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Attac-'hment #94.4.7 Sanitary Survey for GREAT BAY AND LITTLE BAY NEW HAMPSHIRE New Hampshire Department of Health and Human Services Division of Public Health Services Bureau of Food Protection July 1995 This report was funded in part by a grant from the Office of State Planning, New Hampshire Coastal Program, as authorized by the National Oceanic and Atmospheric Administration (NOAA), Grant Award Number NA470ZO237, HT 424.8 .S26 1995 NH EMU 'Pr;;Z Pubhcation No. 96-001 TABLE OF CONTENTS pg I. Executive Summary 1 U. Description of Growing Area A. Location map showing growing area 32 B. Description of area 1 C. History of growing area 3 III. Pollution Source Survey A. Summary of sources and locations 3 1. Map or chart showing the location of major sources of pollution 34 2. Table of pollution sources 26 B. Identification and evaluation of pollution sources 1. Domestic waste A. Septic systems 7 B. Wastewater treatment plants 8 2. Marinas 12 3. Stormwater 13 4. Agricultuml waste 14 5. Wildlife areas 16 6. Industrial waste 17 IV. Hydrographic and Meteorological Characteristics A. Tides: Type and amplitude 17 B. Rainfall: Amounts, seasonality and frequency of significant rainfalls 18 C. Winds 19 D. River Discharges: Volumes and seasonality 19 E. Actual or potential effects of transport on pollution to the harvest area 20 V. Water Quality Studies A. Map of sampling stations 36 B. Sampling plan justification 21 C. Sample data analysis 21 VI. Interpretation of Data in Detennining Area Classification A. Meteorological and hydrographic effects on bacterial loading 2 B. Variability in the data and causes 2 2 V VII. Conclusions A. Map showing classification 42 B. Legal description 23 C. Management plan 24 D. Recommendations for improvement of sanitary survey 24 VIII. References 25 List of Tables Table 1. Potential pollution sources impacting the growing area with relevant sample sites 26 Table 2. Fecal coliform (#/100ml) counts at low and high tide for JEL stations GB I and GB2, correlated with rainfall up to 24 hrs prior to sampling 27 Table 3. NH DPHS database for sampling sites relevant to the survey area from April 1992 to June 1995. Geometric means, 90th percentile score and classifications of sites are also included. All scores in FC/100ml. 28 Table 4. Fecal coliform concentrations (per 100 ml) at DPHS-established shoreline/ surface water sites 30 Table 5. Fecal coliform concentrations (per 100 ml) at sites in small tributaries surrounding Great Bay 30 Table 6. Effect of a storm event (1.08" on 9/5-9/6) in September 1994, on fecal coliform concentrations (per 100 ml) at sites throughout the classified area. 30 Table 7. Comparison of paired monthly fecal coliforni (#/100ml) concentrations at low (LT) and high tide (HT) for JEL stations GB 1, GB 2, GB 4, and GB 7: 7/93-6/95 31 Table 8. Effect of significant rainfall events on fecal coliform concentrations at sites in the classified area 31 List of Figures Figure 1. Map of the Great Bay Estuary with the survey area outlined in bold 32 Figure 2. Classification of growing area based on the 1991 Sanitary Survey 33 Figure 3. Potential Pollution sources in the growing area 34 Figure 4. DPHS shoreline survey sites (1990) and Jackson Lab (JEL) GB sites 35 Figure 5. Routine sampling sites within the growing area and Jackson Lab tributary sites 36 Figure 6. Sewered areas within the growing area 37 Figure 7. Wastewater treatment plants within the Great Bay Estuary 38 Figure 8. Stormwater drainage streams within the growing area 39 Figure 9A. Ebb current directional flow in Great Bay 40 Figure 9B. Ebb current directional flow in Little Bay 41 Figure 10. A map of the survey area showing classification resulting from 42 the 1995 Sanitary Survey Appendix A Riparian House lots, septic system information and town tax maps 43 Appendix B Copy of letter from K. MacDonald NH DES Subsurface Bureau 59 Appendix C Analysis of contaminated plume transport from the Durham WWT? 60 1. Executive Summary Many improvements have been made in local wastewater treatment facilities, and best management practices at farms and other potential pollution sources have begun to become more prevalent since the previous sanitary survey was published in 1991. The results of the present sanitary survey suggest that new areas can be classified as approved, and the boundaries for other areas are now better defined. The new areas that could become classified as approved are in the northern portion of the growing area, from the present boundary in Little Bay between Adams Point and the cable crossing to a line from the tip of Fox Point to the northern shore of Durham Point, immediately south of the mouth of the Oyster River A thorough analysis of conditions and water quality in the whole growing area support classification of the area with no conditions, including all meteorological and hydrological conditions. ne only exceptions to this are extreme meteorological events such as Hurricane Bob and other rare events that would cause unusual pollution to occur. II. Description of Growing Area A. Location map showing growing area Figure 1 shows the boundaries of the growing area in question which includes the portion of Little Bay, extending south of the mouth of the Oyster River to Furber Strait and the entire Great Bay of southeastern New Hampshire, Boundary lines were drawn approximately 200 meters upstream from the mouths of the Lamprey, Squamscott and Winnicut Rivers. Each of these rivers and the Oyster River, are treated as point sources of pollution for the purpose of this study. The northern boundary line extends east from the southern shore of the mouth of the Oyster River on Durham Point to the western most tip of Fox Point in Newington for the purpose of this Sanitary Survey. B. Description of area The growing area lies within the Great Bay Estuarine System of southeastern New Hampshire. Specifically, the area proceeds southward from the mouth of the Oyster River to include a substantial portion of Little Bay, then further south through Furber Strait at Adams Point to include all of the Great Bay. The northern boundary is drawn eastward from the southern shore of the mouth of the Oyster River to the western most tip of Fox Point, while boundary lines southward exist at the mouths of the Lamprey, Squamscott and Winnicut Rivers. Water movement within the area is governed primarily by tidal currents while secondary influences are provided by the several tributaries that carry freshwater into the area. Beginning at the northern boundary and proceeding counterclockwise around the perimeter of the growing area, major tributaries in the area include the Oyster River, Crommet Creek, the Lamprey River, the Squamscott River and the Winnicut River. The Great Bay and part of Little Bay was designated by the United States Congress and the National Oceanic and Atmospheric Administration (NOAA) as a National Estuarine Research Reserve (NERR) in 1989 to promote long term research and public education in order to better manage and preserve the diversity of natural resources within this vital ecosystem. The Reserve includes 4400 acres of tidal waters and mudflats, with approximately 400 acres of protected lands through conservation easements. Great Bay is a large, shallow embayment with an average depth of 2.7 m, with deeper channels extending to 17.7 m. Little Bay has an average depth of 3.4 m with areas of the central channel extending to 15.2 m. In the southern portion of Great Bay, two channels from the Lamprey and Squamscott Rivers in the southwest and a smaller, less well-defined channel in the southeast meet in the center of the Bay to form a central deep channel which extends northward through Great Bay to Adams Point. This channel carries tidal water into Little Bay. The tidal range of the growing area varies from 2.0 rn at Dover Point, just east of the northern boundary, to 2.1 rn at the mouth of the Squamscott River. The area is subject to strong tidal currents and vertical mixing, limiting the vertical stratification of waters throughout most of the year. During periods of excessive freshwater runoff, partial stratification of the water column can occur. At low tide, approximately 50% of the Great Bay is exposed with most of the intertidal zone consisting of mudflat and macrophyte habitats. The shoreline of Little Bay is also dominated by large tidal mudflats. Extensive salt marshes exist along the upper intertidal zones at the mouths of the Squamscott, Lamprey and Winnicut Rivers and at Crommet Creek. Several bivalve species can be found within the growing area including razor clams (Ensis directus), blue mussels (Mytilus edulis), ribbed mussels (Geukensia demissus) and more importantly, substantial amounts of American oysters, (Crassostrea virginica) and soft shell clams (Mya arenaria). American oyster populations are highest in Great Bay at Nannie Island southwest of Woodman Point. A smaller oyster bed can be found just south of Adams Point. In addition to these two major beds, scattered oysters can be found throughout Great and Little Bay. Together, these beds form a total area of twenty eight acres available for harvest. There are presently no major oyster beds in Little Bay. Soft shell clams are less prevalent, with the abundance in Little Bay estimated to be approximately 4 bushels per acre with a harvestable area of 430 acres. The total harvestable area of soft shell clams within Great Bay is more than double that of Little Bay, with a total of 1000 acres. The shorelines of Little and Great Bay are a mix of residential property, some agricultural land and woodlands. Most of the land surrounding the watershed for the growing area is forested. Agricultural use of shoreline land within the growing area is minimal and sparse. Human population along the growing area is moderate, with concentrated areas along the northwestern shore of Little Bay in Durham, the southeastern shore of Great Bay in Greenland, particularly on Brackett and Weeks Points, and the eastern shore of Little Bay in Newington. These residences on Brackett and Weeks Points are predominantly summer camps which are seasonally occupied . Shoreline ownership around the growing area is typically private, with some lands protected or in government ownership. Acquisition of lands for conservation easements is an ongoing process, with both government and private programs in operation. Two Wildlife Sanctuaries/Habitats which fall under government jurisdiction border the growing area. One is a large protected area 2 which lies on the Newington side of Little Bay, beginning at Welsh Cove and extending southward to Woodman Point, at the site of the former Pease Air Force Base. This natural preserve of 1054 acres, with approximately four miles of shoreline, has been designated as the Great Bay National Wildlife Refuge by the US Fish and Wildlife Service. Similarly, at Adams Point, between Little and Great Bays, there is an established Wildlife Management Area which is administered by the NH Fish and Game Department. C. History of growing area classification The last sanitary survey on this area was conducted by John Seiferth of the NH Division of Public Health Services in March 1991 based on research performed in September of 1990. Classification of this area was based on water quality data from 1988-1991 and 1990 shoreline reconnaissance work. Figure 2 shows that prohibited (a small portion of southwest Great Bay), restricted (Little Bay and some of southwest Great Bay) and approved (north and southeast Great Bay) classifications resulted from this survey. Since these classifications were designated, many efforts have been made throughout the estuary to improve water quality. Most of the wastewater treatment plants (WWTP) within the estuary have upgraded their facilities and received stricter permit requirements from the EPA and the NHDES regarding chlorination and total coliform counts in effluent. Farms within the growing area have begun to adopt Best Management Practices (BMP) in an attempt to reduce fecal contamination to surrounding waters. 111. Pollution Source Survey A. Summary of Sources and Locations 1. Map or chart showing the location of major sources of pollution Figure 3 shows the locations of potential pollution sources to the growing area. A discussion concerning each individual source follows in Section 2. The shoreline survey was conducted by boat at both low and high tide in August and September 1994 by Drs. Richard Langan and Stephen Jones and by foot in highly populated areas during April and May 1995 by Paul Raiche, Andrea Tomlinson and Deborah Lamson. By boat, properties were surveyed at high tide in order to gain close access to shore for better observation, while at low tide, any pipes located below the high water mark could be more readily observed. Homes bordering the growing area were evaluated by looking for malfunctioning septic systems, gray water pipes, outhouses and other potential pollution sources. During shoreline reconnaissance by foot, many land and cellar drains were discovered but none were determined as being potential pollution sources. One old, abandoned outhouse with a cement foundation was found on the northwest side of Great Bay and a suspected malfunctioning septic system was discovered in the same vicinity. Another potentially malfunctioning septic system was found on the east side of Little Bay in Newington. Both systems have been reported to the appropriate town and state officials (See Section IIII A. 2. for results). All major drainage streams (those with a flow of at least 15 gpm) were evaluated and water samples were taken from each of these major streams (see discussion in section In. A. 2.). 