ZB 22 13 2023 03 Drainage Statement

Date: 3/30/2023 Project: Proposed Popeyes & Sonic Restaurant Project No: 1021-99-025 1904 Main Street, Lake Como, NJ 07719 Calculated By: JD (732) 974-0198 Checked By: DG/MB Worksheet 3: Time of Concentration (T c ) Calculations Land Condition: Proposed Drainage Area: Site • Sheet Flow : AB BC Short Grass, Smooth 1. Surface Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prairie . Surfaces 2. Manning's Roughness Coefficient, n . . . . . . . . . . . . . . . . . . . .0.15 .. 0.011 3. Flow Length, L { total L ≤ 100 ft } . . . . . . . . . . . . . . . . . . . . .52.0 . . ft 32.0 ft 4. Two-Year 24-hour Rainfall, p 2 for . . .Essex County. . . . 3.44 in 3.44 in 3.44 in 5. Land Slope, s (ft/ft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft/ft 0.065 0.030 ft/ft 0.007 (n L ) 0.8 6. Travel Time, T t = . . . . . . . . . . . . . . . .0.058 . . . . .hr .. + 0.007 hr + 0.000 hr = 0.065 hr

. . . . .hr .. + 0.007 hr + 0.000 hr = 0.065 hr p 2 0.5 s 0.4 • Shallow Concentrated Flow : 7. Surface Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8. Flow Length, L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9. Watercourse Slope, s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10. Average velocity, V { see Figure 3.1) . . . . . . . . . . . . . . . . . . . . . . 11. Travel Time, T t = L . . . . . . . . . . . . . . . .0.000 . . . . .hr .. + 0.000 hr + 0.000 hr = 0.000 hr 3600 V • Channel Flow : CD DE EF 12. Pipe Diameter, D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 in 12 in 15 in 13. Cross-Sectional Flow Area, A . . . . . . . . . . . . . . . . . . . . . . . 0.785 .. sf 0.785 sf 1.227 sf 14. Wetted Perimeter, p w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 ft 3.1 ft 3.9 ft 15. Hydraulic Radius, r = A / p w . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 . ft 0.3 ft 0.3 ft 16. Channel Slope, s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.021 .. ft/ft 0.025 ft/ft 0.049 ft/ft 17. Pipe Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RCP RCP RCP 18. Manning's Roughness Coefficient, n . . . . . . . . . . . . . . . . . . . 0.013 .. 0.013 0.013 1.49 r 2/3 s 1/2 19. Velocity, V = . . . . . . . . . . . . . . . . . .6.59

0.013 0.013 1.49 r 2/3 s 1/2 19. Velocity, V = . . . . . . . . . . . . . . . . . .6.59 . . . ft/s 7.19 ft/s 11.68 ft/s n 20. Flow Length, L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.0.... 55.0 39.0 21. Travel Time, T t = L . . . . . . . . . . . . . . . .0.004 . . . . .hr . . .+ . . . 0.002 . . . . . hr . . . .+. . 0.001 hr = 0.007 hr 3600 V 22. Watershed or subarea Time of Concentration, T c { add T t in steps 6, 11 and 21 } . . . . . . . . . . . . . . . . . . . . . . . . . 0.072 hr 4.3 min 1