The investigation of the Sistan River morphology using Rosgen classification

Abstract

The Sistan River, located in southeast of the Sistan Plain in Iran and Afghanistan border, branched off the Hirmand River and after passing distance around 72 km, reaches to Lake Hamoon of the Hirmand. In this study, the morphological classification of Sistan River in the distance between Kahak dam and Hirmand Hamoon Lake (with the length of 72 km) was examined using the Rosgen classification. It should be noted that the classification of rivers was conducted at levels I and II of the Rosgen Classification. In the level I, the shape, pattern and gradient of the river were extracted using only field visits as well as satellite images and maps; and river morphology was determined in eight types of A-G using them. Then in the level I, in addition to the parameters in the level I, the classification was completed using other features such as the entrenchment factor, width to depth ratio, sinuosity factor and the diameter of the size of particles in the riverbed; and the classification of this river was conducted by comprehensive classification system in the next step. Under this method, the pattern of the river is of type C5c and C6c.