EFFECTS OF EUTROPHIC STORMWATER PONDS ON CLEAR CREEK WATER QUALITY IN WHEAT RIDGE, COLORADO Lisa Eagle, Ethan Newman, Clif Burt, Andrew Keiswetter, & Isaiah Sleeger 12/7/2012 For: ENV4970 Dr. Janke Metropolitan State University of Denver Fall 2012 EFFECTS OF EUTROPHIC STORMWATER PONDS ON CLEAR CREEK WATER QUALITY IN WHEAT RIDGE, COLORADO Lisa Eagle, Ethan Newman, Clif Burt, Andrew Keiswetter, & Isaiah Sleeger Abstract Polluted stormwater runoff is one of the leading causes of decreased water quality to water bodies across the country. Nutrients such as nitrogen and phosphorus, normally found in stormwater runoff, can lead to degraded conditions within water bodies affected. Retention, or wet ponds, are commonly used in developed areas for a number of purposes including detainment and improvement of water quality through filtering of pollutants. These ponds hold stormwater indefinitely, releasing excess as needed into nearby receiving water bodies. Prospect Park in Wheat Ridge, Colorado contains four such ponds, two of which, Prospect Lake and Bass Lake, discharge directly into Clear Creek, a major watershed. Prospect Lake was observed to be experiencing eutrophic conditions, while Bass Lake was not. Data was collected upstream and downstream of the discharge points to determine if the ponds were creating water quality issues, and for comparison of the two water bodies. The type of data collected included levels of nitrates and phosphates, and aquatic invertebrates as they are an indicator of water quality. The data obtained was used in forming a conclusion of whether the wet ponds in Prospect Park are designed and maintained properly to ensure water quality of Clear Creek. Key words: Stormwater, Eutrophication, Nutrient Pollution, Retention ponds, Wet ponds, Water Quality, Aquatic Invertebrates Introduction Eutrophication is a very slow process involving the natural aging of lakes and ponds that begins with the addition of nutrients into the system which promote the growth of phytoplankton such as algae (The Open University, 2012). However, human activity such as agriculture, use of fertilizers, and changes in land surrounding aquatic environments speed up the growth of phytoplankton (USGS, 2011). Rivers, streams, and stormwater discharge are mostly responsible for the loading of nutrients to aquatic environments through point and non point sources. Point source pollution originates mainly from industrial sources and wastewater treatment plants. 1 Nonpoint source pollution mainly stems from urban and rural land uses, varying from lawns, golf courses, surface runoff, agricultural fields, and atmospheric deposition. (Mueller and Spahr, 2006). Nitrogen and phosphorus are two of the most important nutrients involved in the process of eutrophication. In freshwater environments such as lakes and ponds, phosphorus is most often the nutrient in the lowest concentration and thus usually limits the growth of phytoplankton (Schindler, 1977). In coastal marine environments nitrogen, being the nutrient in lowest concentration, normally limits the growth of phytoplankton (Howarth & Marino 2006). Although, recent studies have indicated this to be a generalization making it difficult to take steps in improving eutrophic environments because existing models may not provide correct insight into the true role of these nutrients in differing ecosystems (Elser 2007). Nitrogen is commonly found in aquatic environments as nitrate (NO3-) or ammonia (NH4+ or NH3). Human activity affecting the concentration of nitrogen in aquatic environments includes fertilizer runoff, animal waste, wastewater and septic system effluent, fossil fuel, and industrial discharge (Bernhard, 2012). Phosphorus is commonly found in aquatic environments as phosphate (PO4-3) (Lee, 1978). Human factors affecting the concentration of phosphorus in aquatic environments include detergents, fertilizer runoff, animal waste, wastewater and septic system effluent, development/paved surfaces, industrial discharge, phosphate mining, drinking water treatment, forest fires, and synthetic material (Khan & Ansari, 2005). Excess nutrients promote phytoplankton such as cyanobacteria and dinoflagellates which are responsible for surface scum, oxygen depletion, and resulting fish kills (Smith, Tilman, & 2 Nekola, 1999). Low dissolved oxygen concentrations can result from the decomposition of phytoplankton. As bacteria decompose phytoplankton, they take up dissolved oxygen which is essential to many organisms living in aquatic environments. Therefore a decrease in dissolved oxygen concentrations could affect the ecosystem as a whole (Rushforth, 2009). Also, changes in the abundance and species composition of phytoplankton can change the quality of food available to higher trophic level organisms (Zimmerman). Additionally, blooms of phytoplankton can reduce the amount of light available to organisms and plants beneath the surface layer through turbidity and light attenuation which is the decrease in light intensity as a result of absorption of energy and of scattering due to particles in the water. Submerged Aquatic Vegetation (SAV) can be very sensitive to changes in water clarity, and if affected by severe eutrophic conditions, may cause a change in species composition (SERC, 2005). Many state and federal agencies monitor surface and groundwater quality with the goal of preventing severe eutrophication. Dissolved oxygen, pH (Janke, 2012), nutrients (nitrates and phosphorus), and chlorophyll are just a few of the water quality parameters that are often monitored (Kenney, Reckhow, & Arhonditsis, 2007). Because nutrients can come from many sources, wide-ranging strategies through watershed management are required to control eutrophication. A range of watershed programs have generated success, but they cannot keep up due to the increasing number of lakes and rivers experiencing these conditions (Stednick & Hall). Stormwater is a broad term that refers to all water running off of the land’s surface after a rainfall or snowmelt event. Naturally it is a small part of the annual water balance, but as 3 development increases, impervious surfaces such as parking