Site Access for Phase II Subsurface Investigation by Partner ESI at Marine Group Boat Works Facility and on District Tidelands

Site Access for Phase II Subsurface Investigation by Partner ESI at Marine Group Boat Works Facility and on District Tidelands

The proposed project would allow for a Phase II Subsurface Investigation by Partner Engineering and Science, Inc. (Licensee), as contracted by Marine Group Boat Works, LLC (Tenant), in the city of Chula Vista, California. Activities associated with the investigation would include, but not be limited to, a geographical survey and sample borings to help evaluate the potential impact of petroleum hydrocarbons, volatile organic compounds (VOCs), PCBs, and/or metals to soil, sediment, groundwater, and/or soil gas as a consequence of a release, or releases, from the on-site activities and known off-site impacts. Additionally, the proposed project would include polycyclic aromatic hydrocarbon (PAH) analysis, as PAHs have been previously identified as a contaminant in the Tenant and surrounding parcels. Sample borings would be collected to facilitate the collection and analysis of soil, groundwater, and/or soil gas samples, and the collection of one (1) offshore sediment sample. Boring placement is proposed at three (3) primary areas of concern throughout the proposed project site, which would include locations on both the Tenant leasehold and the adjacent marshland on San Diego Unified District (District) property: • The hazardous material storage area (Tenant leasehold) • The stormwater ponds/containment area (Tenant leasehold) • Along the southern and eastern boundary of the property (District Tidelands) Approximately twelve (12) subsurface borings would be carried out across the locations listed above, which would consist of the following at each respective location: • Four (4) borings to a depth of up to approximately ten (10) feet below ground surface (bgs) • Three (3) borings to a depth of up to approximately five (5) feet bgs • Five (5) borings to a depth of up to approximately five (5) feet bgs The proposed project is anticipated to occur in Spring 2025 and would take approximately one (1) month to complete. Work to collect the sample borings would take up to two (2) days, and would be performed during the normal work hours of approximately 7:00 a.m. to 5:00 p.m. Boring placement may be modified as necessary. Borings would be drilled using hand tools, such as hand augers, and direct-push technology, such as a truck-mounted drill rig; no additional special equipment would be required for the proposed project. Borings would be backfilled with bentonite to the surface and capped with concrete, asphalt, and/or soil to match the surrounding ground cover. Sampling procedures would generally conform to the requirements of the SWRCB, the Department of Toxic Substances Control, the San Diego County Department of Environmental Health and Quality (DEHQ), and the United States Environmental Protection Agency. A completed application and site plan would be submitted for review and approval of the necessary Boring Permit from the DEHQ. Due to the proposed project's occurrence within the bird breeding and nesting season (February 15-September 15), a nesting bird survey was conducted on May 21, 2025, in which all habitat areas east of the Tenant leasehold were surveyed. Surveyors identified three (3) species transiting the area: • Song sparrow (Melospiza melodia) • House finch (Haemorhous mexicanus) • Common yellowthroat (Geothlypis trichas) Two (2) common yellowthroat nests were identified in the nearby coyote bush, approximately 60 feet from the easternmost proposed boring location, approximately 100 feet from the northernmost location, and approximately 300 feet from the westernmost. No special status species were seen during the survey. To avoid any impacts on the identified nests, new boring locations shall be selected so there are no nests within 300 feet. If equipment is limited to hand augers, the distance may be reduced following discussions with the District. It is recommended the equipment used at the boring locations east of the Tenant leasehold be limited to hand augers, rather than a truck-mounted drill rig. Additionally, personnel should avoid walking through the dense habitat and stay on the existing footpaths throughout the project site. The proposed project would also include issuance of a Right of Entry (ROE) to allow the Licensee to enter the project site on the Tenant leasehold, as well as the three (3) locations adjacent to the Tenant leasehold on District Tidelands. The area proposed for use under this ROE would be used by the Licensee and their authorized agent(s) and contractor(s) for the sole purpose of clearing boreholes of utility lines through a geophysical survey, drilling three (3) borings at locations outside of the Tenant leasehold, as well as the ingress and egress in support of these activities. It is anticipated that the ROE would have a total term of approximately one (1) month, or upon completion of the work, whichever occurs earlier. The ROE may be terminated by the District as a matter of right and without cause at any time upon providing twenty-four (24) hours written notice to the Licensee of such termination. Due to its nature and limited scope, construction of the proposed project would generate a minor amount of vehicle trips and would require limited use of equipment. Therefore, impacts related to air quality, greenhouse gas emissions, and transportation and traffic are not anticipated to occur. Furthermore, the Licensee would be responsible for complying with all applicable federal, state, and local laws regarding construction demolition debris, hazards and hazardous materials, and stormwater.

Chula Vista

San Diego

Southern California

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