Centralia Approves the Purchase of System to Filter Debris From Water for Yelm Hydro Project

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The Centralia City Council approved the sole source purchase of a “trash rack raking system” for the Yelm Hydro Project, for an amount not to exceed $414,000, which will filter debris on the Nisqually River before it goes through the canal and ends up in the hydroelectric turbines that produce green electrical power.

The Yelm Hydro Project is operated by Centralia City Light and can produce up to 11 to 12 Megawatts of green electrical power. The existing trash rack raking system has been in place for over 30 years, is worn and requires frequent and often difficult repairs, according to the agenda report.

The water from the Nisqually River flows down a 9.1-mile canal, through a reservoir that feeds into two pipes and then makes its way into three hydroelectric turbines that output the water back into the river, M.L. Norton, Centralia City Light general manager explained to the council. 

“You can imagine that in 9.1 miles there is a good deal of debris that can fall into the canal so we have to get it out at the end,” said Norton.

The $414,000, which includes tax, is already included in the city’s current budget.

“The Nisqually River begins on Mt. Rainier as a glacial melt. It is very clean and provides a nourishing and safe habitat to thousands of fish,” states the agenda report.



The trash rack raking system is electric and automatic and is patented by Hydro Component Systems, LLC of Watertown, WI. Norton said that the Yelm Hydro Project crew did not identify any alternative. 

“We want to avoid hydraulic oil, or oil of any kind, over the water as it goes down through your hydro turbines and back into the river. We have a very good working relationship with the Nisqually Indian Tribe and we try to keep their water pristine,” said Norton.

Norton said that the Yelm Hydro Project crew found that the new trash rack raking system will not threaten the river and the fish with oil pollution.

“It’s very attractive, very safe, safe for the fish and for our relationship with the Nisqually Tribe so this what we are asking you to approve tonight,” said Norton.