2023 06 Drainage Statement

Date: 7/6/2023 Project: Proposed Popeyes & Sonic Restaurant Project No: 1021-99-025 1904 Main Street, Lake Como, NJ 07719 Calculated By: DG (732) 974-0198 Checked By: MB Worksheet 3: Time of Concentration (T c ) Calculations Land Condition: Proposed Drainage Area: Site • Sheet Flow : AB BC CD Short Grass, Short Grass, 1. Surface Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prairie . Prairie Smooth Surfaces 2. Manning's Roughness Coefficient, n . . . . . . . . . . . . . . . . . . . .0.15 .. 0.15 0.011 3. Flow Length, L { total L ≤ 100 ft } . . . . . . . . . . . . . . . . . . . . .13.0 . . ft 24.0 ft 30.0 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 0.126 0.024 ft/ft 0.027 ft/ft 0.007 (n L ) 0.8 6. Travel Time, T t = . . . . . . . . . . . . . . . .0.015 . . . . .hr

. . . . . . .0.015 . . . . .hr .. + 0.047 hr + 0.007 hr = 0.068 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 : DE EF FG 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.027 .. ft/ft 0.081 ft/ft 0.046 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 =

ghness Coefficient, n . . . . . . . . . . . . . . . . . . . 0.013 .. 0.013 0.013 1.49 r 2/3 s 1/2 19. Velocity, V = . . . . . . . . . . . . . . . . . .7.47 . . . ft/s 12.95 ft/s 11.32 ft/s n 20. Flow Length, L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.0.... 55.0 39.0 21. Travel Time, T t = L . . . . . . . . . . . . . . . .0.003 . . . . .hr . . .+ . . . 0.001 . . . . . hr . . . .+. . 0.001 hr = 0.006 hr 3600 V 22. Watershed or subarea Time of Concentration, T c { add T t in steps 6, 11 and 21 } . . . . . . . . . . . . . . . . . . . . . . . . . 0.074 hr 4.4 min 1