Flow Technologies Pulls Off Emergency CIPP Repair Under Washington Flood Embankment

Flow Technologies Pulls Off Emergency CIPP Repair Under Washington Flood Embankment

According to Trenchless Technology, Flow Technologies Inc. completed an emergency cured-in-place pipe (CIPP) rehabilitation of a failing 8-inch concrete gravity sewer main for the Woodinville Water District in Washington, with the pipe buried 16 feet beneath a flood control embankment just 30 feet from the Snoqualmie River.

A Tough Job in a Tougher Location

The call came in late October, during high-water season on the Snoqualmie River, adding environmental and logistical pressure to an already difficult project. The sewer segment had 100% sags and visible soil intrusion at multiple locations, signs of advanced structural failure. Conventional open-cut repair was not a realistic option given the depth, the proximity to the river, and the risk of destabilizing the flood embankment.

Flow Technologies and the water district met onsite to plan the approach. The crew used CCTV inspection and precision dewatering to assess conditions and halt further deterioration before the liner was designed, ordered, and wet-out for installation. The liner design called for a 6-mil finish cure. A pull-in-place pre-liner was installed first to protect the felt and prevent resin migration. The final CIPP installation was completed using inversion equipment from Emagineered Solutions, specifically their air inversion unit called The Shooter, maintaining positive air pressure throughout with no interruptions during the inversion process.

Extra precautions were taken to protect surrounding vegetation, root systems, and the structural integrity of the flood embankment itself.

What It Means for Subcontractors

• Emergency response capability is a competitive differentiator. Municipal clients facing urgent infrastructure failures need contractors who can assess, plan, and mobilize fast. Being positioned as that call is a business development strategy, not just an operational one.
• Environmental constraints are increasingly part of trenchless bids. This job required protecting riparian vegetation, flood control structures, and a nearby river. Subcontractors who can demonstrate environmental compliance and site-specific planning will win work others can’t take on.
• Equipment selection matters on restricted-access jobs. The use of The Shooter for air inversion allowed a continuous, no-stop installation in a location where a failed pull or restart could have had serious consequences. Knowing your equipment’s capabilities, and having the right partnerships, directly affects project outcomes.
• CIPP remains the go-to solution for difficult easements. When a pipe is buried 16 feet under a flood embankment with a river nearby, trenchless isn’t just preferred, it’s the only viable path. Contractors with CIPP expertise and proven project references are well-positioned as aging municipal infrastructure continues to fail across the Pacific Northwest and beyond.