Effective and efficient environmental water use

In my last post, I wrote about the way that environmental flows management is transitioning from policy, to implementation, to management. One of the fascinating aspects of the requirement for managing environmental water is that in addition to being effective, water use must also be efficient.

One of my favourite authors on this subject, Dr Avril Horne completed her PhD thesis on this topic. She used economic concepts of marginal benefit of additional water to the environment to figure out how to optimise the selection of flow components provided to a river or wetland. She generated environmental response curves for each flow component, which typically have an ‘S’ shape – very little benefit is gained below a flow threshold, then benefit increases as more water is provided, up to the point where benefit gained starts to level off, even when more water is provided (see the diagram below, loosely adapted from Dr Horne's work). This has two really important lessons for environmental water managers, as well as for politicians.

The 's' shape: relationship of environmental benefits to volume of environmental water 

Firstly (and this will likely not be news to many people reading this), benefits are not delivered in a linear fashion (Lin Crase has also written extensively on this), and won't measurably occur until after the first bend in the 'S' shape. This means that half the water may well have substantially less than half the environmental benefits, depending on where that volume of water gets you on the environmental response curve. For example, when bird populations breed in the Barmah Wetlands in the Murray, they do so in response to water levels. If the water then drops below the required level before breeding is complete, the nests will be abandoned. If environmental watering can’t be maintained until the birds have fledged, the benefit of using that water would be zero. The Victorian Environmental Water Holder has been using water in the past year to maintain required water levels for bird breeding events in Gunbower Forest and Barmah-Millewa Forest.

The understanding that thresholds must be met before any benefit can be realised is one that politicians can struggle with. Watching the way the new Murray-Darling Basin Plan operates will be interesting on many levels, but one of the most interesting things will be to see how this concept feeds into analysis of how effective the plan (and the accompanying water recovery) has been. The water provided under the plan is already less than that recommended to maintain the health of the Murray-Darling Basin.  If the benefits achieved are lower than we thought, we must consider whether we had sufficient water to exceed the lowest benefit thresholds.

Secondly, after the second bend in the 'S' shape, more water is no longer better, in terms of the benefits obtained per volume of water used. More benefit could potentially be obtained by using that water in another catchment, or to provide another flow component. Environmental water managers in Australia have never before had so much water requiring active management. At the Commonwealth level, most of the water entitlements held by the Commonwealth Environmental Water Holder are entitlements in storage, and these entitlements are incredibly flexible – access to interconnected water delivery systems and the water market means that water can be delivered to a wide variety of locations. Each decision to use water is also a decision not to use it somewhere else. As a result, environmental water managers must not only consider effectiveness, but also efficiency.

Transition to efficiency as well as efficacy is not easy, and depends on detailed understanding of the response curves of the environment. In many cases, this science won’t exist yet, and environmental water managers will be learning on the job. But as the industry matures, we should start to see efficiency playing a bigger role in environmental water decision-making.

Welcome to the blog!

Environmental water management is changing. Driven by factors like climate change, drought, flood and increasing awareness of the plight of threatened species that depend on healthy rivers and wetlands, around the world, policy programs to restore environmental flows have proliferated. In some places, we are investing huge sums of money in recovering water for the environment. For example, in the Murray-Darling Basin in Australia, the Commonwealth Government is investing AUD3.1 billion in water purchase, as well as another AUD5.8 billion in efficiency projects, which will also increase water availability. Under the newly released Murray-Darling Basin Plan, this will deliver 2750GL of environmental water (with another 450GL to follow).  Whilst this is the biggest program of its kind in Australia, state governments have also been investing large sums in environmental water recovery. This sort of investment is also taking place in the western states of the USA, where a range of government and not-for-profit environmental water organizations work with irrigators to restore instream flows.

In some ways, we've got more environmental water than we've ever had, since extractions reached their modern levels. Whilst recovery is still important, in many places, the emphasis is switching to the importance of managing the recovered water. Environmental water managers have to show their investors (taxpayers, or donors to private organizations) that they can get 'bang for buck' with their water. In some places, this is as simple as protecting the improved instream flows (not actually all that simple in practice!). In others, it can include making use of the opportunities and increased flexibility offered by active water markets, to move water around geographically, and convert water into money that can be invested in alternative methods to improve the health of aquatic habitat.

With more water, and more active management required, the role of environmental water managers, and the process of environmental water governance, has never been more important. How can environmental water be managed effectively, and efficiently? How can environmental water managers ensure they have sufficient flexibility to manage changing water needs, especially in a climate change future when extreme weather events might be more frequent? How should environmental water managers retain some independence from the politics of the government of the day, yet remain responsible to the public for managing a public resource?

It's never been a more exciting time to be an environmental water manager, or to be researching those who are. This blog will consider all these questions, and more, and will hopefully also include some guest authors who know far more about the activities of their own organizations than I do.