Storm water system concerns addressed

June 4, 2013

By Peter Clark

Issaquah’s side in a contentious storm water debate was delivered in the May 20 regular City Council meeting.

In his presentation, RH2 Consultant Dan Ervin answered recent claims that the city aims to pollute the groundwater aquifer through a storm water runoff system. He gave the council a comprehensive description of the history of the Lower Reid Infiltration Gallery and the process the storm water goes through as it is drained into the lower Issaquah Valley aquifer.

Ervin detailed how resuming infiltration into the aquifer would be the continuation of state Department of Ecology monitoring that falls in line with all of the regulations necessitated by the department’s standards.

The Sammamish Sewer and Water District has said the Department of Ecology’s imminent reauthorization of the city to infiltrate storm water from the Issaquah Highlands into the aquifer below would mean adding heavy metals and fecal coliform into the district’s resource wells.

Ervin said the infiltration gallery, originally built in 1964 and purchased by developer Port Blakely along with the land that would become the highlands, was designed to withstand the runoff that would come with building out the land.

“There was every reason to believe that this was an area that had the ability to assimilate lots of dirty storm water,” Ervin said. He then explained official hesitation about the quantity and quality of storm water infiltrated into the ground, which ultimately led to a termination of the infiltration gallery’s operation. “The Department of Ecology became concerned about the ability of the vadose zone to remove contaminants. So, they began intensive and extensive monitoring to measure storm water and groundwater.”

A vadose zone is the layer of sand and soil that filters out contaminants as gravity takes water through it.

He said that after years of monitoring the groundwater in the aquifer, the Department of Ecology wanted to continue operation and testing with reduced input from the infiltration gallery.

“What’s going to happen next is not that we will begin operating the gallery. What’s next is that we enter the second phase of monitoring. We will infiltrate water and monitor the vadose zone and its ability to remove contaminants,” Ervin said, adding that the Department of Ecology and RH2 believe that the water will be suitable to enter the aquifer. “This will simply be another monitoring phase where we check to see if our assumptions of the vadose zone are accurate. If not, we will be asked for further treatment or to stop infiltration.”

Only Council President Fred Butler made any statement after Ervin finished his presentation.

“We’re working closely with the Department of Ecology and they’re the ones really driving the train on this,” Butler said. “This is based on rigid requirements and standards that either it works or it doesn’t work.”

Gail Twelves, a marketing consultant working with the Sammamish Sewer and Water District, raised some objections about Ervin’s presentation. She said that he misrepresented the threat to drinking water provided by the district. She said that the urban water is very different from construction waste and that it was the fecal coliform that shut down the infiltration gallery, which she believed Ervin downplayed in his presentation.

Additionally, she said that the city’s relationship with the Department of Ecology might not be as solid as he described.

“In fact, it took more than a year to get a meeting with Ecology to present the scientific facts that demonstrate the high risk of resuming injection,” she wrote in an email circulated to the press. “If fecal coliform entered the aquifer before, it’s highly likely it will again.”

Ervin finished his delivery to the council by saying that it is the state government’s responsibility to ultimately oversee the environmental impact.

“What’s important to remember is that the Department of Ecology is a partner in this process and legally obligated to perform this watchdog role,” Ervin said. “We’ve had to comply with standards that are higher than any other municipality, and there isn’t any reason that they won’t be successful in their due diligence.”





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