Subsurface drainage of sloping lands

The problem of groundwater flow over sloping beds is investigated on the assumption that the streamlines are parallel to the stoping bed instead of being horizontal. The sloping bed is bounded below by an impermeable sublayer, and with the upper surface free. In this case, the resulting equation is the non-linear Boussinesq equation incorporating the slope factor. We solve this equation by a modified boundary integral procedure known as the Green element method (GEM). This numerical technique resolves the non-linearity of the governing equation efficiently and straightforwardly. Comparison of the results obtained herewith with those available in literature shows good agreement, and confirms that for a majority of practical cases, GEM simulation can be considered to be satisfactory. (C) 1999 Elsevier Science Ltd. All rights reserved.