| چکیده انگلیسی مقاله |
Extended Abstract 1-Introduction Flooding is a natural phenomenon that like another natural disaster has inevitable destructive effects. Based on physical geography of our country and the accident full in some areas, in some cases adverse effects of floods have been caused irreparable damages. Based on physical geography of our country, in some cases adverse effects of floods have been caused irreparable damages. Much of the country's human centers is positioned in mountainous areas and has semi-arid and dry weather that often caused sudden flooding rains. This situation makes runoff immediately after a rainfall and cased flood-prone areas. Annual flood damage to agricultural resources and people's financial status is very notable. South Khorasan province because of its Semi-arid and dry climate, has erratic and flooding rains that increase the flooding potentials. Also human activities and ecological imbalance considerably increases the amount of flooding damages. The study of South Khorasan Province from flood zoning and determination of at risk human and economic centers and infrastructure is important and can increase awareness and leads to problem-solving. 2- Methodology According to the purpose this research, the data includes climate, hydrology, topography, land use, areas at risk of flooding such as: aqueducts, wells, springs, economic activity centers and human settlements. Climatic data have been provided from National and South Khorasan province Meteorological Organization database in the period 1975-2010. Hydrological data have been collected from Iran Water Resources Company Database. In addition, data on damages of flood have been collected from the provincial branch of the Ministry of Agriculture and the hazard databases office of Ministry of State. For providing of flood zoning map, Spatial analysis and Geo-statistical and Geographical Information System methods are used. 3– Discussion In South Khorasan province flood damages are increasing over time because the population pressure, human activities on ecosystems and the interruption in the ecological balance. Flood zoning in South Khorasan province is affected by following four groups: The first group includes topographical and morphological characteristics of water basins and land use. The second group includes specific economic and infrastructure that suffered the most damages in the flood event. The third group includes variables such as: annual discharge, maximum discharge, 24-hour rainfall, the probability of the discharge in the different return periods. The fourth group includes variables such as: average temperature, minimum and maximum average temperature and the type of climate. The effective layers in flood are includes: slope, natural drainage networks and climatic conditions. Weighting to the effective layers in flood, is taken within the framework of Fuzzy logic system. Indicators used in this case includes: Dunn Index, FCM and ASW. The amount of ASW index among the groups that affect the risk of flood as follows: Group 1: 79%; Group 2: 79/8%; group 83: 3% and Group 17: 4%. Classification of basins in South Khorasan province in terms of the risk of flooding and its damage, is as follows: 1- Severe risk (Qayen- Mousaviyeh, Khosef, Sarayan), 2- Relatively severethe risk (Ferdws, Darah, Zahan, Tous -e- Sina), 3- Moderate risk (Border basin-Shahrokht, Nehbandan, Shaskouh) and 3- Low risk (Qaleh Zari, Dehsolm- Bandan). 4– Conclusion The results of flood zoning in South Khorasan Province showed that much of its population containing 9 cites and it 153 villages with a total of more than 250000 inhabitants that comprises more than 37 percent of the province's population, are at risk from flooding. In addition, a large number of important and vital centers of the province such as airports, universities, power plants and hospitals are also at risk of flooding. This shows that in the past development activities, site selection, land use, planning has been done without paying attention to scientific and spatial planning principles. |