Application of a gis based distributed hydrological system to the large river basin

The National Oceanic and Atmospheric Administration has developed a river forecast system for the entire Nile basin. The primary goal was to provide forecasts of the inflow into the High Aswan Dam (HAD) with as much lead time as technically feasible. The forecast system has a grid point structure with the sub-basins represented as connected grid points. Connectivity of the grid points is determined based on both stream network definition and elevation data by using the Geographic Information System. The inputs to the distributed hydrological system are the gridded rainfall and potential evaporation. The initial operational version of the MFS system was installed in 1992 in Cairo, Egypt. Since then, various enhanced or improved versions have been installed with the latest system installed in July 1995. The main output of the system is an expected inflow into the HAD for three-five months ahead. However, the system provides additional products, such as, short-term and long-term expected hydrographs at different outlets of the Nile, high resolution daily precipitation, evaporation, and soil moisture conditions, climatological precipitation and potential evaporation data and their statistics.