Manual

A P P E N D I X C
Manning Strickler Coefficient Table
Consistency of channel wall M in m1/3/s k in mm
smooth
glass, PMMA, polished metal surfaces > 100 0...0.003
plastic (PVC, PE)
new steel plate with protective coating;
smoothened cement plaster
≥ 100
0.05
0.03...0.06
moderately rough
asphalt coated steel plate;
concrete from steel or vacuum formwork, no joints, carefully
smoothened;
planed wood, joint-free, new;
asbestos cement, new
90...100 0.1...0.3
smoothened concrete, smooth finish
planed wood, well-joint
85...90 0.4
0.6
concrete, good formwork, high cement contents 80 0.8
rough
non-planed wood; concrete pipes 75 1.5
hard-burned bricks, carefully joint;
well-manufactured ashlar facing;
concrete from joint-free wooden formwork
70...75 1.5...2.0
rolling-cast asphalt finish 70 2
well-manufactured ashlar masonry;
moderately incrusted steel pipes;
non-finished concrete, wooden formwork;
squared stones; old and swelled wood;
cement walls
65...70 3
non-finished concrete; old wooden formwork;
brickwork, no joints, finished;
quarrystone walls; less accurate
soil material, smooth (fine-grained)
60 6
Note: Rougher surfaces are difficult to measure under hydraulic conditions and, therefore, have not been included.