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WatUnd Replacement and Enhincement - It is anticipated that wetland alteration (i.e., grading for the <br />stormwater pond) will require on-site replacement Due to the poor quality of the existing wetland <br />(especially the western portion), there are opportunities to provide a net improvement in the ecological <br />health of this habitat and enhance its aesthetics. Thesouthmportionofthesite wetland is situated just <br />north of Watertown Road. Enhancing this location would provide an attractive amenity for the <br />development to be enjoyed by both residents and passers-by. Our recommendations for wetland <br />replaconent and enhancement include: <br />• Provide wetland replacement in the old field areajusteart and/or north ofthe existing stand of <br />blackwillows. Th^ already low-lying areas are adjacent to the existing wetland and could be <br />converted to wetland with minimal grading. The wetland replacement design could allow fmr <br />relativdy flat slopes to provide gradual transition zones for a variety of vretland and upiand <br />plants. Replacernent wetland areas should be seeded and planted with appropriate, lo^ ecotype <br />rutive vegetation (e.g., fox sedge, river bulrush, marsh milkweed, golden Alexanders, New <br />England aster, wool grass, iris). Care will need to be taken to prevent invasion of reed canary <br />grass into the rqilacement area. <br />• Remove all non-native vegetation (e.g., mostly reed canary grass). This should be done using <br />appropriate metbods (e.g., using an aquatic-approved berbicide, such as Rodeo). <br />• Seed and/or plant areas where teed canary grass was removed with appropriate, local ecotype <br />native v^etation. <br />Vegetated Buffer * Vegetated buffets can provide many ecological and aesthetic benefits <br />including stomiwnter management, wildlife habitat, and visual screening. Generally, the wider the buffer, <br />dw greater the benefits. Buffers ate particularly important around wetlands for water quality protection. <br />Vegetated buffers should be established by removing non-native or invuive plant qiecies and re-planting <br />with appropriate, local ecotype perennial native qtecies. Selecting the appropriate species depend on the <br />soil, moisture r^ime, smount of sunlight, adjacent vegetation, and aesthetic desires. <br />Stormwate r MiMpemewt. Bcologicaily sound stormwater management is important to protect the <br />existing on-tdte wethmd as well as downstream receiving watan, including Stubbs Bay of Lake <br />Minnetonka. Protection of aquatic resources often requires techniques beyond or in place of standard <br />curb and gutter collection syteems and stormwater poods. The profNMed plan provida for the new <br />roadway and atetmwater pqies to convey runoff into a treatment p^ partially located in the willow stand <br />ofthe existing wetland. Reooituneodations fin stormwater maruigenient include: <br />• Minimize impervious surfaces throu^XNtt foe development This can be accomplished by usitig <br />narrower streets and limiting roof, driveway, and othCT hard surface areas on individual lots. <br />• Employ rain gardens or other types of infU^onsysterm where appropriate. This requires a <br />source of water and slopes that allow fin gravity flow of runoff into mana^ment areas. <br />Management areas preferably have upland soils whh higher infiltration rates. These types of soils <br />exist on the site. Rain gatdeiu can be located and designed to intercept and manage runoff fiom <br />individual lots, reducing the capacity required by other stormwater marugrtnent areas on the site. <br />This approach can result in not only a smaller pond, but more effective and mote natural <br />stormwater managonent, which can greatly benefit aquatic resources both on site and <br />downstream. <br />• EataMifo permanent native vegetation in foe proposed rear-lot swales. While grassed swales <br />provide conveyance of runoff, native vegetation in these swales would also provide greater <br />opportunity for runoff infihration, reducing the amount of water that may rrach the stormwater <br />pond. <br />• As mentioned previously, place the stormwater management pond along foe western edge ofthe <br />southern wetland area. This would reduce forest irtgracts as well as avoid impacts to the slightly <br />more diverse portkms of the wetland. <br />te«29:iilHS 4ofS KhcKiimHtl <br />WFl.—« WVMTM ■<».dS