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.

Advances in Monitoring and Understanding the Dynamics of Suspended-Sediment Transport in the River Drava, Slovenia: An Analysis More than a Decade-Long

“…Figure 9 displays the correlation between the concentration of suspended sediments and discharge for a specific stretch of the River Drava during a high-water event in October 2018. A counter-clockwise hysteresis loop was observed, indicating that sediment sources were located at the area's far end, contributing to surface runoff, which suggests that sediments reached the stream during the falling limb [38]. However, the hysteresis loop may also have occurred due to material eroded in a catchment that did not reach the stream during the previous flood event and settled on the slope.…”

“…The aim of this case study was to investigate the concentration of suspended sediment in the River Drava during a flood event. The detailed description of the measurement procedure and the results have already been published in [38], but in order to give a comprehensive picture of sediment transport in the Drava, some main conclusions are summarised below.…”

“…Sci. 2023, 13, x FOR PEER REVIEW 14 of 17 to surface runoff, which suggests that sediments reached the stream during the falling limb [38]. However, the hysteresis loop may also have occurred due to material eroded in a catchment that did not reach the stream during the previous flood event and se led on the slope.…”

“…The relationship between the concentration of suspended sediments (C) and water discharge values (Q) was investigated. Time evolution of the water discharge Q and concentration of suspended sediments C for the high-water event in October 2018 (based on[38]).…”