TA528 : Urban River Flood Zoning and Controlling Using GIS
Thesis > Central Library of Shahrood University > Civil & Architectural Engineering > MSc > 2019
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Abstarct: The propose of study is flood zoning and identification of hazard map in Aq’qala county. In this study for extracting time series flood maps on March 2019 in Aq’qala County have been used Sentinel-1 radar satellite data. Sentinel-2 and Landsat-8 optical satellite data are the high resolution and free available data. The NDWI and MNDWI indexes applied after applying preprocessing on optical data. The area of food zones calculated for Aq’qala county and Aq’qala city separately. The maximum of area of flood zones for MNDWI index on 3th April in Aq’qala county and Aq’qala city were obtained 262.453 (km2) and 51.091 (km2) respectively. Furthermore, simulated the flood maps for 10, 50, 100 and 500 year return period using HEC-RAS. The results shown that Gorganrood river would drain out of the river channel if it was not dredged for a period of up to 500 years. In order to the study effect of Gorganrood river channel morphology on flood zones, channel length index, channel width, sinuosity and mean radius of channel were calculated at four sections between Salaq Yelqi village to Dogunchi village. In Salaq Yelqi village to Aq’qala city, the sinuosity index is 3.88, indicating a channel with severe meander, and mean low bed width and low slope between Aq’qala city and Dogunchi village cause floods to return to Aq’qala urban’s area. Furthermore, identified effective criterion and sub-criterion in creating floods of Gorganrood river and Aq’qala city with field surveys and consultations experts of Golestan province and weighted using AHP method and overlaying in GIS software and then flood risk maps were produced. Topographic and morphological criterions with 0.353 and 0.333 weights, respectively had the most impact on flooding in Aq’qala county. Finally, the flood maps obtained comparing with satellite data and archived aerial photography for validation. The Aq’qala county was located in 4.45%, 21.43%, 20.95%, 35.27% and 17.9% zones were very low risk zone, low risk, intermediate risk, high risk and very high risk, respectively. Canalizing and dredging the river channel in the Salaq Yelqi village to Gangirma village, upgrading the bridges in the Yampi village and channeling, dredging and proper alignment in the urban’s area of the Gorganrood river are measures that can help reduce the risk of flooding in Aq’qala city. Flood hazard zoning maps can available to competent authorities to predict the development path of the city and the city of Aq’qala baxsed on flood hazard zoning.
Keywords:
#Aq’qala #Flood Mapping #Gorganrood River #Sentinel data #Morphology #GIS Link
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
Visitor: