Document Type : Research Paper
Authors
1 Assistant Professor, Soil Conservation and Watershed Management Research Department, Kurdistan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Sanandaj, Iran
2 Associate Professor, Soil Conservation and Watershed Management Research Department, Fars Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Shiraz, Iran
3 Associate Professor, Soil Conservation and Watershed Management Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran
Abstract
Extended abstract
Introduction
Floods cause significant financial losses and loss of life in Iran every year and have detrimental effects on the sustainable development of watersheds. In terms of frequency, flood rank first among the world's natural disasters, and therefore studies related to flood management are very important. Considering climate change and rainfall patterns in the country, in recent years, it has been observed that in addition to changing the rainfall regime from snow to rain, rainfall intensity has increased and sometimes the total annual rainfall of a watershed is discharged in two or three events, which, considering the saturation of soil moisture in these conditions, causes severe floods. On the other hand, due to the destruction of vegetation in the country's watersheds, conditions are available for surface runoff, and ultimately the probability of flooding in most watersheds of the country has increased. One of the pillars of flood risk management is paying attention to vulnerability, which includes several factors. The purpose of this research is to develop a scientific framework for assessing the vulnerability to flooding in the Zarrineh Watershed.
Materials and methods
In this research, various components including social, economic, organizational and infrastructural were considered to formulate the framework for assessing the watershed vulnerability to floods. For each of the components related to the above vulnerability, several thematic groups were defined, each of which included different variables. In the social vulnerability component, ‘percentage of illiterate population’, ‘percentage of children's and older population’, ‘the amount of cooperation and consultation’, and ‘population size’ were selected as variables. In terms of the economic vulnerability component, the variables of ‘percentage of mortgage or rent’, ‘the percentage of unemployment’, ‘percentage of population lacking vehicle’, and ‘percentage of supply dependency to the outside area’ were taken into consideration. The variables related to the component of institutional vulnerability were ‘without decision centers’ and ‘the percentage of cooperation with executive offices’. In addition, infrastructural vulnerability was investigated based on the variables of ‘percentage of residential units with low resistance’, ‘the percentage without telephone and mobile lines’, ‘percentage without internet access’, ‘the percentage of dirt roads’, and ‘percentage without health office’. After collecting the information of 18 villages of Zarineh Watershed from the relevant departments, as well as direct interviews with the residents of the watershed, the vulnerability of each village to floods was determined based on social, economic, institutional and infrastructure vulnerability indicators. Then, the total vulnerability index was calculated for each village and after its standardization at the scale of Zarineh Watershed, it was classified into five different groups: very low, low, medium, high and very high. Finally, the vulnerability index map of the entire Zarineh Watershed was produced.
Results and discussion
Based on the results, Chehelcheshmeh, Golchidar and Obatu districts have the highest degree of social vulnerability, while the lowest degree of social vulnerability was assigned to Sara and Boyen districts. In terms of economic situation, Chehelcheshmeh, Obatu and Golchidar districts are the most vulnerable and Miradeh and Boyen districts are the least vulnerable. In terms of organizational vulnerability, Sahib, Imam, Sera, Zolfaghar and Namashir districts had the lowest level of vulnerability, but Chehelcheshmeh and Obatu districts showed the highest vulnerability value. In terms of infrastructural vulnerability, Boyen and Namashir districts had the best situation (lowest value of infrastructure vulnerability index) and Golchidar and Chehelcheshmeh districts showed the most critical situation. Finally, based on the total vulnerability index map, it can be stated that Chehelcheshmeh, Golchidar, and Obatu districts were the most vulnerable, and Boyen, Namashir, and Zolfaghar districts had the lowest total vulnerability index.
Conclusions
Based on the findings of this research, the framework based on social, economic, organizational, and infrastructural conditions has made it possible to prepare a flood vulnerability map of the watershed. The variables considered in the calculation of the total vulnerability index are selected in such a way that they cover different aspects and their information can be collected. The framework compiled in this research is flexible and depending on the diverse conditions of the country's watersheds, it is possible to consider other variables. The vulnerability map of Zarineh Watershed has provided useful information for decision makers and managers in flood management. Improving the condition of different parts of the Zarineh Watershed requires detailed planning of the executive bodies in accordance with their social, economic, organizational, and infrastructural conditions.
Keywords
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