Effect of Grand Ethiopian Renaissance Dam (GERD) on the Life Span of Aswan Reservoir

Abstract
About 98 percent of the annual sediments are carried by the Nile during the flood season. Most of these sediments are eroded from the Blue Nile high lands (about 82%). Since the grand Ethiopian renaissance dam (GERD) start to store the flooding water and sediment during this year, then sediment that will be stored by this dam will effect strongly on the life span of Aswan high dam reservoir (AHDR). The objective of this research is to determine the life span of AHDR with respect to the new regulation of the Nile Basin's water and sediment discharge, after the construction of GERD.
Volume of sediment for the Blue Nile basin was determined by using remote sensing techniques and by the aid of hydrological model, watershed storm hydrograph model (WASHMO) that was established by Andy Ward 1986. Hydrological parameters for 15 sub basin were extracted from digital elevation model (DEM) of Shuttle Topographic Radar Mission. Other parameters that concerns rainfall, soil characteristics and land covers were collected from Atlas of the Blue Nile Basin (Yilma and Awulachew, 2009) and inserted in the mentioned model in order to determine sediment yield from the Blue Nile Watershed.
Life Span of Aswan High Dam Reservoir (AHDR) was studied by many researchers during the last three decades of the last century. There results obtained on the basis of different studies and according to many approaches. It ranges from 362 years to 365 years (Shalash,1980, Makary;1982 and Moussa;1985). According to the volume of sediment that will be retained by grand Ethiopian renaissance dam and found to be 57.50 X 106 m3 for one storm/year .Then the life span of Aswan Reservoir can be estimated according to the establishment of this dam.