Randomly chosen sites provide CTAP with a way of determining the condition of Illinois streams on the broadest possible scale. Up to 150 streams will be sampled over a five year period, with resampling taking place beginning in the sixth year. Available data indicate that basins with high human population densities or heavy agricultural development have lower EPT richness than do wooded areas.
Organic enrichment is apparent in some of the Rock River tributaries.
Riparian and in-stream habitat has been altered dramatically across the state, especially so in highly urban and in agricultural areas. CTAP is poised to describe, for the first time, the condition of streams across the state, and to measure any changes in them in the future. Comparison of historical and contemporary EPT assemblages across Illinois. Most effort recently has focused on stoneflies. A comparison of the response of two stonefly genera in the state has produced the following results.