Sediment deposits at dams put long-term water supply at risk in Morocco

Morocco is one of the countries most badly impacted by erosion. Each year, vast storage capacities are lost due to sedimentation at Lalla Taberkoust dam, which provides the majority of the drinking water for the Marrakesh urban region and field irrigation in the Tensift basin.

Wüstenregion in Marokko

Lalla Takerkoust dam in Morocco: Example of extreme sedimentation © H. Schüttrumpf

In addition, the groundwater deficit rises each year. The water table at “nappe de Haouz” currently drops by up to one metre each year. Which is why the use of dams is of key importance for the whole country in terms of drinking water supply and the provision of irrigation water for agriculture. The aim of the Moroccan-German project, which finished at the end of 2014 after three years, was to contribute to a reduction of these problems and hence to a sustainable water resources management.

The project theoretically examined several processes to reduce sediment inflow and sediment deposits at dams. One process of continuous sediment removal, which ensures continuous sediment flow and as such avoids dam sedimentation, is particularly interesting. The suitability of this and alternative processes is being discussed in detail for reservoirs in Morocco.

Special geographic features in Morocco

Sedimentation at this level occurs only in Morocco and in a handful of other countries across the world. A technology of continuous sediment removal cannot be developed based on the conditions in Germany. As a result, it is important to define the requirements that the technology must meet taking account of the conditions in Morocco.

Special results and successes of the measure

An overview of the sedimentation and de-sedimentation technologies at Moroccan and German dams was compiled.

New technologies for continuous sediment removal in desert regions were investigated and first applications prepared. The hydrological, sedimentological, granulometric and legal framework conditions for a sediment management at dams in Morocco were determined.

Recommendations for a modern use of technology in Morocco and Germany were prepared.

Contact

Dr Oliver Dilly
DLR Project Management Agency | International Bureau
Tel.: +49 228 3821 -1470

Prof Dr-Ing Holger Schüttrumpf
RWTH Aachen
Tel.: +49 241 80 -25262

Prof Ali Hammani
Institut Agronomique et Vétérinaire Hassan II, Rabat