Application of remote sensing in flood management with special reference to monsoon Asia: A review

The conventional means to record hydrological parameters of a flood often fail to record an extreme event. Remote sensing technology along with geographic information system (GIS) has become the key tool for flood monitoring in recent years. Development in this field has evolved from optical to radar remote sensing, which has provided all weather capability compared to the optical sensors for the purpose of flood mapping. The central focus in this field revolves around delineation of flood zones and preparation of flood hazard maps for the vulnerable areas. In this exercise flood depth is considered crucial for flood hazard mapping and a digital elevation model (DEM) is considered to be the most effective means to estimate flood depth from remotely sensed or hydrological data. In a flat terrain accuracy of flood estimation depends primarily on the resolution of the DEM. River flooding in the developing countries of monsoon Asia is very acute because of their heavy dependence on agriculture but any flood estimation or hazard mapping attempt in this region is handicapped by poor availability of high resolution DEMs. This paper presents a review of application of remote sensing and GIS in flood management with particular focus on the developing countries of Asia.