A salt and water balance model was developed to represent stream flow and salinitygeneration processes following land use changes. At first a fundamental building-block modelwas developed based on the ‘downward approach’. The building-block model was tested andvalidated with data from six experimental sub-catchments within the Collie River basin in WesternAustralia. The approach requires specification of five physically meaningful key parameters, mostof which can be obtained a priori or easily calibrated.Streamflow and salinity from the Collie River catchment, with an area of 2,545 km2, has increasedsignificantly due to clearing of 26% of the area during 1940-70s. For this study the catchmentwas divided into 91 sub-catchments and the building-block model was applied to each of the subcatchments.Most of the known catchment attributes such as stream length, average slope, soiltype, profile thickness and salt storage were incorporated into the model. Parameter values obtainedfrom experimental sub-catchments were appropriate for representing the daily streamflowgeneration processes of the whole catchment. However, the prediction of stream salinity and saltloads was improved by running the model a number of times and taking the final values of thetransient stream zone stores as an initial condition. The modelled daily stream flow, salinity andsalt load hydrographs matched very well for all gauged sub-catchments.
|Journal||Australian Journal of Water Resources|
|Publication status||Published - 2003|