Kitsap County’s Washington Boulevard Landslide Stabilization Project Honored at AWPA’s Spring Conference

Aspect joined staff from Kitsap County Public Works (County) at the American Public Works Association (APWA) Spring Conference in Tacoma to celebrate the County’s Washington Boulevard Landslide Stabilization project, which earned the APWA’s 2022 Public Works Project of the Year award in the Disaster or Emergency Construction Repair (less than $5 million) category.

Members of the Washington Boulevard Stabilization team accepting their award (from left to right): Andrew Nelson, Kitsap Public Works Director; Tina Nelson, Kitsap Senior Program Manager; Joe Rutan, Kitsap County Engineer; Tim Beachy, Kitsap Project Manager; David Dinkuhn, Parametrix Civil Engineer; Andrew Holmson, Aspect Consulting; Steve Nichols, Kitsap Construction Manager; Tom Abplanalp, Sound Pacific Construction; Phil Struck, Struck Environmental; Paije Abplanalp, Sound Pacific Construction.

Washington Boulevard traverses a steep coastal bluff along the eastern Puget Sound shoreline in Kingston, Washington, leading into the town center and regional ferry terminal. Part of the road crosses a large deep-seated landslide complex that for decades suffered failures after heavy rains, frequently cutting off the sole access to the town and emergency services for 22 homes along the road. The Washington Boulevard Landslide Stabilization project constructed a horizontal drain system, stormwater improvements, and mechanically stabilized earth (MSE) slope to stabilize the roadway and provide a reliable path to the town and services for residents.

Roadway damaged after slope movement in 2011.

Temporary roadway protection measures in place.

In the winter of 2006, a period of extreme rainfall triggered significant landslide movement and damage to the roadway. Kitsap County engaged Aspect to complete detailed geologic investigations to characterize the nature of the landslide, conduct emergency monitoring, help the County decision-makers understand the risks the landslide posed to the roadway, and to develop viable stabilization alternatives. After over a decade of active monitoring and management, the increasingly frequent road closures and need for repairs due to landslide movement prompted County decision-makers to start design and construction of the preferred stabilization alternative.

Horizontal Drain Drilling (HDD) near the steep bluff.

Aspect led design of the horizontal drain system to dewater the body of the landslide, roadway stormwater improvements to enhance collection and conveyance of stormwater on/near the roadway, and a mechanically stabilized earth (MSE) slope to achieve grade transitions at the landslide headscarp and support the roadway embankment. This solution struck an elegant balance between effective stabilization targeting the root cause of instability (elevated groundwater), an environmentally permittable, sustainable, and beneficial design, and cost.

Roadside Drainage Improvements and Roadway Base Preparation.

Final paving of road reconstruction with guardrail.

Aspect and the County worked in close collaboration with Parametrix for civil design and Struck Environmental for environmental permitting to deliver a pragmatic design meeting the project objectives, schedule, and budget. The project was successfully constructed by Sound Pacific Construction with key support from Jensen Drilling, Inc.

Senior Associate Geotechnical Engineer Andrew Holmson, PE, who has worked on the project since 2008 alongside over a dozen Aspect geologists and engineers, joined Tim Beachy, Tina Nelson, Andrew Nelson, and Joe Rutan from Kitsap County; David Dinkuhn from Parametrix; Phil Struck from Struck Environmental; and Tom and Paije Abplanalp from Sound Pacific Construction for the awards ceremony.

The full list of this year’s APWA Washington Project of the Year winners and project photos are available on their website.

Jamestown S’Klallam Tribe’s Rivers Edge Levee Setback Project Wins ASCE LOCEA Award

The Seattle Section of the American Society of Civil Engineers (ASCE) honored the Jamestown S’Klallam Tribe’s (JST) Rivers Edge Levee Setback project with its 2022 Local Outstanding Civil Engineering Achievement Award (LOCEA) in the Geotechnical category.

The project replaced an aging, constricting levee on the Lower Dungeness River near Sequim with a new levee setback designed to meet modern flood protection standards and aligned to restore the area’s natural floodplain and salmon habitat. Work completed on a compressed, whirlwind schedule. JST acquired the land and started preliminary design in mid-2020, and by September 2021, they’d completed final design, successful navigation of a complex series of permit applications and design reviews, and substantial construction—a monumental feat in just 14 months.

