Analytical-Numerical Solution for Seepage along an Earth Canal Disconnected from the Shallow Aquifer

To have a better understanding of seepage from the canal beds, authors developed a new infiltration method to analyze seepage beneath canal beds during ponding tests. This is distinct from Green-Ampt method for infiltration on a uniform unsaturated zone and with a constant head in a ponding area. An analytical-numerical equation was derived to represent the seepage flow based on Darcy's law and Romos' method. Five ponding tests conducted on the selected sections of Franklin Canal in El Paso, Texas were analyzed using the proposed methods. The comparison between analytical solution and other ponding test observation indicated that analytical-numerical solution gives a good approximation of seepage losses. The annual canal seepage losses vary spatially depending on hydraulic conditions in the canal, ranging from 86,245˜299,467 m³/km for low flow in the canal, to 177,184˜564,875 m³/km for high flow, which provide a great potential for water conservation.