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Sep
25

NE Woodinville Duvall Road at NE 172nd Street Culvert Replacement Project

 

Smooth surface of freshly paved section of NE Woodinville Duvall Road above the new concrete box culvert.

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. 

View project photos

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24/7 Road Helpline

Call us for help at 206-477-8100 or 1-800-527-6237 with road maintenance and traffic safety issues in unincorporated King County — 24 hours a day

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). 

Occasional lane restrictions in October

Flaggers will occasionally alternate traffic into one lane after the 40-day full road closure. The one-lane restriction allows crews and equipment enough room to safely move in and out of the work zone.

Project location

Map of NE Woodinville Duvall Road at NE 172nd Street in Cottage Lake, west of Duvall, WA.  

NE Woodinville Duvall Road at NE 172nd Street in Cottage Lake, west of Duvall, WA.

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 passage before and after culvert replacement graphic.

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).

Cartoon style graphic showing fish attempt to jump in culvert that is too small, high and in water that is too shallow.
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).


Aerial view of project location.

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


Existing culvert.

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.


Concrete fishway barrier on the existing culvert.

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.

Project timeline

  • January 2023 – Advertised to contractors
  • Mid-July 2023 – Construction begins on July 17, 2023, with 40-day road closure
  • Late-August 2023 – Both lanes reopen at 11:59 p.m. on August 25, 2023.
  • Late August/early September 2023 – Major construction ends
  • October 2023 – Project complete

Frequently asked questions

NE Woodinville Duvall Road at NE 172nd Street is too narrow to have enough room for a large construction crane and other necessary equipment while safely maintaining even a single lane of alternating traffic through the work area. There are no shoulders to store equipment.

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.
Drivers added 20-30 minutes of extra travel time. We recommended using a real-time driving directions, live traffic and road conditions app or online tool to get on-demand travel time estimates.
No. There was an open construction pit in the road for the first 40 days of this project. It was not safe for any vehicles or foot traffic to use the road when it was closed for this kind of construction work. We coordinated with emergency responders to minimize additional response time during the closure period. 
If you plan to use the detour the best thing to do is to allow plenty of extra time and bring extra water and snacks for the car.
A fish passage barrier is anything that hinders fish from moving upstream or downstream.

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.
Metal pipe 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 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.
The following fish species are found in the Tuck Creek Basin:
  • Chinook Salmon
  • Coho Salmon
  • Chum Salmon
  • Pink Salmon
  • Steelhead Trout
  • Cutthroat Trout
A fishway is a human-made concrete structure that helps provide easier access to migrating fish in a river or stream. The one we are removing has six ascending pools separated by concrete walls with an opening down the middle. The pools provide a place for fish to rest as they continue to swim against the current. The walls act to slow the rushing water that is forced out of the existing narrow pipe culvert. Once the narrow pipe is replaced with a wider concrete box culvert, there won’t be a need to slow the water down because the water will flow through like a natural stream. We are removing the existing fishway and replacing it with natural creek habitat.
The previous metal pipe culvert was wide enough to prevent the road from flooding. However, it was rusted and old and needed to be replaced before it collapsed. If the pipe collapsed, and there was no place for the water to drain other than the onto the roadway, then the force and volume of the water could have caused the entire roadway to break apart and sink.
The previous metal pipe would have failed if not replaced. The county replaced it with a larger box culvert so that fish have a much easier time passing underneath the road. This is part of the county’s Fish Passage Restoration Program.
The previous 30-year-old metal pipe culvert is 96 inches (8-feet) in diameter and 50 feet long.
The new box culvert is 22-feet-wide, 10-feet high and 98-feet long.

Photos

Excavators dig out the old, failing culvert.

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.

 

Crews roll over the smooth surface of the freshly paved section of NE Woodinville Duvall Road above the new concrete box culvert.

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. 

 

Trees and rocks fill the downstream section of Tuck Creek leading to the new 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.

 

New box culvert shows the safety guardrail with the creek flowing freely below it.

Aug. 23, 2023 – A view from above the new box culvert shows the safety guardrail with the creek flowing freely below it. 

 

Culvert concrete is carefully poured between wall sections of the new culvert to secure them in place and prevent leaks.

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. 

 

The walls and floor of the new box culvert are in place.

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. 

 

An excavator works to ready the new stream bed between the retaining walls on either side of the new box culvert.

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)

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