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cr Battery * ~1983 WATER SUPPLY STUDY U ~~~CITY OF HOMER, AK 'COASTAL Zo? 1'NFORIMA I11 I~~~~~~~~~~~~~~~~~jiSAV I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~i 3 ~~~~~~~~~BY OLYMPIC ASSOCIATES CO. I ~P.O BO 31-0 ARCTIC BUSINESS PARK, SUITE 102 EXITER AVE o 71W.41tAE 5686 EWA 80 ANHRGA950 W38 W383 K OEBR1983 1983 WATER IMPROVEMENT STUDY FOR CITY OF HOMER, ALASKA propez:t� of CSC 1' bI&.f ~~~~~~~0I C Prepared by OLYMPIC ASSOCIATES CO. 1391 Dexter Ave. North 701 West 41st Avenue Seattle, WA 98109 - Anchorage, AK 99503 U.S. DEPARTMENT OF COMMERCE NOAA COASTAL SERVICES CENTER 2234 SOUTH HOBSON AVENUE CHARLESTON , SC 29405-2413 "The preparation of this study was financed in part by funds from the Office of Coastal Zone Management, National Oceanic and Atmospheric Administration, U.S. Department of Commerce, administered by the Division of Local Government Assistance, Alaska Department of Community and Regional Affairs. -YA November 1983 1W~~~C ,2~c Tm WATER IMPROVEMENTS STUDY CITY OF HOMER, ALASKA Table of Contents TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES SECTION I FUTURE WATER REQUIREMENTS & SUPPLY ALTERNATIVES Page 1.0 INTRODUCTION 1-1 1.1 General 1-1 1.2 Scope of Work 1-1 1.3 Results of the Study 1-2 1.4 Study Source Locations 1-3 2.0 WATER DEMAND 2-1 2.1 General 2-1 2.2 Existing Demand 2-1 2.3 Future Demand 2-4 3.0 ASSESSMENT OF GROUNDWATER SUPPLIES 3-1 3.1 Background 3-1 3.2 Occurrence of groundwater 3-1 3.3 Use of groundwater 3-5 4.0 ASSESSMENT OF DISTANT SURFACE WATER SUPPLIES 4-1 4.1 Sources of supply 4-1 4.2 Utilization of China Poot Lake 4-2 5.0 ASSESSMENT OF REVERSE OSMOSIS (DESALINATION) FEASIBILITY 5-1 5.1 Background 5-1 5.2 RO technology 5-2 5.3 Application of RO technology to Homer 5-3 5.4 Conclusions 5-4 6.0 HYDROLOGY 6-1 6.1 General 6-1 6.2 Methodology 6-1 6.3 Precipitation and temperature data 6-2 6.4 Stream flow data 6-5 6.5 Evaporation data 6-7 6.6 Calibration of Anchor River catchment 6-7 Page 7.0 ASSESSMENT OF SURFACE WATER SUPPLIES 7-1 7.1 General 7-1 7.2 Anchor River/Beaver Creek 7-3 7.3 Bridge, Fritz and Twitter Creeks 7-4 7.3.1 Simulation of Daily Flows: Twitter Creek and Bridge Creek 7-5 7.3.2 Estimation of Daily Flows: Fritz Creek 7-5 7.3.3 Conclusions 7-5 8.0 REGIONAL GEOLOGY 8-1 8.1 General 8-1 8.2 Bedrock 8-1 8.3 Overburden 8-3 8.4 Seismicity 8-4 9.0 BRIDGE CREEK ALTERNATIVE 9-1 9.1 General 9-1 9.2 Stream flow synthesis 9-1 9.3 Water yield 9-3 9.4 Evaluation of Bridge Creek Reservoir 9-4 9.5 Topography and geology 9-4 9.6 Raising Bridge Creek Dam 9-5 9.7 New downstream high dam 9-6 10.0 TWITTER CREEK ALTERNATIVE 10-1 10.1 General 10-1 10.2 Stream flow synthesis 10-1 10.3 Water yield 10-5 10.4 Topography and geology 10-5 10.5 Preliminary project arrangement 10-6 11.0 FRITZ CREEK ALTERNATIVE 11-1 11.1 General 11-1 11.2 Stream flow synthesis 11-1 11.3 Water yield 11-5 11.4 Topography and geology 11-8 11.5 Preliminary project arrangement 11-9 12.0 COMPARISON OF FRITZ & TWITTER CREEKS 12-1 12.1 General 12-1 12.2 Twitter Creek Cost 12-1 12.3 Ftize Creek Cost 12-3 12.4 Alternate selection 12-3 13.0 FRITZ CREEK SITE ALTERNATIVES 13-1 13.1 General 13-1 13.2 Topography and geology 13-1 13.3 Alternate site 3 13-1 13.4 Alternate site 1 13-2 13.5 Alternate site 2 13-2 SECTION II PRELIMINARY DESIGN AND COST ESTIMATES Page 14.0 PRELIMINARY COST COMPARISONS OF ALL SOURCES 14-1 14.1 General 14-1 14.2 Ground water sources 14-1 14.3 Distant surface sources 14-2 14.4 Reverse osmosis 14-3 14.5 Bridge Creek 14-3 14.6 Twitter Creek 14-4 14.7 Fritz Creek 14-4 15.0 RESERVOIR SITE SELECTION 15-1 15.1 Basis of selection 15-1 15.2 Optimum reservoir size 15-2 15.3 Reservoir site selection 15-2 16.0 DESIGN FLOODS 16-1 16.1 Spillway design flood 16-1 16.2 Constructon design flood 16-2 17.0 PROJECT FEATURES 17-1 17.1 Basic preliminary design 17-1 17.2 Dam 17-1 17.3 Service spillway 17-2 17.4 Auxiliary spillway 17-2 17.5 Low level outlet works 17-2 17.6 Construction materials 17-3 18.0 INSTREAM ANALYSIS AND RESERVOIR SIZING 18-1 18.1 Discussion 18-1 18.2 Conclusions 18-2 18.3 Recommendations 18-3 19.0 WATER QUALITY 19-1 19.1 Objectives of water treatment 19-1 19.2 Quality of source of supply 19-1 20.0 WATER TREATMENT PLANT 20-1 20.1 General 20-1 20.2 Design criteria 20-1 20.3 Description of operation 20-3 20.4 Estimated power requirements 20-5 21.0 TRANSMISSION MAIN 21-1 21.1 Design 21-1 21.2 Location and siting 21-1 21.3 Materials 21-2 21.4 Depth of bury 21-2 21.5 Hydrants 21-3 SECTION III PROJECT FINANCING AND IMPACT ANALYSIS Page 22.0 COST ESTIMATES 22-1 22.1 General 22-1 22.2 Basis of costs 22-2 22.3 Construction cost estimates 22-3 23.0 PROJECT IMPLEMENTATION 23-1 23.1 Schedule 23-1 23.2 Proposed geotechnical investigations 23-1 24.0 CONCLUSIONS AND RECOMMENDATIONS 24-1 24.1 Conclusions 24-1 24.2 Recommendations 24-2 25.0 PROJECT ECONOMIC AND FINANCIAL ANALYSIS 25-1 25.1 General financing 25-1 25.2 Financing sources 25-4 25.3 Financing prospects 25-10 26.0 ENVIRONMENTAL ASSESSMENT 26-1 26.1 Introduction 26-1 26.2 Summary of proposed action 26-2 26.3 Existing conditions 26-6 26.4 Impacts & mitigation 26-12 26.5 Permits and regulations 26-15 SECTION IV PUBLIC PARTICIPATION 27.0 SUMMARY OF MEETINGS 27.1 Minutes of Fish & Game meeting, May 5, 1983 27.2 Notice of Public Workshop 27.3 Minutes of Public Workshop, September 13, 1983 27.4 Response to Public Workshop APPENDICES FIGURES GLOSSARY REFERENCES LIST OF TABLES Page 2.1 Average Daily Demand (ADD) by Month, MGD 2-2 2.2 Current & Projected Population, Homer Area 1978 to 2000 2-5 2.3 Estimated Future Average Daily Demands (ADD), MGD (Exclusive of Demand Outside City Limits) 2-7 2.4 Estimated Future Average Daily Demands (ADD), MGD (Including Population Outside City Limits) 2-8 2.5 Estimated Future Maximum Daily Demand (MDD), MGD (Exclusive of Demand Outside City Limits) 2-10 2.6 Estimated Future Maximum Daily Demand (MDD), MGD (Includes Population Served Outside City Limits) 2-11 3.1 Logs of Selected Wells in Homer Area 3-3 3.2 Water Analysis from Selected Surface and Ground-Water Sources 3-6 4.1 Selected Water Quality Characteristics China Poot Lake (Leisure Lake) 4-4 6.1 Precipitation and Temperature Data 6-3 6.2 Stream Flow Data 6-6 6.3 Estimated Mean Monthly Potential Evaporation 6-8 9.1 Simulated Stream Flow, Bridge Creek, cfs 9-2 10.1 Partial Record Data, Twitter Creek 10-2 10.2 Simulated Stream Flows, Twitter Creek, cfs 10-4 11.1 Partial Recoprd Data, Fritz Creek 11-2 11.2 Simulated Stream Flows, Fritz Creek, cfs 11-6 11.3 Effect of Instream Flow Requirement, Fritz Creek 11-7 12.1 Twitter & Fritz Creeks Reservoir Data 12-2 15.1 Project Costs at Different Sites 15-1 LIST OF TABLES (continued) Page 19.1 Source Water Quality - Color, Turbidity 19-3 19.2 Source Water Quality - Iron, Dissolved Solids 19-4 19.3 Source Water Quality - pH, Alkalinity 19-5 22.1 Cost Estimate 22-4 25.1 Existing & Projected Water Usage and Customers, 1983 to 2006 25-3 25.2 Projected Rate Impacts of Water Suppply Expansion Alternatives Assuming No Grand Financing 25-5 25.3 Projected Impacts of Water Supply Expansion Alternatives Assuming 90 Percent Grant Financing 25-6 26.1 Dam Construction - Materials Quantities in Cubic Yards. 26-5 26.2 Fritz Creek Water Appropriations 26-9 26.3 Dam Construction Materials 26-13 26.4 Summary of Permits & Certificates 26-16 LIST OF FIGURES I ~~~~~~~~~~~~~~~~~~~APPENDIX 1.1 Location Map 2.1 Average Daily Demand, MGD (Exclusive of Demand Outside City Limits 2.2 Average Daily Demand, MGFF (Includes Demand Outside of City Limits) 2.3 Maximum Day Demand, MGD (Exclusive of Demand Outside City Limits) 2.4 Maximum Day Demand (MGD (Includes Demand Outside City Limits) 3.1 Location of Wells and Springs 5.1 Process Flow Diagram - Seawater Reverse Osmosis Conversion 6.1 Mean Monthly Flow, Anchor River 6.2 Flow Duration Curve, Anchor River 9.1 Mean Monthly Flow, Bridge Creek 9.2 Bridge Creek Mass Curve 9.3 Bridge Creek Water Yield 9.4 Yield vs. Demand 9.5 Bridge Creek Cam 10.1 Monthly Flows, Anchor River & Twitter Creek 10.2 Discharge Measurements, Anchor River vs. Twitter Creek 10.3 Project Alternatives Fritz & Twitter Creek Dams 11.1 Discharge Measurements Firtz Creek vs. Anchor River 15.1 Optimum Size of Reservoir 15.2 Effects of Instream Flow on Yield and Reservoir Size 16.1 Flood Frequency Chart U ~~~~~~~~~LIST OF FIGURES (continued) 3 ~~~~17.1 Fritz Creek Dam Plan and Section 17.2 Fritz Creek Dam Sections and Details 20.1 Flow Diagram, Proposed Fritz Creek Water Treatment Plant 1 ~~~22.1 Project Costs vs. Reservoir Size 3 ~~~23.1 Project Schedule U U U I I SECTION I FUTURE WATER REQUIREMENTS I & SUPPLY ALTERNATIVES I I I I I I I I I I I I 1.0 INTRODUCTION 1.1 General N ~~~This Water Improvement Study for the City of Homer includes Preliminary 5 ~~~Engineering and Cost Estimate of a Storage Reservoir and Dam; Prelimi- nary Engineering and Cost of Storage, Treatment and Transmission Facilities; Environmental Assessment of the Preferred Alternative and 3 ~~~the Land Acquisition Analysis. 5 ~~~In order to design facilities it is necessary to determine the pro- jected water needs. This was done in the Draft 1982 Comprehensive Plan for the Distribution of Water by others. We reviewed the assumptions and projections for residential, commercial-industrial uses and system losses and found the figures to be reasonable. We therefore accepted the figures and incorporated them into this study. 1.2 Scope of Work N ~~~We have carried out the water supply study for the City of Homer by completing four major objectives. These objectives were developed and U ~ ~~are timed to occur based upon our understanding of the needs of the City and the extent to which reliable technical data are available. The result has been an analysis of future needs and availability, as well as development of a preliminary engineering design for a new 5 ~~~municipal water supply for the City. Finally, costs, project impacts, and alternative project financing has been evaluated and presented such that recommended improvements may be scheduled and budgeted by the Ci ty. 1-1 The four objectives are: OBJECTIVE 1: EVALUATE FUTURE WATER REQUIREMENTS AND WATER SUPPLY 5 ~~~~~~~ALTERNATI VES 3 ~~~OBJECTIVE 2: PREPARE PRELIMINARY DESIGN OF PREFERRED SUPPLY SOURCE AND ASSOCIATED SYSTEM IMPROVEMENTS * ~~~OBJECTIVE 3: PROJECT FINANCING AND IMPACT ASSESSMENT 5 ~~~OBJECTIVE 4: PUBLIC PARTICIPATION AND REPORT PREPARATION The timing of these objectives has been developed in accordance with the schedule for completion of the City's 1982 Comprehensive Plan and other related projects to be undertaken by the City. 1.3 Results of Study The results of the study include: - Analyses of water demands, future needs and alternative sources of supply; recommendations for development of preferred alternative supply I ~~~~- Analysis and development of design criteria for water reservoir, dam, water treatment, pumping, transmission and storage 5 ~~~~~improvements to existing City water system - Preliminary layout and design concepts for recommended system I ~ ~~~~improvements U ~~~~- Cost estimates for system improvement alternatives 1-2 - Environmental assessment of project development and mitigating * ~~~~~measures - Project feasibility and financing alternatives; evaluation of 3 ~~~~~impact of project on City financial structure 1 ~~~1.4 Study Source Locations * ~~~Locations of potential sources for additional water are shown on Figure 1.1. I~~~~~~~~~~~~~~- 2.0 WATER DEMAND 2.1 General 1 ~~~An estimate of future water demand for Homer is necessary in analyzing the timing and need for development of additional water supplies. 1 ~ ~~~Several previous studies have been conducted (USDA, 1962; Hill and Associates, 1971; CH2M-Hill, 1977; and CH2M-Hill, 1980) in which j ~~~projections were prepared and recommendations made regarding future water needs and possible supplies for the City. These studies primar- ily used growth in population as the basis on which water demands were projected because there was a lack of reliable long-term demand data to use for this purpose. With operation of the water treatment plant for the period 1976-82, however, more accurate demand data are available to utilize in projecting future water use within the City. 2.2 Exiting Demand Table 2.1 is a summary of water demands during the period 1976 through the first nine months of 1982 based upon total supply to the distribu- tion system. These records show total flow which has been supplied to the distribution system from the existing water treatment plant and U ~ ~~500,000 gallon storage tank at the plant- Since 1976, annual average demand has increased from 0.380 to 0.560 MGD, or at an average annual 3 ~~~rate of growth of 6.7 percent per year. Over the same period, popula- tion has increased from approximately 1,600 to 2,873 or at an annual growth rate of 10.2 percent according to the latest Borough census figures. During this period the number of residences served has been reported to have increased from approximately 200 (CH2M-Hill, 1977) to 700 (J. Hobbs, 1982). 2-1 TABLE 2.1 AVERAGE DAILY DEMAND (ADD) BY MONTH, MGD Month 1976 1977 1978 1979 1980 1981 1982 Jan. 0.320 0.275 0.627 0.390 0.555 0.496 0.650 Feb. .320 .233 .424 .420 .509 .436 .505 Mar. .398 .221 .364 .418 .481 .404 .469 Apr. .424 .256 .366 .401 .461 .498 .397 May - .253 .316 .464 .499 .405 .447 June - .318 .513 .528 .481 .514 .495 July .413 .381 .548 .722 .804 .790 .879 Aug. .546 .476 .444 .724 .714 .747 .779 Sept. .447 .367 .403 .559 .463 .533 .418 Oct. .337 .307 .371 .551 .593 .586 Nov. .265 .521 .515 .425 .516 .457 Dec. .325 .592 .479 .632 .555 .524 Annual Average 0.380 0.350 0.448 0.520 0.550 0.533 0.5601 1Based upon first nine months of record Source: Homer Water Treatment Plant Monthly Operating Reports, 1976-1982 2-2 Three factors tend to influence the proportion of total demand which is allocated to the various components such as residential, public, I ~ ~~commercial, large commercial, and miscellaneous demand. First, the greater proportion of the City's population now being served can result 3 ~~~in a greater proportion of total demand being attributable to the residential, public and commercial component. This is particularly * ~~~true if the other components remain at nearly the same level of demand with time. Second, changes in production and process variations or closures by the major water users in the large commercial component can I ~ ~~have a dramatic effect on water usage in that category. A good example of this is the closure of Campford Fisheries on Homer Spit and the 3 ~~~prospects for a reduced crab catch requiring processing by Seward Fisheries on the Spit. Third, the City's recent efforts in a leak 3 ~~~investigation program can result in the reduction of miscellaneous demand due to meter inaccuracies, leaks, etc. 1 ~~~In the 1977 Comprehensive Water Plan (CH2M-Hill, 1977), residential, public and commercial demand was reported to constitute 20 percent of 3 ~~~the average annual demand within the City, while the large commercial component made up over one-half the annual average daily water consump- 3 ~~~tion. Of the large commercial component, over 90 percent was reported to be attributable to the two processors on the Spit. Miscellaneous demand was reported to constitute 24 percent of total demand, which was greater than that normally in distribution systems (10 percent). With rapid population growth and changes in production by the processors on the Spit, however, the proportion of total demand by each component is likely to be different now than in 1976. As the Comprehensive Water 3 ~~~Plan is updated, the proportion of total demand currently attributable to the various components will be determined and estimates of usage * ~~~prepared that can be used to verify estimates provided herein. For purposes of this first report, it has been assumed that water use I ~ ~~in the large commercial category currently averages approximately 0.2 MGD (J. Hobbs, 1982), about 35 percent-of annual average demand, or at 3 ~~~~about the same level of demand as earlier reported (CH2M-Hill, 1977). 2-3 Because the City has recently performed leak investigations, it is assumed that miscellaneous demand (leakage, firefighting, hydrant I ~ ~~flushing, etc.) has remained at about the same level of demand, or about 0.1 MGD as earlier reported in the 1977 Comprehensive Water Plan, 5 ~~~even though the distribution system has been expanded since then and now conveys larger flows. The remainder of the total demand, approxi- mately 0.26 MG0, is therefore allocated to residential, public and commercial demand. Based upon 700 residential units being served with a population density of 3.2 persons per household unit, per capita water use in this category currently averages about 120 gallons per capita per day (gpcd). This compares well with per capita usage deter- mined in the 1977 Comprehensive Water Plan. It should be noted that the figure is subject to variation, however, as more of the City's 3 ~~~population acquires water services due to expansion of the existing distribution system. Nonetheless, per capita usage is a useful indi- cator in estimating future demands likely to occur in response to population growth. 1 ~~~2.2 Future Demand In Table 2.2, projected population of the City (Pacific Rim Planners & Engineers, 1982) and surrounding area for low, intermediate and high 3 ~~~rates of growth are given for the period 1985-2010. These population projections are described more fully in the Homer Comprehensive Plan update currently in preparation. Overall, the intermediate, or I ~ ~~mid-range, projections anticipate declining rate of growth in percent- age terms, but stable to increasing growth in absolute terms. The 3 ~~~growth rate is projected to fall from the current 9percent-plus rate to 7.5 percent through 1985, 6.5 percent through 1990 and 5.5 percent thereafter. Absolute population increases would rise from the recent rate of 175 additional persons per year to about 260 by the end of the 1980's, and nearly 300 per year during the 1990's. It is difficult to project with great confidence beyond more than a decade or so, since many developments which will affect total population cannot yet be I ~~~identified; however, projections for 1995 to 2010 based on existing 2-4 Table 2.2 CURRENT AND PROJECTED POPULATION HOMER AREA - 1978 to 2010 City Other Total of Homer Homer Areas* Homer Area Actual 1978 2,054 1,577 3,631 1980 2,209 NA NA 1981 2,588 NA NA 1982 2,873 2,069 4,942 Low Projection 1985 3,100 2,300 5,400 1990 3,900 3,000 6,900 1995 4,500 3,500 8,000 2000 5,200 4,200 92400 2005 5,800 4,2600 10,400 2010 6,400 5,100 11,500 Intermediate Projection 1985 3,400 2,800 6,200 1990 4,700 4,000 8,700 1995 6,200 5,600 11,800 2000 8,100 7,500 15,600 2005 9,400 8,800 18,200 2010 10,900 10,400 21,300 2015 12,000 11,500 23,500 2020 13,200 12,700 25,900 2025 13,900 13,300 27,200 2030 14,600 14,000 28,600 High Projection 1985 3,800 3,100 6,900 1900 6,500 5,600 12,100 1995 10,400 9,600 20,000 2000 13,300 12,600 25,900 2005 16,200 15,700 31,900 2010 19,700 19,600 39,300 2015 21,800 22,700 44,500 2020 24,100 25,100 49,200 2025 25,300 26,300 51,600 2030 26,600 27,600 54,200 *Diamond Ridge, Fritz Creek and Kachemak City voting precincts (1978 boundaries) NA - Data not available Source: Kenai Peninsula Borough 1979 and 1982, and Pacific Rim Planners & Engineers, Olympic Associates Company. 2-5 U ~~~growth factors anticipate increasing numbers of new residents, but * ~~~falling growth rates in percentage terms. These projections were prepared primarily by extrapolating previous population trends, but also considering possible economic development scenarios described in the Homer Comprehensive Plan (Pacific Rim Planners & Engineers, 1982). In essence, potential population growth is limited only by the capacity of possible economic activities in * ~~~Homer and nearby vicinities. In considering the intermediate growth scenario, increases in residen- I ~~~tial, public and commercial demand are expected to constitute the major growth in demand for water within the City. Annual average day demand projections occurring under this scenario are shown in Tables 2.3 and 2.4. Table 2.3 represents estimated demands from population growth within City limits, while in Table 2.4, estimated annual average day demands also include that portion of the population living outside the City that might require water service in the event that a Fritz Creek I ~~~reservoir is developed. Also shown in Tables 2.3 and 2.4 are estimated average daily demands that would be experienced under the higher rate * ~~~~of population growth in the City and surrounding area best served by a Fritz Creek reservoir. Figures 2.1 and 2.2 detail these projections * ~~~and provide a comparison with other recent estimates of future demands (CH2M-Hill, 1980). I ~~~In preparing these estimates, it is assumed that large commercial and miscellaneous demands remain at or near present levels, and that all * ~~~population growth taking place within the City limits over the period is serviced. One-half of the population growth in the Kachemak City and Fritz Creek precincts are assumed to be serviced, and water -requirements from these areas are envisioned to be only for residen- tial, public and commercial purposes. Large commercial demands are difficult to predict, and hence estimates are provided both with and without an increase in demand in that c-ategory. Higher rates of per I ~~~capita usage are assumed under the high growth rate scenario since 2-6 TABLE 2.3 ESTIMATED FUTURE AVERAGE DAILY DEMANDS (ADD), MGD (EXCLUSIVE OF DEMAND OUTSIDE CITY LIMITS) Condition 1985 1990 1995 2000 2005 2010 Intermediate Population Growth1 0.67 0.85 0.96 1.19 1.34 1.52 High Population Growth2 0.74 1.13 1.61 2.02 2.42 2.91 High Population Growth w/large commercial increase 0.84 1.23 1.71 2.12 2.52 3.01 assuming residental, public and commercial demand @ 120 gpcd, entire population served 2assuming same historical level of large commercial demand and misc. demand 3assuming residential, public & commercial demand @ 140 gpcd, entire population served 2-7 TABLE 2.4 ESTIMATED FUTURE AVERAGE DAILY DEMANDS (ADD), MGD (INCLUDING POPULATION OUTSIDE CITY LIMITS) Condition 1985 1990 1995 2000 2005 2010 Intermediate Population Growth1 0.80 1.04 1.23 1.55 1.76 2.03 High Population Growth2 0.89 1.40 2.07 2.64 3.18 3.87 High Population Growth w/large commercial increase2 0.99 1.50 2.17 2.74 3.28 3.97 assuming residental, public and commercial usage of 120 gpcd inside Homer, with entire population served, and demand of 150 gpcd outside City limits 2assuming 50% of projected population growth in Kachemak City and Fritz Creek precincts served 3assuming residential, public & commercial usage of 140 gpcd inside Homer, with entire population served, and demand of 150 gpcd outside City limits 2-8 I ~~~economic projections (Pacific Rim Planners & Engineers, 1982) suggest that Homer's economy might rely increasingly more on tourism and I ~~~visitor services, in which non-resident use would possibly result in an apparent greater per capita residential usage. However, the estimates * ~~~~serve to define the range in which future use is likely to occur. Maximum day demands are also detailed in Tables 2.5and 2.6, and illustrated in Figures 2.3 and 2.4. Projections are developed which indicate a range of demands depending upon population growth and potential for increases in large commercial demands. I~~~~~~~~~~~~~~- TABLE 2.5 ESTIMATED FUTURE MAXIMUM DAY DEMAND (MDD), MGD (EXCLUSIVE OF DEMAND OUTSIDE CITY LIMITS) Condition 1985 1990 1995 2000 2005 2010 Intermediate Population Growth1 1.52 1.88 2.10 2.56 2.86 3.22 High Pypulation Growth 1.66 2.44 3.40 4.22 5.02 6.00 High Population Growth , w/large commercial increase 1.96 2.74 3.70 4.52 5.32 6.30 assuming ratio of maximum day demand to average day = 2.0, entire population served 2assuming large commercial peak day demand of .3 MGD 2-10 TABLE 2.6 ESTIMATED FUTURE MAXIMUM DAY DEMAND (MDD), MGD (INCLUDES POPULATION SERVED OUTSIDE CITY LIMITS) Condition 1985 1990 1995 2000 2005 2010 Intermediate Population Growthl 1.79 2.26 2.64 3.28 3.70 4.24 High Pypulation Growth 1.96 2.98 4.32 5.46 6.54 7.92 High Pypulation Growth , w/large commercial increase 2.26 3.28 4.62 5.76 6.84 8.22 assuming ratio of maximum day demand to average day = 2.0, entire City population served, 50% of population in Kachemak City and Fritz Creek precincts served 2assuming large commercial peak day demand of 0.3 MGD 2-11 3.0 ASSESSMENT OF GROUNDWATER SUPPLIES U ~~~3.1 Background I ~~~As an alternative to surface water development, conjunctive use of groundwater in the Homer area with existing supplies is herein con- sidered. Previous studies (Feulner, A.J., 1963; Waller, R.M., Feulner, A.J.., and Morris, D.A., 1968) suggest that some form of conjunctive use might prove advantageous, although such studies were conducted when the area's population and water demands were significantly less than current totals. At one time, the City did practice this method of I ~ ~~operation, when six wells were drilled in the Bridge Creek drainage near a small surface reservoir. This practice was discontinued, how- I ~~~ever, as several of the wells developed operating problems such as casing misalignment, declining production, etc., (Hill and Associates, 3 ~~~~1971) and the existing reservoir was constructed. Currently, indi- vidual wells and springs supply water for primarily domestic purposes 3 ~~~for a significant portion of the area's population,-such wells being located in both the bench and upland portions of Homer and the sur- * ~~~~rounding area. 3.2 Occurrence of Groundwater Fresh groundwater occurs in two zones within the study area: first, in 3 ~~~the young, thin, unconsolidated Quaternary deposits located along the bench and lowland portions of Homer, as well as stream beds and valleys nearby; and second, in the escarpment region above and to the north of the City limits (See Figure 3.1). This second region, referred to as the Kenai Formation, consists of moderately indurated sand, silt, and I ~~~clay of Tertiary age generally in thin beds and lenses, interbedded 3-1 with a few thick lenses of fine conglomerate and many thin lenses of subbituminous coal (Waller, R.M., Feulner, A.J., and Morris, D.A., 1968). The thickness of the formation is not known, although test drilling near Homer has been conducted in which over 10,000 feet of the Formation has been discovered. Typical logs from wells drilled in the Formation are shown in Table 3.1. Underlying the entire Homer area, the Kenai Formation contains many fine grained sandstone sequences containing ferruginous masses or ironstone concretions in bands or as scattered nodules throughout the formation (Waller, R.M., Feulner, A.J., and Morris, D.A., 1968). The formation dips shallowly to the north such that groundwater movement is thought (Hill and Associates, 1971) to flow to the north parallel to the dip and away from the City. Permeability is generally poor (Hill and Associates, 1971). Groundwater in these two water-bearing strata is derived from rainfall and snowmelt, which, as previously mentioned, averages about 23 inches at the airport and 28 inches on the upland above the escarpment at altitudes in excess of 1,000 feet. Of this annual precipitation, total recharge to the area is only about 5 inches per year (238,000 gpd/mi2) or about one-fifth of total annual precipitation (Hill and Associates, 1971). This compares favorably with recharge rates for aquifers of similar geologic and climatic conditions (Walton, W.C., 1970). Groundwater in the Homer area is of the sodium bicarbonate or calcium bicarbonate type, and in some areas contains as much as 30 ppm iron and some combustible gas (Waller, R.M., Feulner, A.J., and Morris, D.A.; Fromer, 1982). Selected chemical analysis shows groundwater to con- tain moderate amounts of dissolved solids, and can range from extremely soft to very hard. The soft water is generally found in the Kenai Formation, the harder water from the Quaternary deposits in the lowland areas. The pH of the water is typically in the range of 6.7 to 8.5, suitable for most purposes. Sulfides have been reported to be present 3-2 TABLE 3.1 LOGS OF SELECTED WELLS IN HOMER AREA, ALASKA WELL 2 @ OHLSON MOUNTAIN 'Drilled in 1960 by Corps of Engineers, U. S. Army, Alaska District. Diameter 6-inch to 398 feet, 5-inch to 531 feet, cased 6-inch to 398, 5-inch liner set from 381 to 531 feet, perforations cut with a torch, approximately 1/16-inch wide -and 6-inch long, perforated 423-470, 504-508, 513-521, and 529-531][ Material Thickness Depth (feet) (feet) Backfill 1 ................. 2 2 Yellow clay ..... .......... 14 16 Blue clay ...... . ......... 12 23 Coal seam ................ 1 29 Sandy silt (fine) ............. 24 53 Brown shale ............ 15 68 Brown sand and silt (fine) ........ 16 84 Brown shale with coal seams (water at about 2 gpm) .............. 3 87 Brown shale .. 22 109 Brown shale and shell rock ....... . 3 112 Coal with rock lenses ........... 5 117 Grey shale ........ . ...-. 27 144 Coal (dry) . . .............. 2 146 Grey shale . . .............. 30 176 Sandstone, fine ............. 40 216 Brown shale with thin lenses of coal . 4 220 Grey shale ................ 19 239 Brown shale ............... 55 294 Grey shale, sandy .. 12 306 Grey sandstone .............. 21 327 Coal (water level in well dropped from 81 to 181 feet) .......... 10 337 Brown shale ................ 34 371 Coal .. 3 374 Brown shale. 12 386 Brown shale, sandy ......... . . . 8 394 Coal ... 4 398 Blue shale . 62 460 Brown shale with coal seams . . . . . . 10 470 Brown shale, sandy ............. l0 480 Brown shale ................ 7 487 Coal ................... 1 488 Brown shale ........... . . . 4 492 Coal ................... 7 499 Brown shale ............... 4 503 Coal ................... 3 506 Brown shale ................ 2 508 Coal ............... 3 511 Brown shale, sandy ............ 3 514 Grey sandstone (hard) ........... 17 531 Remarks: Static water level 220 feet. 3-3 TABLE 3.]I (CONT'D) LOGS OF SELECTED WELLS IN HOMER AREA, ALASKA Material Thickness Depth (feet) (feet) Well 90. U. S. Air Force (White Alice site). Log by Chapman Vegetation ...... . ... . 2 2 Surface soil .............. 23 25 Clay .................. 7 32 Clay with rock ............. 15 47 Clay changing to claystone ....... 3 50 Claystone ................. 2 52 Hardstone ............. 23 75 Coal, soft (small amount of water... 3 78 Sandstone, hard ............. 5 83 Coal and stone, mixed .......... 4 87 Sandstone ................ 26 113 Clay, soft ............. . . 8 121 Sandstone .............. 9 130 Clay, very soft : ............ 7 137 Coal, soft ............... 5 142 Sandstone .............. 7 149 Clay, fairly hard ....13 162 Sandstone .......... ..... 4 166 Clay ...... 28 194 Coal and rock ............. 3 197 Clay . .................. 27 224 Stone and coal, wi.th clay, mixed . . . 7 231 Clay .................. 7 238 Siltstone, very hard . . . .... 8 246 Clay ......... 12 258 Clay, very soft and sticky ....... 2 260 Clay, softer and squeezing ....... 10 270 Clay .................. 10 280 Clay, soft and blue silt ........ 40 320 Coal, very hard and brittle ...... 5 325 Claystone, hard and shale ....... 53 378 Sandstone (water) . . . ......... 36 414 Claystone ............... 1 415 Clay, soft and squeezing ........ 35 450 Source: Feulner, A.J., 1963; Waller, R.M., 1963 3-4 (Fromer, 1982), as well as insignificant concentrations of fluoride. Table 3.2 details selected chemical characteristics of groundwater from wells located throughout the region. 3.3 Use of Groundwater In general, the water from the Kenai Formation in the uplands above and to the north of the escarpment is of better quality than that from Quaternary deposits below. Iron concentrations average only 1-2 ppm (Waller, R.M., Feulner, A.J., and Morris, D.A.) as contrasted to about 4 ppm in the lowlands, stream valleys and bench areas. The water, also being lower in dissolved solids and being softer, would probably require less extensive treatment prior to use. Of the two water-bearing strata, the Kenai Formation is also reported (Feulner, A.J., 1963; Waller, R.M., Feulner, A.J., and Morris, D.A., 1968; Hill and Associates, 1971) to constitute the most extensive and most productive aquifer system in the study area. Well logs and pro- duction records from several wells drilled in the area (Waller, R.M., 1963) suggest that water may be obtained at or near each of the coal seams penetrated by wells, although the yield from each of the seams penetrated is low (on the order of 2-5 gpm per seam). Lesser quanti- ties of water are reported to be available from the unconsolidated alluvial and flood-plain deposits occurring along stream channels and in the lowlands. The USGS has predicted yields from properly constructed and operated wells in the area based upon results of test drillings and review of operating records (Waller, R.M., Feulner, A.J., and Morris, D.A., 1968). Data suggest sustained annual yields in properly spaced and constructed wells in the Kenai Formation upland of Homer between 50 to 80 gpm (.072-.115 MGD), which compares favorably with reported yields (Hill and Associates, 1971) from wells previously pumped in the Bridge Creek area for municipal purposes. Lower yields of between 10-20 gpm might be obtainable in the bench area, while yields from shallow wells 3-5 TABLE 3.2 WATER ANALYSES FROM SELECTED SURFACE AND GROUND-W1ATER SOURCES (Analyses by the U.S. Geological Survey -chemical concentrations in parts per million) "Mt.etton. Wel Da e PvptI of sic Twiat mangs W- *S2' Pa" 1IC It chtiaief or. SR." MyIe m CO andd::for 9lnt tebOn Jron IRA m Clam sium 11na0, Ua Chiud We4' . ~ am 20 IZ. (ow. CalCIl ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~MI CO Inao cron 91's cim C) I I allu~~~~~~~~~~e, sauna~111dim no 'at In feet I lima (Co (mg ) 43.7 6 2 I . I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ wzo man-Cro.a 1,C 16~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~6 7.03' .33 . 310 to h~.5 31 .2 g o 97as6 lb N16NESE It., 6-16.5b 36 a) i 64 3 4.9 40 2.9 3A7 4 .0 .4 246 3 . 0 SESESW 11 -.4 7 4 64 8.13 146 I - 3 16 NE,.WS% '1 o-24-00 110 23 13. .00 2.4 I10 4' 10 'h 3. 6 6 .3 7 13i. I'it,~o s 12 SENW&NEI 14)12-14-621 187 J17 7' 0 . .0 80 J4.0 1.0'. 1 .2 .6 14 .I b 20SE1NWNW 84' 41-831_3~ 111 is- 4 I is44 1NESWNW 49b . 4- 4.60 73 40 I1 .6 2 4.2 8.0 1.21 14 .0 � .2 .0 1.4 W203 6.7 0 '1-33-63' 2.i7 -j. .80 42 17 ~~~ ~~~~~~~~~~~2( 4.3 231'. 316 .0 .3 26-34 43(1 6.6 4.14W 29wswsw 84', i-2 Al. 4923.0 .1 13 70 I64 I3 . 6.0 .3 OA. 114 24-, V 21 SWNWSE *1141 Al -to. 432 33114'I I 1. 1~ 7-.2 27o 60 VS K * 17.0 2 6 3 NN A 32 6i- 3-Et. ZL 4 7 2.t,' - I14 Ito 1.1 I C. Ito 1 4 64 6-i 03 4I" 6.9 , :Crteek Ci&I 3. .0 7.2 -'.6 21' 60 S. .0 . .2 M 2 .1~~~~~~~~~~~~~~~~~~~~~~~~~~~# . in alluvial-fan deposits near Beluga Lake are estimated to yield up to 25 gpm. Wells on the Spit are reported to yield only saline or brack- ish water. Local well drillers report that yields in excess of 80 gpm are possible from deep wells drilled in the Kenai formation, but that casing, screening and development of such wells are necessary and I ~~~depths may be excessive. The above data suggests that groundwater would probably not provide an 3 ~~~economic source of supply to augment the Bridge Creek reservoir. Low yields from individual wells in the Kenai Formation would necessitate installation of many wells to supply sufficient quantities of water to the municipal system to match demand in excess of 1.7 MGD, the reported capacity of the existing reservoir. Alternatively, fewer but deeper I ~~~wells might be drilled and developed, but with associated pipeline, power and treatment costs required of such extensive groundwater 3 ~~~development, it is likely that such development would be uneconomic. I~~~~~~~~~~~~~~- 4.0 ASSESSMENT OF DISTANT SURFACE WATER SUPPLIES 5 ~~~4.1 Sources of Supply I ~~~USGS maps of the area across Kachemak Bay from Homer show several lakes and streams that might be suitable for use. In evaluating the possible sources, attempts were made to locate earlier studies which were reported (L. Farnen, 1982) to have been prepared addressing the use of Hazel Lake such that this source could be studied further. Efforts to locate such studies were unsuccessful, however, as interviews with City staff and other consultants familiar with Homer's water system could not produce an identifiable project in which use of Hazel Lake was addressed. As a result, attention has been focused on evaluating several possible sources located on the south side of the Bay and identifying factors associated with their use. Inspection of the area immediately across from the Spit shows that many 5 ~~~of the surface streams draining into Kachemak Bay are glacial in origin, and likely would not be of suitable water quality for municipal purposes. The area located across from the end of the Spit, the clos- est point to which connection to the existing distribution system is possible, is primarily land within Kachemak Bay State Park. Within the 5 ~~~Park boundaries, land and water use is reported to be for public recreation and enhancement only (R. Crenshaw, 1982), which suggests * ~~~that use of surface waters for municipal water supply would require negotiation with the State Department of Natural Resources to secure 5 ~~~~their use. Surface sources not within the boundaries of the Park are several miles I ~~~distant from any point within Homer's water distribution system, 1 ~~~~~~~~~~~~~4-1 I ~~~however, and would require very long transmission lines, both under- water adoverland. The one body of water in this category that was I ~ ~~considered was Bradley Lake lying southeast of the head of Kachemak Bay. Attention was focused on Bradley Lake because of recent specula- tion of the lake being a potential hydroelectric site. It was felt that if a dam and power-generating facility were constructed, that incorporation of a water intake structure could be included. The hydroelectric potential has since been shelved. The cost of a remote intake structure, access road, four miles of underwater, and 20+ miles of overland transmission main would be prohibitive in cost; therefore this consideration was dropped. Attention has been directed towards China Poot Lake (Leisure Lake), a 3 ~~~relatively large and accessible source of water which appears to be the minimum distance from a connection with the existing distribution 3 ~~~system on the Spit, although its watershed lies within the State Park boundaries. 