lots, roads, shopping centers, and residential areas contribute to less water soaking into the ground and increased water runoff along with pollutants that are carried from these surfaces (EPA, 2009). Starting in the late 1990s, the Environmental Protection Agency (EPA) began to enforce requirements for stormwater runoff containment and treatment through the Clean Water Act (CWA) where those responsible are to follow set construction, maintenance, and design conditions (EPA, 2009). Stormwater ponds (retention or wet ponds) and wetlands should be designed and constructed to contain and filter pollutants that flush off of the landscape. Without proper maintenance, nutrients such as nitrogen and phosphorus collect creating water quality issues such as algae blooms, low dissolved oxygen, high pH, impacts to aquatic habitat, and unpleasant odors. When these excess nutrients are discharged to a receiving water body, water quality issues can be created (EPA, 2009 February). Prospect Park in Wheat Ridge, Colorado contains four stormwater retention (wet) ponds. Tabor Lake and West Lake discharge directly into Prospect Lake and Bass Lake respectively, and Prospect Lake and Bass Lake discharge directly into Clear Creek. Prospect Lake was observed to be discharging large amounts of algae into Clear Creek in the fall of 2012. As stated, Bass Lake also discharges directly into Clear Creek, but appears to contain minimal amounts of algae. Clear Creek, which originates at the Continental Divide in the Rocky Mountains of Colorado, and extends to the South Platte River, is a body of water that provides municipal water for many communities along its course. All of these wet ponds appear to be sufficient for their holding capacities, but a question was raised as to whether they are being monitored, or had been designed sufficiently for filtering capabilities, per EPA and Clear Creek Watershed Foundation 4 standards (Clear Creek Watershed Foundation, 2007). Also, what are the effects of the observed discharge to Clear Creek water quality, specifically nutrient levels associated with eutrophication? These questions and others may be answered through upstream and downstream sampling of water quality parameters such as nitrates, phosphates, pH, and aquatic invertebrates within Clear Creek at either side of the points of discharge. A comparison between the two ponds may also help to draw conclusions about how Prospect Lake compares to Bass Lake, and what design implementations can be made to improve the efficiency of their filtering capabilities. Literature Review Storm water retention/wet ponds Storm water retention ponds, or wet ponds, are designed and constructed to contain and filter pollutants that flush off the landscape. Without proper maintenance, common nutrients such as nitrogen and phosphorus found in storm-water can cause problems such as eutrophication. Humans are often directly responsible as the sources of excess nutrients present in storm-water runoff. Anthropogenic sources such as wastewater treatment, agriculture, and urbanization all contribute to the problem. These and other natural sources such as erosion and precipitation contribute nutrients that are all eventually washed into the watershed system and end up in lakes, reservoirs, and ponds(Gelder et al 2003). These bodies of water can become the sources of water quality issues and then become problems for other connected downstream waters. Humans can also help the watershed ecosystem in a number of ways through remediation practices. Some examples of this include creating phosphorus sinks, aeration, dredging, introduction of aquatic plants, reduction of waterfowl, and diverting storm water inflows elsewhere. Most of these examples have both benefits and drawbacks, and are usually expensive 5 to do. Phosphorous sinks are used when eutrophication is caused by internal loading of the body of water. Essentially, ferric oxide is dumped into the water and it chemically binds to the phosphorous to create reduced version of phosphorus that doesn’t contribute to the eutrophic conditions anymore. Dredging is employed sometimes in problem areas where internal loading issues have become critical and waters become unable to support most life. It requires excavating the top layer of sediment from the bottom of the lake and it can be very expensive. Aeration is used to oxygenate the water and in turn, reduce the anoxic conditions that contribute to eutrophication problems. Introducing more aquatic fauna and plants is somewhat effective in certain cases. They use and absorb the nutrients in the water to sustain their own life and in turn filter out some of the excess nutrients that become problematic over time. Reductions in waterfowl, particularly loafing species such as Canadian Geese and Mallards can reduce nutrient loading as well. It both reduces the amount of grazing on the important aquatic plants, and reduces the amount of their excrement waste that ends up in the water and causes problems (EPA 2009). In all cases, it is beneficial to catch the problem before it becomes out of control and use the simple and more inexpensive remediation efforts to correct the problem quickly. Aquatic Invertebrates An interesting statement was made about sampling methods entailing that it is best to keep them quick. Over sampling that produces a large mass of material, becomes a waste of time to sift through, and does not help with the overall results. A technique used when there was an extensive amount sampled, was to put the container in the hot sun and cover one side. In the exposed side they placed the algae/moss, and on the other side, they kept it open and placed a shade cover over that half. It was found that in the hot sun the invertebrates quickly removed 6 themselves from the algae/moss and swam to the cooler, darker covered side, making them easy to separate and quantify (R Chadd 2010). Collecting in mid depths such as less than a meter is the ideal method. Collecting at depths great than a meter pose issues for collection and does not provide any improved results. Collecting at the end of summer and into mid fall is said to be the best for results both in