30 Years of Improvements in the Nation's Water Quality

Nov. 20, 2003
Study Evaluates Long-Term Effects of 1972 Clean Water Act

Using historical records and water quality data archived over the past 60 years, a new retrospective study evaluates the impact of the 1972 Clean Water Act on long-term water quality trends in the nations rivers and estuaries. Previously elusive answers to critical questions about the effectiveness of the regulatory requirements of the 1972 Clean Water Act were first offered as a peer reviewed study by the U.S. Environmental Protection Agency (EPA) Office of Water in Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment. Using data and information not included in the agency report, John Wiley & Sons published Municipal Wastewater Treatment: Evaluating Improvements in National Water Quality in 2002.

G. Tracy Mehan III, EPA's Assistant Administrator for Water, commended the overall effort as being "the first national-scale study to provide a rigorous evaluation of the effectiveness of the effluent regulation policies in achieving the 'fishable and swimmable' goals of the Clean Water Act." The study supports the hypothesis that the 1972 Clean Water Act's technology-based regulation of wastewater treatment facilities has achieved significant nationwide environmental success. The researchers clearly demonstrated a "before and after" cause-effect relationship between the effluent limit regulations of the Clean Water Act, the national investment in water pollution control and significant improvements in water quality in the nation's rivers.

Under the Clean Water Act, the federal government invested more than $60 billion through the Construction Grants Program and the Clean Water State Revolving Fund to support the nations municipalwastewater infrastructure. The quantity of oxygen-demanding pollutants dumped into the nation's rivers by municipal wastewater plants decreased by 23 percent even while the nations population grew by 35 percent in the 30 years since passage of the 1972 Act. The effect of the dramatic decline in wastewater loading on water quality, particularly under critical low-flow conditions, was confirmed by statistically significant national-scale improvements in worst-case dissolved oxygen levels in more than two-thirds of the nation's watersheds and river reaches. The national investment in wastewater treatment by government and private industry has achieved significant improvements in water quality.

Mehan commended the findings of the study, noting that its nine case studies "make a compelling case that local water pollution control investments directly improved water quality, restored fisheries and other vital environmental resources, created water-based recreational opportunities and revitalized once abandoned waterfront property." Case studies include the Connecticut River, the Hudson-Raritan estuary, the Delaware estuary, the Potomac estuary, the James estuary, the Chattahoochee River, the Ohio River, the Upper Mississippi River and the Willamette River.

Although much has been accomplished, many rivers and estuaries still fail to meet the "fishable and swimmable" goals of the Clean Water Act. Nutrient enrichment, contaminated sediments, habitat and wetlands losses, pathogens and toxic chemicals continue to pose threats to human health and aquatic life. The job of restoring and protecting all surface waters is not yet complete. Environmental advocates must continue their vigilance to ensure that government agencies fulfill their responsibilities to restore and protect the valuable resources of the nations surface waters.

While celebrating the successes of the Clean Water Act, the authors warn that if water pollution control infrastructure investments fail to keep pace with future population growth, the environmental benefits realized over the past 30 years may be lost to the next generation.

Source: Dynamic Solutions LLC