Longview wants new water treatment plant
Friday, February 16, 2007 11:45 PM PST
By Amy M. E. Fischer
Printable version
E-mail this articleLongview's aging water treatment plant can't handle the increasing amount of volcanic silt in the Cowlitz River, say city officials, who recommend building a $26 million new plant rather than upgrading the old one.
Either of those options would mean a sharp rate increase for water customers --- possibly by more than 50 percent over the next four years, depending on how much federal and state money the city receives for the project, Longview Public Works Director Jeff Cameron said.
According to the city's projections, residential customers' water bills could rise by about $13 a month, from an average rate of roughly $21 to $34.
"We understand the burden on the ratepayers, and we're doing our best to minimize it," Cameron said Friday, a day after presenting his recommendation at a City Council workshop.
Thursday, the council agreed to seek state approval for plans for a new plant, which would draw water from an aquifer rather than the Cowlitz River. Several wells would be drilled at the Mint Farm Industrial Park, and the water would be treated at the new plant, which would require a 2-acre site, Cameron said. The old plant would be abandoned.
"Obviously, the money is a big concern, but (council members) see the need to do it," Cameron said Friday. Building a new treatment plant, from design phase through construction, would take 20 to 33 months, he said.
The council will formally vote on whether to proceed with building a new plant after the state health department approves the plans, he said.
Equipment at the plant on Fishers Lane is wearing out because the Cowlitz River water contains so much silt, he said. Mud stirred up by winter storms used to settle faster, but now it can take months, he said. As a result, the circa-1944 treatment plant has struggled to meet local demand for drinking water.
The sediment problem is a lingering aftereffect of Mount St. Helens' eruption nearly 27 years ago, when a sea of mud and logs washed from the Toutle River into the Cowlitz River. To control flooding, the U.S. Army Corps of Engineers built a sediment retention dam on the north fork of the Toutle River in the late 1980s.
Today, that sediment retention dam is almost full and doesn't trap silt efficiently, Cameron said. The corps plans to dredge the mouth of the Toutle River in November, but that won't reduce the water's turbidity.
Two years ago, the city built a dam in front of the treatment plant's water intake pipe, but now, the river bottom is rising over the top of the dam, he said. When the river flow drops in the summer, the intake pipe could be left high and dry.
"Given the sediment problem in the river, we didn't feel it was prudent to spend money to upgrade the existing plant," said Cameron, who estimates such an upgrade would cost $15 million.
The problem with installing a new sediment-control system is "none of our technical experts can assure us that it'll work," he said.
The city hopes the federal government will see the link between the volcanic eruption and the muddy river and help fund a new water treatment plant, Cameron said.
By tapping into the aquifer, the city would have a reliable, clean and bountiful water supply requiring far less treatment than the muddy river water, Cameron said. The Mint Farm would be an ideal place to drill the wells because the water, which flows underground from north to south, wouldn't be at risk for contamination from heavy industries to the south, a hydrogeologist told the city.
City employees asked the hydrogeologist about whether the Mint Farm's ethanol plant might pose a hazard, "and he was not concerned about that at all," Cameron said. That's because the lower aquifer is under pressure, like an artesian well. The pressure would keep any contaminants near the surface, Cameron said.
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