A catchment scale evaluation of the SIBERIA and CAESAR landscape evolution models

Abstract

Landscape evolution models provide a way to determine erosion rates and landscape stability over times scales from tens to thousands of years. The SIBERIA and CAESAR landscape evolution models both have the capability to simulate catchment-wide erosion and deposition over these time scales. They are both cellular, operate over a digital elevation model of the landscape, and represent fl uvial and slope processes. However, they were initially developed to solve research questions at different time and space scales and subsequently the perspective, detail and process representation vary considerably between the models. Notably, CAESAR simulates individual events with a greater emphasis on fl uvial processes whereas SIBERIA averages erosion rates across annual time scales. This paper describes how both models are applied to Tin Camp Creek, Northern Territory, Australia, where soil erosion rates have been closely monitored over the last 10 years. Results simulating 10 000 years of erosion are similar, yet also pick up subtle differences that indicate the relative strengths and weaknesses of the two models. The results from both the SIBERIA and CAESAR models compare well with independent fi eld data determined for the site over different time scales. Representative hillslope cross-sections are very similar between the models. Geomorphologically there was little difference between the modelled catchments after 1000 years but signifi cant differences were revealed at longer simulation times. Importantly, both models show that they are sensitive to input parameters and that hydrology and erosion parameter derivation has long-term implications for sediment transport prediction. Therefore selection of input parameters is critical. This study also provides a good example of how different models may be better suited to different applications or research questions.

Modeling the sensitivity of sediment and water runoff dynamics to Holocene climate and land use changes at the catchment scale

“…It was previously shown that simulating long term soil erosion using models based on average rates fails to predict the contribution of individual events, which may vary largely (e.g. Hancock et al, 2010). Soil erosion increased 64-fold between~4800 BCE and~1990 CE, while colluvial sediment deposition increased 362 times, and export to the fluvial system increased with a factor of only 38.…”

“…Models and model applications vary in their spatial and temporal scale, and as such also in the details to which the processes are studied. Hancock et al (2010) show that the Caesar model is better in simulating event based fluctuations. When running them on large (10,000 a) timescales, such event based models result in comparable landscapes as those from models based on average rates, although erosion and deposition rates may differ by an order of magnitude (Hancock et al, 2010).…”

“…Hancock et al (2010) show that the Caesar model is better in simulating event based fluctuations. When running them on large (10,000 a) timescales, such event based models result in comparable landscapes as those from models based on average rates, although erosion and deposition rates may differ by an order of magnitude (Hancock et al, 2010). Peeters et al (2008) show that an approach based on average erosion rates produces realistic results over a Holocene timescale.…”

Climate, tectonics or morphology: what signals can we see in drainage basin sediment yields?

“…CAESAR was initially developed to examine the relative roles of climate and land cover change on geomorphology and sediment yield and has been applied to a range of real drainage basins with outputs successfully compared to independent field data. These examples include patterns of sedimentation in Alpine environment (Welsh et al, 2009) sediment yields and longer term lowering rates from Northern Australia (Hancock et al, 2010), comparisons to field plot experiments (Coulthard et al, 2012a), predicting patterns of contaminated sediment dispersal (Coulthard and Macklin, 2003) and simulating 9000 yr of drainage basin evolution in the UK (Coulthard and Macklin, 2001).…”

Applications of Long‐Term Erosion and Landscape Evolution Models

“…To place the a range of 0-1 implied by traditional models in context with respect to the evolution of natural slopes: • a value of a = 0 means that rilling cannot occur and that the long profile of the final equilibrium slope is a flat plane (see Fig. In a comparison study of two LEMs, SIBERIA and CAESAR, Hancock et al (2010) showed that slight differences in this aspect of the two models resulted in subtle but noticeable differences in their long-term sediment transport predictions. 18.6).…”