Section IV. Water Quality Survey

Introduction

This report documents the third year of water quality monitoring for the portion of Coffee Creek located within Coffee Creek Center (Figure 1). Coffee Creek drains approximately 16 square miles of northeastern Porter County, Indiana. The creek flows north to converge with the east branch of the Little Calumet River, which ultimately flows into Lake Michigan at Burns Harbor in Portage, Indiana. The purpose of the monitoring project is to characterize the water quality of Coffee Creek and to track any changes in water quality as development occurs within the project site and watershed. Development has begun within the Coffee Creek Center. The 2002 water quality report documents water quality within Coffee Creek as development is occurring.

Materials and Methods

Each year since the fall of 1999 water quality sampling has been conducted in Coffee Creek in the Coffee Creek Center. From November 1999 to December 2000 samples were collected once per month at eight sites within the Coffee Creek Center. Early in 2001 the sampling scheme was revised to exclude three of the sampling locations that were considered redundant. Subsequently, the remaining sampling sites were renumbered. (See the 2001 Coffee Creek Monitoring Report for a more detailed description of the site numeration modification that occurred when the sampling protocol changed.) Samples were collected on six dates during 2002 at five sites located in the Coffee Creek Center (Figure 1). Sampling occurred during both base and storm flow conditions and during the dormant and growing seasons.

Water quality parameters and detection limits are listed in Table 6. The water quality samples were analyzed for a variety of physical, biological, and chemical parameters. The following is a brief description of each of these parameters.

Parameter	Parameter Detection Limit
Dissolved Oxygen (DO)	0.10 mg/l
PH	--
Conductivity	10 umhos/cm
Nitrate-Nitrogen (NO 3 - -N)	0.05 mg/l
Ammonia-Nitrogen (NH 3 -N)	0.01 mg/l
Total Kjeldahl Nitrogen (TKN)	0.50 mg/l
Total Phosphorus (TP)	0.10 mg/l
Total Suspended Solids (TSS)	1.0 mg/l
E. coli	1 col/100ml

Table 6. Parameters assessed and parameter detection limits for 2002 water quality
monitoring of Coffee Creek and its tributaries within the Coffee Creek Center.

Temperature

Temperature determines the form, solubility, and toxicity of a broad range of aqueous compounds. For example, water temperature affects the amount of oxygen dissolved in the water column. Cold water holds more oxygen than warm water. This is of particular importance in Coffee Creek since Coffee Creek harbors coldwater salmonid species. These fish require more oxygen, and thus colder water, than warmwater fish species. Water temperature also regulates the activity of life associated with the aquatic environment. Since essentially all aquatic organisms are 'cold-blooded' the temperature of the water regulates their metabolism and ability to survive and reproduce effectively (EPA, 1976). The Indiana Administrative Code (327 IAC 2-1-6) sets maximum temperature limits for Indiana streams. The IAC lists different limits for coldwater and warmwater streams. Although Coffee Creek is not classified as a coldwater stream in the IAC, the coldwater temperature limits may serve as a better guide for protecting Coffee Creek's biota. The IAC states that for coldwater streams "the maximum temperature rise above natural shall not exceed 1.1 o C at any time or place..." Additionally, temperatures in coldwater streams should not exceed 21.1 o C at any time and shall not be above 18.3 o C during spawning and imprinting periods.

Oxygen

Dissolved oxygen (DO) is the dissolved gaseous form of oxygen. It is essential for respiration of fish and other aquatic organisms. Fish need at least 3-5 parts per million (ppm) of DO. Coldwater fish such as trout generally require higher concentrations of DO than warmwater fish such as creek chub. The IAC sets minimum DO concentrations at 6 mg/l for coldwater fish. DO enters water by diffusion from the atmosphere and as a byproduct of photosynthesis by algae and plants. Excessive algae growth, accompanied by high levels of photosynthetic activity, can over-saturate (greater than 100% saturation) the water with DO. Dissolved oxygen is consumed by respiration of aquatic organisms, such as fish, and during bacterial decomposition of plant and animal matter.

pH

The pH of water describes the concentration of acidic ions (specifically H+) present in water. The pH also determines the form, solubility, and toxicity of a wide range of other aqueous compounds. The IAC establishes a range of 6 to 9 pH units for the protection of aquatic life. pH concentrations in excess of 9 are considered acceptable when the concentration occurs as daily fluctuations associated with photosynthetic activity.

