Let the construction marathon begin.
Those who drive on state Route 169 through Black Diamond are familiar with construction along the road at this point — but a roundabout project, which has taken the city seven years to plan, will take the cake.
At least, until the state steps in with their own water culvert project right after.
But first things first. In a nutshell, the city will be building two roundabouts on SR 169, with an estimated completion around February 2026.
The good news, though, is that that construction has been planned to disrupt traffic as little as possible, at least for regular commuters and people who patron businesses north of town.
The project is paid for by Oakpointe, the Ten Trails developer, as part of a master plan agreement that stipulates the developer build various road improvements when the neighborhood hits certain population numbers.
There will be numerous updates over the next two years about traffic on SR 169 — alerts will be posted on the city’s Facebook and Instagram pages, plus the Black Diamond Police Department Facebook page.
PROJECT DESIGN AND TRAFFIC IMPACTS
This project, as the two-and-a-half-year timeline suggests, has many phases, and each affect traffic in different ways. However, most phases shouldn’t cause any travel delays, and none completely close the highway, said Black Diamond’s Master Development Review Team (MDRT) Director Andy Williamson.
Access to local businesses will not be limited, he added.
However, Roberts Drive will be closed for one of the earlier phases of the project.
Below are the general phases of the work for readers; they are not the official phases presented by the MDRT, and could be adjusted in the future.
Once complete, there will be two one-lane roundabouts (though they will be built to be able to expand to two-lane roundabouts if necessary).
The first will be located at the SR 169 and Roberts Drive intersection; the second at the Pipeline Road intersection.
Additionally, the Black Diamond-Ravensdale Road intersection will become right-in, right-out. This means drivers going south need to use the Roberts Drive roundabout to access the road.
Similarly, drivers coming off Black Diamond-Ravensdale Road wanting to go south will have to use the Pipeline Road roundabout to do so. For more information on this, read on.
Finally, sidewalks will be constructed to make the west side of SR 169 more accessible.
Phase 1
Phase 1 of the the roundabout project is, if driving into Black Diamond from the north, is affecting the northwest corner intersection of SR 169 and Roberts Drive.
This part of the project, which is removing the stormwater pond and creating an underground stormwater “vault” to treat stormwater and runoff, began Sept. 15.
Drivers going south might have noticed that the right-hand turn onto Roberts Drive has changed because of this construction, but does not affect the flow of traffic.
The vault is expected to be completed around February 2024.
After the roundabout project is completed, Black Diamond hopes to build a park on top of the vault.
Phase 2 & 3
The next two phases will build out the first roundabout at Roberts Drive; this is the only time Roberts Drive is expected to be closed to traffic, and drivers are advised to use Baker Street; truck drivers are to use 288th.
It’s unclear at this time when Roberts Drive will be closed, as work on the west and east halves of the roundabout alternate between March 2024 and February 2025.
Traffic going north and south on SR 169 will be able to drive right past the construction, though lanes might be shifted depending on which half of the roundabout is being worked on.
Phase 4
Phase 4 is construction on SR 169 between the two roundabouts, as well as south of the Roberts Drive roundabout.
This will affect commutes, as construction will bring the highway down to one lane. However, Williamson said the city is working with their contractors to limit lane reductions to after high-traffic times.
“We’re trying to be thoughtful of the commuters,” Williamson said. “We don’t know exactly what hours yet… but our peak commute around 6 p.m., so we’ll do something after.”
It’s unclear at this time when drivers can expect lane reductions.
Phase 5 & 6
Construction east and west halves of the Pipeline Road roundabout begin in Phase 5 and 6.
Like previous phases involving roundabouts, traffic on SR 169, as well as access to businesses, will remain unimpeded.
These phases are planned for February 2025 through November 2025.
Additionally, once this roundabout is completed, Black Diamond-Ravensdale Road will become a right-right only only street.
Why is this road right-in, right-out only?
The plan to make Black Diamond-Ravensdale Road right-in, right-out only caught a few people by surprise, according to social media comments.
According to Williamson, this decision allows for a better flow of traffic coming off the road.
“This lets you continue to move,” he said, adding that this is a design required by the state.
Then why not make the second roundabout at Black Diamond-Ravensdale Road?
Williamson said that below SR 169 and Black Diamond-Ravensdale Road is a couple of large fish culverts that prevent a roundabout from being built at this intersection.
Additionally, those fish culverts are expected to be upgraded by the state after this roundabout project is completed.
WSDOT FISH CULVERT PROJECT
After the two roundabouts are completed, the state is stepping in for another five-year project constructing culverts underneath the highway in two places and Black Diamond-Ravensdale Road, starting in 2024.
Because of Black Diamond’s roundabout project, WSDOT’s work on fish culverts will start at Jones Lake, which is the body of water located to the west just outside the city’s southern limits.
Under the highway are three streams, one call Rock Creek (the other two are unnamed).
Once the roundabout project is completed, WSDOT will tackle the Grinder Creek and another tributary under Black Diamond-Ravensdale Road and SR 169. One of these culverts is fully considered impassible to the coho, and the other is rated as only 33% passable. Expanding these culverts trout, steelhead, and sea run cutthroats that use these creeks
At this time, it is unclear if the construction of these culverts will affect traffic on SR 169 or Black Diamond-Ravensdale Road.
“This is a design-build project. As part of this process, one of our primary goals is to develop effective design and construction methods, traffic control and staging strategies that will minimize impacts to traffic, local communities, businesses, property owners and utilities,” said WSDOT Communications officer Krista Carlson. “More information about travel impacts will be available as we get closer to the start of construction.”
WSDOT is being required by the federal government to repair fish culverts across the state because a 2013 U.S. District Court order, after 21 Washington state tribes sued the state for failing to protect their treaty-based duty to preserve fish runs.
Over the next two and a half years, SR 169 will see crews constructing two roundabouts in SR 169, one on Roberts Drive and the other on Pipeline Road. Currently, work is being done in the large green patch near Roberts Drive creating a water treatment “vault”, which will be underground. Image courtesy city of Black Diamond Over the next two and a half years, SR 169 will see crews constructing two roundabouts in SR 169, one on Roberts Drive and the other on Pipeline Road. Currently, work is being done in the large green patch near Roberts Drive creating a water treatment “vault”, which will be underground. Image courtesy city of Black Diamond
