2026 02 12 Crestmont CC and Eagle Rock Ave Stormwater Management Report

Project: Eagle Rock Avenue By: TEG Date: 10/21/2025 Location: West Orange, NJ Checked By: MJV Date Checked: 10/21/2025 Circle One: Present Developed Current Proposed Watershed PR-1B-U Pervious Circle One: Tc Tt through subarea Include a map, schematic, or description of flow segments. Sheet Flow (Applicable to Tc Only) Segment ID 1 2 Woods Light Woods Light 1. Surface Description (NEH table 15-1) Underbrush Underbrush 2. Manning's Roughness Coeff., n (NEH table 15-1) 0.40 0.40 3. Flow Length, L (total L < 100 ft) ft 67 23 4. Two-year 24-hr rainfall, P2 in 3.46 3.46 5. Land Slope, s ft/ft 0.068 0.505 6. Compute Tt 0.007 (nL)0.8 hr 0.153 + 0.029 + Tt = P20.5s0.4 Sheet Flow Sub-Total 0.182 hours Shallow Concentrated Flow Segment ID 3 Grassed 7. Surface Description Waterways 8. Flow Length, L ft 13 9. Watercourse Slope, s ft/ft 0.372 10. Average Velocity, V (NEH table 15-3)

ft 13 9. Watercourse Slope, s ft/ft 0.372 10. Average Velocity, V (NEH table 15-3) ft/s 9.85 11. Compute Tt L hr 0.000 + + Tt = 3600 V Shallow Conc. Flow Sub-Total 0.000 hours Channel Flow Segment ID 4 5 6 12. Flow Length, L ft 245 25 117 13. Cross Sectional flow area, a ft2 0.69 0.61 0.61 14. Wetted Perimeter, Pw ft 3.58 2.00 2.00 15. Hydraulic Radius, r r = a / Pw ft 0.19 0.31 0.31 16. Channel Slope, s ft/ft 0.010 0.080 0.023 17. Manning's Roughness Coeff., n 0.035 0.013 0.013 18. Velocity, V V = (1.49 r2/3 s1/2 ) / n ft/s 1.42 14.69 7.89 19. Compute Tt L hr 0.048 + 0.000 + 0.004 Tt = 3600 V Channel Flow Sub-Total 0.053 hours Channel Flow Segment ID 7 8 20. Flow Length, L

Flow Sub-Total 0.053 hours Channel Flow Segment ID 7 8 20. Flow Length, L ft 15 51 21. Cross Sectional flow area, a ft2 0.61 0.61 22. Wetted Perimeter, Pw ft 2.00 2.00 23. Hydraulic Radius, r r = a / Pw ft 0.31 0.31 24. Channel Slope, s ft/ft 0.055 0.021 25. Manning's Roughness Coeff., n 0.013 0.013 26. Velocity, V V = (1.49 r2/3 s1/2 ) / n ft/s 12.14 7.59 27. Compute Tt L hr 0.000 + 0.002 + Tt = 3600 V Channel Flow Sub-Total 0.002 hours Watershed or subarea Tc or Tt Total Tc (hours) = 0.237 hours (Add Sub-Total Tt from prior steps) Total Tc (minutes) = 14 minutes \\langan.com\data\PAR\data8\101049801\Project Data\_Discipline\Site Civil\Stormwater\Time of Concentration Calcs\Proposed Tc Calcs\Current Proposed TCs\Current Proposed TC PR-1B-U Pervious v1.2