumping conditions on the peninsula. This figure is for conceptual purposes only and does not represent a quantitative estimate of the recharge area. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 2-11 FIGURE 2-6. Conceptual Hydrogeologic Model of Non-Pumping Ground Water Conditions on the Eastern Shore of Virginia Chesapeake Columbia Confining Upper Yorktown-Eastover Upper Yorktown-Eastover Atlantic Bay Aquifer Unit Aquifer Confining Unit Ocean XK -K . . . . . . . . . . . tall Water Water .......... ......................... . .......... ........... . . . ................... .......... ........... ............... ..... ... .. ........................... ......... ............. -........... ......... . . .... ........ .................. . .. ...... ... ............................... .. ......... ... :.. :.. .. 1.*1 , *:: ... .. ... ... . ..... .... ....... . . ......... . I . . . . . . . . . . . . . . ......... ................. ......... . ...................... .... .. --------------- .............................. ............. . ............................................... ....... .. . ........... ........ ....... ........ FAddle Yorktown-Eastover Midde Yorktown-Eastover Lower Yorktown-Eastover Aquifer Confining Unit Aquifer F] Recharge Pathway Flow to Columbia Aquifer F__] Recharge Pathway Flow to Upper Yorktown-Eastover Aquifer Lo Recharge Pathway Flow to Middle Yorktown-Eastover Aquifer MM Recharge Pathway Flow to Lower Yorktown-Eastover Aquifer 2-12 Precipitation falling on or across the peninsula recharges the unconfined Columbia aquifer. Much of that water moves laterally within the unconfined unit and discharges to the ocean or Chesapeake Bay. A portion continues vertically downward through the confining unit until it reaches the Yorktown-Eastover aquifer. The model shows that the deepest portion of the Yorktown-Eastover aquifer (the lower Yorktown-Eastover) receives its recharge from a very narrow strip along the central spine of the peninsula. Once in the lower Yorktown-Eastover aquifer, water moves laterally and then upward through the confining layers, finally to discharge into the Atlantic Ocean or Chesapeake Bay. The Middle and Upper Yorktown-Eastover aquifers receive their recharge in a similar manner, but from a broader area on either side of the peninsula, reflecting both the higher permeabilities of those units as well as their relative stratigraphic positions. That is, there are fewer confining units to go through before the water reaches the aquifers. The model demonstrates the fact that recharge to the confined Yorktown-Eastover aquifer under pre-pumping conditions occurs at the center of the peninsula. Precipitation falling on the sides of the peninsula moves laterally through the Columbia aquifer, not vertically downward through the confining layer. Much of the water recharged to the Columbia, therefore, discharges to the Atlantic Ocean and the Chesapeake Bay, not the Yorktown-Eastover aquifer. Figure 2-7 conceptually illustrates a scenario of steady state pumping conditions, detailing the pathlines of ground water movement to a pumping well located at the edge of the peninsula. In a somewhat non-intuitive manner, this cross-sectional numerical model shows that the surface area of land immediately around the well contributes nothing to its yield. Precipitation falling on the Eastern Shore in the immediate vicinity of the well will recharge the Columbia aquifer, but the majority of flow in those areas does not pass through the confining layer to recharge the Yorktown- Eastover aquifer and contribute to the yield of the well. In this cross-sectional model, recharge from precipitation to the Columbia aquifer around the wellhead will discharge to the ocean. The recharge source of a water supply on the side of the peninsula is primarily derived from the central area of the land, albeit skewed towards the direction of the well to some degree. In this model, the deepest section of the Lower Yorktown-Eastover aquifer actually obtains its water from beyond the mddpoint of the peninsula in this pumping scenario. As the distance between a pumping well and the center of the peninsula spine increases, a well will derive its water supply from more than one area. Part of its recharge will continue to come from the center of the peninsula, but part will come from other areas of the Columbia, induced by the gradients created by pumping. A detailed quantification of precisely where these areas n-dght be was not possible under the scope of this project. With a properly constructed and calibrated three dimensional model, particle tracking routines could be used on the final head distribution to determine to a much higher degree of precision the origin of the water discharged by a well. This would offer a superior quantification of the proportion of water derived from downward leakage through the confining layer near the well relative to water derived from recharge at the center of the peninsula. Unfortunately, such a three-dimensional flow model does not yet exist for the Eastern Shore, and its construction is beyond the scope of this project. The numerical cross-sectional model was created for conceptualizing purposes, and it serves only to emphasize the importance of the center of the peninsula to the quantity and quality of water available to the confined aquifer system. While other areas of the Columbia undoubtedly contribute to the water supply of wells screened in the Yorktown-Eastover aquifer, even for wells located at the sides of the Eastern Shore, the key recharge area is the center of the land mass. The numerical modelling which generated the conceptual hydrogeologic model for the Eastern Shore illustrates a concept vital to the development of wellhead and aquifer protection strategies on the Eastern Shore. Simply stated, the most important area to protect in order to assure continued good quality and large quantities of ground water throughout the Eastern Shore is the center of the Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 2-13 Figure 2-7 Conceptual Hydrogeologic Model of the Eastern Shore of Virginia with a Pumping Well at the Edge of the Peninsula Screened in the Yorktown-Eastover Aquifer Pumping Well at Edge of Atlantic ChesaPake Peninsula Recharge Area Center of Ocean Bay Q for Well Peninsula Columbia Aquifer . ............ ............... Confining Unit tit wale r Upper Yorktown-Eastover Aquifer water. . ........... Upper Yorktown-Eastover Confining Unit i .......... . ............. .. .. ....... . ........... .... .................... .......... ................ ..... . ....... ........ ............. ... .. ........ ................... .............. ....... ...... . ............ ...............*.............. .... ...... . .......... .. -Eastover Aquifer .............. X. ............... %%% ......... Middle Yorktown .............%. ............... .... ..... . . .................................... ............... ............ ...... . ............................. ....... . .............. ....................I. ...... ............ Middle Yox t ................................. wn-Eastover Confining Uni i ................. ..... ... .... ....... ... ............. - ---------- ------------------- ............ Lower Yorktown-Eastover Aquifer L F-I Recharge Pathway Flow to Upper Yorktown-Eastover Aquifer Recharge Pathway Flow to Middle Yorktown-Eastover Aquifer Recharge Pathway Flow to Lower Yorktown-Eastover Aquifer 2-14 peninsula. Under pumping conditions, the important role of the central portion of the peninsula in maintaining adequate aquifer protection is even more apparent. A protection scheme that does not emphasize the center portion of the Eastern Shore, taking into consideration the three-dimensional character of the flow paths, will prove rrdsleading and ineffective. WATER USE A water budget for the Eastern Shore of Virginia has been established by comparing known water withdrawals to the rate of recharge to the aquifer. This budget will help identify water quality and salt water intrusion problems as well as predict the overall future of the ground water supply of the Eastern Shore of Virginia. This section identifies major water users, which include public, industrial, private, crop irrigation, and poultry categories. In Section 6, the water budget is analyzed with respect to the hydrogeologic conditions of the peninsula. 20 Figure 2-8: Water Use by Category 18 - 16 ... Agriculture 14-- ..... .. ...... ....- ..... . ....... Industrial 12--./ Private 10- --------------- Public 8- 6 4- 2 0 1986 1987 1988 1989 1990 1991 Years Crop Irrigation Agriculture is the most water-intensive land use on the Eastern Shore. The State Water Control Board estimates the gallons of water used for irrigation based upon a voluntary survey which is completed by farmers. As of 1991, this survey will no longer be voluntary, and it is expected that the estimations will become more comprehensive if not more accurate. The following (Table 2-2) is a summary of agricultural water use (in millions of gallons per day - MGD) according to the Virginia State Water Control Board. Table 2-3 provides greater detail of this chart. Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 2-15 Table 2-2: Agriculture Water Use by County (MGD) 12az im im IM Accomack 6.04 6.46 6.86 2.56 NQW=MOM 5.17 3D8 1.94 2.62 Crop irrigation involves a seasonal use of water, but the figures have been annualized to give an average daily withdrawal over the course of each year. Total irrigation did decrease from 1987 to 1989, and this coincides with an increase in rainfall, as shown in Figure 2-9. Figure 2-9: Yearly Precipitation Fainter, Virginia, 1985-1990 60.0- 575- 55.0- Precipitation 52.5- Average -%.0- N, 47.5- 45.0- % 42.5- 0 M ------------ 40.0- Y 37.5- -Boor 32.5-- 30.0 1 1 1 ' I 1984 1985 1986 1987 1988 1989 1990 1991 Years Source: National Oceanic and Atmospheric Administration Earlier in this section, it was estimated that surface water farm ponds supply approximately 85% of the irrigating water. The State Water Control Board includes source information in its survey. Table 2-4 summarizes the findings. According to the state survey, ground water contributes much more than the 15% that is estimated by the Extension Service, and a small amount of public water is also used. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 2-16 V Table 2-3: Irrigation Estimates, 1987-1990 Reported % of Reported % of water Year Geographic Numbers Reporting Acreage acreage Water applied Annualized Ave. appl. Rainfall (in.) Area Farms Nurseries Irrigated in VA Applied (MG) in VA Rate (mgd) (in.) AEr.-Sept. 1Z - 1987 Accomack 72 12 9588 21.9 2204 22-2 6.037 8.5 12.61 Northampton 30 3 7122 162 1888 19.1 5.173 9.8 Virginia 520 47 43866 100 9916 100 27.168 8.3 ;3 1988 Accomack 118 18 10397 26 2357 25.7 6.457 8.3 22.43 Northampton 42 8 5760 14.4 1125 12.3 3.083 7.2 Virginia 430 75 39945 100 9181 100 25.152 83 1324 3.628 1989 Accomack 43 11 10182 413 2502 48 6.855 9 30.27 Northampton 41 4 5563 22.5 707 13.6 1.938 4.7 Virginia 278 46 24669 100 5211 100 14.278 7.8 1990 Accomack 31 4210 935 2.56 8.18 27.21 Northampton, 24 4829 956 2.62 7.29 M Ln Source: Virginia State Water Control Board - VA Crop Irrigation Water Use Reports for 1987-1989,1990 figures unpublished from the SWCB. Rainfall data from NOAA, not SWCB. ft Table 2-4: Accomack-Northampton Planning District Irrigation With Source Detail 1987 1988 1989 Acres Millions Acres Millions Acres Millions Water Source Irrigated Gaons Irrigated Gallons Irrigated Gallons Surface Water 4,666 1,552 5,361 1,072 6,420 1,136 Ground Water 8,802 2,198 9,318 2,334 8,141 1,956 Mixed Source 2,510 172 1,479 77 1,082 116 Public Supply 664 171 0 0 104 1 TOW 16,621 092 16,157 3A82 15,747 3,210 Source: Virginia State Water Control Board Public and Industrial Water Use Nonagricultural facilities which withdraw in excess of 300,000 gallons of ground water per month are required to obtain a withdrawal pern-dt from the Virginia State Water Control Board (SWCB). The effect of the pern-dt is to put a limit on the amount each facility can withdraw. The pern-titted amount allotted to each system may include a grandfathered amount plus an amount based upon historical use. Generally these wells are dug into the deep aquifer. The following is a sun-unary of withdrawals in millions of gallons per day. Table 2-7 lists facilities which have permits and their withdrawals from 1985 to 1990. Some listed in the database as currently withdrawing water do not have a permitted rate of withdrawal, according to the SWCB. Those facilities without a pern-dt have a "+" symbol in the "Permitted" column of Table 2-7 . Table 2-5: Summary of Permitted Public and Industrial Water Use (MGD) im 12H JM JM JM JM Permitted (1991) Public 1.3 1.3 1.4 1.4 1.5 1.2 4.5 Industrial 3.4 3.1 3.2 3.1 3.4 3.3 11.1 Total 4.7 4.4 4.6 4.5 4.9 4.5 15.6 Six incorporated towns have central water supplies. Together they withdrew approximately 1.03 millions of gallons a day in 1990. Table 2-6 lists the withdrawal amounts for each municipal supply. Table 2-6: Major Municipal Withdrawals Town 1990 Withdrawal Permitted Amount (MGD) (MGD) Cape Charles 0.134 0.261 Chincoteague 0.447 1.340 Eastville 0.060 (1989) + Exmore 0.166 0.320 Onancock 0.161 0.234 Parksley 0.060 0.100 Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 2-18 Table 2-7: Average Annual Water Withdrawals, Eastern Shore, VA 1985-1990 C) Well No. ITOWN/FACILITY LATITUDE LONGITUDE 1985 1986 1987 1988 1989 1990 PERMITTED* PUBLIC SUPPLIES Accornack County 100-OOD41 Accomack Co. Nursing Home 374528 7,53721 0.0160 0.0150 0.0145 0.0145 0.0166 0.0181 0.0294 100-00039 Captain's Cove #1 380010 752534 0.0190 0.0180 0.0189 0.0117 0.0112 0.0081 + 100-00031 Captain's Cove #2 375949 752500 0.0062 0.0043 0.0044 Captain's Cove #5 (out of service) 375911 757528 100-00265 Chincoteague #3 375626 752725 0.0270 0.0400 0.0751 0.0827 0.0280 0 Chincoteague #3A same meter as #5 375626 752725 0.0084 Chincoteague #3B 375626 752725 0.0084 0.0552 110 [email protected] #3C 375626 752725 0.0084 0.04% 100-00028 Chincoteague 04 375633 752721 0.1850 0.1840 0.1795 0.1572 0.1711 0.1392 134 100-00032 Chincoteague 15 375626 752723 0.0390 0.0410 0.0314 0.0126 0.0056 0.004 100-00320 Chincoteague #6 375641 752714 0.1590 0.1340 0.1752 0.1729 0.1713 0.1349 100-00493 Chincoteague GA 375550 7527.54 0.0660 0.0790 0.0510 0.0354 0.0549 0.0351 100-00494 Chincoteague #7B 375557 752749 0.0354 0.0435 0.0286 100-00495 Chincoteague VC (closed - high iron) 375604 752742 0.0000 NAs7k-Waflops Island #3 375144 753034 0.0138 0.0057 100-00568 NASA-Wallops Island 375035 752545 0.0099 0.0209 NASA-WaUops Island Well #4 375128 753045 0.0048 0.0098 100-00002 Onancock 374233 754430 0.0782 O.OB71 0.0971 0.2388 100-00004 Onancock 374233 754432 0.0990 0.0960 0.1186 0.0052 0.0044 100-00036 Onancock 374234 754430 0.0469 0.0435 0.0486 100-00037 Onancock 374259 754453 O.OU75 0.0049 0.0054 100-00038 Onancock 374259 754454 0.0076 0.0098 0.0101 100-Ml Parksley #I all wells, same 374703 753901 0.0816 0.0728 0.0738 0.0575 0.1 100-00013 Parksley #2 meter 374703 753902 100-00014 Parksley #3 (not in service since 1984) 374704 753859 100-00439 VA-Landing Campground 372844 754742 0.0090 0.0133 0.0111 0.0088 O.OU79 + 100-00207 Wallops Island Main Base 375626 752807 0.1720 02050 0.11% 0.1420 0.1994 0.1009 0.263 Wallops Island Station 375135 753034 0.0710 0.0150 0.0247 0.0220 0.0099 0.127 tn Northamp n County ;a- 04 165-00042 America House Motor I meter for 2 wells 370816 755808 0.0140 0.0110 0.0116 0.0089 0.0076 0.0209 165-00260 America House Motor Inn # 1 370815 755810 0.0063 0.0076 0.0032 165-OW28 Cape Charles (Does not exist??) 371605 760017 1 0.0000 0 0.261 165-00048 Cape Charles 01 371605 760022 0.1570 0.2050 1 0.1852 0.1100 0.0766 0.0105 165-00123 Cape Charles #2 371607 760011 0.0509 0.15M 0.1231 Cherrystone I loliday Trav-L-Park 371719 760043 0.0600 0.06 1165-00030 Eastvffle #3 372117 755640 0.0000 0.0000 U06 1165-00031 Eastvifle 372116 755640 0.0450 0.0490 0.0447 0.0000 0.0000 [iC5-70-0036 EastvWe 372117 1 755640 0.0000 O.aw MMMOMMM ==Now== Table 2-7: Average Annual Water Withdrawals, Eastern Shore, VA 1985-1990 C) Well No. TOWN/FACILITY LATITUDE LONGITUDE 1985 1986 1987 1988 1989 1 1990 PERMITTED* 165-00038 Eastville (backup) 372106 755620 0.0000 0.0000 ;3 165-00014 Exrnore #2 373230 754917 0.0670 0.1030 0.0675 0.0570 0.0509 0.1111 0.32 165-00015 Exrno- #1 373230 754917 0.0410 0.0630 0.0773 0.0673 0.0667 0.055 165-00026 Eastville #2 (#5) 372117 7556,40 0.0591 0.0580 + 165-00001 Northampton-Accomack Hospital 372835 755145 0.0190 0.0120 0.0000 0.0748 02749 0.1039 0.1 165-00025 Northampton-Accomack Hospital 372835 755145 0.0490 0.058U 0.0782 0.0003 0.0024 0.0015 3Z Brown & Root 371500 760000 1.1 :9 ViCanio Residential Communities 371314 760009 028 1z 165-00259 ViCanio Chesapeake . 371333 760006 0.022 165-00054 Peaceful Beach, Kirkwood #1 373114 75-566D 0,229 165-00055 Peaceful Beach Campground 02 373114 755660 rl-65-00063 Peaceful Beach Campground #3 373114 75-%60 Peaceful Beach, Kirkwood 3731W 755630 0.0000 1 0.0000 1 0.0000_1 0.0000 1 0.0000 1 Public Supply Total 1.2430 1.2640 1.2594 1.2414 1.4148 1.1140 4.4617 INDUSTRIAL SUPPLIES ;2 Accornack County t-i M, t!' O-Q IOD-00006 Byrd Foods #1 374537 754004 0.0370 0.0060 0.0031 0.0027 0.0071 0.0101 0.6 C) 100-00054 Byrd Packing Co. 374531 754011 100-00367 Byrd Foods #3 374534 754007 100-00368 Byrd Packing Co. 374536 754003 IOD-00369 Byrd Packing CO. 374536 754003 IOD-00009 Holly Famis #4 375318 753344 02045 0.22% 0.1901 0.2512 1.8 100-OMIO Holly Farnis #3 375311 753339 0.1996 0.1972 0.1692 0.1179 100-00011 Holly Farnis #2 375304 753332 0.2412 0.1785 0.1863 0.1598 IOD-00012 Holly Farnis #1 375256 753324 0.6870 0.7170 0.1619 0.1009 0.0924 0.1061 M IOD-001% Holly Farnis 05 375330 753355 0.0838 0.1153 0.1953 0.1581 M - tn 100-00566 Holly Farnis #6 375257 753321 0.0175 0.0364 0.026 !1 100-00258 New Church Energy Assoc. 375833 753218 0.0970 0.1570 0.0759 0.1435 0.1991 0.1767 0.336 ;3 100-00365 New Church Energy Assoc. 375838 753218 0.0300 0.1099 0.0361 011775 100-0(X)20 Perdue Foods #4A 374403 753937 0.1060 O.WM 0.0221 0.01% 0.0618 0.224 2-6379 100-00026 Perdue Foods #2 374419 753910 0.4640 0.4710 0.4468 0.4001 0-9M 0.4974 100-00029 Perdue Foods #3 374429 753922 0.4450 0.4100 0.4336 0.4328 0-3956 0.41T6 100-00030 Perdue Productions 11 374408 753859 0.2510 0-2140 0.2038 0.1929 0.2280 0.244 IOD-00195 Perdue Foods #4 374421 753937 0.2310 0.1970 0.1622 0.0928 0.1429 0.1157 100-00531 Perdue, Inc. #5 374425 753933 0-3217 0-3273 03763 0.3683 100-00843 Eastern Shore Seafood (pumpstart2/91) 375122 753336 1 1 0-3 1100-00237 Shore Seafood # 1 375513 754348 0.3230 0.1990 0000 UR 0.0734 0.0941 + IIOD-00238 IShore Seafood 92 375512 754348 0.0000 0.0243 0.0941 Shore Seafood #3 375512 754348 0.0734 0.0941 Table 2-7: Average Annual Water Withdrawals, Eastern Shore, VA 1985-1990 C) Well No. TOWN/FACILITY LATITUDE LONGITUDE 1985 1986 1987 1988 1989 1 1990 PERMITTED* 0.1005 0.094 Shore Seafood #4 375512 754348 1 100-00229 Taylor Packing Co. 375232 753528 0.2070 0.1030 0.0680 0.0630 0.0440 0.5488 -100-00346 Taylor Packing Co. # 1 375233 753528 100-00347 Taylor Packing Co. #2 375233 753528 IOD-M8 Taylor Packing Co. #3 375233 753528 Northamp n County 165-00108 American Original Foo same meter 123 373045 754828 0.1190 0.1140 0.0000 0.1155 1 0.0617 0.45 165-00116 American Original Foods Obs. #123 373046 754825 0.0000 165-00117 American Orig. Foods Obs. #122 373046 754925 0.1562 165-00110 Bayshore Concrete # 1 371544 760119 0.(Tl% 0.0820 0.0727 0.0382 0.0209 0.0166 0.125 165-00111 Bayshore Concrete #3 371542 760124 0.0069 0.0141 0.0151 165-00142 Bayshore Concrete Prod. #2 371539 760114 0.0251 0.0197 0.0178 -165-00141 Bayshore Concrete 371539 760114 0.0054 0.0019 0.004 165-00045 C&D Seafood #2 371711 755524 0.0610 0.0460 0.0380 0.0286 0.0260 0.0297 0.152 165-00064 C&D Seafood #1 165-00018 Cus Enterprises 372150 755572 0.441 ;1 165-00019 Custis Enterprises 372150 755522 165-00005 Exmore Foods #7 373203 754917 2.002 165-00029 ExmoTe Foods #8 373160 754917 165-00039 Exmore Foods #9 373210 754913 165-00047 KMC Foods (clustered wells) 371746 755728 0.0033 1.6 165-00023 KMC Foods #4 (Labor Camp) 371746 755728 0.2390 0.1860 0.2748 0.2156 0.0161 165-00024 KMC Foods #5 371731 755730 1 165-00105 KMC Foods Plant Well 371732 755736 1165-00158 KMC Foods Inc. 371726 755729 :31 0.0341 1 0.15 Sea Watch International (HAS) 372219 755530 1 0.0660 0.0430 0.0335 JJW383 1 0.0389 Industrial Total 3.4120 3.0520 3.1573 3.0641 3.4331 3.4296 11.1427 GRAND TOTAL 4.6550 4.3160 4.4167 4.3055 4.8479 4.5436 15.6044 tn a, Q Source: VA Water Control Board Records 1985-1990; Virginia Newton, SWCB geologist Permitted Grandfathered rights + Permitted withdrawals 03. ;I Tangier Island supplies water for its population of 659 by means of 5 private water systems. These wells are not used for industrial purposes, only by residential and commercial facilities. According to the Eastern Shore Water Supply Plan (1988), the five wells were interconnected in 1987, and a storage tank was built in the case of emergency. Many pipes to the wells are old and leak, and it is difficult to determine flow from these wells since they are not metered. It was estimated in 1988 that the water demand for the town was .065 MGD. It is unknown how many wells exist on the island; the State says 11 and a well driller claims there are 14 wells Since Tangier Island is separate from the aquifer system on the mainland, and the water is withdrawn from a much greater depth (approximately 1,000 feet deep),this study did not focus in detail on the ground water situation on the island. Five permitted water withdrawal facilities are currently inactive. Their permitted amounts total just over 4 million gallons per day. Table 2-8 lists those inactive facilities and their permitted withdrawal rates. Table 2-8: Permitted Withdrawal Rates for Inactive Facilities Facility Permitted Amount NGD) Exrnore Foods 2.002 Custis Enterprises 0.441 Peaceful Beach, Kirkwood 0.229 DiCanio 0.302 Brown & Root 1.100 TOTAL 4.074 In addition, there are numerous schools, hotels, restaurants, small industries, trailer parks, churches, and n-dgrant labor camps that have private wells. Populations of community, non- community, and non-transient non-community facilities were obtained from the Virginia Department of Health. Water use by category was estimated using wastewater flow rates from Laak (1986), assuming that eighty percent of water use becomes wastewater (see page 8-3). Calculations show that these facilities use 140,000 gallons per day. From the Eastern Shore Department of Health, it was determined that a maximum of 3,058 people can occupy the area's migrant labor camps. Because these camps become the worker's residence during the duration of the season, average water use per person is estimated at 55 gallons per person per day. Therefore, the estimation of total labor camp water use is 168,000 gallons per day. Conservatively, if the labor camps were all in operation at the same time, the total water consumption from all these private facilities (schools, churches, etc.) amounts to 308,000 gallons per day, or 0.308 MGD. Cumulatively, these facilities withdraw close to the permitted pumping rate for the Town of Exmore. Industrial withdrawals exceed that of the public facilities. The two poultry industries, Perdue Inc. and Holly Farms (Tyson Foods) account for forty-two percent (42%) of the total permitted amount for industry. The following graphs compare withdrawals to permitted amounts. Figure 2-13 shows the seasonal fluctuations in water use during 1990. Private Water Use With only seven towns having public water systems, the majority of residents on the Eastern Shore of Virginia obtain their drinking water from private domestic wells. Some of these wells are shallow and withdraw water only several feet below the water table. The Virginia Water Project Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 2-22 Inc. (1988) estimates that on the Eastern Shore, the number of year-round housing units with individual drilled wells, individual dug wells, or some other private water source is 14,035. At a per household use of 165 gallons per day, private water use exceeds 2.3 million gallons per day. Another method of estimating private water use involves subtracting the number of people served by public water systems as listed by the SWCB (13,246), and multiplying the remaining 1990 US Census population (31,518) by an average of 55 gallons per day. By this method, private water use is 1.7 million gallons per day. Poultry The State Water Control Board estimates that a chicken uses 0.09 gallons of water per day (SWCB, Bulletin #60, 1983). With a 1990 production of 21 n-dllion chickens and an average 45 day life span, on any given day there were 2.6 n-dllion chickens, and these consumed a total of 234,000 gallons per day (0-234 MGD)- This is roughly close to the permitted withdrawal rate for the Town of Onancock. While it would seem safe to assume that chickens consume the same quantity of water today as they did in 1983, current practices may have increased the poultry water use. In the summer of 1991, temperatures hovering around 100*17 for several days in a row caused widespread mortality among chickens on the Delmarva Peninsula. Chicken growers reported trying the technique of misting the chickens with water and blowing fans on them to keep their body temperatures down (The Washington Post, July 25,1991, Section B). This new procedure may or may not use significant quantities of water, and it may be unique to rarely hot years; nevertheless, it may account for an increase in water consumption attributed to poultry. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 2-23 Figure 2-10: Industrial Water Withdrawals vs. Permitted Amounts Eastern Shore of Virginia, 1985-1990 16- 14- -0- Ind. Withdrawal 12- Permitted 0 10- 6- 4- 2- 0 1984 1985 1986 1987 1988 1989 1990 1991 Years Source: Virginia State Water Control Board Note: All of the industrial withdrawals were permitted prior to 1985. Figure 2-11: Public Water Withdrawals vs. Permitted Amounts Eastern Shore of Virginia, 1985-1990 16- 14- 12- -0- Pub. Withdrawal -*- Permitted 10- ----- 0- 6- 4 At*- 2- 0-- 1984 1986 1988 1990 1992 Years Source: Virginia State Water Control Board Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 2-24 Figure 2-12: Public and Industrial Withdrawals vs. Total Permitted Eastern Shore of Virginia, 1985-1990 16- 14 - ------- - - ----- 12-- 0--010, -0- Withdrawals 10- -0- Permitted 8- 6- --------------------------- 4 2 0 1984 1986 1988 1990 1992 Years Source: Virginia State Water Control Board Figure 2-13: Public and Industrial Water Withdrawals by Month, 1990 Eastern Shore of Virginia 100- 90 4L 80 - 70 ----A PUBLIC 60 INDUSTRIAL so- ------ 40 ------ ---- 30 - zu 10 0 Jan Feb Mar AprMayjun Jul Aug Sep Oct Nov Dec MONTHS Source: Virginia State Water Control Board Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 2-25 I I I I I CONTAMINATION THREATS 1 3 1 I I I I I I I I I I I I SECTION 3 - CONTAMINATION THREATS In order to formulate an effective ground water protection strategy, it is necessary to analyze past, existin& and potential land uses. Sources of contamination must be assessed in order to be able to answer questions about present conditions and to make predictions about the long-term viability of the water supply. Because monetary resources are often limited, localities must prioritize their efforts by addressing those contaminant sources of most concern. In this section, several categories of potential contaminants such as waste water disposal, agriculture, industry, solid waste disposal, and septage disposal are examined. Almost all of the ground water quality threats identified in the following section will have an impact on the Columbia aquifer on the Eastern shore. These land use threats discharge contaminants directly to the land surface or shallow ground water system. Only where public water supplies receive recharge from the Columbia aquifer would these threats be possible sources of contamination to those drinking water supplies. Many older wells serving private homes were drilled into the Columbia aquifer, and the threats outlined here are pertinent to owners of those wells. Sources of contaminants can be broken down into two general categories: point source and non-point source. Point sources refer to easily-identified sources of contamination that typically concentrate waste discharges into a single point, such as sewage treatment plants and certain industrial discharges. Nonpoint sources refer to widespread sources of contamination which present significant threats to ground water quality. Road runoff drainage is an example of a nonpoint source of contamination to ground water. Many of these sources exist without specific discharge permits and water quality monitoring requirements. Individually, each source may not represent a serious threat to ground water supplies, but cumulatively they may. Most of the potential contamination on the Eastern Shore falls into the non-point source category. Figure 3-L Typical Sources of Contamination to Ground Water LAMB shabw Wd Shdow Wes Lhdwraind [email protected] Taq*k _T 7T-T Law" FuW 01 X; h' X.:XXX. Wow fol Ground Water Supply Protection and Managernent Plan for the Eastern Shore of Virginia 3-1 WASTE WATER DISPOSAL The majority of residents (92%) on the Eastern Shore of Virginia use private septic systems for discharge of household waste water (HWH calculations based on 1990 US Census). Two towns on the mainland of Virginia's Eastern Shore have public sewage systems. Larger facilities, such as industries, restaurants, and hospitals have permitted treatment facilities or are able to discharge waste into mass drainfields. Public Sewage Systems At present, there are only three incorporated towns with public sewage facilities. The towns of Onancock, Cape Charles, and Tangier Island have facilities which serve approximately 659 residents on Tangier Island and 1,398 in Cape Charles. It is unclear how many additional residents are served outside of Onancock's town population of 1,434. According to the Northampton Country Comprehensive Plan (1990), the Exmore/Willis Wharf area is planning to construct a central sewer system which would serve approximately 2,684 people. In addition, sewering is anticipated for the DeCanio property, and Northampton County now requires central sewage facilities for any large- scale development (County Planner, John Humphrey,1990). The three sewage systems are designed to discharge at rates ranging from 100,000 to 250,000 gallons per day. It is estimated that town facilities are the largest sewage discharge systems in the two counties, other than the two poultry industries, Perdue Inc. and Holly Farms. Table 3-1: Public Sewage Facilities Recehd= Stream Design Flow (MGD) [email protected] N. Branch-of Onancock Creek 0.25 Tangier Island Chesapeake Bay 0.10 CaI26- Charles CaM Charles Harbor 0.25 From a ground water quality point of view, these sewage facilities present very little threat to the resource since they discharge to surface bodies of water at the coasts rather than on land. Discharged water is not available for recharge to the surficial aquifer or to the deeper confined aquifers. However, these sources clearly present potential threats to estuarine water quality. On-Site Septic Systems Septic systems are the leading contributor to the total volume of waste discharged directly into the ground (more than a trillion gallons annually from residents in the U.S.), and according to the US EPA (1986), septic systems are the major source of ground water contamination. Contaminants introduced from septic systems include nitrate-nitrogen, coliform bacteria, viruses, and a variety of organic and inorganic chemicals from household products. In addition, sixty percent (60%) of the 23 n-dllion residential septic tanks in the United States are believed to be operating improperly (Weigmann and Kroehler, 1988). Septic systems are comprised of a septic tank, distribution box, and a leaching facility. The septic tank provides for the separation of solids and liquids, during which time some waste is treated. The distribution box funnels waste to the leaching facility, where the liquid water is deposited into the soil. If septic tanks are not properly maintained by pumping every few years, solids may pass to the leaching facility causing plugging, backups into the dwelling, or breakouts of effluent on Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-2 the land surface. Once this has occurred, corrective actions are expensive and may result in ground water contamination if septic cleaners containing solvents are utilized. Figure 3-2. Septic System and Ground Water Contmiination Evapotranspiration Well Leaching Fft [email protected]!;@ Za --" Field Septic Tank" Soil Adsorption Distribution Box z.:Z Biological Unsaturated Zone Treatment "[email protected] ---Water und MR. . . . . . ........ Conventional septic systems provide only minimal treatment of wastewater, and release effluent contains approximately 40-60 mg/I nitrogen. As the effluent n-dxes with ground water and moves downgradient, the nitrogen becomes more dilute. Given local geologic conditions, a flow distance of several hundred feet is required to reduce concentrations to meet the drinking water standard of 10 mg/I for nitrate-nitrogen (see Section 9). The cumulative effects of numerous small septic systems may result in excessive nutrient concentrations in ground water and downgradient surface waters. These impacts are dependent upon locations of septic systems relative to wells and the overall septic system density. As noted above, the public sewer systems on the Eastern Shore of Virginia serve just over 3,000 people out of a total of 44,000, and the majority of residents use private septic systems to dispose of human waste. In a 1986 study, the Virginia Water Project estimated that there were 12,105 year- round housing units in Accomack County and 5,008 in Northampton County which had septic tanks, cesspools, or other sewage disposal means (not public). It was also estimated that in both counties there was a total of 1,359 homes with failing or inadequate disposal systems. The results are summarized in the following table. Table 3-2: Residential Disposal of Septic Wastes Year-round Housing Units Estimated GPD ACCONMCK COUNTY Served by public sewer 1,044 156,600 With septic tank or cesspool 10,077 1,511,550 With other sewage disposal means 2,028 304,200 NORTHANCPTON COUNTY Served by public sewer 934 140,100 With septic tank or cesspool 3,948 592,200 With other sewage disposal means 1,160 174,000 IMAI. 191% 2,878.65 Source: Water For Tomorrow, Virginia Water Project, Inc., 1988 aSeptic Tank [email protected] Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-3 Based on calculations from the nitrogen loading section (Section 8), approximately 381,000 pounds of nitrogen are discharged to the ground water of the Eastern Shore from on-site septic systems per year. Proper maintenance of septic systems includes periodic pumping of solids (septage) from the tank. On the Eastern Shore, the contents are brought to one of three privately-owned septage lagoons. These are described later in this section. Virginia Pollution Discharge Elimination System (VPDES) Permits and Mass Drainfields There are numerous industries that are required to obtain a discharge permit in order to dispose of wastewater. According to State Water Control Board Regulations, those applying for land application of sewage, sludge, or industrial waste must obtain a Virginia Pollution Abatement Permit (VPA). Discharging of pollutants from a point source to surface waters requires a Virginia Pollution Discharge Elimination System (VPDES) Permit. The major VPDES dischargers on the Eastern Shore of Virginia are Holly Farms, Perdue, and the Wallops Island Flight Facility. The remaining establishments have small design flows. Table 3-3 lists those industrial and public VPDES permit holders. There are 76 facilities that dispose of waste water in mass drainfields. Mass drainfields are simply larger septic systems that are shared by more than one building, residence, or industry. Such facilities typically include restaurants, schools, and campgrounds, however they can also be associated with several single family residences. The discharge rates of these facilities are not high; in fact, combining all these facilities would not equal the discharge rate in gallons per day of Holly Farms alone. Table 34 identifies these facilities. AGRICULTURE Agricultural practices introduce two "s of contaminants, pesticides and nitrate-nitrogen from fertilizers and livestock. These chen-dcals can pose serious threats to human health in excessive concentrations. Nitrates are particularly dangerous to infants. Ingesting too much nitrate-nitrogen can result in methemoglobinen-da, or "blue baby syndrome". Asphyxiation can occur when the nitrate-nitrogen that is ingested is reduced to nitrite and is absorbed into the circulation system. Nitrite reacts with hemoglobin to produce a compound that does not carry oxygen, thus depriving an infant of oxygen. The EPA recommends that nitrate-nitrogen levels in drinking water be less than 10 mg/l. The serious toxicity of pesticides has been widely reported in the cases of Agent Orange and DDT. On the Eastern Shore where private wells are commonly less than 300 feet deep, one pesticide, Aldicarb or Temik, has been detected in drinking water (Weigmann and Kroehler, 1988). Aldicarb is highly soluble and mobile in water. Agent Orange and DDT were banned decades ago. Aldicarb is no longer used. Fertilizers High application rates of commercial fertilizers over large areas of land have been shown to contribute nitrogen to the ground water in an agriculturally intensive region like the Eastern Shore. Publications and studies supporting this hypothesis are numerous. For reference, a selection of examples include: USGS, 1989, p. 38; EPA, 1990, pp. 125-128; Association of Ground Water Scientists and Engineers, 1989, p. 262; Miller, David A., 1980, pp. 430-431; Ground Water Quality Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 34 Protection, State and Local Strategies, 1986, p. 84, p. 145; Ground Water Pollution News, 1989,pp. 1- 2. However, as stated on page 14 of this document, the average nitrogen concentration in the ground water was calculated to be 2.0 n-dlligrams per liter. The national drinking water standard for nitrogen is 10 milligrams per liter. On the average, the shallow ground water quality is considered very good, however users down gradient from high nitrogen use may experience problems. Farmers generally follow recommended fertilizer application amounts. This makes it possible to estimate the quantities of nitrogen fertilizers applied to each crop type. Using 1990 crop acreage figures, agricultural practices required approximately 5.8 million pounds of nitrogen in fertilizers. Table 3-5 presents a breakdown of nitrogen requirements by crop type. Approximately 6.7% of the land is fertilized with manure; the remainder is supplied by commercial fertilizer (Accomack County Extension Agent, J. Belote, personal communication, 1991). Out of a total of 165,000 acres of farmland, 94,000 are used for soybeans, a crop which requires no nitrogen fertilization because the plant is a nitrogen-fixer. Current methods for the Eastern Shore recommend that fertilizer be applied in two stages: a small amount at planting, the rest after growth occurs. In the case of corn, this second application occurs when the plant has reached ankle height. The fertilizer is side-dressed, which means that it is dribbled on each TOw at each plant, so that a small amount is wasted in the soil. With the implementation of side-dressing and the new phased technique, the intention is to hold leaching of nitrogen to a minimal amount. However, USGS sampling that is representative of current and/or recent fertilization practices shows a concentration of 20-25 n-dlligrams per liter (mg/1) nitrate- nitrogen in ground water beneath farm fields in the shallow flow system (G. Speiran, USGS, personal communication, 1991). Historically, the number of farmers and the acres farmed have been declining since 1930. The type of crops grown has also changed. Whereas crops grown in the earlier half of this century were of the garden vegetable kind and required fertilizers, today's crops are mainly soybeans and are not fertilized. Still, significant amounts of fertilizers are presently used, as shown in Table 3-5. Also, both the Accornack and Northampton County Comprehensive Plans see agriculture as continuing to be the main land use in the future. Thus, although nitrogen fertilizer use has been decreasing, it remains relevant to look towards agriculture as a potential source of contan-driation to ground water, both from former and current practices. For this study, 89 and 79 lbs/acre were used as average nitrogen application rates in Accomack and Northampton counties respectively. On a smaller scale, home owners in general use fertilizers as a part of lawn maintenance. Nitrogen loading from lawn fertilizers was studied by Nelson et al. in 1988. They detern-dned that, on average, the homeowner applies 3 lbs. of nitrogen for every 1,000 square feet of lawn per year. With a leaching rate of 30%, 0.9 lbs. of nitrogen are leached into the ground water system for every 1000 square feet of lawn. On the Eastern Shore, lawn maintenance is not a high priority. Pesticides Pesticides include a wide variety of chen-dcals utilized for the control of animal pests, insects, fungi, and weeds. Factors which affect the level of risk for contan-tination include the specific chen-dcal formulation, rates of application, timing of application, soil conditions, and hydrologic conditions. Those that have a low solubility, are degraded by sunlight, or react with water to produce new compounds are not likely to contaminate ground water. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-5 Table 3-3: Facilities With Discharge Permits, Eastern Shore, Virginia C) Accomack County Plant Outfall Flow (MGD) Facility Name Ind/Mun VPDES# C11 Receiving Stream Latitude Longitude Design Accomack Co. Nursing Home M VA0063606 N. FORK PARKER CREEK TO METOMPKIN BAY 374537 753719 OR2 Bonawell Brothers Seafood I VA000420i Saxis POCOMOKE SOUND 375515 754350 *.001(4) Chincoteague Fish Co. I VA0051462 Chincoteague CHINCOTEAGUE CHANNEL 375600 752254 Chincoteague WTP I VA0051756 Chincoteague CHINCOTEAGUE CHANNEL 375605 752239 Drewer & Son, Inc. REEK 375512 754351 *.035,.018(4) I VA0081361 Saxis STARLING C Edgerton, D. 1. Fish Co. I VA0055239 Chincoteague CHINCOTEAGUE CHANNEL 375612 752227 *161 Edgewood Mobile Home Park M VA0065196 New Church TRIB TO TUNNELS MILL BR TO BULLBEGGER CRK 375709 753216 0.006 External Assist. Sys. Pension Trust M VA0078204 Route 13 TRIB TO TUNNELS MILL BR TO BULLBEGGER CRK 375655 753238 0.035 F&G Laundromat I VAOD50M Chincoteague CHINCOTEAGUE CHANNEL 375600 752200 *0.005 lu Fisher, Lance G. Seafood Co., Inc. I VAM79448 Sanford POCOMOKE SOUND 3755W 754130 *.02(4) Hills Oyster Farms I VA0058874 Chincoteague DEEP HOLE CREEK TO LITTLE OYSTER BAY 375612 752057 Ifolly Farms I VA0004049 Temperanceville SANDY BOTTOM BRANCH TO HOLDENS CREE K 375325 753339 098 Kuzzens, Inc. I VA0081809 Painter DITCH TO TAYLOR BRANCH TO OCCOHANNOCK CRK 373352 754803 Lewis Oyster Co. I VA0057673 Saxis STARLING CREEK TO POKOMOKE BAY 375511 754353 'no discharg ;% Marshall, William H. & Co. I VA0058360 Greenbackville CHINCOTEAGUE BAY 380022 752326 McCready Seafood I VA0095690 Chincoteague EEK CREEK TO CHINCOTEAGUE BAY 375546 752232 'no discharge Messick & Wessells - Nelsonia I VA00514ff- Nelsonia MUDDY CREEK 374916 753515 *0-005 Messick & Wessells - Onley I VA00539W Onley JOYNES BRANCH TO ONANCOCK CREEK 374134 754244 *0.005 Nandua Seafood Co., Inc. I VAOD51161 Hacksneck BACK CREEK TO NANDUA CREEK 373802 755252 New Curch Energy Associates I VA0058521 NewChurch UNNAMED TRIB TO PITTS CRK & POCOMOKE SOUND 375858 753254 North Accomack Elem. School M VA0027162 Mappsville UNN. TRIB TO MESSONGO CREEK TO POCOMOKE BAY 375128 753357 0.5F9 Onancock WTP M VA0021253 lonancock N. BRANCH OF ONANCOCK CREEK 374258 75"52 025 Perdue, Inc. I VA0003NO Accomac PARKER CREEK TO METOMPKIN BAY 374410 753920 *1.7,.01(4) Reed, Thomas E. - Seafood, In. I VA0005738 Chincoteague DEEP HOLE CREEK 375621 752045 1611 Russell Fish Co. I VA0054003 Chincoteague CHINCOTEAGUE CHANNEL 375559 752255 *161 South Accomack Elem. School M VA0027171 Melia UNNAMED TRIB TO WAREHOUSE POND 373920 754738 0.009 Stubbs, Reginald - Seafood Co, Inc. I VAOD56421 Chincoteague ASSATEAGUE CHANNEL 375501 752224 6.002(4) Tangier WTP, Town of M VAOD67423 Tangier Cl IESAPEAKE BAY 374940 760035 0.1 Taylor, I.W. - Packing I VAOOOZM Hallwood MESSONGO CREEK TO POKOMOKE SOUND 375224 753529 0.1 Taylor & Fulton, Inc. I VA0082538 Mappsville UNNAMED TRIB OF ASSOWOMAN CRK TO ASSOWOMA 375216 753319 US - NASA Wallops Flight Facility M VAOD24457 Wallops Island HOG CREEK AND MOSQUITO CREEK 375550 752859 0.8 & 0.03 Vasiliou, Tom - STP M VA0082297 Oak Hall TRIB TO TUNNEUS MILL BR TO BULBEGGER CRK 375649 753233 0-001 VDOT - Rt. 13 Information Center M VA0023078 New Church TRIB TO PITTS CREEK 375927 753213 O.F2 VDH - Septage Lagoon - Boggs 01 VDHSLBO-01 Wachs rea ue eventually to Nickawampus Crk. to Finney Creek 373738 754222 VDH - Septage Lagoon - Bundick 01 VDHSLBU-01 Atlantic to Little Mosquito Creek 375538 753158 VDH - Septage Lagoon - Bundick 02 VDHSLBU-02 Mappsburg to Machipomgo River 373405 754611 Virginia Carolina Seafood Co., Inc. I VA0050997 Chincoteague WATTS BAY 375432 7528311 !4* Watkinson, Paul - Seafood I VA0050491 Saxis- POCOMOKE SOUND 375511 754354 [WWis-pering Pines Motel IVAOMM71 ITicktown JUNNAMED TRIB TO DEEP CREEK 374 20 7541411 019 Table 3-3. Facilities With Discharge Permits, Eastern Shore, Virginia C) Northampton County Facility Name Ind/Mun VPDES# City ReceivinIt Stream Latitu e ongiiude Design America House Motor Inn M VA0064921 Cape Charles CHESAPEAKE BAY 370813 755807 0.02 American Original Corp. I VA0029M Willis WharF- PARTING CREEK TO MACHIPONGO RIVER 373045 754824 *.151(4) Ballard Fish & Oyster Co. F VA0073679 Cheriton KINGS CREEK 371658 760039 Bayshore Concrete Prod. - Cape Chad. I VA008%77 Cape Charles CAPE CHARLES HARBOR 371541 760131 Bell, B.L. & Son I VAOM4219 Oyster OYSTER HARBOR 370-09 755532 .001(4) Broad Street Laundry I VA0056502 Exmore UNNAMED TRIB TO NASSAWADOX CREEK 373138 7549301 z BFoadwater Bay Seafood I VA0086126 Marionville REDBANK CREEK TO I IOG ISLAND BAY 372644 755033 :9 C&D Seafood I VA0002917 Oyster OYSTER HARBOR 371715 755520 stopped d is. q1- Cape Charles Fish & Scallop, Inc. I VA0083283 Cape Charles CAPE CHARLES HARBOR 371548 760100 Cape Charles STP M VA0021288 Cape Charles CAPE CHARLES HARBOR 371550 760100 0.25 Cheriton Laundry, Inc. I VA0051136 Cherilon TRIB TO KINGS CREEK 2M2 755735 Eastville Laundromal I VA005"37 Easiville OLD CASTLE CREEK 3720381 755716 Hamblin, I.E. - Seafood I VAOO&%93 Willis Wharf PARTING CREEK TO MACHIPONGO RIVER 373130 754815 'no discharge KMC Foods, Inc. I VA0054119 Cherilon HANDY BRANCH 371744 755733 Machipongo Elem. School M VA0023817 Machipongo UNNAMED TRIB TO JACOBUS CREEK 372429 755458 0.0208 Northampton-Accomack Memorial Hosp. M VA0027537 Nassawadox WAREHOUSE CREEK TO NASSAWADOX CREEK 372839 755144 0.1 R&C Seafood Co. 11 VA0052264 Oyster OYSTER SLIP 371715 755515 Terry, H.M - Co., Inc. if @MT9K Willis Wharf PARTING CREEK TO MACHIPONGO RIVER 373037 754821 -.0004(4)1 1:5 West, John H. 11 VA0083437 Oyster OYSTER HARBOR 1 3717141 7555 Source: figure comes from the Water Quality Mgt. Plan, SWCB, NOTE: (2) NPDES permit limits (1980) 1980. The remaining numbers are up to date (1991) from the SWCB. They (4) Estimated do not have flows for industrial facilities except Holly Farms and Taylor Packing. (6) No limits - has an NPDES permit, but is not required to monitor (things like crab shedding) Table 3-4: Facilities Using Mass Drainfields, Eastern Shore, Virginia FACILITY NAME TOWN gallons per day ACCOMACK COUNTY Virginia Landing Quinby 90000 Tom's Cove Accomack County N/A Trail's End Chincoteague Bay Horntown 20000 Inlet View/Bunker Hill N/A N/A Maddox Family Campground Chincoteague N/A Pine Grove Campground Chincotea ue N/A Island Motor Inn Chincoteague 6400 Refuge Motor Inn Chincoteague 8800 Driftwood Motor Lodge Chincoteagu 6700 Chincoteague Motor Lodge Chincoteague 9360 Waterside Motor Inn Chincoteague 5700 Conner & McGee Chincoteague 3300 Eastwind Townhouse Chincoteague 9600 Assateague Inn Chincoteague 4040 Don's Seafood Market & Restaurant Chincoteague 4000 Seatag Lodge Chincoteague 3000 Birchwood Motel, Inc. Chincoteague wo Mulberrv Street Townhouse Chincoteague %00 David P. Burgess Townhouse Chincoteagu 2700 R&S Drv Cleaning & Laundry Chincoteague N/A McDonald's Chincoteague 4000 ETTAS Restaurant Chincoteague 4300 Landmark Crab House Chincoteague 12500 R&S Laundromat Chincoteague 5500 Mr. Chocolate Island Creamery Chincoteague 4500 Oak Ridge Townhouse Chincoteague 9000 Reed Triplexes Chincoteague 2700 Chincoteague High School Chincoteague 4000 Chincoteague Elementary Chincoteague 2000 Parks Mobile Park Oak Hall 7200 Pizza Hut Oak Hall 2500 Arcadia High School Accomac 6912 Wright's Seafood Restaurant Atlantic 5000 Eastern Shore Seafood Production Mappsville 1500 Bvrd Foods Mappsville 2000 Parkslev Middle School Parksley 2000 Red & 'White Stores Parksley 1500 St. Paul's Lutheran School Hallwood 3000 Bi Countv N.H. Nursing Center Gargatha 6400 Accomac Office Complex Accomac %00 Mary N. Smith Middle School Accomac 6000 Nandua High School Onley 13826 Redwood Gables Restaurant Onlev 1800 Chesapeake Square Shopping Center Onlev 12000 Four Corners Plaza Onley 12000 Eastern Shore Comm. College -.Melfa 12000 Ches-Atlantic Painter 1500 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-8 Table 3-4: Facilities Using Mass Drainfields, Eastern Shore, Virginia FACILITY NAME TOWN gallons per day Exmore Moose Lodge Belle Haven 5000 Kuzzen's Ames Farm/ MLC Painter 10500 Peerless Sterling Bull Camp Modest Town 1200 Peerless Sterling Gargatha Temperanceville 4500 Peerless Sterling Somers Farm Bloxom 4500 Peerless Sterling Lakeview Accomac 2600 Taylor & Fulton Inc. Hallwood 9000 Taylor & Fulton Poulson House Hallwood 1500 Virginia Farms/ Farm Exchange Taslev 1500 Ravmond A. Last-VPDES Chin oteague___ 7650 Willett's Laundromat-VPDES Lee Mont 3200 Accomack TOTAL 394988 NORTHAMPTON COUNTY Cherrystone Holiday KOA Northampton Co. Paul's Restaurant Cheriton 3500 Capeville Campground Northampon Co. 7500 Cheriton Day Care Cheriton 2000 Trawler Seafood Restaurant Exmore 700 Hardees Exmore 2500 Silver Beach Camping Silver Beach 2700 Broadway Academy Exmore 3000 McDonald's Nassawadox 4500 Anchor Motel Restaurant Nassawadox 7640 Candlelight Restaurant Birdsnest 5760 Holidav Motel Townsend 18000 Burger Unlimited Eastville 1500 Curtis Jones & Son Packing Sh Eastville 2240 Kuzzens - Newman Eastville 1800 Northampton High School Eastville 16000 Cape Center Inc. Capeville 2500 Holidav Acres Mobile Home Park Weirwood 4800 Curtis Jones, Jr. Bavford 1550 P.C. Kellam Potato Shed Bridgetown 2000 Northampton TOTAL 90190 GRAND TOTAL 485178 Source: Virginia Tech (N/A indicates information not available) Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-9 The primary crops grown on the Eastern Shore of Virginia are soybeans, small grains (wheat and barley), potatoes, a variety of garden vegetables, and some ornamental plants. Several different types of pesticides are used depending on the pest, crop type, and application requirement. These factors significantly vary from farm to farm. Since there is no formal reporting of pesticide use, other than that of restricted-use pesticides, it is impossible to sum-dse the quantities and brands that are applied each year. As such, it need be stressed that the leaching of pesticides into the ground water is a threat to water quality and should be monitored. Animal Wastes and Animal Carcasses Animal wastes can contaminate ground water with nitrate-nitrogen and bacteria. In 1990, 21 million chickens were raised for poultry on the Eastern Shore of Virginia. Commercial poultry is the only significant livestock industry in the area, and is contained entirely within Accomack County. Commonly, contan-tination results from feedlots and improperly constructed or leaking manure storage piles or pits. Eastern Shore chicken growers apparently do not store wastes in such piles, but instead clean the chicken houses out once or twice yearly whereupon the manure is spread onto the farm land. The Virginia State Extension Service reports that for every thousand chickens, one ton of poultry manure is produced (W. Weaver, Virginia Tech, personal communication, 1991). Tests done by Perdue and Tyson of 57 poultry litter samples indicate that nitrogen constitutes 44.73 pounds per ton of manure (Virginia Tech, 1991). Therefore, in 1990,21,000 tons of poultry manure was produced, contributing a total of 940,000 pounds (470 tons) of nitrogen. During the year or so that manure remains in the chicken houses, some of the nitrogen volatizes. However, on a weight basis, chicken manure has the highest nutrient availability rate, compared to that of horse, cattle, and hog manure. While this makes it a good fertilizer, it is also most easily leached into ground water. In large quantities, chicken carcasses can also pose a threat to ground water quality. A natural mortality rate of about 5% creates a need to dispose of dead chickens. Assun-dng that the majority of chickens die within the first two weeks after hatching, mortality of dead birds can be split between those that die at 0.5 lbs. and those that die weighing 3 lbs (C. Larsen, Virginia Tech Veterinary Medicine, personal communication, 1991). A 5% mortality rate accounts for 1.05 million dead birds in a year with a population of 21 n-dllion chickens. Multiplying half of those by 0.5 lbs. and half by 3 lbs. gives a yearly rate of 1.84 million lbs. of dead birds. Dead chickens are disposed of in one of four ways: burial, incineration, composting, or rendering for use as chicken or hog feed. In Accomack County, the Tyson rendering plant is available for growers. The facility is used by growers primarily during times of abnormally high mortality. An estimated 400,000 lbs. are brought to the rendering plant per year, but there is no data to support this. The one facility that had been incinerating has decided to compost, since it is more econon-dcal (J.R. Lewis, SCS, personal communication, 1991).The majority of dead birds are thus either buried or composted. Burial (or dumping in the woods, in some cases) poses a threat to ground water quality. Section 9 briefly discusses composting. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-10 Table 3-5: Nitrogen Fertilizer Requirements, Eastern Shore of Virginia ACCOMACK COUNTY Crop Type 1990 Acreage Recorarnended lbs. N Used N in lbs/acre Soybeans 62,000 0 0 Corn 51500 75-175 687,500 Small grains 25,000 50-80 1,625,000 Irish potatoes 5,500 150 825,000 Sweet potatoes 1,600 W7-5 100,000 Talked tomatoes 2,200' 80-90 187,000 Snap beans (Spring) 1,000 40-80 60,000 Snap beans (Fall) 2,300 40-80 138,000 Cucumbers (Spring) 1,000 100-125 112,500 Cucumbers (Fall) 2,000 100-125 225,000 Others 2,500 50-150 2.50,000 Ornamentals 700 Grapes and Orchards 120 Accomack Total 47,420 4,210,000 N applied acres Average N Application (lbs/acre)* 89 NORTHAMPTON COUNTY Crop Type 1990 Acreage Recommended lbs. N Used N in lbstacre Soybeans 32,000 0 0 Corn 500 75-175 K2 500 Small grains 12,000 50-80 780,000 Cotton 1,300 60 78,000 Potatoes 2,500 50-150 250,000 Snap beans (Spring) 600 40-80 36,000_ Snap beans (Fall) 600 40-80 36,000- Zucumbers (Spring) 8W 100-125 90,000 Cucumbers (Fall) 800 100-125 90,000 Tomatoes 650 80-90 .55,2-50_ Peppers 100 100-130 11,500- Spinach 280 100-125 31,500 Nursery 840 1 1 10thers 1 1,000 1 50-150 1 100,000 Northampton Total 20,570 1,620,750 N applied acres Average N loading (lbs/acre)* 79 TOTAL FERTILIZED 67,990 5,830,750 *Total Average Nitrogen Loading: 84 (Calculated by subtracting out Spring Acres Double Cropped) Sources: Fact Sheet - Accomack County, 1989 National Survey of Conservation Tillage Practices, personal conversation with Northampton Extension Agent Fred Diem, 2/26/91 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-11 IKDUSTRIAUCONUvEMCIAL LAND USES Underground Storage Tanks Petroleum stored in underground storage systems is one of the greatest national threats to ground water quality. The EPA estimates that approximately one-third of all existing systems nationwide are currently "non-tight", or potentially leaking. The average expected life span of unprotected steel tanks in acidic soils is approximately 15 years, although new steel underground storage tanks are warranted for 30 years. After time, corrosion may begin, resulting in pin-hole sized leaks which may discharge hundreds of gallons of fuel over a several-month period. These leakage rates are small enough to go unnoticed to the tank owner for several months, but are large enough to cause significant ground water contamination problems. Gasoline contains a variety of components including benzene, toluene, and xylene, all which are known to have negative health affects. Newer tanks are being constructed with materials resistant to corrosion and with cathodic protection, which is aimed at decreasing the likelihood of leakage. A total of 1,154 underground storage tanks are located in Accomack and Northampton Counties. Of these, 684 or (59%) are over 15 years old. The majority of all storage tanks store gasoline and are made of steel. Together, they have a storage capacity of 4,462,347 gallons. Figure 3-4. Underground Storage Tanks Broken Down By Age and Wellhead Protection Area, Eastern Shore of Virginia 200- 175- 150- 125 - > 15 years < 15 years 100- 75-- sol Z 25- 0-- WPA A WPA B WPA C WPA D WPA E Wellhead Protection Area Source: Virginia State Water Control Board rmiz Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-12 Underground storage tanks were grouped by Wellhead Protection Area (WPA) in Table 3-6. WPA's are introduced and described in Section 5. WPA C, which covers the largest land area, also has the greatest number of underground storage tanks, with a total of 329. The remaining wellhead protection areas all contain close to 200 tanks. The town of Chincoteague, located in WPA A, contains 129 tanks which is the most located in any one town. WPA A also has the highest percentage of storage tanks older than fifteen years. State Water Control Board records indicate that there have been leakage problems in several tanks in the two counties. Of the total, 3.6% of the tanks in Accomack and Northampton Counties have been reported as leaking. As of July 3, 1991, there are twenty-nine contan-driated sites in Accomack County, and twelve contan-dnated sites in Northampton County. A column in Table 3-6 on the next page identifies the leaking tanks by town and wellhead protection area. WPA A has the highest percentage of leaking underground storage tanks, with 9 out of 199 tanks leaking (4.5%). According to the SWCB, seven tanks in Accomack County and one in Northampton County have been closed and are no longer leaking. Only two tanks in Accomack County have a monitoring program underway. It may be of interest to determine which of the leaking and non-leaking tanks lie on the spine recharge area, and install monitoring programs for those tanks. TO)CIC CHENUCALS A wide variety of commercial and industrial land uses represent contamination threats to ground water. Small scale businesses such as auto body shops or dry-cleaning establishments, which may not be regulated by federal or state laws, utilize significant quantities of toxic chen-ticals such as solvents. Accidental or inappropriate disposal of hazardous wastes, even in small quantities, may result in ground water contamination exceeding state and federal drinking water standards. For example, many of the drinking water standards for volatile organic compounds (VOC's) are in the low parts-per-billion range. Industries are required to report use and manufacturing of chen-dcals under several federal and state laws. EPA's Toxic Substances Control Act (TSCA, P.L. 94-469) requires that all manufacturers or importers of chemical substances be identified. Under the Superfund Amendments and Reauthorization Act (SARA, 1986), specific chemicals and amounts used must be reported. In Virginia, the Toxic Substances Information Act of 1976 requires that all businesses must report all chen-dcals that are manufactured or used in the manufacturing process. Reports must be updated annually. On the Eastern Shore of Virginia, there are no Superfund or toxic dump sites. Several industries do use toxic materials, however. Tables 3-7 and 3-8 identify these industries as reported separately to the State and to EPA. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-13 Table 3.6 UndwpvwW Storap Tudw by Wellhead P owedw Am WPA TOWN NUMBERS TANX7YPE PILOOLMT 20OWS CAL Act ACCOMACK COUNTY COUNT LEAKING STEEL FZL4SS UNKN. DIESEL GAS X3ERO FZEL UjOIL CAPACITY 3-ISyn <15yn A CHINCOTEAGUE 129 2 126 2 1 9 54 11 32 1 -- ISL955 v 42 GREENBACKVILLE is a 15 0 0 5 10 0 0 0 10.25 12 3 HORNTOWN 12 0 12 0 0 0 4 0 8 0 10AS 10 2 NEW 01URCli 20 3 20 0 0 3 13 1 1 0 90.9 9 11 WALLOPS STATION 3 4 3 0 0 2 0 0 0 1 12M 3 0 WATTSVILLE 20 0 20 0 0 2 is 1 2 0 8DA 10 10 total 1" 9 196 2 1 21 % 23 63 2 3SL305 232 a ATLANTIC is 0 is 0 0 1 a 4 5 0 17M 11 7 HALLWOOD 11 1 8 0 3 0 5 1 2 0 7AS 9 2 HORSEY 1 0 1 0 0 0 1 0 0 0 1 0 1 MAPPSV1I..LE 7 1 7 a 0 0 6 1 0 0 15.5 6 1 MEARS 3 0 3 0 0 1 2 0 0 0 138 0 3 NELSONIA 21 1 19 0 2 1 16 0 1 0 79.55 11 10 OAK HALL 33 0 32 0 1 3 24 4 1 1 90.SS 11 22 TEhG%RANCBVM.LE 36 2 34 0 2 8 16 1 5 3 16625 2S 11 WALLOPS ISLAND 56 0 47 9 a 24 21 1 5 0 2137.132 40 16 WTrHAMS 3 1 3 0 0 0 2 0 1 0 1.65 3 0 total 189 6 In , 8 38 -101 12 29 4 1 2517M2 216 73 C ACCOMAC 81 1 78 1 2 11 40 11 a 3 173.64 56 25 BLOXOM 14 1 13 0 1 4 3 1 1 0 19.93 7 7 CENTERVILLE 5 0 5 0 0 0 0 0 0 16 5 0 GREENBUSH 7 0 6 0 1 1 6 0 0 0 41 6 1 LEEMONT 4 0 4 0 0 0 2 1 1 0 2.4 4 0 LOCUSTVILLE 3 0 3 0 0 a 2 1 0 0 1.22 3 0 MELFA 31 1 30 0 1 6 23 1 0 0 60.2 16 24 ONANCOCK 59 1 so 0 1 9 37 5 6 0 95.9 22 37 ONLEY 41 2 40 0 1 4 26 4 3 2 106.8 26 is PARKSLEY 62 3 60 2 0 6 40 7 4 0 113.005 31 31 TASLEY 22 1 21 0 1 a a 2 0 2 37.925 16 6 -total 329 10 318 3 a 45 197 33 23 7 631.62 192 2461 D BELLE HAVEN 23 1 23 0 0 6 is 2 0 0 11d.08 12 11 CRADDOCKVILLE 10 0 10 0 0 3 6 1 0 0 7.05 9 1 DAVIS WHARF 4 0 4 0 0 1 3 0 0 0 2.6 0 4 KELLER is a 13 0 2 2 9 2 0 1 24.63 a 7 MIDDLESEX 3 0 3 0 0 2 0 1 0 0 20.5 0 3 PAINTER 26 1 26 0 0 5 15 4 1 a 369 12 14 PUNGOTEAGUE 5 0 5 0 0 0 5 0 0 0 zis 5 0 QUINBY 4 0 4 0 0 1 3 0 0 0 2.65 0 4 WAQL4FREAGUR a 0 6 0 2 1 5 0 0 0 11.55 5 3 HARBORTON 5 1 5 0 0 1 2 1 0 0 3.65 2 3 Rotal 10ILS 3 %.S 0 4 21A 62 ILS -I I mms S2 4LS OUT of WPA SANFORD 3 3 0 0 0 2 1 0 0 im 3 0 OUr of WPA SAXIS 13 11 13 0 0 4 a 1 0 0 9.6 7 6 COUNTYTOTAL S36 29 an 24 21 L13 "7 71 207 14 37153V S02 343 NORTHAMPTON COUNTY D BAYFORD 4 0 4 0 0 1 2 0 a 0 2.2 2 2 BIRDS NEST 3 0 3 0 0 0 2 0 1 0 1.1 2 1 BRIDGETOWN 1 0 1 0 0 0 1 0 0 0 1 0 1 EXMORE 77 4 71 3 3 10 53 7 2 2 142.04 45 32 JAMESVILIX 4 0 4 0 0 a 1 0 1 0 2.2 4 0 NASSAWADOX 27 0 25 0 2 2 14 3 1 a 62.03 14 13 SILVER BEAC3-1 1 0 1 0 0 1 0 0 0 0 0.273 1 0 WEIRWOOD 7 1 7 0 0 1 6 0 0 0 17.1 2 5 WFILLIS WHARF 1 0 1 0 0 1 0 0 0 0 2 1 0 CHURCHNECK 1 0 1 a 0 0 0 a 1 0 1 1 0 total 126 5 its 3 5 16 79 10 6 2 230.943 72 54 E CAPE CHARLES 84 2 so 1 3 16 47 9 3 0 2.26.25S 49 36 CAPEVILLE 16 0 16 0 0 5 10 1 0 0 SIM 9 7 CHERMN 30 2 30 0 0 2 24 3 1 0 67A3 11 19 CHESAPEAKE 8 0 a 0 0 0 3 0 0 0 10 8 0 DALBYS 3 0 3 0 0 0 2 1 0 0 am 1 2 EASIVILLE 30 1 29 0 1 3 22 4 0 0 $6.94 14 16 MACHlPONG0 12 1 12 0 0 1 10 1 0 0 30.05 7 5 SRAVIEW 5 0 5 0 0 0 4 0 1 0 16M 5 0 TOWNSEND 4 0 4 0 0 0 3 0 0 1 ism 4 0 total 192 6 287 1 4 27 125 19 5 1 1 516.075 109 85 COUNTYTOTAL 315 12 305 4 1 43 201 29 11 3 747.02 10 IN GRAND TOTAL 1254 42 1106 is 30 176 Gn 100 Ila 17 4"2.117 6n 4n Source Virgitua State Water Comrol Board Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-14 SOLID WASTE DISPOSAL The predon-dnant form of solid waste disposal on the Eastern Shore is through landfilling. There are currently two public landfills in Accomack County and one public and one private landfill in Northampton County. Two additional landfills have been filled and are now closed. They are located in Chincoteague and northern Accomack County. Incorporated towns in the Accomack- Northampton Planning District utilize their respective county landfills for solid waste needs. Locations of landfills in both counties are included in Figure 3-5. The Northampton County landfill was opened in 1985 and is expected to be in service for 20 years. It is located less than a mile north of the village of Oyster. The entire site is approximately 174 acres, with the landfill portion containing 78 acres. The landfill is to be used in phases and is divided into four cells, each of which is expected accept waste for five years. This landfill is lined and has a leachate collection system. Sampling is conducted quarterly from six shallow monitoring wells and the leachate pond. Without conducting a detailed analysis, a review of the sampling data revealed that the wells located downgradient from the landfill are displaying poorer water quality than the background well. Monitoring of the ground water quality should continue at this landfill with the consideration of the installation of wells screened deeper in the aquifer than the current wells. The inclusion of these wells will help to detern-dne if any leachate is migrating in a vertical direction and recharging the Yorktown-Eastover aquifer. The southern landfill in Accomack County is located at Bobtown. Opened in 1973, 86 acres of its 113- acre property are filled. Virginia Department of Waste Management, Solid Waste Management Regulations require that any solid waste management facility for which a pern-dt was issued prior to the effective date of the new regulations comply with all of the provisions of the regulations by July 1, 1994. The regulations now require all landfills to be lined. The southern landfill was constructed without a liner and old landfills must either be brought up to standard or be closed by 1992. The northern landfill in Accomack County is located approximately one mile north of Temperanceville. It was permitted for use in 1985 and comprises 150 acres. The landfill has been divided into three adjacent, independent, fill areas and is estimated to handle approximately 22 tons of waste per day. At the time of construction, the projected life span of the landfill was between 20 and 30 years. At this time, approximately 9 acres have been used. Should an accident occur, this landfill poses a significant threat to the quality of ground water on the Eastern Shore since it is located directly on the spine recharge area. Any leakage of leachate from the landfill into the ground water could potentially reach the lower Yorktown-Eastover aquifer. The Northern Landfill is lined, and has two components which help reduce the chance of contamination to the ground water. First, there is a stormwater management system in place to catch water contributed by rain. The landfill is also equipped with a leachate system which collects liquids originating in the waste, all of which are stored in 10,000 gallon tanks. When the tanks fill, they are brought to a wastewater treatment plant in Onancock. This landfill has fourteen monitoring wells installed to collect ground water quality samples. These wells are sampled quarterly for a range of chemical parameters. Currently, the samples are not showing any signs of significant contan-driation of the ground water. According to the Director of Public Works for Accomack County,Joe DeMarino, there have been "no problems" with any sample results from the monitoring wells (personal conversation, 7/24/91). Sampling should continue for both the northern landfill which is currently in operation and the southern landfill which is planned to be closed. Monitoring wells with screens located deeper in the aquifer should be installed to assess any vertical n-dgration of leachate to the Yorktown-Eastover aquifer. The sample results are available for review in the Department of Public Works office in Accornac. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-15 Table 3-7. EPA List of Active Gen I a and Transfer Stange Disposal Facilities, Accontack and Northampton Countles IDS Facility Name L"ation Date Generation of Non-Acutely Other reported haraodaus waste kz/mo.) <IW 100-M > 1000 ACCOMACK COUNTY VA9143609148 Chincoteague National Wildlife Refuge Chincoteague 2/4/87 X VAD023812878 Davis Auto Center, Inc. New Church 10/28/86 x VA78000208M GSFC/NASA Wallops Flight Facility Wallops Island 4/7/19 X VAD044983658 Holly Famis Poultry Ind. lnc. Temperanceville 10/28/86 x VASNO010763 NASA Wallops Flight Center Wallops Island 8/15/8D X I LAnd Disposal VAD023864127 7Z9M-0tor Co. Inc. Parksley 10/28/86 x VAD980715312 Perdue Inc. Accornac 12/29/86 x VAD982578155 VA Dept. of Transportation Accomac 1/12/99 x VAD98267M4 Vaarrig-Armory-Onancock. Onancock 5/14/90 x VAD988172151 Whittaker Bioproducts Chincoteague 7/5/90 x [email protected] COUNTY I VAD9WO9784 Alban Engine Power, CaR=aries 12/279-9- 1 x VA-D-982565830 Bayshore Concrete Products Cape Charles 1/15/88 x VA2572124483 Cape Charies Air Force Station* Cape Charles 8/18/8D x VAD000650531 Municipal Corp. of Cape Charles Cape Charles 8/18/80 x VAD0237= Center Chevorlet, Inc. Exmore 11/24/86 x VAD009091620 Chesapeake Bay Bridge-Tunnel Wise Point 3/13/90 x VAD9881861" Chesapeake Hardware Product% Chesapeake 10/2/90 x VAD051365120 Eastern Shore Railroad, Inc. Cape Charles 7/7/86 x IVAD988194429 Exx=Co.USA*26457 Exrnore 3/28/91 X * - Currently the Eastern Shore National Wildlife Refuge. Sour= US EPA, Region ILI Cffice, PhiladelpW Table 3-8: Vu*nia To3dc Substances Chemical Inventory, Accomack and Northampton Counties SUBSTANCE Anwunt Used - (0&kg/ Facility Name Latitude Longitude jAcid 15ase Organic Nutrient 120-1001101-1000 IACI-10,000110,WI-100AM >10DA001 ACCOMACK COUNTY Harry Drarrunand, Inc. 373325 754926 x I x Easter. Shore Printers 374247 754435 X x x x A j Gray & [email protected] Inc. 375529 7-SMM331 -X x x x x x Helena Chenucal Co. 3742381 754216 X x x x x x New Church Energy Assomates 3759001 753200 x Stony Point Decoys 375647 753218. x x NORTHANIPTONCOUNTY I Bayshore Cmavft Products Corp --17-1545 7601 X# I Lebanon Chennical Corp. --f7-1606 75:W4 x x x Source: Virginia Departv%ent of Health, Bureau of To)dc Substances Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-16 00, OCEAN ATLANTIC J -1 w LANDFILL, IJOGGS LAGOON MA13ICK BUNDICK NORTHEIPIN [email protected] 002 LAGOON 001 LANDFILL =RN CHESAPEAKE LANDFILL SITE SEPTAGE LAGOON SITE L 0 22,000 33.000 scale I loot) 3-17 SEYrAGE DISPOSAL There are three anaerobic septage lagoons located in the two counties which are owned by two well-drilling companies (Figure 3-5). The lagoons are in wooded areas which are set aside as receptacles for septage. When septic tanks are periodically emptied, the waste gets dumped into these lagoons. Lagoons are usually earth-diked ponds, varying in shape and size, and are relatively maintenance-free. The entire lagoon stabilizes biodegradable organics under anaerobic conditions where the rate of reaction or stabilization is slow. Bad odors are a characteristic of these areas, and lagoons can threaten the ground water quality because they contain concentrations of organisms close to that of primary waste water sludge. One of the companies which owns the lagoon estimates that their lagoon receives waste from 1,000 septic tanks a year. The other reports that its two lagoons combined receive an average of 75,000 gallons of septage per month. According to the Northampton County Ordinance, septic tanks must be emptied every five years. This follows the recommendation of the Chesapeake Bay Preservation Act. As yet, Accomack has not adopted this as policy and has no set standard for emptying-intervals of septic tanks. Undoubtedly with the enforcement of the Preservation Act, these lagoons will be used more heavily. In Virginia, septage was essentially unregulated prior to 1982. Now septage is subject to on-site sewage handling and disposal regulations requiring pumpers to take septage to approved facilities. Such facilities are municipal treatment plants or state-approved lagoons, which are aerobically digested by bacteria. In counties with population densities of less than 100 persons per square mile, septage can be directly applied to the land with the approval of several boards (Weigmann and Kroehler, 1988). The Eastern Shore lagoons are not required to follow the 1982 legislation because of a grandfather clause. The lagoons are not lined, and thus pose a threat to the ground water supply. In particular, one of the lagoons in Accomack County lies within the spine recharge area. As with the landfill, the location of this lagoon in this special area poses a serious threat to ground water quality as deep as the lower confined aquifer. No contamination has been documented to date, and it is speculated that sediments have lined the bottom of the lagoon (J. Green, personal communication, 1991). Review of ground water samples taken in 1985 from two monitoring wells located at the private lagoons in Accomack County revealed that as of that time there was no impact on ground water quality from these lagoons. In order to be assured that water quality beneath the site is not impacted, ground water quality monitoring should continue, and the sampling should include analysis for organic compounds. In addition, the ground water flow direction should be determined to ensure that the wells are indeed capturing recharge from the lagoons. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 3-18 I I I I I EXISTING LAND USE 4 1 1 1 1 I I I I I I I I I I SECTION 4 - EXISTING LAND USE PURPOSE The purpose of this section of the report is to appraise the existing land use conditions on the Eastern Shore of Virginia and to analyze the ways which land use distribution, controls, and other factors may have an overall effect on ground water. The use and good condition of the ground water supply is critical for the continued viability of human habitation in the region since ground water is the only source of potable water. In the buildout and nitrogen loading portion of this study, scenarios for assessing the impacts of land use development on ground water are explored. In conjunction, land use instruments which govern the development within the spine recharge area and wellhead protection areas must also be analyzed. OVERALL STATUS OF LAND USE CONTROLS Currently, both Accomack and Northampton Counties have recently revised their comprehensive land use plans (Accomack in 1989, Northampton in 1990). Each county also has a zoning ordinance, both of which are under revision. In this report, the comprehensive plans are the primary sources for general information on existing land use. Separate from the county bylaws, there are town plans and zoning ordinances for 12 incorporated towns in the region-8 in Accomack and 4 in Northampton. Two other towns, one in each county, have zoning ordinances, but no plan. Eight of these towns also have subdivision ordinances. Since the percent of overall land area of the region they affect is relatively small, they are not exan-dned separately here. Each county's comprehensive plan is designed to set development policy only, as they do not have legally enforceable land use maps. The Accomack Plan states that, "adoption of the Comprehensive Plan is only the beginning of the planning process. To derive any benefit from the plan, steps must be taken toward its implementation. The principal instruments of plan implementation are the zoning and subdivision ordinances, and sufficient staffing of the Accomack County Department of Environmental Affairs to effectively administer these ordinances" (Accomack County Comprehensive Plan, 1989, p. i4). The Northampton plan states that the "phase of the Comprehensive Plan that addresses private sector issues is the land use plan, together with the regulatory ordinances and policies adopted by local government. The Land Use Plan is the umbrella document that sets the pattern and provides overall guidance" (Northampton County Comprehensive Plan, 1990, p. 11-9). The Northampton Plan further states that it "presents a Land Use Plan for Northampton County. The Plan has been prepared in coordination with updated land development regulations to address issues with which the county is faced in the late 1980's and which will likely continue during the 1990's. Northampton County is currently considering significant changes to its existing zoning ordinance. The advisory nature of both county plans presents a conservative approach to the interpretation of Virginia Law in defining the purpose of the Comprehensive Plan and Land Use Plan. In comparison, the counties of Fairfax and Loudoun, which are facing substantial issues of growth including traffic and transportation problems and a severe strain on county public facilities, have developed comprehensive plans (particularly the land use plan and map) that are enforceable legal documents which can supersede zoning and other development regulations in many cases. In these Northern Virginia cases, the long-range impacts of future county development have been assessed according to plan projections of population, employment, land-use density and other factors to assess future county service and facility needs, funding requirements, and needed changes in other county regulatory instruments. Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 4-1 Because Eastern Shore of Virginia Plans are primarily to be carried out through the zoning and related ordinances, such as subdivision, these ordinances will be the primary focus of this section. There are other factors that affect existing land use development on the Eastern Shore. These include regulations for wells, septic systems, forestry, agriculture, mining, and stream and shore bank protection. While such regulations have been in effect for varying periods of time and have been enforced to varying degrees, many regulations are fairly recent and their effects thus far on the long-term development of existing land use is thought to be relatively slight. Therefore it is only necessary to assess these regulations in terms of their effects in the future. In addition, the recently enacted Chesapeake Bay Preservation Act is a comprehensive and potentially far-reaching instrument that can have substantial effects on future land use. Both counties have guidelines in place to comply with the Act. Potential effects of the Act on ground water are examined at the end of this chapter. EMSTING PATTERNS OF LAND USE Agricultural land under irrigation, residential land in subdivisions, and industrial land occupied by industries that are intensive water users are the most significant factors of existing land use patterns that influence ground water withdrawal on the Eastern Shore. All of these factors will be exan-dned in the context of existing land use in the region. Table 4-1 summarizes the existing distribution of land in broad categories within the region. The categories of land use as defined in the Accomack and Northampton Plans do not completely coincide, but they are close enough that a broad land use profile of the region can be assembled. The table illuminates several contrasts between the two counties: 1 ) nearly 57% of all land in the region lies in Accomack County; 2) nearly 70% of all land in agriculture and forestry uses is located in Accomack; 3) nearly 66% of all land in marshes, wetlands and tidal areas is located in Northampton; 4) nearly 78% of all residential land lies in Accomack; 5) over 96% of all industrial land lies in Accomack. Thus, the overall picture of land use in the region is one of more intense development in Accomack County, even in the land use categories often viewed as land extensive such as agriculture and woodlands. Agricultural, residential, and industrial uses could have potentially significant affects for ground water consumption in Accomack County. Within Northampton County, agricultural and residential uses are worth a closer look. Ground Water Supply Protection and Managetnent Plan for the Eastern Shore of Virginia 4-2 Table 4-1: Existing Land Use - Accomack and Northampton Category Northampton % Accomack % Total % (Acres) (Acres) (Acres) Agriculture & 87,025 37.8 198,879 65.3 285,904 53.2 Woodlands Residential 3,800 1.6 13,361 4.4 17,161 3.2 Commercial 123 0.1 407 0.1 530 0.1 Industrial 102 0.1 2,454 0.8 2,556 0.5 Institutional 715 0.3 840 0.3 4,111 0.8 Recreation 177 0.1 8,332 2.7 8,509 1.6 Marsh/Tidal 135,500 58.9 70,371 23.1 205,871 38.3 Other* 2,505 1.1 9,996 3.3 12,501 2.3 TOTAL 229,947 100.0 304,640 100.0 537,143 100.0 *In Northampton, roads and utilities are included; in Accomack, figure includes land identified as vacant, but not roads and utilities. Vacant land is not identified in Northampton. Source: Northampton and Accomack Comprehensive Plans (1990,1989) LAND USE AND OPEN SPACE REQUIREMENTS FOR WATER AND SEWER There are three general conditions under which drinking water and waste water can be provided on a building lot. In some cases there are central or "public" systems for water and sewer, including a central or common septic field for sewage disposal. In others, a central water system is available, but individual sewerage, usually a septic system, must be located on each lot. The third case is the most common on the Eastern Shore of Virginia, where both individual water from a well and individual sewerage are provided on each lot. An individual septic system, including a holding tank and drain field, can occupy about 5,000 square feet when sized for a three or four bedroom, two bath house. Setback distances are required for wells from building foundations and from the septic system, and this adds another several thousand square feet. Current subdivision regulations in Northampton require, and the Accomack Comprehensive Plan recommends, that space be available on each lot for a reserve drainfield. This adds another requirement for unobstructed open space, perhaps another 4,000 square feet. Land above septic systems cannot be used for other purposes such as plantings (excluding grass), walkways, driveways, parking areas, or any other use that would possibly result in the blockage of, or damage to, the system. Additionally, "protection areas" around wellheads are now being set up to help assure that contan-dnants will not penetrate the well and seep into the ground water below. When the requirements for wellhead protection, primary septic system and backup drainfield are taken together, there may be a need for upwards of 11,000 square feet on each lot devoted to these systems. A septic system and backup drainfield, when used in conjunction with a central water system, may still require 8 to 9,000 square feet or more. These figures should be kept in n-dnd when developable land in the two counties are examined in the following pages. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-3 EMSTING LAND USE IN ACCOMACK COUNTY Tables 4-2 and 4-3 summarize existing zoning controls in both Eastern Shore counties. Agriculture and Agricultural Districts Agriculture in Accomack County accounts for over 65% of all land use. Potential problems exist for ground water conditions in such areas from the improper application of pesticides and fertilizers, inadequate handling of animal wastes, poor methods of retaining soils, and other land-based conditions that can affect ground water through runoff of, or percolation from, surface water to ground water recharge areas. There are several conditions in the Accomack agricultural areas (A-districts) that are noteworthy. First, large amounts of such land under active crop production are irrigated. Improper irrigation accelerates the removal of soils, pesticides, fertilizers, and other matter from irrigated land. Some of the chemicals may remain dissolved in water and percolate through to the ground water. Second, the minimum lot requirement under Accomack zoning and subdivision regulations is 30,000 square feet per lot (Table 4-3). While only single fan-dly residences are pern-titted as a matter of right in the A-districts, there are no discernable restrictions on subdivisions. Thus, subdivision of land in agricultural districts into 30,000 square foot lots, is possible. Under current zoning regulations, up to 46 percent or 13,800 square feet of each lot can be covered by a primary structure. There are no lin-dtations on coverage of secondary or auxiliary structures except those established by setback requirements. Such structures could easily add another 3-4,000 square feet of impervious surface. The remaining 11-12,000 square feet of open area may be adequate for a well and septic system, but the relatively small lot size and possibility of substantial numbers of such lots close together raises the possibility of deleterious effects on the ground water. A third land condition in agricultural districts is the frequent juxtaposition of agricultural and forestry uses with areas which often have direct relationships with ground water sources. These areas can include bogs or marshy areas; exposed, sloping banks; streams or other water bodies; wellhead areas; natural springs; pits used for dry waste or garbage disposal; and septage lagoons. Housing and Residential Districts Residential uses account for slightly less than 4.5% of land uses in Accomack County, but they account for over 13,000 acres of land area. Currently, conditions in residential areas (R-districts) that could adversely affect ground water include potentially high subdivision densities, lack of sufficient space on each lot for proper wastewater disposal, and high densities of multi-fan-dly buildings on relatively small lots. There are at least three densities of single fan-dly usage permitted in the R-District. As seen in Table 4-3 if a lot has central water and either public or private sewer, the lot area requirement is 10,000 square feet. If the lot has either central water or central sewer, but not both, the lot size must be increased to at least 15,000 square feet. If the lot must accommodate both its own water and sewer systems, then it cannot be less than 20,000 square feet in size. Setback requirements mean that about 60 to 70 percent of these lots that are 10,000-12,000 square feet may not be occupied by the primary structure. However, ancillary structures, driveways and other features often found in residential areas, such as walks, trees, and other landscaping, can cut down the amount of open space available for well and septic areas. Thus, as lot size increases substantially to accommodate individual water and sewer systems, the amount of space usable to such systems may only increase marginally, if at all, and the percentage of such space relative to lot size actually decreases. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-4 Table 4-2. Imul Use Category by Zoning District, Easkm:n Short of Virginia Use Categorv Districts Actitimack Northampton A R B I BI AR R20 R11 RM MHP CN CC CW PI IL Ag./Forestry x a a e xe xe x Preserve x a a x x x x Lodge/Club x a x x x e x Rec./Private x e a x 0 e xe x x Rec./Public a x a x a xe x x Dock, Private x a a x x Dodr, Public a a a x x Single Family x x a x x x x Multi-Fan-Lily a e a x x x x x x x xe Mobile Home e e e xe xe xe x Mobile Home Park e a a x Camp/Trailer e e a e x less. Housing a a a x x Home Office x x a x x x x School Library x x x a a x e x x x Religious x x x x x x x x Cemetery x a a a Post Office x x x e x e x Other Public a a a e e x e e x x x x a x x xe xe xe xe xe x xe x x Retail Gen. e e x x x x Public Assem. a a x x x U,ili,y Restaurant e a x e x x x Hotel/ Motel/Transient e e x e e x x Industry General e a e x e e x x Ag. Processing a a e x Seafood Plant e e e x e e Sawmill a a e x x Quarrying /Conc. a a a x x Marine Comm. e e x x x x x Serv. Sta./Gar. a a x x e x Dry Ceaning/Laundry e e x x x x Build. Supply a a x x x Indoor Stor. a a a x Printing/Mach. e e x e x x x Office, General 0 e x e x x x Hospital e e x e xe Other Health a e x e xe x Funeral Home a a x e e e x Junkyard a a a e Other Outdoor 1,or. a a a x x Airport a a a e x Outdoor Adv. a a a x x x x x x x x x Other Trans. a a a e x xe x x Landfill a a a a a - any other use, review needed, e exception, review needed, x permitted, xe permitted in some areas review needed in others. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-5 Table 4-3: Zoning Lot Sizes and Open Spam Accomack and Norflumpton Counties Minitnurn Dimensions Gross Zone District Lot Size Min. Lot Size Open Space* Percent By County Sq. Ft. in Feet Sq. Ft. Open Space ACCOMACX * - Agriculture 30,000 150 x 2DO 16,200 54.00 * - Residential Central Water/Sewer 10,000 100 X 100 8,950 89.5 Cent. Water/Indiv. Sewer 15,000 100 X 150 10,450 69.7 Indiv. Water/Sewer 20,000 100 x 200 11,950 59.7 Multi-Family Central Water/Sewer Number of Units 2 12,000 100 x 120 9,550 79.6 3 14,000 100 x 140 10,150 72.5 4 15,000 100 x 150 10,450 69.7 5 16,000 100 x 160 15,750 67.2 20 31,000 100 x 310 15,750 50.8 B - Business NA NA NA N A I - Industrial NA NA NA NA BI - Barrier Island 174,240 200 x 871 84,460 48.5 NORTHAMPTON AR - Ag. Residential 43,W 125 x 348 26,400 60.6 Residential R-20 Single Family 20,000 80 x 250 12,250 61.3 R-1 1 Single Farrifly Public Water/Sewer 11,000 60 x 183 5,860 53.3 Public Water or Sewer 20,000 60 x 333 8,860 44.3 RM - Multi-Family Duplex: Public Water/Sewer 40,000 110 x 363 10,498 52.5 Indiv. Water & Sewer 50,000 110x227 11,568 46.3 Patio/Atrium 100,000 880 x 113 26,400 26.4 Townhouse 40,000 346 x 101 19,800 49.5 Multi-family, Other 25,000 140 x 179 15,250 61 MI-T - Mobile Home Park 5,000 40 x 125 4,000 80 CN - Commercial Neighborhood 15,000 100 x 150 6,840 45.6 CG - Commercial General 15,000 100 x 150 6,840 45.6 CW - Commercial Waterfront 15,000 100 x 150 4,500 30 PI - Planned Industrial 50 acres 1000 x 2178 1,506,800 69.2 IL - Industrial Limited 435W 200 x 218 27,960 64.2 IG - Industrial General 30000 150 x 200 21,070 70.2 HD - Historic District NA NA NA N A AP - Airport Protection NA NA N A NA PUD - Planned Unit Develop. NA NA NA NA FH - Flood Hazard NA NA NA NA *This figure represents the minimum open space per lot or development possible under existing yard requirements. Driveways, walks, accessory uses and other site features could further reduce this area. Conversely, not all buildings am built to these setback lines. