If you have lived in the West Seattle neighborhoods of Westwood or Sunrise Heights for several years, you might recall receiving postcards, letters or other mailings from King County about the Barton Combined Sewer Overflow (CSO) project. You’re busy, so you may not have read the information thoroughly. You also may not have been able to attend one of the few community meetings about the project.

Or maybe you even attended a meeting…but left not fully understanding the project because of all the technical language. Perhaps you visited the King County website for the project–but quickly got lost in all the jargon and lack of user-friendly information. This page will describe in plain language the Barton CSO project is and how it could impact you and your neighbors.

What’s a CSO?

King County defines CSOs as “discharges of untreated sewage and stormwater released directly into marine waters, lakes and rivers during heavy rainfall, when the sewers have reached their capacity.” There are many ways CSOs can be addressed–bioswales are only one of several possible options.

What’s a bioswale?

Bioretention swales / bioswales are NOT rain gardens.

King County described them as “planted areas engineered to capture stormwater runoff from streets and yards and infiltrate deep into the ground.” The County planned to construct the bioswales in the public right of way, in the planting strips between the curb of the street and the sidewalk.

In other words, bioswales are long, rectangular areas (some as wide as 15 feet and as long a 45 feet) intended to capture, hold and slowly release water. Webster’s Dictionary defines a ditch as: “a long narrow excavation dug in the earth, as for defense, drainage or irrigation.”

How will the bioswales be built / work?

On the King County website, we could never find a well-illustrated, simple and clear description of exactly how the proposed bioswales were supposed to work.

Based on what we learned from community meetings and conversations with County staff, our understanding is that work crews would need to drive heavy construction trucks and equipment into the neighborhood and jackhammer through the existing street to construct the largest bioswales–15 feet wide and up to 45 feet long.

Crews would excavate down at least five feet beneath planting strips to install pipe that connected the series of bioswales on your block. On some blocks, several bioswales could be lined up in a row. The work of laying pipe would include boring under trees–but in most cases would require complete tree removal.

Once the pipe was installed, layers of drainage materials, soils and vegetation that can survive in standing water would be planted in the swales. Stormwater runoff from streets, roofs, sidewalks and yards (including pollutants like phosphates, copper from car brakes, grease, soaps and pesticides) would enter the bioswales. The hope is that the organisms in the bioswale soil would filter out all of these pollutants.

Water in the bioswales would then be carried by a series of underground pipes to the end of the block and dispersed to the soils below. These deep soil layers were expected to drain well–unlike the impermeable glacial till or “hardpan” closer to the surface.

Of concern: how might drilling deep under the street next to our homes impact fragile clay sewer pipes in our old neighborhood? Does it make sense to dump huge volumes of water underground–which could destabilize soil or lead to sinkholes later?

Wait–I thought I was just getting nice landscaping in my planting strip?

So did we–initially. But this project’s goal was about storing water adjacent to your property and releasing it slowly to prevent sewer overflows. King County bioswales would convert the strip in front of your house into a stormwater treatment “facility.” If you had plantings in that area, they would be removed. If you had a small tree in that area, it would most likely be removed since trees can’t survive in standing water. Some trees might be added, but they would be placed awkwardly–almost flush with the sidewalk. And yes, the City of Seattle gives out trees to plant in this area–but King County would remove them for this project.

What do bioswales look like?

King County included photos in their promotional materials that showed flat, attractively planted strips of greenery with small “curb cuts”–gaps in the curb to allow water to enter and exit the swales. But then we learned in meetings and follow up interactions with King County that bioswales proposed for West Seattle would largely NOT have that design.

What would the bioswales for West Seattle look like?

To capture the large amount of water volume necessary to prevent overflows, many of the bioswales in West Seattle would require a design similar to those used in the failed Ballard rain gardens project (please see the Photos page).

The existing cement curb would be “bumped out,” so a bioswale could extend from the sidewalk as far as 15 FEET into the street and could be as long as 45 FEET. The County did not provide estimates for how steep the sides of the swales would be, but they would form a “V” shape. These larger swales would be designed to hold up to a FOOT of water. As well, on some blocks, the County planned to line up several of these big swales in a row, in front of one house after the other.

Because of the size of the swales and how far they extend into the street, they would likely need to feature prominent, tall “No Parking” signs and potentially gold and black diagonally striped hazard signs (please see the Photos page). Permanently, parking would be lost next to these larger swales.

