Multihazard Rangelands Susceptibility Mapping (Drought, Flood, and Fire) in Siah Bisheh Watershed, Iran

Document Type : Research and Full Length Article

Authors

1 Range Land Management,Natural Resources Faculty, Islamic Azad University of Science and Research Branch

2 University of Tehran

3 Department of range management, Science and Research Branch Islamic Azad University, Tehran, Iran.

4 Department of Rangeland, Natural Resources Faculty, Islamic Azad University Nour Branch. Nour, Iran

Abstract

This study was conducted to prepare a map of multi hazard (drought, fire and flood) to manage the rangelands of the Chalous River basin ( 9312 ha). To investigate the drought the SPI was used using the rainfall data of 21 meteorological stations for period of 30 years.For investigating the fire and flood susceptibility, 8 and 10 effective factors were considered, respectively.The multi criteria decisionmaking method was used to weight the existing layers and prepare the fire risk map. The results of the drought investigation showed that the study area was in a severe to moderate drought range with an SPI of 2.14 to -0.76 and most adjacent areas were also in the normal and near normal drought class.The vegetation types Bromus tomentolus-Festuca ovina and Festuca ovina-Bromus tomentolus were located in areas with higher drought susceptibility. The fire investigation showed that distance from the village (0.249), litter (0.166), rainfall (0.151) are most effective facors among other factors respectively.The fire risk map showed that the northern part of the study area was very highly susceptible to fire.the rangeland of the study area was not affected by flood risk, and only the areas around the river were affected by floods.the results of the drought, fire and flood risk maps of the study area showed that the central and northern parts of the watershed were of high and very high susceptibility in terms of multi-hazards. Based on the results obtained from flood modeling using the frequency ratio method, it was determined that this method had an efficiency of 0.98 based on ROC criteria.To determine the final risk map of the Siah Bisheh sub basin, the drought, fire and flood risk maps were consolidated.According to the final risk map, generally the central and northern parts of the basin showed high and very high susceptibility.

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Articles in Press, Accepted Manuscript
Available Online from 17 April 2022
  • Receive Date: 14 October 2020
  • Revise Date: 16 March 2022
  • Accept Date: 17 April 2022
  • First Publish Date: 17 April 2022