Fish Run Through It: The Importance of Maintaining and Reconnecting Free-Flowing Rivers

Fly-fishing the Blackfoot River, Montana. Part of The Nature Conservancy's Great Western Checkerboards Project, Montana. Photo credit: © 2014 Steven Gnam for the Nature Conservancy
Fly-fishing the Blackfoot River, Montana. Part of The Nature Conservancy’s Great Western Checkerboards Project, Montana. Photo credit: © 2014 Steven Gnam for the Nature Conservancy

By Jeff Opperman, Director and Lead Scientist, Great Rivers Program, The Nature Conservancy

Eventually, all things merge into one, and a river runs through it.  – Norman Maclean

This sparse sentence by Norman Maclean comprises some of the most beautiful words written about rivers in the English language. It captures how rivers serve as living symbols of place, of home, and how they connect us to each other and to nature.

As a prose poem about rivers and connectivity, the words are masterful. From a scientific perspective, however, the words come up a bit wanting. A river may run through our home valley, but what happens around the next bend, out of sight downstream? In much of the world, around the next bend is a dam and reservoir and the running river slows to a jog, to a crawl, to lying down and waiting. From our own limited vantage points, a river can still run yet be missing something essential.

A better phrase may be: and fish still run through it. For if the fish are moving through that means your river remains connected to the rest of the landscape, up and down. It captures whether a river is all it once was or, more importantly, all that it could be.

Being all that it could be isn’t quite the same as being all it once was – that’s impossible for many rivers.  Even the good people of Maclean’s Montana, who love their rivers running through their valleys, get their water for drinking and farming from rivers that must spend time lying down in reservoirs; much of their electricity is produced from rivers that must run through turbines nestled in dam walls.

Because nearly all of us benefit from dams, we share responsibility for disconnecting rivers, but fish running through our rivers offers a chance at redemption. Where they still run through, can we keep them running? Where they don’t, can they start running again?

These goals are at the heart of World Fish Migration Day (WFMD), which will take place the weekend of May 21, with hundreds of events around the world showcasing the importance of migratory fish – fish like salmon, sturgeon, tiger fish and giant catfish, fish that feed tens of millions of people and carry with them immense recreational and cultural values as they run up and down rivers. (The Nature Conservancy, WWF and the World Fish Migration Foundation will host a kick-off panel event in Washington DC on May 20, which will be aired after 3 p.m. ET on the WFMD site).

Adult chinook salmon jump up waterfall on their journey home to spawning waters in tributaries along the North Coast of California. © Jeffrey Rich
Adult chinook salmon jump up waterfall on their journey home to spawning waters in tributaries along the North Coast of California. © Jeffrey Rich

In addition to celebrating migratory fish, World Fish Migration Day challenges us to overcome the barriers those fish confront on their migrations, and dams are one of their greatest barriers.

Those who seek to promote fish migration must work to find solutions across the whole life cycle of dams—from the planning of new dams to the removal of old ones.

  • In places just now undergoing development, we need to rethink how dams are planned and sited to protect the most important rivers and migratory fish pathways.
  • In places with existing dams, we need to re-design or re-operate them to restore fish habitat or fish passage.
  • In places where aging dams have outlived their purpose, we need to remove them and reconnect rivers.

Rethink, re-operate, remove. Protect, restore, and reconnect.

In countries undergoing rapid expansion of hydropower dams—such as Mexico, Colombia, and Gabon—conservation organizations, governments, companies and funders are working to implement system-scale approaches that improve how dams are planned and sited. Currently, dams are generally proposed and built one at a time, with little or no understanding of how continued development will ultimately affect river systems. A system-scale approach seeks to compare alternative development scenarios upfront and identify those scenarios that can most effectively balance energy development with the protection of migratory fish pathways.

