Water Quality Assessment

The Water Quality Assessment Program is responsible for ensuring that Wyoming remains in compliance with the federal Clean Water Act (CWA) by preparing and submitting the Integrated 305(b) and 303(d) Report to the US Environmental Protection Agency on a biennial basis.

Section 305(b)

Section 305(b) of the CWA requires that each state prepare and submit a biennial report to EPA by April 1 of even numbered years. The report must contain a description of the navigable waters of the state for the preceding year, including the extent to which current conditions allow for the protection and propagation of a balanced population of shellfish, fish, and wildlife, and allow recreational activities in and on the water.

Section 305(b) also requires each state to report the water quality and the elimination of pollutants necessary for designated use support. Specifically, each state is to identify waters that do not meet the above condition and recommend strategies to achieve these objectives. Additionally, each state is to estimate the environmental impacts, economic and social costs, benefits, and the predicted timeline for project completion.

Lastly, Section 305(b) requires that the sources and extent of nonpoint source pollution in each state be estimated, including a description of the current program used to mitigate these pollutants and associated financial costs.

Section 303(d)

Section 303(d) of the CWA requires that states identify and list waters for which the effluent limits outlined in Section 301 are not effective in attaining designated uses.

Each state must submit a 303(d) list of impaired and threatened waters to EPA by April 1st of each even numbered year. EPA must review and approve or disapprove the 303(d) list within 30 days of submittal.

Section 303(d) also requires that states develop a separate total maximum daily loads (TMDL) for each pollutant/segment combination on the 303(d) list. Waters on the 303(d) list must be prioritized for TMDL development based on the severity of each pollutant/segment combination or listing.

Wyoming’s Integrated 305(b) and 303(d) Report combines the requirements of both reports into a single document and is available here. Previous versions of Wyoming’s Integrated 305(b) and 303(d) Report are available in the reports section of this site.