1 ~~~4.2 Utilization of China Poot Lake 3 ~~~~China Poot Lake is located about 0.7 miles upstream of the head end of China Poot Bay, or about 8 miles from the end of Homer Spit. Data 3 ~~~collected by the Alaska Department of Fish & Game concerning character- istics of the lake include the following (Alaska Department of Fish & 3 ~~~~Game, 1982): Parameter Value I ~~~~~~~Altitude 190 ft. Surface Area 0.42 mi2 Volume 8.5 x 108 ft3 (6.3 x 109 gal) Average Depth 72 ft. Maximum Depth 482 ft. Mean Discharge 87 cfs (from lake outlet) 4-2 Selected water quality characteristics obtained from the Department of Fish & Game are also shown in Table 4.1. The lake is oligotrophic and water quality is reported to be good and only slightly variable with time. From a water supply standpoint, the data in Table 4.1 suggest that the water would be a good source for municipal purposes, although additional data are necessary to predict specific treatment measures 3 ~~~needed to be employed. Nonetheless, comparison of these data to that collected for surface sources near Homer suggest a higher quality water I ~~~that would require less treatment than Twitter or Fritz Creeks. China Poot Lake lies within the boundaries of the Kachemak Bay State Park. The Departments of Natural Resources and Fish & Game were con- tacted to ascertain mechanisms by which water could be utilized for 3 ~~~municipal-purposes. Although the Master Park Plan has yet to be drafted, statutes which were developed when the State Park was created appear to limit use of lands and waters within the Park for public recreation and enhancement purposes, as mentioned earlier. Because of this, use of waters and land other than for recreation would require a special use be designated for the City and likely impose particular requirements on such a project to protect Park lands. Also, the Lake 5 *~~~is currently used by the Department of Fish & Game for a juvenile sockeye salmon stocking program, which supports the commercial sockeye 3 ~~~fishery within Kachemak Bay. In order to protect the stocking program in the Lake, effects on lake water levels and/or streamflow would need 3 ~~~~to be minimized. Because of these factors, it is assumed that utilization of water from I ~~~this lake would involve construction of a lake "tap" or intake and regulating structure, transmission line both underwater and overland, 3 ~~~and upgrading to the existing distribution system on the Spit. In addition, such a project would likely require a treatment facility to be constructed, preferably on the end of the Spit to provide at the minimum disinfection of supplies. (Bated upon the data presented in Table 3.1, it would also be necess ary to provide filtration as well.) A transmission line from the end of the Spit to convey the flow to the 4-3 TABLE 4.1 SELECTED WATER QUALITY CHARACTERISTICS CHINA POOT LAKE (LEISURE LAKE) Parameter Value (mg/l unless noted) Alkalinity 29-34 mg/l as CaCO3 pH 6.9-7.7 (avg. 7.2) Ca2+ 10-12 Mg2+ 2 Fe 12-25 g/l Suspended Solids 5 mg/l Conductivity 75-85 mhos/cm Color negligible Source: Alaska Department of Fish & Game, J. Koenings, 1982. 4-4 remainder of the City would require a larger capacity than the existing * ~~~~Spit pipeline. In considering this scenario, major costs would involve the construc- I ~~~tion of a transmission line from the lake to the Spit, a distance of approximately 8 miles. Of the 8 miles, a maximum of 3 miles might be 3 ~~~overland, depending upon alignment of the transmission line and loca- tion of the intake. The remainder would be a submerged pipeline cross- ing of Kachemak Bay and a portion of China Poot Bay. Pipe material used would need to be pre-tensioned concrete cylinder pipe with a steel outer shell, and mortar lined inside and out to provide negative buoy- I ~ ~~ancy. Since detailed information on bottom conditions and topography in the Bay is not available at this time, the type of excavation and 3 ~~~quantities can only be estimated. Since cost of such a transmission line is particularly sensitive to the bottom profile and sizing is not 3 ~~~complete, only order-of-magnitude costs can be developed at this time. Based upon similar projects, it is anticipated that installed costs for I ~ ~~the submerged portion of the transmission line would be on the order of $425 per foot, or approximately $11,220,000 (1982 dollars) for a 5-mile I ~~~~line. In addition, a three-mile overland portion of the transmission line could add as much as $4,118,000. The cost of 20,000 feet of main 3 ~~~~installed the length of the Spit has already been estimated at $5,206,000. An intake structure designed to preclude entry of fish would cost an estimated $500,000. Finally, a water treatment facility would cost approximately $1,500,000. Thus the total estimated cost without any land acquisition, easements or Department of Natural I ~~~Resources leases would conservatively be $22,544,000. Should capital cost estimates of the other alternatives be projected to be signifi- 3 ~~~~cantly greater as more detailed analysis is completed, however, further analysis of this alternative may be warranted. 4-5 5.0 ASSESSMENT OF REVERSE OSMOSIS FEASIBILITY 5.1 Background A ~~~Seawater reverse osmosis (RO) is moving into the large-production class in only about a decade following its commercial introduction. Already, I ~ ~~RO technology has been developed to the point where major metropolitan areas, such as Riyadh, Saudi Arabia, employ the technology to provide municipal supplies of potable water (DuPont Corp., 1981). With increasing energy costs and greater demands for fresh water, RO has 5 ~~~replaced multi-stage flash distillation as the preferred method of seawater conversion as RO represents the most energy-efficient technol- ogy developed to date. For brackish water also, RO is becoming more widely employed as an alternative to more conventional treatment methods or development of distant surface and/or groundwater supplies. In Homer, the apparent lack of adequate groundwater supplies and rela- 3 ~~~tively long distances to suitable surface sources suggests the need to investigate seawater utilization potential. With the City bordering on Kachemak Bay, abundant supplies of seawater could be used as a source to supply industrial, commercial and even residential demands in the area. In addition, having a large proportion of the City's water demand related to activities on the Homer Spit, use of RD technology on the Spit would allow demand to be met with a nearby water source. For these reasons, the feasibility of employing RD technology in Homer 3 ~~~is briefly reviewed herein. The type of technology to be employed and order-of-magnitude costs for installation of an RD system to meet a ~~~anticipated demands is included, and'conclusions drawn as to its applicability. This review is intended to allow comparison between this and other alternatives available to the City. 5.2 RO Technology Reverse osmosis is nothing more than sophisticated filtration. Water * ~~~is passed through a membrane under a pressure which is greater than the osmotic pressure of the dissolved salts in the water (Am. City & 5 ~~~County, 1978). The membrane separates the solution into two parts-- one dilute (permeate) and the other a concentrate (reject). In water treatment, the permeate is the desired product. RO membranes are I ~ ~~essentially non-porous and permit separation of solutes from water by differential solubilities and diffusion rates through the membrane. In 3 ~~~the main there are two cost-effective membrane materials: one based on cellulose acetate, the other on aromatic polyamide material (World Water, 1979). The geometry in which the membrane is packaged to form the permeator is important to successful conversion of seawater. The * ~~~membranes are either referred to as spiral wound or hollow fiber. In an RO plant, seawater is typically collected via seawells or in the I ~~~case of brackish groundwater, from wells experiencing salt-water intru- sion. From the well, the water is pretreated by a combination of 3 . ~~~physical and chemical means to protect the membranes which separate dissolved salts from the water. Usually, this pretreatment involves 5 ~~~~acid addition, sequestrant addition (chemical addition to stabilize scale-forming constituents in the water) and filtration through either sand or carbon filters. Following pretreatment, the water is pressur- U ~ ~~~ized by means of high-pressure pumps and fed to a bank of RO membranes which provide two effluent streams, the first being a concentrated 3 ~~~~reject stream of dissolved salts, and the second a product stream of high quality (low dissolved salts). The reject stream is wasted, and 3 ~~~the product passes to a storage tank for final processing. From this point, the water is degassified to remove carbon dioxide and hydrogen 1 ~~~~sulfide, and the pH adjusted to approxImately 7 prior to storage and 5-2 I ~~~distribution. A simplified flow diagram (Figure 6.1) of a typical 1 ~~~~seawater RO installation illustrates the process. 5.3 Application of RO Technology to Homer The process shown in Figure 5.1 is the type of system which would most * ~~~~likely be employed in Homer to augment fresh-water supplies from the existing reservoir. An advantage of this kind of process is that it is modular and can be constructed in phases to match demand for the product. In this manner, modules of a specific capacity can be con- structed sequentially in a plant designed for an ultimate capacity of up to several million gallons per day and construction phases staged over a long period of time. The particular installation schematically 3 ~~~represented by Figure 5.1 currently supplies approximately 3 MGD of potable water to residents of Key West, Florida, where alternative 3 ~~~fresh-water supplies must be piped more than 120 miles to augment the desalinated water. In a likewise fashion, an RO unit designed to convert seawater from Kachemak Bay to a potable supply could be located such that an alternative consisting of construction of a pipeline of several miles length, a surface water impoundment and associated treat- I ment ~~facilities would not be necessary. Because RO treatment of saline waters is energy intensive, however, and also less efficient at low 3 - ~~water temperatures, cost comparisons need to be made with other alter- natives at this stage. For an RO plant of the type illustrated in Figure 5.1, recent capital cost projections (DuPont Corp., 1981; World Water, 1979; Quinn, R.M., I ~ ~~~1982) suggest an installed equipment cost of between $4.00-$7.00 per gallon per day of plant product capacity for plants up to I MGD produc- tion. Above I MGD, plant costs (DuPont Corp., 1981) decrease somewhat due to economies of scale in plant construction. In Alaska, such 3 ~~~~plants would experience higher capital costs due to provisions to con- struct and operate a facility in sub-arctic conditions. For a plant 5 ~~~~constructed in phases in accordance'with demands at Homer, such as with 5-3 an initial capacity of 1.5 MGD to be increased later to 3 MGD, esti- mated initial capital costs (in 1982 dollars) would be on the order of $13,000,000-$18,000,000. This assumes that the initial treatment plant cost includes additional treatment capacity provided to offset reduced operating efficiency of permeators with low seawater feed temperatures. Further plant expansion to meet additional demands would likely cost an additional $2.00-$4.00/gpd of capacity. Comparison of these capital cost estimates with those suggested for a Fritz Creek alternative (CH2M-Hill, 1980) providing for fish flows suggests that RO would be more than double the cost of developing the Fritz Creek site. Because of its energy intensive nature, the operating costs of an RO plant would be much higher than that of a surface water plant of equal capacity. Typical operating costs for an RO plant producing approxi- mately i MGD are reported (DuPont Corp., 1981; Quinn, R.M., 1982) to be on the order of $4.00/1000 gallons of product, or approximately $1,400,000 per year for Homer. At a greater plant capacity, unit costs will decline only slightly, so an assumption of $4.00/1000 gal of product appears reasonable. Compared'to costs for operation and main- tenance of a Fritz Creek alternative assumed to be roughly equal to that incurred in operation of the Bridge Creek facility, RO appears to be much more expensive to operate and maintain. 5.4 Conclusions The utilization of RO technology to provide a municipal water supply for Homer, while technically feasible, appears to be economically unjustifiable in comparison with projected costs for alternative surface water development. Both capital and operating costs for an RO plant capable of supplying Homer with water to supplement Bridge Creek supplies are much in excess of those likely to be incurred in develop- ment and operation of a Fritz Creek supply. Further investigation of this source of supply is not warranted at this time unless all other sources of supply are found to be unfeasible. 5-4 1 ~~~~~~~~~~6.0 HYDROLOGY 1 ~~~6.1 General I ~~~Hydrological studies were performed on the existing Bridge Creek site and the proposed sites on Fritz and Twitter Creeks. This investigation was based on existing and in-house computer generated data. j ~~~6.2 Methodology 3 ~~~No long-term streamflow records suitable for reservoir design are available at the existing or potential dam sites. However, relatively good meteorological data are available in the vicinity of the study areas, and continuous streamf low data are available for approximately ten years from the nearby Anchor River. The approach adopted for the hydrologic aspects of the study was to 3 ~~~~reconstruct the historic streamf low record at the dam sites for a period of about twenty years. This data was then used to determine the 3 ~~~~yield at the sites under investigation. The historic streamflow record was reconstructed using computer based I ~~~mathematical models of the land surface hydrology. The models used were the National Weather Service's (NWS) Snow Accumulation and 5 ~~~Ablation Model and the NWS Soil Moisture Accounting Model. Together these models transform historic precipitation and temperature data. I ~~~~The process of snow accumulation and melt is modeled, as is movement of moisture either from rainfall or snowmelt, through the soil horizon I ~~~~into the stream channel system. 6-1 Having reconstructed the historic streamflow record, conventional mass curve analyses were used to estimate the reservoir capacities and yields. 1 ~~~6.3 Precipitation and Temperature Data if ~~~Daily precipitation data and daily maximum and minimum temperature data have been collected by the National Weather Service at four sites in the vicinity of Homer. The locations of these sites are shown in Figure 1.1 and information pertaining to the records is given in Table 2.1. The record available from Homer 8NW is too short to be of interest for j ~~~this study. The record from Homer Research Center is also of limited value because of the short length of record and the large amount of I ~~~~missing or estimated data. However, because of the proximity of Homer Research Center to the Fritz I ~ ~~Creek catchment, monthly precipitation data from this site were obtained for analysis. The records from Homer WSO and Homer 5NW are both of good quality with 3 - ~~very little missing or estimated data, and are the most useful data series for this study. The daily data from Homer WSO and Homer 5NW were obtained on magnetic tape from the National Climatic Center for the period January 1948 through December 1976. I ~~~The mean annual precipitation at Homer 5NW (elevation 1000 ft.) is 27.7 inches and the mean annual precipitation at Homer WSO (elevation 63 R ~~~ft.) is 23.2 inches. The mean monthly precipitation and mean monthly temperature at Homer WSO and Homer 5 NW are shown in Figures 2-1 and 5 ~~~2-3 for the common period of record October 1952 through September 1972. It is noted that this period represents water years 1953 through 3 ~~~~1972, i.e., twenty water years of data.- 6-2 m -~ - m - m m - mmm m-m Table 6.1 PRECIPITATION AND TEMPERATURE DATA Station Station Period of Mean Water-Year Mean Water-Year Station Name Index No. Elevation (ft) Record Precipitation (in.)* Temperature (OF)* Homer WSO AP 503665 63 Jan. 1943 - 23.2 36.3 present Homer 5NW 503670 1000 Mar. 1952 - 27.7 36.0 Aug. 1973 Homer 8NW 503672 1000 Oct. 1977 - present Homer Research 503680 280 Oct. 1973 - Center Dec. 1978 *Based on common period of record 1953-1972 The records indicate that the higher elevation land immediately north of Homer receives about 20% more precipitation than is recorded at the Homer WSO gage at Homer Airport. Close inspection of temperature data at Homer WSO also shows that this low elevation station experiences I ~~~occasional periods with appreciably lower temperatures than are encountered at Homer 5NW. These low temperatures are caused by cold air draining from glaciers on the north slopes of the Kenai Mountains and settling over Kachemak Bay. The temperature and precipitation record at Homer 5NW is thus more representative of conditions over the catchments of interest in this study than is the data from Homer WSO. I ~~~As mentioned earlier, monthly precipitation data were obtained from Homer Research Center for the period October 1973 through December 1978. During this period, National Weather Service records show that 8 months of data were missing, and data for parts of at least 4 months 3 ~~~were estimated. The methods by which these data were estimated have not been determined. Complete data for two years, 1974 and 1976 are available. The mean annual precipitation for this period is 17.48 I ~ ~~~inches at Homer Research Center and 22.61 inches at Homer WSO. Analysis of concurrent monthly data from Homer WSO and Homer Research 3 *~~~Center shows that the monthly data have a correlation coefficient of about 0.86. There is no obvious seasonal variation in the relationship 3 ~~~~between monthly precipitation data at the two stations. The short record available from Homer Research Center suggets that I ~ ~~~precipitation decreases as, one moves along the coast in a northeasterly direction from Homer. The long-term mean annual precipitation at Homer I ~~~Research Center is estimated as about 18.6 inches, i.e., 80% of the amount at Homer WSO. Similar reductions in precipitation may be 5 ~~~expected at the higher elevation as one moves in an easterly direction from Homer 5NW. 6-4 6.4 Streamflow Data I ~~~Streamfiow data in various forms have been collected by the U.S. Geological Survey from a number of sites of interest to this study. 1 ~~~The locations of streamflow gaging sites are shown in Figure 1-1 and information pertaining to the records available is given in Table 6.2. The continuous discharge record for the Anchor River near Anchor Point was obtained on magnetic tape from the U.S.G.S. Data from other sites have been obtained from the series of annual U.S.G.S. publications entitled, "Water Resources Data for Alaska." At the partial record 5 ~~~stations a number of discharge measurements are made each year, often during base flow conditions. The crest-stage data from Fritz Creek 3 ~~~gives the instantaneous peak flow observed in each water year. The quality of the continuous discharge record on Anchor River and I ~ ~~Twitter Creek is described by the U.S.G.S. as being either fair or good except during the winter months. Because of freeze-up, gage height I ~ ~~data is usually unavailable during the winter months November through April, and a continuous record is estimated by interpolating between -occasional instantaneous discharge measurements. These data are thus often of poor quality during the winter months. The partial record and crest-stage data probably provide accurate estimates of instantaneous flow rates at all times. I ~~~The mean annual flow at the Anchor River gage for the period of record is 208 cfs (1.56 cfs/sq. mi.). The drainage areas is 133 sq. mi. The 3 ~~~distribution of flows within the year is shown in Figure 6.1. The plot of mean monthly flows exhibits two peaks, one in May associated with 1 ~~~snowmelt and a secondary peak in October associated with early fall storms. Precipitation from November through March is generally in the form of snow. Freeze-up in the winter months results in low streamf lows from December through March. 6-5 Table 6.2 STREAMFLOW DATA Station Drainage Period of Type of Mean Annual Station Name Index No. Area (mi2) Record Record Runoff (cfs/mi2) Anchor River 15239900 133 June 1965 - Continuous 1.56 Sept. 1973 Record (water years 1966-73 & 1978-81) Sept. 1978 - 1.33 present (water years 1972-73) , Twitter Creek 15239845 1.63 1978 - present Continuous nr. Lookout Record Mountain Twitter Creek 15239880 16.1 Aug. 1971 - Continuous 1.32 nr. Homer Sept. 1973 Record (water years 1972-73) Fritz Creek 15239500 10.4 1963 - present Partial Record and Crest Stage Record I ~~~6.5 Evaporation Data I ~~~Evaporation data is necessary for mathematical modeling of the rainfall/runoff transformation using a soil moisture accounting method. j ~~~Estimates of potential evapotranspiration are usually based on either pan evaporation data or an analysis of available meteorological data. I ~~~The nearest evaporation pan to the study area is located at Matanuska, some 150 miles northwest of Homer. Because of the differences in climate at Matanuska and Homer, this data was not used for this study. I ~ ~~Rather, mean monthly-evaporation data were estimated using the nomograph presented by Kohler et al. (1955). Calculations were based 5 ~~~on mean monthly air temperature, relative humidity, wind speed and cloud cover recorded at Homer WSO. The estimated mean monthly evapora- 5 ~~~tion over the study area is given in Table 6.3. 5 ~~~6.6 Calibration of Anchor River Catchment The NWS Snow Accumulation and Ablation and Soil Moisture Accounting I ~ ~~Models are generalized hydrologic models which may be used in a wide variety of climatic regimes. Application of these models to a I ~~~~particular catchment or area requires that model parameters be set to represent conditions in the catchment of interest. The process by I ~~~which the parameter values are obtained is known as calibration. These models were calibrated to accurately reconstruct the flows on the Anchor River at the Anchor River stream gage for the period of record 1966-1970. Input to the models was provided by the time series of 5 ~~~precipitation and temperature data from Homer 5NW, and the estimated mean monthly lake evaporation data given in Table 6.3. Output from the 5 ~~~models include simulated snowpack conditions and simulated flows at the Anchor River gage. The model parameters were chosen and adjusted in an 3 ~~~iterative manner until the simulated flows from the model conformed as closely as possible to the observed Anchor River flows. 6-7 Table 6.3 ESTIMATED MEAN MONTHLY POTENTIAL EVAPORATION Evaporation Month (inches) October 0.8 November 0.3 December 0.3 January 0.3 February 0.3 March 0.3 April 1.4 May 1.9 June 2.9 July 2.8 August 2.2 September 1.2 Annual 14.7 N ~~~Good calibrations were achieved of the critical winter low flow condi- tions, adtetiming of spring snowmelt was simulated satisfactorily. I ~ ~~Peak flows during snowmelt were, however, overestimated, and the dura- tion of simulated snowmelt periods were somewhat shorter than recorded. The latter difficulties do not, however, affect the sizing of storage reservoirs required in this study. The adequacy of calibration is illustrated in-Figure 6.2, which shows a comparison of flow duration curves for the simulated and recorded flows. I~~~~~~~~~~~~~~- 7.0 ASSESSMENT OF SURFACE WATER SUPPLIES 3 ~~~7.1 General I ~~~~The initial phase of surfce water investigations has focused upon development of estimates of water yields from surface supplies identi- I ~~~~fied for possible use in earlier studies. These include, but are not limited to, the following: a. Anchor River/Beaver Creek. b. Increasing the capacity of the existing reservoir on Bridge Creek. C. Construction of a new reservoir on Twitter Creek. I ~~~~~d. Construction of a new reservoir on Fritz Creek. 3 ~~~~The locations of these sites are shown on Figure 1.1. 3 ~~~7.2 Anchor River/Beaver Creek These two potential sources of water supply were considered both indi- vidually and in conjunction with each other. Beaver Creek, being a tributary to Anchor River, is therefore part of the Anchor River water- U ~~~~shed.* 3 ~~~a. Beaver Creek is located about 7 miles northeasterly of Homer. The creek flows in a westerly direction, draining approximately a 10 3 ~~~~~square mile basin. It enters the Anchor River about 16 miles east of the mouth of the Anchor River. The only measured flow on Beaver Creek near its mouth was July 1970. The flow indicated a I ~~~~mean discharge of 8.93 cubic feet per second Wcs) as measured by 7-1 3 ~~~~~the U.S. Geological Survey. In order to maximize available water it would be necessary to construct a dam approximately two miles upstream from the mouth of Beaver Creek. Such a structure has been deemed unsatisfactory by the Alaska Department of Fish and 3 ~~~~~Game (ADF&G) for two reasons. The first is that Beaver Creek is a spawning creek for anadromous fish which would have to be guaran- 3 ~~~~~teed one-half the total flow and with provision to transverse the dam. The other major factor in rejecting Beaver Creek is that a major portion of the lower half of the creek goes through a wide, marshy basin which is a haven and feeding ground for moose. This area is several times the size of the winter feeding grounds in I ~ ~~~~the Fritz Creek basin. The area would be inundated were a dam to be built on Beaver Creek, and lost permanently as a feeding 3 ~~~~~ground. 3 ~~~~b. The Anchor River discharges into Cook Inlet at Anchor Point at the Town of Anchor Point. The Anchor River flows westerly across the tip of the Kenai Peninsula, draining a basin of approximately 226 square miles. Moving upstream approximately 3 miles to where the Sterling Highway bridge crosses the Anchor River, the drainage 3 ~~~~~area is reduced to 133 square miles. U.S. Geological Survey records indicate a minimum/maximum flow range from 20 cfs to 2240 3 ~~~~~cfs. The mean low monthly (Jan.-Feb.) range being 69 cfs. Statements have been repeatedly made by ADF&G personnel that any I ~ ~~~~diversion of water from (much less damming of) the Anchor River could be expected to be blocked by a very powerful lobby of sports and commercial fishing interests through the State Legislature. 3 ~~~~~There is a potential means of collecting water from the water- bearing strata beneath a body of water. This is called the Ranney Method and consists of a sunken caisson on shore which serves as a stilling well or pump sump. Well point screens are driven out into the sandy-gravelly layer beneath the stream bed and collect ground water. This water goes into the caisson and is subsequent- 7-2 I ~~~~~ly pumped out into the transmission main. Using this method there is no construction in the river and no intake withdrawing directly I ~~~~~from the river. 3 ~~~~~To utilize the Ranney Method of radial collector wells would involve sinking the caisson on land near the river, incorporating the pumphouse in the upper chamber of the caisson (but basically underground), installing 37,000 feet of transmission main along the Sterling Highway to about West Hill Road and construction of a I ~ ~~~~water treatment plant. The treatment plant is a common cost to any of the alternative sources studied. This may be one of the * ~~~~~more cost-effective alternatives as it could also have provisions to supply Anchor Point. In order to give this alternative serious consideration, however, two things must be done. The concept must be submitted for con- sideration to ADF&G and the Department of Natural Resources (since it is a ground water extraction well). If a favorable response is 3 ~~~~~received, then a small well should be drilled and a water sampling program initiated in order to determine the water quality 3 ~~~~~obtained, which in turn influences the water treatment plant design. I ~~~7.3 Bridge, Fritz and Twitter Creeks U ~~~These three creeks have, to one degree or another, been considered and studied in reports going back over 20 years. Reports dated 1962 (Soil U ~~~Conservation Corps), 1971, 1977, 1980 and on have been re-reviewed. Ultimately, Bridge Creek was developed as a new surface water source in 3 ~~~1975, which led to the abandoning of the unreliable ground water wells located in the vicinity of the new Bridge Creek dam. I ~~~The next step in this report was to ex'pand on the generalized nature of the previous reports. There were no' long-term flow records available 3 ~~~at Bridge Creek, Twitter Creek and Fritz Creek. In order to determine 7-3 N ~~~~the adequacy of available water supply where no records exist, the next step in the study was to simulate flows for each of the three creeks, I ~ ~~~based on the Anchor River flow simulation discussed in the previous chapter. 7.3.1 Simulation of Daily Flows: Twitter Creek and Bridge Creek The NWS models calibrated for the Anchor River catchment were used to simulate average daily flows at the Twitter Creek and Bridge Creek damsites for water years 1949 through 1972. As has been noted earlier, the continuous discharge record on Twitter Creek shows that this catch- 3 ~~~ment has a lower base runoff (cfs/mi2) than the Anchor River as a whole. The parameters obtained from the Anchor River calibration were 3 ~~~therefore adjusted to produce lower primary basef low and steeper initial recession rates. The effects of the parameter changes were * ~~~checked by comparing simulated and recorded flows at the Twitter Creek H ~~~~continuous record gage for the period of record, water years 1972-1973. A plot of simulated and recorded runoff for water year 1972 shows relatively good agreement between recorded and simulated streamf low. Input data for simulating Twitter Creek and Bridge Creek flows were again precipitation and temperature data for the period 1952-1973 from 3 ~~~Homer 5NW. The Homer 5NW record started immediately after a two-year period of very dry conditions. As this period (1951-1952) was thought to be important for determining the required reservoir storages, the I ~ ~~Homer 5NW record was extended back to October 1949 using the longer term record from Homer WSO. Precipitation data for 1949-52 was obtained simply by multiplying Homer 3 ~~~WSO data by the ratio of mean annual precipitation at Homer 5NW and Homer WSO for the period of common record 1953-72. Temperature data for the period 1949-5� was taken without adjustment from the Homer WSO record. The simulated monthly flows at the dam site I ~~~and the calculated drainage areas are given in Sections 9.2 and 10.2. 7-4 7.3.2 Estimation of Daily Flows: Fritz Creek Because of uncertainty about the precipitation regime in the area of Fritz Creek, mean daily flows at the Fritz Creek dam site were esti- mated by prorating the simulated flows on Twitter Creek for water years 1949 through 1972. Analysis of simulated data indicated that the runoff rate (cfs/mi2) from Fritz Creek was about 76% of that on the Anchor River. It was also shown that the runoff per square mile at Anchor River and Twitter Creek is about the same. It was thus assumed that mean daily runoff (cfs/mi2) from Fritz Creek was 76% of that simulated for Twitter Creek. The estimated flows for Fritz Creek were compared with the data from the partial record at the Fritz Creek gage. In most instances, agree- ment between simulated and recorded flows was satisfactory, although some large differences in peak flow did occur which could not be explained with the available data. However, such differences are not critical in the development of water yield from the reservoir. The -simulated monthly flows at the dam site and the calculated drainage area are given in Table 11.2. 7.3.3 Conclusions Historical flows were estimated by means of a simulation model. The estimated mean annual runoff from the watersheds of Bridge Creek, Twitter Creek and Fritz Creek sites are 4.9 cfs, 6.2 cfs and 9.9 cfs, respectively (3.2 MGD, 4.0 MGD and 6.4 MGD). The annual runoff in the critical dry year during the period for which flows were synthesized were 1.8 cfs, 2.25 cfs and 3.6 cfs, respectively (1.16 MGD, 1.45 MGD and 2.32 MGD). 7-5 8.0 REGIONAL GEOLOGY 8.1 General Geological descriptions of a general nature presented herein are based on the review of previous reports. Numbers in parentheses refer to the reports listed under References. It is the purpose of this section to present the relevant geological information and to point out its significance to the design and construction of dams. The main geomorphic elements consist of an escarpment of moderately indurated sedimentary bedrock immediately north of Homer and beyond this to the north an upland area of the same bedrock almost entirely -covered by glacial deposits. Dam sites described are on creeks incised in the upland and range from about 2.5 to 8 miles from the City. The Homer Spit, which extends about 4 miles southward from Homer into Kachemak Bay, is a narrow bar consisting of coarse beach gravel and boulders. Apart from the Spit, the only known sizeable source of alluvial sand and gravel is a pit at Anchor Point, located about 16 miles by paved highway west of Homer. 8.2 Bedrock The entire area is underlain at shallow depth by the Kenai Formation which consists of moderately indurated sandstone, siltstone and clay- stone, mainly in thin beds and lenses,'interbedded with a few thin lenses of fine conglomerate and manyth-in beds of subbituminous or 8-1 lignitic coal. Ferruginous masses and ironstone concretions are common (Waller, R. M., et al., 1968). The Kenai Formation is of Tertiary age I ~ ~~~and is believed to be up to 20,000 feet in thickness. Where observed in the study area the beds dip northerly about 4 degrees below * ~~~~horizontal. 3 ~~~~Excavated rock of the Kenai Formation, observed in quarries during a reconnaissance of the area, is broken down to sand and gravel sizes. Confirmation of the softness of the material is given by descriptions of the bedrock at the Bridge Creek dam site where it is described as "generally semiconsolidated into a moderately soft rock . . . cut I ~~~~easily with a knife and sometimes scratched with a fingernail" (Hill-Harned & Assoc., 1974). It is therefore expected that for dam 3 ~~~construction purposes quarries in the bedrock would not represent a source of rock fill but could well serve as a source of sand. 3 ~~~The Kenai Formation is described as probably constituting the most extensive and the most productive aquifer system in the area. However, I ~ ~~objectionable amounts of iron occur in the ground water throughout much of the area and some of the ground water contains methane gas probably 3 ~~~~derived from the coal formations (Waller, R. M., et al., 1968). 3 ~~~~High-ly permeable zones, of course, represent unfavorable features in a dam foundation. At the Bridge Creek dam site, coal beds were described as highly fractured and it was anticipated that water losses during pressure tests would occur through these fractures. While water losses at that site were also expected to occur through joints and bedding I ~ ~~planes of the siltstone and silty sandstone and not through the rock itself, some of the non-silty sandstones appeared to be porous, and * ~~~water losses were expected to occur through the sandstone itself as well as along joints and bedding planes (Hill-Harned & Assoc., 1974). This raises the possibility of piping occurring in sandstone beds in dam foundations should the piezometric gradients result in water flowing at velocities high enough to'mov e the sand grains. 8-2 U ~~~8.3 Overburden I ~~~~As a relatively short time has elapsed since the ice sheet that formerly covered the area receded, the Kenai Formation is mantled by 3 ~~~~nearly continuous deposits of glacial draft. The deposits of this material observed during the reconnaissance appear to be unsorted * ~~~mixtures apparently deposited directly by glaciers and consisting of clay, silt, sand, gravel and boulders. These deposits are referred to herein as glacial till. The largest boulders observed in this material U ~ ~~are in the order of 2-ft. diameter. While it is reported by others that some of the glacial drift deposits consist of stratified gravely I ~~~outwash material, and a few boulders greater than 2-ft. in diameter were observed during the reconnaissance, for general planning purposes 3 ~~~~it is taken that the overburden at the dam sites discussed herein consists essentially of the unstratified glacial till described. I ~~~This material is believed to have extremely low permeability and, while not well consolidated near the surface, appears to be suitable to serve I ~~~as a dam foundation and as impervious core material for an earth-fill' dam. Regarding the depth of overburden, it is noted that during a soil 3 ~~~survey of the area reported in 1971 (U.S.D.A., 1971), to expose soil profiles many holes were dug through the topsoil into the parent material. Although in the great majority of the holes the parent U ~ ~~material was found to be glacial drift, some of the holes encountered bedrock. As the soil directly overlying bedrock at shallow depth was given a special designation, Kachemak silt loam, occurrences of this soil mapping are of interest in estimating the depth of overburden in 3 ~~~the study area. Widely distributed occurrences of the Kachemak silt loam indicate the possibility of bedrock occurring at shallow to moderate depth at all of the dam sites. At the Bridge Creek dam site, however, by exploratory drilling the depth of overburden was found to be as great as 34 feet on the right (north) abutment (Hill-Harned & I ~~~Assoc., 1974). 