High flow management as climate change adaptation for freshwater ecosystems in regulated rivers

Rivers worldwide have been disconnected from their floodplains through anthropogenic modifications, leading to a reduction in ecosystem services and decline in condition. These issues will be exacerbated by climate change. We assessed the effectiveness of relaxing river operating constraints to provide managed high flows to improve freshwater ecosystem outcomes in the Goulburn River basin in Victoria, Australia. We used a simplified, integrated ecohydrological modelling framework to help reduce the decision space of options in multiple river reaches, to highlight key thresholds of ecological responses, and to assess the robustness of options to an uncertain future climate. Constraints relaxation was shown to provide overall ecological benefits in the current climate, and to result in adaptation benefits for freshwater ecosystems in drier future climates. Our approach offers a practical way to assess multiple potential intervention options to improve ecosystem outcomes and be robust to uncertain climate change for complex regulated river systems.