Final poster[1]
1
Background The Effect of Fertilization and Environmental Factors on Water Quality in the Upper Cove River Watershed Abstract The purpose of this study was to determine the effects of the fertilization of a golf course and other environmental factors on the surrounding aquatic ecosystem. Water samples were collected and tested using Vernier probes at 8 locations along the upper Cove River watershed in south central Connecticut for temperature, dissolved oxygen, dissolved nitrate (NO 3 - ), pH, and conductivity within one hour of solar noon. Time, location, and environmental factors were observed and considered. Results indicate that average nitrate levels are higher in the East Side Tributary flowing from the golf course than in the control West Side Tributary, supporting the hypothesis that fertilizer runoff from the golf course may raise dissolved nitrate concentration in the water. Average nitrate concentrations at the confluence of the two tributaries and the outlet of that confluence into the Maltby Lake are higher than at the spillway and spillway outlet locations further downstream, suggesting that nitrate is being removed from the water by riparian wetlands. Also, average dissolved oxygen concentrations were higher in the West Side Tributary than in the East Side Tributary, indicating better water quality in the West Side (control) tributary. While some parts of the watershed may be affected by the golf course, the overall water quality of the upper Cove River watershed is healthy. Dissolved nitrate levels appear natural and do not exceed 1 mg/L. pH falls within a healthy range for aquatic ecosystems. Dissolved oxygen concentrations were well above the minimum 3 mg/L necessary to sustain healthy aquatic life. Observations • Water temperature decreased over time, corresponding to decreasing air temperature further into winter • Dissolved oxygen concentration increased as temperature decreased, as expected due to the solubility properties of gases 8 • Dissolved oxygen concentration ranged between 6.3 mg/L and 10.2 mg/L, with natural variation 8 • Average dissolved oxygen concentration was higher in the control West Side Tributary (8.3 mg/L at WSTH, 8.4 mg/L at WSTL) than in the East Side Tributary (6.7 mg/L at ESTH, 7.5mg/L at ESTL) • pH ranged from 6.18 to 7.10, with most of the measurements being slightly acidic. • Pine needles soaked in distilled water tested low pH (5.89), affirming that evergreens lower the pH . pH measurements were lowest at the end of October, when deciduous leaves were falling in the water • The highest recorded nitrate concentration was 1 mg/L, and some measurements were as low as 0.2 mg/L • Average nitrate concentrations were slightly higher in the East Side Tributary (0.6 mg/L at ESTH, 0.6 mg/L at ESTL) than in the West Side Tributary (0.4 mg/L at WSTH, 0.4 mg/L at WSTL), indicating that the East Side Tributary may be affected by golf course activities 4,5 • Average nitrate concentrations were lower at the spillway location (0.5 mg/L) and at the spillway outlet location (0.4 mg/L) than at the confluence (0.6 mg/) and the confluence outlet sites (0.6 mg/L) and the East Side Tributary locations (both 0.6 mg/L) further upstream •Conductivity has a downward trend as time went on. The conductivity of the snow samples were very low (10.8 µS/cm on 1/1/2011 and 6.6 µS/cm on 2/12/2011) indicating that snow is relatively free of impurities. This data explains the downward trend of conductivity with time, as the melting of snow dilutes impurities in the water, resulting in lower conductivity later on during the winter • There are no clear trends in the average conductivity for the 8 locations. The pine needle test measured high in conductivity (305.7 µS/cm), suggesting that decomposing organic material adds impurities to the water 9 References 1. "What is a Watershed?." Watersheds. 17 Nov 2009. US EPA. 22 Jan 2011 <http://water.epa.gov/type/watersheds/whatis.cfm>. 2. Yu, Zizi. “Hydrology at the Confluence of the Cove River Proper and a 300m Tributary.” Amity High School. 22 Jan 2011 3. "Introduction." GLOBE Hydrology 2005. 22 Jan 2011 <http://www.globe.gov/tctg/hydro_chapintro.pdf? sectionId=145&lang=EN>. 4. Mulholland, Patrick J. “Stream denitrification across biomes and its response to anthropogenic nitrate loading.” Nature 452, 202-205 (13 March 2008) < http://www.nature.com/nature/journal/v452/n7184/abs/nature06686.html> 5. Biello, David. "Fertilizer Runoff Overwhelms Streams and Rivers--Creating Vast "Dead Zones"." Scientific American 14 Mar 2008. 22 Jan 2011 <http://www.scientificamerican.com/article.cfm? id=fertilizer-runoff-overwhelms-streams>. 