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View detailed information about the Thornapple River Restoration Project

The Thornapple River Watershed (TRW) is a major subbasin of the Grand River Watershed, which flows into Lake Michigan. The Grand River Watershed is the second largest drainage system in the State of Michigan and comprises 13% of the entire Lake Michigan drainage basin, with a drainage area of 5,572 square miles . The TRW plan area drains approximately 700 square miles of predominately agricultural lands in the five counties of Eaton, Barry, Kent, Ionia and Allegan. The main channel of the Thornapple is 78 miles long, originating in northeastern Eaton County. The river flows in a westerly direction to the village of Middleville in northwest Barry County, at which point it flows north to its confluence with the Grand River near the town of Ada in south-central Kent County.