The Mississippi River above the Minnesota River Confluence is the stretch of the river which flows between Lock and Dam 1 and the entrance of the Minnesota River in St. Paul. Minnehaha Creek flows into this section of the Mississippi River. Several parks and landmarks lie close to this stretch of the river, including Minnehaha Regional Park with Minnehaha Falls, Fort Snelling State Park with the historic Fort Snelling, and Hidden Falls Regional Park with Hidden Falls, a waterfall formed from a nested groundwater aquifer. This section of the river is part of the Mississippi National River and Recreation Area and the USACE's 9-Foot Channel Navigation Project. Monitoring in this section of the river has been limited to special studies.The Mississippi River is one of the world's largest rivers, flowing over 2,300 miles through the center of the United States. It begins at Lake Itasca in northern Minnesota and ends at the Gulf of Mexico, where pollutants carried by the river contribute to the Gulf's Dead Zone. Millions of people rely on the Mississippi River as a source of drinking water, and the river is also an important waterway for shipment of commodities. The Mississippi River watershed is the 4th largest in the world at about 1.2 million square miles. The section of the watershed in and upstream of the Twin Cities Metropolitan Area has a mix of several types of land including forests, wetlands, agriculture, and developed areas.