Automated rock size and roughness design iteration
Choose a roughness option (Blodgett–Bathurst recommended) and a design rock size option (Isbash recommended). Adjust depth and rock size safety factor to reach your target flow with a uniform rock size. Each time you change an input, the calculator repeats these steps: 1. Roughness is calculated from design rock size. 2. The roughness value from the method you chose is copied into the roughness input. 3. Channel flow and required rock size are calculated. 4. Design rock size is adjusted. 5. Repeat until error in the design rock size is very small.
Basic calculator (no iteration)
Enter your desired roughness value. Ignore the design rock size input area.
Velocity check
High velocity implies that there was a large elevation drop that created such high specific energy. That energy can be lost quickly at expansions, bends, or obstructions. Verify that this is reasonable for the site.
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