Streamwatch Project
Middle Run and Lower Mainstem of White Clay Creek: Site 21
Site 21 on the Lower Mainstem is found at Windy Mill Park above Kirkwood Highway (a.k.a. Capitol Trail), upstream of Middle Run tributary. This is the second largest site sampled in the study. The area immediately near the sampling location is heavily developed and populated, but overall only 10% of the watershed is developed area. The increase in the percentage of forest in the watershed compare to sites in the upper watershed (e.g., Sites 3, 4, 19, 25) may be due to the presence of the White Clay Creek Preserve that borders large portions of the stream in southern PA and northern DE. Water chemistry variables examined indicated no obvious problems, but the data is limited to 3 years (1995-1997).
Similar to many sites in the Lower White Clay, chironomid midges dominated the samples. Midges made up >85% of the total density and EPT made up ≈13% of the total density (total macroinvertebrate density average 7000 individuals/m2). Total Richness averaged 6 taxa/200 individuals, with only two of those taxa being EPT. The MAIS score averaged 2.9 and rated Poor in the five years sampled. Only in 2005 did the MAIS score (5.9) approach the Fair category. A regression of MAIS and year suggest conditions are improving at this site.
| Location | |
|---|---|
| Site number | 21 |
| Description | At Windy Mill Park above Kirkwood Highway (a.k.a. Capitol Trail), upstream of Middle Run tributary |
| Lat Long (hr min sec) | 39°41.530’ N, -75°43.484’ W |
| Land Use | |
| Watershed area above site (km2) | 183 |
| Population density in 2000 (#/km2) | 192 |
| % Population increase from 1990 to 2000 | 20 |
| Percent pasture/hay | 46 |
| Percent cultivated crops | 16 |
| Percent forest | 24 |
| Chemistry* | |
| Nitrate (mg/L) | 3.37 |
| Ammonium (mg/L) | 0 |
| Total Dissolved Phosphorus (mg/L) | n/a |
| Soluble Reactive Phosphorus (mg/L) | 0.014 |
| Sulfate (mg/L) | n/a |
| Alkalinity (as mg/L CaCO3) | n/a |
| pH | 7.87 |
| Conductivity (μmhos) | 242 |
| Dissolved organic carbon (mg/L) | 2.50 |
| Macroinvertebrate Data | |
| years sampled | 1995-1998, 2000 |
| 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 | Hydroptilidae (microcaddisflies) |
| 4th most abundant macroinvertebrate | Tipulidae (crane flies) |
| 5th most abundant macroinvertebrate | Empididae (dance flies) |
*See Methods for number of years each chemistry variable was measured.