A Washingtonian’s Guide to Snake River Salmon Geography

Chinook salmon leaping up Dagger Falls, Middle Fork of the Salmon, Idaho

If you live or play in the Pacific Northwest, you’ve probably heard of the controversy surrounding the four Lower Snake River dams and their devastating impacts on Idaho’s salmon and steelhead populations. Conservationists have argued for decades that these four dams must be removed if these fish are to recover. Republican congressman Mike Simpson of Idaho came to the same conclusion more recently. And just this week, Washington Senator Patty Murray and Governor Jay Inslee released a draft report concerning removal.

But despite all the recent attention and many excellent articles and resources, I find many people remain unclear on the fundamental geography of these rivers and dams. Washington residents especially are often not familiar with Idaho’s relevant (and confusing) geography. This page is my attempt to illustrate and clarify the terrain under discussion and to increase awareness of the remarkable wild river country beyond Washington’s eastern border.

So where exactly are we talking about?

Main Salmon River, Idaho

The area of fish habitat that would benefit from removal of the Lower Snake River dams encompasses most of central Idaho plus a respectable chunk of northeastern Oregon. We’re talking everything upstream of those four dams that does NOT have any other dams impeding fish passage. Sadly, and confusingly, this actually excludes most of the Snake River itself, which is dammed in Hells Canyon. It also excludes the North Fork of the Clearwater, which is blocked by Dworshak Dam. But this leaves a vast area and river mileage: the enormous and dam-free Salmon River drainage, the also quite sizeable Middle and South Clearwater, plus the Grande Ronde and Imnaha in Oregon.

The area looks approximately like this:

Let’s just superimpose that onto Washington:

Puget Sound to Idaho, Oregon to Canada – looks bigger already! This is the amount of fish habitat we’re talking about opening up again to the sea, approximately 26,000 square miles, a little bigger than West Virginia and larger than 75 of the world’s countries.

Here are a few other comparisons for anyone who may find them helpful:

Okay, fine, it’s big, but what’s actually there? Idaho is mostly potato farms, right?

Middle Fork Salmon canyon, Idaho

This area is mostly endless miles of deep river canyons, forest and rugged mountains. There’s a bit of farming, a bit more ranching, virtually no industry, but lots and lots of both legal and de facto wilderness. Excluding Lewiston and La Grande, the only substantial towns, both of which are on the area’s edges, the region’s population is about 50,000. This is a big, empty chunk of landscape.

And it’s full of wild, mostly unpolluted rivers. The Salmon and Clearwater fan out into a huge array of tributaries, most of them wild and healthy: the South Fork Salmon, the renowned Middle Fork, the North, East and Yankee Forks, the Secesh, the Pahsimeroi, the Lemhi, the Little Salmon, Rapid River, the South Fork Clearwater, the Lochsa and the unsurpassed Selway. Oregon’s Grande Ronde is fed by the Wallowa, Lostine, Minam and Wenaha. And each of these is fed by countless creeks, many of them nearly river-sized themselves. Most of these streams run cold and clear from high-elevation headwaters, with abundant cobble bar spawning beds waiting for fish that no longer arrive.

Cobble beds, Middle Fork of the Salmon

The region is also well-protected. The Selway, Lochsa, Main Salmon, Middle Fork, Rapid River, Imnaha, Lostine, Minam, Wenaha and Grande Ronde all have protections under the National Wild and Scenic Rivers System. And central Idaho has the largest complex of designated wilderness in the lower 48. This area once had huge fish populations and it could again be a major migratory fish stronghold if the salmon and steelhead could just get there.

If Idahoans are so concerned, why don’t they remove some of their own dams?

Selway River, Idaho

Which precise dams should they remove? I see this opinion expressed a lot in Washington, but it reveals a misunderstanding of the fundamental geography in play. Eight dams stand between the Salmon and Clearwater Rivers and the Pacific Ocean. Zero of those dams are in Idaho. The Salmon River drainage contains no dams at all, and only one Clearwater tributary is dammed. Fish on the John Day and Yakima Rivers only have to swim past three and four dams respectively, and they are doing much better than Idaho’s fish. Eight reservoirs is just too many. Dworshak Dam cut off some great fish habitat on the North Fork Clearwater, but removing it would achieve essentially nothing if the same eight dams are all standing downstream. And the rest of the Clearwater and Salmon drainages contain no dams at all – that’s why these drainages are so important as once and future habitat.

