Utah Admin. Code R315-308-2 - Ground Water Monitoring Requirements

(1) Each facility owner or operator that is required to conduct ground water monitoring shall formulate a ground water monitoring plan that addresses the requirements of Section R315-308-2.

(2) The ground water monitoring system must consist of at least one background or upgradient well and two downgradient wells, installed at appropriate locations and depths to yield ground water samples from the uppermost aquifer and all hydraulically connected aquifers below the facility, cell, or unit. The downgradient wells shall be designated as the point of compliance and must be installed at the closest practicable distance hydraulically down gradient from the unit boundary not to exceed 150 meters (500 feet) and must also be on the property of the owner or operator:

(a) the upgradient well must represent the quality of background water that has not been affected by leakage from the active area; and

(b) the downgradient wells must represent the quality of ground water passing the point of compliance. Additional wells may be required by the Director in complicated hydrogeological settings or to define the extent of contamination detected.

(3) All monitoring wells must be cased in a manner that maintains the integrity of the monitoring well bore hole. This casing must allow collection of representative ground water samples. 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. All monitoring wells and all other devices and equipment used in the monitoring program must be operated and maintained so that they perform to design specifications throughout the life of the monitoring program.

(4) The ground water monitoring program must include at a minimum, procedures and techniques for:

(a) well construction and completion;

(b) decontamination of drilling and sampling equipment;

(c) sample collection;

(d) sample preservation and shipment;

(e) analytical procedures and quality assurance;

(f) chain of custody control or sample tracking, as approved by the Director; and

(g) procedures to ensure employee health and safety during well installation and monitoring.

(5) Each facility shall utilize a laboratory, that is certified by the state for the test methods used, to complete tests, using methods with appropriate detection levels, on samples for the following:

(a) during the first year of facility operation after wells are installed or an alternative schedule as approved by the Director, a minimum of eight independent samples from the upgradient and four independent samples from each downgradient well for all parameters listed in Section R315-308-4 to establish background concentrations;

(b) after background levels have been established, a minimum of one sample, semiannually, from each well, background and downgradient, for all parameters listed in Section R315-308-4 as a detection monitoring program;

(i) In the detection monitoring program, the owner or operator must determine ground water quality at each monitoring well on a semiannual basis during the life of an active area, including the closure period, and the post- closure care period.

(ii) The owner or operator must express the ground water quality at each monitoring well in a form appropriate for the determination of statistically significant changes;

(c) field-measured pH, water temperature, and water conductivity must accompany each sample collected;

(d) analysis for the heavy metals and the organic constituents from Section R315-308-4 shall be completed on unfiltered samples; and

(e) the Director may specify additional or fewer constituents depending upon the nature of the ground water or the waste on a site specific basis considering:

(i) the types, quantities, and concentrations of constituents in wastes managed at the landfill;

(ii) the mobility, stability, and persistence of waste constituents or their reaction products in the unsaturated zone beneath the landfill;

(iii) the detectability of indicator parameters, waste constituents, and reaction products in the ground water; and

(iv) the background concentration or values and coefficients of variation of monitoring parameters or constituents in the ground water.

(f) The following information shall be placed in the facility's operating record and a copy submitted to the Director as the ground water monitoring results to be included in the annual report required by Subsection R315-302-2(4):

(i) a report on the procedures, including the quality control/quality assurance, followed during the collection of the ground water samples;

(ii) the results of the field measured parameters required by Subsections R315-308-2(5)(c) and R315-308-2(7);

(iii) a report of the chain of custody and quality control/quality assurance procedures of the laboratory;

(iv) the results of the laboratory analysis of the constituents specified in Section R315-308-4 or an alternative list of constituents approved by the Director:

(A) the results of the laboratory analysis shall list the constituents by name and CAS number; and

(B) a list of the detection limits and the test methods used; and

(v) the statistical analysis of the results of the ground water monitoring as required by Subsection R315-308-2(8).

