Swan Lake Habitat Rehabilitation and Enhancement Project

St. Louis District

Pool 26, Upper Mississippi River, Miles 5 - 13.5, Calhoun County, Missouri, Congressional District: Illinois 13

Partners

• US Fish and Wildlife Service
• Illinois Department of Natural Resources 

Description

The Swan Lake HREP is located in in Calhoun County, Illinois, on the right descending bank of the Illinois River, between river miles 13.3 and 5.0. The project is operated by the U.S. Fish and Wildlife Service and the Illinois Department of Natural Resources.   The project is located in the Calhoun Division of the Two Rivers National Wildlife Refuge and the Illinois Department of Natural Resources Fuller Lake Management Area.

Swan Lake is bottomland lake approximately 2,900 acres in size with an average depth between 3 and 3.5 feet.  This water body constitutes a significant portion of the backwater habitat in the Upper Mississippi River Valley and the Illinois River.  This is the largest backwater complex in Pool 26 of the Mississippi River and one of the largest on the Illinois River.  Bottomland lake habitat such as Swan Lake has significantly declined over the last century and the remaining backwater lakes are severely degraded due to sedimentation and altered hydrology for navigation and flood control.  With the construction of Lock and Dam 26, water levels in the lower Illinois River were raised and stabilized.  This also raised the water levels in Swan Lake, resulting in permanent inundation of a much larger area.  The bottomland hardwoods adapted for wet-dry cycles were lost due to the prolonged flooding, and the sluggish backwater habitat quickly filled with sediment resulting in increased turbidity eradicating the aquatic vegetation.

The specific goals as stated in Definite Project Report (DPR) were to: 1) Restore aquatic macrophyte beds and associated invertebrate communities for the benefit of migratory waterfowl;  2) Provide habitat for over winter survival of fish;  3) Provide habitat for spawning and rearing of fish;  and, 4) Increase the overall habitat value for waterfowl and fishes. In order to achieve these goals, sedimentation, lack of water level control, and wind fetch at the site needed to be addressed.

Quick Facts

• Approximate Acres: 2900
• Congressional District: Illinois 13
• State(s) Covered: Illinois
• Land Ownership: State of Illinois and Federal
• Management Agency: ILDNR and USFWS
• Management Authority: Cooperative Agreement

Project Features

• Construction of a 8.8-mile long riverside levee/dike to reduce river-borne sedimentation
• Dredging to provide deep water fish habitat
• An interior lake closure was constructed to subdivide the lower portion of Swan Lake into two independently managed, but complimentary habitat compartments, and serve as a wind barrier.Construct a riverside dike/levee structure to retard the deposition of river induced sediment.
• Closure/fish passage stop-log structures were constructed at the southern end of Lower Swan Lake (river mile 5.0) and at the upper end of Middle Swan Lake (river mile 9.8) to separate Swan Lake from the Illinois River while still allowing for fish passage. 
• Gravity flow sluice-gated culverts, stop-log structures, corrugated metal pipe, and pumps were installed to perform and control watering and dewatering of the Swan Lake compartments as management objectives dictate.
• Erosion control practices were implemented at more than forty sites in the Swan Lake Watershed by the end of 1998.  This included 25 water and sediment control basins (WASCOB) in upland watersheds to reduce sediment transported by tributaries flowing into the lake.
• Boat access areas were created/enhanced to mitigate for project impacts to existing site access areas.
• Island groups were constructed to serve as barriers to reduce turbidity from wind generated wave action.

Milestones

• The Definite Project Report was completed in January 1993.
• Construction was completed in July 2001.
• Chief of Engineers Design and Environmental Awards winner, 2004.
• A Performance Evaluation Report was completed in August 2010.
• The OMRR&R Manual was completed in 2014