In Ballard, this unattractive signage made the impacted neighborhoods look like permanent construction zones and negatively affected curb appeal and property values. In the impacted Ballard neighborhood, a real estate agent estimated that home values dropped by 15%. Incidentally, King County only provided one study about property value impact. The study did not include input by a single real estate agent and its findings were not based on the type of bioswales (the big ones that hold a lot of water) planned for Westwood and Sunrise Heights.

How long will these swales hold standing water?

King County said that bioretention swales are designed to infiltrate in less than 72 hours, and usually in 24 hours–after each rain event. In plain English, this means that during continuous days of rain, a foot of water would pool in bioswales for up to three days–or swales may constantly have standing water when it rains many days in a row. Our concern: This would create an ongoing drowning hazard. 

Children often find mud holes and puddles irresistible as play areas, but children can drown in as little as two inches of water, in a very short period of time. It deeply concerns us that drowning hazards would be intentionally placed in the right of way, in residential neighborhoods through which many children travel and live. In fact, bioswales were planned for construction next to Westside School which serves children of a variety of ages–including pre-kindergarten.

What if I have existing drainage problems on my property?

County reps initially said they would not construct bioswales in areas with existing drainage issues (e.g. wet basements, water sitting in the water meter / in the planting strip).  Then residents were told that existing water issues were not of concern and have no relation to the project.

Will the bioswales impact parking?

Yes. King County admitted that since the bioswales require bumping curbs out into the street, you cannot park next to them and you may not be able to park across the street from them, either. On some streets, up to seven bioswales were planned in a row–which means a significant number of residents suffered parking impacts.

Like many neighborhoods in Seattle, street parking can be tight. And alleys in the the neighborhoods to be impacted by bioswales are largely impassable. Street parking is typically the only option–unless you’re one of the few residents with a driveway.

What about emergency vehicles?

In the impacted Ballard neighborhood, residents saw a fire truck racing to an emergency slam on its brakes–because bioswales extended out into the street. The larger bioswales would leave just enough room for fire trucks to pass–with caution. Seconds count in an emergency–nothing should impair the passage of emergency vehicles! Even worse, large bioswales were planned at the ends of streets that had traffic circles–already a tight area for fire trucks to navigate.

How will cars safely pass one another on streets with large bioswales?

They can’t. On tight streets with big bioswales, if two cars were approaching each other, there may literally not be a place to pull over to let a car pass. One car might have to back up all the way down the street to let another car get past it — definitely a safety issue.

How do I cross the bioswale to get to and from the sidewalk and / or my house?

The bioswale design included low vegetation King County referred to as “steppables.” Our concern: The lack of a solid, paved and wide area to cross is unsafe–especially in wet weather. We spoke with Ballard residents who saw an able-bodied neighbor fall into a swale while trying to navigate across it. Some residents would need to navigate across the swales several times a day, and imagine doing so while carrying children, groceries, etc.

What about those with disabilities / limited mobility?

It greatly concerns us that a person using a wheelchair or a walker on the sidewalk could catch his or her mobility device on the soft edge of a bioswale–and fall in. Bioswales pose a danger to the most able-bodied citizens, so they are especially dangerous for citizens with limited mobility.

County project representatives asked impacted West Seattle residents if they had any current accessibility issues, but this approach was short-sighted. What if a resident breaks his or her leg and temporarily needs crutches? What if a resident develops a long-term disability a year after project completion? What if a person with a disability visits your home?

Once a bioswale went in, street parking in front of houses would be limited or may be prohibited entirely. This also means that you might be unable to sell your home to a person with a disability. And those with disabilities would be limited in the housing stock they can choose from / in which neighborhoods they can live. In addition to legal liability issues, we questioned whether the project took into account all of the requirements of the Americans with Disabilities Act (ADA).

The City of Seattle owns the parking strip, right?

Yes, the City owns that strip of land, but the City and County must show a “duty of care” in what they do with that area. A County rep mentioned that ordinances were being changed to allow for the construction of bioswales. That led us to believe that previously, building such a project in the planting strip would not have been authorized.

What does “duty of care” mean?

Duty of care is defined as: “obligation that a sensible person would use in the circumstances when acting towards others and the public. If the actions of a person are not made with watchfulness, attention, caution, and prudence, their actions are considered negligent.”

But rain gardens have worked in other places, haven’t they?

Actual rain gardens and bioswales can work and we support these. Their success depends on the setting and on how much water they’re expected to handle; green solutions for storm water have limitations.

