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This redevelopment project is proposing a combination of WQv treatment by standard practice(s) and alternative practice(s) as shown in the following tables: Table 4: Required WQv Treatment by Alternative Practice WQv Treatment by Impervious Cover WQv Treatment by Runoff Reduction Alternative Practice Reduction (IC) Standard Practice % Area (ac) % Area (ac) % Area (ac) % Area (ac) 38 2.13 0 0 34 1.96 0 0 Table 5: WQv Required Summary P (inches) A (ac) I (ac) Rv WQv Required 1.00 5.68 2.98 0.29 8,672 cf 0.20 AF The Water Quality Volume equation has been applied to the drainage area tributary to each of the stormwater quality practices proposed for this project. The practices have been sized to accommodate the Water Quality Volume, as per the performance criteria presented in Chapter 6 and/or Chapter 9 of the Design Manual. Water quality volume calculations for each of the proposed practices are presented in Appendix C. 3.3 STEP 3 – Apply RR Techniques and Standard SMPs with RRv Capacity to Reduce Total WQv Land use change and development in the watershed increases the volume of runoff. As such, reductions in the amount of runoff from new development, accomplished through the implementation of a stormwater management plan for the site, will play an important role in the success or failure of the watershed-wide stormwater management plan. Runoff reduction techniques can be applied to manage, reduce, and treat stormwater, while maintaining and restoring natural hydrology through infiltration, evapo-transpiration, and the capture and reuse of stormwater. Volume reduction techniques by themselves typically are not sufficient to provide adequate attenuation of stormwater runoff, but they can decrease the size of the peak runoff rate reduction facilities. 3.3.1 NYSDEC Requirements for Redevelopment Section 9.2.1.B of the Design Manual indicates, “Although encouraged, meeting the RRv criteria is not required for the redevelopment activity portion of a project. The need to provide RRv shall be considered separately for each design point. For design points with a net increase in impervious area, RRv is required for the increase in impervious area only.” As such, bioretentions and a water quality unit have been applied to the project to meet the WQv objective for the redevelopment activity of the project. The increase in impervious cover will be treated as new development and both the WQv criteria and RRv criteria are met. 3.3.2 Application of Standard Stormwater Management Practices (SMPs) with RRv Capacity The following Table demonstrates a summary of the standard SMP(s) with RRv capacity that have been incorporated into the stormwater management plan for this project. The standard SMP(s) with RRv capacity have been designed in accordance with Chapter 6 of the Design Manual. Refer to the contract drawings for practice dimensions, material specifications, and installation details. Practice specific calculations are presented in Appendix C. Stormwater Pollution Prevention Plan Page 8 2241067 Page 98 of 1493