6. "Drinking Water Contaminants." Drinking Water. 11 Jan 2011. US EPA. 22 Jan 2011 <http://water.epa.gov/drink/contaminants/index.cfm>. 7. Hill, A.R. “Nitrate removal in stream riparian zones.” Department of Geography, York University, 4700 Keele Street North York, Ontario, M3J 1P3, CANADA. <http://cat.inist.fr/? aModele=afficheN&cpsidt=3165525> 8. "Dissolved Oxygen in Lakes." lakeaccess.org. N.p., n.d. Web. 20 Jan. 2011. <http://www.lakeaccess.org/russ/oxygen.htm.> 9. " Electrical Conductivity: Measuring Salts in Water." lakeaccess.org. N.p., n.d. Web. 20 Jan. 2011. <http://www.lakeaccess.org/russ/conductivity.htm.> 10. Hayashi, Masaki. “Temperature-Electrical Conductivity Relation of Water for Environmental Monitoring and Geophysical Data Inversion.” Environmental Monitoring and Assessment Volume 96, Numbers 1-3, 119- 128. <http://www.springerlink.com/content/h1326p53gmwq2260/> 11. "Why is pH Important?" lakeaccess.org. N.p., n.d. Web. 20 Jan. 2011. <http://www.lakeaccess.org/russ/pH.htm.> 12. "Print A Solar Noon Calender." Solar Noon . Oct 2007. InternetWorks. 22 Jan 2011 <http://solar- noon.com/>. 13. Fields, Scott. "Global Nitrogen: Cycling Out of Control." Environmental Health Perspectives (July 2004): A556-A563. SIRS Discoverer. Web. 20 Jan. 2011. Future Directions Data of the water chemistry of the upper Cove River watershed will continue to be collected at regular intervals until fall/winter of 2011. It would be ideal to obtain fertilization schedules from the golf course and permission to test the ponds on the golf course to better analyze the effect of fertilization on the water quality. Also, it may be interesting to study the presence of macro-invertebrates in the water during the warmer seasons. Another potential study would focus on the northeastern section of the upper Cove River watershed, where the water quality is likely affected by suburban residential activities. Upper Cove River Watershed Data Methods 1. Visit the upper Cove River watershed every 2 weeks. 2. Record date and time and make notes about the weather/surroundings. 3. Take air temperature measurement. 4. Travel to a sampling site. Record any relevant observations at each sample site. Collect water in bucket Measurements Secure water sample 5. Fill a bucket with water from the sample site. 6. Immediately test for temperature and dissolved oxygen. For each test, keep the probe tip completely submerged until readings stabilize, and avoid any contact with the tips of the probes. After each test, rinse off the probe with distilled water and gently dry with Kimwipes. Secure each probe back into its storage bottle if applicable. 7. Secure a water sample at each site and store in properly labeled 50mL Falcon tube. 8. Upon return to home or laboratory, measure each water sample for pH, conductivity, and dissolved nitrate. Do not use the conductivity probe at the same time as the other probes, since the conductivity probe sends out an Problem Statement How do natural environmental factors and potential human activities on a golf course affect the water quality of the upper Cove River watershed throughout autumn and winter 2010 - 2011? IV: Location in watershed and the date throughout the sampling period. DV: Indicators of water quality – temperature, dissolved nitrate concentration, pH, dissolved oxygen concentration, conductivity Constant: Consistent sampling procedures, all data is collected within 1 hour of solar noon 3 Hypothesis: Nitrate concentration will be higher in the East Side Tributary than in the West Side Tributary, since the East Side Tributary is likely affected by golf course fertilization. 4,5 Also, nitrate concentrations will be lower further downstream, as combination of the East Side Tributary with the West Side Tributary and with the lake will dilute nitrate concentration, and riparian wetlands along the stream may have a denitrifying effect. 7 Approach Two tributaries combine at a confluence in the wooded area between the Yale Golf Course and the Maltby Lakes. The East Side Tributary flows from the ponds of the golf course and is likely affected by golf course activities. The West Side Tributary originates in a wooded area that is undisturbed by human activity. Water data was collected at two locations on each tributary. Data from the East Side Tributary was compared with data from the West Side Tributary (the control) to determine the possible effects of any golf course activities. Also, the streams along the upper Cove River watershed are bordered by riparian wetlands. Several sampling locations downstream from the confluence are implemented to study the effect of riparian wetlands