Ground water quality monitoring

1. An owner or operator of a resource recovery unit, a land treatment unit, a surface impoundment, or a landfill, except an inert waste landfill, must incorporate a ground water monitoring system into the design of the facility. An owner or operator of a CCR unit that is subject to the provisions of chapter 33.1-20-08 is exempt from the requirements of this section. If the owner or operator demonstrates to the department that there is no potential for migration of solid waste constituents to the uppermost aquifer during the life of the solid waste management unit and the postclosure period, the department may suspend this requirement. The demonstration must be based upon factors such as the site characterization, the solid waste characteristics and constituents, the potential capacity of the unit or facility, and the physical, chemical, and biological processes affecting contaminant fate and transport. 2. Ground water monitoring systems must be designed to effectively detect the migration of contamination. At a minimum, a water quality monitoring system shall: a. Include one ground water monitoring well located upgradient of the solid waste management unit, and at least two wells located downgradient of the unit. The monitoring wells should be installed at appropriate locations and depths to yield ground water from the uppermost aquifer and all hydraulically connected aquifers below the solid waste management units on the facility; b. Represent the elevation of ground water in each well immediately prior to purging so that the owner or operator may determine the rate and direction of ground water flow each time ground water is sampled; c. Represent the quality of ground water that has not been affected by spills or leakage from solid waste management units; d. Represent the quality of ground water to ensure detection of contamination passing the compliance boundary; e. Ground water samples at municipal waste landfills must not be filtered prior to analysis; and f. The frequency and number of samples collected must be consistent with statistical procedures for evaluating ground water data. A minimum of four independent samples from each well must be collected for analysis during the first sampling event for establishing background data at upgradient (subdivision c) and downgradient (subdivision d) wells, unless four or more sampling events occur prior to acceptance of solid waste by the facility. The monitoring frequency must be semiannual during the active life of the facility and during the postclosure period. The department may specify an alternate frequency for sampling based upon such factors as site hydrogeological characteristics, solid waste characteristics, evidence of a spill or leakage, or resource value of the aquifer. 3. Additional wells may be required in complicated hydrogeological settings or to define the extent of contamination detected. 4. A written ground water monitoring plan must be developed for approval by the department and implemented as part of the permitting process. The plan must include: a. Number and location of wells; b. Procedures for decontamination of drilling and sampling equipment; c. Procedures for sample collection; d. Sample analytical procedures; e. Chain of custody control; f. Parameters for analysis; g. Quality assurance or quality control procedures; h. A monitoring schedule; i. Data statistical methods and analysis procedures; and j. Reporting of a statistically significant increase over a background value or of an exceedance of a maximum concentration limit or a water quality standard. 5. Ground water monitoring data obtained under this section must be analyzed within a reasonable period of time after completing sampling and laboratory analysis to determine whether or not a statistically significant increase over background values or an exceedance of a maximum concentration limit or water quality standard has occurred for each parameter required in the monitoring plan or permit. Statistical methods must, as appropriate: a. Be appropriate for the distribution of the data and, if inappropriate for a normal theory test, be transformed or a distribution-free theory test must be used. b. Control or correct for seasonal and spatial variability in the data. c. Account for data below the limit of detection that can be reliably achieved by routine laboratory techniques, using the limit as the lowest concentration level for a chemical parameter which is below detection. d. Be protective of human health and environmental resources.