Conductivity

Conductivity is a measure of the ability of an aqueous solution to carry an electric current. This ability depends on the presence of ions and on their total concentration, mobility, and valence (APHA, 1995). At low discharge, conductivity of a stream is higher than it is following storm events because the water moves more slowly across or through ion-containing soils and substrates during base flow. Carbonates and other charged particles dissolve into the slow moving water, thereby increasing the conductivity of a water body.

Rather than setting a conductivity standard, the Indiana Administrative Code set a standard for dissolved solids (750 mg/l). Multiplying a dissolved solids concentration by a conversion factor of 0.55 to 0.75 mmhos per mg/l of dissolved solids roughly converts a dissolved solids concentration to specific conductance (Allan, 1995). Thus converting the IAC dissolved solids concentration standard to specific conductance by multiplying 750 mg/l by 0.55 to 0.75 mmhos per mg/l yields a specific conductance range of approximately 1000 to 1360 mmhos.

Nutrients (Nitrogen and Phosphorus)

Nutrients are a necessary component of aquatic ecosystems. Ecosystem primary producers (i.e. plants) require nutrients for growth. Growth of the primary producers ultimately supports the remainder of the organisms in the ecosystem's food web. Insufficient nutrient levels in stream and lake water can limit the size and complexity of biological communities living in the stream or lake. In contrast, excessive levels of nutrients in lake or stream water alter biological communities by promoting nuisance species growth. For example, high concentrations of total phosphorus in lake water (>0.03 mg/l) create ideal conditions for nuisance algae growth. In extreme cases, lake algae growth can exclude rooted macrophyte growth and shift fish community composition.

In low order streams such as Coffee Creek aquatic plants exist primarily as periphyton (algae attached to substrate or other surfaces in the stream). Light availability and flow regime limit the establishment of rooted macrophytes and phytoplankton populations that are more common in lakes and large river systems. As small stream ecosystems' primary producers, periphyton support higher members of the stream food web (invertebrates, fish). Nutrients are one of the factors that limit periphyton growth in streams and thus are included in stream water chemistry analyses.

Phosphorus and nitrogen are common nutrients governing plant growth. (When diatoms dominate the periphyton or planktonic community, silica is also an important nutrient.) Sources of phosphorus and nitrogen include fertilizers, human and animal waste, atmospheric deposition in rainwater, and yard waste or other plant material that reaches streams. Nitrogen can also diffuse from the air into streams. Atmospheric nitrogen is then "fixed" by certain algae species (cyanobacteria) into a usable form of nitrogen. Because of this readily available source of nitrogen (the air), phosphorus is usually the "limiting nutrient" in aquatic ecosystems.

Phosphorus and nitrogen exist in several forms in water. The two common phosphorus forms are soluble reactive phosphorus (SRP) and total phosphorus (TP). SRP is the dissolved form of phosphorus. It is the form that is "usable" by algae. Algae cannot directly digest and use particulate phosphorus for growth. Total phosphorus is a measure of both dissolved and particulate forms of phosphorus. The most commonly measured nitrogen forms are nitrate-nitrogen (NO 3 ), ammonia-nitrogen (NH 3 ), and total Kjeldahl nitrogen (TKN). Nitrate is a dissolved form of nitrogen that is commonly found in surface water where oxygen is readily available. In contrast, ammonia-nitrogen is generally found in water where oxygen is lacking. Ammonia-nitrogen, or more correctly the ionized form of ammonia-nitrogen (ammonium), is a dissolved form of nitrogen and the one utilized by algae for growth. The TKN measurement parallels the TP measurement to some extent. TKN is a measure of the total organic nitrogen (particulate) and ammonia-nitrogen in the water sample.

Indiana possesses nitrate-nitrogen and ammonia-nitrogen standards for its water bodies. These standards apply to all state water bodies except those designated as Limited Use waters. The nitrate-nitrogen standard is 10 mg/l; nitrate-nitrogen concentrations exceeding 10 mg/l in drinking water are considered hazardous to human health (Indiana Administrative Code IAC 2-1-6). Because both temperature and pH govern the toxicity of ammonia for aquatic life, these factors are weighed in ammonia the standard. According to the IAC, maximum unionized ammonia concentrations within the temperature and pH ranges measured for the study streams should range between 0.044-0.149 mg/l.

Total suspended solids

Total suspended solids refer to all particles suspended or dissolved in stream water. Sediment, or dirt, is the most common solid suspended in stream water. The sediment in stream water originates from many sources, but a large portion of sediment entering streams comes from active construction sites or other disturbed areas such as unvegetated stream banks.

