Solution of water-table and anisotropic flow problems by using the strongly implicit procedure

The use of the strongly implicit procedure (SIP) with an additional iteration parameter, β, to scale the residual vector is advantageous to the solution of some ground-waterflow problems. For steady-state water-table problems plagued by excessive elimination of grid blocks during the iteration process, selection of β<1 can be effective in limiting the deletion of blocks to a reasonable number. Also, a linear problem characterized by large anisotropy and layers of contrasting hydraulic conductivity was solved more efficiently with β=1.5. Effective values of β are generally in the range 0<β<2 and are easily determined by trial. Use of a β parameter in the SIP algorithm provides an effective solution technique for a class of ground-water-flow problems that previously was burdened by significant computational difficulty.