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Project #94.5.10 STRATEGIES FOR ASSESSING NONPOINT SOURCE POLLUTION IMPACTS ON COASTAL WATERSHEDS A Final Report to The New Hampshire Office of State Planning, New Hampshire Coastal Program Submitted by Dr. Stephen H. Jones and Dr. Richard Langan Jackson Estuarine Laboratory University of New Hampshire July 14, 1995 This Report was funded in part by a grant from the Office of State Planning, New Hampshire Coastal Program, as authorozed by the National Oceanic and Atmospheric Administration (NOAA), Grant Award Number NA470ZO237. TD 224 N4 J66 1995 995 N OFFICE OF @STATEPUWNING HC 0 A S TA L P R OLGmINN STRATEGIES FOR ASSESSING NONPOINT SOURCE POLLUTION IMPACTS ON COASTAL WATERSHEDS A Final Report to The New Hampshire Office of State Planning, New Hampshire Coastal Program Submitted by Dr. Stephen H. Jones and Dr. Richard Langan Jackson Estuarine Laboratory University of New Hampshire July 14, 1995 This Report was funded in part by a grant from the Office of State Planning, New Hampshire Coastal Program, as authorozed by the National Oceanic and Atmospheric Administration (NOAA), Grant Award Number NA470ZO237. oil' 1Pk OFFICE OF @STATTE PUNZNING .4"NE WWI OF La @N HCOASTAL PROGRAM ACKNOWLEDGEMENTS The authors wish to acknowledge the contributions of the following individuals to this project: Mr. Dave Ehnert of the Rockingham Planning Commission for providing GIS maps and RPC reports; Mr. Daniel Marquis and Mr. Ryan Davis on the Jacksoson Estuarine Laboratory (JEL) and the Department of Natural Resources, UNH, for their nonpoint source assessement using GIS; Ms. Deborah Lamson, Ms. Beata Summer-Brason, Ms. Andrea Tomlinson, Mr. Gregory Houle, Mr. Gaston Gingives and Mr. Daniel Boisvert (JEL) for asssisting in field and laboratory work; Ms. Jaimie Wolf for providing analytical services; and again Mr. Daniel Marquis for his report on levels of contaminants in a small tributary to the Squamscott River. INTRODUCTION Ile issue of nonpoint source pollution has become increasingly important in coastal areas. Pollution can directly affect valuable marine and estuarine resources and habitats, and indirectly limit use of economically important species and areas. In New Hampshire, the Great Bay Estuary is the dominant coastal area, and the Squamscott/Exeter River system is a major tributary to the estuary. Two years of study in the Oyster River watershed (Jones and Langan, 1993; 1994a) has provided guidance for designing a one year study for the Squamscotl/Exeter watershed. Nonpoint source pollution in this watershed is of critical importance because of its proximity to the abundant shellfish waters of Great Bay. The Great Bay National Estuarine Research Reserve and the Pease Wildlife Refuge areas also have numerous protected areas that include critical habitats. Numerous studies have focused on or included some scrutiny of pollutants in this watershed. A previous study by Jones (1990) showed that improvements in water quality resulted from the upgrade of the Exeter POTW that year, but also showed lingering problems in the river. Jones and Langan (1994b) assessed the impact of animal waste storage and downstream constructed wetlands at a farm located on the shore of the Squamscott River. An ongoing monitoring program at JEL since 1988 has assessed monthly levels of fecal-borne bacteria, suspended solids and nutrients at Chapmans Landing in the Squarnscott River, and has found levels of contaminants to be decreasing (Langan and Jones, 1995). These data also raised some concerns a few years ago because of apparently increasing levels of suspended solids (TSS). This trend has not been borne out in the past two years. Finally, a two-year study of all of the major tributaries to the estuary included sites in the Exeter/Squamscott River system (Jones and Langan, 1995). The results suggested that the Exeter River probably has little impact on nutrients in the Squamscott River, and other sources are suspected along the tidal Squamscon River, including the two POTWs at Exeter and Newfields. Conversely, bacterial contaminants from the urbanized areas influencing the lower Exeter and upper Squamscott River areas are probably a major source for the system. The effect of storm events on contaminants suggests that urban runoff or other rainfall-related processes (seepage from sewage pipes) from the town of Exeter can especially impact the water quality of the upper and eventually the lower Squamscott River tidal waters. A more-detailed, updated study of the system was needed to address a number of questions. The goals of this study were to: 1) identify pollution sources and problem areas; 2) evaluate known critical factors for designing and assessing processes responsible for contamination of tributaries to the river-, 3) develop and evaluate methods for determining mechanisms that control external loading of suspended solids to the watershed. The focus of the study was on nonpoint sources of pollution, and most of the study areas were non-urban. This approach can serve to focus future efforts on any identified problems associated with residential areas on septic systems, agricultural land practices, excavation, logging, road construction, etc., and at the same time weigh the relative contribution of the largely unevaluated urban areas. 1 METHODS Sample Site Selection and Landuse Data The same strategies used in previous studies to assess nonpoint source pollution in a New Hampshire coastal watershed (Jones and Langan, 1993; 1994) were used in this study. Sampling sites were chosen to allow for assessing contaminant concentrations in the main stem of the tidal river, in each tributary to the river, in the mouths of the tributaries, more detailed sites in major tributaries, and intensive study of one target small tributary. In this study, the Squamscott River sites, designated GB#, were located along a transect from Chapmans Landing to just above the Exeter POTW (Figures I and 2). Ile tributary sites, designated SR#, were located downstream of suspected contaminant sources (housing developments, farms, etc.) and numbered in order going clockwise from Newmarket along the eastern watershed to Exeter and back up the western watershed area. The suspected sources were identified initially by extensive review of available maps and groundtruthing. The tributary mouth sites were designated SR-M#. The intensive tributary site locations were the Exeter River and tributaries, designated ER# and #EXT (Figure 2), and a small stream out of Newmarket through Newfields, designated SRI.# (Figure 1). Sampling was coordinated in some instances to maximize comparisons between different areas and occasionally to follow rain events, which are summarized for all sampling dates in Table 1. Tidal water sampling occurred mostly at low tide. Landuse was assessed by a number of strategies. We first looked at USGS maps to locate housing developments and farms near tributaries. We then used a GIS to identify and quantify landuse areas with high potential for nonpoint source pollution.Spatial analyses were conducted using the Environmental Systems research Institute Inc., ARCANFO software. Ile data layers were obtained from the Rockingham Planning Commission, including the landuse data, hydrography, and the soils data from the NRCS. Sewered areas were excluded, and the soils and landuse coverages were combined. A 75 foot buffer was created around the Squamscott River and its tributaries using the hydrography coverage, which was then overlayed with the combined soils/landuse coverages. The resulting coverage did not include SR25, which falls within the sewered area, and the landuse upstream of SRI. The areas omitted around SRI were in Newmarket, over the border from Newfields. Analy&al Methods Measurements of temperature, salinity, dissolved oxygen, pH and observations of weather conditions were recorded at the sampling times. Separate containers were used for collection of water samples for microbial analyses, suspended solids and nutrient analyses. Sample collection and processing methods were conducted according to JEL SOP's 1.05 and 1.06 (Langan 1992 a & b). Nutrient analyses for JEL samples were done using Lachat Method I 1- 107-06- 1 -C for ammonium, method 30-107-04-1 -A for nitrite/nitrate (Lachat Instruments, 1991) and the wet chemistry method of Strickland and Parsons (1968) for orthophosphate. Microbial analysis of JEL samples involved standard membrane filtration methods using mTEC agar for detection of fecal 2 coliforms, and Escherichia coli, and mE agar for detection of enterococci. RESULTS AND DISCUSSION Updated Database and Assessment of Nonljo*nt Source Pollution in the Watershed Water Qualily Along a Transect of the Squamscott Rive Bacterial and nutrient contaminants were measured at sites in the Squamscott River along a transect from Chapmans Landing (GB7) to just above the Exeter POTW (GB 13) (Table 2). Rainfall can have a negative impact on water quality in the Squamscott River (Jones and Langan, 1995), however, no rainfall occurred