on dissolved nitrate concentration. Data is collected with Vernier electronic probeware. pH 5 5.5 6 6.5 7 7.5 pH W STH ESTH W STL ESTL Confluence Conf.Outlet Spillway Spill.Outlet C onductivity 0 50 100 150 200 250 (µS/cm ) W STH ESTH W STL ESTL C onfluence C onf. O utlet Spillw ay Spill.O utlet D issolved O xygen 0 2 4 6 8 10 12 (m g/L) W STH ESTH W STL ESTL Confluence Conf.Outlet Spillway Spill.Outlet Temperature 0 2 4 6 8 10 12 14 16 18 20 (°C ) W STH ESTH W STL ESTL C onfluence Conf. O utlet Spillw ay Spill. O utlet AIR TEM PERATURE N itrate A verage 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 (m g/L) pH Average 6.55 6.60 6.65 6.70 6.75 6.80 6.85 pH The Cove River is a 7km river located in south central Connecticut, with its headwater tributaries in a wooded area to the north of the Maltby Lakes. The Cove River watershed includes a variety of lake, wetland, suburban, and urban topography. The Cove River travels southward and empties into Long Island Sound at Bradley Point Park in West Haven, CT. The hydrology of the upper Cove River watershed is interesting both at the local level and at the global level. Locally, it is important to understand how human activities and natural environmental factors affect the waterways. Furthermore, since Maltby Lakes in the upper Cove River watershed is a potable water reservoir (managed by South Central Connecticut Regional Water Authority), it is important that the overall water quality of the Cove River is monitored to ensure that it is clean. Water data at the upper Cove River watershed also contributes to the global understanding of the hydrosphere through the GLOBE Hydrology Program. 3 C onductivity A verage 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 (µS/cm ) Conclusions In conclusion, the water quality of the upper Cove River watershed is healthy. Possible effects of the golf course on dissolved nitrate concentrations in the water were observed. Overall water quality appeared to be better in the West Side Tributary. While nitrate concentrations in the East Side Tributary coming from the golf course were slightly higher than nitrate concentrations in the control West Side Tributary, the presence of the golf course does not negatively affect the water quality of the upper Cove River watershed. Measurements indicate that the water is healthy for the sustenance of aquatic life and for human consumption. Differences in nitrate concentration could also be attributed to environmental differences (i.e. soil, vegetation) between the two tributaries. Also, data suggests that dissolved nitrate is filtered out as it flows through riparian wetlands between the spillway and the spillway outlet, as well as between the confluence and the confluence outlet. Nitrate concentrations measured do not exceed 1 mg/L, well below the EPA Maximum Containment Level of 10 mg/L. 6 Dissolved nitrate levels in the upper Cove River watershed are similar to the concentrations of naturally occurring nitrate. 16 Measurements of pH indicate that the water is slightly acidic, with pH levels falling mostly within the normal range of 6.5 to 8.5 for natural water. 11 These measurements did not deviate from expectations, since the watershed is densely populated by evergreens that add to the acidity of the soil. Observations suggest that natural fallen tree litter impacts pH. 9 Dissolved oxygen measurements also indicate that the upper Cove River watershed is healthy. Dissolved oxygen concentration varied between 6.3 mg/L and 10.2 mg/L, well above the minimum 3 mg/L necessary to sustain aquatic life without excess stress. 3 One human activity that is of particular interest is the fertilization of a golf course at the northern end of the watershed. Nitrogen is a main component of fertilizers, and runoff from fertilizer can add excess nitrate into rivers and lakes as nonpoint source pollution. While nitrate is an important nutrient for aquatic life, 3 excess nitrate is problematic for bodies of water. One of the main concerns is eutrophication, which causes algal blooms and depletes the water of dissolved oxygen, leading to significant loss of aquatic life. 4,5 Another concern is the presence of nitrate in drinking water. High nitrate concentration in drinking water (EPA Maximum Contaminant Level 10mg/L) is harmful to health and potentially fatal for infants. 6 Since the Maltby Lakes is a backup potable water reservoir, monitoring of nitrate concentrations in the upper Cove River watershed is especially important. Nitrate is also added naturally to water through the decay of organic material. 