Suspended solids impact streams in a variety of ways. When suspended in the water column, solids can clog the gills of fish and invertebrates. As the sediment settles to the creek bottom, it covers spawning and resting habitat for aquatic fauna, reducing the animals' reproductive success. Suspended sediments also impair the aesthetic and recreational value of a waterbody. Few people are enthusiastic about having a picnic near a muddy creek or wading in silty water. Pollutants attached to sediment also degrade water quality.

Pathogens

Bacteria, viruses, and other pathogens are contaminants of concern in both rural and urban watersheds. Common sources of pathogens include human and wildlife waste, fertilizers containing manure, previously contaminated sediments, septic tank leachate, combined sewer overflows, and illicit connections to stormwater sewers or drainage tiles. Pathogenic organisms can present a threat to human health by causing a variety of serious diseases, including infectious hepatitis, typhoid, gastroenteritis, and other gastrointestinal illnesses. Thus, pathogens can impair the recreational value of a stream. Some pathogens can also impair biological communities. Water quality researchers and monitoring programs utilize E. coli as an indicator for the presence of pathogens in water. According to the Indiana Administrative Code, E. coli concentrations should not exceed 235 colonies/100 mL in any one grab sample within a 30-day period.

Results and Discussion

Appendix 25 presents the raw water quality data collected in Coffee Creek and its tributaries in 2002. For the nutrient and sediment water quality parameters, pollutant concentration and mass loading rates are both reported. Concentrations express the mass of a substance per unit volume, for example milligrams of total suspended solids per liter (mg/l). Mass loading describes the quantity of a substance in the creek at each of the five sampling sites per unit time (kg/day). Loading is important when comparing among sites and among sampling dates because: 1) Flow can be highly variable; therefore, normalizing concentrations to flow eliminates variability. 2) Delivery of materials is important to consider. For example, a stream with high discharge but a low pollutant concentration may deliver a larger portion of a pollutant to its receiving body than a stream with a higher pollutant concentration but lower discharge. It is the total amount (mass) of nutrients, sediment, and bacteria actually delivered from the watershed that is the most important when considering the effects of these materials downstream. The remaining water quality parameters are reported in the appropriate units for each parameter.

Stream discharge measured during the six water quality sampling events is shown in Figure 17. The highest measured discharge occurred during April sampling event. Flows were highest during this sampling event due to nearly 1" of rain falling during the preceding days. Generally, Sites 1 and 3 possessed the lowest flows. Flows at Site 1 are low mainly because a beaver dam blocks Shooter Ditch just upstream of the sampling location. The beaver dam limits the volume of water moving from the headwaters of Shooter Ditch to Coffee Creek. Likewise, Site 3 is a small stream that drains only a small area and does not carry much water. In 2002, low precipitation throughout the summer and fall limited water volumes in this tributary. (Table 4 in the Fish Report section of this document contains monthly precipitation levels for 2002.) Although water remained in isolated pools throughout the fall, water did not flow in the portion of the tributary where Site 3 is located. The remaining three sites are located along the mainstem of Coffee Creek. These three sites possessed higher discharge rates than the two tributary sites. However, flow generally was lower at all sites during 2002 than in previous years.

Figure 17. Discharge collected at Coffee Creek for the 2002 monitoring season.

Temperatures measured within Coffee Creek and its tributaries varied from 0.9º C to 24.6º C. The highest temperatures were observed during the growing season samples collected in May and July; temperatures collected at this time ranged from 16.5º C at Sites 3 and 5 to 24.6º C at Site 1. Temperatures measured during the dormant season, February and November, were generally lower than those measured during the growing season, ranging from 6.8º C at Site 1 to 8.4º C at Site 2. Site 3, when water was present and flowing, generally contained the coldest water of any of the sites. Streamside vegetation and canopy cover that shade the water likely prevented heat gain at this site. The higher temperatures measured at Site 1 throughout much of the 2002 monitoring season were likely due to its shallow nature and lack of riparian vegetation. All temperatures measured in Coffee Creek and its tributaries within Coffee Creek Center were below the maximum temperature limit suitable to protect warmwater aquatic life. However, temperatures measured in the mainstem of Coffee Creek (Sites 2 and 5; July 2002) exceeded water temperatures required to protect coldwater fish (21º C). Although Coffee Creek has not been designated as a coldwater stream, it does support coldwater fish (Appendix 23 of the fish report). Temperatures measured during the 2002 sampling season may limit the survival and reproductive success of sensitive coldwater fish species such as salmonids.

