Parameter estimation and uncertainty analysis for a watershed model
Environmental Modelling & Software
Environmental Modelling & Software
An effective screening design for sensitivity analysis of large models
Environmental Modelling & Software
Uncertainty in the environmental modelling process - A framework and guidance
Environmental Modelling & Software
Identifiability analysis for receiving water body quality modelling
Environmental Modelling & Software
Environmental Modelling & Software
A new approach to water quality modelling and environmental decision support systems
Environmental Modelling & Software
Environmental Modelling & Software
Global Nutrient Export from WaterSheds 2 (NEWS 2): Model development and implementation
Environmental Modelling & Software
Position Paper: A quantitative phosphorus loss assessment tool for agricultural fields
Environmental Modelling & Software
Adaptive modelling for adaptive water quality management in the Great Barrier Reef region, Australia
Environmental Modelling & Software
Evaluation of a static water balance model in cropped and grazed systems of temperate Australia
Environmental Modelling & Software
Estimation of water and salt generation from unregulated upland catchments
Environmental Modelling & Software
Decision support for diffuse pollution management
Environmental Modelling & Software
Environmental Modelling & Software
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A catchment-scale framework was developed to assess the contribution of sediment sources from farm management actions, gully and streambank erosion on the suspended sediment loads delivered to rivers and associated wetlands and floodplains for two catchments (Avon Richardson, 2885 km^2 and Avoca, 4550 km^2) in Victoria, south-eastern Australia. After considering commonly available data sets, outputs from the point-scale model (HowLeaky2008) were coupled to a catchment scale framework (CatchMODS). Spatially constant, linear scaling factors were used to link point-scale water surplus to streamflow and gross soil loss to hillslope erosion. The model was calibrated against discharge and suspended sediment loads estimated at water quality monitoring gauging stations. Following calibration, estimates of annual and monthly streamflow and 10-year average annual sediment loads were in good agreement with observations. Catchment-scale outputs, particularly sediment loads, were sensitive to scaling factors. The high sensitivity coupled with limited data hindered tight identification of sediment scaling parameters, therefore sediment outputs were uncertain, particularly in the Avoca catchment. Propagation of uncertainty in parameter estimation to model estimates was assessed qualitatively. The boundaries of model estimations were assessed by retaining predictions of behavioural parameter sets, defined as parameter sets that resulted in efficiencies of sediment load and specific sediment yield estimations not more than 5% lower than the efficiency of the optimal parameter set. Under current management conditions, mean annual suspended sediment load at the Avon-Richardson catchment outlet was estimated to be 3350 (3300-3700) t y^-^1, of which hillslope erosion contributed 65% (60-80%) and gully erosion 35% (20-40%). In the Avoca catchment, annual suspended sediment load was estimated to be 4000 (3500-5100) t y^-^1, of which hillslope erosion contributed 17% (5-24%), gully erosion 72% (55-93%), and streambank erosion 11% (1-21%). In the Avon-Richardson catchment management scenarios showed that alternative farming systems focussed on retaining vegetation cover throughout the year would yield a 50 per cent reduction of suspended sediment load, estimated at 1700 t y^-^1. In contrast, fencing and revegetation of connected gullies was estimated to yield the largest reduction in suspended sediment load (1770 t y^-^1, 44% of current load) in the Avoca catchment. The framework provides an improved tool to make more informed decisions about how much suspended sediment loads can be reduced in response to farm management actions, gully and streambank protection. Its primary strength lies in the ability to propagate farm management impacts to the catchment scale. Other valuable features for use by natural resource management agencies include a high level of transparency, availability of user-friendly interfaces, and a modular structure that provides flexibility and adaptability to new systems.