Investigation of material transport and load in tidal rivers

The transport of suspended particulate matter and of heavy metals in tidal rivers is of both ecological and economic relevance. But temporal variabilities and spatial heterogeneities considerably complicate its quantitative treatment by numerical simulation and the acquisition of representative field data for systematic investigations. As a contribution to the potential solution of this problem, a methodology has been developed at the GKSS Research Centre which combines theoretical and experimental techniques in an effective way. A novel measuring system on board a ship allows the fast determination of hydrographie parameters, and water samples are taken in parallel from different depths. Various analytical techniques are applied for quantitative trace-element detection. The experimental data are used as boundary conditions in hydrodynamic and transport model calculations. In the paper, the experimental equipment, techniques, and numerical models are described. Some results of first promising investigations are presented: Lateral distribution of water transport, tidal variation of vertical turbidity profiles, settling velocities, cumulative transp.ort of suspended matter and heavy metals, dissolved and particulate heavy-metal contents and, in part, their tidal variations.