Located on State Route 203 in Duvall, Washington, the Loutsis Creek Fish Passage project involved the replacement of a nearly century-old fish-blocking culvert with a composite arch structure that allows the creek to flow freely underneath. In addition to creating a more natural creek bed, the new structure provides access to an additional 3.1 miles of upstream habitat and spawning grounds for Coho salmon, steelhead, coastal cutthroat trout, and other species. This project is part of Washington State’s long-term effort to save endangered and threatened fish species by eliminating fish passage barriers statewide.
After the existing concrete culvert was removed, a 50-foot-long carbon-fiber arch bridge was installed over Loutsis Creek. Nicknamed “bridge-in-a-backpack,” the composite arch structure is the first of its kind west of the Mississippi. GBI crews constructed structural earth headwalls and wing walls, backfilled the arch, and repaved the highway. Additionally, the creek bed was restored to its natural state with meanders, rocks, logs, and vegetation.
Most of the work took place during a five-week-long closure of State Route 203. During that time, two diesel pumps were used to bypass the stream so the existing embankment could be removed. Five days before the anticipated 38-day road closure, the Washington State Department of Transportation (WSDOT) learned that King County had scheduled its own work at the same time on the proposed detour route. There was only one other detour route available, which added 50 minutes to residents’ commute time. As a result, WSDOT instructed GBI to accelerate the schedule by any means necessary. Given the complexity of the project, this presented a significant challenge. Determined to meet the challenge, GBI reconfigured several tasks and worked 24 hours a day, six days a week. GBI ultimately reopened the road on the 34th day, despite several delays resulting from increased earthwork quantities related to ground conditions.
WSDOT was appreciative of GBI’s determined effort to reopen State Route 203 ahead of schedule, and the following winter, it awarded GBI an emergency contract for a project on the same highway. GBI also received an Associated General Contractors of Washington/WSDOT Partnership for Excellence in Contract Administration Award for this project. These awards recognize contractor/WSDOT partnerships that have delivered transportation projects in a timely, professional, and responsive manner, while also considering the needs of those affected by the project. Additionally, the Loutsis Creek Fish Passage project earned an American Society of Civil Engineering Local Outstanding Civil Engineering Achievement Award (LOCEA) in the category of Outstanding Structures Project. The LOCEA Awards recognize projects that have improved the quality of life and contributed to the economic development of the local community, area, or region.
American Society of Civil Engineering Local Outstanding Civil Engineering Award (Outstanding Structures Project Category)
AGC/WSDOT Partnership for Excellence in Contract Administration Award, Honorable Mention (Western Washington Projects, $3-10 million)