Home Page
Link to Mayor McGinn Blog Home Link to Mayor McGinn Web Site Home Page Link to Mayor McGinn About Us Page Contact Us

Mayor Mike McGinn left office on January 1, 2014.
This website is for archival purposes only, and is no longer updated.

City of Seattle

March 6, 4:37 PM click here to comment > 5

Setting a new goal for Seattle’s stormwater management

Mayor McGinn today announced a new goal for managing Seattle’s stormwater runoff by detailing a new effort where polluted runoff will be increasingly managed using natural drainage systems rather than traditional pipe and tank systems.Mayor Green Stormwater 03 sm

The Mayor’s executive order—among the first of its kind in the nation— directs City departments to develop a coordinated approach to significantly increase the use of natural drainage systems to slow and clean polluted waters by filtering the water through vegetation and soil, much like a forest ecosystem does.

“Whenever possible, we should be looking for ways to better manage our stormwater with natural processes and leveraging our drainage investments,” the Mayor said today, announcing a new goal to manage 700 million gallons of stormwater annually with green stormwater infrastructure, by the year 2025. “Seattle residents and businesses care about the environment.  And that’s why we are inviting the whole community to join us in this effort.”

City Councilmembers have expressed support for  citywide green stormwater goal and the Mayor’s directive. Council will consider the goal in a resolution later this month.

“I am confident this initiative will be another success in the City’s groundbreaking environmental history” said Councilmember Jean Godden, “From implementing the first recycling program in the country to negotiating the first of its kind Consent Decree with the EPA to clean up our waterways once and for all, we’ve always been leaders in protecting our environment through smart choices and innovative solutions. I know our residents will be behind this effort.”

Councilmember Mike O’Brien added that relying on a distributed, green approach also builds flexibility and resilience into urban drainage systems to prepare for the uncertainties of climate change and is also well-aligned with other sustainability goals. “We can’t just focus on doing less harm,” he said. “It’s really time to leverage our stormwater investments to help us with other future-looking goals like tree canopy recovery, energy savings, and improving the pedestrian environment of our city. This is a big step in the right direction.”

“Green stormwater projects are high-value infrastructure investments that make our city more sustainable, and lay a strong foundation for meeting the city’s comprehensive planning goals,” said Councilmember Richard Conlin. “It’s absolutely critical that we are making sound investments that will continue to benefit our residents and our urban ecology for generations.”

“Seattle has long been a leader in the deployment of green infrastructure,” said Karen Hobbs, Senior Policy Analyst for the Natural Resources Defense Council. “The Mayor’s announcement not only lays a strong foundation for the city’s ongoing infrastructure planning efforts, but also will be a valuable example for other cities.”

The green stormwater goal will be achieved through a combination of City-led projects on public land, code-triggered private sector investments, and voluntary actions on private property. Given current population growth projections for Seattle, the goal works out to approximately 1,000 “green gallons” of green stormwater infrastructure-managed runoff per resident, per year, and represents about a six-fold increase over the amount of stormwater Seattle currently manages with green infrastructure.

Hundreds of millions of gallons of polluted stormwater runoff flow into Seattle’s creeks, lakes, and Puget Sound every year—runoff that contains bacteria from sewage overflows and toxins like petro-chemicals, pesticides, and heavy metals from our yards and cars.  Green stormwater infrastructure helps prevent this pollution by slowing the runoff and using natural systems to filter and clean the water close to where it falls as rain.

Green stormwater infrastructure approaches include bioretention swales, raingardens, stormwater cisterns, pervious pavement, and green roofs. Seattle has been a national leader in the development and application of these technologies for over a decade, and these approaches are now considered best management practices by the U.S. Environmental Protection Agency and Washington State Department of Ecology.

For more information on the city’s green stormwater infrastructure policy and goals, please contact Pam Emerson with the Seattle Office of Sustainability & Environment,, 206.386.4145.

Posted by: Words: April Thomas, Pictures: Jen Nance


Comment from George Cheung
Time March 13, 2013 at 10:15 am

This is absolutely a good and innovative ideas. I fully support it and it should be implemented as soon as possible. Clean water is vital not only to environment we all are living but also vital to the health for each individual.

Comment from Granger Michaelsen
Time March 13, 2013 at 10:25 am

I live at the 7200 block of 35th Avenue South on Beacon Hill. Much of the neighborhood area to the south (and up the hill) from me has no storm drainage system of the traditional pipe system variety.   Rather ditches at the roadside provide for storm water runoff.  This system has ongoing problems evidenced by erosion to the hillside on my property as well as silt and mud (and probable pollutants) running down 35th Avenue So. and entering the pipe and tank storm water system that apparently begins at the corner of So. Myrtle Place and 35th Ave. So. 

Given the Mayor’s plan: when will the city address the antiquated storm drainage system in this part of Seattle? (or the lack of one)

And with the Mayor’s announcement, will my neighborhood become more of (or a new) priority in the management of storm water management due to the leveraging of investments mentioned in his plan?  