within 48 h of sampling on the two sample dates. Levels of contaminants generally increased going upstrearn (Figures 3 and 4). For bacteria, the gradient was most apparent for fecal coliforms and E. coli, which increased from GB7 to GB8, and again from GB8 to GB9, with upstream sites having relatively equal and variable levels (Figure 3). Overall, fecal coliforms increased from 18 to 23 1/100 nil from GB7 to GB 10, and E. coli increased from 14 to 125/100 ml from GB7 to GB 12. Enterococci and C. perfringens showed no obvious and consistent trends. For nutrients, nitrate concentrations were relatively high and exhibited the most obvious gradient, increasing gradually from GB7 to GB 13 over a relatively small range (21 to 37gM). Ammonium concentrations were relatively constant from GB7 to GB 12, then increased at GB 13, while phosphates remained relatively constant throughout. The Squamscott River transect data do not indicate that any tributary, along the stretch of the river sampled, had any obvious influence on water quality. Bacteria and nutrients are subject to biological and physico-chemical processes that could attenuate concentrations with time and space. The river is also influenced by tidal mixing, and dilution with mixing could serve to homogenize contaminants, thus hiding any peak concentrations associated with sources. The diluting effect of tidal water on low tide contamination levels is quite apparent at GB7, as illustrated in Figure 5A. The differences in indicator concentrations between high and low tide are large, with concentrations at high tide quite low. The relationship between fecal colfforms and salinity (conservative indicator of dilution) on 10/25/94 for this transect suggests loading was occurring along the transect between GB 13 and GB7 (Figure 5B). This is apparent from the fecal coliform concentrations that are higher than predicted (above straight line) if fecal coliforms were diluted linearly with salinity. Ile site with the fecal coliform concentration in least agreement with predictions is site GB 10, which is located near the mouth of the SR9 tributary. 'Me site with lower than expected bacterial levels is GB 12, which probably is a reflection of the less saline, disinfected effluent from the Exeter POTW at that site. The smaller width and volume of the river in the upstream portions probably would more easily reflect influences from sources like the POTW or a tributary. The relationship between salinity and fecal coliforms was re-tested on 4/28/95, using sites at the mouths of the tributaries that were routinely sampled. The data include sites from SR-M1, downstream of GB7, upstream to SR-M19, at the Oxbow Cut just downstream from the Rt. 101 3 bridge and the Exeter POTW (Figure 5Q. The salinity decreased in order of sites going upstream, and the relationship between salinity and fecal colfforms suggests a general attenuation of fecal coliforms between SR-M19 and SR-Ml. Deviations from expected fecal coliform levels were not large and were probably a result of variability. However, loading may have occurred between sites SR-MlO and 21 (the two highest concentrations) with some dilution at site SR-M20 (the lowest value at salinity=0.5). The other site where fecal coliform concentration was greater than expected was SR-M4, but levels again decreased immediately downstream at SR-M5, suggesting that little loading was probably occurring. Water Qualily and Sources of Contamination in the Exrter River and its Tribu Bacterial and nutrient contaminants were measured at sites in the Exeter River and its tributaries from the dam (9 EXT) upstre,::-.-n to the Brentwood town line (14 EXT) (Table 4). The transect along the Exeter River goes from 9 EXT upstream to ER4, ER5, ER6 and 14 EXT (Figure 2). A transect up the Little River goes from ER I upstream to ER7 and ER2, with another site upstream on Scamen Brook at ER 3. Fecal coliforms and E. coli decreased going upstream in the Exeter River (Figure 6). In the Little River, levels also decreased going upstream. ER3 is the cleanest site, while ER2', a pipe near ER2, appears to be a potential source of contanfinants. Enterococci and C. perf7ingens concentrations were quite variable and exhibited no obvious spatial trends. Rainfall events of 0.3-0.4"/48 h occurred before two sample dates (3/22&4/4), but contaminant levels were not high (Table 4). Rainfall has significant impacts on bacterial contaminants'in this area (Jones and Langan, 1995), as presented in Table 4 for 9 EXT and 14 EXT. Nutrients were generally present at relatively low concentrations in the Exeter River area (Table 5). Ile sites with the highest levels of nitrate, ammonium and phosphate, though by small margins over other sites, were sites ER3 and 7, where bacterial contaminants were lowest (Figures 7 and 8). The data from Jones and Langan (1995) in Table 5 show that rainfall has little impact on nutrient concentrations in this area. The Exeter River and tributaries near Exeter are probably a significant source of bacterial contarninants to the tidal river, based on somewhat high levels at 9 EXT and the flow rate of the river compared to other tributaries. Bacterial levels increase along the Exeter River and Little River transects, as well as between the mouth of the Little River and the dam at 9 EXT. It appears that sources of contaminants are associated with some of the residential areas between upstream, relatively clean sites (ER3 and 14 EXT) and downstream sites. Water Qualily and Sources of Contamination in the Tributaries of the Sguamscott R Almost all of the small tributaries that empty into the Squarnscott River were sampled during the study at some point or points along their lengths (Figures I and 2). Samples could not be taken from the SR8 tributary, as a housing development has essentially incorporated the former stream bed into drainage ditches in yards. Geometric mean levels for bacterial contaminants are 4 presented in Figure 9. Levels were relatively high in some tributaries: SR25, SR 10, SR9 and SR21. Average levels of nitrate were also relatively high at some sites: SR9, SR5, SR6, SR25, and especially at SRI (Figures 10). Nitrate at SRI was always high at nearly a constant concentration (-220 jiM). Significantly, it is located very close to and is apparently part of a drainage swale that originates at the Rockingham golf course across Rt. 108 in Newmarket. SR9, with the next highest levels, is located downstream of an extensive housing development that includes some more recent construction. Ammonium concentrations were not very high, except at SR19 (Figure 11), while phosphate levels were highest at SRI I and GB7 (Figure 12), which are sites in the Squarnscott River. SR19 is downstream from a concentration of new (1990-91) residences on septic systems. Only a few samples were collected for sites SRIO, SR21 and SR25, so the data from a date where most of the sites were sampled, including these three sites, are presented in Figure 13 for the bacterial contaminants. Ile three sites with the highest levels are the same three as for the overall mean levels in Figure 9: SR9, SR25 and SRIO. For nitrate, SRI and SR9 were still high, and SR5, SR6 and SR25 were again relatively high (Table 7). Thus, it is apparently valid to include these sites in comparisons with all other sites. Rainfall events of >0.3"/48 h occurred on three occasions in spring, 1995 (4/19, 5/25 & 6/7/95) on sample dates for tributaries (Table 1). The 6/7/95 and some other individual samples suggest that rainfall could have an impact on some tributaries (Tables 6 and 7). However, it appears that temperature or some other warm season-related phenomenon also affects bacterial and nutrient concentrations. Obviously, 6/7/95 is a warm weather date, as were the July and August dates in 1994. These dates were not associated with rain events, yet had levels as high or higher than for 6/7/95 (Table 6). In between, samples had lower contaminants, even after some rainfall events earlier in the spring. Thus, rain events had no obvious, consistent impact on water quality in the tributaries. A study more focused on rainfall events would be needed to build enough data to discern effects. Some of the tributaries have relatively high concentrations of contaminants. SRI had constant high levels of nitrate, possibly associated with septic systems or some other non-apparent source (possibly seepage from old buried manure storage area), although more probably from the golf course. The constancy of high levels at this site, which is upstream of any obvious sources other than the golf course, suggests that it is coming from a strong, groundwater-bome source. Many of the sites with high nutrients, SRs 1,5,6, 9 and 19 are located at substantial distances upstream from the Squamscott River, often above marshes, and their impact may not be pronounced because of these attenuating factors. Other potential problem sites, SRs 4, 10, 11, 21, 25 and GB7 are either in the river or in close proximity, and may have bigger impacts on the river. Ile goal of this sampling and analysis is to determine whether tributaries are having negative impacts on the water quality of the Squamscott River. The following approaches help to provide evidence to make this determination. 