NR 665.0092(3)(a)(a) For all monitoring wells, the owner or operator shall establish initial background concentrations or values of all parameters specified in sub. (2). The owner or operator shall do this quarterly for one year.

NR 665.0092(3)(b)(b) For each of the indicator parameters specified in sub. (2) (c), at least 4 replicate measurements shall be obtained for each sample and the initial background arithmetic mean and variance shall be determined by pooling the replicate measurements for the respective parameter concentrations or values in samples obtained from upgradient wells during the first year.

NR 665.0092(4)(4) After the first year, all monitoring wells shall be sampled and the samples analyzed with the following frequencies:

NR 665.0092(4)(a)(a) Samples collected to establish groundwater quality shall be obtained and analyzed for the parameters specified in sub. (2) (b) at least annually.

NR 665.0092(4)(b)(b) Samples collected to indicate groundwater contamination shall be obtained and analyzed for the parameters specified in sub. (2) (c) at least semi-annually.

NR 665.0092(5)(5) Elevation of the groundwater surface at each monitoring well shall be determined each time a sample is obtained.

NR 665.0092 HistoryHistory: CR 05-032: cr. Register July 2006 No. 607, eff. 8-1-06; correction in (2) (a) made under s. 13.92 (4) (b) 7., Stats., Register March 2013 No. 687.

NR 665.0093(1)(1) By August 1, 1982, the owner or operator shall prepare an outline of a groundwater quality assessment program. The outline shall describe a more comprehensive groundwater monitoring program (than that described in ss. NR 665.0091 and 665.0092) capable of determining all of the following:

NR 665.0093(2)(2) For each indicator parameter specified in s. NR 665.0092 (2) (c), the owner or operator shall calculate the arithmetic mean and variance, based on at least 4 replicate measurements on each sample, for each well monitored in accordance with s. NR 665.0092 (4) (b), and compare these results with its initial background arithmetic mean. The comparison shall consider individually each of the wells in the monitoring system, and shall use the Student’s t-test at the 0.01 level of significance (see ch. NR 665 Appendix IV) to determine statistically significant increases (and decreases, in the case of pH) over initial background.

NR 665.0093(3)(a)(a) If the comparisons for the upgradient wells made under sub. (2) show a significant increase (or pH decrease), the owner or operator shall submit this information in accordance with s. NR 665.0094 (1) (b) 2.

NR 665.0093(3)(b)(b) If the comparisons for downgradient wells made under sub. (2) show a significant increase (or pH decrease), the owner or operator shall then immediately obtain additional groundwater samples from those downgradient wells where a significant difference was detected, split the samples in 2 and obtain analyses of all additional samples to determine whether the significant difference was a result of laboratory error.

NR 665.0093(4)(a)(a) If the analyses performed under sub. (3) (b) confirm the significant increase (or pH decrease), the owner or operator shall provide written notice to the department—within 7 days of the date of the confirmation—that the facility may be affecting groundwater quality.

NR 665.0093(4)(b)(b) Within 15 days after the notification under par. (a), the owner or operator shall develop and submit to the department a specific plan, based on the outline required under sub. (1) and certified by a qualified geologist or geotechnical engineer, for a groundwater quality assessment program at the facility. This plan shall be placed in the facility’s operating record and be maintained until closure of the facility.

NR 665.0093(4)(c)2.2. Sampling and analytical methods for those hazardous wastes or hazardous waste constituents in the facility.

NR 665.0093(4)(d)(d) The owner or operator shall implement the groundwater quality assessment plan which satisfies the requirements of par. (c), and, at a minimum, determine all of the following:

NR 665.0093(4)(d)1.1. The rate and extent of migration of the hazardous waste or hazardous waste constituents in the groundwater.

NR 665.0093(4)(e)(e) The owner or operator shall make the first determination under par. (d) as soon as technically feasible, and, within 15 days after that determination, submit to the department a written report containing an assessment of the groundwater quality. This report shall be placed in the facility’s operating record and be maintained until closure of the facility.