Runoff Coefficient (C)
This Coefficient allows for the quantity of water which runoff a particular type of surfacing into a drainage system, and discount the quantity of water which will soak into or through the surfacing.
Typical values are given below;
| Typical Runoff Coefficients | |
| Land Use | |
| Cultivated Land | 0.1 |
| Pasture | 0.2 |
| Forest | 0.1 |
| Typical Residential Lot | 0.3 |
| Typical Industrial Lot | 0.85 |
| Concrete | 1 |
| New Asphalt | 0.85 |
| Old Asphalt | 0.95 |
| Block Paving (Cemet Joints) | 0.8 |
| Block Paving (Open Joints) | 0.6 |
| Roof | 1 |
Related Spreadsheets from CivilWeb;
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Manning Open Channel Design Spreadsheet
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Runoff Calculator Spreadsheet
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Full Drainage Design Suite
Full drainage design suite (50% Discount) including 7 spreadsheets;
- Colebrook White Pipe Design
- Manning Pipe Design
- Manning Open Channel Design
- Linear Drainage Design
- Runoff Calculator
- Attenuation Design
- Soakaway Design