Department of
Environmental Quality

DEQ evaluates the scientific rigor and relevance of non-DEQ data to determine where and how it will be incorporated into the assessment process. Numeric data that relate to specific water quality criteria are evaluated according to the criteria exceedance policy. Other types of data may be used to affirm or change a use support determination based on the scientific rigor and relevance used to collect and analyze the data, as well as its significance to the assessment process.

DEQ uses a tiered approach to provide consistent weighting and consideration of various types of data. Initial aquatic life support status calls may be confirmed or modified based on other available information.

Tier I

The scientific rigor of Tier I data is characterized as high and typically includes monitored data collected by professional scientists or professionally trained technicians. The data are collected and analyzed under a monitoring plan with quality assurance. Biological data may come from one of several different assemblages, such as macroinvertebrates, fish, or algae. Physical habitat data may have quantitative measurements and standardized qualitative assessment procedures.

To be considered relevant, Tier I data usually includes direct measurements or observations of beneficial uses, criteria, or causes of impairment. In addition, the sampling needs to have been conducted at multiple times and locations or at a representative location with specific locations identified on a map or with GIS. Predictive models must include calibration factors. The information must be five years old or less and must be able to be differentiated along a gradient of environmental conditions.

Examples of the types of monitoring data typically meeting Tier I criteria include BURP, EMAP, RBP, Use Attainability Analyses, graduate theses, and professionally prepared and peer-reviewed studies or reports. Tier I data are of sufficient quality and relevance to be used for 303(d) listing decisions, 305(b) reports, subbasin assessments, and TMDL development. Data must meet both scientific rigor and relevance of Tier I criteria to be classified at the Tier I level.

Tier II

DEQ characterizes the scientific rigor of Tier II data as qualitative or semi-quantitative data. The data collectors will have followed documented field, laboratory, and data-handling protocols. Tier II data include professionally conducted evaluations and habitat data consisting primarily of standardized visual assessments or evaluations. Relevant data may include evaluations based on monitored or evaluated data more than five years old, watershed land use information, modeling results with estimated inputs, or measurement of an atypical event.

Data collected for Environmental Assessments, Proper Functioning Condition (PFC) assessments, Cumulative Watershed Effects (CWE) Process, and agency planning documents, as well as Citizen Volunteer Monitoring data, are examples of types of data that would be considered Tier II. This type of information is used in 305(b) reports, subbasin assessments, and TMDL development.

Tier III

The scientific rigor of Tier III data often includes information collected by unknown or untrained individuals. The data may not have been collected or analyzed following standard or reported protocols. Data without any originating documentation also appears in this category. Relevance of data is limited due to information having no intrinsic judgment or known reference for comparison. The data may have been extrapolated based on other sites, or a reflection of a specific localized condition not representative of the water body.

This type of information may be considered as general background information, but it is not of sufficient rigor and relevance for listing decisions or regulatory actions.