J_2024 05 09_West Orange Stormwater Management Plan

Client Project # Project Name PSE&G Date 03/29/23 West Orange Switching Station Known Data and Notes 144507 Known Data: Page 1 Made By Checked By Preliminary of 19 SJM MJB X Final References Hydrologic Soil Type (HSG): USDA NRCS Web Soil Survey URBONB: Urban Land, Boonton substratum, 0 to 8 percent slopes Hydrologic Soil Group: D (no HSG listed, assume D) USBONB: Urban Land, Boonton substratum - Boonton complex, 0 to 8 percent slopes Hydrologic Soil Group: B (used HSG D for a conservative evaluation) Water Quality Design Storm is 1.25 inches of rainfall in two hours. 24-Hour Precipitation Depths: 2 Year = 10 Year = 25 Year = 100 Year = 3.42 5.21 6.44 8.71 in in in in NOAA National Weather Service Precipitation Frequency Data Server Essex County NOAA 24-hr Type D Storm Distribution Current Precipitation Adjustment Factors 2 Year = 1.01 x 3.42 = 3.45 in 5.37 in 10 Year = 1.03 x 5.21 = 100 Year = 1.06 x 8.71 = 9.23 in Future Precipitation Change Factors 1.19 x 3.42 = 4.07 2 Year = 1.22 x 5.21 = 6.36 10 Year = 100 Year = 1.33 x 8.71 = 11.58 in in in Notes: 1. Description: Impervious, Pavement >75% Grass cover, Good Yard Stone/Gravel Pad Brush, Good Non-Contributory Curve Numbers (CN): # # # # N/A HSG Rating: D D D D D 2. HydroCAD software using Calculate separate Pervious/Impervious runoff for all Curve Number (CN) calculations 3. The station crushed stone curve number was established using the equation found in the NJDEP BMP Manual, Chapter 5, where CN = 1000/(S+10), where S is equal to the storage depth in the crushed stone (in this case, 4”), with a voids ratio of 40%. https://burnsmcd.sharepoint.com/sites/PSEGSub/Shared Documents/WestOrange26kVLifecyclePrelim_144507/Dsgn/Sub/Civil/Storm_Wtr/6. 5/10/2024 4:13 PM Storm Water Management Report/Appendix A - Design Notes/Archived/West Orange Design Notes_Blake.xlsx