Fort Steilacoom Park’s Waughop Lake could require removal of more than three feet of nutrient-rich sludge from its bottom to kill toxic blue-green algae blooms that have plagued it for years, a consultant told the Lakewood City Council this week.
The environmental engineering firm Brown and Caldwell said dredging the lake at a cost of $2.7 to $15 million isn’t the only cure for the blooms. Treating the lake with alum could temporarily reduce the growth of the algae, but it would require periodic renewal to keep the growth under control. The initial cost for that treatment is estimated at $210,000.
The lake has been posted by the Tacoma-Pierce County Health Department as dangerous to swimmers, pets and those who eat fish from it.
The city hired Brown and Caldwell in 2014 to produce a lake management plan. The plan cost $250,000, funded by the state Department of Ecology. The plan’s authors, Brown and Caldwell vice president Mike Milne and University of Washington Tacoma associate professor Jim Gawel, presented the plan’s findings Monday night to the council.
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The study recommended a two-phase approach to the lake’s problems. The first phase would be treatment with alum. The second phase would be dredging the lake. The alum would bind with phosphorus in the water, forming a substance that would fall to the lake bottom and trap the phosphorus in the sediments, keeping it from spreading to the lake water. That barrier, however, could lose its effectiveness after a few years, said engineers.
Two longtime Waughop Lake advocates, Tom McClellan and Don Russell, say the city should skip alum and proceed directly toward the more sustainable solution of dredging.
The two men have monitored the lake’s chemistry and plant life for years as volunteers. McClellan is a financial newsletter author, and Russell is a retired chemist, biologist and businessman. The pair were co-authors of a lengthy report three years ago advocating dredging the lake to eliminate its recurring issues.
“The city took our report and said ‘Thank you very much,’ and never did anything,” said McClellan, who almost daily walks his two dogs, Libby and Gracie, around the lake’s nearly one-mile circumference.
The lay study and the engineering firm’s plan agree that the preferred solution is dredging the lake bottom, where years of organic sludge from former farming operations feeds the blue-green algae. But Russell and McClellan worry that Lakewood, faced with a pricey dredging bill, will make the situation worse by settling for alum treatments alone.
Russell, who has monitored all of Lakewood’s major lakes for 17 years for the Pierce County Conservation District, said that while alum treatment would temporarily clear the Waughop’s water, the lake likely would be soon overcome by explosive growth of aquatic weeds. Those weeds would flourish, he contended, because the lake’s clearer water would admit more sunlight, and the nitrogen in the sediment would fertilize the plants.
Lakewood leases the park from the state. The 350-acre park was once an active part of Western State Hospital. Under the state’s management, the land was used as a farm where patients raised livestock and crops. At one time, a slaughterhouse was built over part of the lake with the waste from that process dumped directly into the water.
The city has yet to secure money for any solution. One of the options being considered, said Greg Vigoren, Lakewood’s surface water division manager, is to pay for the alum treatments by raising the surface water fees charged property owners. The city has hired a consulting firm to recommend changes to those fees.
Dredging likely would be too expensive to pay for with those fees, Vigoren said.
“We’re talking about some very heavy lifting,” he said. The city could search for grants or a legislative appropriation to pay the cost of dredging, he said.
The Lakewood City Council is scheduled to consider further action on lake cleanup at its meeting Monday night.
Meanwhile, Pierce College has taken remedial measures to prevent a sewage overflow from the nearby college into the lake. An overloaded sewage lift station on the campus last month dumped sewage into an outfall that feeds the lake. The college has capped that connection to the sanitary system, said Pierce College spokesman Brian Benedetti.
Benedetti said the college hired an engineering firm to design a new, higher capacity lift station to replace the station that dated from the college’s opening, decades ago. Meanwhile, an environmental cleanup firm is flushing and vacuuming the pipes through which the sewage reached the lake.
John Gillie: 253-597-8663