Rehabilitation of the Lower Murray Irrigation Area to Improve Irrigation Water Use Efficiency and to Reduce Impacts on the Environment

The Lower Murray Reclaimed Irrigation Areas (LMRIA) are irrigated from the Murray River for the purposes of producing pasture primarily for dairying. The poor condition of the existing irrigation infrastructure and the non-metering of river diversions leads to inefficient irrigation practices creating significant drainage volumes, containing high nutrient and bacterial loads, which are returned to the River Murray. Changes in river management, including metering of water use and licensing of discharges requires a major change in irrigation practices for farms to remain financially viable. Rehabilitation options were investigated for Monteith, an area of the LMRIA, to determine the most efficient and viable irrigation system for the area. This included an evaluation of a range of measures to reduce pollutant discharges to the river. The model developed, to predict the changes in river discharges for each option, indicated that a reduction of up to 60% of drainage volumes and 80% of nutrient and bacterial loads could be achieved through the most viable rehabilitation option.