3 2. Table of pollution sources Table 1 lists thirteen actual or potential pollution sources found either directly within the growing area or within tributaries which flow into the growing area (Figure 3). Included in Table 1 are "Relevant Sample Sites." These are specific water quality sampling sites that have been designated by both the Division of Public Health Services and the Jackson Estuarine Laboratory staff which will show the effects, if any, that each pollution source listed in Table 1 has on a specific section of the growing area. Figures 4 and 5 show the array of all sampling sites which have been established in order to monitor water quality throughout the growing area. Sites GB I- GB7 (JEL) were established by Jackson Estuarine Laboratory (JEL) based on past and ongoing studies to give a more comprehensive documentation of spacial and temporal water quality trends in the southwest portion of Great Bay (Figure 4). Sites GB4A-GB80 (DPHS) are sites established by DPHS to support the routine classification of the area (Figure 5). Listed below are sampling sites included in Figures 4 and 5 which were routine sample sites in the evaluation of water quality within the growing area for this study. Sample site Location GB 1 (JEL) Off Adams Point, Little Bay GB2 (JEL) Center of northern Great Bay GB3 (JEL) Mid-center Great Bay GB4 (JEL) Southwest Great Bay GB5 (JEL) Mouth of Lamprey River GB6 (JEL) Mouth of Squarnscott River GB7 (JEL) Chapman's Landing, Squamscott Rvr GB4A(DPHS) Same as JEL GB3 GB4B(DPHS) Just east of GB4A GB5(DPHS) Off Woodman Point, Great Bay GB6(DPHS) Northeast Little Bay GB7A(DPHS) Southeast Little Bay GB7B(DPHS) Off Thomas Point, Great Bay GB15(DPHS) Same as JEL GB5 GB16(DPHS) Off Pierce Point, Great Bay GB19(DPHS) Off Fox Point, Little Bay GB23(DPHS) South of Colony Cove, Little Bay GB50(DPHS) Mouth of Oyster River, Little Bay GB80(DPHS) Same as JEL GB6 Data for these sites are presented in Tables 2 and 3 and discussed in Sections IV, V and VI. All major and minor tributaries have been evaluated. The major tributaries, the Lamprey, Squarnscott, Oyster and Winnicut Rivers are being treated as individual point sources of pollution. The results 4 for water samples collected from sites 1S/A-15S (Figure 4), which were established as a result of shoreline survey work performed for the 199l'Sanitation Survey, are shown in Table 4. Fecal coliform concentrations were relatively low (<43/100 ml), except at sites CC, 14S and 15S on July 12, and site 5A on August 9. Sites CC and 5A had lower levels on different dates, and the geometric means for these sites were <43/100 ml. Sites 14S and 15S were sampled once, but these are located well into the mouth of the Squarnscott River, and should be considered as part of this point source to the growing area. Small tributaries that empty into the southeast comer of Great Bay were sampled in the summer of 1994. Figure 5 shows the small tributary sampling sites, G/N I- G/N 11 (excluding G/N 8), and the analytical results are presented in Table 5. Brackett Brook (G/N 1) and the stream north of Great Bay Farm (G/N 7) had little contamination. The other tributaries had higher levels of bacterial contaminants, especially G/N 2 and Foss Brook (G/N 3 & 4), as described below and identified as PS 11 and PS 12, respectively. The other tributaries, Packer Brook (G[N 6), McIntyre Brook (G/N 10), the Winnicut River (G/N 11), and, to a lesser extent, Shaw Brook (G/N 5) and Pickering Brook (G/N 7), all contained elevated levels of fecal coliforms. However, none of these tributaries appear to have much impact on water quality in Great Bay, based on the results for the routine sample sites GB 5 and GB 16 (Table 3; see Section V). Pollution sources listed in Table. 1 and below which are located on the major river tributaries are considered to be either point or non-point sources within these tributaries. A brief explanation of each source and its potential to contaminate the growing area is given below. PS 1, PS 2, PS 3- The Durham, Newmarket and Newfields wastewater treatment plants are potential pollution sources. The Exeter plant was not included as a potential source due to its location at least four miles from the growing area at the mouth of the Squamscott River. Performance standards for these plants have improved over the past five years. Unless an upset occurs at the plants themselves or at a pump station within any of the systems, these plants are considered to be potential, indirect pollution sources. PS 4 - Little Bay Buffalo Farm has potential to contribute fecal contaminants to the growing area in the form of buffalo feces from the gazing fields. This contamination could reach the growing area as direct runoff or through natural drainage streams leading to the growing area from the farm. A sample from site 1A, located just off this farm, had little (6 FC/100 ml) contamination (Table 4). The- grazing fields here are large and the buffalo are scattered throughout the property. Therefore, the likelihood of any centralized contamination is low.This is considered a nonpoint source, having an indirect impact on the growing area PS 5 - Bittersweet Dairy Farm has potential to contaminate the Squamscott River with runoff containing cow feces from the grazing fields. Manure from the bams is stored at least one mile from the river and the grazing fields are well buffered by woodland. This is a nonpoint, indirect 5 source contributing to the water quality of the Squamscott River as a point source of pollution to the overall growing area. PS 6 - Stuart Farm has potential to contaminate the Squamscott River with runoff containing cow feces from hay, corn and grazing fields. The farm has a small solids collection dam, a constructed wetland and a one-way tidal gate in a detention pond as buffers between the farm and the river. The farm is also practicing Best Management Practices, as recommended by the NH Office of State Planning and the Natural Resources Conservation Service. This is a nonpoint, indirect source that may influence the water quality of the Squamscott River as a point source. PS 7- Great Bay Farm is located on the shore of the growing area and has potential to contribute contaminants to southeast Great Bay in the form of runoff containing cow feces from the grazing pastures and runoff from the corn and hay fields. This is considered a nonpoint, indirect source of pollution to the growing area. Samples collected in the summer of 1994 from the Bay (10S, 11 S, 1 1A; Table 4) and the brook on the north border of the farm (G/N 1; Table 5) revealed no significant contart-iination. PS 8 - Beck Horse Farm has little potential for impact on the growing area. The farm has only fifteen horses with a bam setback at least 2000 feet from Great Bay. Potential pollution from the horse farm would come in the form of runoff containing horse feces. A sample from the Bay adjacent to this farm showed no contamination (8S; Table 4). This is a non-point, indirect source of pollution to the growing area. PS 9 - A suspected malfunctioning septic system in Newmarket is a potential pollution source. This system appears to cause leaching of bacterial contaminants into a pond which empties into northwest Great Bay. Fecal coliform tests performed on water samples from the pond outfall on April 17 and May 31. These tests revealed counts of 1250/100ml on April 17 and 15,300/100ml on May 3 1. These counts suggest a septic system malfunction. This situation is in the process of being remedied through contact with the Newmarket Health Inspector and the NH Department of Environmental Services (DES) Subsurface Systems Complaints Division, both of whom have inspected the site. Appendix B contains a follow up letter received from the NH DES. This is a nonpoint, direct source of pollution to the growing area. However, water quality sampling sites in the vicinity of the pond do not validate this source as being a major contributor of fecal contamination to this area. On May 31, a sampling transect was set up beginning at the pond extending northward to Adams Point. Six sites were sampled along this transect and counts of fecal coliforms ranged from <1/100 ml at Adams Point to 27/100 ml 30M from the pond outfall. Other samples taken in the Bay (site 5B) near this site showed no significant contamination (Table 4). These data suggest that fecal contamination from the pond may enter Great Bay, but dilution of contaminants in the tidal water appears to minimize the impact to the growing area. 6 PS 10- The McNeill residence in Durham has four horses. Potential pollution from this site could come from runoff containing horse feces. Manure is collected and stored at least 400 feet from the shoreline. A natural drainage stream runs from the corral area to the growing area. Little contamination was observed at sites in the adjacent bay (site IS; Table 4). This is a nonpoint, indirect pollution source to the growing area. PS 11- Drainage stream G/N 2 located in the southeast comer of Great Bay had -a geometric mean fecal coliform count of 790/100 ml for three sample dates (Table 5). The stream runs adjacent to Great Bay Road in Greenland. The contamination may be caused by septic system-impacted groundwater, runoff or wildlife. This is a nonpoint, direct possible pollution source to the growing area. Routine water scores (site GB16; Table 3) within this region indicate a high attenuation of the stream contaminants before.they enter the growing area. PS 12- Foss Brook (G/N 3 & 4) was also found to have elevated fecal coliforms. Levels at the downstream site (G/N 4) were at least 700/100 ml or higher on the three occasions in which it was sampled (Table 5). Figure 5 shows the location of the sampling site to be at Bayside Road, at least 300 feet from the point at which the stream enters the growing area. By the time the stream empties into the growing area, it is likely that much of the contamination will be diluted on the spot. Water quality scores at GB 16 support this (Table 5). Contaminants may reach Foss Brook from septic system-impacted groundwater, runoff or wildlife. This is a nonpoint, direct source of possible contamination to the growing area. PS 13 - Malfunctioning septic system/gray water pipe in Newington. This septic system was built before NH started approving septic systems through the NH DES. The owner informed the shoreline survey team that the two visible 3" PVC pipes were connected to the septic tank and one to the leach field of the septic system. The same property also has a gray water pipe which discharges laundry water only onto the lawn and eventually some of can reaches the bay. Upon returning to this site to obtain a sample of each of these discharge pipes, no flow from any of the pipes could be detected. Samples of bay water adjacent to this site revealed no significant contamination (sites 13S, 13A; Table 4). This system remains under investigation. B. Identification and evaluation of pollution sources 1. Domestic wastes A. Septic systems Towns abutting the growing area 'With residences on septic systems are Durham, Newmarket, Newfields, Stratham, Greenland and Newington. The most densely populated areas are Brackett and Weeks Points in Greenland and Durham Point in Durham. Seasonal cottages make up the bulk of the homes on the points in Greenland, while homes on Durham Point are 7 year-round residences. Moderately populated areas are on the east shore of Little Bay in Newington and the west shore of Great Bay in Durham and Newmarket. Research was carried out at each town hall in order to obtain septic system information for each residence within 500 feet from shore (see Appendix A). When available, detailed information including soil type, leach field area and distance from shore for each individual septic system was obtained. Where this information was not available, the year the residence was built is given. Locations of homes are given by map and lot number for each town according to the town tax maps (also Appendix A). All homes within the growing area have individual septic systems with the exception of a few homes on Moody Point in Newmarket which are linked to the town's municipal sewer system (Figure 6). Soil suitability for septic tanks along the growing area shores varies. Land closest to shore is predominantly composed of marine clays and shale. Moving inland from shore, gravel and sand deposits over a base of metasedimentary hard rock predominate. B. Wastewater treatment plants There are several municipal wastewater treatment plants which discharge into the waters of the Great Bay Estuarine system, none of which discharge directly into the growing area (Figure 7). Those which may indirectly impact the growing area due to their location on tributaries associated with Great and Little Bays are described with a summary of operations as follows. Durham WWT P: The Durham Wastewater Treatment Plant is located off Route 4, along the northern shore of the Oyster River in Durham. The plant is approximately two miles upstream from the mouth of the river where it meets Little Bay. The plant went on line in 1935 as a primary treatment facility and was upgraded to secondary treatment in 1981. The plant services 850 residences from the town of Durham and the entire University of New Hampshire (UNH). Serviced areas are all located west of the tidal dam in downtown Durham, north of the tidal portion of the Oyster River and west of the WWTP. Thus, all areas along the southern shore of the tidal portion of the Oyster River are serviced by septic systems, in addition to areas on the northern shore east of the WWTP (Figure 6). No industrial waste is processed through the plant. Wastewater is treated by grit removal, primary and secondary clarifiers, aeration tanks and then chlorination before discharge. All systems are duplicated. Dechlorination facilities are presently being installed with a projected completion date of late spring of 1995. Design flow at Durham is 2.5 MGD, average flow for 1994 was .98 MGD while peak flow reached 4.5 MGD in March 1994. Like all wastewater treatment facilities, Durham has some infiltration problems in wet weather which are continuously being abated. There are no CSO's within the municipal system. The plant is alarmed for high water and power failure with both audio and visual alarms which connect to a dispatcher at UNH. Astaff member is on 24-hour call to respond to the alarms. There is back-up power at the plant to prevent bypassing of wastewater. As a result, there have been no bypassing events in the last five years. There have been four different occasions where there was an overabundance of filamentous bacteria in the secondary clarifier which resulted 8 in solids being discharged into the Oyster River. This occurred as a result of the overactive bacteria causing the solid waste matter to become buoyant, flow over the secondary clarifier weir, through the chlorine contact tank, and into the Oyster River. This particular problem occurred in February 1991, twice in February 1994 and once in February 1995. Ile plant operator has called in outside engineering experts to remedy this problem. Four pump stations transport wastewater to the plant. All are alarmed for high water and power failure and all have back-up power. The main pump station is electronically alarmed and connected to the UNH dispatch. Notification of pump station malfunction follows that of plant malfunction, the person on call is contacted. Effluent is chlorinated at 1-2 ppm just before discharge through two 24" outfall pipes into the nearshore area of the Oyster River where depth ranges from 1-4 feet at mean low tide. Interruptions within the chlorination system are rare. The total coliform. limit for effluent is 70/100ml. The geometric mean for samples analyzed in 1994 was 14/100ml. Studies done on the Oyster River watershed further support the fact that the Durham WWTP had only rare impacts on the contamination levels found in this system (Jones and Langan, 1993, 1994). Compared to the fecal coliform loading produced by tributaries entering the Oyster River, it was found that the Durham outfall contributed only 0.17% of the total fecal coliform contamination within the river. Furthermore, upon sampling all major tributaries which enter Oyster River, it was discovered that the Durham outfall had the lowest fecal coliform counts when compared to scores found at other sites within the watershed, probably due