Manning's n Tables Manning's n values for Channels, Closed Conduits Flowing Partially Full, and Corrugated Metal Pipes.
Manning's n Table TxDOT Manning's n Table
Estimates discharge in US customary units from
Q = (1.0/n)*A*(A/P)^(2/3)*S^(1/2)
where:
Q is the discharge (cubic meters per second)
n is Manning's roughness coefficient (read from table)
A is cross sectional flow area (square meters)
P is wetted perimeter (meters)
S is friction slope (often the channel slope is substituted)
----- INPUT VALUES -----
| Manning's n | Look-Up | |
| Flow Area | (m^2) | |
| Perimeter | (m) | |
| Slope | (m/m) | |
----- COMPUTED RESULTS -----