Modelling sediment fluxes at large spatial and temporal scales

Abstract

A conceptual approach to the representation of long-term regional sediment fluxes is presented. Existing models that directly or indirectly address this objective are reviewed, and various issues associated with large scale modelling of sediment fluxes are identified. The approach offered here is designed to operate at large temporal and spatial scales. It is hierarchical, and provides a framework for integrating the results of various other approaches. The approach is based on the thesis that it is the development of landscape configuration that should be modelled on larger scales, and therefore an aggregated modelling approach for landform structure and sediment redistribution is required. Emphasis is placed on (a) frequency/magnitude spectra as a means of integrating sediment generating processes of different nature, (b) temporal aggregation for parameterisation of driving forces, and (c) routing of sediment through a topological network of morphologically defined landscape units. A series of issues requiring further research are identified, including (1) definition of geomorphic storage units, (2) establishment of effective driving and controlling factors within aggregated phases of landform development, (3) establishment of frequency/magnitude spectra for sediment generating and distributing processes, and (4) form/process/form coupling.