Biological and habitat assessment of the Lower Rouge River, Michigan 2018

A key component of evaluating the success of habitat remediation projects is determining preremediation conditions, biotic and abiotic, to establish a baseline and compare with postproject conditions. The Rouge River, Michigan, is a Great Lakes Area of Concern with a listed Beneficial Use Impairment related to loss of fish and wildlife habitat. A biological and habitat assessment was completed in the lower Rouge River, focused along a nearly 7-kilometer stretch of river that includes a concrete channel anticipated to be removed by 2022, to determine prerestoration conditions. Surveys documented the presence and quality of physical habitat, presence of herpetofauna, and quantified macroinvertebrate and fish assemblages at 12 sites (3 upstream from the concrete channel, 6 within the concrete channel, and 3 downstream from the concrete channel). Macroinvertebrate assemblages were dominated by Chironomidae and Oligochaeta for June and September. The electrofishing catch per unit effort was driven by Notropis atherinoides (emerald shiner) catches in June and emerald shiner and Dorosoma cepedianum (gizzard shad) catches in September. Graptemys geographica (northern map turtle) was the most common reptile observed throughout the lower Rouge River. No submergent macrophytes were discovered, and riparian vegetation was sparse in the concrete channel section. No sites scored “excellent” (total score greater than 154), upstream control sites scored “good” for overall qualitative habitat assessments (total score 105–154), and all concrete channel and downstream control sites were ranked as “marginal” (total score 56–104) or “poor” habitat (total score 0–55). Results from this assessment can be used to compare with postremediation projects in the lower Rouge River.