Dissolved oxygen (DO) concentrations varied from 2.9 mg/l to 13.3 mg/l. Coffee Creek mainstem sites, Site 2, 4, and 5, possessed the highest DO concentrations (9.6-13.3 mg/l). Generally, Site 1 exhibited the lowest dissolved oxygen concentration of any of the sampling sites ranging from 2.9 to 9.7 mg/l. DO at all sites, except Site 1 from May through October, exceeded the Indiana state minimum standard of 6 mg/l for coldwater streams indicating that oxygen was sufficient to support aquatic life.

Because DO varies with temperature (cold water can contain more oxygen than warm water), it is relevant to consider DO saturation values. This refers to the amount of oxygen dissolved in water compared to the maximum possible when water is in equilibrium with the atmosphere and is fully saturated with oxygen. For example, 18 ° C water is 100% saturated if it has a DO concentration of 9.5 mg/l. In streams that are not fully saturated with dissolved oxygen, decomposition processes within the stream may be consuming oxygen more quickly than it can be replaced by diffusion from the atmosphere, and/or flow in the streams is not turbulent enough to entrain sufficient oxygen. Stream data indicate that fully saturated dissolved oxygen conditions did not occur at any time during the 2002 monitoring season. Percent dissolved oxygen saturation during the 2002 monitoring season averaged 92% at Coffee Creek mainstem sites and 66% for the Coffee Creek tributaries, Sites 1 and 3. Water at Site 1 was less than 60% saturated with dissolved oxygen during four of the six sampling events. The under-saturated water in Shooter Ditch (Site 1) is likely due to bacterial decomposition of organic matter that has accumulated below the beaver dam at this site. Additionally, the slow water velocity at this site limits the entrainment of new dissolved oxygen.

In general, both conductivity and pH values fell within acceptable ranges. Conductivity values measured in Coffee Creek and its tributaries ranged from 376 to 1170 mmhos during the 2002 monitoring season. Most of the conductivity measurements fell below the lower end of the range obtained by converting the IAC dissolved solids standard to specific conductance (1000-1360 mmhos); all of these measurements fell below the upper end of the range. Site 1 and 3 generally possessed higher conductivity levels compared to the other three sites. This suggests that the tributaries are contributing ions to the mainstem. For the most part, conductivity measured during the April storm flow sampling event was lower than conductivity measured during the other five sampling events. Higher flows tend to dilute ion concentrations and do not allow enough time for soil ion dissolution to occur. Values of pH fell within the range of 6-9 units established by the Indiana Administrative Code to protect aquatic life. Values at the sample sites ranged from 7.1-8.4 during the six sampling events.

Nitrate-nitrogen concentrations and loading rates in the Coffee Creek Center streams are illustrated in Figures 18 and 19. Site 3 exhibited the highest nitrate-nitrogen concentrations (0.48-2.32 mg/l) of any of the sites. Nitrate-nitrogen concentrations measured at the remaining four sites throughout the 2002 monitoring season were low (<0.05-1.32 mg/l). Base flow sample concentrations ranged from 0.17-0.83 mg/l, while storm flow sample concentration ranged from 1.05-2.08 mg/l. During base flow, nitrate-nitrogen concentrations at all sites except Site 3 in February were below 1.0 mg/l, the nitrate concentration standard the Ohio EPA set to protect aquatic life in Ohio streams (Ohio EPA, 1999). (Indiana lacks nutrient numeric criteria for protecting aquatic life.) All nitrate-nitrogen concentrations remained below the IAC standard of 10 mg/l throughout 2002. Generally, nitrate-nitrogen concentrations measured during the 2002 monitoring season were similar to those measured in the preceding two seasons. Site 5 exhibited the greatest loading rate for nitrate-nitrogen. This is expected. As the site located furthest downstream, Site 5 receives pollutants from all the other sites. (Appendix 25 contains water quality data from 2002; Appendix 26 lists water quality data from 1999 to 2002.)

Figure 18. Nitrate-nitrogen concentration data for 2002 water quality monitoring season.

Figure 19. Nitrate-nitrogen loading data for the 2002 water quality monitoring season.

