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SPU's plan to get Seattle out of deep sh*t

Last year, Seattle spilled more than 154 million gallons of stormwater and untreated sewage into our lakes and streams. SPU plans to fix that.

The steps on the scaffolding are steep and slippery in the rain. Slowly we navigate downward to an underground tank that will eventually hold 2 million gallons of raw sewage and polluted stormwater overflow to keep it from entering Lake Washington. Last year, more than 154 million gallons overflowed from city-owned pipes into all of the city’s dozen water bodies and, with it, 8,000 tons of toxic metals and volatile chemicals.

Click on the audio player above or here to listen.

Seattle is one of nearly 800 U.S. cities that uses a combined sewer system, which collects rainwater, industrial wastewater and raw sewage in one set of pipes. Built in times of smaller populations and less use, combined sewer systems often overflow during heavy rain or storms, shunting extra wastewater and sewage into nearby bodies of water.  

Here on Lake Washington, Seattle Public Utilities (SPU) is building the tank to stop the city’s highest frequency overflow. In 2012 pipes in the basin on the western flank of the lake — which includes View Ridge, U Village and Sand Point — overflowed 149 times.

A map, updated hourly, of sewer overflows in Northeast Seattle on January 14th, 2014. Photo: King County 

"Once the tank is used, we'll be able to operate and control this whole tank from back in our operations and control center down in Sodo," says Keith Ward, an engineer with Seattle Public Utilities. "And when the storm is over, we'll pump the combined sewage back up 65th, down Sandpoint Way and back into the system." 

Real time controls and underground pipes will carry the toxic overflow to King County’s treatment plant at Discovery Park.  

Roughly 20 feet deep, the tank has three vaults for odor control and massive amounts of electrical, instrumentation, controls and steel. Construction manager Dennis Davis of CDM Smith points to layers of rebar reinforcing the construction.

Lake Washington's Windermere Basin tank will hold 2 million gallons of wastewater when complete. Photo: SPU/ Susan Stoltzfus

"This is going to have a massive tipping bucket. This is what we're all waiting for — when they test this tipping bucket and it comes roaring down here and then washes this out," said Davis. The bucket, which was designed to work in both stormy and dry weather, will be filled with fresh water to clean out the holding tank. 

The tank can handle 2 million gallons of stormwater, but since an estimated 47 million gallons overflowed into Lake Washington last year, it may need to operate continuously during big storms. Those generally happen only two or three times a year.

"The idea is when there's a big storm, we fill up this tank. We let the storm go out, we pump it back into the system. If there's another big storm we fill up the tank," said Ward.

The Windermere Basin tank — which hasn’t been given a name just yet — will cost the city $50 million and will be just one of a larger system of tanks dealing with Seattle's stormwater runoff and pollution problem, which violates the Clean Water Act. Their construction comes on the heels of years of water quality and public health violations, penalties and compliance orders issued by state and federal regulators.

In 2012 alone, there were 355 overflow events in the city’s 12 receiving waters. One hundred forty nine of those were in Lake Washington. Salmon Bay had 96, which spilled some 59 million gallons of polluted stormwater and sewage. Several years ago, one Seward Park storm caused a million gallons of sewage and stormwater to overflow.

SPU began excavation on the Windermere Basin tank a few years ago to show good faith to regulators, says Ward. Since 2001, the agency has also been working to contain the stormwater problem with rain gardens, retrofits and green infrastructure.


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Comments:

Posted Sat, Jan 18, 5:56 a.m. Inappropriate

The County's cost for the CSO program, in addition to the Seattle version is going estimated at 770 million dollars. Hold on to your wallets, wait until you hear what the estimates are for the 911 call center consolidation and radio upgrades. Dow is trying to force the Transit taxes before the rest of the taxing Tsunami hits the fan.

Cameron

Posted Sat, Jan 18, 9:45 a.m. Inappropriate

Uh, I think we are in trouble if the SPU guys quoted don't know that you pump WATER and lift SEWAGE. They say they will pump it back out.

I hope not, I hope they LIFT it.

Geezer

Posted Sat, Jan 18, 2:11 p.m. Inappropriate

Urban Containment' and overzoning zealots please note:

"[B]ecause the pipes weren’t built for 154 million gallons of stormwater, when it rains in Seattle and it mixes with the sewage it's going to overflow because that’s the release mechanism for the system when its overwhelmed.

Add a 20 percent jump in population from 1960 to the present, Growth Management Act mandates which require high density development in cities rather than urban sprawl, too few urban trees to absorb and contain runoff, and you've arrived at Seattle's new normal; a place where holding tanks and tipping buckets are required to — well — keep the shit from hitting the fan."

