Laserfiche WebLink
<br />Page 9 of 26 <br />Permit No: MNRIOOOOI <br /> <br />an individual permit application. IfMPCA's written notification requires a response, <br />failure to respond within the specified timeframe constitntes a pennit violation. <br /> <br />5. The SWPPP must factor in any findings of and include any storm water mitigation measures <br />required as the result of any environmental, archeological or other required local, state or federal <br />review conducted for the project. For the purposes of this pennit provision, mitigation measures <br />mean avoiding, minimizing, rectifying (e.g., repairing, rehabilitating, restoring), reducing, <br />eliminating or compensating for impacts related to: (1) storm water discharges associated with <br />the project's construction activity; and (2) erosion prevention, sediment control and the <br />pennanent storm water management system for the project. <br /> <br />6. The SWPPP mnst provide additional measures as necessary to assure compliance with snrface <br />and ground water standards in Minn. R. chapters 7050 and 7060 in karst areas and to ensure <br />protection of drinking water supply management areas (see Minn. R. 4725A450). <br /> <br />7. If runoff from the site discharges to an impaired water which has an approved TMDL <br />implementation plan containing requirements for construction storm water discharges, the <br />Permittee must inclnde the following in the SWPPP: <br /> <br />a. identify the receiving water and the areas of the site discharging to it; and <br /> <br />b. BMPs that are appropriate for the site and sufficient to comply with all <br />applicable requirements of the TMDL implementation plan. <br /> <br />B. TEMPORARY SEDIMENT BASINS <br /> <br />Where ten (10) or more acres of disturbed soil drain to a common location, a temporary (or <br />pemlanent) sediment basin must be provided prior to the runoff leaving the construction site or <br />entering surface waters. The Permittee is encouraged, but not required, to install temporary <br />sediment basins where appropriate in areas with steep slopes or highly erodible soils even if less than <br />ten (10) acres drains to one area. The basins must be designed and constructed according to the <br />following requirements: <br /> <br />1. The basins must provide storage below the outlet pipe for a calculated volume of runoff from a 2 <br />year, 24 hour storm from each acre drained to the basin, except that in no case shall the basin <br />provide less than 1800 cubic feet of storage below the outlet pipe from each acre drained to the <br />basin. <br /> <br />2. Where no such calculation has been performed, a temporary (or pemlanent) sediment basin <br />providing 3,600 cubic feet of storage below the outlet pipe per acre drained to the basin, shall be <br />provided where attainable until final stabilizatiou of the site. <br /> <br />3. Temporary basin outlets must be designed to prevent short-circuiting and the discharge of <br />floating debris. The basin must be designed with the ability to allow complete basin drawdown <br />(e.g., perforated riser pipe wrapped with filter fabric and covered with crushed gravel, pumps or <br />otller means, see Part IV.D.) for maintenance activities, and provide a stabilized emergency <br />overflow to prevent failure of pond integrity. Energy dissipation must be provided for the basin <br />outlet (see Part IV.BA). <br /> <br />wq~stm12~51 <br />