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Chevron 4H Shell Mounds


What's New

  • The California State Lands Commission (CSLC), acting as lead CEQA agency for the project, will begin preparation of an Environmental Impact Report (EIR) for the proposed project in the Spring 2013.

  • The CSLC held a public hearing on the Notice of Preparation (NOP) of the EIR for the project on February 7, 2013.

  • The County, as landowner of two of the shell mound sites, former Platforms Hope and Heidi, commented on the NOP to the CSLC in a letter dated January 11, 2013.

  • Description

    The shell mounds are the result of permitted discharges and the shells of former sea life growing on the support legs of 4 former Chevron oil platforms; Hazel, Heidi, Hilda, and Hope. The permitted discharge consisted of drill muds, drill cuttings, and other fluids known to contain chemical contaminants, including metals, petroleum-derived hydrocarbons, and polychlorinated biphenyls (PCBs). These discharges make up the interior of the mounds with the shell material providing a cap like cover. The mounds range from 25 to 28 feet in height and 200 to 250 feet in diameter. The former Platform Hazel site also contains four buried 27 foot in diameter caisson legs. The platforms were decommissioned and removed in 1996. The CSLC oil and gas lease and the California Coastal Commission (CCC) coastal development permit require full removal of the shell mounds, that the sites be free of debris and trawlable with standard trawling equipment, trawl tests have shown the mounds are not trawlable in their current configuration. Two of the shell mound sites are located on County granted lands, former Platforms Hope and Heidi.

    The proposed project submitted to the CSLC by Chevron consists of the following:

  • Quitclaim Chevron’s interest in State Oil and Gas Leases PRC 1824 and PRC 3150, the former sites of Platforms Hazel, Hilda, Hope and Heidi, known collectively as the “4H Platforms”;
  • Leave in place the “shell mounds” and embedded Hazel caisson remnants that remain on the seafloor at the former 4H Platform sites;
  • Enhance Basin 3 in the Carpinteria Salt Marsh by removing the existing sand plug and non-native vegetation; and
  • Provide funds for additional future marsh and/or coastal habitat improvements (or other conservation purposes).
  • The EIR will also analyze alternatives to the proposed project including removal of the shell mounds, leveling and spreading the mounds on the bottom, capping the mounds in place with sand, enhancing the mounds as artificial reefs, and or others as identified during the environmental review process.

    The proposed enhancement of the Carpinteria Salt Marsh is Phase 3 of the Carpinteria Salt Marsh Enhancement Plan initiated by the Santa Barbara County Flood Control and Water Conservation District. The project was analyzed in the Carpinteria Salt Marsh Enhancement Plan Final EIR (SCH No. 2003021016); the EIR can be reviewed on the County Public Works Web site here.


    The shell mounds are located off the coast of Carpinteria and Summerland; the Platforms Hilda and Hazel sites approximately 1.5 miles offshore of Summerland and the Platforms Hope and Heidi approximately 2.5 miles offshore of Carpinteria.

    Past Activities

    The platforms were removed in 1996. CSLC prepared a draft EIR and environmental assessment in 2003 and based on agency and public input determined the feasibility of removal of the shell mounds required more analysis. Additional technical studies, analysis, and discussions were completed by CSLC between 2004 and 2012.

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