11/28/2001 Env Bd Packet - Laserfiche WebLink

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GENERAL DESIGN CONSIDERATIONS FOR WILDLIFE POND CONSTRUCTION AND WETLAND ALTERATIONS The Rice Creek Watershed District has reviewed information from the U.S. Army Corps of Engineers and the Minnesota Department of Natural Resources on the design and construction of wildlife ponds. The RCWD recommends that the following considerations be incorporated. to the greatest possible extent, when constructing wildlife ponds or working within wetland areas. SIZE: The wildlife pond should be at least 1/4 acre in surface area size, although larger ponds (up to 1 acre) are preferred. SHORELINE CONTOUR It is recommended that a variable (rather than an even- sided) shoreline be constructed. This will increase the amount of shoreline per unit area thereby creating isolated areas conducive for waterfowl usage. BOTTOM CONTOUR: The bottom contour' should be varied to promote the growth of emergent vegetation. A 50'0 open water and 50% vegetative cover (including the emergent vegetation around the shoreline) will provide the greatest diversity of wildlife species. Water depth should be about 12 to 18 inches in the shallow area or the basin and about 3 to 4 feet maximum in the deepest areas.. SIDE SLOPES: The upland side slopes towards the pond should range from 3:1 to 10:1. The pond bottom side slope should be 8:1 to 12:1. BUFFER ZONE: It is important to re- establish and maintain an upland vegetative buffer ;one around the perimeter of the wildlife pond to provide nesting habitat and filter runoff. Mowing of upland areas should be avoided, if possible, until August 1 to protect nesting areas and allow for brood dispersal. BOTTOM MATERIAL: If possible, topsoil should be placed on the bottom of the basin to provide a more suitable base for aquatic vegetative growth. In addition, "muck" from an existing wetland should • be added to the topsoil, providing a "seed" for a beneficial biological aquatic community to be established. DREDGED SPOILS: All dredged spoils from pond excavation activity will need to be placed above the existing 100 -year flood elevation for the site. Erosion control measures such as silt fences and/or staked hay bales will need to be provided around the spoils. The spoils should be placed within a diked upland area to allow the spoils to dewater into the soil. Io,i