Visiting Seattle’s off-limits watershed to learn about climate change

This pipe high overhead carries much of Seattle's water supply through the part of the Cedar River watershed
This pipe high overhead carries much of Seattle's water supply through the part of the Cedar River watershed

Republishing Guidelines

Yes, unless otherwise noted, you’re welcome to republish InvestigateWest’s original articles and photographs for free, as long as you follow a few simple conditions:

  • You must credit both the author and InvestigateWest in the byline. We prefer: “Author Name, InvestigateWest.”
  • You have to include the tagline provided at the end of the article, which typically reads, “InvestigateWest (investigatewest.org) is an independent news nonprofit dedicated to investigative journalism in the Pacific Northwest. Visit investigatewest.org/newsletters to sign up for weekly updates.”
  • You can write your own headlines as long as they accurately reflect the story.
  • You may not edit our work except to reflect your own editorial style or to update time references (changing “yesterday” to “last week,” for instance).
  • You may use InvestigateWest artwork (photos, illustrations, etc.) ONLY if you publish them alongside the stories with which they originally appeared and do not alter them. You may not separate multimedia elements for standalone use.
  • If you share our stories on social media, we’d appreciate it if you tag us in your posts.

Keep in mind: InvestigateWest sometimes republishes articles from other news outlets and we have no authority to grant republication permission. These stories are identifiable by their bylines and other credits.

We send story alerts to editors at news outlets across the Northwest. Let us know if you want to be included on that list. Questions? Contact us at editors@investigatewest.org.

Copy this

Showing remarkable foresight, Seattle voters in 1889 approved a plan to launch a city-run water system to bring water to the city from the Cedar River watershed. The water system started operating in 1901. Today the city owns the watershed and restricts public access. But now we’re learning the limits of this investment as climate change worsens.

In late August, Robert McClure visited the Chester Morse Reservoir with Seattle Public Utilities' Ralph Naess and Alex Chen and photographer Paul Joseph Brown.

Once known as Cedar Lake, this body of water created by damming the Cedar River is now the Chester Morse Reservoir, the largest of two reservoirs serving Seattle. InvestigateWest revealed that the amount of water Seattleites can count on could be reduced by as much as half over the next 35 years and nearly three-quarters by the end of the century.

Lying atop a once-natural lake known as Cedar Lake, Chester Morse Reservoir was created by damming the Cedar River. Despite the reservoir's enormous storage capacity, new climate-change projections suggest it will not be enough to meet water demand in Seattle as climate change progresses.

The Masonry Dam at the west end of Chester Morse Reservoir was built between 1911 and 1914 but has never been able to hold as much water as intended, in part because the water leaks out through a moraine left by a glacier.

The water lever is dropping lower in the Chester Morse Reservoir, where Seattle Public Utilities is installing a new set of pumps to help move water to Seattle in dry years.

The water level is dropping lower in the reservoir. But it would be even lower had SPU not altered normal operations to hold back extra water in the spring in anticipation of the current drought. Seattle and the Northwest saw snowpack plunge this year, in many areas to less than 10 percent of normal, followed by a spring with relatively little rain and an extremely hot early summer.

These pumps, purchased used by Seattle Public Utilities in the 1980s, are reconditioned in August in anticipation of low water levels this fall. When the Chester Morse Reservoir drops low enough, they are needed to get water to Seattle

These pumps originally went into service in 1980 in southern Washington after the Mount St. Helens volcano erupted, moving water that was dammed by the debris flow. Seattle Public Utilities purchased them several years later to move water over a hump at the bottom of the Chester Morse Reservoir that otherwise would keep water from running downhill to Seattle in low-water years.

Powered by diesel, the temporary pumps are being replaced with another more permanent diesel-powered setup to be used in low-water years to keep Seattle taps supplied. This roadway allows workers access to the reservoir this summer for work they are doing to install the new set of pumps.

This pipe high overhead carries much of Seattle's water supply through the part of the Cedar River watershed

A water-delivery pipe high overhead near Cedar Falls is part of an elaborate water-delivery system constructed beginning late in the 1800s, when Seattle helped pioneer the idea of municipally owned utilities. Despite substantial investments in the system over the last century, it is not clear it will be able to deliver under the conditions expected as climate change worsens.

Seattle Public Utilities Director of Water Planning Alex Chen walks and talks with Ralph Naess, the utility's Cedar River watershed public and cultural programs manager

Strolling past Cedar Falls, Seattle Public Utilities’ water-planning director Alex Chen chats with Ralph Naess, the utility’s watershed public and cultural programs manager. The city has gone to great lengths to protect its water supply, purchasing 91,000 acres -- virtually the entire upper Cedar River watershed -- and prohibiting most public access: Cedar Falls is off-limits to the general public.

Alex Chen, director of water planning for Seattle Public Utilities, high above the Chester Morse Reservoir

Alex Chen, director of water planning for Seattle Public Utilities, high above the Chester Morse Reservoir, is doing a lot of thinking about climate change nowadays. “How are the demand and supply lines going to cross, and when?” he asks as we drove around the watershed.

Get the inside scoop in your inbox, free.

Subscribe to our weekly newsletters and never miss an investigation.

Great! You’ve successfully signed up.

Welcome back! You've successfully signed in.

You've successfully subscribed to InvestigateWest.

Success! Check your email for magic link to sign-in.

Success! Your billing info has been updated.

Your billing was not updated.