Agenda - Parks and Recreation Commission - 05/08/2003

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restored to a Type 1, wet prairie wetland. A 0.77-acre riparian buffer will be incorporated along the wetland transition zone in this area. Drainage Area 7 will include a 2.30-acre stormwater detention pond. This pond will include a shallow bench that will support a fringe of emergent vegetation. Since th/s- pond will provide pretreatment of stormwater that will benefit the wetland immediately dowrmtream of it (within Drainage Area 8), it is proposed for public value wetland credits. Drainage Area 8 includes 1..35 acres of wetland and 1.55 acres of PVC buffer with a meandering channel flowing though it. Portions oft. he basin will be designed to establish Type I, wet meadow/wet prairie wetland hydrology. The basin will be established with respect to groundwater levels' and a low weir will be installed in front of the outlet such that in.filtration will be maintained, but water will be retained at a fi-equency to facilitate saturation of soils. Finer soils, could be mixed in'to promote Type 1 vegetation. Within Drainage Area 10, and along the north boundary of the RTC site, is a 3.79 acre wetland, where 2.23 acres of this wetland is within the RTC site and is denoted as "Wetland D". This wetland is a Iow'quality reed canary grass monotype with a few small areas of mixed emergent marsh vegetation. A total of 3.79 acres of wetland restoration and buffer PVC is proposed for this wetland. The pr/mary objective of this restoration would be to remove the non-native reed canary grass and reestablish.a ~tiverse, wetland community of wet meadow and mixed emergent marsh. Since portions of fi-tis 3.79-acre wetland occur on private property, landowner cooperation would be necessary to successfully restore th/s wetland. The 3.79 acres of proposed restoration includes both wetland restoration and establishment of buffers. Drainage Area 78 will include a 3.5-acre stormwater pond that will funct/on much the same as the stormwater pond proposed for Drainage Area 7. The concept design described for Area 7 generally applies to Area 18. The wetland system in Drainage Area ]9 w/]l function in a way similar to Drainage Area 8; that is, it will include a narrow, meandering, perennial strean2 with a wet meadow/wet prairie fringe. The design concept described for Drainage Area 8 describes this wetland. A total of 1.3 acres of wetland and 1.3 acres of buffer are proposed for Dra/nage Area 19. Drainage Area 24: This drainage area encompasses a linear area between the Railroad ROW and the RTC. This entire strip ofland encompasses some 10..8-acres of land. A total of 2.7-acres, or 1/4 of Area 24, is proposed as new wetland credit. A central, meandering drainage-way of Type 3 wetland is proposed. The edges of this wetland will be bordered with Type 1 and 2 wetland meadow. Drainage Area 26: Development of this combined wetland/infiltration system is conditioned on approval by Anoka County. This system would receive flows from Drainage Area 25 and would include a wetland treatment/stormwater pond (26a). From tlzis initial pond, flows would outlet into an infiltration pond/wetland system (26b), A