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-6 Potentially inadequate space for water and sewer systems is also found in R-Districts where multi- family structures are allowed. Table 4-3 indicates that while two-fan-dly structures require at least 6,000 square feet each per lot, the construction of a five-fan-dly structure would effectively double the unit density. If a twenty-unit structure were constructed, the density would be doubled again, and the potential effects on ground water more pronounced. A two-unit structure would have a possible 9,550 square feet of open space for water and sewer systems. Three or more units would increase this acreage only marginally. The amount of open space per unit would actually decrease as would the percentage of such space relative to the size of lot. As with the single-fan-dly examples, other features could further reduce the space available. One anomaly present in the Accomack Subdivision Regulations is found in Section 5., Paragraphs 5.2.4-1 through 5.2.4-3. These paragraphs repeat the requirements of varying lot sizes found in the R-District. (Table 4-3). However, uniformly larger lots (15,000 square feet) are required if the area has gj1hff public water or public sewer. This seems to make sense in the case of central water and individual sewer (septic or septage) because of increased land requirements for the sewage system. However, the reverse situation would not seem to require additional lot size. Individual wells may require somewhat more area due to well location requirements, but not as much as individual sewerage. Industry, Business and Industrial/Commercial Districts Industry and commercial uses occupy less than one percent of the land in Accomack County. However, estimates of water consumption by some of the major water users in Accomack suggest that industry uses in excess of 30 percent of the ground water on a daily basis (Comprehensive Plan, 1989, p. 11-68). There is no minimum lot size in either industrial or commercial districts. While facilities with individual sewage disposal systems must have their lot sizes approved by the state health official for the county, the criteria for such approval are not clear in the Zoning Regulations. Thus, uses on one site could substantially affect uses on an adjacent site. EXISTING LAND USE IN NORTHAWTON COUNTY Table 4-3 also summarizes existing open space due to zoning controls in Northampton County. Agriculture and Agricultural Districts Agriculture and woodlands in Northampton account for almost 38 percent of all land use. Similar potential problems are associated with agriculture in Northampton County as with Accomack County. Ground water contamination may result from the activities of pesticide and fertilizer applications, problems with soil erosion from improper tillage or forestry harvesting, and leaking septic or cesspool facilities. As in Accomack County, large portions of agricultural land in Northampton are irrigated, and it is estimated that 19-23 percent of all agricultural land in Northampton is currently under irrigation. Residential zones in Northampton agricultural areas offer larger n-dnimum open space potentials than those in Accomack. The minimum lot size for residential development in Northampton agricultural districts (AR) is one acre (Table 4-3). Using minimum frontage and setback requirements, it may be ascertained that 26,400 square feet of each one acre lot not fronting on water or Route 13 would be available for open space. This compares to a figure of 16,200 square feet in the A Districts of Accomack. As in Accomack, this open space may be covered by outbuildings, walks, driveways, or other features that further restrict the space used for wells or septic systems. Again, Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 4-7 the result of these relatively small areas introduces the potential for forcing wells and sewerage to co-exist in somewhat restricted areas. The land use categories that cover the largest portion of Northampton are marsh/tidal areas; these occupy almost 59 percent of the county, over 135,000 acres. Agriculture and woodlands take up about 38 percent. Inevitably these two uses are intertwined in many parts of the county, in that water from wetland areas associated with dammed creeks may be used for irrigation purposes, and crops may have been planted within drained marsh areas. Where this happens there is the potential for direct contamination of ground water by agricultural or forestry practices. Housing and Residential Districts Residential land use in Northampton occupies a much smaller land area in Northampton than in Accomack-3,800 acres versus 13,361 acres respectively. Residential zoning in Northampton, however, is somewhat more diverse than in Accomack. While the single residential district used in Accomack can accommodate single family and multifan-dly housing in several configurations, the Northampton R Districts are more detailed in the number and type of housing units permitted and the conditions under which such units are permitted given types of water and sewer systems. More importantly for ground water protection, Northampton single family districts often require larger lots for single family houses for either central, combined or individual water/sewer systems. For example, central water and individual sewer in Northampton require a lot size of 20,000 square feet. In Accomack, the corresponding lot size would be 15,000 square feet. However, in Northampton County the primary building coverage can occupy nearly 66 percent of the lot, leaving only 8,860 square feet or less for a well and sewer system. In Accomack, the building coverage is restricted to about 30 percent, leaving over 10,400 square feet for landscaping, well, and sewer space. Current zoning in Northampton County provides for a Residential Multi-family or "RM" District. Duplex, patio/atrium, townhouse and apartment structures are permitted in this district. Of these, the patio/atrium option can occupy at least 73 percent of the lot area, based on a configuration incorporating a n-dnimum of 10 dwelling units. The remaining 2,640 square feet per unit would be very crowded should individual septic systems be installed. Additional landscape features such as driveways, parking areas and plantings would further reduce the space for septic systems. It is typical that this type of unit is built to the lot line on at least two sides, and thus the close proxin-dty of individual septic systems is almost guaranteed. Given the current zoning, townhouse units have the potential to be even more crowded than the multi-family residential units. Individual units could have just slightly over 1,500 square feet for septic systems, and multifan-dly apartment units can have about 3,200 square feet of open space per unit. These units can also be in tight configurations raising some of the same concerns expressed about the atrium units. At least 10 parking spaces must be provided for the n-dnimum 5 units, which would occupy about 560 feet per unit. Thus the space available for septic systems would be reduced to about 2,600 square feet per unit. Additional landscape features could reduce this figure even further. Industry, Business and Industrial/Commercial Districts Industrial and commercial uses occupy about 225 acres or less than one-fifth of one percent of all land in the county. While such minimal areas are not likely to have major impacts on ground water supplies, several features of the zoning requirements for such areas are worth noting. For example, in any commercial district, CN, CG, or CW, the building and parking spaces can occupy over 50 percent of any development parcel. The amount of open space left for the well and septic system- Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 4-8 6,800 square feet in the configuration adopted for the assumption used here-may be minimal given other features, such as trash disposal, landscaping and parking and circulation, that can occupy the site. In the CW or Commercial Waterfront District, there are no open areas required, thus allowing for a particularly crowded water and sewage system for those sites adjacent to water bodies. Other Uses Northampton has a Planned Unit Development District in which 75 percent of the land area may be occupied by lots, buildings, streets and off-street parking. If such lots were developed as townhouse or atrium developments, then on-lot space for septic systems would be extremely limited. The 150 units or lots that would be permitted under the minimum development size of 15 acres and the maximum density of 10 dwelling units per acre for RM zoning could result in a substantial demand for a central, land based sewage disposal system. Of the 25 percent of the development left in open space, about 3.75 acres, much or most could be occupied by such a system. By far the largest land use in Northampton County is that occupied by marsh or tidal areas. However, there is no specific zone district to treat such land. The Northampton Comprehensive Plan addresses the need for special treatment of tidal wetlands, barrier islands, and wetlands bordering on Bay side creeks and their branches. Additionally, in the Zoning Regulations, the use of wetlands in calculating developable areas on development parcels is excluded. However, there appears to be no specific protection plan for non-tidal wetlands, which are important for the recharge of ground water supplies. Table 4-2 sets out detailed use categories and establishes their status in each zoning district for the two counties. In general, Accomack County appears to have a less restrictive, more inclusive ordinance. As evident in the table, nearly every land use is either permitted or excepted in agricultural, residential, and business districts. Comparatively, industrial zoning is highly restrictive, allowing only industrial and utility uses, with no exceptions allowed for other non- residential or residential uses. Northampton's approach to zoning is quite the opposite. The county has an agricultural district, four residential districts, three business or commercial districts, and three industrial districts. Northampton also has four "overlay zones": historic, airport protection, planned unit development, and flood hazard, which can be used with the plan review to modify the underlying zones for the purposes of each overlay. In addition, Northampton has further front yard setbacks required in its Zoning Regulations along U.S. Route 13 that would increase the area space per lot. This is designated as "Highway Protection" in the Comprehensive Plan. Northampton's zoning is substantially restrictive. For example, some agricultural uses are permitted only with special exceptions in the Agricultural /Residential District. Few industrial uses, even sawmills and agricultural processing plants, are permitted in the Agriculture/ Residential District. In residential districts, many public facilities are either prohibited or only permitted with a special exception. Some anomalies do exist. For example, in the Residential Multi-family District, usually the least restrictive of any residential zone, only religious uses are permitted as a matter of right. Schools, libraries and some other public facilities are permitted only with special exceptions. Post offices are prohibited, as they are in AR Districts. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-9 LAND USE CONTROLS AND EFFECTS ON GROUND WATER The following chart summarizes land uses, the categories that may have particularly substantial effects on ground water, the general nature of those effects, and the status of those land use categories under present zoning or other review. Table 4-4: Analysis of Land Use Effects on Ground Water Supplies LAND USE/ NATURE OF GROUND- REVIEW USECATEGORY WATER EFFECT STATUS AUiculture Cropping Pesticides, fertilizers may penetrate Matter of right (MOR) to water table and ground water in both counties.* (see last page of table) Irrigation draws substantial amounts of Most withdrawals water in dry periods. are not metered. Grazing Animal wastes may contaminate water Review under Nor- table and ground water. thampton Zoning only*. Forestry Pesticides may penetrate to ground water; Matter of right (MOR) in cutting may enhance erosion. both counties. Residential Single Family Some lots may be too small to comfortably Matter of right, but accommodate wells and/or septic systems, VA health review is and drainfield reserve areas. required. Mobile Homes Mobile Home Parks must have enough Special exception or land per unit to accommodate well and/or health depart review; septic system. both counties. Multi-Family As for single family. Matter of right, but VA health review is required. Utility This category can include public and Matter of right in private water and sewage operators that Accomack A, R and can withdraw large amounts of water and I zones. Review in B zone. dispose of large amounts of waste water. MOR in Northampton The methods, condition of equipment, and AR, CG, PI and IL conservation practices of the operator can zones. Possible review affect ground water supplies. in others. VA Water Control Board requires permit for large withdrawals, discharges. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-10 Table 4-4. Analysis of Land Use Effects on Ground Water Supplies (Continued) Retail Restaurant Restaurants can be large water users and Accomack - reviewed in often, discharge substantial amounts of A,R zones. MOR in B. waste water. Northampton - MOR in C zones. Reviewed by VA Board of Health for minimum water flow. Hotel, Motel, Can be large water user and waste water Accomack - reviewed in Other Transient discharger. Especially in combination A, R zones. MOR in B. Facilities with a restaurant. Northampton - reviewed in AR, R20 zones. MOR in CG, CW. Indusfty General A variety of industries including research Accomack - MOR in Industry labs, production facilities, and service I zone; Reviewed in A, industries-especially food and bottling Rand B zones. Nor- industries--can be major water users and thampton - MOR in PI, IL can discharge toxic wastes, depending on and IG zones. Excep- their processes. tion in CG and CW zones. Major water withdrawals subject to VA State Water Con- trol Board approval. Ag. Processing, These industries usually use large amounts Accomack - See above. Seafood Plant of water for cleaning the product and Northampton - Excep- usually discharge waste water filled with tion in IG for Ag.: in food wastes. CW, IG for seafood. Sawmill, Quarry- Sawmills may use water for cooling and Accomack - MOR in ing, Concrete Mix discharge waste pulp; quarries sometimes L Exception in A, R, act as "drain holes" for surrounding area B. Northampton - Saw- contaminants; concrete plants use sub- mill MOR in IG; stantial water and discharge waste filled Quarry, Conc. MOR in with lime and toxics. P1. Exception in IG. Marine Commer., These uses often discharge or leak petro- Accomack - Marine Service Station, leum products to the ground. Additionally, Serv. Stn. MOR in B,I. Airport, Junk yard battery acid and other by-products may Airport, junk yard leak from junk yards. exception in A,R, B Nor- thampton. Marine MOR in AR, CW, PI and IG. Serv. Stn. MOR in CG, Junk yard MOR in IG exception in CG; Airport MOR in IG, exception in AR. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-11 Table 4-4: Analysis of Land Use Effects on Ground Water Supplies (Continued) Dry Cleaning, These uses can discharge distillates and Accomack - Dry Clean Building Sup. and other toxics to land areas. Bldg. Supply Exception in Other Storage A, R; Other Stor. MOR in 1, Exception in A, R, B. Northampton - Dry Clean MOR in CN, CG; Bldg. Supply MOR in IL. Indoor Stor. MOR in IG; Outdoor Stor. MOR in IL, IG. Landfill Landfills have been shown to be potent- Accomack - Exception ially major polluters of ground water sources. only in A, R and B Substantial amounts of toxic materials zones. Northampton have been-and are-dumped in these Evidently pro- locations and, depending on ground soil hibited in all zones. and geology, may leach these toxics to aquifer. *Farm Use Only Generally, where the above uses are a matter of right, that is, where they can proceed to construction without review by government authorities and other advisers qualified to assess their effects on soil and ground water conditions, they may pose a distinct threat to ground water supplies. Degradation can occur either from overuse or contamination of ground water aquifers, in areas where soil and geological conditions indicate a high susceptibility. In cases where potentially harmful uses are reviewed, the review process may need strengthening to assure that such reviews are accomplished beyond that of the normal site plan or other process. After the review and possibly the remediation, the uses which could have highly adverse long and short- term effects should be monitored on a periodic basis to be sure that the remediation remains in place. A field survey and engineering /planning studies should be conducted to determine what existing land uses are potentially threatening to ground water and soil conditions so that remedial measures may be carried out. SUBDIVISION OF LAND Both counties have subdivision ordinances in place. In Accomack, final plats must be approved by the county and State Highway Department for public streets and drainage, and by the State Health Department for water and sewer facilities. Health and public road improvements must be secured by cash or a bond. In addition, trailer parks must also be approved by the State Bureau of Tourism. Accomack's subdivision ordinances also states that the State Health Department can order lot sizes larger than the n-dnimum sizes established in the Zoning and Subdivision Ordinances if "factors of drainage, soil condition, population density or other conditions can cause potential health problems." Additional open space requirements are set out in the ordinance for buffering trailer parks from surrounding property. Lots larger than 3 acres in size are excluded from subdivision requirements under the Subdivision Ordinance in Accomack County. All final subdivision plats must be prepared by a state-registered engineer or surveyor. There is currently no Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-12 requirement for drainfields reserved for septic systems in Accomack, although that is suggested in the County Comprehensive plan. In Northampton, divisions of land are apparently excluded from subdivision review if the resultant lots are 5 acres or greater in size and if a single subdivision of a lot or parcel is made for the purpose of sale or gift to a member of the immediate family of the property owner. If the subdivision has 26 or more lots created, it is considered a major subdivision. A major subdivision must be reviewed by the State Highway Department, the State Health Officer, each incorporated town within 2 miles of the project, each utility company providing service to the project, and all abutting property owners and other agencies the Planning Director deems appropriate. The State Highway and Health Department comments must be received prior to review and action by the County Planning Commission. Plans must be prepared by a state-licensed surveyor or engineer. All major subdivisions must have a central water system in Northampton. All proposed improvements are bonded for implementation by the owner or his/her agent. The procedure for approval of minor subdivisions, those with 25 lots or less and with lot areas of less than five acres, is the same as that of major subdivisions except that final approval can be granted by the Planning Director rather than the Planning Commission. Lots in Northampton that use private, individual wells and septic systems must provide an additional, non-overlapping replacement drainfield site. No such site is required if a well is not located on the lot. Additionally, wetlands cannot be separated from a lot. All wetlands must be incorporated into an adjoining lot where they are counted against the lot size for purposes of establishing n-dnimum lot area and for calculating buildable portions of the lot. This can have the effect of allowing building and development adjacent to wetlands on the subject lot. It also removes the wetland as a special area separated from development and subject to special protection. Subdivisions in Accomack County There have been over 160 subdivisions in Accomack County (Table 4-5) approved between 1972 and 1990. Of these 15 are campgrounds or other seasonal developments. These 15 subdivisions have 4,193 lots of which nearly 66 percent, or 2,765, currently have structures or trailers on them. Another 44 subdivisions are trailer parks containing 2,813 lots. Nearly 56 percent, or 1,563, of these are occupied by units. The remaining 113 subdivisions are primarily occupied by single-fan-dly houses ranging in size from 2 to 5 bedrooms. There are a few duplexes, but these units are primarily 3-bedroom, 2-bath dwellings. Of the approximately 8,500 lots in these subdivisions, only 19 percent or 1,627 are currently improved with structures. Table 4-5: Subdivision Development in Accomack County, 1972-1990 Type of Number in Number of Number % Subdivision County Lots Improved Improved Campground or 15 4,193 2,765 65.9 Seasonal /Vacation Trailer Parks 44 2,813 1,563 55.6 Single or Multi-Fan-dly 104 8,449 1,627 19.3 Total Subdivisions 163 15A55 5955 38.5 Source:Accomack County Department of Environmental Affairs, Zoning Administrator's Office, April 1991. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-13 Of the 163 subdivisions referenced above, at least 60 have central water systems. The remainder have individual wells on each lot. Over 100 subdivisions have both individual water and septic on each lot. Eleven subdivisions have central holding tanks for sewage that are pumped out periodically. The septage is then disposed of in lagoons. One subdivision has both central water and a central drainfield for wastewater disposal. Subdivisions in Northampton County There were about 150 subdivisions approved in Northampton between 1974 and early 1991. Between 1970 and 1980 appro)dmately 320 trailers and 602 other year-round housing units were added to the e)dsting housing stock. If one assumes a similar proportion of development in the subdivisions recorded, the results would be as those set out in Table 4-6. The number of lots recorded in these subdivisions total 2,016. Of these, it is surmised that about 1,154 have been improved. It is further surmised that 542 of the lots are improved with trailers, while 322 are improved with single family houses. Accordingly, an additional 290 camping and seasonal lots would be currently active. Table 4-6: Subdivision Development in Northampton County Typeof Number Number Number % Subdivision in County of Lots Improved Improved Campground or 49* 431* 290* 67.3 Seasonal/ Vacation Trailer Parks 34* 673* 542* 80.3 Single or Multi-Family 68* 912* 322* 35.3 Total Subdivisions 151 2,016 1354 57.2 Source: *Derived figures Director, Planning and Zoning, Northampton County; Northampton County Comprehensive Plan and Plan Background, July 1989. It is thought by county planners that all of these subdivisions are served by individual water and sewer. THE CHESAPEAKE BAY PROGRAM ON THE EASTERN SHORE OF VIRGINIA Introduction The Virginia State Chesapeake Bay Preservation Act (CBPA) of 1988 - Chapter 21 of the Virginia State Code, Sections 10.1-2100 through 10.1-2115 - sets out requirements for all local governments in Tidewater Virginia to develop land use regulations based on the state code in order to protect water quality in the Chesapeake Bay and its tributaries. Each locality will incorporate the new regulations into their comprehensive plan, zoning bylaws, subdivision plans, and other land development ordinances. Both counties on the Eastern Shore and the self-governing towns are required to prepare such regulations. Under the CBPA where a town does not have planning, zoning, or other such regulations, or chooses not to prepare regulations on its own, it may act to be subject to the county program. Basic Approach The state program is overseen by the Chesapeake Bay Local Assistance Board. The Board is comprised of nine members appointed by the Governor. The Board is staffed by the Local Assistance Department, a state agency that provides technical support to the Board and technical advice and Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-14 assistance to the local governments. The Board has developed regulations for the designation of Chesapeake Bay Preservation Areas and for land use management to accomplish the aims of the legislation in those areas. It also provides financial and technical assistance to local governments where required. The Board must approve all locally prepared plans and assure compliance of each local government with the Act, but is not responsible for specific decisions about particular sites in the Preservation Areas. Those decisions will continue to be made by the local government based on the locally prepared regulations. The Chesapeake Bay Preservation Area (CBPA) contains three general land categories: the Resource Protection Area (RPA); the Resource Management Area (RMA); and the Intensely Developed Area (IDA). Very generally, an RPA is land at or near the shore of the Bay or tributary which can protect water quality but, if damaged by development or other disturbance, can degrade water quality. These areas include tidal wetlands, nearby non-tidal wetlands, tidal shores and other lands whose disturbance would harm the area. An RPA must contain a buffer area along the landward side measured from the landward face of the above features. Only redevelopment and new, water-dependent uses can be developed in an RPA. An RMA is land which protects the RPA. Development and other land disturbance in these areas can have adverse effects on the RPA and ultimately degrade water quality. Floodplains, steep slopes, soils susceptible to erosion, soils with a high degree of permeability, non-contiguous non- tidal wetlands and lands required to protect water quality are to be included as RMA's. In some cases the entire drainage basin of a water body may be designated as an RMA boundary. RMA's must be designated landward of RPA's. Any use pern-dtted by local zoning can be developed in an RMA, subject to certain performance criteria. An IDA is an area that, due to previous development, may be located in an RPA or RMA. Redevelopment and infill development can take place in these areas where little natural land area remains. An IDA must be so designated if an area has more than 50 percent of its surfaces in impervious materials, or is served by public water and sewer, or has a housing density of 4 or more dwellings per acre. State regulations were adopted in September, 1989 and became effective October 1 of that year. Lots recorded after the effective date are subject to the regulations. However, local governments may allow modification of the buffer up to 50 feet, and may not require a reserve drainfield (one of the regulatory requirements) depending on the local program developed. All local governments are to have their adopted local regulatory programs in place by November 19, 1991. Northampton's program was incorporated into its Draft Comprehensive Plan in late 1990 and was drafted as an overlay district for the zoning ordinance. Accomack's program was also drafted as a zoning overlay district and is currently being assessed by the County Board of Supervisors. Implications for Ground Water Protection All locally prepared programs for Chesapeake Bay Preservation Areas (CBPA's) must meet general performance criteria. These criteria are designed primarily to reduce nonpoint source pollution of surface water and to protect sensitive lands from disturbance. The criteria include: 1 ) preservation of natural vegetation; 2) restricting disturbance of land; 3) restricting impervious cover; 4) controlling soil erosion-especially in areas of susceptible soils and during land clearing construction and other land-disturbing activities, such as tillage; 5) controlling the volume and quality of stormwater runoff; Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-15 6) controlling the overflow and leaching of septage from tanks and drainfields by regular, mandatory pumping; 7) providing for reserve drainfield capacity for septic systems that equals the treatment capacity of the primary drainfield; 8) requiring site plan review and the preparation of various studies such as a water quality impact assessment and a site plan review document; 9) control of stormwater quality in agricultural and forestal areas within or adjacent to the RPA. Of the above performance criteria, all relate to the ultimate use and condition of ground water. However, several have the potential for more directly affecting ground water withdrawals and quality. Overflow and leaching of septic drainfields and tanks, especially when they are in close proxin-tity to wells, can cause both immediate and long term effects on drinking water. The inclusion of provisions for pumping out systems every five years is a start to controlling this overflow and leaching. The requirement of provisions for back-up drainfields in areas that do not overlap the original facility provides a longer-term solution to the problem. Control of storm water quality in agricultural and forestal areas is also important to ground water quality. This performance criteria is primarily directed toward the protection of surface water from pollution by soil erosion, pesticides and fertilizers. These problems also can affect ground water, but not simply through storm water runoff. The large amount of water used for irrigating crops in the area can carry these pollutants into the soil as well. Where surface soils have a high degree of porosity, especially where the subsurface soils are not clay or clay loam, chen-dcal compounds used in agriculture and silviculture can be transmitted to ground water fairly quickly. Where wells and watering ponds draw from this contan-dnated ground water, especially in the upper aquifer, deleterious effects on humans and animals from consumption can be expected to be noticed relatively quickly. Another area where there may be beneficial effects on ground water quality is in the attention of the Act and local programs to protect wetlands. Depending on substrata conditions, wetlands can act as large filtration systems for broad areas that drain surface waters to the wetland. This water may then penetrate to ground water aquifers at a faster rate than is possible when water seeps into surrounding upland soils. The process of filtering out harmful substances is enhanced where wetlands and marshy areas are protected by buffers of natural vegetation. Such a buffer zone is called for in the Act and its attendant regulations. The capacity of the buffer to adsorb pollutants is further increased where these substances are further controlled through agricultural best management practices and erosion control plans. In addition to the performance criteria set out in the Act, state agencies have called for further performance standards. Briefly, these are as follows: 1 ) prevent any increase in pollution from new development; 2) achieve a 10% reduction in pollution from redevelopment; 3) achieve a 40% reduction in pollution from agriculture; 4) limit any land disturbance to 60% of a site; 5) preserve vegetation and limit impervious coverage; 6) require a soil erosion and sediment control permit; 7) stormwater from new development must be limited to pre-development levels; 8) federal and state wetlands permits are needed before grading and clearing; Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-16 9) agriculture requires a Conservative Plan of Best Management Practices approved by the Soil & Water Conservation District and put in place by 1995. There are several points worth noting. The limitation of development of a site to 60 percent of the total area is commendable. However, as can be seen in the studies done for existing land use (Table 4-3 ), some zone districts already limit building area to substantially less than this figure. There may be substantial problems of pervious areas sufficient for individual well and septic systems, as well as for any requirements for reserve drainfields, given such figures and the size of lots. There are some differences in the CBPA regulations drafted by the two Eastern Shore counties. For example, Northampton will require a Minor Water Quality Assessment of a proposed action if the action disturbs less than 10,000 square feet of land. For Accomack, the same figure is 5,000 square feet. In each draft there is considerable attention paid to requirements for RPA's, but less definition to the requirements for RMA's. Requirements for IDA's are not included in either county's draft. Some selected modifications of the current regulations shall be made to increase the potential for ground water protection. Attention would have to be paid to space requirements for drainfields, impervious surfaces, and developments adjacent to the buffer areas. Protection of wellhead areas is one open space requirement that could be added, especially if the type of relationship between underground aquifers and surface water bodies can be identified. SUMMARY OF LAND USE ON THE EASTERN SHORE Both Accomack and Northampton Counties are currently revising their zoning based upon recently completed comprehensive plans, and the need to comply with the Chesapeake Bay Act. The pattern of land use on the Eastern Shore has been very stable over the past. In summary, nearly 70% of all land in agriculture and forestry uses is located in Accomack; nearly 66% of all land in marshes, wetlands, and tidal areas is located in Northampton; nearly 78% of all residential land lies in Accomack; over 96% of all industrial land lies in Accomack. Thus, the overall picture of land use in the region is one of more intense development in Accomack County, even in the land use categories often viewed as land extensive such as agriculture and woodlands. Agricultural, residential, and industrial uses could have potentially significant affects for ground water onsumption and water quality in Accomack County. Northampton County has the majority of its land in marsh and wetlands, however, development densities could be quite high along the center c of the county, where the ground water is recharged. Many of the land uses are allowed by right, meaning that permits and reviews by each county are not required to determine if the development will have an impact on ground water use or quality. In cases where potentially harmful uses are reviewed, the review process may need strengthening to assure that such reviews are accomplished beyond that of the normal site plan or other process. After the review, the uses which could have highly adverse long and short-term effects should be monitored on a periodic basis to be sure that the ground water quality is not affected. Both counties have a significant number of approved subdivisions with a high percentage of undeveloped lots. Of the 15,455 approved lots between 1972 and 1990 in Accomack County, only 39% have structures. In Northampton County 2,016 lots were approved during the same time period and 57% are improved with structures. This indicates that there is a significant potential to increase the number of housing units, population, water needs, and wastewater disposal needs without additional approvals required. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-17 The Chesapeake Bay Act once implemented in both counties, will help to control negative ground water quality impacts from existing and future development with the requirements for periodic pumping of septic systems, leach field reserve area requirements, site plan review, restrictions on amounts of impervious areas on building lots, stormwater quality management considerations, and the protection of valuable wetlands. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 4-18 I I I I I DELINEATION OF GROUND WATER SUPPLY MANAGEMENT AREAS 1 5 I I I I I I I I I I I I I SECTION 5: DELINEATION OF GROUND WATER SUPPLY MANAGEMENT AREAS INTRODUCTION HWH approached the issue of protection of the ground water of the Eastern Shore by first examining the geologic and hydrologic conditions of the region, drawing upon existing technical literature. Appropriate criteria for aquifer and wellhead protection were explored, utilizing accepted EPA- approved criteria coupled with the hydrogeologic realities of the area. After appropriate criteria were selected, a methodology was determined and implemented to map the protection zones. SELECTION OF GROUND WATER PROTECTION CRITERIA The three-dimensional character of the ground water flow system to the confined aquifer governed the choice of the aquifer and wellhead protection area criteria. Initially, a criterion of time of travel (TOT) was evaluated. With TOT, a distance is calculated from the well or wellfield that corresponds to the amount of time it would take a particle of water (or contan-dnant) to move to the supply source within a designated threshold (10-year TOT, 25-year TOT, etc.). TOT is an extremely effective criteria in some hydrogeologic environments, particularly in unconfined aquifers in which the time it takes precipitation to recharge the saturated zone is quite short. In that situation, recharge of water is assumed to follow a piston-like pattern of flow downward through the unsaturated zones in a relatively short time frame. TOT distance thresholds are then based on the time of travel of a particle of water within the saturated zone, moving horizontally with the average velocity of the ground water under pumping conditions. On the Eastern Shore the character of ground water flow assumes more of a three-dimensional rather than a two-dimensional nature. To obtain an accurate TOT calculation for a given well in a confined system would have to account for the time taken for recharge water to pass through the unsaturated zone, the time it takes to move both vertically and horizontally within the overlying unconfined aquifer to the uppermost confining layer, the time it takes to move through that confining layer and the time it takes to move horizontally to a well screened in the confined aquifer. When a three layer system such as the Yorktown-Eastover aquifer is considered, the problems of determining TOT become extremely difficult to solve with any degree of certainty. The data requirements and qualifying assumptions to detern-tine the length of time it would take to move through such a complex pathway is extensive; TOT is not an appropriate protection criterion in this hydrogeologic environment. Criteria were selected for aquifer and wellhead protection based upon the unique hydrogeologic conditions found on the Eastern Shore. The conceptual model indicates that the recharge area to the most important aquifer (the Yorktown-Eastover aquifer) lies along the center of the peninsula. Accordingly, protection criteria were determined to address this particular situation. Radial distance was used for Zone 1, while hydrogeologic flow boundaries were used for Zones 2 and 3. Each ground water supply management area is explained below along with the method used to map the protection zones. Zone I Criteria: 200-foot radial distance around a well. Rationale: The need for a protective zone immediately around a well has more to do with human error than to hydrogeologic conditions. This zone is employed to maintain an area Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 5-1 around the well to prevent potential contaminants from moving into the aquifer via a poorly constructed or faulty annular sea] at the well. Wells that are poorly built or are old may lack the concrete or bentonite clay seal designed to prevent leakage from the surface down along the well casing into the aquifer. In addition, properly constructed seals may also break down over time and create a pathway for water an contaminants to flow into the well. A 200-foot radius around each well where virtually all activity is banned offers a measure of protection against accidental spills. Method: The radial distance is established by drawing a scaled circle around the well on a map. Zone 2 - Spine Recharge Area Criteria: Hydrogeologic boundaries based on recharge areas. Rationale: The conceptual model of the hydrogeology of the Eastern Shore indicates that the primary recharge area for the Yorktown-Eastover aquifer is located along the center of the peninsula. Assuming that precipitation falling on the surface of the Eastern Shore follows the flowpaths displayed in Figures 2-6 and 2-7, water falling along the center will penetrate vertically through the confining layer and recharge the confined aquifer. Recharge to the unconfined aquifer (the Columbia) has been estimated at between 12 and 26 inches per year (see below and Appendix E ). Recharge through the uppermost confining layer to the Yorktown-Eastover is much slower, governed by the low permeability of the confining clays and silts. That recharge rate is estimated at only about 0.10 feet per year (see below and Appendix E). Using the principle of conservation of mass, the amount of water that seeps through the uppermost confining layer to a pumping well at a low recharge rate over a large area must be balanced by an equal volume of water that recharges the unconfined aquifer at a higher rate. The volumes of water will be the same, but the recharge rates and the area required will differ. The land surface from which recharge flows into the unconfined aquifer is much smaller that the area through which recharge flows into the confined aquifer. Optimally, a full three- dimensional ground water flow model that accounts for the various differing permeabilities and thicknesses would be used to determine the recharge areas in the unconfined and confined aquifer and use particle tracking to back-track the starting points for water particles that are discharged by the pumping wells. That modelled contributing area would then be a logical choice for a protection zone. Without such a sophisticated model, a simpler solution was derived. Using a moderately conservative recharge rate of 9 inches per year for the Columbia aquifer, the amount of area within each of five areas (described below) to produce the permitted volume discharged was determined. That area was then divided equally on either side of the peninsula to form Zone 2. For this study, average values were used for recharge across the entire study area. Once the USGS model is available (see page 64), aquifer properties can be varied, and the model rerun. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 5-2 Method: The largest users of ground water on the Eastern Shore were located and mapped. This group of twenty-six wells or wellfields (Appendix E) accounts for most of the total ground water discharge permitted on the Eastern Shore. The drawdown of the pumping wells was modelled analytically using a standard ground water solution to the flow equation, the Cooper-Jacob method. The individual drawdowns were then added to model the interference effects from neighboring wells throughout the Eastern Shore. The area of the peninsula was divided into five regions based on the grouping of wells, the amount of permitted pumpage and the contributing areas defined by contour mapping of the modelled drawdowns (Figure 5-1). The protection zone for each of the five areas was determined on the basis of recharge. The total amount of permitted pumping was determined for each area. The amount of land area required to balance that volume of pumping with a 9 in/yr recharge rate was calculated. The 9 inches was chosen as a conservative value to account for drought years. Since the recharge area was determined to be located along the center of the peninsula, the length of the spine was measured in each zone of contribution, and the width of the protection zone determined by dividing the recharge area necessary by the length of the spine available. This width ranges from 1,530 feet to 4,660 feet but, to remain conservative, a larger 5,000-foot strip (2,500 feet on each side) was plotted along the spine throughout the entire peninsula (Figure 5- 2). The 5,000-foot strip represents the size of surface area that contributes water to the wells in the Yorktown-Eastover aquifer. As the recharge flows downward in the Columbia aquifer it also moves horizontally towards the coasts (see Figure 2-7). The contributing area at the base of the Columbia has therefore grown wider. The transfer rate from the Columbia to the Yorktown-Eastover aquifers is then lower in order to maintain the same volume of water passing through the confining unit. Zone 3 - Wellhead Protection Areas Criteria: Hydrogeologic boundaries using contributing areas of flow. Rationale: The moderate to low transn-dssivi ties found within the Yorktown-Eastover aquifer coupled with high levels of permitted discharge on the part of a number of major users creates substantial drawdowns in individual wells. These drawdowns interfere with one another, and since individual cones of depression are additive, the interference patterns serve to exacerbate the problems of excessive water level drop. Pumping from the confined Yorktown-Eastover aquifer produces a gradient on the overlying confining unit and the unconfined Columbia aquifer. In those areas, patterns of recharge and downward vertical flow occurring primarily along the central spine will be modified to some extent by the increased gradients, particularly where the confining unit possesses relatively high hydraulic conductivity or where the clays and silts are missing altogether. Those conditions could apply especially where the documented paleochannels cross the Eastern Shore peninsula. In such locales, recharge will occur from areas other than the central spine under conditions of substantially higher gradients created by pumping. To address this issue on a peninsula-wide basis, Zone 3 is proposed. Zone 3, based on ground water divides created by the superpositions of pumping patterns upon the ambient potentiometric surface, covers virtually the entire peninsula. The Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 5-3 OCEAN A TIC 0 ts -10 .20 .5 .2D -25 -20 5 -25 .20 lei 0 %5 .10 .5 CHESAPEAKE -10- POTENTICIMETRIC SURFACE CONTOUR I LODD 0 22,000 33.ODO scale (loot) 1,4 '000' ATLANTIC OCEAN WPA-A WPA-B WPA-C WPA-D WPA-E Ilk. r ...... .... ............... B W( Cv4ES4PE4V(r WELLHEAD PROTECTION AREA (maximum permitted pumping rates) WELLHEAD PROTECTION AREA (existing pumping fates) SPINE RECHARGE AREA 11.000 0 22.000 33.000 scale (lest) 5-5 . I employment of such a zone serves to establish formally how widespread the impact of ground water withdrawals has been on the hydrogeologic system of the Eastern Shore. Creating a zone of protection at the scale of Zone 3 re-emphasizes the dependence of the area on its ground water supply and how activities throughout the region, not simply along the central corridor, affect the quality and quantity of ground water. Method: The results of the analytical modelling to determine the amount of drawdown caused by pumping the major producing wells on the Eastern Shore were combined with a map of the pre-pumping conditions taken from the numerical flow modelling conducted by Bal, 1977. The resultant water level surface was then analyzed to ascertain ground water divides that form the boundaries to the zones of contribution to the Eastern Shore. See Figure 5-1 for the potentiometric map for permitted pumping rates. The zones of contribution constitute Zone 3 (Figure 5-2). PHYSICAL DESCRIPTION OF EACH WELLHEAD PROTECTION AREA The Wellhead Protection Areas (WPA's, Zone 3 ground water supply management areas), reflect the contributing areas to existing wells under permitted pumping rates. Below is a breakdown of certain activities within each WPA, along with a general geographical description. Please refer to Figure 5-2 for the location of each WPA. Wellhead Protection Area A - Chincoteague Area Area: 27,000 acres Number of Wells: 13 Number of VPDES dischargers: 17 Landfills: 2 closed Lagoons: none Of the WPA's, this wellhead protection area covers the least extent of upland. It includes Chincoteague Island to the east, Captain's Cove to the north, Oak Hall to the south, and includes the town of New Church and the NASA Wallops Station. The old northern landfill in Accomack County (now closed) is located within this area, and apparently there is a closed landfill on Chincoteague. Large wells serve Captain's Cove, the Town of Chincoteague, NASA Wallops Main Station, and New Church Energy Association. These facilities also have discharge permits to dispose of liquid wastes in the area. Water taken from the tap at Stoney Point Decoys, NASA Wallops Flight Center, and NASA Wallops Island have all tested above 5 mg/l for nitrate- nitrogen, with readings ranging from 7.11 to 11.5 mg/l. Wellhead Protection Area B - Holly Farms (Tyson Foods) Area Area: 43,000 acres Number of Wells: 9 Number of VPDES dischargers: 6 Landfills: 1 Lagoons: 1 The towns of Withams, Hallwood, Nelsonia, and most of Wallops Island are located in this wellhead protection area. To the east, it extends into the Atlantic Ocean, and to the west it reaches as far as Route 698 near the Saxis area. This wellhead protection area contains the Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 5-6 greatest visible contamination threat. Directly on the spine recharge area is the Northern Landfill for Accomack County and one of the two Bundick septage lagoons, which is unlined. Any contan-driation which reaches the ground water within this recharge area could eventually contan-driate the Yorktown-Eastover aquifers. Water withdrawers and septage dischargers located in this area are Holly Farms, which is second to Perdue in its pern-dtted water withdrawal rate, Taylor Packing Company, and the NASA Wallops Island facility. The Atlantic Fire House is the only known facility in WPA B to have nitrate-nitrogen levels above a negligible amount; a sample taken in 1981 measured 5 mg/l. Wellhead Protection Area C - Perdue Area Area: 76,000 acres Number of Wells: 15 Number of VPDES dischargers: 7 Landfills:none Lagoons: 1 This is the contributing area created by pumping from Perdue, Byrd Foods, the towns of Onancock and Parksley, and the Accomack County Nursing Home. Because of large amounts of industrial water withdrawals, this wellhead protection area is the largest one on the peninsula. The current pumping rates, dominated by Perdue Inc., show a drawdown area almost as large as the drawdown expected for the maximum, pern-dtted pumping rates. The WPA extends into both the Bay and the Atlantic, and includes Bloxom to the north and Melfa to the south, and Accomac, Parksley, Onley, and Onancock in the central portions. WPA C contains the Boggs septage lagoon. Two public water supply wells for the Town of Parksley have had nitrate nitrogen levels ranging from 5.65 to 8.5 mg/I during testing intervals between 1974 and 1989. An observation well sampled in 1980 measured 10 mg/I for nitrate-nitrogen. Wellhead Protection Area D - Exmore Area Area: 65,000 acres Number of Wells: 9 and 1 proposed Number of VPDES dischargers: 9 Landfills: 1 Lagoons:1 WPA D covers the border of Accomack and Northampton Counties. The southern landfill for Accomack County and a Bundick Lagoon is located within its boundaries. To the east, the boundaries cover most of Paramore Island and Hog Island, and it extends far out into the Chesapeake Bay on the west side. The villages of Keller and johnsontown are the north and south extents of wellhead protection area B, respectively. Also included are Pungoteague, Wachapreague, Exmore, and Nassawadox. Wells are in use for the town of Exmore, Virginia Landing Campground, the Accomack-Northampton Hospital, and American Original Foods. Peaceful Beach Campground plans to install a well in this wellhead protection area. An observation well on Churchneck has measured very high nitrate nitrogen levels, ranging from 13.0 to 24.0 mg/l. