Grand Ethiopian Renaissance Dam years of future drought, if the countries can reach a compromise. The dam will retain silt. It will thus increase the useful lifetime of dams in Sudan – such as the Roseires Dam, the Sennar Dam and the Merowe Dam – and of the Aswan High Dam in Egypt. The beneficial and harmful effects of flood control would affect the Sudanese portion of the Blue Nile, just as it would affect the Ethiopian part of the Blue Nile valley downstream of the dam. Specifically, the GERD would reduce seasonal flooding of the plains surrounding the reservoir of the Roseires Dam
Aswan Dam soil surface over the years. Since most of the farmland did not have proper subsurface drainage to lower the groundwater table, salinization gradually affected crop yields. Drainage through sub-surface drains and drainage channels is essential to prevent a deterioration of crop yields from soil salinization and waterlogging. By 2003, more than 2.0 million have been equipped with a subsurface drainage system at a cost from 1973 to 2002 of about $3.1 billion. Contrary to many predictions made prior to the Aswan High Dam construction and publications that followed, that the prevalence of schistosomiasis (bilharzia) would increase, it did not. This