This study develops a response-based hydrologic model for long-term (continuous) rainfall-runoff simulations over the catchment areas of big rivers. The model overcomes the typical difficulties in estimating infiltration and evapotranspiration parameters using a modified version of the Soil Conservation Service curve number SCS-CN method. In addition, the model simulates the surface and groundwater hydrograph components using the response unit-hydrograph approach instead of using a linear reservoir routing approach for routing surface and groundwater to the basin outlet. The unit-responses are Geographic Information Systems (GIS)-pre-calculated on a semi-distributed short-term basis and applied in the simulation in every time step. The unit responses are based on the time-area technique that can better simulate the real routing behavior of the basin. The model is less sensitive to groundwater infiltration parameters since groundwater is actually controlled by the surface component and not the opposite. For that reason, the model is called the SCHydro model (Surface Controlled Hydrologic model). The model is tested on the upper Blue Nile catchment area using 28 years daily river flow data set for calibration and validation. The results show that SCHydro model can simulate the long-term transforming behavior of the upper Blue Nile basin. Our initial assessment of the model indicates that the model is a promising tool for long-term river flow simulations, especially for long-term forecasting purposes due to its stability in performing the water balance.

The fact that Egypt falls within the arid and semi-arid areas, makes it always vulnerable to sudden storms, which have increased significantly during the past ten years. Climate change is one of the factors that cause the increasing of the sudden storms frequency, intensity and expansion to cover new areas. During three days, from November 11 to 13, 2021, a severe storm hit the city of Aswan and its suburbs, leaving behind extensive property damage and loss of life. Where heavy rains, fell in a short time, on the Eastern Desert Mountains led to torrential rains (flash flood) that flowed to the plains through the paths of the valleys, causing severe damage to several villages, which are located in the hydrologically active valleys (Al-Heita, Al-Kimab, Umm Buirat and Abu Al-Rish Qebli). In this paper, the November 2021 storm will be analyzed using Global Precipitation Measurement (GPM) data, with temporal and special resolution of 30 minutes and 0.1° respectively. The data will give a distribution of the storm for each 1 hour during the storm for three days. The amount of water and its velocity will also be simulated using the (HEC-HMS) hydrological model. In addition, the (HEC-RAC) model is used in order to simulate the distribution and expansion of the flood during the storm time step. The results provide an actual simulation of what happened during the 2021 storm. In addition, this model is applied again with the highest values to produce the worst scenario. The final part of this paper highlights the value of this model as a supportive tool for urban planning to achieve sustainability. So, both results of the simulation and the worst scenario were compared to the development plan of the study area. Then, the suitable planning recommendations were accordingly suggested for the areas at risk to ensure sustainable future development.