King County Looks To Hurricanes Sandy, Katrina For Lessons On Crippled Sewage Plant

Mar 2, 2017

Three weeks after floodwaters crippled a major Seattle sewage treatment plant, a clearer picture of the damage is emerging.

King County's wastewater treatment director, Mark Isaacson, said the flooding that occurred Feb. 9 is unlike anything the West Point Treatment Plant has seen in its 50-year history. 

For lessons on how to respond, he said, officials are studying Hurricane Sandy, which crippled treatment plants on the East Coast in 2012, and Hurricane Katrina, which devastated the Gulf Coast in 2005.

"We are doing research on the recovery efforts and what it takes," Isaacson told the King County Council's Regional Water Quality Committee on Wednesday.

Some committee members grew frustrated when wastewater division staff declined to estimate when the plant would be fully operation again. 

West Point is discharging partially-treated wastewater into Puget Sound and is operating at about half capacity. County officials said the reduced capacity isn't a problem in normal weather conditions, but two to three days of steady rain could overwhelm the plant.

For days immediately after the flooding, completely untreated wastewater spilled into Puget Sound.

Isaacson said he wasn't ready to release an estimate on when repairs would be done. Wastewater division staff are investigating the precise cause of the flooding.

The problems started with an early morning power outage that crippled the pumps at West Point.

Isaacson said it took 10 minutes for sewage and rainwater to fill a mile of 12- to 14-foot-tall tunnels under the plant. Hundreds of pumps, motors, lights, and electrical transformers need to be replaced.

Insurance adjusters estimated the damages at $25 million after a preliminary walkthrough, but that figure is likely to rise, Isaacson said.

West Point, located next to Discovery Park in Seattle's Magnolia neighborhood, serves more than 1.5 million people in and around the city.