For purposes of this article, the following definitions apply:

(a) “Active life of the facility” means that period of time when the facility has the potential to adversely affect the waters of the state, but if the owner enters into an agreement with the board to properly close the impoundment on a specified date, the active life of the facility means that period of time up to that specified date.

(b) “Background water quality” means the level of concentration of indicator parameters in groundwater that is not, or has not been, affected by any hazardous waste, hazardous waste constituent, or hazardous waste leachate emanating from a particular waste management unit.

(c) “Board” or “state board” means the State Water Resources Control Board.

(d) “Close the impoundment” means the permanent termination of all hazardous waste discharge operations at a waste management unit and any operations necessary to prepare that waste management unit for postclosure maintenance that are conducted pursuant to the federal Resource Conservation and Recovery Act of 1976 (42 U.S.C. Sec. 6901 et seq.), and the regulations adopted by the state board and the department concerning the closure of surface impoundments.

(e) “Constituent” means an element, chemical compound, or mixture of compounds that is a component of a hazardous waste or leachate and has the physical or chemical properties that cause the waste to be identified as hazardous waste by the department.

(f) “Discharge” means to place, dispose of, or store liquid hazardous wastes or hazardous wastes containing free liquids into or in a surface impoundment owned or operated by the person who is conducting the placing, disposal, or storage.

(g) “Emergency containment dike” means a berm that is located around a tank solely for the purpose of containing any emergency spills from the tank and does not contain any liquid hazardous waste or hazardous wastes containing free liquids for longer than 48 hours.

(h) “Facility” means the structures, appurtenances, and improvements on the land, and all contiguous land, that are used for treating, storing, or disposing of hazardous waste. A facility may consist of several waste management units.

(i) “Free liquids” means liquids that readily separate from the solid portion of a hazardous waste under ambient temperature and pressure.

(j) “Groundwater” means water below the land surface in a zone of saturation.

(k) “Hazardous waste” means a waste that is a hazardous waste, as specified in this chapter.

(l) “Indicator parameters” means the measureable physical or chemical characteristics in groundwater or soil-pore moisture that are likely to be affected by hazardous waste disposal operations and are used, for comparison purposes, to assess the result of hazardous waste disposal operations at a particular waste management unit on the waters of the state.

(m) “Landfill” means a facility or part of a facility where hazardous waste is placed in or on land for disposal and that is not a land farm, surface impoundment, or an injection well.

(n) “Leachate” means any fluid, including any constituents in the liquid, that has percolated through, migrated from, or drained from, a hazardous waste management unit.

(o) “Owner” means a person who owns a facility or part of a facility.

(p) “Perched water” means a localized body of groundwater that overlies, and is hydraulically separated from, an underlying body of groundwater.

(q) “pH” means a measure of a sample’s acidity expressed as a negative logarithm of the hydrogen ion concentration.

(r) “Pile” means any noncontainerized accumulation of solid, nonflowing hazardous waste that is used for the purpose of treatment or storage.

(s) “Pollution” has the same meaning as defined in Section 13050 of the Water Code.

(t) “Potential source of drinking water” means either water that is identified or designated in a water quality control plan adopted by a regional board as being suitable for domestic or municipal uses and is potable, or water that is located in water-bearing strata, is an underground source of drinking water, as defined in Section 146.3 of Title 40 of the Code of Federal Regulations, and does not meet the criteria for an exempted aquifer, pursuant to Section 146.4 of Title 40 of the Code of Federal Regulations.

(u) “Qualified person” means a person who has at least five years of full-time experience in hydrogeology and who is a certified engineering geologist certified pursuant to Section 7842 of the Business and Professions Code, a professional geologist registered pursuant to Section 7850 of the Business and Professions Code, or a registered civil engineer registered pursuant to Section 6762 of the Business and Professions Code. “Full-time experience” in hydrogeology may include a combination of postgraduate studies in hydrogeology and work experience, with each year of postgraduate work counted as one year of full-time work experience, except that not more than three years of postgraduate studies may be counted as full-time experience.

(v) “Regional board” means the California regional water quality control board for the region in which the surface impoundment is located.

(w) “Report” means the hydrogeological assessment report specified in Section 25208.8.

(x) “Surface impoundment” or “impoundment” means a waste management unit or part of a waste management unit that is a natural topographic depression, artificial excavation, or diked area formed primarily of earthen materials, although it may be lined with artificial materials, that is designed to hold an accumulation of liquid hazardous wastes or hazardous wastes containing free liquids, including, but not limited to, holding, storage, settling, or aeration pits, evaporation ponds, percolation ponds, other ponds, and lagoons. Surface impoundment does not include a landfill, a land farm, a pile, an emergency containment dike, a tank, or an injection well.

(y) “Tank” means a stationary device, designed to contain an accumulation of hazardous waste, that is constructed primarily of nonearthen materials, such as fiberglass, steel, or plastic to provide structural support, and has been issued a permit pursuant to Section 25284.

(z) “Vadose zone” means the zone between the land surface and the water table.

(aa) “Waste management unit” means that portion of a facility used for the discharge of hazardous waste into or onto land, including all containment and monitoring equipment associated with that portion of the facility.

(Amended by Stats. 2006, Ch. 538, Sec. 381. Effective January 1, 2007.)