Ammonia-nitrogen concentrations generally fell below the maximum concentration set by the IAC for the protection of aquatic life (Figure 20). (Because the toxicity of ammonia depends both on temperature and pH, the IAC standard varies based on the pH and temperature of the water.) Site 1 generally contained the highest ammonia-nitrogen concentration of any of the sampling sites (0.11-0.51 mg/l). Ammonia-nitrogen concentrations exhibited at Site 1 during the October and November were the only concentrations to exceed the IAC standard. The October sample collected at this site also contained low dissolved oxygen concentrations suggesting that organic decomposition was occurring at this site. (Ammonia is a byproduct of decomposition.) All other sites contained ammonia-nitrogen concentrations conducive to the support of aquatic life. Like nitrate-nitrogen concentrations, ammonia-nitrogen concentrations measured during the 2002 monitoring season were similar to those measured in the preceding two seasons. Sites 4 and 5 generally exhibited the highest ammonia-nitrogen loading rates (Figure 21). (Appendix 25 contains water quality data from 2002; Appendix 26 lists water quality data from 1999 to 2002.)

Figure 20. Ammonia-nitrogen concentration data for 2002 water quality monitoring season.

Total Kjeldahl nitrogen (TKN) concentrations were elevated at all sites during the A

Figure 21. Ammonia-nitrogen loading data for the 2002 water quality monitoring season.

pril sampling event; concentrations ranged from 1.3-1.9 mg/l (Figure 22). Generally, concentrations throughout the remainder of the monitoring season were low (< 1.1 mg/l) except at Sites 1 and 3 where concentrations greater than 1.1 mg/l were observed during two of the base flow sampling events. Site 3 contained the highest TKN concentrations in the spring and early summer, while Site 1 possessed the highest TKN concentrations in July and October. The high TKN levels at Sites 1 and 3 reflect the accumulation of organic materials at these sites. Generally, total Kjeldahl nitrogen concentrations measured during the 2002 monitoring season were similar to those measured in the preceding two seasons. As observed with the other nitrogen parameter data, Site 5 exhibited the greatest loading rate for total Kjeldahl nitrogen

(Figure 23). As the site located furthest downstream, Site 5 receives pollutants from all the other sites. (Appendix 25 contains water quality data from 2002; Appendix 26 lists water quality data from 1999 to 2002.)

Figure 22. Total Kjeldahl nitrogen concentration data for the 2002 water quality monitoring season. Note : Although sample collection occurred during November, TKN concentrations are not reported. A laboratory equipment malfunction required that TKN samples be analyzed a second laboratory. The second laboratory's TKN detection level was well above the concentrations typically measured in Coffee Creek samples; therefore, November TKN concentrations were not included in 2002 water quality monitoring report.

Figure 23. Total Kjeldahl nitrogen loading data for the 2002 water quality monitoring season.

Total phosphorus concentrations are not displayed because levels only exceeded the laboratory detection level of 0.10 mg/l at one site regularly (Site 1; 0.11-0.54 mg/l) and on only one occasion at the other four sites (Site 2; 0.11 mg/l, July 2002). The highest concentration recorded at any of the sites during the 2002 monitoring season occurred at Site 1 during the October sampling event. Total phosphorus concentrations measured at Site 1 exceed the Ohio EPA standard concentration (0.08 mg/l) for protection of aquatic fauna. The high total phosphorus concentrations measured at Site 1 suggest that Shooter Ditch is more productive than the other sites. High TP levels at this site also correspond with elevated TKN concentrations measured at the same location, suggesting that higher levels of organic material are present at this site relative to other sites.

In general, concentrations and loading rates of total suspended solids (TSS) measured during the April storm flow event were greater than those measured throughout the monitoring season (Figures 24 and 25). Higher overland flow velocities typically result in the increase in sediment particles in runoff. Additionally, greater streambank and stream bed erosion typically occurs during high flow. Therefore, higher concentrations of suspended solids are expected in storm flow samples. The increased discharge associated with storm events magnifies the high TSS concentrations resulting in high loading rates during storm events. Total suspended solid concentrations measured in the Coffee Creek Center sites exceeded the 80 mg/l level known to be deleterious to aquatic life and the 90 mg/l level know to negatively impact lithophilous fish (Waters, 1995) on only one occasion. This occurred during the October sampling event at Site 1 and corresponds with high TKN and TP concentrations suggesting the presence of organic material in the water column. TSS concentrations measured during the storm flow sampling (April) were higher than those observed in the preceding years. This may be due to an increase in bare soil erosion from overland flow within developing areas within or upstream of Coffee Creek Center. However, throughout the rest of the year total suspended solids concentrations were similar to those measured in the preceding two seasons. Generally, Site 5 possessed the highest TSS loading rate. This is expected because, as the site furthest downstream, Site 5 receives pollutants from all other sites. Appendix A contains water quality data from 2002; Appendix B lists water quality data from 1999 to 2002.)