16 Excess nitrate is removed from the water through denitrification in which bacteria in the water convert nitrate into nitrogen gas and releases it into the atmosphere. 4,5 Research suggests that riparian wetlands (soaked areas adjacent to streams) effectively aid the removal of nitrate from water. 7 A recent study focused on the water quality of the Cove River Historical Site near the mouth of the river. 2 However, a study on the water quality of the upper Cove River watershed had not been conducted. Water quality of the upper Cove River watershed was monitored from October, 2010 to February, 2011. Dissolved nitrate (NO 3 - ) concentration was the focus of this study. Other indicators of water quality were also measured—dissolved oxygen concentration, conductivity, and pH. Water temperature was also recorded with each sampling. N itrate 0 0.2 0.4 0.6 0.8 1 1.2 (m g/L) W STH ESTH W STL ESTL Confluence Conf.O utlet Spillway Spill.Outlet D issolved O xygen Average 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 (m g/L) Pine Needle Mixture Nitrate: 10.3 mg/L pH: 5.89 Conductivity: 305.7 µS/cm Snow Sample 1/1/2011 Nitrate: 0.2 mg/L pH: 7.10 Conductivity: 10.8 µS/cm Snow Sample 2/12/2011 Nitrate: 0.2 mg/L pH: 6.30 Conductivity: 6.6 µS/cm Limitations There are several limitations to this study. One factor that limits the conclusions is the equipment used. The Vernier probeware is easy to use and reliable. However, errors in carrying out the procedures may have affected the results. The readings of the pH probe took many minutes to stabilize, and it is possible that readings were written down before the pH measurements truly stabilized. Two separate sets of probes were used, and the nitrate probes were not cross calibrated for each test. Also, the dissolved nitrate probe required calibration with sodium nitrate standard solutions before each use. Care was taken to keep the standard solutions as pure as possible; however, dilution of the standard solutions may have occurred. Another limitation regarding the nitrate probe is that the measurements are only precise down to 0.1 mg/L. Since all of the nitrate concentrations recorded were at or below 1.0 mg/L, it is difficult to ascertain that differences in nitrate measurements were significant. To increase the reliability of the results, alternate methods of measuring nitrate, such as the cadmium reduction method, can be used. 18 Another limitation of this investigation is that fertilization schedules were not available from the Yale Golf Course. Without fertilization data, conclusions drawn concerning the effect of golf course activities on nitrate levels in the water are speculative. It can only be stated that fertilization is one possible factor, among others, that affects water nitrate levels. ESTH ESTL WSTH WSTL Confluenc e Conf. Outlet Spillway Spillway Outlet
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Transcript of Final poster[1]
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Background
The Effect of Fertilization and Environmental Factors on Water Quality in the Upper Cove River Watershed
AbstractThe purpose of this study was to determine the effects of the fertilization of a golf course and other environmental factors on the surrounding aquatic ecosystem. Water samples were collected and tested using Vernier probes at 8 locations along the upper Cove River watershed in south central Connecticut for temperature, dissolved oxygen, dissolved nitrate (NO3
-), pH, and conductivity within one hour of solar noon. Time, location, and environmental factors were observed and considered. Results indicate that average nitrate levels are higher in the East Side Tributary flowing from the golf course than in the control West Side Tributary, supporting the hypothesis that fertilizer runoff from the golf course may raise dissolved nitrate concentration in the water. Average nitrate concentrations at the confluence of the two tributaries and the outlet of that confluence into the Maltby Lake are higher than at the spillway and spillway outlet locations further downstream, suggesting that nitrate is being removed from the water by riparian wetlands. Also, average dissolved oxygen concentrations were higher in the West Side Tributary than in the East Side Tributary, indicating better water quality in the West Side (control) tributary. While some parts of the watershed may be affected by the golf course, the overall water quality of the upper Cove River watershed is healthy. Dissolved nitrate levels appear natural and do not exceed 1 mg/L. pH falls within a healthy range for aquatic ecosystems. Dissolved oxygen concentrations were well above the minimum 3 mg/L necessary to sustain healthy aquatic life.