In places with dams that provide significant economic values (and thus are not candidates for removal), agencies that manage dams can improve operations to help restore river ecosystems. In China, resource agencies and conservation organizations are working with Three Gorges Corporation to design and monitor an environmental flow release program from Three Gorges Dam—the largest hydropower dam in the world—to improve spawning conditions in the downstream Yangtze River for four culturally and commercially important carp species, promoting their annual migration from river channel into floodplain wetland.

On the Apalachicola River in Florida, diverse partners contrived a simple fix to help Alabama shad migrate past big hydropower dams.  Using common materials (“You can buy any of the basic equipment at Home Depot,” said the The Nature Conservancy’s Steve Herrington), the team pumped a narrow cascade of water into the navigation lock below the dam.  Instinctively attracted to the sound of moving water, the shad congregate in the lock and then can simply be lifted over the dam, like thousands of tiny barges.

Aerial view of a old dam just off the tip of Indian Island, between the towns of Old Town and Milford, on Maine's Penobscot River. PHOTO CREDIT: ©Mark Godfrey/TNC
Aerial view of a old dam just off the tip of Indian Island, between the towns of Old Town and Milford, on Maine’s Penobscot River. PHOTO CREDIT: ©Mark Godfrey/TNC

Finally, a wide range of partners have collaborated to remove dams that have outlived their purpose, reconnecting rivers and restoring fish populations on rivers such as the Neversink (NY) and Elwha (WA).  The Klamath (CA) looms as the next big removal.  On the Penobscot River in Maine, a series of hydropower dams had blocked the upstream travel of the biggest runs of Atlantic salmon in the United States—along with 11 other migratory fish species—for more than a century.  In a breakthrough agreement, two of those dams have been removed, reconnecting nearly 1,000 miles of freshwater habitat. But by upgrading equipment and changing operations at the dams that remain, the Penobscot River basin will generate as much hydroelectric energy after dam removal as it did before, even as the river is transformed in terms of its value to migratory fish and to the people who depend on those fish – a case that offers a great lesson for countries undergoing development about the potential to find better balance the first time.

Rethink, re-operate, remove. Protect, restore, and reconnect. Redemption for rivers so fish can keep running, or start running through again.

Explore The Nature Conservancy’s latest thinking, science and recommendations on rivers and water conservation.


  1. Bell
    Belgium, Ciney
    June 28, 9:40 am

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    I’m satisfied that you shared this helpful information with us.
    Please keep us informed like this. Thanks for sharing.3384

  2. Steffen
    United Kingdom, Threapwood
    March 30, 1:06 am

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  3. Lorena
    Switzerland, Niedermuhlern
    January 19, 10:29 pm

    Awesome! Itts really awesome article, I have got much clear idea on the
    topc of from this piece of writing.

  4. Roger Wachtler
    June 8, 2016, 6:31 pm

    Please watch the award winning fims


    Return of the River

  5. Jenny T
    May 19, 2016, 3:02 pm

    New dams and artificial migration over dams in fish lifts?
    Come on TNC… you can’t make dams friendly. Focussing on one or two species of fish loses sight of the destructive impact a dam has on the entire watershed.

    Rethink? Yes
    Remove? Yes
    Re-operate? No
    Build more dams? No

  6. DamNation Film
    May 19, 2016, 2:36 pm

    We’re glad to see the benefits of dam removal highlighted in this article from The Nature Conservancy.

    However, as we promote and celebrate free-flowing rivers and fish passage, let’s not overstate the effectiveness of modifying or building new dams with high-tech fish passage facilitates. As observed around the world, and noted in a recent study posted by Yale University (attached below), engineered fish passage over dams is highly ineffective, does not provide passage for many non-target fish and other wildlife, and ignores the broader climate change and ecosystem solutions provided with dam removal.

    Instead of enabling new “smart” dam construction or putting band-aids on existing dams, we hope groups like The Nature Conservancy will instead focus on protecting and resorting free-flowing rivers and promoting more effective and lower impact water, energy, and flood protection alternatives.