My article that was posted on May 26, 2016 entitled “Wait a Minute – Raw Sewage in Lake Union?” received quite a few interesting and insightful comments and additional questions. Apparently one of the readers of that article was Andy Ryan who is the Media Relations Coordinator for the Seattle Public Utilities and Andy was kind enough to provide us with some answers to the questions that were raised in the article and in some of the comments. So I have included those questions and Andy’s responses to those questions below.
Did past increases in Seattle’s density increase CSOs?
Yes. In general, combined sewer flows are mainly storm water (90 percent) and to a smaller degree of sewer water (10 percent). In 
the past, density did add additional storm water to the flow.
Will CSOs become more frequent with new development?
No. The City of Seattle’s storm water code says that all new development needs to take care of its storm water onsite (via underground detention, infiltration, etc.). New development needs to take care of its storm water that had been entering the combined sewer is now held back or is treated and directed to the separated storm system.
How does the Long Term Control Plan’s Ship Canal Water Quality Project address the future?
The Ship Canal Water Quality Project was sized to accommodate the combined flows from basins in Ballard, Fremont, Queen Anne and Wallingford. It has been sized to fully control the area’s outfalls and has factored in climate change impacts. Because of the City of Seattle’s storm water code, all new development (HALA-related or independent) is required to take care of their storm water on site.
Are there other ways that Seattle Public Utilities is preparing its wastewater systems for the future?
Yes. Later this year, Seattle Public Utilities will begin developing a Wastewater Master Plan. This Plan will create solutions for capacity constrained wastewater locations throughout the City and will plan for increasingly strict water quality regulations, climate change and development. The Wastewater Master Plan’s public engagement plan hasn’t been developed yet, but there will be opportunities to participate.
Does new development impact Seattle Public Utilities in other ways besides CSOs?
Yes. Seattle Public Utilities provides drinking water, recycling services and sewer and drainage infrastructure to all residents and businesses in Seattle.
Once again, I want to thank Andy Ryan for his thoughtful input and answers to the questions and to all of those who took the time to comment on my May 26 article. Andy Ryan can be reached at [email protected] if you have any need to contact him.
I quizzed someone about this during a CSO tunnel presentation to WCC a ways back. A 5 unit project completed on my block last year didn’t handle its own runoff, I surmised because they were allowed to subdivide their lot into 2 lots with 2 and 3 units, thus evading requirements that come with scale thresholds. The SPU rep asserted that standards had been tightened since then, but we didn’t get into any details. In any case there is some scale threshold, and some of the housing types they’re pushing will fall under that scale – for example backyard cottages, required to install runoff diversion cisterns? Not likely. For larger developments, they can point to standards, but historically they have allowed developers to get around them via dodges like those subdivisions.
Andy, thanks for your response but you’ve got to do more. The developer with the new house and the remodeling and additions say they had no idea about the Rainwise program.
Thanks, Donn. We need to keep city officials know that we are watching.
A major concern I have with the incredible pace of development here has been the loss of tree canopy, open space and green places. With teardowns – whether single family homes or old multiplexes or with the addition of front and backyard “cottages”, there is an inevitable loss of trees – especially mature and evergreen trees: the troublemakers for developers. Whether the replacement property is a huge home or an apodment, the whole lot is built out to the lot line with little or no opportunity for any natural environment.
Trees provide huge benefits in water retention, habitat preservation, air and water quality and filtration, noise mitigation, shade, beauty and human well-being. Requiring underground storage tanks for water retention when our native trees perform this function exquisitely seems an exercise in short term gain and long term loss.
Although the city sponsors an urban tree management plan and asserts that the tree canopy should be increased, it is not counting, monitoring or enforcing this vital element of our urban life. Every new development creates significant tree and habitat losses. Meanwhile, the city is neither promoting or developing new parks or open spaces within densifying neighborhoods to address or mitigate these losses.
Our neighborhood is a joy to walk through because of the care and attention our mostly middle-income, long term residents pay to their gardens and homes. I feel such deep gratitude to these generous folks who enrich my life every single day with their charming, generous and health-promoting outdooor spaces. I have heard some density promoters deride the notion of gardens, yards and outdoor habitats in the city. This, more than anything, is the big reveal to me.
In fact, the 2035 Comprehensive Plan would remove the specific protections for trees, that are in the Land Use element of the current Comprehensive Plan.
