35th Avenue SE Reconstruction

It Is Finished!
Final video of the 35th Avenue SE Reconstruction Project, which was completed on March 11, 2019.

Latest News ~ March 11, 2019

An image of the completed roadwayAfter years of flooding and eight months of construction, construction on 35th Avenue SE in Mill Creek is complete and the roadway is reopened to traffic and pedestrians.

The project raised the roadway several feet above the prior road elevation over Penny Creek to eliminate flooding, which occasionally closed the roadway over the last several years. Work included driving 505 pin-piles up to 37 feet deep through peat into good load-bearing soil, constructing a concrete slab on top of the pilings, and then reconstructing and elevating the roadway on top of lightweight concrete fill. New sidewalks were poured for pedestrian access, and landscaping was restored.

Crews also removed two 54-inch culverts to restore fish passage to the area, which will also improve the health of the waterway.

This is the largest road construction project in Mill Creek’s history.

Feb. 28, 2019
Construction on 35th Avenue SE through Mill Creek ceased in early February due to snow/ice and freezing temperatures. However, work is again underway. Concrete work is in process with the goal of wrapping up at the end of this week.

The asphalt work is the last major hurdle. To lay asphalt, the ground temperature needs to be at least 35 degrees. In cold weather, the ground temperature can be up to 8 degrees cooler than air temperature. Following asphalt application, permanent road marking will be completed. As long as ground temperature cooperates, the City’s goal is to reopen the road by March 15. The City is doing everything it can to drive toward that date.

We are excited to be in this final stretch! Thank you for your patience throughout this lengthy project!

Jan. 11, 2019
Thank you for your patience as construction continues on the 35th Avenue SE Reconstruction project in Mill Creek. We are making great progress.

The bridge deck is being poured. The material used is cellular concrete fill, which is a carefully crafted mix of cement, water and pre-formed foam that functions as light-weight concrete. It looks like a slurry mixture. There is a cellular concrete plant at the site. It is a tall yellow silo, which observers of the project site can see from outside the construction zone. It holds the cement, while the gray and white storage tanks hold additional cement. The eight-month project timeline still has the roadway scheduled to reopen in March, depending on weather.

Thank you for being respectful of those living in neighborhoods adjacent to 35th Avenue and taking alternate routes when traveling through the City. We just have a few more weeks of this inconvenience, and we appreciate your support for the duration of this project.

We are eager for the work to be completed and the roadway to be open, and look forward to celebrating with our community when we achieve that milestone.

An image of the 35th Ave reconstruction bridge deck in Jan 2018

An image of the 35th ave project bridge deck with cellular concrete fill

An image of the on-site concrete plan for the 35th Ave project

The project site as of Jan. 8, 2019

Update for Nov. 16, 2018

An overhead view of the project siteThe City of Mill Creek’s 35th Avenue SE reconstruction project has achieved several significant milestones.

As of Nov. 14, all 505 pin piles are installed. The pile-driving work began in August and took several months to complete as the six-inch diameter pin piles were driven through a large peat deposit to load-bearing ground. The average depth was 37 feet below ground. The bridge and roadway on either side of the bridge will be supported by the pin piles.

Crews also removed two 54-inch culverts to restore fish passage to the area, which was a change order to the original project. Thomas Lake is immediately to the east of the roadway, and Penny Creek is a fish bearing stream that crosses underneath the roadway. All fish-blocking culverts in the state must be removed by 2030. Shortly after project approval, the City received the permits to remove the culverts. The ability to complete the culvert removal in 2018 means that the City would not need to reclose the roadway in future years to comply with this federal regulation.

The bridge abutments are built and bridge concrete work is underway. Other work on the project site includes rebuilding concrete sidewalks with curbs and gutters, landscaping, and installing fencing and signs.

The project  is slated to open in March 2019, depending on weather. The original project timeline cited eight months to complete the work. While there was anticipation that the road might be able to open earlier, the items noted above means that the work remains on the original eight-month schedule.

View aerial footage of the construction site: https://youtu.be/6vusklbLMoY.

The construction sign has been placed at the project site Overview
35th Avenue SE is a three-lane minor arterial in Mill Creek that carries approximately 15,000 vehicles per day. The road was widened by Snohomish County in 2003 by using lightweight fill on top of a large peat deposit. The road has been continually settling since annexation by the City in 2005.

The rate of settlement has slowed, but portions of the road have settled over two inches in the past three years and two feet over the past 10 years.

Project location informationOne of the biggest areas of settlement is over the Penny Creek crossing between 144th Street SE and 141st Street SE, which also has the deepest deposit of peat material as a base. The water level in the surrounding wetlands has also increased due to several factors such as upstream development and downstream beaver activity. The rising water combined with a sinking roadway has resulted in several road closures over the past few years due to flooding.

Reconstruction Project
The reconstruction project will fix the road between 141st Street SE and 144th Street SE to eliminate flooding and associated road closures.

Work includes driving approximately 500 pin-piles through the peat into good bearing soil, constructing a concrete slab on top of the pilings, and then reconstructing and elevating the roadway on top of lightweight concrete fill. The project will raise the road elevation up to four feet above the existing roadway elevation.

