Over the past fifty years, the United States has realized substantial progress in addressing water pollution from industry, sewage treatment plants, and other end-of-pipe or ‘point’ sources of water pollutants. Much of this progress can be credited to the Federal Water Pollution Control Act Amendments of 1972, subsequently amended and known as the Clean Water Act (CWA). The CWA contains several noteworthy provisions, including effluent permits and technological requirements for point sources, mandatory development of water quality standards, and federal construction grants for publicly owned treatment works (POTWs).
Most water resources managers, scientists, and other experts would agree that nonpoint source pollution is a more pressing and challenging national water quality problem today than point source pollution. Nonpoint sources of pollutants include parking lots, farm fields, forests, or any source not from a discrete conveyance such as a pipe or canal. Of particular concern across the Mississippi River basin (MRB) are high levels of nutrient loadings—nitrogen and phosphorus—from both nonpoint and point sources that ultimately are discharged into the northern Gulf of Mexico (NGOM). Nutrients emanate from both point and nonpoint sources across the river basin, but the large majority of nutrient yields across the MRB are nonpoint in nature and are associated with agricultural activities, especially applications of nitrogen-based fertilizers and runoff from concentrated animal feeding operations. High inputs of nutrients from the Atchafalaya and Mississippi Rivers to the NGOM contribute to nutrient overenrichment and the creation of a seasonal zone of hypoxic (oxygen-deficient) waters, the extent of which is seasonally variable and that sometimes covers 20,000 square kilometers.
The federal-state interagency Mississippi River/Gulf of Mexico Watershed Nutrient Task Force in 2001 established a goal of reducing the hypoxic zone to 5,000 square kilometers by the year 2015—a goal that was restated in a 2008 updated report from the Task Force (USEPA, 2001, 2008). A 2007 report from the U.S. Environmental Protection Agency’s (EPA) Science Advisory Board stated that if the hypoxic zone is to be reduced to the 5,000 square kilometer goal, a 45 percent reduction in both riverine nitrogen and riverine phosphorus must be achieved (USEPA, 2007). For several statutory, scientific, financial, and other reasons, however, programs aimed at improving MRB-NGOM water quality have seen only limited progress to date and the hypoxic zone has continued a general trend of increasing areal extent when it is measured each summer. For example, the areal extent of the hypoxic zone in August, 2010 was measured at roughly 20,000 square kilometers (LUMCON, 2010).
This report from the National Research Council (NRC) Committee on Clean Water Act Implementation Across the Mississippi River Basin was sponsored by the U.S. Environmental Protection Agency and it offers strategic advice and priorities for addressing MRB and NGOM water quality management and improvements (see Box 1-1 for the committee’s full statement of task). In some areas, this report refers to and builds upon previous NRC studies on the Clean Water Act and Mississippi River basin and NGOM water quality (NRC, 2008 and 2009). Those reports note the limited authority of the EPA under the Clean Water Act to achieve the goals stated by the Task Force and the EPA Science Advisory Board. Although there is considerable uncertainty as to whether national water quality goals can be fully realized without some
fundamental changes to the CWA, there is general agreement that significant progress can be made under existing statutory authority and budgetary processes. More details of the findings and recommendations from those reports are listed in the main body of this report (especially see Box 1-2 for a listing of key findings and recommendations from the reports, which provide detailed advice to EPA, USDA and others regarding water quality monitoring and evaluation, nutrient criteria development, and nutrient control activities).
This Summary presents findings and recommendations from the four sections of this report that identify priority areas and offer recommendations to EPA and others regarding priority actions for Clean Water Act implementation across the Mississippi River basin. These sections are: USDA’s Mississippi River Basin Healthy Watersheds Initiative; Numeric Water Quality Criteria for the northern Gulf of Mexico; A Basinwide Strategy for Nutrient Management and Water Quality; and, Stronger Leadership and Collaboration.
USDA’s Mississippi River Basin Healthy Watersheds Initiative
In 2009, the U.S. Department of Agriculture (USDA) announced the establishment of its Mississippi River Basin Healthy Watersheds Initiative (MRBI). This is a four-year, $320 million program targeted at 41 watersheds across the Mississippi River basin designed to promote improvements in nutrient management and water quality. The program has attracted national-level attention and it holds great potential. The USDA and its Natural Resources Conservation Service (NRCS) deserve recognition for its development and establishment.