8-3 Topsoils in the study area are mainly silty oarns 2 or 3 feet thick but include in muskegs peat soils comprising mats of moss and peat many I ~ ~~~feet thick (U.S.D.A.5 1971). The majority of the soils are rated from moderate to high in corrosive acidity potential (Hill & Assoc., 1972). 8.4 Seismicity The results of seismic hazard analyses are presented in previous reports, (Hill-Harned & Assoc., 1974; CTA, 1974). It has been found that: I ~~~a. Every year in the Homer area there are numerous earthquakes of Richter magnitude 4 to 5 and there has been in historical time an 3 ~~~~~earthquake of magnitude 6.5 located approximately 20 miles south- west of the Bridge Creek dam site and an earthquake of magnitude 3 ~~~~~6.25 seven miles northeast of that site. b. No surface ruptures or displacements of significance appear on any I ~ ~~~~geologic maps of the Homer area. 3 ~~~C. Past events in historical time have probably caused, at the Bridge Creek site, bedrock accelerations up to 0.35g with a predominant 3 ~~~~~period of 0.35 seconds and it is reasonable to treat this as the maximum acceleration to be expected in the future. I ~~~d. Although the area is within an Earthquake III zone, it appears that it is within one of the quieter or less active areas of Zone I ~~~~~~III. 3 ~~~Regarding the response of dams to earthquakes, it should be pointed out that safety of an earthfill damn depends to a great extent on the pore 3 ~~~pressure build-up and deformation characteristics to be expected under earthquake conditions. Dams of clay fills on clay or rock foundations 3 ~~~~have withstood extremely strong shaking, producing horizontal forces of 8-4 0.35 to 0.8g caused by an earthquake of magnitude 8.2 with no apparent damage (Seed, H. B., Geotechnique, Vol. 29, No. 3, 1979). Improvements in design and construction methods have tended to counter- U ~~~act the effects of inertia forces related to dam height. Slippage is not generally due to the inertia forces under the shaking action but to 3 ~~~reduction of shear strength caused by high pore pressures induced (especially where silty material subject to liquefaction is present). 9.0 BRIDGE CREEK ALTERNATIVE 9.1 General This alternative involves increasing the storage capability of Bridge Creek by raising the existing dam. 9.2 Streamflow Synthesis The drainage area at the Bridge Creek damsite is 3.6 square miles. Input data for simulating Bridge Creek flows were precipitation and temperature data for the period 1952-1973 from Homer 5NW. The Homer 5NW record started immediately after a two-year period of very dry conditions. As this period (1951-1952) was thought to be important for determining the required reservoir storages, the Homer 5NW record was -extended back to October 1949 using the longer term record from Homer WSO. Precipitation data for 1949-1952 was obtained simply by multiplying Homer data by the ratio of mean annual precipitation at Homer 5NW and Homer WSO record. The NWS models calibrated for the Anchor River catchment were used to simulate average daily flows for water year 1949 through 1972. The simulated monthly flows at the damsite are given in Table 9.1. Since no streamflow measurements have been recorded at Bridge Creek, the simulated flows represent the best available data upon which to make estimates of reservoir yield and the mean monthly flows for 24 years are shown in Figure 9.1. It is noted that the flows have double peak, one occurring in spring and another occurring in fall. Low flows occur in winter and'summer. 9-1 inmmmmGmimrnm~imminmm TABLE 9.1 SIMULATED STREAMFLOW, BRIDGE CREEK, cfs ENTER SU8POUTINt H1I4T 1TW1W~~~~~~~~~~~~~~~~~~~~~~~~.l --.--"U KJ r 152398 51 49 .53 5.119 1.93 I1.20 1.0 3 1. 30 6.02 17.27 5.144 2.1L 1.41 3.0. 4..4C T513913T~~56 67,09, 'W.5 -J1 1.56" r "-f- -Co-.T.2, Z-.o 1. 31 1a -.1 0 ';o; 15239851 51.2.40 2.03.1.0'4 1.42 1.03 .93 7.4m 5.34 1.02 1.14# 1."' 2.40 2.15 15239851 53 7.091 71.64 7.23 6.00 2.34 1.74 13.917 17.61 11.20 I.?? 1.4t 4.67 7.5p 15239851 55 7.13 7.39 2.60 1.9 1.49 1.20 2.28 20.97 5.0.1 1.99 1,%(% 2.as. 41.57 15239851 57 5.21 5.04 3.8 1A .5 1.66 7.21 6.13 1.'40 1.22 1.38 6.69 j.b.3 1~~zT9~~3r-5r r~~~17---1-y-7Q-=. S 78T # T7I3T3-TT. TT- 1.45 -4 .46 -WW5 -6. TV7 15239851 59 91.17 5.39 2.ol 1.5? 1.30 1.04 4.81 31.11 4.61 Z.56 1 . 59 1.9 0 5. 34 '.0 15239851 61 91~~~~~~~~.96 - .0m 11.61 15.33 4.01 1.76 4.5%4 11.21 -. 240 1.14 1. 71 li.2 6. 5' -7. r *5.9. ";73E '7W 2.46 T-45. 7 * 15239851 63 2.791 5.14 3.83 10.26 4.03 3.67 4.44 4.09 -1-5 5 1.14 1.47 2.50 3.75 13239651 65 6.58 3 .57 I.78 1.18 1.02 4.20 13.910 18.19 6.26 2.51, 2.17 5. S- 5.55 15239851 67 9.49 3.21' 1.85 1.29 1.12 1.02 2.95 19.75 3.07 1.51 3.7? 10.16 49 ME439051 bO -=5u-'- 926 4.3 ---3=. ' s 1.1 d.'9 J.'91 is.-Jz Z.VD3 T7 5' -T;Tg --T ~-3- 15239851 69 1. 30 1.44 1.10 .83 .74 ~,v s.91 14.86 3.1.0 1.53 1.20 1.09 2.77 1223'9521 tU - . '10 5.937-*.3'Y ~ U J.'#0 '..3. D..F A j. la inp, --I7.0 * 3'**4 -**7 1523'9851 71 14.791 7.34 1.95 1.24 2.00 1.20 .94 10.913 40.50) 3.72 1.0? 2.0. 0.53 .I C V~~.10 J .2 4 4.0 l AC a.0 L.11 1 .00 z.2% 10.0I 7."I x1vr %1 1..1 2. 31 ST. DEV 2.28 4.45 2.'IO.3.30 .98 1.07 3,79 7.63 7.60 hi~ 1.2t) 3.16.-.3 FINISH MIONSt 9.3 Water Yield I ~~~The design of a reliable water supply is based on the firm yield concept in which the supply is designed to meet demands during the most I ~~~critical low-flow periods, which in this case would be represented by the period July 1950 through September 1951. The mass curve approach was used in determining firm yield. A mass curve such as that shown in Figure 9.2 is a plot of cumulative flows with time. A mass curve of inflow represents the total amount of water passing through a given point in a river with time. The mass curve of I ~ ~~inflow shown is for the dry period 1950-1951 and was adjusted for downstream use for the required release of 700 gpm (1.0 MGD) or the 3 ~~~actual flow in the river, whichever is less (L. Farnen, 1982). A mass curve of outflow can also be drawn on the same plot and this represents 3 ~~~the total amount of water that could be withdrawn or utilized. The slope of the mass curve of outflow would be the rate at which water could be withdrawn. The difference in volume between the mass curve of I ~ ~~outflow and inflow is the amount of water that is withdrawn from reservoir storage and the maximum ordinate between these two curves is the size of the reservoir that is required to accommodate the stored water. The existing storage capacity at Bridge Creek is 470 acre-feet. 3 ~~~It is seen in Figure 9.2 that this storage capacity would allow a with- drawal rate of 0.66 MGD which is defined as the firm yield. Since the dry period occurred once in 24 years, it can be concluded that the data predict a water yield of 0.66 MGD or greater in 23 out of 24 years of record or a confidence level of 96%. A similar analysis could be U ~~~performed on the next driest period and the confidence level that would be obtained would be 22 out of 24 or 92%. A plot of water yield versus 3 ~~~~confidence levels is shown in Figure 9.3. The graph shows that, at 90% confidence level the data predict a firm yield of 0.69 MGD, and that at 3 ~~~95% confidence level would predict 0.58 MGD. In other words, the data suggest that Bridge Creek reservoir wi'll supply 0.69 MGD nine times out of ten and 0.58 MGD 95 out of 100. Larger yields than 0.69 MGD could be predicted but with a lesser degree of confidence than 90%. 9-3 * ~~~Comparison of these results to the actual and projected water demands (Figure 9.4) shows that the Bridge Creek reservoir firm yield is likely to be reached in the near future. 3 ~~~As demand increases with time, or if demand grows at a faster rate than expected, the odds against the City being able to meet all demands 5 ~~~increases. Hence, the City may wish to consider the risks and conse- quences of insufficient supplies in planning for water system develop- ments, or wish to consider means by which to prevent rapid increases in water consumption. 1 ~~~9.4 Evaluation of Bridge Creek Reservoir Expansion 3 ~~~A technique by which the City could increase the safe yield from the existing reservoir would be to increase the effective storage capacity by raising the height of the dam. The effect of increasing the height of the dam woul d be to permit more water to be stored during wet periods for subsequent use during dry periods. The topographic and 'I ~ ~~geotechnical considerations for developing this alternative are dis- cussed in the following sections. 1 ~~~9.5 Topography and Geology - This section is from reports previously reviewed (Hill-Harned & Assoc., 1974; C. A. Hill & Assoc., 1972). The valley floor at the Bridge Creek Dam site is about elevation 900 3 ~~~feet and the creek has incised a channel about 30 feet deep with a floodplain about 50 feet wide in the valley bottom. The slopes of the 3 ~~~valley rise on 7 to 8 percent grades to ridge tops at about 1100 to 1200 feet elevation. Outcrops of sandstone and siltstone occur at scattered locations along the south bank of the creek. Elsewhere the bedrock is mantled by glacial drift. 9-4 Before construction of the dam, the site was investigated with seven boreholes in the vicinity of the proposed axis and with numerous test pits. Gray siltstone and sandy siltstone were found to constitute over 60 percent of the geologic section tested, with sandstone comprising less than 30 percent and coal comprising about 10 percent. The surface of the Kenai sandstone and siltstone was found to be weathered and * ~~~decomposed with relatively fresh rock occurring below about 2feet; however, the bedrock throughout appeared to be fractured. Coal beds 3 ~~~encountered were highly fractured and it was anticipated that water Tosses would occur through the fractures. I ~~~The mantle of overburden was deepest on the right abutment where it consisted of one foot of organic soil over 4 feet of soft silty clay 3 ~~~overlying 34 feet of compact to dense glacial drift overlying the Kenai Formation. The drift was generally compact to very dense and was 3 ~~~described as consisting of stratified silt, sand and gravel (CH2M- Kill). However, water losses during the drilling and packet tests performed indicated the glacial drift to be low in permeability. Penetration resistance tests showed that the glacial drift has a high * ~~~strength and is relatively incompressible. Because of the gentle slopes, no landslides or areas of potential land- 1 ~~~slides were noted in the reservoir system. 3 ~~~9.6 Raising Bridge Creek Dam The dam section at Bridge Creek is shown in Figure 9.5. It is believed that raising Bridge Creek Dam would be very expensive and quite impractical. The design problems described below arise from the fact 3 ~~~that Bridge Creek Dam has never been intended to be raised by its designers. a. The internal zoning of the existing dam narrows toward the crest. The central core, Zone 1, would have to be continued upward in a narrow upstream-inclined zone, and Zone 3 would have to be turned 9-5 N ~~~~~section of the existing dam. Thus, the dam would not only have to be raised, but widened at least toward downstream. b. The hydraulic gradient, H/L, governing the underseepage and uplift 3 ~~~~~conditions within the dam foundations, already unusually steep for a dam sitting on a highly erodible foundation, should certainly 5 ~~~~~not be steepened. Thus, if the head, H, is increased the internal impervious blanket under the upstream shell of the dam would have to be continued farther upstream. This cannot be done without dewatering the reservoir. 1 ~~~~C. The outlet structures would have to be relocated and/or reinforced to accommodate the widened plan area of the dam. 3 ~~~9.7 New Downstream Dam An alternate to raising the existing Bridge Creek Dam would be to move downstream and construct a new high dam. Ignoring ADF&G's release rate requirement to sustain fish population and that because of this 5 ~~~release, that no more useable storage would be obtained beyond that presently available from the existing dam, other factors negated this 1 ~~~~alternative. The present worth in today's dollars of the existing dam and appurtenances would be discarded with no salvage value. The cost of the new dam, spillway structure and intake structure would be incurred at today's dollars. In addition, raising the lake surface significantly would flood the pumping station, which would have to be 5 ~~~rebuilt at a higher elevation. When considering the effects of build- ing a totally new dam downstream, it was concluded that it would not be 3 ~~~cost-effective for the amount of water obtained. 9-6 10.0 TWITTER CREEK ALTERNATIVE 10.1 General This alternative includes providing a storage reservoir by constructing a dam at Twitter Creek. The proposed dam will be located in Section 32 opposite Ohlson Mountain (Figure 1-1). 10.2 Streamflow Synthesis Analysis of the continuous discharge record from Anchor River and Twitter Creek shows that runoff was nearly the same at these two sites for water years 1972 and 1973. This suggests that the long-term mean annual runoff on Twitter Creek is similar to that for the Anchor River as a whole (i.e., approximately 1.5 cfs/sq. mi.). The concurrent monthly flows for Anchor River and Twitter Creek are plotted in Figure 10.1 for the period of record available on Twitter Creek. This plot indicates that Twitter Creek has consistently lower winter base flows and somewhat higher peak flows than the Anchor River. The higher base flows on the Anchor River probably arise from storage of water in marshland bordering the river channel. Comparatively few marsh areas are found in the Twitter Creek catchments. Data from the partial record station on Twitter Creek near Lookout Mountain are given in Table 10.1, along with the concurrent mean daily flow at the Anchor River gage where available. The runoff measurements (cfs/sq. mi.) at the partial record gages are plotted against the mean daily runoff (cfs/sq. mi.) at the Anchor River gage in Figure 10.2. 10-1 TABLE 10.1' PARTIAL RECORD DATA, TWITTER CREEK Twitter Creek Anchor River Date Near Lookout Mountain Near Anchor Point 07/13/78 1.7 08/18/78 1.2 09/15/78 1.1 136.0 10/10/78 1.4 202.0 11/09/78 2.1 148.0 01/12/79 1.2 125.0 03/19/79 0.49 80.0 04/17/79 1.0 190.0 05/03/79 14.0 933.0 05/15/79 12.0 521.0 05/30/79 4.2 246.0 06/15/79 1.5 111.0 07/19/79 0.88 104.0 08/16/79 0.97 95.0 03/05/80 1.1 150.0 07/23/80 2.4 154.0 09/04/80 1.4 111.0 10-2 Also shown on these figures are 45 degree lines through the original indicating the line the data would fall on if the runoff per unit area were equal at both the partial record gage and the Anchor River gage. The data from Twitter Creek near Lookout Mountain (Figure 10.2) are inadequate for determining the relationship between flows on Twitter Creek and the Anchor River. The data available do, however, indicate somewhat lower base runoff and higher peak runoff than is found on the Anchor River. This agrees with the comparison of-continuous records from Twitter Creek near Homer and concurrent records from the Anchor River discussed earlier. The drainage area at the proposed damsite is 4.6 square miles. Input data for simulating Twitter Creek were again precipitaiton and tempera- ture data for the period 1952-1973 from Homer 5NW. The Homer 5NW record started immediately after a two-year period of very dry condi- tions. As this period (1951-1952) was thought to be important for determining the required reservoir storages, the Homer 5NW record was extended back to October 1949 using the longer term record from Homer WSO. Precipitation data for 1949-1952 was obtained simply by multiplying Homer WSO data by the ratio of mean annual precipitation at Homer 5NW and Homer WSO for the period of common record. Temperature data for the period 1949-1952 was taken without adjustment from the Homer WSO record. The simulated monthly flows at the damsite and the calculated drainage areas are given in Table 10.2. The NWS models calibrated for the Anchor River catchment were again used to simulate average daily flows for water years 1949 through 1972. As had been noted earlier, the continuous discharge record on Twitter Creek shows that this catchment has a lower base runoff (cfs/sq. mi.) than the Anchor River as a whole. The -parameters obtained form the Anchor River calibration were therefore adjusted to produce lower 10-3 TABLE 10. 2 SIMULATED STREAMFLOWS, TWITTERk CREEK, cfs SIM6LAI.EJ FLOi'S TOITTEk Cit DAMf 4.6 sq. mi. S rAT ION w*yi 13Cl Mif DEC JAN O:FP *iAP0 APR MtAY JUN JUL AUG SEP ANNJAL 1523QI%46 .9 6.3.. 6a.3 2. 34 1. b% 1. 3? 1.66 7.69 22.o0. 7.0 .. .6 .s 56 L 5;.-3' a4,a ~ O 7. 76 13.tbl $..39 2 000 1.516 34.7 12.30 9.60 2.63 1.07 1.1 I.'7 5.23 LJ298so 5 3.07 7...' 10.39 1.62 1.31 1.121 9.5t. 6.62 2.33 1.48 1.31 3.18 3.30 152394;6 52 2.d5 4.12 2.03 1.2;. 1.09 .99 2 .ilk 5.5b 2.29 1.52 1.25 1.66 2.25 --v-3 -g'A I- x) .. . -- 7. ... 7tv5. -9,23- .7.6 -...9 2.Z22 17.,47 22.50 6.65 -2..Zb. 7..'i 5.96 9.5 15239846 5 4 6.29 S.1I4l 3.66 2.17 I. 1 .29 5.70 Zo.zz J.9b 2.04t 3.92 4.5 .6 k12398 6 b; 9.11 9.45 3,32 2.03 1,91 14~4 2.92 26.60 7.17 2.5f. 1.71 3.01 salb 1523964o So 7.3o 3.72 ~~~~~ ~~1.77 1.37 I.?l 1410 5.49 Z7.30 cl,72 2.43 2.30 3.41#1 5.35 i~~j39846.~~~~~ 6.,64 ~~~~~ .4.019 2.32 7.75 2.32 9.23 7.84 2.30 .1.55 1.76 J.55 6. b4I 1523984o ~~5d 11.33 19.53 7.04 2.43 1.7? 1.62 16.94 16.63 .36 4#.41 5.70 7.13 O.bl -I -.15239dl4"1. a~ 9 16& 1.33 .6.14 ?.5 .3.9.3.LI .1.. .g 61 15239846 60 4~~~.31 .6 3.96 2.15 1.47 1.I 3.56 40.048 5.95 3 .141 6.52 8458 7.37 1.1~~~~~~Z5 8.6 ..5 43.a 19.5; 5.13 ?.25 5.93 L11.33 3.16 2.22 .2.21 146.20 6.36 323946 112 'O.'5-3 7.58 6.85 2.1.2 1,1.A9 1.69 8.43 31.1 4 10.36 3.15 1.86 1.76 7.2Z4, * 1.5239u#o a) . . 9 tp ,t-$ 7 -t Q ~~ 11.. .5. 4,19 5.67 5.22 .1 *19 .s14.'5.. 1,.86 3.26 It.7 9 ;15239846 04. 7.70 3-30 10.09 4026 2.b?1.1 03 3.12 19.43 10.32 2.62 2.21 2.96 5.59 M53986h p641, 't-l- .. .-ZAJ... 1..3.0 ....3 7 1.7.3.6 Z ..8..j.k.. 15239846 66 7.46 2.66 1.73 1.41 1 .2'1 1.15 6.46 26.9y U.4-k1 2.819 7.09 I4 .70 6.85. IS23Q86~~~~y..J~~jj ~~ ...L4? ..i...~~~~65 .A..4~3 1.30 3.77 25.2 -.4 1.3. 4.82 12.98 .6.3I 15239846 Du 5.75 Li1.84. 58 3.99 4.10 3.410 5.03 17.76 3.74 1.65 1.49 1.41 5.53 15239114bi j.; ?O.,N.1.51.A0 .9 L2., 6.28 16.99 A4.S Z. 2 ..15 3 L ..h .a.5a 15239640 70 12.47 ~~~~~6.33 11.18 5.13 4.44' 5 . 5 7.29 30.39 4.67 2.14 2.31 4.39 a.32 15239646 71 6.10 9.38 2.50 A ...2.. .1. 5-4 .A . L20.O&-~...2.6.. 15239646 12 12.47 . 4.59 2.22 1.6 131 1.73 1.10 30.36 15.01 3.17 2.73 9.96 7.15 ***AR## EF IN FILE 2 AFrER wyj.-- SAMPLE SIZE 2 2. 4 2 4 2 4 2 4 24 24 14 'lEAN ~~~~~~7.59 73. 47 3.5; 1 a.15 720 21.2 -.4 25 .7 .5 2 h92 5.69 .3.~~~~~~~~4 4.22 .1.~~~2.26 1.37 14.63 9.75 9.71 ..a? 1.62 4.03 1.77 primary baseflow and steeper initial recession rates. The effect of the parameter changes was checked by comparing simulated and recorded flows at the Twitter Creek continuous record gage for the period of record, water years 1972-1973. 10.3 Water Yield Water yield for Twitter Creek was evaluated in the same manner as for Fritz Creek. Streamflow estimates from the simulation model were used to determine firm yield from a reservoir on the creek assuming 60% of the actual flows or 60% of the long-term mean annual flow as the instream flow requirement. Analysis conducted predict that the firm yield from the site would be 1.98 cfs (1.28 MGD) if 60% of the actual flow were maintained as instream flow and the reservoir size required would be 1500 acre-feet. Using the same size of reservoir and applying the other criterion, i.e., 60% of the long-term mean annual flow or the actual flow, whichever is less, as instream flow would result in a firm yield of 1.36 cfs (0.88 MGD). These flows represent the yield obtain- able during a critical dry period such as that experienced in 1950-1952. 10.4 Topography and Geology The topographic and geologic conditions are similar to the ones exist- ing at Bridge Creek and at Upper Fritz Creek site. Any dam design, therefore, would be similar to any design developed for Fritz Creek. Topographic maps and the soil mapping units given in the soil survey report (1), were reviewed. The topographic map illustrates that the Twitter Creek confluences with the Anchor River and Bridge Creek occur at approximately elevations of 400 and 500, respectively, while the headwaters of Twitter Creek are found at approximately elevation 1400 feet. Along the lower reaches of the creek the valley slopes rise to ridges along both banks at elevations ranging from 700 to well over 1000 feet. The slopes are 10-5 indicated to vary in gradient from maximums of about 30 percent at locations immediately above the narrow floodplain of the creek. Numer- ous gullies occurring in the slopes appear to have been eroded in the glacial till. Although no outcrops are known to occur in this vicinity and the creek appears to have been incised essentially in glacial till or other glacial drift deposits, numerous occurrences of the Kachemak soils on both banks indicate the possibility of bedrock occurring at shallow depths along Twitter Creek upstream from its confluence with Bridge Creek. 10.5 Preliminary Project Arrangement The project will consist of a dam approximately 100 ft. high, a morning-glory shaft spillway, an emergency auxiliary spillway to pass unusual floods, a low-level outlet works and a pump house (Figure 10.3). Water will be conveyed from Twitter Creek to Bridge Creek reservoir through a buried steel pipeline about 2.5 miles long. The pipeline will have to cross Crossman Ridge which is at Elevation 1200. Pumping will be necessary to deliver water to Bridge Creek. There will be three pumps, each rated at 75 HP at 300 ft. total dynamic head. One of the pumps will be for standby use. Normal pool level will be at El. 1085. Minimum pool will be at El. 1010. The dam will be an earthfill structure with slopes of i on 3 and would be constructed using: a. A massive impervious core and some impervious blanket constructed of compacted clay-silt-sand-gravel and cobble mixtures, i.e., of compacted glacial till; b. A minimum amount of compacted clean sand in the upstream shell zone subject to drawdown, and further such sand for filters (which may be replaced, alternatively, by filter cloth); 10-6 c. Processed clean, coarse sand, or coarse sand and gravel, for an internal drain layer, frost-proof crest and "rock" toe; d. Random organics-free sand or gracial till fill for the downstream shell; and e. Riprap on filter cloth protecting the upstream reservoir slope as well as the dam toe at tailwater. 10-7 11.0 FRITZ CREEK ALTERNATIVE 11.1 General This alternative involves providing a storage reservoir by constructing a dam. Water would be piped to the Homer distribution system, which is 6.5 miles away. 11.2 Streamfiow Synthesis 3 ~~~Because of uncertainty about the precipitation regime in the area of Fritz Creek, mean daily flows at the Fritz Creek dam site were esti- mated by prorating the simulated flows on Twitter Creek for water years 1949 through 1972. 3 ~~~~Data from the partial record at Fritz Creek with the concurrent mean daily flow at Anchor River are shown in Table 11.1 and plotted Figure 3 ~~~11.1. Also shown in this figure is a 45 degree line through the original indicating the line the data would fall on if the runoff per unit area were equal at the Fritz gage and the Anchor River gage. A linear regression analysis indicated that the mean annual runoff per square mile on Fritz is about 76% of that on the Anchor River or about I ~ ~~1.1 cfs/sq. mi. It is also shown in Section 6 that the runoff per square mile at Anchor River and Twitter Creek is about the same. It was thus assumed that mean daily runoff (cfs/sq. mi.) from Fritz 3 ~~~Creek was 76% of that simulated for Twitter Creek. The drainage area at Fritz Creek is 9.6 square miles. TABLE 11.1 PARTIAL RECORD DATA, FRITZ CREEK Anchor River Date Fritz Creek Near Anchor Point 07/13/63 12.3 10/02/63 9.56 06/05/64 31.5 06/19/64 17.5 07/22/65 9.42 06/01/66 26.3 639.0 07/12/66 24.1 377.0 08/16/66 6.97 116.0 09/19/66 45.5 1170.0 03/27/67 3.34 55.0 05/23/67 12.0 240.0 06/13/67 14.1 203.0 07/26/67 3.99 82.0 09/03/67 7.56 152.0 10/21/67 8.44 135.0 04/14/68 2.15 92.0 08/01/68 2.50 72.0 08/20/68 4.57 75.0 10/22/68 3.34 58.0 01/13/69 0.85 28.0 03/19/69 9.41 60.0 05/07/69 28.0 350.0 06/23/69 7.17 111.0 11-2 TABLE 11.1 (continued) Anchor River Date Fritz Creek Near Anchor Point 07/31/69 4.84 78.0 09/08/69 2.70 58.0 10/12/69 47.2 747.0 03/04/70 6.81 160.0 03/19/70 28.2 200.0 06/25/70 6.76 161.0 07/24/70 4. 86 124.0 08/08/70 6.21 109.0 09/29/70 4.68 113.0 11/12/70 19.0 272.0 03/22/71 3.16 74.0 07/16/71 12.8 224.0 08/28/71 7.85 112.0 04/01/72 1.78 80.0 05/10/72 61.0 1000.0 05/26/72 25.3 570.0 07/07/72 6.23 107.0 08/15/72 10.1 166.0 10/07/72 23.0 269.0 05/10/73 29.0 510.0 06/20/73 12.0 197.0 10/10/73 22.0 06/21/74 6.8 10/09/74 12.0 05/14/75 76.0 11-3 TABLE 11.1 (continued) Anchor River Date Fritz Creek Near Anchor Point 06/11/75 31.0 09/11/75 32.0 05/20/76 26.0 05/04/77 39.0 08/08/77 3.6 07/11/78 6.1 08/16/78 3.2 09/15/78 8.8 136.0 10/10/78 12.0 202.0 11/09/78 8.9 148.0 01/05/79 6.7 125.0 03/14/79 4.8 76.0 04/17/79 14.0 190.0 05/01/79 53.0 947.0 05/15/79 27.0 521.0 05/30/79 11.0 246.0 06/15/79 5.0 111.0 07/20/79 4.9 100.0 08/16/79 3.6 95.0 11/29/79 91.0 1250.0 03/05/80 7.7 150.0 05/01/80 68.0 844.0 07/23/80 8.9 154.0 09/05/80 5.5 106.0 11-4 I The estimated flows for Fritz Creek were compared with the data from the partial record at the Fritz Creek gage. In most instances, agreement between simulated and recorded flows was satisfactory, although some large differences did occur which could not be explained I ~ ~~with the available data. However, these differences are not critical in the development of water yield from the reservoir. The simulated monthly flows at the dam site have been shown in Table 11.3 Water Yield Stream flow estimates applied to Fritz Creek were used to determine I ~~~estimates of firm yields. As with the case of Bridge Creek, provision for maintaining instream flows has a great effect on the firm yield 3 ~~~available for municipal uses. Criteria for providing instream flows was provided by the Alaska Department of Fish and Game (D. McKay, ft ~~~1982). The instream flow criteria are: a. 60% of the instantaneous flow b. 60% of long-term mean annual flow or the actual flow, whichever is 31 ~~~~~less I ~~~~In both cases, the criteria developed by ADF&G was intended to be conservative (D. McKay, 1982) subject to further analysis and revision in light of additional stream data. Thus, for purposes of evaluation I ~ ~~these criteria have been used to determine the effect on reservoir sizing. A mass curve analysis using Criterion I and the driest period j ~~~~of record (May 1950 - March 1953) with a reservoir storage capacity of 2300 acre-feet would provide a firm yield of 1.87 MGD. A similar mass I ~~~~curve analysis using Criterion 2, provided a yield of 2.30 MGD with a correspondingly larger size reservoir of 4900 acre-feet. These results R ~~~~are given in Table 11.3. -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "a Mn - m-m TABLE 1.1 .2 SIMULATED STREAMPILOWS, FRITZ CREEK, .cfg* Ii' TULM -.E 10M. ilUAE LUWS MTZ CX.DAM 9.6 sq. mi. U14110" dva UCt mEOV ' DEC JAN FE A AR fAY J UN JUL AUG sip A -4N JA L k2LL~~~A0J.4e 3.24 **3.7~~~~~~~~ ~~,.4'. .L,~~~~ALO3.. -1.haal. .ILL.15 .2 7 .2.85 6.26 .. 1523'I~~ul 5.1 ~12.3, 2.0 ,7 3.1 2.45 5.9 3 19. 51 153 .6 2.66 2 .24 Al.12 a 13239531 51 4 #1_l A -9 .8 35 2S07 5*5 o? joajq~~o4.5 6. 53 32 2.4 173 1 . 56 3 .46 6.62 3.b3 2.1,13 1,9 2.95 3.57 15239501 53 43 3.8 1.5 12.1? 474 3.5 3 27. 72 5.-7i I*,3. .1 5- Jil.99 ...i s52J9501 54 13.lo 8.~~~1115 6.12 3,45 2. 37 2.35 9.L3 41 .62 6.29 S.2Z46 6.22 .2 90 1524401 5, 14.46 14.99 5.28 _.17 1. 03 .4 O ,.* .4 O) Z P. Os4A..?.. .9.sb i5239pol 2 b 1 l Ij.ta 9 1.6 2.17 1.9? 1.74 6.71. 43.33 L0.66 3.86 3 .84 5.41 8.49 A52395~~1 5710.5b 1042 ~~~ iJL......1-i,-AL.. .1.L &AI 3.6624. 2 13.57 ..3 l5239501 56 17.90 30.99 11.17 J.81 2.72 ?-57 30.06 Z9.8d 6.%4 7.01 9.0 4 12.26 13.66 a ~~~~~~~~15ZA9501 69 12.52 10.76 *.....__Z.I?,1 2.63 *2.11 9.72 73 ad~ 9.�,A4.. . L3- J.9 ....I.......�I 13 i6.. - * 152k39001 60 6.65 10.57 6.29 3.412 2.33 1.40 5.66 64.2,4 9.45 6.55 10.34 13.bZI2 1. S . 1~239501 61 141.11 -- 3I9- **LOOJ~~ . AkQ..jiL- 5.8.02. 3.13 3-0.15 22,.. Ss'-1.Z 15239531 62 15.13 12.03 10.88 4.16 2.68 3.00 13.38 949.4t.2 16.46 4.91 2.94 2.63 III-# 132393ul 63 S.63 ( 10.4 1!- f 2j ?, i ...L -i .JJ 2.30 2.9. .0. 15239501 64 12.22 5.24 16.01 6.76 4.24 2.90 4.95 30.84 lb.09 4.16 3.51 4.13 q.35 15239501 65 13.35 7.24 3.61_ 2.39 2.06 It.5 2 27.56 36.88 -12,.oP9 j J.ili 11.15 1 1' 1~239501. 60 11.d5 4.22 2.74 2.24 2.01 1.63 10.25 Is2.(J3 13.35 4.;9 11.24 23.33 10.67 15Z39501 61 19.204 6.651 3.7 _ I 11. _ 2.27 2.06& 5.98 40 OA.4 6 .j2.)31 Q 15239501. 68 9.13 la8.16 8.90 6.34 6.50 6.33 7.9b 28.22 b .,4 2.34 2.36 2 .24~ a.?6 45239501, 70 19.79 10.034 17.74 3.1'. 7.05 8.90 11.58 of .22Z 7.41 3.39 3.67 6.97 12.73 15239501 71 9.68 14.a8 1.96 2.51 4.06 2.44 1.90 21.66t 821.13 7.54 4.00 4.16 13 .2 4 16239501 72 19.78 7.28 3.52 2.413 2.16 1.95 1.75 45.18 23.62 5.03 4.33 15.8#4 11.35 U$*'WARN*** EOF IN FILE 3 AFTER WY 2. 5AMPLE SIZE 24 24 2 . 4 24 24 24 24 24 24 24 2 .IEAN 12.05 12.08 7.46 . 3.4*7 3.40 143 33.7621 ?4.j Z.3 -.6 9.88 ~~ro. 0EV ~~~~4.63 -9.02- 5.47- -u6t.- 1.99 2.17 7-bb- _1.I7i.13.L. -,7 0-.3 ..o~so Z. 2.62. F INI St ION S o - \ - - - - - m - - - -: TABLE 11 .:3 EFFECT OF INSTREAM FLOW REQUIREMENT, Fritz Creek Criterion 1 Criterion 2 Criterion 1A Criterion 2A 60% of Actual 60% of Mean Annual 28% of Actual 28% of Mean Annual Yield, 2.9 cfs (1.87 MGD) 3.56 cfs (2.30 MGD) 5.3 cfs (3.42 MGD) 5.3 cfs (3.42 MGD) Reservoir size, 2300 4900 4000 5800 acre-feet Add: Bridge Creek 0.90 cfs (.58 MGD) 0.90 cfs (.58 MGD) 0.90 cfs (.58 MGD) 0.90 cfs (.58 MGD) Yield Total Yield 3.8 cfs (2.45 MGD) 4.46 cfs (2.88 MGD) 6.2 cfs (4.0 MGD) 6.2 cfs (4.0 MGD) Year 2030 Demand 6.2 cfs (4.0 MGD) 6.2 cfs (4.0 MGD) 6.2 cfs (4.0 MGD) 6.2 cfs (4.0 MGD) In comparing these results to average daily demands (ADD) projected to occur 40 to 50 years hence, it is observed that the combined firm yields of Fritz Creek and the existing Bridge Creek reservoir (0.58 MGD) under either criterion, would be significantly less than those future demands (2030 ADD = 4.0 MGD). To meet the year 2030 demands (4.0 MGD), it will be necessary to modify Criterion I or Criterion 2 to 28%. The corresponding reservoir volumes required would be 4000 acre-feet under a criterion similar to Criterion I1 (Criterion 1A) and 5800 acre-feet under a criterion similar to Criterion 2 (Criterion 2A). These data point to the need for the City to clarify with ADF&G instream requirements for Fritz Creek. The position of ADF&G has shown that for planning purposes the 60% requirement should be met (Criterion i or 2), after which more detailed studies of stream morphology might be required to re-evaluate and adjust the criteria. Analyses presented herein may provide the additional information upon which refined esti- mates of instream requirements can be made by ADF&G. Based on these studies, it can be concluded that the reservoir size would range .between 2300 acre-feet which is that required to meet Criterion 1 (Table 11.3), and 5800 acre-feet which is that required if Criterion 2 can be modified to 28% to meet 2030 demands. 11.4 Topography and Geology From the reconnaissance carried out along the valley of Fritz Creek, it appears that the creek bed and the slopes adjacent to the creek are underlain by deposits of glacial till. In the downstream reaches examined, the creek has cut deeply into the soil mantle, resulting in relatively steep continuous valley slopes with gradients commonly in the order of 40 to 60 percent rising from the floodplain which is limited to widths on the order of 50 feet. Numerous indications of soil instability, such as slumped zones extending 100 feet or so along 11-8 the base of the slopes and extensive tilting of trees indicate that at least the upper 10 or 20 feet of th e soil is loosely consolidated and subject to failure on the steep slopes. Proceeding upstream the valley gradually changes in form with the floodplain widening and the slopes becoming far more gentle with no if ~~~significant evidence of slope instability. Depth to bedrock is a matter for conjecture. The presence of a quarry 'I ~ ~~in bedrock high on the right bank in the general vicinity of the dam axis considered farthest downstream (Site 1, Figure 1.1) indicates that I ~ ~~the bedrock surface occurs within the right wall of the valley. There is no evidence, however, to indicate how deep it is at creek level. Similarly, occurrences of Kachemak soils high on the left bank, as indicated by the soil survey (1), suggest that the bedrock surface lies within the left wall along the lower reache's of the valley where the 3 ~~~creek is deeply incised in the upland surface. 11.5 Preliminary Project Arrangement For comparison purposes with Twitter Creek, a reservoir size of 2300 1 ~~~acre-feet has been selected. The project will consist of an approxi- mately 90 ft. high dam, a morning-glory shaft spillway, an emergency auxiliary spillway and a low-level outlet works (Figure 10.3). Normal pool level would be at El. 530. Minimum pool level would be at El. 480. The dam would be an earthfill dam with slopes I on 3. It will have an impervious core constructed of compacted clay-silt-sand and gravel. The upstream shell would be clean sand while the downstream I ~~~shell would be random organic free sand or glacial till. Processed clean sand will be used for filters. V ~~~Because of the erodible foundation, a sheet pile cut-off will be driven 5 ~~~with lengths generally about two-thirds-of the head. The shallow dyke 11-9 part on the left abutment will be protected by an impervious blanket. A pressure relief curtain consisting of 80-foot deep wells spaced at 20 feet will be provided at the dam toe. The morning glory spillway will have a weir crest diameter of 14.5 feet. The vertical shaft will be 5.3 ft. in diameter and will join to a horizontal 7.0-ft. diameter conduit. 11-10 12.0 COMPARISON OF FRITZ AND TWITTER CREEKS 12.1 General Preliminary cost estimates for comparison purposes were prepared for Twitter and Fritz Creek alternatives. These estimates, though not complete, were developed to an equivalent level sufficient for the determination of the most economically attractive alternative. The cost estimate and available water at each site were then compared. This comparison is shown in Table 12.1. 12.2 Twitter Creek Cost Based on the information presented in Section 10, (TWITTER CREEK ALTERNATIVE), a cost estimate was prepared. The estimated cost of construction for Twitter Creek is $18,644,000 (1983 dollars) which will include the cost of the facilities required to deliver the water to Bridge Creek. This will result in a capital investment of almost $13,000 per acre-foot of water yield. 12.3 Fritz Creek Cost Based on the information presented in Section 11, (FRITZ CREEK ALTERNATIVE), a cost estimate was prepared. The estimated cost of construction will be $17,533,000. The 6.5-mile transmission line to Homer will cost approximately $3,089,000. Thus, the total cost will be $20,622,000 excluding treatment facilities. 12-1 TABLE 12.1t TWITTER & FRITZ CREEKS RESERVOIR DATA Twitter Creek Fritz Creek Firm Yield1 1.98 cfs (1.28 MGD) 2.9 cfs (1.87 MGD) Storage Volume 1,500 ac-ft 2,300 ac-ft Capital cost, 1983 $18,644,000 $20,622,000 dollars Yield, ac-ft per year 1433 2100 Capital cost per ac-ft $12,950 $9,820 of yield 160% of monthly flow reserved for instream requirements; yield based upon critical dry period 1950-1952. 12-2 ii This will result in a capital investment of $9,820 per acre-foot of I ~~~~water yield. 