Agenda Packets - 2021/07/06 - Laserfiche WebLink

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Page 2 - 6/200 - Oak Lake Park Addition - Has low bulk density, is very compressible, and is susceptible to frost action. - Depth of organic material is generally 3 feet or less. Udorthents, wet substratum is made up of heterogeneous, earthy fill material that has been placed on poorly drained and very poorly drained mineral and organic soils. The thickness of the fill is variable as is the source of the material. The areas indicated for development within the project consist mostly of Zimmerman loamy fine sand, 0 to 6% slopes and Urban land - Zimnerman complex, 1 to 87. slopes. These soils are well suited to building site development. Because these soils erode easily, erosion control, espe- cially during and immediately following construction, is desirable. 2. Erosion and siltation hazard as a result of change. During and immediately after construction erosion is a hazard if proper cover is not maintained. The surface soil should be stripped and re- turned after construction to allow for easier revegetation. Where sandy soil material is exposed on pond side slopes, a topdressing of loamy soil material should be worked into the top 4-6 inches of soil. Revegetation can be accomplished with sod or by seeding. Where seed is used, clean hay or straw mulch should be applied at the rate of 2500 to 3500 lbs/acre. Mulch should be anchored with netting material or by driving over it with a straight set blunt disk. Sediment from street sanding operations will most likely enter the wetland, but a storm drainage plan was not available to determine this. Regular scheduled maintenance excavation @ storm sewer outlets should be considered. 3. Nutrient and pollutant hazard as a result of change. At present, the wetland has considerable nutrient assimilative capacity. If the wetland is converted into open water much of this assimilative capacity will be lost. Nutrient input to the pond will increase due to the proposed development. Efforts should be made to retain as much emergent wetland vegetation as possible. This can be accomplished through more gradual side slopes or by "stepping" side slopes to provide more shallow water areas during periods of normal water elevation. 4. Will change improve appearance of the affected area? A mutter of personal preference concerning emergent wetland vegetation vs. open water. 5. Other characteristics An ice -clogged outlet in late winter or early spring combined with increased runoff from impervious areas could accentuate flooding in the pond area.