The WellDrain computer program calculates the drainage discharge by wells, hydraulic head, hydraulic conductivity, or spacing between pumped wells (open dug wells, tubewells, vertical drainage) and shows the curvature of the watertable (water-table). The computations are needed for the design of subsurface drainage systems by open wells or tube-wells of rainfed or irrigated agricultural land and soil salinity control. The wells may be partially or fully penetrating the aquifer.