12.4 Alternative Selection The capital cost for Twitter Creek includes the cost of delivering the 5, ~~~water to Bridge Creek reservoir but does not include the treatment plant expansion that might eventually be required. The cost of Fritz Creek includes the cost of delivering the water to Homer but does not include the cost of -a new treatment facility. I ~~~The data above suggests that Fritz Creek would be a more attractive alternative than Twitter to augment the Bridge Creek supply. To reiterate, Fritz Creek has 50% more yield and thus would meet future demands over a longer period of time. Secondly, water can be obtained from Fritz Creek at 76% of the cost per acre-foot of that from Twitter Creek. I ~~~Based on the results of the preceding sections, Fritz Creek was selected as the Alternative to pursue. I~~~~~~~~~~~~~1- 13.0 FRITZ CREEK SITE ALTERNATIVES 1 ~~~13.1 General I ~~~This section discusses the selection of various alternative sites on Fritz Creek. Field reconnaissance has indicated that storage dams 3 ~~~could be built nearly everywhere on this creek below Beaver Creek Flats and upstream of a point in the creek where the cross-section narrows I ~~~down. By rejecting wider cross-sections and slide-suspect slopes, the selection was narrowed down to three sites which are shown in Figure 1-1. These sites are identified as Sites 1, 2 and 3. All sites are downstream of Beaver Creek Flats, a habitat for wildlife. Selection of the final plan should consider the environmental undesirability of I ~~~reservoir intrusion on this area. J ~~~~13.2 Topography and Geology I~ ~~~ Adiscussion of the regional geology is found in Section 8. The items of geologic interest to the Fritz Creek Sites, resulting from the I ~~~geological study performed, are found in Section 11.4 13.3 Alternative Site 3 At the farthest upstream location identified as Site 3, there appears to be a greater feasibility for both abutments and the river bed to be underlain with glacial till to considerable depths than on the other sites. This site appears to have distinct geologic advantages for a dam as compared to the other two sites. These advantages are: 1 ~~~~~~~~~~~~~~13-1 a. Wider valley section with less steep slopes, allowing a lower dam and smaller reservoir depth for a given storage capacity, more I ~ ~~~~stable slopes both at the dam and in the reservoir area, greater space for a spillway and its chute and easier access for * ~~~~~construction; * ~~~b. Lesser creek bed gradient which is favorable to dam design, reservoir storage capacity and access; I ~~~C. Greater el-evation of the dam foundation and therefore a greater possibility of founding the dam on glacial till rather than on the more permeable bedrock in the area; and 3 ~~~d. Higher elevation, thus providing greater available head. 13.4 Alternative Site I This site which is located farthest downstream is considered to be the least suitable damsite. Because of steep, marginally stable slopes, reservoir shore failure could occur under fast drawdown conditions. 3 ~~~~Also, the emergency spillway will require deep excavations and exten- sive and expensive use of gabions with stepped chutes. 1 ~~~13.5 Alternative Site 2 p ~~~Site 2 is ranked midway in quality between Sites I and 3. This alter- native mostly avoids possible shore failure of steep, marginally stable 3 ~~~slopes under rapid drawdown conditions. The emergency spillway will require deep excavation. This site will also require a higher dam than j ~~~at Site I for a given size of reservoir. 13-2 SECTION II PRELIMINARY DESIGN AND COST ESTIMATES 14.0 PRELIMINARY COST COMPARISON OF ALL SOURCES U ~~~14.1 General I ~~~In order to generate a cost comparison of the various sources consid- ered, it was necessary to make some general assumptions. It was 3 ~~~assumed that rock excavation would be minimal; that each source would require approximately the same degree of treatment, hence approximately the same cost for treatment plant new construction or existing expan- sion; that contingencies would all be at the same ratio, thus not included in the estimated costs; and that land and easements, if required, would be obtained at a nominal fee., Until a firm design has been undertaken, to try to cost out these types of items tends to be I ~~~~speculative. 3 ~~~.14.2 Ground Water Sources The average well in the Homer area produces <25 gpm. It would take I ~ ~~approximately 60 wells to produce the required water. This number of wells required is in reality academic since their withdrawal rate far I ~~~~exceeds the publi shed recharge rate (300 gpm per U.S. Geological Survey) for the area. If the number of wells developed were close to 3 ~~~the number required, a very substantial operating and maintenance (OWM cost would be incurred due to the number of pumps, electrical control- lers, etc. Without knowing the motor sizes, well depths, well loca- tions with reference to a treatment plant, the O&M costs cannot be reasonably estimated; therefore only the cost of developing wells and treatment plant costs have been estimated. Again, without firm loca- tions of wells, the quantity of transmission main to tie into the existing system cannot be reasonably estimated. 1 ~~~~~~~~~~~~~14-1 Well Development $3,560,000 Treatment Plant(s) 4,000,000 Estimated Basic Cost $7,560,000 Alternative dropped because of insufficient water production. 14.3 Distant Surface Sources Bradley Lake consideration was estimated but not further pursued once the hydroelectric development was shelved. Minimum basic costs without consideration of constructing access roads and furnishing electrical power was estimated as: Transmission Main - on land $22,000,000 - marine 7,390,000 Treatment Plant 2,000,000 Estimated Basic Cost $31,390,000 China Poot Lake was the only distant surface source near enough to realistically qualify for consideration. As previously stated, there -remains the problem of actually withdrawing water because of the lake's location within the State Park. Construction problems are significant due to the depth of the crossing off the end of the Homer Spit. There will be substantial currents to deal with with each change of tide. Construction on the far shore will be expensive if on land, as much of the excavation will be in solid rock. If the on-shore line is installed in the tidal flats, there can be expected to be considerable opposition to construction in the marshlands. Transmission Main - overland $ 4,118,000 - marine 11,220,000 - Homer Spit 5,206,000 Head work at China Poot Lake 500,000 Water treatment 1,500,000 Estimated Basic Cost $22,544,000 14-2 14.4 Reverse Osmosis (Desalination) A desalination plant utilizing the reverse osmosis process has been previously estimated. To this cost must be added the replacement of the line along the Spit. The one very significant cost associated with this alternative is the high annual O&M cost. This process is very energy (power) intensive. R.O. Plant (2 MGD) $14,000,000 Future Expansion (to 3.6 MGD) 8,000,000 Plant Cost 22,000,000 Spit Transmission Main 5,206,000 Estimated Basic Cost $27,206,000 Annual O&M Estimated Cost $ 1,400,000 14.5 Bridge Creek Two options were considered for Bridge Creek as a source of supply: either raising the existing dam or constructing a new dam downstream of -the existing dam. The main problem is that the existing dam was never intended to be raised. In order to do so, one of the tasks would be to raise the inner core. This is an impervious barrier which inhibits seepage through the structure. As a tapering barrier, it would be necessary to add to the core along the front (downstream) face sufficiently to extend the core to a new height. In order to do this, it would be necessary to strip the material off the face of the dam. This renders the dam structurally unsound, unless the reservoir level is lower. This in turn jeopardizes the existing water supply. Therefore, this option was eliminated as being impractical. No cost estimate was made. 14-3 As was previously discussed in Section 9.7, constructing a new dam downstream meant abandoning the existing dam and appurtenances, abandoning the existing pump station, constructing the new dam and appurtenances and constructing a new pump station. Implementing this option would not significantly increase the available water due to instream release rates required by ADF&G. This option was also deemed to be not cost-effective; therefore no estimate was made. 14.6 Twitter Creek The development of Twitter Creek involved construction of a dam, an intake structure and a pump station. The existing treatment plant at the Bridge Creek site would have to be expanded to process the addi- tional flow. The pumps would have to develop over 300 feet of head to pump over Crossman Ridge and on to Bridge Creek. The ADF&G have indi- cated (May 1983 meeting) that any request to dam Twitter Creek would meet with considerable opposition since this creek supports anadromous fish runs. The cost to develop Twitter Creek as a source of supply is: Dam and Pump Station $18,644,000 Expand Water Treatment Plant 1,900,000 Increase Transmittion Main from Existing W.T.P. to Homer 1,300,000 Basic Estimated Cost $21,844,000 14.7 Fritz Creek Fritz Creek was realized to be the most favorable near surface water source based on the ability to supply sufficient water for the 30-year projection. This having been determined, three sites were selected. Analysis of these sites determined that while any of the individual sites would fulfill the requirement, the northerly (most upstream) site would be the most economical. That is- provide the greatest reservoir volume for the least earthwork (dam) volume. Further consideration was 14-4 given to selected reservoir volume sizes which would be dependent upon the final instream release rate imposed by ADF&G. Regardless of the site selected and the reservoir size, a transmission main from the dam to the treatment plant would be required. The treatment plant would be planned to be located just north of East Road near where Fritz Creek intercepts the road. Another transmission main would follow East Road to the end of the existing main near Palmer Creek, west of Kachemak City. Dam (site 3, 2300 Ac.Ft.) $14,767,000 Treatment Plant 1,629,000 Transmission Main 2,935,000 Basic Cost $19,331,000 Dam (4000 Ac.Ft.) $19,255,000 Treatment Plant 1,629,000 Transmission Main 2,935,000 Basic Cost $23,819,000 Dam (5800 Ac.Ft.) $23,611,000 Treatment Plant 1,629,000 Transmission Main 2,935,000 Basic Cost $28,175,000 14-5 15.0 SITE SELECTION 15.1 Basis of Selection In order to evaluate the three sites under consideration, a reservoir size of 2300 acre-ffet has been selected as a basis for comparison. Project layouts were made for each of the three sites. The Direct Construction costs of each arrangement were estimated and are shown in 3 ~~~~Table 9.1. Table 15.1 PROJECT COSTS AT DIFFERENT SITES (1983 Dollars) I ~~~~~~~~~~~SitelI Site 2 Site 3 Total Cost of Dam $23,035,000 $16,568,000 $14,767,000 I ~ ~~~and Other Facilities U ~~~It is evident that the least project cost will be obtained at Site 3. Similar investigations for other reservoir sizes showed that Site 3 I ~ ~~yields the least project cost. In addition to the economic advantages, other geologic advantages have been discussed previously. Unless there 3 ~~~are environmental problems not evident at this time, Site 3 is con- sidered to be the most feasible site at Fritz Creek. I ~~~15.2 Optimum Reservoir Size I ~~~Experience has shown that for any given site, there is a reservoir volume for which the cost, per acre-foot of storage, of constructing a I ~~~~dam is least. At Fritz Creek, environmental considerations limit the incursion of the reservoir towards Beaver Flats. It was shown in Table 11.2 that the maximum reservoir size to meet year 2030 demands is 5800 acre-feet. The lower limit of reservoir size will be 2300 acre-feet, which is the minimum required to store the creek's firm yield. This has been calcu- lated in previous submittals. Thus the reservoir size should be 3 ~~~between 5800 and 2300 acre-feet. For optimization analysis, an inter- mediate size of 4000 acre-feet was also analyzed. The results of the 3 ~~~analysis are shown in Figure 15.1, where it is shown that the optimum size (least cost in $/acre-ft vs. storage in acre-feet) is beyond the 3 ~~~range of sizes being investigated. 15.3 Reservoir Site Selection In practice, the selection of reservoir size may be governed by consid- 3 ~~~erations other than economics. Normally, the instreamn flow require- ments are first determined. Then either one of two factors control the selection. If the yield of the basin is adequate, the reservoir can be sized to meet the demands at a future date, say 40 to 50 years, the design life of the project. If the yield is not adequate, then the reservoir will be sized to match the firm yield of the basin. Since the instream flows are not known at this time, curves (Figure 15.2) 3 ~~~have been developed which will show the reservoir storage requirement to develop the firm yield of the basin for a specified instream flow. 3 ~~~The upper end of- the curve shows the size required to meet year 2030 demands. The first figure is based on Criterion 1, i.e., instream flow which is a percentage of actual flow'. while the second figure is based on Criterion 2, i.e., instream fl ow which is a percentage of mean 15-2 I ~~~mean annual flow. On the same graphs, firm yield corresponding to any given rsrorsize are also shown. With these curves and the I ~ ~~criterion to be used and the instream flow requirements known, the reservoir size can be selected. U~~~~~~~~~~~~~1- 16.0 DESIGN FLOODS 16.1 Spillway Design Flood An estimate of the spillway design flood was made using 18 years of crest-stage data from Fritz Creek collected by the U.S.G.S. Floods on Fritz Creek are generally caused either by snowmelt in May or June or by heavy rainfall associated with an intense frontal system in late summer or early fall. Floods from fall storms may be augmented by melt from an early season snowpack. The simulation of daily flows described in previous submittals showed that the flood of record, which occurred on November 1, 1970, was caused by heavy rainfall on an early and shallow snowpack. -A flood frequency chart is shown in Figure 16.1. The estimated 500-year flood from this analysis is about 570 cfs. A 10,000-year flood is 740 cfs. In this geographic area, estimates of probable maximum precipitation (PMP) are considered to be unreliable and no data exist for transform- ing storm rainfall to flood hydrographs for the small catchments of interest in this study. The most appropriate approach for estimating design floods was thus deemed to be based on extrapolation of frequency curves of recorded events. For design purposes, a service spillway will be provided to pass a 500-year flood and an auxiliary emergency spillway will be added so that the combined capacities will pass-a 10,000-year flood. 16-1 16.2 Construction Design Flood 1 ~~~The construction period flood was estimated using the curve in Figure 16.1. Because overtopping of the cofferdams will cause a delay in I ~ ~~construction, a recurrence interval of I in 10 years was adopted for the construction period flood. I~~~~~~~~~~~~~1- 17.0 PROJECT FEATURES 17.1 Basic Preliminary Design The design presented herein is preliminary. Extensive geotechnical investigations will have to be made prior to final design. A proposed geotechnical program for the next phase is described in Section 22. The plan, section and details of the project features are shown in Figures 17.1 and 17.2. The height of dam will depend on the reservoir volume required which in turn can only be determined after instream flows are firmed up. The reservoir size will be determined from Figure 15.2 as discussed in Section 15. 17.2 Dam It is assumed that no more than 10 feet depth of stripping will be required. The dam embankment shall be constructed using: a. A massive impervious core and some impervious blanket constructed of compacted clay-silt-sand-gravel and cobble mixtures, i.e., of compacted glacial till; b. A minimum amount of compacted clean sand in the upstream shell zone which is subject to drawdown; c. Processed clean, coarse sand, or coarse sand and gravel for an internal drain layer, frost-proof-crest and "rock" toe; 17-1 d. Random organics-free sand or glacial till fill for the downstream * ~~~~~~shellI; and e. Riprap on filter cloth protecting the upstream reservoir slope as I ~ ~~~~well as the dam toe at tailwater. 3 ~~~Except for a shallow, dyke-like part of the dam up on the left abutment which will be protected by an impervious blanket, the main dam will 3 ~~~feature a sheet pile cutoff wall to varying depth. This depth might be 2/3 of the dam head measured vertically down, or 5 times the dam head measured horizontally into the slopes, whichever measure yields the deeper sheet piling. Both the blanket as well as the sheet piling will protect the very erodible foundation (in some places) against internal I ~~~erosion ("piping"). The dam will tentatively have I vertical over 3 horizontal slopes. 17.3 Service Spillway The service spillway will be a morning glory spillway designed to pass 570 cfs, a 500-year flood. The weir will be 14 feet in diameter set at I ~ ~~normal pool level. The spillway shaft will join to an inclined buried 7-foot diameter conduit. The conduit will be steel-lined where it will l - - ~pass under the impervious core and downstream shell of the dam. Flows will be dissipated before being diverted back to the creek. 3 ~~~17.4 Auxiliary Spillway I ~~~The service spillway will be augmented by an open-chute auxiliary spillway on the right bank of the dam. The combined capacity will be 1 ~~~740 cfs, which is equivalent to a 10,000-year flood. 3 ~~~17.5 Low Level Outlet Works 3 ~~~The low level outlet works conduit will serve as a diversion conduit during construction and for releasing flows during operation into the 17-2 river or to the treatment plant. During construction, the lower conduit will be open. When the dam is completed, a low gate at the U ~ ~~portal will be closed and the conduit will be plugged. Because some parts of the foundation may be flexible, the outlet works pipe will be U ~~~placed within a gallery to avoid possible flexing of the pipe as the dam is constructed. 17.6 Construction Materials * ~~~The materials required for dam construction are: I ~~~a. Glacial till - numerous deposits near the dam sites at elevations suitable for downhill hauling; b. Clean sand - beds of moderately indurated sandstone which may be 3 ~~~~~extracted selectively from quarries such as that on the right bank of Fritz Creek arnd one observed on the left bank of Bridge Creek; I ~~~C. Clean coarse sand or coarse sand and gravel -alluvial deposits at Anchor Point and beach deposits on Homer Spit; d. Random fill - beds of moderately indurated sandstone, siltstone 5 ~~~~~and claystone in quarries such as those described in (b), or glacial till as described in (a); and U ~~~e. Riprap and coarse rock for gabion construction - present in scattered deposits along creekbeds in sizes commonly up to 2 ft. I ~ ~~~~in diameter, in beach deposits of Kachemak Bay and available in sizes to about 2 ft. through the processing of glacial drift 3 ~~~~~deposits near the dam sites. 17-3 1 ~~~~~~~18.0 IN-STREAM ANALYSIS AND RESERVOIR SIZING 18.1 Discussion At the outset of this study, the Alaska Department of Fish and Game (ADF&G) stated a general policy of 60% of a stream flow be reserved for I ~ ~~the fisheries habitat. This in turn created a condition where a con- siderable volume (up to one-half if measured against mean annual flow) 3 ~~~of the reservoir was in essence not available for the City's use. In order to satisfy the City's ultimate needs plus the in-stream require- 3 ~~~ment, a reservoir of substantial size was realized. If the in-stream flow was a percentage of the mean annual flow, the I ~ ~~Minimum reservoir was 4900 acre-feet (1.6 billion gallons) of which 2300 acre-feet (750 million gallons) was available to the City. When 'the in-stream flow was measured as a percentage of actual flow, the minimum reservoir size dropped to 2300 acre-feet (750 million gallons) 3 ~~~with 1900 acre-feet (600 million gallons) available to the City. In either instance, using a 60% in-stream flow would not yield the 3400 I ~ ~~acre-feet required to satisfy the City's 2030 peak day demand (over the life of the dam). A meeting was held May 5, 1983, with the City, the I ~ ~~City's engineering consultant and ADF&G to discuss the in-stream flow requirement and the effects of the reservoir on moose wintering 3 ~~~grounds (see Appendix A). At this meeting ADF&G brought out that there were no returning anadromous fish runs in Fritz Creek due to a blockage I ~~~to the fish near the stream's mouth. The only fisheries use of Fritz Creek was an annual (May) release of salmon smolt at the point where 3 ~~~Fritz Creek goes under East Road. - 18-1 The much greater concern was the size and location of the reservoir and its effect in the partial elimination of wintering grounds of moose during periodic extremely severe winters. I ~~~~In order to address these concerns, the reservoir-dam site requirements were reexamined. The maximum day demand is peak domestic demand (dur- 3 ~~~~ing a hot spell) plus the canneries' usage during processing from June to September. At other times the water required is significantly less 3 ~~~with the peak day to average day ratio in the range of 1.70-1.96. Thus the daily average usage could be expected to be in the range of 2.0-2.4 MGD. The projected mean annual flow is 9.88 cubic feet per second (cfs). 3 ~~~The year 2010 maximum day is 6.2 cfs and the 2010 average day is 3.7 cfs. The lowest recorded mean daily flow, which occurred on January 5 ~~~13, 1969, was 0.85 cfs. or 8.5% of the mean annual flow. The second- most low was 1.78 cfs or 18% occurring on April 1, 1972. As can be seen, both low flows occurred during the period of low demand, i.e., cold weather and fish processors not operating. 1 '~~~18.2 Conclusions 3 - ~~The reservoir capacity is based on the maximum day demand for a pro- jected population in the year 2010. The average day demand is 60% of 3 ~~~~the maximum day demand, including processors. The 60% in-stream flow appears to be an arbitrary guideline to serve until additional information is available. This guideline assumes a certain volume of water being available for fish, if no other study is 3 ~~~~undertaken. 3 ~~~A third factor not discussed is that some volume of water needs to be released at all times for aesthetic reasons. 18-2 Once the reservoir is filIled, at most times of the year, the stream flow will exceed the City's demand and water will be spilled anyway. I ~ ~~It is very easy to concentrate on one time period such as the maximum day and forget about the other 364 days. 18.3 Recommendations The dam should be built under a phased construction program. The first phase would be to a pool elevation of 515 feet. This would provide a storage-of 1050 acre-feet. The average daily demand of 2.4 MG equals 662 acre-feet. If the processors' demand of 0.43 MG is included, the I ~~~total becomes 1050 acre-feet. This also gives a 90-day supply of water which should be sufficient to go through the summer months including processing. The dam can be raised to the design pool elevation of 530 feet at some time in the future if the need materializes. 1 ~~~It is further recommended that the in-stream flow be no less than 20%. This will maintain the lower recorded flows while in most instances will be considerably above this percentage. In addition, the City should work out a program with ADF&G to release an increased volume of 5 ~~~~water into Fritz Creek during the period in which salmon smolt are being released. ~~~~~~~~~~~~~~18 19.0 WATER QUALITY 19.1 Objectives of Water Treatment I ~~~The three basic objectives of water treatment are: * ~~~a. Production of water safe for human consumption. b. Production of water appealing to the customer. 3 ~~~C. Production of water using facilities reasonable with respect to capital and operating costs. 3 ~~~In other words, safe and healthy, esthically acceptable, and economical water. A properly designed plant is not a guarantee of safety, how- I ~ ~~ever. Skillful and alert plant operation and attention to the sanitary rquirements of the source of supply and the distribution system are 5 ~~~~equally important. 3 ~~~19.2 Quality of Source-of Supply The type of treatment depends on the quality of the source of supply I ~ ~~and the quality desired in the finished product. Adequate information on the source is thus a prerequisite for design. This includes analy- I ~ ~~sis of the water and the ranges of the various characteristics. Surface waters tend to be variable in quality, contain lower concentra- tions of minerals, to be more highly colored, to be turbid at times, and to contain taste- and odor-producing substances. In order to produce data required on the potential quality of source waters, an ongoing water sampling and an alysis program was established. The program has been in effect in excess of one year, having started in 19-1 July 1982. The results to date are shown in Tables 19.1, 19.2 and 19.3 for the six major parameters measured. In addition, for Bridge Creek, I ~ ~~some of the major parameters are analyzed on a daily basis for both influent (raw) water and for effluent (treated) water. a. Color Color indicates the presence of dissolved foreign substances. Color is pH sensitive with color more intense at high pH values. Color can absorb chlorine and reduce chlorine effectiveness as a disinfectant. Colored water is objectionable in appearance and I ~~~~~causes difficulties in washing clothes, manufacturing foodstuffs, etc. b. Odor Odors generally originate from biological sources such as algae, decaying organic matter, and bacteria] reactions. Most odors are objectionable in nature, unpleasant in certain levels and may, at I ~~~~~the extreme, harbor lethal gases. C. Turbidity Turbidity in water is caused by minute suspended particles of clay, silt, organic and inorganic matter, plankton and other microscopic organisms. Turbidity scatters and absorbs light. Water-borne diseases may be hosted by the particulates causing the turbidity. Chlorination may not be fully effective as a disinfec- tant in the presense of particulate matter, therefore creates the 3 ~~~~~need for very low turbidity for a first-class drinking water source. I ~~~d. Alkalinity I ~~~~~Alkalinity is a measure of hydroxi de, carbonate or bicarbonates 19-2 Table 19.1 SOURCE WATER QUALITY COLOR TURBIDITY Color Units (JTU) Date Bridge Fritz Twitter Bridge Fritz Twitter (State Standard) (15) (5 JTU) 07-19-82 30 25 15 3.4 6.5 1.0 08-26-82 16 27.5 40.8 2.4 3.7 5.1 10-24-82 25 25 20 2.0 1.4 1.1 11-18-82 15 20 - 0.8 1.3 - 12-17-82 25 30 30 0.34 0.95 0.73 02-17-83 30 15 1.6 1.4 04-06-83 100 100 42 38 05-10-83 - 75 - 15 08-25-83 60 35 2.8 1.2 09-15-83 50 40 3.9 4.1 19-3 Table 19.2 SOURCE WATER QUALITY IRON TOTAL DISSOLVED SOLIDS (mg/L) (TDS) (mg/L) Date Bridge Fritz Twitter Bridge Fritz Twitter (State Standard) (0.3 mg/L) (500 mg/L) 07-19-82 0.59 0.34 <0.05 65 92 63 08-26-82 0.47 0.18 1.12 99.7 69.4 95.4 10-24-82 0.1 0.3 0.5 32.5 5.5 5.4 11-18 82 0.17 1.40 68.5 81.5 12-17-82 0.15 0.24 0.72 69 98 89 02-17-83 0.66 0.38 61 94 04-06-83 2.17 2.08 56 74 05-10-83 - 1.00 - 63 08-17-83 1.06 0.69 64 82 09-15-83 0.74 1.09 63 83 19-4 Table 19.3 SOURCE WATER QUALITY ALKALINITY pH (as CaCOq) Date Bridge Fritz Twitter Bridge Fritz Twitter 07-19-82 6.9 6.6 6.7 30 40 26 08-26-82 6.9 6.4 6.6 50 27 37 10-24-82 6.1 6.5 6.4 29 35 26 11-18 82 6.8 7.1 21 32 - 12-17-82 6.7 7.5 6.9 23 43 30 02-17-83 6.2 6.6 23 66 04-06-83 6.4 6.3 17 32' 05-10-83 - 7.2 - 24 08-17-83 7.0 6.9 29 49 09-15-83 6.6 6.4 27 43 19-5 present in solution. This presence relates to the hardness of water. Although "hardness" or "softness" of water is subjective by individual, in general soft water lathers easily and leaves no "ring" in the bathtub. Hard water does not lather well, leaves I ~~~~~hands rough and a "ring" in the tub. Also, hard water leaves deposits in boilers and can be corrosive to certain materials. I ~~~e. Total Dissolved Solids (TDS) I ~~~~~Total dissolved solids are those solids remaining in solution after all the suspended solids have been removed by a filter. TDS I ~ ~~~~can be measured by conductivity or the solution's ability to conduct an electrical current. This in turn is related to the * ~~~~~concentration of ionized substances in the water. 5 ~~~~f. -Iron Iron is generally present in all normal waters to some extent, but I ~ ~~~~is not normally a public health problem, merely a nuisance. Iro'n hydroxide stains clothing and porcelains. Iron is also a food 5 ~~~~~source for so-called iron bacteria and its associated slime growths, taste and odor problems. I~~~~~~~~~~~~~1- 20.0 WATER TREATMENT PLANT 20.1 General The characteristics of the Fritz Creek water closely resemble that of Bridge Creek. This has been verified by approximately one year of monthly sampling of both raw water sources. Based on this similarity the decision was made to design a plant similar to the existing plant on Bridge Creek. This decision serves two purposes. First, we are using a proven treatment process and secondly, it will not be necessary to retrain or maintain operators for two different processes. In addi- tion, annual O&M'costs should be less as there will be duplicated equipment and chemicals. 20.2 Design Criteria 5 Units 6 Units (Future) Net Flow Rates Average Maximum Average Maximum 2 MGD 2.8 MGD 3 MGD 4 MGD 1400 GPM 1960 GPM 2211 GPM 2800 GPM Filter Data Diameter 10'-0" Overall Height 10'-7" Filter Area 78.5 sq.ft. Filter Rates 5 Units - 3.68 GPM/ft2 avg. - 5.1 GPM/ft2 max. 6 Units - 4.7 GPM/ft2 avg. - 6.2 GPM/ft2 max. Media Design Graded gravel - 16 in. High density support gravel - 3 in MF 32 Mixed media - 30" MF 186 20-1 Filter Wash Backwash Rate 1413 GPM @ 45' TDH (18 GPM/ft2) Surface Wash Rate 50 GPM @ 60 psi Cycle 10-15 min. (each unit) Washwater Useage 11,775 gal/cycle/unit Chemical Treatment Max. Avg. Soln. Dose Feed Consumption lb/day Dose Rate Rate Rate Average Maximum Chemical mg/L mg/L Solution (GPH) (2 MGD) (2.8 MGD) Alum 3-30 20 15% 20 332 464.8 Soda Ash 1.5-15 10 10% 20 166 232.4 Polymer 0.1-2 0.5 0.25% 3 8.3 11.62 SHMP 1-10 5 20% 3 83 116.2 Chlorination Prechlorination dosage 0.3 to 3.0 mg/L Average dose 2 mg/L Consumption average 33.6 lb/day max. @ 2.0 MGD Injector water 8 GPM @ 30 psi Postchlorination dosage 0.5 to 4 mg/L Average dose 2 mg/L Consumption average 33.6 lb/day, max 93.3 lb/day Injector water 20 GPM @ 10 psi Chlorine Withdrawal Average 67.2 lb/day Maximum 100.8 lb/day Cylinders 4 - 150 lb in service (4 max days) 15 - 150 lb in reserve and transit (31 avg. days) Sludge Production Average plant rate 2.0 MGD Suspended solids in raw water 10 mg/L 20-2 Average Sludge Production Daily Annual Weight 498 181,770 lb Vol. @ 1% (settling ponds) 800 292,000 cu.ft. Vol. @ 5% (drained sludge) 16,000 cu.ft. Vol. @ 17% (frozen sludge) 4,705 cu.ft. Backwash Settling Ponds Backwash storage volumes to be determined at a later date based on soil analysis at the project site. 20.3 Description of Operation The proposed water treatment plant for Homer, Alaska, is a direct filtration plant with pressure filters, chemical feed, pumps, valves, instrumentation and controls as described on the attached flow dia- gram, Figure 20.1 Raw water will be delivered to the plant by gravity. Provision is made to chlorinate the raw water pipeline if algae is present. Raw water pumps are provided to boost the incoming pressure during periods of high flow. It is estimated that 50 feet of head is required to push water through the plant under maximum conditions. An additional 16-18 feet of head is required to fill the storage tank. When the reservoir is full and the demand is low, the raw water pumps will not be used. An influent flow meter will be provided to monitor the plant flow and establish a set point for the chemical feeders. The chemical feed equipment consists of gaseous chlorine (Cl2) for disinfection, aluminum sulphate (alum) for coagulation, soda ash for pH adjustment, polyelectrolyte for filter-conditioning and sodium hexa- metaphosphate (SHMP) for corrosion control. Chemical feed rates are set manually as determined by the flow rate, jar tests, and effluent 20-3 water quality. A static mixer insures the complete distribution of chemicals in the raw water. Filtration is provided by five 10-foot-diameter pressure tanks (plus one future tank) designed to deliver an average flow of 2 MGD with peaks to 2.8 MGD (4 MGD future). Each filter will be complete with filter media, underdrains, surface wash arms, mainways, insulation, automatic control valves, and a turbidimeter. The filtration system will be operated in declining rate with a common differential pressure switch/indicator and effluent rate control valve. A 500,000-gallon tank will be installed to provide water for backwash and surface wash purposes as well as storage for peak flow conditions. Level controls in this tank will start and stop the plant. Backwash and surface wash pumps will be provided to clean the filters as they become dirty. The resulting backwash waste will be directed outside the building to two lagoons. The lagoons will be operated -alternately to allow dewatering and sludge disposal of the offline unit. The amount of treated water actually delivered to the distribution system is monitored by a final effluent flow meter. A recorder in the plant control panel will provide a permanent record. A programmable controller will provide the logic hardware required to operate the plant. The controls will provide for automatic operation with manual override. Recorders will provide a permanent record of the amount of water treated and its turbidity. 20-4 20.4 Estimated Power Requirements Equipment Quantity Voltage Amps KVA Heater 2* 115 6 1.38 Dehumidifiers 2 230 30 13.8 Wall Heaters 6 230 10 13.8 B/W Pump 460 26 12 S/W Pump 460 10 4.6 Cl2 Booster 230 8** 1.84 Controls 10 115 10 11.5 Lighting 230 25** 5.75 Chemical Pumps 4 230 5 4.60 Compressor 230 10 2.3 Raw Pumps 2 460 32.8 15.09 86.66 KVA * Assumes gas heaters ** Estimated 20-5 21.0 TRANSMISSION MAIN The transmission main can be divided up into two distinct packages: the section from the dam to the water treatment plant and that section from the treatment plant to the end of the existing line at Kachemak. 1 ~~~21.1 Design The optimum transmission main size to deliver the maximum day flow of 4.0 MGD (2770 gpm) with acceptable line friction losses is 18 inches in diameter. However, with the addition of storage dt the treatment plant and a second 0.5 MG storage tank in the vicinity of the termination of this line near Kachemak City, the line size can be reduced to a 16-inch diameter. In this preliminary study we have assumed the latter line -size. 21.2 Location and Siting The proposed site of the Fritz Creek reservoir requires that the water I ~ ~~main to the treatment plant be laid next to the existing creek, preferably on the west side. This will make it necessary to construct I ~ ~~a road next to the existing creek for construction, and future access to the water main. The length of this road will be approximately 7600 feet. All of this section will be required to be on easements. The location of the proposed water treatment plant is critical. It I ~ ~~must be at an elevation of 425 to 450 feet to provide by gravity the required design flow for the year 2010- The final siting cannot be completed until a parcel of land is obt'ained. 21-1 Wherever the water treatment plant is located, a 500,000-gallon storage tank must be provided to handle peak water demand as well as to provide storage for backwashing the filters. The tank should contain a level control for shutting the plant off when the storage tank is full and for turning the plant on at some pre-determined low water level. The run of transmission main from the treatment plant to Kachemak will be entirely within public right-of-way. The line would preferably be located on the northerly (uphill) side of East Road. In the vicinity of where the new water transmission main will connect with the existing 12-inch diameter main, a water storage tank must be provided to equalize the incoming pressure from the transmission main with the elev. 340 pressure zone to which it will connect. This connection will require a backflow check valve chamber on the downstream side of the storage tank to prevent the possibility of water in the distribution system from backing up into the tank. Future consideration should be given to construction of a 12-inch main -from the terminus of this 16-inch line, parallel to the existing 12-inch main through Kachemak to Miller's Landing, then along Kachemak Bay Drive to the end of the existing 12-inch line at the airport. This would provide a looped system and a more direct feed to the Spit. 21.3 Material Transmission main piping should be ductile iron with consideration given to use of mechanical joints on the steeper runs from the dam site to the treatment plant. 21.4 Depth of Bury All piping shall have a minimum depth of bury of seven feet. Native material should be acceptable for backfill with the use of ductile iron pipe. 21-2 21.5 Hydrants Hydrants have been spotted on the transmission main from the treatment plant to Kachemak City. The hydrants were located in the vicinity of existing structures. Provision for additional future hydrants has been made through the installation of capped tees at intervals of approxi- mately 500 feet. 21-3 22.0 CONSTRUCTION COST ESTIMATES 22.1 General The construction cost estimates are based on the arrangement described in Section 11. These cost estimates are based on 1983 price levels. Since the reservoir size cannot be established until instream flows are firmed up, three cost estimates were made for reservoir sizes 2300, 4000 and 5800 acre-feet. A cost curve is also developed in Figure 22.1 to allow interpolation of costs for intermediate reservoir volumes. Quantities were established for major construction features to which unit prices were applied. Unit prices were derived using labor and equipment rental rates in Alaska. An overhead factor of 0.40 was applied to direct costs to obtain bid unit prices. The following assumptions were made in deriving unit prices: a. Till material is available within one mile of the dam site; b. Pit run sand can be obtained on the right bank of Fritz Creek; c. Filters will be trucked from Anchor Point, about 16 miles away; d. Random fill can be obtained from excavation in the vicinity; e. Riprap and coarse rock for gabion construction will be available from observed beach deposits at Kachemak Bay; and, f. Redi-mix can be purchased local-ly. 22-1 It was also assumed that no campsite will be constructed and the labor force will be located at Homer. Mobilization and demobilization are included in the unit prices. I ~~~The estimated construction cost was prepared with the assistance of Diversified Engineers and Constructions, Inc., a professional cost 5' ~~~estimating firm with considerable Alaskan experience. 