12 2026 02 12 Crestmont CC Stormwater Management Report

Hydrograph Report File: Eagle Rock Proposed (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1C-D Impervious Hyd. No. 25 Hydrograph Type = NRCS Runoff Peak Flow = 1.001 cfs Storm Frequency = 100-yr Time to Peak = 12.10 hrs Time Interval = 1 min Runoff Volume = 3,369 cuft Drainage Area = 0.11 ac Curve Number = 98.00 Tc Method = User Time of Conc. (Tc) = 2.0 min Total Rainfall = 9.24 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 1.001 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 Proposed (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1C-D Hyd. No. 26 Hydrograph Type = Junction Peak Flow = 3.556 cfs Storm Frequency = 100-yr Time to Peak = 12.10 hrs Time Interval = 1 min Hydrograph Volume = 10,770 cuft Inflow Hydrographs = 24, 25 Total Contrib. Area = 0.43 ac Qp = 3.556 cfs 4 3 Q (cfs) 2 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) PR-1C-D Open Space D PR-1C-D Impervious PR-1C-D

PR-1C-UNDISTURBED WATERSHED

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-1C-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 Smooth Surfaces 1. Surface Description (NEH table 15-1) 2. Manning's Roughness Coeff., n (NEH table 15-1) 0.011 3. Flow Length, L (total L < 100 ft) ft 60 4. Two-year 24-hr rainfall, P2 in 3.46 5. Land Slope, s ft/ft 0.032 6. Compute Tt 0.007 (nL)0.8 hr 0.011 + + Tt = P20.5s0.4 Sheet Flow Sub-Total 0.011 hours Shallow Concentrated Flow Segment ID 2 3 4 Pavement Pavement Pavement 7. Surface Description 8. Flow Length, L ft 66 474 164 9. Watercourse Slope, s ft/ft 0.033 0.073 0.016 10. Average Velocity, V (NEH table 15-3) ft/s 3.71 5.50 2.60 11. Compute Tt L

city, V (NEH table 15-3) ft/s 3.71 5.50 2.60 11. Compute Tt L hr 0.005 + 0.024 + 0.017 Tt = 3600 V Shallow Conc. Flow Sub-Total 0.046 hours Channel Flow Segment ID 5 6 12. Flow Length, L ft 36 67 13. Cross Sectional flow area, a ft2 0.88 0.88 14. Wetted Perimeter, Pw ft 2.40 2.40 15. Hydraulic Radius, r r = a / Pw ft 0.37 0.37 16. Channel Slope, s ft/ft 0.032 0.042 17. Manning's Roughness Coeff., n 0.013 0.013 18. Velocity, V V = (1.49 r2/3 s1/2 ) / n ft/s 10.43 11.98 19. Compute Tt L hr 0.001 + 0.002 + Tt = 3600 V Channel Flow Sub-Total 0.003 hours Watershed or subarea Tc or Tt Total Tc (hours) = 0.060 hours (Add Sub-Total Tt from prior steps) Total Tc (minutes) = 4 minutes \\langan.com\data\PAR\data8\101049801\Project Data\_Discipline\Site Civil\Stormwater\Time of Concentration Calcs\Proposed Tc Calcs\Current Proposed

Total Tc (minutes) = 4 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-1C-U Impervious v1.2

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-1C-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 Dense Grasses 1. Surface Description (NEH table 15-1) 2. Manning's Roughness Coeff., n (NEH table 15-1) 0.24 3. Flow Length, L (total L < 100 ft) ft 100 4. Two-year 24-hr rainfall, P2 in 3.46 5. Land Slope, s ft/ft 0.090 6. Compute Tt 0.007 (nL)0.8 hr 0.126 + + Tt = P20.5s0.4 Sheet Flow Sub-Total 0.126 hours Shallow Concentrated Flow Segment ID 2 3 4 Grassed Pavement Pavement 7. Surface Description Waterways 8. Flow Length, L ft 178 207 164 9. Watercourse Slope, s ft/ft 0.078 0.067

ft 178 207 164 9. Watercourse Slope, s ft/ft 0.078 0.067 0.016 10. Average Velocity, V (NEH table 15-3) ft/s 4.50 5.27 2.60 11. Compute Tt L hr 0.011 + 0.011 + 0.017 Tt = 3600 V Shallow Conc. Flow Sub-Total 0.039 hours Channel Flow Segment ID 5 6 12. Flow Length, L ft 36 67 13. Cross Sectional flow area, a ft2 0.88 0.88 14. Wetted Perimeter, Pw ft 2.40 2.40 15. Hydraulic Radius, r r = a / Pw ft 0.37 0.37 16. Channel Slope, s ft/ft 0.032 0.042 17. Manning's Roughness Coeff., n 0.013 0.013 18. Velocity, V V = (1.49 r2/3 s1/2 ) / n ft/s 10.43 11.98 19. Compute Tt L hr 0.001 + 0.002 + Tt = 3600 V Channel Flow Sub-Total 0.003 hours Watershed or subarea Tc or Tt Total Tc (hours) = 0.167 hours (Add Sub-Total Tt from prior steps)

Total Tc (hours) = 0.167 hours (Add Sub-Total Tt from prior steps) Total Tc (minutes) = 10 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-1C-U Pervious v1.2

Hydrograph Report File: Eagle Rock Proposed (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1C-U Open Space C Hyd. No. 28 Hydrograph Type = NRCS Runoff Peak Flow = 0.902 cfs Storm Frequency = 2-yr Time to Peak = 12.15 hrs Time Interval = 1 min Runoff Volume = 3,213 cuft Drainage Area = 0.73 ac Curve Number = 74.00 Tc Method = User Time of Conc. (Tc) = 10.0 min Total Rainfall = 3.46 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 0.902 cfs 1 0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 Q (cfs) 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 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)