Ship Canal Water Quality project update 11/23/20

City of Seattle, Washington sent this bulletin at 11/23/2020 04:28 PM PST

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Secant pile wall construction in Fremont

Dear neighbors,
Happy Thanksgiving! This whole year has been transformed as we continue to follow critical public health guidance in our workplace and communities. Working or schooling from home, especially next to a busy construction site, is extra challenging. We are thankful for your patience and support as we continue this essential work to reduce combined sewer overflows in our waterways by 2025.

Secant pile wall construction for the drop shafts is underway in Fremont and Queen Anne and will begin in Wallingford soon. This work is, unfortunately, noisy. We start early in the morning to allow the contractor to complete more of the work during daylight hours to improve safety, to maximize the use of expensive, heavy machinery each day and, to complete work as efficiently and cost-effectively as possible. To learn more about how, and why, secant pile walls are constructed, check out this video that was produced as part of a separate King County Wastewater Treatment Division combined sewer overflow control project.

While construction activities and related noise will persist at each site after the secant pile walls are complete, we do expect the remaining construction activities to be less impactful.

The contractor will not work Nov. 26 - 29. We wish you a safe and restful holiday.

Ballard

Completed shaft excavation in Ballard

Shaft excavation is complete! We've excavated down about 122 feet and will begin constructing the permanent shaft floor and installing wall liners. This work is anticipated to last through early January. During this time, you can expect:

Trucks coming in and out of the site to deliver equipment.
Intermittent days of large concrete pours. On these days there will be many trucks delivering concrete to the site, back to back. Work on these pour days may occur well beyond regular working hours due to the amount of concrete that needs to be placed (the shaft floor is 14-ft thick and 87-ft wide). We anticipate our first large pour to take place in mid-December.

Working hours are expected to be 7 am - 5 pm Monday through Friday. Night and weekend work may occur on concrete pour days.

East Ballard

Soil stabilization continues. Through late January, you should anticipate:

NW 45th St closed to traffic; vehicles must detour onto NW 46th St.
11th Ave NW will remain open now through Dec. 31 to lessen impacts to holiday traffic in the area.
Burke-Gilman Trail users remain detoured to the north side of NW 45th St; flaggers to help direct traffic during daytime working hours. Please follow all detour guidance on site. Bicyclists must cross train tracks at 90-degree angles. Please use extra caution in wet weather as ramps may be slippery.

Regular work hours will be Monday through Friday, 7 am to 5 pm. Night and weekend work may occur to maintain progress.

See anticipated traffic impacts through 2022 on our website.

Fremont

Secant pile wall construction continues until late December. So far we've installed about half of the 46 total piles. For the next several weeks, you should anticipate:

Heavy equipment on site such as the drill rig, an oscillator, and a crane.
Trucks coming in and out of the site to haul away excavated material and deliver concrete.
Noise and vibration from the drill rig. You may be able to feel the vibration which is expected. We are monitoring vibration levels on site to ensure they are within allowable levels.
NW 36th St between Leary Way NW and 3rd Ave NW closed (through remainder of the project).
Pedestrians detoured to the north side of Leary Way NW.
A pump and bypass system running 24/7 to re-route an existing drainage line around the secant pile construction. This system is powered by a generator and will be in place through the end of the year.

Regular work hours will be Monday through Friday, 7 am to 5 pm. However, the contractor anticipates working on Saturdays through mid-December, 9 am to 5 pm, to maintain progress.

Wallingford

Crews will install a dewatering discharge pipe in N 35th St between Interlake Ave N and Stone Way N and prepare for secant pile wall construction over the next few weeks.

This week, our contractor will saw-cut the pavement along the northern edge of N 35^th St to prepare the work area. After Thanksgiving, they will re-mobilize and begin the trenching and pipe installation work.
The contractor will have flaggers on site to manage traffic flow. There will be limited lane closures along N 35th St and on Stone Way N in areas where the crew is working and a short-term closure at the south end of Interlake Ave N when crews trench across this intersection.

Most of the work is planned Monday through Friday between 7 am and 5 pm. The work in Stone Way N will occur over a weekend and is currently planned for Dec. 4-6.

Queen Anne

Secant pile wall is underway and is anticipated to last through mid-December. So far we've installed about one-third of the 36 total piles. During this time, you should anticipate:

Heavy equipment on site such as the drill rig, an oscillator, and a crane.
Trucks coming in and out of the site to haul away excavated material and deliver concrete.
Noise and vibration from the drill rig. You may be able to feel the vibration which is expected. We are monitoring vibration levels on site to ensure they are within allowable levels.
The West Ewing Mini Park parking lot closed. This closure is anticipated to last through mid-2023.
A localized Ship Canal Trail detour through summer 2022 (see map).