(A) Erosion and sediment control measures shall be designed and installed in accordance with 327 I.A.C. 15-5-1:12 (Rule 5), the town’s Standards Manual, and the state’s Stormwater Quality Manual. Unless judged by the town’s wastewater utility to be exempt or granted a waiver, the following performance criteria shall be addressed for stormwater management at all sites.
(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 untreated stormwater directly into a jurisdictional wetland or waters of the United States 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 jurisdictional stormwater authority. In no case shall the impact on functional values be any less than allowed by the Army Corp of Engineers (ACE) or the state’s Department of Natural Resources.
(3) Annual ground water recharge rates shall be maintained, by promoting infiltration through the use of structural and nonstructural methods.
(4) For new development, structural BMPs shall be designed to remove 80% of the average annual post development total suspended solids load (TSS). It is presumed that a BMP complies with this performance standard if it is:
(a) Sized to capture the prescribed water quality volume (WQv);
(b) Designed according to the specific performance criteria outlined in the local stormwater design manual;
(c) Constructed properly; and
(d) Maintained regularly.
(B) A list of pre-approved post-construction BMPs along with procedures to be followed for approval of innovative BMPs or BMPs not in the pre-approved list are provided in the town standards and specifications.