But the Hells Canyon Dams don’t even have fish ladders!

Rapid River, a Salmon tributary in the Hells Canyon region

Correct, but see above. The Hells Canyon dams did cut off some habitat (it was once even possible to catch salmon in northern Nevada), but again, improving fish passage there would make no difference with eight dams standing downstream.

A related point of confusion worth clarifying is that breaching the Lower Snake River Dams would not open habitat on the upper Snake and no one is claiming that it would. Breaching is intended to open habitat in the Clearwater and Salmon drainages, plus northeastern Oregon, which is much higher quality habitat anyway.

Crooked Creek, a tributary to Oregon’s Wenaha River

We should be working on pollution and fish habitat in Puget Sound!

I see this objection a lot from my congressional representative. Yes, we should. Puget Sound is important salmon habitat and improvements there are definitely a good thing. But the Salmon-Clearwater region is too large and high-quality a habitat to write off. Let’s look at another image of the area superimposed on western Washington this time:

Imagine the Olympic Peninsula, Puget Sound, the entire Central Cascades, Mount Rainier and the Goat Rocks and the Yakima Basin all being cut off from ocean connection. That is the scale of the ecological opportunity lost in Idaho due to the Lower Snake dams. Salmon are not so abundant in the Lower 48 that we can afford to give up on a habitat of this size and quality.

And remember, Puget Sound is full of people and industry. Central Idaho is not. It is far less polluted and better protected. The Frank Church, Selway-Bitterroot, Gospel Hump, Hells Canyon, Wenaha-Tucannon and Eagle Cap Wildernesses amount to over 4 million acres of protected landscape, waterways and headwaters. For comparison, all the Wilderness Areas of the Washington Cascades (and they are big) total 3,360,070 acres. In terms of American salmon habitat, cutting off Idaho from the sea was in many ways comparable to cutting off western Washington. We can’t afford to lose this region!

Middle Fork of the Salmon, Idaho

There’s also the issue of fairness to our neighbors and to Native Americans. People in Puget Sound would not react well to being told to give up on salmon and orcas because they can go see them in Alaska. Well, people in Idaho likewise should not be told to travel to the coast to fish for salmon that were once abundant in their own backyard. And our nation promised the Nez Perce people fishing rights in their own homeland. Washingtonians should be better neighbors and acknowledge that these four dams greatly diminish Idaho ecology and recreation and Nez Perce heritage while mostly benefiting only southeast Washington.

Grand Salmon – Source to Sea paddle team meets with Nez Perce representatives in Lewiston, Idaho, June 11, 2022

But doesn’t climate change mean salmon are doomed anyway? And what about sea lion predation and overfishing?

Middle Fork Salmon headwaters, cool even in summer

Rising temperatures are precisely why we need Idaho as a salmon refuge. Thanks to high-elevation headwaters and swift flow, Idaho’s rivers are better able to stay cool all summer than lower, slower rivers to the west. Water temperatures in the Lower Snake and Columbia reservoirs are cooking migrating fish, but a free-flowing Snake giving access to high-quality, high-elevation habitat would significantly improve the picture.

And threats like increasing sea lion predation and commercial fishing issues are again precisely why we can’t afford to give up on the opportunity of Idaho’s vast and intact spawning habitat. All our northwestern salmon populations face these threats. To weather these challenges, we need more salmon refuges, not fewer.

The Salmon River, still big, wild and dam-free


I hope at least a few readers find this helpful. It is not intended to be a comprehensive guide to the issue – if you’re looking for a deeper dive, there are many excellent resources available, some of which I will link below. My intent has simply been to clarify the confusing geography and resulting misconceptions and emphasize why Idaho, a state without a coastline, is so important to salmon discussions. I also respect the importance of Washington’s agriculture and care a great deal about Palouse growers and the beautiful landscape they farm. They are my neighbors and I want them to thrive. But the limited benefits of the Lower Snake dams come at much too high a cost. For any Washingtonians who wish to see salmon thrive for future generations, the time to tell this to our Washington politicians is now, this summer.

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5 thoughts on “A Washingtonian’s Guide to Snake River Salmon Geography

    • Thank you, Matt! Right now it’s mostly Washingtonians who need to speak up, but I’d appreciate your keeping this one your radar – it’s definitely of national importance.

  1. I learned a lot through reading this, Jackson. Thank you for the time you put into it. This post is also a great example of how photographers can bring conservation issues to life by pairing this kind of narrative with photographs.

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