Taylor Creek Early Work Projects
While the alternative designs for the creek restoration are being evaluated, SPU has decided to move ahead with design for two less impactful but still very important components of the project. These early work projects are smaller scale and can be constructed independently of the larger creek restoration project.
Lakeridge Park Slope Stabilization
If you’ve walked the pedestrian trail recently, you’ve probably noticed evidence of slope movement in the canyon. Over the last few years, SPU has been looking at ways to stabilize these slopes and prevent further damage to the trail and underlying sewer line. Because of the location, we had planned to complete the work as part of the larger Taylor Creek project. However, because the creek restoration design has been delayed while we evaluate alternative options, we’re moving the slope stabilization work forward separately and hope to complete it on a quicker timeline.
Map of slope movement
West
East
Project Background
SPU has a 1,900-ft long sewer line that runs along the west side of Dead Horse Canyon to carry sewage from a community in the southeast City limits. When the sewer line was installed, SPU created the gravel hiking trail that is beloved by park users today. The two pedestrian footbridges were also installed to help carry the sewer line over Taylor Creek and drainage culverts.
Project Problem
We have observed slope failures in 2009 and 2022 in Dead Horse Canyon. To put it simply, our sewer line, the pedestrian trail, and creek are threatened by the potential of an active landslide. Previous geotechnical investigations predict that the likelihood of another slide occurring is estimated at 20% each year. An active slide could damage our sewer line, cause service outages to our customers, and send sewage into the creek. This scenario, besides causing ecological damage due to spilled sewage, would require an invasive and costly emergency construction project to fix. We are seeking to mitigate these risks by stabilizing the slopes.
Project Solution
To help stabilize the slopes in the canyon, SPU is planning to install two separate micropile walls on the east and west side of the creek.
A micropile is a reinforced concrete pile that is drilled and cast in place to anchor into deeper, more stable soils. A concrete cap is then poured to connect the piles together and form a wall. The wall extends through many soil layers and provides stability that prevents the upper layers of soils from continuing to move. Once the walls are completed, they are completely buried and not visible from the surface. They also don’t require any ongoing maintenance or disturbance to the park.
Locations of two micropiles on east and west side of creek
Construction impacts – what do we know so far?
Micropile work doesn’t require heavy machinery, and it’s likely our contractor will be able to bring in small equipment using the existing pedestrian trail. We’re currently anticipating construction will only take up to four months, but it will cause intermittent or ongoing closures to the trail during that time.
This project will also impact some trees in the canyon, which we’re learning more about. We know protecting the forest ecosystem is extremely important to the community, and we want to be very transparent about any potential impacts.
We hired a professional arborist to review our design plans and survey the trees in the canyon to help us better understand potential impacts to trees. A draft version of the initial arborist report is available now. In brief, the arborist’s report concluded that 6 trees will need to be removed since they’re directly in the work zone and 2 more will be fatally impacted because they will experience more than 35% critical root zone damage. However, those 2 trees are proposed to be left standing to become habitat features.
Please note that the report is still draft and does not yet have SPU or Parks’ comments incorporated. Any tree that is removed will be replaced with five new trees, and any area impacted by construction will be restored and re-vegetated in accordance with Seattle Parks & Recreation’s best practices.
Schedule
We are currently working towards 60% design and anticipate having our arborist report completed this spring. Construction of this project is anticipated as soon as 2026, with all work taking place during the dry season.
Stay in Touch
Sign up for our listserv and check out the Taylor Creek project webpage to stay up to date as we share more information about this project in the coming months. In the meantime, if you have any questions, please reach out to Katie Wilson, Project Manager, at Katie.Wilson@seattle.gov.
Taylor Creek Outfall Improvements
Project Background
Work to improve two existing stormwater outfalls at the top of Dead Horse Canyon was recently separated from the larger Taylor Creek Restoration project. The improvements will help reduce erosion in the canyon and reduce the amount of sediment in Taylor Creek. Separating the outfall work allows SPU to construct them in advance of the larger project.
Project Problem
There are two outfalls on the east rim of Dead Horse Canyon that discharge stormwater directly onto the slope, causing significant erosion and sediment input into the creek.
Existing outfall at Rustic Road
Map of outfalls at Rustic Road and Crestwood Drive
Construction impacts – what we know now
Construction for this work does not require heavy machinery and will not require tree removal in Dead Horse Canyon. We expect construction to take up to three months to complete.
Schedule
SPU is currently working on the 90% design for the outfalls. SPU estimates construction will occur in summer 2026.
Project Solution
SPU is planning to tightline the two outfalls and make improvements to their structures at the top of the slope to help deliver stormwater to Taylor Creek without continued erosion and sedimentation. A tightline is a semi-flexible surface pipe that can lay down upon the slope, allowing stormwater to reach the creek without eroding the canyon.
Tightline example