The design of all regulated activities shall include the following to minimize stormwater impacts to reduce the surface discharge of stormwater, reduce the creation of unnecessary impervious surfaces, prevent the degradation of waters of the commonwealth and maintain as much as possible the natural hydrologic regime of the site.
(a) The applicant shall apply low impact development (LID) methods such as those listed in Appendix C, provided that use of this method does not conflict with other local codes.
(b) The applicant shall demonstrate that the design process follows the sequence noted below. The goal of the sequence is to minimize the increases in stormwater runoff and impacts to water quality resulting from the proposed regulated activity:
(1) The following items in this subsection (b) shall be addressed prior to development of other stormwater management site plan design elements:
A. Prepare an existing resource and site analysis map (ERSAM) showing environmentally sensitive areas including, but not limited to, steep slopes, ponds, lakes, streams, wetlands, hydric soils, vernal pools, stream buffers, and hydrologic soil groups. Land development, any existing recharge areas, and other requirements outlined in the municipal SALDO shall also be included;
B. Establish a stream buffer according to § 1043.17(c);
C. Prepare a draft project layout avoiding sensitive areas identified in subsection (b)(1)A. above;
D. Identify site-specific existing conditions drainage areas, discharge points, recharge areas and hydrologic soil groups A and B (areas conducive to infiltration); and
E. Evaluate nonstructural stormwater management alternatives:
1. Minimize earth disturbance;
2. Minimize impervious surfaces; and
3. Break up large impervious surfaces.
F. Determine into what management district the site falls (Appendix A), and conduct an existing conditions runoff analysis.
(2) The following items in this subsection (b) may be addressed in any order provided that all items in subsection (b)(1) above have been completed:
A. Satisfy the infiltration objective (§ 1043.16) and provide for stormwater pretreatment prior to infiltration;
B. Provide for water quality protection in accordance with § 1043.17 water quality requirements;
C. Provide stream bank erosion protection in accordance with § 1043.18 stream bank erosion requirements;
D. Prepare final project design to maintain existing conditions drainage areas and discharge points, to minimize earth disturbance and impervious surfaces, and, to the maximum extent possible, to ensure that the remaining site development has no surface or point discharge;
E. Conduct a proposed conditions runoff analysis based on the final design that meets the management district requirements (§ 1043.19); and
F. Manage any remaining runoff prior to discharge through detention, bioretention, direct discharge or other structural control.
(Ord. 928, passed 6-18-2014)