Analysis of Canal Seepage to Interceptor Drain

No solution for the problem of seepage from trapezoidal channels in homogenous and isotropic material to an interceptor drain and the main drainage at finite distance is available so far. This general problem is solved exactly by the use of conformal mapping. Equations for seepage discharge to the interceptor drain and the main drainage and shape of free surface are given. These equations are solved numerically. The results are given in the form of dimensionless curves. The analysis indicates that the effect of lowering of phreatic surface by provision of interceptor drain extends to a considerable distance on either side of the drain. The location of the drain farther away from the canal results in greater lowering of free surface beyond the drain although this results in a slight rise in the elevation of free surface between the canal and the drain.