Monitoring Reports

 

Section IV. Water Quality Survey

 

Introduction

This summary documents one full year of water quality monitoring for a segment of Coffee Creek located within the Coffee Creek Watershed Preserve (Figure 1). The creek drains a fairly small watershed of approximately 16 square miles. The purpose of the monitoring project was to characterize the water quality of Coffee Creek and provide baseline data for comparison as development occurs within the project site and watershed.

 

Materials and Methods

Once per month since November of 1999 samples were collected for water quality analysis at eight sites within project boundaries (Figure 1 and Appendix 46). Samples were collected during the first week of each month when possible. Sampling dates, parameters measured, and detection limits are listed in Table 5. Additionally, discharge (cubic feet per second - ft 3 /s) was measured at each site on each sampling date. No samples were taken and no flow measured for the February 2000 sampling due to ice cover of the creek. Data was analyzed by comparing concentrations of each parameter through the year. Concentrations describe the mass of the substance contained in a unit of water, for example milligrams of phosphorus per liter (mg/l). Mass loading (mg/s) was calculated for each site on each date. Mass loading quantifies the amount of a given substance being carried in the creek at each of the eight sites per unit time. Loading is important when comparing among sites and among sampling dates because: 1) Flow can be highly variable depending on storm events; therefore, normalizing concentrations to flow removes variability. 2) Delivery of materials is important to consider. For example, a stream with little flow and high pollutant concentrations may deliver a smaller amount of pollutant to its receiving water body than a stream with higher discharge but lower pollutant concentrations. General precipitation data for Porter County was gathered from the Purdue Applied Meteorology Group's website ( http://shadow.agry.purdue.edu/sc.index.html)

 

Sample Dates

 Parameter Parameter Detection Limit

11/04/99

 Conductivity 10 umhos/cm

12/01/99

 Fecal coliform 1 col/100ml

01/10/00

 Nitrate (NO3-) 0.50 mg/l

03/06/00

 pH

04/06/00

 Total suspended solids (TSS) 1.0 mg/l

05/04/00

 Ammonia (NH3) 0.10 mg/l

06/08/00

 Total Kjeldahl nitrogen (TKN) 0.10 mg/l

07/05/00

 Dissolved oxygen (DO) 0.10 mg/l

08/02/00

 Total phosphorus (TP) 0.10 mg/l

09/12/00

10/05/00

11/09/00

12/06/00

Table 5. Sampling dates, parameters assessed, and parameter detection
limits for 1999-2000 water quality monitoring of Coffee Creek.


Results and Discussion

Table 6 shows flow for each site by date. Sites 1, 2, and 3 had very low and sometimes unmeasurable rates of flow, while the remaining five sites had higher discharge rates. Flow peaked during the September 2000 sampling due to nearly 3" of rain that fell the day of the sampling (Figure 19).

Figure 19. Daily precipitation from November 1999 through January 2001 for Porter County, Indiana. Data source: http://shadow.sgry.purdue.edu/sc.index.html

Sampling Site

Date

1

2

3

4

5

6

7

8

11/14/99

0.1

0.1

0.1

6.6

NA

3.3

5.8

6.9

12/1/99

0.1

**

0.2

6.3

6.7

8.5

11.8

10.1

1/10/00

0.4

**

**

10.6

11.6

10.9

11.3

10.2

2/1/00

*

*

*

*

*

*

*

*

3/6/00

0.1

**

0.3

23.2

12.2

14.8

23.2

16.3

4/6/00

**

**

0.1

12.7

11.2

9.5

12.8

8.2

5/4/00

**

**

0.5

17.5

9.7

9.8

19.6

7.7

6/8/00

**

**

0.8

28.3

12.6

7.4

18.5

16.8

7/5/00

**

0.1

0.2

15.2

15.1

19.3

28.1

23.8

8/2/00

**

**

**

8.2

11.8

9.2

8.9

16.6

9/12/00

3.8

**

1.0

74.8

51.6

48.7

55.1

68.6

10/5/00

**

**

0.1

12.8

11.1

14.6

13.3

20.2

11/9/00

**

**

**

6.1

12.9

7.1

14.3

17.7

12/6/00

*

*

*

11.5

13.6

19.6

18.2

19.0

Table 6. Discharge for all sites by sampling date for the 1999-2000 monitoring season. A single asterisk (*) indicates that no sample was taken due to ice coverage. A double asterisk (**) indicates that the water was stagnant or not flowing. NA means that the data was not available.

