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Title: Upper Mississippi River System Environmental Management Program Definite Project Report/Environmental Assessment (SP-15) : Trempealeau National Wildlife Refuge Habitat Rehabilitation and Enhancement Project, Pool 6, Upper Mississippi River, Trempealeau and Buffalo Counties, 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 5,620-acre Trempealeau National Wildlife Refuge is located adjacent to the Mississippi River on the Wisconsin side at pool 6 near Trempealeau, Wisconsin. The Refuge is located in Trempealeau and Buffalo Counties. It is separated from the main channel by the Burlington Northern Railroad embankment and from the Trempealeau River by a barrier dike. About 75 percent of the Refuge is marsh, open water, and seasonally flooded areas. The remainder is bottomland hardwoods, upland forest and shrublands, and grasslands. It is possible to divide the Refuge into several separate hydrologic units or pools because of natural topography and existing dikes and railroad structures. With the exception of pool A, existing habitat conditions on the Refuge are considered to be very good. However, woody vegetation is expanding in portions of the Refuge, resulting in a gradual decline in the role of the Refuge as a major feeding and resting area for migratory birds. Pool A lacks submerged aquatic vegetation because of turbid water conditions caused by wave action and rough fish activity. Also, winter dissolved oxygen levels are not adequate to establish or maintain a desirable fishery in pool A. The ultimate goal is to preserve, restore, and enhance plant and animal habitat and to provide breeding, resting, and feeding habitat for migratory birds and marsh wildlife on the Refuge. A primary goal is to provide flexibility in controlling water levels in selected management pools during various times of the year. Specific project objectives include: establishing emergent and submergent aquatic plant growth in pool A; maintaining existing islands; establishing a winter fish refuge in pool A; and providing a flooded marsh and limiting woody plant invasion in pools C and E. The plan formulation process considered several alternatives for addressing the project objectives. This included building dikes, islands, pump stations, control structures, and providing water supplies and aeration in selected pools. The selected plan would provide the opportunity to control water levels in several areas of the Refuge in order to preserve, restore, and enhance a diversity of indigenous plant and animal communities and to provide breeding, resting, and feeding habitat for migratory birds and marsh wildlife. Fish habitat would also be improved on part of the Refuge. The selected plan of action includes creating three management pools by constructing three dikes totaling about 17,000 linear feet, three water control structures, a permanent pump station and two portable pump facilities, island stabilization, and an aeration system in one management pool. A 700-acre management pool would be created and a 22,000-gpm pump station would provide the capability to draw the pool down 2 feet to establish and promote the growth of aquatic vegetation and to manage fisheries. This pool would also be aerated at two locations during the winter to improve fish habitat. A 220-acre management pool created in another part of the Refuge would be capable of ponding up to 4 feet of water using 9,000-gpm portable pumps and an inlet from the Trempealeau River. The pool could be used for a spring resting and feeding area, brood use, or fall migration, depending on weather conditions and the type of habitat desired. A third management pool 550 acres in size would be created in the northern part of the Refuge that would be capable of providing a 2-foot increase in water level using 9,000-gpm portable pumps. The raise in water level would provide a flooded marsh for migratory birds and also limit the encroachment of woody vegetation into the pool. An estimated 220,000 cubic yards of sandfill to build the three dikes would be obtained by dredging from outside the Refuge near the main channel of the Mississippi River, from within pool A, or from a dredged material beneficial use site near Fountain City or Trempealeau, Wisconsin. The total direct construction cost of the project is estimated to be $4,649,000. Indirect costs for planning, engineering, and design efforts and construction supervision and administration bring the total project cost to $5,388,000. Average annual operation and maintenance costs of the project are estimated to be $21,700 and would be the responsibility of the U.S. Fish and Wildlife Service. The selected plan would improve migratory bird habitat conditions on 3,470 acres of the Refuge. Of these acres, 700 acres in pool A would also have improved fish habitat conditions. These habitat conditions would be improved as a result of the ability to directly manage water levels in 1,470 acres of the Refuge and maintain existing water level conditions in 2,000 acres of the Refuge. Dissolved oxygen levels would be improved in the 700-acre pool A by aeration. Reducing the number and biomass of rough fish and stocking with fish such as largemouth bass, black crappie, and bluegill would improve the fishery. Dredging for topsoil would provide about 2 acres of additional deepwater fish habitrt for such species as bluegill and largemouth bass. Erosion at two existing islands would be reduced by protecting the shoreline with rockfill (Kiep's Island) or by reducing the wind fetch (Black Oak Island). Cultural artifacts on the shoreline of Kiep's Island would be protected by rockfill. The dikes would provide about 13 acres of terrestrial habitat for waterfowl and animals. Increased aquatic vegetation would provide habitat for aquatic furbearers and waterfowl. No archaeological or historical sites listed on the National Register would be affected by the proposed project. However, sites deemed eligible or with a high probability of eligibility for inclusion on the National Register would be affected by haul or access routes for construction equipment.
Description: Definite Project Report with Integrated Environmental Assessment
Rights: Approved for Public Release; Distribution is Unlimited
Size: 404 pages / 29.1 MB
Types of Materials: PDF/A
Appears in Collections:Environmental Documents

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