I think it is fair to give the City a chance to respond. However, we must remember that 1.14 billion gallons of untreated combined sewage overflowed into Seattle waterways in 2014 (most recent data). I think it is more than reasonable that we require our sewers to have enough capacity before we upzone. The fixes for the NW CSO basins will not be completed until 2030.
I understand that new construction standards have methods in place for controlling stormwater. But the whole equation needs to be looked at. If you take away an old tree and replace it with a green roof, which is better at mitigating runoff? If you greatly increase the lot coverage (impervious surfaces) but add in storm water mitigation, which is better? If you replace one older toilet that uses more water with 15 new toilets that use less water, which is better? And again, where do the townhomes & backyard cottages fit into the equation, if they are not required to do the same mitigations? We have to look at the whole picture. It just does not pass the common sense test that more development will somehow reduce pollution,.
Susanna,
All new construction (and some remodels) must comply with green stormwater requirements.
(A friend, who is having trouble logging onto Wallyhood, asked me to post his response)…
Susanna, great questions!
In regard to the effect of newly constructed units during overflow periods (including the additional flow from their toilets, sinks, washing machines, dishwashers, etc.) the rainwater will in fact flow into their respective city mandated internal detention vaults but it’s my understanding that the sewage and the “grey water” from the above sources will still flow into the combined sewers and add to the overflow when it occurs. Yes it appears that all will be fixed by the giant 2.7 mile tunnel but it’s not planned to be finished before 2030. It appears that these new units will make the contamination of Lake Union worse until the tunnel is finished in 14 years. Is that acceptable?
These follow-ups from Glenn, which I do wish were part of his first post, show the extent to which this is a non-issue with regards to HALA.
As we discussed on the earlier post… As the city finally got serious about the problem, the overflows have decreased substantially even as population and housing units have increased.
2010: 189,996,720 gallons overflow – 46.99 inches rainfall – 4,043,343 gallons/rain-inch
2011: 78,194,356 overflow- 36.39 rainfall – 2,148,786 gallons/rain-inch
2012: 154,232,337 overflow – 48.26 rainfall – 3,195,862 gallons/rain-inch
2013: 37,497,450 overflow – 32.56 rainfall – 1,151,641 gallons/rain-inch
2014: 115,586,683 overflow – 48.50 rainfall – 2,383,230 gallons/rain-inch
While 2014 had 33% more rain than 2011, it had only an 11% increase in outflow. And while 2014 had 3% more rain that 2010, it had a 41% decrease in outflow. 2013 had 11% less rain than 2011, but 46% less outflow.
The outflows have been occurring since Seattle started building sewers, about 100 years, so this is not a *new* problem. The city has (finally) prioritized this and is building retaining systems to bring us into full compliance *and* in the meantime has significantly reduced the problem.
“The Ship Canal Water Quality Project was sized to accommodate the combined flows from basins in Ballard, Fremont, Queen Anne and Wallingford.”
By “project” does he mean the current construction going on over in Fremont? Or does he mean the end result of the project over a decade from now? My understanding of the current construction project, which if I recall correctly Eric referred to as the “sh*t tube”, it does not serve Wallingford and that there is a second phase of the project well over a decade from now that will make sure our sewage stops going into Lake Union during heavy rain events. No one disagrees that the problem will eventually be fixed but the timeline for that is still many years out.
Glenn,
Thanks for the post! I appreciate you making the effort to go directly to the source of the information.
However, there are two important points missing from the conversation. First, the primary source of water pollution in Puget Sound is not storm water run off from roofs but stormwater runoff from streets and parking lots laden with petroleum products and heavy metals from cars.
http://www.pugetsoundstartshere.org/
https://fortress.wa.gov/ecy/publications/documents/0710058.pdf
To express concern about new buildings while ignoring or even promoting (by mandating on street parking) increased use of the automobile confounds the problem and its solution.
Second, people will be housed SOMEWHERE. If not with increased density within Seattle it will be in lower density and more car dependent locations with an even greater negative impact on water quality due to more roof and impervious paved area. This a regional problem, not a local one.
Seattle isn’t the only city in the world, or even in the Pacific Northwest. The notion that everyone will end up here, is absolutely fictional and counterproductive; the result is what we see, despite frenzied construction we’re driving people who work here out into outlying areas. Which is indeed bad for everyone, but the answer isn’t to pretend we can put unlimited numbers of people up inside the city limits, it is to start making it possible for people to live and work in other cities in the region.
