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 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 100 4. Two-year 24-hr rainfall, P2 in 3.46 5. Land Slope, s ft/ft 0.034 6. Compute Tt 0.007 (nL)0.8 hr 0.016 + + Tt = P20.5s0.4 Sheet Flow Sub-Total 0.016 hours Shallow Concentrated Flow Segment ID 2 Pavement 7. Surface Description 8. Flow Length, L ft 48 9. Watercourse Slope, s ft/ft 0.024 10. Average Velocity, V (NEH table 15-3) ft/s 3.16 11. Compute Tt L hr 0.004 + + Tt = 3600 V

+ Tt = 3600 V Shallow Conc. Flow Sub-Total 0.004 hours Channel Flow Segment ID 3 4 5 12. Flow Length, L ft 65 110 66 13. Cross Sectional flow area, a ft2 0.61 0.61 0.61 14. Wetted Perimeter, Pw ft 2.00 2.00 2.00 15. Hydraulic Radius, r r = a / Pw ft 0.31 0.31 0.31 16. Channel Slope, s ft/ft 0.026 0.005 0.070 17. Manning's Roughness Coeff., n 0.012 0.012 0.012 18. Velocity, V V = (1.49 r2/3 s1/2 ) / n ft/s 9.11 3.98 14.89 19. Compute Tt L hr 0.002 + 0.008 + 0.001 Tt = 3600 V Channel Flow Sub-Total 0.011 hours Channel Flow Segment ID 6 20. Flow Length, L ft 96 21. Cross Sectional flow area, a ft2 0.61 22. Wetted Perimeter, Pw ft 2.00 23. Hydraulic Radius, r r = a / Pw ft 0.31 24. Channel

meter, Pw ft 2.00 23. Hydraulic Radius, r r = a / Pw ft 0.31 24. Channel Slope, s ft/ft 0.080 25. Manning's Roughness Coeff., n 0.012 26. Velocity, V V = (1.49 r2/3 s1/2 ) / n ft/s 15.91 27. Compute Tt L hr 0.002 + + Tt = 3600 V Channel Flow Sub-Total 0.002 hours Watershed or subarea Tc or Tt Total Tc (hours) = 0.032 hours (Add Sub-Total Tt from prior steps) Software Limitations Require Minimum Tc = 2 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 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-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

Hydrograph Report File: Eagle Rock Proposed (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1A-U Open Space C Hyd. No. 5 Hydrograph Type = NRCS Runoff Peak Flow = 0.389 cfs Storm Frequency = 2-yr Time to Peak = 12.17 hrs Time Interval = 1 min Runoff Volume = 1,478 cuft Drainage Area = 0.33 ac Curve Number = 74.00 Tc Method = User Time of Conc. (Tc) = 11.0 min Total Rainfall = 3.46 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 0.389 cfs 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 Q (cfs) 0.2 0.18 0.16 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)

Hydrograph Report File: Eagle Rock Proposed (Current).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1A-U Woods C Hyd. No. 6 Hydrograph Type = NRCS Runoff Peak Flow = 0.074 cfs Storm Frequency = 2-yr Time to Peak = 12.18 hrs Time Interval = 1 min Runoff Volume = 291 cuft Drainage Area = 0.08 ac Curve Number = 70.00 Tc Method = User Time of Conc. (Tc) = 11.0 min Total Rainfall = 3.46 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 0.074 cfs 0.072 0.068 0.064 0.06 0.056 0.052 0.048 0.044 0.04 Q (cfs) 0.036 0.032 0.028 0.024 0.02 0.016 0.012 0.008 0.004 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-1A-U Imp Hyd. No. 7 Hydrograph Type = NRCS Runoff Peak Flow = 1.690 cfs Storm Frequency = 2-yr Time to Peak = 12.10 hrs Time Interval = 1 min Runoff Volume = 5,490 cuft Drainage Area = 0.5 ac Curve Number = 98.00 Tc Method = User Time of Conc. (Tc) = 2.0 min Total Rainfall = 3.46 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 1.690 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-1A-U Hyd. No. 8 Hydrograph Type = Junction Peak Flow = 2.062 cfs Storm Frequency = 2-yr Time to Peak = 12.10 hrs Time Interval = 1 min Hydrograph Volume = 7,259 cuft Inflow Hydrographs = 5, 6, 7 Total Contrib. Area = 0.91 ac Qp = 2.062 cfs 3 2 Q (cfs) 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-1A-U Open Space C PR-1A-U Woods C PR-1A-U Imp PR-1A-U