Flood zoning and its impact on land use in the surrounding area using unmanned aerial vehicles (UAV) images and GIS

Identification of flood zones is a basic step in flood risk management, and flood risk zoning provides a quantitative measure of flood risk, thereby enabling appropriate alerts to be provided in times of flood risk and facilitating rescue operations. The purpose of this study was to determine flood zoning using unmanned aerial vehicles (UAV) images and its impact on land use in the Lighvan river area, under the Ajai Chai Basin, southeast of Tabriz in East Azarbaijan province. The digital elevation model (DEM) with 70 cm accuracy was used for flood zoning. After converting the DEM to TIN for pre-processing, data were entered into HEC-GeoRAS software. And with TIN, three-dimensional UAV images were obtained and the height of profiles specified and hydraulic depth of the river extracted. After the pre-processing, the results entered in HEC-RAS software, so after the completion of flow specification and hydraulic data and entering capacity of flood discharges in return periods of 2, 5, 10, 25, 50, 100 and 200 years, flow model and water surface profile with return period obtained. Then the flood zones were combined with the land use map. The results showed that as the increase of return period the capacity increases too; flood zones increase, So that during the return period of 2, 5, 10, 25, 50,100 and 200 years 6.24, 6.31, 6.75, 7.80, 9.69, 10.36 and 11.44  hectares, respectively, were covered by flood cover and It was also found that floods, gardens, barren lands, and residential areas were more affected by floods, respectively.