Observations• Water temperature decreased over time, corresponding to decreasing air temperature further into winter• Dissolved oxygen concentration increased as temperature decreased, as expected due to the solubility properties
of gases 8
• Dissolved oxygen concentration ranged between 6.3 mg/L and 10.2 mg/L, with natural variation8 • Average dissolved oxygen concentration was higher in the control West Side Tributary (8.3 mg/L at WSTH, 8.4
mg/L at WSTL) than in the East Side Tributary (6.7 mg/L at ESTH, 7.5mg/L at ESTL)• pH ranged from 6.18 to 7.10, with most of the measurements being slightly acidic. • Pine needles soaked in distilled water tested low pH (5.89), affirming that evergreens lower the pH . pH
measurements were lowest at the end of October, when deciduous leaves were falling in the water • The highest recorded nitrate concentration was 1 mg/L, and some measurements were as low as 0.2 mg/L• Average nitrate concentrations were slightly higher in the East Side Tributary (0.6 mg/L at ESTH, 0.6 mg/L at
ESTL) than in the West Side Tributary (0.4 mg/L at WSTH, 0.4 mg/L at WSTL), indicating that the East Side
Tributary may be affected by golf course activities 4,5
• Average nitrate concentrations were lower at the spillway location (0.5 mg/L) and at the spillway outlet location
(0.4 mg/L) than at the confluence (0.6 mg/) and the confluence outlet sites (0.6 mg/L) and the East Side Tributary
locations (both 0.6 mg/L) further upstream •Conductivity has a downward trend as time went on. The
conductivity of the snow samples were very low (10.8 µS/cm on 1/1/2011 and 6.6 µS/cm on 2/12/2011) indicating
that snow is relatively free of impurities. This data explains the downward trend of conductivity with time, as the
melting of snow dilutes impurities in the water, resulting in lower conductivity later on during the winter• There are no clear trends in the average conductivity for the 8 locations. The pine needle test measured high in
conductivity (305.7 µS/cm), suggesting that decomposing organic material adds impurities to the water 9
References 1. "What is a Watershed?." Watersheds. 17 Nov 2009. US EPA. 22 Jan 2011 <http://water.epa.gov/type/watersheds/whatis.cfm>. 2. Yu, Zizi. “Hydrology at the Confluence of the Cove River Proper and a 300m Tributary.” Amity High School. 22 Jan 20113. "Introduction." GLOBE Hydrology 2005. 22 Jan 2011 <http://www.globe.gov/tctg/hydro_chapintro.pdf?sectionId=145&lang=EN>. 4. Mulholland, Patrick J. “Stream denitrification across biomes and its response to anthropogenic nitrate loading.” Nature 452, 202-205 (13 March 2008) <
http://www.nature.com/nature/journal/v452/n7184/abs/nature06686.html>5. Biello, David. "Fertilizer Runoff Overwhelms Streams and Rivers--Creating Vast "Dead Zones"." Scientific American 14 Mar 2008. 22 Jan 2011
<http://www.scientificamerican.com/article.cfm?id=fertilizer-runoff-overwhelms-streams>. 6. "Drinking Water Contaminants." Drinking Water. 11 Jan 2011. US EPA. 22 Jan 2011 <http://water.epa.gov/drink/contaminants/index.cfm>. 7. Hill, A.R. “Nitrate removal in stream riparian zones.” Department of Geography, York University, 4700 Keele Street North York, Ontario, M3J 1P3,
