Gorphological Analysis of the Mereg Mahidasht River

First, to extract the morphological variables of the channel, such as the Entrenchment Ratio (ER) index, Width/Depth ratio (W/D), curvature coefficient, channel slope, in the software environment. HEC-RAS (version 5.0.7) was extracted and the bed materials obtained from field investigations were collected. And according to the difference of the slope of the river of Mereg River was divided into four reaches and the curvature coefficient and radius of curvature were calculated in the GIS environment (version 10.5) for each section. 44 cross sections were used to calculate the river in level II Rasgen. The results of this study show that Mereg River is in the first reach in the F6 class. in the second and third reaches of the river in the C6 class, and in the fourth reach of the river in the B6 class. The characteristics of cross sections in category F6 are high bed slope, low subsidence index and less developed flood plain, and the potential of side erosion is very high. In the cross sections of category C6, the amount of slope has decreased, in addition, the Entrenchment Ratio (ER) index has increased and the floodplain has expanded, and the controlling effect of vegetation on the stability of the range is very high. cross sections in category B6, the slope is lower than other intervals, the Entrenchment Ratio (ER) index is average and finally the erosion potential of the side is low.