Soil Health and Water Quality at St. Andrew s School, Delaware. Final Project Report. Submitted to: GreenWatch Institute, Inc.

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1 Soil Health and Water Quality at St. Andrew s School, Delaware Final Project Report Submitted to: GreenWatch Institute, Inc. Submitted by: Kyle Castillo, College of Engineering and Ms. Maria Pautler and Ms. Jennifer Volk, College of Agriculture and Natural Resources University of Delaware Colin Brownlee, Diana Burk, and Peter McLean St. Andrew s School Middletown, Delaware May 8, 2015

2 Table of Contents Acknowledgements.. 3 Project Background and Objectives..4 Background...4 Project Objectives.. 6 Project Methodology...7 Project Results..9 Project Summary and Conclusions.19 References..19 2

3 Acknowledgements This report summarizes the findings of an undergraduate research project conducted by Kyle Castillo, College of Engineering, at the University of Delaware (UD), under the supervision of Maria Pautler and Jennifer Volk from UD s College of Agriculture and Natural Resources (CANR). Funding for this project was provided by the GreenWatch Institute, Inc., St. Andrew s School, and UD CANR. The authors greatly appreciate the advice and assistance provided by Colin Brownlee, Diana Burk, and Peter McLean at St. Andrew s School. Additionally we would like to thank Marianne Hardesty at the USDA Natural Resources Conservation Service for sharing soil quality data and information about conservation practices employed on the St. Andrew s agricultural fields, as well as Andrew Homsey at UD s Water Resources Agency for providing the maps and land use chart contained within this report. We also appreciate the analytical support provided by the UD Soil Testing Program, which conducted analyses of water samples collected from Possum Creek and Noxontown Pond during the winter of Any questions or requests for information related to this report should be submitted to Maria Pautler at mpautler@udel.edu. 3

4 Project Background and Objectives Background: We have received funding from the GreenWatch Institute, Inc. for the past four years, which has enabled us to improve our understanding of the water quality of Noxontown Pond (which flows into the Appoquinimink River) and to develop specific monitoring techniques to improve our understanding of the inflows of pollutants, such as nutrients, into the Pond. Our most recent efforts, as detailed in this report, focused on monitoring stormflows into the pond and investigating the effects of best management practices on agricultural soil quality. A thorough background on the Noxontown Pond watershed, land use, water quality history, and stewardship efforts of St. Andrew s School can be reviewed in the prior project report prepared by Binder-Macleod et al., Figure 1. Noxontown Pond and surrounding area. 4

5 Figure 2. Possum Creek Watershed and approximate locations of sampling sites. Sample sites Figure 3. Land use of the Possum Creek Watershed. Land Cover in Possum Creek Watershed 4% 7% 19% 70% Developed Agriculture Forest Wetlands 5

6 Project Objectives: To build on past water quality monitoring efforts in Noxontown Pond and recommendations that were developed for best management practices on surrounding agricultural lands, we have this year begun looking at how those practices may impact soil health and ultimately water quality through more focused monitoring efforts along a tributary draining to Noxontown Pond, namely Possum Creek, which ultimately drains into the Appoquinimink River. Task 1: Soil Health One of the recommendations in the watershed management plan developed during a prior grant period was to improve the quality of the soil on St. Andrew s cropland through innovative farming techniques or improved cover crops for conventional farmers. This year, we planned to conduct soil quality measurements and further investigate BMPs to decide how to best improve soil quality on existing cropland. Over the course of the grant period, the project leads became aware of a recent soil health assessment conducted by staff from the USDA Natural Resources Conservation Service (NRCS) office. The Soil Health Tool (SHT), version 4.4, which integrates chemical and biological soil test information to quantify the quality of a soil, was used on the agricultural field directly to the west of, and draining to, Possum Creek. Rather than duplicating efforts, these data were provided for our assessment. Task 2: Continued Water Quality Monitoring Based on the findings from the previous report, we originally proposed for this year to continue to monitor the water quality of Noxontown Pond. St. Andrew s School staff relayed that they visually observed sediment entering the Pond from the tributaries during and after, rain events so it was decided to focus monitoring efforts on collecting stream samples during or immediately after these rain events. Based on further conversations with the St. Andrew s School staff, it was decided that we would target our storm monitoring along a transect of Possum Creek, a tributary to the Pond. Two locations both foot bridges over the creek were selected during a stream reconnaissance outing. The T-dock on Noxontown Pond itself was selected as the third downstream location; there is a history of data from this location as the T-dock has been monitored in prior years of this project. All sites were accessible by foot. 6

