Beale Air force Base, Capehart Service Station, Marysville, CA
Civil-Environmental Engineering
Leaking Underground Storage Tank, Fractured Bedrock Analysis, Remediation Services.
Project Description:

Support facilities to maintain the mission at Beale AFB have required them to store and use various fuels and chemicals. At the Capehart Service Station, several USTís were removed and found to have leaked petroleum hydrocarbons containing high levels of MTBE into the surrounding subsurface.

 

The site is located in the foothills of the Sierra Nevada Mountain Range, and dense steeply dipping fractured bedrock was found to have provided complex pathways for the migration of contaminants. H&A evaluated the site geology and formulated a site-specific approach to investigate this migration in two phases:

 

Groundwater Remediation System

Following the initial site investigation, H&A designed and installed a groundwater extraction and treatment system to remediate perched groundwater located within the former UST pit. Two extraction wells were fitted with Grunfos RediFlow 3 submersible pumps that remove contaminants into two 1000-pound Granular Activated Carbon canisters and a 200-pound fine-grained carbon canister which discharge treated groundwater to the sanitary sewer system. H&Aís quick design and implementation of the groundwater remediation system allowed Beale AFB to meet all regulatory requirements while maintaining the ongoing Base mission without imposed fines or notices of violation.

 

Fractured Bedrock Aquifer Analysis

Air and mud rotary drilling technologies were used to collect continuous rock cores, advance exploratory borings, and install groundwater monitoring wells to depths as great as 100 feet in the meta-volcanic rock. Using innovative techniques and applied sciences, Beale AFB Capehart Service Station, Rock Coringsuch geophysical technologies as downhole optical televiewer and acoustic televiewer image surveys were performed to measure orientation and degrees of fractures and bedding planes. Heat-pulse flow meter testing was performed within the open boreholes to isolate fractures with flowing groundwater. H&A is continually detailing the site conceptual model to determine fractures zones preferential pathways for MTBE migration, and develop an appropriate remedial action for the fractured bedrock aquifer to prevent degradation to the environment and protect human health.

 

For more on fractured rock and the status of this site visit www.clu-in.org/fracrock, choose View Site Profile, and then select Beale AFB.