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

0.053 hours Channel Flow Segment ID 7 8 20. Flow Length, L ft 15 51 21. Cross Sectional flow area, a ft2 0.61 0.61 22. Wetted Perimeter, Pw ft 2.00 2.00 23. Hydraulic Radius, r r = a / Pw ft 0.31 0.31 24. Channel Slope, s ft/ft 0.055 0.021 25. Manning's Roughness Coeff., n 0.013 0.013 26. Velocity, V V = (1.49 r2/3 s1/2 ) / n ft/s 12.14 7.59 27. Compute Tt L hr 0.000 + 0.002 + Tt = 3600 V Channel Flow Sub-Total 0.002 hours Watershed or subarea Tc or Tt Total Tc (hours) = 0.223 hours (Add Sub-Total Tt from prior steps) Total Tc (minutes) = 13 minutes \\langan.com\data\PAR\data8\101049801\Project Data\_Discipline\Site Civil\Stormwater\Time of Concentration Calcs\Proposed Tc Calcs\Future Proposed TC PR-1B-U Pervious v1.2

Hydrograph Report File: Eagle Rock Proposed (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1B-U Open Space C Hyd. No. 15 Hydrograph Type = NRCS Runoff Peak Flow = 0.441 cfs Storm Frequency = 2-yr Time to Peak = 12.18 hrs Time Interval = 1 min Runoff Volume = 1,715 cuft Drainage Area = 0.29 ac Curve Number = 74.00 Tc Method = User Time of Conc. (Tc) = 13.0 min Total Rainfall = 4.08 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 0.441 cfs 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 Q (cfs) 0.22 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 (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1B-U Woods C Hyd. No. 16 Hydrograph Type = NRCS Runoff Peak Flow = 0.772 cfs Storm Frequency = 2-yr Time to Peak = 12.18 hrs Time Interval = 1 min Runoff Volume = 3,065 cuft Drainage Area = 0.62 ac Curve Number = 70.00 Tc Method = User Time of Conc. (Tc) = 13.0 min Total Rainfall = 4.08 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 0.772 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 Proposed (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1B-U Impervious Hyd. No. 17 Hydrograph Type = NRCS Runoff Peak Flow = 4.234 cfs Storm Frequency = 2-yr Time to Peak = 12.12 hrs Time Interval = 1 min Runoff Volume = 16,058 cuft Drainage Area = 1.18 ac Curve Number = 98.00 Tc Method = User Time of Conc. (Tc) = 7.0 min Total Rainfall = 4.08 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 4.234 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)

Hydrograph Report File: Eagle Rock Proposed (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1B-U Hyd. No. 18 Hydrograph Type = Junction Peak Flow = 5.324 cfs Storm Frequency = 2-yr Time to Peak = 12.13 hrs Time Interval = 1 min Hydrograph Volume = 20,838 cuft Inflow Hydrographs = 15, 16, 17 Total Contrib. Area = 2.09 ac Qp = 5.324 cfs 6 5 4 Q (cfs) 3 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-1B-U Open Space C PR-1B-U Woods C PR-1B-U Impervious PR-1B-U

Hydrograph Report File: Eagle Rock Proposed (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1B-U Open Space C Hyd. No. 15 Hydrograph Type = NRCS Runoff Peak Flow = 0.942 cfs Storm Frequency = 10-yr Time to Peak = 12.18 hrs Time Interval = 1 min Runoff Volume = 3,625 cuft Drainage Area = 0.29 ac Curve Number = 74.00 Tc Method = User Time of Conc. (Tc) = 13.0 min Total Rainfall = 6.37 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 0.942 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 Proposed (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1B-U Woods C Hyd. No. 16 Hydrograph Type = NRCS Runoff Peak Flow = 1.787 cfs Storm Frequency = 10-yr Time to Peak = 12.18 hrs Time Interval = 1 min Runoff Volume = 6,871 cuft Drainage Area = 0.62 ac Curve Number = 70.00 Tc Method = User Time of Conc. (Tc) = 13.0 min Total Rainfall = 6.37 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 1.787 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 (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1B-U Impervious Hyd. No. 17 Hydrograph Type = NRCS Runoff Peak Flow = 6.642 cfs Storm Frequency = 10-yr Time to Peak = 12.12 hrs Time Interval = 1 min Runoff Volume = 25,607 cuft Drainage Area = 1.18 ac Curve Number = 98.00 Tc Method = User Time of Conc. (Tc) = 7.0 min Total Rainfall = 6.37 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 6.642 cfs 7 6 5 4 Q (cfs) 3 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 Proposed (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1B-U Hyd. No. 18 Hydrograph Type = Junction Peak Flow = 9.155 cfs Storm Frequency = 10-yr Time to Peak = 12.13 hrs Time Interval = 1 min Hydrograph Volume = 36,104 cuft Inflow Hydrographs = 15, 16, 17 Total Contrib. Area = 2.09 ac Qp = 9.155 cfs 10 9 8 7 6 Q (cfs) 5 4 3 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-1B-U Open Space C PR-1B-U Woods C PR-1B-U Impervious PR-1B-U

Hydrograph Report File: Eagle Rock Proposed (Future).hys Hydrology Studio v 3.0.0.39 10-21-2025 PR-1B-U Open Space C Hyd. No. 15 Hydrograph Type = NRCS Runoff Peak Flow = 1.349 cfs Storm Frequency = 25-yr Time to Peak = 12.18 hrs Time Interval = 1 min Runoff Volume = 5,225 cuft Drainage Area = 0.29 ac Curve Number = 74.00 Tc Method = User Time of Conc. (Tc) = 13.0 min Total Rainfall = 8.13 in Design Storm = NOAA-D Storm Duration = 24 hrs Shape Factor = 484 Qp = 1.349 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)