# Manning's Formula

**Problem**

A triangular shaped channel is to be designed to carry 700 L/s on a slope of 0.0001. Determine what vertex angle and depth of water over the vertex will be necessary to give a section with minimum perimeter, assuming the channel is made of timber, *n* = 0.012. Use Manning’s formula.

A. θ = 45°, h = 1.425 m |
C. θ = 45°, h = 2.125 m |

B. θ = 90°, h = 2.215 m |
D. θ = 90°, h = 1.215 m |