King County often cites High Point as a great example of bioswales. Unlike the “retro-fit” approach of putting bioswales in an old, established neighborhood, High Point was built brand new from the ground up and includes permeable sidewalks, a retention pond and no accessibility challenges such as those discussed on this page. High Point has numerous cuts along the curb in the street and no big bump outs with all the street run off being funneled to one opening, like the Westwood and Sunrise Heights bioswales were proposed to have. As well, High Point residents chose to live in that neighborhood–bioswales were forced onto Westwood, Sunrise Heights and Ballard residents who already lived there.

Seattle’s Pinehurst neighborhood bioswales do not include the huge bump outs and unattractive signage planned for Westwood and Sunrise Heights. The Pinehurst project features bioswales that actually resemble the flatter, attractive designs being promoted in King County promotional materials because they don’t have to hold so much water.

For the Barton CSO project, King County planned to use a variety of methods borrowed from other projects. When we asked the County if they had done exactly what they planned for the Barton CSO project anywhere else–if they could cite a single example of where this exact project is up and working–they could not say “yes.” So like the Ballard rain gardens, the Barton CSO project as originally planned was an experiment–with taxpayer dollars, safety and health.

What went wrong with the Ballard rain gardens project?

The City of Seattle and Seattle Public Utilities (SPU) piloted a “rain gardens” program that was funded by Federal Stimulus funding. Construction began in Summer 2010.

The Ballard project used a prototype–a new, atypical design. Instead of traditional, flat rain gardens–they were bioswales, meant to hold large volumes of water. Due to the low permeability glacial till soil in the area and the lack of “under drains,” water collected in the bioswales and formed ditches that didn’t drain for weeks on end–or at all.

These ditches–full of standing water–spawned insects in the spring and summer and iced over in the winter. They attracted trash and pests.  They attracted children who saw them as play areas. Massive trucks had to vacuum out the water. Ballard residents built a website to document the problems, raised media attention and demanded resolution by the City. Finally, the City removed or in other ways addressed the issues–at a taxpayer cost of $500,000. You can learn more about the Ballard project on the Media page and also here:

But what happened in Ballard won’t happen in West Seattle, right?

King County said it wouldn’t. Representatives from the County said the Ballard project was done by the City of Seattle, not by King County. They said the Ballard project was rushed, that the City didn’t conduct proper soil analysis, and most of all, they said King County has “more time and money.” We remained skeptical.

First, West Seattle residents were told not to worry while the County took soil samples / conducted field analysis. The County found the same glacial till in our area that they found in Ballard. The County believed under drains and “deep infiltration wells” would ensure that the bioswales drain–while also telling us it may take up to three days for bioswales to drain after each rain event.

We’re concerned about how drilling deep under the street next to our homes might impact fragile clay sewer pipes in our old neighborhood. We’re also concerned that these “deep wells” are just large pipes that will dump huge volumes of water underground. Will this soil eventually become saturated, destabilize and lead to sinkholes later?

For the Barton CSO project, the County planned to use the large bioswale design used in Ballard. The County is also planning to borrow a variety of techniques from other CSO projects. As mentioned earlier, when we asked the County if they had done exactly that project anywhere else–if they could cite a single example of where that exact project was up and working–they could not say “yes.” So like Ballard, the Barton CSO project was likely to be another experiment–with taxpayer dollars, safety and health.

Have you raised these concerns with King County?

Repeatedly. We raised them in community meetings, in private meetings and in writing. King County never responded directly–either verbally or in writing–to our concerns about drowning or tripping hazards related to this project. They refused to address them directly as if these safety, health and liability issues didn’t exist, but the bottom line is that King County is legally liable if someone is hurt due to their installation of bioswales.

In April 2012, we requested in writing that King County provide homeowners with a written release–before construction began. This release would absolve us of any and all liability if and / or when someone is hurt due to the installation of bioswales and attendant new construction (placement of trees too close to the sidewalk, curb bump outs, etc.). We never received this release or a direct response to our request. We’ve carefully kept track of all of our efforts regarding this project with King County in the event that future liability issue arises due to this project.

Please see the Letters page to read the correspondence several concerned citizens sent to King County Executive, Dow Constantine. In the past, we supported Dow Constantine and believed he was a strong advocate for the environment. We couldn’t imagine he would want a legacy of creating health hazards in residential neighborhoods and wasting millions of tax dollars–but we were disappointed to never receive a personal response from him.

Clearly, the staff behind this project relished the idea of solving the CSO issue with a green project. And as Seattlelites, of course we fully support green building. But we could never support a project that sounded great on paper but in reality had dozens of unresolved questions that rendered the idea unsafe, unfair and untested.

How else can this problem be solved besides bioswales?

