Unless judged by the town to be exempt or granted a waiver, the following performance criteria shall be addressed for stormwater management at all sites:
(a) 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.
(b) Annual groundwater recharge rates shall be maintained, by promoting infiltration through the use of structural and nonstructural methods.
(c) Post construction best management practices (BMPs) are installed after construction has been completed and the site has been stabilized. Installing certain BMPs, such as bioretention areas and sand filters, prior to stabilization can cause failure of the measure due to clogging from sediment. With a strict construction sequence, however, detention ponds and other BMPs can be installed initially during construction and used as permanent runoff control measures upon completion of construction activities. In those instances, the construction sequence must require that the pond is cleaned out with pertinent elevations and storage and treatment capacities reestablished as noted in the approved post construction runoff control plan.
(d) The town has adopted a policy that the control of stormwater runoff quality will be based on the management of total suspended solids. For new development, BMPs shall be designed to remove eighty percent of the average annual post developmental total suspended solids (TSS). It is presumed that a BMP complies with this performance standard if it is:
(1) Sized to capture the prescribed water quality volume (WQ_v);
(2) Designed according to the specified performance criteria outlined in the city of Indianapolis Stormwater Design and Construction Specifications Manual;
(3) Constructed properly; and
(4) Maintained regularly.
(e) In addition to TSS removal, BMPs must also be designed to treat the water quality volume (WQ_v), or the first flush of runoff. All new development projects requiring post construction runoff control plans shall be required to treat the WQ_v. Redevelopment projects will be required to obtain stormwater quality approval if the redevelopment activity disturbs more than one acre. Please refer to the city of Indianapolis Stormwater Design and Construction Specifications Manual for further details regarding calculation of the WQ_v.
(f) The BMPs in Table 5.1 are acceptable for use in the town if designed, constructed, and maintained according to the criteria set forth in the city of Indianapolis Stormwater Design and Construction Specifications Manual. It is presumed that these acceptable BMPs achieve a target TSS removal rate of eighty percent when correctly constructed and maintained.
(g) Should the developer/project site owner choose to implement a stormwater control device, method, or system not listed as one of the acceptable BMPs for the town, the developer/project site owner must provide proof that the stormwater control device, method, or system can achieve the target TSS removal rate of eighty percent when correctly constructed.

(Ord. 1044 §5, 2005).