Spring Lake Habitat Rehabilitation and Enhancement Project

Rock Island District

Pool 13, Upper Mississippi River Miles 532.5 - 536.0, Carroll County, Illinois, Congressional District: Illinois - 17




Spring Lake, a 3,300-acre lake and backwater complex delimited by the natural river bank and a perimeter levee, is located on the Illinois side of the Upper Mississippi River approximately 2 miles south of Savanna, Illinois. Following World War I, the area known as Spring Lake was diked and ditched for farming. In 1938 and 1939, all project site lands were acquired in fee title by the U.S. Army Corps of Engineers as part of the 9-Foot Channel Navigation Project. Management responsibility for these lands was subsequently transferred to the U.S. Fish and Wildlife Service (USFWS). This area is now managed as a unit of the Savanna District of the Upper Mississippi River National Wildlife and Fish Refuge.

Upper and Lower Spring Lakes formerly were highly productive and heavily used sources of aquatic vegetation for migratory waterfowl. Due to breaching of the Lower Lake dike, sedimentation from river flows was degrading the aquatic habitat. Inadequate water level control capabilities and associated encroachment of woody plants and undesirable perennials were negatively affecting production of food resources preferred by migratory waterfowl in the Upper Lake. Peak waterfowl use days have decreased from 113,000 to 30,000 or less.

Project implementation is increasing the overall availability and quality of migratory bird and fish habitat at this location. Improved water level control in the Upper Lake has increased annual moist soil plant production to the benefit of dabbling ducks. Improved marsh habitat management capabilities in the Upper and Lower Lakes is providing valuable outputs to migratory waterfowl and other wetland dwelling species. The ability to distribute oxygenated water throughout the Lower Lake, while minimizing sediment access, is maintaining and enhancing this site's overall habitat value.

Quick Facts

  • Approximate Acres: 3,300 (Source: Definitive Project Report)
  • Congressional District: Illinois - 17
  • State(s) Covered: Illinois
  • Land Ownership: U.S. Army Corps of Engineers
  • Management Agency: U.S. Fish and Wildlife Service
  • Management Authority: Refuge


  • 7.1 miles of existing perimeter levee improved
  • Upper Lake subdivided into three independent management cells by constructing 7,200 feet of low elevation levees, excavating feeder channels, modifying the existing cross dike, and installing a 5,600-gpm 2-way pump station and three stop log structures
  •  Two water control structures installed in the Lower Lake levee
  • A 108-acre hemimarsh developed in the Lower Lake  (6,100 feet of low elevation levee, a 1,000-gpm well, and one stop log structure)


  • The Definite Project Report was completed in 1993
  • Formal dedication of the project was held on July 16, 1999
  • Construction was initiated in 1995, and completed in 2003
  • The Operation and Maintenance Manual was completed in 2003
  • Performance monitoring is continuing with an initial report expected in 2004.