to the disinfecting nature of the residual chlorine in the effluent. Sludge is stored and composted on site in closed containers at least 800 feet from shore. Septage pumped from private septic systems is taken only from Durham. Major upgrades occurred at the Durham plant between 1992 and 1993. They included installation of three new diffusors, replacement of dewatering equipment, aerators and sludge tank covers, wood ash introduced as composting material, new primary and secondary pumps as well as grinders, new effluent flowmeters with ultrasonic sensors and finally, electronic controls at two pump stations. In addition, as mentioned above, dechlorination facilities are in the process of being installed- at this time. As previously mentioned, there have been four documented malfunctions at the Durham plant in the past five years involving buoyant solids overflowing from the secondary clarifier, through the chlorine contact tank and into the Oyster River. Newmarket WWTP: The Newmarket Wastewater Treatment Facility is located off Route 152 along the Lamprey River in Newmarket. The facility is located approximately 1.75 miles from the mouth of the Lamprey River where it, meets the Great Bay. The plant has been serving the community of Newmarket exclusively since construction in 1969, with a current usage of 1200 residences. Wastewater entering the plant is almost entirely domestic, with the exception of 55 GPD of noncontact cooling water waste from a local electronics manufacturer. The plant was upgraded to secondary treatment in 1986. Wastewater is treated by means of primary and secondary clarifiers, trickling filters and chlorination/dechlorination. Design flow is 0.87 MGD, average flow for 1994 was 0.61 MGD while peak flow for 1994 was 2.5 MGD. Infiltration is a 9 problem in wet weather and pipes get constant attention in an attempt to remedy this common problem. There are no CSO's in the system. The plant is alarmed for high water and power failure by means of electronic alarms and back up power is available. Plant p ersonnel are on a rotating, 24 hour on-call basis in order to deal with malfunctions. Wastewater is not able to bypass the plant, however, unchlorinated effluent has been discharged in the past due to a failure in the water supply to the plant. This occurred in October 1993. Five pump stations transport wastewater to the processing area. All are electronically alarmed for high water and power failure. Back-up power is present and provided by the main plant. Problems in the past with the electrical line carrying the back-up power to the pump stations have resulted in some overflowing at the main pump station adjacent to the Lamprey River on Creighton Street. This has occurred three times in the past five years, first in August 1991, then again in April 1992 and sometime in 1993. Another trouble spot during extreme wet weather has been a manhole at Joyce's Kitchen in downtown Newmarket. On days with exceptionally heavy rains, the manhole has burst, sending untreated wastewater into the adjacent Lamprey River. On one occasion in March 1993 during heavy rains, both the manhole at Joyce's and the pump station on Cedar Street overflowed. Malfunctions with pump stations are handled the same way as those with the plant, where the on- call staff member is contacted by the dispatch. Effluent is treated by means of flow paced chlorination/dechlorination to achieve a final chlorine residual close to 0 ppm. Chlorination contact tanks are duplicated. The outfall pipe is 15" in diameter and discharges into the Lamprey River at a point where the pipe is exposed at mean low tide but completely submerged at high tide. The permit limit for total coliforms in the final effluent is 70/100ml. The geometric mean for total coliforms in 1994 samples was 17/100ml. Sludge is dried and dewatered on site and stored in closed containers until it is taken to the Newmarket landfill. Recent upgrades which have occurred were the installation of a dewatering system and a dechlorination system in 1993. As mentioned above, there have been four documented malfunctions either at the Newmarket plant or at one of the pump stations within the last five years. Newfields WWTP: The Newfields Wastewater Treatment Facility is located off Route 85 on the Squarnscott River in Newfields. The plant is approximately 2.5 miles from the mouth of the river where it enters into the southwest portion of Great Bay. The facility has been on line since 1983 serving the community of Newfields only, with a present day total of 157 residences and three minor industries hooked into the system. Pretreated industrial waste comes from Kingston-Warren, a manufacturing company specializing in window moldings and metal shelving. The two remaining industries are screenprinting companies which have just moved to the Newfields area. Due to the recent relocation of these two screenprinting companies to Newfields, their industrial operations are still being reviewed by the town of Newfields and pretreatment requirements of screenprinting waste are pending. The Newfields facility treats wastewater by means of a three-part lagoon system which acts as secondary treatment. Influent is first treated with grit removal, then aerated in lagoons and finally chlorinated and discharged. Occasionally, there will be days when discharge does not occur and wastewater is simply stored in the lagoons. Design flow for the plant is 0. 117 MGD, average flow for 1994 was 0.042 MGD while peak flow 10 was 0.243 MGD in 1994. There are no CSO's within the system and minor infiltration problems in wet weather. The plant is alarmed for power failure by means of an electronic telephone connected to a dispatcher. Back-up power is available. Due to the size of the three-part lagoon system, an alarm for high water is considered unnecessary and there is no possibility for wastewater to bypass the plant. If a malfunction should occur, the on-call employee would be immediately notified by the dispatcher. Two pump stations carry wastewater to the lagoons. Both are alarmed for high water and power failure and both have back-up power. Pump stations are equipped with both dry and wet wells, and bypassing throughout the system would occur via a manhole before a pump station. Malfunctions at pump stations are handled in the same manner as those with the plant. The -effluent is chlorinated at a concentration of @!2ppm just after the third lagoon. Chlorination contact tanks are duplicated. Required installation of dechlorination facilities is currently pending on the permit from NH DES which is up for renewal this year. The total coliform limit for effluent is the standard 70/100ml. The geometric mean for TC in 1994 samples was <24/100mL The outfall pipe is located in the Squamscott River where mean low tide depth is 3 feet. Discharge occurs on the outgoing tide twice per day. There is no ongoing treatment of sludge for lagoon systems, which is stored on the bottom of the lagoons and pumped every 15-20 years. There have been no recent renovations to the system and no documented upsets within the past five years. Exeter V;NWP: The Exeter Wastewater Treatment Facility is located on Newfields Road along the upper Squamscott River, just south of the Route 101 bridge in Exeter. This plant has a low potential for impact on the growing area due to its location at least 4 miles upstream from the mouth of the river. The lagoon-style system was constructed and on-line in 1990. Prior to this, the system was a series of stabilization ponds providing primary treatment and was upgraded in 199 0 to provide adequate treatment of wastewater entering the system. Exeter residents, GTE of Exeter and the Exeter Hospital are all served by the plant. A total of 3300 domestic units are connected to the system. Like Newfields, the Exeter facility utilizes three aerated lagoon systems with chlorination/dechl orination to achieve secondary treatment. Design flow for the plant is 3.0 MGD, average flow for 1994 was 1.6 MGD while peak flow reached 6.2 MGD. All CSO's were separated from the system in 1992-, except one at the main pump station. Like all sewer lines, there is some minor infiltration with wet weather. The plant is alarmed for power failure with an ele ctronic alarm system which signals a dispatcher. Notification procedures in case of plant malfunction consist of the dispatcher calling the plant operator who is on-call at the time of the malfunction. There are no alarms for high water due to the 75 million gallon holding capacity of the three lagoons. Similarly, wastewater is unable to bypass the plant due to the the holding capacity of the lagoons . Nine pump stations transport was tewater to the lagoons. The main pump station, located on Swazey Parkway in Exeter, contains a CSO, which is activated in heavy rains, draining into the Squamscott River. Pump stations are alarmed for high water and power failure and all are equipped with back-up power. 1 Notification of malfunctions with pump stations are reported in the same manner as those which occur at the plant. Effluent is chlorinated/dechlorinated to achieve a final chlorine residual of close to 0 ppm. The total coliform limit in the effluent is 70/100ml. The geometric, mean for 1994 samples was 13/100 ml, however, there were a total of twenty daily violations in 1994 ranging from 75 to 520 TC/100ml. The problem is thought to originate in the dechlorination system, where there is a possible leak in the lines, contaminating the effluent before it is discharged. This is an ongoing concern for the chief operator and is in the process of being remedied. The outfall pipe is 30" in diameter and is located along the Squamscott River, unsubmerged above the tide line. Sludge is stored on the bottom of the lagoons, which are pumped every 20 years. Bottom feeding catfish are kept in the lagoons to control sludge build up. There have been no major upgrades at the plant since 1990, and there have been no major upsets or documented malfunctions at the plant in the past five years. It should be noted that the term "bypass", as mentioned above in all of the WWTP summaries, is defined as "an intentional diversion of a wastestrearn from a treatment facility ". An example of this would be a gate in a clarifier or a pump station pipe which can be opened in the event of heavy flow to release untreated wastewater. Bypassing is legal in New Hampshire if and only if the event is unavoidable to prevent property damage, personal injury and if there are no other feasible alternatives to prevent untreated wastewater from entering a water body. A bypass differs from an overflow or the discharge of unchlorinated wastewater (PC Stephanie Larson, NH DES). All malfunctions or bypasses which result in untreated wastewater entering a water body must be reported to NH DES within 24 hours of the occurrence. This is a stipulation in all of the above WVVTP permits. 2. Marinas There are no marinas located within the growing area. There are, however, several public boat launches which boaters may use to access the growing area. Those used most frequently are the Newmarket Public Launch on the Lamprey River, the Chapman's Landing Launch on the Squamscott River, the Adams Point Launch on Little Bay and the Durham Public Launch on the Oyster River. Boat traffic within the growing area is minimal from September-May but moderate in the summer months. Due to the shallowness and poor channel markings in the growing area, most leisure boating is done elsewhere within the estuary. There are no known live- aboard boats within the growing area. Several small boats are moored in the south and southeast sections of Great Bay during summer months. In addition, there are twelve moorings in southern Little Bay in the summer. All boats which use moorings are small, the majority of which have no on-board head. The above mentioned mooring sites -are all located in deep water areas with substantial daily flushing. 12 3. Stormwater Stormwater enters the growing area directly through various streams and brooks throughout each bordering town. Figure 8 gives a detailed view of the major drainage streams entering into the growing area. There are no combined sewer overflows (CSO's) in the growing area. Figure 8 shows two drainage streams in Newington labelled 002 and 003. These are permitted NPDES outfalls formerly used by Pease Air Force Base, presently used by the Pease International Tradeport. Ditch 002, or Flagstone Brook flows north from the site and eventually discharges into the northern, downstream portion of Little Bay not included in the growing area. Ditch 003, McIntyre Brook, flows from the runway into Great Bay just south of Fabyan Point. Both brooks are used for disposal of "stormwater runoff from airport activities" according to the NPDES/EPA- issued permit. Activities resulting in the production of this waste include aircraft maintenance, aircraft fueling, painting and stripping, aircraft washing and most significantly, aircraft deicing. McIntyre Brook has the potential for having a more direct impact on the growing area than Flagstone due to the location of the discharge. Major effluent characteristics which require monthly monitoring in McIntyre Brook include pH, oil and grease, primary deicing chemical (propylene glycol), surfactants, trichloroethylene (quarterly), and total recoverable iron and zinc. Most of the runway and aircraft parking apron, industrial shop area and the entire flightline area drain into McIntyre Brook. An oil/water separator is located near the origin of McIntyre Brook and a newly installed separator is-located on Flagstone Brook. One of the main concerns with McIntyre Brook has been the propylene glycol content in the discharged water. This product is used in deicing aircraft and can potentially decrease the amount of dissolved oxygen in water. In 1992, as a part of the Air Force Installation Restoration program, shellfish tissue analysis was performed on samples collected in the vicinity of the Air Force Base. In an effort to evaluate the potential impacts of contaminants released from the Air Force Base into McIntyre Brook, American oysters, softshell clams, ribbed mussels and mummichogs were collected at the mouth of the brook where it discharges into Great Bay. Results of these analyses concluded that aluminum, arsenic and potassium concentrations in shellfish tissue samples exceeded background concentrations . However, the presence of these metals at the concentrations in which they were detected. did not indicate a significant health risk to humans, and the contaminants in McIntyre Brook were not considered by the NH DES as potential health risks (PAFB- Installation and Restoration Program). Other heavy. metals analyses have been performed on shellfish tissue in Great Bay in the past, most recently in 1992. Listed below are results from these tests with detectable concentrations (ppm) listed for arsenic, cadmium, nickel, chromium, lead and mercury. The FDA "edible portion" limits (ppm) are also listed. It is evident from the listed concentrations that there is no risk of heavy metal contamination resulting from the Pease International Tradeport industrial activities. 