Fauntleroy Creek Culverts Replacement Project (45th Ave SW)
Spawning salmon in Fauntleroy Creek. Photo courtesy of Whitney Fraser
Project description
Promoting a healthy urban watershed in your neighborhood.
Fauntleroy Creek is in southwest Seattle and drains a 149-acre area (.23 square mile) - called the Fauntleroy Watershed - into Puget Sound.
There are three culverts which allow the creek to flow under roads along Fauntleroy Creek: lower culvert at Fauntleroy Way SW, middle culvert at 45th Ave SW, and upper culvert at California Ave SW. The Fauntleroy Way culvert includes a fish ladder that was replaced in the late 1990's and is not part of this project.
The culvert at 45th Ave SW is the immediate focus of this project. The upstream culvert at California Ave SW includes both the publicly owned roadway culvert and a privately owned culvert beneath the parking lot of Fauntleroy Church, United Church of Christ. SPU and the Church are continuing to meet to discuss the requirements and needs of both parties. At this time, SPU is moving forward with the design at the 45th Ave SW culvert, and taking more time to explore potential work on the California Ave SW culvert.
SPU prioritizes culvert projects based on the likelihood and consequences of culvert failure. Each culvert is evaluated using various criteria, including impacts to the environment, traffic, and community, as well as operations and maintenance. Through this evaluation process, SPU has identified the public roadway culverts at 45th Ave SW and California Ave SW as high priorities for replacement.
The primary intent of this project is to prevent the risk of catastrophic failure of the roadway culverts and the associated potential impacts to public safety, roadway infrastructure, and the environment. Because repairing the public culverts is not a viable strategy due to their age and condition, SPU is committed to proactively replacing its public culverts to reduce risk of culvert failure and mitigate storm-related flooding.
Location
The culvert for immediate replacement is located at 45th Ave SW (near SW Wildwood Pl). The upstream culvert, under discussion between SPU and Fauntleroy Church, is located at California Ave SW (near SW Brace Point Dr).
What's happening now?
The project's Options Analysis Phase is complete. In 2021, the preliminary design of the 45th Ave SW culvert received approval to move forward with design.
SPU is setting up consultant services to support design completion. Once the consultant team is onboarded in 2023, we will advance through our design process for the 45th Ave SW culvert.
The culvert system at California Ave SW includes both the publicly owned roadway culvert and privately owned culvert beneath the parking lot of Fauntleroy Church, United Church of Christ. SPU and the Church are continuing to meet to discuss the requirements and needs of both parties. Currently, the design of the California Ave SW culvert is on hold.
SPU continues to investigate creek, drainage, sediment, utility, or other infrastructure issues within the Fauntleroy Creek drainage basin that may be addressed through this or other projects.
Community benefits
The primary intent of the project is to prevent the risk of catastrophic failure of the roadway culverts and the associated potential impacts to health, public safety, and the environment. The project's goals and opportunities also include:
- Reducing the risk of culvert failure
- Improve creek resiliency to higher flows from anticipated climate change
- Restoring fish passage, which supports tribal treaty rights and SPU's commitment to racial and social justice
- Considering community safety in culvert design
- Enhancing the community's connection to the Fauntleroy watershed
- Providing safer working conditions for maintenance crews
What does the preliminary design look like for the 45th Ave SW culvert?
The 45th Ave SW culvert design is in the initial concept stages. Below are images of the preliminary design and concept sketch for the 45th Ave SW culvert.
Please note that we are still in early design, and the final design is subject to change based on permitting requirements and Tribal feedback, community input, and coordination with property owners.
A map of the 45th Ave SW culvert showing preliminary design for the proposed culvert.
Concept sketch of the culvert at 45th Ave SW.
- In the plan view above, we are looking down on the site as if we were up in the air. The new culvert is shown in blue, and the new creek alignment is shown by the blue dashed line. The new culvert is all below ground, as the creek is about 30 feet below the surface in the deep ravine. After construction, the surface will generally look the same as it does now, except with new pavement and other surface improvements.
- The culvert will be 14 feet wide and at least 6 feet tall. The size of the new structure was determined by collecting existing creek data and using the Washington Department of Fish and Wildlife culvert sizing calculations, which accounts for climate change. This larger size will allow the creek to meander more naturally, which will support a healthy habitat and fish passage.
- The new culvert has a slight curve that allows it to be more aligned to the public right-of-way. Compared to a culvert with an angle or bend, the curved alignment is preferred by Tribes and regulatory agencies. The curved alignment allows us to locate the culvert entrance on public property, unlike the upstream end of the existing culvert, which is on private property. The new alignment is expected to cross underneath private property, and SPU will work with the property owners accordingly.
