[From the U.S. Government Printing Office, www.gpo.gov]








                                                                         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.

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           1995
            995





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           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.






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                                              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







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       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)     1ï¿½    CL     dc     1ï¿½    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