The following performance criteria shall be addressed for stormwater management at all sites:
A. All site designs shall establish stormwater BMP's to control the peak flow rate 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.
B. Stormwater runoff generated from new developments shall not discharge untreated stormwater directly into a jurisdictional wetland or local water body without adequate treatment. Where such discharges are proposed, the impact on wetland functional values shall be assessed using a method in the Stormwater Design Manual.
C. For new developments, structural stormwater BMP's shall be designed to remove 80% of the average annual post development total suspended solids load (TSS) at the initial flows. It is presumed that a BMP complies with this performance standard if it is: Sized to capture the prescribed water quality volume (WQv), Designed according to the specific performance criteria outlined in the stormwater design manual, constructed properly, and maintained adequately and regularly.
D. To protect stream channels from degradation, specific channel protection criteria shall be provided as prescribed in the current stormwater design manual.
E. Stormwater discharges to critical areas with sensitive resources(Division of Nature Preserve check part B) (i.e., cold water fisheries, shellfish beds, swimming beaches, recharge areas, water supply reservoirs) may be subject to additional performance criteria based on minimum state of Indiana water quality standards for the specific receiving water.
F. The calculations for determining peak flows as found in the stormwater design manual shall be used for sizing all stormwater management practices.
(Ord. 08-29, 2008)