Adaptive management of environmental flows: lessons for the Murray-Darling Basin from three large North American Rivers

Throughout the Murray-Darling Basin it is recognised that rivers are being degraded by changes to flow caused by development of water resources. Proposals to reverse this degradation include the provision of environmental flows, that is, water specifically managed to meet environmental needs. So far, implementation of environmental flows has proved difficult because of competition for water and uncertainties in environmental water requirements. Economic losses from allocating water to the environment are easy to quantify but the benefits can only be vaguely specified, which makes changes difficult to justify.A possible way forward is to use an adaptive management approach to the implementation of environmental flows. The promise of adaptive management is that it facilitates public policy in the face of uncertainty through a structured dialogue between scientists and managers and allows meaningful participation of stakeholders. Adaptive management has been used to address natural resources management issues in large river systems in the United States and three case studies are considered here: the Columbia, Colorado and Mississippi River projects. The case studies show that adaptive management can promote rapid learning and address complex environmental management issues but the process can be also be derailed. Barriers to adaptive management include: jurisdictional and institutional complexity, lack of credible science, and difficulties with developing system models. Adaptive management is more likely to be successful where there are few, well defined points of intervention, early successes for experimental management, shared goals and strong political support. Where experimental policies are seen as too risky or costly, the promise of adaptive management has not been realised. There is the potential to use adaptive management to address implementation of environmental flows in the Murray-Darling Basin but it will be necessary to select a project wisely.