22.2 Basis of Costs a. Direct Construction Costs This cost includes the total of all costs directly chargeable to 1 ~~~~~the construction of the project and in essence represents a contractor's bid. b. Contingencies I ~~~~~To allow for unforeseen difficulties during construction, uncer- tainties due to lack of sub-surface information and items not I ~~~~~reflected in the estimate, an allowance of 20% for contingencies was applied to the Direct Construction Cost. C. Engineering and Owner Administration U ~~~~~The Engineering and Owner Administration costs are based on actual experience with costs for similar work. The item includes all I ~ ~~~~preliminary engineering work; project feasibility and environ- mental studies; field investigation; processing of required * ~~~~~permits and licenses; final design and preparation of construction contract documents; inspection of construction; and Owner Adminis- tration. An allowance of 13% of the sum of the Direct Construc- tion Cost plus Contingencies is considered a reasonable estimate * ~~~~~for this item. 22-2 U ~~~d. Total Construction Cost I ~~~~~The total construction cost is the sum of the Direct Construction Costs, Contingnecies, and Engineering and Owner Administration. e. Interest During Construction U ~~~~~No allowance for interest during construction is included in the estimates but should be included in calculating the total capital requirements. I ~~~f. Escalation As discussed above, the Direct Construction Costs are based on a 1983 price level. The cost should be escalated to the date at j ~~~~~which bids are to be called. 1 ~~~22.3 Construction Cost Estimates 1 .~~~A cost estimate sunmmary is shown in Table 22.1 and the detailed Direct Construction Cost estimates are included in Appendix A. I~~~~~~~~~~~~~2- Table 22.1 COST ESTIMATE A. SUMMARY - SECTION 1 Transmission Main $2,935,400 Site Improvements 185,850 Water Treatment Plant 1,443,234 Subtotal $ 4,564,484 B. SUMMARY - SECTION 2, Page 12.5 Dam and Appurtenances for: 2300 Ac-ft Reservoir $14,767,000 4000 Ac-ft Reservoir 19,255,000 5800 Ac-ft Reservoir 23,611,000 C. ENGINEERING DESIGN $ 172,200 D. GEOTECHNICAL SURVEY AT DAM $ 73,000 E. CONSTRUCTION MANAGEMENT & INSPECTION (PART-TIME) $ 79,200 22-4 23.0 PROJECT IMPLEMENTATION U ~~~23.1 Schedule I ~~~Previous studies have shown that under adverse conditions, the yield in Bridge Creek reservoir will barely meet probable water demands in 1985. I ~~~Consequently, a schedule was developed to complete the project in the earliest possible time. The proposed schedule is shown in Figure 23.1. * ~~~The feasibility studies and the report are scheduled to be finished by June 1983. It is assumed that financing negotiations will be initiated soon after. Land acquisition must also start in 1983 so that construc-. tion can begin in the spring of 1984 and be finished in the latter part of 1985. Delay in financing negotiations or land acquisition will cause the schedule to slip. .Geotechnical explorations should be undertaken in the summer of 1983, to be followed by design. The construction period will require two I ~~~years. The earliest that the project will be completed will be the latter part of 1985. The reservoir will be filled by June of 1986. I ~~~23.2 Proposed Geotechnical Investigations It is proposed to perform the following geotechnical investigations in the next phase of the work. The program recommended is as follows: a. Seven drill holes varying in depth from 50 feet to 100 feet for an approximate total of 550 feet. The locations of those holes are: two 100-foot holes each at the top of both abutments, two 75-foot holes halfway down the abutments and one 100-foot deep and two 23-1 U ~~~~~50-foot deep holes at the valley bottoms. Of these the first five shall be at or near the dam axis, while the last two shall be U ~ ~~~~located near the upstream and downstream toe of the dam. The holes shall be logged and sampled. Standard blow counts shall be taken at, say, 5-foot intervals and in-situ permeability observa- tions shall be made. The drilling will require a suitable rotary drill rig, casing, sampling tools including a 2-mil diameter "standard" split spoon and 140-lb. hammer, parker, water pump and * ~~~~~sample containers; b. The investigation might have to be augmented by seismic surveys: C. In-situ measurements of stress-strain and strength behavior of the * ~~~~~foundation soils in their undisturbed state are also proposed to be made by pressure-meter. For these purposes, special equipment and special crew shall be brought to the site to make the neces- sary tests in the boreholes; and, I d~~~ At borrow areas, test pits shall be excavated. Samples obtained from the pits will require simple laboratory identification and 3 ~~~~~compaction testing. A "budget" estimate for the proposed work outlined above was obtained fromtheAnchorage, AK office of Shannon and Wilson (see Appendix B). I ~ ~~Their estimated cost of the work was $74,000 for a track-mounted operation, or $123,000 if it is necessary to use a helicopter-assisted 3 ~~~~operation. 23-2 24.0 CONCLUSIONS AND RECOMMENDATIONS 24.1 Conclusions. I ~~~Based on the studies made, it is concluded that: U ~~~a. The expected yield from the existing reservoir in Bridge Creek during low flow periods is estimated to be significantly less than was previously estimated by others. Compared to the 1982 demand of 0.56 MGD, the yield of Bridge Creek is close to being reached. U ~~~b. Bridge Creek dam was not originally designed to be raised. Structural and hydraulic considerations indicate that raising the darn is not feasible. 3 c. ~~~Fritz Creek is the most viable alternative for supplying demands in the future. It has 50% more yield than Twitter and consequent- 3 ~~~~~ly can meet future demands over a longer period. Secondly, the cost per acre-foot of yield at Fritz Creek is 76% of that at 3 ~~~~~Twitter. d. Instream flows have a significant impact on water yield. Discus- sions should be held with the Alaska Department of Fish and Game to apprise them of the impact of their instream flow requirements * ~~~~~to water yield. 3 ~~~e. A dam can be built at Fritz Creek. The best site would be Alternative Site 3 provided that there are no environmental 3 ~~~~~constraints; 24-1 f. The reservoir size can only be determined after instream flows are firmed up. It should be between 2300 and 5800 acre-feet; g. The spillway design flood will be 570 cfs, a 500-year flood. Provisions to handle extreme floods (10,000-year recurrence interval) should be provided. The construction design flood will be 260 cfs, a 10-year flood; h. The project will consist of an earth-fill dam about 100 feet high with 1 on 3 slopes, a glacial till core and sand and random fill shells. The service spillway will be a morning glory spillway while the auxiliary spillway will be an open chute type. The low level outlet work pipe will be a steel pipe within a gallery under the dam; i. Total construction costs are about $2,200,000 per acre-foot of yield (1983 dollars); costs will range between $14,800,000 and $23,600,000 depending upon the size of the reservoir; and j. Geotechnical explorations will be required prior to design. 24.2 Recommendations It is recommended that geotechnical investigations be undertaken in the summer/fall of 1983 so that construction can proceed and the project will be completed in time to meet 1986 demands. Land acquisition and financing negotiations must be initiated immediately since these are critical tasks for project implementation. Based on Item (a) above, it is recommended that the City actively pursue immediately plans for the development of Fritz Creek and/or evaluate means by which to keep demands from growing rapidly. 24-2 SECTION III PROJECT FINANCING AND IMPACT ANALYSIS 25.0 PROJECT ECONOMIC AND FINANCIAL ANALYSIS U ~~~25.1 General Financing I ~~~Previous chapters have examined the technical, environmental and cost aspects for the alternative means of expanding Homer's water source capacity. The purpose of this chapter is to analyze the effects of pursuing any of the three alternatives involving development of a dam, 3 ~~~reservoir and water treatment plant on Fritz Creek. A number of previous studies have developed information which is useful I ~ ~~in examining economic aspects of the project. Recent reports which can be utilized include a water and sewer rate study completed in 1983, a I ~ ~~water plan update completed in 1982 and a comprehensive plan update completed in 1983. The comprehensive plan update contains projections of population and 3 ~~~economic growth in Homer and surrounding areas for the next several decades. In general, the entire Homer area is projected to continue to grow at a rapid pace for the next decade, with somewhat slower growth during the following two decades. I ~~~In addition, the water plan update provides that service will be extended to additional areas of the city, increasing the fraction of the city's population served from the present 60 percent to 90 percent by the year 2010. The result of rapid population growth, coupled with extending service to increasingly large fractions of the community, would be a dramatic rise in annual water consumption for most uses. The sole exception to this is in the'area of fish processing, where 25-1 U ~~~future growth depends on economic and biological factors well outside of the control of Homer. Table 25.1 summarizes these figures. Developing the new water improvement will have major impacts on the finances of Homer's water utility. As of this writing, the City is currently considering rate increases averaging 39 percent simply to * ~~~bring the utility's operations to a point where revenues are sufficient to cover direct and indirect costs of service. Future increases averaging 6 percent per year will also be needed to continue to cover direct and indirect costs through Fiscal Year 1989 without allowing for major capital improvements such as the water supply expansion (Brown I ~~~and Caldwell, 1983). * ~~~When the costs of constructing and operating the water supply expansion are figured into the system's operations, it becomes obvious that 3 ~~~further substantial rate increases would be needed to pay for the project. Without allowing for outside financing (for example, Legisla- tive grants from the State), financing the project by incurring long- I ~ ~~term debt would require rate increases totalling from four to eight times rates projected for Fiscal Year 1987 by Brown and Caldwell -(1983). For the smallest dam and reservoir alternative, average FY 1987 charges for residential customers would rise from $18.28 to 3 ~~~$104.83 per month. For the medium and high cost alternatives, monthly residential charges would be $125.07 and $144.43, respectively. In terms of percentages, these represent respective increases of 474, 584 and 690 percent, respectively. I ~~~If areas adjacent to the transmission line are also served, some savings could be realized by spreading the capital costs over a larger 3 ~~~number of customers. Average increases in monthly charges, however, would nevertheless be substantial. Increases over average monthly charges (based on rate projections prepared by Brown and Caldwell1 (1983)) would be 407, 500 and 590 percent for the low, medium and high cost alternatives, respectively. Average monthly charges per residen- tial customer for Fiscal Year 1987 would increase from the projected 25-2 Table 25.1 EXISTING AND PROJECTED WATER USAGE AND CUSTOMERS Fiscal Years Ending 1983 to 2006 Fiscal Years Ending 1983 1987 2006 Number of Customers Residential 550 818 3,083 Commercial 109 159 600 Public Authority 20 29 111 Homer Spit 25 37 116 Total 713 1,043 3,911 Average Total Water Usage per Customer per Year (MG) Residential 0.07 0.07 0.07 Commercial 0.26 0.26 0.26 Public Authority 0.54 0.54 0.54 Homer spit 3.07 3.07 3.07 Total Water Usage (MG) Residential 39.13 60.85 229.37 Commercial 28.34 40.94 154.51 Public Authority 10.80 15.73 60.29 Homer Spit 76.75 113.65 357.51 Total 155.02 231.17 801.67 Source: Olympic Associates Company, based on data from CH2M Hill (1982) and Brown and Caldwell (1983). 25-3 $18.28 to $92.64, $109.75 and $126.10 for the three water supply expansion alternatives. Table 25.2 summarizes these figures. If State and Federal grant financing were to be obtained, it would be 3 ~~~possible to avoid many of the rate increases; however, increased opera- ting costs would still require an increase over Fiscal Year 1987 rates. 3 ~~~For example, if grants could be secured to pay for 90 percent of the project cost and only City of Homer residents were served, Fiscal Year 1987 rates would still need to increase by 46 to 80 percent over I ~ ~~currently projected rates for that year. Average monthly charges for residential customers would increase from the projected $18.28 to 3 ~~~$27.30, $29.33 and $31.26 for the three water supply expansion alterna- tives. If achmakCity and other areas adjacent to the transmission line were seredtherequired rate increase would be about one quarter less, wihprojected Fiscal Year 1987 average monthly residential charges of $24.98, $26.69 and $28.33 for the three expansion alternatives. Table I~ ~ ~ ~2. summnarizes these figures. Prospects of obtaining this level of aid are discussed in the following section. 25.2 Financing Sources 'Three different approaches can be taken to financing a capital project 3 ~~~such as the water improvement. They have been described as: a. Pay as you acquire, 3 ~~~~~b. Pay as you use, and C. Get someone else to pay (Faas, et al., 1982). These approaches are described separately in the sections below. 25-4 Table 25.2 PROJECTED RATE IMPACTS OF WATER SUPPLY EXPANSION ALTERNATIVES ASSUMING NO GRANT FINANCING Average Average Monthly Construction Projected Increase Charge for Cost No. of Over Residential Cost Range (Millions Customers FY 1987 Customers Alternative of 1983 $) FY 1987 Rates FY 1987 Service provided to City of Homer customers only (No Action) na 1,043 na $ 18.28 I1 $19.45 1,043 474% $104.83 2 $24.00 1,043 584% $125.07 3 $28.35 1,043 690% $144.43 Service provided to all customers adjacent to transmission line 1 $20.00 1,572 407% $ 92.64 2 $24.55 1,572 500% $109.75 3 $28.90 1,572 590% $126.10 Source: Olympic Associates Company 25-5 Table 25.3 PROJECTED IMPACTS OF WATER SUPPLY EXPANSION ALTERNATIVES ASSUMING 90 PERCENT GRANT FINANCING Average Average Monthly Construction Projected Increase Charge for Cost No. of Over Residential Cost Range (Millions Customers FY 1987 Customers Alternative of 1983 $) FY 1987 Rates FY 1987 Service provided to City of Homer customers only (No Action) na 1,043 na $18.28 I1 $19.45 1,043 49% $27.30 2 $24.00 1,043 60% $29.33 3 $28.35 1,043 71% $31.26 Service provided to all customers adjacent to transmission line 1 $20.00 1,572 37% $24.98 2 $24.55 1,572 46% $26.69 3 $28.90 1,572 55% $28.33 Source: Olympic Associates Company 25-6 a. Pay as You Acquire Approach I ~~~~Under the Pay as You Acquire approach, ca sh reserves and accumulated reserve funds are used to pay for the project. This approach saves interest cost (which can equal the construction cost over the life of the project), helps preserve borrowing capacity for unforeseen major 3 ~~~outlays, avoids the inconvenience associated with planning and market- ing bonds, and helps foster favorable bond ratings on the occasions 3 ~~~when long-term financing is used. The primary disadvantage of this method is that current users pay an additional charge to cover the cost of improvements to be used in the future. Essentially, this amounts to a subsidy from present to future 3 ~~~residents, and is often considered an inequitable method of financing a project. In addition, unless the City were to exercise extraordinary 3 ~~~fiscal restraint, have relatively modest capital projects needs AND have access to a large tax base, Pay as You Acquire would not be suited 3 ~~~to finance the project alone unless combined with other approaches. b. Pay as You Use Approach Under the Pay as You Use approach, capital projects are paid for by borrowing against future revenues with bonds, government or private loans or other forms of debt. Extending the financing avoids the large fluctuations in budgets which large capital projects can cause, and it may be cheaper to borrow and pay today's price rather than wait and pay tomorrow's price when inflation is driving up construction costs. Many believe that a long life asset should be paid for by its users during its normal life, rather than all at once by those who may or may not have the use of it for its full life, and that Pay as You Acquire 3 ~~~amounts to an unwarranted subsidy from existing to future users. Higher interest costs may also be offset by spreading the costs over a larger number of users in a growing p'opu lation, and allows costs to be better synchronized with benefits (Faas, et al., 1982). 25-7 Two basic types of bonds are most frequently used by local governments. General obligation bonds pledge the taxing power and full faith and I ~ ~~credit of the City to meeting the required payments on the bonds. Under state law, general obligation financing must be approved by the I ~~~voters, particularly for a project of this size. 3 ~~~However, general obligation bond financing has limited potential for this type of project. The City's current policy is that its net general obligation debt may not exceed eight percent of total assessed property value (Pacific Rim Planners and Engineers, Olympic Associates Company, 1983). At the end of Fiscal Year 1982, the City had total I ~ ~~assessed valuaton of $125 million, and a net general obligation bonded debt of $1.8 million, representing 1.5 percent of total valuation. Therefore, 6.5 percent of total valuation, or $8.2 million, is approxi- 3 ~~~mately the maximum additional general obligation debt which can be incurred for all projects at the present time. Even with projected increases in assessed valuation and no new general obligation debt, the I ~ ~~maximum general obligation debt capacity is likely to be no more than $12.0 million by Fiscal Year 1987. Limited liability or revenue bonds are those to which the income from a 3 ~~~public enterprise (in this instance, the City's Water Utility) is pledged toward repayment of the debt, but are not backed by the unlimited taxing power and the full faith and credit of the City (Faas, et al., 1982). For example, Homer has used revenue bonds to fund some previous water system improvements, and has pledged water system * ~~~revenues towards their repayment. 3 ~~~There is no fixed limit in terms of debt capacity for revenue bonds except for the underlying feasibility and creditworthiness of the 3 ~~~project. The financing package supplied to lenders must be accompanied by market studies, rate studies and other documentation to support the project. In addition, convenants or'restrictions are typically I ~~~included in the bond agreements which stipulate that sufficient 25-8 revenues be maintained for the enterprise to cover operating costs and 3 ~~~debt service (exclusive of depreciation) plus allow a substantial cushion to protect for the unexpected. Thus, charges need to be set higher than for general obligation financing in order to simply meet I ~ ~~the lending requirements. In addition, since less security is offered to lenders, revenue bond financing often involves interest rates of one * ~~~or more percentage points higher than general obligation financing. 5 ~~~Private notes or government loans are alternatives to bond financing within the Pay as You Go approach. Included among these are short-term notes issued by local banks or statewide banking establishments, and I ~ ~~low interest loans from State and Federal agencies (Faas, et al., 1982). For example, Federal Coastal Energy Impact loans are available 3 ~~~through the Alaska Department of Community and Regional Affairs to commiunities impacted by outer continental shelf energy development. 5 ~~~The loans offer a low interest rate, and the principal may be forgiven if the energy development the project was designed to serve does not 3 ~~~materialize. A third type of device for Pay as You Go financing is the lease purchase arrangement. A private developer builds the project to the specifications of the agency, and leases it to the agency for a monthly 5 ~~~or annual rental. At the end of the lease period, title to the facil- ity can be conveyed without any further payments. While this circum- 3 ~~~vents debt limits and the need to call special elections, it is costly and is not well suited to the size and nature of the water project. C. Get Someone Else to Pay Approach Under the Get Someone Else to Pay approach, responsibility is shifted 5 ~~~to other jurisdictions, who in turn must decide whether to use the Pay as you Acquire or the Pay as you Use approach to-cover the cost of the 3 ~~~project. For example, private developers may be forced, through subdivision or zoning ordinances, to pay for both on- and off-site 25-9 I ~~~capital project costs attributable to their developments. Property owners may be charged for street or utility improvements benefiting their property through the use of special assessment bonds (Faas, et al., 1982). More important to the water project, if more than one jurisdiction is 3 ~~~served, all benefiting jurisdictions can jointly finance the project. Or, if appropriate jurisdictions do not exist (such as the unincorpo- rated areas along East End Road who might be served by the project), new jurisdictions such as a water service area might need to be created to pay for the project. The other important category of this type of financing is grants-in-aid from other governments. State and Federal grants have been the largest source of financing for capital projects in the City of Homer, and will 3 ~~~continue to be an important source in the future. The major source of grant financing currently is direct grants by the Alaska State Legislature. Funding by this means depends in part on the priority placed on the project by the community, and on the effort by 3 ~~~~the cormmunity to secure state funding. Oil revenues, which constitute the major source of funds for the State, are forecast to generally 3 ~~~decline over the next decade, so it will likely be difficult to secure funding for the entire project. The project will be aided, though, by the fact that it would contribute to the economic growth of the region and the state, which has been a consistent funding priority of both the Administration and the Legislature. 25.3 Financing Prospects Because of the sheer size of the project, it is likely that a combina- tion of approaches will be needed to finance the project. Clearly, current paying users of the system cannot shoulder more than a small fraction of the cost of the projec t Without raising serious questions of inequities between current paying users and both those who use the 25-10 U ~~~~system -now but do not pay for it (i.e., those who haul water) and 3 ~~~~future paying users. Financing will probably need to come from a combination of State grants I ~~~and long-term debt. Additional users will need to be brought into the system to help shoulder the cost of increased capacity, as well as to 3 ~~~improve the economic justification for State grant funding. Some general obligation debt financing could be used to keep interest costs low, but due to the limited debt capacity, revenue bond financing will probably be in order. I ~~~Both legal counsel and bond counsel should be employed to explore the specific legal and financial mechanisms which could be employed. In addition, market studies ought to be conducted prior to obligating the financing to determine whether users would in fact be willing to shoulder, the additional costs of expanding the capacity, or would prefer other devices to limit growth in demand (such as higher user fees, voluntary conservation programs or moratoriums on new hookups) to delay the time at which the new water source will be needed. I~~~~~~~~~~~~~~51 26.0 ENVIRONMENTAL ASSESSMENT 26.1 Introduction I ~~~The purpose of this study is to provide the City of Homer with an addi- tional source of water supply. To this end alternatives were evaluated 1 ~~~~and a dam site on Fritz Creek was determined to be the best solution. 3 ~~~The proposed dam will be of earthfill construction basically using on-site materials. The dam will form a reservoir approximately 100 3 ~~~~acres in size. In conjunction with the dam, a water treatment plant will be construc- I ~ ~~ted. This plant will function similar to the existing plant on Bridge Creek. The tentative location for the treatment plant will be about a mile downstream of the dam and one-half mile upstream from East Road. The treated water will be carried to the end of the existing line near 5 ~~~~Kachemak City through approximately 30,000 feet of water transmission main. U ~~~The impact of this project will be the loss of a part of the moose wintering grounds used during extreme winters, an-occasional reduction 3 ~~~~in the stream flow in Fritz Creek and excavation of material to be utilized in the dam construction. This environmental analysis has been forwarded to and reviewed by the 3 ~~~Department of Natural Resources. Their comments are included as Appendix B. 26-1 26.2 Summary of Proposed Action General The dam design discussed here is preliminary. Extensive geotechnical investigations will be required prior to final design. The height of the dam will depend on the required reservoir volume which can only be determined after instream flows are firmed up. Dam and Reservoir 1. Dam Construction It is assumed that no more than 10 feet depth of stripping will be required. The dam embankment shall be constructed using: a. A massive impervious core and some impervious blanket material constructed of compacted clay-silt-sand-gravel and cobble mixtures, i.e., of compacted glacial till; b. A minimum amount of compacted clean sand in the upstream shell zone which is subject to drawdown; c. Processed clean, coarse sand, or coarse sand and gravel for an internal drain layer, frost-proof crest and "rock" toe; d. Random organics-free sand or glacial till fill for the down- stream shell; and e. Riprap on filter cloth protecting the upstream reservoir slope as well as the dam toe at tailwater. Except for a shallow, dike-like part of the dam up on the left abutment which will be protected by an impervious blanket, the main dam will feature a sheet pile cutoff wall to varying depths. This depth might be 2/3 of the dam head measured vertically down, or 5 times the dam head measured horizontally into the slopes, whichever measure yields the deeper sheet piling. Both the blanket as well as the sheet piling will protect the very erodible foundation (in some places) against internal 26-2 U ~~~erosion ("piping"). The dam will tentatively have I vertical over 3 horizontal slopes. Figure V-i shows a typicl darn section. 2. Service Spillway The service spillway will be a morning glory spillway designed to pass 570 cfs, a 500-year flood. The weir will be 14 feet in diameter set at normal pool level. The spillway shaft will join to an inclined buried 7-foot diameter conduit. The conduit will be steel-lined where it will pass under the impervious core and downstream face of the dam. Flows will be dissipated before being diverted back to the creek. 3. Auxiliary Spillway The service spillway will be augmented by an open-chute auxiliary spill- way on one side of the dam. The combined capacity will be 740 cfs, which is equivalent to a 10,000-year flood. 1 ~~~4. Low Level Outlet Works The low level outlet works conduit will serve as a diversion conduit during construction and for releasing flows during operation into the 3 ~~~creek or to the treatment plant. During construction, the lower con- duit will be open. When the dam is completed, a low gate at the portal will be closed and the conduit will be plugged. Because some parts of the foundation may be flexible, the outlet-works pipe will be placed within a gallery to avoid possible flexing of the pipe as the dam is 3 ~~~constructed. � ~~~5. Construction Materials Required 3 ~~~The materials required for dam construction are: a. Glacial Till - Numerous deposit s near the dam sites at I ~~~~~~elevations suitable for downhill hauling. 26-3 b. Clean Sand - Beds of moderately indurated sandstone which may be extracted selectively from quarries; such as that on the right bank of Fritz Creek and one observed on the left bank of Bridge Creek. c. Clean Coarse Sand or Coarse Sand and Gravel - Alluvial deposits at Anchor Point and beach deposits on Homer Spit. d. Random Fill - Beds of moderately indurated sandstone, siltstone, and claystone in quarries such as those described in (2) or glacial till as described in (1). e. Riprap and Coarse Rock for Gabion Construction - Present in scattered deposits along creekbeds in sizes commonly up to 2 feet in diameter and in beach deposits of Kachemak Bay in sizes up to 2 feet and through the processing of glacial drift deposits near the dam site. The following assumptions were made for the purpose of estimating costs of the dam: f. Till material is available within one mile of the dam site. g. Pit-run sand can be obtained on the right bank of Fritz Creek. h. Filter material will be trucked from Anchor Point about 16 miles away. i. Random fill can be obtained from excavation in the vicinity. j. Riprap and coarse rock for gabion construction will be available from observed beach deposits at Kachemak Bay. k. Ready mix can be purchased locally. It was also assumed that no campsite will be constructed and the labor force will be located at Homer. These assumptions indicate the loca- tions from which dam construction materials will be obtained. Table 26.1 shows the amounts required of these materials for construction of the three alternative dam sizes. 26-4 6. Reservoir Although the reservoir size is not finalized, it is anticipated that the reservoir will cover approximately 100 acres. Under flood condi- tions, the maximum acreage covered by the reservoir shall be no more than about 200 acres. Table 26.1 DAM CONSTRUCTION - Material Quantities in Cubic Yards Reservoir Size Material 2300 A-F 4000 A-F 5800 A-F Till Fill 200,000 302,000 408,000 Pit Run Sand 179,000 235,000 298,000 (Upstream Sand Shell) Sand Filters 138,000 192,000 246,000 Random Fill 90,000 164,000 225,000 Riprap 60,555 62,625 65,625 Water Transmission Main The water transmission main will consist of two major sections. The first section will run from the dam to the water treatment plant site near the intersection of Fritz Creek with East Road. The second section will run from the treatment plant to a tie-in with the present water system at Kachemak City. The first section (from the dam to the treatment plant) will be approxi- mately 5000 feet in length and will probably follow the west side of Fritz Creek. As this section will run through private property, ease- ments will be required. This pipeline section will run through virgin land; therefore, some loss of trees and brush will occur. The second section of the transmission main will follow the East Road from the treatment plant to a tie-in with the existing water system. 26-5 The exact point of tie-in is not yet identified. The pipeline can be laid within the highway right of way and will require permission from I ~ ~~the the Alaska Department of Transportation and Public Facilities. The pipeline will be buried to a depth of 7 feet with hydrants along the way. No vegetation other than grass will be disturbed by construction, and the length of this section will be approximately 29,600 feet. Treatment Plant I ~~~The water treatment plant process will consist of chlorination, chemical addition, and filtration to remove solids and ensure sanitation. Major I ~~~elements of the process plant will include the chlorination equipment, chemical addition equipment, filters, pumps, air compressors and back- 5 ~~~wash settling ponds. The plant equipment will be housed within a build- ing (approximately 3200 square feet) on the treatment plant site. 1 ~~~26.3 Existing Conditions I ~~~Physical 3 ~~~1. Geology I ~~~The main geomorphic elements of the area are an escarpment of sedimen- tary bedrock immediately north of Homer and beyond this to the north an upland area of the same bedrock almost entirely covered by glacial deposits. 5 ~~~The entire area is underlain at shallow depth by the Kenai Formation which consists of moderately indurated sandstone, siltstone and clay- 5 ~~~stone, mainly in thin beds and lenses, interbedded with a few thin lenses of fine conglomerate and many thin beds of subbituminous or lignitic coal (1). Ferruginous masses and ironstone concretions are common (1). The Kenai Formation is of Tertiary age and is believed to be up to 20,000 feet in thickness (2). -Where observed in the study area S ~~~the beds dip northerly about 4degrees below horizontal. 26-6 1 ~~~Excavated rock of the Kenai Formation, observed in quarries during a reconnaissance of the area, is broken down to sand and gravel sizes. I ~ ~~Confirmation of the softness of the material is given by descriptions of the bedrock at the Bridge Creek dam site where it is described as "generally semiconsolidated into a moderately soft rock . . . cut easily with a knife and sometimes scratched with a fingernail" (2). It is 3 ~~~therefore expected that for dam construction purposes quarries in the bedrock would not represent a source of rock fill but could well serve as a source of sand. The Homer Spit consists of coarse beach gravel and boulders. Apart from 3 ~~~the Spit, the only known sizeable source of alluvial sand and gravel is a pit at Anchor Point, located about 16 miles by paved highway west of I ~~~Homer. 3' ~~2. Topography In the downstream reaches of Fritz Creek,- the creek has cut deeply into the soil mantle, resulting in relatively steep, continuous valley slopes with gradients commonly in the order of 40% to 60% rising from the 3 ~~~floodplain which is limited to widths in the order of 50 feet. Numerous indications of soil instability, such as slumped zones extending 100 1 ~~~feet or so along the base of the slopes and extensive tilting of trees, indicate that at least the upper 10 or 20 feet of the soil is loosely * ~~~consolidated and subject to failure on steep slopes. Proceeding upstream, the valley gradually changes in form with the 3 ~~~floodplain widening and the slopes becoming far more gentle with no significant evidence of slope instability (2). 1 ~~~3. Soils * ~~~As a relatively short time has elapsed since the ice sheet that formerly covered the area receded, the Kenai Formation is mantled by nearly I ~~~continuous deposits of glacial drift. The deposits of this material 26-7 I ~~~observed during the reconnaissance appear to be unsorted mixtures appar- ently deposited directly by glaciers and consisting of clay, silt, sand, I ~ ~~gravel and boulders. These deposits are referred to herein as glacial till. The largest boulders observed in this material are in the order 3 ~~~of 2-foot diameter. While it is reported by others that some of the glacial drift deposits consist of stratified gravelly outwash material, 3 ~~~and a few boulders greater than 2-foot diameter were observed during the reconnaissance, for general planning purposes it i's taken that the over- burden at the dam site discussed herein consists essentially of the unstratified glacial till described. 3 ~~~This material is believed to have extremely low permeability and, while not well consolidated near the surface, appears to be suitable to serve as a dam foundation and as impervious core material for an earth-fill dam. I ~~~As shown in Figure V-2, the soil composition of area covered by the impoundment area created by the dam consists primarily of soils of the I ~~~Mutnala-Salamatof association. The pipeline will run through soils primarily of the Beluga association. Water Rights The water rights granted by the Department of Natural Resources (DNR) in the Fritz Creek Drainage Area include only four small appropriations of I ~ ~~water from Fritz Creek and one small appropriation from a tributary to Fritz Creek. The total amount of water included in these five appropri- 3 ~~~ations is only about 1975 cubic feet per day, less than one-quarter of one percent of the annual mean simulated stream flow. Table 26.2 sum- marizes the Fritz Creek water appropriations. I ~~~~~~~~~~~~~26-8 Table 26.2 FRITZ CREEK WATER APPROPRIATIONS Water Right Appropriation Holder Source Quantity and Use F. W. Wilkens Fritz Creek 500 gpd; domestic use M. Kwochka Fritz Creek 500 gpd; domestic use F. Pavloff Fritz Creek 1600 gpd; domestic use K. B. Star Fritz Creek 500 gpd; domestic use 4500 gpd; commercial use P. A. Carlson Fritz Creek tributary 700 gpd; domestic use 6500 gpd; irrigation Biology The vegetation of Fritz Creek contains three major habitats. These habitats in combination provide shelter and forage for wildlife. The Fritz Creek Drainage Basin provides an abundant resource for upland wildlife. Fritz Creek itself has a natural barrier to anadromous fish. This section reviews the existing conditions of the flora and fauna of the Fritz Creek Drainage Area. 1. Flora The native vegetation in the Fritz Creek Drainage Area occurs as three major habitats: - Sitka Spruce Forest - Native Grasslands - Freshwater Marsh and Muskeg In the lower elevations of the southern Kenai Peninsula, forests are the dominant vegetation (2). Normally forests are found only up to the 1000 to 1500-foot level. Variation in the forested land at different eleva- tions relates to soil and drainage characteristics. The Sitka spruce forests are usually found in the drainage basins of creeks and rivers. They are scattered throughout the area between the lowlands and the 26-9 steep bluffs. The Sitka spruce forest consists of Sitka spruce, white spruce, alder, quaking aspen, paper birch, and black cottonwood. The majority of the forests in the Fritz Creek Drainage Basin have not been commercially lumbered. Trees have been cut from dense forests for elec- trical transmission lines, for roads, and for homesteads. Sitka alder occurs on the slopes and along the large drainage-ways, while willow is common on the slopes and draws (1). Both densely forested areas and isolated clumps of spruce are separated by grassland in the Fritz Creek area. A unique character is provided by the Sitka spruce and open meadows. The forested areas' understory varies from ferns, grass and low-growing berries, depending on soil and light conditions. The forest land is an important feeding habitat for small ground animals, birds, and other wildlife (1, 3). The grasslands habitat of the Fritz Creek Drainage Area consist of native grasses and wild berries. The common species of berries are high and low cranberries, elderberries, raspberries, watermelon berries, crowberries, and blueberries (2). The dominant grass in the native grasslands on the benches and steep slopes of the area is the blue joint reedgrass. Other common plants in this area are fescue, bluegrass, fireweed, and lupine (1). The Fritz Creek Drainage Area also includes freshwater marshes along Fritz Creek, a tidal marsh at the confluence of Kachemak Bay, and muskeg in flat, poorly drained areas. Common freshwater marsh plants include cottonsedge, bog birch, draft willow, lingenberry, and bog blue- berry. The tidal marsh of Fritz Creek is a transition zone between the estuarine environment at the mouth of Fritz Creek and Kachemak Bay and the upland habitats. Most tidal marshes include lyngbye sedge, tufted hairgrass, and beach rye grass (1). 