13 Station Al HZ Thomas Point (1) 5.80* 3.50 2.70 3.10 1.10 0.07 Oyster tissue Nannie Island (1) 8.80 3.70 4.10 3.80 1.30 0.17 Oyster tissue Nannie Island (2) NA* 0.33 0.58 1.20 1.30 NA Mussel tissue FDA Guideline NA 25.0 533.0 87.0 11.5 1.0 Edible portion All concentrations in ppm dry weight NA-not available (1) USEPA/NCCOSC (1994) (2) Isaza et al. (1989) In addition to McIntyre and Flagstone Brooks, there are two non-permitted drainage brooks located on the Pease International Tradeport property which drain into the southeast portion of Great Bay on both sides of McIntyre Brook. They are Peverly Brook and Pickering Brook (Figure 8). Runoff is characterized predominantly by overland flow to these streams. The Pease International Tradeport has adopted a Stormwater Best Management Practices Plan in order to properly handle all stormwater waste originating at the facility. 4. Agricultural waste Agricultural use of land within the growing area has greatly declined during the past fifty years. At present, there are two small horse farms, one dairy farm and one buffalo farm located along the shoreline of the growing area. Other cow farms (both dairy and beef) outside of the growing area are located upstream on the Squamscott River in Stratham (see Figure 3, Pollution Sources). Listed below are brief summaries of activities on these various farms and site numbers which can be cross referenced to Figure 3. Information was obtained through personal communications with farm owner/operators. LangleY71,ittle Bay Buffalo FamVPS4 247 Durham Point Rd. Durham, NH This is a fifty six acre buffalo farm with twenty nine buffalo and one horse located at the northern boundary of the growing area. Animals cannot enter the water and the closest the pasture 14 area gets to the water is about 15 meters. A fence separates the grazing area from the water. Hay is grown on the property with occasional manure spreading. Bittersweet Dairy Farm/PS5 Portsmouth Ave. Stratham, NH This is a three hundred acre farm with 125 cows and two pigs located on the lower Squamscott River outside of the growing area. Animals cannot enter the water and the entire pasture is fenced off. Manure storage is approximately one mile from the Squarnscott River. The pasture is buffered by woodland. Pesticide and fertilizer are used on the fields. Stuart Farm/PS6 John Merrill Portsmouth Ave. Stratham, NH This is a dairy farm with 100-200 cows located on the lower Squamscott River outside of the actual growing area. Cows cannot enter the water directly. Manure storage is located within a picket dam behind the barn. There is a 600 m drainage ditch for the milkhouse wastes and runoff from the manure storage which goes to a pond with a tidal gate, through saltmarsh and then discharged into the Squamscott River. In 1993, the Natural Resources Conservation Service supported construction of a small solids collection dam and a constructed wetland upstream on the ditch close to the manure storage area.* The farm is under Best Management Practices classification as assigned by the NH Office of State Planning. Manure is applied to hay and com fields at rate of 10 tons/acre and 20-25 tons/acre, respectively. There is minimal field application of manure near the drainage ditch. Great Bay Farm/PS7 Cynthia and Allen Smith 125 Newi n*gton Rd. Greenland, NH This is a two hundred thirty nine acre dairy farm with 200 cows, two horses and a pony, located on southeast side of Great Bay. Cows cannot enter the water directly. Manure is stored behind the barn, approximately 1000 meters from the bay. Manure is applied to the hay fields bordering Great Bay at a rate of 10 tons/acre and corn fields from 20-25 tons/acre twice per year. Both fields are buffered by at least 100 feet of woodland. A manure storage system has been installed to cut down on runoff contamination from the barn. The farm is under Bes t Management Practices (BMP) classification as assigned by the NH Office of State Planning. 15 Beck Horse FamVPS8 Franklin Beck 632 Bayside Rd. Greenland, NH This property consists of eighty four acres and fifteen horses used for trail rides, just east of Weeks Point in the southeast portion of Great Bay. Animals have access to the water but do not enter the bay water directly. Manure is stored and spread on hay fields throughout the year. Natural drainage occurs via brooks and streams. Spinney Beef Farm/PS9 241 Fox Point Rd. Newington, NH This is a forty-two acre farm with thirteen beef cows located on Broad Cove, east of the northern boundary of growing area. Manure storage area is approximately 400 meters from a tributary to Picketing Brook. Cows enter this brook on occasion. Manure is spread once a year on the hay fields. McNeill Horses/PS 10 44 Colony Cove Rd. D urham, NH Less than half an acre area with four horses only, located on Durham Point at the northern boundary of the growing area. Horses are primarily kept in the barn and occasionally ridden in a fenced in area about 15 meters from shore. The horses cannot enter the water. Manure is collected and transported daily to a storage area 130 meters from shoreline. Some natural drainage occurs from the riding area into Little Bay. No fertilizers or pesticides are used on the land. All of the above mentioned farms are practicing responsible management procedures to prevent manure'from contaminating the respective bordering water bodies. Nonetheless, runoff from these farms, especially in spring time, may contribute to nonpoint source pollution within the growing area or to tributaries entering the growing area. 5. Wildlife areas There are two wildlife preserves within the growing area. One is located in Newington at the site of the former Pease Air Force Base. It consists of a 1054 acre area bordering Little and Great Bay which has been designated as a Wildlife Sanctuary by the National Fish and Wildlife Service. The other preserve is located at Adams Point and adrifinistered by the NH Fish and Game Department as a Wildlife Management Area. Mammals living within the growing area include whitetail deer, beaver, red fox, mink, otter, muskrat, coyote and raccoon. In addition, Great Bay is part of the Atlantic flyway and an important migratory stopover as well as wintering area for many waterfowl and wading birds. As 16 a result, there are substantial populations of both seasonal and year round waterfowl throughout the growing area. Common species include cormorants, swans, Canadian geese, bald eagles, sea gulls, terns, ducks, herons, snowy egrets, common loons, and a large variety of perching birds. Waterfowl populations undoubtedly have a direct affect on water quality throughout the growing area. 6. Industrial waste There are no major industrial activities on the shores of Great Bay or Little Bay with the exception of the Pease International Tradeport. Possible impacts of Pease are mentioned in the Stormwater section of this report. Small scale, light manufacturing is practiced along the Lamprey River in Newmarket and along the Squamscott/Exeter River in Exeter and Newfields, well outside of the growing area. IV. Hydrographic and Meteorological Ch aracteristics A. Tides: Type and amplitude Little and Great Bay experience diurnal tides. Mean tidal range varies from 2.0 rn at Dover Point, just east of the northern boundary, to 2.1 m at the mouth of the Squamscott River at the southwest end of the growing area. Water volume within the entire estuary is 166x,06 m3 at low tide, increasing to 230x,06 m3 at high tide. Specifically, the water surface of Great Bay covers 11 km2 at mean low tide, increasing to 23 km2 of water surface area covered at mean high tide. Freshwater input to the growing area comes mainly from the Lamprey, Squamscott, and Winnicut Rivers in the south, and the Oyster Rivet in the north. River flows vary seasonally, the greatest volumes occurring at times of spring runoff. Although freshwater input into the growing area is prevalent, tidal currents regulate overall current direction more than density-driven circulation patterns. Total freshwater input into the estuary represents an average 2% of the tidal prism volume, increasing slightly under wet weather and snowmelt conditions. Tidal current turbulence produces a vertically well mixed water column within the two bays. Distinctive mixing zones resulting from inputs from the east and west sides of Great Bay and the convergence of the Squamscott and Lamprey Rivers that occurs between JEL sites GB2 and GB4, respectively (see Figure 4). Partial stratification may occur during periods of intense freshwater runoff, especially at the upper tidal reaches of the tributaries entering the area. Generally, ebb.currents are faster than flood currents, particularly in areas with restricted cross sectional areas such as Furber Strait. Figure 9 gives a detailed account of mid-ebb circulation patterns in the growing area. Within the growing area, currents tend to flow into the main channel on both ebb and flood tides. At Furber Strait, current speeds average up to 1.0 m/sec: whereas average current speeds range between 0.5- 0.6 m/sec in Great Bay and 0.75 m/sec in Little Bay. The strongest currents within a tidal cycle tend to be concentrated in a central core in the flow, especially in restricted sites such as Furber Strait. In other lower, narrower portions of the growing area, an overall increase in tidal amplitude and energy dissipation can be observed. 17 Flushing time for Great and Little Bay ranges between 18 and 26 days or 36-52 tidal cycles. Contamination to the growing area would be well diluted within this time and dispersed due to the freshwater inputs and strong tidal driven currents into the system. B. Rainfall: Amounts, seasonality and frequency of significant rainfalls Listed below are monthly and yearly total inches of rainfall from January, 1992 to June, 1995. Rain gauge measurements from Durham, NH, were obtained from Dr. Barry Keim and Robert Adams, the present and former NH State Climatologists. The frequency of rainfall events >05748 h are noted in parentheses. 1992 1993 1994 1995 January NA* 1.62(l) 4.88(5) 4.45(4) February NA 2.77(3) 1.60(l) 2.76(3) March NA 4.63(3) 5.46(4) 1.87(l) April NA 4.80(7) 2.76(2) 1.85(l) May NA 0.73(0) 4.02(4) 2.74(3) June NA 2.44(l) 1.73(l) July 4.11(4) 1.49(l) 2.20(l) August 3.58(3) 2.21(3) 4.05(3) September 2.74(4) 4.19(5) 7.26(3) October 3.39(2) 3.08(3) 0.19(0) November 5.20(4) 3.81(4) 2.88(2) December 2.45(3) 5.58(3) 5.55(3) Yearly total 21.47(20) 37.35(34) 42.61(29) 15.59(13) Yearly mean 3.58 (3.3) 3.11 (2.8) 3.55 (2.4) 2.67 (2.2) *NA= Not. Available Overall, the mean monthly rainfall is 3.25", with an average of 2.7 rainfall events/month that were >05748 h. Monthly precipitation ranged from 0. 19 to 7.26 inches, both values for consecutive months (November and October) in 1994. There were a total of 96 1-2 day rainfall events with >0.5" rain within 48 h periods. These events were relatively evenly distributed during the months when shellfish could be harvested (September-June). The sampling conducted for water quality monitoring by DPHS and auxiliary sampling by JEL included 19 of these 96 events. C. Winds Winds affecting the growing area tend to come from the north and northwest in the fall and 18 winter months and from the southwest during spring and summer months. Northeasterly winds are typical of storms. Wind-driven waves can- greatly affect current direction and speed, especially in the shallower areas of Great Bay. Northea st winds tend to restrict ebb currents, holding water in the bays, while southwest winds restrict flood currents from flowing into the growing area. Wind waves that influence the bottom can resuspend sediments, increasing turbidity levels and particle-associated contaminants above those produced by regular tidal currents alone. Wind waves may also influence grain-size distributions and sediment transport within the growing area. Current velocities at the sediment surface can become greater than tidal current velocities as a result of wind waves, especially in the shallower areas of the growing area where overall tidal current strength tends to be low. In general, the effects of tidal currents throughout the bays may at times be significantly modified by wind-driven currents. D. River Discharges: Volumes and seasonality Major tributaries entering into the growing area are the Lamprey, Oyster and Squarnscott Rivers. Listed below are river discharge data in cubic feet per second (cfs) for those three rivers obtained from the US Geological Survey Water Data Reports for water years (October- September) 1992 and 1993. Oyster River 78km2 drainage area Annual mean discharge 16.8 cfs (1992) 18.5 cfs (1993) LamUrev River 543 km2 drainage area Annual mean discharge 258 cfs (1992) 267 cfs (1993) Squamscott R* ver 331 km2 drainage area Annual mean discharge 163 cfs * (1991) *At present, there is no gauge located on the Squarnscott River. The annual mean here is an estimated value based on regression of mean discharge data from Lamprey, Oyster and Salmon Falls Rivers. E. Actual or potential effects of transport on pollution to the harvest area Nonpoint source pollution is the major source of fecal contamination to the classified area, 19 as there are no point sources within the area. Nonpoint source pollution enters the area as either urban runoff, groundwater seepage from on-'site septic systems, wildlife, boats, agricultural runoff, or as the result of shoreline development. Stream flow from tributaries entering the estuary carries 50% of the annual precipitation to the area. This.less saline water is well mixed within the water column and diluted upon entering the respective bays. 