Koudiat El Mahcha Storage Dam

The Annaba region of northeastern Algeria faces a persistent storage deficit, with agricultural and urban demand outpacing existing infrastructure. Koudiat El Mahcha was conceived to close part of that gap from an unconventional source: treated effluent from the Annaba wastewater treatment plant, stored and returned to productive use.

Libanconsult delivered the detailed design of the dam and its transmission line for the Agence Nationale des Barrages et Transferts (ANBT) between 2017 and 2022, across ten dedicated missions from alternatives definition through to tender documentation.

The dam is a rockfill structure with a clay core, 29.8 m at maximum height and 658 m along the crest, impounding a 13 Hm3 reservoir. A 35 km transmission line conveys treated water from the Annaba WWTP to the reservoir via pump stations and break-pressure tanks. The design package covered hydrological, geological, seismic, hydraulic and geotechnical studies, environmental impact assessment, profitability and dam-break analysis, bill of quantities and full tender documents, with the alignment integrated into existing irrigation and agricultural reuse networks.

The result is a tender-ready scheme converting Annaba's treated effluent into 13 Hm3 of usable storage in a water-stressed catchment.