The best solution would be to address the actual problem–the old infrastructure which mixes sewer and stormwater. King County could separate these two systems.

Separating the lines would still require treating the stormwater runoff before releasing it into Puget Sound. King County could build a water storage facility with a carbon filtering system for the separated storm runoff. This treated water could either be released into Puget Sound or stored and then used for watering planting strips and parks during the dry season.

We do not know if bioswales can completely eliminate the Barton Station’s CSOs, anyway. But we do know that if a green solution is used, it must be built without creating hazardous conditions and removing trees. We recommended King County consider a simpler and more effective green solution. King County could have worked with and around existing planting strips by installing a drain system inside the planting strips–along the edges of the strips and between trees currently planted in the strips.

The drain system would consist of a gravel trench with a drain-pipe below. The trenches could then be covered with smooth surfaced pavers for solid footing but would still allow water to drain into the trench below. A carbon filter could be used to filter the runoff before it entered our gardens and released into the “deep wells” or into a park-located reservoir to be stored for summer use. The benefit of using a removable filter would be to monitor and prevent a buildup of toxins next to residential homes. An even simpler and possibly less expensive version of this plan would be to build gravel trenches at the street-curb edges and fit them with removable filters.

We’ve offered positive and effective green solutions–and we invite you to comment with your ideas, too.

Why isn’t King County using alternative CSO solutions in Westwood and Sunrise Heights?

Fixing the infrastructure and / or building storage tanks are safer, proven options. In fact, King County initially planned to put a decentralized water storage facility under a parking lot in West Seattle. The property owner of the affected business agreed. It is unclear exactly why King County then abandoned that option and switched to bioswales–but they said the bioswale option is greener–and less expensive.

We don’t believe removing established greenery or having pools of polluted standing water in residential areas is green. We also don’t think bioswales are less expensive–once people get hurt, the resulting lawsuits erase any cost savings.

There were also no guarantees that the project would work. Again, removing the failed bioswale project in Ballard cost taxpayers $500,000. So if the Barton CSO project went in as planned and failed, taxpayers would pay for removing bioswales and also for whatever solution the County used to replace bioswales. In short, tax payers would pay for the project twice.

We also found it very interesting that other neighborhoods with higher property taxes (e.g. North Beach CSO, South Magnolia CSO and Alki) received CSO options that don’t involve bioswales. These other areas received options that do not create any safety, health,  liability or access issues. The Barton CSO project is also an issue of environmental justice; neighborhoods with less political and financial clout should not receive a CSO solution rife with safety and health hazards and horrible aesthetics that impact quality of life and home value.

How do I find out if I’m getting a bioswale in front of my house or not?

King County says this project is complete. Along the way, they stopped calling the project “bioswales” and began to call them “roadside rain gardens.” You can see a map of the project area on the County’s website.

Thank goodness–I looked at the map on King County’s website–it says I don’t get a bioswale!

Please note how big the project area is. King County always described their maps as preliminary and said that before or after the project began, they might need to add, change or move the locations of the swales. In March 2013, the project was dramatically reduced to fifteen blocks with the potential to expand to four more, but to date, remains limited to those fifteen blocks.

Because the numbers continually changed, it increased our concerns and skepticism about the County’s plans. And we know their stated goal was to place swales throughout the city, so no one should feel that he or she is “safe” from this project.

Even those without a bioswale in front of their homes may still have to deal with  negative impacts including loss of street parking, impairment of an emergency vehicle trying to reach their home, unattractive signage and increased pests in the neighborhood. All of these issues could lead to lowered property values.

Bottom line–this project impacts your community. If you have concerns about the safety, accessibility or other issues this project could bring, even if you aren’t initially slated for a bioswale, it’s not fair that your neighbor down the street–or across town–should get one.

If I get a bioswale, who will maintain it? 

King County vows to manage and maintain the bioswales just as they would with one of their brick and mortar facilities. We would like to see a written guarantee to this effect. Even though the City of Seattle owns the strip in front of your home, who currently maintains it? Yes, you do. In areas where homeowners have not mowed the strips, have you seen how long the grass grows before someone from the City finally cuts it?

Currently, most parking strips are just grass, which  is easier to maintain than a landscaped area. The bioswales would contain water, pollutants and grasses. Trash and leaves will blow into them. Initial plantings will take time to grow, and the project will be exciting for the first one or two years. What happens in three years? Five years? Ten years? We are hopeful but find it difficult to believe the County will truly maintain these bioswales on a house by house basis indefinitely.

