Keeping Salmon Swimming: How Designed Groundwater Services and Thompson Pump Are Helping Washington Meet a $7.8 Billion Fish Passage Challenge
When the water slows to a trickle in a salmon-bearing stream, it’s more than an environmental inconvenience – it’s a threat to an entire ecosystem, a cultural tradition, and in Washington State, a matter of federal law.
In 2013, a federal court ordered the State of Washington to repair or replace more than 1,000 roadway culverts that were blocking salmon from reaching their upstream spawning grounds. The decision came after 21 Native American tribes sued the state, arguing that the crumbling and undersized culverts violated their treaty rights by cutting off salmon migration routes.
The court’s mandate requires high-priority culverts to be fixed or replaced by 2030. However, since the original ruling, the scope and cost of the work have expanded dramatically. What sounded straightforward on paper quickly turned into one of the largest, costliest, and most complex environmental infrastructure undertakings in the country.
· 2018 estimate: Approximately $1.88 billion total, with an average cost of $5 million per culvert.
· 2025 projection: Around $7.8 billion total, with some culverts now costing $20 million each to replace.
Box Culvert Installation on Highway 167 in Auburn, WA (2017)
Credit: Designed Groundwater Services
So, what happened? The short answer: complexity. Many of these culverts run under major highways, through wetlands, or in areas with high groundwater tables. Rising construction costs, more stringent environmental protections, and the engineering challenges of working in sensitive habitats have pushed costs higher.
Then there is timing. Crews can only work during the “fish window” – July through September – when salmon aren’t migrating upstream. That gives contractors just three months a year to get in, do the work, and get out without disrupting the salmon they are trying to save.
Dewatering: The Key to Success
Replacing a culvert isn’t just about digging out the old pipe and dropping in a new one. In many locations, the worksite is underwater – or close to it. Without careful dewatering, heavy equipment can’t operate, concrete can’t be poured, and crews can’t work safely.
That’s where Designed Groundwater Services (DGS) comes in.
Salmon Passage Installation at Joint Base Lewis-McChord Airfield in Tacoma, WA (2020)
Credit: Designed Groundwater Services
Over the years, DGS has built a reputation as Washington’s most experienced wellpoint dewatering contractor, with the largest fleet of Thompson Pump and Manufacturing Company’s rotary wellpoint pumps in the state. DGS has been on the front lines of fish passage projects for years, supporting general contractors with systems that keep jobsites dry and stable.
“When you’re replacing a culvert under a highway, you’re often dealing with a deep excavation, high groundwater, and traffic moving just feet away,” said Gary Fors, Owner of DGS. “The right dewatering system isn’t just helpful – it’s the only way the project can happen.”
The Thompson Pump Advantage
At the heart of DGS’s success is its fleet of Thompson Pumps, known industry-wide for their reliability, efficiency, and ability to handle demanding wellpoint applications. For fish passage work, where crews are racing against the calendar and environmental restrictions, reliability is priceless.
Thompson Pump’s Rotary Wellpoint, positive displacement pumps are the original rotary pumps trusted by contractors worldwide for more than 50 years. They are specifically designed and engineered for construction wellpoint and sock dewatering with high air handling, large water volume, and high vacuum capability.
Salmon Passage Culvert Installation on Highway 101 Near Quinault, WA (2025)
Credit: Designed Groundwater Services
The rotary wellpoint pumps draw down groundwater across large excavations, preventing dangerous instability in the soil. DGS installs wellpoints on close centers at the top of slopes on both sides of a large open-cut excavation. Then, using the Thompson Rotary Wellpoint Pumps, the system maintains a consistent drawdown so contractors can safely remove the old structure and install a new, fish-friendly box culvert.
The engineering doesn’t stop there. DGS often installs wellpoint risers within the highway, building protective covers and burying them temporarily so traffic can pass over without damaging the integrity of the system. The risers then connect to a header pipe system and a pump that is strategically located on the shoulder of the road to keep the pumps accessible and out of the way.