(vi) The results of the ground water monitoring may be submitted in electronic format.

(6) After background constituent levels have been established, a ground water quality protection standard shall be set by the Director which shall become part of the ground water monitoring plan. The ground water quality protection standard will be set as follows.

(a) For constituents with background levels below the standards listed in Section R315-308-4 or as listed in Section R315-308-5, which presents the ground water protection standards that are available for the constituents listed as Appendix II in 40 CFR 258, the ground water quality standards of Sections R315-308-4 and R315-308-5 shall be the ground water quality protection standard.

(b) If a constituent is detected and a background level is established but the ground water quality standard for the constituent is not included in Section R315-308-4 or Section R315-308-5 the ground water quality protection standard for that constituent shall be set according to health risk standards.

(c) If a constituent is detected and a background level is established and the established background level is higher than the value listed in Section R315-308-4, R315-308-5 or the level established according to Subsection R315-308-2(6)(b), the ground water quality protection standard shall be the background concentration.

(7) The ground water monitoring program must include a determination of the ground water surface elevation each time ground water is sampled.

(8) The owner or operator shall use a statistical method for determining whether a significant change has occurred as compared to background. The Director will approve such a method as part of the ground water monitoring plan. Possible statistical methods include:

(a) a parametric analysis of variance (ANOVA) followed by multiple comparisons procedures to identify statistically significant evidence of contamination. The method must include estimation and testing of the contrasts between each compliance well's mean and the background mean levels for each constituent;

(b) an analysis of variance (ANOVA) based on ranks followed by multiple comparisons procedures to identify statistically significant evidence of contamination. The method must include estimation and testing of the contrasts between each compliance well's median and the background median levels for each constituent;

(c) a tolerance or prediction interval procedure in which an interval for each constituent is established from the distribution of the background data, and the level of each constituent in each compliance well is compared to the upper tolerance or prediction limit;

(d) a control chart approach that gives control limits for each constituent; or

(e) another statistical test method approved by the Director.

(9) For both detection monitoring, as described in Subsection R315-308-2(5), and assessment monitoring, as described in Subsection R315-308-2(12), the Director may specify additional or fewer sampling and analysis events, no less than annually, depending upon the nature of the ground water or the waste on a site-specific basis considering:

(a) lithology of the aquifer and unsaturated zone;

(b) hydraulic conductivity of the aquifer and unsaturated zone;

(c) ground water flow rates;

(d) minimum distance between upgradient edge of the landfill unit and downgradient monitoring well screen (minimum distance of travel); and

(e) resource value of the aquifer.

(10) The owner or operator must determine and report the ground water flow rate and direction in the upper most aquifer each time the ground water is sampled.

(11) If the owner or operator determines that there is a statistically significant increase over background in any parameter or constituent at any monitoring well at the compliance point, the owner or operator must:

(a) within 14 days of the completion of the statistical analysis of the sample results and within 30 days of the receipt of the sample results, enter the information in the operating record and notify the Director of this finding in writing. The notification must indicate what parameters or constituents have shown statistically significant changes; and

(b) immediately resample the ground water in all monitoring wells, both background and downgradient, or in a subset of wells specified by the Director, and determine:

(i) the concentration of all constituents listed in Section R315-308-4, including additional constituents that may have been identified in the approved ground water monitoring plan;

(ii) if there is a statistically significant increase over background of any parameter or constituent in any monitoring well at the compliance point; and

(iii) notify the Director in writing within seven days of the completion of the statistical analysis of the sample results.

(c) The owner or operator may demonstrate that a source other than the solid waste disposal facility caused the contamination or that the statistically significant change resulted from error in sampling, analysis, statistical evaluation, or natural variation in ground water quality. A report documenting this demonstration must be certified by a qualified ground-water scientist and approved by the Director and entered in the operating record. If a successful demonstration is made and documented, the owner or operator may continue monitoring as specified in Subsection R315-308-2(5)(b).