5 Relationship Between Contamination Upstream and at the Mouths of Sguamscott Tributaries Samples were collected on two occasions at sites along the Squamscott River at the mouths of most of the tributaries (Tables 8 and 9). Many tributaries empty into the river after passing through fringing marshes in different small channels, making it difficult to locate the best sample sites. ne data are presented in Figures 14 (bacteria) and 15 (nutrients) as sites in successive points along a transect from the mouth of SRI up to the downtown Exeter site SR-M25. The fecal coliforms and E. coli again increase in concentration going up the river, with the end member, SR-M25 higher (Figure 14) than above the dam at 9 EX-F/SR14 (Table 4). The enterococci are more variable with no obvious trend. C. per so firingens levels were relatively high at me sites, probably a result of resuspended sediments in samples from these turbid tributaries at low tide. All of the sites where C. perfringens was >501100 ml were small tributaries with low flow that flowed through the fringing marshes. C. perfringens cells in estuarine water are closely associated with particulate matter (S. Jones, unpublished). Nutrient concentrations on 4/28/95 were relatively low, except for ammonium at SR-M3 (Figure 15). This site is downstream from some residences on septic systems and the fields of Stuart Farm, which have manure and inorganic nitrogenous fertilizers applied to corn and hay fields. The overall trend shows relatively higher nutrient levels at the mouths of downstream tributaries, especially ammonium at sites SR-M 1, 5, 4 and 3. These higher levels may reflect farm influences (also potentially influencing SR-M 4 and 5) or even export from the extensive marshes at the mouths of these tributaries. Both dates where tributary mouths were sampled had simultaneous sampling of the upstream tributary sites (Tables 6 and 7). Fecal coliform levels at mouths on 4/28/95 were relatively low, increasing going upstream, while enterococci were again more variable (Figure 16). Fecal coliforms levels were highest at SR3, but levels at SR-M3 were relatively low. Other sites had lower levels at upstream tributary sites, compared to mouth levels. Enterococci also did not have high tributary levels that corresponded with any elevated mouth levels. Nitrate levels were all higher in the tributaries than at the mouth sites (Figure 17), though there was little evidence of linkage/contamination of the river from the tributaries. Conversely-, ammonium levels were relatively low in the tributaries and higher at every mouth site, and SR-M3 and SR3 had the highest levels for both site types (Figure 18). Thus, the tributaries appeared to have little influence downstream in the Squamscott River on 4/28/95. Linked tributary and mouth sampling also occurred on 6/7/95 for bacterial contaminants. A rain event coincided with this date, and levels of bacteria were elevated compared to previous samples (see above discussion re: seasonal patterns). Again, the levels at mouth sites generally increased going upstream (Figure 19). The highest tributary levels were at sites SR9, SR20 and SR25. A definite linkage of high tributary to mouth levels is shown for SR25, a small linkage for SR20, and no relationship at SR9. SR25 upstream and downstream sites are in close proximity, and the tributary is near downtown Exeter, where major urban sources of bacterial contaminants appear to Pe concentrated. In all cases, the linkage between tributary sites and mouth sites does not take into account 6 the potential for contaminants to enter the tributary downstream of the upstream site. This is probably most significant for sites at greatest upstream distances and for contaminants that are mobile in the subsurface, i.e., nitrate. Contaminant Loading Estimation The best measure of potential influence of a tributary on the Squamscott River is the total loading potential from the tributary, relative to observed spatial trends in river water quality. Flow rates vary with season quite drastically in the tributaries of the Squarnscott River. Flow rate measurements were made on 6/16/95 at a time when the tributaries were not almost dry, as seen in summer, or swollen with spring rains, but probably representing average flow conditions (Figure 20). Only flow at freshwater tributary sites was measured, excluding tidal sites S Rs 3, 4, 11 and 16. SR14/9 EXT was also not measured. Ile highest flow rates were measured at SRs 25, 22, 24, 1, and 19, with substantially lower flow at SRs 5, 6, 10,21, and especially 9 and 21. Some of the high flow sites correspond to some problem sites for contaminants, like SR1 and SR25. Low flows were measured at other potential problem sites, like SR9 and SR21. Calculations of contaminant loading rates were made using flow rates and either overall mean contaminant levels or levels measured on the date closest to when flows were measured, i.e., 617/95. Loading rates calculated using 6fl/95 bacterial data showed SR25 to be the overwhelming most important potential source. Sites SR10 and SR24 were also higher loading rates for fecal coliforms and E. coli compared to the other sites. Sites SR6, SR10, SR 19 and SR22 also had relatively high loading rates for enterococci. In contrast, sites SR 9 and SR21 had high concentrations of contaminants at tributary sites but no significant loading. Using overall mean contaminant concentrations, the same three sites, SR25>>SR24 and SR10, appeared as potential problems (Figure 22). Loading rates for nutrients showed SR25 to be a consistent potential problem site, although nitrate at SR1 was the worst apparent problem (Figure 23). Other relatively high loading rate sites were SR24 and SR22 for nitrate, SR24 and SR19 for ammonium, and SR22, SR24 and SR1 for phosphate. 'Me tributaries with the largest potential to influence river water quality are, not surprisingly, the tributaries withe the highest flow rates: SRs 25, 24, 22, 1 and 19. Other sites with elevated loading were SR10 for all bacteria and, to a lesser extent, SR6 for enterococci. The calculation of loading emphasizes the importance of not drawing conclusions based solely on contaminant concentrations. The most direct connection between tributary and river water quality is at SR25, which is also a tributary site very close to the river. SRIO is also quite close to the river, an area that corresponds with some evidence of loading (Figure 5B). Other sites with elevated loading rates may not have much influence on the river because of the proximity of the sampling site relatively far upstream and the potential for attenuation to occur before the water reaches the river. Ilis is especially true in areas where the water flows through downstream marshes that can slow flow and promote plant uptake and microbial transformations of nutrients. 7 High Intensity Assessment of Contaminant Sources and Fate in a Smal Tribut= Ile last approach taken to understanding the sources and fate of contaminants in the watershed was to focus more intensively at one site, both spatially and temporally. SRI was chosen because of early measurements indicating elevated contamination with nitrate and bacteria (Tables6and7). Sites were chosen along a transect from the upstream end (SR1.1) to the mouth at the Squarnscott River (SR1.6), with SRI.2 corresponding to routine site SRI and located downstream from a house. Bacterial contamination was apparent at SR1.2/SRI, with attenuation occurring downstream to the river, especially for enterococci (Figure 24). The geometric mean concentrations of bacteria at SRI.2 were dominated by extremely high counts on 10/18/95 (Table 10). Site 1.4, located downstream from another small stream, also exhibited elevated fecal coliforms and E. coli. The upstream site was much lower than SR1.2/SR1. Nutrients exhibited unique trends (Figure 25). Both ammonium and phosphate were substantially higher downstream in the tidally-influenced water. Nitrate had very high concentrations along the whole transect, with some attenuation at 1.2 (where bacteria were highest). Nitrate concentrations at all sites remained consistently high on all sample dates (Table 11). The observed bacterial levels are consistent with expectations, based on proximity to potential sources and downstream attenuation. There are a few houses in the area upstream of 1.2, and the stream entering above 1.4 has a small pond filled with ducks, geese, swans and other birds at its head. Ile observed ammonium and phosphate levels reflect relatively low level of contamination in the freshwater portion entering tidal water with higher levels. The ammonium could also be exported from the fringing marshes through which the stream flows. However, the constant high concentrations and the lack of downstream attenuation for nitrate, as well as the lack of high levels of any other contaminant, is