Adanta, Inc. took the lead in executing a soil removal operation on behalf of the National Park Service (NPS) to address hydrocarbon-contaminated soil at the former Above Ground Storage Tank (AGST) Site within Fort Baker Building 637, a vital part of the Bay Area Discovery Museum (BADM) located in the Golden Gate National Recreation Area (GGNRA). Serving as the prime contractor, Adanta collaborated with Innovative Construction Solutions (ICS) as a subcontractor.
Our main goal was to excavate contaminated soil, replace it with clean fill, and conduct exit (confirmation) soil sampling to ensure compliance with regulatory cleanup levels mandated by the Base Realignment and Closure Act of 1990 (BRAC) after the removal of contaminated soil.
In our capacity as the prime contractor, Adanta developed crucial planning documents for site assessment activities. These included a Work Plan, Traffic Management Plan, Stormwater Pollution Prevention Plan (SWPP), and Health and Safety Plan (HASP) for the soil removal action and sampling at the site.
The site assessment field work, conducted in August 2021, encompassed several key activities:
1. Utility Survey and Clearance: Ensuring investigation locations did not interfere with subsurface utilities.
2. Installation of Temporary Infrastructure: This included fencing, work areas, bin staging areas, and straw wattles to maintain site cleanliness.
3. Soil Excavation: Using the “ABC” slot trenching method, we reached a depth of 7 feet below ground surface (bgs), resulting in the removal of approximately 81 cubic yards of contaminated soil.
4. Backfilling of Trenches: This involved the use of controlled density fill (CDF)/cement slurry and subsequent curing.
5. Exit Soil Sampling: Collection of samples to confirm the successful removal of impacted soil.
6. Clean Fill Placement: Followed by compaction to the prescribed density.
Adanta effectively managed waste disposal in compliance with regulatory standards, handling approximately 81 cubic yards of excavated soil and concrete debris from the concrete pad demolition. All soil and groundwater sampling and analytical reporting adhered to the State of California Underground Storage Tank Regulations and Local Implementing Agency requirements.
To document the comprehensive field activities, methods, and procedures used for the hydrocarbon-contaminated soil removal at Fort Baker Building 637 (Site), Adanta prepared a detailed Removal Action Report. The remedial actions successfully eliminated soil contamination risks to human health and the environment, as validated by exit sampling results. The Removal Action Report received final approval, confirming the successful accomplishment of the project’s goals.
