http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12319 There are a number of landscape evolution models now developed to the stage where they can be routinely used for both geomorphic evaluations and quantification of soil erosion rates and processes when subject to the action of rainfall and runoff. These models have considerable advantages over traditional modelling approaches as they remove the need to manually determine slope length and angle and because they can also determine both erosion and deposition. A further advantage of digital elevation based models is that they dynamically adjust the landscape in response to erosion and deposition, thus producing a better representation of slope length and angle over the duration of the simulation. A recent advance is that these models now have the ability to employ spatially variable hydrological and erosion parameters, the spatial distribution of soil particle size at user defined soil depths as well as several different flow direction algorithms. While these options are available in these models, minimal evaluation of these hydrological and geomorphological functions has taken place to assess whether they are correct. This study evaluates the well known SIBERIA and CAESAR models for their ability to predict landscape form and erosion for a grassland catchment in South-East Australia under similar rainfall conditions. The results demonstrate that both models predict similar hillslope form as well as erosion rates over a 1000-year modelled period. They also predict erosion rates within the range of independently determined field measured data using environmental tracers at decadal time scales for the site and region demonstrating the models are reliable in the setting examined here. 2012-12-19T02:05:17.086Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:10556 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 fluvial 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 fluvial 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 field 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 significant 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. 2012-04-16T06:00:02.200Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8149 In recent years there has been a focus on the impact of changing climate on rainfall and storm patterns both globally and in Australia with research directed to examine how the global hydrological cycle will respond to climate change. This study investigates the effect of different rainfall patterns on erosion and sediment transport rates in a small study catchment in the Northern Territory, Australia. There have been several studies of the effect of climate change on rainfall patterns in the study area with projections indicating an increase in storm activity. Therefore it is important that the impact of this variability be assessed in terms of catchment hydrology, geomorphology and sediment transport and erosion rates. In this study a numerical model of erosion and deposition (CAESAR) is used to assess several different rainfall scenarios over a 1000 year modelled period. The results show that at the end of a 1000 year modelled period the simulated catchments are not geomorphologically or hydrologically different from one another. The model results reveal that increased rainfall amount and intensity increases sediment transport rates but predicted annual sediment output from the models was variable and non-linear but within the range of measured field data for the catchment and region. The study provides a sensitivity analysis of both initial soil particle size distribution used in the erosion model and rainfall on long-term erosion rates and catchment sediment transport. 2011-07-07T01:50:18.142Z ]]>