Workshop participants engaged in wide-ranging discussion about water quality monitoring and evaluation along the Mississippi River and across the basin over the two days of the program. Some of those themes were discussed repeatedly and were of high future priority to workshop participants. The themes summarized in this section, in the committee’s view, stood out as future water quality monitoring and evaluation priorities identified by the participants. These themes are not ranked.
Managing nutrients across the Mississippi River basin and achieving related water quality goals is a tremendous challenge on several scales of both space and time. There is much to be learned about the overall system in order to determine the most effective actions to implement. Monitoring of land, water, and human activities on the land and water is critical to developing this knowledge.
The USDA/NRCS Mississippi River Basin Healthy Watersheds Initiative (MRBI) is built upon action-oriented monitoring and evaluation. Along with its achievements and values (including project implementation and a commitment to promoting more active water quality monitoring to assess project outcomes), the MRBI experience has highlighted challenges associated with realizing short-term water quality changes and improvements with discrete management projects. The 2009 NRC
report noted that it often takes many years—often at least ten years—to realize statistically significant water quality results from a given land or nutrient management project or action (NRC, 2009). Identifying nutrient and land management practices that support improvements in water quality is a long-term endeavor that will entail sustained monitoring initiatives in tandem with nutrient management actions. This dual “action-learning” strategy was recommended in the 2009 NRC report and via its recommendation for the Nutrient Control Implementation Initiative (NCII). This spirit of action-oriented learning also is reflected in the USDA NRCS Mississippi River Basin Healthy Watersheds Initiative. The MRBI is a prominent example of pairing nutrient management actions with monitoring activities to improve understanding of system responses.
Much has been learned from long-term monitoring in the Mississippi River basin, primarily at U.S. Geological Survey monitoring sites. The USGS has partnered effectively with states for operation and maintenance of many water quality monitoring stations. As the number of USGS monitoring sites has declined due to budget reductions, in some instances states have been able to step in to keep some sites operating. More long-term monitoring sites will help improve understanding of nutrient sources and nutrient fate and transport across the basin.
Long-term monitoring also is important for field evaluation of conservation practices. Plans for edge-of-field or watershed-scale monitoring will be more effective to the extent they can be conducted for several years in order to evaluate performance of conservation practices under a sufficiently broad range of inter-annual variability.
Interpretation and modeling of water quality data are greatly aided by complementary data on environmental conditions at the time of sampling (e.g., temperature, flow, and precipitation). As was pointed out by many workshop participants, more routine collection of such data in water quality monitoring plans would strengthen the overall water quality database for the basin.
Development and implementation of consistent methods and protocols for evaluation of water quality and conservation practices has enabled significant advances in basin-level analysis and modeling. Continued effort for standardization of methods is challenging but will be critical to the value of these studies.
Several workshop participants noted the value of “paired watershed” studies, which have documented benefits of improved nitrogen fertilizer
management practices and wetland restoration on water quality (e.g., in Iowa and Illinois). Conducting watershed-scale studies with adequate controls for comparison is challenging, but an important part of study design and in reliability and validity of results. Paired watershed studies were mentioned by many workshop participants as effective for accelerating the adoption of conservation practices that improve water quality. They also provide useful data for evaluation and improvement of watershed scale agricultural water quality models. Workshop participants generally supported expansion of the number of paired watershed studies in the Mississippi River basin.
Several workshop participants noted the importance of monitoring system design, and in this context it is useful to distinguish management-level monitoring and research-grade monitoring. Although research monitoring establishes methods and protocols, the level of detail is often not feasible or useful for larger-scale, management-level needs.
Results of on-farm demonstrations, pilot projects and paired watershed studies are documented using a variety of water quality monitoring techniques. Sophisticated techniques include continuous storm-based monitoring of discharge and pollutant concentration data with H-flumes and ISCO samplers. It is challenging to monitor pollutant losses during winter months because of ice and snow, yet losses can be important during these periods. Less sophisticated water quality monitoring often is conducted using grab samples, for example, which may provide inaccurate estimates of pollutant loadings during storm events. Sensor technology is evolving and improving rapidly.
Workshop participants noted the great potential regarding development and deployment of simple, reliable, and inexpensive water quality monitoring equipment for use by farmers. Simple monitoring equipment could provide more localized feedback to farmers about the water quality impacts of their farming practices on specific fields. If such simple approaches were available, farmers would better understand how much sediment, phosphorus, or nitrate they are losing from their fields and could better target and evaluate alternative practices.
