ecosystem at the mouth of the Murray is of particular scientific and cultural
significance. During the drought, natural flows of water to the Coorong and the
lakes immediately upstream stopped, raising grave concerns about the continued
viability of these water bodies and the associated ecosystems (CSIRO 2008).
Irrigation and policy
Among the world’s major river systems the Murray-Darling has both the lowest
average rainfall and the greatest proportional variability. In order to manage the
uncertainty associated with water availability, the rivers of the Basin have been
regulated by large dams in an attempt to ‘drought-proof supplies (Khan 2008).
Close to 50 percent of average annual surface water flows are diverted for
consumptive use, most of which is used by agriculture.
The history of irrigated agriculture in the Murray-Darling Basin has been
dominated by government or government-sponsored development initiatives.
Unlike the situation in many countries with riparian or appropriation rights,
state governments claimed ownership of all water flowing in streams. Water use,
either through direct extraction from streams, or from irrigation systems was
allowed under licenses that were fixed in duration and tied to specific pieces of
land (Quiggin 2001).
Until the 1980s, Australian irrigation policy was in the expansion phase
characteristic of water systems where resource constraints are not immediately
binding (Randall 1981). Policy was guided by a developmentalist, ‘nation-
building’ framework, in which public investment was directed towards objectives
of growth in production and regional population, with no expectation of a return
on publicly invested capital (Davidson 1969).
By the late 1980s the capacity of the Basin to support additional diversions was
almost exhausted. In 1992, the Murray-Darling Basin Agreement was signed,
replacing the 1915 River Murray Waters Agreement. The central idea was to
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