Cal. Code Regs. Tit. 27, div. 2, 1, ch. 3, subch. 2, art. 4, tbl. 4.1
Table 4.1 . Construction Standards for Units(1)
Subsurface Barriers | |||||||||
| Waste Mgmt Unit Classification | Type of Waste Management Unit | Clay Liner(2) | Synthetic Liner | Leachate Collection and Rem. System | Interim Cover | Cutoff Walls | Grout Curtains | Capacity of Precip & Drain. Control Facilities (Design Storm) | Seismic Design |
| Class II | Non MSW Landfill | Required(5), [LESS THAN EQUAL TO]1x10-6cm/sec | Not required | Required, blanket type | Required | [LESS THAN EQUAL TO]1x10-6 cm/sec(11) | [LESS THAN EQUAL TO]1x10-6 cm/sec | 1000-year 24-hour precipitation | Withstand maximum credible earthquake |
| Class II | MSW Landfill(13) | Special(13) | Special(13) | Special(13) | Required | [LESS THAN EQUAL TO]1x10-6 cm/sec(11) | [LESS THAN EQUAL TO]1x10-6 cm/sec | 1000-year 24-hour precipitation | Withstand maximum credible earthquake |
| Class II | Surface Impoundment | Double or single required(6), [LESS THAN EQUAL TO]1x10-6 cm/sec | Not required | Required with double liner, blanket type | Not required | [LESS THAN EQUAL TO]1x10-6 cm/sec(11) | [LESS THAN EQUAL TO]1x10-6 cm/sec | 1000-year 24-hour precipitation | Withstand maximum credible earthquake |
| Class II | Waste Pile | Optional(4,5), [LESS THAN EQUAL TO]1x10-6 cm/sec | Not required | May be required, blanket type | May be required | [LESS THAN EQUAL TO]1x10-6 cm/sec(11) | [LESS THAN EQUAL TO]1x10-6 cm/sec | 1000-year 24-hour precipitation | Withstand maximum credible earthquake |
| Class III | Non MSW Landfill | Optional, [LESS THAN EQUAL TO]1x10-6cm/sec (see § 20260) | Not required | Required if liner is required, blanket or dendritic | Required | [LESS THAN EQUAL TO]1x10-6 cm/sec, if required | [LESS THAN EQUAL TO]1x10-6 cm/sec, if required | 100-year 24-hour precipitation | Withstand at least the maximum probable earthquake (See § 20370) |
| Class III | MSW Landfill(13) | Special(13) | Special(13) | Special(13) | Required | [LESS THAN EQUAL TO]1x10-6 cm/sec, if required | [LESS THAN EQUAL TO]1x10-6 cm/sec, if required | 100-year 24-hour precipitation | Withstand at least the maximum probable earthquake (See § 20370) |
| 1 Applicable regulations in this article may provide for exemptions to certain requirements. § 20310(d) describes applicability to existing facilities. | |||||||||
| 2 All permeabilities specified in this table are maximum allowable permeabilities. | |||||||||
| 3 [Reserved.] Note: This footnote left in Ch-15 (of Division 3, Title 23, CCR), as it applies only to Class I Units. | |||||||||
| 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 § 21410 of this subchapter. The synthetic liner hydraulic conductivity shall be the same or less than that which would be required for a clay liner. | |||||||||
| 5 Clay liner required unless Units are underlain by a substantial thickness of natural geologic materials with hydraulic conductivity of 1x10-6 cm/sec [i.e., 1 foot/year] or less. | |||||||||
| 6 Single liner shall be a clay liner and removed or replaced as described in § 20330. Double liner systems shall have either an outer clay liner or shall be underlain by a substantial thickness of natural geologic materials with an hydraulic conductivity of 1x10-6 cm/sec [i.e., 1 foot/year] or less to act as an outer liner. | |||||||||
| 7 [Reserved.] | |||||||||
| 8 [Reserved.] | |||||||||
| 9 [Reserved.] | |||||||||
| 10 [Reserved.] | |||||||||
| 11 Cutoff walls required where there is potential for lateral movement of fluid, including waste or leachate, and the hydraulic conductivity of natural geologic materials is used for waste containment. | |||||||||
| 12 For Units other than MSW landfills, the RWQCB can grant an exemption to this design storm requirement if the discharger can demonstrate that the integrity of facilities will not be jeopardized if this criterion is not met. | |||||||||
| 13 All Class II or Class III landfills that received MSW at any time and that received solid waste after October 9, 1991 (MSW landfills) are subject to the additional state and federal requirements contained (or incorporated by reference) in SWRCB Resolution No. 93-62. | |||||||||
Footnotes for Figure 4.1: Summary of Liner Requirements for Classified Units (for MSW Landfills, see Additional Requirements in SWRCB Resolution No. 93-92).
a Requirements from Chapter 3, Subdivision 1 of this division.
b Designed to convey twice the anticipated volume of leachate; must ensure no buildup of hydraulic head on liner; blanket type required unless otherwise specified.
c Minimum 40 mils thick.
d Must be compatible with waste and/or leachate.
e Cutoff walls required where potential exists for lateral movement of waste or leachate.
f Acceptability of synthetic liner depends on nature of waste and duration of operation.
g Liner and waste to be removed at closure.
h Substantial thickness of natural geologic material with maximum hydraulic conductivity of 1x10-6 cm/sec (i.e., 1.0 foot/year). For MSW landfills, see SWRCB Resolution No. 93-62 for superseding containment system requirements.
i Minimum thickness of 2 feet; maximum hydraulic conductivity of 1x10-6 cm/sec (i.e., 1.0 foot/year). For MSW landfills, see SWRCB Resolution No. 93-62 for superseding containment system requirements.
j Liner removed or replaced before lower 25% (minimum 1 foot thickness) of the liner is penetrated by waste or leachate.
k Soil characteristics, distance from waste to ground water, and other factors must ensure no impairment of beneficial uses of ground water. Leachate collection system required for sludge disposal. For MSW landfills, see SWRCB Resolution No. 93-62 for superseding containment system requirements.
l Minimum thickness of 1 foot; maximum hydraulic conductivity of 1x10-6 cm/sec (i.e., 1.0 foot/year). For MSW landfills, see SWRCB Resolution No. 93-62 for superseding containment system requirements.
m Dendritic system allowed if wastes in contact with the liner will remain permeable and liner is sloped toward the system to prevent ponding. For MSW landfills, see SWRCB Resolution No. 93-62 for superseding containment system requirements.
Cal. Code Regs. Tit. 27, div. 2, 1, ch. 3, subch. 2, art. 4, tbl. 4.1