7 Project Methodology Task 1: Soil Health Since NRCS had recently conducted soil health testing, we relied on use of their data rather than duplicating efforts. (For more information about the Soil Health Tool, version 4.4, see the explanation provided by Dr. Rick Haney, USDA-ARS at The soil was assessed for its organic carbon and nitrogen composition with the Solvita 1-day CO 2 -C test and water extractable organic carbon (C) and nitrogen (N) tests, respectively. The organic C:N ratio was then determined. This information collectively helps to inform of the level of microbial activity in the soil, and soil fertility. A SHT calculation using these data was then done to determine the health of the soil, with a value ranging between zero and 30. The calculated value indicates the soil s current health and informs the land manager of what improvements could be made (the tool assists this decision making by providing cover crop planting recommendations). By tracking the number over time, one would expect the value to increase as the soil health improves with those management decisions. Task 2: Continued Water Quality Monitoring Due to changes in UD personnel, the water quality monitoring portion of the project got underway later than originally planned and the authors thank GreenWatch Institute, Inc. for the no-cost extension that was granted. The investigators focused on collecting one sample from each location during storm events from January March We aimed to collect stream samples from one precipitation event per week. A total of nine storms were sampled over this winter period, three events each month. Samples were collected in mid to late afternoon, which coincided with the undergraduate intern s availability around his class schedule. Storms that were sampled varied in size from all snow on 2/16/2015 to almost a one-inch rain event on 1/12/2015. On each occasion, samples were collected from downstream to upstream. Table 1. Storm sample collection dates and times at three locations along Possum Creek and Noxontown Pond during the winter of Date Upper Footbridge Lower Footbridge T-dock Precipitation Amount (inches) 1/12/2015 4:29 PM 3:59 PM 3:25 PM /18/2015 3:45 PM 3:15 PM 2:49 PM /24/2015 3:50 PM 3:15 PM 2:40 PM /3/2015 4:45 PM 4:23 PM 3:50 PM /16/2015 3:50 PM 3:20 PM 2:50 PM - frozen /23/2015 4:25 PM 4:00 PM 3:35 PM - frozen /7/2015 2:27 PM 1:56 PM 1:30 PM - frozen /13/2015 4:03 PM 3:40 PM 3:15 PM /22/2015 5:00 PM 4:36 PM 4:12 PM

8 In situ measurements of temperature, dissolved oxygen, and ph were made in the field during or immediately following each storm event. In addition, a one-liter sample was collected at each of the three locations for laboratory analysis after three initial rinses with Creek/Pond water. From the Creek locations, care was taken to not disturb the bottom sediments as the Creek was always too shallow to fully submerge the bottle. From the Pond location, when not frozen over, the sample was collected at approximately two feet (0.6 meter) below the water surface. To prevent biological growth during transport, the one-liter sample was kept on ice in a cooler and then stored in a refrigerator until laboratory measurements could be performed. Each sample was analyzed for dissolved ammonia nitrogen (ammonia-n) and nitrate nitrogen (nitrate-n), dissolved orthophosphate (ortho-p), total nitrogen (Total N), and total phosphorus (Total P) by the UD Soil Testing Program (UDSTP). Water samples analyzed by the UDSTP for dissolved ammonia-n, nitrate-n, and ortho-p were first filtered through 0.45-um filter paper and then analyzed colorimetrically. Total N and P were determined on unfiltered samples by persulfate digestion and colorimetry. Table 2. Water quality analyses conducted on samples collected from Possum Creek and the T- dock of Noxontown Pond during the winter of Parameters measured (units) Method Performed by In the field In the lab Temperature ( o C) Dissolved Oxygen (mg/l) ph Dissolved Ammonia-N (mg/l) Dissolved Nitrate-N (mg/l) Dissolved Orthophosphate (mg/l) Total Nitrogen (mg/l) Total Phosphorus (mg/l) Electric Probe (SAS) LaMotte Kit (SAS) Electric Probe (SAS) Colorimetric Colorimetric Colorimetric Digestion, Colorimetric Digestion, Colorimetric Castillo Castillo Castillo UDSTP UDSTP UDSTP UDSTP UDSTP Time Delay Analysis The first three sets of samples collected from 1/12/2015, 1/18/2015, and 1/24/2015 were placed in a refrigerator and were not filtered until 1/26/2015 for subsequent laboratory analyses due to lab work scheduling issues. To test the impacts of the extended sample holding times for the 1/12/2015 (14-days) and 1/18/2015 (8 days) events and the impacts on laboratory results, the investigators executed a time delay analysis using the 1/24/2015 sample set, which were originally filtered within 2 days of collection and considered adequate (although immediate filtering is ideal to minimize chemical conversions of nutrient species). Unfiltered portions of the samples from 1/24/2015 were kept in the refrigerator until 2/5/2015 (12 days later) when additional filtering was done to approximately simulate the 8- and 14-day holding times of the first two events. The time delayed filtered samples from 1/24/2015 were subjected to the same laboratory analyses as the original filtered set for a comparison of results. This analysis is intended to inform what level of scrutiny, if any, should be placed on the results from 1/12/2015 and 1/18/

