Evaluation of runoff and flood-susceptibility of Qal'e Chay watershed in Iran using American method of soil conservation structure (SCS) and geographical information system (GIS).

摘要

Iran is one of the flood-susceptible countries of the world. Every year floods impose a lot of damages in different parts of the country and the world, leading to casualties as well. Floods caused by river overflow are an important phenomenon in our country, nevertheless ignored because of the rare frequency of its occurrence, and soon after its occurrence, it is forgotten. In order to handle this problem, various measures are taken, some of which are controlling the flood itself, like constructing dams and building walls in the river banks; and another section of such measures is management in water catchments, which includes identifying and forecasting the influential factors in the formation and intensification of floods. Considering the fact that we cannot currently modify atmospheric factors and elements in order to prevent the outbreak of such detrimental phenomena, we should thus seek corrective and basic solutions on the ground and specifically in water catchments. Therefore, the regions with a high potential for flooding should be somehow identified. In order to do this, we obviously need to identify flood-susceptible regions in the district, for due to the large extension of water catchments, performing executive and corrective operations in a fundamental manner will not be possible. According to this objective, the Qal'e Chay water catchment has been chosen due to its excessive flood-susceptibility. Various methods have hitherto been used for producing a map of flood-susceptibility, most of which are based upon classic statistical methods or the results from other districts. GIS and remote sensor techniques have provided a better use of these models today. In this study, all effective factors in producing runoff have been taken into account, has been used for river zonation of water catchment flood-susceptibility based on SCS-CN (Soil Conservation Service-Curve Number) method. Using these maps, the sustainable plans can be developed for water resources, and hence provide solutions for dealing with water crises as well as flood control in water catchments. In addition, the effective factors in flood outburst including climatic factors, physiography, geomorphology, geology and district management have been examined.