The Corps of Engineers originated during the Revolutionary War, with the Continental Congress appointing a Chief Engineer and two assistants for the Grand Army on June 16, 1775, and formally establishing the Corps of Engineers in 1779. In 1860, Major General Warren, the first St. Paul District Engineer, conducted field surveys in the Mississippi River Headwaters region, and in 1870 Congress authorized a study of whether dams and reservoirs there could help stabilize water flow in the Mississippi River between St. Paul, Minnesota, and Prairie du Chien, Wisconsin. Those studies led the St. Paul District to design a system of dams to raise water levels and store annual spring runoff in six existing lake systems for release during low water downstream that threatened navigation, and Congress funded construction and operation of the Headwaters projects between 1884 and 1912. Today the Corps maintains a 9-foot-deep navigation channel below Minneapolis, Minn., through a series of locks and dams, while the Headwaters reservoirs now serve flood control, drought storage, recreation, fish populations, and wildlife habitat. Winnibigoshish Dam, the first of the six dams built, stands on the Leech Lake Indian Reservation on the Mississippi River 170 river miles from its source in Lake Itasca and 1,244 river miles from its mouth at the Gulf Coast. The original timber-crib dam on timber piles, built at the lake outlet and completed in 1884, deteriorated and was replaced by concrete by 1903; today it is a 162-foot-long concrete structure on timber piles controlling runoff from a 1,442-square-mile drainage area that includes 28 lakes. Its original construction used about 300 skilled and unskilled workers and cost $75,000. Lake Winnibigoshish, covering 67,000 acres with 141 miles of shoreline, occupies a basin formed by a huge ice block left by a receding glacier and is surrounded by glacial deposits; archaeological sites along its shore show prehistoric settlements, and the Ojibwa named it Winnibigoshish, meaning "miserable-wretched-dirty-water," after storm winds churned up its muddy bottom.