WatchSonoma Watch

PG&E may scale back plan to protect Prince Memorial Greenway in Santa Rosa from toxic sludge


The Pacific Gas & Electric Co. is rethinking how to best prevent contamination from a downtown property from migrating toward Santa Rosa Creek, representatives told the City Council on Tuesday.

The utility, which has been working for years to clean up toxic material at the site of its former manufactured-gas plant on First Street, previously has proposed building a 300-foot-long cutoff wall that would funnel and treat any contaminated groundwater from the property.

A portion of Santa Rosa's Prince Memorial Greenway had been closed at nights since May 28 for PG&E to perform a toxic cleanup.

A portion of Santa Rosa’s Prince Memorial Greenway had been closed at nights since May 28 for PG&E to perform a toxic cleanup.

But after analyzing the plan further, the company has realized that the wall would be a long, disruptive and expensive project requiring the rerouting of the creek and dismantling of sections of the Prince Memorial Greenway.

“What we are looking at is identifying other alternatives that would give an equivalent amount of protection, but would not require us to tear up the Prince Memorial Greenway three seasons in a row,” said Max Reyhani, the environmental engineer hired by PG&E to oversee the work.

The firm instead is talking to regulators from the North Coast Water Quality Control Board about possibly constructing two smaller concrete walls that would extend out from either side of an existing retaining wall installed during the construction of the greenway in 2004, Reyhani said.

The idea still is conceptual and has yet to be formally submitted to the water board. But if it is approved, Reyhani said it’s possible the work could be completed in one construction season, which is limited by permitting requirements to June to October.

The City Council asked PG&E officials for a detailed update of the long-term cleanup project so they and the public could gain a better understanding of the history of the site, remediation work that has been to date and issues yet to be resolved.

“There are a lot of people who are very concerned about these issues,” Councilman Jake Ours said. “They’re worried, and that’s not a good thing.”

Waste products from the manufactured-gas process, including lamp black and coal tar, have been found in significant volumes on the site, which also contains leaking underground fuel storage tanks. The plant operated from 1876 to 1924, when PG&E decommissioned it and buried much of the toxic material on the site. The property was later sold to developers, who cleaned up some but not all of it during the construction of a four-story office building and parking lot in 1989.

Even though it no longer owns the property, PG&E has taken financial responsibility for the cleanup and has spent more than $10 million to date because it caused the contamination, officials said.

One significant outstanding issue is how the utility will handle a 10,000-gallon underground steel tank that is filled with coal tar, a thick, black substance with the consistency of taffy, Reyhani said.

Removing the tank or its contents presents a host of challenges. PG&E and its consultants considered heating it up and catching the vapors, much was done for three years on a different area of the property. They’ve also looked into freezing it in place, melting or dissolving the contents and sucking them out, walling it off, or excavating it beneath a huge tent to catch the fumes.

“We’ve looked at everything,” Reyhani said.

All options present challenges because of the site’s proximity to the greenway, a residential neighborhood and multiple downtown businesses and offices, Reyhani said.

PG&E’s preference is to find a way to remove the tank, said Sally Goodwin, a project engineer for the utility.

“To be honest, I’d rather take it out if we could,” Goodwin said.

But the work would take months and the tent that would need to be constructed would need to be four stories high and would take up most of the parking lot, Reyhani said.

“It would be a huge undertaking,” he said.

The reason the company is willing the take the extra time to rethink its options is because the ground in the area of the tank is stable and the contents are not migrating toward the creek, Reyhani said.

Councilwoman Julie Combs sounded skeptical when she asked how the engineers could be sure that a “carcinogenic-taffy-loaded rusty steel tank” didn’t pose a threat to the creek or groundwater.

But officials assured her and the council that the material was not mobile, was safety capped beneath a parking lot for now, and groundwater levels do not currently show significant contamination levels.

You can reach Staff Writer Kevin McCallum at 521-5207 or kevin.mccallum@pressdemocrat.com. On Twitter @citybeater.

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