Using Semi-distributed SWAT to Predict Flow and Salt Load in an Irrigated Catchment

The Barr Creek flow is a major source of salt to the Murray River. Salt mobilisation from irrigated areas in the Murray Darling Basin, Australia is of great concern for its impact on downstream irrigation, urban water supply and ecosystems. The Barr Creek catchment situated in the Murray Darling Basin is characterised mainly by irrigated pasture, deep drains and shallow saline water tables. Groundwater discharge into deep drains dominates salt mobilisation from the catchment. In this study we applied the semi-distributed Soil and Water Assessment Tool (SWAT2005) to simulate flow and salt load in the Barr Creek Catchment. SWAT2005 was calibrated for the period August 1992- July 1993 against monthly flow and evaluated for the period between 1994 and 2004. Results showed that flows were better simulated than salt loads. The prediction was reasonable for periods close to the calibration period. Overall the annual trend in flows was better predicted than for salt load. This result however may be improved by integrating SWAT2005 with a fully distributed ground water model.