Challenges and Opportunities in Environmental Water Management: What's working and what can we do better?

Environmental flow assessments have now been part of environmental water management in Australia for over 20 years. During this time the methodology has developed and been standardised, as articulated through guidance documents like the Victorian FLOWS and EEFA methods (for freshwater and estuarine system, respectively). As we increasingly recognise the challenges associated with climate change, and look to integrate cultural flow knowledge and water for Country, there is a need to reflect on what we have done, what has worked and what we can do better. Three recent Victorian studies provide a demonstration of these considerations: the Glenelg River and Lower Ovens River system environmental flows studies, and Snowy River estuary environmental flows study. They are looking into ways of linking Traditional Owner knowledge into the environmental flows framework by working with Traditional Owner groups to bring a cultural flows lens to the assessment process. There are some concepts such as a "seasonal flows calendar", an example of which was developed for a reach of the Glenelg River, that can work alongside more traditional flow seasons. Cultural considerations overlap with how we deal with climate change and "future proofing" environmental flow recommendations. For example, annual streamflow volume reductions, sea level rise and groundwater recharge reductions are not well addressed by current methods, but are increasingly important. For example, in the Ovens River recharge of groundwater is predicted to see reductions of as much as 50% by 2090, particularly during the critical dry summer months. While in the Glenelg River, the frequency of what we currently define as an "average" flow year is predicted to be 50% less, making it no longer the "average" and highlighting a need to shift categorisations and terminology. For the Snowy River estuary reduced river flows will result in longer and more frequent closure of the estuary mouth. These changes have serious implications for our water dependent ecosystems, and research into setting "climate ready" ecological objectives is bringing in new ideas and opportunities. Can we move away from flows targeting species and think more about functional groups? Can we identify where climate change increases the risk of not meeting objectives? And while not specific to these recent studies, but do we also need to better define the needs of urban environnmental flows. We highlight these challenges and present some of the constraints and opportunities when assessing environmental flows into the future. [ABSTRACT FROM AUTHOR]