The new levee was constructed in part with gravel from a nearby quarry pit, limiting the cost, time, and environmental impact of importing materials to the site. The project was done in tandem with an adjacent similar levee project by Clallam County, and together they will open up 143 acres of reclaimed floodplain and habitat. You can learn more about the Rivers Edge project in our previous blog post.

Aspect led geotechnical engineering design and construction of the levee as a subconsultant to Pat McCullough and his firm Engineering Services Association (ESA), alongside WEST Consultants for hydrology and hydraulics.

Aspect’s Project Manager and Lead Geotechnical Engineer Andrew Holmson and Project Geotechnical Engineer Mari Otto gave a short presentation on the project during the LOCEA virtual awards ceremony on Wednesday, March 9.  

Other LOCEA Winning Projects

Aspect was also on the winning teams for two projects as geotechnical subconsultants to our frequent teaming partner Osborn Consulting:

  • The City of Kenmore’s new boathouse on the Sammamish River won in the Small Projects and Non-Construction Studies category. We provided foundation redesign support and services during construction of the two-story prefab metal building that is the new home for the Kenmore Community Rowing Club and Northshore School District rowing programs.

  • The City of Sammamish’s Ebright Creek Fish Passage Culvert Replacement was honored in the Water Resources category. Aspect led the geotechnical evaluation for design and construction of two new 30-inch-diameter culverts along busy arterial East Lake Sammamish Parkway. Replacing the outdated culvert was a priority for the City of Sammamish to enhance fish passage and habitat for kokanee salmon. Construction was completed in fall 2021, and the City has already seen an increase in returning kokanee and other fish species passing through this stretch of the creek.

This year’s other LOCEA winners honored during the ceremony were:

  • Climate Pledge Arena Renovation (Thornton Tomasetti) – Structures

  • Northgate Link Extension (MJA) – Transportation and Development

  • 2021 Airfield Pavement Replacement + Infrastructure Upgrade Project (HNTB) – Transportation and Development

  • Seattle-Tacoma International Airport North Satellite Modernization (AECOM) – Transportation and Development

20+ Years in the Making: Levee Sparks Dungeness River Restoration

On the Olympic Peninsula in Northwest Washington, the Lower Dungeness River Floodplain Restoration project restores habitat and natural river processes that are confined by various levees and dikes constructed in the 1940s through 1960s. The lower reaches of the Dungeness River have been constricted on the right bank by an existing 2.4-mile-long levee built in the 1960s by the United States Army Corps of Engineers (USACE). However, the USACE levee is ‘under-designed’ for anticipated flood events to come.

Aerial view of the 2,600-foot setback levee

Photo credit: Jamestown S’Klallam Tribe (JST)

Twenty years ago, the Lower Dungeness River Floodplain Restoration project was conceived with the goal of building a new setback levee and reconnecting the Dungeness River with its historical floodplain; improving habitat conditions; and restoring riverine processes and functions. The project was split into two parts: the Clallam County (County) levee setback project from River Mile (RM) 0.8 to 1.75, and the River’s Edge Project between RM 1.75 to 2.7. The County project started in 2015, but then the floodplain restoration work hit a standstill – until the Jamestown S’Klallam Tribe (JST) brought the River’s Edge Levee Setback project to life.

Jamestown S’Klallam Tribe Rebuilds a Floodplain to Restore the Region

For thousands of years pre-colonialism, the JST nurtured the land and many saltwater bays and freshwater rivers. Today, the JST takes an active role in community environmental projects, including participating in the Dungeness River Management Team and implementing habitat restoration projects such as this levee project, which is a part of the Lower Dungeness River restoration efforts.

JST purchased farmland along this stretch of the Dungeness River (with a strong show of support from local community members) with the understanding that the purchased land would be used for conservation efforts. JST secured funding support from Washington state’s  Floodplains by Design grant and brought on Engineering Services Association (ESA) to lead the project design. ESA in turn brought Aspect in to be the geotechnical lead, as well as several other key team members like WEST Consultants (hydrology and hydraulics) and Johnston Land Surveying.

