This report summarizes presentations and discussions of Mississippi River and basin water quality management, monitoring, and evaluation programs that took place at a workshop that was held in St. Louis on November 18-19, 2013. The workshop was organized and moderated by the National Research Council (NRC) Committee on Mississippi River Water Quality Science and Interstate Collaboration. Members of the NRC committee structured the meeting agenda, identified and invited guest speakers (the meeting agenda is listed in this report as Appendix A), and authored the following report.
The November 2013 workshop and this report build upon several years of work by NRC committees on the topics of Mississippi River water quality, the Clean Water Act, and nutrient control actions. Committees of the NRC have issued three reports on these topics (see NRC, 2008, 2009, 2012):
- 2008: Mississippi River Water Quality and the Clean Water Act: Progress, Challenges, and Opportunities;
- 2009: Nutrient Control Actions for Improving Water Quality in the Mississippi River Basin and Northern Gulf of Mexico; and
- 2012: Improving Water Quality in the Mississippi River Basin and Northern Gulf of Mexico: Strategies and Priorities.
A consistent theme throughout these three reports is the critical importance of systematic and coordinated water quality evaluation and monitoring as a basis for improved scientific understanding of the links
between nutrient loads and water quality, and as an important step for nutrient management efforts that strive to improve water quality. Among their many findings, these reports have noted marked differences among water quality monitoring resources, personnel, the number of monitoring sites, and the setting of water quality standards in the ten states along the Mississippi River corridor. Those reports have encouraged stronger collaboration among these ten river corridor states in water quality monitoring activities, and also noted opportunities for a stronger role for federal agencies with water quality monitoring expertise and responsibilities.
To further complement the work of these previous NRC studies, a two-day workshop was convened to focus on science initiatives and challenges in Mississippi River basin water quality monitoring and evaluation. (Box 1-1 contains the statement of task for this report and that guided the structure of the workshop.) The workshop examined a wide array of challenges and progress in water quality monitoring and evaluation in states along the Mississippi River corridor, and provided a forum for experts from U.S. federal agencies, the Mississippi River states, nongovernmental organizations, and the private sector to share and compare monitoring and evaluation experiences from their respective organizations. The workshop was convened, and this report issued, as “stand-alone” products. At the same time, the National Research Council will continue to seek opportunities to organize studies or other activities to promote the science of water quality evaluation and monitoring across the Mississippi River basin and into the northern Gulf of Mexico, and to encourage the interstate collaboration that will be crucial to more systematic monitoring regimes and approaches for basin-wide monitoring.
There are a great many science and policy issues surrounding nutrient management and water quality issues across the Mississippi River basin and that extend into the northern Gulf of Mexico. These issues include implementation of Total Maximum Daily Load (TMDL) plans, risk management associated with management of reactive nitrogen, costs of nutrient management, the intersection of nutrient management and food production and security, nutrient management impacts on greenhouse gas emissions, and water quality trading. Any or all of these issues conceivably could be discussed in the context of Mississippi River water quality, and they all will need to be considered at some level for better management of nutrients and reducing effects on water quality across the Mississippi River basin. To provide a focused workshop and report, this project adhered closely to the scientific, monitoring, and evaluation issues described in its statement of task (Box 1-1), and did “… not make recommendations regarding budgets, resource management practices, or economic policies.”
Report Statement of Task
An ad hoc committee will issue a consensus report summarizing scientific challenges and priorities regarding Mississippi River water quality monitoring and evaluation.
The report will be based in large part on presentations and information gathered during a two-day public workshop. This event will include presentations that focus on the science behind understanding Mississippi River basin water quality conditions. The emphasis will be on the science and evaluation of water quality conditions, along with discussion and dialogue about these and other related issues. The geographical focus will be on the 10-state Mississippi River corridor and the northern Gulf of Mexico. The committee will develop the agenda, select and invite speakers and discussants, and moderate the discussions.
Goals of the two-day workshop include the following:
- promote basin-wide dialogue of current scientific understanding of water quality conditions,
- discuss scientific uncertainties, relevant issues of time and scale, and priority areas for future water quality monitoring and evaluation,
- discuss ongoing programs for nutrient management and downstream water quality implications,
- discuss institutional frameworks for future water quality evaluation and administration, and
- provide a platform for future discussion, collaboration, and learning of water quality conditions and changes along the Mississippi River and across the river basin.
Following the workshop, the committee will convene an additional meeting at which it will prepare a brief consensus report that provides the committee’s conclusions regarding scientific challenges and priorities for Mississippi River water quality monitoring and evaluation. The report will not make recommendations regarding budgets, resource management practices, or economic policies.
