Streamwatch Project
Middle Run and Lower Mainstem of White Clay Creek: Site 22
Site 22 is at Harmony Brook Park, downstream of Pike Creek. This is the largest sampling location we have on White Clay Creek. The number of people in the watershed is relatively high so it is not surprising the large amount of developed area (16%) and impervious surface (5%). What is beneficial for the stream is the large amount of forest in the watershed (23%). Slightly high dissolved organic carbon suggests organic enrichment, but this should be confirmed with additional sampling (we only measured DOC in 1997). Other water chemistry variables we examined indicated no obvious problems.
Total density averaged 6600 individuals/m2 and ranged from 200 individuals/m2 in 1996 to 17,000 individuals/m2 in 2004. Chironomid midges, a group relatively tolerant to pollution, typically made >85% of the total numbers. Total Richness and EPT Richness averaged 7 and 1 taxa/200 individuals, respectively. Of the nine sample dates, MAIS rated eight of them as Poor, only in 2003 (an extremely low density year) was the site considered to have Fair water quality. Sites 22 and 21 (upstream) had the overall lowest MAIS scores for the Lower Mainstem. The MAIS score at Site 22 averaged 2.9 (Poor) and ranged from 0.4 to 7.
| Location | |
|---|---|
| Site number | 22 |
| Description | At Harmony Hills, downstream of Pike Creek |
| Lat Long (hr min sec) | 39°42.060’ N, -75°41.012’ W |
| Land Use | |
| Watershed area above site (km2) | 225 |
| Population density in 2000 (#/km2) | 339 |
| % Population increase from 1990 to 2000 | 21 |
| Percent pasture/hay | 42 |
| Percent cultivated crops | 14 |
| Percent forest | 23 |
| Chemistry* | |
| Nitrate (mg/L) | 3.12 |
| Ammonium (mg/L) | 0.02 |
| Total Dissolved Phosphorus (mg/L) | 0.034 |
| Soluble Reactive Phosphorus (mg/L) | 0.049 |
| Sulfate (mg/L) | 25.80 |
| Alkalinity (as mg/L CaCO3) | 56.40 |
| pH | 7.95 |
| Conductivity (μmhos) | 291 |
| Dissolved organic carbon (mg/L) | 2.72 |
| Macroinvertebrate Data | |
| years sampled | 1995-1998, 2000, 2001, 2003-2005 |
| MAIS score | 2.9 |
| 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 | Oligochaeta (aquatic worms) |
| 4th most abundant macroinvertebrate | Empididae (dance flies) |
| 5th most abundant macroinvertebrate | Ceratopogonidae (biting midges) |
*See Methods for number of years each chemistry variable was measured.