'Me impact of one storm event (1.08" rain in 48 h) in September, 1994 on FC concentrations in the classified area is shown in Table 6. FC values remained low (<14 FC/100 ml) over the three day period from GB6 (DPHS) down to GB5 (DPHS). FC levels were slightly higher at GB2 (JEL) the first day, then were <14/100 ml the next two days. At GB 4B, FC levels were high the first day and much lower the next two days. These data suggest that rainfall-associated contaminants can enter the classified area from the tributaries, but are rapidly attenuated in the channels leading into the approved area. Transport of fecal-bome contaminants associated with freshwater in tributaries is dictated to a large extent by tidal mixing. Tidal currents act to disperse contaminants within the growing area by providing a well mixed water column. Since the growing area is subject to daily tidal influence, contaminants are continuously being flushed from the system on outgoing tides. With each incoming tide, a volume almost equal to that present at low tide returns to Great Bay, producing significant dilution of contaminants already present. This water returning to the growing area on an incoming tide will contain some of the same contaminants which were carried out with the ebb tide, but they will be more diluted and dispersed as a result of travel through the estuary. Furthermore, contaminant travel throughout the growing area is confined to the main channels with limited lateral flow and dispersion to shoreline areas. A comparison of more recent (July, 1993 to June, 1995) FC values at four sites (see Figure 4) along a transect from Adams Point into the Squamscott River for paired high and low tide samples is illustrated in Table 7. Geometric mean values for three of the sites (GB2, 4, 7) were significantly higher at low tide than at high tide. This suggests that these sites are significantly affected by the freshwater-associated contaminants most prevalent at low tide. At GB 1, the geometric mean was higher at high tide than at low tide, but the difference was not significant. Other studies at JEL have suggested that the flow of water across the shallows of Great Bay at low tide, especially between GB2 and GB4, has a cleansing effect. This is caused by flocculation and settling of particulate and colloidal materials, with attached bacterial contaminants, when less saline water from the Lamprey and Squamscott rivers mixes with the more saline waters in Great Bay. Thus, tidal currents and mixing have a generally beneficial, cleansing effect on the water overlying the shellfish in the classified area. V. Water Quality Studies A. Map of sampling stations Figure 5 shows the sites established by the NH Division of Public Health Services in order monitor the water quality of the growing area. Several sampling sites have been added to the area since the last survey was performed in 199 1. They are: GB 16, which was added to give a better representation of water quality in the southeast portion of the Great Bay; GB 4B, which together 20 with GB 4A and GB 5 reflect water quality conditions in the central part of Great Bay; GB 7A ant GB 7B, which monitor the southernmost area of Little Bay and the northernmost area of Great Bay respectively; GB 23 and GB 19 which reflect water colunin conditions in northeast and north central Little Bay respectively. These additional sampling sites sampling give a much more comprehensive view of water quality throughout Little and Great Bays. B. Sampling.plan justification Systematic random sampling was used to obtain all water samples. Samples were therefore obtained under both normal and adverse conditions for the past two years. Numerous water quality monitoring programs performed by researchers at Jackson Estuarine Lab have indicated that that fecal coliform concentrations may increase in the tributaries to Great and Little Bays under adverse conditions such as high rainfall and storms, however, no consistent trend has been observed for sampling sites within the growing areas (Tables 2 and 3; also see Section VI). Other water quality studies performed at JEL have shown that there is little difference between fecal coliform counts within the growing area at high and low tide. C. Sample data analysis The database for sampling sites relevant to the survey area are presented in Table 3. Included in the table are the coliform concentrations/100 nil for each station and sampling date, the number of samples collected and the 90th percentile score. The site numbers may be cross referenced with Figure 10 for exact geographic location. The results of the data analysis indicate that sites GB 4A, GB 4B, GB 5, GB 6, GB 7A, GB 7B, GB 16, GB 19 and GB 23 meet the requirements for approved classification using the Systematic Random Sampling Program (i.e. Geometric mean < 14 FC/100 ml and the 90th percentile < 43 FC/100ml). Sites GB 50 and GB 80 satisfy the criteria for restricted waters while GB 15 is prohibited. VI. Interpretation of 'Data in Determining Area Classification A. Meteorological and hydrographic effects on bacterial loading Ile classification of the growing waters depends on the 90th percentile value calculated for water quality data. This value assumes that interniittent pollution events are unknown and random. One potentially identifiable and definable condition that may be a consistent cause of pollution is rainfall-associated runoff. Table 8 shows the number of DPHS or JEL samples associated with either rainfall events of >0.5 of rainfall during a 48 hour time period, or samples where <0.5 inches fell. In addition, the number of samples that had fecal coliform concentrations >43/100 ml are also noted for each rainfall conditio n. Overall, there were 54 DPHS and 68 JEL sample events (122 total) for which data was collected for one or more sites within the classified area. Of these samples, 19 occurred at times where >0.5" rain fell in 48 h, 6 of which had FC >43/100 ml and 13 had FC <43/100 ml. In addition, the 43 FC/100 ml value was violated 7 times following periods 21 where <0.5' rain fell in 48 h, suggesting that pollution events are not consistently associated with rainfall. Referring to Table 3, there were 17 samples that had FC >43/100 ml. Four of these values were recorded on March 30, 1993, when 1.47" of rain had fallen in 48 h on top of deep snow, causing runoff associated with massive snow melt to occur. This phenomenon requires a specific set of conditions and has not occurred every year, oreven frequently, in southeastern NH in the past ten years. Thus, rainfall and other meteorological events do not produce significant unfavorable effects on water quality that are consistent and definable in the classified area. B. Variability in the data and causes Nine of the 13 concentrations >43 FC/100 ml not associated with snowmelt occurred in December 1993 or 1994, when migratory birds are oftenpresent, especially at the northern and southern ends of the classified area. Feces from migratory birds can obviously cause elevated levels of FC in surrounding waters. However, many samples collected during times when birds are present were <14 FC/100 ml, suggesting that the effect of birds is localized to their immediate surroundings and have no consistent impact on the water quality of the growing area (Rivilla and Gonzalez, 1989). Overall, the frequency of samples >43 FC/100 ml is low, and the 90th percentile values'calculated for 9 stations are <43 FC/100 MI. The critical public health concern about intermittent pollution events is that these events may represent periods when "...the shellfish may be exposed to enormous quantities of pollution" (NSSP, 1993). The magnitude of pollution recorded for the growing area from 1992-95 was never very high. For DPHS samples, the highest FC value was 170 at two sites on March 30, 1993, while 12/17 of the samples that were >43 FC/100 ml were <80 FC/100 ml. For JEL samples, the highest FC value was 270/100 ml at GB1 LT in May, 1994, while the other 7 samples that were >43 FC/100 ml were all <75 FC/100 ml. Thus, even with occasional undefined pollution events causing FC values to exceed 43/100 ml, the resulting contamination was still relatively mild and never constituted 'enormous quantities of pollution. It should be noted that FC values in the classified area have been shown to be significantly higher following heavy rainfall events of >4" during 48 h periods. 'Ibis has occurred twice during the last six years as recorded by JEL scientists: once during Hurricane Bob in 1991 when 6.06" fell-in 2 days, and once in September, 1994 after 4.22" of rain fell in 48 h. V11. Conclusions A. Map showing classification The proposed classification of the growing waters in the survey area are shown in Figure 10. Based on the results of this sanitary survey and analysis of the water quality database, it is recommended that the portion of Little Bay, beginning at a line drawn west-northwest from the tip of Fox Point in Newington (43*07'10" north latitude, 70*51'35" west longitude) to the southern shore of the mouth of the Oyster River at Durham Point (43*07'14" north latitude, 70*52'10" west longitude,) southward to the cable crossing be reclassified as approved. An analysis of the potential for impact from the Durham V;V;TP to the reclassified growing area in 22 Little Bay which was based on hydrographic data from a'UNH Masters Thesis (Shanley, 1972) is reported in Appendix C. This analysis concludes that a plume of contaminated wastewater released from the Durham WWTP on the Oyster River could potentially reach the northern portion of the growing area under worst case conditions within 18-24 hours. This would allow the SSCA and the Patrol Agency sufficient time for area closure in the event of a release of untreated sewage from the Durham WWTP. Survey results and water quality database analysis also supports maintenance of an approved classification for the portion of Little Bay south of the cable crossing to Adams Point, in addition to the portion of Great Bay going south from Adams Point along the western shore of the Bay to Randall Point at the Durham-Newmarket line (43*04'50" north latitude, 70*53'27" west longitude), and all the growing waters east of a line drawn south-southeast from Randall Point to Sandy Point on the southern shore of Great Bay in Stratham (43*03'36" north latitude, 70*53'09" west longitude). The mouth of the Winnicut River, defined as the area southeast of a line running from Pierce Point (43*03'12" north latitude, 70*50'44" west longitude) in a west-southwest direction to the Greenland, NH shore (43*03'06" north latitude, 70*51'14" west longitude), should remain unclassified/prohibited. Water quality at the sample site nearest to this line (GB 16) meets the approved classification criteria (Table 3, Figure 5), however, there are no additional sample sites southeast of this line that could support another classification. Water quality studies support a restricted classification for a section of southwest Great Bay, while survey results support a prohibited classification for the far southwestern comer of Great Bay the includes the mouths of the Lamprey and Squamscott Rivers (Fig. 10) B. Legal description The approved classification area is defined as the growing waters bordered by the shoreline beginning at Durham Point on the western shore of Little Bay (43*07'14" north latitude, 70*52'10" west longitude) going southward along the western shore of Little Bay and Great Bay to Randall Point (43*04'50" north latitude, 70*53'27" west longitude), then defined by a line drawn south-southeast from Randall Point to Sandy Point on the southern shore of Great Bay in Stratharn (43*03'36" north latitude, 70*53'09" west longitude), continuing along the southern shore of Great Bay to a line beginning at a point on the Greenland shore (43*03'06" north latitude, 70*51'14" west longitude) and ending at Pierce Point (43*03'12" north latitude, 70*50'44" west longitude), continuing east and north along the eastern shore of Great Bay and Little Bay, ending at Fox Point (43*07'10" north latitude, 70*51'35" west longitude). The restricted area is defined as the area bordered by the western shore of Great Bay beginning at Randalls Point (43*04'50" north latitude, 70*53'27"west longitude) going southward along this shoreline to the northern shore of Lubberland Creek (43*04'28" north latitude, 70*54'02" west longitude), then defined by a line from this point to Stratham Station on the southern shore of Great Bay (43*03'22" north latitude, 70*53'54" west longitude) following the shoreline eastward to Sandy Point (43*03'36" north latitude, 70*53'09" west longitude), then defined by a line going northwest from Sandy Point to Randall Point. 23 C. Management plan: Not Applicable D. Recommendations for improvement of sanitary survey In ensuing years, we recommend that sampling near the borders of the approved.area be expanded to include more sites, especially at the northern boundary. The new sites should be established based on suspected sources of lingering contamination that appears intermittently between the mouths of the Oyster and Bellamy Rivers, and down to the General Sullivan Bridge. Another area of expansion could be up into the Oyster River, where it is wide with expansive mudflats near its mouth. Finally, a more detailed survey could be expanded out of Little Bay and into the Piscataqua River, to join up with other detailed survey areas. It is important to maintain a schedule that allows for frequent sampling at all routine sites. The 90th percentile limit of 43 FC/100 ml can be violated if the database includes a significant proportion of high FC values. In other words, less frequent sampling may run greater risk of a small number of high values forcing classification of approved. areas to be changed to a conditional classification. Conditional classifications require much more intensive management and a great deal of effort accurately define the exact condition under which areas need to be closed. Thus, frequent sampling in areas typically unaffected by pollution events will most likely support the more desired classification of approved. 24 VIII. References Isaza, J., C. Schwalbe and J. Smith. 1989. Preliminary metals and organics survey in shellfish from the Great Bay Estuarine System, New Hampshire, by U.S. Fish and Wildlife Service, New Hampshire Division of Public Health Services, Bureau of Health Risk Assessment, and New Hampshire Department of Fish and Game. Joint Report PHS/FWS/FG 88-1. U.S. Fish and Wildlife Service, Concord, NH. 116 pp. NH Report No. PHS/FWS/FG 89-1. Jones, S.H. and R. Langan. 1993. Oyster River Nonpoint Source Pollution Assessment. Final Report. New Hampshire Coastal Program, New Hampshire Office of State Planning, Concord, NH. Jones, S.H. and R. Langan. 1994. Land Use Impacts on Nonpoint Source Pollution in Coastal New Hampshire Watersheds. Final Report. New Hampshire Coastal Program, New Hampshire Office of State Planning, Concord, NH. National Shellfish Sanitation Program (NSSP). 1993. Manual of Operations Part 1: Sanitation of Growing Areas. 1993 revision. U.S. Food and Drug Administration, Washington, DC. Rivilla, R. and C.C. Gonzalez. 1989. Seasonal variations of pollution in a wildfowl reserve (Donana National Park,'Spain). J. Appl. Bacteriol. 67: 219-223. Shanley, G.E. 1972. The Hydrography of the Oyster River Estuary. Master's Thesis, Department of Earth Sciences, University of New Hampshire. June, 1972. U.S. Environmental Protection Agency and U.S. Naval Command, Control and Ocean Surveillance Center (USEPA/NCCOSC). 