species abundance and in maximum effects of stressors. At this time of year aquatic invertebrates are found both in adult and larval stages and have gone through their most active time of year allowing for maximum uptake of contaminates (Malmqvist 2002). To assess toxicology, substrate samples were taken back to the lab and dried out for examination. These samples were sealed and kept safe from atmospheric contamination. Once dried, the samples were run for various compounds. Once these compounds were identified, the samples were compared to those of other part of the river system. By doing so they were able to get an idea of where certain compounds were leaching into this aquatic system (Chau 2007). Acute toxicity of a troubled water system was assessed through the examination of fish and invertebrates in the lab. Specimens were collected along the troubled river and marked for each location. At the lab, each specimen was examined and screened for various toxins, particularly heavy metal pollution. Both fish and invertebrates take up these toxins in their environment. Through the examination and location markers, the team of scientists were able to pinpoint specific location of pollutions along the waterway. This study was a great example of how you can assess water quality through the examination of a water systems local fauna (Buckler, et el 2005). 7 Pharmaceutical pollution is a major concern to city water systems. Pharmaceuticals are difficult to test for and react with other molecules in the water to form different compounds, thus making it even more difficult. In a study done on several water ways along the east coast, aquatic invertebrates were collected and tested in the lab. The focus of the study was to see how aquatic invertebrate up took pharmaceutical pollution in their environment and how it affected them. Challenges with the study were that there are hundreds of pharmaceuticals that could be tested for, and once they react with water become other compounds, making it difficult to pinpoint. This study did indicate that through assessment of aquatic invertebrates, much can be deciphered about the quality of their water system (Williams, et el 2011). Objectives The main objective of this project is to determine how nearby storm-water retention ponds affect water quality of Clear Creek near Prospect Park in Wheat Ridge, CO. It is important to determine the sources of excess nutrients that cause harmful algal blooms in storm-water retention ponds that discharge into the creek. It would be most beneficial to get a snapshot of water quality in the creek before and after an algal bloom. Also, it will be helpful to assess the macro-invertebrate populations in the area as indicators of water quality. Further, was the eutrophication from the lakes and other surrounding ponds spreading into the Clear Creek basin? 8 Study Area The study area was within Clear Creek near Prospect Park in Wheat Ridge, CO. The outlets of two storm water retention lakes were chosen as sampling sites because of their proximity to the Creek, and because the outlets were discharging directly into the creek. These lakes are called Prospect Lake and Bass Lake. See provided maps for details. Figure 1 - Denver Metropolitan Area 9 Figure 2 - Study Area, including labelled discharge canals MATERIALS AND METHODS On September 28, 2012 and November 2, 2012, our group collected data on water quality and invertebrate life from Clear Creek in the Prospect Park area in Wheat Ridge, Colorado. Data collection was carried out by using the proper materials, ideal sampling locations, and with the utilization of optimal on and off-site sampling procedures. Water quality parameters that could not be collected on-site were determined as soon as possible off-site. Statistical Analysis was also conducted off-site. A snapshot of Clear Creek water quality up and downstream of 10 stormwater retention pond discharges is described herein as a result of our methods and use of available materials. Materials The following materials were necessary for us to properly collect data: Tagline Vernier meter Vernier probes Non-Vernier temperature probe Aquarium sampling kit Catch net Collection trays Sample Collection Churn Sample collection bottle Sample bottles Cooler Waders GPS Lamotte Water Test Kit YSI Meter The materials that were most vital to our study are shown in Figure 1 below: 11 USGS Water Sampling Supplies Vernier Meter and Probes YSI Meter LaMotte Water Analysis Kit Figure 3 - Water Sampling Equipment used Water Sampling Locations The sample locations, or cross-sections, were carefully chosen at points in which there was uniformity throughout the water column; mostly consistent depths; fewer riffles in the water-flow; no obstructions in the cross-section; and away from split channels. These locations are marked in Figure 2, and the criteria for choosing these locations are described below. 12 Figure 4 - Sampling Locations For collection on September 28, samples were collected approximately 200 ft downstream and 300 ft upstream of a discharge into the Creek from Prospect Lake. The Lake was highly eutrophic, and the sampling point downstream of the discharge was saturated with algae as a result. Samples were first collected downstream around latitude 39.77415, and longitude -105.12679. The downstream collection was at latitude 39.77419, longitude 105.12873. These locations are seen in Figure 2 as “Downstream 1” and “Upstream 1”. Photographs from the site locations are shown in Figure 3. 13 Downstream 1 Upstream 1 Figure 5 - Downstream and Upstream of Prospect Lake discharge into Clear Creek For collection on November 2, samples were collected further west because the water level in Prospect Lake was too low and there was no resultant discharge into Clear Creek (see Figure 5). We moved further west and identified a discharge into Clear Creek from Bass Lake. This discharge was clear, unlike the discharge noted earlier from Prospect Lake. Samples were first collected approximately 400 ft downstream and 100 ft upstream of the lake discharge. The sampling coordinates are approximately 39.77355,-105.13103 for the downstream location and 39.77386, -105.13298 for the upstream location. These locations are seen in Figure 2 as “Downstream 2” and “Upstream 2”. Photographs from the site locations are shown in Figure 4. 