Integrated catchment assessment of riverine landscape dynamics

Abstract.

The traditional approach to study riverine environments focuses on the river reach scale, with streamflow as a steady state driving force. Here, the accent is on the dynamic nature of streamflow. Impacts of the hydrological regime, of floods and streamflow variability, on riverine landscapes are reviewed. To evaluate such impacts, it is necessary to focus on the entire catchment in an integrated fashion, so that local changes in river morphology and river habitat can be evaluated in context with upstream catchment processes. A framework for an integrated physically-based catchment modelling system, based on models of hydrology, hydrodynamics, sedimentology and ecology, is presented. The hydrological element addresses runoff response in a catchment on a continuous basis in time and distributed in space, while the hydrodynamic, sedimentological and ecological elements address the interactions and feedbacks between water, sediment and the ecosystems at the scale of the river corridor. The models are arranged in a nested fashion, with long-term quantification of catchment and river system dynamics as the main objective. A long-term vision of catchment processes is important for the evaluation of potential anthropogenic influences and climate change effects, as well as for the evaluation of river conservation projects.