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integrity or quality oft. he wetland or pond. (Commentary: The sensitivity of a wetland to <br />degradation varies with the type of vegetation. Sedge meadows, open bogs and swamps, <br />coniferous bogs, calcareous fens, Iow prairies, lowland hardwood swamps, and seasonally <br />flooded basins are highly sensitive to degradation. Flood plain forests, reed canary ~ass <br />meadows, shallow (reed canary grass, cattail, giant reed or purple loosestfife) marshes are only <br />slightly sensitive to degradation. See the current version of the Minnesota Pollution Control <br />Agency's publication "Storm-Water and Wetlands: Planning and Evaluation Guidelines for <br />Addressing Potential Impacts of Urban Storm-Water and Snow-Melt Runoff on Wetlands" for <br />details.) <br /> <br /> Subdivision 4. The following storm water management practices must be investigated in <br />developing the storm water management part of the storm water pollution control plan in the <br />following descending order of preference: <br /> <br />Ao <br /> <br />Protect and preserve as much natural or vegetated area on the site as <br />possible, minimizing impervious surfaces, and directing runoff to vegetated <br />areas rather than to adjoining streets, storm sewers and ditches. <br /> <br />B. Flow attenuation of treated storm water by use of open vegetated swales and <br /> natural depressions; <br /> <br />C. Storm water wet detention facilities (including percolation facilities); and <br /> <br />A combination of successive practices may be used to achieve the applicable <br />minimum control requirements specified in subsection (A) above. The <br />applicant shall provide justification for the method selected. <br /> <br />9.27.12 Minimum Design Standards for Storm Water Wet Detention Facilities. <br />At a minimum these facilities must conform to the most current technology as reflected in the <br />current version of the Minnesota Pollution Control Agency's publication, "Protecting Water <br />Quality in Urban Areas" and the current requirements found in the same agency's NPDES <br />permits for storm water associated with construction activities. <br /> <br />9.27.13 Minimum Protection for Natural Wetlands. <br /> <br /> Subdivision 1. Runoffmust not be discharged directly into wetlands without appropriate <br />quality (e.i., treated) and quantity runoff control, depending on the individual wetland~s <br />vegetation sensitivity. See the current version of the Minnesota Pollution Control Agency's <br />publication, "Storm-Water and Wetlands: Planning and Evaluation Guidelines for Addressing <br />Potential Impacts of Urban Storm-Water and Snow-Melt Runoffon Wetlands" for guidance. <br /> <br /> Subdivision 2. Wetlands must not be drained or filled, wholly or partially, unless <br />replaced by either restoring or creating wetland areas of at least equal public value. <br />Compensating for the impact by replacing or providing substitute wetland resources or <br />environments with those of at least equal public value. Compensation, including the <br />replacement ratio and quality of replacement should be consistent with the requirements <br /> <br />Draft StormWater Ordinance <br /> <br /> Page 13 of 20 <br />98 January 20, 2006 <br /> <br /> <br />