A coupled eco-hydro-geomorphic investigation of basin response to climate change: Examining the role of climate on internal basin dynamics

Abstract

Much attention has been devoted to assessing the relationship between changes in climate and landscape evolution. Given the complexity of dependence of geomorphic processes on hydrological and vegetation properties of the system, it is not surprising that different studies of fluvial response to climate change often appear contradictory, making difficult to generalize about how any given drainage basin will respond to changes in climate and/or land use. In this study, an integrated geomorphic component of the physically-based, spatially distributed hydrological model, tRIBS, the TIN-based Real-time Integrated Basin Simulator, is used to analyze the sensitivity of landscapes to climate change over the millennium time scales. Hillslope and channel erosion processes are parsimoniously coupled with vegetation-hydrology dynamics, making it possible to study how the vegetation influences the hydrological and geomorphological processes. A weather generator is used to simulate different climate scenarios and carry out assessments of future impacts of global climate change using downscaled GCM outputs. The integrated model is applied to two synthetic basins using as evaluation benchmark the erosion/deposition quantities over the basins for the different climate scenarios. Causalities between modeled spatial mean states of soil moisture, vegetation biomass, and basin sediment fluxes with selected climatic variables are sought in an attempt to improve the understanding of the lumped basin behavior to climate change.