(1) Applicability. These standards apply to new MSWLF units and lateral expansions of existing facilities as provided in 40 C.F.R. § 258.40.
(2)  Liner designs. All owners or operators of MSWLF units shall use one (1) of the following designs:
(a)  Composite liner design. A liner as provided under 40 C.F.R. § 258.40(b) and shall include a leachate collection system as provided under 40 C.F.R. § 258.40(a)(2); or
(b)  Alternate liner design. A site-specific design based upon environmental performance, as allowed under 40 C.F.R. § 258.40(a)(1) which will ensure that the concentration values listed in table 1, 40 C.F.R. § 258.40, or as amended, will not be exceeded in the uppermost aquifer at the relevant point of compliance. This design shall demonstrate consideration of site specific factors as provided in 40 C.F.R. § 258.40(c) and shall include a leachate collection system as provided under 40 C.F.R. § 258.40(a)(2); or
(c)  Arid design. A site-specific design based upon environmental performance, as allowed under 40 C.F.R. § 258.40(a)(1) which will ensure that the concentration values listed in table 1, 40 C.F.R. § 258.40, or as amended, will not be exceeded in the uppermost aquifer at the relevant point of compliance. This design shall use both field collected data and predictions that maximize contaminant migration for demonstrating no potential for migration. This design will apply to locations having less than twenty-five (25) inches of precipitation annually, net evaporative losses greater than thirty (30) inches annually, and holding capacity in native soils greater than annual absorbance; and
(i)   solid waste is deposited no less than fifty (50) feet above the seasonal high level of ground water in the uppermost aquifer;
(ii)  the geologic formation beneath the site and above the uppermost aquifer must have capillary capacities greater than the projected maximum volume of leachate generated during the active life of the MSWLF unit; and
(iii) "no potential for migration" is demonstrated when the geologic formation beneath the site and above the uppermost aquifer has sufficient hydrogeological characteristics and holding capacity adequate to contain all hazardous constituents generated during the active life, closure and post-closure care periods.

Terms Used In Idaho Code 39-7409

  • Aquifer: means a geological formation, group of formations, or a portion of a formation capable of yielding significant quantities of ground water to wells or springs. See Idaho Code 39-7403
  • Director: means the director of the Idaho department of environmental quality. See Idaho Code 39-7403
  • Ground water: means water below the land surface in a zone of saturation. See Idaho Code 39-7403
  • Leachate: means a liquid that has passed through or emerged from solid waste and contains soluble, suspended or miscible materials removed from such waste. See Idaho Code 39-7403
  • Point of compliance: means a vertical surface located at the hydraulically downgradient intercept with the uppermost aquifer at which a release from a waste management unit measured as change in constituent values will trigger assessment monitoring. See Idaho Code 39-7403
  • Qualified professional: means a licensed professional geologist or licensed professional engineer, as appropriate, holding current professional registration in compliance with applicable provisions of the Idaho Code. See Idaho Code 39-7403
  • Uppermost aquifer: means the geological formation nearest the natural ground surface that is an aquifer as well as lower aquifers that are hydraulically interconnected with this aquifer within the facility’s property boundary. See Idaho Code 39-7403
(3)  Point of compliance. For each MSWLF unit, the relevant point of compliance shall be set by a qualified professional by criteria contained in 40 C.F.R. § 258.40(d)(1) through (d)(8), inclusive, subject to approval by the director.
(4)  Leachate discharge shall comply with permitted discharge requirements under the federal clean water act (PL 95-217) and federal storm water discharge regulations (40 C.F.R. part 122).