Deposition of fine particles varying with their cohesiveness

摘要

Rivers carry enormous amounts of fine particles in suspension compared to the bed load. These particles tend to deposit in regions of low turbulence such as reservoirs, polders or on floodplains. The influence of their respective cohesiveness on the depositional behavior is investigated in a research project. The laboratory study aims to quantify the effect of the cohesive properties of the sediment particles on the deposition process. The cohesiveness is varied by using sediments of different mineralogical composition and by varying the pHvalue of the ambient water. The experiments are realized in an annular flume with a free water surface, where the flow is driven by the rotation of the inner flume boundary. Two artificial muds of silica and alumina particles and a natural mud taken from a reservoir in the black forest are studied. The results show that the steady state concentrations and the deposition rates differ significantly between the diverse configurations.