Ordinance - #14-09 - 09/23/2014 - Laserfiche WebLink

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At a minimum these facilities must conform to the most current technology as reflected in the current version of the Minnesota Pollution Control Agency's publication, "Protecting Water Quality in Urban Areas" and the current requirements found in the same agency's NPDES permits for stormwater associated with construction activities. Section 117 -394 (a) is hereby amended as follows (additions indicated as underline, deletions indicated as strilEe- through): (a) Runoff must not be discharged directly into wetlands without appropriate quality (i.e., treated) and quantity runoff control, depending on the individual wetland's vegetation sensitivity. See the current version of the Minnesota Pollution Control Agency's publication, "Storm -Water and Wetlands: Planning and Evaluation Guidelines for Addressing Potential Impacts of Urban Storm -Water and Snow -Melt Runoff on Wetlands" for guidance. The minimum level of treatment required for discharge to wetlands is to meet the NURP Guidelines as follows: (1) A permanent pool ( "dead storage') volume below the principal spillway (normal outlet) which shall be greater than or equal to the runoff from a 2.5 inch storm over the entire contributing area assuming full development. It shall have an annual removal efficiency of 60% total phosphorus and 90% total suspended solids. (2) A permanent pool average depth (basin volume/ basin area) which shall be >3 feet, with a maximum depth of 10 feet. (3) Pond outlets shall have skimmers, submerged outlets or other devices that extend a minimum of 6 inches below the water surface and minimize velocities of water passing under the skimmer to less than 0.5 feet per second for rainfall events having a 99% frequency (1 year storm event). Section 117 -395 is hereby amended as follows (additions indicated as underline, deletions indicated as strip): Sec. 117 -395. — Review Impaired waters and total maximum daily loads If a site drains to a surface water that has been listed as impaired pursuant to section 303(d) of the federal Clean Water Act more stringent water quality measures will be required. If a Total Maximum Daily Load (TMDL) has been written for the impaired water then all best management practices deemed necessary to comply with the requirements of the TMDL must be implemented. Section 117 -396 is hereby amended as follows (additions indicated as underline, deletions indicated as strikEe-threugh): Sec. 117 -396. — Permit es ed. Maintenance of stormwater BMPs. (a) The design and planning of all stormwater management facilities shall include detailed maintenance and repair procedures to ensure their continued function. These plans will identify the parts or components of a stormwater management facility that need to be maintained and the equipment and skills or training necessary. Provisions for the periodic review and evaluation of the effectiveness of