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 5-7 Wellhead Protection Area E - Cape Charles Area Area: 52,000 acres Number of Wells: 17 plus 7 proposed Number of VPDES dischargers: 13 Landfills: 1 Lagoons: none This wellhead protection area is the most southern on the peninsula, not quite reaching Fisherman's Island. Similar to WPA D, its boundaries include most of the marshland on the east, and extend out to a large distance into the Bay. Machipongo is the northernmost town, and Eastville' Cheriton, Cape Charles, and Townsend are all included in the protection area. Major wells in the area are presently proposed but pem-titted, and include wells for the DiCanio and Brown & Root communities near Cape Charles. Current water withdrawers; are the towns of Eastville and Cape Charles, America House Motor Inn, Sea Watch International, KMC Foods, and Bayshore Concrete Products. The Northampton County Landfill is also located within this area. A Brown and Root well sampled in 1977 had a nitrate-nitrogen level of 17.0 mg/l, and an observation well near Oyster exhibited nitrate-nitrogen levels ranging from 6.9 to 9.0 mg/l. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 5-8 I I I I I WATER BUDGET/BALANCE 6 1 1 I I I I I I I I I I I I SECTION 6: WATER BALANCE Because aquifer and wellhead protection is so intimately tied to the issues of water quality and quantity, some quantification of the amount of recharge both to the unconfined and confined aquifer systems was needed. The estimate of the available water could then be compared to the amount extracted in terms of current, permitted and future yields. RECHARGE TO THE COLUMBIA AQUIFER An estimate of the amount of water recharging the unconfined Columbia aquifer as made using a standard water budget calculation (Appendix E) following the approach detailed in Dunne and Leopold, 1978. A water budget is calculated by creating a "balance sheet" of hydrologic inputs and outputs to the system. The input to the system is precipitation. Average values for monthly precipitation from the weather station at Painter, Virginia were used, representing six years of record (1985-1990). Outputs from the system include the amount of water evaporated directly or transpired indirectly to the atmosphere, estimated using an approach from Thomthwaite and Mather (1955) (Appendix E). The Thornthwaite and Mather approach is designed for use in temperate and humid environments and is an appropriate choice to estimate potential evapotranspiration (ET) on the Eastern Shore. Where ET is greater than precipitation, a potential water loss develops and accumulates during the dry months (June, July and August). The amount of moisture held in the soil (a function of soil type and plant rooting depth) will be reduced because of this accumulated water loss. Calculations are then made to estimate the actual ET and to determine the amount of water available for runoff and recharge. The water budget approach resulted in an estimate of 17 inches per year of recharge to the unconfined Columbia aquifer on the Eastern Shore, assuming 50 % runoff, 12 inches per year with 60% runoff and 26 inches per year with 40% runoff. The water budget modelling is fairly robust with regard to most of its components. Temperature and precipitation records show only moderate scatter, characteristic of a temperature climate. The fact that relatively little soil moisture deficit develops is typical with the climatic regime of the Eastern Shore. Where the model does show sensitivity is in the estimate of the amount of runoff that takes place. The Soil Conservation Service (SCS) models of runoff calculations are only applicable to small catchments, and empirical estimates for runoff percentages are difficult to obtain at the scale of the entire peninsula. Given the permeable nature of soils on the Eastern Shore, a 50% estimate is reasonable (Dunne and Leopold, 1978). If 40% is estimated to run off, the recharge estimate jumps to approximately 26 inches per year. If 60 percent runoff is estimated, about 12 inches per year recharges the aquifer. The volumetric amount Of recharge is determined by multiplying the recharge rate by the area of the peninsula. Using an area of 400 square miles and 17 inches of recharge per year, the volumetric recharge to the unconfined aquifer is approximately 324 million gallons per day. Most of the withdrawals from the surficial aquifer consist of agricultural extractions, and many are undocumented. However, it can be fairly safely maintained that the withdrawals do not approach even within an order of magnitude of the amount being recharged. The quantity of water within the Columbia aquifer appears to be of little concern. RECHARGE TO THE YORKTOWN-EASTOVER AQUIFER The days and silts separating the unconfined Columbia and the confined Yorktown-Eastover aquifers range in thickness from 20 to 100 feet. The permeability of this confining layer is low, but precisely how low is difficult to determine empirically. To calculate the flux across the confining layer for transient (time-dependent) conditions using Darcy's Law, some value for Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 6-1 hydraulic conductivity (permeability) has to be used. To avoid this problem, and to obtain a conservative estimate of recharge to the Yorktown-Eastover aquifer, HWH used as steady state approach to calculate recharge. Recharge was determined via a cross-sectional model for the confined ground water system. The governing differential equation for one-dimensional flow at steady state was integrated and boundary conditions appropriate to the Eastern Shore used to determine the constants of integration. The result was an equation that could be solved for a recharge rate (see Appendix E). The recharge rate was multiplied by the area of the confining layer receiving recharge to determine the volumetric quantity of water reaching the confined system. The coefficients necessary to solve the derived equation are aquifer transn-dssivity, hydraulic head (water level), and the width of the peninsula. To examine the sensitivity of the analytical model, a range of values were used to determine an estimate for recharge. The average width of the peninsula is about 8 miles in Accomack County and about 6 miles in Northampton County, although sections exist that are considerably narrower. Calculations were made for widths of 4,6, and 8 miles. Transmissivity values found in geologic reports of the Eastern Shore varied considerably, ranging from less than 1000 ft2 per day to over 5000 ft2 per day. The modelling incorporated a range of transn-dssivity from 500 to 5000 ft2 per day. Values from the potentiometric surface map of Bal, 1977 were used for hydraulic head at the ground water divide, varying from 15 to 26 feet above mean sea level. The results show that recharge to the confined Yorktown-Eastover aquifer is very slow. Calculated rates ranged from 0.01 ft/yr under the worst case conditions to 0.85 ft/yr for a somewhat optimistic scenario of narrow peninsula width coupled with high transmissivity and high hydraulic head. The average recharge rates for the 6 and 8 mile wide peninsula scenarios was 0.13 and 0.07 ft/yr, respectively. These average recharge rates take into account the average widths of the two counties at the selected average transmissivity values, but do not account for the large variability (more than a factor of two) in each of these numbers as discussed in Appendix E (Page E-6). These average rates also coincide with the conceptual model of a fairly restrictive confining layer separating the Columbia and the Yorktown- Eastover aquifer. Recharge in the model changes directly in proportion to transmissivity increases and hydraulic head increases, but reacts oppositely to changes in the width of the peninsula. The model is quite sensitive to differences in peninsula width. With a decrease of 2 miles (8 to 6 miles, or 6 to 4 miles) recharge more than doubles. The model is also sensitive to values of transn-dssivity. Over the anticipated range of 500 to 5000 ft2/day, recharge values approximately double with each 1000 ft2/day increase. The model is least sensitive to hydraulic head, primarily because of the restricted range of heads that are used. Each 2 foot increase in head translates to about 0.01 ft/yr increase in recharge. While the rate of recharge is quite low, the volumetric total of water that enters the confined system is fairly large. However, the conceptual model demonstrates that recharge does not occur across the entire area of the confining layer. Rather, it occurs predon-dnantly over the central portions (Figures 2-6 and 2-7). Therefore, multiplying the calculated recharge rate by the entire area of the peninsula on the assumption that all of the confining layer surface pern-dts recharge would incorrectly inflate the volumetric total entering the confined system. A range of areas smaller than the entire Eastern Shore was used to estimate the volumetric recharge to the confined Yorktown-Eastover aquifer (Appendix E). Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 6-2 Using an area of 200 mi2 and a recharge rate of 0.10 ft/yr (averaging 0.13 and 0.07 ft/yr), there is some cause for concern in terms of water quantity in the Yorktown-Eastover aquifer. At a 0.10 ft/yr recharge rate, pumping at the permitted amount of 15.6 MGD would create a deficit situation, in effect, mining the ground water of the confined system. Even when considering a recharge area of 300 md2, the volumetric total at 0.10 ft/yr is within 3 MGD of currently permitted use. If the Yorktown-Eastover aquifer is receiving recharge at a rate of 11 MGD, and the maximum withdrawal volumes could reach 15.6 MGD according to VAWCB issued permits, then significant problems could develop in the future. Continuous drops in hydraulic head and increases in chloride levels have been observed in VAWCB test wells in the vacinity of the largest industrial withdrawal wells. If maximum withdrawals reach 15.6 MGD, then salt water intrusion (lateral and upconing), well interference and water quality degradation of the Yorktown-Eastover aquifer, already observed near major industrial users, will be aggravated. In view of these results, serious consideration should be given to (a) better quantification of the amount and distribution of recharge that enters the confined system, (b) careful examination of additional permits for large volume water users that would increase the amount of pumpage significantly beyond current levels, and (c) reevaluation of existing permits relative to actua I use and need. SALT WATER INTRUSION Serious questions exist relating to the issue of sheer water quantity that can be extracted from the Eastern Shore's confined system. Of equal importance to the amount of water being extracted is the issue of where the water is being taken from. In particular, consideration for the problem of salt water intrusion has to be considered. Salt water intrusion to a fresh water aquifer can occur in several ways. Intrusion can occur from lateral inflow of salt water into the fresh water zone. In this scenario, salt water is viewed as a wedge that pushes in to the fresh water lens as fresh ground water head declines because of a drop in area] recharge or from pumping of wells in the fresh water zone (Figure 6-1). Several analytical models have been developed for the analysis and description of flow in a fresh water zone overlying a static body of salt water including the standard Ghyben-Herzberg equation and an approach by Glover, 1959. With confined aquifers, salt water can also intrude vertically through confining layers in response to reversals of gradient. As pumping proceeds or as area] recharge to the fresh water aquifer declines, the hydraulic head in the fresh water zone becomes less than that in the salt water zone. Flow that originally moved upward from the fresh water zone through the confining layer and discharging to the salt water zone reverses. As a result, salt water leaks through the confining layer into the fresh water zone. This problem particularly afflicts wells located along coastal areas. The wedge-like movement of salt water into fresh water zones and the leakage through confining layers from gradient reversals was the subject of the recent U.S. Geological Survey study on the Eastern Shore, using the SHARP interface model (Richardson, in press). That report remains in the U.S.G.S review process and is not yet published. When the results do become available, they should be closely examined to assess the impact of lateral intrusion and intrusion through confining layers, particularly on high volume wells located near the coasts. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 6-3 Figure 6-1 SALT WATER UPCONING FROM WELL WEST EAST Pumping Well Piezometric Chesapeake Surlace Atlantic Ocean Bay . . . ....... r .... .. .. . .... ....... .... .. ....... .... Sail sell .:Gmun mund Iiii ter Fresh Water Aquifer -Fresh Water Aquitard 7 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 6-4 regardless of pumping rate, and a number of analytical equations have been developed to describe this movement of salt water (McWhorter and Sunada, 1977). If a well pumps at too high a rate, the salt water upcone will reach the well and contaminate the supply source. Therefore, pumping fresh water from an aquifer underlain by a salt water zone must be done using very small drawdowns to prevent upconing from reaching the well. It is possible to obtain an upconing of the salt/fresh interface that is stable for a given pumping rate, the thickness of fresh water zone and particular well construction. In practical terms, the salt/fresh interface is usually stable if the upcone rises less than one third of the distance between the bottom of the well and the original, non-pumping interface elevation. Figure 6-2 Upward Vertical Migration of Salt Water land surface water t M51 ------------- ocean fresh water saline water Several analytical solutions have has been developed to predict the maximum discharge a well can produce given a particular thickness of fresh water, hydraulic conductivity, and distance to a well screen. Three were exan-dned for use on the Eastern Shore (Appendix E). The models are designed to predict the recommended maximum rate a well should pump to avoid the problem of moving the salt water upcone beyond the critical level of stability. Two of the models selected (McWhorter, 1972 and McWhorter and Sunada, 1977) are designed for cases of partial penetration of a well, in circumstances where the screened portion of the well is small in relation to the total depth, a common factor to virtually all wells on the Eastern Shore. The third approach (Bennett, 1968 in Reilly and others, 1987) incorporates a recharge factor into the calculations. The upconing models were applied for conceptual purposes to obtain an idea of the magnitude of the problem of upconing. The aquifer was modelled as a single confined unit, ignoring intermediate confining and sen-d-confining layers to simplify the analysis. Parameters needed for the modelling (e.g.,thickness of the undisturbed fresh water zone, position of well screen, hydraulic conductivity, etc.) were determined for a high volume producing well, Perdue #2, taken from the literature. In particular, the elevation of the pre-pumping salt/fresh interface was designated at the elevation of the the 250 mg/I chloride level, calculated by subtracting the mapped 250 mg/I chloride surface elevation (Fennema and Newton, 1982) from the pre- pumping water level surface elevation (Bal, 1977). Water with more than 250 mg/I tastes salty Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 6-5 and is generally unacceptable for most domestic and industrial uses. While the 250 mg/1 chloride level does represent a limit of potable water, it is not a true salt/fresh water interface. The allowable discharges produced by all the upconing models are directly proportional to the difference in density between the salt (usually sea water) and fresh water, generally estimated at 0.025 mg/l. The density differences between fresh water and water with 250 mg/1 chloride is negligible, resulting in trivially small allowable discharge rates. To make use of these analytical tools even for conceptual purposes, the density difference had to be maintained as that between sea and fresh water. The results (Table 6-1) show the models predict considerably lower levels of pumping discharge rates than either permitted or existing rates in order to maintain a stable upcone. The , predicted rates for this well range from a low of 20 gpm from an extremely conservative model to 80 gpm, using the Bennett and other, 1968 model that incorporates recharge. However, if a true salt water interface existed at the 320 foot level (with a chloride concentration of approximately 30,000 mg/1), this well and most all high volume wells on the Eastern Shore would have been contaminated at either their permitted or actual rates. Table 6-1: Salt Water Upconing Modelling Results Well: Perdue #2 Model Input Parameters IDischarge Data Screen bottom elevation 253 ft msl Permitted discharge (gpm) 503 Salt/fresh interface 320 ft msl Actual discharge (gpm) 278 Thickness of fresh water 340 ft Areal Recharge 0.10 ft/yr Hydraulic conductivity 37.5 ft/day Modelled allowable discharge to prevent upconing Model from McWhorter, 1972 20 9PIn Model from McWhorter and Sunada, 1977 46 8PIn Model from Bennett and others, 1968 80 SpIn The reasons why sea water does not flow from the wells of the Eastern Shore is a combination of several factors. The models assume a sharp interface between the salt and fresh water, a phenomenon that rarely occurs in field conditions, especially if pumping is intermittent. Instead, the salt/fresh interface usually forms a gradational zone from highly saline or brackish water to fresh water. Also, as indicated above, the interface position used in the modelling was not assumed to be a pre-pumping true interface (approximately 30,000 mg/D. The model instead used a post-pumping 250 mg/I chloride level, which is not a true salt water/fresh water interface. The actual position of salt water lies somewhat below the level used in the modelling, below the confining layer that separates the lower Yorktown-Eastover Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia 6-6 modelling was not assumed to be a pre-pumping true interface (approximately 30,000 mg/1). The model instead used a post-pumping 250 mg/I chloride level, which is not a true salt water/fresh water interface. The actual position of salt water lies somewhat below the level used in the modelling, below the confining layer that separates the lower Yorktown-Eastover aquifer from the underlying unit, the St. Mary's Formation. None of the models used incorporates a low permeability unit into the calculations, and salt water intrusion from upconing would be slowed by the presence of a lower boundary of silts and clays. The results of this modelling should serve not as any sort of regulatory tool but as a warning that large discharges will promote salt water contamination from upconing unless pumping rates and intensities are regulated. Also, the primary issue at hand is not whether sea water with a chloride concentration of 30,000 mg/I is actively intruding into the fresh water aquifer. The more important question is whether water that possesses chloride concentrations of 250 mg/I and is essentially useless for direct consumption, either as drinking water or as industrial use water, will be drawn into the wells. In all likelihood, that is probably happening now in a number of wells on the Eastern Shore despite the fact that samples from most wells show lower overall concentrations. Most wells completed in the Yorktown-Eastover aquifer have screens in all three layers and draw water from all three. The lower Yorktown-Eastover is often the least transmissive of the three and contributes the least water. The overall result is that a mixing of water occurs, and samples taken from a given well represent the bulk chemical signature of all three layers. Water in the upper two layers is not likely to have been affected by high chlorides yet, and dilution masks the elevated concentrations of chloride from the lower section. Salt water upconing will occur with pumping, and careful management of the resource is required to avoid irreparable damage to the fresh water aquifers. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 6-7 I I I I BUILDOUT/DEVELOPABLE LOT ANALYSIS I 7 1 I I I I I I I I I I I I I SEMON 7: BUILDOUT DEVELOPABLE LOT/LAND USE ANALYSIS Of the total land area on the Eastern Shore (about 537,000 acres), approximately 38 percent or 206,000 acres are wetlands and coastal islands, not suitable for residential, agricultural or industrial use. Approximately 53% of the land area on the Eastern Shore is under agricultural use or forestry. The remaining 9% of the land is under residential use (3.2%), commercial/industrial use (0.6%), in the public domain (2.4%), or other uses (2.3%) (Table 4-1, p. 4-3.). With the exception of sewage treatment plants servicing the towns of Cape Charles and Onancock, existing development on the Eastern Shore relies on individual subsurface disposal systems for sewage treatment. No large-scale sewering is anticipated in the future. Residential development is scattered, with a low density pattern of development overall. Commercial and industrial development is concentrated along the center strip of both counties, following Route 13. Drinking water is supplied by a combination of public water supply and private wells. Zoning requirements (dimensional and use) vary widely, both within the counties, and within the towns. Land use in Virginia is regulated at the county level, with the exception of the areas within incorporated towns. Land use in these areas is regulated by the towns themselves. The authority for local governments to zone land in Virginia is granted by the Virginia General Assembly and can be found as Article 8 of the Code of Virginia. The Virginia Zoning Code cites ten general purposes for zoning including "to protect surface water and groundwater" (VA Code Ann. sec. 15.1-489). The Zoning Code also authorizes conditional zoning, site plan ordinances, and the provision for variances. In addition, local governments are required to develop a comprehensive plan for "the physical development of the territory within its jurisdiction" ( VA Code Ann., sec. 15.1-446.1). The comprehensive plan becomes the general plan for development and the basis for the formulation of zoning ordinances in the local jurisdiction. Specifically, the code requires local governments to include in their plans "the designation of areas for the implementation of reasonable groundwater protection mea5ures" (VA Code Ann,. sec. 15.1-446.1). Local control over development can also be found in the State's law controlling land subdivision (VA Code Ann. sec. 15.1-465). This authority can be particularly important in an area such as the Eastern Shore where very little land is currently subdivided into smaller residential lots. A land use control measure that recently became available for use in Virginia is found in the Chesapeake Bay Preservation Act (VA Code Ann. sec. 10.1 -2100). This new law passed in 1988 requires that counties, cities, and towns of Tidewater Virginia incorporate general water quality protection measures into their comprehensive plans, zoning ordinances, and subdivision ordinances. This authority provides very general and broad powers to local governments in Virginia to control land uses that may impact on water quality. Methods The primary purpose of buildout, or developable lot, analysis was to evaluate the impacts of existing and potential land uses on ground water quality. The analysis therefore focused on the Zone 2 spine recharge area, as delineated in this study. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 7-1 The buildout analysis followed a three step process. First, Zones 2 and 3, as delineated in this study, were transferred onto US Geological Survey 1:25,000 scale topographic quadrangles for Northampton County and Accornack County land use district maps, also at 1:25,000 scale. Secondly, existing land uses within the spine were documented. The potential for further development was determined from future land use maps prepared for both counties, and the information was transferred onto the set of 1:25,000 scale maps. An example of future land use within the spine is shown on Figure 7-1. The Soil Conservation Service (SCS) identified the Nimmo-Arapahoe soil association as the only upland soil type in the two counties that is considered undevelopable (R. Lewis, personal communication, 1991). Areas with these soils were identified on the land use maps, and analyses were conducted with and without inclusion of these areas. Small regions of hydric soils were not factored into analyses. Finally, areal extent was measured for each future land use class, subdivided by county, ground water protection zone, and soil class. Fifteen percent (15%) of developable land was taken out for roads within each land use category. All data used in the analysis was entered into a computerized spreadsheet program (Microsoft Excel), to aid sorting and analysis. The spreadsheet was programmed to perform the necessary calculations for the various buildout scenarios. The total future number of units was calculated by taking the total land area within each land use category in each protection zone, subtracting out 15% for roads and poorly drained soils. The remainder was divided by the permitted number of lots per acre under current zoning (Northampton) or recommended zoning (Accomack Comprehensive Plan, 1989). Table 7-1 lists parameters used. Table 7-1: Minimum Lot Sizes Used in Buildout Analysis Accomack Cotmjy Northampton Counjy RR: Rural Residential 1 unit/acre Residential 20,000 ft2 R-1: Residential 3 units/acre Agriculture 43,560 ft2 R-2: Residential 2 units/acre Agdculture: 1 unit/5 acres Source: Accomack County Comp. Plan, 1989 Northampton County Zoning Ordinance, 1990 The analysis results have important implications for the assessment of nitrogen contamination of ground water and for the development of appropriate regulatory approaches in protecting ground water quality on the Eastern Shore. Buildout Assumptions For incorporated towns in Accomack County certain assumptions were made in order to complete the buildout analysis. Each town has its own zoning which is not included in the Future Land Use Plan for the County. The following assumptions were made: 1) The percentage of the town which lies within the spine was determined by taking the ratio of acres of town within the spine to total acres of incorporated town. 2) The breakdown of land use types was assumed to be equivalent to that of the entire county, leaving out agriculture, parks, and marshland. In Accomack County, it was estimated that 75% is residential, 1.8% is trade, 17.5% is industrial, and 5.3% of is institutional. These percentages were Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 7-2 Fig= 7-1: Example of Future Land Use Within Spine Recharge Area TOW Of Wfa ............ -------- ....... sov ............. ...... Arm .... .......... P 13::' ... ..... ... .......... own of Keller R RR: Rural Residential (1 unit/acre) - 1: Residential (3 units/acre) Industry Institutional Agricufture (I unit5 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 7-3 multiplied by the acres of each town which fall on the spine. Ain estimate of acreage by land use within the town was thus achieved. 3) Using the estimated potential residential acreage in each town from (2), the number of potential dwelling units was calculated. An average of 2 units per acre was used. For Northampton County, there are two types of residential land delineated on the future land use map, Rural Residential (and village area) and Urban Development Area. In the Comprehensive Plan, each urban development area is broken down into residential, commercial, industrial, roads/railroads and public land areas. The maps showing the locations of these types are inadequate for transferral to the USGS quadrangle maps. Therefore, land use within the urban development areas was estimated. Proportions of each land use type within the spine were assumed to be equivalent to that of the area as a whole; and residential land was separated from other types within each urban development area. Calculations within incorporated towns and Urban Development Areas are included in Tables 7-3 and 7- 4. BUILDOUT ANALYSIS RESULTS Buildout results are summarized in Table 7-2; complete results are shown in Table 7-5. Table 7-2: Buildout Summary Existing Units Total Acres Res./Ag. Acres Potential Units Accomack County Counjy-wide within [email protected] within spine within spine developable soils 17,140 16,561 15,893 all soils 15,840 22,147 19,901 16,470 Northampton County all soils 6,183 16,921 15,535 21,207 In both counties, the potential number of single-family dwelling units within the spine recharge area, according to current plans, is greater than the number of units that currently exist within the entire two counties. While the number of potential housing units may be striking, development is currently slow on the Eastern Shore of Virginia. Indeed, the population has actually decreased in the past decade. Consequently, there is opportunity to enact management tools to control future development and thereby protect ground water quality and quantity. BUMDOUT ANALYSIS SLUAMARY The buildout analysis used a computerized spreadsheet approach to determine the maximum number of future residential units in both counties. The buildout focused on land areas within the delineated spine recharge zone (Zone 2) to the Yorktown-Eastover aquifer, since this area would most likely affect public water supply quality. Using minimum lot size requirements according to each county's comprehensive plan, the maximum number of units or houses that could be possibly built was calculated. In Accomack County this resulted in 16,470 potential units in the spine recharge area. For Northampton County, the maximum potential number of units was calculated to be 21,207 (Table 7-2). As discussed previously, this results in more potential units than that which currently exist within each county. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 74 Table 7-3c Calculations for Buildout Within Incorporated Towns, Accomacic County CALCULATIONS OF CURRENT DWELLING UNITS WTI`HIN SPINE Incorporated Acres within Total acres % of town 1990cmust Estimated dwelling Town spine oftown withinspine dwellingunits unitsinspine Accornac 173 262 66 205 136 83 486 17 276 47 154 177 87 191 166 ,Keller 1 211 1 214 98 1 107 1 105 1 IPainter 1 184 1 415 1 1 113 1 5D lbelle Haven 1 408 1 3M I so 1 245 1 122 CALCULATIONS OF LAND USE WITHIN TOWNS Acreage in Estimated acreage Estimated Acres Land Use county within towns M) Accomac Onley Melfa Keller Painter Belie Haven Residential 4.3 75 131 63 116 159 138 308 Trade 0.1 2 3 2 3 4 3 7 Industrial 1.0 is 30 is 27 37 32 71- lInstitutional 0.3 5 9 4 8 11 10 1 22 117otal 5.7 100 173 84 1 154 211 1 184 1 408 MAXEAUM POTENTIAL DWFELLING UNITS WITHIN SPINE Estimated Residential aczes Average Potential Existing Nlaximum Town residential acres subtracting 15% units/acre dwellings in dwellings Additional for roadwa spine in spine Units Possible Accornac 131 ill 2 Z22 136 86 Onley 63 54 2 107 47 60 Melfa 116 99 2 197 166 31 ,Keller 1 159 131 2 270 105 1 165 1 11'ainter 138 118 2 2W so 185 Bell* Haven 305 261 2 523 122 401 1 Table 7-* Calculations for Buildout WIthin Urban Development Areas, Northampton CAUMY CALCULATIONS OF CURRENT DWELLING UNITS WITHIN SPINE Urban Development Acres within ToW acms % of area CurmatPopulation Estimated #personst Estnumberof Area spine of area within spine (Comp. Plan) Pop, in spine dwelling dwelling units (1990 Ono") in spine Exmore/WWis Wharf 1,164 4,225 28 Z684 740 2.1 350 Nassawadox 12M i'm 66 1,775 1,174 2.1 556 Eastville 1,423 2277 63 800 500 2.1 237 lCheriton/Cape Charles 1 1,448 1 5,428 1 27 1 4,274 1 1,140 1 2.1 1 540 1 LAND USE WITHIN URBAN DEVELOPMENT AREAS ACCORDING TO COMPREHENSIVE PLAN Land Use Exmore/ Nassawadox Eastville Cheriton/ Willis Wharf Cape Charles Residential 65 88 77 66 Commercial 5 7 3 4 Industrial 6 2 2 7 Roads/Railroads 17 1 is 19 jPublic -1 7 1 2 1 2 1 5 1 hWaMUM POTENTIAL DWELLING UNITS WITHIN SPINE Urban Development Area Estimated Minimum lot Potential Estimated Nlaximum residential acres size dwellings in existing Additional within spine (acres) spine dwellints in spine Units Possible Exxnore/Willis Wharf 7S9 0.46 1,650 350 1,300 Nassawadox 1,076 5.46 2,340 556 1,784 Eastville 1,096 --5-.46 -2,382 237 Zl" iCheriton/Cape Charles 1 948 10-46 1 Z061 1 540 1 1IS22 1 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 7-5 This buildout has important implications for wastewater disposal impacts and future water supply needs. Obviously, not every possible unit will be developed in the near future, however the buildout assessment expresses the "blue print" that has been established for growth by both counties. If this development were to occur, then significant water demands and wastewater disposal needs would have to be addressed. For the combined total number of units of 37,677, a water demand of 5.65 MGD (37,677 units x 150 gallons per day) would be needed. As of 1990 only 1.2 MGD is supplied by public water sources. Public water withdrawals would have to increase by over 4.5 times. Regarding wastewater disposal, if all of these units were allowed to be built, then a total of 6.22 MGD of wastewater (37,677 units x 165 gallons per day) would have to be either treated and disposed to the ocean or Bay, or be discharged to the ground water through septic systems. Further analysis of wastewater impacts under buildout conditions is discussed in Section 8. The numbers generated in the buildout were used in the nitrogen loading model to detern-dne maximum nitrogen loading under the planned densities and land use types for both counties. The buildout numbers for maximum number of units, agricultural areas, etc. are used to predict nitrogen loading under the current land use plans, and to allow for scenario testing of different land use patterns. This buildout analysis can be used as a predictive tool to help assess the impacts of future development on the many community services that would be needed to support this level of development and to help plan for changes in development densities and patterns of future development. In reality, the near future will only see a fraction of this buildout potential due to market conditions and other factors. Buildout analyses such as this one can be used to identify potential land use conflicts and to begin to plan for changes to address these conflicts. Ground Water Supply Protection and Managernent Plan for the Eastern Shore of Virginia 7-6 Table 7-5: Developable Lot Analysis, Accomack and Northampton Counties ACCOMACK COUNTY Measurements in acres jPermitted WPA @[email protected] Potential Potential Developable Undevel. Total Units/ Units Units Land Use Type Acres Acres Acres Acre Dev. soils All soils RR. Rural Residential 1 12 12 1 0 10 1 R-1: Residential R-2. Residential Trade 60 60 Industry Institutional Parks & Recreation Agriculture 161 3,183 3,344 15 acres 27 Total 161 32% 3,417 27 579 jPermitted WPA @B Potential Potential Developable Undevel. Total Units/ Units Units Land Use Type Acres Acres Acres Acre Dev. soils All Soils RR. Rural Residential 733 1 733 1 1623 623 1 R-1: Residential 3 R-2- Residential 29 29 2 50 50 Trade 626 626 Industry 197 187 Institutional 29 29 Parks & Recreation Agriculture 3,164 145 3309 11 /5 acres 1 538 363 Total 4,769 145 4,915 11211 1,236 Permitted WPA-C--7 I Permitted WPA= Developable units/ Potential Developable units/ Potential Land Use Type Acres acre Units Acres acre Units RR;- Rural Residential 1,220 1 1,037 401 1 341 R-1: Residential 2,985 3 7,612 899 3 2,292 R-2- Residential 205 2 34F- 312 2 sm Trade 585 Industry 197 71 Institutional 181 10 Parks&Recreation 0 Agriculture 3,726 1 /5 acres 1 633 11811 1 /5 acres 308 Incorporated Town 410 8M residential 3-10 2 526- 605 2 1,028 triade 7 14 industrial 72 '40 institutional r -22 43 Totals by area 9,509 10,157 4,306 4,498 NORTHAMPTON COUNTY jPermitted WPAD [-Permitted WPA E I Developable units/ Potential Developable units/ Potential I.and Use Type Acres acre Units Acres acre Units Rural Resid. & Village Area 628 2.178 1,163 2,218 2-178 4,105 Urban Development Area 2,394 2,871 residential 1,836 2.178 3,998 2,044 2.178 4,452 OCHrunercial 151 ill industry 96 128 roads/radroads 2D6 490 public 170 98 Agricultural or Forestral Area 3,102 1 1 1 2,637:@ 5,707 Total by Area 6,125 7,798 10,7% 13AO9 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 7-7 I I I I I NITROGEN LOADING 1 8 I I I I I I I I I I I I I SECTION 8: NITROGEN LOADING INTRODUCTION Nitrogen is present in surface and ground water environments in four primary forms. The forms are organic nitrogen, ammonium-nitrogen, nitrite-nitrogen and nitrate-nitrogen. Organic nitrogen consists of a variety of soluble, colloidal and particulate forms. Ammonium-nitrogen (NH4+) is characteristic of poorly oxygenated (anaerobic) conditions and is readily adsorbed by soil particles in the unsaturated, oxygenated zone above the water table where it is rapidly converted to nitrate-nitrogen. However, ammonium-nitrogen may travel long distances in areas where the saturated zone is anaerobic. Ammonium-nitrogen is the primary form of nitrogen in septic system effluent and in wetland soils. Nitrite-nitrogen (NO2) is an unstable form which is rapidly transformed into nitrate-nitrogen, and so is usually present in very small quantities. Nitrate-nitrogen (NO3) is characteristic of oxygenated (aerobic) conditions and is highly mobile in ground water. In this form, nitrogen may travel long distances with little attenuation. (Freeze and Cherry, 1979; Canter and Knox, 1986) Nitrogen transformations are complex, bio-physio-chen-dcal processes. Figure 8-1 illustrates some of the common nitrogen transformations, described below. The process by which organic nitrogen is transformed to ammonium-nitrogen is called mineralization or ammonification, and occurs under both aerobic and anaerobic conditions. The process whereby ammonium-nitrogen is transformed to nitrate- nitrogen is called nitrification and occurs under aerobic conditions. Denitriftcation is the process by which r-dtrate-nitrogen is converted to gaseous forms such as N2 and released to the atmosphere. Denitrification occurs under anaerobic conditions, particularly within wetland soils. The opposite transformation, whereby atmospheric nitrogen is converted to ammonium nitrogen is called nitrogen fixation, and is performed by bacteria and blue-green algae (cyanobacteria). (Freeze and Cherry, 1979; Canter and Knox, 1986) NITROGEN AS A CONTANIINANT Although all forms of nitrogen are critical components of natural systems, nitrogen can cause water quality degradation if present in excessive quantities. In drinking water supplies, elevated nitrate- nitrogen levels can cause an illness known as infant cyanosis, methemoglobinemia, or "blue-baby syndrome" in infants, caused by the alteration of hemoglobin and subsequent problems with oxygen transport. In addition, high nitrate-nitrogen levels have been linked to the formation of carcinogenic nitrosan-dnes (Porter, 1978). To reduce potential health risks, the U.S. EPA has established a drinking water standard of 10 milligrams per liter (mg/1) for nitrate-nitrogen. A statistical analysis of ground water samples collected on Long Island, New York, demonstrated that when median nitrate-nitrogen concentrations were 6 mg/l, 10 percent of the samples exceeded the 10 mg/l drinking water standard (Porter, 1978). To account for this variability, the Cape Cod Planning and Economic Development Commission (CCPEDC) and several towns across the state of Massachusetts have adopted a more conservative concentration of 5 mg/l, as a planning guideline. ne Virginia State Water Control Board adopted a ground water standard of 5 mg/I for nitrate-nitrogen in the early 1970's. Since then, the anti- degradation policy supersedes these standards. In the case of Virginia, the numeric limits are meant as guidance and are for permitted discharge. The ground water standards are different and separate from drinking water standards, and are not levels that have to be reached should a clean-up be necessary. (T. Wagner, SWCB, personal communication, 1991). Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-1 Figure 8-1: Nitrogen Transfomiations Precokation f WH-!l INOil IN031 Mineral Plant Residue, Sewage Fwffim Compost Organic - N NH -3 Organic - N NH3 N03 Proteins N L NH 3 N Z Wrogen Fixatim Decomposition Nitrification Nitrifiication [email protected] Proteins Decomposition F 4 Denkrification NH" Denitri NHq Denitrification q A;;[email protected] F Adsorption Nitrification N03 N03 NOj Leaching - - - - - - - - - - - - - - - - - - - - -- Ground Water N0j Ground Water NOj - - - - - - - - --- (Denitrification in Reducing Zones) N zO] FN [email protected] F fication 1P @NOj Adapted from Freeze and Cherry, 1979. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-2 SOURCES OF NrrROGEN Nitrogen originates from a variety of natural and anthropogenic sources, including sewage, fertilizers (residential and agricultural), road runoff, precipitation, landfills, and wildlife. A discussion of published loading rates for these various sources is provided below. Sewage Sewage-derived nitrogen may be produced by a variety of sources, including sewage treatment plants, septage lagoons, on-site sewage disposal systems, exfiltration from leaking sewer mains and combined sewer overflows (CSO's). On the Eastern Shore, on-site sewage disposal systems are the primary source of nitrogen to the ground water. The quantity of nitrogen produced by a given on-site sewage disposal system is a function of the volume and concentration of the effluent discharged, which, in turn, is dependent on the per capita water usage and the occupancy rate. Daily rates of water use may range from 36 to 150 gallons per person per day (EPA, 1980; Nelson et al., 1988) with average rates on the order of 50 to 75 gallons per day (gpd). In estimating sewage flow rates, however, it is important to differentiate between the amount of water actually used and the amount ultimately discharged to ground water as sewage flow. Typically, 20% of the water used may be lost through evaporation or transpiration during irrigation and other outside uses (Nelson et al., 1988). For the purpose of this study, a ground water discharge rate of 55 gpd per capita was used for sewage flow. Quantification of household populations is very difficult, particularly in seasonal communities such as the Eastern Shore, where summer populations may be significantly higher than winter populations. For the purpose of this investigation, an average annual occupancy rate of three people per household was used, based on average occupancy rates as determined for Northampton County. However, a sensitivity analysis was conducted to evaluate household populations ranging from two to four people. A review of the literature indicates that nitrogen concentrations in raw sewage may range from 20 to 100 mg/l. Once sewage enters a properly functioning septic system, however, some removal of this nitrogen occurs both within the septic tank and in the soils below the leaching area. Studies have indicated that between 30 to 60% of the nitrogen may be removed in this way (Porter, 1978; Andreoli et al., 1979). Thus, in estimating loading rates from on-site sewage disposal systems, it is important to use nitrogen concentrations in effluent discharging from the leaching area. Data on total nitrogen concentrations in effluent sampled either from the leaching area or from ground water immediately below the leaching area are summarized in Table 8-1. Table 8-1: Total Nitrogen Concentrations in Septic System Effluent Souroe Concentration Bourna et al., 1972 30 mg/l Walker et al., 1973 40 mg/l Dudley and Stevenson, 1973 14 mg/l Magdoff, 1974 31 mg/l Magdoff, 1974 41 mg/l Reneau,1977 23 nig/l Brown and Assoc, 1980 (summary) 37 mg/l Ellis, 1982 34 mg/l Canter and Knox, 1986 (summary) 40 mg/l Nelson et al., 1988 (summgj)@) 34 mg/l Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-3 A critical review of these reports, particularly the more recent ones, suggests that an average effluent concentration of 40 mg/I is a conservative yet defensible value to use in evaluating water quality impacts of on-site sewage disposal. This value was used in our analyses. Using a flow rate of 55 gallons /capita /day and an average effluent concentration of 40 mg total nitrogen/I, the average loading rate per capita is 6.72 lbs N/year. Fertilizers Agricultural fertilizers are usually the primary nitrogen source to ground water in heavily farmed areas. Accomack and Northampton Counties are predominantly agricultural, with land in farms accounting for approximately 53% of the total land area. In Accomack County, poultry production is the main industry. The predon-dnant crop grown in the two counties is soybeans, a plant which is a nitrogen- fixer and so does not require nitrogen fertilization. The remaining acreage of crop land requires a significant amount of fertilizer (see Table 3-5). For Accomack County this averages 89 lbs/acre and in Northampton County the average agricultural nitrogen application is 79 lbs/acre. Fertilizer and manure applications and poultry production may contribute large quantities of nitrogen to the underlying aquifer depending upon the agricultural management practices in use. The application, production, and storage of fertilizers and animal wastes result in the most important nitrogen contributions. From the Cooperative Extension Agents in both counties, information was gathered regarding crop type acreage and fertilizer application rates. This was used to calculate an average fertilizer application rate of 84 lbs N/acre/year, for all agricultural areas in both counties. An average leaching rate of 25% was assumed for farm fertilizers. Many researchers have documented nitrogen leaching rates that range from 1%47%( Ritter, and Manger,1985; Bouk, 1984; Bacon, 1989; Bower, 1989; Owens, 1987; and Hubbard, 1986). Nitrogen leaching rates to ground water can be affected by many factors including: crop type, application rates, irrigation, soil types, application timing, fertilizer formulations, and climate. As such, the literature shows a wide range of nitrogen loading values. The value of 25% was chosen since it represents a value most often selected in modelling studies of nitrogen movement, and also because it represents a mid range of the values from the literature. Animal Wastes Given the high levels of organic and ammonium-nitrogen in manure, animal waste may function as both point and non-point sources of nitrogen contamination. Chicken manure, in particular, has a high nitrogen availability rate, making it easily leachable into ground water. If wastes are produced or stored on open ground at poultry houses, rainwater can transport nitrogen by percolation through the wastes and into the soil and ground water. All poultry waste is assumed to be used as agricultural fertilizer for the purpose of this study. Prior to application as fertilizer, most manure remains in the poultry houses until it is cleaned out once or twice per year (J. Belote, personal communication, 1991). Storage of poultry wastes is usually thought to be a source of nutrients and pathogens that contaminate ground water. For this reason, on the Eastern Shore in Maryland, efforts are being made to construct storage sheds for poultry manure, rather than continue the current practice of letting manure pile up uncovered outside. Natural mortality accounts for many tons of dead poultry birds. As explained in Section 3, the practice on the Eastern Shore of Virginia is to either bury or compost the chickens. The majority of chickens which die before being sent to the processing plant die within the first two weeks of life, and it is estimated that given the 1990 population, a total of 1.8 n-dIlion pounds of dead birds had to be Ground Water Supply Protection and Manage7nent Plan for the Eastern Shore of Virginia 8-4 disposed. At 3.3% nitrogen (Keeton, 1980), dead chickens contributed 60,638 pounds of nitrogen to Accomack County in 1990. Lawn Fertilizers Fertilizers applied to residential lawns and golf courses contribute nitrogen to ground and surface waters. The pathway may be either direct, via surface runoff, or indirect, via gradual leaching to ground water. The amount of fertilizer that ultimately leaches into ground water is a function of the type of ground cover, soil characteristics, climate, type of fertilizer used, application rate, and the degree of irrigation /rainfall. A literature review of experiments conducted primarily on turf plots suggests that leaching rates may vary from less than 1% to 80%, depending on site specific conditions (see Table 8-2). Leaching rates rarely exceeded 30%, however, unless extremely high fertilization and irrigation rates were used (e.g. Nelson et al., 1980). Table 8-2: Leaching Rates for Fertilizers Applied to Turf Areas Reference % Leached Brown, 1977 2-27% Brown, 1982 1-18% Chichester, 1977 1-8% Dowdell and Webster, 1980 2-5% Hesketh, 1986 0-31% Mancino, 1980 04% Morton, 1988 2-14% Nelson, 1980 5-81% Petrovic, 1988 0-17% Starr and DeRoo, 1981 4% Based on a review of this data, with particular emphasis on regional similarities, a leaching rate of 30% was selected as a conservative (worst case) average value for nitrogen applied as fertilizer to residential lawns within the study area. The typical lawn size for a given lot will vary widely depending on overall lot size, residential character, and individual preferences. Few quantitative studies have been conducted of average lawn sizes. The Long Island, New York and the Barnstable County, Massachusetts 208 studies both used an average lawn area of 5,000 square feet. More recently, a survey conducted as part of the Yarmouth Water Resources Protection Plan documented an average lawn size of 4,350 square feet on half acre lots (Nelson et al., 1988). There have been no known studies on the Eastern Shore of Virginia regarding lawn sizes and application rates of fertilizers. For this study, an average lawn size of 5,000 square feet was used. Fertilizer application rates are similarly difficult to quantify. The Cape Cod and Long Island 208 studies used an average annual application rate of three pounds per 1,000 square feet. The Yarmouth survey documented a similar annual application rate for homeowners (2.8 lbs/1,000 sq. ft.) and a higher annual application rate for professional lawn maintenance companies (4.7 lbs/1,000 sq. ft.). For this study, an average annual application rate of 3 lbs/1,000 sq. ft., equivalent to 39 lbs N/acre, and a leaching rate of 30% was used. Although lawn fertilization is not a widespread practice on the Eastern Shore of Virginia, these studies are the only means of taking into account any turf maintenance. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-5 Landfills Unlined landfills contribute large quantities of nitrogen to ground water through the decomposition of buried organic matter. Nitrogen loading from landfills was based on nitrogen concentrations in typical leachate, 218 mg/I (Patrick and Quarles, 1983). The area of the landfills was obtained from the Accomack-Northampton Planning District Comn-dssion, and an annual recharge rate of 24 inches per year was used (no vegetation/ transpiration). This yielded a loading rate of 1184 lbs N/acre/year for landfills. Septage Lagoons Three septage lagoons are located on the Eastern Shore. These lagoons primarily receive the contents of septic tanks, pumped out according to proper maintenance procedures. The nitrogen loading to ground water from septage lagoons is a product of the raw sewage load minus the amount attenuated in the septic tank, gaseous losses from the lagoon, and attenuation in the soil during percolation from the lagoon. The nitrogen concentration in raw sewage can vary from 20 to 100 mg/I (Metcalf & Eddy, 1979; Laak, 1980; Douglas, 1986), but the total load depends on the associated sewage flow. Nitrogen loads in untreated waste water have been reported from 8 to 13 lb/capita/year (Porter, 1978; Brandes, 1978; Laak, 1980; Camp and Meserve, 1974). Porter (1978) summarized a number of studies which found an average septic tank influent concentration of 65 mg/l, an average septic tank effluent concentration of 45 mg/l and an average removal of 31%. Additional reduction occurs from gaseous losses from the lagoon and during percolation of septage into the soil. The estimated nitrogen concentration of septage reaching ground water can conservatively be set at 45 mg/l. Pavement and Roof Runoff Sources of nitrogen in pavement runoff include precipitation, soil erosion, leaf litter, street dirt, garbage, and animal waste. Nitrogen concentrations in road runoff can vary by an order of magnitude, depending on spacing between storms, the intensity and duration of a storm, and the tin-dng of sample collection. The highest nutrient concentrations are generally found in the "first flush". A summary of typical road runoff values published in the literature is provided below: Table 8-3: Total Nitrogen Concentrations in Road Runoff Reference Total Nitrogen Concentration Koppelman, 1982 1.49 mg/l Howie and Waller, 1986 1.13-2.15 mg/I Lager et al., 1968 3-10 mg/I Loehr, 1973 3 mg/I Schn-ddt and Spencer, 1986 2.04 mg/I Valiela and Costa, 1988 0.38 mg/l (27 um)* *Dissolved Inorganic Nitrogen only For the purposes of this analysis, a nitrogen concentration of 2.0 mg/I in road runoff was used. For roof- runoff, a nitrogen concentration of 0.75 mg/I was selected (Nelson et al., 1988). Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-6 ESTIMATION OF PAVED AREA/ROOF AREA HWH estimated the total paved road area to be 15% of all land area (Nelson et al., 1988), multiplied by 55% since a typical 40 foot right of way includes a 22 foot width of actual pavement. Driveway surface area was estimated to be 500 square feet and roof area to be 1500 square feet per residential unit (Nelson et al., 1988). Businesses/Industrial/InstitutionaI The nitrogen loading from business, industrial, and institutional facilities was calculated to average the design sewage flow per acre for all current land uses in these areas. From the community, non- community, and non-transient non-community water supply list, population information was obtained for the number of persons served in motels, restaurants, campgrounds, trailer parks, hospitals, and nursing homes, as well as the number of employees working in offices and the number of students attending the schools. These data were then totaled per category and multiplied by the design flow per person, employee, or student, as estimated by the Virginia Water Control Board. From this, the total sewage flow for business, industrial, and institutional areas was obtained for each of the two counties. This number was divided by the number of acres currently under these land uses to obtain an average sewage flow of 423 gal/acre/day. The assumption was made that the sewage from these uses has a similar nitrogen concentration (40 mg/1) to residential sewage. Precipitation Nitrogen concentrations in precipitation vary regionally. As precipitation falls on vegetated areas much of the dissolved nitrogen is taken up by vegetative cover and within the root zone, and thus does not leach into the underlying aquifer. Based upon scientific literature, natural background levels on nitrate-nitrogen in ground water are typically 0.05 mg/l or less. This value was used in our analysis as a representation of natural background conditions. NITROGEN LOADING ANALYSIS The nitrogen loading rates used in our analyses were selected on the basis of the literature review outlined above, and also to correspond with a recently calibrated nitrogen loading model developed for the Town of Yarmouth, Massachusetts (Nelson et al., 1988). The loading rates for sewage and fertilizers originally used in this model have been slightly adjusted to reflect recent findings, which suggest that loading from on-site sewage disposal systems may be higher and loading from lawn fertilizers may be lower than previously thought. The loading rates used in our analysis are summarized in Table 84 below. Once nitrogen has entered the ground water system, ultimate nitrate-nitrogen concentrations can be calculated using a simple mass balance equation, in which nitrogen levels are a function of the annual rate of nitrogen loading and the annual rate of dilution through recharge. Sources of recharge to ground water include precipitation, surface runoff from impervious areas and artificial recharge from on-site sewage disposal. Recharge rates used in the nitrogen loading analysis are summarized in Table 84. The nitrogen loading under existing conditions is presented in Tables 8-5 and 8-6. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-7 Table 84: Nitrogen Loading Values Source Concentration Laading Rate Flow/Recharge Sewage 40 mg N/liter (6.72 lbs N/Person-yr) 55 gallons/ person-day (165 gal/dwelling) Business /Industrial/ 40mg/I 423 gal/lot Institutional Fertilizer (Lawns) (0.9 lbs N/1000 sq ft-yr) 17inches/year Fertilizer (Agriculture) 84 lbs, N/acre-yr, avg. 17inches/year Pavement Runoff 2.0 mg N/liter (0.42 lbs N/1000 sq ft-yr) 34 inches/year Roof Runoff 0.75 mg N/liter (0-15 lbs N/1000 sq ft-yr) 34 inches/year Landfills 1184 lbs N/acre-yr 24 inches/year Septage Lagoons 45 mg/l Precipitation 0.05 mg/I 17 inches/year Source: Adapted from Nelson et al., 1988 NITROGEN MODELLING RESULTS Tables 8-5 and 8-6 present the results of the nitrogen loading model used by HWH to predict nitrogen concentrations in the ground water as a result of existing land use activities. The tables show that for Accomack, the total nitrogen from all sources is expected to result in a ground water concentration of 2.0 mg/l N. The results for Northampton show a similar average concentration of 1.9 mg/I N. These results represent an average nitrogen concentration across the entire county and do not reflect nitrogen concentrations at any specific location in the study area. In Accomack County the majority of the loading of nitrogen is from agriculture (1,055,095 lbs per year). Septic system loading is the second highest source of nitrogen reaching the ground water. These findings reveal that on the average, across the entire county the nitrogen concentrations in the shallow ground water are acceptable. What the analysis does not reveal is that in order for the average conditions to reach 2 mg/I of nitrogen that there are many areas that will have significantly higher ground water nitrogen values. Northampton County results show that the same categories of nitrogen inputs are contributors to the overall concentration of nitrogen in the ground water, however there are no septage lagoon and animal burial inputs. Even though the total nitrogen load in Northampton County is lower than in Accomack County (406,258 vs. 1,055,095 lbs/year) the resulting final recharge nitrogen loading concentration is approximately because the total recharge to the ground water is lower in Northampton County. The results show that based on existing land use conditions, nitrogen concentrations in the shallow ground water are on the average acceptable and within state and local drinking water standards. These results are compared with existing water quality testing in the next section. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-8 Table 6-3c Mirage& LeedLng CAlcukidow, Accomack Exind, INFUTFACTORS Number of Rmdefdial VDAft L%340 Sawrapfloorperhouse(PI/day) 165 CommercLaWndw-rial lead (acme) 1 3,701 CAmalawl. arvoup flow Per acre 1 423 (gal/day) [email protected](negil) 1 40 Learn am Per I faclame few 1 5.000 Favemmuperhaventaquaraled) I sw Rand am (aclume fmo 1x6K000 Read arm per hama, ( I few IAN Agricultural am (acres) 47,4"__ [thaaa acres &4* are forwizedl Lawfins taalw SaPtaffe I%- (Pumue" Sep"I N cuumn&wdue OM&ID 43 .4-1-1 be" Me 4T) %07,M ToW re&aW am (acreg L%.Uq RiecharV rwa for "mom V am (in"? RC&MV met for unparvious 7777= area (in" INPUT CALCULATIONS RMULTS Sew.1te (SaUday) CALCULATED LOADING (LB&M 3,929,1" x N-ccnc(mg/l) x 3.7851/0 x 3&Sdavs/vr: 4540DO mRAb Laam area (ag ft) 79AW.000 x OA009 lb N log ft applicad rate 3 lb/1000 sq ft x 30% leaching rate Pavement areei (Bg fo 135,601000 x O.ODD42 1b N /mg ft SIL212 Rwf me (ag ft) -2.3,760,000 xCL0D0IS1bN/wqft Natural area (&a -177,478 x 43%0 q ft/ame . OLOODDOS 1b N /*q ft 311.635 Other Sma'"s Ariculture (acrew) 47,420 x 89 The N/acre/year x 25% lead%int rate Landfills (acme) us 1184 11*N/acre/ywar I48,0w Septag, Lalowu (ItaLoya"I 1,170,0w N-ccmc (mA/1) x 3."S 1 /gal: 454000 mg/lb Animal burial (Ibelyear) x 33 % N cancentratim GOAM TOTAL NITROGEN IDA DING 1 L&SIYR) 1.914-M techarp from ww/w me Otallds TOTAL RECHARGE (MGfM 3.929,323 x 36S dayB/yr: 1,000,ODO gal/trullian gal -1.435 Total perims me taq ft) 91936-%Kmo X171ntyr/izin/ftx7.48gal/cuft:I,WD=gal/nWliongaJ To"Am -,.=Oq N x34tn/yr /12in/ftx7.48 ital/cuft: LRF-WDW/millian gal 5.149 24Z967,7W Landfills (eq f0 /fix 7.48 RaJ/cv ft: 1.605.0%) W/miWan gal 81 5,445,0W TOTAL RECHARCE (MCAUYR) nxi" TOTAL NITROGEN LOADITUTAL RECHARGE X 451,000 MC/LB: 3,785,000 L/ MCAL I PEOiARCENffROGENCONCENTRAnoN(vtg4wppuUI 2-0 PREPARED BY HORSLEY WITTEN HEGEMANN, INC Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-9 INFUTFACTORS TaMe Ni- g Loscling CAlculatimm NordL&oq*on ExIod" of Ravideadd wAts 6,IB3 Sewage flow par havan (Balfday) W cowarmuntainswumerid lavad facraml 1 960 CAn64tmL savrap flow per wra 1 423 N4xw- in --w efflumt tang1l) 1 40 Lawn am Pair house (square imb I S,000 Famnsitt Pair havot (SROM fee" I Sao 777= ROW ax,am (Npuww low r- 109,11i'm Rood aram Par house (square ind I I'm 777= A$ncmltwW area (acreal 20,S70 Idloon savis dud am fardli" I ,Afill, (&CreW 75 Septep Iw- (PlIcats" 0 77777= Septage N conciamaidw tvngn) 1 45 Aninial ba" Obs tyr) 0 Total rodumSe am (&a4W 94"7 [email protected] Rachm" rave ft pervious 17 - - - am (Lo0yr) PAwhwp mat for unpervious 34 ana UrJyr) INPUT CALCULATIONS RESULTS Sewage (gal/day) CALCULATED LOADING (LBSPYR) 1,267,915 XN-cmc(mg/I)x @851/[email protected]/yr:454=tng/lb 142.147 Lawn was (eq Ill 30,915,ODD x ODOM lb N /ag it 27,U4 applicAmon rate 3 lb/1000 sq ft x 30% ltaddng rate 1=209,300 .0.000421bN/aqft 47,1n Roof arta (ag tt) 9=4,SW xQ01001S1bN/aqft -Natural area (acr.W 6913" [email protected]/aaex Q00000SIbN/agh 15,107 Other SMINIM Algriculture (wes? 2U70 -x 79 lbs N/aae x 25% leachinIt rate 406,2m Landhila (acres) 78 1184 The N /Kre/year 12 -m Septage LmSoom (galtyeas) 0 x N-aDw(mg/1) x 3MI/gal:4SWWmjt/lb 0 AnwW burial [email protected]) _ 0 x 3.3 % N cancmirsuan 0 TOTAL NITROCER -LOADING ILBSIYR) 73Z206 TcyrALRECHARCE(MWM- techam hvm ptage (ftaL/dav) 1,167,815 x 365 doys/yr: LOW.= gal/vullion A&I 426 P-- - (.q ft) 3,968,73"W x 17 Wyr /12 irk/ft x 7.48 gal /Cu ft: I'Maw 4LO56 Total unpemous was (ag it) Without Landfilts x34tn/vr /121n/ftx7.48 gal/cu ft: 1,000,WD 4009 141.957,000 Landfills (*9 ft) x 24 in/yr /12 in/ft; 7.48 gal /cu ft: I,W0.0W [email protected],680 TOTAL RECIiARGE (MCAUYR) TOTALNrMOCEN LOAD/70TAL RECHARGE X 454,000 MG/L5: 3,76b,MU Ll MGAL I -RECHARGE NITROGEN CONCENTRATION fv*l or PREPARED BY HORSLEY WITTEN HEGEMANN, INC Ground W ater Supply Protection and Management Plan for the Eastern Shore of Virginia 8-10 E)(ISTING WATER QUALITY TESTING RESULTS The following section summarizes four studies or data bases which include test results for nitrogen content. These sources were researched in order to determine the extent of nitrate-nitrogen present in wells The majority of wells sampled, show low nitrate concentrations, although several results show very high nitrogen values that are probably related to a specific high nitrogen loading source. Virginia Department of Health, Public Water System Inventory The Virginia Department of Health tests public water supply wells regularly for several contaminants. The facilities included in this inventory fall under the categories of community, non-community, and non-transient non-community water supplies. Sample analysis dates generally fall within the years 1988 to 1990. The Table 8-7 is a synopsis of the information obtained from the VDH data base. In general, the nitrate concentrations from these samples are low, especially in Northampton County. In Accomack County, three facilities had samples which tested above 5 mg/l. Four readings taken for a Town of Parksley well had nitrate nitrogen levels of 6.6, 6.9, 5.65, and 6.2 mg/l. A NASA facility, Charles G. Ward Building F-16, registered the highest nitrate levels of the testing group. Eight samples from that facility ranged between 7.27 and 11.5 mg/l. Finally, a well at Stoney Point Decoys was measured to have a nitrate nitrogen concentration of 7.11 mg/l. Most of these wells draw water from the deeper confined aquifer where nitrogen concentrations are expected to be very low. The higher readings reflected in this data base are probably the result of influences from the shallow aquifer system. Table 8 -7: Virginia Department of Health Public Water Test Results Average Nitrate- Accomack CQmnly Northampton CouM Nitrogen concentration 1.27 mg/I 0.04 mg/I Range, Nitrate- 0.01-11.5 mg/l 0.01-1.63 mg/l Nitrogen concentration Number of samples 92 31 Number of facilities 24 11 Number of samples above 5.0 mg/I N03 13 0 Number of samples above 10.0 mg/I N03 3 0 State Water Control Board, EPA STORET Database The EPA maintains a database which contains a summary of ground water test results for public water supplies. This information is available to all states. Due to budget limitations, recent data has not been entered into the system, and the available information includes results from the late 1970's to late Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-11 1980's. Again, nitrate-nitrogen levels were low on average. Out of approximately 500 wells in Accomack and 150 in Northampton, only seven (7) wells reported nitrate-nitrogen levels above 5.00 mg/l. Table 8-8 summarizes results for the wells which tested high. Most wells which tested high for nitrate-nitrogen are shallow; therefore they draw water from the unconfined Columbia aquifer. The one exception is the town of Parksley Well #1, which has a screen depth of 160 feet. In the Virginia Department of Health database, as described above, Parksley also reported high nitrate-nitrogen levels. The results from these two sources may be cause for further investigation into the quality of the drinking water supply for the town of Parksley. Observation Well #103A is located on Church Neck, an area devoted mainly to agricultural practices (as delineated in the Northampton County Comprehensive Plan, 1990). The high nitrate levels here may indicate a correlation between fertilizer use and elevated nitrate-nitrogen levels in the ground water. However, the majority of wells in the two counties showed no contamination and it is likely that many were likewise located in agricultural areas. Table 8-8: Nitrate-Nitrogen Levels Above 5 mg/I in STORET (EPA) File, Accomack and Northampton Counties Facility Date sampled Nitrate -nitrogen Screen Depth Accomack County level (mg/1) (Feet) Town of 6/27/77 8.00 160 Parksley #1 11/14/77 6.50 2/23/78 6.00 Town of 12/9/74 8.50 64 Parksley #2 Observation 2/13/80 9.50 40,30,40 Well #114S 2/13/80 10.00 2/13/80 10-00 7/9/84 7.00 Atlantic Fire 8/4/81 5.00 69,63,69 House Northampton County Observation 9/28/77 13.00 40,27,37 Well #103A 9/28/77 11.00 5/11/79 17.60 6/26/84 24.00 Observation 10/3/77 6.90 36,26,36 Well #104S 10/3/77 6.90 8/18/80 7.50 8/19/80 9.00 8/4/86 8.25 Brown &Root 12/1/77 17.00 20,40 S710-5 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-12 Virginia Department of Health, Eastern Shore Health District The Eastern Shore Health District conducted a shallow well baseline monitoring project in April of 1990. The testing was done in response to studies completed by the United States Geological Survey which indicate that wells installed at shallow depths may be at risk of having high levels of nitrates and pesticides. The Health Department intends to confirm or deny these results, and if necessary, change regulations to prohibit the use of water supplies proven to be at risk. The written report of the baseline study is not yet available. Lab results were obtained, and are summarized below in Table 8-9. Present information available does not include the location of sampling sites. Twelve samples were taken in Accomack County, and ten in Northampton County. Wells sampled were domestic drinking wells drilled to a depth of 30 to 50 feet. Table 8-9: Eastern Shore Health District, Shallow Well Monitoring Results Accomack County Northampton CounW Average Nitrate-nitrogen concentration 1.11 mg/l 4.36 mg/l Number of samples 12 10 Number of samples above 5.0 mg/l N03 1 4 Number of samples above 10.0 mg1l N03 0 2 Average concentrations for nitrate nitrogen were much higher in Northampton County in this study than in the deeper wells in the county tested by the state. Although the sample size was small for this monitoring project, some of the levels of nitrogen were high, and the test should serve as a warning for residents with wells dug in the shallow aquifer. With knowledge of the locations of these sites, origins of the nitrate-nitrogen (agriculture, septic tanks, etc.) could be better determined and assessed. Two types of pesticides, triazines and carbanates, were tested, and none were detected in the 22 samples. A baseline study of deeper wells was also conducted by the Eastern Shore Health District. At the time of publication of this report, no information about the baseline study has been made available. This Ground Water Management and Protection Plan is primarily concerned with large withdrawals from and preservation of the deeper Yorktown-Eastover aquifer. However, studies of the kind that the Eastern Shore Health District has conducted are invaluable as documentation for future use and for the determination of present contamination which may reach the lower aquifers at a later date. USGS Water Quality Sampling The United States Geological Survey is currently involved in a water quality study of shallow wells on the Delmarva Peninsula as a continuation of a water quality analysis through 1987 (USGS Open File Report 89-34). Table 8-10 presents the unpublished results of nitrate-nitrogen levels along two transects, and isolated locations along the mainland. Samples have been taken from August 1988 to Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-13 Table 8-10- USGS Nitrogen Sampling Sample Sample Sample Sample Sample Sample ID Lai LwM Depth Date-1 N03-N Date-2 N03-N Date-3 N03-N Dale-4 N03-N Date-5 N03-N Date-6 N03-N Creek-Up 371151 755725 0.0 Jun-90 4.70 Creek-Dn 371147 755700 0.0 Jun-90 5.30 Nov-90 4.80 Well 1 3711451 755659 6.61 Jun-90 14.00, Nov-90 13.00 Well 2 371143 755658 8.9 Jun-90 6.601 Nov-90 13.00 Well 4A 371125 755702 16.8 Aug-88 9.70 Dec-88 10.00 Jun-89 9.60 Well 4B 371125 755702 26.0 Aug-88 9.60 Jun-89 9.20 Nov-90 9.60 Well 4C 371125 755702 41.5 Au-g--881 9.20 Nov-901 7.10 Well 4D 1 371125 755702 61.5 Aug-881 0.37 Jun-89 Nov-90 0.10 Well 4E 371125 755702 16.8 Nov-90 19.00 Nov-90 6.20 Well SA 371121 755650 [email protected] Aug-88 8.90 Dec-88 10.00 Jun-89 8.901 Well 5B 371121 755650 28.0 Aug-88 31.00 Nov-90 10.00. Well 6 371128, 755721 15.0 Dec-88 34.00 Jun-89 29.00 Well 7A 371136 755802 12.0 Aug-88 9.10 Dec-88. 9.40 Jun-89 15.00 Well 7B 371136 755802 31.0 Aug-881 3.50 Jun-89 2.60 Well 8 371136 755748 12.0 1 Dec-881 18.00 Well 11 1 371301 755844 13.0 Aug-88 12.00 Aug-89 7.80 Well 12 3713021 755832 13.0 Aug-88 38.00 Well 13 3711181 755635 6.6 Aug-88 0.10 Dec-88 0.151 Jun-89 0.10 ,a Well 14 371117 755631 6.7, Aug-88 0.10 E, N AC 201D 375744 753536 42.0 Sep-89 - AC 204S 375535 753249 22.5 Sep-89 0.13 AC 204D 375535 753249 48.5 Sep-89 0.10 AC 205S 375552, 753018 22.0 Sep-89 9.60 753444 36.0 Jan-90 0 SOW 110S 3757231 .10 P32 D 373049 7.54841 30.0 Aug-88 11.00 P32 S 373049 754841 22.0 Aug-88 9.20 P31 D 373330 754946 40.0 Aug-88 [email protected] P31 S 373330 754946 13.0 Aug-88. 15.00 P31AD 373916, 754108 30.0 Aug-881 6.20 P31AS 3739161 754108 13.2 Aug-88 8.10 02. P30 D 3747551 753710 28.0 Aug-88 0.10 Au -88 P30 S 3747551 7537101 15.0 in 0.291 November 1990. The depth of the wells range from 6.6 to 61.5 feet. Nitrate-nitrogen levels are generally high. Out of a total of 51 samples, 69% of them have nitrate-nitrogen levels of 5 mg/l or greater, and 31% are greater than or equal to the recommended limit of 10 mg/l. The average of all the samples is 9.2 mg/l, with the highest reading at 38.0 mg/l. The nitrate-nitrogen levels here are on average much higher than in the three studies previously described. Again, full analysis cannot be conducted because the USGS report has not yet been published. NITROGEN LOADING ANALYSIS UNDER FUTURE BUILDOUT CONDMONS A nitrogen loading analysis was conducted in the spine recharge area of each of the five wellhead protection areas (WPA's) under permitted pumping conditions. This was done to predict the future nitrogen concentration in the ground water which can be expected if the land area in the spine is built out under the current regulations. A summary of the results of this analysis are presented in Table 8-11. The more detailed computer spreadsheets per area can be found in Appendix F. The nitrogen loading analysis indicates that the nitrogen concentrations in all but one WPA exceed the EPA drinking water standard of 10 mg/l nitrate-nitrogen. Table 8-11: Nitrogen Concentration By Wellhead Protection Area Wellhead Predicted Average Protection area Nitrogen Concentration (mg/1) A, all soils 5.6 A, w/o Arapahoe soils 5.5 B, all soils 13.5 B, w/o Arapahoe soils 13.5 C 8.3 D 7.8 E 7.1 A breakdown of the nitrogen loading by source and WPA are presented in Table 8-12. The major sources of nitrogen vary depending upon the land use in that area. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-15 Table 8-12.- Nitrogen Loading Under Future Buildout Conditions In Spine Of Wellhead Protection Areas Per Source (Percent of Total) Wellhead Protection load from load from load from load from load from TOTAL Area sewage lawns agriculture landfills animal burial A, all soils 20 4 65 0 10 99 A, w/o Arapahoe soils 5 0 83 0 10 98 B, all soils 20 2 16 58 3 99 B, w/o Arapahoe soils 20 2 16 58 3 99 C 67 12 14 0 5 98 D 69 14 9 0 6 98 E 77 17 4 0 0 98 Note: pavement, roofs, natural area and septage lagoons were left off this summary table because these sources contributed less than one percent of the total nitrogen load The main sources of nitrogen under future buildout conditions are residential and commercial sewage, agriculture, and chicken burial. The actual percentage that these sources contribute vary by WPA. In those WPA's where composting of dead chickens occurs, it can be a significant source of nitrogen, up to 10% of the total load. Agriculture contributes between 4 and 83 percent of the nitrogen load depending on the wellhead area. The landfill located within in the spine of WPA B is predicted to contribute 58 percent of the nitrogen concentration under future buildout conditions in this wellhead protection area. This analysis demonstrates that a landfill located on the spine recharge area has the potential to have a significant effect on water quality, assuming that the landfill is unlined. In WPA E, in Northampton County residential sewage is the main source of nitrogen, comprising 77 percent of the nitrogen load. Sewage is the main source of nitrogen in this area because there are no poultry farms in Northampton County, and under future buildout conditions, the agriculturally zoned area can be completely subdivided into house lots, which was the scenario tested in this buildout. Considering the low residential growth rate and the current high level of agriculture, this may be an unlikely scenario. Nitrogen loading scenarios discounting soils poorly suited to development (Arapahoe) were analyzed for northern Accomack County. Though the overall loading of nitrogen does not change, the major contributor (agriculture) increases from 65% to 83% when residential development is lowered. Thus, if agriculture is a more dominant land use in the future than residential development, nitrogen loading from farn-ting will become the most significant contributor of this contaminant. The future nitrogen loading results indicate that, nitrogen concentrations in the shallow Columbia aquifer are expected to increase to levels approaching the drinking water standard of 10 mg/l. In WPA B the concentration is expected to exceed this value (13.5 mg/D. Since these values are average recharge concentrations, individual measurements of ground water quality will most likely result in much higher concentrations at locations near major sources of nitrogen use or loading. The landfill located in WPA B should be assessed in more detail to determine its potential impact on water quality and -nitrogen loading. In addition, the implementation of agricultural nutrient management plans will help to lower the average nitrogen concentration in the ground water. Other than sewering, little can be done to reduce the load from septic systems. Guiding Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-16 development and sanitary wastewater discharges away from the spine recharge will help to reduce the nitrogen load from this source. As the area develops and more residential units are constructed, loading from lawns is expected to increase. Public education on the proper use of lawn fertilizers is the major mechanism to control this potential source of nitrogen. These results indicate that under current conditions, nitrogen values in the ground water on the average are very good due to the large amounts of open and forested land found on the Eastern Shore. In addition, nitrogen concentrations in the vicinity of agricultural operations can be expected to be higher than background levels. More water quality testing and analysis in the Columbia aquifer is needed to obtain a better representation of water quality and how it changes across the Eastern Shore. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 8-17 I I I I I I CASE STUDIES 9 1 1 1 1 1 1 1 1 1 1 1 I I SECTION 9: CASE STUDIES AND THEIR APPLICABILITY TO THE EASTERN SHORE OF VIRGINIA This section describes a range of regulatory, non-regulatory, and legislative strategies which have been shown to be successful in protecting ground and surface water supplies in other parts of the United States. The case studies selected illustrate several different water resource protection strategies which may potentially benefit the Eastern Shore's efforts to protect its surface and ground waters. AGRICULTURAL PRACTICES Lancaster County, Pennsylvania: Fertilizer Effects on Water Quality Lancaster County, Pennsylvania is an agricultural area located south and west of Philadelphia. The current technology, econon-dc incentives, and social structure have led to a focus on dairy, livestock, and poultry production. Like the Eastern Shore of Virginia, Lancaster County covers a small percentage of the state (5%), but ranks high in agricultural production. In fact, Lancaster County raises 15.5% of the dairy cows in the state, 38.5% of the swine, 14% of the beef animals, 39% of the broilers, 48.75% of the laying hens, and 5.8% of the sheep. Manure disposal and excessive use of fertilizers pose a pollution problem to surface and ground water sources and to the Chesapeake Bay via outflow of the Susquehanna River. A study was done by the USGS to detern-dne the nutrient contents in two waterways, the Conestoga Headwaters and the West Branch of the Susquehanna River. The Conestoga River watershed has deep, well drained soils that are derived from limestone. The land is fertile and supports corn and alfalfa crops as well as some tobacco, soybeans, and vegetables. The West Branch of the Susquehanna, used as a control, drains lands from northern Pennsylvania where more land remains as forest and less intensive agriculture takes place. The results of the study are shown below. Table 9-1: Sampling Results in Two Pennsylvania Rivers Parameter Conestoga W. Branch (kg/ha) 1986 1985 Total P 1.8 0.13 Total N 38.9 5.2 Suspgnded Sediment 877 100 In a separate study, soil samples were taken at various depths from highly manured fields in 1982, 1984, and 1985. Access to the fields was obtained by adult education leaders working with farmers who were concerned about effects of their farn-dng practices on ground water quality and ultimately the Chesapeake Bay. The results showed that many fields contained enough nitrate-nitrogen at the end of the growing season to produce another crop of field corn. While some of the nutrient will remain in the rooting zone for the next growing season, an unknown amount of nitrate-nitrogen will move with water and percolate through the soil profile. Ground water wells in Lancaster County were sampled in 1982 and 1983 for nitrogen amounts. It was determined that in agricultural areas, 41 to 67% of the well samples had nitrate-nitrogen Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-1 concentrations exceeding 10 mg/l. Comparatively, in non-agricultural areas in the county only 9 to 27% of the wells measured above 10 mg/l. Given the elevated nitrogen levels in both the wells and the Conestoga River, and the over- fertilization of the crop lands, it was concluded that the fertilization practices played a role in the degradation of the water supplies. As a result of this study, measures have been taken to reduce the amounts of nutrients moving to water sources. Beginning in 1988, crop-available nitrogen was calculated using previous nitrogen mineralization rates plus 25% of that amount. Therefore 45% of the manure nitrogen would be calculated as available nitrogen, reducing the need for inorganic fertilizer to 10 kg N/ha. These changes have been incorporated into a computerized expert system which aims to increase the nitrogen mineralization rates and includes all other management factors that are listed in the Manure Management Manual. The next step in the study is to implement a soil and crop monitoring program to see if residual nitrate-nitrogen levels drop. Other water quality protection techniques include crop rotation, which can help control soil erosion and reduce the nutrient loading to the soils. A series of legume crops will build the nitrogen levels in the soil, and a succeeding corn crop then requires fewer nutrient additives. Manures can supply the nutrients for a second year of corn and small grains. The crop rotation schedule W, A, A, A, A, C, C, where W=wheat, small grains, soybeans; A= alfalfa; C=corn, is a desirable and beneficial schedule in Pennsylvania where part-time farm operators can use manure to fertilize their corn crops which will in turn provide food for the livestock. Source: Baker, Dale E. and Donald M. Crider, "The Environmental Consequences of Agriculture in Pennsylvania". In Majumdar, S.K., Miller, E.W., and Parizek, R.R., eds. Water Resources in Pennsylvania. Easton, PA: The Pennsylvania Academy of Science, 1990. Pages 334-353. General Applicability to the Eastern Shore of Virginia Lancaster County differs from the Eastern Shore in many respects. The topography is more hilly, livestock is an intense industry, and even the cultural practices of Arrdsh and Mennonite peoples raise issues that would not be applicable to Accomack and Northampton Counties. This case study identifies the negative aspects of agriculture, and in particular the over-application of animal waste products. The situations presented in this case study are not found on the Eastern Shore, where most of the farmers are very concerned about water quality impacts from agricultural activities. However, the example serves to document the relationship between agriculture and water quality. Although conditions may vary nationwide, the issue of fertilization and its influence on ground water quality is becoming better understood. In fact, a report in California stated, "nitrate has accumulated in ground water to the degree that farmers reportedly no longer need apply fertilizer to satisfy crop needs" (Ground Water Pollution News, 1989). This case study has general applicability to the Eastern Shore in controlling nitrogen loading from agriculture by incorporating frequent soil testing to determine the residual nitrogen that is available in the soil for uptake by a new crop. Cooperative extension agents could institute soil testing programs to track residual nitrogen levels in soils and help farmers better calculate fertilizer additions necessary to meet crop production requirements. Until 1990 soil testing was a service provided by the state at no cost to farmers and homeowners of Virginia for assuring water quality. In past years, approximately 98% of Eastern Shore farmers utilized this service. The service is no longer free and a fee is charged. Preliminary data indicates that the number of Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-2 samples submitted for analysis under the fee system has declined by 67%. Nutrient management is a practice that is well established on the Eastern Shore and should continue to be a major focus for the protection of water quality. Jefferson County, Wisconsin: Controlling Disposal of Livestock Wastes Jefferson County is an agricultural county located in southeastern Wisconsin. Homes, farms, and businesses generally depend on ground water for their water supplim The county was concerned that there was no regulatory procedure for determining the impacts to water quality from the intensive agricultural activities occurring within wellhead protection areas (WHPA's). The primary issue centered on the use and disposal of animal wastes. Rainwater percolates through tons of manure generated by feedlot operations annually (stored unconverted) and then infiltrates into the ground, carrying high concentrations of nutrients. Manure applied as fertilizer contributed to elevated nitrogen levels in ground and surface waters. The county developed a zoning ordinance which required a conditional use permit for feedlots larger than a threshold size of 35 acres and possessing a minimum of 150 livestock units 0 livestock unit is equivalent to 1000 pounds live anirrul weight). Adopted in 1975, the ordinance's permit application required that the proponent provide background water quality data, particularly for bacteria and nutrient concentrations; rates and timing of manure applications; and existing nutrient levels in the soils. The county did not aggressively implement the ordinance until 1980 following complaints from some of the county's 60,000 residents about the odor resulting from the feedlots, especially poultry feedlots. The county then moved to prohibit feedlot operations on lots smaller than 35 acres in size, which were seen to be a significant source of pollutant loading. The county is currently preparing an ordinance which will regulate the design and siting of a manure containment facility for lots above threshold limits. According to county officials, implementation has been difficult given the limited staff size of four for the entire county. The ordinance does not control the use of inorganic fertilizers, which are becon-dng more popular as a reaction to the stricter controls on animal manure applications. General Applicability to the Eastern Shore of irginia Agricultural practices have been often cited as major non-point sources of ground and surface water pollution. Given the large areas of existing and zoned agricultural land uses on the Eastern Shore, this case study provides an appropriate example of agricultural land use controls. In particular, Accomack County may require development of similar ground water protection mechanisms which would control the uses of animal wastes and inorganic fertilizers within particularly vulnerable water resource protection areas from poultry wastes and set up a reporting and monitoring system. Specific implementation recommendations from Jefferson County can be readily applied throughout the Eastern Shore to control nitrogen leaching from poultry waste. For More Information Mr. Bruce Houkum, Zoning Administrator, Jefferson County, Wisconsin, (414) 674-2500. Mr. Gordon Stevenson, Project Officer, Animal Wastes Management Office, Department of Natural Resources, Madison, Wisconsin, (608) 267-9306. