Typical Manning's n Values

Surface Material Manning's n
Asbestos cement0.011
Asphalt0.016
Brass0.011
Brick & mortar0.015
Canvas0.012
Ductile iron, new0.012
Clay tile0.014
Concrete (steel forms)0.011
Concrete (finished)0.012
Concrete (wood forms)0.015
Concrete (spun)0.013
Copper0.011
Corrugated metal0.022
Earth, smooth0.018
Earth (clean)0.022
Earth (gravelly)0.025
Earth (weedy)0.030
Earth (cobbles)0.035
Floodplain (pasture)0.035
Floodplain (light brush)0.050
Floodplain (heavy brush)0.075
Floodplain (trees)0.150
Galvanized iron0.016
Glass0.010

Standard Pipe Diameters

Standard Pipe D (m)
0.11
0.16
0.20
0.25
0.30
0.375
0.45
0.525
0.60
0.675
0.75
0.825
0.90
1.05
1.20
1.35
1.50
1.65