Unfortunate diversions: a policy discourse analysis on the adjustment of the volume of water returned to the environment in the Murray-Darling Basin, Australia

The Murray–Darling Basin Plan, a major initiative to return water from irrigators to the environment, has been lauded as world-class water reform. The enabling legislation for the Basin Plan, the Water Act, gains its constitutional legitimacy from international treaties such as the Ramsar Convention on Wetlands. This Act mandated that water be returned from consumptive uses to the environment. An allocation of 2,750 GL/yr was set but has been reduced by the 'Sustainable Diversion Limit Adjustment Mechanism' (SDLAM), intended to achieve equivalent environmental benefits with less water. We present a synthesis of changes in decision contexts that have led to water reforms being 'watered down'. We analysed the policy discourse of water reform to assess whether SDLAM projects will achieve outcomes congruent with Australia's international treaty obligations. We found little or no alignment between the purpose of the SDLAM projects and the principles of the treaties and the Water Act. As water scarcity increases under climate change, attempting to conserve wetlands (including rivers) with less water while maintaining or increasing irrigation diversions is likely to prove maladaptive. A major reframing of environmental water policy and management is required to enable meaningful and effective adaptation to climate change.