Sensitivity analysis for assessing the behaviour of a landscape-based sediment source and transport model

Widespread degradation of aquatic habitat and water quality has occurred since European settlement in Australia. Repairing this degradation is expensive and hence on-ground management needs to be carefully focussed. The Sediment River Network model, SedNet, used to estimate (spatially) the sources and transport of sediment at catchment scales provides a potentially useful tool to assist land managers in focusing this work. The complete model, while broadly applied has not been systematically tested to assess its sensitivity to its various model components. This paper describes sensitivity assessment to improve understanding of the model, with the aim of prioritising data acquisition and improving the structure and parameterisation of the model where necessary. It was found that the SedNet model was most sensitive to perturbations in its hydrologic parameters across a variety of scales and sites. Because of this it is important that ongoing model development activities focus on how to effectively represent hydrologic processes in the model.