Site Selection, Design, and Implementation of a Sediment Sampling Program on the Kasai River, a Major Tributary of the Congo River

Abstract

With recent developments in technologies to study sediment transport in water bodies, such as remote sensing and improvements in erosion prediction models, field-derived sediment concentration measurements are still required to calibrate and validate the results of such studies. The details of the establishment of a high-frequency sediment sampling station on the Kasai River, a major tributary of the Congo River, are described. The sampling station is used to measure suspended sediment concentration and river discharge from a catchment area of ~900,000 km 2 , which represents the largest sediment flux into the Congo River, with important consequences for river navigation and hydropower. Preliminary results indicate average suspended sediment concentrations (SSC) of ~518 mg/L with an average percentage soil organic matter (SOM) content of 1.86%. The SSC concentrations recorded are much higher than previous values reported for the sub-basin, pointing to an urgent need for more detailed studies on the present sediment transport dynamics within it. Nephelometric and back scatter turbidity averages are 281.47 FNU and 539.93 FBU, respectively, while the average water temperature in the cross-section is 28.25 °C. This is one of a very small number of sediment monitoring stations in the CRB and the first to attempt this level of high-frequency sediment sampling, aimed at shedding light on sediment transport in the Kasai tributary.