12-14-2022 Council Packet - Laserfiche WebLink

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(c) Where soil infiltration rates are more than 8.3 inches per hour unless soils are amended to slow the infiltration rate below 8.3 inches per hour. (d) With less than three (3) feet of separation distance from the bottom of the infiltration system to the elevation of the seasonally saturated soils or the top of bedrock. (e) Of predominantly Hydrologic Soil Group D (clay) soils. (f) In an Emergency Response Area (ERA) within a Drinking Water Supply Management Area (DWSMA) as defined in Minn. R. 4720.5100, Subp. 13, classified as high or very high vulnerability as defined by the Minnesota Department of Health. (g) In an ERA within a DWSMA classified as moderate vulnerability unless you perform or approve a higher level of engineering review sufficient to provide a functioning treatment system and to prevent adverse impacts to groundwater. (h) Outside of an ERA within a DWSMA classified as high or very high vulnerability unless you perform or approve a higher level of engineering review sufficient to provide a functioning treatment system and to prevent adverse impacts to groundwater. (i) Within 1,000 feet up-gradient or 100 feet down-gradient of active Karst features. (j) That receive stormwater runoff from these types of entities regulated under NPDES for industrial stormwater: automobile salvage yards; scrap recycling and waste recycling facilities; hazardous waste treatment, storage, or disposal facilities; or air transportation facilities that conduct deicing activities. 4. For non-linear projects, where the water quality volume cannot cost effectively be treated on the site of the original construction activity, you must identify, or may require owners of the construction activity to identify, locations where off-site treatment projects can be completed. If the entire water quality volume is not addressed on the site of the original construction activity, the remaining water quality volume must be addressed through off- site treatment and, at a minimum, ensure the below requirements are met: (1) You must ensure off-site treatment project areas are 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. (b) Locations within the same DNR catchment area as the original construction activity. (c) Locations in the next adjacent DNR catchment area up-stream. (d) Locations anywhere within Little Canada. (2) Off-site treatment projects must involve the creation of new structural stormwater BMPs of the retrofit of existing structural stormwater BMPs, or the use of a properly designed regional structural stormwater BMP. Routine maintenance of structural stormwater BMPs already required by this permit cannot be used to meet this requirement.