9 Project Results Task 1: Soil Health The agricultural field assessed by NRCS received a rating of 3.3 from the SHT, version 4.4, indicating that there is definite room for improvement, as the scale ranges from zero to 30, where 30 represents a healthy soil. Based on this value, the NRCS also provided a suggested cover crop planting mix of 60% legume and 40% grass to help increase the soil health number. The farmer managing the field did not ultimately plant this particular field with a cover crop in the fall of 2014, but did employ a radish-wheat mixture on adjacent fields. Since the assessed field did not experience any managerial changes over the project period that one would anticipate having an effect on the soil health assessment value, the investigators did not repeat soil health analyses in the late winter/early spring as originally planned. This type of test is typically done annually or every few years to track changes in soil health due to management decisions. Since no management changes were implemented during our study period, there was no need to retest the field. Task 2: Continued Water Quality Monitoring Visual Observations Prior project water quality assessments of Noxontown Pond have focused on summer months when the effects of eutrophication are most evident as algal blooms and murky conditions. This phase of the project focused on the winter months and investigated a tributary corridor draining to the Pond rather than the Pond itself. The investigators observed that the Pond continued to have murky water throughout the sampling period, while the water draining from Possum Creek was at times clearer but sediment-laden conditions were frequently observed. Since at least some of the surrounding agricultural fields were without winter cover, and riparian vegetation was dormant, field erosion and sediment transport were able to occur since little to no filtering was provided on the fields, down gradient to the stream, and along the stream corridor. Table 3. Visual observations of water color and condition during sampling of Possum Creek and Noxontown Pond in the winter of Date Upper Footbridge Lower Footbridge T-dock 1/12/2015 Clear; Water appeared clearest at this site. Coldest of the three sites. Water slightly stiff and still; barely noticeable flow. 1/18/2015 Mud-brown; Stream appears as Lower Footbridge appeared. Clear; Water appeared mostly clear, though slightly murky/muddy. Flowing downstream at a pretty fast rate. Bits of ice observed flowing downstream in water. Muddied leaves littered throughout site. Mud-brown; Stream is flowing very strongly. It is about a foot and a half Greenish-clear; Most of pond is frozen over. Murky visibility at bestroughly 2 feet. Most acidic part of all three sites. Murky-green; Ice still covering most of pond. Appears much murkier 9

10 Stream not flowing as strongly or as deep as at the Lower Footbridge. Visibility is zero. Water is extremely polluted with sediment. Also, the coldest temperature of the three sites. 1/24/2015 Clear; Stream appeared identical to the LFB site. Water stream is extremely shallow/barely recognizable. Water is the clearest of the three sites, as well as the calmest. Water is the warmest temperature yet recorded. It also has the highest amount of DO measured to date. 2/3/2015 Brownish-clear; Stream is still shallow - but not as shallow as the Lower Footbridge site. Water appears to be the clearest yet observed for this site. A pool of black mudmuck lies just immediately upstream from the site, and has some sediment as a result flowing downstream. Regarding all three sites, today sees a significant lowering of measured DO at each site, when compared to previous dates. 2/16/2015 Murky-clear; Only site of the three that wasn't frozen over. All over stream, sticks and like debris were flowing downstream. Stream looks very dirty, and visibility is deeper when compared to last sampling - it is overflowing. Nearly overtakes footbridge. Water is extremely polluted with sediment, and visibility in water is zero. Most acidic of the three sites. Clear; Stream became extremely shallow to the point where the stream itself was barely recognizable - an extreme difference when compared to last week's sample. Water is most basic yet observed since sampling cycle began. Clear; Stream appears to be even shallower than last sampling period. Parts are frozen over, slight sedimentation seen in water. Frozen; Stream was completely frozen over. Ice needed to be broken with weight. Ice broken relatively easy, stream allowed to flow after breaking. Water temp was than last sampling. Some noticeable sediment/debris floating directly on the surface. Most basic of the three sites. Slightly murky; Patches of ice cover pond; water appears a little murky - more prominent than last sampling. Sedimentation is noticeable on the surface of the water. Greenish; Pond is entirely frozen over. Color appears a greenish hue probably due to the ice. Not much sedimentation was present in the water itself. Visibility in pond is actually fairly deep. Lowest measured DO at this site to date. Frozen; Pond is completely frozen over. Ice is thick enough to support at least 200 lbs. 10

