Abstract
Rapid Bioassessment Protocol (RBP) is a set of guidelines developed by the USEPA to standardize the practice of using qualitative survey techniques on aquatic organisms to gauge stream health. One component of RBP involves selecting a small section of a stream, known as a "representative reach", which is supposed to represent the conditions found over a larger area of the stream. This study was conducted to examine the variability between reaches in close proximity to each other, and to determine if that variability could be great enough to influence RBP results. I also looked at whether anthropogenic disturbance within the streams watershed appeared to be related to variability between reaches. Four candidate "representative reaches" were sampled in each of three separate Michigan streams with varying anthropogenic disturbance. Differences among reaches were then evaluated using three common indices: The number of Epnemcroptera, Plecoptera, Trichoptera (#EPT), the Sequential Comparison Index (SCI), and the Michigan Dept. of Environmental Quality "Procedure-51" biotic index. Results indicate little variability between reaches in streams with little impact, and much greater variability between reaches in streams impacted by development. This suggests that monitoring programs f or impacted streams may need to sample more reaches to describe conditions compared to streams with little impact.