Over the last 12 years water-spreading weirs have been introduced and improved as a new rehabilitation technique for degraded dry valleys in Burkina Faso, Niger and Chad. They complement the previously available, proven rehabilitation measures for drainage basins. As a result, a set of measures is now available for the future stabilisation of such basins – from the plateaus to the slopes to the valley floor. Water-spreading weirs are an additional, economical and effective water management option for valleys, where they supplement retention basins, small impoundment dams and microweirs as means of intensifying agricultural production in the valleys. In contrast to other techniques, water-spreading weirs are especially well-suited for the large-scale rehabilitation of wide and shallow dry valleys that have been seriously degraded and in which severe gully erosion prevents the regular flooding that would normally be typical there.

Water-spreading weirs alter the basic runoff and sedimentation processes in the valley. Specific adaptation to the various alterations of natural processes and agricultural optimisation of the water-spreading weirs are frequently beyond the scope of a single construction campaign, and subsequent adaptations may be required. In constructing water-spreading weirs, the first step is to identify basically suitable valleys in a region and inform the respective villages, communities and technical services about the possibilities and prerequisites for rehabilitation. Interested communities then submit a written request to the project in charge, which is examined by an approval committee. The socioeconomic conditions and structures in the valley and the willingness of the local people to cooperate are assessed in the subsequent feasibility study. Then the basic construction parameters are defined and the anticipated costs are estimated in a preliminary technical study. The information delivered by these studies provides the basis for the final approval of the construction.