(1) Applicability. These requirements apply to MSWLF units except:
(a)  When the MSWLF unit meets the conditions for exemption in 40 C.F.R. § 258.1(f); provided however, that the director may, at his discretion, require monitoring of a MSWLF unit which meets the conditions for exemption in 40 C.F.R. § 258.1(f), if necessary to protect ground water resources. If the director does require ground water monitoring of such MSWLF unit, a method other than the ground water monitoring wells required in this section and in 40 C.F.R. § 258.51 through 258.55 may be used to detect a release of contamination from the unit; or
(b)  When suspended upon demonstration in accordance with 40 C.F.R. § 258.50 that there is no potential for migration of hazardous constituents from the MSWLF unit to the uppermost aquifer during the active life of the unit and the post-closure care periods when certified by a qualified professional and approved by the director.
(2)  Ground water monitoring program. All monitoring programs shall be conducted in a manner consistent with the guidance of relevant portions of appendix F per the "Federal Register" of October 9, 1991. The schedule for compliance as provided by 40 C.F.R. § 258.50 shall apply unless an alternative schedule is approved by the director.
(a)  A ground water monitoring system must be installed that consists of a sufficient number of wells, installed at appropriate locations and depths, to conform with the requirements of 40 C.F.R. § 258.51(a) and (d).
(b)  A multiunit ground water monitoring system may be constructed instead of separate ground water monitoring systems for each MSWLF unit as provided in 40 C.F.R. § 258.51(b).
(c)  Monitoring wells must be cased in a manner that maintains the integrity of the monitoring well bore hole as provided in 40 C.F.R. § 258.51(c). Wells must be constructed in such a manner as to prevent contamination of the samples, the sampled strata, and between aquifers and water bearing strata, and in accordance with Idaho department of water resources, well construction standards and the monitoring well standards of the national ground water association.

Terms Used In Idaho Code 39-7410

  • 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
  • Month: means a calendar month, unless otherwise expressed. See Idaho Code 73-114
  • Owner: means the person(s) who owns a facility or part of a facility. 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
  • Property: includes both real and personal property. See Idaho Code 73-114
  • 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
  • Waste management unit boundary: means a vertical surface located at the hydraulically downgradient limit of the unit. See Idaho Code 39-7403
(3)  Point of compliance. For each MSWLF unit, the relevant point of compliance shall be set as a function of site and monitoring program design subject to the approval of the director. The relevant point of compliance for purposes of MSWLF unit design, well location and corrective action shall be:
(a)  Located within the flow pathway(s) predicted from the results of the hydrogeologic investigation;
(b)  No more than one hundred fifty (150) meters downgradient from the waste management unit boundary;
(c)  On contiguous property owned, or otherwise subject to possessory rights by the MSWLF owner;
(d)  Shall be identified by the qualified professional on all reports and documents pertaining to analysis of ground water protection measures; and
(e)  Determined in consideration of factors provided in 40 C.F.R. § 258.40(d).
(4)  Ground water characterization, sampling and analysis requirements.
(a)  The ground water monitoring system must include sampling and analysis procedures consistent with 40 C.F.R. § 258.53.
(b)  Monitoring wells shall be tested for the constituents listed in 40 C.F.R. § part 258, appendix I, plus temperature, unless otherwise authorized by the director as provided in 40 C.F.R. § 258.54.
(c)  Background values will be based on an independent sample from each well sampled at three (3) month intervals in a one (1) year period.
(5)  Detection monitoring program.
(a)  Detection monitoring is required throughout the active life and post-closure care period at MSWLF units as provided in 40 C.F.R. § 258.54 at all ground water monitoring wells as defined in 40 C.F.R. § 258.51(a)(1) and (a)(2) for constituents listed in 40 C.F.R. § part 258, appendix I.
(b)  Each well shall be monitored on a semiannual basis after background characterization. Alternative constituents and sampling frequency may be approved by the director based upon considerations as defined in 40 C.F.R. § 258.54 (a)(2) and (b). Requests for alternative constituents or frequency shall be based on a report certified by a qualified professional.
(c)  Each ground water sample event must include a determination of the ground water surface elevation, flow direction and rate.