Author(s): Monika Donner; Edgar Nehlsen
Linked Author(s): Edgar Nehlsen
Keywords: No Keywords
Abstract: Morphodynamic processes in estuaries and subordinated tidal marsh-watercourses result from natural processes and anthropogenic changes in developed coastal zones. As a consequence of human activity, the complex natural system of tidal tributaries has been modified to enhance navigation, farming and settlement through flood defense structures, river regulation, land reclamation, and water management, however neglecting the ecosystem functions of estuaries. This paper combines significant processes in tidal marshwatercourses based on a research study, which were integrated into a specified long-term approach with special requirements according to anthropogenic stresses like barrier management and stagnant water. This long-term approach includes synthetic long-term boundary conditions for inland runoff, tides and anthropogenic stresses. By using a 2d-hydrodynamic and morphodynamic numerical model, which includes a sensitive morphological speed-up factor with respect to cohesive sediment properties, the ranges of uncertainty for different natural and anthropogenic impacts were considered. The resulting longterm riverbed evolution is compared with the measured morphological developments. The unsteady behavior of hydrodynamics and sediment retention are the key indicators for changes in the morphology. Therefore hydro-and morphodynamic indicators, like changes in flood dominance, net sediment flux and the shift of turbidity maximum are taken into account. These indicators represent changes in dynamic behavior due to different anthropogenic stresses on mesoand macro-scale and also provided an instrument for further planning measures.
Year: 2012