Streamwatch Project
Middle Branch of White Clay Creek: Site 6
This site is situated upstream from Mercer Mill Road, just upstream of the confluence with the West Branch. The predominant land use in the watershed is pasture/hay fields. Row crop agriculture and forests are also prevalent. The number of people in the watershed is typical of sites in this study. Water chemistry results are similar to the study wide average and indicate no obvious impacts at the time sampling occurred.
Total density averaged 9800 individuals/m2 and ranged from 800 individuals/m2 to 26,600 individuals/m2. Chironomids were the most dominant taxa and usually made 80% of the total density, while EPT (mainly Hydropsychid caddisflies) made approximately 15% of the total. Total Richness ranged from 5-13 taxa/200 individuals and typically 40% of those taxa were EPT. Of the 10 years sampled, half the MAIS scores were considered Fair and half were Poor. The average MAIS score was 5.3 (Poor). Although MAIS scores indicated a period of improvement from 1998-2003, more recent years (2004 and 2005) suggest this site remains highly degraded.
| Location | |
|---|---|
| Site number | 6 |
| Description | Upstream from Mercer Mill Road, near the confluence with the West Branch |
| Lat Long (hr min sec) | 39°46.001 ’ N, -75°47.702 ’ W |
| Land Use | |
| Watershed area above site (km2) | 35 |
| Population density in 2000 (#/km2) | 136 |
| % Population increase from 1990 to 2000 | 30 |
| Percent pasture/hay | 53 |
| Percent cultivated crops | 22 |
| Percent forest | 18 |
| Chemistry* | |
| Nitrate (mg/L) | 4.19 |
| Ammonium (mg/L) | 0.01 |
| Total Dissolved Phosphorus (mg/L) | 0.053 |
| Soluble Reactive Phosphorus (mg/L) | 0.065 |
| Sulfate (mg/L) | 19.03 |
| Alkalinity (as mg/L CaCO3) | 33.0 |
| pH | 7.85 |
| Conductivity (μmhos) | 195 |
| Dissolved organic carbon (mg/L) | 2.05 |
| Macroinvertebrate Data | |
| years sampled | 1994-1999, 2001, 2003-2005 |
| MAIS score | 5.3 |
| water quality based on MAIS score | Poor |
 Click on macroinvertebrate name to view a photo | |
| 1st most abundant macroinvertebrate | Chironomidae (midges) |
| 2nd most abundant macroinvertebrate | Hydropsychidae (common netspinner caddisflies) |
| 3rd most abundant macroinvertebrate | Tipulidae (crane flies) |
| 4th most abundant macroinvertebrate | Oligochaeta (aquatic worms) |
| 5th most abundant macroinvertebrate | Simuliidae (black flies) |
*See Methods for number of years each chemistry variable was measured.