ABSTRACT: The research project reported in this paper study the effects of channel improvement on the flood wave that propagates along the main stream. The channel improvement affects different flood criteria such as the total volume of flood, the time to peak discharge, peak discharge, total sediment volume, and peak sediment graph. The flood event is simulated using the well known hydrological model, WASHMO which uses a finite difference method for modelling unsteady free surface water flow and also simulate rapidly varied flow over common hydraulic structures (Elhanafy 1999). A series of simulations are carried out and compared with previous study on a specified watershed in the Northern coast of Egypt. The positive effects of channel improvement are promising and could be used before the design of any control actions. This indirect method could be used to mitigate the flood disaster effects. This model could be used as a stepping stone for different purposes including cost minimization of protection works, increasing the live span of the water structures along the main stream, minimization of the erosion near the piers of bridges and culverts, and seepage minimization.