Who oversees PG&E’s work at this site?
The Water Board, part of the California Environmental Protection Agency, is the regulatory agency responsible for overseeing and approving the work. Some work also requires permits from other agencies, including Lake County, the US Army Corps of Engineers, and the California Department of Fish and Wildlife.
What chemicals were found in the soil and groundwater?
Waste in the landfill contains drilling muds, construction debris, sulfur compounds from geothermal energy production, and naturally-occurring mineral compounds and elements from the surrounding region. Elevated concentrations of total dissolved solids, chloride, boron, and sulfate are present in the groundwater in the vicinity of the landfill. Testing has determined that the geothermal waste material in the landfill is not hazardous. This has been confirmed by the Water Board. The groundwater impacts are confined to the property and the impacted groundwater has remained stable since groundwater monitoring at the site began in the early 1990s. Why did PG&E choose to consolidate and cap the wastes as opposed to removing them?
An evaluation of cleanup alternatives was performed that was based on a prescribed list of factors including effectiveness, feasibility, regulatory and public acceptance, overall protection of human health and the environment, and cost. Based on this evaluation, the Water Board determined that consolidating and capping the wastes on-site was the best cleanup alternative. Has PG&E completed the closure of the landfill?
PG&E has achieved all the requirements of the Water Board’s remedy for the closure of the landfill except the required year-round separation between the groundwater and landfill waste. Separation has been achieved during most of the year for the entire landfill; however, there are currently limited areas of the landfill where separation is not achieved during part of the year. PG&E is currently engaged in further studies and conversations with the Water Board to determine whether separation can be achieved. If the Water Board determines that additional remediation or closure activities are necessary, PG&E will then inform the community. Can surface water or groundwater impacted by the site spread to my property or impacted groundwater in the area outside the property?
PG&E has a robust groundwater monitoring well network and performs surface- and groundwater monitoring on a semi-annual basis and the results are submitted to the Water Board. Since 1992 monitoring results indicate that surface- and groundwater have not impacted neighboring properties. In addition, results indicate the area of impacted groundwater remains stable, on-site, and has not moved for over two decades. PG&E will continue to conduct semi-annual surface- and groundwater monitoring and report these results to the Water Board, which is consistent with the agency’s monitoring plan for the Site.Why do I see PG&E crews at the former landfill?
PG&E regularly monitors and maintains the landfill, tree plantations, and the property to ensure the effectiveness of the landfill closure and to implement the fire prevention plan for the Site. PG&E also conducts semi-annual monitoring of the surface and groundwater conditions.What would happen if there was a fire and the tree plantations burned?
PG&E has a robust fire prevention program that includes annual goat grazing and brush clearing to reduce fire hazards, maintenance of the tree plantations, maintenance of the on-site fire suppression facilities and water supplies, and maintenance of a network of roads and turnouts throughout the Site to facilitate access and segregate the tree plantation stands. While a major tree plantation fire is unlikely, if they were to burn in a fire to the point where they could not recover, PG&E would actively work with the Water Board to develop a replacement program to maintain groundwater levels.What would happen to the landfill in an earthquake?
The landfill was designed to withstand an earthquake and the mixed waste and clean soil is firm enough that it is not expected to be damaged. The landfill would be inspected following significant earthquakes and any settlement repaired.