Garden City and into Dearborn Heights where it merges with the main branch near the southern boundary with Dearborn. Other municipalities that are part of the middle branch watershed are Canton Township, Commerce Township, Farmington, Farmington Hills, Lyon Township, Redford Township, and Wixom. Tributaries of the middle branch include (from downriver to upriver) Bill's Drain Red Run Drain Wilson Drain Tonquish Creek Willow Creek Johnson Drain Walled Lake branch Thornton Creek Ingersol Creek Bishop Creek Lower branch The lower branch rises in sections 11 and 12 in Superior Township in Washtenaw County and flows mostly eastward into Wayne County through Canton Township, Wayne, Westland, Inkster, Dearborn Heights and Dearborn before joining the main branch. Other communities in the lower branch watershed include Van Buren Township, Plymouth Township, Salem Township, Ypsilanti Township. Tributaries include (from downriver to upriver): Hunter Drain Hannan Drain Fellows Creek McKinstry Drain Sinds Drain Fowler Creek Parks Drain Area of Concern The U.S.-Canada Great Lakes Water Quality Agreement defines an Area of Concern (AOC) as “geographic areas designated by the Parties where significant impairment of beneficial uses has occurred as a result of human activities at a local level.” The EPA and other environmental agencies are working to restore the 27 remaining U.S. AOCs in the Great Lakes Basin Region, including River Rouge. There are 43 AOCs in the Great Lakes Basin total, with the rest in Canada or shared by the two countries. River Rouge as an AOC Over 50% of the land surrounding the River Rouge is used for residential, industrial, and commercial purposes and development pressure continues to increase. Consequently, the river is highly polluted and was designated as a Great Lakes Area of Concern under the Great Lakes Water Quality Agreement in 1987. The designated AOC covers the entire River Rouge watershed including 48 communities that drain 466 square miles of southeastern Michigan into the Detroit River. Sources of pollution include municipal and industrial discharges, sewer overflows, and several nonpoint source pollution (e.g., storm water runoff). These activities contaminated river sediments and water with polychlorinated biphenyls (PCBs), heavy metals (e.g., mercury), polycyclic aromatic hydrocarbons (PAHs), oil and grease. These contaminants are known to be harmful to fish and wildlife and affect recreational activities. A 2008 remedial action plan for the AOC identified nine “beneficial use impairments” associated with the pollution: Restrictions on fish and wildlife consumption, due to harmful PCBs, PAHs, and heavy