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Surface Water

Illinois has abundant surface water resources. Three large rivers form much (about 911 miles) of the state's borders: Mississippi River on the west, Wabash River on the east, and Ohio River to the south (U.S. Geological Survey 2014). About 64 miles of Lake Michigan shoreline borders the northeast. Within Illinois borders are 106,940 miles of streams. Of these "interior" streams, 25,019 miles are perennial, 78,245 miles are intermittent, and 3,676 miles are ditches or canals. Illinois also has more than 91,400 lakes and ponds of which 1,279 are publicly owned (154,333 acres).

To track environmental conditions and to evaluate the efficacy of water-pollution-control programs as required by state and federal regulations, Illinois EPA has been monitoring Illinois surface water since 1970. Monitoring and assessing environmental conditions provides vital information for achieving natural-resource goals and ensuring that Illinois waters are suitable and safe for human consumption and recreation while supporting other beneficial uses, such as supporting healthy aquatic life, contributing to aesthetic enjoyment, and providing for various agricultural and industrial uses. Offering a variety of financial, technical, and educational program assistance opportunities also serve to achieve natural-resource goals.