Abstract:
Flood can be defined as the temporary covering of land by water which is not normally covered by water. Flash floods are caused by large amounts of runoff due to short duration and high intensity rainfall. Flooding is one of the most important types of disasters have provoked extended damages over the last centuries. Remote Sensing techniques provide safe and cost-effective tools for monitoring, mapping and assessing the evolution and damages caused by flood events. The temporal and spatial availability of SAR (Synthetic Aperture Radar) data has been increasing, and flood detection is candidate to be a very popular application area of SAR data. The use of sentinel 1 image is important since it can identify flooded areas easily and using binarisation method extraction of features is easy based on their brightness. Preprocessing of sentinel 1 image include radiometric correction and geometric correction. The software used for this research include Erdas, ENVI, SNAP, and ArcGIS. The data include sentinel 1 image, DEM and Rainfall data. The objectives of this study are (a)to identify land cover types in the study area, (b) To determine the extent of Tana river before flooding and after flooding, (c) To determine effects of flooding based on land use land cover. The findings of this study shows that the land cover types in the area were water, vegetation, built up, other vegetation and bare land and the extend of floods were more in 2018 than in 2017 and 2016. Most areas affected were areas with low elevation of between 6 to 32.