(A) Unless judged by the MS4 Coordinator to be exempt or granted a waiver, the following performance criteria shall be addressed for stormwater management at all sites one acre or greater:
(1) All site designs shall establish stormwater management practices to control the peak flow rates of stormwater discharge associated with specified design storms and reduce the generation of stormwater. These practices should seek to utilize pervious areas for stormwater treatment and to infiltrate stormwater runoff from driveways, sidewalks, rooftops, parking lots, and landscaped areas to the maximum extent practical to provide treatment for both water quality and quantity.
(2) All stormwater runoff generated from new development shall not discharge directly into a jurisdictional wetland or local water body without adequate treatment. Where such discharges are proposed, the impact of the proposal on wetland functional values shall be assessed using a method acceptable to the MS4 Coordinator. In no case shall the impact on functional values be any less than allowed by the U.S. Army Corps of Engineers (U.S. ACE) or other agencies regulating wetlands in the State of Indiana.
(3) To protect stream channels from degradation, specific channel protection criteria shall be provided as prescribed in § 52.05, Reference Manuals.
(4) Stormwater discharges to critical areas with sensitive resources (such as cold-water fisheries, shellfish beds, swimming beaches, recharge areas, water supply reservoirs) may be subject to additional performance criteria, or may need to utilize or restrict certain stormwater management practices.
(5) Certain industrial sites are required to prepare and implement a stormwater pollution prevention plan, and shall file a Notice of Intent (N0I) under the provisions of the National Pollutant Discharge Elimination System (NPDES). The stormwater pollution prevention plan requirement applies to both existing and new industrial sites.
(6) Stormwater discharges from land uses or activities with higher potential pollutant loadings, known as HOTSPOTS, may require the use of specific structural STPs and pollution prevention practices.
(7) Prior to design, applicants are required to consult with the MS4 Coordinator to determine if they are subject to additional stormwater design requirements.
(8) The calculations for determining peak flows as found in § 52.05 Reference Manuals, or other municipal ordinances, shall be used for sizing all stormwater management practices.
(Ord. 2007-05, passed 4-17-07)