Stochastic Modelling of Reservoir Sedimentation in a Semi-Arid Watershed

TLDR: In this article, a dynamic model of the reservoir was set up and used to estimate past water and sediment inflows (period 1990-2010) based on data recorded by the dam operator and measurements at a gauging station located downstream of the lake.

Abstract: Sedimentation in large reservoirs is a major concern in semi-arid regions characterized by severe seasonal water scarcity. As a contribution to improved sediment management, this study analyses the real case of the reservoir of Sidi Yacoub in the north of Algeria. First, a dynamic model of the reservoir was set up and used to estimate past water and sediment inflows (period 1990–2010) based on data recorded by the dam operator and measurements at a gauging station located downstream of the reservoir. Second, in a stochastic framework using the statistical characteristics of inflow and outflow discharges, a projection of future sedimentation was performed until 2030, assuming stationarity of the statistical distributions. Third, the model was used to investigate the influence of possible climate change and to quantify the positive effects of soil conservation measures upstream.

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Digital model of the pre-impoundment topography
(Courtesy of Marc Binard - ULg)
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Digital modes of the reservoir bathymetry as surveyed in 2004
(Courtesy of Marc Binard - ULg)

Difference between the pre-impoundment topography
and the bathymetry surveyed in 2004
(Courtesy to Marc Binard - ULg)