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White Clay Watershed Association
Stream Watch - 1995 Data
The bar graphs on the this page are representative of the trends found for sites along the East and Middle branches of the WCC over the past five years. They are plotted in order, starting at the head waters for each branch and working its way downstream towards Delaware.
The graph below refers to three pollution sensitive taxonomic groups, ephemeroptera (commonly, mayflies), plecoptera (stoneflies), and tricoptera (caddisflies). The data is plotted as average density in a square meter.
The data plotted in the EPT graph indicate that there is a decline in the water quality as one proceeds through the sites from the headwaters down into Delaware. The evidence is in the progressive decrease in overall numbers of the pollution sensitive aquatic macro invertebrates as the creek flows downstream from the headwaters. Most discouraging was the condition of the sites in the preserve (EastBranchl6 and MainStreaml4), which are downstream from agricultural, residential and commercial usage.
The Species Richness graph below refers the average number of different families found at each station.
The data plotted demonstrates a decline in biodiversity, exhibited by the stepwise decrease in variety as you progress downstream. This data does not show a dramatic difference from station to station. However, when combined with the EPT data, it demonstrates a statistically significant decrease in both diversity and total numbers of pollution sensitive organisms.
Although the data generated may not paint a pretty picture with regards to the water quality of the WCC, the data is extremely useful.
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