The St. Louis District, which encompasses 28,000 square miles and is almost equally divided between Missouri and Illinois, is an engineering and water resource agency dedicated to maintaining a proper and healthy balance of the varying uses of the heartland's waterways. We support the needs of the community and the environment through many civil works missions. To fight the devastating effects of floods, 87 levees (totaling 750 miles in length) constructed to protect 575,000 acres of economic and agricultural interests in the region. To ensure the safe passage of commerce on our waterways, we also maintain a Congress-mandated nine-foot navigation channel on 300 miles of the Middle Mississippi River, 80 miles of the lower Illinois River and 36 miles of the Kaskaskia River. This is accomplished through several different types of river engineering practices, including locks and dams, which maintain a pool at a depth necessary to meet navigation requirements, while still fulfilling the needs of the environment. The St. Louis District also operates and maintains five lakes and their associated recreational areas. These lakes, which serve a variety of purposes ranging from flood protection and recreation to potable water supply and hydroelectricity, average over 15 million visitors a year. Other missions include environmental restoration, environmental river engineering (created by the St. Louis District), water supply, emergency responses to natural disasters, regulatory oversight (issuance of permits and wetland delineation), hydropower, recreation, Ordinance and Explosive Waste Program, and clean up hazardous and toxic waste material connected to Department of Energy activities in the 1940s-1960s.