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STREAMWATCH 2005

As in previous years, the water quality assessment for the White Clay Creek was done by sampling and identifying aquatic insects (macroinvertebrates). Samples from fifteen sites on the White Clay Creek were collected on March 20, 2005. Over the summer, student interns identified, classified, and counted the invertebrates from each site. The data was processed to calculate MAIS (Macroinvertebrate Aggregated Index for Streams) ratings for each site. The students presented their results at a public meeting held at Stroud on August 9th.

The 2005 Summer Interns at Stroud

The 2005 Summer Interns were: Michael Broomall, Millersville University; Margaret Christie, Cedar Crest College; Tanya Dapkey, West Chester University; Erika Farris, University of Delaware; Buddy Kondikoff, Millersville University; Stacy Lathrop, West Chester University; Chelsea Lucas, University of Maine; William Reese, Lock Haven University; Drew Sieg, Richmond University; Holly Wielebinski, West Chester University; and Jennifer Wolf, Sweet Briar College.

On collection day, acquatic insects from each of the sampling sites were collected and bottled. Physical measurements of rocks at the sampling site were taken to enable the calculation of the area that the insects had occupied on the stream bottom. The labwork over the summer consisted of identifying and counting each of the thousands of collected insects and calculating the density of various families of insects per square meter for each site. This data was used to compute the MAIS score for each site.

The MAIS (Macroinvertebrate Aggregated Index for Streams) ratings for sites along the White Clay Creek (click here for map of White Clay Creek showing sampling station locations). Note that generally water quality deteriorates as you go downstream on each branch.

The above graph of gives some idea of what is happening at each sampling site. The black bars show the densities for EPTs - ephemeroptera (commonly, mayflies), plecoptera (stoneflies), and tricoptera (caddisflies). These insects are very sensitive to pollution and decline dramatically as you go downstream. The gray bars show the densities for non-EPTs. Non-EPTs are either insensitive to pollution or else thrive on it - for example worms and chironomidae (midges).

Regional Sites ordered by MAIS score

Scientists at Stroud have been doing similar macro invertebrates studies at other sites in the region outside the White Clay watershed. They selected several similar sites (similar with respect to urban/rural character and agricultural usage) and then merged the MAIS data from those sites in with the White Clay data to produce the above chart. It was discouraging to note that generally the White Clay sites compared very poorly with these other sites. This indicates that there is much that can be done within the White Clay watershed to improve water quality, and that development and agriculture do not necessarily have to adversely affect water quality as much as it has in the White Clay Creek.

This year Streamwatch paid particular attention to Trout Run near Avondale. The immediate area has long been a concern for Streamwatch. Site 12 is located just above Avondale, and Site 18 just below. Between the two sites are the Avondale Sewage Treatment Plant and Trout Run, and Streamwatch data has always shown a marked drop in water quality between these two sites. This year, for the first time, three samples were taken at various points in Trout Run itself. Dr. John Jackson of Stroud stated that these sites were some of the worst he has ever seen. It is not known exactly what is causing the problems, but the Trout Run watershed has been home to several mushroom operations for many decades. Careless pesticide handling, either now or long ago, may prove to be the culprit, but other explanations have not been ruled out.

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