In addition, the work includes treating stormwater from the roadway, which currently flows directly into the adjacent wetland without any treatment. Water quality and the method of distribution into the surrounding wetlands will be improved. Fish and wildlife will indirectly benefit from the improved water quality resulting from stormwater runoff treatment.

The width and alignment of the roadway will not change.

Reconstruction began on June 18, 2018 . The construction is slated to be substantially complete and open to the public in March 2019.

Construction may occur between 7 a.m. and 9 p.m. Monday through Friday, or between 8 a.m. and 9 p.m. on weekends. Equipment is anticipated to run during normal working hours of 7 a.m. to 7 p.m. Monday through Friday for the majority of the project.

Detour Route
Traffic that normally utilizes 35th Avenue SE in Mill Creek is detoured via 132nd Street SE and SR 527 (the Bothell-Everett Hwy). The City strongly discourages the use of side roads off 35th Avenue SE for unofficial detour routes, as these are residential neighborhoods not built for arterial traffic. The side roads should only be used by local access vehicles. Local access means you live in one of the neighborhoods adjacent to 35th Avenue SE, including Highland Trails, North Pointe, Silver Crest, Silver Glen and Webster's Pond.

The total cost is estimated at approximately $5,303,300. The State Department of Transportation office has included a $5.25 million funding package for this project by the City of Mill Creek. Snohomish County also provided a $50,000 small capital projects partnership grant.

Environmental Impacts
The project requires work over Penny Creek, where it crosses beneath the 35th Avenue SE roadway and in the adjacent wetlands on the west side of the roadway and the east side of 35th Ave SE.

Raising the height of the roadway will require alteration of the existing stormwater discharge points into the adjacent wetland. The replacement storm drain lines will be placed a short distance into the wetland. A minimal amount wetland vegetation will be damaged or removed during excavation of the trenches to place the storm drain lines.

After the trenches have been backfilled and native soil placed where feasible, exposed soils and disturbed areas will be treated with native seed mix and willow stakes.

Groundwater encountered during construction will be discharged to an upland area or pumped into an above-ground tank and treated to meet state water quality standards.

There will be no discharge of waste materials to surface waters.

Frequently Asked Questions
Download and print a copy of the FAQs

Why are there no plans to widen the roadway to two lanes in each direction?
The roadway will not be expanded due to the associated environmental impacts to the surrounding wetlands and stream crossing. The peat bog surrounding 35th Avenue SE is a unique environmental asset, and is part of a large wetland and stream complex that provides wildlife habitat and flood mitigation. Thomas Lake is immediately to the east, and Penny Creek is a fish bearing stream that crosses underneath the roadway. Mosses in the peat can absorb and “lock up” excess carbon dioxide in the atmosphere, which can help mitigate global climate change since the acidic conditions in the bog results in slow organic decay.

Why is this project occurring in 2018 when other projects are happening?
The project timing is driven by two things: funding and functionality. The City is receiving a significant amount of funding from the state for this project. Some funds became available in 2017-2019, and all the funds must be used by 2019. Even though most of the work is occurring in 2018, some work needs to take place in 2019. By delaying a year, it could jeopardize the funds for project work running into 2020. Even if the City had waited until 2019, construction would still be occurring on the County’s 35th Avenue project and on the Swift Green Line project. In addition, by waiting, the City’s project costs would likely increase.

The functionality of the road also is an impetus for completing the project. Each year, the City currently is closing the road or diverting traffic into the center turn lane for extended periods of time due to water over the roadway. As part of the City’s commitment to preserving its infrastructure, timeliness is of the essence when scheduling this project.

Will this really fix the road? Will there be more flooding in the future?
The reconstructed roadway will be raised above the existing elevation. While flooding will no longer occur, since the roadway is a non-permeable surface, water may puddle during rain. However, following reconstruction, the roadway should not be closed due to impacts from water.

Will the road be closed to traffic?
Yes, the road is fully closed to traffic. Traffic cannot to get by on 35th Avenue SE between 139th Street SE and 144th Street SE.

What is Mill Creek doing to mitigate traffic impacts in local neighborhoods?
The City has provided signage to inform people of the road closure at key points along the roadway outside and inside Mill Creek city limits. Electronic and static signage are posted with detour routes. In addition, signage is posted at the entrances to the Highland Trails, North Pointe, Silver Crest and Silver Glen neighborhoods that states “local access only” and “no outlet.” To help slow traffic down in the neighborhoods, temporary speed bumps are installed. Digital speed feedback signs are posted, and police will have presence throughout the neighborhoods and at stop signs to ensure drivers are behaving appropriately.

Why wasn’t there coordination about entities to ensure construction project timelines didn’t overlap?
The City coordinated with several other entities, including Washington Department of Transportation, Snohomish County, Community Transit, Puget Sound Energy, Snohomish County PUD, and the City of Everett. Because each entity has its own Capital Improvement Plan, projects will inevitably overlap at times. The City’s coordination effort with these other entities ensured that full road closures will not overlap and that one project’s detour route is not compromised by another project.

What are the implications of state funding for this project?
The state’s prioritization of funding for the 35th Avenue SE reconstruction project is a positive thing. In fact, state and federal funding is pouring into Snohomish County for many entities due to the tremendous growth in the area. This investment in growth management is positive for the area.

Historical Background Information
An MDNS was issued for the 35th Avenue SE reconstruction on September 23, 2015:

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