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

V Channel Flow Sub-Total 0.015 hours Watershed or subarea Tc or Tt Total Tc (hours) = 0.068 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\Current Existing TC EX-2-D 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 Current Existing Watershed EX-2-D 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 3.46 5. Land Slope, s ft/ft 0.066 0.8 6. Compute Tt 0.007 (nL) hr 0.213 + + Tt = 0.5 0.4 P2 s Sheet Flow Sub-Total 0.213 hours Shallow Concentrated Flow Segment ID 2 7. Surface Description Woodlands 8. Flow Length, L ft 100 9. Watercourse Slope, s ft/ft 0.081 10. Average Velocity, V (NEH table 15-3) ft/s 1.43 11. Compute Tt L hr 0.019 + +

ft/s 1.43 11. Compute Tt L hr 0.019 + + Tt = 3600 V Shallow Conc. Flow Sub-Total 0.019 hours Channel Flow Segment ID 3 4 12. Flow Length, L ft 191 125 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 0.013 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 6.14 5.13 19. Compute Tt L hr 0.009 + 0.007 + Tt = 3600 V Channel Flow Sub-Total 0.015 hours Watershed or subarea Tc or Tt Total Tc (hours) = 0.248 hours (Add Sub-Total Tt from prior steps) Total Tc (minutes) = 15 minutes \\langan.com\data\PAR\data8\101049801\Project Data\_Discipline\Site

steps) Total Tc (minutes) = 15 minutes \\langan.com\data\PAR\data8\101049801\Project Data\_Discipline\Site Civil\Stormwater\Time of Concentration Calcs\Current Existing TC EX-2-D Pervious v1.2

Hydrograph Report File: Eagle Rock Existing (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 EX-2-D Open Space D Hyd. No. 25 Hydrograph Type = NRCS Runoff Peak Flow = 0.588 cfs Storm Frequency = 2-yr Time to Peak = 12.20 hrs Time Interval = 1 min Runoff Volume = 2,388 cuft Drainage Area = 0.41 ac Curve Number = 80.00 Tc Method = User Time of Conc. (Tc) = 15.0 min Total Rainfall = 3.46 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 0.588 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)

Hydrograph Report File: Eagle Rock Existing (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 EX-2-D Woods D Hyd. No. 26 Hydrograph Type = NRCS Runoff Peak Flow = 1.264 cfs Storm Frequency = 2-yr Time to Peak = 12.20 hrs Time Interval = 1 min Runoff Volume = 5,187 cuft Drainage Area = 1.02 ac Curve Number = 77.00 Tc Method = User Time of Conc. (Tc) = 15.0 min Total Rainfall = 3.46 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 1.264 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 (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 EX-2-D Gravel D Hyd. No. 27 Hydrograph Type = NRCS Runoff Peak Flow = 0.214 cfs Storm Frequency = 2-yr Time to Peak = 12.10 hrs Time Interval = 1 min Runoff Volume = 636 cuft Drainage Area = 0.07 ac Curve Number = 91.00 Tc Method = User Time of Conc. (Tc) = 4.0 min Total Rainfall = 3.46 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 0.214 cfs 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 Q (cfs) 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 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 (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 EX-2-D Impervious Hyd. No. 28 Hydrograph Type = NRCS Runoff Peak Flow = 3.213 cfs Storm Frequency = 2-yr Time to Peak = 12.10 hrs Time Interval = 1 min Runoff Volume = 10,658 cuft Drainage Area = 0.91 ac Curve Number = 98.00 Tc Method = User Time of Conc. (Tc) = 4.0 min Total Rainfall = 3.46 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 3.213 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)

Hydrograph Report File: Eagle Rock Existing (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 EX-2-D Hyd. No. 30 Hydrograph Type = Junction Peak Flow = 4.802 cfs Storm Frequency = 2-yr Time to Peak = 12.12 hrs Time Interval = 1 min Hydrograph Volume = 18,870 cuft Inflow Hydrographs = 25, 26, 27, 28 Total Contrib. Area = 2.41 ac Qp = 4.802 cfs 5 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) EX-2-D Open Space D EX-2-D Woods D EX-2-D Gravel D EX-2-D Impervious EX-2-D

Hydrograph Report File: Eagle Rock Existing (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 EX-2-D Open Space D Hyd. No. 25 Hydrograph Type = NRCS Runoff Peak Flow = 1.180 cfs Storm Frequency = 10-yr Time to Peak = 12.20 hrs Time Interval = 1 min Runoff Volume = 4,803 cuft Drainage Area = 0.41 ac Curve Number = 80.00 Tc Method = User Time of Conc. (Tc) = 15.0 min Total Rainfall = 5.38 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 1.180 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)