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.

Problem
A circular concrete sewer pipe with coefficient of roughness n = 0.013 is 1.60 m in diameter and flowing half-full has a slope of 4 m per 5 km. Compute the discharge on the sewer pipe in cubic meter per second.