An Integrated Surface and Groundwater Flow Model for the Design and Operation of Drainage Systems

Abstract

In The Netherlands dense channel systems are present for land drainage. In periods with a shortage of water these systems often serve to supply water for agricultural purposes as well. Because of the double function of these channels it is very important that they are maintained properly. Weed control, for instance, is necessary to prevent waterlogging or flooding in the case of high discharges. Maintenance costs are a heavy burden for the local water authorities. The frequency of maintenance activities is usually determined by a rule of thumb. This may result in too much maintenance. On the other hand the frequency of maintenance may be too small giving a greater danger for flood damage or insufficient water supply. The situation is even more complicated because water levels vary during the year. For a good water management the water level in winter is generally kept low to allow a quick drainage, whereas the level is raised in spring to conserve water for dry periods in summer or to make subsurface irrigation possible.