عنوان مقاله [English]
Destructive Floods which is weather and climatic phenomenon, allocated 35 percent of the natural disasters and annual losses resulted from it in the world is amounting to billions of dollars. Most of the floods, caused by heavy rains, snow and ice melting’s or by rivers flooding. Kalghan basin is one of the Ghezel uzan river reaches and Granghu River is the main drain of it. Kalghan River’s origin is Sahand Mountain with 3707 meters height in the Eastern Azerbaijan. Area of the River Basin in the dam is 202.8 square kilometers with 30.4 kilometer length. In this investigation has been trying to study climatic and rainfall-runoff data with HEC-RAS software to zoon and analyze flood area for 5, 10, 50 and 100 years return period. In the climatic study of the region, Pierson type 3 distributions is used and for HEC-RAS model, Manning's coefficient, contraction and flood return period has been used. Finally, in order to map the flood area geographical information system GIS package was used. The results indicate changes of flood area from 36.2 to 115.5 meters. For example, flood zoning in Kalghan and Jeghir villages differs from 19 to 40 meters. In Beig bulaghy Village, biggest flood zoon reaches to 80 meters, in Cheraghchy village flood zoon reaches to 72 meters in the village and the village of Conduct Chraghchy 80villagesAt the end for maps, Geographical information system is used. The results show that, in case of the lack of necessary operations, flood may cause a great risk for agriculture and resident parts of this river. According to manipulated river bed and placement of rural and agricultural lands in most parts of the river if necessary temperaments don’t take place in this area, flood risk may be possible in the villages around this river.