1994. Estuarine Ecological Risk Assessment of Portsmouth Naval Shipyard, Kittery, Maine. Technical report 1627. Naval Command, Control and Ocean Surveillance Center, San Diego, CA. 25 M M M M ME" M MM M M M M M M Table 1. Potential Pollution Sources Impacting the Growing Area with Relevant Sample Sites Potential Pollution Sources Within Growing Area Site Source Water body Impact Relevant Sa pie Site PSI Durham WW'17P Oyster River Indirect GB50 PS2 Newmarket WWTP Lamprey River Indirect GB 15 PS3 Newfields WWTP Squamscott River Indirect -GB80,JEL G137 PS4 Little Bay Buffalo Farm Little Bay Indirect GB23,GB6 PS5 Bittersweet Dairy Farm Squamscott River Indirect JEL G137 PS6 Stuart Farm Squarnscott River Indirect JEL G137 PS7 Great Bay Farm Great Bay Indirect GB16, IOS PS8 Beck Horse Farm Great Bay Indirect G/N4, 8S PS9 Suspected malfunctioning septic Great Bay Direct GB7B PSIO McNeil Horses Little Bay Indirect GB23 PSII Drainage stream Great Bay Direct G/N2 PS 12 Foss Brook Great Bay Direct G/N4 PS 13 Malfunctioning septic/gray water pipe Little Bay Direct jGB 6, GB 7A 26 Table 2. Fecal coliform (#1100ml) counts at low and high tide for stations GBI GB2, correlated with rainfall up to twenty four hours prior to sampling Rikinfall (inches) i Day of 24 hr DATE I GBI LT GBI HT GB2 LT GB2 HT !cumulative preiious VI L93 18.0 1 -----70.02 10.00 2A,93 25 1 10.00 10.00 3/4,93 15.0 10.00 10.00 3MM 15.0 10.00 10.00 -3/29,93 2-0 7-1 10.46 10.00 - 4/22o93 1 10.06 10.00 5/6m 7.5 1 10.05 1).00 5/1 L93 1 16.0 17.0 1 10.07 io.00 - 5120M 18.0 1 10.39 10.39 6nA3 4.5 2.0 1 10.83 0.83 6/3N3 5'a 16.0 0.00 0.00 1 6(7M 6.0 9.5 0.47 0.47 6a4M 6.0 15.0 0.00 0.00 6ram 0.8 0.00 0.00 7/5,93 10.00 O.W 7flZ93 4.3 13.8 -ITm 0.00 7/19M 0.3 0.3 0.00 0.00 7/26M 1 0.8 0.3 2.0 1 2.3 0.00 0.00 M7,93 1 0.3 0-3 1 0.61 0.00 WfM 1.0 7-0 0-54 0.11 &W 3.5 0.29 0.00 9/1883 1.0 2-5 -1.06 O.W 8MM 2-9 11.3 0.02 0.00 917/93 2-0 1 5.5 21.5 2.3 0.00 0.00 9/22M 1 4.9 0.02 WOO 10/5)93 1.: 14.8 53 4.9 0.05 10.00 io/12M 5.3 12.0 0.09 0.00 -10/1&93 20 2.5 Trum 10/25M 4.0 12.8 10.00 0.00 IL19M 1.5 7-3 10.00 0.00 12/15M 1 8.9 38.3 10.13 0.09 1113t94 63.0 73.0 0.90 O.W m94 25.5 47.5 0.00 0.00 3/2%94 1.5 5LO 0.28 0.13 4/27194 18.9 32.0 0.60 -0.60 5/11/94 5.5 9.0 14.5 6.0 0.00 0.00 N8,94 9.5 10.5 Tnm o.25 5/25M 25.0 24.0 43.5 13.0 0.52 0.10 5/3 L94 1 270.0 37-0 0.00- fo.00 6AV94 0.9 9.0 TMCC ITmce 6/23M 5 z 0.8 9.9 0.5 O.OD 10.00 W28/94 4.8 0.28 10.00 7/"4 LO 2.0 0.00 - 7/1 L94 0.8 7.5 Tnm IT. 7118/94 0.5 3.5 0.00 10.00 7/2V94 1.3 2.0 2.5 1.8 IT.= 0.00 70,94 0.21 0.21 - O/L94 1.9 20.0 0.00 -0.00 084 1.0 4.0 O.W 0.00 gn$% 1.8 6.0 0.08 -0.08 W3/94 2-5 2.0 73 0.8 035 0.33 9)W% 83 38-5 1.08 0.62 9/7/94 4.5 6.0 0.62 0.62 9AM 4.5 10.5 Tnm Tram 9n"4 3.0 7.5 0.77 0.77 10^94 3.5 3.0 5.8 4.0 O.W 0.00 -101104- 6.0 4.3 7.8 3.5 0.00 0.00- -10/1W% O.W 0.00 IW29% 7.8 8.6 10.00 0.00 11/204 8.5 6.3 0.00 0.00 -12(1%94 5.8 2.0 10.8 8.3 0.41 0.41 1/26P95 61-5 36.0 0.00 0.00 ZPM5 13.0 7.5 0.00 0.00 3/2DO95 9.3 10.3 11.0 7.0 0.00 0.00 411 1M 0.5 29.3 0.5 6.0 0.24 0.24 -5/23,95 1.3 3.5 -0.16 0.16 MOM 3.5 6.0 10.0 5.3 0.50 0.19 0195 2-0 izi 0.00 0600 6/13195 5.8 2.8 16.3 0.19 10.02 67 1 22 49 14 1 3.9 1 7.0 6.9 3@4 5 Scd. dm 1 3.7 1 4.5 30 27 Table3. NH DPHS database for sampling sites relevant to the survey area from April 1992 to June 1995. Geometric means, 90th percentile score and and classifications of sites are also included. All scores in FC/100ml. Rainfall (in hes)__ Day of 24 hr.prior- Date G134A GB4B G135 GB6 GB 7A GB 7B GB 15 GB 16 GB 19 GB 23 GB 50 GB 80 cumulative to sampling_ 4/6/92 4.5 1.8 0.00 0.00 4/13/92 4 2 0.18 -.0.18 4/14/92 1.8 2 2 0.00 0.00 4/20/92 4 1.8 4.5 Trace Trace 5/25/92 4.5 4.5 4.5 4.5 790 13 4.5 Trace Trace 6/22/92 7.81 2 2 1.81 1300 23 23 0.22 7/13/92 1.81 1.8 1.8 2 49 2 7.8 Trace 0.00 9/21/92 1.8 1.8 1.8 1.8 490 1.8 4.5 0.00 0.00 9/28/92 4 7.8 4.5 2 79 6.8 140 0.48 0.48 10/13/92 4.5 7.8 6.8 13 6.8 7.8 330 6.8 46 0.52 0.52 10/19/92 13 2' 1.8 2 1 22 2 14 0.11 0.00 11/9/92 4.51 1.8 7.8 9.31 4 49 17 14 4.5 0.00 0.00 11/16/92 13 9.3 0.00 0.00 3/30/93 170 140 170 130 1100 1.47 0.46 4/27/93 79 13 4 1.8 1300 0.89 0.27 5/25/93 11 7.8 4.5 1.8 280 13 49 0.07 -0.00 6/1/93 2 4.5 2 13 70 2 4 0.83 0.00 6/22/93 7.81 23 11 4.51 230 120 280 0.47 0.08 7/28/93 1.81 1.8 1.8 1.8 170 1.8 17 0.61 0.61 8/24/93 21 1.8 1.8 2 230 1 7 A 13 0.00 0.00 9/7/93 7.81 2 1.8 1.8 14 6.8 2 0.00 0.00 10/5/93 1 11 2 1.8 4 110 2 17 0.05 0.00 10/8/93 1.81 6.8 6.8 - 0.00 --0.00 10/11/93 1.81 2 49 Trace Trace 11/2/93 7.8 11 23 2 49 12 170 0.60 0.6-0 12/20/93 49 34 46 49 23 22 110 0.05 0.0-5 3/31/94 4.5 1.8 0.02 -0.02 4/19/94! 11 i 1.81 2 21 17 1 1 1 8 0.05 -0.0-0 L _5 I 1 0.851 0.60 /17/941 491 701 4.51 21 1101 1 1310-1 28 Table 3. NH DPHS database for sampling sites relevant to the survey area from April 1992 to June 1995. Geometric means, 90th percentile score and and classifications of sites are also included. All scores in FC/100ml. Rainfall (in hes) Day of 24 hr prior Date GB 4A GB 4B G135 GB6 GB 7A GB 7B GB 15 GB 16 GB 19 GB 23 GB 50 GB 80 cumulative to sampling 6/14/94 2 2 1.8 1.8 230 17 23 0.48 0.45 7/26/94 7.8 1.8 2 4.5 230 1 1 49 Trace Trace 8/30/94 2 2 1.8 1.8 1.8 4.5 79 1.8 2 2 11 0.03 0.03 8/30/94 2 2 1.8 1.8 4.5 79 1.8 1.8 2 1 1 0.03 0.03 8/30/94 2 0.03 0.03 10/24/94 13 2 1.8 2 1.8 1.8 79 1.8 2 1.8 4.5- 33 0.00 0.00 10/24/94 6.8 17 0.00 0.00 11/8/94 6.8 4.5 4.5 6.8 4 4.5 49 7.8 13 7.8 6.8 21 0.00 0.00 11/8/94 13 0.00 0.00 12/12/94 33 13 70 49 79 49 1 0.72 0.72 12/19/94 33 27 33 1 1 79 130 0.41 0.41 1/10/95 1 1 14 6.8 2 13 23 0.00 0.00 1/31/95 4.5 2 4.51 4 6.8 23 0.00 0.00 3/21/95 1.8 2 7.8 1 1 14 1 1 13 1.8 0.12 0.00 3/21/95 4.5 0.12 0.00 3/27/95 4.5 2 2 4.5 4.5 7.8 0.00 0.00 4/18/95 1.8 7.8 4.5 7.8 4.5 1.8 1.8 6.8 0.00 0.00 4/18/95 1.8 1.8 0.00 0.00 4/26/95 1.8 1.8 2 1.8 1.8 0.00 0.00 5/2/95 4.5 1.8 6.8 1.8 1.8 2 Trace Trace 5/2/95 1.8 1.8 Trace Trace 5/9/95 1.8 1.8 2 1.8 1.8 0.00 0.00 5/22/95 2 1.8 33 1.8 4.5 0.16 0.00 6/6/95 7.8 2 1.8 4.5 2 1.8 1.8 1.8 1.8 NA NA 6/6/95 1.8 2 2 1.8 2 1.8 17 NA NA Geo Aean 6.571 4.01 3.48, 4.26 3.49 4.73, 90.02 5.24 4.53, 5.68 8.56 20.07, # samples 31.00 33.00 33.00 43.00 19.00 22.00 27.00 17.00 17.00 18-00 32.00 24.00 90th %ile 29.7 17.8 13.6 16.2 10.4 20.1 465.6 21.0 24.5 32.4 79.5 102.6 Classification A A A A I A A P A A A R R 29 Table 4. Fecal colifonn concentrations (per 100 rnL) at DPHS- establislied slioreline/surface water sites. Analyses by JEL. DATE CC IS ]A 2S 3S 3A 4S 5S 5A 5B 6S 6A 7S 7A 8S 8A 9S IOS I IS I IA 12S 13S 13A 14S 15S 7/12/94 66 3 6 7 18 16 5 5 14 0 0 2 75 78 7/13/94 3 20 0 27 0 1 0 5 7/14/94 5 2 7/21/94 2 2 3 8/9/94 14 75 19 9/6/94 15 n= 2 1 1 1 1 1 1 1 2 3 1 2 1 1 1 1 1 1 1 1 2 1 1 1 1 'Geo. Mean 32 3 6 7 18 14 16 5 19 5 2 8 3 20 0 27 0 1 0 5 1 0 2 75 78 Table 5. Fecal coliforin concentrations (per 100 mL) at sites in sm-all tributaries surrounding Great Bay. DATE GNI GN2 GN3 GN4 GN5 GN6 GN7 GN9 GNIO GN11 Brackett Bk Foss Brook Shaw Bk Packer Bk Pickering Bk McIntyre Bk Winnicut R 7/21/94 10 298 2500 50 345 138 1 853 7/27/94 2 360 233 700 23 180 18 10 545 113 9/6/94 18 4600 4700 160 355 64 172 165 250 n= 3 3 1 2 3 3 3 3 3 2 lGeo. Mean 7 790 233 2019 56 280 54 12 425 168 Table 6. Effect of a stonn event (1.08" on 9/5-9/6) in September, 1994, on fecal coliform concentrations (per 100 mL) at sites throughout die classified area. Station 9/6/94 qn194 9/8/94 Geo. Mean (site) GB6 10 4.0 3.0 4.9 GB50 40 16 7.0 16.5 GB7B (GB 1) 8.3 4.5 3.0 4.8 GB5 6.0 2.8 0.5 2.0 (Gl32) 39 11 7.5 14 GB4B (GB3) 101 23 23 38 GB4 57 38 40 44 GB15 765 150 60 190 GB80 (GB6) 75 69 65 69 (GB7) 110 260 157 165 ,Geo. Mean (date)l 44 21 13 1 30 Table 7. Comparison of paired monthly fecal coliform (#/100ml) concentrations (per 100 ml) at low (LT) and high (HT) tide for TEL stations GB 1, GB2, GB4, and GB7: 7/93-6/95. DATE GB1 LT GBI HT GB2 LT GB2 HT GB4 LT GB4 HT GB7 LT GB7 HT 7/26/93 0.8 0.3 2.0 2.3 40 1.5 135 2.0 8/3/93 1.0 2.0 9f7/93 2.0 5.5 22 2.3 135 2.0 56 15 10/5/93 1.8 15 5.3 4.8 26 2.3 13 2.3 1/13/94 63 73 109 44 2/21/94 26 48 38 9.0 3/29/94 1.5 51 285 24 4/27/94 19 32 33 42 5/11/94 5.5 8.0 15 6.0 29 3.0 51 3.5 5/25/94 25 24 44 13 104 53 350 140 6/23/94 5.5 0.8 8.8 0.5 38 0.3 18 8.3 7/21/94 1.3 2.0 2.5 1.8 19 0.3 15 7.5 8/23/94 2.5 2.0 7.3 0.8 29 2.0 71 5.5 10/4/94 3.5 3.0 5.8 4.0 25 0.8 62 1.0 10/11/94 6.0 4.3 7.8 3.5 32 3.3 126 8.5 12/19/94 5.8 2.0 11 8.3 16 5.5 48 3.5 1/26/95 62 36 93 83 2/20/95 13 7.5 37 38 3/20/95 8.3 10 11 7.0 11 38 5.5 18 4/11/95 0.5 29 0.5 6.0 16 1.5 36 4.5 5/30/95 3.5 6.0 10 5.3 112 4.5 2.0 44 6/13/95 5.8 2.8 17 50 129 8.0 Geom mean 5.0 7.0 7.4 3.4 34.2 2.5 45.9 11.3 Std. dev. 3.9 4.4 2.9 2.5 2.1- 4.6 3.4 3.7 Paired t test HT> LT LT> HT LT> HT LT> HT results n. s. P < 0.05 P < 0.05 P < 0.05 Table 8. Effect of significant rainfall events on fecal coliform concentrations at sites in the classified area. Source of data #Samples with: DPHS JEL Total Rainfall > 0.5"/48 h 8 11 19 FC > 43/100 ml 4 2 6 FC < 43/100 ml 4 9 13 Rainfall 0-0.5748 h 46 57 103 FC > 43/100 nil 3 4 7 FC < 43/100 ml 43 53 96 31 Salmon Cocheco River Falls R I v e r Bellamy River.-.** Dover 4 3 NEW 1 0 HAMPSHIRE South Durham MAINE Berwick Cyste@' LE v e r S pruce Creek BA Eliot Crommet Creek Adarns Poin( Newmarket Lubberland Newinclon C r e e k'..- 43 V. 05 GREAT SAY L a m p r e y.-. Portsmouth PORTSMOUTH v e r HARBOR 7 Greenland GULF Winnicut Stratham 0 F River MAINE Squamscott R I v e r 7 0 5 0' 7 0 4 0 Figure 1. Map of the Great Bay Estuary with the survey area outlined in bold 32 -V DUAMAU 'NEWINGTON N- M.-P.hj,. DrIk. .1 SI.I. M.-I ---------- G-1@ E A TA( NEWPIEL 3 QAI:ZMLA 0 TRATHAM % ;J Figure 2. Classification of Growing Area Based on the 1991 Sanitary Survey 33 77 z tn, @j Q- Durham Ce > Cem JL UNIVERS:-Y OF i PS 1 \Clerne@nts FW KAM?5HIK&- lan C E HAN u all 2 Sunset, Elor,@ @Q ndj;e '.* - :@j-Hill \rTid4t Crlms@ r - lt=t. /.... .. ", . - r @,@Jlats. r CO er 9a -1rL N r .6 Par. SM 7 % toatI as Imt I ZZ enI @GIgton A@ ARK D' -AJ Alalt cave"'I, 1C, Pik. Bro d.. art I-As E 31 G '@ avel -, Newington 0 1 .1 t.@ m - St4tion o ?as G I, fits* % -1 Ollins' Y "arm.- q Hill- + - A 'P 31, 5s 1Z asa. e@, CIO e. n T?,eaL-, M a //F.,@taq 7- ,.cKe@s K :LIS N a%%, fon @47 _0 7c@ 'G, _N We, 5.7 Q! 'F rber IL It rait -7:A arni t U@�-'-M-T-LITARY `RESEF-`@ATIQN'@' PS 9 ',j.@@,;:Newmarket 1 :1: L P E A 8 E A I R FORCE -BASE -(9 M 401 @Je S. -77 - .@hior@.. A- E Hill P @01 I,, A. 2 "Upper Xa?;:otFs Brown f; g-3 @,a erro f 1-c- Vol&' \5 -7- t,\ _H@G -PORT W@bdrri2l G Harvey," e I :Z Marini -:Lake Pt Faanaway Moddys ----- \ @S A:anor-.. Shackfdrd -4 an She t %7 Twat I Bracketts P Ce i Weeks Pt 48 PS 7 -A, C4"ry ce-'@ _Sw, 1@3 PS 8 _Pi.re P@, Zi raulam Sta- Id A;. FS Kocki -a OZ. r am 7: @-,Ne.fieldtCerri *@r nland' 'C ee k 63 .31 v Stati on, Sharp, N Pq "N-, PS 12 am' 0 sm G --E L 1A D Newfie x@ C, Stra G @-4'ree@iari M 4er@ G,a, Pit 10 eo B3 0 go, Q?n Jewell P S 6 7. h Z 0,Z /,-C undalow li j C.1 G 7- L SLratha S, Winniconi, T R 'A A _:@:- - Cc 95 r-u Stratham Ch E0 1A r Figure 3. Potential Pollution Sources in the Growing ea "o!-, FS 5 -gill ':-Wirinicut MiLil,@' Breakfast :,pond, G-.L.P.n -el oz. 0 U, 34 Hill NI 0 Ir T-T TT." A 19 V Ir r Cur - LA 7: D irham- 4. Ce@ ler > \k Jists C rSITY 6F x NEW HXMPSHIREI -N;4z. S lls"INTERC@ANGE@,' 2 e so- I:t Hills 78 J_@ @ ist te C . \,-., e n r2ms: C G-el Pas ner:4 JYS te r 21, Cor _g 14, "'Baston - .1 .' , ,@ . , - ' Fog& fia rbor r"o G .. .. em % oat I @M@d. 8 M 7 =Fox=- it V. Adlington*_\ Z1. "_M 7 \UT@ AR" 7@_ -',6 1A C16le I T ee a C" P. zi, Br :7 C Nei. 'ineon- - -6 % 1, , _71@y _7 ?qs* ":Z7 S", 52 -iI - d 2S Station L Knight:. 'Y i He S arm 3 Hill: 4 r/ Thtjte, .ckers 3A;- 13A,\ C Neu ngton B k@@- jS '13S C, Cda as E W I.. IN C -0 '-arber L L St 7 , N; U,-! M-11 I TA R Y /R E S E ATIO. N U Z' PEA@E AIR@FORCE -BASE ';7 @-.7hornai n - I Hoyt Hill pper a'.'@ Hill 0 SL 5A 014 E3r6wn r. \GB2 Hil@ Islam's t 76 CS. C Wobdrman,@_ 10 r-t -PORTSM -C \',,@agkey Fa b;a ft GB3 R ;@@ v\ E --- - )" 7 @\_,---@io6clys I. a a n o r... P Paanawav GB 5 @' t Z' ---iShack o-G Pt. -4 -GB 4 Swam z @-'7A 7S c 7 herbu E 6S a 8A 11A S 14S 6A lis eks Pt I ch 48M - M ..8..M CaL-f Ce@J. S ON % .7 tratham Z Pierce Pt e GB6 Sta 10s, 7_@ Rocki 9S 3 @Ne-fieldtcem Greenland' Sharp Z7 N, C Statio C" n:-- 0. -Q P Lao i ML C-3 7,t ni -S aic 0, -E Gj- k N1 LA D 4wo 10. W-wF Greenland-mi G,a,el x Bk .0 Ptt el A evivell Ce@ Camp GundaloW 86. Z.-Z 8 r f . @rke Hill Stratham 0 s' iffinniconic@'. R H A,@@4z: r IT Stratham Ch 0* M' 7': 72h a p P 7.7 a Z,%@innicut/Mii1s 'z j "-"Figure 4. DPHS Shoreline Survey Sites (1990) and Jackson Lab GB s ites z I 35 w Pe. NORTH - HAM P T aN 7@ R, D urna M 7 UNIVERSITY 6F/ > ,F@ HAMPSHIRE- _\ClernL @ t 1@., iC Ce ls@ 'TNTERCHANGE @el2 Sunset, Sorro, Pit Hill r, e V @iid@t Cr- Ken edr Rats ner- C ms: uyS te ry 7 P:t C6 E3, P.,k oat Q GB 50 511 -SM7 Ire,, G F/TARK @q Adlington nI C7 91 C@ r ,r -- -@ -Ni@ - ', GB 19 -6- 7Q Mithes' I r C "P v@fon: I. A 7, GB 23 G13 6 87 % Newineon G,I -Ntation t nigt ins K 11' ;@X N arm;! Hill: At Y J @13- Z4 C. -AZ, 0 0 ewl n B k O,o,- Gaso', liw;i NEV G@ v, 1!9-1 .@- I , , 0 N X-@ u7ber-,- IV,. F S A -A MJ-L I T A R Y -10 N :R E S R) Ne @v m a r ke t @- - - - --i@ " . . EF A T t5 ",BM 401 N@ GB 7B P E A S E AIR @j fFORCE BASE @as Ho Upper Narzr-ojj$:@@ Y, Hill M,@ cc b Bro-n H, zmlk W.cc([email protected] 7:' 7@' CID' PORTSM pe G p- Ha rvey.---@ GB 5 Ma G/N 10 Moo-dys dB 4A GB 4B,- PaianaNvay GB 15. X _,g -Fe a t*l- Fla t rids t G/N 9 Yanor... Z, rac Bketts Pt S r u GB 80!., ..... . . ...... i: Weeks Pt c 6@ M C .1-Y Z B 16 TOr4 Stratham q/N I :--_Pierce FX Sta -Y Rocki@g Baviide. GIN 93 k G/N 7 Ne.hejdt CaM @hiirp , -i -( -Greeril.,nd-@, if If IV, - r 31 COM and8 Stat /N 4 31, G 31N 6 Loa @14 Newfi'efdg- /Qj-' C1 Stra ryi G5--A D 3 G jr -@ " J - *-WS5 Greenland':A G/Nll--- 40 G(an) bo el B@ P't -i17.--1- F(a. tt Th'o 7n @8-og Jewell On C em D 6V Camp Gundalow 7a tkers trathmn Winniconi, R 'A-,T,--H C , .\ - Z A-4 Strathatn Ch*,,@. 00@@ .2 -@A gTo N Figure 5. Routine Sam ling Sites Within the Growing Area and Jackson Lab7- 7, P @Vinnicut/,Nliils to 10* I reakfast,,Nill--'.@ Tributary Sites rtnicut-Mi H Breakfast U :57 36 a L -S OR GREAT BAY EXISTING SEWER SYSTEMS m Treatment Facility U JP H A W @i@ Sewered Area *N. WIMUry Re p 0 x Clf'%A L 0 5 L A A T K A V #3 % IN 14 v p a a ISLES Of SROALS Hame!tl Lfe- Mass. NCW MAIAPSMWC OFTXE Of 37ATE MANNING Figure 6. Sewered Areas Within the Growing Area 37 Rochester WVnT Salmon Cocheco River Falls River Bellamy Dover 4 3 c NEW 100 HAMPSHIRE Dover South MAINE Durham Durham WWTP Berwick Oyste'r* LiTTLE Spruce River creek SAY Eliot Crommet Creek Adams Point Kittery Newmarket gton WNm Kittery WViTP* Newin Lubberland Newington 43 C r e e k 05 Newmarket WWTP GREAT PortsmouthWWTP BAY Portsmouth PORTSMOUTH Lamprey: HARBOR R i v e r Greenland GULF Winnicut OF Stratharn River tewfields WWTF. MAINE Squarnscott 70040' R I v e r 70050' Exeter WWTP Figure 7. Wastewater Treatment Plants Within the Great Bay Estuary 38 L D rhaam'- 7 P! I-,- loll pt@-,71 NI,ERSITY F p _'@'F W M AMPSHTRE i C.A Z. e L; "?a, s'- INTERCHANGE 2 C- 7 n -7 S a So- P.t SU S, H 11 CO C-el P@tS e r - C dOat I C\ 11AUd Z, P_ a -our a", 53 9j.- Irit I @Hen 1 -7 F AILTO. 9i - - %R.1@7 - 1) C A@ -M -.me r .46 A oa-d`7@, C71@' 'F, 87 Ne Newin In C Stati IN '011ins 10' Knight.... 'arm Hill. A, N. - I N B _1L:k T7 as: -t4 Packers pq FaU3 *% 4,.' Newi gt6n -11 71 4 87 Ive G -0. E W \.Ce, N as 3, fu rbe r @Y I Zt it --A T 10 C US RESEf< (.0 5- -NeWmarket PEASE AIR@FORCE BASE IBM 40) 7horn Hoyt Hit HO ,z Hill Q Hill U !:@jk-arr (Bro-n" PP L 'c'_ Hil@ Val$" A.: 'f.sf*.d 0 N Woodrrla@ri Fabys P -inawav a. @:anor: Wo6dys Pt -:::7 c a k f Peat'@_ z swain I' Z_ 'Y Bracketts t P C, Weeks Pt 7 0 c 7. Stratha. S2 ./'Z C.1"ry Ce.