§ 66265.310. Closure and Postclosure Care.

(a) At final closure of the landfill or upon closure of any cell, the owner or operator shall cover the landfill or cell with a final cover designed and constructed to:

(1) prevent the downward entry of water into the closed landfill throughout a period of at least 100 years;

(2) function with minimum maintenance;

(3) promote drainage and minimize erosion or abrasion of the cover;

(4) accommodate settling and subsidence so that the cover's integrity is maintained;

(5) have a permeability less than the permeability of any bottom liner system or natural subsoils present;

(6) accommodate lateral and vertical shear forces generated by the maximum credible earthquake so that the integrity of the cover is maintained;

(7) preclude ponding of rainfall, surface run-off or run-on over the closed area;

(8) conform to the provisions of subsections (e) through (r) of section 66264.228, except that the Department shall grant a variance from any requirement of subsections (e) through (r) which the owner or operator demonstrates to the satisfaction of the Department is not necessary to protect public health, water quality or other environmental quality.

(b) After final closure, the owner or operator shall comply with all postclosure requirements contained in sections 66265.117 through 66265.120 including maintenance and monitoring throughout the postclosure care period. The owner or operator shall:

(1) close the facility in a manner that will minimize any chance of postclosure release of hazardous waste or discarded hazardous material; facilitate postclosure maintenance, monitoring and emergency response; and require minimum maintenance of containment structures, leachate collection systems and surface drainage collection or diversion systems;

(2) maintain the integrity and effectiveness of the final cover, including making repairs to the cover as necessary to correct the effects of settling, subsidence, erosion or other events;

(3) maintain and monitor the groundwater monitoring system and comply with all other applicable requirements of article 6 of chapter 14;

(4) prevent run-on and run-off from eroding or otherwise damaging the final cover;

(5) protect and maintain surveyed benchmarks used in complying with section 66265.309; and

(6) maintain and monitor the leak detection system in accordance with Sections 66264.301(c)(3)(D) and (c)(4) of this chapter and 66265.304(b), and comply with all other applicable leak detection system requirements of this part;

(c) If liquid has been disposed of at the site in containers, in bulk or in a moist semisolid that will drain when the weight of overburden is applied, the owner or operator shall do one of the following before closing the facility:

(1) demonstrate to the satisfaction of the department that incompatible wastes do not commingle and that nongaseous constituents of waste cannot migrate from the site; or

(2) provide measures to prevent incompatible waste from mixing after closure and to prevent migration of nongaseous waste constituents from the site after closure.

(d) The owner or operator shall consider at least the following factors in addressing the closure and postclosure care objectives of subsection (a) of this section:

(1) type and amount of hazardous waste and hazardous waste constituents in the landfill;

(2) the mobility and the expected rate of migration of the hazardous waste and hazardous waste constituents;

(3) site location, topography and surrounding land use, with respect to the potential effects of pollutant migration (e.g., proximity to groundwater, surface water and drinking water sources);

(4) climate, including amount, frequency and pH of precipitation;

(5) characteristics of the cover, including material, final surface contours, thickness, porosity and permeability, slope, length of run of slope and type of vegetation on the cover; and

(6) geological and soil profiles and surface and subsurface hydrology of the site.

(e) In addition to the requirements of section 66265.117, during the postclosure care period, the owner or operator of a hazardous waste landfill shall:

(1) maintain the function and integrity of the final cover as specified in the approved closure plan;

(2) maintain and monitor the leachate collection, removal and treatment system (if there is one present in the landfill) to prevent excess accumulation of leachate in the system;

(3) maintain and monitor the gas collection and control system (if there is one present in the landfill) to control the vertical and horizontal escape of gases;

(4) protect and maintain surveyed benchmarks; and

(5) restrict access to the landfill as appropriate for its postclosure use.

HISTORY

1. New section filed 5-24-91; operative 7-1-91 (Register 91, No. 22).

2. Amendment of subsections (b)(4)-(5), new subsection (b)(6) and amendment of Note filed 7-19-95; operative 8-18-95 (Register 95, No. 29).

Note

Note: Authority cited: Sections 25150 and 25159, Health and Safety Code; and Governor's Reorganization Plan Number 1 of 1991. Reference: Sections 25159 and 25159.5, Health and Safety Code; and 40 CFR Section 265.310.