The concept of environmental flows can trace its roots to an assertion that began spreading just a few decades ago, which was both shockingly simple — and audacious.
Shockingly simple because its basic premise was that, to function, rivers need water in them. And audacious because it questioned the prevailing notion that, to function, societies could do whatever they wanted to do to the world’s rivers, including damming, diverting and drying them up. And consequences be, well, dammed.
The goal that initially emerged was to secure the ‘minimum flow’ for a river and the methods employed to set that flow level were themselves quite minimalist, such as designating a certain percentage of average flow as the necessary minimum.
But scientists soon began looking far beyond the minimum.
Researchers were now unleashed on a whole new field of inquiry: for a river to be healthy and provide water for people and nature, and not just minimally wet, how much water did it need? How did that need vary over the course of a year?
In other words, they were asking how does the flow regime of a river — the pattern of rising and falling water levels — influence river ecosystems and the production of things that people value?
Turns out, the answer was “a whole lot.” A river’s ability to support fish reproduction, or floodplain forests, or riverside agriculture, depended on far more than maintaining a minimum flow.
Many of these important resources required high water at certain times of the year, low water at others and with these flow levels occurring in specific sequences or during a specific time of year.
To effectively address this ecological complexity, the number and complexity of assessment methods exploded and the term ‘minimum flows’ gave way to ‘environmental flows’.
The importance of environmental flows, and the need for this evolving science to inform river management, was recognized in the 2007 Brisbane Declaration, which called for widespread assessment of environmental flow needs and implementation of those flows.
Since then, both scientific research and assessment of flow needs have exploded out of the gate. Implementation, however, was left largely still in the starting blocks.
Constraints on implementing environmental flows have included uncertainty over methods, cost and complexity, failure to secure stakeholder or political support, resistance to change from water managers — along with the simple fact that, in many places, water flows are intensely contested as a scarce resource.
Also, the lag in implementation is relative compared to the Declaration’s goal of global uptake and to the progress of assessment. There have indeed been many places where people have solved the implementation challenge.
Ten years after the Brisbane Declaration, WWF has released a report, Listen to the River, which reviews these examples and distills lessons from them.
For example, in the United States, The Nature Conservancy and the U.S. Army Corps of Engineers launched a collaborative programme — the Sustainable Rivers Project (SRP) — for assessing and implementing environmental flows.
The Corps is one of the largest water-management agencies in the world and operates more large dams than anyone else in the US.
Some of the factors that have facilitated environmental flow implementation through the SRP are common to other implementation success stories and are highlighted in Listen to the River:
1. Engage with water managers throughout the process.
In the SRP, scientists didn’t develop flow recommendations and then hand them over to water managers to implement.
Instead, managers and engineers were engaged throughout the process, allowing them to better understand the context for the recommendations — and to feel a sense of ownership in the process and its outcomes.
While not all recommendations could be implemented, this engagement facilitated constructive dialogue and problem solving between scientists and engineers, leading to early implementation of some environmental flows.
2. Include a broad range of stakeholders to cast a wide net for knowledge and support.
SRP processes featured several large-scale workshops with representatives from all levels of government, the private sector and academia and with expertise across the spectrum of science and management.
This breadth of skills and knowledge informed the scientific process of developing environmental flow recommendations and the diversity of institutions increased the social and political support to implement those flows.
3. Keep the science only as complex as needed for decisions to be made and targeted at resolving critical uncertainties.
The rigour and complexity of the science required to support experimental flow releases or new operating plans varies widely across SRP sites.
For example, managers at the Green River in Kentucky formally adopted a new reservoir operating plan that released flows to improve spawning for fish and endangered freshwater mussels, which were based on relatively simple analysis to confirm the flows were consistent with their flood-management responsibilities.
Meanwhile, on the Roanoke River in North Carolina, many years of rigorous modeling of operations and flows, and monitoring results in the field, were required before revised flows could be formalized as a new operating plan.
4. Implement some flow changes as early as possible to aid the learning process and to galvanize support and momentum.
A hallmark of the SRP was that participants strived to begin releasing at least a portion of the environmental flow recommendation at soon as possible.
These experimental flow releases allowed scientists to begin learning based on actual conditions and helped them refine their recommendations. For example, on the Savannah River, managers released an environmental flow intended, in part, to trigger sturgeon to move upstream to spawn.
Several sturgeons were radio tagged but during the release they didn’t move upstream. In fact, they moved in the opposite direction.
It turned out that the water in the flow release was too cold for the sturgeon, allowing the scientists to refine the recommendation to include a temperature component.
In addition to learning opportunities, the early release of environmental flows can attract media attention, increase political support and bust through the myth that environmental flows are wrapped up in complicated processes that are ‘all talk and no action’.
Environmental flows have some parallels with medicine, including relying on scientific methods to diagnose problems and prescribe interventions to maintain or restore the health of the patient.
But the lessons from the SRP, which are summarized in Listen to the River, suggest that environmental flow implementation is more like public health.
Public health has scientific interventions at its core, but its practitioners recognize that, for those interventions to come into play, they need to solve a set of institutional and behavioral challenges, and that social processes of interaction, problem solving and collaborative buy-in can be just as important as the underlying science.
And that’s the greatest challenge for environmental flow practitioners — to turn accepted theory into river-changing practice.
This is why WWF compiled a list of global success stories — to prove that environmental flows make a difference in the real world and not just on paper by benefiting the communities and ecosystems that rely on rivers.
And why it was released on the 10th anniversary of the Brisbane Declaration at the International Riversymposium in the same Australian city — to show how much progress has been made, share lessons and inspire practitioners to redouble their efforts to implement environmental flows in rivers across the world.
Jeff Opperman is the lead scientist of WWF’s Global Freshwater Practice. jeff.opperman@wwfus.org
Find out more and download the report here