2. Fauna The wildlife and fisheries of the Fritz Creek Drainage Area coincide with the vegetative habitats. The forest land is an important feeding 26-10 N ~~~and rearing ground for the bald eagle. Other birds utilizing the forested areas are owls, hawks, and spruce grouse. The grasslands are I ~ ~~areas that provide habitat for small ground animals, birds, and other wildlife including spruce grouse and ptarmigans. The freshwater marshes 1 ~~~are important for small fur-bearing animals, including wolverines, rabbits, coyotes, wolves, beaver, mink, martin, fox, lynx, and muskrats. if ~~~Moose also utilize the marshes for winter feeding on the sedges, grasses, and other aquatic plants. I ~~~In combination the vegetative habitats provide both protection and feed- ing grounds for Kenai moose, and brown and black bears. The coastal * ~~~area and tidal marsh of Fritz Creek are used by a variety of migratory birds, waterfowl, eagles, and ravens (1, 2). The Alaska Fish and Game Department (ADF&G) has stated that the Fritz Creek Drainage assumes a critical role in moose survival in the area during severe winters. During normal winters, the drainage supports probably less than one dozen moose. During severe winters, however, the 1 ~~~drainage supports higher moose concentrations, 50 to 100 individuals. This is probably due to extreme snow depths in the South Fork Anchor River and the Beaver Flats. The Kenai Peninsula waters are an abundant source of fish for commercial and sport fishing. Halibut, salmon, spotted side stripe, coon stripe shrimp, dungeness crab, king crab, and tanner crab are commercially N ~ ~~fished in Kachemak Say (2). Fritz Creek has been specified by the Alaska Fish and Game Department as important for the migration, spawn- ing, or rearing of anadromous fish. The creek is used to stock coho salmon, and the ADF&G has stated the creek supports pink salmon. The if ~~~creek also contains some land-locked Dolly Vardins (4). 26-11 U ~~~26.4 Impacts and Mitigation I ~~~General In the initial submittal, four alternatives for the Homer Water Supply improvement were considered: - nearby surface sources, - groundwater sources, I ~ ~~~- distant surface sources, and - desalination. Desalination and development of distant surface sources were ruled out 3 ~~~by high costs. Groundwater sources were also found uneconomical largely due to the low yield of individual wells and resulting necessity for a large number of wells to supply sufficient water. In evaluation of the nearby surface sources, Fritz Creek was found to be the only feasible site. In analyzing the unavoidable environmental impacts of the Fritz U ~ ~~Creek site, it is important to consider that environmental impacts of developing this site are comparable to other surface sites and less than development of distant surface water sources. Physical Impacts * ~~~The primary physical impacts will be environmental disruption due to: - excavation of dam materials, - pipeline construction (especially along Fritz Creek), and - building a road to the dam site. Table 26.3 shows materials required for dam construction, quantities required, and availability as outlined in previous sections. Restora- tion of excavation sites will be an important element in mitigating adverse environmental impacts. If material is excavated from state I ~~~lands, excavation will require a Material Extraction Permit from the 26-12 U ~~~~~~~~~~~Table 26.3 DAM CONSTRUCTION MATERIALS Quantity Needed Material (CY) Availability Glacial Till Fill 200,000 - 408,000 Near dam site I ~~~~Clean sand 179,000 - 298,000 Quarries right bank (Pit run sand) of Fritz Creek Sand Filters 138,000 - 246,000 Anchor Point 1 ~ ~~~~(Coarse sand & gravel) I ~~~~Random Fill 90,000 - 225,000 Near dam site Riprap 60,500 - 65,625 Kachemak Bay* *Kachemak Bay is a Critical Habitat Zone and removal I ~ ~~~~of beach deposits may not be permitted. Department of Natural Resources. DNR evaluates each application and * ~~~establishes requirements for excavation operations and site restoration on a site-specific basis. The requirements are formally established 3 ~~~When the Material Extraction Permit is granted. Initial cost estimates for the dam were developed with the assumption that coarse rock for riprap could be obtained from Kachemak Bay. This option may not be I ~ ~~feasible for environmental reasons. Kachemak Bay has been designated a Critical Habitat Area by the Alaska Department of Fish and Game. Initial contact with the Department of Natural Resources indicates granting of a permit to remove beach deposits from Kachemak Bay is * ~~~questionable for this reason. To the extent possible, glacial till and random fill required for dam I ~ ~~construction should be removed from the reservoir area to minimize environmental disruption and restoration expenses. U ~~~~~~~~~~~~26-13 H ~~~Biological Impacts I ~~~Initial responses from the Alaska Department of Fish and Game have indi- cated that preservation of moose habitat in the vicinity of the Fritz 3 ~~~Creek drainage is an important environmental issue. Beaver Creek Flats will not be affected by construction of the dam or reservoir. However, the ability of the Fritz Creek drainage to support relatively large moose concentrations during severe winters may be impacted by the loss of land inundated by the reservoir. Although the exact effects on the moose population are difficult to assess, ADF&G has stated that it is reasonable to conclude the loss would significantly lower the moose I ~~~carrying capacity of the South Fork Anchor River. * ~~~The second important wildlife issue is the maintenance of Fritz Creek as habitat for anadromous fish. The blockage approximately 100 yards upstream from Kachemak Bay limits natural fish runs in the creek. ADG&F, however, will require instream flows to maintain the coho stock- * ~~~ing program (flow rates to be determined). In addition to the above wildlife issues, ADF&G has indicated general * ~~~concerns relating to projects of this nature including: 3 .~~~~~ -deviations of water quality from ambient conditions (i.e., temperature, pH, suspended solids, turbidity, nutrients, etc.), - gravel removal from floodplain areas, I ~ ~~~~- pipeline construction and burial in floodplains, - road construction in floodplains, and I~~~~~ -construction timing. * ~~~Mitigating measures for these potential biological impacts will be specified as terms of the Habitat Protection Permit. I ~~~Construction of the dam may enhance Fritz Creek as a wildlife habitat by mitigating the effects of dry weather'on the creek. In the past, dry I ~~~weather stream flows have been less than 30% of the mean average flow. 26-14 U ~~~The existance of the reservoir could tend to reduce natural fluctuation of stream flow rates, thus maintaining higher minimum stream flows than those occurring naturally during dry weather. 26.5 Permits.-and Regulations U ~~~Federal and State Requirements I ~~~The proposed project will require permits and certificates from the U.S. Army Corps of Engineers and from several State Departments and Commis- I ~ ~~sions. A narrative summ~ary of permit and certificate requirements is given below. Table 26.4 tabulates permits and certificate require- * ~~~~ments. 1. U.S. Army Corps of Engineers The Corps of Engineers (COE) will require a permit for construction of the dam and a permit for excavation of sand and gravel from beach deposits. Application for each permit can be made by submission of completed COE Form ENG'4345, together with a set of project drawings. If there are no objections to the project activity, a permit will usually be issued within 60 to 90 days after submission of the completed application. COE recommends that applicants contact the District Engi- neer Office before submitting the application. Further information is I ~ ~~available in the U.S. Army Corps of Engineers Booklet EP 1145-2-1, "PERMIT PROGRAM, A Guide for Applicants." 2. State of Alaska Governor's Office All projects which require Corps of Engineers' permits must be approved by the Governor's office for consistency with the State Coastal Manage- ment Program. The approval is formally granted by means of the Certifi- * ~~~cate of Consistency with the Alaska Coastal Management Program. 26-15 TABLE V-4 SUMMARY OF PERMITS AND CERTIFICATES Federal or State Agency Permit or Certificate Application Procedure Time Required U.S. Army Corps of Department of the Army Submit COE Application 60 to 90 days if there Engineers Permit Form ENG 4345. are no objections. Alaska Governor's Certificate of Submit application form Processed with COE Office Consistency with the with the COE Permit. permit. Alaska Coastal Management Program. Department of Natural Permit to modify or Application currently Resources Construct a Dam on file with DNR. Water Rights Permit Application currently on file with DNR. Gravel Extraction Submit DNR Material 3 to 4 months, possibly Permit Application Form. longer. Department of Certificate of No specific procedure, Processed with COE Environmental Reasonable Assurance evaluation completed as permit. Conservation part of COE permit process. TABLE 26.4 (continued) Federal or State Agency Permit or Certificate Application Procedure Time Required Department of Construction and Applicant must inform Construction permit Environmental Operation Certificate DEC of project and granted within 30 days. Conservation submit design plans for Interim authorization preconstruction to operate granted up approval. project completion. Final operation certification granted UN) ~~~~~~~~~~~~~~~~~~~~~~within 90 days. I-4 Public Utilities Certificate of Public Submit Certificate 3 months. Commission Convenience & Necessity Application Form to PUC. Department of Fish and Habitat Protection Submit full plans and 30 days if sufficient G ame Permit specifications to data for evaluation is Habitat Division of available. ADF&G. I ~~~The Certificate of Consistency application form is a simple one page form issued to the applicant along with the COE permit application form. I ~ ~~The application for the Certificate should be submitted with the COE application and will be evaluated as part of the COE application. The 3 ~~~Governor's office must grant the Certificate of Consistency as a pre- requisite for a COE permit. U ~~~3. Department of Natural Resources I ~~~The Department of Natural-Resources requires three permits: a. Permit to Modify or Construct a Dam b. Water Rights Permit * ~~~~c. Gravel Extraction Permit Applications for the Permit to Construct or Modify a Dam and the Water I ~ ~~Rights Permit are already on file with the Department of Natural Resources. The Gravel Extraction Permit is issued after a Material I ~~~Application is submitted to the Department of Natural Resources. Processing of the application requires at least 3 to 4 months and can 3 ~~~take longer depending upon the material quantity requested and condi- tions at the site. A charge is levied by DNR based on the fair market value of the material removed. * ~~~4. Department of Environmental Conservation The Department ofEnvironmental Conservation (DEC) requires two certifi- * ~~~cates: * ~~~~a. Certificate of Reasonable Assurance b. Construction and Operation Certificate I ~~~The Certificate of Reasonable Assurance'refers to water quality effects of the proposed project and is issued' as part of the COE permit process. I ~~~No separate application is required to obtain this Certificate. The COE 26-18 I ~~~permit application will be reviewed by the Department of Environmental Conservation and the Certificate issued if no significant adverse water quality effects will result from the proposed project. 3 ~~~The Construction and Operation Certificate is issued by the Department following a Plan Review for Sewage System or Water and Wastewater Treat- ment Works. There is no formal application for this Certificate; rather, the applicant should inform DEC of the proposed project via correspondence. After the project design is completed, the applicant must submit the plans to DEC for the Plan Review. Plans for all ele- ments, the dam, treatment plant, and transmission line will be reviewed 3 ~~~and ruled upon within 30 days. If the plans are acceptable, DEC will issue the construction portion of the Certificate authorizing construc- 3 ~~~tion of the project. After construction, DEC will authorize plant operation for a 90-day interim period during which DEC will verify the project was built according to the authorized plans. After verification I ~ ~~of the construction, DEC will issue the operation portion of the Certificate. 5. Public Utilities Commission The Public Utilities Commission (PUC) of the Alaska Department of Commerce requires a Certificate of Public Convenience and Necessity for operation of an installation that provides water or sells electricity to the public. The certificate is granted on the basis of service area, I ~ ~~and new facilities which serve previously certified service areas do not require a new certificate. If a new certificate is required, an appli- 3 ~~~cation packet is available from PUC. The application information includes financial statements of the applicant, managerial experience of 3 ~~~the applicant, and the proposed service area. The time frame to obtain the Certificate is approximately 3 months. 26-19 6. Department of Fish and Game The Department of Fish and Game requires permits under two state laws. The laws protect habitats of anadromous fish and require a permit for any blockage of streams with fish runs, and also require a permit for construction in any state waterway containing fish. The permit process usually lumps all requirements for the project into one permit known as the Habitat Protection Permit. The Department of Fish and Game also has jurisdiction over maintenance of instream flows which is reflected in the terms of the permits. The time frame for issuance of permits is 30 days after submission of the application provided sufficient data for evaluation is included. REFERENCES 1. Water Resources and Surficial Geology of the Homer Area, South-Central Alaska, Roger W. Waller, Alvin J. Feulner, and Donald A. Morris, Hydrologic Investigations Atlas HA-187, Dept. of the Interior, U.SG.S., 1968. 2. Foundation Investigation for City of Homer Dam on Bridge Creek, Hill-Harned & Associates, April 1974. 3. Homer-Ninilchik Area, Alaska, Soil Survey, U.S. Debt. Agriculture, July 1971. 4. Homer Comprehensive Plan - Olympic. 5. Homer Comprehensive Plan Revision, 1978, CH2MHill. 6. Soil Conservation Service, 1971 (referred to in the Comprehensive Plan - Olympic). 7. Water Reservoir Study, CH2MHill, October 1980. 26-20 I U II II SECTION IV PUBLIC PARTICIPATION I I I I I FISH AND GAME MEETING SEC. 27.1 MAY 5, 1983 City Engineer Jan Keiser opened the meeting and called for introductions around the table: Present: Jan Keiser, City of Homer, Engineer Phil Brna, ADF&G Habitat Division Joe Wallis, ADF&G Sport Fish Division Brent Leslie, Crippen Consultants Dave Swenson, Olympic Associates John Nagy, Olympic Associates, Anchorage Nick Dudiak, ADF&G, FRED Div. Homer Tom Schroeder, ADF&G, Commercial Fisheries, Homer Dave Holderman, ADF&G, Game Division, Homer The City Engineer Keiser thanked the representatives present for their quick response and their presence in Homer. She explained that the City has been studying the poss- ible development of a new water source. Olympic and Associates and Crippen have been contacted for preliminary studies. Material has been gathered and the City feels that input from Fish and Game is now necessary. Ms. Keiser reviewed work to date stating that the City and Olympic have been working together since September, 1982. It was determined, that the city does need a new water supply. Indications show that on a dry year, with water demand projections now evident, Homer could have a problem with the present supply of water. Other sources have been studied: ground water, 3 different surface water sources, desalin- azation etc. Engineer Keiser reported that,.according to the studies so far, it appears that a surface water source will be the most practical. Three potential sites have been identified: Bridge Creek (the existing source), Twitter Creek (north of Bridge Creek), and Fritz Creek. Each was studied as to how much water~ould be produced, what the economics would be in capturing that water and the possibility of that water satisfying the projected demands. _Fritz Creek seems to be the best source to provide the projected demand... Fritz Creek also provides atbetter quality water. Ms. Keiser stated that three potential sites for a structure on Fritz Creek had been identified and now the environmental questions, the in-stream requirements etc. had to be answered. ADF&G representatives stated that they have two basic'areas of concern: moose and fish. Mr. Holderman stated that he was concerened about the proposed dam sites as it would conflict with moose resources in that area. Fritz Creek drainage is a broad river bottom and it's part of a larger wintering area north and west (Beaver flats and south fork of the Anchor River). Mr. Holderman stated that the area is heavily used by moose during winters of heavy snow concentration. City Engineer Keiser presented a map of the proposed three sites. Site #1 will occupy 22 surface acres. Site #2 will occupy 46 and site #3, the preferred site for geotechnical and hydraulic reasons, will require 157.acres for-a 100 foot damn. Brent Leslie explained that the lower in the creek the site is located, the higher the damn would necessarily be. Mr. Holderman stated that due west of the Fritz Creek site, is the Beaver Creek watershed which is extremely important as a wintering area for moose. In a normal mild winter, Mr. Holderman estimated that there would be a dozen to two dozen moose in the flood area. By developing the preferred dam site, he feared that the carrying - capacity of the entire south fork drainage would be lowered. FISH & GAME MEETING MINUTES MAY 5, 1983 - 2 Mr. Holderman stated that the other species which will be adversely affected by a dam site would be the beaver, the population of which the City would obviously want to keep at a minimum in the dam area. Mr. Holderman stated that the annual harvest for the sub-unit (everything south of Tustumena) would average 200 bulls/season. He could provide statistics for the harvest in the specific drainage. The resource is used primarily by those living on the south end of the Kenai Peninsula. Mr. Holderman stated that his desire from the City would be that they consider Twitter Creek. If the Fritz Creek site does come to be, he suggested a land swap wherein land could be obtained that would be beneficial to the moose resource. Mr. Vernon stated that Fish & Game would ask for an alternate dam configuration which would minimize habitat disturbance such as going with one of the lower stream alter- natives, or lower the level of the dar or something to minimize the impact. It was explained that the peak demand for water occurred when the cannery required processing water. Service would be provided to everyone along the pipeline from Fritz Creek into the city limits. Discussion was held about the possibilities of damming below the confluence of Twitter and Bridge Creek. It was explained that some silver salmon and some dolly varden use Twitter creek. Bridge Creek is not presently used to full capacity. It was explained by ADF&G representatives that when the Bridge Creek structure was built it was done so with the understanding that all of the creek would not be dammed so that fish habitat would not be impacted; to go back and reverse that decision would not be wise at this point. Engineer Keiser asked the Fish and Game representatives as a whole to advise the City what steps would have to be taken regarding the site on Fritz Creek or make a definite statement that the site is not suitable. Fish and Game asked for as much information as far as size, price,exact location etc. for each of the sites as ossible. Engineer Keiser stated that the estimated construction costs for #3 were 4 million; for #2, 16 million; and for #3, 23 million because of the construction difficulties. Fish & Game representatives stated that moose would be the number one priQrty, the number one species impacted and fish would be second. Discussion was held about the future use of theluplands area of Beluga Lake. The land is held by Department of Transportation and zoned commercial II and residential. Mr. Holderman stated that it is an area that Fish & Game would be interested in. Ms. Keiser reported that when DOT was in Homer recently for a public meeting on the Airport Master Plan they stated that the Department had no plans to protect the area. She suggested that Fish & Game contact DOT soon since they are in the process of putting together information for their master plan. Fish and Game representatives explained that Homer is growing so quickly that moose habitat is suffering and as more subdivisions are put in, land like Fritz Creek becomes mre important if we are going to keep moose in the Homer.area. Mr. Holderman explained that at one time the Homer Bench area was the most important moose winterinc range on the entire peninsula. At present it's being developed so I ~FISH & GAME MEETING MINUTES MAY 5, 1.983 - 3 quickly that it's being lost. Fox River Valley, the number 2 wintering area, is I ~also being encroached upon. Engineer Keiser explained that some municipalities have ordinances that provide U ~for watershed protection. By building the Fritz Creek dam, the habitat would be protected whereas now, that land is in the hands of others and there are no provisions for protection. The representatives from Olympic Associates and Crippen explained that it is a mixture of ownership at this point. There is University, Borough, and private property involved in the area. Fish and Game asked Olympic Associates and the Cityt produce some calculations I ~on areas of inundation at the three-sites based on optimum dam configurations and also on various flow releases. This will allow them to weigh fish and moose * ~against economics and- come up with an alternative. Mr.'Swenson explained to Fish & Game that it would be presumptuous for Olympic I~~to come up with the fl'ows required for the fisheries and asked that Fish & Game provide that information for the City. Mr. Wallis from Fish &,Game expressed the feeling that the major impact at any of the three sites would be on the moose population. Anything that was done I ~would improve the habitat for fisheries. At present there is a small population of Dolly Varden in the stream. It is not an important or significant fishery. rn ~There Is a -program o~f planting _silver salmon smolts at the highway culvert. Mr. ijudiak stated that the smolts are released between mid-May and mid-June. At times they will remain in the stream for a month before they head out to sea. Their only concern is that there be an in-stream flow during that time. Adults return between August and October and stream flow should be maintained during that time also. If there is a possibility of stocking coho salmon in some other area to get the same fish into that area, then the in-stream flow can be reduced 3 ~or eliminated during that time. Homing would not be to Fritz Creek. There is no need for spawning or rearing flow. The 60% mentioned in the waiter source study is not a firm figure. Additional study would be needed to determine the needed flow. When the stream flow has been monitored during release, it has been about 10 CFS in the month of June. It was, the feeling that about half that would be sufficient for the smolt. El~~f there was some way to re-channel the outlet of Beluga Slough so that it would flow into Miller's Landing, that would provide a return for adult cohos and smolt could be stocked in Beluga Lake-and the adults would come back there. A small channel could-be dredged through the existing swamp without endangering the moose habitat. Mr. Brna stated that an in-stream flow analysis is a very simple thing and will have to be done before a final opinion could be arrived at. The main concern is to provide transportation water for the fish from the road to the outlet of Fritz Creek. It was explained that it is not really a concern that returning adults enter the streams once they reach Mud Bay area.. Mr. Schroeder explained that one experiment that ADF&G is interested in pursuing is to dump fry into a reservoir. A rainbow trout fishery is also badly needed I ~and could be experimented with in conjunction'with the water project. Dangers in allowing a fishery around a water source were discussed. I ~~FISH & GAME MEETING MINUTES MAY 5, 1983 - 4 I ~It was discussed that the total flow in Fritz Creek could not be cut off. Residents .would complain. Ther# are existing water rights. People are presently using Fritz Creek as-a water supply. Engineer Keiser pointed U ~out that were the Fritz Creek.-dam implemented, these people using Fritz Creek water would be supplied by the City eliminating the needs for water I ~~rights. In summary it was stated that different dam configurations need to be looked at to minimize adverse environmental impacts and maximize economic return. The two environmental concerns, moose and fish, may be contrary to each other so the different configurations need to be looked at based on different in-stream flow requirments and relate that back to the moose habitat that I ~would be lost. ADF&G would also like to study the possibilities of stocking fish in the reservoir created. Engineer Keiser stated that the City and Olympic Associates will conduct an I ~in-stream survey to project the in-stream flow requirement. This will be used for the basis for development the alternate dam configurations. Fish and Game reported that there is no smolt release scheduled for 1983. I ~There are no fish available. Olympic Associates and the City agreed that the in-stream flow study would be conducted during the last two weeks of May or the early weeks of June when fish normally would be released. Further discussion on in-stream flow requirements could be held toward the end of I ' Engineer-Keiser estimated that the project will be considered sometime between five and ten. years in the future. There are political and social issues which will take many years to answer. 3~~ADF&G representatives asked that a land ownership map be provided. City-Engineer-K-eiser thanked the Fish and Game representatives for their I ~attendance a~t the meeting. 3 ~~~~~~~~~~~~SEC.' 27.2 3 ~~~~~~HOMER WATER SOURCE IMPROVEMENT STUDY PUBLIC WORKSHOP I ~~~~~~Tuesday, September 131983 7:30 PM 3 ~~~~~~Homer High School Team Teaching Room The City of Homer has been studying ways of obtaining more water to I ~ ~~supply a growing population. The workshop will offer an opportunity for you to speak with members of the consultant team studying the project. Questions raised and information collected at the workshop will be incorporated into a draft report to be published this fall. Topics to be covered at the workshop-will include: o Capacity of Homer's existing water supply. I ~ ~~~o Plans for expansion of Homer's water distribution system and need for additional water supplies. a Costs and-feasibility of possible sources of additional water. I o~~~~ Environmental and water rate impacts of developing a dam on .Fritz Creek as a new water source. o Long range timetable for study, design, permit application and construction. All interested residents are encouraged to attend. For further 3 ~~~information, please call 235-43(.11 Costs for developing the system vary depending on the size of the reser- voir desired. The smallest dam size studied would have five times the storage capacity of Bridge Creek reservoir, and would cost a total of $19 million, while the largest would have ten times the storage of Bridge Creek's reservoir and would cost $28 million. The City of Homer probably could not afford to build the project on its own, since there would not be enough customers at least initially to support a project of this size. A combination of State grants, expanding the service area to include Kachemak City and other east end areas, and perhaps building the project in stages would be needed to make the project feasible. The purpose of this workshop is to inform interested persons of the work which has been completed to date, and to allow an opportunity to consider suggestions and new information. If you are interested in receiving a summary of the report when it is prepared, please clip out the coupon below. NAME ADDRESS TELEPHONE WORKSHOP SUMMARY HOMER WATER IMPROVEMENTS STUDY 5 ~~~~~~~~~September 13, 1983 3 ~~INTRODUCTION Homer has grown rapidly over the past two decades, and at its current rate of growth, its population is doubling every seven to eight years. I ~ ~This population growth has put a strain on existing public water supply sources. I ~ ~Homer's existing water source, Bridge Creek, was first developed in 1974, but is likely to be insufficient to meet demands within the next several years. Conservation programs could help avoid a shortage, but if population continues to grow and additional fish processing plants I ~ ~are established as planned, a new water source will still be needed before the end of the decade. In fact, in a dry year, water shortages could occur as early as 1985. I ~~Recognizing the need to begin developing water supply solutions now, the City of Homer retained Olympic Associates Company and Crippen Consultants, Inc. to evaluate water supply alternatives, prepare preliminary design and cost estimates of the preferred alternative, evaluate environmental and rate impacts, and prepare a detailed plan of 1 ~~action for developing the new water source. WATER SUPPLY ALTERNATIVES I ~~All practical alternatives were investigated. Initial study showed that there were a total of six possible sources. They included: 1 ~~~(1) Raising the existing dam on Bridge Creek to increase storage capacity; (2) Construct a dam and reservoir on Twitter Creek; (3) Construct a dam and reservoir an Fritz Creek; I ~~~(4) Develop new wells to tap groundwater supplies; (5) Construct a submarine transmission line to carry water I ~ ~~~from China Poot Lake to the end of Homer Spit; and (6) Construct and operate a reverse osmosis desalinization * ~~~~plant on Homer Spit. All six were given equal consideration in the first phase of the study. The list was narrowed down based on cost, physical potential and other factors as the study progressed. 5 ~~Bridge Creek was ruled out since the existing dam is constructed in a manner which would not allow it to be safely raised, as well as the fact that the limited additional quantity available would not justify the I ~~cost of essentially constructing a new dam. China Poot Lake was found to be prohibitively expensive due to the high cost of constructing a submarine water transmission line across Kachemak I B~~ay. In addition, since the lake is within Kachemak Bay State Park, the project might be considered to have excessive environmental impacts. The technology of desalinization of seawater by reverse osmosis is I ~ ~developing rapidly, but operating costs are very high. Major factors are the high cost of energy to pump the seawater under high pressure past the reverse osmosis membranes, as well as the need to heat the I ~ ~water to a temperature which is suitable for efficient operation of the plant. Groundwater was utilized by the City prior to develophient of Bridge Creek. Currently, wells serve as the major source of water for most Homer area homes not on public water supplies. Predicted yields of 3 ~~individual wells are low, and many wells would need to be drilled to satisfy water demands. The cost of drilling, power, treatment and pipe- lines would not be cost effective. Twitter Creek was found to have a slightly higher flow than Bridge Creek, but due to watershed terrain, dam construction costs would be high. Cost per gallon of water produced would be higher than for Fritz Creek. In addition, a Twitter Creek dam would only satisfy another 10 to 15 years growth in water demand before another new source would be Fritz Creek drains a large watershed, producing more water than Bridge and Twitter Creeks combined. Topography of the watershed is such that the dam could be constructed safely and without complications and water treatment needs would be less than for Twitter Creek. Cost per gallon I ~ ~produced would be less than for other alternatives and the transmission line could be tapped to supply Kachemak City and other east end areas if 3 ~~des ired. FRITZ CREEK PROJECT CHARACTERISTICS I ~~From economic, environmental and safety standpoints, Fritz Creek would be best developed by constructing a dam and storage reservoir. Three possible sites were studied on Fritz Creek, and cost estimates and preliminary designs were prepared for all three. Preliminary designs and cost estimates were also prepared for a water treatment plant and a ~~transmission line to Homer's existing system. a. ~KBBI PROGRAM re: FRITL. CREEK WATER SUPPLY STUDIES -SEC.: 27.3 LF: As most of you are probably aware, the engineers have been doing some study regarding the water supply for the HOmer area for some time. Tonight they're U ~ ~~here for what they call a workshop, to present the workshop summary to deal with questions and answers and your concerns in relation to the ..to bring you up to date where they are. So that everybody will know I ~ ~~w'ho these people are I would like to introduce first Jan Keiser who is the City Engineer and who will, in turn, present to you the consultants who are going to be doing the presentation. I ~~~Does everybody have one of these handouts? I ~~~OK. JK: We've got four people with us who represent the engineering company that worked on the study which has been in progress for almost a year now or I ~ ~~so and~we're to the point where we've got a draft report and what we'd like to do is summarize that report for you tonight and answer questions in case any comments that you folks might have and put that into a ...compile that into our report and then go ahead and publish a final one. Let me just introduce the folks that are here tonight ... we 've got Dave Swenson with Olympic & Assoc. who was the project engineer from Olympic. Howard Hillinger with Pacific Rim who can speak about environmental and land - use type questions if anyone has any particular questions on that. I ~ ~~We've got Rolf Scrindy with Olympic and Assoc. who can speak on a wide variety of topics an just about anything but specifically the gecitechinical portions of the dam and Brent Leslie from Crippen & Assoc. who is a water 3 ~~~expert. David is going to give you a brief summary of the report and then we'll just open it up to questions. I told them not to talk a minute longer I ~ ~~than 30 minutes so just bear with us while we go through that and then you can have at it. And Eileen is going to be taping this so try and speak clearly and loudly from the back there if you do have a comment, so we can get it on record. IApproximately 30 minutes of discussion by the various consultants. I~~~~~~~~~~~~~~~~~~~ OLYMPIC ASSOCIATES CO. * -1.