Changes Over Time
Within each site, water quality varied over time but there were no trends indicating sites have improved or become more degraded since 1991.
Only Site 7 below the Middle and West Branches and Site 21 on the Lower Mainstem show signs of possible improvement.
MAIS scores for Site 7 below the West and Middle Branches and Site 21 on the Lower Mainstem suggest water quality may be improving at these locations.
Long-term datasets from USGS suggest that water quality in the upper WCC has gotten better since 1972. The trend of improved water conditions was also observed for some long-term sites in the Schuylkill watershed.
Comparison of USGS long-term data for WCC and sites considered some of the best in the Schuylkill watershed indicated conditions in the East Branch of WCC and Valley Creek, are not as good as those in French and Pickering Creeks. Presently, sites on the upper WCC are comparable to conditions observed on French and Pickering Creeks in the 1970’s and 80’s.
Overall results suggest water quality in WCC has improved significantly since 1972, but that since 1994 the change, if any, is occurring at a less dramatic rate.
USGS data for four sites in WCC (USGS 28, 29, 30 and 58) and three sites in the Schuylkill watershed; French (USGS 15), Pickering (USGS 5), and Valley (USGS 50/52). Richness measures are based on number of families/200 individuals. Sensitive richness was based on families whose tolerance value ≤5. Collection method was initially Lium but changed to Hess in 1998.