NHIS: Non-Hazardous Hydrocarbon Impacted Soil Program

A flare is used to burn the landfill gas into much more environmentally friendly components.


The Santa Maria Regional Landfill is strictly regulated by various regulatory agencies but falls mainly under the oversight of the following four agencies:

  • California Integrated Waste Management Board (CIWMB)
  • Santa Barbara County Public Health Department, Environmental Health Services (SBCEHS)
  • Central Coast Regional Water Quality Control Board (CCRWQCB)
  • Santa Barbara County Air Pollution Control District (SBCAPCD)

Each of these agencies oversees that the landfill is in compliance with regulations and the environment is protected, by ensuring that monitoring systems are in place. The Santa Maria Regional Landfill monitoring systems include surface water sampling, groundwater sampling, air monitoring, subsurface gas migration monitoring, and a load checking program. The groundwater and air monitoring systems will continue to be monitored for at least 30 years after the landfill reaches capacity and is closed.

Twenty-five groundwater wells are placed strategically around the landfill. These groundwater wells are monitored every quarter to ensure that the ongoing landfill operations are not impacting the groundwater. This monitoring also serves as early warning, should groundwater impacts be detected, as they were in the mid-1990s. In addition, the surface waters are sampled during rainstorms to ensure that the runoff is appropriate for discharge. All sampling results are forwarded to the appropriate regulatory agency.

A gas collection system is employed to handle landfill gas generated from the decomposition of buried refuse. This gas consists primarily of methane and carbon dioxide—both greenhouse gases. A flare is used to burn off these gasses and convert them into more environmentally-friendly components. Eventually the landfill gas will be piped to Marian Hospital and used to generate electricity. The landfill gas collection system consists of 50 vertical and 3 horizontal extraction wells. The primary objectives for the landfill gas control/recovery system at the site are to:

  • Control lateral migration of methane at the property boundary of the landfill.
  • Control the source of landfill gas-related groundwater contamination.
  • Control surface emissions of LFG.

Twenty-six soil gas monitoring probes were constructed around the landfill to ensure that offsite subsurface landfill gas migration is not occurring. Each of these probes has two sampling points: one for the deep, and one for the shallow region, which are measured quarterly. All sampling results and operational records are forwarded in reports submitted to the appropriate regulatory agency for review.

This map of the Santa Maria Regional Landfill shows its closed and active areas, wells and monitoring locations.

cogeneration facility

A Cogeneration Facility at the City’s Wastewater Treatment Plant. A similar facility will be built to supply Marian Medical Center with electricity using landfill gas.