- ~~~~~~~~~~~~~SEATTLE I ~Questions from audience: MR. GRAY: I ~~~I'd like to have someone address ... this is kind of a lengthy thing. First of all, if, let us say, Fritz Creek is selected, there are three different volumes of water storage that are being proposed, is that correct or are you talking just on the top one there? I JK: There are'three specific sites that have been looked at, that first site... GRAY: At Fritz Creek? J K: At Fritz Creek. Our preferred site is the upper most one here. GRAY: OK, given that as a selection, what is the size, the area size of this, how many acre feet are you going to be able to store and how much rate of water I ~ ~use, inthat you have two different varying amounts of run off that you have to guarantee, how much is left in that facility for use by the City? I think in volumes of water that large, acre/feet is perhaps the smallest I ~ ~volume designator that we can use. JK: Let me see if I've got your question right. You want to know what volume of water would be left to the City if we built a dam that we're proposing and still leave the flow that we're required to leave in that stream? IGRAY: That's right. JK: That's a good question. We don't ... we have a range of answers but because the size of the dam and the volume of water behind it is based on primarily .. what Fish & Game requires us to release out of... IGRAY: That's what I say. Take the two figures, 60% and 28%... JK: Well, there's even a wide range beyond that. 60% is very very conservative figure. That was a figure that they gave us when they didn't even really know what we were doing. They just kind of give you 60% as a stock answer when you call up and ask them that question. IGRAY: Let's use 60-.what are you looking at? JK: Well, with-.so when we took a closer look at it, we thought that maybeI the range could vary as much as ... vary as low as 28% and then we had a discussion with F&G and their prime interest really wasn't so much with the fish, so much as it was with the moose habitat and we thought well maybe we could get by with as little as 15% and so we need' to go through and do these. Brent can go through and give you the specific figures on the acreage behind the various ranges but it just varies so much, Robert, that it's really hard to give you a specific figure. GRAY: Well, I'd like to know, when the dam is full up is what we're talking about, how much water is going to be behind the dam and what volume are we talking about in the ... in the range of acre/feet unless you want to use a bigger figure, I mean a bigger... gig A. Well, let's go for, the gusto here. I'll give you the biggest number you'regon 3 ~~to get out of me all night, how's that? If we're required to use 600%0 in-stream flow, if we decided to meet the City's demand for year 2030, if the city demand is that high, that's based on the assumption that you're going to receive atleast 2 additional canneries between now and then and maybe your population will continue to grow, and also assuming we can build the dam that high without the environmental problems of the moose people, saying "no, you're not going to flood the moose out", then we're talking about a volume of 5800 acre/feet. I ~GRAY: OK, ah ... I figured 1033 would meet the ... well, that's splendid. A. You see ... that's the absolute, way off the end of the scale spectrum that is almost an impossibility to happen. It's not a realistic number. But that is..the worse case that we've looked at in our study. I ~GRAY: And in addition to this, is this in a seismic sensitive area? A. Well, the entire region is in zone 3. In other words, if you're familiar with seismic zones.' If you're not, that means you're in a...not the worst I ~ ~zone, but you're in the second worst zone. However, all of Alaska, pretty much, is in that zone, along with southern California ... IGRAY- Well, it was just a matter of curiousity. This figure that you gave me, this great big figure, I think I can live with thatone. Thank you. EQ. Can you tell me why Beaver Creek wasn't explored for water? You don't even have it mentioned here... it has a far greater watershed than Fritz Creek does? I UJK Why wasn't Beaver Creek explored? Brent? I don't think it was ever even really mentioned as a... Everybody knows Homer needs water. JK: I've only been in Homer for about a year, so I'm not really sure I even know I ~ ~where Beaver Creek is. EQ. ~~Beaver Creek watershed is enormous. 0 JK: Oh, well, that's even farther away than... EQ. ~Well, you have the water here and-it flows into Anchor River, this is Beaver Creek right here. IJK: Oh, OK, I see. Oh, it's a fork of the Anchor River? Q. Yes, that's right. I JK: Oh, OK. That was the problem. With several of the forks off the Anchor River is Anchor River is a very sensitive fish area. The F&G were entirely upset when we even discussed using any fork of the Anchor River that would reduce its flow. Fritz Creek is not so sensitive because it's not actually a spawning area. But Anchor River, they were adamant about taking anything out of the Anchor River watershed that would reduce its flow. Q. Well, I think you should put the pressure on them to build the dam up there instead of coming down here in to a residential area and jeopardizing the people here. This gentleman talks about the earthquake...are you a geologist? A. I'm trained to geotechnical engineering, yes. Q. Are you a geologist? A. No, I'm not a geologist. Q. Then you're not academically qualified to talk about. A. I am academically qualified to talk about it. But I am not a geologist. 3 Q. Another question I want to know is...have soil tests been made on this property? JK: No. Soil tests, as I said before, have not been made on Fritz Creek. S Q. Then you don't know what the saturation point of the mud flats out there, whether it would hold that or not? JK: Not for the Fritz Creek site specifically. We did have some geologists come down and look over the area and they were able to look at the area, compare it to some of theother soil tests that were made in the Homer area and make some comparisions and they didn't feel that there would be a problem but we haven't done soil tests specifically. Q. Did they do this from the ground or from the air? JK: They did it from the air and from the ground. They did make... Q. They got in some helicopters and just flew around. JK: That's true...they did fly around in the helicopter cause I was in that helicopter but they also made, it was walked over the ground. Q. They made one landing. JK: Well, they made several trips or maybe you didn't catch everytime that they were up there but I do know that they did walk the area because they did tell me that at one point they were told not to cross private property so they had to have been on the ground. Any other questions? Yes, sir? Q. Yes, two. One is to the cost exposition on the present existing facility at Bridge Creek...mainly why in the existing facilities there that you know pump station and reservoir-and chlorination tank...why couldn't that be expanded, and a larger area .... (inaudible).-.you have existing facilities in and out, there's no problem as far as access to it, that was one of my questions. Just on cost exposition in that situation. Another one would be ecologically speaking, what happens if you innundate that whole situation at Fritz Creek and recently there's been 50 acres of Timothy plant there, plus there's a lot of other vegetation, to the best of my knowledge, when you innundate an area like that, you have a rotting situation going on with the present and the existing vegetation that's under water and this creates a toxic situation along the whole outlet for a couple years and so that...has that been considered? JK: Well, let me answer your first question first. Let me see if I've got your first question straight.- You were-.your question is, was the expansion or building of an expansion of Bridge Creek looked at and #2 was building another dam below Bridge Creek looked at, is that your question? Q. Yes. g 3~K: OK, expansion of Bridge Creek dam itself was looked at and it was determined not to be feasible because of the way they built bridge Creek in the first place. Q. How about exploring below it? I mean, couldn't you have a series of steps or terraces? 3 3~K: If we have one lower then we'll have a head problem on being able to get water back in to the treatment plant, we'd have to pump it up and get it back in the treatment plant and then the... 5 ~Q. You could use another pumping station. JK: Yes, but then the other problem is of the stream flowed that we're required to release in Bridge Creek. Q. This was determined by the magic people at Fish & Game? 1 3KR: To a certain extent, yes, that's true. Now, to your question about the decaying vegetation and the dam itself, it,'s something you just deal with Q. But I don't know what :you would control the spill over to the point where there would be no toxicity below the dam. In other words, with water I ~~rights, how do we get protected? 3K: How do you get protected from the toxicity? A. This' is a subject that people learn more about as they develop water I ~ ~reservoirs. The vegetation in the water reservoir causes tannens to be released and discolored and so on-.because of that, although they can be-treated, removed in a treatment plant, it's been increasingly common to remove as much vegetation as possible from that reservoir before it becomes filled up with water, although a lot of places don't do that, j ~~it certainly gives you the problems of color especially downstream. There's no toxicities even (inaudibl~e)provides poorer water quality, it's a little bit acidic... Q. I would dispute that. You have to take into consideration the tons and tons of fertilizer that's been dumped on that land back there ... 3 K: On the University's land? No, this is something that would have to be looked at too. Yes, sir, in the back. I Q. Ifhaveha question about the first chart. You said you studied the flow of achindividual creek and the amount of flow in a dry year. When did a ~~you do that on Fritz Creek? J K: I'm sorry, when was it done? (). HIow mainy gallons a day did the flow pass...I presume that that's what that chart was? When did yoU.do that on Fritz Creek? JK: Ah...well, it wasn't done at a specific time. Brent, do you want to discuss the hydrology, just a little? BRENT: The hydrology, as you know, is a very adaptable science to the computer. And what was done is because of the lack of a gauging station on Fritz Creek and you need a gauging station if you're (inaudible) of atleast 20 years to establish anything to work with, we had to go to the Anchor River, where the nearest gauging station for that period of record, and then, by interpolating the percipitation records in the Homer area the range area, what we did was we actually simulated on the computer the flows. Then we Gross checked those by the records that were available on other streams that we simulated here in the area - there are 2 other streams in the area which have records which are less than 20 years close to Fritz Creek and we checked our computer simulation model against the short- term record and we found that it was extremely accurate within 1% so we were satisfied that we've modeled the stream to a degree of accuracy sufficient to predict the supply of water that's available. Does that answer your question? Yeah, it does but the reason I asked that question was because just two or three years ago that thing was dry as a bone in the winter. We take our water out of it. (simultaneous'speech - inaudible) revert back to your in-stream flow of 60% instream flow or whatever, if you put that at 60% or 28%, people who have water rights, who are taking their water out of there now, are just not going to have any water at all. JK: Well, one thing that we would like to do as part of this detail work is put a gauging station on Fritz and collect more data on the creek itself, rather than rely entirely on the model.We'd be able to go back and correlate the model a little bit better. That-would take 20 years? JK: Well, I don't know if it would take 20 years but... 3 Q. The engineer just said 20 years to get a correct deal. JK: 20 years if you're starting from scratch with no data. We do have a model that we would be able to use as a comparison. All we...we have a model, what you need is then some records that you can go back. in and verify whether or not your model is telling you the truth or not. And it wouldn't necessarily take 20 years for that. Q. Well, basically then, this 600, 000 gallons you've given us is just something you've plucked out of the air? JK: If you want to put it like that. something the computer plucked out of the air. I A. I would like to answer another question that didn't get answered before and that was the question on the water rights...people who are already taking water out of the creek. As some of you probably know, the state has a block model or a water code and that code provides that people have prior right depending on when they acquired the water rights, but it also provides that -6- public water supplies have priority provided that if the people who have prior rights are destructed that they be compensated. That compensation I ~ ~might be monetary or it could be water. It could be that in some cases the municipalities-.when they built water ... water supply systems and deprived people from being able to pull the water out of the creek, I ~ ~~part of those agreements might be to sell water to those people at a certain price but state law does require that people that the prior rights, either be protected or they be compensated. So that would be I ~ ~a matter of-.discussion. Usually those people get water from the municipality. I ~Q. What percentage of that water would go to the two canneries that this other gentleman mentioned and what percentage would go to the general population for commercial ... or residential use. I~~A. Well, I'don't have the exact figures. It was actually the projection was for one additional cannery. I think you can see it there over on the chart on the wall, it's not easy to see from here but you're talking about, oh at the present time,'yott've probably' got, oh, about a quarter athird of the demand, is by the processors. As the population grows, that's going to be a smaller and smaller percentage of the demand. I ~~. I have a report here from the U.S. Government and it says, fault'is 3 km. NE of the mouth of Fritz Creek, where is that at on that... 5 ~JK: That would be ... well, there's a fault that runs approximately like this up through here, not just in one spot, it's ... you know, it runs along the length of the ... a certain portion of the length of the 5 ~~creek and then goes off into the hill. Q. Can you tell me now why you would even consider putting a dam that 3 ~~close a proximity to a fault? A. Well, the fault is considered an inactive fault by seismologists. I ~Q. In '64 it was sure not inactive. Q. The seismologists figured that big quake we had in Anchorage was inactive I ~~and they're all inactive until they move. JK: Well, you know, that's-certainly true. I ~Q. So, why even consider putting a dam there and jeopardizing people in the area? I ~A. There is a fault that runs across here, it comes all the way from Kamchatka Bay. Now in that-.you're correct, there. was an earth quake here years ago you're incorrect, it was not caused by- that fault. If it was caused by that I ~ ~fault, you would have been able to go up there and see where the earth had moved. You'd be able to see a line all the way across the countryside where that moved. It was caused by a... I Q. ~Want to take a walk someday? 3 ~A. Pardon me? -7- 3 Q. ~Want to take a walk someday? A. OK, well, we surveyed it aerially and we also have USGS reports. FAults are highly visible from the air, they're very obvious if you know what I ~~you're looking for in an aerial photograph. It's very simple to see t~hem. The fault that caused the earthquakes around here is not located here it's located on the other side of those mountains. YOu will have earthquakes here. There's no doubt about it. But that's not the point. The point I ~ ~is, will the fault shift this way. Not whether you will get shaking...there's no doubt in our minds that the ground's going to get shaken here. It has in the past, you've all felt it, it will in the future, you're going to get some good shakes. That's not a problem from a design point of view. The only thing that even comes close to a problem would be a major shif't, vertically, in the sails crust right underneath the dam. In other worts, we would have to build the structure across this fault and it would have to shift, on a soils structure like this, a minimum of three feet before there would be any consideration of-a problem. If.. and even then it's not likely to have a problem because this dam is just like the dirt out tere, that's all -it is., It's not that big of a problem. Now, back to the question of active fault and inactive fault. An inactive I ~ ~fault is a fault line where there's a dip or a strike in the earth's crust. All that means is sometime during the formation of the earth beyond a million years ago, OK? To be classified as an active fault it has to move in the I ~~last million years. That fault hasn't moved in the last million years, according to the USGS report and according to their maps. And if anybody wants to discuss that further we can get into it in mass and get very heavy 3. ~~and complicated. Q. But we're still a zone 3. IA. Right, but what I'm saying is Alaska is zone 3. Zone 3 doesn't make any difference, OK? You can shake it all you want, as long as you don't displace a significant erruption, you can shake it all day long, it ain't gonna hurt it, it don't care. What I'm saying is the earth can shake, move, accelerate in any direction it wants to and it's not going to bother the structure that can be overcome very simply, in thedesign plans. The only thing is an act.-that could be a problem, is that you build it right on an active fault and it shifted a large amount. I ~~* Where is the closest active fault? A. OK, well...I'll tell you what we ought to do ... rather than waste this whole meeting on a fault geotechnical discussion which a lot of people don't care 3 ~ ~about ... the people that care about that, let's get together, right after we have this question and answer session and we'll get out the maps and ... EQ. We all care about it...this room needs to be educated. A. OK, do you have a map. Zone 3 doesn't have anything to do with this, all 5 ~~we're talking about is an active fault.' Q. Oh, yes it does. I Q. ~The question to me is why are you going to put that there when you get that from China Poot... 3 ~~(simultaneous speech -inaudible) -8-. JK: Sir? Q. I would like to know how you.'re going to finance this project? JK: That's a problem, a real problem. We don't have the answers to that. We looked at various ways of raising the money, the obvious ones, of course are grants from the state or the feds, we did look to see if the water rate increases in the water rates could finance the project and that was totally unfeasible and out of everybody's pocket book so that is a major problem. Q. Not to whip a dead horse on the fault issue here. In the event of a breakage of the dam, what's the projected flood point there...have you... do you know just how... A. Extremely limited because of the...if you're familiar with Fritz Creek, it's pretty much a canyon all the way down to the... Q. To the pavement... E Q. But what happens below the pavement? A. We haven't actually plotted the flood plain that is something that will actually be plotted in the design phase. You have to understand, this is a preliminary study and you're starting to ask some almost design type questions and it's very difficult for me to speculate on what the flood plain would be. In the first place, we haven't even decided on the size of the dam. Q. Well, it seems like you would do that before you propose the design. JK: We're not... Q. ....just as far as the risk factor, you know. A. Well, the (inaudible) dam near Susitna is an earth filled dam. It's going to be 800' high...800' high...and that's in the fault zone. Q. That's still under question also. A. The tunnel to Bradley Lake is going to be through three fault zones. Q. That's still in question also. A. Those who build earth filled dams find that earth filled dams are very 0 forgiving of potential faults and potential earth moving. JK: Sir, did you have a question? Q. 60-minutes had a program about them a-year or two ago. ABout the sad state of affairs for our dams, in that the life span of them isn't very long. And there was broken... Q. One in Colorado and one in Idaho in recent years. I saw the results of the Idaho one. I Q. But that wasn't my question. If I could still have my question-..you project Fritz Creek in 2030, is that right? The useful...(tape ran out) I ~~SIDE 2 JK: ...28% in stream flow and we believe that we can get considerably less 3 ~~~than that. We can get it reduced. Q. OK, what I can't understand also is why it does last 50 years in the expense of it and 50 years its going to be out and your man said a while ago that China Poot was an inexhaustable supply, it would last forever. So it seems to me that it would be better to just go ahead with the additional expense that you don't know where you're going to get the money anyway and go with something that will be forever. _ Q. There you go. I Q. ~Well, at Twitter Creek and Bridge Creek it said 10 or 15 years, so are we looking at the same thing in Fritz Creek as far as the life ... actual life of the darn, not the water supply A. Yes. Q. So why not do it right in the first place, do it... instead of doing it I ~ ~~six times like the Spit Road or the post office. 5 ~GRAY: Could you have the engineers address just because there's interest in it, address the China Poot problem and if they are in a position to do that. 1 3~~K: Sure. A. China Poot Lake is in Kachemak Bay State Park and there are severe restrictions to using that as a water supply. It is designated as a recre ational lake. Now. There can be negotiations and so on but in our discussions with the State regulatory agencies, they have lead us to believe that it would be almost impossible for them to approve taking drinking water supply out of that lake. That's one issue. Another is simply the cost and the uncer- I ~ ~~tainties of the submarine type-.the connecting from the other end of the bay to Homer Spit and so it can be further studied, no doubt. Further 'I work done on trying to get approval to use China Poot Lake. It's a beautiful ... a beautiful quality of water. GRAY: Construction wise, how does it compare in difficulty or in ease with the if ~~other proposed locations? A. It would be the most difficult to construct as far as the pipeline is concerned. Getting the water, having a water intake structure in the I ~ ~~lake, is a normal structural problem. But then there are several miles between the lake and the Kachemak Bay and there again, that's an environmentally sensitive area that would be difficult to get permitted. We have been discouraged, up and down the line, from using China Poot Lake. j 3~~K: Excuse me, the gentleman right behind you had a question. ~~~~~~~~~~~~-IO j Q. ~Yeah, we keep talkin' about these water projects. In my opinion the main reason why you're going after Fritz Creek -is because the City needs an additional tax base to pay for it. It's as simple as that. You have no taxable property over in China Poot, you have none up here in the hills except at Fritz Creek. if ~JK: We'll certainly note your comment. Yes, sir? Q. Have you approached the legislature about enacting legislation to get into Beaver Creek or get into China Poot? JK: Oh, we haven't taken it anywhere near that, we're just in the... .and that's' one thing, let-me just... I ~ ~Q. Before I finish then, let me ... why weren't these meetings ... these alternative-i- explored instead of coming out here and it looks like you're already got this thing already made up in your mind, this is where you want to do it. J.K: The ah... I know it looks like that and to a certain extent, that might be true, you know. Q. I believe it is. JK: People have been talking about a new water source for the City of Homer I ~ ~~for I don't know how many years ... a good number of years-.and Fritz Creek always comes on top of the list for one reason or the other so I can't help but say "yeah, there probably ... there might have been a I ~ ~~kind of leading you to an answer thatyou knew you were supposed to get" to kind of a thing, I can't deny that's probably not true. There may have been some other sources that we could have taken a closer look at I ~ ~~and maybe we should go back and take a closer look at some of 'em but chasing after some of them that because of construction difficulties or operation and maintenance difficulties is, I think, chasing after windmills. It...you know, futile exercise that if you take a cursory look at you really can't deny that that's true. And as far as approaching the legislature on any of these, no, of course, we haven't done that. We're not to the point where we' re going to go out and start moving ground I ~ ~~tomorrow, for heaven's sake, we are just to the point where it has become apparent that as Homer grows the need for water is going to grow and something is going to need'to be done. ANd we have taken a look at what other sources U ~ ~~could be used. And we have identified Fritz Creek as what we feel, right now, is one of the most feasible sources, and we are here tonight to see what you folks think about it. We're not going to go out and start building anything tomorrow. Q. I believe everyone in this room is aware of the needs for Homer to have water. And I think you're going to be in tough shape in about three or I ~ ~~four years and that's compounded with the expansion down here. But you had sources of water that isn't on an earthquake fault and where ou 're going to endanger people's lives and everything else and it seems like you haven't considered it, like you're just callous about it. JK: Well, I don't think callous is quite the point but I don't want to argue that with you. You're coqmplaints are noted and we'll take care of what we feel we need to take care of. Q. Well, I still think it should go to the City Council and go to the legislature about exploring these other areas, if you can get in ihere. JK: Your comments will be noted, sir. Yes sir? I Q. ~I just want to mention that our comment about some of theFish & Game on that little creek down there, you know. YOu stated about China Poot and the fisheries people didn't want any part of it... JK: I'm sorry, which creek is this? Q. I'm talking about Fritz Creek.' That you stated that one reason why China Poot wasn't selected was because of the fisheries. Well, what about Fritz' Creek? It's plum full of trout and mink and weasels and otters and every- thing else below the dam and above it. Q. You also have to know it's the last moose habitat area and you're going to get a bitter fight on that one. JK: The ... we had a meeting with Fish & Game a couple of months ago and there were essentially two areas of the fish and game-.there were people from I ~ ~~fish and people from game and essentially our feelings was that ( the fish people did not feel as strongly about the creek as the moose people did. You're right, the moose people were very very upset and concerned. But the fish people felt that the only reason why they're particularly interested in the creeek is because they use it to release smolts during the spring. I ~~Q. I mean realistically you are looking at the last winter habitat untouched. Q. What about the natural fish in th at creek that aren't planted or returned I ~ ~~from the sea? It's plumb full of them. JK: One thing that we need to do is-.it's called an in-stream flow study, and you go out there and you'll actually count the fish and the plant life and the biological life that currently exists in the stream and then you figure out how much water was the minimum flow that's~ required to sustain that The Fish & Game has told us that they're going to require us to do that before they even discuss any further, how much water to release and that's when we'll get into the natural fish that are there. Yes, ma'am? 3 Q. ~How far back i.s that lake supposed to go, once they fill that thing? JK: I can't remember exactly, how far was that, Brent? I ~~BRENT: That depends on the heighth of the dam which goes back to the same problem that we're at of-.it also depends on where the dam is located which site * ~~~is chosen. Q. Say the farthest one back. I ~~BRENT: OK, which would be the up stream one, it would be the highest one, that would go back the farthest and that one can probably go back about a mile. * Q. ~What would that do that high tension power line back there then? A. It shouldn't have any effect on it at all. I ~~It would just span right over it, it's not going to be very wide. It would be less than the spaces between the standards. Yes, sir? EQ. ~~To bring my retrospective-or my understanding of this ... this supply of water you're speaking of, using Fritz Creek, will supply the City of Homer 'til when, under your present projection? I~~A. 50 years. JK: We are projecting 50 years because that is about as long as when you're dealing with these type of things, you can reasonably project. We have three ... there I ~ ~are three population projections for the City, a low, intermediate and a high. And a high is based upon the growth rate we have now continuing just continuing on now. The low is leveling off in about a year or so and the intermediate is continuing like we are now for a few years and then kind I ~ ~of leveling off a little bit more. E~~Q. Which one did you use? 3K: We are using the intermediate one. EQ. ~The intermediate? So the statement of 7 to 8 years doubling population that you quote here has nothing to do with your projections. A. No, that's what the intermediate projections are. Q. That is the intermediate projection? I 3~K: Yeah, it goes on the same-level that we're at now fo'r a few years and then it kind of slacks off after that. EQ. ~Well, I've gotta go back with the re st of them, you're looking at a supply that you say will carry you 50 years, what happens to your supply 7 years after the 50 years when you've doubled that population? Why don't you look at the possibilities of unlimited water than what you're looking at of very limited water? It doesn't... I've had so many figures thrown at me tonight that were pulled out of a computer that, to me, don't seem to be very realistic. Another one is your right of way costs ... I ~ ~not right of way costs, the total cost of your dam upon what were these figures-.today's costs, when you're going to get this funding, 20 years from now, does this include right of way buys, does this include- buying people out in the flood plain, what are we looking at? JK: The cost estimate does not include any compensation to property owners and it's on today's prices and, yeah, you're right, it w~ould definitely go up with inflation. E~~Q. Well, that would significantly increas~e that $5.00/thousand gallon deal then in your. ..and you're calling China Poot a $9.00 saying that's twice but-.you have not come close to computing all the costs in that $5.00 price. I ~A :Well the inflation on the construction costs, affects all types of construction so when you do these kind s, of analyses, you try to bring them all in today's dollars and try to compare it on that basis. Q. You've over allowed then,'is what you're saying? I mean that $5.00 is kind of included some of this stuff...I mean you're saying thatis the high cost...is that? A. No, what I'm saying is that is today's dollars if you could build it today and put it in operation. It's obviously going to be more but as inflation continues, the construction costs on one alternative...they'll go up just as much for other alternatives. Q. The other thing is you do have an estimated cost for buy-out below the flood plain if nothing else, the right of ways and so on...and that whole area is developing south and along that Fritz Creek basin you've got subdivisions going in and so on...that's not going to happen with either (inaudible) with undoubtedly the technology by the time you're there, has made giant strides already. Undoubtedly by the time this thing is ready to fly, we'll be talking lowering costs. A. Well, if you're talking about buy-out costs, the total assessed value is strictly ..... Q. No, but I'm saying compare that to either to your desalinization plant and the technology bringing that cost down which is I think probably reasonably expectable, or, again, an unlimited source from China Poot. JK: Well, the point that we did not include...that this...the figures are $2.24/thousand gallons if at the more realistic flood level or dam level for Fritz. But at $4.09 is for the 60% down stream release which we don't believe we'll have to meet. Thepoint that we did not include, compensation ( costs, right of way costs this kind of thing, in that...is well taken, we did not do that. Q. Well, I guess I'm also concerned as I think Bob said, in 2010 we may find that estimate is not realistic and we're gonna be doubling it and increasing rate in math...you're squaring your population every year...is going up by that much more, and when you do run short, where do you go from there? Why not go at whatever the cost, again for an unlimited, or a relatively unlimited source or can you not...may I ask you this, can you expand a desalinization plant? That may ultimately be the answer for this area. Is it...is the technology such that you can add another unit at a later time, as you need more water? A. Desalinization happens to be something I've worked in for about 15 or 20 years. There have been great strides made in desalinization, they are using it to desalt sea water in Saudi Arabia where...where there is an unlimited amount of money available and the other alternative is distillation and they're reducing 90 million gallons a day in Jeddah Saudi Arabia. Now there they have warm water and they have a great deal of money and they're extremely energy intensive. That pressure has to be at 800 pounds per square inch and the membranes are so tight that it just trickles through the membrane so you have to pump a great deal of water past these membranes at high pressure. And as the temperature of the'water gets lower to the temperatures that you'd find here, the efficiency goes down to about 50% normal efficiency. So it's capital intensive and that the electrical energy costs here in Homer, it would be just very very expensive to operate. The technology is here but the cost is just fabulous. So there's no doubt that it's an option but.... -14- A. But to make that feasible, you have to get the energy costs down and all the projections for electrical energy costs and all of the projections for Chugach are going up. They don't look like they're gonna be lowering their rates for some time. U Q. ~Then perhaps some more intensive study at China Poot Lake would be the... that's a long-term, thing and ultimately we're going to run out of water in 2040, if not 2030, we're going to be scrambling this whole show again I ~ ~~and I know an underwa.ter aqueduct was discussed in town 20, 25 year ... 15 years ago atleast and the cost at that time seemed astronomical but they'd be darn well underway to being paid for by today and we wouldn't be facing this rolling effect that now we're looking at some other creeek or...I1 just wonder if we shouldn't take a longer look down the road rather than just 50 years because I'll bet we'll all-.some of us will still be around 20 years from now... A. Can I ask you a question. How do you think public reaction would be to the thought of running a pipeline across Kachemak Bay that all of the oil companies have talked about doing. Q. What's a water line going to do when it breaks down there? There's a power * ~~~line there (simultaneous speech -inaudible) JK: Are there any other'specific questions anyone has? Yes, sir? I Q. ~I have one real short comment.' I think you're barking up the wrong tree anyway because if you had your dam there built last year, that thing would be absolutely empty. You go up there right now and see how much I ~ ~~water's in there, or two days ago before it rained. Thre's no water up there-.what do you do on a year like this? You're gonna be out of water before 1985. I think it's a wrong move. There's no water there unless it's a real rainy year. Q. There was no water there last February. Q. And I'm not a computer but I've seen it with my own eye balls ... (laughter) I Q. ~I wds wondering since why the focus was on Fritz Creek that you didn't come out there to us at McNeil Canyon School, a lot of people that came in here. JK: Well, the... no, you-do have a point there, but it doesn't effect simply Fritz Creek, it affects the City of Homer as well. I f~~. Look around this room. How many people are here from the City of Homer? (simultaneous speech, in audible) JK: Well, I want to thank everybody for coming. Feel free to stick around and ask specific questions of whoever if you need information or if you want more information on something, we'll help with that.too. I think I got a pretty good idea of what you want more information on. SEC.' 27.4 27.4 Response to Public Workshop I ~~~General I ~~~This meeting was a workshop for the purpose of soliciting public input but was not a formal public hearing. It was felt that public input 3 ~~~would be more candid in this type of a setting. Therefore, the usual formality of statement of the participant's name and address was not I ~~~adhered to. The questions or responses where germaine to the study, are numbered and I ~ ~~identified by enclosing the text with a bar along the right-hand side of the minutes. These responses are then made in the same order. Responses U ~~~1. Mr. Robert E. Gray expressed considerable interest in the study and was specifically concerned with the possibility of the utilization I ~ ~~~of China Poot Lake as an unlimited source of supply of water. He further followed up his workshop comments with written comments 3 ~~~~expressing his support for additional consideration and study of the feasibility of China Poot Lake as the source of supply. This 3 ~~~~study gave a preliminary assessment of China Poot Lake in Section 4.2. 