Revised Stormwater Management Report

DocuSign Envelope ID: DB0533B0-B14B-449D-A0A8-3B9C3C0DF5D9 Porous Pavement system #6 Porous pavement #6 collects stormwater from the parking lot between Buildings B and C, Building C roof and grass areas around the building. The majority of the drainage area is the building roof or the porous pavement surface. The ratio of other contributing areas to the Porous pavement area is 1.9 : 1 The system will have soil replacement with a permeability of 4 inches per hour with a factor of safety of 2. The proposed Tc for the area flowing to PP6 uses the following input Sheet flow 40 lf @2% over pavement Tc= .6 minutes Pipe flow 450 lf pipe , 2.5 fps Tc = 3 minutes Total Tc = 3.6 minutes The porous pavement system is considered green technology for both groundwater recharge and water quality. PA-1 Discharge Summary STORM WQ 2 YR 10 YR 100 YR EXISTING 6.84 15.78 35.37 PERMITTED #1 #5 #6 3.43 11.5 28.3 0 .19 .60 1.18 0 0 1.06 4.67 0 .22 2.63 11.67 5 OVERLAND FLOW .42 2.46 5.01 10.26 POA 1 .42 2.46 5.08 10.89