NE Woodinville Duvall Road at NE 172nd Street Culvert Replacement Project
Project completed
Check out the smooth surface of this freshly paved section of NE Woodinville Duvall Road above the new concrete box culvert.
Status update
September 5, 2023
NE Woodinville Duvall Road is officially open.
We thank the community members for their patience during this major project.
Local access maintained on NE Woodinville Duvall Road and NE 172nd Street
All lanes of NE Woodinville Duvall Road are open to local traffic between W. Snoqualmie Valley Road and NE 172nd Street, and between Avondale Road NE and Old NE Woodinville Duvall Road.
Local access to NE 172nd Street will be maintained via NE Woodinville Duvall Road, east of the full construction closure (closer to West Snoqualmie Valley Road NE).
Overview
King County replaced a narrow, worn-out metal pipe culvert with a much larger and wider concrete box culvert under NE Woodinville Duvall Road at NE 172nd Street. We also removed a concrete fish barrier downstream of the culvert and restored 235 feet of Tuck Creek with more natural habitat. The new culvert and creek habitat restoration is designed to move water through at its natural pace, just like a real stream.
The limited work area required the county to close both directions of NE Woodinville Duvall Road from 7 a.m. Monday, July 17 through 11:59 p.m. Friday, August 25 to install the culvert underneath the road. Local access on NE Woodinville Duvall Road and NE 172nd Street was maintained during the closure. View traffic detour here JPG 375KB.
Why did King County replace this culvert?
We replaced the worn out, narrow metal culvert because it was rusted and failing.
The existing metal pipe culvert was nearing the end of its useful life and needed to be replaced. The old culvert was also considered a fish passage barrier. The new culvert is made of concrete and is also much wider to make it easier for fish to pass under the road.
This metal pipe culvert was considered a fish passage barrier for two main reasons:
- It was too small for the volume of water that passed through it. As a result, the water was pushed through extremely fast making it nearly impossible for fish to swim in it.
- At times, the water inside the existing culvert was too shallow and it was located too high above the stream bed for fish to jump into the culvert so they could not continue to swim upstream.
Fish have a very difficult time swimming through extremely swift water. They also have a lot of trouble jumping up and through a metal pipe with very little water in it.
Benefits of the concrete box culvert
A box culvert is flat and wide with streambed gravels placed in the bottom to simulate an actual stream allowing fish to move up and downstream easily. The new concrete box culvert makes it much easier for fish in Tuck Creek to pass under the roadway and continue their migration to Snoqualmie River.
- The box culvert can accommodate a much larger volume of water.
- It is designed to simulate a natural stream and allow consistent, gentle water flow under the road.
Fish have a hard time migrating upstream if there is not enough water in the culvert, or if the culvert is too high above the stream. The box culvert helps make it easier for fish to pass underneath the road. (Image courtesy of King County Fish Passage Program).

Culverts may block fish migration because the water flow is too swift, too shallow, or has a waterfall into or out of the culvert. The new box culvert is designed to have enough water running through it at a natural pace, just like a real stream. (Image courtesy of WSDOT Fish Passage Program).
An aerial view of the project location prior to construction. NE Woodinville Duvall Road at NE 172nd Street was closed for 40 days in a row, including weekends from July 17 through August 25, 2023. Larger view PDF 354KB
The old 8-foot-wide metal pipe culvert carried Tuck Creek under NE Woodinville Duvall Road (shown above). This culvert is a fish passage barrier and had outlived its useful life. The county replaced it with a much larger, fish-friendly box culvert in 2023.
The project also removed the 50-foot-long concrete fishway barrier (above) and restored the creek so that fish migrating upstream don’t have to jump up and over the rocks. (Photo taken: September 2019)
Budget and funding sources
The preliminary estimated total project cost is $4.5 million. This project is funded through the King County Fish Passage Program which is supported by local funding sources.
Frequently asked questions
It took 40 days to remove the old pipe and install the new box culvert under the road.
The 40-day full road closure also significantly reduced the total cost of the project and guaranteed both lanes of Woodinville Duvall Road are open in time for the start of the 2023/24 school year.
