Hydro-morphodynamic responses of rivers to the construction of hydropower dams: a case study – the Kor River, Iran

Abstract

Rivers are one of the main components of the ecosystem that has changed because of more pressing human activities, such as the building of small and large dams along rivers. The impact of dams on fluvial hydro-morphology in arid and semi-arid regions, such as the Middle East, has received little attention, even if such fluvial corridors represent major sources of livelihood for the local population. In this study, the influence of the Mollasadra Dam, on the hydro-morphological conditions of the Iranian Kor River is numerically investigated using iRIC MFlow_02, by considering different flooding conditions. Simulating different scenarios with and without the dam, and looking at key parameters like flow rate and velocity, sediment transport rate, and bed topography, it is evident that the dam significantly reduces the water discharge and the relative flow velocities, while it has a relatively reduced impact of the bed morphology and sediment transport. This can be ascribed to the fact that the Kor River is a capacity-limited watercourse, characterized by rather coarse material and reduced sediment transport.