Lake Erie Basin consists of Lake Erie and surrounding watersheds, which are typically named after the river, creek, or stream that provides drainage into the lake. The watersheds are located in the states of Indiana, Michigan, New York, Ohio, and Pennsylvania in the United States, and in the province of Ontario in Canada. The basin is part of the Great Lakes Basin and Saint Lawrence River Watershed, which feeds into the Atlantic Ocean. 80% of the lake's water flows in from the Detroit River, with only 9% coming from all of the remaining watersheds combined. (The remainder (11%) is derived from direct precipitation into the lake.) A littoral zone serves as the interface between land and lake, being that portion of the basin where the lake is less than 15 feet (4.6 m) in depth.[1]