12 2026 02 12 Crestmont CC Stormwater Management Report

POROUS PAVEMENT SYSTEM DESIGN CALCULATIONS Design Notes and Standards: 1. The NJDEP water quality design storm event is 1.25 inches over a period of 2 hours. 2. The maximum ratio of additional inflow drainage area to surface area of the porous pavement system is 3:1. 3. The storage bed of the porous pavement system must drain within 72 hours. 4. The void space of the stone storage bed is assumed to be 40%. 5. The seasonal high water table or bedrock must be a minimum of 1 foot below the bottom of the storage bed. 6. The proposed porous pavement system has been designed to allow for additional storage capacity for quanitity control measures for the larger storm events. An outlet control structure has been designed which will control the rate of discharge; the underdrain system has been provided to promote complete drainage of the system. POROUS PAVEMENT BED DEPTH STORAGE WQ STORM RUNOFF MIN. UNDERDRAIN PIPE DIA. MIN. UNDERDRAIN UNDERDRAIN BED AREA (SF) SYSTEM AREA (IN) VOLUME (CF) VOLUME (CF) (IN) PIPE SLOPE (FT/FT) CAPACITY (CFS) PAPS-1 6,586 36 7,903 1,511 4 0.005 0.15 Pavement Area Cover Type Soil Type Area (ac) Area (sf) CN S Q Runoff (in) Runoff Volume (CF) Open Space/Grass C 0.01 305 74 3.51 0.07 2 PAPS-1 Open Space/Grass D 0.03 1,485 80 2.50 0.17 21 Impervious - 0.40 17,262 98 0.20 1.03 1,488 TOTAL: 0.44 19,052

0.20 1.03 1,488 TOTAL: 0.44 19,052 1,511 ADDITIONAL INFLOW DRAINAGE AREA RATIO (X:1) 1.89 ADDITIONAL INFLOW IMPERVIOUS AREA RATIO (X:1) 1.62