Penn Hills, PA Environmental Rules: Stormwater Management (2026)

Post-development discharge rates shall not exceed the predevelopment discharge rates for the one-, two-, five-, ten-, twenty-five-, fifty-, and 100-year, twenty-four-hour storm events. This is the equivalent to a 100% release rate area when compared to those rates shown in the maps contained in Appendix A (New and Existing Release Rate Management Districts).[1] This predevelopment to post-development control is not to be misconstrued as the same as the "Conditional Direct Discharge" areas on the Release Rate maps. If it is shown that the peak rates of discharge indicated by the post-development analysis are less than or equal to the peak rates of discharge indicated by the predevelopment analysis for one-, two-, five-, ten-, twenty-five-hour and 100-year, twenty-four-hour storms, then the requirements of this section have been met. Otherwise, the applicant shall provide additional controls as necessary to satisfy the peak rate of discharge requirement. Peak flows should be computed using the methods included in the chapter titled "Stormwater Calculations and Methodology" of the PADEP Stormwater Management BMP Manual. [1] Editor's Note: Said appendix is included as an attachment to this chapter.

(b) For areas covered by a release rate map from an approved Act 167 Stormwater Management Plan:

(1)