12 2026 02 12 Crestmont CC Stormwater Management Report

EX-2-UNDISTURBED WATERSHED

Project: Eagle Rock Avenue By: TEG Date: 10/20/2025 Location: West Orange, NJ Checked By: MJV Date Checked: 10/20/2025 Circle One: Present Developed Future Existing Watershed EX-2-U Impervious Circle One: Tc Tt through subarea Include a map, schematic, or description of flow segments. Sheet Flow (Applicable to Tc Only) Segment ID 1 1. Surface Description (NEH table 15-1) Smooth Surfaces 2. Manning's Roughness Coeff., n (NEH table 15-1) 0.011 3. Flow Length, L (total L < 100 ft) ft 100 4. Two-year 24-hr rainfall, P2 in 4.08 5. Land Slope, s ft/ft 0.043 0.8 6. Compute Tt 0.007 (nL) hr 0.013 + + Tt = 0.5 0.4 P2 s Sheet Flow Sub-Total 0.013 hours Shallow Concentrated Flow Segment ID 2 3 4 7. Surface Description Pavement Woodlands Pavement 8. Flow Length, L ft 340 109 187 9. Watercourse Slope, s ft/ft 0.074 0.058 0.048 10. Average Velocity, V (NEH table 15-3) ft/s 5.54 1.21

0.074 0.058 0.048 10. Average Velocity, V (NEH table 15-3) ft/s 5.54 1.21 4.47 11. Compute Tt L hr 0.017 + 0.025 + 0.012 Tt = 3600 V Shallow Conc. Flow Sub-Total 0.054 hours Channel Flow Segment ID 5 6 12. Flow Length, L ft 56 125 2 13. Cross Sectional flow area, a ft 0.61 0.61 14. Wetted Perimeter, Pw ft 1.96 1.96 15. Hydraulic Radius, r r = a / Pw ft 0.31 0.31 16. Channel Slope, s ft/ft 0.027 0.009 17. Manning's Roughness Coeff., n 0.013 0.013 2/3 1/2 18. Velocity, V V = (1.49 r s ) / n ft/s 8.67 5.13 19. Compute Tt L hr 0.002 + 0.007 + Tt = 3600 V Channel Flow Sub-Total 0.009 hours Watershed or subarea Tc or Tt Total Tc (hours) = 0.076 hours (Add Sub-Total Tt from prior steps)

Total Tc (hours) = 0.076 hours (Add Sub-Total Tt from prior steps) Total Tc (minutes) = 5 minutes \\langan.com\data\PAR\data8\101049801\Project Data\_Discipline\Site Civil\Stormwater\Time of Concentration Calcs\Future Existing TC EX-2-U Impervious v1.2

Project: Eagle Rock Avenue By: TEG Date: 10/20/2025 Location: West Orange, NJ Checked By: MJV Date Checked: 10/20/2025 Circle One: Present Developed Future Existing Watershed EX-2-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 Woods Dense 1. Surface Description (NEH table 15-1) Underbrush 2. Manning's Roughness Coeff., n (NEH table 15-1) 0.40 3. Flow Length, L (total L < 100 ft) ft 100 4. Two-year 24-hr rainfall, P2 in 4.08 5. Land Slope, s ft/ft 0.058 0.8 6. Compute Tt 0.007 (nL) hr 0.206 + + Tt = 0.5 0.4 P2 s Sheet Flow Sub-Total 0.206 hours Shallow Concentrated Flow Segment ID 2 3 7. Surface Description Woodlands Pavement 8. Flow Length, L ft 228 117 9. Watercourse Slope, s ft/ft 0.051 0.055 10. Average Velocity, V (NEH table 15-3) ft/s 1.13 4.76 11. Compute Tt

ft/ft 0.051 0.055 10. Average Velocity, V (NEH table 15-3) ft/s 1.13 4.76 11. Compute Tt L hr 0.056 + 0.007 + Tt = 3600 V Shallow Conc. Flow Sub-Total 0.063 hours Channel Flow Segment ID 4 5 12. Flow Length, L ft 56 125 2 13. Cross Sectional flow area, a ft 0.61 0.61 14. Wetted Perimeter, Pw ft 1.96 1.96 15. Hydraulic Radius, r r = a / Pw ft 0.31 0.31 16. Channel Slope, s ft/ft 0.027 0.009 17. Manning's Roughness Coeff., n 0.013 0.013 2/3 1/2 18. Velocity, V V = (1.49 r s ) / n ft/s 8.67 5.13 19. Compute Tt L hr 0.002 + 0.007 + Tt = 3600 V Channel Flow Sub-Total 0.009 hours Watershed or subarea Tc or Tt Total Tc (hours) = 0.278 hours (Add Sub-Total Tt from prior steps)

Total Tc (hours) = 0.278 hours (Add Sub-Total Tt from prior steps) Total Tc (minutes) = 17 minutes \\langan.com\data\PAR\data8\101049801\Project Data\_Discipline\Site Civil\Stormwater\Time of Concentration Calcs\Future Existing TC EX-2-U Pervious v1.2

Hydrograph Report File: Eagle Rock Existing (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 EX-2-U Open Space C Hyd. No. 38 Hydrograph Type = NRCS Runoff Peak Flow = 1.147 cfs Storm Frequency = 2-yr Time to Peak = 12.23 hrs Time Interval = 1 min Runoff Volume = 5,109 cuft Drainage Area = 0.86 ac Curve Number = 74.00 Tc Method = User Time of Conc. (Tc) = 17.0 min Total Rainfall = 4.08 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 1.147 cfs 2 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 Q (cfs) 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Time (hrs)

Hydrograph Report File: Eagle Rock Existing (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 EX-2-U Woods C Hyd. No. 39 Hydrograph Type = NRCS Runoff Peak Flow = 1.035 cfs Storm Frequency = 2-yr Time to Peak = 12.25 hrs Time Interval = 1 min Runoff Volume = 4,716 cuft Drainage Area = 0.95 ac Curve Number = 70.00 Tc Method = User Time of Conc. (Tc) = 17.0 min Total Rainfall = 4.08 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 1.035 cfs 2 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 Q (cfs) 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Time (hrs)

Hydrograph Report File: Eagle Rock Existing (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 EX-2-U Gravel C Hyd. No. 40 Hydrograph Type = NRCS Runoff Peak Flow = 0.271 cfs Storm Frequency = 2-yr Time to Peak = 12.12 hrs Time Interval = 1 min Runoff Volume = 868 cuft Drainage Area = 0.08 ac Curve Number = 89.00 Tc Method = User Time of Conc. (Tc) = 5.0 min Total Rainfall = 4.08 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 0.271 cfs 0.28 0.26 0.24 0.22 0.2 0.18 0.16 Q (cfs) 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Time (hrs)