Representatives from the city of Issaquah recently tried to assure their neighbors to the north there’s no reason to worry about the potential injection of stormwater runoff into an aquifer that serves 54,000 Sammamish residents.
Speaking on behalf of the Issaquah mayor’s office at the May 20 Sammamish City Council meeting, Dan Ervin, vice president of RH2 Engineering, Inc., told councilmembers the practice is widely used.
“This is a very conventional stormwater disposal device,” Ervin said. “There are hundreds, thousands of these throughout western Washington. Virtually every community has a similar situation — this facility that’s under discussion tonight is neither unusual nor unique.”
The “facility” Ervin referred to is the Lower Reid Infiltration Gallery, or LRIG — a controversial football-field shaped piece of land at the foot of the Issaquah Highlands. The piece of property, called a vadose zone, uses sand and gravel to naturally filtrate contaminants before they reach an underground aquifer.
Issaquah, which owns the LRIG, is seeking a permit from the Department of Ecology to continue a testing program for an undetermined amount of time where it would be allowed to inject stormwater into the aquifer — a practice Ecology forced the city to stop in 2008 after finding a high level of contaminants.
The Sammamish Plateau Water & Sewer District has voiced its concerns over the return to such a practice — largely because it has three wells nearby, including one 600 feet downhill.
Ervin told the Sammamish Council Issaquah has monitored the stormwater since it was forced to cease injection. He said recent tests have returned minimal positive results in two areas of concern — iron and total coliform. Out of 27 samples, he said two exceeded the drinking water standard for iron and one for total coliform.
Ervin explained the city’s next step is to prove to Ecology it can eliminate all coliform through filtration.
“If we can show through an enhanced monitoring program and continued operation that we routinely can remove any coliform that might be present, then the presumption is we’ll be able to operate the facility,” he said.
Gail Twelves, a consultant for the Sammamish Plateau Water & Sewer District, said she was concerned Ervin made no mention of fecal coliform — a contaminant she said is the largest offender from the Highlands.
“Fecal coliform is from poop and it carries a whole host of viruses and diseases attached to it and it can remain virulent in ground water for months,” she said. “Fecal coliform is also a very small particle that passes through sand/gravel soil very easily.”
Twelves said District results showed fecal coliform at 5000 Colony Forming Units, or live bacteria — a number she says is off the charts.
Concerned with Issaquah’s presentation, several Sammamish councilmembers asked questions, including about the sustainability of the LRIG.
“I’m looking at all this stuff going in there, after 10 or 15, 20 years how will you change the filter?” asked Tom Vance.
Ervin said it is very unlikely the system would plug in the next 10 to 20 years.
Councilmember Nancy Whitten wasn’t fond of the response.
“I’m really puzzled how you can say this an infiltration system and it’s going to last forever,” she said. “This is our drinking source, we want our water source to last as long as our homes last.”
Ervin assured the council the Department of Ecology is filling its legal watchdog role and nothing unsafe will be done.
“I’m not going to ask you to trust me, especially because this might be different from what you heard, but trust Ecolgoy and trust the process,” he said. “This is a very conventional thing that is happening and Ecology has it well in control.”