not consistent with typical surface-borne contamination. The major potential source upstream is the golf course, which probably fertilizes turf at a high rate. Nitrate is a very mobile anion in groundwater and it is quite probable that the groundwater in the area is contaminated with nitrate from nitrogen fertilizer applied at the golf course. The nitrate does not have much apparent impact on the river, except that the highest level measured at GB7 occurred in October, 1994, at the same time as sampling for the SRI sites. Sources and 1=acts- of Susl&nded Sediments in the Squamscott River Total suspended solids (TSS) were also measured at the same sites and times as nutrients and bacteria (Table 12). The TSS decreased going upstream from GB7 to GB 13 (Figure 28). Ile levels in the Exeter River sites were substantially lower than downstream levels but near to levels at the upstream GB 13 site observed in the river (Figure 27). The other tributaries around the watershed had varying TS S levels (Figure 26). The highest levels were observed at SR 11, GB7 and SR3, which are all sites either in the river (SRI I and GB7) or heavily influenced by tidal waters (SR3). The average levels for the other sites all had TSS levels that were lower than average levels at downstream sites (Figure 28). In contrast to all other samples, TSS levels in 8 tributary mouth samples were high (Figure 29). As previously mentioned, and as suggested by elevated levels of C. perfringens in the same samples, sampling at the tributary mouths is nearly impossible to accomplish by boat without disturbing the readily resuspendable sediments and contaminating the samples. Thus, the measured levels of TSS are probably not reflective of water concentrations upstream. However, all of the tributaries that flow through the fringing marshes and sampled by boat had obviously turbid water. Resuspension of sediments in the river, as well as at these sites with flowing water entering the river, is probably the governing mechanism causing high levels of TSS in the river. The SR1.1-1.6 samples further illustrate this, as upstream water had very low TSS levels and the sites in the mouth of the tributary had relatively high levels, probably even higher than what was occurring in the river (Figure 30). Evaluation of Previously Identified Critical Factors and Landuse Interpretatoon Landuse Data and InIgWtation The Squamscott River watershed comprises 11,940 acres within portions of Exeter, Stratham and Newfields. The focus of this study was directed at the areas that would most likely impact the Squamscott River, meaning areas between the river and Route 108 on the east and Route 85 on the west. Ile predominant landuses are forest, undeveloped land and open space. Other landuses include clusters of residential development in Stratham and Newfields, and numerous single family houses throughout the watershed. Agricultural areas include cropland and dairy farms, located primarily in the Stratharn portion of the watershed (Figure 3 1). A large commercial areas exists along Route 108 in Stratham, and Exeter. The majority of the watershed is unsewered, but two distinct areas are sewered: the commercial area of Stratharn with Exeter, and a portion of Newfields, at the center of town. There are extensive tributaries to the Squamscott and Exeter rivers throughout the watershed. A GIS was used to manipulate available spatial data to identify and quantify specific landuses with high potential for nonpoint source pollution. Many potential data layers were available. However, the soils and landuse data were most useful, and resulted in identification of agricultural areas that were on poorly drained soils (Figure 32) and nonsewered residential areas on soils poorly suited for septic systems (Figures 34 and 35). These data were useful, when combined with USGS maps that show residential areas, to determine changes in landuse that can help detennine ages of septic systems and other information. Ile GIS data were limited in that the 1986 data did not have farming data, and the 1991 data did not cover Newfields. The GIS also allowed for quantification of residential and agricultural areas with potential for nonpoint source pollution, based on soils and proximity to a calculated 75 foot buffer. The percentage of the watershed with residential homes on soils with low or very low suitability for septic systems increased from 1.9% in 1986 to 6.8% in 1991, even though the 1991 coverage only included half of the watershed. The percentage of these homes that fell 9 within the 75 foot stream buffer decreased from 4.8% to 3.8%, suggesting that newer homes may have been built less frequently within the buffer. Agricultural I'and on poorly drained soils covered 2. 1 % of the watershed in 199 1, and the percentage that fell within the 75 foot buffer was 3.5%, similar to the residential areas. However, because of the smaller area covered and the fact that pollution-generating activities are not necessarily located within these areas on farms, the potential for pollution is probably much less significant compared to residences on septic systems. Additional work was necessary to fill data gaps and to update landuse information to the present. This was accomplished by quantifying building permits in the watershed during 1990 through 1994 (Figure 33), groundtruthing areas around tributaries to confirm the existence of houses, and to identify other potential contamination sources (Figure 36). No farms of concern were found in Newfields, which was not included in the 1991 farmland data. Using a combination of existing residences on USGS maps, the 1986 and 1991 GIS data, and the new construction information up to 1994, the ages and general types of septic systems could be assumed. Assessment of Critical Factors The critical factors identified in a previous report (Jones and Langan, 1994a) for this type of study were soils and their suitability for specific uses, proximity of potential sources to surface water, farms with animals or manure spreading on land, and to a lesser extent, age and type of septic systems. The most important potential sources in the Squamscott River are also residential homes with septic systems and farms. These factors were considered during the whole process of sample site selection and landuse data collection and interpretation. Based on soils and landuse data, the areas in the watershed that are potential problem areas are near SR3, SR4, SR5, SR6, SR8 (not sampled; M8 and GB9 were), SR9, SR10, between SR9 and SR10, SR19, SR20 and SR21. The areas identified as having potential for problems using the soils and landuse data were sampled for water quality assessment, as previously described. The sites that had high levels of contaminants included most of the areas predicted to be problems, including SR3, SR5, SR6, SR9, SRIO and SR19. The GIS analysis did not include critical areas near two of the most important sites: SRI and SR25 (see METHODS). The areas that had elevated contaminant levels and were predicted to be problems that also were significant as far as loading potential to the river included sites SR9, SRIO and SR19. Most sites had septic systems of different ages. Sites SRI, SR22 and SR24, which had high loading rates, were not predicted to be problem areas, using the existing digitized data. It is quite possible given 1991 or newer landuse data that these sites could also be included. However, no new construction was apparent based on review of building permits in these areas (Figure 33). The sources of these contaminants, mostly nutrients, may be something other than residential homes or farms. For example, the golf course in Newmarket upstream of SRI is a probable major source of nitrates at SRI, and would not have been included in this analysis. 