The River’s Edge project will renew historical riparian habitat and boost the overall health of the ecosystem, including salmon recovery for key species like Chinook salmon, summer chum, bull trout, and steelhead. The new setback levee will also double as a walking path to be used by all members of the community.

Early Detective Work in a Floodplain Leads to Success

Rivers deposit soils in highly varied and complex ways. To set up the 2600-foot-long setback levee for success and understand the subsurface conditions, Aspect led a two-phase subsurface exploration program that included six soil borings (2 with vibrating wire piezometer installations), 11 test pit excavations, 13 hand-dug explorations, and 4 cone penetrometer explorations. Using this information we created a profile of subsurface conditions to power smart levee design.

Levees Need to Be Made of the ‘Right Stuff’

Nearby gravel pit that ‘fed’ the levee

Photo credit: Krazan & Associates

A key driver in any levee project is the availability of material. This levee was made up of over 37,000 cubic yards of gravel and sand. ESA identified a material source only two minutes away and Aspect and ESA tailored the levee design to make sure the material available from the gravel pit could be successfully used to build the levee to meet design standards. Having a material source so close to the Site helped save budget, time, and greenhouse gas emissions.

Finishing a 2,600-Foot Levee in Under Two Years: A Win !

Floodplain restoration without River's Edge Levee Setback project (on the left) and WITH River's Edge Levee Setback Project (on the right).

Photo credit: North Olympic Land Trust

Aspect collaborated with ESA, JST, and USACE to design the setback levee in just under one year, with construction of the project hot on the heels of the final design submittals. Construction then started and the new setback levee was built in just over 2 months!

In summer 2022, the existing levee will be removed to allow the Dungeness River to reclaim 56 acres of floodplain. The Clallam County project will eventually tie into the River’s Edge Setback Levee to open up an additional 87 acres for a combined 143 acres of reclaimed historical floodplain and habitat for salmon, birds, and wildlife.

The hard work and dedication of the River’s Edge project team helped realize the JST’s desire to create a quality setback levee that meets the latest and greatest safety standards, within their desired schedule – and underbudget!

Helping Power Seattle's Tech Sector

Seattle City Light is about to unveil its new state-of-the-art substation that will transition this South Lake Union site from a Greyhound bus maintenance facility and parking lot into an “architectural marvel.” From property acquisition and contaminant remediation through design and construction, Aspect completed a full range of environmental and geotechnical services to support the redevelopment of a sleek electrical substation wedged in the heart of Seattle’s tech sector.

Check out this great Seattle Times article on the new substation and peruse some photos of the truly impressive facility.

Reigning in the Looming Landslide in Kitsap County

As the Washington Boulevard landslide continues to move, it threatens to cut numerous Kingston residents off from the town and emergency responders.

Since a significant slide in 2006, Aspect has provided geotechnical services at Washington Boulevard, including gathering data and monitoring and studying movement along the slope. Recently, Kitsap County Public Works decided to implement a slope dewatering system to remove groundwater from the landslide mass and increase the stability of the hillside and roadway.

Aspect’s Andy Holmson provides some insight to the solution in this Kitsap Daily News article.

Aspect's Andrew Holmson Presenting at APWA's Fall Conference

Aspect’s Andrew Holmson will be presenting at the American Public Works Association’s (APWA) fall conference in Spokane on Thursday, October 6. He and City of Port Angeles Engineering Manager Kathryn Neal will present Protect and Innovate: Port Angeles Landfill Stabilization – the story of how the City and a large, multidisciplinary team relocated 400,000 cubic yards of refuse away from a 140-foot bluff overlooking the Strait of Juan de Fuca while building Washington’s tallest reinforced soil slope.

Aspect has provided geotechnical engineering, hydrogeology, and environmental support to the City’s closed landfill facility since 2007. We led the engineering geology team in determining long-term and short-term shoreline and bluff retreat rates, evaluating options for removal of existing shoreline protection structures, extending or modifying the structures, evaluating bluff slope failure mechanisms and slope stabilization options, landfill cell relocation, and fill slope stabilization and design. Work on the slope was completed ealier this year. Aspect continues to support the City with operation and maintenance of the landfill gas system and have provided environmental monitoring and support to meet regulatory reporting requirements.

Learn more about the APWA’s fall conference here and read more on Aspect’s efforts on the landfill here.