2025 12 19 Stormwater Report Rev 1

Time of Concentration Calculations Project #: 24-170 Pre-Development Project: The Estate Post-Development County: Essex Drainage Area: DA-1 Sheet Flow Segment 1 Segment 2 Segment 3 Surface Description (Table 3-1) Grass, Dense Grasses Grass, Dense Grasses Manning's Roughness Coeff., n (Table 3-1) 0.24 0.24 - Flow Length, L (total ≤ 100 ft) 20 80 Two-Year 24-Hour Rainfall, P2 (CA) 3.47 3.47 3.47 Two-Year 24-Hour Rainfall, P2 (FP) 4.09 4.09 4.09 Land Slope, s (ft/ft) 0.025 0.05 Tt (CA) 3.5 7.9 - 11.4 Tt (FP) 3.2 7.3 - 10.5 Shallow Concentrated Flow Segment 1 Segment 2 Segment 3 Surface Description Unpaved paved paved Flow Length, L 70 340 120 Watercourse Slope, s (ft/ft) 0.05 0.05 0.025 Average Velocity 3.6 4.6 3.2 Tt 0.3 1.2 0.6 2.2 Channel Flow Segment 1 Segment 2 Segment 3 Cross Sectional Flow Area, a Wetted Perimeter, Pw Hydraulic Radius, r - - - Channel Slope, s (ft/ft) Manning's Roughness Description Manning's Roughness - - - Velocity - - - Flow Length Tt -

- - Velocity - - - Flow Length Tt - - - 0.0 Current Adjusted (CA) 13.6 Future Projected (FP) 12.7