@\, -Pierce P ta -Ba@side.. 17 N, Ing N -Greenland"* ., 0 Q Clark 4) Hill. @_4, ce@ iN"fi4IdiC*ffl Stati Sharp .'x 4v 'zi, B 31 G t ttrat arA 0 N .,v f i e@_&@?, 4 *Awl@ Greenlaria' - _f) S B.M .7 f @t,, e r B K. 7 -C PZO, Jewell Z:. Cimp Gundalow C 0 r t Hi A -,M-- :@-@Stratharmn 7@- innicani _"T Bm' Stracharn Chv@ fo 7. Figure 8. Stormwater drainage streams Within the Growing Area B,ea' east r 4 Barton Ow 39 _@Ozb NORTT4 q'A M P T "@-N T1 M/S > -7 > j j A -1 v < GREAT BAY MID-EBB < > VECTOR PLOT Figure 9A. Ebb current directional flow in Great Bay A, 1 M/S A LITTLE BAY MID-EBB A CURRENT VECTOR PLOT V1, Figure 9B. Ebb current directional flow in Little BaY 41 Figure 10. A map of the survey area showing classification resulting from the 1995 Sanitary L-1 4n Survey. Approved Restricted Prohibited/Unclassified AN-1 OUAPIAM AM L `;d 19sa "a @4 NEWFIELa 'kEENLAJYO $7RATHAM 42. M =Aprwix I" = = M = = M = 1=1 PROPERTIES ON THE GREAT BAY MAJIVLOT NAME ADDRE'SS FACILITIEWCOMMENTS INFOAVAILABLE, DURHAM 12/5/02 MacLean 180 Piscatagua Road Septic House built 1969 12/8/02 Town of Durham 156 Pisc@taqua Road Septic House built 1780 12/9/08 Smith 30 Mathes Cove Road Septic See Septic sheet 12/9/09 Durnall 26 Mathes Cove Road Septic House built 1967 12/11/02 Poynter 2 Langley Road Vacant lot 12/1 2_ Langley off Langley Road Vacant lot 12/13/01 Langley 247 Durham Pt. Road Septic House built 1860, Buffalo farm 12/16/10 Casey 12 Willey reek Road Septic House built 1975 12/16/11 Shafmasser 10 Willey Creek Road Vacant lot 12/16/12 Shafmasser 8 Willey Creek Road Septic House built 1976 12/16/13 Andrews 50 Colony Cove Road Septic House built 1976 12/16/14 Penhale 48 Colony Cove Road Septic House built 1974 12/17 McNeill 44 Colony Cove Road Septic House built 1969 12/19 McNeill off Colony Cove Road Vacant lot 12/20 Benning 36 Colony Cove Road Septic House built 1975 12/21 Beckwith 34 Colony Cove Road Septic House built 1950 12/22 Auty 32 Colony Cove Road Septic House built 1961 12/23/01 Thompson 30 Colony ove Road Septic See Septic sheet 12/24/01 Elms/Carlson 26 Colony Cove Road Septic 12/24/02 Nelson 28 Colony Cove Road Septic See Septic sheet 12/24/03 Pierce 24 Colony Cove Road Septic House built 1970 12/25 Lohnes 22 Colony Cove Road Septic House built 1976 12 / 2 7- Cooley 20 Colony Cove Road Septic House built 1925 12 / 2 8_ Langley Langley Isl nd Vacant lot 12/29 Barrett Bickford Island Vacant lot 19/13/6 Beckwith Durham Point Road Vacant lot 19/13/7 McPhee off Dame Road Vacant lot 19/13/8 Beckwith 376 Bay Road Vacant lot 120/1 1 Hoginsk! 1595 Bay Road ISeptic lHouse built 1950 43 PROPERTIES ON THE GREAT BAY 20/2 Hancock 591 Bay Road Septic House built 1960 20/3/1 Bramante 587 Bay Road Septic, uitar shaped pool See Septic sheet 20/3/2 Cheney-England Ltd. 569 Bay Road Septic See Septic sheet 20/3/3 Harriton 583 Bay Road Septic See Septic sheet 20/3/4 Perlman 579 Bay Road Septic, Pool See Septic sheet 20/3/5 Cheney-England Ltd. 575 Bay Road Septic See Septic sheet 20/7/2 Cheney-England Ltd. off Bay Road Vacant lot See Septic sheet 20/7/3 Cheney-England Ud. off Bay Road Vacant lot 20/7/4 State of NH off Bay Road Vacant lot 20/7/5 State of NH off Bay Road Vacant lot 20/7/6 State of NH off Bay Road Vacant lot 20/7/7 State of NH off Bay Road Vacant lot 20/8/1 Cochrane off Bay Road Septic House built 1964 20/8/2 Danahy off Bay Road Septic House built 1968 20/8/3 Randall off Durham Point Road Vacant lot 20/8/4 Ford 433 Bay Road Septic 20/8/7 Cochrane Lot #3 Bay Road Vacant lot 20/9/1 Congdon off Bay Road Septic See Sept c sheet 20/9/2 Loomis 367 Bay Road Septic See Septic sheet 20/10/1 Rous 64 Adams Point Road Vacant lot 20/10/2 Rous 50 Adams Point Road Septic See Sept c sheet 20/11/1 Von Briesen off Bay Road Septic House built 1720 20/11/2 DeCampi 55 Adams Point Road Septic See Sept c sheet 20/12/1 Getchell off Durham Point Road Septic See Septic sheet 20/12/3 Mills off Durham Point 14oad Septic House built 1955 20/12/5 Rollins Stonehouse Farm Septic 20/14/2 Kingman 275 Durham Point Road - Septic House built 1850 20/14/3 Valpey 277 Durham Point Road - Septic See Sept c sheet 20/14/4 Kingman/McDonough 281 Durham Point Road Vacant lot 20/15 Rosebud Real Estate Trus 283 Durham Point Road Septic See Sept c sheet 20/16/1 Chase 273 Durham Point Road Septic See Sept c sheet 20/16/2 Whitaker 271 Durham Point Road Septic, camp Camp built 1960 120/16/3 IChase 1269 Durham Point Road Septic, camp JCamp built 1952 44 PROPERTIES ON THE GREAT BAY Camp built 1958 20/16/4 Webb 265 Durham Point Road Septic, camp 20/16/5 Otis 263 Durham Point Road Septic, camp Camp built 1960 20/16/6 Chase 267 Durham Point Road Septic See Septic sheet 20/18 McIntosh Footman's Island Camp-n facilities NEWMARKET R1/12 Zuk 11 Bayview Drive Vacant lot R1/13 Cohen 13 Bayview Drive Vacant lot R1/14 Cohen 15 Bayview Drive Septic House built 1970 R1/15 Cohen 17 Bayview Drive Vacant lot R11/116 Cohen 19 Bayview Drive Vacant lot R1/17 Zuk 21 Bayview Drive Vacant lot R11/18 Zuk 23 Bayview Drive Vacant lot R-1/16 Pardo 25 Bayview Drive Vacant lot Septic House built 191 0,@ Sep redone R1/20 Fotiades/Moskoff 28 Bayview Drive ti@c r_ __1 979 R1/21 Fotiades/Moskoff 26 Bayview Drive Septic Camp, built 1910, SepUc redone 1979 R1/22 Zuk 20 Bayview Drive Septic House and septic put in 1970's R1/23 Zuk 18 Bayview Drive Vacant lot R1/24 Atherton 14 Bayview Drive Septic House built 1951 R1/28 Pitman 12 Bayview Drive Vacant lot R1/29 Pitman 10 Bayview Drive Vacant lot R11/30 Zuk 8 Bayview Drive Vacant lot R1/34 Pitman 252 Bay Road Septic House built 1951 R 1 /35 Popov 246 Bay Road Vacant lot R1 /36 Popov 230 Bay.R ad Septic See Septic Sheet R1/37 Hatch 210 Bay Road Septic House built 1960 R1/38 Cheney-Smith 200 Bay Road Septic in process See Septic Sheet R1/38/4 Cheney-Smith 15 Barberry Coast Vacant lot R1/38/5 Cheney-Smith 18 Barberry Coast Septic House built 1924 R1/38/6 Cheney-Smith 14 Barberry Coast Septic House built 1920 R1/38/7 Southeast Bank 10 Barberry Coast Vacant lot R1/38/8 Southeast Bank 6 Barberry Coast Vacant lot JRI/39 Pearson Little Bay Road lVacant lot 45 PROPERTIES ON THE GREAT BAY R1/40 Southeast Bank Vols Island Vacantlot R2/36/1 White Lubberland Drive Accessory buildings only R2/36/2 Moody Pt. Co. 2 Lubberland Drive Vacantlot R2/36/3 Moody Pt. Co. 3 Cushing Road Vacantlot R2/36/4 Moody Pt. Co. 511 Cushing Road Town sewer Condos R2/36/5 Moody Pt. Co. 5 Cushing Road Vacant lot R2/36/6 Jay Howland Enter. Cushing Road Vacant lot R2/38 Jaferian 5 Moody Pt. Drive Vacant lot See Septic Sheet R2/40 Great Bay Trust 11 Moody Pt. Drive Vacant lot R2/41 Germain 15 Moody Pt. Drive - Septic House built 1979 R2/41 A Batt 13 Moody Pt. Drive - Septic House built 1978 R2/42 Davidson 17 Moody Pt. Drive - Septic House built 1952 R2/43/1 Weeks 19 Moody Pt. Drive Septic See Septic Sheet R2/4,3/2 Chaves 21 Moody Pt. Drive Septic See Septic Sheet R2/44A Chaves 23 Moody Pt. Drive Vacant lot R3/36 Watson Estate of Wm. 81 New Road Septic House built 1790 R3/41/2 Labonte 117 New Road Vacant lot R3/42 Beaudet 131 New Road Septic See Septic sheet 133/42A Heald 3L New Road Vacant lot R3/43 Champagne off New Road Septic Camp built 1750 R3/44 Hanrahan/Hamel 161 New Road Septic House built 1960 NEWFIELDS 201/4 Boston and Maine RR Railroad trestle No facilities 201/5 Hauschel on Squarnscott River Vacant lot 201/6 Cheney-Smith on Squarnscott River Vacant lot 201/8 LeGault on Squarnscott River Vacant lot 201/9 Long Route 108 Vacant lot 201/10 Williams Route 108 Vacant lot 201/13 Laboute on Squamscott River Vacant lot 201/14 Rogers on Squam cott River Seasonal camp, no facilities 201/15 Edgerley on Squams tt River Septic See Septic sheet 1201/20 lGreat Bay Campground IRoute 108 ISeptic ISee Septic sheet 46 PROPERTiES ON THE GREAT BAY 201/23__Hayden Route 108 Tree/horticultural crops IHouse >800 it 201/26 Chace Route 108 Storage g rage, no facilities STRATHAM ------ 3/37 NH Fish and Game 88 Rt 108 Chapman' Landing, Septic House built 1940,50 ft 3/39 NH Fish and Game Rt 108 Vacant lot Saltmarsh, Chapman's Lnd. 3/40 Turnberry Condo., Inc. 142 Portsmouth Ave Vacant lot Saltmarsh, condo commonland 3/41 Turnberry Condo.,Inc. off Squamscott Road Vacant lot Saltmarsh, condo commonland 3/42 Turnberry Condo.,Inc. off Squamscott Road Vacant lot Saltmarsh, condo commonland 3/43 Turnberry Condo., Inc. off Squamscott Road Vacant lot Saltmarsh, on Squam. House Cr.- 5/1 Batcheider -off Squamscott Road Vacant lot 5/2 Wiggin off Squamscott Road Vacant lot 5/23 Crow off River Road Vacant lot 5/23/01 Harrington off Jason Road Camp, not used Outhouse approx. 150 it 5/24 MacDougall 1 Linda Lane Septic House >1000 ft 5/25 Town of Stratharn off Linda Lane Vacant lot 5/27/03 Brookside Condos off Depot Road Garage fo storage only 5/31 State of NH -off Depot Road Vacant lot Saltmarsh 5/32 Rue 37 Depot Road Vacant lot Saltmarsh 13/23/36 Atlantis Realty Trust Morning Star Drive Vacant lot 13/23/53 Dumbarton Oaks off Dumbarton Oaks Vacant lot Dumbarton Oaks commonland GREENLAND R13/5 NH Fish and Game 89 Depot Road Septic, NERR GB Center See Septic sheet R13/8 Tessier 90 Depot Road Vacantlot R13/9 Scofield off Depot Road Vacantlot R1 3/12 Brackett 43 Great Bay Drive West Vacantlot R1 3/13_ Defillipo 66 Great Bay Drive West Septic R1 3/14A Strong 60 Great Bay Drive West Septic Septic about 15 years old R1 3/17 Schneider 100 Great Bay Drive West Septic, camp R 13/1 8_ Snyder 50 Great Bay Drive West Septic, camp R13/19 ILee 13 Great Bay Drive East ISeptic lHouse built 1992 47 PROPERTIES ON THE GREAT BAY R13/20 Brackett 15 Great Bay Drive East Septic R 13/21 Hession off Great Bay Drive East Septic Rl 3/22 Pinney 21 Great Bay Drive East Septic Septic redone about 1985 R 13/23 Digiovanni 23 Great Bay Drive East Accessory building only R13/24 Digiovanni 25 Great Bay Drive East Septic R 14/1 Brandes 29 Great Bay Drive East Septic R14/2 Thomas 33 Great Bay Drive East Septic R14/2A Dixon 31 Great Bay Drive East Septic Rl 4/3 Johnson 37 Great Bay Drive East Septic R14/3A MacTaggart 35 Great Bay Drive East Septic House and septic about 1972 R14/4 Bliss 41 Great Bay Drive East Septic R14/5 MacTaggart/Johnson 35 Great Bay Drive East Vacant lot R14/6 Portsmouth Savings Bk. 43 Great Bay Drive East Septic R 14/7, _ Myers 45 Great Bay Drive East Septic See Septic sheet R14/8 Carter 51 Great Bay Drive East Septic, camp R14/10 Moreau 30 Bayridge Road Septic, camp R 14 /11 Vickery 24 Bayridge Road Septic, camp R 14/12 Middleton 28 Bayridge Road Septic R14/13 Weeks off Brackett's Pt. Road Farm Rl 4/14 Brackett 22 Brackett's Pt. Road Septic Main house, camp septics 1930-1970's- R 14/18 Weeks 667 Bayside Road Septic Main house, camp septics 1930-1960's R14/30 King 32 Bayridge Road Septic See Sep@flc sheet Rl 4/32 Wohlgethan 22 Bayridg Road R15/2 Beck 632 Bayside Road Septic, p ol Horse farm R15/5 Town of Greenland off Bayside Road Vacant lot Rl 5/10 McCarthy 7 Meloon Road Septic R 15/19 Underwood off Meloon Road Septic Rl 5/20 Town of Greenland off Meloon Road Vacant lot Saltmarsh R 15/21 Town of Greenland off Meloon Road Vacant lot Saltmarsh Rl 5/22 Town of Greenland off Meloon Road Vacant lot Saltmarsh R15/23 Town of Greenland off Meloon Road Vacant lot Saltmarsh Rl 8/1 NH Waterfowl Assoc. Backland Vacant lot Rl 8/3 Town of Greenland Backland Vacant lot 48 PROPERTIES ON THE GREAT BAY R18/9 Wick 4 Bayview Terrace Septic See Se tic sheet Rl 8/10 Wentworth 2 Bayview Terrace Septic See Septic sheet R 18/1 1_ Westley 18 Bayshor Drive Septic See Septic sheet R 18/12 Mayer 13 Fairview Terrace Septic R 18/13 Fay 5 Fairview Terrace Septic See Septic sheet R 18/14 Zwolinski 2 Fairview Terrace Septic See Septic sheet R18/28 Sanderson off Bayshore Drive Vacant lot Saltmarsh R18/29 Sanderson off Bayshore Drive Vacant lot Saltmarsh R18/30 Sanderson off Bayshore Drive Vacant lot Saltmarsh R 18/31 Sanderson off Bayshore Drive Vacant lot Saltmarsh Rl 8/34 Hughes 110 Tide Mill Road Vacant Current use R21/1 5 Ports. Country Club 80 Country Club Ln. Septic R22/1 Smith, Rev.Trust 125 Newington Road Dairy Farm R22/3, Emery 161 Newington Road septics, 2 homes See Septic sheet R22/4 White 201 Newington Road Vacant U10/8 Pickerings Brook Ltd. 27 Pickering Brook Drive Vacant lot U10/9 Pickerings Brook Ltd. 26 Pickering Brook Drive Vacant lot NEWINGTON 1 /1 Town of Newington Fox Point-all Vacant lot 1/2 Butler Goat Island Vacant lot 4/1 Eames 371 Fox Point Road Septic See Septic sheet 4/2 Lembcke 385 Fox Point Road Accessory buildings only 4/3 Blevins 397 Fox Point Road Septic House built 1968 4/4 Vinciarell! off Fox Point Road Septic See Sep@hc sheet 9/2 Ackerley 325 Fox Point Road Septics, 2 residences _ See Septic sheet 9/3 Lamson 71 Little Bay Road Vacant lot 9/4 Lamson 42 Little Bay Road Septic House built 1949, 1 001t 9/4A Lamson 42 Little Bay Road Vacant lot 9/5 Lamson 50 Little Bay Road - Septic. House built 1963, 20 ft 9/6 Mahoney off Little Bay Road - Septic House built 1930, 10011 19/7 Lamson 140 Little Bay Road iSeptic ISee Septic sheet 49 PROPERTIES ON THE GREAT BAY 9/8 Lamson off Little Bay Road Vacantlot 9/9 Lamson off Little Bay Road Vacantlot 15/1 Witham 80 Little Bay Road Septic See Septic sheet 15/2 Bowser 84 Little Bay Road Septic See Septic sheet 15/3 McGee 104 Little Bay Road Septic, Pool Seasonal, b1t. 1966, 100 ft 15/4 Lane 108 Little Bay Road Septic See Septic sheet, Seasonal 15/5 Davis/Perkins 112 Little Bay Road Septic House built 1930 15/6 Trefethen 116 Little Bay Road Septic House built 1970, 100 it 15/7 Russell 148 Little Bay Road Septic House built 1975, 100 ft 1518 Hill 168 Little Bay Road Septic See Se tic sheet 15/10 Cabrera 136 Little Bay Road Vacant lot 15/11 Cabrera 136 Little Bay Road Septic House built 1960 22/3 Smith 30 Gundalow Landing Circle Septic See Septic sheet 22/4 Ross 40 Gundalow Landing Circle Septic See e tic sheet 22/5 Beswick 44 Gundalow Landing Circle Septic See Septic sheet 22/6 Purohit 52 Gundalow Landing Circle - Septic House builtl 985, 100 ft 22/7 Parkinson 4 Brickyard Way Septic See Septic sheet 22/8 Eichler 151 Little Bay Road Vacant lot 22/13 _Myers 188 Little Bay Road - Septic House > 700 ft 23/31 Wolf 34 Welsh Cove Drive Vacant lot 23/32 Hazelton 44 Welsh Vove. Drive - Septic See Septic sheet 23/33 Frink 251 Little Bay Road Vacant lot 29 Pease 35 Pease 40 Pease 41 Pease 45 Pease 46 Pease 47/1 Thomas 509 Newington Road Septic House built 1790 49 Pease 50/1 Beals 162 Fabyan Point Road Septic See Septic sheet 50/2 Drinkwater off Fabyan Point Road Septic, cottage House built 1930 151/1 Field 395 Newington Rocad Vacantlot 50 PROPERTIES ON THE GREAT BAY 51/2 _Upson 425 Newington Road Septic See Septic sheet 51/2A Smith 405 Newington Road Septic See Sep ic sheet 51/3 _Hodgdon off Newingt n Road Septic House built 1840 51/4 Bullock 73 Fabyan Point Road Seoc House built 1970 53/5 Baird 316 Newington Road Septic House built 1945 53/6 Mazeau 315 Newington Road Septic House bIt. 1670, ren. 1958 53/7 Mazeau 315 Newington Road Vacant lot 53/8 Thomas 349 Newington Road Septic -House built 1900 53/9&9A Berounsky off Swan Island Lane Vacant lot 53/11 Connors 381 Newington Road Septic House built 1971 53/12 Welch 385 Newington Road Septic, Pool House built 1974 53/16 Berounsky off Swan Island Lane Septic See Septic sheet 55/1 lWhite 75 Newington Road IVAcantlot I 51 SEPTIC SYSTEM INFORMATION MAP/LOT APPROVAL TYPE PERC TANK FIELD SOIL TYPE