NR 102.50 NR 102.50 Waterbody assessments and reporting. As required under sections 303 (d) and 305 (b) of the Clean Water Act, 33 USC 1313 (d) and 1315 (b), the department shall report to U.S. EPA on the status of the state’s waterbodies and attainment of water quality standards every two years. Waterbody assessments are used to determine the condition of the state’s surface waters or segments thereof and whether waterbodies are attaining state and federal surface water quality standards.

NR 102.50 History History: CR 19-094: cr. Register September 2022 No. 801, eff. 10-1-22.

NR 102.51 NR 102.51 Assessment types. The department may conduct different types of assessments to determine the status of waterbody health and attainment of water quality standards, depending on availability of data or methods used to collect the data. The department shall, at a minimum, conduct all of the following:

NR 102.51(1) (1) Statewide condition assessments. As part of the biennial assessment report required under section 305 (b) of the Clean Water Act, 33 USC 1315 (b), and 40 CFR 130.8 and 130.10 (a) (1), the department shall report on water quality status and trends at the state, regional, or watershed levels. The department shall assess the extent to which surface waters of the state provide for the protection and propagation of a balanced population of shellfish, fish, and wildlife, and allow recreational activities in and on the water. Broad-scale approaches may be used to conduct these assessments, including randomized monitoring designs or other appropriate statistical methods.

NR 102.51(2) (2) Individual waterbody assessments and section 303 (d) list.

NR 102.51(2)(a) (a) The department shall identify and report on waters not meeting any applicable water quality standard prescribed under statute or a promulgated rule, pursuant to section 303 (d) of the Clean Water Act, 33 USC 1313 (d), and 40 CFR 130.7 (b) and 130.10 (b) (2). The department shall assess individual waterbodies that have sufficient and readily available datasets, as specified in the department’s water quality standards and assessment protocols, to determine whether a waterbody is attaining water quality standards. The department determines whether a waterbody’s designated uses are supported by evaluating attainment of its water quality criteria and biological assessment thresholds. The department shall assess data collected from a waterbody against each applicable water quality standard or assessment threshold independently, unless a combined assessment procedure is specified in rule. The department shall report any waters not attaining applicable water quality standards to the U.S. EPA. Only water quality standards that have been promulgated via statute or rule may be considered for the purposes of listing a waterbody on the section 303 (d) list.

NR 102.51(2)(b) (b) When the department submits the section 305 (b) biennial assessment report and section 303 (d) list, it shall provide all of the following information if an assessment indicates that one or more of a waterbody’s water quality standards are not attained:

NR 102.51(2)(b)1. 1. A waterbody is listed on the section 303 (d) list for a pollutant if a pollutant’s water quality criterion is not attained and it may require a total maximum daily load analysis.

NR 102.51(2)(b)2. 2. A waterbody is reported as having an observed effect of degradation if the waterbody does not attain one or more biological assessment thresholds or water quality criteria for parameters that are not pollutants, such as dissolved oxygen. In listing observed effects, the department may not formally attribute these effects to a specific pollutant until the department conducts an evaluation of potential causes, including nonchemical stressors such as habitat degradation or hydrological modification, and identifies one or more specific pollutants as causing or contributing to biological degradation. Listing of observed effects would not require development of a total daily maximum load for a waterbody unless a specific pollutant exceeding its promulgated water quality standard is identified by the department as a cause of the observed effect.

NR 102.51 Note Note: If a waterbody is not attaining water quality criteria for a pollutant, it will be listed on the section 303 (d) list regardless of attainment of biological assessment thresholds unless otherwise specified in the pollutant’s criteria or procedures specified in those chapters (for instance, the combined assessment approach for phosphorus under s. NR 102.60), or if site-specific criteria are developed and attained.

NR 102.51 Note Note: This subsection does not preclude other types of assessments that may be needed or required for other purposes. The department has authority to research and assess the quality and condition of the state’s waters under s. 281.13, Stats.