10 Some of the loading from the potential problem areas would be attenuated as streams flowed through downstream marshes or ponds. This would be most important at SRs 3-6, where extensive salt marshes exist. SR9 flowed through a dense forested area and was quite a distance upstream from the river, while SRs 19-24 flowed through smaller downstream fringing salt marshes. There is not much detention of flow for the tributaries downstream from SRIO and SR25, and these are in fact major potential loading sources of contaminants. This approach was useful for predicting sites with potential significant impacts on the river water quality. Added coverages, while probably not adding much new critical information, would be useful for presenting a comprehensive assessment of potential sources. However, the whole approach, including the landuse assessment, water quality analysis and flow rate measurements, are necessary to formulate a coherent assessment of nonpoint source pollution in any coastal watershed. The potential usefulness for modelling such areas is increasing as models are tested and modified for these applications. We are presently cooperating with NOAA/SEA Division in their modelling efforts that are focusing on the whole Piscataqua/Great Bay Estuary. They are applying the SWAT model to predict nonpoint source pollution. Assessment of Suspended Sediment Loadong to the Watershed Data from previous studies has raised concerns about the levels of TSS in the Squamscott River (Langan and Jones, 1995). Ile trend for TSS at Chapmans Landing from 1989 to 1992 was of concern, because relatively high levels persisted over that time period (Figure 37). Levels dropped in 1993, an unusually dry year, but remained relatively low in 1994, a more normal year. The analyses done in this study suggest no obvious sources of TSS to the Squarnscott River from any tributaries or shoreline sites. Thus, anthropogenic sources of TSS are probably not significant in this watershed, leaving natural processes as the source of turbidity and solids in the river. Further investigation of potential sources was done as part of this study. Potential sources other than residential home construction are summarized in Table 13. Figure 38 relates to road construction and salting in the watershed. No obvious significant sources of solids is apparent from review of road construction (Table 13) and measured TSS levels at sampling sites. Road salting data were general and no information for specific sites was available. The total building permits in the three towns that were on file for 1990 through 1994 are summarized in Figure 39, and locations are presented in Figure 33. Numerous analyses of building permit numbers in different areas and TSS levels at GB7 were made with no evidence of any relationship between the permits and TSS levels. Comparing the TSS levels in Figure 37 with the building permits in Figure 39 shows a negative relationship with time: there were more building permits in 1993 and 1994 compared to previous years, while TSS levels were lowest in these two years. There are no apparent problem areas for loading of TSS in the watershed. 'Me elevated levels measured in the river are probably internally-driven processes, resulting in resuspension of bottom sediments on a consistent basis. This was illustrated by some of the results from this study, where high TSS levels were measured at the mouths of small tributaries at low tide. This conclusion was only made possible by the measurement of water quality in the tributaries, mouths, and along the river. 12 REFERENCES Jones, S.H. 1990. Impact of Runoff Events on Water Quality in Great Bay. Final Report to the NH Office of State Planning, NH Coastal Program. Jones, S.H. and R. Langan. 1993. Oyster River Nonpoint Source Pollution Assessment. Final Report to the NH Office of State Planning, NH Coastal Program. Jones, S.H. and R. Langan. 1994a. Land Use Impacts on Nonpoint Source Pollution in Coastal New Hampshire Watersheds. Final Report to the NH Office of State Planning, NH Coastal Program. Jones, S.H. and R. Langan. 1994b. Mitigation of Agricultural Contaminants of Estuarine Water Using Constructed Wetlands. Final Report to the NH Office of State Planning, NH Coastal Program. Jones, S.H. and R. Langan. 1995. Assessment of Nonpoint Source Pollution in Tributaries Entering Great Bay. Final Report to the NH Office of State Planning, NH Coastal Program. Lachat Instruments. 1991. Operating manual for the Quick Chem Autoanalyzer Lachat Instruments. Milwaukee, Wisconsin. Langan, R. 1992 a. UNH JEL Standard operating procedure for water sampling for suspended solids, chlorophyll, and nutrients. JEL SOP 1.05. In: Standard ol2erating 12rocedures and field methods used for conducting ecological risk assessment case studies. Mueller et al. eds. 1992. USEPA, US Navy (NRaD) Technical Document 2296. Langan, R. 1992 b. UNH JEL Standard operating procedure for water sample filtration and analysis of total suspended solids, chlorophyll and phaeopigments. JEL SOP 1.06. In: Standard - =edures and field methods used for conducting ecological risk assessment case studies, Mueller et al. eds. 1992. USEPA, US Navy (NRaD) Technical Document 2296. Langan, R. and S.H. Jones. 1995. A Monitoring Plan for the Great Bay Estuarine Research Reserve: Final Report for 1994. NOAA Technical Memorandum, NOS MEMD# NA170R0182- 03. Strickland, J.D.H. and T.R. Parsons. 1968. A Practical Handbook of Seawater Analysis. Fisheries Research Board Of Canada, Ottawa, I 968.Strickland, J.D.H. and T.R. Parsons. 1968. A Practical Handbook of Seawater Analysis. Fisheries Research Board Of Canada, Ottawa, 1968. 13. Table 1. Rainfall at Durham, NH gauging station on day prior to sampling and cumulative of two days on day of sampling in different areas. RainfaU (inches) Day of 24 h Total rainfaH Date (cumulative) previous for month Sampling area(s) 7/19/94 0 0 July=2.20 SR tribs 8/2/94 0 0 Aug.=4.05 SR tribs 8/16/94 0 0 SR tribs 9/12/94 0 0 Sept=7.26 SR tribs 9/27/94 0.14 0 SRI 10/6/94 0 0 Oct.--0.19 SRI 10/11/94 0 0 GB7-13 10/12/94 0 0 SRI 10/18/94 0 0 SRI 10/20/94 0.06 0.02 SR tribs 10/25/94 0 0 Nov.=2.88 GB7-13 11/8/94 0.09 0.09 ER 11/15/94 0 0 ER & SR tribs 12/6/94 1.16 1.12 Dec.=5.55 ER 3/22/95 0.31 0.12 Mar.=1.87 ER 4/4/95 0.37 0 Apr.=1.85 ER 4/19/95 0.31 0 SR tribs 4/26/95 0 0 ER & SR tribs 4/28/95 0 0 SR trib mouths 5/25/95 0.43 0.04 May =2.74 SR tribs 6/1/95 0 0 June=1.92 SR tribs 617/95 0.3, 0 SR tribs & mouths 6/16/951 0.29 0.24 trib flow rates 14 Table 2. Concentrations (per 100 MI) of bacterial indicators at sites from Chapman's Landing (GB7) to just above the Exeter POTW (GB13). Fecal coliforms Sites GB 7 GB8 GB9 GB 10 GB 11 GB 12 GB 13 10/11/94 9 26 43 68 63 81 70 10/25/941 37 370 640 785 645 405 620 Geo. Mean 18 99 165 231 202 181 208 E. coli Sites GB 7 GB8 GB9 GBIO GB 11 GB 12 GB 13 10/11/941 9 24 41 30 64 78 52 10/25/94 21 220 335 465 240 200 280 Geo. Mean 14 72 118 118 124 125 121 Enterococci Sites GB 7 GB8 GB9 GB10 GBII GB12 GB13 10/11/94 10 11 15 21 29 31 28 10/25/94 25 47 64 39 42 54 40 Geo. Mean 16 23 31 28 35 41 33 C. perfringens Sites GB 7 GB8 GB9 GBIO GBI1 GB12 GB13 10/11/941 7.0 9.0 13 19 22 13 20 10/25@, 0.5 5.0 4.5 3.5 1.5 0.5 0.5 Geo. Mean 1.9 6.7 7.7 8.2 5.7 2.5 3.2 15 Table 3. Concentrations of nutrients at sites from Chapman's Landing (GB7) to just above the Exeter POTW (GB 13). Ammonium (gm) Sites GB 7 GB8 GB9 GBIO GBII GB12 GB13 10/11/941 4.89 4.59 2.55 1.24 0.80 1.47 10/25/941 7.76 _- 6.93 8.41 11.00 9.31 9.93 9.68 Average 6.32 5.76 5.48 6.12 5.05 5.70 9.68_ Nitrate (gm) Sites GB 7 GB8 GB9 GB10 GBII GB 12 GB 13 10/11/941 17.48 27.27 21.78 31.27 29.12 21.39 10/25/941 24.99 18.86 24.88 20.61 24.11 38.42 36.87 Average 21.24 23.06 23.33 25.94 26.61 29.91 36.87 Phosphate (gm) Sites GB 7 GB8 GB9 GB10 GBI1 GB12 GB13 10/11/941 2.98 2.96 3.09 2.84 2.93 2.18 10/25/941 2.69 3.15 3.34 3.25 3.19 3.99 3.32 Average 2.83 3.06 3.21 3.05 3.06 3.08 3.32- 16 Table 4. Bacterial indicator concentrations (per 100 ml) at sites in the Exeter River and its tributaries. FECAL COLIFORMS DATE 9-T;YT 9-EXT* ER-1 ER-2 ER-2' ER-3 ER-4 ER-5 ER-6 ER-7 14-EXT 14-EXT* 11/8/94 57.5 wet/dry 208 97.5 65 1 113 40 20 22.5 wet/dry 11/15/94 32.5 condition 95 62.5 77.5 0.75 47.5 35 27.5 8.5 condition 12/6/94 357 levels 723 585 61 893 950 870 169 levels 3/22/95 from 65 15 0.4 25 25 50 15 from 4/4/95 290 other 10 20.5 3 37 22 22 17 other 4/26/95 study 16.5 10 1 24 11 37 8 study Geo. mean 118 149/31 73 47 71 2 69 45 52 13 32 42/16 E. COLI DATE 9-EXT 9-EXT* ER-1 ER-2 ER-2' ER-3 ER-4 ER-5 ER-6 ER-7 14-EXT 14-EXT* 11/8/94 40 wet/dry 208 82.5 47.5 1 113 35 20 22.5 wet/dry 11/15/94 32.5 condition 95 62.5 67.5 0.75 47.5 35 27.5 8.5 condition 12/6/94 320 levels 710 585 61 833 905 870 169 levels 3/22/95 ftom 25 12.5 0.45 25 25 37.5 10 from 4/4/95 97.5 other 5 16 0.8 33.5 22 18 15 other 4/26/95 study 15 8 1 23 9 36 7 study Geo. mean 180 111124 55 41 57 2 66 42 48 10 32 33/9 ENTEROCOCCI DATE 9-EXT 9-EXT* ER-1 ER-2 ER-2' ER-3 ER-4 ER-5'ER-6 ER-7 14-EXT 14-EXT* 11/8/94 11.3 wet/dry 25 14 66 30.5 30 6.3 8.8 5 wet/dry 11/15/94 3 condition 21.3 48 16 34 56.3 24 21.5 14 condition 12/6/94 78 levels 296 254 223 205 192 468 418 levels 3/22/95 from 35 39 10 30 55 21 47.5 from 4/4/95 other 175 51.25 30 2.5 3 4 211.25 other 4/26/95 study 2.5 2 1 8.75 2.752 2.5 study Geo. mean 14 41/14 37 30 32 20 25 15 16 29 _31 22/11 C PERFRINGENS DATE 9-EXT 9-EXT* ER-1 ER-2 ER-2' ER-3 ER-4 ER-5 ER-6 ER-7 14-EXT 14-EXT* 11/8/94 8.5 wet/dry 11 <0.5 <0.5 14.5 19.5 1.5 2.5 1.5 wet/dry 11/15/94 10 condition 8.5 23.5 12 5 31 5 1.25 3.25 condition 12/6/94 41 levels 62.5 44.8 45.5 36.5 45 37.3 45.5 levels 3/22/95 from 0.45 0.5 0.45 0.45 0.2 0.5 0.45 from 4/4/95 10 other 20 13 15 10 10 6 45.5 other 4/26/95 study 5 8 7.5 5 2 12 study Geo. mean 14 NA 8 9 12 8 10 4 3 6 6 NA Fecal coliforms, E. coli and enterococci also measured at 9&14 EXT as pan of Jones and Langan (1995) study. 