(12) If, after 90 days, a successful demonstration as stipulated in Subsection R315-308-2(11)(c) is not made, the owner or operator must initiate the assessment monitoring program required as follows:

(a) within 14 days of the determination that a successful demonstration is not made, take one sample from each downgradient well and analyze for all constituents listed as Appendix II in 40 CFR Part 258, 2001 ed., which is adopted and incorporated by reference.

(b) for any constituent detected from Appendix II, 40 CFR Part 258, in the downgradient wells a minimum of four independent samples from the upgradient and four independent samples from each downgradient well must be collected, analyzed, and statistically evaluated to establish background concentration levels for the constituents; and

(c) within 14 days of the completion of the statistical analysis of the sample results and within 30 days of the receipt of the sample results, place a notice in the operation record and notify the Director in writing identifying the Appendix II, 40 CFR Part 258, constituents and their concentrations that have been detected as well as background levels. The Director shall establish a ground water quality protection standard pursuant to Subsection R315-308-2(6) for any Appendix II, 40 CFR Part 258, constituent detected in the downgradient wells.

(d) The owner or operator shall thereafter resample:

(i) at a minimum, all downgradient wells on a quarterly basis for all constituents in Section R315-308-4, or the alternative list that may have been approved as part of the permit, and for those constituents detected from Appendix II, 40 CFR Part 258;

(ii) the downgradient wells on an annual basis for all constituents in Appendix II, 40 CFR Part 258; and

(iii) statistically analyze the results of all ground water monitoring samples.

(e) The Director may specify additional or fewer constituents depending upon the nature of the ground water or the waste on a site specific basis considering:

(i) the types, quantities, and concentrations of constituents in wastes managed at the landfill;

(ii) the mobility, stability, and persistence of waste constituents or their reaction products in the unsaturated zone beneath the landfill;

(iii) the detectability of indicator parameters, waste constituents, and reaction products in the ground water; and

(iv) the background concentration or values and coefficients of variation of monitoring parameters or constituents in the ground water.

(f) If after two consecutive sampling events, the concentrations of all constituents being analyzed in Subsection R315-308-2(12)(d)(i) are shown to be at or below established background values, the owner or operator must notify the Director of this finding and may, upon the approval of the Director, return to the monitoring schedule and constituents as specified in Subsection R315-308-2(5)(b).

(13) If one or more constituents from Section R315-308-4 or the approved alternative list, or from those detected from Appendix II, 40 CFR Part 258, are detected at statistically significant levels above the ground water quality protection standard as established pursuant to Subsection R315-308-2(6) in any sampling event, the owner or operator must:

(a) within 14 days of the receipt of this finding, place a notice in the operating record identifying the constituents and concentrations that have exceeded the ground water quality standard. Within the same time period, the owner or operator must also notify the Director and all appropriate local governmental and local health officials that the ground water quality standard has been exceeded;

(b) characterize the nature and extent of the release by installing additional monitoring wells as necessary;

(c) install at least one additional monitoring well at the facility boundary in the direction of contaminant migration and sample this well and analyze the sample for the constituents in Section R315-308-4 or the approved alternative list and the detected constituents from Appendix II, 40 CFR Part 258; and

(d) notify all persons who own the land or reside on the land that directly overlies any part of the plume of contamination if contaminants have migrated off-site as indicated by sampling of wells in accordance with Subsections R315-308-2(13)(b) and (13)(c).

(e) The owner or operator may demonstrate that a source other than the solid waste disposal facility caused the contamination or that the statistically significant change resulted from error in sampling, analysis, statistical evaluation, or natural variation in ground water quality. A report documenting this demonstration must be certified by a qualified ground-water scientist and approved by the Director and entered in the operating record. If a successful demonstration is made, documented and approved, the owner or operator may continue monitoring as specified in Subsection R315-308-2(12)(d) or Subsection R315-308-2(12)(e) when applicable.

Notes

Utah Admin. Code R315-308-2