Manning's Roughness Coefficient
Manning's roughness coefficient values for some common materials
Sponsored Links
Manning's roughness coefficient values are used in the Manning's formula for flow calculation in open flow channels. Coefficients for some common used surface materials can be found in the table below:
| Surface Material | Manning's Roughness Coefficient - n - |
| Asbestos cement | 0.011 |
| Asphalt | 0.016 |
| Brass | 0.011 |
| Brickwork | 0.015 |
| Cast-iron, new | 0.012 |
| Clay tile | 0.014 |
| Concrete - steel forms | 0.011 |
| Concrete - finished | 0.012 |
| Concrete - wooden forms | 0.015 |
| Concrete - centrifugally spun | 0.013 |
| Copper | 0.011 |
| Corrugated metal | 0.022 |
| Earth | 0.025 |
| Earth channel - clean | 0.022 |
| Earth channel - gravelly | 0.025 |
| Earth channel - weedy | 0.030 |
| Earth channel - stony, cobbles | 0.035 |
| Floodplains - pasture, farmland | 0.035 |
| Floodplains - light brush | 0.050 |
| Floodplains - heavy brush | 0.075 |
| Floodplains - trees | 0.15 |
| Galvanized iron | 0.016 |
| Glass | 0.010 |
| Gravel | 0.029 |
| Lead | 0.011 |
| Masonry | 0.025 |
| Metal - corrugated | 0.022 |
| Natural streams - clean and straight | 0.030 |
| Natural streams - major rivers | 0.035 |
| Natural streams - sluggish with deep pools | 0.040 |
| Plastic | 0.009 |
| Polyethylene PE - Corrugated with smooth inner walls | 0.009 - 0.015 |
| Polyethylene PE - Corrugated with corrugated inner walls | 0.018 - 0.025 |
| Polyvinyl Chloride PVC - with smooth inner walls | 0.009 - 0.011 |
| Steel - Coal-tar enamel | 0.010 |
| Steel - smooth | 0.012 |
| Steel - New unlined | 0.011 |
| Steel - Riveted | 0.019 |
| Wood - planed | 0.012 |
| Wood - unplaned | 0.013 |
| Wood stave | 0.012 |
Sponsored Links
Sponsored Links
Engineering ToolBox - SketchUp Edition - Online 3D modeling!
Engineering ToolBox - SketchUp Edition - enabled for use with the amazing, fun and free Google SketchUp.
Search the ToolBox
© The Engineering ToolBox 2005
9 12 8
