Streamwatch Project
Middle Run and Lower Mainstem of White Clay Creek: Site 14
Site 14 on the Lower Mainstem is found below the confluence of the East, West, and Middle Branches, downstream of Yeatman Road. Land use was typical of the study average: mostly pasture/hay fields with some row crops and forest. This site is on the White Clay Creek Preserve in PA so a large portion of the stream above the sampling location has an intact riparian forest (a.k.a. a stream buffer) providing a barrier against potential impacts. Water chemistry variables are comparable to the study wide average and indicate no obvious anomalies.
Average total density was 7400 individuals/m2 and ranged from 145 individuals/m2 in 1993 to 20,300 individuals/m2 in 1998. Chironomid midges dominated the samples: on average midges made up to 85% of the total density. The MAIS score averaged 3.8 (Poor) and was more similar to the upstream site on the East Branch (Site 16, MAIS = 3.8) than the upstream site on the Middle/West Branches (Site 7, MAIS = 6.7). This implies that the East Branch contributed to more of the degradation that was measured at Site 14 on the Lower White Clay Creek. Long-term trends suggest no improvement in water quality from 1994 through 2005.
| Location | |
|---|---|
| Site number | 14 |
| Description | Below confluence of the East, West and Middle Branches, downstream of Yeatman Rd in WCC Preserve |
| Lat Long (hr min sec) | 39°44.910’ N, -75°46.168’ W |
| Land Use | |
| Watershed area above site (km2) | 153 |
| Population density in 2000 (#/km2) | 152 |
| % Population increase from 1990 to 2000 | 37 |
| Percent pasture/hay | 51 |
| Percent cultivated crops | 18 |
| Percent forest | 20 |
| Chemistry* | |
| Nitrate (mg/L) | 3.89 |
| Ammonium (mg/L) | 0.01 |
| Total Dissolved Phosphorus (mg/L) | 0.033 |
| Soluble Reactive Phosphorus (mg/L) | 0.049 |
| Sulfate (mg/L) | 18.37 |
| Alkalinity (as mg/L CaCO3) | 43.16 |
| pH | 8.17 |
| Conductivity (μmhos) | 210 |
| Dissolved organic carbon (mg/L) | 1.88 |
| Macroinvertebrate Data | |
| years sampled | 1994-2001, 2003-2005 |
| MAIS score | 3.8 |
| 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 | Tipulidae (crane flies) |
| 3rd most abundant macroinvertebrate | Hydropsychidae (common netspinner caddisflies) |
| 4th most abundant macroinvertebrate | Oligochaeta (aquatic worms) |
| 5th most abundant macroinvertebrate | Empididae (dance flies) |
*See Methods for number of years each chemistry variable was measured.