14 Downstream 2 Upstream 2 Figure 6 - Downstream and Upstream of Bass Lake discharge into Clear Creek 15 Figure 7 - Comparison of water levels at the Prospect Lake discharge between sampling dates Water Sampling and Invertebrate Identification Procedures On-Site For the water sample collections, a tagline was drawn across from bank to bank at each sampling location. Samples were then drawn into the sample collection bottle at 10 equally measured intervals along the tagline. While drawing these samples, care was taken to ensure that each interval was evenly sampled by descending and ascending the nozzle of the sample collection bottle. Once the sampling bottle was full, it was carried to a partner on the bank with clean gloves on, so they could dump it into the churn. After all sample water was collected in the churn, it was agitated with the plunger and allowed to fill the sample bottles. These 16 techniques are illustrated in Figure 6 below. Four sample bottles were collected per location and then immediately put on ice. Setting up the Tagline Collecting Water Samples Use of Vernier Meter and Sample Collection Churning Water Samples Contents of kick screen into collection tray Figure 8 - Sampling methods on-site 17 Meanwhile, the Vernier meter probes were placed into the water at each location to measure pH, temperature, conductivity, and dissolved oxygen. After two minutes of adjustment time, the data from the probes was recorded at 2 minute intervals for a total of 5 measurements. In addition, a kick screen was used at each location to draw out aquatic invertebrates, which were then placed into collection trays (Figure 6) and given an initial identification. Lastly, an aquarium water sampling kit was used to determine pH, as well as levels of nitrites, nitrates, ammonia/ammonium, copper, and calcium; by placing drops of water onto the testing strips. Water Sampling and Invertebrate Identification Procedures Off-Site Off-Site sampling procedures included the use of the Lamotte Water Test Kit, YSImultimeter, and aquatic invertebrate identification guides. The Lamotte Water Test Kit sample procedure was carried out by placing 10 mL of a sample into the colorimeter bottle and ran as a blank. After the blank, the samples were mixed with reagents and scanned again in the colorimeter, which then outputted our nitrate as nitrogen or phosphate levels. This test was run separately per indicator to test for phosphate and nitrite levels. The YSI meter was used to test for dissolved oxygen, conductivity, nitrate levels, and ammonia/ammonium levels. Sample water for each sampling location was placed into a clean beaker and the YSI probe was placed into it, and then allowed to settle for a few minutes. Data from the meter was recorded in 2 minute intervals for a total of 5 readings per sample. Finally, aquatic invertebrates were identified via comparison to identification charts. 18 Aquatic Invertebrate Sampling For sampling aquatic invertebrates, the process was simple and straight forward. We were not continuing research already completed, nor were we comparing our research to that of another study. For those reasons, we chose an inventory approach rather than a quantitative approach. Our inventory approach was to gather invertebrates without limiting the time we roughed up the substrate, or how long we kept our net in the water. Our primary goal was to see what species were present in general numbers, not what was present in each sample in exact numbers to compare to another study on the same area. We used a 6” x 12” fine mesh net purchased at an aquarium store. To observe the invertebrates we used a 4” x 8” rectangle flat bottomed Tupperware container. To sample, we chose shallow spots on decent flow and surface agitation. We sampled several times in three zones: downstream, point source, and upstream. The net was held perpendicular to the river bottom and roughed up the substrate up flow from the net for approximately one minute. We filled our container with about an inch of water. We then dipped the net into the container. Tweezers were used to remove any excess debris and algae that were obstructing view. The container was left to settle for a couple of minutes before viewing. Upon viewing we noted each species observed and made an approximate count of their numbers. Statistical Analysis Off-Site For those samples with multiple observations, statistical analysis was conducted with MiniTab statistical software. This analysis is to determine whether or not the tested parameters are statistically different downstream from upstream. The data is run through a two sample t-test because there are not enough observations to run a z-test for normal distrib 19 RESULTS Sampling Site 1 – Prospect Lake discharge into Clear Creek (9/28/2012) Downstream Results from sampling downstream of the Prospect Lake discharge into Clear Creek are listed in Tables 1 – 3 below, and are separated by sample testing methods (on-site, YSI meter readings, and Lamotte Water Testing kit). Table 1 - On-site Vernier meter readings downstream of Prospect Lake Time 1140 1145 1148 1150 1152 Average St. Dev. Temp (°C) 19.4 19.2 19.3 19.4 19.4 19.34 0.09 pH 10.2 11.3 11.05 10.82 10.45 10.76 0.44 DO Conductivity (mg/L) (uS/cm) 1.9 763 1.9 780 1.8 790 1.8 783 1.8 784 1.84 780.00 0.05 10.17 Table 2 - YSI meter readings from downstream of Prospect Lake Time 1215 1218 1220 1222 1224 Average St. Dev. Temp Pressure DO Conductivity (°C) (mmHg) (mg/L) (uS/cm) 17.9 627.7 5.21 693 17.9 627.9 4.84 694 18 627.9 4.8 695 18.1 627.9 4.71 697 18.2 627.9 4.63 700 18.02 627.86 4.84 695.80 0.13 0.09 0.22 2.77 20 NO3-N NO3(mg/L) (mg/L) 11.59 51.30 11.25 49.79 11.52 50.99 11.79 52.18 12.1 53.56 11.65 51.56 0.32 1.40 Table 3 - Lamotte water test results from downstream of Prospect Lake NO2-N (mg/L) NO2- (mg/L) PO43- (mg/L) 0.38 1.25 1.86 Upstream Results from sampling upstream of the Prospect Lake discharge into Clear Creek are listed in Tables 4 – 6 below. Table 4 - On-site Vernier