Most fish barriers in unincorporated King County are large round metal pipes (culverts) that channel streams and water underneath the road. Many of these culverts were installed between 30 and 100 years ago. These older metal culverts allow water to flow but are so narrow and steep that they prevent fish from swimming through them.
The ability of salmon and steelhead to swim upstream to their traditional spawning grounds is vital to their recovery across Washington and King County. Deteriorating culverts and other barriers block fish passage and undermine the state and county recovery efforts.
One of the most effective ways to ensure the survival of native fish – and the southern resident orcas that rely on them as a food source – is to remove barriers to their habitat.
- Chinook Salmon
- Coho Salmon
- Chum Salmon
- Pink Salmon
- Steelhead Trout
- Cutthroat Trout
Photos
Work to dig out the old, failing culvert began in early August and took several days longer than anticipated to remove, which has caused delays. This photo was taken on Aug. 1. The culvert was eventually fully removed on Aug. 7.
Aug. 23, 2023 – Crews roll over the smooth surface of the freshly paved section of NE Woodinville Duvall Road above the new concrete box culvert.
Aug. 22, 2023 – Trees and rocks fill the downstream section of Tuck Creek leading to the new box culvert. The new culvert and creek habitat restoration is designed to move water through at its natural pace, just like a natural stream.
Aug. 23, 2023 – A view from above the new box culvert shows the safety guardrail with the creek flowing freely below it.
Aug. 10, 2023 - Our team is making progress every day towards reopening NE Woodinville Duvall Road. The culvert concrete is carefully poured between wall sections of the new culvert to secure them in place and prevent leaks.
Aug. 10, 2023 - The walls and floor of the new box culvert are in place. Next up is the concrete lid which will be placed by a crane. Once the culvert is complete, it will be filled with dirt, gravel, rocks, and native plants to make a healthy habitat for fish and other creatures.
Aug. 11, 2023 - An excavator works to ready the new stream bed between the retaining walls on either side of the new box culvert. The bed will be filled with dirt, gravel, rocks, and native plants.
July 31, 2023 - It takes several crewmembers to pour the concrete for the large retaining wall running along NE Woodinville Duvall Road .
August 5, 2023 - A crewmember uses a smaller excavator in the deep construction pit after shoring has been placed to allow for construction of the foundation of the box culvert. The foundation is covered with a thick liner, rocks, and dirt to make a safe passageway for water and fish.
August 4, 2023 - Two large excavators sit at both sides of the large construction pit in the middle of NE Woodinville Duvall Road. This pit makes the road impassible so all travlers need to use the detour route.
August 5, 2023 - A big truck dumps rocks into the bottom of the excavation to construct the foundation for the new box culvert.
Environmental staff are temporarily redirecting fish away from the workzone so that crews can safely install a temporary stream diversion for fish to use during construction. Specialized crews catch and release fish downstream and then install a stream diversion to redirect fish until the project is complete. (Photo July 2023)
Crews install a large four-chamber water cleaning and containment system known as a baker tank. The tank helps to keep the worksite dry and cleans the water around the construction zone. (Photo July 2023)
Crews scrape back multiple layers of old pavement from NE Woodinville Duvall Road before excavators are brought in to dig a large construction pit in its place. (Photo July 2023)
This is the existing metal pipe culvert looking upstream. Most of the year the water moves very fast through the metal pipe into the stream. Over time this high-intensity, swift water created a drop between the culvert and the streambed. This hole prevents fish from being able to jump high enough into the culvert so they can continue to swim further upstream. (Photo May 2019)
A closer look at the existing metal culvert that carries Tuck Creek under NE Woodinville Duvall Road at 172nd Street. This culvert is rusted out along the bottom. (Photo: September 2019)
View of the concrete fishway looking downstream from the existing culvert pipe. This fishway was installed in the 1980’s to help migrating fish. Fish that use this ladder mostly swim upstream. The fishway is considered a partial fish barrier because the far end of the fishway (where fish enter) is too high above the stream. (Photo taken: September 2019)