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Coal Creek Bridge No. 3035A located southeast of Black Diamond in unincorporated King County.

Status update

Monday, August 2, 2021

We successfully finalized a project contract with our contractor in July 2021. We are now working with our construction contractor to determine a revised start date and schedule for the project. At this point, there is a possibility we won’t be able to start work this summer. More information will be available later this month.

Learn what to expect during construction: We held an online community meeting about the project on June 22. See a recording of the live meeting presentation on Facebook . Here is a copy of the PowerPoint presentation PDF 5MB. For additional information, or to get a copy of the presentation in another format, please email .



Project overview

King County plans to begin work to remove and replace the Coal Creek Bridge on SE Lake Walker Road this summer. The 63-year-old timber support structure is decaying, the 108-year-old steel floor beams are rusted, the paint is peeling, and the bridge has weight restrictions for heavy trucks. The new bridge structure will be open to all vehicles, carry no weight restrictions, and is expected to last for decades.

Getting through the construction zone

King County will build a temporary one-lane bridge to carry traffic over Coal Creek just downstream of the current bridge. There will be no weight restrictions on the temporary bridge. When the temporary bridge is open to traffic, workers will close and remove the existing bridge. Travelers will always have local access in both directions over Coal Creek.

Construction timeline

  • Pre-construction utility relocation: June/July 2021
  • Equipment on site: Summer 2021 - Spring 2022
  • Temporary bridge opens: August 2021
  • Construction complete (anticipated): Spring 2022

Bridge history

  • Built in 1958 with timber creosote substructure
  • Used recycled superstructure from a different bridge
  • Is sole access bridge - serves single family and mobile homes
  • Is two-lane single span bridge, 41 feet long and 18 feet wide
  • Has 310 vehicles per day including about 5 trucks per day

On this page

Public outreach

June 22, 2021 – Virtual community meeting:
- Live recording on Facebook
- PowerPoint presentation slides PDF 5MB

June 1, 2021 - Flyer PDF 211KB

July 15, 2020 - Flyer PDF 631KB

March 26, 2019 - Open house materials:
Display boards PDF 11MB
Handout PDF 469KB
Comments summary PDF 4MB

March 7, 2019 - Flyer PDF 86KB

Contact us

Broch Bender, Communications Program Manager
Desk: 206-263-1189

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Why King County is replacing this bridge

Losing steel.
We are losing sections of steel.
Severely rusting.
The super-structure is 108 years old and severely rusting.
Timber issues.
The 63-year-old creosote timbers are rotting.
Paint issues.
Paint peeling.

Frequently asked questions

The existing bridge is deteriorating and needs to be replaced. The 63-year-old timber support structure is decaying, the 108-year-old steel floor beams are severely rusting, the paint is peeling, and the curve in the road and bridge do not provide adequate visibility to oncoming traffic.

The bridge has been categorized as structurally deficient and functionally obsolete.

Structurally deficient means there are significant load carrying elements of the bridge that are in poor condition due to deterioration and/or damage or the waterway opening provided by the bridge is insufficient causing water overtopping with significant traffic delays. The fact that a bridge is “structurally deficient” does not imply that it is likely to collapse or that it is unsafe. It means that the bridge must be frequently monitored, inspected and maintained.

A functionally obsolete bridge is one that was built to standards that are not used today. Functionally obsolete bridges are those that do not have adequate load carrying capacity, lane widths, shoulder widths, approach roadway alignment, horizontal and vertical clearances to serve current traffic demand, or those that may be occasionally flooded.

Yes. The Road Services Division bridge inspection team has inspected the bridge every 6 months since 2017 to ensure the bridge is safe for vehicular traffic under current weight restrictions. This is more frequent than the required 24-month inspection cycle. If repairs are needed due to findings during the inspections, the inspection team works with our maintenance staff to perform the work to keep the bridge safe for public use until the bridge is replaced.

Yes, there are. The current weight limits for single unit vehicles are:

4 Axles – 26 tons
5 Axles – 30 tons
6 Axles – 32 tons
7 Axles – 35 tons
Noise levels will be typical for high- impact construction, including excavation, jack hammering, and saw-cutting.
Construction crews will typically work Monday through Friday during the day but there may be occasional weekend and/or nightwork.
Construction barriers will surround the construction area to contain construction-related materials from polluting the water. Also, the creek will be routed through a temporary bypass pipe to further protect fish and wildlife.
The projected bridge replacement cost is $4.7 million.

Project documents

Contact us

24/7 Road Helpline: 206-477-8100 or 1-800-527-6237

TTY Relay: 711

Twitter: @KCRoads