17 Table 5. Dissolved inorganic nutrient concentrations at sites in the Exeter River and its tributaries. NH4 @M DATE 19-EXT 9-EXT* ER-I ER-2 ER-3 ER-4 ER-5 ER-6 ER-7 14-EXT 14-EXT* 12/6/94 5.12 wet/dry 2.77 2.08 2.55 5.36 3.47 5.91 49.01 wet/dry 3/22/95 levels; 2.47 1.05 1.62 2.96 ' 1.76 1.44 2.21 levels; 4/4/95 1.26 other 2.81 1.69 2.01 1.51 5.04 1.30 3.24 other 4/26/95 study 2.77 2.70 2.25 3.01 2.76 2.20 2.28 study Average 3.19 3.513.5 2.71 1.88 2.11 3.21 3.26 2.71 2.57 49.015.613.5 N03 4M DATE 9-EXT 9-EXT* ER-I ER-2 ER-3 ER-4 ER-5 ER-6 ER-7 14-EXT 14-EXT* 12/6/95 19.94 wet/dry 6.32 10.57 11.61 14.89 9.73 15.86 33.13 wet/dry 3/22/95 levels; 2.88 1.05 7.10 4.33 4.95 5.32 3.92 levels; 4/4/95 5.70 other 6.85 5.70 14.38 7.51 4.89 6.98 20.96 other 4/26/95 study 5.71 0.86 3.23 3.01 6.24 4.36 6.06 study Average 12.82 6.3/4.2 5.44 4.54 9.08 7.44 6.45 8.13 10.31 33.13 6.3/4.2 P04 pM DATE 19-EXT 9-EXT* ER-I ER-2 ER-3 ER-4 ER-5 ER-6 ER-7 14-EXT 14-EXT* 12/6/95 0.517 wet/dry 0.360 0.463 0.247 0.317 0.282 0.290 0.463 wet/dry 3/22/95 levels; 0.266 0.255 0.319 0.192 0.168 0.164 0.217 levels; 4/4/95 0.116 other 0.228 0.244 0.174 0.109 0.106 0.074 0.266 other 4/26/95 study 0.394 0.304 0.236 0.111 0.101 0.076 0.332 study Average 0.316 .31/.24 0.312 0.316 0.244 0.182 0.164 0.151 0.272 0.463 .161.16 18 Table 6. Concentrations (per 100 ml) of bacterial indicators at sites in tributaries to the Squamscott River. Enteroccocci Site 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 GB 7 7/19/94 109 231 148 660 1300 43 510 294 34 8/2/94 135 248 258 1100 6400 0 15 925 185 9 8/16/94 288 2015 610 7500 231 7400 485 9/12/94 - 0 1100 210 1900 0 0 0 0 3 10/20/94 137 3 0 18 26 33 8 10 10 7 11/15/94 19 15 35 34 175 15 5 0 95 8 4/19/95 10 4 2 29 11 11 26 6 4/26/95 2 17 2 4 3 8 5 3 10 5/25/95 75 90 288 81 149 408 690 40 88 250 250 54 49 1390 6/1/95 5 430 25 430 740 180 50 15 14 75 50 6 200 13 6/7/95 265 880 840 2350 3760 2540 88 140 612 1545 220 400 192 2960 59_ Geo. Mean 43 35 288 50 150 368 681 9 16 91 54 140 41 38 937 12 C Perfringens Site 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 GB 7 7/19/94 0 9 31 0 193 0 5 12 2 12 8/2/94 16 6 22 40 1235 39 3 0 1 4 8/16/94 7 2 60 0 300 15 17 0 0 7 9/12/94 15 105 7 673 79 7 7 4 18 10/20/94 5 14 6 8 15 66 7 9 7 11 11115194 6 4 49 1 10 2 0 0 0 2 4/19/95 22 8 6 6 16 137 17 21 14 4/26/95 3 3 4 2 3 98 4 2 4 Geo. Mean 5 6 20 3 65 20 5 2 2 7 19 Table 6. Concentrations (per 100 ml) of bacterial indicators at sites in tributaries to the Squamscott River. Fecal Coliforms Site 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 OB 7 7/19/94 98 38 114 233 1300 303 93 685 456 33 8/2/94 123 18 165 110 7100 110 91 2490 75 25 8/1604 50 0 300 103 400 65 268 1100 18 16 9/12/94 0 93 53 2100 65 355 9 38 10/20/94 34 43 8 74 0 230 124 20 28 28 11/15/94 80 61 9 11 545 30 28 15 40 37 4/19/95 26 166 31 9 27 72 116 20 56 4/26/95 8 143 11 12 5 43 68 6 4 5/25/95 19 1740 140 69 49 83 26 83 6/1/95 5 1100 18 63 1150 300 335 110 9 15 50 10 70 600 41 6n/951 165 540 280 235 6480 2100 220 140 283 1700 900 130 350 6100 98 Geo. Mean 37 51 140 49 53 265 794 108 98 40 120 212 36 157 1913 35 E. coli Site 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 GB 7 7/19/94 85 27 105 161 4300 247 80 669 416 30 8/2/94 120 14 163 95 7100 105 86 2310 7@ 25 8/16/94 50 0 243 88 400 63 223 800 20 15 9/12/94 0 23 35 2100 18 53 145 23 4 10/20/94 32 43 2 32 0 190 108 20 27 26 11/15/94 80 57 8 11 540 28 28 15 40 37 4/19/95 16 159 30 6 27 45 75 20 55 4/26/95 3 118 10 6 5 40 50 3 4 5/25/95 19 1153 28 69 49 60 25 65 6/1/95 0 1100 18 63 1040 250 190 70 6 5 0 10 30 100 15 6/7/95 165 540 270 225 6220 1900 220 110 259 1565 610 130 350 5740 84 Geo. Mean 24 46 28 36 40 294 689 80 75 34 87 16 39 102 758 22 20 Table 7. Concentrations of nutrients at sites in tributaries to the Squamscott River. Ammonium (gm) Site 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 GB 7 7/19/94 4.16 68.90 4.99 7.06 5.51 15.33 4.80 4.26 4.43 9.57 8/2/94 4.36 0.44 7.42 5.73 7.77 0.20 4.86 6.11 4.75 2.59 8/16/94 12.15 1.21 5.19 5.90 5.49 3.74 4.88 5.01 1.81 2.08 9/12/94 1.32 4.89 1.49 1.28 1.60 0.86 0.76 1.51 1.71 2.72 10/20/94 1.01 29.64 0.19 0.75 0.22 13.87 0.91 19.82 0.06 6.89 11/15/94 0.80 5.66 0.97 1.97 1.91 5.07 3.22 1.62 1.55 3.25 4/19/95 9.68 5.08 3.55 2.62 1.39 14.34 1.75 1.48 1.64 4/26/95 1.81 7.57 1.77 2.29 1.98 9.33 3.84 1.58 2.00 5/25/95 2.04 14.38 2.31 1.91 1.53 1.94 3.26 17.20 50.37 30.21 1.19 1.49 2.46 4.60 6/1/95 1.41 7.50 1.69 7.81 4.65 4.23 5.88 14.01 43.68 1.75 1.94 3.64 4.51 5.66 8.47 6n1951 10.93 25.84 1.60 3.21 13.17 8.42 17.92 130.94 35.35 18.89 50.74 5.86 24.17 28.33 Average 4.52 15.55 2.31 2.80 3.65 4.15 5.30 8.65 17.02 43.13 8.39 17.96 2.63 10.38 12.86 5.08 Nitrate (@Lm) Site 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 GB 7 7/19/94 215.93 8.03 50.38 56.05 206.13 4.87 0.28 - 9.79 4.36 3.62 8/2/94 235.36 0.30 48.09 61.17 35.98 1.54 0.00 12.77 5.81 0.40 8/16/94 228.17 2.74 41.24 75.72 220.78 1.35 0.14 9.18 5.91 1.31 9/12/94 244.21 4.09 48.03 69.61 122.92 1.71 0.51 10.23 4.11 1.98 10/20/94 231.71 14.40 69.46 25.78 146.14 22.08 8.91 8.29 6.02 20.03 11/15/94 259.11 10.74 75.45 35.09 162.34 20.34 4.59 7.23 8.17 4.76 4/19/95 179.01 12.43 37.84 25.72 95.29 7.65 3.66 16.30 5.32 4/26/95 201.67 14.04 29.85 18.67 90.95 7.62 4.88 9.60 4.80 5/25/95 222.26 19.91 6.38 14.79 10.13 59.89 4.37 5.58 2.50 5.31 1.14 2.48 4.05 14.20 6/1/95 248.48 6.61 27.33 23.20 135.31 13.36 7.96 6.75 3.93 15.16 5.91 4.95 12.55 33.54 6.32 6n195 200.11 10.07 18.23 18.50 59.80 10.27 12.23 5.58 2.70 1.68 6.74 6.42 10.45 27.49 Average 224.18 9.40 6.38 41.88 38.15 121.41 9.34 8.73 3.72 3.04 9.59 4.60 5.30 9.02 25.08 5.49 21 Table 7. Concentrations of nutrients at sites in tributaries to the Squamscott River. Pbosphate (@tm) Site 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 -GB 7 7/19/94 0.27 0.35 0.28 0.39 0.45 3.59 0.32 0.63 0.23 1.19 8/2/94 0.26 0.17 0.18 0.31 0.26 0.03 0.38 0.86 0.28 0.22 8/16/94 0.15 0.02 0.11 0.17 0.15 2.54 0.10 0.65 0.03 0.97 9/12/94 0.32 1.22 0.28 0.24 0.28 0.78 0.19 0.84 0.23 2.26 10/20/94 0.37 0.72 0.17 0.15 0.14 3.98 0.35 0.48 0.25 2.61 11/15/94 0.30 1.46 0.17 0.17 0.07 1.63 0.38 0.59 0.39 1.23 4/19/95 0.16 0.17 0.03 0.07 0.08 0.33 1.16 0.08 0.09 0.08 4/26/95 0.24 0.48 0.10 0.10 0.38 0.87 0.15 0.19 0.14 5/25/95 0.47 0.73 0.95 0.26 0.22 0.56 0.78 0.38 0.41 0.50 0.47 0.47 0.24 0.46 6/1/95 0.37 0.71 0.37 0.33 0.70 0.69 1.55 0.50 0.45 0.53 0.64 0.68 0.42 0.60 1.48 6n195, 0.50 0.77 0.38 0.39 0.69 0.71 1.68 0.50 0.38 0.48 0.54 0.49 0.31 0.57 Average 0.31 0.62 0.95 0.21 0.23 0.34 0.72 1.70 0.40 0.41 0.53 0.55 0.30 0.32 0.54 1.26 22 Table 8. Concentrations (per 100 ml) of bacterial indicators in the Squarnscott River at the mouths of small tributaries. Fecal coliforms Sites MI M5 M4 M3 M24 M22 M8 M9 M21 M20 MIO M19 SR17 M16 M25 4/28/95 15 16 45 28 40 35 48 40 83 43 78 64 98 6n/951366 386 98 510 745 588 370 885 850 2 1235 4310 Geo. mean 74 79 66 118 40 161 48 153 175 195 78 233 2 348 4310 E. coli Sites MI M5 M4 M3 M24 M22 M8 M9 M21 M20 MIO M19 SR17 M16 M25 4/28/95 13 10 30 23 35 5 22 28 68 29 48 33 58 6n/951344 350 84 480 610 570 325 868 825 2 1170 4215 Geo. mean 66 59 50 104 35 55 22 126 149 159 48 166 2 260 4215 Enterococci Sites -MI M5 M4 M3 M24 M22 M8 M9 M21 M20 MIO M19 SR17 M16 M25 4/28/951 4 14 8 4 32 5 8 6 13 20 14 19 18 617/95 158 306 59 307 400 386 454 600 296 1 746 1615 Geo. mean 24 64 22 35 32 42 8 48 77 108 14 74 1 114 1615 C. perfyingens Sites MI M5 M4 M3 M24 M22 M8 M9 M21 M20 MIO M19 SR17 M16 M25 4/28/95 23 24 22 76 109 122 45 94 64 71 89 42 6f7/951 Geo. mean 23 24 22 76 109 122 45 94 64 71 89 42 23 Table 9. Concentrations of nutrients in the Squamscott River at the mouths of small tributaries. Ammonium (@tm) Sites MI M3 M4 M5 M8 M9 MIO M16 SR17 M19 M20 M21 M22 M24 M25 4/28/951 8.85 18.60 10.41 9.72 6.61 5.11 6.40 5.77 6.11 6.41 6.24 7.20 Nitrate (@tm) Sites MI M3 M4 M5 M8 M9 MIO M16 SR17 M19 M20 M21 M22 M24 M25 4/28/95T 5.39 8.36 9.55 9.33 8.37 6.67 7.25 5.24 5.L89 6.92 8.57 9.98 Phosphate (gm) Sites MI M3 M4 M5 M8 M9 MIO M16 SR17 M19 M20 M21 M22 M24 M25 M 0.926 1.066 0.803 0.777 1.120 1.107 1.127 1.101 1.285 1.123 1.137 1.012 24 Table 10. Concentrations (per 100 ml) of bacterial indicators along a small tributary in Newmarket and New-fields going downstream to the Squimscott River. Fecal coliforms Site 1.1 1.2 1.3 1.4 1.5 1.6 9/27/94 50 55 185 300 500 10/6/94 13 33 45 100 55 25 10/12/94 45 50 23 33 10/18/941 76 3140 81 86 96 75 Geo. Mean 36 177 74 107 88 40 E. coU Site 1.1 1.2 1.3 1.4 1.5 1.6 9/27/94 46 53 180 270 305 10/6/94 8 28 45 90 50 20 10/12/94 40 50 23 31 10/18/94 72 2960 71 75 85 36 Geo. Mean 29 163 69 98 74 28 Enterococci Site 1.1 1.2 1.3 1.4 1.5 1.6 9/27/94 70 40 105 10/6/94 28 40 28 23 50 25 10/12/94 18 12 14. 