To be effective, any long-term strategy for improving MRB and NGOM water quality will support and promote collaboration among the states and federal agencies with major MRB and NGOM water management responsibilities. Given its Clean Water Act authorities and responsibilities, close collaboration with the U.S. Environmental Protection Agency will be essential. The importance and value of USDA and EPA coordination on these issues are explained in detail in NRC, 2009. Other federal agencies have important responsibilities in MRB and NGOM water quality monitoring and management, but because EPA is charged with protection of the nation’s water quality, stronger USDA-EPA collaboration will be essential to future and sustained MRB and NGOM water quality improvements (see also NRC, 2008).
The 2009 NRC report recommended establishment of a Nutrient Control Implementation Initiative, or NCII, and some aspects of the MRBI parallel the proposed NCII. The rationale for the NCII recommendation was to establish a systematic program for promoting improvements in technical validation, institutional model development, and socioeconomic viability. Along with water quality improvements, the NCII would strengthen agricultural and conservation intelligence. EPA support in the MRBI could promote research and learning to be used in future management decisions and as part of a long-term, adaptive process of MRB nutrient management.
The U.S. EPA should explore ways in which the agency can support activities related to MRBI evaluation. Ways in which EPA might assist include:
- identifying measures of progress;
- gauging the cost effectiveness of various nutrient control actions;
- assisting with MRBI project evaluation; and,
- establishing water quality monitoring projects and indicators of progress.
Numeric Water Quality Criteria for the Northern Gulf of Mexico
The establishment of numeric nutrient criteria for NGOM waters would represent a goal for the entire Mississippi River basin. Establishing numeric criteria for the northern Gulf would allow EPA and the Mississippi River states to begin working upstream in this large, complex watershed and provide an end point that could serve as the basis for nutrient load allocations throughout the basin. Moreover, implementing numeric nutrient criteria in the federal waters of the northern Gulf of Mexico could provide EPA with leverage when encouraging or mandating establishment of state numeric nutrient standards. Establishment of NGOM numeric nutrient criteria also would complement the MRBI in moving toward a more systematic and coordinated basin-wide approach to managing nutrients and water quality.
To reaffirm and reemphasize a recommendation from the 2008 NRC report, the EPA should establish numeric criteria for nutrients for the waters of the northern Gulf of Mexico.
A Basinwide Strategy for Nutrient Management and Water Quality
Although there have been some federal and state efforts to coordinate nutrient management and related water quality programs across the Mississippi River basin, interagency efforts to date have not produced a rigorous, action-oriented plan for reducing nutrient loadings. There is no comprehensive MRB-NGOM program that includes, for example, interim water quality goals to be achieved over a specified time horizon, nutrient load allocations across the basin’s tributary watersheds, a plan for more systematic data collection and analysis, or a framework of accountability to ensure achievement of goals and deadlines.
Development and implementation of a basinwide strategy would build on both the MRBI and the establishment of NGOM numeric nutrient criteria. Ultimate success of such a strategy will depend upon participation and commitments of several federal agencies and many states. Participation of states that have watersheds of high nutrient yields—which are primarily those states located along the Mississippi and Ohio Rivers—will be especially important. Nevertheless, a more comprehensive and definitive strategy is needed to provide guidance, establish priorities, set milestones, and track progress toward achievement of numeric standards.
The EPA, its partner federal agencies, and the Mississippi River basin states—especially the states along the Mississippi and Ohio rivers—should develop a more action-oriented basinwide strategy to address nutrient-related water quality problems throughout the Mississippi River basin and northern Gulf of Mexico.
Stronger Leadership and Collaboration
Achieving sustained reduction of the areal extent of NGOM hypoxia is a challenge that transcends the mandate and resources of any single government agency. The current framework of mainly voluntary coordination of actions and programs, although useful for promoting dialogue and raising awareness of water quality issues, has not realized substantive accomplishments in terms of on-the-ground project implementation or documented improvements in water quality. Lasting solutions to MRB-NGOM water quality problems will require stronger inter-agency collaboration and sustained support from the Administration and the U.S. Congress than have been exhibited to date.
The EPA, its partner federal agencies, the Congress, the Administration, and the Mississippi River basin states should provide a stronger, more coordinated commitment in order to develop long-term, adaptive, collaborative actions for effectively addressing water quality problems across the MRB and into the NGOM.
