Surface water leakage, sedimentation and evaporation in arid regions: A case study of the Gargar dam, Algeria

This study was carried out in order to assess the total capacity loss in Gargar dam, third-largest in Algeria, due to the mudding of the reservoir, intense evaporation and water leaks. We analysed the variation in leakage as a function of the reservoir level, and quantify losses due to leaks, sedimentation and evaporation. We relied on site visits and data obtained from the Algerian Agency for Dams and Transfers to assess the leakage volume; reservoir level; sedimentation and evaporation levels for the period 1988–2015. We present an updated report of this problem through the dam. We estimated total average losses of 23 million m3·year−1 for the period 1988–2015, made up of leakage (0.3 million m3·year−1), evaporation (18 million m3·year−1) and dead storage for 4.6 million m3·year−1. However, total losses for 2004 were estimated at 113.9 million m3, which increased to the alarming value of 166.8 million m3 in 2015. We suggest improving the waterproofness by a concrete screen, and reducing mudding and evaporation by reforestation, to increase the storage capacity of the dam.