Articles | Volume 4, issue 2
https://doi.org/10.5194/esurf-4-407-2016
https://doi.org/10.5194/esurf-4-407-2016
Research article
 | 
20 May 2016
Research article |  | 20 May 2016

Modeling long-term, large-scale sediment storage using a simple sediment budget approach

Victoria Naipal, Christian Reick, Kristof Van Oost, Thomas Hoffmann, and Julia Pongratz

Abstract. Currently, the anthropogenic perturbation of the biogeochemical cycles remains unquantified due to the poor representation of lateral fluxes of carbon and nutrients in Earth system models (ESMs). This lateral transport of carbon and nutrients between terrestrial ecosystems is strongly affected by accelerated soil erosion rates. However, the quantification of global soil erosion by rainfall and runoff, and the resulting redistribution is missing. This study aims at developing new tools and methods to estimate global soil erosion and redistribution by presenting and evaluating a new large-scale coarse-resolution sediment budget model that is compatible with ESMs. This model can simulate spatial patterns and long-term trends of soil redistribution in floodplains and on hillslopes, resulting from external forces such as climate and land use change. We applied the model to the Rhine catchment using climate and land cover data from the Max Planck Institute Earth System Model (MPI-ESM) for the last millennium (here AD 850–2005). Validation is done using observed Holocene sediment storage data and observed scaling between sediment storage and catchment area. We find that the model reproduces the spatial distribution of floodplain sediment storage and the scaling behavior for floodplains and hillslopes as found in observations. After analyzing the dependence of the scaling behavior on the main parameters of the model, we argue that the scaling is an emergent feature of the model and mainly dependent on the underlying topography. Furthermore, we find that land use change is the main contributor to the change in sediment storage in the Rhine catchment during the last millennium. Land use change also explains most of the temporal variability in sediment storage in floodplains and on hillslopes.

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Short summary
We present a new large-scale coarse-resolution sediment budget model that is compatible with Earth system models and simulates sediment dynamics in floodplains and on hillslopes. We applied this model on the Rhine catchment for the last millennium, and found that the model reproduces the spatial distribution of sediment storage and the scaling relationships as found in observations. We also identified that land use change explains most of the temporal variability in sediment storage.