Lake Decatur’s water comes from a watershed (or drainage area) that is 925 square miles in size and includes parts of 7 counties in east central Illinois. In order to preserve the recently completed $92 million Lake Decatur dredging project investment and improve the lake’s water quality, in February 2020, the Decatur City Council authorized that a comprehensive long term watershed management plan be created. Northwater Consulting of Springfield, Illinois was selected to complete the plan. Documents posted here provide more information about the plan.
2021 Sequencing Map for Lake Decatur Subwatershed Planning added 3/10/2021