The energy embodied in existing infrastructure is not an assumable asset when its removal is a negative and its modification, an increase in the new energy expended. Perchance the 1990s Growth Management Act's assumption of perpetual economic growth is itself a rapidly antiquating thought?

afreeman

Posted Sat, Jan 18, 2:26 p.m. Inappropriate

P.S. As revealed by the chart on page 3 of the newly released January 2014 Background Report for the forthcomin Seattle Comprehensive Plan Update: a 20% 'jump' in Seattle's population is increasingly smaller potatoes with respect to impacted marine waters, the GMA not withstanding.

http://www.seattle.gov/dpd/cs/groups/pan/@pan/documents/web_informational/p2112855.pdf

afreeman

Posted Sat, Jan 18, 10:52 p.m. Inappropriate

The media is not supposed to be a cheerleader for the government and its agencies. This article smells of a re-write of the SPU's press release. It doesn't ask the questions: should we wait until the combined sewage/storm water overflows the system or can we somehow slow down the in-flow of storm water? Just tiny breaks in the concrete/asphalt would allow storm water from flowing into the combined stormwater/sewers. In the Sewerd Park area, many of the houses' drain pipes are illegally hooked into the sewer pipes; simply allowing them to flow into the substantial yards of the houses would greatly reduce the flow into the combined pipes--perhaps enough to prevent overflow into Lake Washington. Look at your own numbers: New York is overflowing 2 BILLION and Seattle is overflowing 200 million (a tenth). And we are required to stop this immediately. The entire run-off retention stinks of a giant 'make-work' project for the bureaucrats of SPU and the contractors. Small, affordable answers are available, but they will not be considered until the people demand a sensible and affordable approach rather than 'the most expensive possible answer'.

Posted Mon, Jan 20, 12:01 p.m. Inappropriate

Good point. The "tank" is analogous to using a giant vacuum cleaner to remove pollutants from Interstate 5 and then, of course, pumping the carbon monoxide underground to be dealt with at a later date.

In the author's defense she does say "Since 2001, the agency has also been working to contain the stormwater problem with rain gardens, retrofits and green infrastructure." As you point out the big money goes to well connected power players.

kieth

Posted Tue, Jan 21, 9:52 a.m. Inappropriate

Yes. Infrastructure costs money. What would be a more appropriate solution that's cheaper? I am actually curious, but I've been trained to be pretty pessimistic that these comments come from a place of genuine interest in solving the underlying problem.

Sorry, but I hear a lot of people make snide comments about infrastructure project costs, but to me they all sound like, "Jeez, FIRST I have to pay for bread, and THEN even MORE for toilet paper! Hang on to your wallets!" I don't hear them say why we don't need to buy bread and TP, and I don't hear viable ideas for how to stay fed and clean without bread and TP. I just hear them saying "but that costs money!"

Yes, basic infrastructure costs money. If we don't do CSO, we keep dumping poop and heavy metals into our water. That's just how it is. We haven't fixed that. Our options are: do something or do nothing. Assuming you're in the "do something" camp, yes, we will need to open our wallets and pay for something. Once we elect to do something, we have some choices for HOW to do it. But they all have to RESULT in the same thing: We STOP dumping poop and heavy metals into our water. That's what we need to have happen. And that's not free. In fact, it's more expensive than what we are doing (which is dumping poop and heavy metals into our water).

If we don't fund transit, we won't have any or we'll have less. Yes, there is a thing called inflation and yes it applies to the public sector. It costs more now than it did then. Health care inflation affects the price of a bus driver's wage and benefits. Just like yours and mine. Construction materials are getting more expensive (faster than core inflation, for the record). Buses and trains are getting more expensive. The infrastructure handles more people, is more complex, and has a higher cost.

What's the alternative? Cut transit? We've done that twice. Cut wages or benefits? We've done that too. What are we cutting them to? Do those cutting have an idea of an appropriate level to cut to? Or is the underlying philosophy simply "make it cheaper?"

nullbull

Posted Wed, Jan 22, 1:45 p.m. Inappropriate

"... dumping poop and heavy metals into our water.." I think the point falkenbury was making was that controlling the effluent near the source seems more promising and was, for years, part of the public mantra. I am curious why that is being supplanted by this giant holding tank . You should be too. Ms. Baskin does not explain how the toxic material is separated (presumably at the West Point Plant which I was unaware could handle heavy metals). The control of carbon monoxide and particulate matter is accomplished at our cars and trucks not at some giant facility that cleans air. Each vehicle has to meet emission standards; we have a model there that works pretty well. It's not cheap but it seems like a better model for cleaning things up than at the macro level.

kieth

Posted Thu, Jan 23, 2:54 p.m. Inappropriate

Not all of our storm runoff needs to go into the sewers, which would leave more capacity for processing waste solids and materials.

We could make sure that homeowners are directing their gutter downspouts into their permeable surfaces rather than into the side sewers. We could make sure that commercial construction includes permeable surfaces in at least a portion of their parking lots. We could even reengineer some of our streets to include permeable surfaces to try to absorb water back into the ground rather than shunting it directly into a drain.

We can be investing in infrastructure like the above to reduce the amount of stormwater that is overwhelming our ability to process it, or we can invest in infrastructure that directs rainwater into the ground rather than mixing it with solids that need to be treated.

I'd rather see us spend $500 million to keep as much rain water out of the sewer system as possible.

talisker

Posted Tue, Jan 21, 1:46 p.m. Inappropriate

Remember growth pays for itself, according to King County and the City of Seattle in the 1990's, to accomodate in extra infrastructure, I believe its part of the Growth Management Act when a developer applies for an Environmental Impact Statement. But if you don't enforce it, the rest of us pay, and pay, and pay. Sh*t is getting old.

salmonjim

Posted Tue, Jan 21, 3:45 p.m. Inappropriate

Stuff that gets old must be replaced. Forcing developers to pay for that makes no sense either.

Growth doesn't pay for itself, nor should it. We all know taxes pay for everything, including waste.

Reduce the waste, and save money.

Posted Tue, Jan 21, 3:44 p.m. Inappropriate

The Windermere Basin tank doesn't have a name yet? Seems like the name is the Windermere Basin tank.

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