- SPU is proposing to add public amenities that will enhance the community's connection to Fauntleroy Creek. These amenities may include public walkways, overlooks of the creek, and informational signage. Stay tuned for future opportunities to share your thoughts on these public amenities.
- In our earlier community outreach, SPU heard concerns about safety regarding future access to the new culverts. Some community members have expressed concerns that the larger culvert size will enable unauthorized use of the culverts. SPU is applying Crime Prevention through Environmental Design principles to the culvert design to deter unauthorized use. We are working to balance community safety, the need for our crews to safely access the culverts for maintenance work, and federal and state requirements for the culvert size to support fish passage.
Community engagement
Beginning with the Options Analysis phase in 2018, we have met with many community members and hosted briefings in the neighborhood to introduce the project and gather feedback. We are continuing to seek community feedback to inform the early design phase of the project and have been in conversation with Fauntleroy Church leadership to discuss the culvert system at California Ave SW.
If you are interested in receiving updates about future opportunities for engagement, please subscribe to the project email list.
Past work
- Evaluate suitable alternatives to replace the culverts
- Coordination with the community and Fauntleroy Church on replacement options, opportunities to provide feedback
- Recommend options to advance into design and/or for assessment of feasibility and cost refinement
- Complete geotechnical investigations
- Complete land surveying
- Preliminary design development for recommended options, cost estimate revisions
2021
- Gather community feedback on design elements like fencing, paving, and interpretive signage at the proposed public overlooks.
- Perform additional analyses such as hydraulic modeling and stormwater impacts.
- Perform detailed design on features such as creek channel design, wall and culvert structure design and roadway features.
- Determine additional property needs and initiate appropriate agreements.
- Apply for local, State, and Federal permits (regulating bodies include but are not limited to: Seattle Department of Transportation, Washington Department of Fish and Wildlife and the United States Army Corps of Engineers, in consultation with Tribal nations).
- Continued discussions with nearby businesses and homeowners including neighbors with property adjacent the creek/City right of way and Fauntleroy Church.
- Continue to hone cost estimates for the project and identify external funding opportunities.
At this time, design is anticipated to continue into 2023, with construction of the 45th Ave SW culvert anticipated in 2026 to 2027. Construction of the California Ave SW culvert would follow agreements on design between SPU and Fauntleroy Church.
Existing culverts in poor structural condition
Like many cities across the country, we are faced with having to repair and replace a lot of aging infrastructure. SPU prioritizes culvert projects based on the likelihood and consequences of culvert failure. Each culvert is evaluated using several criteria, including impacts to the environment, traffic, and community, as well as operations and maintenance.
Through this evaluation process, SPU has identified its public roadway culverts at 45th Ave SW and California Ave SW as high priorities for replacement. Repairing the public culverts is not a viable strategy due to their age and condition. SPU is committed to proactively replacing its public culverts to reduce risk of culvert failure and mitigate storm-related flooding.
Existing culverts are barriers to fish passage
The culverts at 45th Avenue SW and California Avenue SW prevent fish passage in Fauntleroy Creek. In replacing its public culverts, SPU is removing barriers that prevent fish from accessing upstream habitat. Stream conditions in the middle and upper reaches of Fauntleroy Creek have been characterized as viable fish habitat by SPU fish biologists, independent consultants, and biologists from the Washington Department of Fish and Wildlife (WDFW).
While relatively small, Fauntleroy Creek watershed is in a healthier condition than most of the City's urban streams — it has good water quality, ample forest canopy cover, the protection of City ownership for most of its area, and excellent community stewardship. Compared to other watersheds in Seattle, Fauntleroy Creek has the low levels of poor-quality fish habitat and a lot of moderate quality habitat that can be restored. It also has the lowest pre-spawn Coho salmon mortality of all our urban creeks, which is a strong indication of good water quality.
Based on stream surveys, nearly all of the mainstem of the creek up into Fauntleroy Park was identified as "Type F" waters (this means fish-bearing or capable of supporting fish.) New culverts on Type F waters need to be designed to meet state and federal requirements for fish passage. The new culverts would be sized based on WDFW Stream Crossing Guidelines to meet fish passage criteria, which will likely require a larger size for the culvert replacements.
Restoring fish passage is critical to support tribal treaty rights
Culverts are also related to tribal treaty rights. Many tribal nations signed treaties in the 1800s which guaranteed the continuation of their existing rights to hunt and fish in all of their usual and accustomed areas. These treaties, and subsequent federal court rulings which upheld these rights, were based on a presumption that the federal government would be a caretaker and steward of these lands, so that fish would remain plentiful. Over the last 150 years, federal, state, and local governments have not been accountable to those treaties, and they have not adequately protected fish and fish habitat. As a public agency, SPU is committed to restoring fish passage and supporting tribal rights and regional salmon recovery efforts.