MEASUREMENT AND MODELING OF SUSPENDED SEDIMENT DYNAMICS IN WATERCOURSES

Abstract

The problem of sedimentation in surface waters has considerable implications for environmental protection, but also for the use of hydropower on the watercourse and for long-term planning of flood risk management and water management. For an efficient management of suspended sediments, it is necessary to carry out appropriate measurements in order to maintain the quantity and dynamics of sediment movement as a function of changing hydraulic conditions. The data collected on site are the input for the development of a suitable model that can be used to establish a long-term plan for sediment management and to calibrate the numerical models. The paper presents an analysis of suspended sediment measurements in a Slovenian river. A correlation between concentration and discharge was investigated, especially during flood event. The suspended sediment dynamics depends on energy conditions, i.e. material is transported during high discharge events and deposited during low flow. The model of the suspended sediment concentration is a function of the water runoff and the amount of sediment deposition. Different models should be used at low discharge and at high discharge to correctly predict the amount of transported sediment concentrations. When modelling flood events, an additional sediment supply term should be added to the rating curve.