meter readings upstream of Prospect Lake Time 1259 1301 1303 1305 1307 Average St. Dev. Temp (°C) 20.2 20.2 20.3 20.3 20.3 20.26 0.05 pH 3.1 3.7 3.4 3.47 3.31 3.40 0.22 DO Conductivity (mg/L) (uS/cm) 1.9 857 1.9 860 1.9 863 2.1 865 1.1 869 1.78 862.80 0.39 4.60 Table 5 - YSI meter readings from upstream of Prospect Lake Time 1205 1208 1210 1212 1214 Average St. Dev. Temp Pressure DO Conductivity NO3-N NO3(°C) (mmHg) (mg/L) (uS/cm) (mg/L) (mg/L) 6.5 663 3.73 16.51 16.2 5.85 668 3.9 17.26 16.4 6.01 674 4.86 21.51 16.6 627.9 5.95 679 6.15 27.22 16.7 627.9 5.8 682 6.87 30.41 16.48 627.90 6.02 673.20 5.10 22.58 0.22 0.00 0.28 7.79 1.38 6.10 21 Table 6 - Lamotte water test results from upstream of Prospect Lake NO2-N (mg/L) 0.48 NO2(mg/L) 1.58 PO43(mg/L) 2.05 Notice that the results from Ammonia/Ammonium testing with the YSI meter are not listed. These results are absent because the YSI meter consistently read “++++”, which indicates over-range. Therefore, the only results for ammonia/ammonium are found with the aquarium test strip results as indicated in Table 7 below. These test strips are intended to give the aquarium maintainer a general idea of nutrient concentrations, and are not very precise for scientific applications. The YSI meter may have been out of range, but it is also possible that it was not calibrated or configured properly. Also notice that the results for on-site pH and conductivity are significantly different from downstream to upstream. It has been noted by peers and instructors that these particular Vernier probes can be unreliable. For statistical analysis, the YSI meter readings for conductivity were used instead. Also, the results from the aquarium test strips in Table 7 appear to give a more realistic picture of the pH levels at Sample Site 1. These aquarium test strip results are used in the results summary for Sample Site 1. Alternative Water Quality Testing Results from testing the water quality with an aquarium water testing kit on-site are listed in Table 7 below. 22 Table 7 – On-site aquarium test kit results from Prospect Lake area Sample Site pH Location Up Stream 8.2 Point Source Down Stream >8.8 NH3/NH4+ (mg/L) 4 4 4 NO2NO3(mg/L) (mg/L) 1 20 1 20 1 20 Aquatic Invertebrate Testing Upon arrival and visual inspection of the river, we hypothesized that the aquatic invertebrate count would be low as well as the species diversity. We did a preliminary assessment of water quality using test kits from an aquarium store. Our results showed a surprisingly high level of ammonia, 4 ppm mg/l. This result furthered our assumption. Upon the first sample observed it was clear that a diverse group of aquatic invertebrate inhabited this river. Once species were identified, it was clear that the river was indeed a good habitat for aquatic invertebrate fauna. Sensitive invertebrates such as stoneflies and may flies were present in large numbers as indicated in Table 8. These indicator species were present in each sample taken in each of the three zones showing good consistency for their populations. Excessively high numbers of aquatic planaria were present as well. These results indicate that the river has abundant nutrients and food sources to support these populations and that water quality is void of harmful amounts of pollutants and other toxins. Results from the aquatic invertebrate counts upstream, downstream, and at the point of the Prospect Lake discharge into Clear Creek, are listed below in table 8. 23 Table 8 – Aquatic Invertebrate counts in Prospect Lake area Aquatic Invertebrates Stone fly nymph May fly nymph Caddis Fly Crane fly Crayfish Midge larva Scud Leach Unidentified minnow Planaria Upstream Point source Down Stream 42 36 32 14 7 12 12 8 9 0 0 1 1 0 0 7 12 6 13 15 11 1 1 0 3 1 0 56 43 61 Sampling Site 2 - Bass Lake discharge into Clear Creek (11/2/2012) Downstream Results from sampling downstream of the Bass Lake discharge into Clear Creek are listed in Tables 9 – 11 below, and are separated by sample testing methods. Table 9 - On-site Vernier meter readings downstream of Bass Lake Time 1404 1406 1408 1410 1412 Average St. Dev. Temp (°C) 17 17.1 17.1 17.1 17.2 17.10 0.07 24 pH 7.5 7.96 8.12 8.18 8.23 8.00 0.30 Table 10 - YSI meter readings from downstream of Bass Lake Time 1600 1602 1604 1606 1608 Average St. Dev. Temp Pressure DO Conductivity (°C) (mmHg) (mg/L) (uS/cm) 7.8 631.3 8.9 654 7.9 631.3 8.8 656 8 631.3 8.8 659 8.2 631.3 8.8 662 8.4 631.3 8.7 665 8.06 631.30 8.80 659.20 0.24 0.00 0.07 4.44 NO3-N (mg/L) 46.3 49.64 30.11 28.84 30.9 37.16 9.97 NO3(mg/L) 204.93 219.71 133.27 127.65 136.77 164.47 44.12 Table 11 - Lamotte water test results from downstream of Bass Lake NO2-N (mg/L) 0.36 NO2(mg/L) 1.18 PO43(mg/L) 2.15 Upstream Results from sampling upstream of the Bass Lake discharge into Clear Creek are listed in Tables 12 – 14 below. Table 12 - On-site Vernier meter readings upstream of Bass Lake Time 1442 1444 1446 1448 1450 Average St. Dev. Temp pH (°C) 17.7 7.91 17.7 8.11 17.7 8.17 17.7 8.23 17.7 8.24 17.70 8.13 0.00 0.13 25 Table 13 - YSI meter readings from upstream of Bass Lake (taken Time 1612 1614 1616 1618 1620 Average St. Dev. Temp Pressure (°C) (mmHg) 7.5 631.2 7.6 631.2 7.8 631.2 8 631.1 8.2 631.1 7.82 631.16 0.29 0.05 DO Conductivity (mg/L) (uS/cm) 8.1 650 7.8 651 7.7 656 7.7 659 7.7 664 7.80 656.00 0.17 5.79 NO3-N (mg/L) 21.43 20.37 19.85 21.03 23.98 21.33 1.60 NO3(mg/L) 94.85 90.16 87.86 93.08 106.14 94.42 7.08 Table 14 - Lamotte water test results from upstream of Bass Lake NO2-N (mg/L) 0.28 NO2(mg/L) 0.92 PO43(mg/L) 2.23 For Sample Site 2, fewer Vernier probes were used due to unreliability. However, the Vernier pH probe results did appear to be accurate this time. DISCUSSION Statistical Analysis The data collection results, with the exception of those that were taken from the Lamotte colorimeter, consisted of 5 observations for both upstream and downstream at both sample sites. Since there were less than 30 observations each, a two sample t-test was performed using the following hypothesis test and level of significance: 26 The t-value test statistic, p-value, and level of significance were collected for the pH, nitrate, and conductivity