Numerical Simulation Of Pore Fluid Flow And Fine Sediment Infiltration Into The Riverbed

The riverbed embodies an important ecotone for many organisms. It is also an interface between groundwater and surface water, two systems that feature numerous distinctions. The riverbed therefore exhibits many physical and biochemical gradients e.g. flow velocity, temperature, oxygen or nutrient concentration. If the riverbed however becomes clogged through input and deposition of fine sediments, its porosity and permeability decrease leads to reduced interconnectivity between both neighboring systems and eventually reduction of the suitability of the riverbed as a habitat for organisms. Reasons for fine sediment infiltration are high inputs of fine sediments from surface runoff or rainwater retention basins and continuous unnatural low flow velocities typically found in regulated rivers. The objective of our current research is to develop a model for the determination of the factors controlling fine sediment infiltration into the riverbed and their quantitative impact on fine sediment infiltration rates, reduction of riverbed porosity, and permeability. To do so, we use several numerical modeling techniques including the popular lattice Boltzmann method.