SCH Number 2023110376

Project Info

Title

Cal Lease Soil Remediation Project

Description

The project is for a Land Use Permit to implement the actions described in the Remedial Action Work Plan dated July 2021, in parts of the CAL Lease in the North Cat Canyon Oil Field. The site contains inactive and abandoned oil wells and associated well pads but is currently used for cattle grazing and cultivation of hay and vineyards. Site investigations between 2000 and 2020 identified elevated concentrations of total petroleum hydrocarbons (TPH) and associated volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) in approximately 4,926 cubic yards soil and perched water surrounding former diluent pipelines in three areas: A5-01, B5-02/B5-03, and B6-03. The project proposes excavation and disposal of approximately 4,306 cubic yards of impacted soil with constituents of potential concern (COPCs) at these three locations, confirmation soil sampling to confirm achievement of the site-specific cleanup goals, backfilling of the excavation areas with approximately 4,306 cubic yards (cy) of imported clean fill, and restoration of the disturbed areas. Excavated soil will be stockpiled on plastic sheeting in the staging areas until disposal offsite. Three tree exclusion zones (TEZ-1, TEZ-2, and TEZ-3) and two depth exclusion zones (DEZ-1 and DEZ-2) are proposed to protect the riparian and oak tree habitat and reduce excavation instability. The impacted soil to be left in the exclusion zones place will be managed beneath a cover of clean fill and native vegetation. Temporary erosion and sediment controls will be installed and maintained during earth disturbance activities. Once the excavations are backfilled with clean earth material, well pads associated with previously abandoned wells 40, 50, and 89 and all disturbed areas will be recontoured to resemble the natural topography and erosion and sediment controls will be applied to the ground surface, including hydromulch and dispersal of native seeds. Dewatering activities may also be conducted if perched groundwater is encountered in the excavations. Additionally, at least one groundwater monitoring well will be installed at each of the three remediation areas between 7.5 and 33 feet deep to monitor constituents are stable or decreasing. Once groundwater monitoring is complete, the wells will be abandoned. Existing oil field roads and historical well pads within the CAL Lease and adjacent United California Lease (UCAL Lease) will be used as access to the work areas and for temporary staging and stockpiling of equipment and materials. Approximately 2.59 acres of previously developed areas will be used for equipment storage and soil stockpile at locations 1, 2, 3, 4, 5, 6, and 7. Approximately 200 truck trips are expected to be made for export soil and 200 truck trips for import soil. There would be an average of about 10 truck trips per day, with a peak of about 50 truck trips per day. Grading includes approximately 9,598 cy of cut and fill material. The export material would be disposed of as Non-Hazardous Hydrocarbon Impacted Soil at the Santa Maria Regional Landfill, approximately 10 miles north. The property is a 537.84-acre parcel zoned AG-II-100 and shown as Assessor's Parcel Numbers 129-180-018 & 129-180-038, Santa Maria Valley Area, Fourth Supervisorial District.

2 documents in project