MORGAN HILL
– Claims that all perchlorate-contaminated water flowed only
southeast from the Olin Corp. site on Tennant Avenue were
overstated, according to a report last week to the Central Coast
Regional Water Quality Control Board.
MORGAN HILL – Claims that all perchlorate-contaminated water flowed only southeast from the Olin Corp. site on Tennant Avenue were overstated, according to a report last week to the Central Coast Regional Water Quality Control Board.
According to the Olin Corp. report to the Regional Board for the third quarter – the board is the lead agency in the perchlorate investigation and cleanup effort – the chemical can migrate north in some gradients or sections after all.
Groundwater is not captured in a single underground pool but is distributed in several reservoirs at different levels going in, apparently, different directions for a host of reasons.
This came as good news to the city, which has been dealing, without any help from Olin Corp., with perchlorate in several municipal wells northeast of the Olin site.
City Manager Ed Tewes said he was encouraged by the report, given its possible positive affect on the city treasury.
“Before, Olin was insisting that the water moved south,” Tewes said.
The company’s investigation of a potential northerly flow was based on merely “asking around for other people’s data,” he said.
“We weren’t convinced that their prior plans were going to lead to anything since they weren’t going to involve any actual testing,” Tewes said.
The situation has changed with the new report.
“We hope this leads to further discussions about Olin’s obligations to pay the city for costs we’ve had in dealing with the problem,” said Helene Leichter, city attorney. “The (Santa Clara Valley) Water District, too, deserves to be reimbursed.”
Rosemary Kamei, Morgan Hill’s representative on the SCVWD board of directors, said Friday she hadn’t yet heard of Olin’s findings but would find it positive.
“That is good news,” said Kamei.
A series of monitoring wells has been drilled on the Olin site to discover what exactly is going on underground.
The Olin report, submitted to the Regional Board in San Luis Obispo on Thursday, said that during the months of July and August the shallow zone (25.05 to 28.78 feet) flow moved east-northeast, though southeast in September.
The intermediate zone was monitored at three levels: at 89 to 99 feet water flowed northeast in July, east in August and southeast in September. At the 134-to-142-foot depth, water flowed east in July, southeast in August and east-southeast in September. At the 175-to-195-foot level water moved northeast in July, north in August and south-southwest in September.
The deep zone monitoring discovered water moving southwest in all three months at 200-to-210-foot depths and, at 313-to-341-foot depths moving northeast in July, August and September. Testing was done by MACTEC Engineering and Consulting.
Tewes said Olin had apparently had the data claiming a northeasterly run for some time but its two consultants had not shared the information with each other or with others at Olin.
Representatives of Olin Corp. did not return phone calls on Monday.
The water district had loaned the city about $130,000 to install an ion-exchange perchlorate treatment plant on its Nordstrom well, at Murphy Road and East Dunne Avenue, since Olin had, so far, refused to pay. With the Nordstrom and four other city wells off line, water supplies had been stressed during recent hot weather peak times.
Harvey Packard, senior water resources engineer for the Regional Board, said he was being cautious about the meaning of the Olin report.
“This is not proof,” said Packard. “It is only two sampling events where a very small area shows this gradient.”
Packard said the Regional Board would be looking for data to prove or disprove the third quarter report data.
“It will probably affect how we view Olin’s recent work plan for investigating the area,” Packard said. “It may warrant more field work to verify the data in the monitoring report.”
Olin Corp. and Standard Fusee Corp. had manufactured safety road flares at a plant on Tennant and Railroad avenues for 40 years, until the plant was closed and demolished in 1997. The perchlorate leached into the underground aquifer from a pond on the plant site into which product residue was routinely washed. The practice was not illegal at the time.
It was discovered in January that the chemical, which may cause thyroid dysfunction in humans and animals, had infiltrated wells in southeast Morgan Hill, San Martin and a few in north Gilroy.
