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Title: Upper Mississippi River System Environmental Management Program Definite Project Report/Environmental Assessment (SP-21) : Small Scale Drawdown Habitat Rehabilitation and Enhancement Project, Pools 5 and 9, Upper Mississippi River, Wisconsin
Authors: United States. Army. Corps of Engineers. St. Paul District.
Keywords: Restoration ecology
Environmental protection
Environmental management
Mississippi River
Publisher: United States. Army. Corps of Engineers. St. Paul District.
Abstract: The sites considered for drawdown are located along the Mississippi River or its side channels from the lower end of pool 3 near Red Wing, Minnesota, to the middle of pool 10 near Prairie du Chien, Wisconsin. The sites are located on both sides of the navigation channel and are all less than 200 acres (80 hectares) in size. Many are in the Upper Mississippi River National Wildlife and Fish Refuge. Although the project' area is important for many species of fish and wildlife, aquatic vegetation has declined in recent years. One factor in this decline is the effect of continuous impoundment due to the navigation reservoirs. After construction of the lock and dam system, the low water levels associated with summer low river discharge and periodic droughts no longer occur because the dams maintain minimum depths for navigation. Therefore, seeds in the bottom sediments are not afforded the opportunity to germinate in order to maintain adequate aquatic vegetation for high quality fish and wildlife habitat. The ultimate goal is to preserve, restore, and enhance a backwater fish and migratory bird habitat on the Upper Mississippi River. The specific project objective is to implement a simple drawdown of a backwater area. This would allow bottom sediments to dry and consolidate, thereby, increasing the area of emergent and submerged aquatic vegetation by natural seed germination. Thirty-nine potential sites in pools 3 through 10 were submitted by the U.S. Fish and Wildlife Service and the Wisconsin, Minnesota, and Iowa Departments of Natural Resources for consideration. During the plan formulation process, the potential sites were evaluated using 23 different criteria developed by the project team based on what constituted desirable conditions for a small scale drawdown. A scoring system was also developed in order to prioritize the sites. Site visits of the highest rated sites resulted in the final selection of two sites for implementation. A habitat analysis to quantify the expected benefits of drawdowns was done for each site. The selected plan addresses the project objectives by providing a means to reduce water levels at the sites. This will allow seed germination and subsequent aquatic plant growth for a season. The plan includes the drawdown of Lizzy Pauls Pond in pool 5 near Buffalo City, Wisconsin, and Peck Lake in pool 9 at Blackhawk Park, Wisconsin. The outlet culverts at each of the sites would be closed with sandbags and electric pumps would be used to draw down the water level of the lakes at least 2 feet (0.6 meter) over a period of two to three weeks in order to dry bottom sediments. It is proposed to begin the drawdown around the end of June and maintain it until mid-September. The lakes would then be permitted to gradually refill from natural inflows. At Peck Lake, a second year of drawdown may be done, pending an evaluation of the first year results by the project biologists. Monitoring during and after the drawdown would be done to document the physical and vegetation results. The total estimated implementation cost of the project with an optional second year of drawdown at Peck Lake is $87,200. After the drawdown operation is completed, all pumps and closures would be removed and no further operation and maintenance would be required at the sites. The selected plan would positively affect 71 acres (29 hectares) of backwater habitat. The backwater habitat would be improved as a result of drying of the bottom sediments and the germination of the existing seed bank in the sediments. The growth of aquatic vegetation, especially emergent vegetation, would be enhanced for an estimated period of 10 to 15 years for improved fish and wildlife habitat. No historic properties would be affected by the proposed project. The proposed project has been coordinated with the U.S. Fish and Wildlife Service, the Wisconsin, Iowa, and Minnesota Departments of Natural Resources, the State Historic Preservation Offices, and the public. Permits and water quality certification from the Wisconsin Department of Natural Resources will not be required. An environmental assessment and Finding of No Significant Impact have been prepared in accordance with the requirements of the National Environmental Policy Act.
Description: Definite Project Report with Integrated Environmental Assessment
Rights: Approved for Public Release; Distribution is Unlimited
Size: 137 pages / 6.04 MB
Types of Materials: PDF/A
Appears in Collections:Environmental Documents

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