NR 102.51 Note Note: As required under 40 CFR 130.7 (b) (4), waters on the section 303 (d) list may require a total maximum daily load analysis. The department prioritizes and develops total maximum daily load analyses as discussed in subch. III of ch. NR 212. In addition, if a specific pollutant is identified as contributing to biological degradation, a site-specific criterion for the pollutant may be developed through rulemaking if appropriate.

NR 102.51 History History: CR 19-094: cr. Register September 2022 No. 801, eff. 10-1-22.

NR 102.52 NR 102.52 Assessment protocols.

NR 102.52(1) (1) General. The department’s protocols for assessing waterbodies shall be consistent with the state’s water quality standards and federal regulations and be based on relevant scientific information. The department’s protocols may include components such as minimum data requirements, sampling methods, quality control, statistical analysis of data, allowable frequency of exceedance of criteria or thresholds, and use of professional judgment.

NR 102.52 Note Note: When assessing waterbodies, the department uses its guidance for waterbody assessments titled “Wisconsin Consolidated Assessment and Listing Methodology,” or WisCALM. Although a description of the state’s assessment methodology is required to be submitted to U.S. EPA, U.S. EPA does not approve or disapprove the state’s assessment methodology under section 303 (d) of the Clean Water Act.

NR 102.52(2) (2) Sample variability and confidence intervals.

NR 102.52(2)(a) (a) For assessment determinations, the department may determine that multiple samples are necessary to account for variability inherent in the waterbody, sampling results, or other conditions. The department may evaluate attainment of criteria or thresholds, using assessment methodology that accounts for both the central tendency of the data, such as the mean or median, and the variability of the samples.

NR 102.52(2)(b) (b) The department may apply a confidence interval approach to determine the number of samples needed and to increase certainty in the attainment decision. For metrics expressed as a mean or percentile of a group of samples, the department may use the two-sided 80 percent confidence interval of the mean or percentile for assessment. Other methods of calculating a confidence interval may be applied as appropriate for a specific metric, data type, or statistical goal. Once the confidence interval is determined under this paragraph, it is then compared to the criterion or threshold as specified in par. (c).

NR 102.52(2)(c) (c) When applying an approach under par. (b), the department shall compare the confidence interval to the applicable criterion or threshold using one of the following evaluation criteria:

NR 102.52(2)(c)1. 1. If the entire confidence interval is attaining the criterion or threshold, no further samples are needed to make the attainment determination.

NR 102.52(2)(c)2. 2. If the entire confidence interval is not attaining the criterion or threshold, no further samples are needed to make the non-attainment determination.

NR 102.52(2)(c)3. 3. If the criterion or threshold is within the confidence interval, the assessment will be deferred until more data can be collected with the goal of narrowing the interval to determine whether subd. 1. or 2. applies. After further data collection, if the criterion or threshold continues to be within the confidence interval, the attainment determination shall be made by directly comparing the sample mean or percentile to the criterion or threshold.

NR 102.52 Note Note: With confidence intervals calculated under par. (b), there is 90 percent confidence that the attainment decision is correct because there is 80 percent confidence that the waterbody’s true value is within the interval, 10 percent confidence that it is greater than the interval, and 10 percent confidence that it is less than the interval.

NR 102.52 History History: CR 19-094: cr. Register September 2022 No. 801, eff. 10-1-22.

NR 102.53 NR 102.53 Reporting, public participation, and approvals.

NR 102.53(1) (1) Report development. For development of the biennial assessment report and section 303 (d) list, the department shall assemble, evaluate, and submit water quality-related data, information, and assessment protocols to U.S. EPA.

NR 102.53(2) (2) Public participation.

NR 102.53(2)(a) (a) The department shall solicit assessment data from citizens and partner groups prior to the waterbody assessment process. Readily available data sets that meet minimum data requirements and are submitted in the department’s specified format during the biennial data solicitation period shall be considered by the department when conducting assessments.