This report documents the results of a workshop that examined levee alternatives at Clarence Cannon National Wildlife Refuge. This refuge is located along the Mississippi River, approximately 50 miles north of St. Louis. It was purchased primarily for waterfowl maintenance. A levee providing flood protection from the Mississippi River has broken four times since the Refuge was acquired in 1965. A number of alternatives have been proposed in response to the most recent break in 1983. Long term alternatives considered at the workshop included:

Improve the existing levee by raising the height approximately 2 ft.

Improve the existing levee by raising the height approximately 2 ft.

Maintain the levee at a lower elevation by including a spillway about 3 ft lower than the existing levee height.

Do not maintain a levee so that the Refuge will flood directly with river stage.

Repair of the major breaks in the levee, but not the more general wave damage, was considered as a short term alternative.

Participants first specified the habitats and management controls desired at Clarence Cannon National Wildlife Refuge. These were centered around attaining the maximum feasible development and management of moist soil units. Levee alternatives were evaluated in terms of their ability to provide the desired habitats and management controls. Preliminary cost estimates were prepared for each alternative, and the qualitative consequences of each alternative identified for the full set of outputs from the Refuge Master Plan.

The alternative of improving the existing levee by raising the height was unanimously preferred on purely “biological” grounds (with cost not considered). Repairing the levee with no change in elevation was unanimously selected as the most cost effective alternative.