Nonpoint source pollution measures in the Clean Water Act have no detectable impact on decadal trends in nutrient concentrations in U.S. inland waters

• DOI: 10.1007/s13280-023-01869-6
• Publication Date: 2023-06-23T23:28:44Z
• Authors: Nathan Tomczyk; Laura Naslund; Carolyn Cummins; Emily V. Bell; Phillip Bumpers; Amy D. Rosemond
• Keywords: Clean Water Act; Nutrient pollution

The Clean Water Act (CWA) of 1972 regulates water quality in U.S. inland waters under a system cooperative federalism which states are delegated implementation and enforcement authority CWA provisions by the Environmental Protection Agency. We leveraged heterogeneity state to evaluate efficacy its nonpoint source reducing nutrient pollution, leading cause impairment waters. used national survey data estimate changes concentrations over decade evaluated effect state-level policy implementation. found no evidence support an (i) grant spending on pollution remediation, (ii) criteria development, or (iii) monitoring intensity 10-year trends concentrations. These results suggest that current federal paradigm for improving is not creating desired outcomes.