Whose water is it?
Who owns the water in the Murray-Darling Basin Commission storages on the River Murray and lower Darling and how does it get divided up? The two upriver States - Victoria and New South Wales - share equally the water flowing into the Hume, Dartmouth and Menindee Lakes storages but must provide a defined allocation to South Australia, of which a substantial proportion is reserved for environmental flows in the lower Murray. In times of severe drought each of the three States gets a third of what is available. The two upriver States also control the water in their tributaries to the Murray, although the level of extraction is now constrained by the Cap on further increases in water diversions. In addition, there are a number other factors that must be considered. These include the requirement to supply South Australia with minimum monthly flows (which may be reduced in times of drought) and to carry over water for future years in order to reduce the impact of prolonged dry periods.
Working within these principles, each State makes it own decisions as to how its share of the water will be used, most critically - how much water should be distributed and how much should be held in reserve for the future? At any given time it is normal for the three States to have varying amounts held in reserve in the storages. New South Wales generally holds lower volumes in reserve than Victoria because it has predominantly annual crops. Victoria has more permanent pasture and horticulture which require higher security of supply. It should also be noted that water use planning by the States extends well beyond the current season to take account of the possibility of prolonged drought in future years. An additional dimension to the system is that it is sometimes possible to supply South Australia's requirement from water stored in the Menindee Lakes and Lake Victoria. The water in the Menindee Lakes comes from the Darling River system, fed by the summer rains of southern Queensland and central northern New South Wales. When this occurs, as was the case the late 1990's and 2000, it reduces the demand on the Dartmouth and Hume storages which are then in a better position to supply irrigators on both sides of the Murray upstream of the junction with the Darling at Wentworth. The water is shared between New South Wales, Victoria and South Australia according to an agreement first developed in 1914. Details of the agreement have been changed since then but the principles upon which it is based remain the same. To administer the Murray-Darling Basin Agreement the State governments in the Basin (including Queensland and the ACT) and the Commonwealth established the Murray-Darling Basin Commission. The Commission implements the terms of the Murray-Darling Basin Agreement according to rules defined by the partner governments. The water sharing arrangements are administered by the Commission's water business unit, River Murray Water, which delivers bulk water to the three States as required and manages the system's major assets such as the storages. See also: |
NATURAL RESOURCE MANAGEMENT
