Flash flood damage mapping in arid environment using satellite remote sensing — A case study of pali region

In the Bali and Pali tehsils of Pali district of western Rajasthan, which were affected by floods during the period August 6–10, 1990, using IRS-1A LISS-1 data of post-flood and ground truth, seven flood damage categories viz. (1) loss of bund and slight sheet erosion (2) loss of bunds, severe sheet and rill erosion and few gullies (3) deep gullies (4) water inundated area (5) moderate scouring and sand casting (6) severe scouring and sand casting and (7) river widening and bank cutting have been mapped. Out of seven, four categories could be mapped visually on the raw FCC (post-flood) and remaining three categories could be separated out from the digitally generated FCC. The PC₂ was found to contain maximum information on soil erosion/deposition and inundated areas. Density-slicing of band-ratioed output gave maximum information on newly formed channels, water bodies and flow direction. The damage caused to be human beings, animals, agricultural lands, engineering structure by different type of flood hazards under various geomorphic flood zone and comparison between pre-flood and post-flood product has been highlighted.