States are required under the Clean Water Act (CWA) Section 303(d) to compile a list of waters that do not support their designated beneficial uses and submit the list in a biennial Integrated Report to the Environmental Protection Agency (EPA) for approval. Beneficial uses include drinking water, recreation, aquatic life, and agriculture.The 303(d) list identifies the pollutant(s) causing the impairment and prioritizes the development of Total Maximum Daily Loads (TMDLs) to meet state water quality standards and support beneficial uses.
The draft assessment methodology document describes Utah’s assessment methods for the 2022 IR cycle. The document complies with federal regulations that require states to evaluate all existing and readily available data against both narrative and numeric criteria when developing their 303(d) lists.
The Draft 2022 IR Assessment Methods document was open for a public comment period (174 KB) from January 20, 2021, to February 26, 2021. Any comments on assessment methods received after the close of the comment period are considered out of scope for the 2022 Integrated Report. DWQ has reviewed the feedback submitted during the public comment period and provided a formal response to comments along with the final assessment methods for the 2022 Integrated Report.
Final 2022 303(d) Assessment Methods – Changes from previous version and draft
|Section||Subsection||Page Range||Timing of Change||Nature of Change|
|Assessment Process and Time Frames||Developing the Methods/Public Review of the Methods Process and Schedule||16||Draft 303(d) Methods||Edits to timing details for 2022 Integrated Report.|
|Scope of the Assessment||Waterbody Types||24||Response to Comments||Edits to language describing river and stream waterbody type.|
|Scope of the Assessment||Assessment Units||25||Draft 303(d) Methods||Removed a section on required datums used for assessment unit shape files. Changed AU stream mileage estimation to perennial stream miles only.|
|Data Quality||Credible Data Matrices||30-31||Response to Comments||Changed calibration and sonde requirements to reflect sonde specifications typical of equipment used by DWQ staff and other water quality monitoring entities.|
|Data Submission Process||Period of Record||35||Draft 303(d) Methods||Changed to reflect current POR and our plan to incorporate accepted data from the 2018/2020 IR within the 2022 POR.|
|Assessments Specific to Flowing Surface Waters of the State and Canals||Conventional Parameter Assessments||38||Response to Comments||Stream grab samples are now assessed against the instantaneous minimum criteria (under the assumption early life stages are present for 3A and 3B waters) rather than the 30-day average criteria.|
|Assessments Specific to Flowing Surface Waters of the State and Canals||Conventional Parameter Assessments||39-43||Draft 303(d) Methods||Changed the percent exceedance language. Now, we calculate a percent exceedance based on the number of samples (or averages) exceeding the criterion divided by the total number of samples. Details therein.|
|Assessments Specific to Flowing Surface Waters of the State and Canals||Nutrient Assessments Specific to Headwater Streams||43-47||Draft 303(d) Methods; Response to Comments||New method. Edited language from draft 303(d) methods to better reflect EPA approval letter and added the approved decision matrix to the text.|
|Assessments Specific to Flowing Surface Waters of the State and Canals||Narrative Standards: Biological Assessments||48-49||Response to Comments||Updated links, removed sentence describing how other states use O/E.|
|Escherichia coli Assessment for All Waters||Data Preparation||66-72||Draft 303(d) Methods||Changed percent exceedance language in Scenario A to be consistent with conventional parameter assessments section.|
|Narrative Standards for All Waters||Harmful Algal Blooms (HAB)||74||Draft 303(d) Methods||Assessments on hold.|
|Appendix 1||Priority Parameters||97-104||Draft 303(d) Methods||Added Headwater Numeric Nutrient Criteria parameters and noted the hold on HAB assessment parameters.|
|Appendix 6||EPA Delisthing Codes||118||Draft 303(d) Methods||Updated EPA Delisting Codes|
|Appendix 8||Response to comments||120||Response to Comments||Added comment/response matrices to methods.|