Investigators probing why raw sewage is flowing into Lakewood’s Waughop Lake have found the source of the contamination: a cross connection between Pierce College’s sanitary sewer system and its storm sewer system that allows sewage overflows to reach the lake.
Brian Benedetti, a Pierce College spokesman, said Wednesday the college has hired a contractor to dig up and cap the connection. The college also is beginning to flush the storm sewer to prevent accumulated sewage in that pipe from flowing into the lake at Fort Steilacoom Park.
Pierce College had sent vacuum trucks to the lake Tuesday to remove floating sewage that had been discovered.
Contractors soon will begin replacing a 1971-vintage lift station with a new one with greater capacity and safeguards to prevent sewage from reaching the stormwater system. That lift station will route sewage from part of the campus into the sanitary sewer system.
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Mary Dodsworth of Lakewood Parks, Recreation and Community Services said the lake has suffered for years with intermittent contamination problems.
Waughop is a “kettle lake” formed by a retreating glacier. As such, the 33-acre lake has no outlet other than seepage into the water table through the lake bottom. The lake is fed by rain, by storm runoff from the campus and possibly from local springs.
The Tacoma-Pierce County Health Department this month issued a health advisory for the lake, warning residents and their pets not to swim, fish or contact the lake water.
At first, researchers suspected the lake was being contaminated by nearby septic drain fields, leaking sewage pipes or by lawn chemicals. Studies showed those weren’t major factors in its problems.
The storm sewer drain from the campus was a suspect, but investigators couldn’t tie its outfall to the problem because contamination was intermittent. This week’s investigation discovered that during power outages or when the demand was greater than the station could handle, the waste apparently flowed into the stormwater system and then into the lake.
Benedetti said the sewage pump station was built 45 years ago, when the college opened.
“The pollution standards then probably weren’t as strict as they are now,” he said.
The lake had a history of contamination even before the college was built, Dodsworth said.
The park property and the lake once were part of the Western State Hospital campus. The mental health hospital operated a farm on the property for decades, until it was shut down in 1965. The farm included a slaughterhouse built partially over the lake, Dodsworth said.
“When they slaughtered the animals, steaks went in one bin, and the rest of the animal probably went in the lake,” she said.
A previous investigation found the lake bottom is covered with a thick layer of organic waste that produces nutrients that feed the algae growth and impedes the flow of lake water into the ground. The lake has been prone for years to developing growths of toxic blue-green algae, especially in warm weather. The algae is feed by nutrients introduced into the lake from runoff.
John Gillie: 253-597-8663