1. (a) Materials used in containment structures shall have appropriate chemical and physical properties to ensure that such structures do not fail to contain waste because of pressure gradients (including hydraulic head and external hydrogeologic forces), physical contact with the waste or leachate, chemical reactions with soil and rock, climatic conditions, the stress of installation, and the stress of daily operation.
2. (b) Permeabilities specified for containment structures other than cover shall be relative to the fluids, including waste and leachate, to be contained. Permeabilities specified for final cover shall be relative to water.
3. (c) Permeabilities shall be determined primarily by appropriate field test methods in accordance with accepted civil engineering practice. The results of laboratory tests with both water and leachate, and field tests with water, shall be compared to evaluate how the field permeabilities will be affected by leachate. Appropriate compaction tests may be used in conjunction with laboratory permeability tests to determine field permeabilities as long as a reasonable number of field permeability tests are also conducted. One acceptable method for testing the compatibility of leachate and clay liners (including the permeability of the liner to leachate) is given in Appendix I.

4. (d) Earthen materials used in containment structures other than cutoff walls and grout curtains shall consist of a mixture of clay and other suitable fine-grained soils which have the following characteristics, and which, in combination, can be compacted to attain the required permeability when installed. Liners made of such materials are referred to as “clay liners” in this chapter.

   1. (1) At least 30 percent of the material, by weight, shall pass a No. 200 U. S. Standard sieve.
   2. (2) The materials shall be fine-grained soils with a significant clay content and without organic matter, in the “SC” (clayey sand), “CL” (clay, sandy or silty clay), or “CH” (clay, sandy clay) classes of the Unified Soil Classification system.

5. (e) Construction standards for waste management units other than land treatment are given on Table 4.1 and in Figure 4.1.

   Table 4.1. Construction Standards for Waste Management Units¹

   Subsurface Barriers

   Waste Mgmt Unit Classification

   Type of Waste Management Unit

   Clay Liner⁽²⁾

   Synthetic Liner

   Leachate Collection and Removal System

   Interim Cover

   Cutoff Walls

   Grout Curtains

   Capacity of Precipitation and Drainage Control Facilities

   Seismic Design

   Class I

   Landfill

   required, ≤1*10^-7 cm/sec

   required⁽⁷⁾

   required, blanket type

   required

   ≤1*10^-7 cm/sec⁽¹⁰⁾

   ≤1*10^-7 cm/sec

   probable maximum precipitation

   withstand maximum credible earthquake

   Surface Impoundment

   double liner⁽³⁾ ≤1*10^-7 cm/sec

   required⁽⁸⁾

   required, blanket type

   ≤1*10^-7 cm/sec⁽¹⁰⁾

   ≤1*10^-7 cm/sec

   Waste Pile

   optional⁽⁴⁾ ≤1*10^-7 cm/sec

   may be⁽⁹⁾ required

   required, blanket type

   required

   ≤1*10^-7 cm/sec⁽¹⁰⁾

   ≤1*10^-7 cm/sec

   ¹ Applicable regulations in this article may provide for exemptions to certain requirements. Subsection 2540(d) of this article describes applicability to existing facilities.

   ² All permeabilities specified in this table are maximum allowable permeabilities.

   ³ Outer liner shall be a clay liner; inner liner may be a synthetic liner instead of a clay liner if inspected according to Subsection 2548(f) of this article.

   ⁴ A synthetic liner alone may be allowed based on nature of waste to be contained and duration of the operation. A waste pile with a synthetic liner alone may not be closed as a landfill pursuant to Section 2583 of this chapter. The synthetic liner permeability shall be the same or less than that which would be required for a clay liner.

   ⁵ [Reserved.]

   ⁶ [Reserved.]

   ⁷ Synthetic inner liner required in addition to a clay outer liner unless exempted pursuant to Subsection2510(b) of this chapter.

   ⁸ Synthetic inner liner required in addition to a clay liner unless the surface impoundment is closed according to Subsection 2582(b)(1)of this chapter, or unless exempted pursuant to Subsection 2510(b) of this chapter.

   ⁹ Synthetic inner liner required unless the pile is closed according to Subsection 2583(a)(1), or unless exempted pursuant to Subsection 2510(b) of this chapter.

   ¹⁰ Cutoff walls required where there is potential for lateral movement of fluid, including waste or leachate.

   

Note: Authority cited: Section 1058, Water Code. Reference: Sections 13172 and 13360, Water Code.

History

1. Amendment of Table 4.1 and new footnotes 7, 8 and 9 filed 6-12-85; effective upon filing pursuant to Government Code Section 11346.2(d) (Register 85, No. 24).

2. Amendment of subsections (d) and (e), Table 4.1 and Figure 4.1, and repealer of figure 4.2 filed 6-18-97; operative 7-18-97 (Register 97, No. 25).