The Frankenmuth Dam, originally constructed in the 1850's, prevented the upstream passage of fish and separated Saginaw Bay fish from valuable spawning habitat. Species of particular interest to the Michigan Department of Natural Resources (MDNR) include walleye and lake sturgeon. In lieu of the dam, the project included construction of a rock ramp structure to provide an approximate 3% grade through this stretch of the Cass River, allowing passage of the target species upstream.