W.T. ESHWT I EDGE DISTANCE TO COMMENTS NUMBER DATE BDRM WIN GAL SO FT IN IN IN SURFACE H20 DURIJAM 12/9/08 3/80 4 1500 1520 1 BUXTON 120 24 120 100 FT 12/13101 4/91 1 9 1000 405 HOLLIS-CHARLTON N:) 24 N:) IGO FT 1 BR APT OVER GARAGE 12/13/01 2/93 NA 24 1250 1350 HOLLIS-CHARLTON NA 22 NA > 75 FT 12/16/10 2/74 4 18 1000 880 BZB NA NA NA NA 12/16/12 11/72 4 55 1 GOO 1600 BUXTON 30 NA 27 > 75 FT 12/16/13 8/71 3 40 900 840 1BUXTON NA NA 72 150 FT 12/16/14 10/74 3 50 900 930 BUXTON NA NA NA > 75 FT 12/17 6/71 3 45 1000 900 BUXTON NA NA NA NA 12/23/01 6/70 2-2BR 5 2-100(500 HOLLIS-CHARLTON NA NA NA 135 FT 12/24/02 11/87 3 8 11000 450 BUXTON SILT LOAM NA 135 72 110 FT 20/2 6/09 NA NA 1000 600 NA NA NA NA 130 FT 20/3/1 11/82 4 5 1000 800 FINE SANDY LOAM NA 20 61 > 100 FT 20/3/2 9/91 6 2 NA BUXTON-SCANTIC 23 NA 20 100 FT **2 TANKS-1500,2500 GAL 20/3/3 6/80 4 9 1000 640 HOLLIS CHARLTON NA 20 36 NA 20/3/5 5/80 3 20 -1000 1340 BUXTON 20 11 NA > 75 FT 20/7/2 5/92 4 20 11500 1170 HOLLIS CHARLTON NA 23 30 100 FFT 20/8/4 5/82 2 30 1000 875 BU)(TON 36 36 63 20/8/6 5/91 7 7 2000 1940 -BUXTON NA 18 74 > 125 FT 20/9/1 10/79 4 20 1000 1790 BU)CrON NA 13 NA 140 FT 20/9/2 12/93 4 8 1000 1000 1 HOLLIS-CHARLTON NA NA NA >75 FT 20/10/1 4/83 3 20 1000 1125 HOLLIS-CHARLTON NA 16 16 90 FT 20/10/2 4/83 4 6 1000 901 HOLLIS-CHARLTON NA 29 29 180 FT 20/10/2 5/93 4 20 1500 900 HOLLIS-CHARLTON NA 16 16 180 FT 20/11/2 5/93 4 20 1500 900 HOLLIS-CHARLTON NA 18 18 150 FT 20/12/1 7/82 2 14 1000 650 HOLLIS-CHARLTON NA NA 48 >110 FT 20/14/3 7/85 3 6 1000 480 HOLLIS-CHARLTON NA 41 72 >350 FT 52 SEPTIC SYSTEM INFORMATION 20/15 6/84 4 20 1000 760 HOLLIS-CHARLTON NA 12 48 >75 FT 20/16/1 2/90 3 14 1000 576 HOLLIS-CHARLTON NA 20 40 100 FT NEWMARKET R1/36 12/92 2 8 1000 NA CHATFIELD H&C MO. 5 N.O. R1/38 8/94 4 12 1500 756 40B SHAPLE IGH GL 2 4 36 72 100 FT R2/38 10/94 4 12 1600 720 460B PENNICHUCK 0 20 48 75 FT R2/40 2/923 132 1250 832 BUXTON MO. 12 NO. 125 FT R2/43-1 6/90 3 a 1000 480 CHATFIELD HOLLIS N.O. RO. N.O. >75 FT R2/43-2 8/88 3 14 1000 576 Fill Ro. N.O. N.O. 100 FT R2/44A 6/87 3 14 1000 576 Hh N.O. N.O. N.O. 100 FT R3/42 8/88 3 20 1000 704 CHATFIELD H&C NO. 84 Ro. 128 FT NEWFIELDS I 201/15 12/84 NO SEPTIC INFO 75 FT 201/20 3/86 300 FT Septic for 95 Campsites Approval 102934 GREENLAND R13/5 5/94 open 6 1050 1125 WINDSOR NA NA NA 75 FT Sandy Point Discovery Ctr. R14/7 2/923 60 1500 800 BUXTON/SCANTIC 20 14 No. 75 FT R14/30 10/783 NA INA 975 NA NA NA NA 150 FT R14/32 12/803 28 1000 1500 Gc U0. NA NA 100 FT R18/9 7/884 6 1000 1540 38B 60 28 N.O. 75 FT R 18/10 7/84 3 20 1000 373 Ta 60 172 N.O. R18/11 8/84 12 1000 NA Ea/Ta NA 32 NA 75 FT R18/13 10/833 3 1000 NA Ea/Ta NA 24 NA 75 FT R22/3 11/93 8 2-150(2800 1 460C PENNICHUCK 2 5 30 NA 100 FT R22/3 11/93 8 1500 1000 460C PENNICHUCK 24 31 NA 100 FT 5-2BR 4 NEWINGTON 53 SEPTIC SYSTEM INFORMATION 4/1 10/78 2 2.5 1000 430 WF NA NA NA >100 FT 4/4 12/77 3 2.5 1000 700 w NA 60 NA 100 FT 9/2 7/703 <3 1000 NA Hc 120 NA 120 100 FT 9/2 7/802 3 NA 500 Hc Hinkley NA NA NA 150 FT 9/7 11/91 3 >175 FT App., # 189804 15/1 3 App. # 139885 15/2 3/91 4 100 FT App.# 179328 15/4 3/84 4 100 FT _ App. # 107746, Replaced 15/8 6/71 3 <1 1000 140 Sandy clay U0. NA no. 120 FT 22/3 4/85 5 App. # 120352 22/4 8/854 App. # 124481 22/5 8/854 - App. # 125221 22/7 8/874 App. # 138020 28/32 6/944 2 1600 750 26A Windsor NO. 172 N.O. 150 FT 50/1 3/762 App. # 52678 51/2 10/93 3 51/2A 7/923 App. # 191478 15 /16 10/91 3 App. # 189535 54 G A c K N L A N D 4-12 0 5.11 Idl on 5/0 0/a -J./o 5 5-0 0 1 5-6 Am% 60d 6-1 70 -A_ ...... CIN 0.2 PROPERTY MAP INDEX '-I, E T 9 T11" 11 STRATHAM 4CDCKlrlJG"AkM CC:)Ur4-T-',,'. N.". 191 SE-ILL CO.Pty. OLO TOWF4. MAINg. 55 TOWN OF NEWFlELDS,,,1,-,,-" (Aw. ROCKINGHAM JCT. O@ 201 R Z 202 lol 4rV, Ocir cou 4. 9 HERVYS BAKE COURT S T. HILTON RAILROAD AVE- AVE. *Z* NEWFIELDS Awl 103 4 0 6 FIT tILjt . 2 C 3 20 CP 56 2 /3 FVJI T 4 6 N EVA N STATIOr MAPS U N-41, 10 mIGHT 11 12 N 9 1 3ROLLIN HILL nm IA 1 5 16 18 2 NEWtNGTOf PISCATAOUA 2 22 2- 31---""- 25 26 2 29 30 31 32 33 1AN PEASE IR FORCE 8 SE 35 37 38 9 PORTSMOUTH 4 2 4 4 HOYT HILL 45 47!, 4 " tole /BROWN 'o, HILL 49 51 S21 @5 )T"K T - @12 T 4713, '@N FABYAN POINT 6AfAr #Ar 53 @4 57 NEWINGTON co,-V" 0 0 -14 0 R 22 R-13 R-12 15 R-21 -T. L# R-16 J. u 0 R-11 R -5 u U 3 R-10 U- R-9 R 8 R-5 R-6 R-7 R-4 R-3 R-2 R-1 0 NO" PROPERTY MAP GREENLAND IN[ NEW HAUnHIRE Appendix B State of -New Hampshire DEPARTMENT OF ENVIRONMENTAL SERVICES 6 Hazen Drive. P,0. Box 95, Concord. NH 03302-0095 603-271-3503 FAX 603-271-2867 NHDES TDD.Access: Relay NH 1-800-735-2964 May 19, 1995 Andrea Tomlinson Jackson Estuarine Laboratory 85 Adams Point Road Durham, NH 03824-3427 RE: Pitman Property, Newmarket, NH Dear Ms. Tomlinson: in response to your April 25 letter, a joint site inspection of the Pitman property was conducted on the morning of May 3, 1995, by DES personnel and the Town of Newmarket Health Officer. The property owner, Stanley Pitman, was present. A luxuriant patch of grass was observed leading downslope from what may be a septic system, toward a freshwater pond. While this could be indicative of a failed septic system, no moisture or odor was discerned at time of our inspection. Hence, it could not be concluded at the time that a septic system was in a state of failure (reference: definition of septic system failure in RSA 485-A:Z IV.) inspection of the pond's shoreline revealed tunnels or burrows possibly made by muskrats or other warm-blooded animals. As such animals generate fecal coliform (as do ducks) we feel it is possible for wild life to be the source of the bacteria you encountered. Mr. Pitman commented that his commercial septic system had been "corrected" some time ago. This may been by relocation since some old sewage piping was observed near the pond and if done since July 1, 1967, needed prior state approval. we do not find any approvals under Pitman. We suggest that the area be reinspected from time to time by you, by the Town, and by DES with a view to determine whether or not any septic system is failing. Once failure can be determined, enforcement may be effected jointly by the Town of Newmarket and DES. if you have any questions, please respond to the address shown for the Water Supply and Pollution Control Division. Sincerely, Kenneth J. MacDonald Subsurface Systems Bureau KJM/drt cc: Kenneth Sherwood, HO, Newmarket Dennis Plante, DES AIR RESOURCES DIV. WASTE MANAGEMENT DIV. WATER RESOURCES DIV. WATER SUPPLY & POLLUTION CONTROL DIV, 64 No Main Street 6 Hazen Drive 64 No. Main Street P.O. Box 95 Caller Box 2033 Concord. N.H. 03301 P.O. Box 2008 Concord. N.H. 03302-0095 Concord,NH 03302-2033 Tel. 603-271-2900 Concord NH 03302-2008 Tel. 603-271-3503 Tel 603-271-4370 Fax 603-271-2456 Tel. 603-271-3406 Fax 603-271-2181 Fax 603-271-1381 Fax 603-271-6588 59 Appendix C Analysis of the Potential Impact on the Growing Area of a Contaminated Wastewater Plume Originating at the Durham VVWTP One of the areas identified as needing additional information following review of the Draft Great Bay Sanitary Survey was the potential effect of an upset, or release of non disinfected water from the Durham WWTP on the sanitary quality of Little Bay and Great Bay. To this end, the following documents were reviewed: a 1972 Masters Thesis from UNH entitled The Hydrography of the Oyster River EstngrZ an extensive dataset accumulated over a two year period for nutrient concentrations in the Oyster River; a study conducted in 1994 on transport and dilution of nutrients from the Durham WWTP. Of the documents reviewed, the most helpful was The Hydrography of the Oyster River Estuary. and most of the following analysis is based on the measurements, calculations and modeling conducted for that study. Any particle released in the river at point x as the tide begins to ebb, will travel to a downriver point x1 before the tide reverses and causes the particle to travel in the opposite direction on the flood tide. Since the net seaward transport is the difference between the net inflow (calculated at 6 cm/sec) subtracted from the net outflow (calculated at 8 cm/sec), the particle will travel out of the estuary at a net speed of 2 cm./sec. As determined in the above referenced hydrographic study, total flushing time calculated for the Oyster River is 90 hours under low flow conditions, 80 hours under average flow conditions, and 50 hours under high flow conditions. Flushing time is defined as the the amount of time required for a slug of water originating at the head of the river (i.e. the Mill Pond Dam, a distance of 5 km from the mouth of the river) to be completely transported out of the mouth of the river. This definition takes into account vertical tidal mixing, with significant dilution occurring during each flood tide. If we were to consider a release of untreated sewage at the treatment plant, which is located approximately 3.3 kilometers from the mouth of the river and apply the same flushing rates, it would take 45 hours under average flow conditions before some of this water mass reached the mouth of the Oyster River. In 45 hours, 60 this slug will have been diluted and dispersed by nearly four complete (high- low-high) tidal cycles. To look at it more conservatively, we can assume that there is no vertical mixing, and that the net seaward transport is 8 cm/sec rather than 2 cm/sec. Using this figure, a slug of untreated sewage would begin to reach the mouth of the Oyster River in 11.4 hours, or approximately one complete tidal cycle (high-low-high). Once at the mouth of the river at high slack tide, this water mass would follow ebb currents outward into Little Bay (toward the Sullivan Bridge). Net seaward transport has not been calculated for this section of the bay, however, we can assume that this water mass would make some progress outward before the tide reverses and carries the contaminated slug back toward the Oyster River mouth and, of course of interest to us, the portion of Little Bay included in our recent survey. It would therefore be another full tidal cycle before contaminated water could enter the survey area. By this time, (18-24 hours following the release of the untreated sewage) the slug of water will have been diluted by three flood tides. Based on the tidal prism in the Oyster River, and an average discharge volume of 2.55 x104 m3, the cumulative volume of the river at low tide was calculated to be 1.2 x 106 m3, and the high tide volume of 3.7 x 106 m3. In liters, these volumes translate to 1.2 x 109 and 3.7 x 109 Liters respectively, with a tidal prism of 1.5 x 109 liters. Daily average effluent volume in the Oyster River is = 1.2 MGD of continuous flow. If untreated sewage were released for a four hour period, this would result in a release of .2 million gallons of untreated sewage. If we apply a theoretical concentration of 2 million fecal coliforms per 100 ml of effluent, the total release would amount to a release of 1.48 x 106 Liters with a concentration of 200,000 fecal coliforms per liter. This dilution factor for the first tidal cycle, if we assume mixing with only the amount of water contributed by the tidal prism, would be 1.5 X109/1-48 x 106 = 1.01 x 103 or approximately a factor of 1000, resulting in a plume concentration of 200 fecal coliforms /liter. The plume will have traveled downriver from the plant a distance less than the total distance to the mouth of the river before the tide reverses, pushing the effluent plume back upriver towards the dam. The flooding tide would result in further mixing of the plume with another volume which is at minimum equal to the average tidal prism of 1.5 x109 liters. If we assume that the concentration of the river water at low tide (before the flood tide begins) is 200 fc/liter, and the low tide volume of the river is 1.2x 109, dilution and mixing of this volume would be greater than 2 to 1, (1.5 to 1.2), resulting in a concentration of 95 fc/liter or 950 fc/100ml. At this point in time (slack high tide) the plume 61 is now at the mouth of the Oyster River, continuing to mix with waters of Little Bay as it flows outward toward the General Sullivan Bridge. This area of Little Bay is characterized by turbulent mixing, resulting in a great deal of dilution of the plume as it travels in the ebb tide waters. The potential for portions of this now diluted plume affecting the growing area will depend on: 1) The contaminant concentration of the trailing edge of the plume on the falling tide as it exits the Oyster River 2) The amount of dilution of the plume in Little Bay and the amount of dilution of the plume by the tidal prism of the subsequent flood tide a) _ The portion of the plume that is moved into the portion of Little Bay extending south from the Great Bay Sanitary Survey boundary line (Fox Point to the Southern Shore of the Oyster River) 4) The time between the turn of the tide (18 hours after the upset) and the time it takes for the plume to potentially impact the growing area. The minimum would be 18 hours following the upset, though it is more than likely between 20 and 24 hours. 5) The amount of additional dilution that the plume undergoes as it travels southward into the survey area in Little Bay The answers to these questions may not be necessary at this point. A very conservative outlook was used estimating the time for the plume to reach the mouth of the river (11.5 hrs). The dilution of the plume as it travels through Little Bay (based on a estimate of the low tide volume in the section of Little Bay from the mouth of the Oyster River to Cedar Point is roughly 15 times the high tide volume of the Oyster River. Given the turbulent mixing in this area, the plume would be diluted 15 parts to 1 during the outgoing tide, resulting in a concentration of 63 fc/100 ml in when the tide begins to flood at hour 18. Given this scenario, and if no decay coefficient is applied to the bacteria, it is possible for some contamination (at the 63 fc/100 ml concentration) to reach the survey area 18 to 24 hours following an upset at the Durham WWTP. The concentration of the contaminant plume would therefore realistically be <63 fc/100 ml, and could potentially be less that the water quality standard of 14 fc/100ml. Recommendations for additional work are: 1) Research additional hydrographic information that may potentially be available from either Tom Ballestero at UNH or Mike Marsh at Region I EPA. 2) Request that Dr. Cellikol and Dr. Swift of UNH run a Wasp Model on the Oyster River 3) Run the CORMIX model (version 3.1) for a single port diffuser for the Oyster River 62 If all of these options fail to provide reliable answers, a dye release study could be conducted as part of the NEP project. REFERENCES Shanley, G.E. 1972. The Hydrography of the Oyster River Estuary. Master's Thesis, Department of Earth Sciences, University of New Hampshire. June, 1972. Jones, S. H. and R. Langan. 1994. Land Use Impacts On Nonpoint Source Pollution In Coastal New Hampshire Watersheds. Final Report to the NH Coastal Program, NH Office of State Planning. July 1994. 63 I I I I I I I I I I I I I I I i I -III I I -1 3 6668 14109 3205 5