MIDDLETOWN >> Nearly two decades after halting operations on its geo-thermal wells a utility devoted
to watch of red alerts, thanks to reliable infrastructure, fulfills the promise of a good corporate neighbor.
Pacific Gas & Electric utility doing community outreach in the Rio Rancho area of Middletown, Lake County dispatched a trio of staffers from Environmental Remediation Department, Caitlin Gorman, Ken Simas and Tracy Crcic to the monthly Middletown Area Town Hall meeting at the city Senior Center to inform MATH regulars of tree removal and other trees service as well as systems follow up for the Rio Rancho Area, Gorman informed audience members. The site along Butts Canyon Road near Freeman Lake is the subject of ongoing investigations of landfill. In 1986 PG&E shuttered the wells, which is where contaminated materials originated from. In 2006, PG&E wrapped up closure by consolidating material from five ponds into one and keeping the liquid material from reaching the Lake with an impermeable cap, and underneath an impermeable layer that prevents anything from infiltrating the lake.
“There are contaminants of concern out there,” Gorman informed the audience. “Salts from the drilling mud still cuttings, boron, chloride and sulfates, material remaining from prior operations,” Gorman said. Since that time, they’ve been doing monitoring, maintenance and additional studies, where tree plantations have been impacted and tree removal as well as systems follow up are planned along with implementing a method of how to keep the groundwater from interacting with the lake whether the groundwater is moving or not. “These pictures show the site is surrounded on three sides of Eucalyptus, Gorman said. “Eucalyptus was implanted to hopefully to draw down the groundwater table and does a great job in summer. We sample surface and groundwater in October and April, when monitored for water quality, then map the concentrations and elevations to see there’s no migration away from the site.” On another slide, Gorman showed a plume map (contaminated groundwater) ‘And these pictures show three sides of Eucalyptus plantations and what the plan is for those,” Gorman said. Then they map the concentrations and elevations to see that there’s no migration away from the site for contamination.
“We can drop the water table to prevent groundwater from interacting with the lake and do groundwater pumping tests in the fall and if that’s successful, looks like it will work, we might install a larger scale system,” Gorman said. “The biggest project for 2024 is removing the Eucalyptus tree plantations. They were intended to drop the groundwater table, but in summer the groundwater table dropped so low the eucalyptus had to be irrigated to survive. We decided to take them out and the water board agreed.
But an audience member asked if they lowered the water table too much would they not draw back the aquifer into the contaminated area? But Gorman reassured their consultants were already investigating that aspect. “I think our wells are shallow enough that they could be that impacted. Still, an audience member claimed the local aquifer was no more than 50 feet. Yet project manager Simas saids that was in part the reason for a pilot study to determine the impact on the aquifer and there was no reason not to do a draw on the aquifer.
Still another inquired why not tests were done on arsenic. Project manager Simas noted the constituent contaminant materials identified by the Water Board did not identified arsenic yet only boron, salts, chloride and the like. The question also arose of what was the difference between contaminants making up the plume and the waste. Simas noted the waste is the physical solid land fill material, while the plume is the groundwater impacted by the contaminants such as boron, chloride, sulfates and salts. He also explained they have three sets of monitor wells. One is alluvium, loose clay, silt, sand or gravel, but not solid rock, deposited in estuaries, lakes or ponds, and that there is another well located well below that, a sandstone and still deeper than that, one made of fractured bedrock.
Gorman noted the Water Board does not consider the above landfills a hazardous waste facility. “It may have things you don’t want in drinking water, but as long as there is a plume, were obligated to monitor that plume and make sure its not expanding or migrating,” she said. “For the last year and a half it has been where it was since we started monitoring, so it’s not a dynamic situation. We do want to keep it contained and if possible, reduce it where we can.”
