Flood Risks Assessment Using Remote Sensing and Geographic Information Systems in Omdurman Area

Abstract

Modern techniques of Remote Sensing (RS) provide tremendous potentialities for monitoring dynamic changes in large surface water bodies, allowing extracting hydrological parameters, and modelling water balance. Geospatial techniques such as Geographical Information Systems (GIS) together with Remote Sensing help in locating suitable water discharge and / or harvesting drainage sites located in recent years. This volume of water can be useful for the construction of a dam (Hafir), or a basin in the study area. In addition, this can be an effective source for providing water for agriculture and pasture in the areas, which are far from the permanent water bodies such as the Nile. Over the past century, Khartoum State has become an increasingly urbanized region. The changes in land use associated with urban development affect flooding zones in many ways; removing vegetation and soil, grading the land surface, and constructing drainage networks. This had increased runoff to streams resulting from rainfall every season. Consequently, the peak discharge, volume, and frequency of floods increase in nearby streams or rivers; in particular, the White Nile River. The main objective of the study is to model the negative impact of the floods in study area by density mathematical model to predict flood, providing a database to manage flood Risks within the Study Area. RS and GIS have been used to investigate the best water collection area derived from Digital Elevation Model. The areas affected by the flood were interpolated from the satellite imagery (Landsat system) and from the Nile River level data, rain and flood. Mathematical models have been generate to predict the areas that are subjected to be inundated by rainfall and the water level of the Nile. Rainfall affects more than other factors on the study area. The contribution of rainfall in floods within the study area is about 4 times that of River Nile ‎water level‎.