11 slightly murky. 2/23/2015 Very murky-brown; Water appeared to be heavy with sediment. Water is very murky, and is flowing at a faster rate. Stream also appears to be a deeper level than previously observed. 3/7/2015 Blackish-brown; Water appeared a murky black color, and was heavy with sediment as the Lower- Footbridge appeared. Stream also appeared to be deeper than it is normally. Area is still completely snow covered 3/13/2015 Sandy-clear; Stream appears just as the Lower Footbridge appeared. Water is extremely shallow, and has some bits of sand and debris floating around in it. Water is warmest yet recorded among the three sites 3/22/2015 Clear; Stream appears as Lower Footbridge site appeared. Some debris is floating around. However, site appears to be the cleanest looking of the three sites. Water level appears to be a bit of a moderate level. Warmest temperature yet recorded. below freezing Murky-brown; Pieces of ice observed flowing downstream. Water appears to be heavy with sand/mud. Stream also appears to be a deeper level than previously observed. Clear-brown; Stream is flowing well and has some sedimentation in it. Entire area is covered in snow, and stream appears to flow very slowly. The site is also extremely shallow. Sandy-colored; The stream appears to be clear with bits of sand flowing downstream. The water level also appeared to be extremely shallow as in the past. Clear; Stream appears to be extremely shallow, with some sandy debris and leaves flowing downstream. Mud and sand around area. Appears to be rough, and leaking into stream, as it wasn't before. Frozen; Pond is still completely frozen over, and covered with snow. Still covered with thick enough ice to support at least a good amount of weight without breaking in. White-frozen; Pond is still entirely frozen over as it was for two weeks. This time, water appears a white color due to the snow covering on top of the ice. Murky-white; Site has finally melted ice. Water color appears to be a murky white color with bits of frozen ice floating. Roughly 1/3 of the site is still completely frozen over. Water temp is also the warmest it s ever been Clear-green; T-dock appears to be a clear brown color. No more ice or any sign of freezing. Water felt very warm and very minimal debris was present. 11

12 Table 4. Images from the Possum Creek and Noxontown Pond sites during the winter of Date Upper Footbridge Lower Footbridge T-dock 1/12/2015 1/18/2015 1/24/2015 2/3/2015 2/16/2015 2/23/2015 3/7/2015 3/13/2015 3/22/

13 Parameters Assessed and Comparison of Results to Water Quality Ecological Indicators and Drinking Water Standards Following the methods listed in Table 2, each sample was assessed for a number of constituents both in the field and through laboratory analyses. We were primarily interested in data related to nutrients (nitrogen and phosphorus) and dissolved oxygen, as these parameters have both human and ecological health implications. The USEPA has established a drinking water standard for nitrate-n of 10 mg/l. If concentrations exceed this value, caution should be taken consuming the water as negative health effects could occur in certain fractions of the population especially the young, old, and those with weakened immune systems. In addition, the Delaware Department of Natural Resources and Environmental Control has established concentration thresholds for freshwater streams to assess if that waterway is impaired by nutrients. The threshold value is 3.0 mg/l for Total N and mg/l for Total P. Additionally, there is a freshwater quality standard for dissolved oxygen of 5.5 mg/l daily average concentration where the instantaneous minimum shall not be less than 4.0 mg/l. Often, when nutrient concentrations exceed the threshold values, dissolved oxygen concentrations fall below their standards and characteristics of eutrophic conditions (algal blooms, fish kills, reduced biodiversity) are observed. The following sections describe and graphically depict the monitoring data from storm samples collected from Possum Creek and Noxontown Pond during the winter of Temperature Throughout the course of the monitoring period, water temperatures, corresponding with air temperatures, were at their coldest at the end of February and increased in March. The Upper Footbridge site, which was the shallowest, tended to be the warmest with respect to water temperature. Figure 4. Temperature measurements from three sampling locations taken in the winter of Water T ( o C) /12/2015 1/19/2015 T-Dock Lower Footbridge Upper Footbridge 1/26/2015 2/2/2015 2/9/2015 2/16/2015 2/23/2015 3/2/2015 3/9/2015 3/16/