Financial support for the workshop and report was provided by The McKnight Foundation, the U.S. Department of Agriculture’s Natural Resources Conservation Service, the Walton Family Foundation, and the National Academies’ Presidents Fund.
Across the Mississippi River basin and into the northern Gulf of Mexico, issues associated with excessive loads of the primary nutrients nitrogen (N) and phosphorus (P)—and resultant water quality effects—
are of great interest and importance at local, regional, and national scales (Figure 1-1). Although necessary to support aquatic habitats and species, these nutrients often exist in excess concentrations as a result of high loadings from a variety of pathways and sources, including erosion, runoff and tile drainage of nutrient-rich soils, applications of fertilizer and animal manure, discharges of municipal and industrial water treatment plants, urban runoff, and atmospheric deposition. Excess nutrient concentrations have a variety of effects across a range of scales and include local water quality impairments, such as freshwater algal blooms in lakes and rivers, contamination of groundwater, and areas of hypoxic waters in marine coastal waters and estuaries, including the northern Gulf of Mexico. Understanding the sources and amounts of nutrient loading within the basin is a necessary predecessor for mitigation efforts that produce measurable improvements in water quality.
Agricultural producers, university scientists and extension experts, state and federal agencies, nongovernmental organizations, and the pri-
FIGURE 1-1 Mississippi River basin, major tributaries, land uses, and typical summertime extent of Northern Gulf of Mexico hypoxia (in red). The Mississippi River basin extends over 31 states and covers 41 percent of the conterminous United States.
SOURCE: NRC, 2009.
vate sector are engaged in an impressive array of nutrient management and water quality monitoring activities. States along the Mississippi River corridor, and across the basin, conduct TMDL assessments as required under the Clean Water Act. Prominent interstate bodies, such as the Ohio River Valley Water Sanitation Commission (ORSANCO) and the Upper Mississippi River Basin Association (UMRBA), support many initiatives designed to promote interstate collaboration on nutrients issues. Water quality concerns across the basin and into the northern Gulf of Mexico led to the establishment of the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force in 1997 with the participation of five federal agencies and 12 states in the basin. Several other federally sponsored activities have been implemented in the basin, including the U.S. Department of Agriculture’s Mississippi River Basin Healthy Watersheds Initiative (MRBI), and basin-wide water quality modeling by the U.S. Geological Survey in the agency’s “SPARROW” (Spatially Reference Regression on Watershed Attributes) studies (see Alexander et al., 2008).
The science of nutrients and water quality is concerned in large part with determining the levels of nutrient concentrations and loads that will impair water quality in fresh or marine waters, as well as helping define goals and management strategies that are appropriate for reducing nutrient levels and restoring ecological values and their associated uses. Assessment of water quality conditions typically is based upon a combination of water quality monitoring data, and evaluation of those data using watershed or field-scale modeling.
Nutrients are essential for aquatic life; however, it often is difficult to determine levels of “excessive” nutrient concentrations with precision. The difficulties of measuring effects of nutrients on ecosystems and species are complicated by the many variables that affect these relationships, which include factors such as water temperature, dissolved oxygen levels, turbidity, water velocity, light levels, sediment quality, presence of wetlands, and other characteristics and features. Further, the definition of an impaired water body is site specific, and depends in part on the desired condition or use of the water body (e.g., drinking water source, aquaculture, etc.) established by the relevant State/Commonwealth of jurisdiction, or tribe, under the Clean Water Act.
Other complications in establishing water quality monitoring regimes and protocols relate to design of the monitoring program and intended uses of data. It is not feasible to monitor and sample water quality at all points across or within a given water body or stream network. Thus, decisions have to be made about water quality monitoring strategies regard-
ing frequency of monitoring (daily, monthly, continuous, etc.); time of day; monitoring during, or after, storms; appropriate locations and depths to be monitored; and appropriate balance of samples from, for example, a river’s main channel and slower-velocity backwater areas. Moreover, and with regard to nutrient effects on downstream waters, statistically significant effects may not be measured for years or even decades. In addition, data needs for regulatory activities, such as TMDL assessments, and other uses such as contaminant fate and transport modeling, often need to be considered in designing monitoring programs.
Numerous federal, state, local, and private sector programs and activities have been established and are devoted to monitoring, evaluating, and modeling of water quality, and the effects of nutrients across the Mississippi River basin. All these activities of course have varying mandates, missions, and activities but portions of these programs are devoted to managing water quality and the implications of nutrient loads.
The following chapter includes summaries of presentations and discussions at the workshop, and text boxes that summarize two luncheon presentations. The report’s final chapter summarizes priorities and future opportunities in water quality monitoring, modeling, and evaluation as identified by workshop participants.