Figure 20. pH values for the 1999-2000 water quality monitoring season.

Figure 20 shows that Coffee Creek is a fairly alkaline stream, with pH values near 8. Dissolved oxygen concentrations ranged between 8 and 12 mg/l. These levels are conducive to cold-water fish, like salmonids, which require higher oxygen levels than their warm-water counterparts like bass and bluegill. Figures 21-24 document concentration and loading data for two different forms of nitrogen: nitrate (NO 3 - ), a dissolved, inorganic component, and total Kjeldahl nitrogen (TKN), an organic component including ammonia found in plant and animal materials. Nitrate levels were very low and undetectable for most sites on most dates. Concentrations were well below Indiana state drinking water standards of 10 mg/l (per 327 IAC 2). Site 1, located on Shooter Ditch and Site 3 consistently had higher TKN concentrations than most other sites. Site 1 had very low flow due to an upstream beaver dam and was not sampled after August because the water was stagnant. The increased organic N concentrations measured at this site may be due to organic material collection and decomposition. No data are shown for total phosphorus because levels never exceeded laboratory detection limits of 0.10 mg/l. Low nutrient levels (like those measured in Coffee Creek) usually correspond with low productivity, which is typical of small, "headwater" streams. Unproductive streams typically contain low quantities of organic matter. Because litter is scarce, decomposition rates remain low and oxygen remains available for use by other aquatic life.

Figures 25 and 26 portray total suspended solid (TSS) data for the 1999-2000 monitoring year. All TSS concentrations fell under the Indiana state standard of 750 mg/l. However, TSS did peak in September following a large rain event. Concentrations at Site 8 reached 148 mg/l (90 mg/l has been shown to be deleterious to lithotrophic fish species like coho salmon and steelhead that require gravel and cobble for successful spawning). Erosion both from the watershed and the stream occurred due to stormwater runoff causing the spike in TSS concentration and loading. Concentration and loading increased significantly between Sites 7 and 8 suggesting erosion of unstabilized surfaces and soils in this area. Stream and bank restoration projects (like those already completed in some areas) can slow these erosive processes and reduce sediment loading into fish habitat.

Figure 21. Nitrate concentration data for the 1999-2000 water quality sampling season.

Figure 22. Nitrate loading data for the 1999-2000 water quality sampling season.
Figure 23. Total Kjeldahl nitrogen concentration data for the 1999-2000 water quality sampling season.

Figure 24. Total Kjeldahl nitrogen loading data for the 1999-2000 water quality sampling season.

Figure 24. Total Kjeldahl nitrogen loading data for the 1999-2000 water quality sampling season.

Figure 25. Total suspended solid concentration data for the 1999-2000 water quality sampling season.

Figure 26. Total suspended solid loading data for the 1999-2000 water quality sampling season.

Fecal coliform concentrations and loading were also quite low (Figures 27 and 28). Although few samples exceeded the state standard of 235 col/100ml, the October sampling documented a spike in fecal coliform levels. Because the spike was not concurrent with any precipitation event (Figure 19), it is likely that the bacteria were introduced directly to or near the stream, perhaps from natural sources. Additionally, flow was low or "baseline" at this time, which would serve to concentrate the organisms in a smaller volume of water.

Figure 27. Fecal coliform concentration data for the 1999-2000 water quality monitoring
season. The dashed line represents the Indiana state standard for recreational water bodies.


Figure 28. Fecal coliform loading data for the 1999-2000 water quality monitoring season.