particularly in the 10 mainstem states, is crucial. Coordination among other federal agencies is also necessary, because the U.S. Army Corps of Engineers (USACE) and the U.S. Geological Survey (USGS) have CWA-related programs and responsibilities along the river, and the National Oceanic and Atmospheric Administration (NOAA) has some water quality monitoring responsibilities in the Gulf of Mexico.

This chapter examines programs under the Clean Water Act in which federal, interstate, and state-federal coordination is needed for effective water quality protection in the Mississippi River. It examines existing and potential collaborations among states, EPA regions, and other federal agencies pertaining to Clean Water Act implementation, and the experience of various organizations that have been established to facilitate state and federal coordination on other shared U.S. waters. Finally, the chapter assesses the potential for using some of the approaches adopted by these organizations as models for improving Mississippi River water quality management.

As this report has explained, the pillars of the Clean Water Act are effective National Pollutant Discharge Elimination System (NPDES) point source permitting programs that achieve best available treatment technology; water quality standards comprising designated uses and water quality criteria; adequate monitoring to ensure protection of water quality and achievement of water quality standards; assessment to evaluate water quality status; and restoration programs to improve waters with impaired water quality relative to designated uses. For interstate rivers, coordination among states is important for effective implementation of each of these Clean Water Act components.

Water quality standards are central to Clean Water Act implementation. As explained earlier in this report, states develop standards for particular waterbodies that consist of use designations and criteria for the waterbody’s physical, chemical, and biological quality. States and the EPA use these standards to establish water quality-based effluent limitations for point source discharges, to assess surface water quality, and to develop restoration programs, based on TMDLs, for waterbodies that do not meet standards. Different use designations and associated water quality criteria established by different states for the same shared waterbody can lead to conflicts in permitting, monitoring programs, assessment conclusions, and restoration strategies.

Monitoring programs that both state and federal agencies administer are critical to the ability to determine the extent to which surface waters are meeting relevant water quality criteria, to understand trends and existing