CANADA. <http://cat.inist.fr/?aModele=afficheN&cpsidt=3165525>8. "Dissolved Oxygen in Lakes." lakeaccess.org. N.p., n.d. Web. 20 Jan. 2011. <http://www.lakeaccess.org/russ/oxygen.htm.>9. " Electrical Conductivity: Measuring Salts in Water." lakeaccess.org. N.p., n.d. Web. 20 Jan. 2011. <http://www.lakeaccess.org/russ/conductivity.htm.>10. Hayashi, Masaki. “Temperature-Electrical Conductivity Relation of Water for Environmental Monitoring and Geophysical Data Inversion.” Environmental
Monitoring and Assessment Volume 96, Numbers 1-3, 119-128. <http://www.springerlink.com/content/h1326p53gmwq2260/>11. "Why is pH Important?" lakeaccess.org. N.p., n.d. Web. 20 Jan. 2011. <http://www.lakeaccess.org/russ/pH.htm.>12. "Print A Solar Noon Calender." Solar Noon . Oct 2007. InternetWorks. 22 Jan 2011 <http://solar-noon.com/>. 13. Fields, Scott. "Global Nitrogen: Cycling Out of Control." Environmental Health Perspectives (July 2004): A556-A563. SIRS Discoverer. Web. 20 Jan. 2011.14. Horton, Tom, and Heather Dewar. "NITROGEN'S DEADLY HARVEST: FEEDING THE WORLD,POISONING THE PLANET ." Baltimore Sun (Sept. 2000): 1A+.
SIRS Discoverer.Web. 20 Jan. 2011.15. Mitchell, John G. "OUR POLLUTED RUNOFF: Widespread As Rain and Deadly As Poison." National Geographic Feb. 1996: 106-125. SIRS Discoverer. Web.
20 Jan. 2011.16. Parliman, D.J., 2002, Analysis of nitrate concentration trends in 25 ground-water-quality management areas, Idaho, 1961-2001: U.S. Geological Survey
Water-Resources Investigation Report Report 02-4056, 60 p. 17. "What is Nonpoint Source Pollution?." Polluted Runoff. 15 April 2010. US EPA. 11 Jan 2011 <http://water.epa.gov/polwaste/nps/whatis.cfm>. 18. “5.7 Nitrates.” Monitoring & Assessment. 19 February 2010. US EPA. 11 Jan 2011 <http://water.epa.gov/type/rsl/monitoring/vms57.cfm>.19. *All pictures taken by the researchers
Future Directions
Data of the water chemistry of the upper Cove River watershed will continue to be collected at regular intervals until fall/winter of 2011. It would be ideal to obtain fertilization schedules from the golf course and permission to test the ponds on the golf course to better analyze the effect of fertilization on the water quality. Also, it may be interesting to study the presence of macro-invertebrates in the water during the warmer seasons. Another potential study would focus on the northeastern section of the upper Cove River watershed, where the water quality is likely affected by suburban residential activities.
Upper Cove River Watershed
Data
Methods1. Visit the upper Cove River watershed every 2 weeks.2. Record date and time and make notes about the weather/surroundings. 3. Take air temperature measurement.4. Travel to a sampling site. Record any relevant observations at each sample site.
Collect water in bucket Measurements Secure water sample
5. Fill a bucket with water from the sample site.6. Immediately test for temperature and dissolved oxygen. For each test, keep the probe tip
completely submerged until readings stabilize, and avoid any contact with the tips of the probes. After each test, rinse off the probe with distilled water and gently dry with Kimwipes. Secure each probe back into its storage bottle if applicable.
7. Secure a water sample at each site and store in properly labeled 50mL Falcon tube.
8. Upon return to home or laboratory, measure each water sample for pH, conductivity, and dissolved nitrate. Do not use the conductivity probe at the same time as the other probes,
since the conductivity probe sends out an electric signal that would skew other results.
