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Current Issues Regarding Gathering, Screening, and Interpreting Water Quality Data and Related Information in the Context of Section 303(d) of the Clean Water Act

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Though included in the original 1972 federal Clean Water Act, the Section 303(d) listing program lay dormant for nearly two decades. Since the early 1990s, EPA and the states have been struggling, despite having significantly less than ideal amounts of human and financial resources, to carry out this challenging program in a manner consistent with the letter and spirit of the law. (For instance, most states have not been able to assess the condition of more than half their surface waters.) In the early years of program implementation, the focus was on simply putting together the CWA–mandated lists of “water quality-limited waters” (defined in EPA regulations as those waters failing or, at immediate threat of failing, to meet one or more state applicable water quality standards)1 by April 1 of every even-numbered year.

Since the beginning of the 21st Century, the actual contents of 303(d) lists have come under increased scrutiny. Both citizen environmental advocacy groups and representatives of facilities and activities thought to be sources of pollutants causing failure to attain WQS have been paying increasing attention to proposed changes in 303(d) lists, and to the policies and practices upon which states base such lists. And, if these organizations are not satisfied with a state's responses to their comments, they often carry their concerns forward to US EPA, which under the CWA has a mandatory duty to review and approve or disapprove state 303(d) lists. If not happy with EPA's decisions, some stakeholders have exercised their right to challenge the Agency's decisions in the federal courts.

This article provides an overview of CWA statutory language, EPA regulations, and EPA guidance documents pertaining to the central elements of 303(d) listing: 1) gathering of chemical, physical, and biological data regarding the condition of waterbodies, as well as water quality-relevant information about natural and manmade features of their watersheds; 2) screening of available information to ensure it was collected in a scientifically sound manner and is representative of waterbody conditions of relevance to determining WQS attainment status; 3) using such data and information to provide credible estimates of actual waterbody conditions; and 4) comparing those estimated waterbody conditions to the desired conditions specified in state WQS.

In addition, the author of the article seeks to highlight some of the technical matters and policy issues that have emerged in recent years that the author finds particularly intriguing. Rather than trying to provide definitive answers to the questions raised by these topics, the author strives to elucidate the sometimes conflicting imperatives faced by the state and federal agencies charged with implementing Section 303(d) listing, and to pose questions designed to stimulate thought and discussion about how to deal with these dilemmas.

Keywords: 303(d) listing; Section 303(d); assessment methods; water quality standards; water quality standards attainment determination

Document Type: Research Article


Publication date: January 1, 2011

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  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

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