Surprising Applications of Perturbation Theory

This past week I gave public comment in the Idaho Governor’s “Salmon Working Group” meeting. The working group is composed of a bunch of different industry and nonprofit members who are collectively trying to restore a thriving population of salmon in Idaho, specifically the Snake River Watershed.

The Snake River drains into the Columbia near the Tri-Cities area of Washington, so it’s an integral part of the Pacific Northwest ecosystem. Plenty of folks from Washington, Oregon, Idaho and even British Columbia gave comment.

I’m copying my commentary here as an example of how you can take ideas from physics and use them to get a broader message across. It’s also interesting to see how our education frames our perspective on all kinds of problems - and why policy work needs a diverse set of perspectives.

One of the goals of the Pasayten Institute is to bring a diverse set of folks - and their ideas - together in a context of Physics education, research and outreach. We also strongly believe that the outdoors presents a great scaffold for such a diverse group ideas. So it’s always good to revisit our context and keep abreast of what’s happening in your broader, ecological neighborhood.

Hi everyone, My name is Sean, pleased to meet you! Thank you so much for taking my comment. I live in Washington State, in the Methow river valley. First off, thanks to everyone here for doing the hard work of trying to come up with a way to save our region’s fish.

The Methow watershed that I call home drains into the OTHER fork of the Columbia. But, during normal times I travel all around the Pacific Northwest for work and for recreation. Your leadership will have a big impact on all of us down stream. So, again, thank you for your work.

Now, I’m a physicist. And as a physicist, we build models for all kinds of problems. Folks sometimes deride our models as too simple minded.  I’ve heard all the jokes. “Assuming as Spherical Cow” is the usual one. But that’s just how we think about big problems. From the big ideas… to the small details.

In physics we’ve developed a tool for successfully dealing with these kinds of complex problems. That tool is called perturbation theory. Perturbation theory means finding a “rough draft” solution to a simplified system, and adding in the details a little at a time, until you get a better and better representation of the physical system.

The only problem with perturbation theory is it can only improve that “rough draft solution” by a small amount. Otherwise, the tiny changes would by no means be tiny. The challenge in using perturbation theory is starting with he correct “rough draft” model.

For the problem of trying to recovery our salmon runs, I’m concerned that excluding the option of the immediate breaching of the four lower snake river dams is throwing out an important “rough draft” option. And as such, it’s just not taking the problem seriously. 

I’d argue that you’re missing the big solution for the big recovery, the recovery to abundance. I’m worried that any other options are only small perturbations that will ultimately not solve the problems before us all.

The mission statement of this working group is ambitious. Restoring abundant, sustainable and well-distributed populations of salmon and steelhead is a tall ask. You just can’t do that with small perturbations. We need to start talking about breaching those dams.

Thank you for the time, and thank you for your work.