The City of Montesano has established a schedule to deal with its waste water treatment plant issue. The situation at the plant has been called an ecological disaster in the making.
The wastewater treatment plant is located on a bank of the Wynoochee River. The river has completely eroded the western bank and now has begun to erode the land north of the treatment plant. If the situation is not addressed, stakeholders fear the river will completely erode away the land surrounding the plant, turning the wastewater plant into an island.
In the past decade, sheet pile was installed to protect the western edge of the plant. The sheet pile walls were successful in protecting the wall of the treatment plant, but the sheet pile had the unintended consequence of creating a 40-foot-deep pocket in the river at the western wall. That could mean the river has a chance to undercut the sheet pile if the situation is not addressed.
In a presentation to the Montesano City Council on Feb. 13, public works director Mike Olden said the solution will cost about $10 million total.
The city is planning to move the sludge pond and effluent away from the river. Along the river, north of the treatment plant, the city plans to put down river jacks. River jacks are man-made structures constructed of a boulder and logs. As the river erodes the bank, the river jacks fall into the water. River jacks are engineered to trap sediment. As sediment builds around the river jacks, the current slows. With slower current, there will be less bank erosion.
Eventually, the city hopes to open a relic channel on the western bank of the river across the stream for the treatment plant. With a slower current on the treatment plant bank and an open path on the western bank, it’s hoped the river will redirect away from the treatment plant.
Log jacks will cost $1.5 million, sludge pond relocation will cost $4 million, effluent relocation will cost $1.5 million and opening the relic channel will cost $3 million.
The project is partially funded through state funds. The capital budget approved in January included $5 million for the project.
The city also is hoping to receive a grant from Floodplains By Design, a public-private partnership led by The Nature Conservancy, the state Department of Ecology and Puget Sound Partnership. The city has applied for a $3 million grant.
The city would need to cover about $2 million for the project.
Currently, it looks like the project could be complete by September 2020, including opening the relic channel.
Permitting and design will take place beginning this month through July. The log jacks will be installed in April through October. Both the sludge pond and effluent would be relocated beginning in July this year through to September 2019. Opening the relic channel wouldn’t begin until next year and is scheduled to be a work in progress until September 2020.
The design contract was awarded to Parametrix.
During the Feb. 13 council meeting, Councilman Dan Wood expressed his frustrations at Olden for comments made at Wood’s expense during a committee meeting discussing the wastewater treatment plant. Details of those comments were not discussed.