Flood risk analysis and zoning and its relationship with vegetation in Qirokarzin County

Flood is one of the most destructive weather hazards in the world. The frequent occurrence of urban floods has affected public safety and limited the sustainable development of the social economy. The present study was conducted with the aim of preparing a flood intensity zoning map and analyzing its relationship with vegetation in Qirokarzin city in Fars province. For this purpose, after reviewing various sources, by introducing five effective criteria in the occurrence of floods, which were repeated in other researches in this field, the factors of height, slope, and distance from the river, topographic index and height of runoff were selected as effective factors. By using the method of network analysis process (ANP) in Super decision software, weighting and then using the simple weighted sum method, the final map has been obtained. In this regard, vegetation changes have been obtained using Landsat images in 2000 and 2021 and NDVI index. The results showed that the most effective criterion was the topographic index and Qirokarzin city was located in five zones of very low, low, medium, high and very high risk of flooding, among which 1849/6 square kilometer (54.8%) of Qirokarzin city were in the zone with the risk of flooding is very high. also, the analysis of vegetation changes showed that despite the development of agriculture and horticulture and the resulting relative improvement of the average values of the NDVI index, in the upper reaches of the watersheds of this city, the vegetation cover of forest and pasture lands has decreased significantly, and finally the effects of this problem lead to residential areas and agricultural and horticultural lands in 2021 compared to 2000 are located in areas with high flood potential with a higher percentage, this issue can confirm that the protection of land use in the upstream area is in accordance with to what extent can the policy of maintaining the existing cover and developing vegetation covers by using plants that have high soil protection value play a role in mitigating and suppressing the flooding of the downstream lands.