Pool 24 Islands Habitat Rehabilitation and Enhancement Project                                                                 

St. Louis District

Partners

• US Fish and Wildlife Service
• Missouri Department of Conservation 

Description

The proposed project includes Gilbert, Blackbird, North Fritz, and South Fritz Islands in Pike and Ralls counties, Missouri.  The islands are in Mississippi River Pool 24 between river miles 286 and 299.5 near Ashburn, Missouri.  These islands are General Plan lands owned by the Corps of Engineers and are managed by the Missouri Department of Conservation through a cooperative agreement with the US Fish and Wildlife Service.

The land cover on the four islands is predominantly floodplain forest with interspersed former agricultural fields.  Cottonwoods and maples are the dominant tree species with occasional sycamores and pecans.  The former agricultural fields are in various stages of succession.  Each island has at least one interior side channel.  These channels have frequent fallen trees, are shallow, and lack depth diversity.

There is a need for restoration of the Pool 24 Islands to prevent further degradation of these habitats.  Sedimentation in the side channels continues to reduce their depth.  Lack of an adequate influx of seeds and strong competition prevents bottomland hardwood establishment resulting in low forest diversity.  Small islands within Gilbert Island's western side channel are eroding and will eventually disappear.  Without restoration, side channel conditions will continue to deteriorate, erosion will continue, and bottomland hardwood establishment will be impaired.  These factors combine to adversely affect the fish and wildlife resources along this reach of the Mississippi River.

The objectives of this proposed project include: 1) Restore and enhance secondary channel depth, flow, and aquatic habitat; 2) Improve floodplain forest diversity; and 3) Reduce island erosion

Quick Facts

• Approximate Acres: 3150
• Congressional District: Missouri - 6
• State(s) Covered: Missouri
• Land Ownership: U.S. Army Corps of Engineers
• Management Agency: Missouri Department of Conservation
• Management Authority: Cooperative Agreement

Proposed Potential Features

• Dredging of interior channels on all four islands to restore depth and provide deep aquatic habitat.
• Use of dredged material to build low elevation ridges within the interior of each islands which will then be planted with bottomland hardwood trees
• Installation of river training structures along the banks in the interior channels of all four islands to create habitat diversity, flow sinuosity, and deep holes for fish habitat.
• Construct a submerged closing structure in the upstream end of each interior channel to reduce influx of heavy sediments and create a deep hole for fish habitat.
• Notch the upstream end of the submerged closing structure in the Gilbert Island Western Side Channel to increase flow.
• Construct 5 hard point structures or chevrons within the Gilbert Island Western Side Channel to increase flow and depth diversity.
• Placement of bullnose type structure at head of each small island within the Gilbert Island Western Side Channel.

Milestones

• Fact Sheet Approved, 2009 
• This project has been deferred