14 ph The observed ph of the three sites was always very close to between 6 and 7 units and did not vary much throughout the monitoring period. No clear trends between location or date were apparent. Figure 5. ph measurements from three sampling locations taken in the winter of ph (ppm) T-Dock Lower Footbridge Upper Footbridge 0 1/12/2015 1/19/2015 1/26/2015 2/2/2015 2/9/2015 2/16/2015 2/23/2015 3/2/2015 3/9/2015 3/16/2015 Dissolved Oxygen The dissolved oxygen concentrations measured at the three monitoring locations were consistently high, between 10 and 18 parts per million (i.e., mg/l) and representative of typical concentrations during winter months. Since cold temperatures limited biological activity, there was no demand on dissolved oxygen and concentrations remained near saturation values. There also appeared to be no clear trend based on location. Figure 6. Dissolved oxygen at three sampling locations taken in the winter of DO (ppm) /12/2015 1/19/2015 1/26/2015 2/2/2015 2/9/2015 2/16/2015 2/23/2015 3/2/2015 T-Dock Lower Footbridge Upper Footbridge 3/9/2015 3/16/

15 Nitrogen The predominant nitrogen species present at all three monitoring locations was nitrate-n which made up most of the Total N concentrations. Ammonia-N concentrations were generally low, and on several occasions, were at or below the detection level of the instrumentation. There appeared to be no clear spatial or temporal trends for ammonia-n. The nitrate-n and Total N concentrations however, tended to be greatest furthest upstream along Possum Creek at the Upper Footbridge site and lowest at the T-dock site on Noxontown Pond. This likely reflects the influence of nitrate-rich groundwater and overland runoff to the tributary. The concentrations appear to decrease as the water flows downstream and empties into the pond. This could be the result of dilution with less nitrate-rich water from other tributaries and overland runoff and direct atmospheric deposition directly to the Pond itself. The lower levels observed at the T-dock could also reflect physical and biological processes occurring within the Pond. Prior data collected from the T-dock and documented by Binder-Macleod et al. in 2013 also showed this location to have the lowest nitrate concentrations from other Pond-collected samples. With respect to temporal trends, concentrations did not appear to vary much across the monitoring period, with the exception of a few anomalies. This was expected because again, the data were all from winter months when little biological activity was occurring in the stream and riparian corridors. On no occasion did the nitrate-n concentration exceed the federal drinking water standard of 10 mg/l (purple line). On all but one sampling date, the Total N concentrations at both the Upper and Lower Footbridge sites exceeded the 3.0 mg/l target threshold (blue line) indicating that nitrogen is likely a concern, and likely most evident during the growing season. 15

16 Figure 7. Dissolved ammonia-n (top), dissolved nitrate-n (center), and Total N (bottom) from three locations in the winter of NH4-N (mg/l) T-Dock Lower Footbridge Upper Footbridge 1/12/2015 1/19/2015 1/26/2015 2/2/2015 2/9/2015 2/16/2015 2/23/2015 3/2/2015 3/9/2015 3/16/ T-Dock Lower Footbridge Upper Footbridge NO3-N (mg/l) /12/2015 1/19/2015 1/26/2015 2/2/2015 2/9/2015 2/16/2015 2/23/2015 3/2/2015 TN (mg/l) 3/9/2015 3/16/ T-Dock Lower Footbridge Upper Footbridge 1/12/2015 1/19/2015 1/26/2015 2/2/2015 2/9/2015 2/16/2015 2/23/2015 3/2/2015 3/9/2015 3/16/

