A Rising Tide

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A Q&A with Olympia, Washington, city manager Steven Hall and public works director Michael Mucha

Olympia is Washington State's capital city. Will Olympia also become Washington's Atlantis? That's a stretch, but city officials there are increasingly concerned about rising sea levels as global warming melts polar ice. Olympia abuts Budd Inlet, a southern arm of Puget Sound where extreme tides are normal. Much of Olympia's downtown sits on low-lying land that may be sinking, due to tectonic forces, even as the water level is rising.

To find out how Olympia is planning for that future, I spoke with City Manager Steven Hall and Public Works Director Michael Mucha. They talked about the unexpected impacts rising seas would actually have on a coastal community such as Olympia, how the city is considering dealing with them, and how the issue of sea-level rise affected Olympia's debate about where to build a new city hall.

Christopher Swope: Is Olympia's sea-level rise problem any more pressing than in other coastal communities?

Steven Hall: I don't know if it's more pressing. It's just that we're getting out there quickly to understand what the impacts are and what we might do. Our community is pretty engaged around the whole climate change issue. We've been working on reducing our greenhouse gas emissions since the early 1990s, and we've actually reached the standards set in the Kyoto protocol.

We've done a lot of things related to greenhouse gases but we've also focused on one of the inevitable consequences of climate change, and that's sea-level rise. We have slides to show the likely impact on our downtown with a two-foot and then a three-foot sea-level rise. So we're beginning to assess the situation and we'll eventually take action to deal with it, although we're still debating at the policy level what that means.

Michael Mucha: It's important to know that with sea-level rise, it's not like it just rises and that's it. We have fairly major tidal influences in South Puget Sound--our water level can fluctuate by 20 feet twice a day just from the tides. Since we're at the end of Puget Sound, the tides are magnified. So when we talk about sea-level rise, we're talking about what happens during the highest tides, and when we have high winds. So the seas would just be up for a period of time-on occasion we'd have this kind of flooding.

Swope: It's interesting how you're describing the problem, because when one thinks of sea levels rising, it might call to mind water gently lapping higher up on the shore. But you're saying the problem is not so much higher water, but that you'll get more flooding during specific events.

Rising Sea Levels in Olympia

As sea levels rise, much of Olympia will find itself submerged. These images show the projected impact of sea level increases of, from left to right, one foot, two feet and three feet.

Mucha: It magnifies major climate events and natural events. The issue of sea-level rise is not just the melting of ice. As water temperature rises, there's thermal expansion globe wide, so the water actually has a higher volume. That's a lot of what contributes to sea-level rise--it's not just the melting ice packs. And then with the changing wind patterns, more water is pushing into the west coast. We're seeing prevailing winds push more water here-I call it the sloshing effect. And with subsidence, the south sound is sinking about a tenth of a foot in the next 50 to 100 years. So we have land going down, we have the water getting bigger, we have snow melt, and we have winds pushing the water around the globe in different ways. So it's a very complicated thing. And so when people ask how much are seas going to rise and I say three feet, it's based on a lot of assumptions and a lot of dynamics. Does anyone know? No. These are best guesses at this point. But we're looking at the climate scientists to help us.

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