19 10/18/94 104 1245 74 92 80 101 Geo. Mean 54 223 40 31 49 36 C. perfYingens Site 1.1 1.2 1.3 1.4 1.5 1.6 9/27/94 7 10 15 15 25 10/6/94 6 15 13 17 11 10 10/12/94 5 9 12 13 10/18/94 4 54 5 9 13 11 Geo. Mean 5 20 8 12 14 11 25 Table 11. Concentrations of nutrients along a small tributary in Newmarket and Newfields going downstream to the Squarnscott River. Ammonium (gm) Site 1.1 1.2 1.3 1.4 1.5 1.6 9/27/94 0.54 2.29 3.84 3.19 5.90 4.42 10/6/94 3.18 2.17 2.66 4.47 9.72 11.57 10/12/94 1.98 2.35 1.89 3.17 5.68 6.64 10/18/94 1.42 0.64 3.47 1.99 6.63 6.28 Average 1.78 1.86 2.96 -3.21 6.98 7.23 Nitrate (gm) Site 1.1- 1.2 1.3 1.4 1.5 1.6 9/27/94 183.4 49.9 122.3 119.4 97.4 117.9 10/6/94 216.5 53.6 165.5 161.2 76.3 14.3 10/12/94 220.6 56.8 182.9 172.9 137.4 145.6 10/18/94 237.6 63.5 183.4 180.5 125.4 122.6 Average 214.5 55.9 163.5 158.5 109.1 100.1 Phosphate (gm) Site 1.1 1.2 1.3 1.4 1.5 1.6 9/27/94 0.455 0.400 0.661 0.752 1.157 1.048 10/6/94 0.318 0.238 0.469 0.568 1.271 1.811 10/12/94 0.326 0.215 0.449 -0.496 0.856 1.125 10/18/94 0.297 0.210 0.376 0.462 1.005 1.442 Average 0.349 0.266 0.489 0.570 1.072 1.356 26 Table 12. Total suspended solids (mg/L) at all sample sites in the Exeter/Squamscott watershed: 1994-95 Total Suspended Solids (mg/L) in tributaries to the Squamscott River DATE SR- 1 SR-3 SR-4 SR-5 SR-6 SR-9 SR-10 SR-11 SR-14 SR-19 SR-20 SR-21 SR-22 SR-24 SR-25 GB7 7/19/94 16.40 13.20 2.00 1.20 3.80 149.00 1.20 7.20 17.40 8/2/94 3.00 51.00 3.60 9.40 97.20 55.33 2.20 4.40 0.40 49.00 8/16/94 1.80 52.00 4.20 0.20 3.40 44.50 1.00 2.80 0.40 18.60 10/20/94 1.20 13.20 3.20 1.00 0.80 18.60 1.80 1.60 3.00 13.80 11/15/94 0.40 25.20 2.00 0.40 0.40 45.00 2.20 0.80 1.80 37.60 4/19/95 3.60 24.20 1.80 3.80 4.00 31.14 2.60 13.60 3.80 4/26/95 1.00 6.20 1.40 0.80 5.80 33.70 1.60 2.20 3.20 5/25/95 4.80 11.20 12.75 2.60 2.80 4.6.0 13.40 2.60 4.60 16.60 12.60 4.00 32.80 6.20 6/1/95 2.60 8.20 1.60 1.40 2.20 3.60 32.20 1.40 5.40 5.60 15.00 2.00 3.80 3.20 12.60 6R/95 5.40 11.60 5.40 15.60 12.60 27.80 31.00 3.40 22.20 10.80 8.80 5.60 5.60 10.00 Mean ------------ J-4.02 21.60 12.75 2.78 3.66 13.48 14.93 48.94 2.00 10.73 6.56 12.13 2.69 14.07 6.47 24.83 Total Suspended Solids (mg/L) on the Exeter River and tributaries DATE ER1 ER2 ER3 ER4 ER5 ER6 ER7 EX19 ER14 11/16/94 2.80 4.22 4.67 2.30 4.30 5.20 5.10 3.10 12/6/94 5.89 4.20 7.70 8.30 5.11 4.56 18.00 4.44 3/22/95 2.60 2.60 7.00 2.20 3.40 2.00 5.20 4/4/95 3.00 2.00 20.17 1.44 2.00 1.33 3.67 1.56 4/26/95 2.40 4.40 26.60 2.80 1.80 2.20 3.20 Mean 3.34 3.48 '13.23 3.41 3.32 3.06 4.02 8.22 3.77 27 Table 12. Total suspended solids (mg/L) at all sample sites in the Exeter/Squamscott watershed: 1994-95 TSS in a transect from Chapmans Landing to the Exeter POTW DATE GB7 GB8 GB9 GB10 GBII G1312 GB13 10/11/94 20.40 17.60 18.00 23.00 21.33 20.00 10/25/94 16.20 11.40 11.60 11.40 10.00 9.60 12.80 Mean 18.30 14.50 14.80 17.20 15.67 14.80 6.40 TSS at the mouths of tributaries Entering the Squamscott River DATE SRM1 SRM3 SRM4 SRM5 SRM8 SRM9 SRMIO SRM19 SRM20 SRM21 SRM22 SRM24 4/28/95 87.33 60.67 76.00 137.50 47.00 47.60 61.00 36.00 36.33 34.80 123.00 37.20- TSS concentration along a small tributary in Newmarket and Newfields going downstream to the Squamscott River DATE SRI-I SRI-2 SRI-3 SRI-4 SRI-5 SRI-6 9/27/94 0.80 0.20 12.80 15.20 26.60 32.33 10/6/94 1.62 3.50 5.40 5.80 17.80 24.60 10/12/94 1.20 0.40 4.40 8.20 22.80 45.00 10/18/94 2.60 1.40 4.40 4.20 11.80 22.60 Mean 1.56 1.38 6.75 8.35 19.75 31.13 28 Table 13. All suspected sources of suspended solids loading to the Squamscott River watershed. Road Construction Within the Squarnscott Watershed 1988-94. Town Road Year Map Stratharn Peninsula Drive/Winding Brook Started 1985, done in phases until fall 1994 3 Stratharn Parsonage Hill Development/Turnbeffy Started 1990 to present 3 Stratharn Unda Lane Started spring 1990, finished 1992 5 Stratharn Morning Star Drive/Tucker's Trail Started spring 1992, finished summer 1992 5 Stralharn Greta'Way Started summer 1993, finished summer 1994 1 Stratharn Boat Club Drive (end of River Rd) Staited July 1994 to present I Exeter Captaih'Meadows roads Started 1988, finished Oct. 1993 06-01 Exeter IIigh Street, downtown area Started and finished 1990 Exeter Glenerin Ln. Started spring 1991, finished fall 1992 Exeter Prentice Way Started 1985. sporadic until done in 1991 Exeter Henderson Swasey Forest road Built 1993-logging road 06-03 Exeter Oaklands Forest road Built December 1993-logging road 06-03 Newfields Logging Areas Within the Watershed Town Forest Narne/Owner Map Exeter Henderson-Swasey/town owned 06-03 Exeter Oaklands/town owned 06-03 Exeter Privately owned 06-03 Farms Within the Watershed Town Farm Type/Owner Map/RPC Farm Stratharn Stuart Cow Farm/John Men-ill Map 3 Stratharn it-tersweet Dairy Farm/Doug Scammen Map I Stratharn T'al, -frlit "C 2 Stratharn Veggies "C 3 Stratham Veggies "C 5 Stratharn Small fruit RPC 7 Stratharn Equestrian "C 9 Exeter Greenhouse/Nursery "C 6 Exeter Greenhouse/Nursery "C 12 Newfields Tree farm/small fnjit/ Hayden IMC I/Map 201 Newfields Corn/Hayden Map 201 Newfields Grains and veggies/Goldsmith Map 203 Newfields Grains and veggies/rinn Map 204 29 Town Storage location Stratham Leave in pfles where removed Exeter Next to lagoons at WWTP Newfields No snow removal Salt storage sit Stratham Public works, Bunker IEII Ave Exeter Public WOTks at WWI?-covcred Newfields Next to WWTP-Haxvey Rd. -covered State Route 108 in Newfields-covcred Salt /sand appil ations Town Roads affected Rate of application Stratham All roads in watershed except Squamscort 200 tons salt:264 tons sand for 94 and 95 and RtIOI/108 333 tons salt:200 tons sand for 88-93 Exeter All roads except Newfields Rd and Rt 101 4000 tons salt/yr, 8 tons sand:1 ton salt 88-94 Newfields All roads except Rt 85 State maintained Strathmn Squamscott Rd and Rt 101/108 12.8 tons salt /lane mile for 95 24.2 tons saft/lane mile 88-94 24 yds. sand:6 yds salt ( I yd3 sand=2 tons) Exeter Newfields Rd/Rt 101 same as above Newfields Route 85 (Newfields Rd) sameas above Contaminated sites Town Site Name Site a-d-dress'T. own maptlot Description/RPC Reference Stratham LabWs Beauty Salon 255 Portsmouth Ave, MapI 4/1 -1 Underground Injection Control QJIC)11 Strathain Stratharn Condos Route 108, Map 3/11 Malfunctioning septic system/5 Stratharn Stratham Ifighway Garage Bunker lhll Ave., Map 1/19 Leaking underground storage tank (LUST)/6 Strathafn Gil's Jeep Eagle Peugeot 50 Portsmouth Ave., Map 9/20 Non-hazardous holdinp tank permit17 Stratharn Sulfivan Tire 33 Portsmouth Road, Map 9/1 Non-hazardous holding tank/8 Stratham Saef Uncoln Mercury/Goss Portsmouth Ave, Map 7/12 LUST/9 I - Stratharn Antique Repair Company 23 Portsmouth Ave, Map 1/6 Hazardous waste/10 Stratharn King's Itighway Plaza Portsmouth Ave, Map 7/13 LUST/I I Stratham Labonte Sunoco Portsmouth Ave, Map 1/5-2 LUST/12 Stratham Charter Gas Station IPonsmouth Ave, Map 7/7 ILUST/14 I IfIxeter Brockhouse'Corp. lEpping Rd, Map 5-4/18-24 JUIC/13 30 Exeter Dreher-liolloway 156 Epping Rd, _ap 5-4/14 LUST/I 5 1 Exeter Adams Russefl Inc Lot 1 Exeter Ind. Park, Map 05-04/018.028 Hazardous waste/16 Exeter Exeter Ind. Park Industrial Park Rd, Map 05-041/19.1,19.3 Hazardous waste/17 Exeter Texaco Service Station 84 Portsmouth Ave, Map 9-2/6 LUST/21 Exeter Globe Shopping Ctr Portsmouth Ave, Map 09-OZ/1 0 LUST/22 Exeter Mobil 54 Portsmouth Ave, Map 09-01/9 LUST/23 Exeter Exeter Gas Works 277 Water St, Map 09-09/04-05 Oil spUl or release (1992)/25 Exeter Petrol storage 42 Portsmouth Ave, Map 9,10/7-14 Hazardous waste/26 Exeter Exeter Hospital 10 BuzeH Ave, Map 9-11/2 LUST/27 Newfields Strathwn Veterinary Clinic Route 108, Map 201/24 UIC/2 Newfields Newfields Country Stom 66 Main StrePA, Map 102/16 LUST/4 31 F t c e BM 7\1 N\ GI)If Cou 17, SR 1 /1.2 s 1.6 SM M I, `49 \ I - - @ , . Rockiniham M- 63@ 1.4 1.5 Clark /X I - ewfiefds ar@ 11@ I I c e MIJ-- .......... 0 CHIN M 5 SR 24- $ z .?',0 r a!e C B-7 n Itration M3 r1a New iel 4 5 SK3 d J 0 41 4 V 6 22.- a T 0-o-k CBS Greenwood a M 22 Cern, SR 7 X n. /-z % *Stratharn@ I@fS /GB 9' sR 8 c e,- 7= SR 21 --.IA49 /GB 10 trat1fa-mi '3 100-- SR 9r vo Mn. -SR 20 e M 20 Sch 00 vi -80 SR 10 SR I' /GH S c@ M 19 Graved Pitsi Oxbow jZ0,1 0, Cut Figure 1. Sampling sites in the northern portion of the, stud area. y 9 /V NW GB IZ SR 17 Fort Rock, . ......... .. ..... ... . ...... .... M 16 \.GB 13 SR 16 .,A C Po ells z N, AD V- P01,11t -49 e e Tra'ier' Ir 'zz -4. t 0 C, 1P (11 )0 Z'ater SR 25 /M25 PO W derhou s A- (6 Q/ yr, t 0 V . . ....... 17 /SR 14 'Ejz X . "\X Lax U.. 4v,) WAY 0 ER 2'--" Aq 0 V 0 't hillips hxe T --X cade Cemetery' -0 ER1 -@7 T'U M P i ta`@-- zle, ER J-. 0 ER3 C. c z -n 14-EXT- .ch Cji:@-', 0 "7 i FL Tail c2 Z) Pa ER 6 '0 av q 7P ER 5 ER 4 Y( wqad Judes Patniv Pond C 0.1 7 x 37. 0 ko 0 A L S3 C E Sh N 1-%, . , 'I'- - .. i, 1 4 \n GB 1: vma Figure 2. Sampling sites in the southern portion of the study area. 33 Figure 3. Geometric mean bacterial indicator levels in the Squamscott River going upstream from Chapmans Landing to the Exeter POTW: 1994-95. 250 0 Fecal coliforms 200 R E. coli Enterococci 150 C. perfringens 50 0 GB 7 GB8 GB9 GB10 GBI1 GB12 GB13 Site L 34 Figure 4. Mean amonium, nitrate and orthophosphate concentrations in the Squamscott River going upstream from Chapmans Landing to the Exeter POTW: 1994-1995 40.00 -- Mean NH4 35-00 El Mean N03 30.00 Mean P04 =L C .0 25.00 C 20.00 0 15.00 M 10.00 5.00 0.00 GB 7 GB8 GB9 GBI 0 GB1 1 GB12 GB13 35 Figure 5A. Effect of tide stage on geometric mean bacterial indicator levels from monthly sampling at Chapmans Landing (GB7) in 1994. 70 60 Low tide 50 High tide 40 30 20 10 0 Fecal coliforms E. coli Enterococci C. perhingens Indicator 36 Figure 5B. Fecal coliform concentrations in the Squamscott River going upstream from Chapmans Landing to the Exeter POTW along a salinity gradient on 10/25/94. 