Pingback from Sign up for College Bound Scholarships | Ethiopian Community In Seattle
Time March 14, 2013 at 12:24 am

[…] in good company. Setting a new goal for Seattle’s stormwater management Mayor McGinn announced a new goal for managing Seattle’s stormwater runoff by detailing a new effort where polluted runoff will be increasingly managed using natural […]

Comment from Mark-in-Seattle
Time March 14, 2013 at 7:41 pm

We are north Seattle residents, members of Sustainable Ballard who so wanted the raingardens SPU installed in Fall 2010 to have worked, instead most were dangerous ugly muddy ponds that never drained – a total technical and PR disaster. SPU said later they didn’t know the soil wouldn’t drain. Amnesia maybe since they drilled 6 deep bore soil tests and 22 soil trench tests BEFORE installing their muddy ponds. Nevermind, SPU’s public relations dept will say whatever fiction is necessary, hoping the public is gullible enough to believe it.

The original (93) raingarden cells cost $1.7 million dollars and only retained 35,000 gallons, costing $48 for EACH gallon or $2,400 to fill a 50 gallon rain-barrel. I know because I measured each darn cell during our rainy winter in 2011. This exorbitant initial cost doesn’t include the $350,000 to rip out the raingardens at 77th Street & 29th as demanded by residents after months of frustration trying to work with SPU to get the raingardens to work correctly. Hundreds of thousands more tax dollars have been spent filling in the Ballard bioswales with evermore biosoil, underdrains and more plants so they won’t become ponds for weeks on end, however, as a result of these cosmetic retrofits they don’t hold but a tiny fraction of water they did before, making them next to useless for stormwater detention purposes. At least in SPU management’s mind – mission accomplished, water-filled muddy ponds will not show up again as they did in 2011 on KOMO and KIRO TV. SPU claims it was all Federal Stimulus money as though that makes extravagant waste OK. Not true – $697,309 dollars is a loan at 2.9% interest due in 10 years, another large chunk came out the Seattle City general fund budget and the expensive retrofits and raingarden removal appears to be on the tab of Seattle ratepayers and taxpayers.

Recent research raises concern for a buildup of toxic levels of pollutants and pathogens remaining in the top soil layers of raingardens after several years of filtering. Germany now removes the top 6 inches of biosoil in raingardens after 5 years, disposing of it in hazardous waste landfills, then replants all the vegetation at great expense. Maybe that is the renewable part of GSI projects?

Combined sewer overflows are bad and must be managed, but raingardens are NOT a cost-effective solution given our Seattle glacial till soils, in my opinion. Cost-effective appears not to be a project characteristic SPU is concerned about since their revenue from water sales has declined in 29 out of the past 30 years and they need big capital CSO projects to backfill their agency budget.

WA-DOE just recently determined that residual toxics in raingardens are a serious concern and is seeking to ban installing underdrains in them because when the water drains too fast it leaves little time for the soil to de-activate the pollutants. SPU was planning on using underdrains in areas where soil doesn’t drain well – ie. most of Seattle with glacial till. So back to the drawing board, or full speed ahead?

Good news, there already is a great, affordable program at SPU; RainWise, that pays residents and businesses to capture and channel rainwater from roofs into cisterns to be released slowly after the rainstorm has passed. This program costs $5 -to- $7 per retained gallon, not $20 -to- $25 a gallon for redesigned raingardens nor $35,000,000 for 1 million gallon buried concrete tanks. SPU should expand RainWise and allow distributed cistern storage beside public right-of-way. Expand on what is working well first. It just needs encouragement to broaden it’s adoption in neighborhoods. Expensive raingardens are a PR smokescreen to distract us from SPU’s real solution; burying huge concrete tanks near CSO outfalls paid for with $700 million dollars of public debt, which are estimated to DOUBLE Seattle water bills in just 5 years. We residents already pay the highest (combined sewer and water) bills of any city our size in the country ! What will our well intentioned, but seriously mis-informed electeds say to Seattle citizens living on fixed incomes, when their water/sewer bills double in just a few years and go up another 30% two years following? Will they hold up photos of lovely green roadside raingardens and say … “green is good, go sit in the garden, eat a can of beans and calm down – have a great day!”,

Comment from Jaeteekae
Time March 30, 2013 at 1:32 am

Makes good sound bits but when Seattle is party to a billion gallons per month of Brightwater sewer effluent being discharged directly into Puget Sound, Salish Sea becomes Seattle Sewer!
This discharge is more acidic, warmer, oxygen depleted, salt-free, all detrimental to ocean marine life. And this does not even begin to address problems with drugs, hormones, heavy metals, chemicals, BOD load, etc that pass thru the treatment plant!
When will we get someone in EPA and WSDOE who actually knows what is going on and will really work to protect the Sound.
This effluent should be treated just like the mayor suggested treating storm water.
IF this effluent is as innocuous as WSDOE claimed when they patted themselves on the back for signing off on the permit, why isn’t it discharged into Lake Sammamish or Washington, where it is very much more compatible (fresh water)? At least land ponding like the mayor suggested. (Was NRDC just a lap dog for this travesty?)
At least it is free of oil and petroleum products.