observations, and are shown in Table 15 below. Note that all parameters are statistically significant during the first sample collection, where highly eutrophic discharge was visibly evident. Table 15 - Statistical Analysis of Water Sample Results pH NO3Conductivity Sample Site 1 – Prospect Lake discharge tpsignificance value value Significant -33.25 0.000 Difference Significant -10.34 0.000 Difference Significant -6.11 0.004 Difference tvalue 1.01 Sample Site 2 – Bass Lake discharge psignificance value No Significant 0.371 Difference -3.51 0.025 Significant Difference -0.98 0.359 No Significant Difference Parameters noted in Table 15 for Sample Site 2 are not statistically significant with the exception of nitrates. However, had we chosen a level of significance of 0.02, we could then be 98% sure that there was no statistically significant difference between the true means of pH, nitrates, and conductivity at Sample Site 2 at the time of collection; with the opposite being true for Sample Site 1. Results Summary The results of sample testing downstream and upstream at both sites are summarized side-by-side in table 15 below. 27 Table 16 – Side-by-side results summary from both sites pH Conductivity (uS/cm) NO3- (mg/L) NO2- (mg/L) PO43- (mg/L) Sample Site 1 Sample Site 2 Upstream Downstream Upstream Downstream 8.2 > 8.8 8.13 8.0 673.2 695.8 656 659.2 22.58 1.58 2.05 51.56 1.25 1.86 94.42 0.92 2.23 164.47 1.18 2.15 The reported pH levels for Sample Site 1 are taken from the aquarium testing strip because the Vernier probe at the time was suspected of giving bad results. Regardless, the pH downstream would have certainly been higher downstream than upstream, because algae is known to increase pH levels (Bitton, 2011). Finally, nutrient levels from both sampling locations/dates are illustrated in Figure 7 below, shown with a base 10 logarithmic scale. Figure 9 - Graph of Sampling Site Nutrient Levels 28 Legal Compliance Despite our summary of information, it is important to note that at the time of initial sampling, the City of Wheat Ridge was in compliance with local and federal laws. The EPA’s National Pollutant Discharge Elimination System (NPDES) permits, part of the EPA’s Clean Water Act, do not require specific nutrient monitoring from point-source stormwater discharges (EPA, 2012). The Phase II Stormwater Rule created by the EPA in 1999, also does not contain such stipulations. These regulations generally include public education/outreach/involvement, detecting and eliminating illicit discharges, construction and post construction run-off control, and pollution prevention (City of Wheat Ridge, 2012). The purpose of these objectives is to reduce polluted runoff, but not necessarily to monitor nutrients from a point-source stormwater discharge into creeks. Cladophora It was determined that the algae being discharged from Prospect Lake is a filamentous type of algae that is part of the phylum Ulvophyceae. It often dominates periphyton communities and can produce nuisance growth problems during eutrophic conditions (AlgaeBase). The algae was identified by visual inspection and it was noted that it had rather large filaments and dichotomously branched makeup. Further microscopic investigation was required to identify the species type, but unfortunately the samples sat for too long and the algae decomposed in the sample bottle. Using the photographic evidence of the algal bloom, an educated guess would pinpoint the species as Cladophora glomerata. This species has mainly been causing problems in the Great Lakes region, but is widespread in many freshwater ecosystems including Colorado streams and reservoirs (Young et al 2012). Uncontrolled blooms are caused by excessive 29 nutrients (such as phosphorus) present within the water and the high nutrients are often attributed to anthropogenic sources such as urbanization, wastewater treatment, and agriculture. However, this species is attributed be more of a nuisance to humans rather than harmful to the ecosystem as a whole. There are even some beneficial aspects of the algae that include providing suitable habitat for aquatic invertebrates, uses in ecological engineering, and production of biofuels (Zulkifly et al 2012). Year round monitoring should be required in order to get a better understanding of the impacts the algae is having on downstream communities. Aquatic Invertebrates As discussed in the results section, aquatic invertebrate work as an indicator species for aquatic contaminates. Easily collected and observed, they make ideal specimens for research and quick assessment in the field. Prospect Park may not appear visually to have the water quality to support high levels of aquatic life but our sampling process proved otherwise. After assessing the results, this section of Clear Creek is a good habitat for supporting a large number of aquatic invertebrates and other aquatic life such as juvenile fish. More in depth studies would have to be performed to detail why we found such an abundance of planaria compared to other invertebrates and to pin point what nutrients and food are present that are supporting these large populations. Further studies that would help to assess water quality might entail taking the invertebrates back to a lab and assessing them for uptake of toxins. It is well studied that aquatic invertebrates intake toxins present in their environment (Buckler, et el 2005). 