LAKE FOREST PARK – About 3,000 Lake Forest Park residences get their water from wells that draw from an underground aquifer. Protecting this water source is of key concern for the Lake Forest Park Water District, especially with King County planning to build a $1.3 billion waste water treatment system nearby, with pipes running beneath the city.
While the county is still deciding on a final location for the plant called Brightwater that will serve North King and South Snohomish counties, County Executive Ron Sims announced a year ago that the preferred site location is in Woodinville, and the preferred pipe routes will carry treated wastewater through Lake Forest Park to Puget Sound at Point Wells in Shoreline.
The Lake Forest Park Water District wants the county to guarantee the tunnel will be dug below the aquifer, so the aquifer won’t be penetrated, drained or polluted. If the aquifer is penetrated, the water district wants the county to agree to the highest mitigation possible to protect the city’s water.
“Our concern is that the drilling of the tunnel will drain the aquifer,” said Gordon Hungar, president of the Lake Forest Park Water Commission. “Also, the deeper you go, the greater the pressure, so when you go 300 feet down, pipes leak… They know it is going to leak, they all do, but our problem is how much will they leak?”
According to the design, the tunnels are concrete sectional tunnels. The drilling machine bores a hole through the ground and it’s lined with concrete. If these tunnels go through the aquifer, water could leak out of the aquifer where the tunnel cuts through, and potentially drain the aquifer, eliminating the district’s water source, said Dan Mundall, engineer for the water district.
There is also potential, depending on the tunnel alignment, for treated waste water to leak out of the tunnel into the aquifer, polluting the water source.
King County officials say the county plans to dig the tunnel well below the aquifer, through dense clay, or “aquitard.”
Christie True, with Brightwater, said since the county published its Draft Environmental Impact Statement in Nov. 2002, it’s been negotiating with Lake Forest Park water district and digging test wells to evaluate where the tunnel might go.
“We have been doing geotechnical testing to find out more about how this project may affect the aquifer because there is not a lot known about this aquifer. Our goal is that we not go through their aquifer, and instead be able to find a zone of clay to put the tunnel through that will be below their aquifer,” True said.
Lake Forest Park Water District officials say they want proof.
“They’ve dug dozens of test wells and the one they dug where we think our aquifer is, failed,” Hungar said. “They got down to where the water is, but didn’t go beyond that, so they know where the aquifer is, but don’t know where the layer of clay is,” Hungar said.
District officials also want the county to agree on various modes of action it will take to protect the city’s water source if the aquifer is pierced.
“We want assurance that if the tunnel goes through the middle of our aquifer, they will use every mitigation known, such as putting pipes inside of pipes, using plastic lining and anything else to protect our aquifer,” Hungar said. “We also want the tunnel to be inspected more regularly than what the county proposes – every 15 years.”
The commission wants this agreement signed before the county comes out with its Final Environmental Impact Statement (FEIS), due in November.
True said the FEIS is not a deadline. The county has not agreed to double piping or plastic lining the tunnel in this area because it plans to dig the tunnel through clay, not the aquifer. Testing the depth of the aquifer will continue even after the November release of the FEIS.
“We have been working with the water district through the investigation and design, and we will continue to work with them to monitor their wells during and after construction. We are all in agreement the water supply needs to be protected,” True said.
She also points out that the county already has a mitigation plan in mind.
If the aquifer is penetrated, “people will not go without water,” True said. “We have a plan in place to hook these customers up to other water services. We could hook them up to Seattle City water.”
Hungar said that’s the cheap and easy way out.
“It gets down to money. If you have to double line your tunnel and put another pipe inside, and inspect it on a more regular basis, that’s money, and we are talking about billions of dollars. And who are we, if they can turn around and hook us up to Seattle water, it may be a lot cheaper for them, but Seattle water will be four or five times more expensive for our customers,” Hungar said. “And our customers appreciate their water being naturally pure and unchlorinated.”
Metro King County Council member Carolyn Edmonds arranged a meeting with Lake Forest Park Water District commission last month to hear their concerns.
“The reality is that they are a small water district in a very big project,” Edmonds said. “But their concerns are valid, and I have every reason to believe we will be able to address them.”
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