The implication of climate change and precipitation variability on sedimentation deposits in Algerian dams
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ORIGINAL PAPER
The implication of climate change and precipitation variability on sedimentation deposits in Algerian dams Medjber Abdellah 1 & Hadjem Mohamed 1 & Daoud Farouk 1 Received: 6 May 2018 / Accepted: 23 November 2018 # Saudi Society for Geosciences 2018
Abstract Water erosion represents a major problem in Algeria. The country loses 20 million m3 of water per year due to sediment deposits in dam reservoirs, which is related to the process of erosion in watersheds. In recent years, Algeria has seen a decrease in its average rainfall, due to the effects of climate change on water resources which have resulted in extreme droughts all over the country. The erosion in the watersheds is generally high, and the quantities of transported sediments are extremely variables. In this study, we analyzed the influence of climate change on the rate of water erosion in the watersheds through the measurement of precipitation during different time periods. Water erosion was evaluated at 21 dam reservoirs located in the northern part of the country using bathymetric surveys. Hypsometric analysis revealed that studied watersheds present several geomorphic stages: youth, mature, and old stages. The results of the study showed the influence of precipitations and its variation over time on water erosion at the studied watersheds. A strong relationship was found between average sedimentation rate and mean inter-annual precipitation. Keywords Climate change . Dam . Precipitation . Sedimentation . Water erosion . Watershed
Introduction Water has always played a vital role in human societies. To manage their water resources, many countries have built water reservoirs, using dams, for development projects, growth, and poverty eradication. However, many dams encounter issues due to sedimentation as a result of water erosion. According to a report of the WCD (World Commission on Dams, 2000), the world’s reservoirs are currently losing their storage capacity to sedimentation at an estimated rate of 0.5– 1% per year. This implies that, if without necessary measures to reduce sediment deposition, around 25% of the world’s current water storage capacity may be lost in the coming 25 to 50 years (Ran et al. 2013). Sedimentation continues to be one of the most important threats to river eco-systems. A study was done on the world’s 145 major rivers with consistency long-term sediment records, and the results show that about
* Medjber Abdellah [email protected] 1
Department of Hydraulics and Civil Engineering, Dr Moulay Tahar University, Saida, Algeria
50% of the rivers have statistically a significantly downward water flow trend due to sedimentation (Colleta et al. 2018). The capacity of the dams and barrages in Algeria has been continuously reducing due to rapid soil erosion and subsequent increase in sediment loads in dam reservoirs. The country’s dams have been hit hard by the phenomenon of sedimentation deposit, which, according to the latest UNESCO report, has already reached 1.1 billion m3 (Remini et al. 2009). Annually, betw
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