30 CONCLUSION The goal of our field study was to find out how much affect, if any, eutrophication of the wet pond Prospect Lake in Prospect Park had on Clear Creek water quality. Data collection for sample site 1 (Prospect Lake discharge) occurred on 9/28/12. After compiling data from this field study, we ventured out and collected a second sampling from a differing site, sample site 2 (Bass Lake discharge) on 11/2/12, and used this data to compare findings about the area. There were downstream and upstream samples for each point of discharge from Prospect Lake and Bass Lake. This was done to see whether there was a significant amount of nutrients such as nitrates and phosphorous, high pH, low levels of DO, and unhealthy temperature and conductivity levels downstream from the point of discharge which would indicate whether the eutrophication of Prospect Lake had an effect on water quality to Clear Creek. Bass Lake was used as a comparison as it was not showing signs of eutrophication. Aquatic invertebrate sampling was performed in the same manner as an indicator of water quality. Although eutrophication is a natural process, we were concerned with how much anthropogenic causes were contributing to this process in Prospect Lake. If the process is occurring too rapidly, and is not being monitored and treated, then it can have a direct impact to the habitat of the area and the water contained and flowing through it. In addition to taste and odor concerns associated with excess algae production, elevated levels of total organic carbon are an increasing concern because of the harmful and strictly regulated disinfection by-products that result from chlorinating water high in TOC. As observed, Prospect Lake is surrounded by concrete, an RV park, dog kennel, and a landscape that is treated with pesticides and fertilizers. It does not contain much of a natural wetland environment. Alternately, Bass Lake which is surrounded by a marshy area does not contain nearly as much algae, so it is more than likely 31 much better at filtering out pollutants and nutrients. Also, Bass Lake’s discharge is continually and slowly released which helps in the filtering process, while Prospect Lake is discharged a couple of times a year with large amounts at once. Taking this into account, Bass Lake could potentially be used as a reference in improving Prospect Lakes’ filtering capabilities. It can be concluded that although we received higher readings for nitrates from Bass Lake, this was most likely due to algae in Prospect Lake consuming the nutrient. Also, there were higher levels of phosphates downstream from both lakes, with Prospect Lake containing slightly less than Bass Lake. A possible reason for the unexpected higher amount of phosphates discharging from Bass Lake, considering its minimal amounts of algae, might correlate with the sampling of this site being conducted a few weeks later from the date of sampling of the first site. Furthermore, there had not been much precipitation and the temperatures were still considerably warm, so what was accumulated in the lakes had been sitting for a while without having been cycled. In addition we also found a significant amount of aquatic invertebrates in this portion of Clear Creek. This would imply that the water in the creek is not as polluted and toxic as we initially thought. In fact, it can be concluded that water conditions are good for supporting aquatic life. There appeared to be good food sources and plenty of nutrients for aquatic invertebrates to consume. Studies have shown that aquatic invertebrates from the top tear can handle a decent amount of pollution. After completing our study and evaluating the results, it can be concluded that the retentions ponds near clear creek need improvement of monitoring and design in order for them to perform better in naturally filtering out these nutrients. Further study of the area can help in 32 solidifying this conclusion. As with any study, there was room for improvement within our methods. Stricter and more precise lab methods for analysis and protocols for taking field samples could have been employed for better results, but this would have cost more money than we had available for our purposes. Also, the field equipment could have been better calibrated for greater accuracy in field tests. Additionally, year round sample gathering would present a better picture of cycling of nutrients through the system in the study area. The samples were gathered in the fall, when algal bloom does normally occur with “fall overturn”, but it also occurs, and normally to a greater degree, in the spring (Wright, 1993). Year round study could produce more enhanced and well rounded results. There were definitely way to improve our study, but with all things considered, we gathered sufficient enough data to obtain results and conclusions for this study. Interestingly enough, it seems we were not the only ones with an attitude toward monitoring nutrient levels discharged into the creek by stormwater ponds. The Colorado Department of Public Health and Environment introduced Regulation 85 effective September 30, 2012. This regulation affects localities with point-source stormwater discharges into streams, of which, Wheat Ridge has a permit to do so. As outlined in Regulation 85.6 (3)(c), the State’s Municipal Separate Storm Sewer System (MS4) permittees must submit a discharge assessment report by October 31, 2014. This report shall; “Allow for the determination of representative estimates that quantify MS4 discharge flows and associated concentrations, and loads of total nitrogen and total phosphorus from the permittee’s MS4. This shall include representative annual or seasonal information to define significant nutrient loads from different land uses due to rainfall events, snowmelt events, and/or dry weather flows.” (CO Dept. of Public Health & Env, 2012). Note that both total nitrogen and phosphorus concentrations will be part of this 33 monitoring objective, which is just what we set out to do with our project. It is good to know that the environmental consensus in our state is leaning in the right direction by going above and beyond EPA standards. References AlgaeBase website. Taxonomic overview of Cladophora, including nomenclature and literature references. http://www.algaebase.org/generadetail.lasso?genus_id=37&-session= abv3:44F904F21daa007C40yVi152753B 5 Dec. 2012. Bernhard, A. 2012. The Nitrogen Cycle: Processes, Players, and Human Impact. Nature Education Knowledge 3(10):25 Bitton, G. 2011. Wastewater Microbiology. 4th Ed. Wiley-Blackwell: Hoboken, NJ; 74. Buckler, D., Mayer, F., Ellersieck, M., A. Asfaw. 2005. Acute toxicity value extrapolation with fish and aquatic invertebrates. Arch. Environ. Cotam. Toxicol. 