Climate change pushing water system upgrades

Feb 12, 2013

Global climate change is a reality that few people now deny. 2012 was the warmest year on record. So what about Seattle’s water supply? 

Managers say they need to speed up about $30-million of investment in a backup plan.

Snowpack in the crest of the Cascade Mountains provides storage for Seattle's Cedar River watershed. Lowering snow levels are expected because of global warming, putting the supply at risk.
Snowpack in the crest of the Cascade Mountains provides storage for Seattle's Cedar River watershed. Lowering snow levels are expected because of global warming, putting the supply at risk.
Credit Courtsey Seattle Public Utilities

About two thirds of Seattle’s water comes from one of the most pristine sources in the nation. The Cedar River Watershed lies in more than 90,000 acres of protected land southeast of the city, near North Bend.

“This is an incredible jewel, a resource for the people of the city of Seattle and we are lucky to have it,” says Ralph Naess.

Naess leads drinking water discovery tours for Seattle Public Utilities. The watershed is in a preserve on land Seattle bought from timber barons more than a century ago, to create the public water system.

“As you can see, there’s no factories, no houses, no homes, no industry,” Naess says, as he stands above the 100-year-old masonry Dam on the Cedar River, between the two reservoirs that hold most of Seattle’s water supply.

He says Seattle is one of just six large utilities in the United States that can provide unfiltered water. It comes from snow pack in the mountains. Looking up at it, Naess says global warming could radically alter the system, as the snow level drops.

“That’s right now at probably about 3,000 feet.  So imagine in 50 years, you’d look up there and see no snow at all.”

As climate change plays out, the biggest risk for Seattle is more frequent and longer episodes of drought. Naess says when the reservoirs drain too low, the water gets stuck in the upper reservoir and gravity can’t do its job.

“So we have to have a way to get it out. And we have right now some emergency pumps that – they’re very old. And they need to be replaced with a system that we feel is completely reliable and up to the modern standards.”

Global warming is making replacement of the old pumps more urgent. Paul Fleming, who manages SPU’s climate and sustainability group, helps the utility stay ahead of the curve on these issues. He says even though our water source is relatively protected, more frequent and longer droughts could come faster than we think.

“We’re not immune from those problems and we have to understand both how things may change here and ultimately how our interconnectedness may mean that we’re going to see problems that maybe didn’t start here," Fleming says.  "There’s a whole host of unknowns that I think climate change is going to create.”

For now, though, he says we can consider ourselves lucky. Because the $30 million they estimate is needed for new emergency pumps is a lot less than the billions needed for climate change mitigation by water utilities in places like Las Vegas or San Diego.