from "Chow, V.T., Maidment, D.R., Mays, L.W., 1988, Applied Hydrology: New York, McGraw- Hill."

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 = (1.49/n)*A*(A/P)^(2/3)*S^(1/2)

where:

Q is the discharge (cubic feet per second)

n is Manning's roughness coefficient (read from table)

A is cross sectional flow area (square feet)

P is wetted perimeter (feet)

S is friction slope (often the channel slope is substituted)