Supporting Documentation · Jun 3, 2026
2026 02 12 Crestmont CC and Eagle Rock Ave Stormwater Management Report
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= APPENDIX A Existing Stormwater Discharge Calculations
= = APPENDIX A TABLE OF CONTENTS NOAA RAINFALL PRECIPITATION DATA NOAA REGION D RAINFALL DISTRIBUTION EXISTING RUNOFF CURVE NUMBER CALCULATIONS CURRENT HYDROGRAPH CALCULATIONS EX-1-DISTURBED WATERSHED Time of Concentration Calculation 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event EX-1-DISTURBED WATERSHED ALLOWABLE PEAK DISCHARGE 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event EX-1-UNDISTURBED WATERSHED Time of Concentration Calculation 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event TOTAL EXISTING FLOW TO POA-1 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event TOTAL ALLOWABLE FLOW TO POA-1 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event EX-2-DISTURBED WATERSHED Time of Concentration Calculation 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event EX-2-DISTURBED WATERSHED ALLOWABLE PEAK DISCHARGE 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event
= = EX-2-UNDISTURBED WATERSHED Time of Concentration Calculation 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event TOTAL EXISTING FLOW TO POA-2 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event TOTAL ALLOWABLE FLOW TO POA-2 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event SUMMARY OF EXISTING PEAK DISCHARGES FUTURE HYDROGRAPH CALCULATIONS EX-1-DISTURBED WATERSHED Time of Concentration Calculation 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event EX-1-DISTURBED WATERSHED ALLOWABLE PEAK DISCHARGE 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event EX-1-UNDISTURBED WATERSHED Time of Concentration Calculation 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event TOTAL EXISTING FLOW TO POA-1 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event TOTAL ALLOWABLE FLOW TO POA-1 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event
= = EX-2-DISTURBED WATERSHED Time of Concentration Calculation 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event EX-2-DISTURBED WATERSHED ALLOWABLE PEAK DISCHARGE 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event EX-2-UNDISTURBED WATERSHED Time of Concentration Calculation 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event TOTAL EXISTING FLOW TO POA-2 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event TOTAL ALLOWABLE FLOW TO POA-2 2 Year Design Storm Event 10 Year Design Storm Event 100 Year Design Storm Event SUMMARY OF EXISTING PEAK DISCHARGES
NOAA RAINFALL PRECIPITATION DATA
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NOAA NWS Current Future Precipitation Frequency PFDS 24-Hour Precipitation Current Rainfall Future Rainfall Adjustment Factor of Storms Rainfall Depth Adjustment Factor Depth (inches) Depth (inches) for Essex County (inches) for Essex County 2-Year 3.43 1.01 3.46 1.19 4.08 10-Year 5.22 1.03 5.38 1.22 6.37 25-Year1 6.46 1.04 6.72 1.26 8.13 100-Year 8.72 1.06 9.24 1.33 11.60 Notes: 1. The adjustment factors for the current and future 25-year storms was found using a weighted average of the 10- and 100-year adjustment factors.
NOAA REGION D RAINFALL DISTRIBUTION
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- Sep 29, 2026
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