Design of Minimum Seepage-Loss Nonpolygonal Canal Sections

Analytical solutions exist for the problem of determination of seepage loss from polygonal sections such as a triangle, a rectangle, and a trapezoid. In this investigation, seepage from circular and exponential sections has been calculated by a finite-difference-based numerical solution of the differential equation governing the seepage flow. The phreatic boundaries of the flow domain were described in terms of two parameters that are estimated by a minimization process. Such seepage computations were performed for a large number of independent dimensionless variables of the section geometry. Subjecting the computed seepage to regression analyses explicit equations for seepage loss from canals having circular and exponential cross sections have been obtained. Using these seepage-loss equations, the design variables for minimum seepage loss of circular and exponential canal sections have been obtained. The use of the design equations has been illustrated by design examples.