11.02.2020  |  Awards, News, Projects

KJ’s Tualatin Interceptor and Siphon Improvements Project Wins Oregon Chapter APWA Award – ‘2020 Project of the Year’


This progressive design-build project is a critical upgrade to a 42-year old interceptor system in Washington County, Oregon. The project is a major trunk sewer feeding the Durham Advanced Wastewater Treatment Facility which receives wastewater from the Sherwood and Bull Mountain areas. On October 22, the Oregon Chapter of the American Public Works Association awarded it the ‘2020 Project of the Year Award’ in the category of Environmental, $25 million to $75 million.


Photo 2: KJ’s Oregon Tualatin Interceptor and Siphon Improvements Project


KJ collaborated with contractors Mortenson Construction, K&E Excavating, and Michels Tunneling on this project for client, Clean Water Services (CWS). At the outset, CWS commissioned a planning study that identified deficiencies in the interceptor capacity.

The existing interceptor, ranging from 24-inch to 42-inch diameter, was replaced with new pipe ranging from 60-inch to 66-inch diameter. Kennedy Jenks worked with Shannon & Wilson and Aldea Services to prepare the design of the Tualatin River Crossing from King City to Tualatin.

The team provided vital constructability and cost feedback to the design team. The design covered projected sewer capacity requirements, geotechnical conditions, seismic risk, constructability, maintainability, and stakeholder concerns to provide a long-term solution for CWS.

Phase A of the project included the most restrictive conveyance segment in the Interceptor, the King City Siphon, which would convey wastewater from a new River Terrace North Pump Station and surrounding residential areas across the Tualatin River. Selection of a microtunnel for the Siphon enabled construction without impact to the Tualatin River. The 650-foot vertical curve set a North American record for tightest vertical curve microtunnel of this diameter.

Phase B of the project included crossing State and City-owned roads, more than 30 privately-owned properties, a second Tualatin River Crossing, two constructed wetland crossings, two City Park crossings, and connection to CWS’ Durham wastewater treatment plant.

“Kennedy Jenks, Shannon & Wilson, and Aldea were very responsive and worked closely with the district and constructors to complete a complex and challenging project on time and under budget,” noted Wade Denny, P.E., Sr. Engineer, Clean Water Services.

No stranger to awards and celebrity, this outstanding project won an ACEC Engineering Excellence Award earlier this year: ACEC 2020 Excellence Awards and was featured in Engineering News-Record: here.

Key team members: Dean Wood, Rob Peacock, Mark Nelson, Mark Cullington, Ed Barnhurst, Chad Cadiente, Stan Lasselle, Sundeep Kaur, Dana Devin-Clarke, Amanda Mesick, Steve Pritchett, Bryan Hoffer, Bronwyn Rolph, Michelle Flury and RoVawn Rouse. Thanks to the many other KJers who played a role in this winning project.


Congratulations to our Oregon winning team!


Share This Article