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8528299 
Journal Article 
Assessing the spatial variation of dairy farm total phosphorous losses in the Duck river, NW Tasmania 
Broad, ST; Cotching, WE; , 
2009 
UNIV WESTERN AUSTRALIA 
NEDLANDS 
3471-3477 
WOS:000290045003074 
The Duck is a highly developed 540 km(2) catchment in the northwest corner of Tasmania, with nutrient exports dominated by dairy production (Pinto et al. 2003) undertaken on approximately 19% of the total area. To calculate total phosphorus loads delivered to the Duck estuary, a model was developed using the WaterCAST framework. The daily time step model was created using a ground truthed version of the Australian Bureau of Regional Sciences (2003) land use map, a 5km climate grid (Jeffery et al 2001) and the AWBM rainfall runoff model (Nash Sutcliffe Criterion (NS)=0.88 and R(2)=0.91). The nutrient generation component used the event mean concentration, dry weather concentration method (Chiew et al. 2002) and was parameterised using end of catchment and within catchment nutrient samples taken by the Tasmanian Department of Primary Industries and Water from 1999 to 2001 (Pinto et al. 2003). The resulting modelled outputs were verified using DPIW monthly grab samples collected from 2003 onwards (www.water.dpiw.tas.gov.au) resulting in a NS=0.64 and R(2)=0.66. The process of model parameterisation uncovered large differences in total phosphorous generation rates from dairy pastures throughout the catchment, and to a lesser extent grazing modified pastures (Table 1). These results were backed up with significant differences in the soil test Olsen phosphorus levels. 
Anderssen, RS; Braddock, RD; Newham, LTH; 
Combined IMACS World Congress/Modelling and Simulation Society-of-Australia-and-New-Zealand (MSSANZ)/18th Biennial Conference on Modelling and Simulation 
Cairns, AUSTRALIA