Donn,
Agreed. Seattle is not the only city nor can it accommodate all of the growth. Other cities are also seeing growth and rising rents with it. Tacoma rents are rising faster than Seattle’s although starting at a lower point.
http://www.thenewstribune.com/news/business/article62265967.html
Almost as many folks live in Snohomish, Pierce and Thurston Counties combined as live in King County. The problem is that 40% of them drive into King County to work to the tune of one million vehicle miles A DAY. The good news is that we are in trend toward urbanization (thanks in part to the GMA) and we’re gradually improving our regional transit infrastructure. However, we need to consolidate population growth.
This will take many forms including the urbanization of suburban communities and increased density in cities like Everrett, Tacoma, Bellevue, Olympia AND Seattle. While Bellevue (Redmond) has robust employment none of these cities come close to Seattle in terms of employment opportunities. Thus, at this time, it makes sense for Seattle to accommodate the bulk of the growth.
I agree that better regional planning might better distribute the employment throughout the region but that requires a centralization of planning authority that makes many in this state uncomfortable (I’d be delighted to see it happen). Regarding Seattle, the central question is should >60% of the city’s land area continue to be devoted to relatively low densities even when it has good access to transit and services. I say no. Others disagree. OK, time to clean the house.
Expedia moving from Bellevue to Seattle, for example, along with 4000 employees? Is that not a terrible public policy failure? I am confident it could it have been prevented without any central state planning authority, but first we need public officials with a more responsible attitude towards growth.
So whose failure is it – Seattle’s or Bellevue’s? Without stronger regional planning we pit jurisdictions against one another with ‘winners’ and ‘losers’. I’m not convinced it can be achieved without greater cooperation and that comes from a more centralized planning authority. I wish it weren’t so but history and current conditions suggest that it is.
Maybe many of the employees will move to Seattle and maybe it will spur development in Interbay but, without that, we’re in agreement – it’s a cluster.
If we had the slightest evidence that anyone downtown would dream of discouraging a large corporation from moving here, then where to go from there would be an interesting discussion. If there’s room for thousands more units in Interbay without displacing industrial uses, there are people already working here to live in them.
Q. Will CSOs become more frequent with new development?
A. No. The City of Seattle’s storm water code says that all new development needs to take care of its storm water onsite (via underground detention, infiltration, etc.).
I don’t believe it. I see moderate impervious coverage lots with lots of trees being replaced with cheap (and ugly) 250 sq ft apartment boxes covering most of the lot. Where is the storm water retention on these projects? Where is info on City monitoring of the effectiveness of these provisions?
Here’s the “Before”.
My understanding of the 2016 SPU update is that projects under 10,000 square feet of new or renewed lot coverage (any SF property in Wally that is upzoned to MF will be 4000 sq ft if one lot or 8000 sq ft if combining two lots for the majority of Wally lots) are exempt from handling all of their storm water runoff onsite. It would be great if someone could confirm this with SPU.
Regardless, new development (assuming it has more units than what was there previously) WILL add sewage to the existing system, which for west Wally, Fremont, and Ballard means a higher concentration of sewage in the overflow water when an overflow happens.
I disagree with the folks that say that HALA will have no adverse effect on the overflows. You are adding more sewage to the existing system while not reducing runoff. It seems prudent to at least examine the environmental impacts rather than brushing them off as “not significant”. Such a review is required, as far as I know, by SEPA and should be done for both the HALA and the Seattle 2035 proposals.
According to the City of Seattle Stormwater Manual, for a lot created before 1/1/16, any project with 1,500+ sf of new and replaced hard surface or any project with 7,000+ sf of land disturbing activity must do on-site stormwater management. For a lot created after 1/1/16 that first number drops to 750+ sf of new and replaced hard surface.
The 10,000 sf number you’re referring to may come from the exemption that projects with less than 10,000 sf of new and replaced rooftop surfaces don’t have to evaluate their site for rainwater harvesting. But they still have to evaluate it for full dispersion, infiltration trenches, dry wells, rain gardens, infiltrating bioretention, and on down the list.
http://www.seattle.gov/dpd/cs/groups/pan/@pan/documents/web_informational/p2358283.pdf