Analysis of Risks and Impacts of Flooding with Satellite Remote Sensing

Abstract

In recent times there have been extreme climatic conditions due to climate change. As a result of this, the intensity of rainfall has increased tremendously causing flooding in many areas and countries worldwide. It is therefore prudent that such a natural hazard is addressed in a way to reduce the impact it causes on people and the environment. Adequate geographic information on hazards and areas vulnerable to hazards is required to be able to prepare for disasters.  Flood  vulnerability  mapping  is  fundamental  in  flood  risk  management because  it  identifies areas vulnerable  to  flood disaster.   In this study, efforts were made to provide information that can assist government agencies in determining types of land use and land cover types that may be affected at different levels of flood risk inundation in event of flood disaster. Landsat-7ETM+ of 2012 was classified. Shuttle Radar Topography Mission (SRTM) image of 2000 was resampled to 28.5m resolution of Landsat image and used to generate the Digital Elevation Model (DEM) and slope gradient of the study area.  The DEM and slope gradient map were reclassified and combined through series of analysis to generate different levels of flood risk. The different land cover classes were overlaid with the flood risk map in order to know the land cover type that will be mostly affected in the event of flood disaster. It is recommended among others that communities that fall within the very high risk flood inundation should be identified and possibly relocated to higher ground elevation.

Keywords: Flood, Satellite image, Risk, GIS and DEM