Due toanthropogenic activities and climatic variability, floods have been raisedlately in several regions worldwide. The resulting impact of floods onenvironment is often harmful. This is particularly applicable to underdeveloped countries like Pakistan, the country which is known for dry climaticconditions, and it became known region for such natural hazards and calamities (A shakeel et al 2014) Remote Sensing has made substantialcontribution in flood monitoring and damage assessment that leads the disastermanagement authorities to contribute significantly High temporal resolutionplayed a major role in Remote Sensing data for flood monitoring to encounterthe cloud cover.(M Haq et all 2012).
Thecauses of these floods are related to a number of factors which play as a majorcontribution to the worsening of the flood disaster. These factors wereclassified into the following: geomorphological features, anthropogenicactivities (urban changes), network and catchment factors, and rainfall andclimatic changes factors. The climatic changes have a major impact on therainfall intensity and will appear more in the future (A Youssef et all 2015).
Accurateand current floodplain maps can be the most valuable tools for avoiding severesocial and economic losses from floods. Accurately updated floodplain maps alsoimprove public safety. Early identification of flood-prone properties duringemergencies allows public safety organizations to establish warning andevacuation priorities. Armed with definitive information, government agenciescan initiate corrective and remedial efforts before disaster strikes (Chapmanand Canaan, 2001). Flash flood in the cities led to high levelsof water in the streets and roads, causing manyproblemssuch as bridge collapse, building damage and traffic problems.
It is impossibleto avoidrisksof floods or prevent their occurrence, however it is plausible to work on thereduction of theireffectsand to reduce the losses which they may cause. Flash flood mapping to identifysites in high risk flood zones is one of the powerful tools for this purpose.Mapping flash flood will be beneficial to urban and infrastructure planners,risk managers and disaster response or emergency services during extreme andintense rainfall events (Ismail Elkhrachy 2015).Rivervalley human settlements will be most effected by floods due to dependence ofwater source and physical and social works. One effected floods will distributelife fabric for five to ten years. This in turn changes migration pattern andrelocation.
Advances in remote sensing technology and new satellite platformssuch as ALOS (Advanced Land Observation Satellite) sensors widened theapplication of satellite data. One of the many fields that these technologiescan be applied is to validate flood inundation models. For a long time floodextent from flood inundation models were validated using the ground truthsurveys which was not very much reliable (M Sathis et all 2012).