1 ~~~2. This discussion involved Beaver Creek to the northeast of Homer, as a source of supply. Contrary to the statements made as to the size I ~~~~of the Beaver Creek drainage basin, it drains an area (10 sq.mi.) smaller than Fritz Creek and has a significantly greater area used as a moose wintering habitat. The Beaver Creek assessment was covered in Section 7.2, part a. 3 ~~~3. The preliminary soils assessment was covered in Section 8.0, Regional Geology; and as site specifically for Bridge, Twitter and Fritz Creeks in Sections 9.5, 10.4 and 11.4, respectively. Only a 27-1 soils reconnaissance was authorized by this contract. Detailed soils borings and logs would be accomplished after a site is selected and prior to design. 4. The expansion of the Bridge Creek facility has been discussed in Section 9.0. 5. The questions on flow rates, in-stream requirements and hydrology in general were answered in detail in the minutes of the workshop. In addition, hydrology had been addressed in Section 6.0. 6. The present'and projected demand on the Homer water system includes commercial (and canneries) demands. This demand was addressed in Section 2.0. 7. The general question on seismic faults received considerable discussion and received lengthy discussion at the workshop. The subject of earthquakes, faults and potential dam failure can be more subjective than objective. The subject had been reported in Section 8.4. 8. Financing was discussed in Section 25.0. 9. The detailed identification of a flood plain is not a part of this preliminary study, but would be part of design after a site was selected. 10. This discussion is a follow-on of workshop discussion item number 7, on seismicity. Again, refer to Section 8.4 of the report. 11. Comment noted. 12. This is a continuation of workshop discussion item number 1. 13. Comment noted. 27-2 14. Comment noted. 15. Comments noted. 16. Comments noted. See also Section 27.1 for Fish & Game meeting comments. 17. See report Sections 11.0, 12.0 and 13.0. 18. Discussion on population and usage projections had been covered in Chapter 2.0. 19. Costs of alternatives had been discussed in Chapters 14.0 and 22.0. 20. Comments noted. 27 -3 U I I I 1 APPENDICES I I I I I I I I I I I HOMER PROJECT CONSTRUCTION COST ESTIMATE 2300 A-F 4000 A-F 5800 A-F I Unit Price Quantity $ Quantity $ Quantity 5 1.0 DAM 1.01 Diversion and Care of Water LS 1 70,000 1 70,000 1 70,000 1.02 Clearing Including Reservoir Area 4,1.0.00/ac 92 377,000 170 697,000 267 1,095,000 3 1.03 Foundation Preparation 5.00/cy 190,000 950,000 265,000 1,325,000 300,000 1,500,000 1.04 Sheet Piling 48.00/sf 37,000 1,776,000 53,000 2,544,000 68,000 3,264,000 1.05 Filter Cloth 0.37/sf 277,000 103,000 300,000 111,000 330,000 122,000 1.06 Drain Wells 80.00/if 2,250 180,000 3,050 244,000 3,600 288,000 1.07 Random Fill 5.57/cy 90,000 501,000 164,000 913,000 225,000 1,254,000 1.08 Till Fill 11.00/cy 200,000 2,200,000 302,000 3,322,000 408,000 4,488,000 1.09 Upstream Sand Shell 8.00/cy 179,000 1,432,000 235,000 1,880,000 298,000 2,384,000 * 1.10 Filters 16.80/cy 138,000 2,318,000 192,000 3,226,000 246,000 4,133,000 - 1.11 Riprap - l t 25.80/cy 60,000 1,548,000 62,000 1,600,000 65,000 1,677,000 ! :j1.12 RAccess Roads 0307,000.00/mi 1.5 461,000 1.5 461,000 1.5 461,000 ' 1 0SUBTOTAL 11,916,000 16,393,000 20,736,000 2.0 SERVICE SPILLWAY 2.01 :-, Clearing (Included in Above) ! i; 2.02I - X Excavation 0 -- 5.90/cy 7,000 41,000 7,000 41,000 7,000 41,000 2.03-:- Backfill 10.00/cy 9,720 97,000 9,720 97,000 9,720 97,000 2.04 Concrete Outlet 500.00/cy 50 25,000 50 25,000 50 25,000 2.05 Concrete Inlet 600./y 65 39,000/cy 65 39,000 65 39,000 2.06 Concrete Conduit 500.00/cy 1,250 625,000 1,250 625,000 1,250 625,000 2.07 Concrete Pipe 200.00/ft 200 40,000 200 40,000 200 40,000 2.08 Steel Liner 3.00/lb 125,000 375,000 125,000 375,000 125,000 375,000 SUBTOTAL 1,242,000 1,242,000 1,242,000 3.0 EMERGENCY SPILLWAY 3.01 Clearing (Included in Above) 3.02 Excavation, Unclassified 3.80/cy 1,900 7,000 1,900 I 000 1,900 7,000 3.03 Riprap/Gabions 25.80/cy 555 14,000 625 16,000 625 17,000 3.04 Filter Cloth 3.04 Filter Cloth nr0.37/ft2 5,000 2,000 5,500 2,000 6,000 2,000 3.05 Concrete 500.00/cy 375 188,000 375 188,000 375 188,000 SUBTOTAL 211,000 213,000 214,000 _I �ii ~~Ii~~~~~~~~ - U HOMER PROJECT CONSTRUCTION COST ESTIMATE Page 2 Piag 2 2300 A-F 4000 A-F 5800 A-F Unit Price Quantity $ Quantity $ Quantity $ 4.0 OUTLET WORKS 4.01 Excavation 5.90/cy 18,000 106,000 18,000 106,000 18,000 106,000 4.02 Backfill 10.00/cy 14,000 140,000 14,000 140,000 14,000 140,000 4.03 Concrete Outlet 500.00/cy 50 25,000 50 25,000 50 25,000 4.04 Concrete Inlet 500.00/cy 75 38,000 75 38,000 75 38,000 4.05 Concrete Conduit 500.00/cy 1,900 450,000 1,900 950,000 1,900 950,000 4.06 Concrete Plug 400.00/cy 25 10,000 25 10,000 25 10,000 4.07 Gate 15,000.00/LS 1 15,000 1 15,000 1 15,000 4.08 Steel Pipe 55#/ft. + 5000 lb. of supports 3.00/lb 38,000 114,000 41,000 123.000 45,000 135,000 SUBTOTAL 1,398,000 1,407,000 1,419,000 GRAND TOTAL 14,767,000 19,255,000 23,611,000 I I I I I I I I ~~~~~~~~~~~APPENDIX A DETAILED CONSTRUCTION COST ESTIMATE a I I I I I I I W.T.P. SITE IMPROVEMENTS Total Unit Quantity Unit Price Amount Yard Piping: 16" D.I. Infl/Effluent to Storage 100 LF $ 75 $ 7,500 12" D.I. Overflow & Sludge 950 LF 55 52,250 8" D.I. Storage Tank Overflow 100 LF 30 3,000 16" BFV 3 EA 2,500 7,500 12" GV 3 EA 2,000 6,000 8" GV 1 EA 1,000 1,000 San. Sew.; Septic Tank & Drainfld 1 L.S. 5,000 5,000 Subtotal 82,250 Miscellaneous Fencing 1,000 LF 20 20,000 Primary Power, Incl Poles & Trans. 3,000 LF 25,700 Telephone (wire only) 3,000 LF 1 3,000 Sludge Lagoons: Excav. & Constr. 15,000 C.Y. 5 45,000 Asphalt Paving 330 T 30 9,900 Subtotal 103,600 Total Site Improvements $ 185,850 TRANSMISSION MAIN Dam to WTP: 16" D.I. Pipe 5,000 LF 75 375,000 WTP to East Road (@ Fritz): 16" D.I. Pipe 2,900 LF 75 217,500 East Road to Kachemak: 16" DI. Pipe 27,600 LF 75 2,070,000 45� Bend, 16" 5 EA 600 3,000 22-1/2� Bend, 16" 4 EA 600 2,400 16" BFV 16 EA 2,500 40,000 Blow-Off Valve 5 EA 2,000 10,000 Hydrant Tees & G.V. (No Hyd.) 18 EA 1,500 27,000 Hydrant Assy., Incl. Tee & GV 21 EA 2,500 52,500 Pit Run Gravel 19,500 T 4 78,000 Asphalt Patching 2,000 % 30 60,000 Transmission Main Total $2,935,400 WATER TREATMENT PLANT Total Unit Description Quantity Unit Price Amount Building Shell $ 240,000 Internal Rooms 28,600 Soil Allowance 16,000 Heating 24,000 Dehumidifier 4,700 Lighting 12,000 Wiring & Acc. 31,500 Misc. Equipment 2,100 Lab Equipment 3,000 Filters & Instrumentation 350,000 Insulation 25,000 Chemical Feed Equipment 41,225 Pumps 13,989 Air Compressors 4,400 Aux. Generator 25,000 Storage Tank (Fuel) 5,000 Plant Piping 161,360 Pipe Insulation 11,600 Equipment Installation 77,100 Grating 12,750 Freight 30,000 Storage Tank 0.5 MG 313,740 Level Controls 1,500 Telemetry Equipment 2,700 Static Mixer 8,000 Flow Meter & Tube 2 Ea 7,200 18" Isolation Valves 6 Ea 5,270 Misc. Valves 8,000 WTP TOTAL $1,443 234 APP: B CONSULTANTS A B William L Shannon, P.E. Stanley D. Wilson, P.E. I SHANNON & WILSON, INC. Geotechnical Consultants 2055 Hill Road, P.O. Box 843 * Fairbanks, Alaska 99707 d Telephone (907) 452-6183 March 28, 1983 :-'r_,,VE' - KP-522 . 1933 Crippen Consultants 916 Plaza 600 Building Seattle, WA 98101 Attn: Mr. Brent Leslie RE: PRELIMINARY PROPOSAL FOR SUBSURFACE EXPLORATIONS AND LABORATORY TESTING, EARTHFILL DAM, HOMER, ALASKA Gentlemen: In accordance with your request of March 22, 1983, we are pleased to submit our preliminary proposal for conducting subsurface explorations and laboratory testing for the proposed earthfill dam on Fritz Creek near Homer, Alaska. The purpose of our studies would be to develop information to assist you with the design of the proposed facility. We understand that the proposed dam will be approximately 100 feet high. The purpose of this proposal is to provide you with a rough estimate of the costs involved in an exploration program for the proposed dam so that you can present this estimate to the City of Homer. The estimated costs in the proposal are slightly modified from those given to you verbally on Mlarch 24, 1983. I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Based on your comments, we understand that there is no bedrock exposed in the area, and that you do not anticipate encountering rock in the exploratory borings. For purposes of preliminary estimating, we under- stand that you wish to explore the site with three borings to a depth of 100 feet, two to a depth of 75 feet, and two to a depth of 50 feet. The borings would be sampled with split-sponn drive samples. If weathered bedrock is encountered above the target depth of the borings, it would be penetrated as deep as possible with the auger. Resistant bedrock Ronn D Aboot. PE Vice President and Maqanan"r '7 ~~~March 28, 1983 K-2 3 ~~~~Mr. Brent Leslie Page 2 could be diamond cored, but our estimate is not based on the borings requiring diamond coring. 3 ~~~~The drilling and sampling would be observed by an experienced engineer or geologist from our firm, who would visually classify all samples in 1 ~~~~the field and prepare descriptive soil logs for all borings. The * ~~~~samples would be returned to our Fairbanks laboratory for tests that would be pertinent to our studies, such as natural water content, density, grain-size gradation, organic content, and Atterberg limits. 3 ~~~~In-hole permeability testing, such as falling head permeability tests or packer tests, would be performed in each boring as appropriate. In addition to the test boring work, backhoe test pits would be excavat- ed 6nd sampled at selected locations to explore surficia'l soil con- ditions. 3 ~~~~The locatio ns and elevations of all borings would be. spottead on a map by our engineer or geologist after they had been drilled. This would be 3 ~~~~accomplished by tape and hand level-referenced to existing features and an assumed elevation. If precise surveying is desired it should be 3 ~~~~accomplished by a professional surveyor. The cost for precise surveying has not been included in our estimate. I ~~~~A report would be prepared which would sunimarize the geology of the area, field explorations, subsurface conditions, laboratory test re- 3 ~~~~sults, and material properties and engineering parameters. At your request, we have not included the cost of detailed engineering or design 3 ~~~~stu dies in our estimate. 5 ~~~~We understand that at present there is no road access to at least some of the boring locations, and that a helicopter-portable drill would be required to access these locations. However, due to the large cost for 1. ~ ~~heavy-lift helicopters, it may be cost effective to have trails made to March 28, 1983 KP-522 Mr. Brent Leslie Page 3 the drilling locations so that a track-mounted drill rig could be used. Two estimates have been prepared, one for a helicopter-portable drill rig, the other for a track-mounted drill rig. The difference in esti- mated cost between the two reflects not only helicopter costs but also the greater production rate of the larger track-mounted drill rig. The cost of trail building is not included in our estimate. SUMMARY OF ESTIMATED COSTS HELICOPTER-PORTABLE DRILLING OPERATION Mob-ilization/Demobilization $ 11,000 Drilling, Sampling, and Logging of Borings 39,800 Down-Hole Testing (estimated one day per boring) 20,600 Helicopter Support 35,200 Backhoe Test Pits (estimated two days) 2,800 Laboratory Testing 4,900 Report Preparation 8,400 Estimated Total S122,700 SUMMARY OF ESTIMATED COSTS TRACK-MOUNTED DRILLING OPERATION Mobilization-Demobilization $ 11,000 Drilling, Sampling, and Logging of Borings 23,600 Down-hole Testing (estimated one day per boring) 22,700 Backhoe Test Pits (estimated two days) 2,800 Laboratory Testing 4,900 Report Preparation 8,400 Estimated Total S 73,400 At the present time we are negotiating a scope of work for geotechnical investigations for the Bradley Lake Hydroelectric Project, which would be based in Homer. This project may involve drilling this summer, which March 28, 1983 K-2 Mr. Brent Leslie Page 4 3 ~~~~could reduce the mobilization costs on your project if both projects * - ~~~could be performed in the same time period. I ~~~~We understand that this proposal is not a binding agreement at this time, but is merely required in order to seek funding for further design ft ~~~~studies. When a decision is made to proceed w~ith further stud'ies, we will be pleased to prepare a detailed estimate. At that time we could 3 ~~~~help you develop a detailed scope of work, and would assess the impact * ~~~~ of site accessibility, Anticipated subsurface conditions, and logistics on our estimate. We would also be pleased to prepare a proposal for IT ~ ~~~assistin~g you with developing engineering and design recommendations for the project. If you have any questions or comments, or wish to discuss alterations to B ~~~~the proposed scope of services, please contact either John Cronin or me. We look forward to the opportunity to work with you on this project and I ~~~~appreciate your continued confidence in our firm. Si ncerely, SHANNON & WILSON, INC. ft B~~~~y7?LTh Q & Rohn 0. Abbott, P.E. I ~~~~~Vice President and Manager JEC/RDA/l kd APP.C 3.iFE 0% FLJILLi L / BILL SHEFFIELD, GOVERNOR 619 WAREHOUSE AVE. SUITE 210 DEPARTMENT OF NAfIURAL RESOURCES ANCHORAGE, ALASKA 99501 PHONE: (907) 276-2653 DtIVISION OF PARKS MHay 5, 1983 Re: 3130-4 (Olympic Associates) - MAY 12 1983 John Lenart Project Engineer OLYMPIC ASSOCIATES C0. Olympic Associates Company SEATTLE P.O. Box 9310 Seattle, Washington 98109 Dear Mr. Lenart: We have- reviewed the proposed Fritz Creek Water Project for Homer project and would like to offer the following comments: STATE HISTORIC PRESERVATION OFFICER There are currently no known cultural resource sites in the Fritz Creek dam and reservoir area. However, we feel the area has high potential for having such sites. The history of cultural resource site survey in the Kenai Peninsula is such that the concentration has been on the coast where the larger, more easily accessible sites are. There have been no surveys up the rivers and major creeks. These waterways are natural access routes to the uplands for poten- tial hunting. We would expect to find sites associated with this type of activity along the waterways and in the uplands. We recommend a preconstruction cultural resource survey of the project area (per 36 CFR 800). Should you have any questi napease contact Diana Rigg at 264-2132. Ty/L. _illiplane '\e State istoric Preservation ffcer STATE PARK PLANNING No probable or significant impact on existing, proposed or potential state park or other public recreation values. John Lenart Page 2 - LAND & WATER CONSERVATION FUND GRANT PROGRAM No comment. Sincerely, Neil C. Joha 4en Director DR:clk 3. AL'-.5}L~ STATE LA.: .'$ I~~~~~~~~~~~~~~~~~~~~~~~4 S a>> ' ,' V'r''> 2 - I I I I I FIGURES I I I I I I V I I 3 I I 1 I J -< Crek - -oxc flap3W~I~yS -& 7~ < /KEY MAP /i -~ - ) I aric~~~~~~iko~~~~~ / -, ~~~~~Alaska J/ 7 './-.j. Kenai i~~~~~~~~~~~~~~Ivk ,O,.E~i ~ IBEAVER CREEK - djBRDELAE Anchor P06L D i~.. ~~AJ7n .~ Landing j- Begar- Islan RCPTTO L~~~~~I LEGEDAMST ~~~~~~~~~~~TWITTER~CE- K\" .*uyng*OHRTCNLG jBRIDGE ~~~~~~~CREE PR~ER O*CHINAPIOTLATE~ION5'ILE ANCHOR~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~FG R1E-1 ~~ iO it ~~~~~~~~~~~~~~~~~~~~~~WTEMPRASOURCE STUDY a~~~~~~~~~~~~~~~ CRPEN CNUTAT, INC.FLW AG -),, - -_ m - - - - -~ - 3.0 AVERAGE DAILY DEMAND, MGD (EXCLUSIVE-OF DEMAND OUTSIDE CITY LIMITS) 2.5 - 2.0 - ~~~i~~~~~b~~Bil cr1.5 LU~~Ln I- 1 .0 n~~~~~~~~~~~ io 1914 1978 1982 1986 1990 1994 1998 2002 2006 2010 YEAR ! _ _ _ _ _ __ _ _ _ _ - _ - _ 3.5 AVERAGE DAILY DEMAND, MGD (INCLUDES DEMAND OUTSIDE OF CITY LIMITS) 3.0- ,.5 ,- 2.0 ~~~~~~~~~~1.5 r~~~~ 1.0 2 '1 0.5- 11) 1974 197 198 2 1986 1990 1 994 1998 2002 2006 2010 I _ _ m m- -m -- _ m - - - m m 6.0 MAXIMUM DAY DEMAND, MGD (EXCLUSIVE OF DEMAND OUTSIDE CITY LIMITS) 5.Ob. 4.0- 3.0 ,. 32.0 - 0 1.0 - -n 0 1978 1982 1986 1990 1994 1998 2002 2006 2010 YEAR - mml �sme -a - -la 7.0 MAXIMUM DAY DEMAND, MGD (INCLUDES'DEMAND OUTSIDE CITY LIMITS) 6.0 - 4.0 - 3.0 - 2.0 - 1.0 1978 1 982 1 l86 1d990 144 148 2dO2 2606 2010 YEAR LUA'nP SURFICIAL GEOLOGIC MAP * ft 22W. ~~~2o' 5945 ~EXPLANATION 7' ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Flood-plain deposits 21D 23 Afay yield 3 qp- qf tvater La shallow well*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ciyel SU..ofw~* t aaowwel / '~~'~ silt, .ewd, ewd growl iw cha~~~~~~rn~et., peU~~~p floors ead law turroT.ceLS T.55 Alluvial-fan deposits~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Aluil-a epst to ehallo. wefle j ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Eevate ia itadbahdpst B ill ead orgoawic wotrial adjacent toLa .le*aLae weU-eortsd ."a ~ ~ ~~~~~~~~~~~ bach gravel and eowd on Home, Spit; poet glacia. Yields 3f: enli eetiwe aw.4 brackiak water on Ike Ho..er Spit 4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~oly**in ad rckshwaeranth Hme Si 4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1. Rida. W~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Qt1..b'i .deoiemr ta O.ttic.Palca t"~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .... ..i Gih adolatriove depositi, csito oar Qg 2. subunit 1, deposit& more thai, f0feel thick. Priwcaipoth claym and cotluvium. Occur,- higher ox benches. Virt-ally not iwater bearing C Saw~~~~~~~~ ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~40 Uniffrn itd �deposits Sandandgrael o BanesandCobb (1950); po-1placial. may 52i Ip ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~co,1tain pr*-Naptown glacial drift ..dopaeit-ed i, Napio-wa K \\ I Ii.... Yield S La 10 gpa. of looter La eholtoa, welts~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~rta"tie.Yel t 1 p"a tot~ to'sef U~~~~~~~~T4S T. 65S. Morainal deposits Mil, ice-conact. and outasok-ot rea. eoie omddrw tast glaciatioat of H~omer area. Poor aeberwfomtw except iw local sand and graelI beds where yields of 10 to B z gpp may be obtaiwed .0~~~~~~~~~~~~~~~~~~~~- - J - - ~~~~~~~~~~~~~Kenai Formation / I ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Ia*erbedded poorly consolidatred *Gui~w.eiltstwe w ei bad. febit.wwu coal awd ligwite. rho most xw* S 7 cad beet potewtial aquifer iw the Hoiwer ores~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~an es ptetalagierI.th o- ae ~~-H mer,~�~3~ASA D ase wherie an ip fareds n~~~~ I. * * a. Lake ~~~~~~~~~~~~~~~~~1o~~~~o~~~e~~~~s - - - - Wellortautbcle~~~~~~~~~~autaproimtelyloa eluga Radio- 41'a~~~~~~~~~~~~~~~~~~~~~e~~~a~~~ Number eoroeepowde 20 t~~~~~~~~~~~~~~~~~Arow *a-roao.. ion teatde , t~~rw fiji.~~~~~~~~~~~~~~~~~~~~~~k Wri USeoloel Sre pohrph Gooycte' .sanot, 11959 qo~~~~~drsngte$ t94a1952 SCALE 1~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~63 360 and Ker~~~~~~~~~~~~~~~~~~ltroni 119641opos o he t tx '~ ~ ~~~~~~ ~~sidfo U Souce Wailer, co R5M,mTprh- Geology2 Afde S, and Cobrbs D.195996 PROCESS FLOW DIAGRAM - SEAWATER REVERSE OSMOSIS CON1VERSION MOTOR ENERGY RECOVERY TURBINE HIGH PRESSURE RO PUMP 1 PRODUCT TRANSFER PUMPS ID STORAGE CARTRIDGE FILTERS f PERMEATOR RACKS CONCENTRATE RETURN TO SEA Source: DuPont Corp., 1981 __ Source: DuPont Corp., 1981 720 640 - 560 U- )0 480 0 .- u- 400 I z 320 z '240 160 80 0 O I N I D I J- F I MI A I M I J I J I A I S MONTH FIG. 6.1 CITY OF-HOMER, ALASKA PERIODS: 1966-73, 1979-81 WATER SOURCE STUDY (Anchor River near Anchor Point) MEAN MONTHLY FLOW ANCHOR RIVER PROJ# 0024 APPV. DATE 10-82 I]~ ~ CRIPPEN CONSULTANTS, INC. SEATTLE 700 600 : I Soo 500 ,. 400 -- --\ . O -- 300 200 " i8 I ... - ARecorded Simulated "',, !. I ' 100 .-.L - .5 0 10 20 30 40 50 60 70 80 90 100 EXCEEDANCE PROBABILITY FIG. 6.2 CITY OF HOMER. ALASKA WATER SOURCE STUDY FLOW DURATION CURVE ANCHOR RIVER PROJ-s 0024 APPV. DATE 9-82 oW CRIPPEN CONSULTANTS, INC. SEAfTLE 20 *0 15 0 -J Ir 10 O < 5 I w 0 O'N' D''F'M'A' MJ 'J jA'S MONTH SIMULATED FLOWS PERIOD: 1949-72 FIG. 9.1 CITY OF HOMER, ALASKA WATER SOURCE STUDY MEAN MONTHLY FLOW BRIDGE CREEK PROJ# 0024 APPV. DATE 12-82 0P]~[] CRIPPEN CONSULTANTS, INC. 3~~~~~~~~~~~~~~~~~~~"ll"~ SEATTLE 1100 1000 900 1 I 800 w ~~~~~~~~~~I w ~~I U) I ~~~~u- 010) 700 (:/.. J1(3 CFS / 0 ,e / ecuuals .66 NGG 600 I I.~~I I 500/ /Massi cur're of inflow // 300 J1 A S 0 N D J F M JM CITY OF HOMER, ALASKA WATER SOURCE STUDY BRIDGE CREEK MASS CURVE - 1950-51 PROJ.- 0024 APPV. DATE 11-82 -.MdYbb- CRIPPEN CONSULTANTS. INC. 3~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SE A I T I .8 .7 .6 80 90 100 CONFIDENCE LEVEL, % 700 GPM.lInstream flow FIG. 9.3 CITY OF HOMER, ALASKA WATER SOURCE STUDY BRIDGE CREEK WATER YIELD PROJ# 0024 APPV. DATE 11/82 wlIor CRIPPEN CONSULTANTS, INC. - _ S F A T r L E *^~~~ ~~6.0- I 5.0 CD INTERMEDiATE GROWTH IN POPULATION 4.0 W/ INDUSTRIAL INCREASE 0 a~cl --- INTERMEDIATE GROWTH IN POPULATION 5li : , 3.0 UJ <( i ,| Fritz & Bridg e Cr., 2.45 MGD, 95% confidence r<: (Based on 60% flow reduction for instream uses.,) -- 2.0 ! i J ./0 Twitter & Bridge Cr., 1.86 MGD, 95% confidence I 1.0 31J~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~ ~Bridge Creek yield, 0.69 MGD, 90% confidence P~c_ -. -' Bridge Creek yield, 0.58 MGD, 95% confidence 0 3* 198-0 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 YEAR FIG. 9.4 i AVERAGE DAILY DEMAND, MGD (Inclusive of demand outside city limits) CITY OF HOMER, ALASKA WATER SOURCE STUDY U . .NOTE: CURVES INDICATE MOST PROBABLE DEMANDS TO BE EXPERIENCED. mD=~~~~~~~~~~ . . ~~~~~~~~~~~~~~~~~YIELD vs. DEMAND _I, PROSJ 0024 APPV. DATE 1 1-82 0i ~P CRIPPEN CONSULTANTS, INC. SEATTLE 37ff ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~7 7'w C, I s~I;M-G.C WLVI IT If I; -- .---- ~~-~- -i- - - - , _ I 1 i I i I ( N ~ ~ su/I I .1 I ---- I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~VT I I' 0tJI W,57Z Lc ~IZ, J .4 - - - - i,~~~~~ I~I KiLI- IT C/~ I I_ nrrv'' jvc~LL? '2. StECPz -- [~VLL 'Si St 2WA A L�f 1A! Vcnr f' So0' AcM12=VTrAl Existing Crest El. I: � - nwrurL ~~~~~~~~~~~~~~rX Ei. 9,4 99,.t& -9soff I AOC*(AZ ~' a. seas' -----**--*----- UNDESIRABLE RE-ENTRANT ANGLES -.~~~~~~~~~~~~~~~~~~~~E Lr I ICW~~~~~~~~~~~~~~ ~~ADDITIONAL FII L U~~~~~~~~~ ~ I ------------ ?JLOCS- �r0 DICIIce I164" -04,Wrd;-1Ck CA4.15&IC SC/tCLS 1o V a rS&C MAXIA (MUM 5B? C7/ON 'aQs7 ffcr.!%US * ~~~~~~~~~~~~~~ADAPTED TO SHOW PROPOSED METHOD OF RAISING EXISTING DAM. FiG. 956 CITY O F HOMER, ALASKA BRIDGE CREEK DAM Adapted From CH2M Hill (Alaska): PROJ#0024 APPV. DT1t Dwg. #3017-15, May 1974CRPECNUTAT.I. -~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~- Ir'~rrRevision 1, March 1976CRPECOSLATI. 1 t~~~~~Z~~~-3SU~~~~~C~~~- ~~~~U~~~~Y~~~LL ~~~~~YM~~~/C~~~~X /UUS11~~~~~~~~~PAT t _ 7 .I c 6 u- I_ LL O 3 z I z~- 2 1973 O T.. 1-- _.-; ..... AN C 'RI'' --- "~" "-~' ' ' ~ ' ~:F _ .- _ _ _ 0 A S O N D J F M A M J J A S O N D J F M A M J J A S 1971 1972 1973 MONTH -TWITTER CREEK .......... ANCHOR RIVER FIG. 10.1 CITY OF HOMER. ALASKA WATER SOURCE STUDY MONTHLY FLOWS, ANCHOR R. & TWITTER CR. PROJ* 0024 APPV. DATE 10-82 CRIPPEN CONSULTANTS, INC. i ~~S E A T T L CD 10.0 / C 5.0- 4 -0 - X lU 4.0- xO - 2 3.0- 2.0- x x/ 1.0 x 0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 T.WITTER CK NR LOOKOUT MTN RUNOFF (CFS/SQMI) FIG. 10.2 CITY OF HOMER, ALASKA WATER SOURCE STUDY DISCHARGE MEASUREMENTS ANCHOR R. vs. TWITTER CR. PROJ# 0024 APPV. DATE 10-82 CRIPPEN CONSULTANTS, INC. Ui SEATTLE I~~~~~~~~~~~~~~~2 U~~~~~~~~~~o 1~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~17' U ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1050 OUTLET SERVICESPILLWA ~~~~~~~~~~~~~~~~FI.1075.35 3 WAT~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~SIER SPUICE STUDY 3 FRITZ&~~~~~~~~~~~~~~~~~~~TWITTER CREEK DAMS 5 7 5 ftQ scaAorolmma2 scal USG f~flagee seol RIP NCO ULAT. 51ANC.a l t10.0 . . x 7.0 - co 8.0- z: 7.0- u 6.0- Cc x * 5.0- 0 1.0 2.0 3.0 4.0 5.0 8.0 7.0 8.0 9.0 10.0 FRITZ CREEK RUNOFF [CFS/SQMII FIG. 1 1.1 CITY OF HOMER, ALASKA WATER SOURCE STUDY DISCHARGE MEASUREMENTS FRITZ CREEK vs. ANCHOR RIVER PROJ* 0024 APPV. DATE 10-82 [FrI D { CRIPPEN CONSULTANTS. INC. 3S E A T T LE L. 7000 1__ 6000- . co O Z O 5000 z 4000 O FIG. 15.1 C)i- R~OPTIMUM SIZE OF RESERVOIR-t. PROJ# 0024 APPV. DATE 3-83 CRIPPEN CONSULTANTS. INC. ~~~CM a10 r- < . LL~ wL z -w~~~~~~~~~- LU0Z~~W .Q)7 *~~~~~~~~~~~~~~~~~~~~~~~~ IC � ~~~~ ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~r Co I~~~~~~~~~~~~~~~~~~~~L 0 (0~~~~~~~~ <o C~~~~~C Co~~~~~~_ lool-ejou lownlOA J10AJOSOU 0 w Co~~~~~L LO~~~~~~~~~~~~~~~~~~~~~~~~~~~~I F- C ~~~~~~~~~~~~~~~~~~~~~~~~~~~co ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~CD ~~~~~~r~~~~~~~~~~~f~~~~ M-~ CD- ~~~~~~~~~~~~Co 0A E~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~CD 0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 0~~~~~~~~~~~~~~~~~~~~~~~~* CD E~~~~~~~~~~~~~ I / ~~~~~~~~~~~~~~~~~~(D ~~~~~~~~~~~~~~~~~~~CD / ~~~~~~~~~~~co LO~~~~~~~~~~~~~~ CO j C] D N PII z~~~UEIRRPORPIST,7 4<0/~~~~~~f 800 700 / , 1 .00 cc oI * i: R 6 300 7 I /~/7 200 / 100 _ 3(9 P~~~~~~~~~~~~~~~~~~~~~~~~~ROJ# 0024 APPV�fj PsP/.A283 ./ CRIPPEN CONSULTANTS. INC. SEATTLE 1~~~~~~~~~~O 0 I C"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~I U~~~~~~~~~C 0 0C00CC I ~~~ ~~~~~~~'4 WATER SUPPLYTO in PLAN CITY OF HOMER 100t 200 Soo 1.000 Approximate Scale in lost: 0.Crest 3 Da~~~~~~~~~~~~~~~~~~~~~~~~~~~~~m axis D am crest - Normal full pool Cas la adfle V . . Grassed downstream slope 5 ~~~~~~~~~~Riprap on fltter cloth 3 Minimum pool TI I Fine clean sand fillersRadmtl ~~Excavated ground Surface - 'I/'T'Y/J$.~~~~~'//I j5.O' 5.0' ~FiG.- 17.1 '-~Excawt~d groud SurfaI Filter cloth Exitin grundsurace 10.0' thrck till blanket Sheet, piling I15fwelWATER SOURCE STUDY Drain well FRITZ CREEK DAM TYPICAL DAM SECTION PLAN & SECTION 3 PROJ# 0024 APPV @x~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~4 DATE 02-83~~~~~~~~~~~~~APV AT0 0 10 20 so 100 Feet -a Scale LF1 L1 ------ CRIPPEN CONSULTANTS, IC U - ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~SEAT TLE I ~~~~Minimum pool elevation 3 ~~~~~~~~~~~~~~~~~~~-otl 2- -A h- Shee't piling SECTION THROUGH OUTLET WORKS o-1Oa.~~~.A~wo Feet -Damn Gaet clot '1~f. -0".Rlprap on filter cloth \Second saeconcreteLW . DETAIL I DETAIL 2 . SECTION A-A O~4O26 Feet SECTION THROUGH Scale ~~~~~~~~~~ ~EMERGENCY SPILL WAY II~~~~~~~~~~~~~~~~~Usra hl Die ~~~~~~pool elevation ~~~~7'-0 Steel lner 3 ~~~~~~~~~SECTION THROUGH SERVICE SPILLWAY Scale r!3-- I D~~~~~a. .~~~~~"e'w ,.. Ge~~~~0- Dm filll~ Stool liner t o ~ ~ w~W~FG 17.2 __ ~~~~~~~~~~~~CITY OF HOMER, ALASKA ~~' *~~~~ FL~~~~J- ~~WATER SOURCE STUDY ~~~~~ ~~~FRITZ CREEK DAM SECTIONS & DETAILS I ____ DETAIL ~~~DETAIL 3 SECTION B-B SECTION C-C D E T A IL_4 PRoj#' 0024 APPV.a l DAT028 Scele LJ-1~~L 25 Feet CRIPPEN CONSULTANTS, INC. ~~~~~~~~~~~~~~~~~~~~SCaI* SEATTLiE C~ ~ ~ ~~~~~~~~~~~~~~~~.A D F0C' ALUMINUM SODA.PLEEOYE6th~ LORI.AT~ ~~~LO S CI,-OERS - 2 .III.)I4IN~~~~~~~~~~~~~~~~ ACALEN . CHEMICAL CHEMIC~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~l. C.EMICA.. 2~~~CE-c~ CEMCA INS~~~~~~~~~~~~~~~~~~~~~~I I ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~BOOSTEK PUMP DAM ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~~ ii ~~~~~~~~~~N'LUENT I> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~3- KAW WATEPR PUMP 40.1 SW 5W A F~~~~~~~~~~~~~~~~~ILTER FIL'TEP. FILTER ItAW VAAvtE PUMP WJ. 1. (.0 F61 PLAWT Alp ,UppL-r FIL rl -T1. IPF/ SW &(o TLJra) (Mr-94TKIPIAA P ~~~C~~~tSIP~~~~~~~t~~~~AL PUMP -I--F .-EPPLUENT I~~~~~~~~~~~~~~~~~~~~~~~~~~r-LUN I GOMPKEGNOS (M~~..kI~.L) SUPFACS WASH PUMP -ursot j--(IA) UFC W)i- PUMP NOLT BACK WASH PUMP NO.1I CUSLP. -AUVR bw TIJR 1,13111IMST911 SURFACE WAGM PUMP NO.a BJICKWA5H PUMP No.?2 I - _______ MA,~~~~~~~~~~~~~~~PSPILR Fm-MTC, 11161M I4. PAOU.AS No.? SW SK.4 ts m 40LI5.IN01P 4(* Iv ~~~~~~~~~~~~~~ I*tI~l* twvre DAMwt H H H1 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ FLOW~~~~~~~~~~~~~DIAGRAM *2O6O~~~~~~~~~~~~~~~~~.l. LODIGAM26 II I OII~~~~~~~~~~~~~~~~~~~~~~I j ~~~~~~~~PROPOSED FRITZ CREEK WATER TREATMENT PLANT l2 I-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~2 34 32 ,� 3~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 28 30 30 ~24 2' I-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~I o 22 �, 280 O *. O ,.~ X 2000 3000 4000 5000 6000 , 5 ~~~~~~RESERVOIR SIZE, Acre-Ft. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~,.''69. ~~~~~I- C 2 4 -"' FIG. 22 ,.1 CITY of HOMER, ALASKA WATER SOURCE STUDY PROJECT COSTS vs. RESERVOIR SIZE 1 ~~~~~~~~~~~~~~PRoj# 0024 APPV. [DATE 3-83 mom ~~CRIPPEN CONSULTANTS, INC. I E.' ~~~~~UI O ,.' X20 18 2000 3000 4000 5000 6000 RESERVOIR SIZE. Acre-Ft. FIG. 22.1 CITY of HOMER, ALASKA WATER SOURCE STUDY PROJECT COSTS vs. RESERVOIR SIZE PROJ* 0024 APPV. DATE 3-83 G3O CRIPPEN CONSULTANTS, INC. E~i 1983 1984 1985 1986 I M|A M J J A S O.N D J F M A M J J A S O N D J F M A M J J A SON D J F M A M J JA S O N D Submittal #4 Submittal #5 Submittal #6 l Submittal #7 fn Geotechnical investigations Financing Negotiations Land. acquisition Design Construction I 1 Reservoir' filling 1 FIGo 23. 1 CITY OF HOMER, ALASKA WATER SOURCE STUDY PROJECT SCHEDULE PROJ# 0024 APPV. :X?( DATE02-83 i]:l]l[R!: O CRIPPEN CONSULTANTS, INC. SEATTLE U I I I GLOSSARY I I I I I I U I I I I U I I GLOSSARY Alluvium. Soil material, such as gravel, sand, silt or clay, that has been deposited on land by streams. Aquifer. A body of rock that contains sufficient saturated permeable material to conduct ground water and to yield economically significant quantities of ground water to wells and springs. Bed. A subdivision of a stratified sequence of rocks, internally composed of relatively homogeneous material exhibiting some degree of lithologic unity. The term is used primarily for a sedimentary unit. Clay. As a soil separate, the mineral soil particles less than 0.002 millimeter in diameter. As a soil textural class, soil material that is 40 percent or more clay, less than 45 percent sand, and less than 40 percent silt. Compaction testing. Refers to a procedure designed by Ralph R. Proctor (1894-1962), U.S. Civil Engineer, to establish water content-density relationships of a remolded soil by application of compactive effort under standardized conditions; gives the "Proctor curve" (or compaction curve) and the ''Proctor density" of soil. Concretion. A hard, compact, normally subspherical mass or aggregate of mineral matter generally formed by orderly and localized precipitation from aqueous solution in the pores of a sedimentary rock and usually of a composition widely different from that of the rock in which it is found. Dip. The angle that a structural surface, e.g. a bedding plane, makes with the horizontal, measured perpendicular to the strike of the structure. (Strike is the direction that a structural surface takes as it intersects the horizontal.) E-Log. A log obtained by using an electronic device in a borehole to detect and record geophysical characteristics of strata. Escarpment. A long, more or less continuous cliff or relatively steep slope facing in one general direction, breaking the general continuity of the land by separating two level or gently sloping surfaces, and produced by erosion or by faulting. Ferruginous. Pertaining to or containing iron, e.g. a sandstone that is cemented with iron oxide. Flood plain. Nearly level land, consisting of stream sediments, that borders a streaom and is subject to flooding unless protected artificially. Glacial drift. Material transported by glacial ice and then deposited; also includes assorted and unassorted materials deposited by streams flowing from glaciers. Glacial till. Unassorted, nonstratified glacial drift consisting of clay, silt, sand, gravel, and boulders transported and deposited by glacial ice. Identification testing. Refers to testing, usually in a laboratory, to determine the classification of soil particularly with respect to gradation of particle sizes. Indurated. Said of a compact rock or soil hardened by the action of pressure, cementation, and especially heat. In-situ testing. Refers to testing of material in place, e.g. testing performed in a drill hole with a "pressure meter" which stresses the walls of the drill hole and measures wall deformations. Kachemak soils. Refers to the Kachemak series which consists of dark-coloured, well-drained, shallow to moderately deep soils that occur on uplands and are nearly level to steep. These soils formed in volcanic ash mixed with silt blown from recently exposed glacial drift. Below the volcanic ash are layers of moderately consolidated shale and sandstone. The elevations range from 800 to 2000 feet. Loam. Soil material that is 7 to 27 percent clay, 28 to 50 percent silt, and less than 52 percent sand. *C B-2 Log. A detailed, systematic, and sequential record of the progress made in drilling a well or b6rehole. It may include notes on the depths and thicknesses of the rocks and earth materials penetrated, geologic structure (dips), and water conditions. Mantle. A general term for an outer covering of material of one kind or another. Muskeg. A bog, usually an acid, very wet, freshwater bog, containing abundant peat moss, frequently with dense tufts of grass or grass-like plants forming deep accumulations of organic material, growing in wet, poorly drained boreal regions. Packer test. Packer testing is used to determine the permeability of a rock mass. A packer consists of a rubber sleeve which can be expanded against the wall of a drill hole. The test consists of pumping water under pressure into a section of a drill hole sealed off with a packer or packers. The quantity of water and the pressure are measured and the "coefficient of permeability" can then be computed. Peat. An unconsolidated deposit of semicarbonized plant remains of a water-saturated environment, such as a bog, and of persistently high moisture content. Permeability. The property or capacity of rock or soil for transmitting water; it is a measure of the relative ease of water flow under unequal pressure. Piping. Erosion by percolating water in a layer of subsoil, resulting in caving and in the formation of narrow conduits, tunnels, or "pipes" through which soluble or granular soil material is removed; especially the movement of material, from the permeable foundation of a dam, by the flow or seepage of water along underground passages. Pressure meter. See in-situ testing. Profile, soil. A vertical section of the soil through all its horizons. Richter scale. The range of numerical values of earthquake magnitude, devised in 1935 by the seismologist C.F. Richter. In theory there is no upper limit to the magnitude of an earthquake. However, the strength of Earth materials produces an actual upper limit of slightly less than 9. B-3 Sand. Individual rock or mineral fragments in soils having diameters ranging from 0.05 to 2.0 mi Ilimeters. Seismic zone. A zone of a "seismic probability map" based on a scale established in the United States, which divided the country into four zones: 0, I, 2 and 3, corresponding to zones of anticipated zero, minor, moderate or major damage from earthquakes. Silt. Individual mineral particles in a soil that range in diameter from the upper limit of clay (0.002 millimeter) to the lower limit of very find sand (0.05 millimeter). Standard blow counts. Said of the "standard penetration test" used to determine the relative densities.of soils. The test determines the number of blows required by a standard weight, when dropped from a standard height (30 in. per blow), to drive a standard sampling'spoon a standard penetration (12 in.). Tertiary age. Said of material deposited in the geologic period thought to have covered the span of time between 65 and three to two million years ago. B-4 I I I V REFERENCES I S I' I V I I I I I I I I REFERENCES 1. USDA, Soil Conservation Service, Engineering and Watershed Planning Unit, Report on Homer-Kachemak Water Supply Investigation, August 1962. 2. Hill, C. A. & Associates, Feasibility Rep6rt for Water Project, City of Homer, December 1971. 3. CH2M-Hill, Inc., Comprehensive Water Plan, Homer, Alaska, May 1977. 4. CH2M-Hill, Inc., Homer Area Water Reservoir Study, Kenai Peninsula Borough, Alaska, October 1980. 5. Hobbs, J., City of Homer, personal communication, Oct. 1982. 6. Pacific Rim Planners & Engineers, Olympic Associates, Homer Comprehensive Plan 1982, Nov. 1982. 7. Feulner, A. J., Water Supply Potential in the Ohlson Mountain Area, Kenai Peninsula, Alaska, Alaska Department of Health and Welfare Hydrological Data No. 22, 1963. 8. Waller, R. M., Feulner, A. J., and Morris, 0. A., Water Resources and Surficial Geology of the Homer Area, South-Central Alaska, USGS, Hydrologic Investigations Atlas HA-187, 1968. 9. Walton, W. C., Groundwater Resource Evaluation, McGraw-Hill, New York, 1970, 664 pp. 10. Fromer, S., Kachemak Engineering Co., personal communication, Sept. 29, 1982. 11. Waller, R. M., Data on Wells in the Homer Area, Alaska Department of Health and Welfare Hydrological Data No. 23, 1963. 12. Farnen, L., City of Homer, personal communication, July 1982. 13. Crenshaw, R., personal communication, Oct. 1982. 14. Koenings, J., Alaska Department of Fish & Game, personal communication, Oct. 1982. 15. DuPont Permasep News, Vol. V, Issue III, DuPont Corp., 1981. 16. Reverse Osmosis Makes Brackish Water Potable, The American City and County, Oct. 1978. 17. Electrodialysis or RO - How do you choose?, World Water, Mar. 1979, p. 37. 18. Quinn, R. M., Operating Experiences on a Reverse Osmosis Plant which Converts Sea Water into Boiler Feed Water, Industrial Water Engineering, Vol. 19, No. 1, Jan/Feb 1982, pp. 20-23. 19. Seawater RO Desalting Moving into Big League, World Water, Mar. 1979, p. 44. 20. Foundation Investigation for City of Homer Dam on Bridge Creek, Hill-Harned & Associates, Apr. 1974. 21. Homer-Ninilchik Area, Alaska, Soil Survey, U.S. Dept. Agriculture, July 1971. 22. Feasibility Report for Water Project, City of Homer, Clair A. Hill & Associates, Anchorage, Alaska, Jan. 1972. 23. Seismicity Study, Homer Hospital, Homer, Alaska, CTA Architects- Engineers-Planners, Alaska Testlab, May 1974. 24. Series of Record Drawings on Bridge Creek Dam including Plan of Borings and Logs of Test Pits, CH2M-Hill, May 1974.