17 Phosphorus Phosphorus concentrations both total and dissolved were relatively low at the three monitoring locations over the sampling period. Often, levels were at or below the detection limit of the instrumentation. It appears that phosphorus is most present at the upstream location at the Upper Footbridge. Like nitrogen, phosphorus concentrations at the T-dock were also historically low (Binder-Macleod et al., 2013). Like the other parameters, it was difficult to discern any clear temporal relationship, likely because all samples were collected during winter months when temperature did not vary significantly to impact any biological activity. The Total P in the tributary samples did occasionally exceed the target threshold of 0.1 mg/l (dashed blue line) to 0.2 mg/l (solid blue line). Phosphorus is often attached to sediment particles and enters waterways during and after rain events through overland runoff. Figure 8. Dissolved ortho-p (top) and Total P (bottom) from three locations in the winter of PO4-P (mg/l) T-Dock Lower Footbridge Upper Footbridge - 1/12/2015 1/19/2015 1/26/2015 2/2/2015 2/9/2015 2/16/2015 2/23/2015 3/2/2015 3/9/2015 3/16/ T-Dock Lower Footbridge Upper Footbridge TP (mg/l) /12/2 1/19/2 1/26/2 2/2/2015 2/9/2015 2/16/2 2/23/2 3/2/2015 3/9/2015 3/16/2 17

18 Time Delay Analysis The time delay analysis was done to determine how much, if any, scrutiny should be placed on the results of data from the first two sampling events (1/12/2015 and 1/18/2015) since the samples were not filtered until 14 and 8 days, respectively, after collection. To test the impact of holding time on results, samples collected on 1/24/2015 were filtered first on 1/26/2015, 2 days post collection, and then again on 2/5/2015, 12 days post collection. The tables below show the results and the percent difference in results. Table 5. Ammonia-N concentrations (mg/l) of samples collected on 1/24/2015. Filtered after 2 days Filtered after 12 days % Difference T-dock % Lower Footbridge % Upper Footbridge % Table 6. Nitrate-N concentrations (mg/l) of samples collected on 1/24/2015. Filtered after 2 days Filtered after 12 days % Difference T-dock % Lower Footbridge % Upper Footbridge % Table 7. Total N concentrations (mg/l) of samples collected on 1/24/2015. Filtered after 2 days Filtered after 12 days % Difference T-dock % Lower Footbridge % Upper Footbridge % Table 8. Ortho-P concentrations (mg/l) of samples collected on 1/24/2015. Filtered after 2 days Filtered after 12 days % Difference T-dock % Lower Footbridge % Upper Footbridge % Table 9. Total P concentrations (mg/l) of samples collected on 1/24/2015. Filtered after 2 days Filtered after 12 days % Difference T-dock % Lower Footbridge % Upper Footbridge % Based on this analysis, it appears the dissolved constituents may have been impacted by microbial activity in the full sample between sample collection time and when the samples were ultimately filtered, despite the fact that the samples were refrigerated during the interim. The total concentrations, though, since samples were digested first, showed relatively little difference as a result of the filtration time delay. Thus, this analysis shows that a time delay before filtering can have negative influences on dissolved concentration data and a best practice is to filter as soon as possible after sampling. As a result, the ammonia-n, nitrate-n, and ortho-p data from 1/12/2015 and 1/18/2015 should be flagged and scrutinized in subsequent assessments. There is still good confidence in the Total N and Total P concentrations from those dates. 18

19 Project Summary and Conclusions During this last grant period, we collected storm event water samples at two locations along Possum Creek, a tributary to Noxontown Pond, and one location at the Pond, near the confluence of the Creek with the Pond. Possum Creek drains the northwest portion of the Noxontown Pond Watershed and is predominately agriculture in land use. Due to changes in UD personnel, the water quality work did not get underway until January and results only represent winter months. We also analyzed soil quality data from a field within the agricultural drainage to Possum Creek. Since the soil was rated low in soil health, monitoring is advised as recommendations are made to improve soil health so as to not impact water quality. If cover crops are planted in fields that drain to the Creek and/or Pond then further soil and water assessments can ascertain that what is being done is indeed an agricultural best management practice to preserve both soil and water quality. References Binder-Macleod, R., T. Sims, M. Schuller, D. Burk, and P. McLean Water Quality Monitoring Strategies for Noxontown Pond at St. Andrew s School, Delaware: Final Project Report. Submitted to GreenWatch Institute, Inc., February 4,