Analyzing the hydro-morphological indicators of the Balharoud river with the aim of determining the trend and causes of riverbed change

The Rivers and the Canals are a completely dynamic system and their morphological patterns has been changed continuously over the time, which sometimes lead to erosion and damage to coastal facilities and border displacement. Therefore, its hydrologic behavior should always be considered. Iran has several border rivers with its neighbors that its necessary be studied of wise “the bed change approach. In this research, the Balehradud Border River, which forms 62 km from Iran's border with the Republic of Azerbaijan in Ardebil province, be studied based on the substitution approach by studying the hydromorphic indices of the Sinuosity coefficient, bending radius and central angle for the period 1955 and 2016 respectively using the map of Protocol 1/25000 and satellite imagery of ETM. And the indexes were calculated in AutoCAD and Arc maps software. The results show that the Meandering pattern has become more intense over the period of 61 years and the rate of river bed changes has been very high. As for the Sinuosity coefficient, the number of curves of river increase to 857 in year 2016 than 591 bends in year 1955 which indicates a significant change in river morphology. The values of curvature radius in the whole range confirm the existence of approximately the same arch along the river's path. This indicator for year 1955 shows that upstream have more meandering from downstream and versa this mode for the year 2016. Which can be due to climatic and tectonic changes. Also, a number of factors such as human interactions, climatic conditions, vegetation, loose tissue, are involved in the River bed change. It is important to take protective measures, such as stabilizing the coast and increasing vegetation and preventing the dumping of the river.