49, 546-558 (2005) Chadd, R. 2010. Assessment of aquatic invertibrates. Conservation monitoring of freshwater habitiats. PE11 1DA 2010 Chau, N. & Chrusciel, E. 2007. Leaching of technologically enhanced naturally occurring radioactive materials. Applied Radiation and Isotopes 65 (2007) 968-974 City of Wheat Ridge. What is the Wheat Ridge Stormwater Program? Wheat Ridge Stormwater Program. Retrieved December 6, 2012, from City of Wheat Ridge: http://www.ci.wheatridge.co.us/DocumentCenter/Home/View/172 Clear Creek Watershed Foundation. 2007. 2007 Clear Creek Watershed Report: Exploring Watershed Sustainability. November 19, 2007. Colorado Dept. of Public Health & Env. 2012. Nutrients Management Control Regulation 85. Water Quality Control Commission. 36 p. DRCOG (Denver Regional Council of Governments). Clean Water Plan 2009. 34 Elser, James J. 2007. Global Analysis of Nitrogen and Phosphorus Limitation of Primary Producers in Freshwater, marine and Terrestrial Ecosystems. Ecology Letters, (2007) 10: 1135-1142. EPA. 2009, February. Stormwater Wet Pond and Wetland Management Guidebook. Retrieved November 28, 2012, from Environmental Protection Agency: http://www.sbeap.org/greeninf/EPApondmgmtguide.pdf EPA. 2009. Technical Guidance on Implementing the Stormwater Runoff Requirements for Federal Projects under Section 438 of the Energy Independence and Security Act. December 2009. Retrieved on September 12, 2012. http://www.epa.gov/owow/NPS/lid/section438/pdf/final_sec438_eisa.pdf EPA. 2012. Stormwater Discharges From Municipal Separate Storm Sewer Systems (MS4s). National Pollutant Discharge Elimination System (NPDES). Retrieved December 6, 2012 from Environmental Protection Agency: http://cfpub.epa.gov/npdes/stormwater/munic.cfm Gelder, Brian, Loftis, Jim, Koski, Marci, Johnson, Brett & Saito, Laurel. Eutrophication of Reservoirs on the Colorado Front Range. Colorado Water Resources Research Institute. Colorado State University. Completion Report No. 194. 2003, April 1. Howarth, R. & Marino, R. 2006. Nitrogen as the limiting nutrient for eutrophication in coastal marine ecosystems: evolving views over three decades. Limnol. Oceanogr., 51, 364–376. Kenney, Melissa A., Reckhow, Kenneth H., & Arhonditsis. (2007). EVALUATING EUTROPHICATION-RELATED WATER QUALITY PARAMETERS IN NORTH CAROLINA LAKES AND RESERVOIRS. Water Resources Research Institute (WRRI) of The University of North Carolina. Report No. 385. January 2007. Khan, Fareed A. & Ansari, Abid Ali. 2005. Eutrophication: An Ecological Vision. The Botanical Review 71(4): 449-482. Issued 19 December 2005. The New York Botanical Garden. Lee, Fred G., Jones, Anne R., and Rast, Walter. Eutrophication of water bodies: Insights for an age-old problem. Environmental Science & Technology, Vol. 12, Page 900. August 1978. American Chemical Society. Malmqvist, B. 2005. Aquatic invertebrates in riverine landscapes. Freshwater Biology (2002) 47, 679-694. Mueller, David K. and Spahr, Norman E. Nutrients in Streams and Rivers Across the Nation— 1992-2001. U.S. Geological Survey, Reston, Virginia. 2006 35 Mwangi, J., Wang, N., Ingersoll, C., Hardesty, D., Brunson, E., Li, H., Deng, B. (2002). Toxicity of Carbon Nanotubes to Freshwater Aquatic Invertibrates. Environmental Toxicology and Chemistry. Vol 31, No 8, pp 1823-1830 (2012) The Open University. 2012. Eutrophication. Learning Space. Retrieved on September 7, 2012. http://openlearn.open.ac.uk/mod/oucontent/view.php?id=398608 Rushforth, Sarah & Sam. Phytoplankton and Low (Fluctuating) DO Relationships. Jordan River TMDL DO Linkage Symposium. 2009, April 20. Schindler, D.W. 1977. Evolution of phosphorus limitation in lakes. Science, 195, 260–262. SERC (State Environmental Resource Center). 2005. www.serconline.org. Phosphorus Pollution: Policy Issues Package. 2005, January 27. Retrieved on September 17, 2012. http://www.serconline.org/phosphorus/fact/html Sgro, G., Poole, J. Johansen, J. 2007. Diatom species composition and ecology at the animas river watershed, Colorado, USA. Western North American Naturalist, 67 (4) 510-519 2007 Smith, V.H., Tilman, G.D, & Nekola, J.C. 1999. Eutrophication: Impacts of Excess Nutrient Inputs on Freshwater, Marine, and Terrestrial Ecosystems. Environmental Pollution, Volume 100, Issues 1-3, 1999, Pages 179-196. Stednick, John D and Hall, Emile B. Applicability of Trophic Status Indicators to Colorado Plains Reservoirs. Department of Earth Resources. Colorado State University. Completion Report No. 195. USGS. Toxic Substances Hydrology Program: Eutrophication. U.S. Department of the Interior. 27 Dec, 2011. Retrieved on September 17, 2012. http://toxics.usgs.gov/definitions/eutrophication.html Williams, M., Carter, L., Fussell, R., Raffaelli, D., Ashauer, R., Boxall, A. 2011. Uptake and depuration of pharmaceuticals in aquatic invertebrates. Environmental Pollution 165 (2012) 250-258 Wright, Nebel. 1993. Environmental Science: Fourth Edition. Prentice Hall, Inc. A Paramount Communications Company. Englewood Cliffs, New Jersey 07632. Young, Erica B. & Berges, John A. Great Lakes Water Institute http://www.glwi.uwm.edu/research/aquaticecology/cladophora/page_report_discussion.p hp 6 Dec. 2012. 36 Zimmerman, L. Biological Resources: Phytoplankton. The ACE Basin Characterization Study. South Carolina Department of Natural Resources (SCDNR) & National Oceanic and Atmospheric Administration’s Coastal Services Center (NOAA CSC). Retrieved on September 12, 2012. http://nerrs.noaa.gov/doc/siteprofile/acebasin/html/biores/phyto/pytext.htm Zulkifly, Shahrizim, et al. "The epiphytic microbiota of the globally widespread macroalga Cladophora glomerata (Chlorophyta, Cladophorales)." The American Journal of Botany 99.9 (2012): 1541+. Academic OneFile. Web. 6 Dec. 2012. Acknowledgements C. Burt – Figures, tables, and content from Materials, Methods, Results, and Discussion (except for Aquatic Invertebrates and tables 6 and 7), plus Regulation 85 in Conclusion (last paragraph) A. Keiswetter – All aquatic invertebrate writings contained within Literature Review, Methods, Results, and Discussion. L. Eagle – Title, Abstract, Keywords, and Introduction E. Newman – Literature Review (wet ponds), Objectives, Study Area, Cladophora writing contained within Discussion, and Poster I. Sleeger – Conclusion 37
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