Abhatoo - Centre Nationale de Documentation

The Gharb plain in Morocco faces both problems of excess winter rainfall and salinity hazards due to a shallow, permanent and saline groundwater. A large area of 80.000 ha out of a total planned area of 200.000 ha has been equipped with subsurface drains. This system has been designed without any local references and has encountered several maintenance problems, mainly caused by high drain depths.
A pilot experiment was installed to provide drainage design criteria appropriate to the local conditions. The main experimental results, based on water and salinity balance and on groundwater flow, are presented in this paper. They show that in the Gharb plain, drainage systems should be designed from winter drainage design criteria. This paper also emphasises that particular attention be paid to surface drainage, which removes about 40% of the excess water.