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b) Where vehicle fueling and maintenance occur. c) 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. d) Where high levels of contaminants in soil or groundwater will be mobilized by the infiltrating stormwater. 2) Restrict the use of infiltration techniques to achieve the conditions for post -construction ❑ Yes ® No stormwater management in the Permit (Part III.D.5.a(2)), without higher engineering review, sufficient to provide a functioning treatment system and prevent adverse impacts to groundwater, when the infiltration device will be constructed in areas: a) With predominately Hydrologic Soil Group D (clay) soils. b) Within 1,000 feet up -gradient, or 100 feet down -gradient of active karst features. c) Within a Drinking Water Supply Management Area (DWSMA) as defined in Minn. R. 4720.5100, subp. 13. d) Where soil infiltration rates are more than 8.3 inches per hour. 3) For linear projects where the lack of right-of-way precludes the installation of volume ❑ Yes ® No control practices that meet the conditions for post -construction stormwater management in the Permit (Part II I.D.5.a(2)), the permittee's regulatory mechanism(s) may allow exceptions as described in the Permit (Part III.D.5.a(3)(b)). The permittee's regulatory mechanism(s) shall ensure that a reasonable attempt be made to obtain right-of-way during the project planning process. 4. Mitigation provisions: The permittee's regulatory mechanism(s) shall ensure that any stormwater discharges of TSS and/or TP not addressed on the site of the original construction activity are addressed through mitigation and, at a minimum, shall ensure the following requirements are met: a. Mitigation project areas are selected in the following order of preference: ❑ Yes ® No 1) Locations that yield benefits to the same receiving water that receives runoff from the original construction activity. 2) Locations within the same Minnesota Department of Natural Resource (DNR) catchment area as the original construction activity. 3) Locations in the next adjacent DNR catchment area up -stream 4) Locations anywhere within the permittee's jurisdiction. b. Mitigation projects must involve the creation of new structural stormwater BMPs or the ❑ Yes ® No retrofit of existing structural stormwater BMPs, or the use of a properly designed regional structural stormwater BMP. c. Routine maintenance of structural stormwater BMPs already required by this permit cannot ❑ Yes ® No be used to meet mitigation requirements of this part. d. Mitigation projects shall be completed within 24 months after the start of the original ❑ Yes ® No construction activity. e. The permittee shall determine, and document, who will be responsible for long-term ❑ Yes ® No maintenance on all mitigation projects of this part. f. If the permittee receives payment from the owner and/or operator of a construction activity ❑ Yes ® No for mitigation purposes in lieu of the owner or operator of that construction activity meeting the conditions for post -construction stormwater management in Part III.D.5.a(2), the permittee shall apply any such payment received to a public stormwater project, and all projects must be in compliance with Part III.D.5.a(4)(a)-(e). 5. Long-term maintenance of structural stormwater BMPs: The permittee's regulatory mechanism(s) shall provide for the establishment of legal mechanisms between the permittee and owners or operators responsible for the long-term maintenance of structural stormwater BMPs not owned or operated by the permittee, that have been implemented to meet the conditions for post -construction stormwater management in the Permit (Part III.D.5.a(2)). This only includes structural stormwater BMPs constructed after the effective date of this permit and that are directly connected to the permittee's MS4, and that are in the permittee's jurisdiction. The legal mechanism shall include provisions that, at a minimum: a. Allow the permittee to conduct inspections of structural stormwater BMPs not owned or ® Yes ❑ No operated by the permittee, perform necessary maintenance, and assess costs for those structural stormwater BMPs when the permittee determines that the owner and/or operator of that structural stormwater BMP has not conducted maintenance. b. Include conditions that are designed to preserve the permittee's right to ensure maintenance ® Yes ❑ No responsibility, for structural stormwater BMPs not owned or operated by the permittee, when those responsibilities are legally transferred to another party. c. Include conditions that are designed to protect/preserve structural stormwater BMPs and ® Yes ❑ No �.pca.state.mn.us 651-296-6300 • 800-657-3864 TTY 651-282-5332 or 800-657-3864 • Available in alternative formats wq-strm4-49a • 5131113 Page 6 of 15