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-3 Delmarva Peninsula: Composting Chickens The poultry industry is currently enjoying a good economy. However, the problem of disposing of dead birds that never reach the factory is affecting the industry as a whole. Traditional methods of disposal, which include burial (risk of ground water contan-tination), incineration, deposition in the woods, and feeding dead chickens to hogs and other chickens (rendering) are health hazards and may also be illegal. However, a natural mortality rate that ranges from 0.1% to 8% can be expected in a flock which takes 45 days to raise. The Delmarva Peninsula, in particular, has a fragile ecology and chicken growers must be concerned with causing further contamination to the Chesapeake Bay. Dr. Dennis Murphy, a member of the faculty at the Department of Poultry Science at University of Maryland at College Park, has developed a method for disposing of dead poultry by composting. The idea of composting is itself not a new idea, but Dr. Murphy has applied it to the poultry industry such that it can handle the volumes of chickens in an inexpensive and environmentally sound way, and is not a health hazard. The process of composting involves nitrogenous materials (in this case, manure and dead birds) and carboniferous material (cellulose paper, sawdust, or straw stover). These ingredients are converted to hun-dc acids, bacterial biomass, and organic residue with the action of aerobic, thermophilic, spore-forn-dng bacilli. Heat, carbon dioxide, and water vapor are all generated as byproducts. In order to compost, the chicken grower must construct a composting structure. The facility can vary in many ways but it must have a roof, an impervious weight-bearing foundation such as concrete, and rot-resistant building materials. These requirements allow for year-round use, prevent contan-tination to surrounding areas, and help control the amount of moisture that goes into the system. To begin the composting process, a bin is filled with several sequential layers of straw, chickens, and manure, the proportions of which have been detern-dned by Murphy. Within two to four days of loading, the temperature within the bin should increase rapidly and reach a peak of 135-150'F. The chickens are effectively cooked, and pathogens are killed in conditions above 130*F. After ten days, the temperature drops. The contents of the bin are then removed with a front-end loader and stored in a second bin. The action of transferring the contents to a new location aerates the n-dxture, and in the secondary bin, the temperature rises again. Only two stages are needed, and within a matter of weeks, the chicken carcasses become compost material of similar texture to that of organic soil. The process is virtually odorless, according to Murphy. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-4 Figure 9-1 Scheme of Simple Poultry Composter - 8 fL Wkw - C> C> 4- MWWM P-Abry U3 sftw C> C> Cn. menu= . ......................... C> Source: University of Maryland Cooperative Extension Service, Fact Sheet 537 The temperature of the chicken/manure/straw composition must be monitored during composting in order to assure that everything is going properly. Murphy estimates that the normal daily operation of a composter designed to handle 1,050 lbs. of carcasses per day requires twenty minutes. This estimate includes all activities, such as loading, monitoring temperatures, adding water, and moving compost. The cost of running a composter is 03 Ob. spread over a ten year depreciation schedule. By comparison, incineration costs 3-80b. over a five year schedule. One grower in Maryland has begun selling the composted chickens as a soil conditioner and enricher. The resulting compost is an excellent mild fertilizer. A five-county poultry region in southwest Missouri is launching a demonstration project that will dispose of dead birds by a composting process. In 1987, the region had a poultry population of 33 million broilers, 10 million turkeys, and 4 million layers. The objective is to compost two million dead birds from the area annually. The Missouri State Committee of the Agricultural Stabilization and Conservation Service has approved the composter for Agricultural Conservation Payment (ACP) cost-sharing. Hopefully more states will create incentives for composting via the cost-share program. In short, composting chickens is a simple and economic method of disposing dead birds. It does not contribute to ground water contamination, and creates a salable product. General A1212licabilily to the Eastern Shore of Virginia Several growers on the Delmarva Peninsula already employ the composting method to reuse and recycle waste products from the chicken raising industry. Chicken growers should seek assistance from County Extension Agents and the Cooperative Extension Service on methods, materials, and cost to compost chickens. Composting can create a valuable product that can be used as a mild fertilizer and soil conditioner. For More Information Dr. Dennis W. Murphy, Cooperative Extension Service, Route 2, Box 229-A, Princess-Anne, Maryland, 21853, (301) 651-9111. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-5 ON-SITE WASTE DISPOSAL Ontario, Canada: Nitrogen Plumes from Septic Systems One-third of the population of North America uses septic systems for disposing of liquid wastes. This practice accounts for the largest volumetric source of effluent discharged into the ground water zone. Septic systems located on sand and gravel aquifers are a potential source for producing large- scale contaminant plumes in aquifers that are also likely to be used for the drinking water supply. Robertson, Cherry, and Sudicky (1990) used ground water monitoring networks to investigate ground water impacts caused by septic systems at two single-family homes in Ontario. The homes were located on shallow, unconfined aquifers. Several water-table piezometers were installed, and sediment cores were sampled continuously. The older site, at Cambridge, had a septic system in operation since 1977. The field investigation started in 1987. The younger site was located at Muskoka, and was monitored six months after the beginning of full-time use in 1987. Both septic systems were of the conventional design used in Canada and the U.S. for permeable soils. The tests yielded several results. The plume shape at the Cambridge site demonstrated that the flow within the aquifer was predominantly horizontal except beneath the tile bed where the plume followed a vertical path such that it nearly reached the bottom of the aquifer. Using a bron-dde tracer, average tank residence time was found to be two days. In Cambridge, effluent residence time in the 2-m-thick unsaturated zone was 10 days, whereas at Muskoka, the bromide tracer experienced a longer residence time in the 3-m-thick unsaturated zone at this site, in the order of several weeks to months. Flow velocities were calculated at both sites. Nitrogen in septic systems is about eighty percent (80%) inorganic, predominantly ammonium [NH4+-N]. At both sites, tile effluent concentrations for NH4+-N ranged from 30-59 mg/I and nitrate-nitrogen [N03--N] concentrations from 0.1-1.0 mg/l. Comparatively, plume core chen-dstry revealed almost the opposite concentrations, with NH4+-N concentrations at 0.1-0.5 mg/1 and N03--N at 33-39 mg/l. This suggested that the ammonium in the effluent was being oxidized via n-dcrobial nitrification, as in the following equation: NH4 + + 202 --> N03- + 2H+ + H2 Low dissolved oxygen content levels and high nitrate-nitrogen levels observed even in the shallowest water table zone below the tile fields indicated that the processes in the above equation are largely completed during residency in the unsaturated zone, but also continue below the water table. A three-dimensional analytical model was used to obtain estimates of the aquifer dispersion parameters within the saturated zone. Modeling results indicated that transverse dispersion rates at both sites were low. The detailed findings were significant in that they were consistent with very detailed tracer tests recently performed at Twin Lakes, Ontario and Cape Cod, Massachusetts. At the Cambridge site, which had been in operation for twelve years, the plume had sharp lateral and vertical boundaries, and was more than 130 meters (427 ft) in length and had a uniform width of about 10 meters. After 1.5 years of use, the Muskoka plume began discharging to a river located 20 meters (66 ft) from the tile field. At the organic-rich riverbed, denitrification, or nitrate attenuation, occurred such that little nitrate-nitrogen was actually discharged into the stream. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-6 The model was employed to make nitrate-nitrogen predictions at the Cambridge site. Using the transn-tissivity rates at Cambridge, a source concentration of 33 mg/I N03--N, and a background level of zero nitrate, the steady state plume length which would exceed the drinking water standard of 10 mg/l N03--N is 170 m (558 ft). The authors use their study to issue the following warning, "Therefore, for many unconfined sand aquifers, the minimum distance-to-well regulations for permitting septic systems in most parts of North America should not be expected to be adequately protective of well-water quality in situations where mobile contaminants such as N03- are not attenuated by chemical or microbiological processes." Source: Robertson, W.D., Cherry, J.A., and Sudicky, E.A., "Ground-Water Contamination from Two Small Septic Systems on Sand Aquifers", Ground Water, January-February, 1991, p. 82-92. General Applicability to the Eastern Shore of Virginia This recent study presents important information for Eastern Shore residents. In areas where septic systems are dense and people rely upon private wells screened in the shallow aquifer, nitrogen levels can be expected to be 10 mg/I at close to 600 feet from the septic system. On the Eastern Shore, proper well spacing from septic systems may require a setback of up to 600 feet due to the very sandy soils, and shallow depth to the water table. Falmouth, Massachusetts: Performance Standards Within Zones of Contribution Falmouth is a coastal town on Cape Cod, Massachusetts. The town typically experiences a large increase in population during the summer months with the influx of seasonal residents. The town's water supply, however, is limited to its aquifers which are part of the Cape Cod sole source aquifer. With the residential development boom of the early to mid 1980's, large amounts of previously undeveloped areas were subdivided and developed for residential and commercial use. The higher residential density and greater numbers of on-site sewage disposal systems began to affect ground water quality, particularly by raising nutrient concentrations in ground waters. The situation was severely aggravated after a 500,000 gpd public water supply was forced to close because discharges from an upgradient sewage treatment plant had contaminated the aquifer. Serious concerns were raised about the main water supply, which was located downgradient of the town landfill, a sewage treatment plant, an industrial park, and extensive residential development. Worse still, the town's zoning allowed for a saturation build-out population three times that of the present. In short, existing and programmed land uses seriously threatened the town's ground water supplies. In response to these concerns about existing and potential water supply contamination, the town delineated the zones of contribution and associated recharge areas for all drinking water supplies and surface water bodies. After identifying priority protection areas, the town developed and adopted a set of performance standards together with a methodology for determining cumulative loading impacts to ground water quality. The standards essentially limited further development within a zone of contribution or surface watershed if the added nutrient loading from the land use would increase the ground or surface water concentrations of those nutrients past certain thresholds. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-7 In order to accommodate already planned developments within the Ground and Surface Water Resource Districts, the town adopted a transfer of development rights program, which was expected to encourage development outside of the delineated zones of contribution and surface watersheds. General A1212licability to the Eastern Shore of Virginia Nutrient management by performance standards has been shown to be an effective and defensible method of managing development within vulnerable ground water recharge areas. Our nutrient loading analysis indicates that nitrogen loading performance standards should be adopted and enforced at some point in the future on the Eastern Shore. Saturation build-out would generate significant increases in ground water nitrogen concentrations given the potential programmed increase in associated loadings from septic systems, lawn and farm fertilizers, roadway and parking lot runoff, etc. By devising nitrogen loading performance standards for development located within the recharge areas, the Counties may successfully prevent contarnination of their drinking water supplies from nitrogen. Specific control over nitrogen is more appropriate for the shallow water table aquifer than for the deeper aquifers used for drinking and industrial water use. For More Information Victoria Lowell, Barnstable County Comn-dssioner, (508) 362-3828. Long Island, New York: Restrictions Within Recharge Zones The Long Island Regional Planning Board has been working on ground water protection issues for the two counties of Nassau and Suffolk for several decades. Originally, primary issues of concern revolved around ground water quantity and the potential for salt water intrusion. More recently there has been a focus on ground water quality concerns. Studies such as the regional 208 wastewater study, published in 1978, pointed to the need for increased water quality protection strategies for two types of recharge zones, deep recharge and shallow recharge zones. The zones are delineated according to the distance between surface level and ground water elevation over which infiltrating rainwater travels vertically. The shallow recharge zones are typically found closer to the ocean shoreline. The deep recharge zones were seen as more critical resources because they contained much larger quantities of ground water; many were found to still contain excellent water quality. The Regional Planning Board worked with the state health agencies, water suppliers, municipalities, and counties in developing a number of land use controls to prevent water quality impacts from on-site septic systems. These waste disposal systems were considered an important source of contaminants. Conventional septic systems provide minimal treatment of wastewater. Leaching facility effluents contain approximately 40 to 60 mg/I of nitrogen. The effluents also contain high phosphorus concentrations and large numbers of pathogenic bacteria and viruses. Septic systems can also introduce hazardous wastes into the ground water if the owner uses septic cleaners or pours household hazardous wastes down the drain. The cumulative effects of many small septic systems on nutrient, pathogen, or hazardous waste levels in downgradient waters can be very significant. These impacts are dependent upon septic system location and density relative to receiving water bodies. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-8 Accordingly, several land use programs were implemented. The Regional Planning Council assisted in the development of recommended minimum lot sizes for undeveloped deep recharge areas. They recommended a n-dnimum area of two acres as a means of ensuring adequate dilution of septic system effluents within the protection district. The planning board and the counties also worked together to organize bans on the sale and use of septic system cleaners, which have been shown to be significant sources of hazardous material contan-tination. Presently, the local and regional authorities are developing septage districts and accompanying regulations which would oversee the regular pumping out of household septic systems. This can greatly improve treatment performance and reduce the opportunity for breakouts. General AR12licability to the Eastern Shore of Virginia The regular pumping of septic systems is a management technique currently being required by the Chesapeake Bay Preservation Act for the Eastern Shore. The Long Island example can be used to develop a septic system management program for this area. Potential and even existing residential development and the accompanying septic systems are a source of ground water contamination within the shallow recharge areas. By adopting similar land use controls and regulations on the siting and operation and maintenance of such systems, Accomack and Northampton Counties may be able to eliminate the possibility of nutrient and hazardous waste contan-driation in vulnerable ground water recharge areas. For More Information Ms. Edith Tannenbaum, Planning Director, Long Island Regional Planning Board, Long Island, New York, (516) 360-5189. Gloucester, Massachusetts: Siting of Septic Systems The City of Gloucester, Massachusetts recently developed ordinances governing the siting of septic systems in order to protect sensitive ground water supplies. Septic system effluent contains a large number of pathogenic bacteria and viruses. Under certain geologic conditions, the effluent may travel rapidly, reducing the potential for treatment by soil filtration and increasing the risk to human health. Much of Gloucester consists of shallow sandy sediments overlying bedrock. When a septic system leaching field is constructed in an area with shallow depths to bedrock, the effluent will quickly percolate through the sediments without receiving adequate treatment. The effluent then moves along the the bedrock surface, allowing it to quickly reach a water supply well. The City's officials, concerned over the potential threat to drinking water supplies, adopted two health ordinances governing the siting of septic systems. Any proposed sewage disposal system which lies within 600 feet of a drinking water well or a surface water body would not receive a Disposal Construction Works Permit until the proponent had submitted sufficient hydrogeologic information to demonstrate that there was a minimum travel time of 50 days between the leaching facility and the downgradient water resource. Similarly, the Board of Health would not approve the subdivision plans until the performance standard of 50 days n-dnimum travel time had been shown by the project proponent. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-9 General Applicability to the Eastern Shore of Virginia The soils on the Eastern Shore are very sandy and allow for the rapid movement of water. The shallow depth to water may also assist in the transport of viruses. The Counties should consider some form of private well/septic system ordinance to provide the maximum protective distances between these features. For More Information Board of Health, City of Gloucester, 41 Washington Street, Forbes Building Annex, Gloucester, Massachusetts, (508) 281-9771. Locations Throughout the U.S.: Constructed Wetlands, Alternative to Conventional Wastewater Treatment Constructed wetlands are defined as those systems specifically designed for wastewater treatment. They are not subject to laws and regulations involving natural wetlands, and are generally located in areas where natural wetlands did not previously exist. Constructed wetlands provide secondary wastewater treatment, advanced waste treatment, or sludge management for smaller towns, rural communities, and industrial plants. Aquatic plants and tiny n-dcrobes are used to replace costly mechanical pumps and industrial chemicals required by conventional wastewater treatment plants. Part of their popularity is due to their low cost and the simplicity of operation. The purification process is a simple one. In an initial holding tank, sludge undergoes primary treatment where the sediment settles out. Then waste water flows into pathways lined with rock and filled with emergent wetland plants. The rock is a home for bacterial slime that digests the organic wastes. Microbes on the aquatic plant roots perform a similar function. Meanwhile the plants draw nourishment from the effluent and absorbs the resulting proteins, starches, and sugars. The plants inject oxygen into the water to nourish the bacteria, and also contribute oxygen to the air, helping to regulate the level of carbon dioxide in the environment. The wetlands typically include some type of barrier to prevent ground water contamination beneath the bed. The barriers used thus far range from compacted earth to membrane liners. Other systems are completely enclosed in a series of containers. Currently, constructed wetlands are being used throughout the country, with the greatest concentration in Tennessee, South Dakota, Louisiana, and Mississippi. The design capacities of the systems range from 10,000 gallons per day in El Dorado, New Mexico, to 20 million gallons per day in Orlando, Florida. In Anne Arundel County, Maryland, a water reclamation facility has been operational since December 1988 and handles a flow of approximately 500,000 gallons per day. The Mayo, Maryland facility is a septic tank effluent collection and treatment system, and utilizes the following components: recirculating sand filters, bulrushes (the emergent wetlands), peat wetlands, ultraviolet disinfection, and discharge through an offshore wetland into Chesapeake Bay. The system comes consistently under NPDES Permit effluent requirements for the facility. In 1988, the mountain community of Monterey, Virginia began using a constructed wetlands system built at a capital cost of only $150,000, and with operating costs a fraction of running a mechanical facility. The decision to shift its water treatment facility to a constructed wetlands was mainly an economical one. The 190 customers had an average household income of $14,000, and the community did not have the resources to cover the costs to meet new state requirements ($500,000). For this system to operate successfully, special plants had to be considered to withstand periods of sub- Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-10 freezing temperatures in the winter. Between June 1989 and June 1990, the system treated 20,000 gallons per day, and fell within discharge standards. In addition to municipal systems, the constructed wetlands have also been used at individual homes and as treatment facilities for subdivision areas. There are potential applications in agribusiness and for filtering heavy metals and toxic chemicals out of industrial effluent. For more information: NCW Systems, Inc., 5711 Staples Mill Road, Richmond, Virginia, 23228, (804) 264-7810. General Applicability to the Eastern Shore of Virginia Constructed wetlands offer a final wastewater treatment alternative that is very applicable to the Eastern Shore. Since a majority of the coastal marshes on the ocean discharge side of the Eastern Shore are in public conservation ownership, incorporating artificial wetland systems can be very appropriate for most discharge facilities. The use of these systems will allow residential and industrial development to proceed in areas where conventional surface water discharges would cause water quality effluent problems. In particular, the County of Northampton would benefit from artificial wetland systems because of the large amount of marshland that is found in the County and the high degree of final wastewater treatment that can be achieved from these systems. The low cost and simplicity of operation would also be of great value on the Eastern Shore. SURFACE WATER MANAGEMENT Chesapeake Bay Area, Maryland: Stormwater Pollutant Reduction Stormwater management is one component of the US EPA's National Estuarine Program for the Chesapeake Bay Area of Critical Concern. The tremendous increase in development activities within the Bay area has had serious impacts on the Bay's water quality. Point and non-point sources of pollution were targeted for action, beginning with limiting various land uses in the near shore areas. Stormwater was identified as one of the major non-point pollution sources to the Bay, along with agricultural practices. Runoff from roadways, parking lots, overloaded or poorly designed stormwater sewers, and poor soil conservation practices usually carries a very significant amount of pollutants, including metals, volatile organic compounds, oils and grease, nutrients, bacteria and viruses and suspended solids. Nutrients and suspended solids have been shown to cause adverse impacts to the Bay's water and habitat quality for a wide range of upper Bay organisms. Nitrogen, and to a lesser extent, phosphorus, acts to encourage the rapid growth of algae and aquatic plants, which can reduce the dissolved oxygen content of the waters. In turn, the lower oxygen content stresses or kills fish. Suspended solids from soil-laden runoff block light and harm plankton and other photosynthetic organisms. With the passage of the Bay Critical Area Law in 1985, the State of Maryland took an aggressive step forward in reducing point and non-point source pollution to the Chesapeake by restricting land uses within the watershed. Local communities were required by law to assign their lands falling within the Critical Area to one of three broad land use areas: Intensely Developed, Limited Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-11 Development, and Resource Conservation Areas. The table below describes how the Commission defined each land use category and the pollutant reduction goals set for each. Table 9-2: Pollutant Reduction Goals by Land Use Categories, State of Maryland INTENSELY LIMITED RESOURCE DEVELOPED DEVELOPMENT CONSERVATION Characteristics Dense residential Mixed land usage: Primarily open fields, institutional, com- not dominated by wetlands, forest, and mercial, or indus- wetlands, agriculture, agriculture. trial uses. forest or open space. 4 or more dwelling 1 dwelling unit per 5 Less than 1 dwelling units per acre. acres up to 4 per acre. unit per acre. Public water & sewer Areas with public No public water or serving at least 3 water, sewer or both. sewer service. dwelling units per acre. Criteria Reduce pollutant Restrict removal of Residential develop- loadings by minimum existing forest land to ment limited to overall 10% from predevelop- 20% when develop- density less than 1 ment loadings. ment occurs. dwelling unit per acre. Reduce nonpoint Restrict impervious Encourage agriculture & impacts to streams & area to 15% of land forestry. tidal waters from area being developed. redevelopment. Protect remaining Encourage clustering wildlife & fish of dwelling units to habitats. conserve natural habitats. Within intensely developed areas, such as the City of Baltimore, the Critical Area Commission has developed and implemented what it calls the 10% rule: any new development or redevelopment of a site must employ stormwater pollution control methods to ensure that the resulting pollutant loading from the new activity is at least 10% less than that from the existing land use. This rule was developed as a means of meeting the pollutant reduction criterion listed in the table above. The 10% rule procedure consists of nine steps which determine whether the proposed new development or redevelopment must comply. The procedure also estimates existing and post- development runoff rates and pollutant loadings, and compares pre- and post-development stormwater pollutant loadings to see if the latter loading is at least 10% less than the former. In essence, local jurisdictions with areas classified as Intensely Developed must evaluate each Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-12 regulated proposed development using the 10% rule to ensure that the area's overall pollution loadings from stormwater runoff are decreasing. General Applicability to the East rn Shore of Virginia Northampton County's Master Plan attempts to address the new issues associated with Virginia's Chesapeake Bay Preservation Act. Land development densities have decreased in the County as a result of the County's new ordinance. Some version of the 10% rule for new development adopted by the Chesapeake Bay Program in Maryland may be an effective mechanism for gradually but consistently achieving stormwater-related pollution reduction within intensely developed areas on the Eastern Shore. For More Information: Framework for Evaluating Compliance with the 10% Rule. Chesapeake Bay Critical Area Commission, Annapolis, Maryland, (301) 974-2426. Maryland Department of the Environment, Stormwater and Sediment Division, Mr. Vince Berg, Director, (301) 631-3553. Buzzards Bay, Massachusetts: Stormwater Treatment System Established in 1985, the US EPA/Commonwealth of Massachusetts-supported Buzzard's Bay Project was made part of the National Estuarine Project in order to protect the Bay's sensitive environmental resources. A draft Comprehensive Conservation and Management Plan (CCMP) for the project area, released in May, 1990, outlines the Buzzards' Bay environment, priority pollution problems and summarizes the project's action plans for addressing these problems. According to the CCMP, stormwater runoff comprises one of the major pollution sources to the estuary and bay. As described above for the Chesapeake Bay Critical Area, the runoff contains a wide variety of pollutants which can adversely affect the bay's water and habitat quality. Runoff from stormwater drains was identified as a priority problem because it is known to carry large quantities of fecal coliforms, viruses, metals, pesticides, and VOC's. The project identified two large stormwater drains which served two suburban areas and directly discharged runoff into the bay as sites for pilot demonstration projects in stormwater-runoff control technology. The two sites were Electric Avenue in Boume and Red Brook in Wareham. A stormwater treatment structure resembling a large septic system was constructed under the parking lot for the Electric Avenue beach. The structure serves to divert and hold runoff flows, allowing sediments and associated pollutants to settle out while the water infiltrates into the subsurface soils. The settling tanks will be emptied regularly. A ground water monitoring system was also put in place to gauge ground water quality impacts. Prelin-dnary results have shown that the system is extremely efficient in removing indicator pollutants, such as fecal coliforms, (a common indicator), by 98%. The Red Brook pilot project, now underway, will utilize infiltration ponds to hold stormwater runoff until it infiltrates into the soil. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-13 In response to the success of the Electric Avenue demonstration project, the Buzzards Bay Project is collaborating with the US Soil Conservation Service (SCS) to provide design expertise and funding for construction of similar sediment/ stormwater control devices to several project area communities. The project has also identified the importance of collaboration between various state agencies regarding construction and maintenance of roads. The Massachusetts Department of Public Works is primarily responsible for the design and construction of safe public roads. Concerns over the water quality impacts resulting from the newly constructed roads are usually only secondary in nature. DPW road projects are exempted from review by local conservation commissions. Accordingly, the CCMP has recommended that towns and the DPW work together to minimize stormwater runoff beginning at the preliminary design stage. Potential advantages include reducing the pollutant load through environmentally conscious road design and lowering mitigation construction costs by incorporating mitigation structures within the costs for road construction. General Applicability to the Eastern Shore of Virginia Stormwater runoff is not a major concern on the Eastern Shore of Virginia. However, if there develops a need for more effective management of sediment and stormwater associated pollution, the above case study may provide ideas for better management of stormwater. For More Information Buzzards Bay Comprehensive Conservation Management Plan, May 1990. Buzzards Bay Project, US EPA & Commonwealth of Massachusetts. Dave Janik, Buzzards Bay Project, 2 Spring St. Marion, Massachusetts, 02738, (508)748-3600. Chesapeake Day Area, Maryland: Vegetated Buffer Zones Maryland's 1985 Chesapeake Bay Critical Area Law required local communities to control land uses and reduce pollutant loadings on lands located within the Critical Area. It also specified the establishment of different types of buffer zones for various land uses within the Critical Area. Vegetated buffer strips offer tremendous value in protecting wetlands and surface waters from a variety of impacts for little cost. Buffer strips serve to contain and encourage infiltration of surface run-off, thereby attenuating levels of nutrients, metals, petroleum hydrocarbons, pesticides, and other pollutants. They are less expensive, outside of land costs, than technology-based stormwater control structures in both capital and operation and maintenance costs. Buffer zone and land use regulations for the Chesapeake Bay Critical Area include: 1 . Mandatory soil conservation and stormwater management plans and adoption of best management practices (BMP's) for all agricultural lands within five years. 2. 25-foot buffer zone along tidal waters and stream courses established until a soil conservation plan is implemented. 3. Livestock cannot be watered or fed within 50 feet of water's edge. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-14 4. Prohibit new development and new marinas within 100 feet of shoreline in Resource Conservation Areas. 5. Delineate a 25-foot minimum buffer zone around non-tidal wetlands. 6. Establish a 100-foot minimum naturally vegetated buffer zone around all of the Bay's non-developed areas. These requirements work not only to preserve vulnerable resource areas, but are also effective in fin-dting soil erosion. The buffer zones reduce or eliminate altogether the opportunity for direct discharges of stormwater runoff into sensitive surface waters. In addition, the buffer strips provide critical habitat for a wide range of wildlife species. General AR12licability to the Eastern Shore of Virginia Buffer strips may be important on the Eastern Shore for the protection of coastal tidal wetlands. The buffer strips themselves will act as sinks to utilize nitrogen rich ground water that may be discharging to the shallow system. The specific application of this approach to the Eastern Shore would require more research. For More Information Chesapeake Bay Critical Area Commission, Annapolis, Maryland, (301) 974-2426. HAZARDOUS MATERIALS HANDLING AND STORAGE Portland, Oregon: Land Use Controls Within Wellhead Protection Area The Columbia South Shore Aquifer, located by th6 banks of the Columbia River, was designated as a back-up water supply for the City of Portland. The aquifer lies within the boundaries of the mixed use Columbia South Shore Development Area. Concerns focused on the Wellhead Protection Area (WHPA), which had been delineated rudimentarily using roads as boundaries; the true boundaries were not yet known. The prelin-dnary WHPA and surrounding areas contained a number of different industrial land uses and there was concern that ground water could become contaminated by solvents and petroleum hydrocarbons which were stored, utilized, and produced by different industries. In response to these concerns, city and state agencies established a list of prohibited and/or controlled activities and substances. Certain land uses which involved hazardous materials were prohibited. Use of non-prohibited materials required a water quality impact review before being permitted. Additional regulations stipulated the containment requirements for the storage, use or transport of hazardous materials. Activities and land uses which were prohibited within the WHPA were broad and included uses that heretofore were allowed to exist within Wellhead and Ground Water Resource Districts. For example, gas stations were prohibited, as were all production, storage, or disposal of hazardous materials. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-15 The water quality impact reviews required for uses of non-prohibited hazardous materials were made mandatory upon request from the public or abutters. The use would be permitted only if the proponent could demonstrate that there would be no adverse impacts to ground water quality. After much research, the City developed and published containment requirements for the storage, use, or transport of hazardous materials within the City Handbook. All containment plans had to pass review by the Bureau of Buildings, which would, in turn, consult with the Water Works Department and the Envirorunental Services Bureau. General AWlicability to the Eastern Shore of VirgjnLia The Eastern Shore does not presently possess the same density and range of industrial development found in Portland's South Shore Development Area. However, this case study offers a valuable example of protecting vulnerable ground water resources without banishing already existing industries from the Water Resource Protection Districts. In this way, local and County governments avoid a potential loss in tax revenue and a potential slowdown in econon-dc growth. While the risk of ground water contan-driation from the hazardous materials has not been completely elin-dnated, the Portland approach minin-dzes that risk by only permitting the use of less hazardous materials (with regard to toxicity or quantity) within the Water Resource Protection Districts. The Portland approach could be applied in intensely developed recharge areas found along the spine of the the Shore. Dayton, Ohio; Overlay District For Aquifer Recharge Area The City of Dayton draws upon a glacial outwash aquifer primarily composed of sand and gravel for a large part of its water supply. The aquifer is very permeable and permits rapid ground water travel. However, the aquifer recharge area has already been densely developed by industry. Citizens and local and state government officials were becon-dng increasingly concerned about the threat of ground water contarridnation from the large amounts and varieties of hazardous materials used by the industries. The City delineated a 6,000-acre water resources protection overlay district based on estimated times of travel from potential sources to wells. The overlay district encompasses 550 businesses which use, handle, or store an estimated 200 million pounds of hazardous materials each year. Rather than prohibiting industrial uses or resorting to downzoning (raising minimum lot size requirements and precluding industrial development) within the aquifer protection district, the city's water department devised a hazardous material control program that emphasizes notification and reporting on the types and volumes of hazardous materials used. The Water Department administers the program. Businesses and industries located within the protection district are required to report the types and quantities of chemicals used on site. The department assigns intensity and use ratings based on the material's toxicity, threat to ground water and quantity produced, used or stored. The regulations set limits on the maximum amount of hazardous materials allowed on site. The City funds the program by applying a surcharge to Dayton residents' water bills. Companies which do not use, handle, store or generate quantities exceeding the notification threshold are considered to be "conforming". They are not allowed to subsequently apply for an increase in amount or in number of hazardous materials used on site. An enviror-anental advisory Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-16 board was established to hear petitions for the deregulation of materials; the burden of proof is left with the petitioner. The program established a rapid deployment emergency response program which included awarding a clean-up contract to a professional hazardous waste company, which is responsible for providing prompt and effective treatment and extraction of spills. An extensive inspection program was set up to prioritize problem areas and offer corrective solutions. The program's defensibility has been one of its greatest successes. According to the City of Dayton Water Department, since the program's initiation in 1987 no suits have been brought against the City regarding the program. Mr. Hall attributes this to the program's emphasis on regulating and monitoring hazardous material use without directly prohibiting uses or downzoning the district. General Applicability to the Eastern Shore of Virginia The Dayton case study, as with Portland, Oregon, focuses on a heavily industrialized and residentially developed city. The lessons learned from these two case studies are applicable to the Eastern Shore because of the need to address existing industrial and commercial development. The Dayton approach is to monitor and require record keeping for all facilities without closing them down or requiring major infrastructure changes. For More Information Mr. Dusty Hall, Water Department, City of Dayton, Ohio, (513) 443-3600. Palm Beach County, Florida: Ground Water Protection Through Zoning Ordinance Following the closure of 36 water supply wells contaminated with hazardous wastes, Palm Beach County, Florida, developed a zoning-based Wellfield Ordinance to protect its vulnerable ground water supplies. Implemented in 1988, the ordinance received strong support at public hearings and in a referendum, despite the protection area's existing residential and industrial development, and very high density. The ordinance restricts the use, storage, handling, and production of hazardous materials within the protection district. No grandfathering of existing uses was allowed. The protection district was divided into four zones based on hydrogeologic investigations and modeling. The zones were delineated as a function of proximity and extent of recharge contribution to public water supply wells. Uses and presence of hazardous materials are regulated according to the risk or threat posed to wells for each zone. All hazardous materials are prohibited in Zone 1, within which lie the most vulnerable recharge areas. In contrast, businesses and industries can use hazardous materials within a Zone 4 after first securing a pern-dt and establishing a monitoring program- The program is implemented by the county Department of Environmental Resources. Other program components include inspection and monitoring to ensure compliance; engineering and site planning requirements such as spill containment facilities and removal of underground storage tanks (USTs); exemptions for emergency uses or public safety; a phased compliance schedule; and funding for relocating priority industries outside of Zone 1. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-17 General A1212licability to the Eastern Shore of Virginia The Palm Beach case study offers a valuable example to the Eastern Shore in effectively reducing risk of contan-dnation to water supplies through ranking water resource protection districts by sensitivity or vulnerability to contamination. Intermediate protection zones should be considered as in the "zoned approach" recommended in this study, where more stringent land use controls could be implemented. Ibis would allow for very stringent land use controls in close proximity to the wells and in the recharge area with less stringent controls required over the wellhead protection area. For More Information Mr. Allan Trefry, Manager, Department of Environmental Resources, Palm Beach County, Florida, (407) 3554011. COMPREHENSIVE MONITORING PROGRAMS State of Rhode Island: Salt-pond Watchers, Watershed Watch Water quality monitoring has typically been left to professionals, but a recent upsurge in citizen monitoring groups across the nation may soon change that approach. Citizen monitoring groups are active across the nation in carrying out the otherwise expensive routine water sample collection. Their efforts provide water resource scientists and mangers with a previously unavailable, extensive, continuous water quality record for a variety of water resources. Two citizen monitoring groups are currently collaborating with the University of Rhode Island (URI) in monitoring water quality in surface water bodies. The Rhode Island Salt Pond-Watchers is a group of over 100 senior citizens and other volunteers who regularly collect water quality samples for analysis from coastal ponds. Some analyses are carried out in the field with simple kits while others are performed at university, state, or federal laboratories. Samples are collected for nine months of the year, when the ponds are not frozen over. Pond Watchers receive training in water quality sampling methodology to ensure that the data collected can be used for a wide range of purposes including: � on-going formal monitoring; e early warning (to alert local or state authorities to a problem); � public health and shellfish monitoring. The Rhode Island Department of Environmental Management was initially skeptical about the value of the volunteer monitoring program, but has since reversed its official stand and has begun exploring options for collaboration. Using funds from an EPA grant, DEM is in the process of recruiting a statewide volunteer monitoring program coordinator. URI works with a similar group, named Watershed Watch, which focuses on freshwater ponds and lakes throughout the state. The Watch coordinates roughly 120 volunteers from land alliances, land trusts, town conservation committees, and watershed councils. After undergoing one indoor and one outdoor training session, the volunteers collect water quality measurements between May and October of each year. Volunteers measure lake transparency using a Secchi disk every week, collect samples for chlorophyll A concentration measurements, and take samples of water three times a Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-18 year for chemical analyses. The analyses include measurements of nitrogen, phosphorus, alkalinity, pH, magnesium, and calcium. Volunteers also collect on-site measurements of dissolved oxygen every two weeks from ponds deeper than five meters. The samples are forwarded to a university laboratory for analysis. A staff member and one graduate student are funded through the university's cooperative extension program. The baseline monitoring data are compiled and analyzed by the Watershed Watch university staff, who prepare an annual report. Watershed Watch also conducts shoreline surveys. Volunteers walk stretches of lake or river reach shores and note the presence of any dumped materials, odors from tributaries or other surface waters, bank erosion, etc. The information is entered into the program's Geographic Information System database for analysis. General Applicability to the Eastern Shore of Virginia Volunteer water quality monitoring programs could provide the Counties with regular, up-to-date water quality data for its priority ground water recharge protection areas. One possibility is to develop a collaboration with the University of Virginia which would offer trained chen-tical analysis and sampling program development expertise. For More Information Salt Pond Watchers Ms. Virginia Lee, Coastal Resources Center, University of Rhode Island, Narragansett, Rhode Island, (401) 792-6224. Watershed Watch Dr. Art Gold, Department of Natural Resources, University of Rhode Island, Narragansett, Rhode Island, (401) 792-2903. EPA Guidance Manual for States to Use Volunteer Monitoring. