Regional approach leads to better
outcomes than those made on individual dams
Decisions about whether to build,
remove or modify dams involve complex trade-offs that are often accompanied by
social and political conflict. A group of researchers from the natural and social sciences, engineering, arts and humanities, including an environmental economist at the University of Rhode Island, has joined forces to show how, where and when it may be possible to achieve a more efficient balance among stakeholders.
Their research, a collaborative
National Science Foundation project, was published this month in the Proceedings
of the National Academy of Sciences.
“We have lots of dams and aging
infrastructure and a growing demand for river restoration,” said Emi Uchida,
URI professor of natural resource economics. “But there is also a growing need
for renewable energy, including hydropower. When it comes to dam removal or
improvement, there are a lot of complex trade-offs, and navigating those
trade-offs is a huge societal challenge.”
In some parts of the world, there
are proposals to build thousands of massive new dams for hydroelectricity,
flood control and irrigation.
In other regions, such as the United States, there is a growing movement to restore rivers by removing dams that are obsolete, pose safety risks or have large negative impacts on ecosystems.
In both instances, difficult trade-offs and divergent stakeholder preferences can greatly complicate decision-making processes.
In other regions, such as the United States, there is a growing movement to restore rivers by removing dams that are obsolete, pose safety risks or have large negative impacts on ecosystems.
In both instances, difficult trade-offs and divergent stakeholder preferences can greatly complicate decision-making processes.
For example, conservation groups and resource agencies seeking to restore sea-run fish often favor the removal of dams that prevent these species from reaching their spawning grounds.
But other stakeholders may value the diverse services that dams can provide, including water supply, hydroelectricity and reservoir-related recreation.
“In Rhode Island, we just passed a
ballot measure for the green economy, and part of it will be spent on dam
removals,” Uchida said.
“We want to make smart decisions about which to remove, and we found there are smarter ways to make dam decisions to get the biggest bang for the buck with minimal consequences to other ecosystem services that we would have only with intact dams.”
“We want to make smart decisions about which to remove, and we found there are smarter ways to make dam decisions to get the biggest bang for the buck with minimal consequences to other ecosystem services that we would have only with intact dams.”
The research team built a database
of more than 7,500 dams in New England as a model system to search for
decisions that provide efficient outcomes for multiple criteria valued by
stakeholders.
These criteria include habitat availability for migratory fish, hydroelectric power production, water storage, drinking water supply, water quality, recreational use, dam breach risks, waterfront property impacts and decision costs.
These criteria include habitat availability for migratory fish, hydroelectric power production, water storage, drinking water supply, water quality, recreational use, dam breach risks, waterfront property impacts and decision costs.
Using an economic concept known as
the production possibility frontier, combined with a scenario-ranking
technique, the researchers identified potential dam decisions that maximize the
combined ecological and economic benefits, for individual watersheds as well as
the entire New England region.
They found that better decisions are
made when coordination occurs among parties linked to multiple dams in a
region, rather than making separate decisions about individual dams.
“Making decisions at larger scales
would open up opportunities for better outcomes,” said Uchida. “Instead of each
state or each watershed council making decisions on their own, it makes more
sense for the region to collaborate and work beyond its boundaries.
“There will be some distributional
consequences to doing that, however,” she added.
“Not all watersheds will necessarily end up with all of the ecosystem services they desire. Some dams are more cost effective at providing hydropower, whereas others might be more productive at providing fish habitat by removing the dams. So there might be regional disparities as a consequence. But we still would make better decisions by looking at this problem regionally.”
“Not all watersheds will necessarily end up with all of the ecosystem services they desire. Some dams are more cost effective at providing hydropower, whereas others might be more productive at providing fish habitat by removing the dams. So there might be regional disparities as a consequence. But we still would make better decisions by looking at this problem regionally.”
In addition to Uchida, the research
team included URI Professor Art Gold and graduate student Ben Blachly, along
with colleagues from the Rhode Island School of Design, the University of
Maine, the University of Southern Maine, and the University of New Hampshire.
“Our model can help identify
specific decisions that gain the support of a broader stakeholder audience by
providing desirable infrastructure and ecosystem trade-offs,” said Sam Roy, a
postdoctoral fellow at the University of Maine and the lead author of the
study. “This may encourage funders and practitioners to make these decisions a
reality.”