800 700 600 500 400 300 200 100 0 0 2 4 6 8 10 12 14 Salinity (ppt) 37 Figure 5C. Fecal coliform concentrations at tributary mouths in the Squamscott River going upstream from Chapmans Landing to below the Exeter POTW along a salinity gradient on 4/28/95. 90 80 70 60 50 40 30 20 10 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Salinity (ppt) 38 Figure 6. Geometric mean bacterial indicator levels in Exeter River tributaries going upstream from the dam: 1994-95. 120 100 Fecal colifonns E. coli 80 Enterococci C. perfringens 60 40 20 L, Li i 0 1 9-EXT ER-1 ER-2 ER-2' ER-3 ER-4 ER-5 ER-6 ER-7 14-EXT Site 39 Figure 7. Mean ammonium and nitrate concentrations in Exeter kiver tributaries going upstream from the dam: 1994-95 12.00 mean NH4 10.00 ElMean N03 8.00 0 6.60 4.00 2.00 0.00 9-EXT* ER-1 ER-2 ER-3 ER-4 ER-5 ER-6 ER-7 14-EXT* 40 Figure 8. Mean orthophosphate concentrations in Exeter River tributaries going upstream from the dam: 1994-95 0.35 0.3 0.25 =L C 0 0.2 C C 0 0 0.15 C M 0.1 0.05 0 9-EXT* ER-1 ER-2 ER-3 ER-4 ER-5 ER-6 ER-7 14-EXT* 41 Figure 9. Geometric mean bacterial indicator levels in Squamscott River tributaries going clockwise from Newmarket to Exeter and back: 1994-95. 1000 900 800 Fecal coliforms E. coli 700 Enterococci 600 C. perfringens 500 U 400 300 200 100 0 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 GB 7 Site 42 Figure 10. Mean concentration of NH4 in Squamscott River trib'utaries going clockwise from Newmarket to Exeter and back: 1994- 95 45.00 40.00 35.00 r 30.00 25.00 C C 0 20.00 0- C 15.00 10.00 5.00 0.00 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 GB 7 43 Figure 11. Mean concentration of N03 in Squamscott River tributaries going clockwise from Newmarket to Exeter and back: 1994- 95 225.00 200.00 175.00 =L 150.00 C 0 125.00 C 0 100.00 C 75.00 50.00 25.00 0.00 owl 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 CB 7 44 Figure12. Mean concentration of P04 in Squamscott River tributaries going clockwise from Newmarket to Exeter and back: 1994-95 1.80 1.60 1.40 1.20 C .2 IT 1.00 4- C C 0 0 0.80 C CU 0. 60 0.40 0.20 J- J 0.00 1 3 4 5 6 9 10 11 14 19 20 21 22 24 25 GB 7 45 Figure 13. Bacterial indicator levels in Squamscott, River tributaries going clockwise from Newmarket to Exeter and back on 6/7/95. 7000 60W Fecal coliforms E. coli 5000 Enterococci 4000 U 3000 2000 1000 0 --4 en tn @O ON 't 0% 0 C14 W) r- N N C4 Cq C4 Site 46 Figure 14. Geometric mean bacterial indicator levels in the Squamscott River at tributary mouths going upstream from Newmarket to Exeter:. 1994-95. 400 350 Fecal coliforms 300 E. coli Enterococci 250 C. perfringens 200 150 100 50 0 q* C4 00 C4 Site 47 Figure 15. Nutrient concentrations in the Squamscott River at tributary mouths going upstream from Newmarket to Exeter 20.00 18.00 NH4 16.00 El N03 P04 14.00 12.00 0 10.00 0 8.00 - 6.00 - 4.00 - 2.00 0.00 Mi M5 M4 M3 M24 M22 M8 M9 M21 M20 M10 M19 48 Figure 16. Fecal coliforms and enterococci in tributaries and at their mouths going upstream along a transect of the Squarnscott River on 4/26 (tribs) and 4/28 (mouths), 1995. 160-- 140-- Tributary 120.- 1001 El mouth 80 60-- 40-- 20 0 1 5 3 22 9 20 Site 20 18 16 Tributary 14 E]Mouth 12 10 6 4-- 2 1 7 0 4- 1 5 3 22 9 20 Site 49 Figure 17. N03 concentrations in tributaries and their mouths in the Squamscott River on 4/26 (tribs) and 4/28 (mouths):'1995 250-00 200.00 Mouth Trib .2 150.00 w CD C.) C 0. C.) 100.00 CV) 0 z 50.00 0. 0 0 1 5 3 22 9. 20 50 Figure 18. NH4 concentrations in tributaries and their mouths in the Squamscott River on 4/26 (tribs) and 4/28 (mouths), 1995 20.00 18.00 16.00 Mouth El Trib 14.00 12.00 10.00 0 U 8.00 z 6.00 4.00 2.00 0.00 1 5 3 22 9 20 51 Figure 19. Fecal cofiforms and enterococci in tributaries and at their mouths going upstream along a transect of the Squamscott River on 6/7/95. 7000 6000 Tributary 5000 Mouth 4000 3000.- 2000.- 1000 0 1 5 3 22 9 21 20 19 25 Site 4000- 3500 1 3000 1 Tributary Mouth 2500 1 2000 1 1500 1 1000.. 500 0- 1 1 5 3 22 9 21 20 19 25 Site 52 Figure 20. Flow rates in freshwater tributaries to the Squamscott River on 6/16/95. 25000 20000 15000 10000 5000 0 1 5 6 24 22 9 21 20 lo 19 25 Site 53 Figure 21. Estimated loading rates, based on 6/16/95 flow rates and 6/7/95 data, for bacterial indicators in Squamscott River tributaries. 1400000 1200000 1000000 Fecal coliforms E. coli Enterococci 800000 U 600000 400000 200000 0 1 5 6 24 22 9 21 20 10 19 25 ,@A Site 54 Figure 22. Estimated loading rates, based on 6/16/95 flow rates and overall geometric mean data, for bacterial indicators in Squamscott River tributaries. 400000 350000 300000 Fecal coliforms El E. coli 250" Enterococci C. perftingens 200000 150000 100000 50WO 0 1 5 6 24 22 9 21 20 10 19 25 IL Site 55 300.00 250.00 200.00 150.00 100.00 50.00 0.00 L 1 5 6 9 10 19 20 21 22 24 25 N03 Loadinc 1200.00 1000.00 800.00 0 z 600.00 400.00 200.00 0.00 1 5 6 9 10 19 20 21 22 24 25 P04 Loadinc 12.00 10.00 8.00 0 IL 6.00 - 4.00 2.00 0.00 1 5 6 9 10 19 20 21 22 24 25 in Figure 23. Estimated loading rates, based on 6/16/95 flow rates and 6n195 data, for nutrients Squamscott River tributaries. 56 Figure 24. Geometric mean bacterial indicator levels in a small tributary going downstream to the Squamscott River in Newfields: 1994-95. 250 Fecal coliforms 200 F] E. coli Enterococci 150 C. perfringens 100 50 0 1.1 1.2 1.3 1.4 1.5 1.6 Site mom L L 57 -C- 07 7.00 - 6-00 T 5.00 4.00 3.00 CZ 2.00 a 2 1.00 0.00 1.1 1.2 1.3 1.4 1.5 1.6 Site Mean N03 250.0 200.0 150.0 100.0 50.0 0.0 1.1 1.2 1.3 1.4 1.5 1.6 Mean P04 1.400 1.200 1.000 U.OUU 0 0.600 Zj 0.400 0.200 0.000 1.1 1.2 1.3 1.4 1.5 1.6 Fica-ure 25. Mean nutrient concentrations in a small tributary going downstream to the Squamscott River in NI: ewfields: 1994-95. 58 Figure 26. Mean Total suspended solids in Squamscott River tributaries and Chapmans Landing (GB7) 50.00 45.00 40.00 35.00 -j 30.00 E 25.00 cn co 20.00 15.00 10.00 5.00 I A- 0.00 + C? V* cn a U) CL cc cc cc Cc cc V-- V- C@ C@ C@ C@ C@ m co co w U) co U) 1� CL dc 1� cc cc cr Cc cc (D U) U) CD 0) U) co U) U) 59 Figure 27. Mean total suspended solids at sites in the Exeter River and tributaries 20.00 15.00 CD E 10.00 cn U) 5.00 0.00 ER1 ER2 ER3 ER4 ER5 ER6 ER7 EXT9 ER1 4 60 Figure 28. Mean total suspended solids at sites from Chapmans Landing (GB 7) to just above the Exeter POTW (GB 13) 20.00 - 18.00 - 16.00 14.00 -J 12.00 CD E 10.00 (n U) 8.00 6.00 4.00 2.00 0.00 T.- GB7 GB8 GB9 GB1 0 GB1 1 GBI 2 GB13 61 Figure 29. TSS (mg/L) at the mouths of tributaries to the Squamscott River 150.00 120.00 90.00 -j tM E cn cn 6 0. 00 30.00 0.00 CM C\j C\j CM U) (n U) Cf) cc cc CC cc cc cc CD U) C/) CD U) U) 62 Figure 30. Mean total suspended solids in a small tributary going downstream to the Squamscott River 45.00 40.00 35.00 30.00 25.00 E (n U) 20.00 15.00 10.00 5.00 0.00 SRI-1 SRI -2 SRI -3 SRI -4 SRI -5 SRI -6 63 y T ftM- q- ell? Figure 31. Location of farms and other potential sources of contamination in the Squamscott River watershed. 64 N F' S F o I I u t i o n f r o m A g r c u I t u r a I S o u r c e s 1 9 9 1 /17 1C, S tr e am s ::7j NN A gr i c u I t u r a L an d a n el P oa r y a i n e d S a i I s 1z 4 a -71 TV _5 5 c ci e Figure 32. Location of agricultural lands on poorly drained soils in Strathain: 1991. 65 Figure 33. New construction in resiJential areas within the Squarnscott River In watershed: 1990-94. 114 118 N e w f I e d S 122 87 1 0 - -60 ath 41 .9 eto (bit Bk 3 AR 121@ 127 C) 0i 131 124 d-. NR 0'. 128 MH ISM N11 134 0i qO C I Y\ Legend 66 Zone boundary Primary Roads N P S P o I I u t o n f r o ni S e p t i c S s t e rn s 1 9 8 6 @,A S t i- e a ni s A j R e s i d e n t i a I a r e a s o n ow o i- v ery 0 W s ep t i c s o s L t k J 14- J-' Aj Figure 34. Residential areas on soils with low or very low potential for septic systems in the Squamscott River watershed: 1986. 67 N P S P o I I u t i o n f r o ni S e p t i c S s t e rn s 1 9 9 1 I.--- EE 11 F ?y Streams R a s i d e n t i a I a r e a s a n I ow or JU V e r y I a w 411;1 3 e P t i Cs o s r7- V( Y-7 ............ Figure 35. Residential areas on soils with low or very low potential for septic systems in the Squamscott River watershed: 1991. 1-10 P o I e n t i o IC o n I a m i n a t i o nS i I e s---- "-, 1@11 11@1 I\.OIC qj.@@ -1 '5 VYI 04. T @C-. -%- 4 C @ r" ) @q J\ (,\ %V; @' %M "'A a t7"W'Iu. A MOPCI j 0 NJ 16 ur'L'6 19 IXI . (1"".V"(( @7'@J)n.fea- f '@ N@' Chop- A'CIQI NI /V 20 2 4"2 627 "N Figure 36. Locations of potential sources of other types of contaminants in the Squarnscott River watershed. Figure 37. Annual averages of monthly total suspended solids at Chapmans Landing in the Squamscott River: 1989-1994. 45 40 High tide 35 El Low tide 30 25 E CA rA 20 15 10 5 0 1989 1990 1991 1992 1993 1994 70 R a d w a y s a n d H d r o g r a p h y 1 9 9 1 Streams R o a d s Oft 528-19 Figure 38. Roadways and hydrography in the Squamscott River watershed: 1991. 71 Figure 39. Building permits within the Squarnscott River watershed: 1990-94. 40- Stratham BP Exeter BP Newfields BP 30- 20- '01 0- 1990 1991 1992 1993 1994 Year 72 -3 6668 14109 2421