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-1A-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 Dense Grasses 1. Surface Description (NEH table 15-1) Underbrush 2. Manning's Roughness Coeff., n (NEH table 15-1) 0.24 0.40 3. Flow Length, L (total L < 100 ft) ft 73 27 4. Two-year 24-hr rainfall, P2 in 3.46 3.46 5. Land Slope, s ft/ft 0.080 0.068 6. Compute Tt 0.007 (nL)0.8 hr 0.102 + 0.074 + Tt = P20.5s0.4 Sheet Flow Sub-Total 0.176 hours Shallow Concentrated Flow Segment ID 3 4 Grassed Woodlands 7. Surface Description

Woodlands 7. Surface Description Waterways 8. Flow Length, L ft 21 198 9. Watercourse Slope, s ft/ft 0.090 0.110 10. Average Velocity, V (NEH table 15-3) ft/s 1.51 5.34 11. Compute Tt L hr 0.004 + 0.010 + Tt = 3600 V Shallow Conc. Flow Sub-Total 0.014 hours Channel Flow Segment ID 12. Flow Length, L ft 13. Cross Sectional flow area, a ft2 14. Wetted Perimeter, Pw ft 15. Hydraulic Radius, r r = a / Pw ft 16. Channel Slope, s ft/ft 17. Manning's Roughness Coeff., n 18. Velocity, V V = (1.49 r2/3 s1/2 ) / n ft/s 19. Compute Tt L hr + + Tt = 3600 V Channel Flow Sub-Total 0.000 hours Watershed or subarea Tc or Tt Total Tc (hours) = 0.190 hours (Add Sub-Total Tt from prior steps) Total Tc (minutes) = 11 minutes \\langan.com\data\PAR\data8\101049801\Project

Sub-Total Tt from prior steps) Total Tc (minutes) = 11 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-1A-U Pervious v1.2