Illinois Benthic Macroinvertebrate Collection Method Comparison and Stream Condition Index Revision [2004: rev 2007]

A comparison of benthic macroinvertebrate collection methods was conducted for Illinois Environmental Protection Agency (IEPA) involving the hand-pick method used until 2001 and the newly instituted 20-jab multi-habitat method. IEPA collected samples in the summer of 2001 using both methods at each site and data analysis showed little dissimilarity between the methods. Using the 20-jab method in lieu of the handpick method slightly increased (2.8%) the discrimination ability of the Stream Condition Index (SCI) proposed in 2000 (Tetra Tech 2000). The SCI developed as a preliminary index, based on Illinois historical data, included only richness metrics. This report was revised in March 2007, based on the November 2004 report of the same name.