Big Jobs, Big Systems
Over the past decade, DGS has handled some of the largest and most logistically complex dewatering efforts in Washington’s fish passage program.
Salmon Passage Installation at Joint Base Lewis-McChord Airfield in Tacoma, WA (2020)
Credit: Designed Groundwater Services
One standout project was at Joint Base Lewis-McChord Airfield in Tacoma in 2020. DGS was contracted to dewater a 1,800-foot-long arch culvert on both sides of the runway – a massive job requiring 13 separate 12-inch Thompson Rotary Pumps running simultaneously. The setup kept groundwater in check for months, while crews worked under the runway.
In 2023, when DGS partnered with Kiewit Corporation, one of the country's largest and most respected construction and engineering organizations, the demand for the company’s services surged, prompting DGS to invest in additional piston pumps and expand capacity.
By 2025, DGS was running eight box culvert dewatering projects simultaneously along Highways 101 and 109 on the Pacific coast near Quinault. Each site was designed for two 6-inch Thompson Piston Pumps, all running during the narrow “fish window”. The scale of the operation is a testament to DGS’s capacity and Thompson Pump’s reliability.
The Stakes Are High
While much of the conversation around the culvert program focuses on budgets and deadlines, the real driver is the salmon. These fish are central to the culture, economy, and ecology of the Pacific Northwest. For native American tribes, salmon are more than a resource; they’re a living link to heritage and identity.
Blocked culverts don’t just inconvenience salmon – they can wipe out entire runs by cutting fish off from the upstream habitat they need to spawn. Restoring those pathways is critical to reversing decades of decline.
Precision, Speed, and Reliability
Working in the “fish window” adds pressure to every phase of a project. DGS’s crews often mobilize multiple Thompson Pump systems in quick succession, running 24/7 operations to keep excavations dry so construction can stay on schedule.
Salmon Passage Culvert Installation on Highway 101 Near Quinault, WA (2025)
Credit: Designed Groundwater Services
“If our pumps go down, everything stops,” said Fors. “With Thompson Pump, that just doesn’t happen. They run, and they keep running.”
This reliability allows contractors to focus on building, knowing the water table is under control. It also minimizes environmental risks.
Looking Ahead
With hundreds of culverts still to be replaced before the 2030 deadline, the Washington State fish passage program is one of the most ambitious environmental infrastructure efforts in the country, and far from over. Costs will likely continue to rise, and timelines will remain tight. For DGS, that means staying ready – expanding capacity, refining techniques, and keeping the Thompson Pump fleet in peak condition – as the company continues to play a pivotal role in restoring vital salmon habitats and honoring the treaty rights of Native American tribes.
“It’s not just about finishing a project,” said Fors. “It’s about making sure the salmon can get where they need to go for generations to come. That’s something we’re proud to be part of.”
About Designed Groundwater Services
Designed Groundwater Services is a full-service dewatering sub-contractor in Washington and the leader in wellpoint dewatering, with the largest fleet of Thompson Pumps in the state and decades of experience supporting complex infrastructure projects. From fish passage culverts to large-scale roadway excavations, DGS delivers the system, expertise, and reliability that keep construction moving – no matter how challenging the groundwater conditions.
About Thompson Pump and Manufacturing Company
An ISO 9001, 45001, and 14001 Certified company, Thompson Pump and Manufacturing Company is an award-winning, full-service manufacturer and provider of high-quality, high-performance pumps, pumping equipment, and engineering expertise for bypass pumping, dewatering, mining, and flood control. Thompson Pump defines what is “state-of-the-art” in the industry and is dedicated to producing new and innovative dewatering and construction pump products. Family-owned and operated for 55 years, Thompson Pump continually seeks innovative and creative talent to join the team. For more, visit thompsonpump.com.
You can also read about this project in Pumps & Systems.