Canal Design: Optimal Cross‐Sections

Abstract

Canal cross‐section designs for uniform flows are contrasted and compared by using nondimensional shape parameters. The basic relations among the cross‐section shapes and design variables (the wetted perimeter, the water depth, the water surface width, the cross‐sectional area, the lining volume, the excavation volume, etc.) are exposed. These relations are used to uncover robust rules that can determine optimal canal designs for elementary problems, directly from flow information such as capacity, velocity, slope, and roughness. For problems involving complex limits and economics, the relations are combined with optimization methods to solve for the economically optimal cross sections. The possible cross sections are parameterized by at most two variables, so the calculations do not require the use of sophisticated optimization methods or large computers.