2022-09-13 P & Z Packet - Laserfiche WebLink

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ii. In an ERA within a DWSMA classified as moderate vulnerability unless a higher level of engineering review sufficient to provide a functioning treatment system and to prevent adverse impacts to groundwater has been approved by the \[NAME OF MS4\]; or iii. Outside of an ERA within a DWSMA classified as having high or very high vulnerability unless a higher level of engineering review sufficient to provide a functioning treatment system and to prevent adverse impacts to groundwater has been approved by the \[NAME OF MS4\]. g) Areas within 1,000 feet upgradient or 100 feet downgradient of active karst features; and h) Areas that receive runoff from the following industrial facilities not authorized to infiltrate stormwater under the NPDES stormwater permit for industrial activities: i. automobile salvage yards; ii. scrap recycling and waste recycling facilities; iii. hazardous waste treatment, storage, or disposal facilities; iv. wood preserving facilities; or i.v. air transportation facilities that conduct deicing activities. ( ) where industrial facilities are not authorized to infiltrate industrial stormwater under an NPDES/SDS Permit, ( ) where vehicle fueling and maintenance occur ( ) with less than 3 feet of separation from the bottom of the infiltration system to the elevation of the seasonally saturated soils or top of bedrock ( ) where high levels of contaminants in soil or groundwater will be mobilized by the infiltration of stormwater. 0) Infiltration techniques will be restricted when the infiltration device will be constructed in areas: ( ) with predominately Hydrologic Soil Group D soils ( ) within 1,000 feet up-gradient or 100 feet down-gradient of active karst features ( ) within a Drinking Water Source Management Area (DWSMA) as defined in the cities Wellhead Protection Plan ( )where soil infiltration rates are more than 8.3 inches per hour B) If volume and pollutant management controls cannot be constructed on-site, off-site locations where the controls can be met must be identified. Guidance for best management practices and standards for these mitigation processes should follow the Minimal Impact Design Standards (MIDS) Design Sequence Flowchart for flexible treatment options contained in the MN Stormwater Manual. 1) For non-linear projects, where the water quality volume cannot cost effectively be treated on the site of the original construction activity, the remaining water quality volume must be addressed through off-site treatment and meet the following requirements (must be selected in the following order of preference): (a) Locations that yield benefits to the same receiving water that receives runoff from the original construction activity. 420 |Page