Figure 24. Total suspended solids concentration data for the 2002 water quality monitoring season.

Figure 25. Total suspended solids loading data for the 2002 water quality monitoring season.

As expected, the E. coli concentrations observed during the February and November sampling events were low measuring 10-220 col/100 ml (Figure 26). During the April (storm flow) and July (summer) sampling event, E. coli concentrations measured at the three Coffee Creek mainstem sites (Sites 2, 4, and 5) exceeded the Indiana state standards for E. coli (235 col/100 ml; Figure K). Concentrations in violation of the standard ranged from 310 to 1,600 col/100 ml. The April storm flow sample collected at Site 4 possessed the highest E. coli concentration (1,600 col/100 ml). Relative to other streams in the state, the E. coli concentrations present in Coffee Creek Center streams are low. White (unpublished) found the average E. coli concentration in Indiana streams to be approximately 650 colonies/100 ml. Conversely, E. coli concentrations in Coffee Creek Center streams possessed an average concentration of 235 col/100 ml. Nonetheless, contact with stream water during summer months may present a health risk based on the 2002 monitoring data. Generally, E. coli concentrations measured during the 2002 monitoring season were higher to those measured in the preceding two seasons. E. coli concentrations measured in 2001 ranged from <1-650 col/100 ml. The 2001 average E. coli concentration was slightly lower average concentration (233 col/100 ml) than the 2002 average. The difference in the 2001 and 2002 E. coli concentrations was not statistically significant (p=0.05). (Appendix 26 contains water quality data for 1999-2002.)

Figure 26. E. coli concentration for the 2002 water quality monitoring season. The dashed line represents the Indiana state standard for recreational water bodies (235 col/100 ml).

Section IV. Conclusions and Recommendations

In general, stream chemistry samples collected during 2002 at locations in the Coffee Creek Center indicate good water quality. Generally, Sites 1 and 3 possessed poorer water quality than the Coffee Creek mainstem sites. Site 1 routinely exhibited higher ammonia-nitrogen, total Kjeldahl nitrogen, total phosphorus, and total suspended solid concentrations than the other sites. The site was exhibited low dissolved oxygen levels. During the three sampling events from which samples were collected at Site 3, the site possessed higher nitrate-nitrogen and total Kjeldahl nitrogen concentrations than the other sites. Within the mainstem, water quality was better. Nitrate-nitrogen and ammonia-nitrogen concentrations in the mainstem were all at or below state standards; all nearly nitrate-nitrogen, total phosphorus, and total suspended solids concentrations in the mainstem during base flow conditions were below thresholds observed in the scientific literature to protect aquatic life. Collectively, the data indicate that Coffee Creek water quality is conducive for supporting aquatic life, but the creek's tributaries offer poor refuges. Nutrient and sediment concentrations measured during 2002 were similar to those measured during the 1999 to 2001 water quality sampling seasons; development does not appear to have negatively impacted water quality within Coffee Creek Center. However, E. coli concentrations measured during the growing season exceeded state standards for the protection of human health. People should proceed with caution if full body contact activities are planned during the summer months.

Nutrient and sediment loads observed in Coffee Creek Center streams follow the typical pattern. Site 5 possessed the highest nitrate-nitrogen, total Kjeldahl nitrogen, and total suspended solids loads. This is to be expected. As the site located furthest downstream, Site 5 receives the pollutants from all other sites. In contrast, Site 4 possessed the greatest load of ammonia-nitrogen. Nutrient and sediment loads were highest during the April storm flow sampling event. Increased overland flow generally results in an increase in nutrient and sediment loading rates due to erosion and increases in stream discharge.

Continued water quality monitoring within the Coffee Creek Center boundaries is recommended to document any water quality degradation that may occur as the watershed changes. Information gained from the water quality monitoring program will be helpful in addressing any water quality degradation that may occur. It is not recommended that any of the sites be relocated at this time. Water quality should continue to be assessed five to six times per year within Coffee Creek Center. Additional efforts should be made to minimize pollutant inputs from Shooter Ditch (Site 1). The beaver dam, which currently reduces sediment and nutrient loading from Shooter Ditch from entering Coffee Creek, should not be utilized as the only method for maintaining Coffee Creek's water quality. Lack of maintenance, heavy rainfall, and high water pressure from upstream can reduce the stability of the beaver dam. If additional measures are not instituted to stabilize the beaver dam, it is likely that destruction of the dam will release the nutrients and/or sediment currently trapped by the beaver dam to Coffee Creek.