PHABSIM analysis of a straight trapezoidal reach and a highly sinuous reach in a low-order agricultural stream in the midwest

¹ 1668 Capistrano Avenue, Berkeley, CA 94707
² 3230b NCEL, 205 North Matthews, Urbana, IL 61801

Abstract

The PHABSIM model was applied to adjacent straight trapezoidal and highly sinuous reaches in a third order agricultural stream in East-Central Illinois. A 30-year flow record was used to generate weighted usable area (WUA) estimates for six warmwater fish species for each reach. Supplementing PHABSIM analysis, detailed surveys provided planametric maps of each reach, and regular fish sampling both supported the selection of species modeled with PHABSIM and provided data for PHABSIM evaluation. Analysis of the 30-year WUA estimates supported the development of metrics for fish community analysis, and the analysis of selected fish species populations in each reach. Six monthly fish collections in each reach provided a basis for and a detailed description of the fish communities in each reach. Metrics developed for four of the six species modeled were positively related to the relative differences in numbers of fish present between the two reaches.