How did it all turn out in Westwood and Sunrise Heights? What do I do if King County proposes bioswales in my neighborhood?

All of our efforts ultimately led to a scaling back of the project area, and safer, more attractive, and flatter plantings on the affected blocks. Some parking and trees were lost, but had we not pushed back, we could have rows and rows of deep, unattractive ditches of standing water in front of our homes right now.

We ensured that King County understood that its residents are not going to take a bad idea like this lying down. If bioswales are proposed for your neighborhood, educate yourself, and if necessary, push back if you don’t fully understand or feel comfortable with the project truly being green or safe. Visit the Petition/Take Action page to find out how we asked residents to get involved.

6 Responses to Issues

  1. Larry Murante says:

    I agree with many of the concerns surrounding bioswales. I don’t know enough about the alternative options to know if they would be better, less experimental, or cost prohibitive. My understanding is that this work is being paid for by the feds as you stated. I am one of the homeowners who has totally planted in our strip. Our street, between Elmgrove and Thistle on 31st, is one of the major arteries of the CSO project. Before I join the 14 other petition signers, I would want to know that there is a better alternative. The gravel trench with drain pipe alternative you address in your statement is vague and hard to know if it would be less invasive and a better solution. Could you point me to some other sources so that I may follow up? Do you know if this has been done in other Seattle neighborhoods and how successful this alternative has been?

    Thanks for all your efforts. I have a feeling the ball is already rolling to fast and hard to stop it now. They have until the end of the year to have it all drawn up in order to get the money from the feds. Correct? I just can’t see a massive mobilization to turn it around by then. At the very least though, I would love to see some written confirmation that the county would be liable for injury due to the bioswales.


    Larry Murante

  2. Thank you for your thoughtful comments, Larry. If your home is slated for a bioswale, it’s sad to know that you’re likely to lose all the beautiful plantings you’ve put in your strip.

    We apologize if our information above about other ways to solve CSOs was not clear. The tried and true / best solution for solving CSOs is to address the actual problem–to fix the old infrastructure which mixes sewer and stormwater. King County could separate these two systems. The County could also build a storage facility to hold the water and release it after the danger of a CSO has passed. The drain pipe alternative option described above is just one of our thoughts about how the problem might be solved in a green way that doesn’t create a drowning, tripping or accessibility hazard.

    We are not clear on exactly when the County has to complete its design plans in order to get Federal funding. But we do know that funding for this project involves taxpayer dollars so we should all have a voice in what happens. Other neighborhoods are getting the infrastructure or water storage CSO solutions–but not Westwood and Sunrise Heights.

    It is not too late to insist on other CSO solutions in West Seattle. We need to lift our voices via the petition or other options listed on the Take Action page. We don’t know if we’ll be able to stop the biowswale option–but you can be certain it won’t stop if we suffer in silence. For more questions, feel free to also contact us anytime at

  3. Lee Ellis says:

    Thank you for developing this site, and to Larry for his well thought out comments. I’m so glad to live in a city where the residents air concerns, and aim to provide fact based, feasible alternatives, in a thoughtful manner. How did you get so smart on this issue, so fast?

    • We appreciate your comments, Lee. We first became intrigued and then concerned about the project a year ago, when soil sampling began. To get up to speed, we’ve attended public and private meetings with County staff, read lots of information online, scoured media reports and have communicated with Ballard residents. Even though we’ve learned a lot, we’re amazed at how many of our neighbors–and people all over Seattle–still don’t know about the project at all. We’re trying to share the full story via this site. Please spread the word to your friends, neighbors and co-workers if you can. Thanks!

  4. Holloway Hewatt says:

    We are experiencing the SAME ISSUES!!! I live in Kensington, MD. We are very upset. Our DEP will not answer questions and if they do it’s the same thing you said above–72 hour drainage, etc. We will have no parking, our soils don’t perc and they basically laugh in our face!! It’s a complete nightmare. I never even thought about the sinkholes. It’s an old neighborhood with clay pipes as well. I am in a state of shock.

    • Holloway, so sorry to hear this is happening to you! We’re hopeful some of the information on our site and the Ballard Raingardengue site will prove useful as you try to address this in your area. It really helped for us to organize our neighbors, attend meetings and speak up, do research, write letters, start this site, talk to others who dealt with similar projects and to reach out to media. Luckily with all the pressure–and probably due to budget and political concerns–the project slated for our neighborhood was scaled back and the design was changed to be less invasive than originally planned. It was overwhelming and stressful, but it really helped to educate ourselves and take action. Let us know how we can help.

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