In this study we assess for the first time the effectiveness of the policies used to address nutrient pollution in the Mississippi Atchafalaya River Basin (MARB) with a non-point source focus. These polices are based on cooperative federalism and thus give large autonomy and power to the states. This analysis provides a case study relevant to the management of water pollution in agriculturally-dominated watersheds worldwide.
•Agriculture drives poor water quality in the Mississippi, the largest U.S. watershed.
•The federal government determined individual states should address the issue.
•We assess the efficacy of the strategies implemented.
•There is uneven use of the best science and livestock pollution is not considered.
•The current approach is not effective in addressing water quality issues.