Mapping the flood-prone areas for developing a flood risk management system in the northeast of Iran

Flood hazard and disaster in Iran is one of the most frequent and damaging types of natural disaster. The Gorganroud watershed in the Golestan province recently has incurred severe damages resulted from flood events. Thus, this work was aimed to assess and map the flood susceptibility areas in the Gorganroud watershed to propose a comprehensive layout for flood monitoring and alarming stations. The Analytic Hierarchy Process (AHP) integrated with Weighted Linear Combination (WLC) approach within the GIS environment was employed to extract flood hazard zones. Results revealed that the cities Maraveh Tape, Bandar Gaz, Gorgan, Galikesh, Kordkooy, Minoodasht, Azadshahr, Kalale, Ramian, Gonbadkavoos, Aghala, Bandar Torkaman, and Gomishan with the ranks of 1 to 10, respectively populated the highest proportion of the "High" hazard class. Additionally, two percentages of the cities Aliabad, Azadshahr, Galikesh, and Gorgan were exposed to the hazard class of "Very High". According to results, about 32% of the villages and 26% of their population in the study area are exposed to the high and very high flood hazard zones. Furthermore, around 50% of the populations within high and very high hazard zones are 65 yr who are vulnerable to natural hazards. Based on the results of the flood hazard zoning, a layout of the monitoring plan for the flood warning system in the Gorganroud basin was proposed. This plan comprised 74 repeater stations and 215 alarming stations and fourteen control and monitoring centers were considered to collect and display data from all stations, as well.