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 9-19 I I I I I CONCLUSIONS OF THE REPORT 1 10 I I I I I I I I I I I I I SEMON 10 - CONCLUSIONS OF THE REPORT The following serves as a summary of what is included in the body of the report, sections 1 through 9. SECTION I - Introduction This section contains an overview of the study and results, an executive summary, and a description of the purpose of the project. SECTION 2 - Water Resources on the Eastern Shore of Virginia Ground water quality and quantity are of the utmost importance on the Eastern Shore of Virginia because there are no other fresh water sources for drinking supplies. Ground water is derived from precipitation that hits the land surface of the two counties. The water that does not evaporate or run- off to small streams moves through the unsaturated zone of the soil and recharges the unconfined, shallow Columbia aquifer. Most water in the Columbia aquifer flows laterally from the center of the peninsula and discharges to the Atlantic Ocean and the Chesapeake Bay; a small portion of this ground water contributes to the base flow of small streams. A fraction of water in the Columbia aquifer continues migrating vertically down through a confining layer and reaches the Yorktown-Eastover aquifers located beneath the Columbia aquifer. The Columbia aquifer is primarily made of sands, with some clay and silt. The recharge rate from the Columbia (unconfined) to the Yorktown-Eastover (confined) aquifer is estimated to be 0.10 feet per year. Depending upon specific location, this figure may be higher or lower by a factor of two. The Yorktown- Eastover aquifer has three layers separated by confining units. The layers are referred to as the upper, middle, and lower Yorktown-Eastover aquifers. These permeable layers are composed of coarse, shelly sands and range in thickness from 10 to 120 feet. The confining units are between 10 and 70 feet thick. Since most of the ground water flows from the Columbia aquifer to the coasts, it is the water that is recharged from the center of the peninsula that reaches the Yorktown-Eastover aquifer. This area on the spine is later identified as an important area to protect. Total water use was calculated for the Eastern Shore of Virginia. Currently, agriculture is the biggest water user in the two counties. In Accomack County, agricultural water withdrawals range from 6.04 to 6.86 million gallons per day (MGD), and in Northampton the range is 1.94 to 5.17 MGD, largely depending on the rainfall that year. Farmers use a combination of ground water from wells and from dug ponds, and surface water from dammed creeks for irrigation, so it is difficult to detern-tine the impact of agriculture on specific aquifers. Public water supplies currently use 1.2 to 1.5 MGD, and are permitted to withdraw a total of 4.2 MGD. Industrial facilities are permitted for 10.7 MGD, but currently use water ranging from 3.1 to 3.4 MGD. These permitted facilities withdraw water from the Yorktown-Eastover aquifer. It is estimated that private homes use between 1.7 and 2.3 MGD, mostly from the Columbia aquifer, and non-community and non-transient, non-community public water supply facilities withdraw approximately 0.14 MGD. Chicken watering requires 0.234 MGD. SECTION 3 - Contamination Threats Several land uses pose a threat to the ground water in the Columbia aquifer. Because contaminants are discharged to the land or surface waters, the Columbia aquifer would be the first ground water source to become contarridnated. The ground water systems are interconnected, and contan-tination could, after time, reach the confined Yorktown-Eastover aquifer system. Potential sources of contamination were identified and quantified for the Eastern Shore of Virginia. They are as follows: Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 10-1 Public Sewage Systems - Only the three towns of Onancock, Cape Charles, and Tangier Island have public sewage, and these serve less than 4,000 people. On-site septic systems Septic systems are the most common form of household wastewater disposal in the area. It is estimated that 12,105 septic systems exist in Accomack County, and 5,008 are located in Northampton. Permitted discharges and mass drainfields - Facilities that discharge wastewater from a point source to surface waters must obtain a permit. There are 55 of these in the two counties. In addition there are 49 facilities that dispose of wastewater through mass drainfields, which are large septic systems. Aocultural fertilizers - Agricultural practices apply 5.5 million pounds of fertilizers per year. Pesticides - Many different pesticides are used on different crops against different pests. Quantities of pesticides used are not reported. Thus, there is no way of determining how much of a threat pesticides are to the ground water. Animal wastes - With a 1990 chicken population of 21 n-dllion birds, there were 21,000 tons of chicken manure produced. The manure is used to fertilize crop land. A natural mortality rate of 5% accounts for the disposal of 1.8 million pounds of dead birds per year. Underground storage tanks - There are 1,154 storage tanks on the Eastern Shore of Virginia. Of those, 684 (59%) are older than 15 years, and have a potential to leak. To date, 41 have been reported as leaking. Toxic chemicals - The Eastern Shore does not have many industrial facilities. There are several companies that use toxic chen-ticals, and these are listed in Tables 3-7 and 3-8. Solid waste - There are two public landfills in Accomack County, and one in Northampton County. The Northern Landfill in Accomack County is located on the spine recharge area (Zone 2 defined in section 5), which could be dangerous for the water supply should there be a leakage accident. The landfill is equipped with liners and runoff containers, and should not be a problem. Septage disposal - There are three lagoons in the two counties owned by private companies. They are unlined and are a threat to the ground water supply. One, in particular, is located on the spine recharge area. SECTION 4 - Existing Land Use Accomack and Northampton Counties have Comprehensive Land Use Plans and Zoning Ordinances that cover all land under jurisdiction of the County. The Comprehensive Plans represent development policy, and as such are not legally enforceable. Twelve incorporated towns have growth plans and zoning ordinances separate from the Counties. In Accomack County, current zoning for agricultural and residential land would allow for dense development to take place. In that case, it is possible that sufficient space required for a septic system and drainage field would be lacking. Accomack has a single residential district that can accommodate single family and.multi-fan-dly housing. There are no n-dnimum lot sizes for industries, which would also potentially create a high density situation. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 10-2 Northampton County agricultural districts allow for a larger minimum open space potential than in Accomack. Residential districts are more detailed in the number and type of housing units permitted and the conditions under which units are pern-dtted. Single fan-dly districts require larger lots than in Accomack County, but the primary building can take up as much as 66% of the lot (compared to 30% in Accomack), which leaves less space for septic systems. Both counties have a significant number of approved subdivisions which are as yet undeveloped. Many of the land uses are allowed by right, meaning that permits and reviews by each county are not required to determine whether the development will have an impact on ground water use or quality. The review process may need strengthening in cases where potentially harmful uses are proposed. The Chesapeake Bay Preservation Act is summarized in this section. The Act contains provisions for three general land categories: Resource Protection Areas (RPA), Resource Management Areas (RMA), and Intensely Developed Areas (IDA). Descriptions of each area is as follows: RPA -Defined as the land at or near the Bay which can protect water quality. If disturbed, water quality will be degraded. An RPA must have a buffer zone. Only redevelopment and water- dependent development can take place within an RPA. RMA - An RMA is the land which protects an RPA. Any development which is permitted by local zoning can take place within an RMA. IDA_7Significant development is allowed in, or pre-existed in an IDA. If an area has already been developed, an IDA may be located within an RPA or and RMA. All local governments are to have enacted local programs in accordance with the Chesapeake Bay Preservation Act by November, 1991. Locally prepared programs must meet general performance criteria, all of which relate to the ultimate use and condition of the ground water. Northampton County incorporated its program into a Draft Comprehensive Plan in 1990, and drafted an overlay zoning district. Accomack County has also drafted an overlay zoning district which is being assessed by the County Board of Supervisors. In both counties, the attention has been paid to the requirements for RPA's. There is less mention of RMA's, and no requirements are included for IDA's in either county's draft. SECTION 5 - Delineation of Ground Water Supply Management Areas Ground Water Supply Management Areas consist of three zones, and are summarized below. Zone 1: 200-foot radial distance around each well. This prevents contaminants from moving into the aquifers via a poorly constructed well or bad seal. Zone 1 also serves as protection against accidental spills near the wellhead. Zone 2: Hydrogeologic boundaries based on recharge areas. This area was determined based on a recharge rate of 9 inches per year to the Columbia Aquifer. Using permitted pumping rates, the land area required to balance that volume of withdrawal with the rate of recharge was calculated. Calculations determined that a width of 5,000 feet along the spine is the boundary of Zone 2. Zone 3: Hydrogeologic boundaries using contributing areas of flow. Zone 3 is based on ground water divides created by pumping patterns under permitted conditions. There are large drawdown areas on the peninsula because of a moderate to low transn-dssivity Ground Water Supply Protection and Managernent Plan for the Eastern Shore of Virginia 10-3 (water travel through the aquifer) within the Yorktown-Eastover Aquifers. Thus, Zone 3 covers virtually the entire peninsula, and is split into five different Wellhead Protection Areas (WPA). The five WPA's are summarized according to wells, discharges, landfills, lagoons, and acreage. WPA A includes the Chincoteague area; WPA B - Holly Farms (Tyson Foods); WPA C - Perdue; WPA D - Exmore; WPA E - Cape Charles. SECTION 6 - Water Budget/Balance Columbia Aquifer - The water budget approach indicates that there is 17 inches of water recharged to the Columbia Aquifer per year, assun-dng 50% runoff. With an area of 400 square miles of land, the recharge to the Columbia aquifer is 324 MGD. With so much water being recharged to the Columbia aquifer, there is little concern over the quantity of available water in this aquifer. Yorktown-Eastover Aguifer The rate of recharge to the Yorktown-Eastover aquifer system is slow, but the volume of water entering the confined system is large. Since recharge only occurs in the central portion of the peninsula, the spine, the area of recharge is only 200 square miles. With a recharge rate of 0.10 feet per year, approximately 11 MGD are being recharged to this confined aquifer. Permitted withdrawals for industrial and public water supply currently exceed that amount, and are at 15.6 MGD. This is independent of any withdrawals by agriculture or private facilities. Serious consideration should be taken to evaluate the quantities allowed to withdraw from the Yorktown-Eastover aquifer system. Salt Water Intrusion - Salt water can intrude laterally, vertically through the confining layers, or through upward vertical migration (upconing). If a well is pumped at too high a rate, salt water upconing will reach the well and contaminate the supply source. To prevent this from happening, it is best to maintain a stable pumping rate, rather than one of seasonal fluctuations. In general, water that has more than 250 mg/I of chloride tastes salty, and is unacceptable for drinking. In all likelihood, this is probably happening now at the Lower Yorktown-Eastover Aquifer, but since public and industrial wells are screened at three layers, the salt content is diluted before it reaches the faucet. SECTION 7 - Buildout/ Developable Lot Analysis The purpose of the buildout analysis is to evaluate the impacts of existing and potential land uses on ground water quality. For this, existing land uses within the spine recharge area (Zone 2) were assessed. According to current land use plans, potential development within the spine was then calculated. It was detern-dned that, if the area within Zone 2 was developed to its full potential with single farrdly houses, then the number of dwelling units in the spine alone would exceed the number currently existing in all of the two counties. SECTION 8 - Nitrogen Loading This section explains the potential dangers from nitrate-nitrogen contan-driation, including "blue baby syndrome" and possibly cancer. The current EPA standard limit for nitrate-nitrogen in water is 10 rrdlligrams per liter (mg/1). Sources of nitrate-nitrogen are sewage, fertilizers (agricultural and lawn), animal wastes, landfills, septage lagoons, pavement and roof runoff, industries, and precipitation. All inputs from these sources were calculated for the Eastern Shore of Virginia, and added together to predict the current average nitrate-nitrogen concentration in the ground water. This was found to be 2.0 mg/I in Accomack County and 1.9 mg/I in Northampton County. This falls well below the EPA Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 10-4 standard, but being an average for the area, this does not mean that there are no problem sites in either county. The largest contributors of nitrate-nitrogen are agriculture and septic systems. Existing water quality tests show low nitrate-nitrogen concentrations, with several isolated high readings. There are problems in some areas, especially in the Columbia (shallow) aquifer. Results from the buildout analysis were used to predict average nitrate-nitrogen concentrations under buildout conditions. These figures reflect the future concentrations if the land area in Zone 2 is built according to current land use plans. The HWH model predicts that WPA B would experience elevated nitrate-nitrogen concentrations of 13.5 mg/l. SECnON 9 - Case studies and Their Applicability To The Eastem Shore of Virginia A number of case studies are summarized in this section in order to illustrate different water resource protection strategies which may potentially benefit the Eastern Shore's efforts to protect its surface and ground waters. The subjects addressed in this section are agricultural influences, on-site waste disposal, surface water, hazardous materials, and monitoring programs. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 10-5 I I I I RECOMMENDAMNS I 11 1 I I I I I I I I I I I I I SECTION 11: RECOMMENDATIONS The Eastern Shore of Virginia is situated over a very valuable ground water resource that is a sole source of water supply to the inhabitants of Accomack and Northampton Counties. Ground water is the only significant supply source for public water withdrawals, private on-lot wells, industrial water use, and agricultural irrigation. The future land use plans for both counties are to maintain a low density pattern of development with growth occurring in the established villages and population centers. This study has identified the primary recharge area to the confined Yorktown-Eastover aquifer which is the principle source of water on the Eastern Shore. Protection of the excellent water quality in this aquifer will require the implementation of many actions designed to maintain the water quality, prevent against over use of the aquifer and provide for the future water needs to accommodate growth on the Eastern Shore of Virginia. The shallow Columbia aquifer has experienced water quality degradation in a number of areas. Since this aquifer is used primarily for on-site private water use, recommendations are presented to ensure that this planned use can continue. The Columbia aquifer also provides recharge to the confined Yorktown-Eastover aquifer system. Maintaining a high water quality in the Columbia ensures that land use threats to the confined aquifer will be minimized. Recharge estimates to both the Columbia and Yorktown-Eastover aquifers indicate that in combination there is sufficient water quantities to meet both the current and future water demands. In order to supply water for intended uses, proper water management is required in conjunction with protection of the water quality. These recommendations for ground water protection and management will also apply to Tangier Island. Land use conditions are similar on Tangier Island, however, water is withdrawn from a much deeper aquifer. Examples of most of the following recommendations that require local regulations are on file with the Accomack-Northampton Planning District Comn-tission. Recommendations for Water Quality and Quantity Protection #1: Water Conservation for Major Industrial Water Users The Ground Water Study Committee should pursue with major industrial users, fresh water conservation possibilities. These possibilities n-dght include the use of lower quality water for effluent dilution, and the reduction in wastewater flows from treatment plants. #2: Overlay Protection Zoning District. - Future Activities Based upon the Wellhead Protection Area Map prepared by HWH, and the delineation of wellhead protection areas and recharge areas to the Yorktown-Eastover aquifer, the Counties should adopt a zoning overlay ground water protection district. This action would apply only to future activities and not have any effect on existing facilities and development. The delineated protection zones should be dealt with in a progressively more relaxed fashion in terms of land use restrictions. Zone 1 is a 200-foot radius around pumping wells, Zone 2 is the spine recharge area to the Yorktown-Eastover aquifer, and Zone 3 is the delineated wellhead protection areas. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia - The area encompassing Zone 1 should have strict prohibitions excluding virtually all future potentially harmful activities within the 200-foot radius. The only activities that should be permitted within Zone 1 are passive recreation and maintenance of the wellhead itself. All pesticides, insecticides, herbicides, all storage of potentially dangerous material (salt, chen-dcals, petroleum products) should not be permitted within Zone 1. - Zone 2 should have land use restrictions commensurate with the delicate role it 12lays in recharging the Yorktown-Eastover aquifer. uch restrictions would be less onerous than those of Zone 1, but would include prohibiting the future siting of major polluting activities (landfills, septage lagoons, etc.) and requiring special permits based on performance standards for others (underground fuel storage tanks, toxic and hazardous materials, etc.) - Zone 3 should have the least restrictive land use Legulations, rel3ing heavily on 12ubli awareness to avoid contamination of the aquifers on the Eastern Shore. It should be remembered that this area also recharges the Yorktown-Eastover aquifer and all land use activities should be managed with protection of ground water quality in mind. The ground water resources are a sole source of supply to the residents of the Eastern Shore and as such should be protected and managed. #3: Restrict New Mass Drainfields in the Recharge Area ( Zone 2) The combined use of large septic systems by several businesses, homes, or industries provides a major point source of nitrogen loading and bacterial contamination to the Columbia Aquifer. This waste water disposal technique should, for the most part, not be allowed for future development in Zone 2. Overlay zoning can be employed to restrict mass drainfields within Zone 2. Any new mass drainfields installed within Zone 2 should prove that they can manage the facility and meet treatment levels allowed within that area. A performance standard could be established in the overlay zoning district for mass drainfields, or site plan reviews could incorporate the same requirements. #4: Review and Revise Counly Zoning and Subdivision Regulations Accomack and Northampton Counties should revise their current zoning and subdivision regulations to incorporate ground water quality and quantity protection. Most of the assessment of land use threats conducted during this study point to the need to control density, location, and the pattem of development. As zoning and subdivision regulations are revised, many of the suggested recommendations can be incorporated into the formal process of revisions. #5: HgQuire the Registration of Underground Storage Tanks Storing Volumes Less Than the State Rgq,uirements The Virginia Water Control Board currently regulates tanks which store more than 1,100 gallons of product. In order to adequately assess the threat from existing tanks, the counties should establish a registration program for all tanks storing less than 1,100 gallons. At this point, only registration of tanks is recommended. When ever possible, above-ground storage tanks should be used in place of underground tanks. #6: Inco=rate Ground water Protection Into Site Plan Review Both counties should revise their zoning ordinances to require that ground water protection be considered in all major site plan reviews. This will require developers of commercial and industrial sites to identify and mitigate potential negative impacts to ground water quality and quality from their development. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 11-2 #7. Private Well Ordinance Both counties should develop a health ordinance or revise subdivision regulations to require a minimum 300 foot separation distance in a downgradient ground-water flow direction for private wells finished in the Columbia aquifer from septic systems. Private on-site wells will continue to be a major water user on the Eastern Shore. Approximately 2 million gallons per day are withdrawn by private wells. In addition, where ever possible, new private wells should be finished in the Yorktown-Eastover aquifer to to eliminate the threat of nitrate contan-driation in the shallow aquifer. Water quality testing for nitrates for all new wells should be required prior to approval for use. #8: Encourage Agdcultural Nutrient Management Plans The Soil Conservation Service, County Extension Agents, and the Eastern Shore Soil and Water Conservation District should continue their program of assisting farmers in developing nutrient management plans. These plans should incorporate: soil nutrient testing; crop productivity recommendations; animal waste management; and fertilizer use record keeping. Especially important in Accomack County is the control of chicken waste products and disposal of dead chickens to minirrdze impacts on surface water and ground water resources. Government programs are in general developed to assure the general population adequate surplus food at minimum cost. As a result, farmers cannot pass along increased costs of production. As a result and in view of preliminary data concerning the submitted soil samples, it is recommended that cost-share assistance be considered, with time by the two counties and/or state, for soil testing through the Eastern Shore Soil and Water Conservation District. #9: Implement Chesal2eake Bay Program Both counties should implement the required provisions of the State of Virginia's Chesapeake Bay Act. The Act contains many provisions that will not only protect the quality of surface water drainage to the Chesapeake Bay, but also the ground water that ultimately discharges to the Bay. Specifically, the following provisions of the Act should be incorporated into local regulations: mandatory 5 year pump-out of septic systems; required reserve leach fields for septic systems; new development site plan review to include water quality protection; restrictions on impervious cover; stormwater quality management; and the protection of valuable wetlands. Recommendations for Water Quantity Management #1: Revise State Ground Water Act and Regulations A revision to the State Ground Water Act ( Chapter 3.4 of the State Water Control Board Statutes) which would allow re-authorizing of ground water withdrawals on the Eastern Shore is necessary to ensure that overuse of the confined aquifer does not result in saltwater intrusion, well interference, or create major drawdowns. The current permitted volumes may exceed the recharge rates to the Yorktown-Eastover aquifer as modelled by HWH. #2: Eastern Shore Water Management District Accomack and Northampton counties should explore the possibility of forn-ting a water supply district or water authority to centralize public and industrial water uses under one regulatory agency. There are currently several dozen active water withdrawal permits on the Eastern Shore. This promotes incomplete data bases, complicated administrative tracking and management and poor utilization of the ground water resource. The purpose of this recommendation is to encourage the consideration of a single water supply and management authority, especially to cover the geographic area of the spine Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 11-3 recharge zone. The Water Management District would be authorized to: plan for future water supply needs; obtain necessary state and federal permits; install and operate new public water supply systems that could service new areas; provide for the consolidation of the many systems that are currently in operation; and promote proper utilization of the ground water resource. As development continues on the Eastern Shore and more withdrawal permits are requested, the need for centralized management wfil become more apparent. #3: Water OuantijX Management -Existing and New Water SuMly Sources 0 New water supply sources that tap the Yorktown-Eastover aquifer should be located in the central pgrtion of the Eastern Shore pgninsula. This approach will minimize both lateral intrusion from salt water and vertical intrusion of salt water through confining layers. It will also simplify wellhead and aquifer protection since the position of the recharge area will not be skewed to one side or the other of the peninsula. : New water sul2pjy sources should be screened in the u12Rgr and middle Yorktown-Eastover. voiding the lower Yorktown-Eastover. Screening only the higher layers minimizes many of the problems of upconing of high chloride content water. 0 Wellfields rather than single wells to produce large volumes of water should be encouraged. A series of wells each pumping a moderate amount of water will create less upconing, less well interference and less lateral intrusion that one or two high volume wells. 0 New and existing water supply users should be encouraged to j2umj2 at moderate volumes on an extended basis and to use surface storage (tanks, lined ponds) rather than pumping hard for short intervals to meet peak demands. The continual pumping of moderate volumes will allow a smaller upcone to develop and to stabilize, eliminating much of the problem of salt and fresh water mixing that occurs with intermittent pumping. A progressively enlarged mixing zone between fresh and salt water will promote the intrusion of high chloride water into the fresh water zone. s The use of water supplies from the unconfined Columbia aquifer should be encouraged in situations where water -quality is less of a concern. The Columbia receives considerably more recharge than the Yorktown-Eastover aquifer, and while its water quality is sometimes marginal as a potable water supply, the quality is perfectly adequate for a number of industrial, agricultural and even domestic uses. High volume users of water that do not need water of drinking quality standards should be urged to use the Columbia as a source where adequate flows can be achieved. #4: [email protected] Repgrting of Large Agricultural Water Withdrawals Agricultural water withdrawals have been identified as the largest single source of water use on the Eastern Shore. Yet very little is known about how this water is used and from which aquifer it is obtained. State Water Control Board Regulations currently require that irrigators which withdraw more than 1 million gallons/day on the average for any month report this use to the VAWCB. The Ground Water Committee should develop public educational materials to inform irrigators of the need to collect accurate information on their water use. #5: Consider Permitting of Large Agricultural Water Withdrawals If after review of the reporting of large agricultural water withdrawals it becomes apparent that these withdrawals are significant contributors to the total withdrawal from the Yorktown-Eastover aquifer, the Virginia State Water Control Board should be encouraged to regulate the amounts and locations of Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 11-4 existing and future agricultural withdrawals. This will provide for better management and control of withdrawals from the aquifer. #6: Protect QWn Space in the Spine Recharge Area Local governments on the Eastern Shore should seek to acquire public open space in the Zone 2 Recharge Area. This can be accomplished with the assistance of public conservation groups such as The Nature Conservancy, which has already acquired most of the coastal marsh areas of the Eastern Shore. Public land ownership will ensure the protection of water quality and allow for the control and development of prime water supply development sites. General Recommendations #1: Implement a Land Use/Water Quality Data Base The A-NPDC should consider the establishment of a centralized water quality data base for all water use on the Eastern Shore. Experience from the study identifies the need for centralized data to continue the planning and management of the the ground water resource. Data collection and synthesis was very time consuming and could greatly reduce future planning and analysis costs with the development of a central repository of water quality information. In addition, land use information could also be centralized and managed by the A-NPDC to allow the agency to assist the counties in implementing land use controls for water resource protection. #2: Public Education on Ground water The Eastern Shore of Virginia Ground Water Study Committee should continue to develop materials and provide information to the public on the importance of the ground water resource on the Eastern Shore. Additional publications, meetings, forums, etc. should be planned to encourage support for ground water protection and management. Continued support for research conducted by the US Geological Survey should be a primary activity for the Cornmittee. This research will form the basis for many future decisions regarding ground water management. Continued Research and Investigation #1: Investigate the Nature of Recharg!2 to the Yorktown-Eastover System The rate, volume, timing and distribution of recharge from the unconfined Columbia aquifer to the Yorktown-Eastover aquifer remains a focal point to the water supply problems on the Eastern Shore. If the rate of recharge is as low or lower than has been modelled analytically in this study, and if the area over which recharge occurs is smaller than the 200 to 300 square miles used, the issue of water quantity in the Yorktown-Eastover aquifer becomes even more important than has been argued here. Because this is a key issue, additional work should be considered to attempt to better quantify the recharge component of the hydrologic cycle. It may be possible, for example, to employ the USGS finite difference model designed to model salt water intrusion, currently in review (Richardson, in press), using that database as a means to better quantify the rate, volume and areal distribution of recharge to the confined system. Results from the Richardson report should be incorporated into the Protection and Management Plan when this report is available. #2: Research Dilute Salt Water Issues Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 11-5 Salt water movement into both the Columbia and Yorktown-Eastover aquifers is a very important and real threat on the Eastern Shore. Additional study is needed to quantify the limits of salt water in the 250 milligrams per liter range. This information is necessary to determine the lin-dtations that may need to be set on individual water withdrawals. #3: Investigate the Character of Pleistocene Paleochannels on the Eastern Shore A major focus of continued research should focus on the paleochannels that cross the Eastern Shore. These could prove to be major sources of supply to the two counties, but their use would have to be coupled with a solid understanding of the geometry and flow patterns involved. It is likely that the deep central portions of the channels possess sands and gravels from the depositing stream that formed the channel, deposits that probably would have good permeability and would make excellent aquifers. However, development of such materials would have to be done carefully to avoid both upconing and vertical intrusion of salt water. Since the permeable deposits would be at the bottom of the channels, they would be closest to underlying salt water and subject to upconing problems that could ruin an otherwise good well. Since the channels are documented as connecting to the mainland, passing beneath Chesapeake Bay (Colman and others, 1990), a substantial portion of the channels lie beneath salt water. Excessive pumping of a well located in a paleochannel on the Eastern Shore peninsula could result in contamination from salt water intruding vertically in response to the gradients created by pumping- #4: Evaluate Pesticides Use on the Eastern Shore The impact of pesticide use on ground water quality on the Eastern Shore should be studied. Currently, information is not available to accurately assess this potential source of contarridnation. The VA Department of Agriculture and Consumer Services, Office of Pesticide Management should be contacted to provide assistance in this effort. Since agriculture is planned as the predon-dnant land use in the future, this effort should be a priority for future investigations. #5: Agricultural Nutrient Management Research Additional research should be conducted on the specific nature of agricultural nutrient use and impacts on the water resources of the Eastern Shore. This study utilized general information regarding nitrogen application rates, leaching potential, chicken litter disposal and use, and dead chicken disposal. More specific information is necessary on: actual nitrogen application rates and amounts used by crop types; nitrogen leaching rates by soil types found on the Shore: an accurate assessment of chicken litter use and disposal of dead chickens; quantification of the success of nutrient management plans in reducing nitrogen use and loss; fate and transport of nitrogen in the ground water system (Columbia and Yorktown-Eastover). #6: Revise Nitrogen Modelling Nitrogen is a very good indicator of overall ground water quality. The nitrogen model used in this study to assess land use impacts should be revised as more detailed information becomes available. Virginia Tech is currently conducting a study of nitrogen contamination in the ground water of the Eastern Shore. This new data can be used to update and verify the results of the model. The model is designed to allow for easy revisions and scenario testing. The model can be used in planning new development and in the assessment of zoning changes. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia 11-6 I I I I I WATER QUALITY I APPENDIX A I I I I I I I I I I I I I Regulated Contaminants The following is a list of drinking water contaminants for which the U.S. Environmental Protection Agency is setting health-based standards (Maximum Contaminant Level Goals, or MCLGs) and enforceable standards (Maximum Contaminant Levels, or MCLs) For some contaminants, there is also a Secondary Maximum Contaminant Level (SMCL), a level set to prevent taste or odor problems. Unless otherwise indicated, the levels presented are milligrams per liter (mg/1). For some contaminants, the MCL is a prescribed treatment. See "Setting the standards for safe drinking water" and contaminant descriptions for more information. Contaminant MCLG MCL SMCL Interim acrylamide 0 .005% dosed at 1 mg/l adipates2 O.S O.S alachlor 0 0.002 aldicarbl 0.01 0.01 aldicarb sulfonel 0.04 0.04 aldicarb sulfoxidel 0.01 0.01 alpha particle acitity (gross7) 15 pCi/l antimony, 0.003 0.01 or 0.005 arsenic4 0.05 asbestos 7 million fibers/liter atrazine 0.003 0.003 bariuml 5 5 1 benzene 0 0.005 beryllium2 0 0.001 4 mrem/yr beta particle and photon radioactivityr- cadmium 0.005 0.005 0.01 carbofuran 0.04 0.04 carbon tetrachloride 0 0.005 chlordane 0 0.002 chlorobenzenel 0.1 0.1 0.1 chromium 0.1 0.1 0.05 copperl 1.3 1.3 cyanide2 0.2 0.2 dalapon2 0.2 0.2 dibromochloropTopane (DBCP) 0 0.0002 o-dichlorobenzene 0.6 0.6 0.01 p-dichlorobenzene 0.075 0.075 0.005 1,2-dichloroethane 0 0.005 1,1-dichloroethylene 0.007 0.007 cis-1,2-dichloroethylene 0.07 0.07 trans-1,2-dichlOToethylene 0.1 0.1 2,4-dichlorophenoxyacetic acid (2,4-D) -0.07 0.07 0.1 1,2-dichloropropanel 0 0.005 dinoseb7 0.007 0.007 dioxin (2,3,7,8-TCDD)2 0 0.00000005 dig t2 0.02 0.02 endothaI12 0.1 0.1 endrin2 0.002 0.002 0.0002 epichlorohydrin 0 .01 % dosed at 20 mg /I ethylbenzene 0.7 0.7 0.03 proposed May 1989; may be finalized December 1990 2proposed July 1990 3to be proposed February 1991 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia A-1 Contaminant MCLG MCL SMCL Interim ethylene dibromide 0 0.00005 fluoride 4 4 2 Giardia lamblia 0 treatment glyphosate2 0.7 0.7 heptachlor 0 0.0004 heptachlor epoxide 0 0.0002 hexachlorobenzene2 0 0.001 hexachlorocyclopentadiene2 0.05 0.05 0.008 leadl 0 0.005 0.05 Legionella 0 treatment lindane 0.0002 0.0002 0.004 mercury 0.002 0.002 0.002 methoxychlor 0.04 0.04 0.1 methylene chloride2 0 0.005 nickel2 0.1 0.1 nitrate (as N) 10 10 10 nitrite (as N) 1 1 pentachlorophenoll 0.2 0.2 0.03 phthalales2 0 0.004 picloram2 0.5 0.5 polychlorinated biphenyls (PCBs) 0 0.0005 polycyclic aromatic hydrocarbons (PAhs)2 0 0.0002 radium 226 and 2283 5 pCi/l radon3 selenium 0.05 0.05 0.01 simazinel 0.001 0.001 standard plate count treatment styrene 0.1 0.1 0.01 sulfate2 400 or 500 400 or 500 tetrachlOToethylenel 0 0.005 thallium2 0.0005 0.002 or 0.001 toluene 1 1 0.04 total coliforms 0 treatment toxaphene 0 0.003 0.005 trichlorobenzene2 0.009 0.009 1,1,1-trichloroethane 0.2 0.2 1,1,2-trichloroethane2 0.003 0.005 trichloroethylene 0 0.005 2,4,5-trichlorophenoxypropionic acid (Z4,5-TP) 0.05 0.05 0.01 turbidity treatment uranium3 vinyl chloride 0 0.002 viruses 0 treatment 7daJ 0.2 0.2 xylenes (total) 10 10 0.02 4to be dealt with separately 5longer than 10 gm Source: What Do The Standards Mean?: A Citizens' Guide to Drinking Water Contaminants, VA Tech. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia A-2 I I I I I POPULATION APPENDIX B I I I I I I I I I I I I I I Table B-1: 1990 U.S. Census Population Counts Accomack-Northampton Planning District people/units _Lgcality Population Counts Housing Units Density Accomack County 31,703 15,840 2.00 Accomack Town 466 205 2.27 Belle haven Town 526 245 2.15 Bloxorn Town 357 175 2.04 Chincoteague Town 3,572 3,167 1.13 Hallwood Town 228 115 1.98 Keller Town 235 107 2.20 Melfa Town 428 191 2.24 Onancock Town 1,434 705 2.03 Onley Town 532 276 1.93 Painter Town 259 113 2.29 Parksley Town 779 393 1.98 Saxis Town 367 192 1.91 Tangier Town 659 277 2.38 Wachapreague Town 291 223 1.30 Outside of incorporated towns 21,570 9,456 2.28 Northampton County 13,061 6,183 2.11 Cape Charles Town 1,398 689 2.03 Cheriton Town 515 246 2.09 Eastville Town 185 94 1.97 Exmore Town 1,115 528 2.11 Nassawadox Town 564 227 2.48 Outside of incorporated towns 9,284 4,399 2.11 A-NPD TOTAL 44,764 22,023 2.03 Table B-2: Historical and Projected Population Figures Year 1950 1960 1970 1980 1985 1990 1995 2000 Population Accomack County 33,832 30,635 29,004 31,268 31,200 33,000 33,300 34,000 31,130- 31,990' Northampton County 14,442 14,625 14,700 15,000 15,000 15,300 A-NPD 43,446 45,893 46,500 48,000 48,300 49,300 Sources: VSWCB Eastern Shore Water Supply Plan, 1988; Accomack County Comprehensive Plan, 1989 (*- A-N PDC linear TMI model). Both used the following sources: US Bureau of the Census, Virginia Department of Health, Tayloe-Murphy Institute. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia B-1 I I I I LAWS AND REGULATIONS APPLICABLE TO STUDY I APPENDIX C I I I I I I I I I I I I I I LAWS AND REGULATIONS APPLICABLE TO THE STUDY Virginia State Water Control Board Statutes. July 1. 1990 Chapter 3.1 - State Water Control Law Article 4. Regulation of Sewage Dischargr.1 All sewerage and sewage treatment operations are under joint supervision of the State Department of Health and the Board. If a proposed facility will serve more than 400 people and if it has potential for or actual discharge to state waters, owners shall file an application to the Board and the State Department of Health for a certificate before any erection, construction, operation, or expansion can occur. In 1977, owners and operators of sewerage systems and sewerage and industrial waste treatment works conducted a survey in order to determine the physical, chemical, and biological properties of discharge. Vir&ia State Water Control Board Statutes, July 1. 1990 Chapter 3.4 - The Groundwater Act of 1973 The basic premise behind this act is that the right of water control belongs to the public, but in order to ensure public welfare, safety, and health, provisions must be made for control of ground water. The Board and the State Department of Health administers and enforces the provisions of this chapter. Special care is taken to protect Groundwater Management Areas (GMA). The Board will initiate a study if it is believed that in a certain area ground water levels are declining, two or more wells are interfering, the ground water supply is or will be overdrawn, or the ground water is or is expected to be polluted. Should an area be deemed a GMA, one must obtain a permit in order to withdraw ground water from such area. No certificate is needed to withdraw from an area that is not declared a GMA, nor for those withdrawing less than 300,000 gallons/month or for agricultural or livestock purposes. The Board may establish regulations which will require only agricultural withdrawal greater than 300,000 gallons/month to be reported. VR 680-14-01 - State Water Control Board Regulations - Pollution Abatement Permit Regulation This regulation sets guidelines for pretreatment programs, and identifies procedures and requirements to be followed in connection with Virginia Pollutant Discharge Elin-tination System (VPDES) and Virginia Pollution Abatement (VPA) permits issued by the Board pursuant to the Clean Water Act or the State Water Control Law. Pern-dts are required for discharge of anything that may alter state waters. Point sources are authorized by a VPDES permit, non-point by a VPA permit. Any spills, unplanned bypasses, or non-compliance which may endanger state waters must be reported by telephone within 24 hours. Animal feeding operations are subject to the VPA permit program if they are considered concentrated (100,000 laying hens or broilers) or intensified (30,000 hens, broilers). Under this regulation, animal feeding operations (animals are stationed or fed on premises for at least 45 days per year) shall maintain no point source discharge of pollutants to state waters except in the case of a 25 year, 24 hour storm event. VR 680-14-03 - State Water Control Board Regulations. Pollution Abatement Toxics Management Regulation The purpose of this regulation is to control the levels of toxic pollutants in surface waters discharged from all sources holding VPDES or NPDES permits. It provides standards and procedures to minimize or prevent any toxic discharge in levels dangerous to human health or the environment. Whenever VPDES permits are issued or modified, the Board will determine whether or not there is a need for toxics management. Toxics monitoring must be done if the discharge has actual or potential toxicity, if the permitted works falls into the Industry Class, if the industrial wastewater flow is greater than 500,000 gallons/day, if a Publicly Owned Treatment Works Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia C-1 (POTW) discharges greater than 1 million gallons per day, or if a POTW undergoes a pretreatment program. State Water Control Board Regulations - Pollution Abatement Regulation No. 8. Sewerage Regulations These regulations were adopted jointly by the State Water Control Board and the State Board of Health. They were set up in order to ensure that the design, construction, and operation of sewage treatment works and sewerage systems are consistent with public health and water quality objectives of the Commonwealth of Virginia. The regulations assist owners in preparation of an application, plans, or data and lay the rules by which the Board will review and make decisions in regards to the specifications and applications. State Water Control Board Regulations - Water Supply Data VR 680-15-01. Water Withdrawal RgRgifing Under this regulation, water withdrawal information will be submitted to the Board for the purpose of formulating and preparing plans and programs for the management of water resources in the Commonwealth of Virginia. The data will also be available to local governments and local interests to assist them in their own water supply planning. The regulation applies to every user withdrawing ground water or surface water whose daily average withdrawal during any month exceeds 10,000 gallons/day. It also applies to every user withdrawing ground or surface water for the purpose of irrigating crops whose withdrawal exceeds 1 million gallons in any single month. Industrial VPDES pem-dttees must report their source and location annually. Every nonexempt user other than crop irrigators shall have installed and shall operate a gaging device . Crop irrigators shall comply with measuring provisions by January 31, 1991. Every nonexempt user shall file with the board a reporting form every January 31 of each year.. The information reported includes source(s) and locations of withdrawal, cumulative volume of water withdrawn each month, method of withdrawal measurement, and maximum day withdrawal. Crop irrigators shall comply with reporting provisions by January 31, 1992 State Water Control Board Regulations - Groundwater Rules and Standards for Water Wells So that equitable development and utilization of ground water is achieved in Virginia, these rules and standards set forth the authority for controlling ground water. Essentially, these rules and standards set provisions to prevent wells from becoming a source or channel for the entry of pollutants or contaminants. Under the jurisdiction of this regulation are: registration statements, construction and maintenance of wells, observational and abandoned wells, data and records, and general requirements. Methods for testing well yield are described. VR 680-21-M - State Water Control Board Regulations - Water Quality Standards The State Water Control Law, Section 62.1-44.15(3), mandates the protection of existing high quality state waters and also provides for the restoration of all other state waters to a condition of quality which will allow all public uses: water-based recreation, public water supply, and growth of balanced populations of fish and wildlife. In this regulation, water quality requirements for surface waters and ground water are described and listed in tables in numeric limits and general terms for specific physical, chemical, biological, and radiological characteristics of water. These limits set the standards that must be met by all discharge applicants. Municipal and industrial discharge mixing zones are viewed separately, and must not threaten recreation and wildlife use. In addition, special standards for shellfish waters are set for the median fecal coliform value. Extra precautions must be made in surface waters so that eating shellfish is not hazardous. The Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia C-2 Board will convene a public hearing to talk about any proposal that would result in the Department of Health condenu-dng shellfish beds. Acknowledging that ground water quality varies in different areas, the Board has divided the state into four physiographic provinces by which they establish different criteria. The Eastern Shore is in the Coastal Plain region. In order to prevent the entry of pollutants into the ground water in any aquifer, a soil zone or alternate protective measure or device is established to preserve and protect the ground water. State Board of Health - Waterworks Reeulations' These regulations establish that the State Board of Health has the duty to ensure that all water supplies destined for human consumption be pure water. All wells must be constructed by registered Virginia contractors, and wells sampling done by approved laboratories. Frequent sanitary surveys must be made by the owner to locate and identify health hazards. Once a hazard is identified, the rate it is removed will be determined by the Division of Water Supply Engineering. Sampling frequencies are listed in this regulation, and are based upon the number of people served and whether or not the water supply is community, non-transient community, or non- community. Categories for those to be sampled are coliform bacteria, inorganics, organics (pesticides, VOC's, UC's, THM's), radiological, and physical characteristics like turbidity. Nitrates must be sampled once every three years for community and non-transient community, and every five years for a non-community water works. When a new water supply system is considered, the capacity of the source must be adequate to sustain anticipated growth. Construction and location requirements for drilled wells are the following: 1) There shall be a distance of at least 50 ft. from the well to the property lines of the well lot. 2) If an access road is needed, it will be counted as part of the well lot. 3) There must be a horizontal distance of 50 ft. from the well to any septic tank, barn yard, privy, pipe carrying sewage, petroleum or chemical storage tank, or pipe line. If plastic well casing is used, the distance is 100 ft. A water well completion report must be submitted. The report will include yield and drawdown test data for a n-dnimum period of 48 hours. Chapter 14.1 - ViMinia Pesticide Control Act. 1989 Session This Act establishes a Pesticide Control Board which adopts rules concerning pesticides and the application of them. The Board also serves the public by informing them as to the desirability and availability of non-chen-tical and less toxic alternatives to chemical pesticides. It promotes the use of Integrated Pest Management techniques and the safe and proper use of pest control products. The Board has the power to restrict or prohibit the use of any particular pesticide. All pesticides must be registered, and all applicators must have a license to do so (researchers excluded). The Board acts as enforcer of rules, and can levee fines as a result of violations. Pesticide accidents must be reported. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia C-3 YR 115-04-03 - Vkginia DeRartment of A&dculture and Consumer Services Rules and Regulations for Enforcement of the Vireinia Pe ticide Law These regulations list guidelines for the application, storage, disposal, and sale of pesticides. The concept of "pest" is defined, and the types of pest control are placed into categories. Rules are established for toxicity codes and for labeling pesticides. VR 115-04-21 - Public ParticiRation Guidelines, Pesticide Control Board Del2artment of Agriculture and Consumer Services. Pesticide Control Board These guidelines establish methods for identification and notification of those persons or groups interested in the development of regulations of the Pesticide Control Board. Mailing lists, public meetings, committees, and the process of making a regulation are all described here. VR 115-04-22 - ViMinia DeRarbnent of Agriculture and Consumer Services Regglations, Governing Licensing of Pesticide Business ORerating Under Authority of ViMinia Pesticide Control Act SeRtem These regulations introduce procedures and requirements for obtaining a pesticide business license. A license is required for anyone who sells, stores, mixes, applies or recommends pesticides, and this includes pest management consultants. Businesses must demonstrate evidence of financial responsibility and keep records according to the rules. Failure to be properly licensed, financially responsible, or to submit records when asked can result in revocation, suspension, or denial of a business license by the Board. VR 115-04-23 - Regulations Governing Pesticide ARRlicator Certification Under Authorily o Vir&ia Pesticide Control Act (Pro2osed. as of 2/91) Several sections of VR 115-04-03 are superseded by these proposed regulations. VR 115-04-23 sets standards of certification for persons specified by the statute to require certification, and standards of financial responsibility for commercial applicators. Those who must meet the requirements are individuals, employees, or representatives of government agencies who use or supervise the use of pesticides in the performance of their official duties. All must pass a general exan-driation, and then be tested in a specific category of pesticide application. The general tests assure that all applicators are able to handle accidents, know labels, application techniques, laws and regulations, can identify pests, and are aware of environmental affects of pesticides. Commercial applicators not for hire are required to keep records for two years, while commercial applicators must maintain records of each restricted-use pesticide. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia C-4 I I I I I EASTERN SHORE OF VIRGINIA GROUND WATER STUDY COMMITTEE I APPENDIX D I I I I I I I I I I I I I EASTERN SHORE OF VIRGINIA GROUND WATER STUDY COMMITTEE Membership: The Committee consists of the following representatives from Accomack and Northampton Counties: 2 members from each Board of Supervisors 1 citizen appointee from each Board of Supervisors the County Administrator from each county the Executive Director of the Accomack-Northampton Planning District Commission Members: Honorable C.D. Fleming, Jr. H. Mapp Walker Accomack County Citizen Member, Northampton County P.O. Box 101 Bayford Road New Church, VA 23415 Franktown, VA 23354 (804) 824-3724 (804) 442-2665 Honorable Donald L. Hart, Jr Arthur K. Fisher Accomack County Accomack County Administrator P.O. Box 100 P.O. Box 388 Keller, VA 23401 Accomac, VA 23301 (804) 442-6818 (w); (804) 787-7166 (h) (804) 787-5700 Honorable P.C. Kellam, Jr. John M. Richardson Northampton County Northampton County Adn-dnistrator RFD P.O. Box 66 Exmore, VA 23350 Eastville, VA 23347 (804) 678-5659 (w); (804) 442-7852 (804) 678-5148 Honorable Parkes A. Downing Paul F. Berge, AICP Northampton County Executive Director, A-N PDC Franktown, VA 23354 P.O. Box 417 (804) 442-6810 Accomac, VA 23301 J. Holland Scott (804) 787-2936 Citizen Member, Accomack County One Merry Lane Onancock, VA n417 (804) 787-4382 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia D-1 Technical Assistance: Mr. Gary Anderson, Chief Ms. Virginia Newton U.S. Geological Survey Virginia State Water Control Board 3600 W. Broad Street, Room 606 287 Pembroke Office Park Richmond, VA 23230 Suite 310, Pembroke No. 2 Virginia Beach, VA 23462 Mr. Jim Belote Extension Agent, Agriculture Mr. Gary Oliveri County of Accomack Accomack County Planner P.O. Box 60 P.O. Box 388 Accomack, VA 23301 Accornack, VA 23301 Mr. Mark Bushing Ms. Donna Richardson Virginia State Water Control Board U.S. Geological Survey 287 Pembroke Office Park 3600 W. Broad Street, Room 606 Suite 310, Pembroke No. 2 Richmond, VA 23230 Mr. Mike Focazio Mr. John Selby U.S. Geological Survey USDA, Resource Conservation 3600 W. Broad Street, Room 606 & Development Richmond, VA 23230 P.O. Box 127 Accomack, VA 23301 Ms. Pixie Hamilton Mr. Gary Spieran U.S. Geological Survey U.S. Geological Survey 3600 W. Broad Street, Room 606 3600 W. Broad Street, Room 606 Richmond, VA 23230 Richmond, VA 23230 Mr. John L. Humphrey Mr. Terry Wagner Planning and Zoning Virginia State Water Control Board Northampton County Adn-dnistration 2111 N. Hamilton Street P.O. Box 66 Richmond, VA 23230 Mr. Robert F. Jackson Mr. J. Rodney Lewis Virginia State Water Control Board District Conservationist 287 Pembroke Office Park Soil Conservation Service Suite 310, Pembroke No. 2 Accomac, VA 23301 Virginia Beach, VA 23462 Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia D-2 I I I I I HYDROGEOLOGIC CALCULATIONS APPENDIX E I I I I I I I I I I I I I I Table E-I: Water Balance for the Eastern Shore of Virginia Recharge to the Columbia (Unconfined) Aquifer (After Dunne and Leopold, 1978) Potential ET Average Average (from Precipitation Accumulated Change Soil Soil Available Assume -74 Monthly Monthly Thornthwaite minus Potential Soil in soil Actual Moisture Moisture for runoff or 50% Detention Detention 1z Precipitation Precipitation method) Potential ET Water Loss Moisture moisture Er Deficit Surplus recharge Runoff (recharge) (recharge) (inches) (mm) (mm) (mm) (mm) (m m) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (inches) January 3.41 86.6 6 81 200 0 6 0 81 136 68 68 2.7 February 331 84.1 8 76 200 0 8 0 76 144 72 72 2.8 March 4.13 104.9 24 81 2DO 0 24 0 81 153 77 77 3.0 April 2.92 74.2 46 28 200 0 46 0 28 105 52 52 2.1 May 3.47 88.1 77 11 200 0 77 0 11 63 32 32 1.2 June 3.51 89.2 103.5 -14 -14 190 -10 99.2 4.4 0 32 16 16 0.6 July 4.10 104.1 118.7 -15 -29 185 -5 109.1 9.6 0 16 8 8 0.3 August 4.28 108.7 111 -2 -31 183 -2 110.7 03 0 8 4 4 0.2 September 3.41 86.6 84 2 -29 185 2 84 0 0.2 0.2 0.1 0.1 0.005 October 3.57 90.7 52 39 200 15 52 0 39 39.1 20 20 0.8 November 2.96 75.2 25 50 200 0 25 0 50 70 35 35 1.4 December 3.37 85.6 10 75 200 0 10 0 75 110 55 55 2.2 TOTAL 42.44 1078 665 413 2343 651 143 442 976 438 438 Note. Assumes soils with 200 mm (8 inches) of available water capacity E-i Table E-2: Thorthwaite Method for Evapotranspiration (ET) Calculation 3 LOCATION: Eastern Shore, Virginia CLIMATOLOGICAL DATA FROM: Painter, Virginia YEARS OF RECORD: 6 (1985-1990) Mean Monthly Positive Air Uncorrected Potential Potential Air Temperature Monthly EIr Latitude Correction Factor EIr EIr Temperature Values Heat Index (cm/month) Latitude 400 N (cm/month) (in/month) January 3.94 3.94 0.70 0.76 January 0.80 0.61 0.24 February 4.28 4.28 0.79 0.85 February 0.89 0.76 0.30 March 9.11 9.11 2.46 2.40 March 0.99 2.38 0.94 OQ April 13.72 13.72 4.55 4.21 April 1.10 4.63 1.82 May 18.67 18.67 7.21 6.41 May 1.20 7.69 3.03 June 22.50 22.50 9.55 8.28 June 1.25 10.35 4.08 July 25.17 25.17- 11.29 9.65 July 1.23 11.87 4.68 August 25.17 25.17 11.29 9.65 August 1.15 11.10 4.37 September 22.17 22.17 9.33 8.11 September 1.04 8.44 3.32 October 16.83 16.83 6.18 5.56 October 0.93 5.18 2.04 November 10.72 10.72 3.14 3.00 November 0.83 2.49 0.98 December 5.89 5.89 1.28 1.32 December 0.78 1.03 0.41 ANNUAL HEAT INDEX, I = 67.77 "a" factor = 1.37 Total Potential ET 67 26 cm/year in/year E-2 Table E-3: Water Balance for the Eastern Shore of Virginia Recharge to the Yorktown-Eastover Aquifer Derived Equation: Recharge Rate Calculations: Recharge (R) = [ 8 T h) - [LA2 - 4 XA2] Transmissivity M in ft2/day Head N in feet (at ground water divide) x = 0 in all cases (at ground water divide) Width of peninsula Q in feet Recharge values (below) in feet per year For peninsula width of 4 miles T = T T = T T T 500 1000 2000 3000 4000 5000 h = 15 0.05 0.10 0.20 0.29 0.39 0.49 h = 18 0.06 0.12 0.24 0.35 0.47 0.59 h = 20 0.07 0.13 0.26 0.39 0.52 0.65 h = 22 0.07 0.14 0.29 0.43 0.58 0.72 h = 24 0.08 0.16 0.31 0.47 0.63 0.79 h = 26 0.09 0.17 0.34 0.51 0.68 0.85 Average R 0.07 0.14 0.27 0.41 0.55 0.68- Overall Average R =1 0.29 feet per year For peninsula width of 6 miles T = T T = T T T Soo 1000 2000 3000 4000 5000 h = 15 0.02 0.04 0.09 0.13 0.17 0.22 h = IS 0.03 0.05 0.10 0.16 0.21 0.26 h = 20 0.03 0.06 0.12 0.17 0.23 0.29 h = 22 0.03 0.06 0.13 0.19 0.26 0.32 h = 24 0.03 0.07 0.14 0.21 0.28 0.35 h = 26 0.04 0.08 0.15 0.23 0.30 0.38 Average R 0.03 0.06 0.12 0.18 0.24 0.30 Overall Average R = 0.13 feet per year [email protected] For peninsula width of 8 miles T = T T = T T T 500 1000 2000 3000 4000 5000 h = 15 0.01 0.02 0.05 0.07 0.10 0.12 h = 18 0.01 0.03 0.06 0.09 0.12 0.15 h = 20 0.02 0.03 0.07 0.10 0.13 0.16 h = 22 0.02 0.04 0.07 0.11 0.14 0.18 h = 24 0.02 0.04 0.08 0.12 0.16 0.20 h = 26 0.02 0.04 0.09 0.13 0.17 0.21 .111verageR 0.02 0.03 0.07 0.10 0.14 0.17- Overall Average R =1 0.07 feet per year Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia E-3 Table E-4: Recharge Calculations for the Yorktown-Eastover Aquifer Volumetric Recharge Calculations (All figures in million gallons per day) Area for Area for Area for Area for Area for Recharge Recharge Recharge Recharge Recharge Recharge Rate (mi2) (mi2) (mi2) (mi2) (mi2) (feetlyear) 100 L50 200 300 400 0.05 3 4 6 9 11 0.10 6 9 11 17 23 0.20 11 17 23 34 46 0.30 17 26 34 51 69 0.40 23 34 46 69 91 0.50 29 43 57 86 114 0.60 34 51 69 103 137 1 Comparison of Water Usage on the Eastern Shore with Recharge Volumes Area of confining layer receiving recharge = 200 square miles Variable recharge rates (All figures in million gallons per day) Year Year Year Year Year Year Permitted IM 1986 1987 1988 1989 1990 Amount Public Sources: 1.243 1.264 1.259 1.241 1.415 1.114 4.462 Industrial Sources: 3.412 3.052 3.157 3.064 3.433 3.430 11.143 Total Withdrawals: 4.655 4.316 4.417 4.306 4.948 4.544 15.604 Recharge at 0.05 ft/yr 6 6 6 6 6 6 6 Excess or Deficit. 1.1 1.4 1.3 1.4 0.9 1.2 -9.9 at 0.10 ft/yr 11 11 11 11 11 11 11 Excess or Deficit: 6.8 7.1 7.0 7.1 6.6 6.9 -4.2 at 0.20 ft/yr 23 23 23 23 23 23 23 Excess or Deficit: 18.2 18.5 18.4 18.5 18.0 18.3 7.2 at 0.30 ftlyr 34 34 34 34 34 34 34 Excess or Deficit: 29.6 30.0 29.9 30.0 29.4 29.7 18.7 at 0.40 ftlyr 46 46 46 46 46 46 46 Excess or Deficit: 41.1 41.4 41.3 41.4 40.9 41.2 30.1 at 0.50 ftlyr 57 57 57 57 57 57 57 Excess or Deficit: 52.5 52.8 52.7 52.8 52.3 52.6 41.5 at 0.60 ft/yr 69 69 69 69 69 69 69 Excess or Deficit: 63.9 64.2 64.1 64.3 63.7 64.0 53.0 Ground WateT Supply Protection and Management Plan for the Eastern Shore of Virginia E-4 Recharge to the Yorktown-Eastover (Confined) Aquifer DERIVATION OF THE RECHARGE EQUATION WEST ICentraJ Plateau I EAST Chesapeake PRECIPITATION Atlantic Be, Ocean Water Table Plezornetric Level jxx w. . ............ ........... S I Salt Ground Water Water L El 4sh Water Aquffer zoo El Fresh Water Aquitard x=U2 The governing differential equation for steady state flow in one dimension is: d 2h/dX2 = -w/T. (1) where h = the hydraulic head of the Yorktown-Eastover aquifer, x = the lateral distance from the center spine of the peninsula (always positive), w the recharge rate of the Yorktown-Eastover aquifer, T the transmissivity of the Yorktown-Eastover aquifer, and L width of the peninsula. Integrating once, the equation becomes dh/dx = (-w/T)x + C1. (2) At the ground water divide, x = 0 and dh/dx = 0. Substituting these values into equation (2) results in the following equation, upon which the constant C, can be solved for: 0 = -w/T(O) + C 1 C, = 0. Integrating again, the equation becomes h = (-w/2T)x2+ C 1x + C2. (3) Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia E-5 I I I I I BUILDOUT NITROGEN LOADING CALCULATIONS APPENDIX F I I I I I I I I I I I I I I Table F-1: WPA (A) Future Nitrogen Loading Calculations NITROGEN LA)ADING CALCULATIONS WPA A Future (spine only, all soils) INPUT FACTORS Number of Residential units 379 Sewage flow per house (galiday) 163 Commercial/Industrial land (Scres) 60 ComAnd. sewage flow per scre 423 N-conc. in sewage effluent (mg/1) 40 lawn am per house (square fed) slow Pavement per house (square fed) 3W Road arm (square fee) IA5Io040 Roof area per house (square fed) Lsw Agricultund area (acres) U59 Landfills (acms) 0 Septage lagoons (gallonstyr) 0 Septege N concentration (mg1l) 43 Animal burial (Ibs /yr) 222,081 Total recharge area (acres) 3,417 Reduage rate for pervious 17 area fin/yr) Recharge rate for impervious 34 area (in/yr) INPUT CALCULATIONS RESULTS Sewage (galiday) CALCULATED LA)ADING (LBSNR) 120,915 x N-conc (mg/1) x 3.785 1/gal x 365 days/yr: 4M000 rng/lb 14,715 Lzwn area (sq ft) U9510W x O.OOD9 lb Nlsq It 2,606 Pavement area (sq ft) 1,7",340 x O.OOMI lb N/sq ft 549 Roof area (ag ft) 868,5W x 0.00015 lb N/sq ft 130 Natural area (acres) 871 x 43560 aq ft/acre x 0.000005 lb Nlaq ft 190 OkherSource3 Agriculture (acres) 2,3" x 89 lbs N/acre/yr x 25% leaching rate 32,492 L.andfills (acres) 0 1184 lbsN/acre/year 0 Septage I.Agoons (X&Vyear) 0 x N-conc (rng/1) x 3.795 1/gal: 454000 rng/lb 0 Animal brurial (lbs/yew) 222,081 x 33 % N concentration 7,329 TOTAL NITROGEN LDADING (LBS/YR) 78AM TOTAL RECHARGE (MGrYR) techaige from sew/*!Ptage (gal/day 120,91, x 365 days/yr: 1,000,000 gal/million gal -- 44 Total pervious ares (sq ft) 140",680 x 17 in/yr /12 in/ft x 7AS gal/cu ft: 1,000,000gal/million gal 1,335 Total impervious am& (ag ft) 3,945,340 x 34 in/yr /12 in/ft x 7.48 gal/cu ft: I,000,000gal/million gal TOTAL RECHARGE (MGALJYR) 7OTAL NITROGEN LOAD/TOTAL RECHARGE X &IA000 MG/LB: 3,795,000 L/MGAL I =RECHARGE NfTROGEN CONCENTRATION (W orppm) PREPARED UY HORSLEY WITTEN HEGEMANNo INC. F-I Table FL2. WPA (A) Future Nitrogen Loading Calculations - Developable Soils Only NITROGEN LOADING CALCULATIONS WPA A Future (spim: only, Arapahoe sails; considered undevelopable) INPUT FACTORS Number of Residential units 27 Sewage flow per house (plldwf) 1 165 Cimurwdalifindustrial land (mcrm) 1 60 ComAnd. sevoge Dow per acre 1 423 (Sal/day) N-amc.insewag effluent(W611) 40 Lawn area per house (squane fast) 5,000 Pavement per house (square feell SDO Road area (square feet) 2AB1,040 Roof am Pat house (square feed I 1AW Agricultunal area (acres) 2,819 Landfills (acres) 0 Septage lagoons (gallonad" a 77= Septage N concentration (nM 45 --7= Animal burial (lbs tyr) 222,081 Total recharge area (scres) 3,417 PAVhWze rate for Pervious 1 17 am& finlyr) Recharp oft far [email protected] 34 am (intyr) INPUT CALCULA77ONS RESULTS Sewage (gal/day) CALCULATED LOADING (LBS/YR) 29,835 x N-cmC(mA/l) x 178511a x 365 days/yr: 45M mA/lb 3,632 Lawn area (ag ft) IM,000 xD.MlbN/sqft U2 Pavement ma (sq ft) 1,494,50 x O.ODD42 lb N/sq ft Roof ar" (sq it) K500 x Q00015 lb N/sq ft 6 Natural am (acres) 499 x 43560K ft/aue x 0.000005 lb?,J/sq it 109 Other Sources Agricultutv (scres) [email protected] x 89 lbs N/acre/yr *M S leach 62.733 Landfills (acres) 0 1184 lbaN/acre/year 0 Septalte Lagoons (gavvem 0 x N-cmc (mg/1) x 3.785 1 kal: 45M MR/lb 0 Animal burial UWyear) 222,081 x 3.3 % N concentration 7,329 TOTAL NITROGEN LOADING (LBS)YR) 7OS7 TOTAL RECHARGE (MGIM techarge fion, sew/septaxe (Ral/day 29,835 x 365 days/yr: 1,000,0DO gal/million gal 11 Total pervious ants, (sq ft) ODD W/rndbcn A&I 1,%7 146,002,660 X171n/yr/12in/ x7.48gal/cuft:l Total impervious area, (Ig ft) x 34 in tr /12 in/ft x 7.48 gal 1cu ft: 1,0m,= gal/million gal 60 TOTAL RECHARGE (MGALJYR) 1,618 !UFAL -NrrRocEN LOAD GE X 454,0DI) MG/ 1.11: 3,755,UUU LIMUAL - . [email protected]@@ARGE NITROGEN CONCENTRATION (we or PPIT01 5.5 PREPARED BY HORSLEY WITTEN HECEMANN, INC. F-2 Table F-3k WPA (B) Future Nitrogen Loading CAlculatiMs NITROGEN LOADING CALCULATIONS WPA 0 Future (spine only, all sails) INFUTFACTORS N wil- of Residential units IXM ---- 777= Sewap flow per house (sal/clay) 1 165 7777= Cunercialndustrial land (acrea) 692 C=L/Ind. sewage (lam per me 423 7777= (Sal/day) Noconc, in sewage effluent (ngd) 40 Lwvmaveaperl (square feet) 51000 Paremen perhoupe(equarefeitt) SDO Road area (square feet) 2.IX440 Pod am per house (square feed LAM Agricultural areat (acres) 2,3314 Landfills (acres) Lo Septale lagoons (gallonstyr) 430,WO S.pug. N concentration (m&M 1 43 Animal burial (lbo lyr) 319,449 Total recharge area (acres) 4,915 Recharge rate for pervious 17 area (in/yr) Recharge rate for invevious 34 area fintyr) INPUT CALCULATIONS RESULTS Sew.g. ([email protected]/d.y) CALCULATED LOADING (LBSrAU 496,656 x N-conc(mg/l) x 3.7851/a x 365 days/yr: 45M mA/lb 60,4S3 [email protected] am (sq ft) 6,180,0w x OjM lb Wag ft avement area (sq fo 2.7S2.440 . CLOOD42 lb N /,q ft 1.156 Roof area (sq ft) I.&%1000 x 0.0001S lb N/sA ft 278 Natural area (acres) 1,492 x 43560 sq ft/acre x 11000005 lb N/sq ft 325 Other Soumes Apgriculture (acres) 2,334 x 89 lbs N/acre/yr * 25 S leach SL934 Landfills (so") ISO 1134 lbsN/acre/year 177,IM SeptaSt Lagoons (gat/year) 450,000 x N-conc (mg/O x 3.7851/0:45M mg/lb 244 Animal burial (lbs/y-) 319,449 x 3.3 % N concentration 101S42 TOTAL NITROGEN LOADING (LBSfYR) 307,620 TOTAL RECHARGE(MG/YR1 techarge from sew/wptage (gal/clay) 4%,656 x 365 da)%/yr: 1,000,ODO gallmillion a 292 Total peMous arza leg ft) 187,"2,624 x 17 in/yr /12 in/ft x 7.48 ital/m ft: LOMAOD Total unpMcaz area (sq ft) 26,194,776 x 34 in/yr /12 in/ft x 7.48 gal /cu ft: 1,0M,W0 gal/million gal 555 i TOTAL RECHARCE(MGALIM! 2,728 TOTAL NITROGEN LDAD/TOTAL RECHARGE X 454,000 MG/LB:3795,000 L/MGAL r --RE(3iARCE NITROGEN CONCENTRATION logo orppadl 13.5 71 PREPARED BY HORSLEY WITTEN HECEMANN, INC. F-3 Table FL4: WPA (B) Future Ni"ert Loading Calculations - Developable Solls Only NITROGEN LOADING CALCULATIONS WPA 5 Fubim (spine only, Arapahoe scils, considered undevelopable) INPUT FACTIORS NM,ba of RdddW units 1.211 Sewage Rorie per boast (gal/day) 165 ConumercialrInduontal land (acres) 1 622 --77= ComAnd. sewage Russ, per am 1 423 (gal/day) N-conc. in sewage effluent WS11) 1 40 77= Lawn am parl (MIumefew I SAM- Pavement per house (square: feet) Soo Road am (minare fect) 2,12MAW Roof arem per house, (square 11NO I IAM Agricultural am facres) 2.3SS Landfills (acres) IM 77== Septage lagoons (gallons/yr) 450,M0 -- -771 Septage N comcamtradon (n*4) 45 Aninial burial (lbs lyr) 319,449 777= ToW recharge am (acres) 4,915 77= Redurge rate for perviorms 27 am (ir-jyr) Recharge rate far imopervious 34 me (intyr) INPUT CALCULATIONS RESULTS Sewage (X&Vday) CALCULATED LOADING (LBSIM 4W31 x N-conc (mg/1) x 3.7951/gW x 365 days/yr: 45M mgAb 59,951 Lmn area (og ft) 6,055,000 x O.OW9 lb N /sq ft S,00 Pavexnent me (mg it) 2,739,940 x 110OD42 lb N/aq ft 1,151 Roof am (ag ft) 11816,SOD x0.0DDISJbN/sqft-- 272 Natural area 4acres) 1,474 X43%Osqft/acrex 0.000DOMN/sqft 3.21 Other Sources Agriculture (acres) V55 x 89 lbs N/scre/yr * 25 % leach 32,407 LandfWs (acres) L5 a 1184 lbsN/acre/year Septage Lagoomms, (gally,") 450,000 x N-conc(mg/l) x 3.7851/gal: 450M mg/lb 2" Animal burial (lbs1year) 319,449 x 3.3 % N concentration 10sa TOTALNITR CENIDADINC(LBSrYR) 307,463 tarchame hm sewlseptaite fitaIV/da TOTAL RECHARGE (MG/M 492,M x 365 dayg/yr: 1,000,ro RAI /mflhm gal ISO Total pervious we's (ag ft) 187,952,624 x 17 in/vt /12 in/ft x 7.48 gal /cu ft: 1,000,000 1,"2 Tvial unpamous am (sq ft) 26,144,776 x 34 in/T-/12 -m1ft . 7.48 gal /cu ft: IAM,000 PI / on gal S54 TOTAL RECHARGE (MCAL/M 2,72 TOTAL NITROGEN LOAD/TO`rAL RECHARGE X 454,000 MG/LS: V85,000 L/MCAL I -REC3iARCENITROCENCONCEhrrRATION(nwAorppnOi 13S PREPARED BY HORSLEY WITTEN HECEMANN, INC. da407 F-4 Table F-&WPA (C) Future N*trogm Lzading Calculations NITROGEN LOADING CALCULATIONS WPA C Future (opine only, all and*) INPUTFACTORS Number of Reeldential units 10,137 Sewage flowperhouse(gal/day) Ms 777= Comme7cialfIndustrial land (acres) 110" ComJInd. wwap flow per am 423 (Sal/day) N-cont. in sawage effluent (mg1l) 40 Lawn area per house (square feW 5,0M Pavemartf, per I (equare two SM Road ares (square feet) 41123812W Rod am per house (square feet) 1AM Agricultural area (acrea) 2A29 Landfills (acres) a S"Se lagoons, (gallonslyr) 0 Sepuge N concentration (n*A) 45 Animal burial (lbs tyr) 618,M4 Total mduwgt area (acres) 9AM Redutrge rate for pervious 27 area (intyr) Reduarp rate for impervious 34 am& finlyr) INPUT CALCULATIONS RESULTS Sewage (gallday) CALCULATED LOADING (LBS/YR) 2,U5,977 x N-conc(mg/l) x 3.7851/0 x 365 days/yr: 454000 mgAb 259,"4 L.awn am (eq ff) S0,733tooo x 0.0009 lb Nlag ft 45,707 pave-iont area (ag ft) 9,216,700 x O.ODD42 lb N/sq ft 3,871 Roof arva (sq ft) 13,235,5M x OLM015 lb N /eq ft 2,285 Natural area (acres) 4,089 x 43560 sq ft /acre x MOOM lb N /sq ft 991 Other Sources Aoculture (acres) [email protected] x 89 lbs N/acre * 25 Meach 56,496 Landfills (acres) 0 1164 lbs N/acre/year 0 Septage Lazoorts fitallyear) 0 x N-conc(mg/b x &7951/gal: 45=mg/lb 0 Animal burial flbs/year) 618,024 x 3.3 % N conceritrartion 20,39S TOTAL NITROGEN LOADING (LBS/YR) 3M,419 techarx fmm sawfeeptage (gal/da --- TOTALRECHARCE(MGfM xU5,9" x MS days/yr: 1,00DODD A&I tmilbon gal 776 Total peMous am log ft) 366,%S,920 x 17 m/yr /12 m/ft x 7.48 Ael /M ft: 1,000,0DO ghl/ndllion gal 3ASS Total impervious area (ag ft) 47A26,220 x 34 in/yr /12 in/ft x 7.48 gallcu ft: 1,ODD,000 W/-.Mlb-Sl 1.009 TOTAL RECHARGE (MCAUYR)l 4670 ITUTAL NITROGEN LOAD/7%)TAL RECHARGE X 451,0M MG/LB: 3,795,00D L/MGAL r --REGiARGE NITROGEN CONCENTRATION (mew ppm)j 1-3 PREPARED BY HORSLEY WITTEN HEGEMANN, INC F-5 TaWe F-4k WPAM Future Nitrogen Loading Calculation* MTROGEN LOADING CALCULATIONS WA D Putm (spine only, all wils) INPUT FACTORS Number of Residential units =96 Sewage flow per house (gaivday) 1 265 Cammummciallindustrial twd (acrem) 1 325 777= CamAnd. sewage flow par acre 423 (Sal/day) N-anw.insew efftment(wo) 40 Lown am per house (square feed 5,000 7-== ptseusent P. house (.F. faso 500 Road am (scItuat feet) 4,530,240 Red am per house (square, I" IAW Agdcultural am& (acres) IA73 --7=7= Landfills; (acres) 0 Sertase as- (gallons" 0 Sepiage N concentration (=%4) 45 Aninw bmial ubm lyr) 6-M-0-m Total recharge arta (acres) 106431 777= Recluarse rate for parvious 17 am unlyr) Recluerge rate for iznporvious 34 777= area fir.),r) INPUT CALCULATIONS RESULTS Sewage (Sal/day) CALCULATED LOADING (LBSIM ZM,915 x N-cmc (mit1l) x S.7851 la x 365 days/yr: 456(= mptAb 2",M La" area lag ft) 61,460,WO x 0.0009 lb N/aq ft S51m Pavemmt area (ag ft) 4,455 10,679,240 x a0W42 ]b N/sq ft Roof area tiq ft) 18,"4,0D0 x 0AW15 lb Wag ft 2,767 Natural area (screw 6,IS3 x 43560,q ft/.- . 0.0000M lb N /,q ft I_U0 Other sources Agriculture lacres) L673 x 84 lbs N/acre x 25 % leach 35,1" Landfills (acres) 0 1184 lbsN/acre/year 0 Septage Lagoons (gallycar) 0- xN-amc(MR/I)-3,'SSI/A&1:454OWmA/lb 0 Animnal burial (lbstrw) 22,372 677,9" x 3.3 % N concentration TOTAL NITROGEN LOADING (LBStYR) M,407 TOTAL RECHARGE(mcfm tech . fivot me-Imptage gnal/da I'm,915 x 365 days/yr: IAW,000 0/million FAJ 822 Total pervious arva log ft) 413,817,620 x 17 in/yr /12 in/ft x 7A$ sal/cu ft: 1,0W,000 salloWbon As] 4,MS Total impervious avem (ag ft) 40,556,740 x 34 in/vr /12 in/ft x 7.48 Sallcu ft: 1AW,= no TOTAL RECHARGE(MGERZ4 6,066 TOTAL NITROGEN IDAD /TOTAL R ECHARGE X 454,000 MG/ LD: 3,73,,,mu L/ MGAL T RECHARGE N rrROCEN CONCENTRATION (vall or Ppu%)l --7.3 PREPARED BY HORSLEY WITTEN HEGEMANN, INC F-6 TaWe F-7., WPA( E) Future Nitrogen Loading Calculations NITROGEN LOADING CALCULATIONS WPA E Future (spine only, all soils) INPUT FACTORS Number of Residential units L%409 Sevem" fiovr per house (Sal/day) 165 Cartursercial/Industrial land (acres) 1 239 777= ComAnd. sewage flow per am 423 (Sal/day) [email protected] in sevrage effimmi (u%fi) 40 777= Lawn am per house (square feW 1 5,000 Pavement per home (square feed I Soo Road am (square feet) 4,704o48D Roof am per house (square feel) IAW Agricultural am (acres) M Landfills lacres) 0 Septage lagoorti, (gatlanslyr) 0 Septage N concentration WV) 45 AWmal burial (lbs 1yr) 0 Total recharge am& (acres) 10,7% Reduirge rate for pervious 17 area finlyr) Recharp rate for [email protected] 34 7-77= area Unlyr) INPUT CALCULATIONS RESULTS Sewage ([email protected] CALCULATED LOADING (LBS/YR) 2,313,582 x [email protected](mg/]) x.1785 lIpA x 365 days/yr: 454= mg/ib 281,610 Lawn area (sq it) 67,045,ODO xO.0009lbN/sqft -60,341 ravcvvmt area (59 it) 11,408,980 x CL00042 lb N /ag ft 4,792 Roof ama (sq ft) 20,113,500 x 0.00015 lb N /sq ft _.%017 Natural am& (acresl 7,567 x43%0sgft/acmx0L00Wffi1bN/*gft Other Sources Aoculture (acres) 728 x 79 lbs Nlacre x 25 % leach 14,370 Landfills (acres) 0 1164 IbBN/acre/year 0 SeptaRe LaXoons ggal/year) 0 x N-cDnc (mit/1) x 3.795 1 /gal: 4MM MA/lb 0 Animal burial (lbstywr) x 3.3 % N concentration 0 TOTAL NITROGEN LOADING (LBSfYR) 365,777 -TOTAL RECHARGE(MG/M techarge from newlseptalle (Ital/day 2,[email protected] x 365 days/yr: I,0W,0D0 stal/mMon gal 8" Total perrious, ama (ag it) 433,54S,860 x 17 in /yr /12 in/ft x 7.48 gal /cu ft: I,OM,000 Aal/ffdlhm A&I 094 Total impervious ama (ag ft) 36,727,WD x 34 m/yr /12 in/ft x 7.48 Aal/cu ft: 100,000 0/millian gal 778 i TOTAL RECI iARCE(MC 6,217 TOTAL NITROGEN LOAD/TDTAL RECHARGE X 4M,M0 MC/LB: 3,795,000 L/MCAL T ---OiARGENrrROCENCONCEN"rRATION(nVAwppWI 7.1 PREPARED BY HORSM VVITTEN HEGEMANN, INC F-7 I I I I I REFERENCES AND RESOURCES APPENDIX G I I I I I I I I I I I I I I REFERENCES Andreoli, A., et al. 1979. Nitrogen Removal in a Subsurface Disposal System. Journal of Water Pollution Control Federation, 51, 4. Association of Ground Water Scientists and Engineers. Proceedings of Ground Water Issues and Solutions in the Potomac River Basin/Chesapeake Region. Washington, D.C.: George Washington University, 1989. Bacon, P.E. and Freney, J.R. 1989. Fertilizer Research. Vol. 20:2, P. 59-66. Bal, Ganesh P. 1977. Computer Simulation Model for Groundwater Flow in the Eastern Shore of Virginia. Virginia State Water Control Board. Planning Bulletin 309. 63 p. Bennett, G.D., M.J. Mundorff, and S.A. Hussain. 1968. Electric-Analog Studies of Brine Coning Beneath Freshwater Wells in the Punjab Region, West Pakistan. USGS WSP 1608-J. 31 pp. Bock, B.R. 1984. Efficient Use of Nitrogen in Cropping Systems. In Nitrogen in Crop Production, R.D. Hauck (Ed.) p.273-277. Bourna, J., W.A. Ziebell, W.G. Walker, P.G. Olcott, E. McCoy, and F.D. Hole. 1972. Soil Absorption of Septic Tank Effluent. University of Wisconsin-Ext. Geol. Natural History Survey Information Circular No. 20. Bouwer, H. 1989. Nitrogen Management and Groundwater Protection. R.F. Follett (Ed). Elsevier Science Pubs. p. 363-372. Brandes, M. 1978. Characteristics of Effluents from Gray and Black Water Septic Tanks. journal of Water Pollution Control Federation. Brown, K.W., R.L. Duble, and J.C. Thomas. 1977. Influence of Management and Season on Fate of Nitrogen Applied to Golf Greens. Agronon-dc Journal 69:667-671. Brown, K.W., J.C. Thomas, and R.L. Duble. 1982. Nitrogen Source on Nitrate and Ammonium Leaching and Runoff Losses From Greens. Agronon-dc Journal. 74:947-950. Canter and Knox. 1986. Septic System Effects on Ground Water Quality. Chichester. 1977. Effects of Increased Fertilizer Rates on Nitrogen Content of Runoff and Percolate From Monolith Lysimeters. Journal of Environmental Quality. 6:211-217. Colman, S.M., J.P. Halka, C.H. Hobbs, 111, R.B. Mixon and D.S. Foster. 1990. Ancient Channels of the Susquehanna River Beneath Chesapeake Bay and the Delmarva Peninsula. GSA Bulletin 102. pp. 1268-1279. Douglas, D.F. 1986. Literature Review of the Cumulative Impact of On-site Sewage Disposal Systems on Nitrate Nitrogen Concentrations in Ground Water. State of Vermont, Department of Water Resources and Environmental Engineering, Ground Water Management Section. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia G-1 Dowdell & Webster. 1980. A Lysimeter Study Using Nitrogen-15 on the Uptake of Fertilizer Nitrogen by Perennial Ryegrass Swards and Losses by Leaching. journal of Soil Science 31:65- 75. Dudley, J.G., and D.A. Stephenson. 1973. Nutrient Enrichment of Ground Water From Septic Tank Disposal Systems. Inland Lake Renewal and Shoreline Management Demonstration Project Report. University of Wisconsin, Madison. Dunne, T.D. and L.B. Leopold. 1978. Water in Environmental Planning. W.H. Freeman and Company. New York. 817 p. Fennema, Robert J. and Virginia P. Newton. November, 1982. Ground Water Resources of the Eastern Shore of Virginia. State Water Control Board Planning Bulletin 332. 74 p and Appendices. Freeze, A., and J. Cherry. 1979. Groundwater. Prentice Hall, Inc., New Jersey. Glover, R.E. 1959. The Pattern of Fresh-Water Flow in a Coastal Aquifer. Journal of Geophysical Research. Vol. 64, No. 4. pp. 457459. Ground Water Pollution News. Buraff Publications (BNA). May 25,1989. Ground Water Quality Protection, State and Local Strategies. Washington, D.C., National Academy Press, 1986. Hesketh, E.S. 1986. The Efficiency of Nitrogen Use by Kentucky Bluegrass Turf as Influenced by Nitrogen Rate, Fertilizer Ratio and Nitrification Inhibitors. M.S. Thesis, Univ. Rhode Island, Kingston, RI. Hubbard, R.K., Gascho, G.J. Hook, J.E. and W.G. Knisel. 1986. Nitrate Movement into Shallow Ground Water Through a Coastal Plain Sand. Trans of American Society of Agricultural Engineers. St. Joseph, Mich. Nov/Dec. p. 1564-1571. Howie, B., and B.G. Waller. 1986. Chemical Effects of Highway Runoff on the Surficial Aquifer, Broward County, Florida, USGS WRIR 864200. Keeton,W.T. Biological Science. 3rd Ed. WW Norton & Co. NY 1980. Koppelman, L.E. 1982. Long Island Segment of the Nationwide Urban Runoff Program, Long Island Regional Planning Board, Hauppauge, N.Y. Kroehler, Carolyn. What Do The Standards Mean?: A Citizens' Guide to Drinking Water Contaminants. Blacksburg, VA: Virginia Tech, Virginia Water Resources Center. Laak, R. 1980. Characteristics and Quantity of Wastewater. In Wastewater Engineering - Design for Unsewered Areas. Ann Arbor Science Publishers, Inc. Laak, Rein. 1986. Wastewater Engineering Design for Unsewered Areas. Lancaster, PA: Technomic Publishing Co., Inc. Lager, et. al. 1968. Urban Stormwater Management and Technology: Update and Users' Guide. USEPA, 68-03-2228. Ground Water Supply Protection and Manage?nent Plan for the Eastern Shore of Virginia G-2 Loehr, R.C. 1974. Characteristics and Comparative Magnitude of Non-point Sources. journal of Water Pollution Control Federation, 46(8). Magdoff, F.R., D.R. Keeney, J. Bourna, and W.A. Ziebell. 1974. Columns Representing Mound-type Disposal Systems for Septic Tank Effluent: 11. Nutrient Transformations and Bacterial Populations. Journal of Environmental Quality 3(3):228-234. Majumbar, S. Miller, E., and R. Parizek, eds. 1990. Water Resources in Pennsylvania: Availability, Quality, and Management. Easton, PA: The Pennsylvania Academy of Science, pp. 334-353: Dale E. Baker and Donald Crider, "The Environmental Consequences of Agriculture in Pennsylvania". Mancino, C.F. 1983. Studies of the Fate of N03- and NH4+ Nitrogen From Various Fertilizers on Turf9rasses Grown on Three Different Soil Types. M.S. Thesis, University of Massachusetts- Amherst. McWhorter, D.B. 1972. Steady and Unsteady Flow of Fresh Water in Saline Aquifers. Water Management Technical Report 20. Colorado State University. Fort Collins, Colorado. 49 p. McWhorter, D.B. and D.K. Sunada. 1977. Ground-Water Hydrology and Hydraulics. Water Resources Publications. Littleton, Colorado. 290 p. Metcalf & Eddy, Inc. 1979. Wastewater Engineering: Treatment Disposal Reuse. McGraw Hill, Inc. Miller, David W., ed. Waste Disposal Effects on Ground Water. Berkeley, California: Premier Press, 1980. Morton, T.G., A.J. Cold, and W.M. Sullivan, 1988. Influence of Overwatering and Fertilization on Nitrogen Losses from Home Lawns. journal of Environmental Quality. 17(l):124-130. Nelson, K.L., A.J. Turgeon, and J.R. Street. 1980. Thatch Influence on Mobility and Transformation of Nitrogen Carriers Applied to Turf. Agronomy Journal 2:487492. Nelson,M.E., S.W. Horsley, T.C. Cambareri, M. Giggey, and J. Pinette. 1988. Predicting Nitrogen Concentrations in Ground Water-an Analytical Model. Proceedings of the National Water Well Association, Stamford, Connecticut. Owens, L.B. 1990. Nitrate-Nitrogen Concentrations in Percolate from Lysimeters Planted to a Legume-Grass Mixture. journal of Environmental Quality. 19: 1, 131-135. Petrovic, A.M. 1988. Late Fall Fertilizing and Ground Water Quality. Landscape Management, 1988:64. Porter, K.S. 1978. Nitrates in the Long Island Comprehensive Waste Treatment Management Plan: VII Summary Documentation. Long Island Regional Planning Board, Hauppauge, New York. Reilly, T.E. and others. 1987. Analysis of Steady-state Salt-water Upconing with Application at Truro Well Field, Cape Cod, Massachusetts. Ground Water, Vol. 25, No. 2. pp. 194-206. Reneau, Jr., R.B. 1977. Changes in Inorganic Nitrogenous Compounds From Septic Tank Effluent in a Soil With Fluctuating Water Table. journal of Environmental Quality, 6(2):173-178. Ground Wat er Supply Protection and Management Plan for the Eastern Shore of Virginia G-3 Richardson, Donna L. 1991. Hydrogeology and Analysis of the Ground-Water-Flow System of the Eastern Shore Peninsula, Virginia. Unpublished, provisional draft copy of USGS WRI 91- xxxx. Ritter, W.Rand , 1985. Effect of Irrigation Efficiencies on Nitrogen Leaching Losses. journal of Irrigation and Drainage Engineering. Vol III, No.3. Robertson, W.D., Cherry, J.A., and E.A. Sudicky. 1991. Ground-Water Contamination from Two Small Septic Systems on Sand Aquifers. Ground Water: Vol. 29, No. 1, Jan-Feb 1991, p. 82-92. Schmidt, S.D., and D.R. Spencer. 1986. The Magnitude of Improper Waste Discharges in an Urban Stormwater System. Journal of Water Pollution Control Federation, 58(7). Sinnott, Allen and G. Chase Tibbitts, Jr. 1968. Ground-Water Resources of Accomack and Northampton Counties,Virginia. Virginia Division of Geology. Mineral Resources Report No. 9. 113 p. Starr, J.L., and H.C. DeRoo. 1981. The Fate of Nitrogen Fertilizer Applied to Turf. Crop Science, 21:531-536. Thornthwaite, C.W. and J.R. Mather. 1955. The Water Balance. Laboratory of Climatology. Publication No. 8. Centerton, New Jersey. U.S. Environmental Protection Agency. National Water Quality Inventory, 1988 Report to Congress. April, 1990. U.S. Environmental Protection Agency. On-Site Wastewater Treatment and Disposal Systems Design Manual. 1980. Valiela, I., and J. Costa. 1988. Eutrophication of Buttermilk Bay, a Cape Cod Coastal Embayment: Concentrations of Nutrients and Watershed Nutrient Budgets. Environmental Management, 12(4):539-553. Virginia Water Project, Inc. Water For Tomorrow. Roanoke, VA: 1988, pp. 39, 101. Weigmann, Diana L. and Carolyn J. Kroehler. 1988. Threats to Virginia's Ground Water. Blacksburg, VA: Virginia Tech, Virginia Water Resources Research Center. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia G4 RESOURCES REVIEWED Accomack County Comprehensive Plan, 1989. Accomack County Land Use Maps, 1986. Accomack County Land Use Summary (1986). Accomack County Listing of Subdivisions. Accomack County Map of Subdivisions. Accomack County Tax Map Listing of Incorporated Towns. Accomack County Tax Maps (1986). Accomack County Zoning and Subdivision Ordinance. Accomack-Northampton Planning District Commission. Locations of Farm Ponds for Accomack and Northampton on Quadrangle Scale Maps. Building Permit Data. Northampton County Comprehensive Plan, 1990. Northampton County Extension Service. Farm Pond Locations on Quadrangle Scale Maps. Northampton County Housing Survey and Population Projection, 1988. Northampton County Listing of Subdivisions. Northampton County Zoning Ordinance, 1983. Soil Conservation Service, 1990. Classification and Correlation of the Soils of Accomack County, Virginia. October, 1990. Soil Conservation Service. Hydrologic Unit Maps of Accomack and Northampton Counties. 1:126,720 scale. Soil Conservation Service (United States Department of Agriculture). Soil Survey of Northampton County, Virginia. August, 1989. Virginia Bureau of Toxic Substances Information. Commercial Use of Substances by Establishment, Accomack and Northampton Counties. Virginia Department of Agriculture. Virginia Pesticide Law and Regulations, 1986. Virginia Department of Agriculture. Restricted Use Pesticides, 1990. Virginia Department of Agriculture and Conservation Service. Pesticide Use Estimate 1990. Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia G-5 Virginia Department of Health. Base Line Water Quality Study of Shallow Wells in Northampton and Accomack Counties, April 1990. Virginia Department of Health. List of Transient-Public Water Users. Virginia Department of Health. Listing of Migrant Labor Camps. Virginia Department of Health. Map of Migrant Labor Camp Locations. Virginia Division of Geology. Summary of Geology and Ground-Water Resources of the Eastern Shore Peninsula, Virginia, A Preliminary Report. Mineral Resources Circular No. 2,1954. Virginia Division of Mineral Resources. Geologic Studies, Coastal Plain of Virginia, Bulletin 83 (Part 3), 1973. Virginia Division of Mineral Resources. Ground-Water Resources of Accomack and Northampton Counties, Virginia Mineral Resources Report No. 9,1968. Virginia State Water Control Board. Computer Simulation Model for Groundwater Flow in the Eastern Shore of Virginia, Planning Bulletin 309, 1977. Virginia State Water Control Board. Eastern Shore Water Supply Plan. Planning Bulletin 342, March 1988. Virginia State Water Control Board. Groundwater Conditions in the Eastern Shore Groundwater Management Area, Virginia. Planning Bulletin 45, Supplement No. 2 Virginia State Water Control Board. Groundwater Conditions in the Eastern Shore of Virginia. Planning Bulletin 45, December 1975. Virginia State Water Control Board. Ground Water Resources of the Eastern Shore of Virginia. Planning Bulletin 332, November 1982. Virginia State Water Control Board. Virginia Eastern Shore Water Quality Management Plan, 1980. Virginia State Water Control Board. Virginia Livestock and Poultry Water Use Basic Data. Bulletin 60, 1983. Virginia Tech. Hydric Soils Maps. 1:100,00 scale. Virginia Tech, Virginia Water Resources Research Center. Facts About Virginia's Groundwater, 1988. Virginia Tech, Virginia Water Resources Research Center. A Groundwater Primer for Virginians, 1984. Virginia Tech, Virginia Water Resources Research Center. A Homeowner's Guide to Domestic Wells, 1985. Virginia Tech, Virginia Water Resources Research Center. A Homeowner's Guide to Septic Systems, 1985. .Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia G-6 Virginia Tech, Virginia Water Resources Research Center. Listing of Mass Drainfields on the Eastern Shore, 1985. Virginia Tech, Virginia Water Resources Research Center. Protecting Virginia's Groundwater, 1986. Virginia Tech, Virginia Water Resources Research Center. Sandcastles, Moats, and Petunia Bed Holes, a Book About Groundwater, 1986. Virginia Tech, Virginia Water Resources Research Center. Threats to Virginia's Groundwater, 1988. United States Bureau of the Census. 1990 Population Figures. United States Geological Survey. Groundwater Quality Assessment of the Delmarva Peninsula, Delaware, Maryland, and Virginia-Analysis of Available Water Quality Data Through 1987. Open File Report 89-34, 1989. Wallops Island Well Boring Logs, Impact Statement (2 documents). Ground Water Supply Protection and Management Plan for the Eastern Shore of Virginia G-7 I i I I I i I I I I I I I I I I I I I - I - -3 6668 -14100 9144 1 @