Assessing the Impacts of Climate, Groundwater and Land Use on Regional Geomorphology

Abstract:

The CLiDE (CAESAR-Lisflood-DESC) platform integrates a variety of modelling components, in order to represent coupled environmental processes and assess their co-evolution over daily to centennial time-scales. A distributed surface-subsurface water partitioning component lies conceptually at the platform centre; providing the key linkages between the atmospheric, sediment transport and vegetation components. Fluvial sediment transport is simulated using the CAESAR model, which has previously been used to investigate a variety of sediment transport, erosional and depositional processes at centennial to millennial scales. Driving CAESAR with a higher resolution, distributed hydrology allows CLiDE to effectively capture geomorphological features that operate at sub-centennial timescales. Non-fluvial sediment transport at the mesoscale is handled by a debris flow component, which drives sediment transport through exchanges of energy and is triggered through modification of local gradient and hydrology. The coupled nature of the platform allows a variety of geomorphological assessments to be undertaken.

We present a variety of regional scale, modelling case studies, which assess the impacts of climate, groundwater and land use on geomorphology. We investigate the non-linear influence of these drivers on the spatial and temporal evolution of river basins and find that antecedent conditions can have a major influence on future erosion events.