Quickly calculate the Manning flow velocity for open channels, rivers, and culverts with our easy-to-use online tool. Accurately determine water speed essential for hydraulic design, stormwater management, and civil engineering projects.
Formula:
The Manning's flow velocity formula is:
V = (k / n) * R(2/3) * S(1/2)
Where:
- V = Flow Velocity (m/s or ft/s)
- k = Unit System Constant (1.0 for SI, 1.49 for US Customary)
- n = Manning's Roughness Coefficient (unitless)
- R = Hydraulic Radius (m or ft)
- S = Channel Bed Slope (unitless, m/m or ft/ft)