The River Rouge is a 127-mile (204 kilometer) river in the Metro Detroit area of southeastern Michigan. It flows into the Detroit River at Zug Island, which is the boundary between the cities of River Rouge and Detroit. The river's roughly watershed includes all or parts of 48 municipalities, with a total population of more than 1.35 million, and it drains a large portion of central and northwest Wayne County, as well as much of southern Oakland County and a small area in eastern Washtenaw County. Nearly the entire drainage basin is in urban and suburban areas, with areas of intensive residential and industrial development. Still, more than of the River Rouge flow through public lands, making it one of the most accessible rivers in the state. Until recently the river was heavily polluted, and in 1969 oil on the surface caught fire. The passage of the Clean Water Act in 1972 made it unlawful to discharge any pollution from a point source into navigable waters, and the EPA's National Pollution Discharge Elimination Program was created to regulate these discharges. In 1986, a non-profit organization of concerned citizens called Friends of the Rouge was formed and began organizing an annual cleanup called Rouge Rescue, to raise awareness about the need to clean up the Rouge. In 1987, the entire watershed was designated a Great Lakes "area of concern" under the Great Lakes Water Quality Agreement. In 1992, a massive project called the Rouge River National Wet Weather Demonstration Project was implemented, and further cleanup measures are ongoing. The Alliance of Rouge Communities is an organization of governmental and non-governmental entities created in 2006 to manage the watershed. Physical and natural aspects The River Rouge totals in length and is divided into four branches, the main, upper, middle, and lower branches. The upper branch flows into the main branch in northwest Detroit, just east of Redford Township. The middle branch enters the main branch in Dearborn Heights just north of the boundary with Dearborn. The lower branch joins less than two miles (3 km) downstream in Dearborn. The lower of the river south of Michigan Avenue were channelized, widened, and dredged to allow freighter access to Ford's River Rouge Plant inland factory facilities. The plant was built between 1915 and 1927. It was the first manufacturing facility for automobiles that included within the plant virtually everything needed to produce the cars: