Larsen briefed by officials on plans to improve fish passage, reduce flooding on lower Perrinville Creek

U.S. Rep. Rick Larsen met on Tuesday morning with officials from the City of Edmonds and the Tulalip Tribes, who briefed him on a proposed project that would remove culverts and other obstructions to fish passage on the lower 150 meters of Perrinville Creek and create a free-flowing, fish-friendly stream flowing into Puget Sound.

The tribes recently applied for a $37 million U.S. Department of Transportation (USDOT) National Culvert Removal Replacement and Restoration grant to help fund this and 20 other projects addressing high-priority fish passage barriers. They would partner with BNSF, Snohomish County and the cities of Everett, Edmonds and Arlington in this effort.

Last month, Larsen threw his support behind the grant application in a letter to the USDOT. The letter cited the benefits of improving and expanding upstream habitat, restoring salmon populations upon which Southern Resident killer whales depend for a food source, enhancing climate change resilience, reducing flood hazards, and fostering ecological connectivity and natural processes.

“I’m excited about this project,” Larsen said. “Culvert replacement programs like this are a high priority to help with salmon recovery. It’s not just Perrinville Creek — this grant would support salmon recovery throughout the Puget Sound region.”

As one of several projects under the grant proposal, Perrinville Creek is not atypical of the situations that the culvert removal program aims to address.

As it heads into Puget Sound, the final section of Perrinville Creek travels through a 30-inch culvert under Talbot Road — emerging on the west side in a steep drop that forms an “effective block to migrating fish,” said Todd Zackey of the Tulalip Tribes.

And this is only the first of several other fish barriers along the creek’s short but critical route to Puget Sound.

The next is just west of Talbot Road, where the creek flows mix with stormwater runoff and enter a high-flow bypass system constructed in 1994 by the City of Edmonds. Comprised of two catch basin-like structures, the system was designed to control flooding by limiting the amount of water flowing through private property during high flows by diverting the excess through a 42-inch underground overflow pipe (labeled City Pipe in the illustration below). The remainder passes through private property and finally into a 30-inch concrete pipe running under the BNSF tracks and into Puget Sound (labeled BNSF Pipe below). Note in the illustration that this route takes the water through a series of 90-degree bends that can both trap sediment and confuse fish.

The proposed project would eliminate the Talbot Road culvert and thus keep creek flows from mixing with storm water and entering the high-flow bypass diversion system.  Creek flows would be diverted to a more natural stream bed that would smooth out the 90-degree bends to create a more meandering route. A bridge or exposed culvert under the BNSF tracks would form the new mouth of the creek as it exits into Puget Sound.  Storm water would continue to be discharged into Puget Sound via the City Pipe, but since it would no longer be mixed with Perrinville Creek water it would not carry the creek’s chemical signature that serves as a homing signal to salmon.  That signal would only come from the water entering the Sound at the new mouth of Perrinville Creek.

“Moving ahead with this is all dependent on grant approval,” explained Edmonds Chief Utilities Engineer Mike DeLilla. “Once funding is in place, we can proceed with the design and permitting processes – and of course, any field work would have to be scheduled around fish windows. If all goes well, we could start work in about a year, with actual construction out a bit further. There’s lots of variables.”

— Story and photos by Larry Vogel