Problem StatementHow do natural environmental factors and potential human activities on a golf course affect the water quality of the upper Cove River watershed throughout autumn and winter 2010 - 2011?IV: Location in watershed and the date throughout the sampling period.DV: Indicators of water quality – temperature, dissolved nitrate concentration, pH, dissolved oxygen concentration, conductivityConstant: Consistent sampling procedures, all data is collected within 1 hour of solar noon 3
Hypothesis: Nitrate concentration will be higher in the East Side Tributary than in the West Side Tributary, since the East Side Tributary is likely affected by golf course fertilization. 4,5 Also, nitrate concentrations will be lower further downstream, as combination of the East Side Tributary with the West Side Tributary and with the lake will dilute nitrate concentration, and riparian wetlands along the stream may have a denitrifying effect. 7
Approach Two tributaries combine at a confluence in the wooded area between the Yale Golf Course and the Maltby Lakes. The East Side Tributary flows from the ponds of the golf course and is likely affected by golf course activities. The West Side Tributary originates in a wooded area that is undisturbed by human activity. Water data was collected at two locations on each tributary. Data from the East Side Tributary was compared with data from the West Side Tributary (the control) to determine the possible effects of any golf course activities. Also, the streams along the upper Cove River watershed are bordered by riparian wetlands. Several sampling locations downstream from the confluence are implemented to study the effect of riparian wetlands on dissolved nitrate concentration. Data is collected with Vernier electronic probeware.
pH
5
5.5
6
6.5
7
7.5
pH
WSTH
ESTH
WSTL
ESTL
Confluence
Conf. Outlet
Spillway
Spill. Outlet
Conductivity
0
50
100
150
200
250
(µS
/cm
)
WSTH
ESTH
WSTL
ESTL
Confluence
Conf. Outlet
Spillway
Spill. Outlet
Dissolved Oxygen
0
2
4
6
8
10
12
(mg
/L)
WSTH
ESTH
WSTL
ESTL
Confluence
Conf. Outlet
Spillw ay
Spill. Outlet
Temperature
0
2
4
6
8
10
12
14
16
18
20
(°C
)
WSTH
ESTH
WSTL
ESTL
Confluence
Conf. Outlet
Spillway
Spill. Outlet
AIR TEMPERATURE
Nitrate Average
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
(mg
/L)
pH Average
6.55
6.60
6.65
6.70
6.75
6.80
6.85
pH
The Cove River is a 7km river located in south central Connecticut, with its headwater tributaries in a wooded area to the north of the Maltby Lakes. The Cove River watershed includes a variety of lake, wetland, suburban, and urban topography. The Cove River travels southward and empties into Long Island Sound at Bradley Point Park in West Haven, CT. The hydrology of the upper Cove River watershed is interesting both at the local level and at the global level. Locally, it is important to understand how human activities and natural environmental factors affect the waterways. Furthermore, since Maltby Lakes in the upper Cove River watershed is a potable water reservoir (managed by South Central Connecticut Regional Water Authority), it is important that the overall water quality of the Cove River is monitored to ensure that it is clean. Water data at the upper Cove River watershed also contributes to the global understanding of the hydrosphere through the GLOBE Hydrology Program. 3
Conductivity Average
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
180.0
(µS
/cm
)
Conclusions In conclusion, the water quality of the upper Cove River watershed is healthy. Possible effects of the golf course on dissolved nitrate concentrations in the water were observed. Overall water quality appeared to be better in the West Side Tributary. While nitrate concentrations in the East Side Tributary coming from the golf course were slightly higher than nitrate concentrations in the control West Side Tributary, the presence of the golf course does not negatively affect the water quality of the upper Cove River watershed. Measurements indicate that the water is healthy for the sustenance of aquatic life and for human consumption. Differences in nitrate concentration could also be attributed to environmental differences (i.e. soil, vegetation) between the two tributaries. Also, data suggests that dissolved nitrate is filtered out as it flows through riparian wetlands between the spillway and the spillway outlet, as well as between the confluence and the confluence outlet. Nitrate concentrations measured do not exceed 1 mg/L, well below the EPA Maximum Containment Level of 10 mg/L. 6 Dissolved nitrate levels in the upper Cove River watershed are similar to the concentrations of naturally occurring nitrate. 16 Measurements of pH indicate that the water is slightly acidic, with pH levels falling mostly within the normal range of 6.5 to 8.5 for natural water. 11
