An efficient numerical method of two‐dimensional steady groundwater problems

The boundary integral equation method (BIEM) is shown to be an efficient and accurate numerical technique for solving problems of Darcy flow in porous media. The BIEM is combined with conformal transformation to the complex potential plane to solve free surface problems without iteration and with relatively few nodal points. Since the BIEM reduces the effective dimensions of the problem by one, the computer time varies approximately as the inverse square of the point spacing, whereas in finite element or finite difference methods the time varies approximately as the inverse of the fourth power of the point spacing. Two examples of the BIEM are presented herein. They are flow through an underdrained dam and a seawater intrusion problem.