These measurements did not deviate from expectations, since the watershed is densely populated by evergreens that add to the acidity of the soil. Observations suggest that natural fallen tree litter impacts pH. 9 Dissolved oxygen measurements also indicate that the upper Cove River watershed is healthy. Dissolved oxygen concentration varied between 6.3 mg/L and 10.2 mg/L, well above the minimum 3 mg/L necessary to sustain aquatic life without excess stress. 3
One human activity that is of particular interest is the fertilization of a golf course at the northern end of the watershed. Nitrogen is a main component of fertilizers, and runoff from fertilizer can add excess nitrate into rivers and lakes as nonpoint source pollution. While nitrate is an important nutrient for aquatic life, 3
excess nitrate is problematic for bodies of water. One of the main concerns is eutrophication, which causes algal blooms and depletes the water of dissolved oxygen, leading to significant loss of aquatic life. 4,5 Another concern is the presence of nitrate in drinking water. High nitrate concentration in drinking water (EPA Maximum Contaminant Level 10mg/L) is harmful to health and potentially fatal for infants. 6 Since the Maltby Lakes is a backup potable water reservoir, monitoring of nitrate concentrations in the upper Cove River watershed is especially important. Nitrate is also added naturally to water through the decay of organic material. 16 Excess nitrate is removed from the water through denitrification in which bacteria in the water convert nitrate into nitrogen gas and releases it into the atmosphere. 4,5 Research suggests that riparian wetlands (soaked areas adjacent to streams) effectively aid the removal of nitrate from water. 7
A recent study focused on the water quality of the Cove River Historical Site near the mouth of the river. 2
However, a study on the water quality of the upper Cove River watershed had not been conducted. Water quality of the upper Cove River watershed was monitored from October, 2010 to February, 2011. Dissolved nitrate (NO3
-) concentration was the focus of this study. Other indicators of water quality were also measured—dissolved oxygen concentration, conductivity, and pH. Water temperature was also recorded with each sampling.
Nitrate
0
0.2
0.4
0.6
0.8
1
1.2
(mg
/L)
WSTH
ESTH
WSTL
ESTL
Confluence
Conf. Outlet
Spillw ay
Spill. Outlet
Dissolved Oxygen Average
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
(mg
/L)
Pine Needle Mixture
Nitrate: 10.3 mg/L
pH: 5.89
Conductivity: 305.7 µS/cm
Snow Sample 1/1/2011
Nitrate: 0.2 mg/L
pH: 7.10
Conductivity: 10.8 µS/cm
Snow Sample 2/12/2011
Nitrate: 0.2 mg/L
pH: 6.30
Conductivity: 6.6 µS/cm
Limitations There are several limitations to this study. One factor that limits the conclusions is the equipment used. The Vernier probeware is easy to use and reliable. However, errors in carrying out the procedures may have affected the results. The readings of the pH probe took many minutes to stabilize, and it is possible that readings were written down before the pH measurements truly stabilized. Two separate sets of probes were used, and the nitrate probes were not cross calibrated for each test. Also, the dissolved nitrate probe required calibration with sodium nitrate standard solutions before each use. Care was taken to keep the standard solutions as pure as possible; however, dilution of the standard solutions may have occurred. Another limitation regarding the nitrate probe is that the measurements are only precise down to 0.1 mg/L. Since all of the nitrate concentrations recorded were at or below 1.0 mg/L, it is difficult to ascertain that differences in nitrate measurements were significant. To increase the reliability of the results, alternate methods of measuring nitrate, such as the cadmium reduction method, can be used. 18 Another limitation of this investigation is that fertilization schedules were not available from the Yale Golf Course. Without fertilization data, conclusions drawn concerning the effect of golf course activities on nitrate levels in the water are speculative. It can only be stated that fertilization is one possible factor, among others, that affects water nitrate levels.
ESTH
ESTL
WSTH
WSTL
Confluence
Conf. Outlet
Spillway Spillway Outlet