Many workshop participants noted that a longstanding challenge to advancing understanding of the effectiveness of soil and water quality conservation practices in agriculture is acquisition of detailed knowledge about what landowners actually are doing on their property. There have been relatively few research studies in which land management practices have been intensely monitored and documented. Information about timing and rate of fertilizer application, for example, is critical for under-
standing performance of measures aimed at limiting nutrient inputs to or retaining nutrients within watersheds. Innovative approaches are needed to enable more accurate and extensive monitoring of land management practices in relation to soil and water conservation efforts. There are successful examples upon which to build. Jerry Hatfield of the USDA-ARS cited several examples, including studies in the Raccoon River Watershed for which detailed data on land practices have been collected. The study design included farmer production buyouts for two years for monitoring of tile drainage systems.
Advances in satellite remote sensing have facilitated better assessment of changes in land management. Whereas older technology (e.g., Landsat) has a spatial resolution of 30 meters and a return frequency of 15 days, newer satellite technology (e.g., Worldview) has a spatial resolution of 1.1 meters and a return frequency of 1.1 days (Mulla, 2013). The National Agricultural Statistics Service (NASS) has taken advantage of newer satellite technology to issue high resolution Cropland Data Layer (CDL) information that can be used to make accurate assessments of change in land management over time (Wright and Wimberly, 2013).
In the current regulatory structure, the study and implementation of conservation practices requires the voluntary cooperation of owners of private land. Conservation agencies have worked in this context for many years. Implementation and assessment of conservation practices has often been impeded by inadequate knowledge of activities on private property, due to limited or no access and/or variable levels of landowner cooperation. Workshop discussants noted that, at the same time, there remains inadequate understanding of what motivates landowners to cooperate, how levels of cooperation vary with socio-economic status, size of operations, and other factors. To the extent that implementation and effectiveness of conservation practices will continue to be dependent on voluntary cooperation, it is important that behavioral factors governing voluntary cooperation be better understood. There are great opportunities for additional studies and research and that can take the form of polls of farmer attitudes, perceptions, and priorities regarding nutrient reduction practices (see Arbuckle, 2013), models of economic choice and preference, and how rates of adoption vary across among various agricultural and conservation practices.
The need and desire of agricultural producers for better information about water quality conditions, and practices that may support improved water quality conditions, was described by some workshop speakers. This articulates the value in further exploring public communication strategies
and messages to better understand how to encourage stronger engagement on water quality issues. It also would be useful to better understand how to apply and learn from results from effective land use and nutrient management actions.
Models are used to interpret water quality monitoring data and are thus critical for any monitoring program. Modeling exercises and results also are a useful complement to data collection. For example, areas that are remote or otherwise difficult to access (e.g., hilly terrain) present challenges for implementing data collection stations or collecting samples, and data collection always will have some limits.
There are many different kinds of water quality models, from simple conceptual models to quantitative, process-based models that can consider loads and concentrations in domains of different scales. Process-based land-water interaction models in common use, such as the SWAT, APEX, and EPIC models (referenced earlier), are useful for identifying sources of pollutants, evaluating the effectiveness of conservation practices, identifying optimal locations to target for conservation practices, and identifying factors responsible for temporal changes in water quality. The statistical land-water interaction model SPARROW from the USGS (Alexander et al., 2008) has been used for identifying watersheds that contribute the largest pollutant loads and for assessing the causal factors for these loadings. Models focused on in-stream water quality, such as HSPF (Singh et al., 2005), are useful for establishing load allocations to point and nonpoint sources, but are less useful in evaluating the effectiveness of agricultural practices, or factors responsible for trends.
There was some discussion among workshop participants about building models that can help bridge from small scale to large watershed scale. Currently, “mechanistic” models are limited to small scale, and several participants mentioned the need to build mechanistic models that can “scale up” to the larger, watershed scale.
To assist design and implementation of monitoring programs at the watershed and basin scales, additional process models that can be advantageous at larger scales would be helpful. To date process-based models for land-water interactions largely have been focused at the field and small-watershed scale; additional attention on process-based models at the large-watershed and basin scale would complement the field and watershed-scale efforts. To represent the diverse processes and pathways for pollutant transport that operate across scales and to account for the changing importance of differing drivers across scales, routine model
refinement, as new production approaches and land management practices are developed, would be useful.
A range of water quality models has been developed for different scales and purposes in the Mississippi River states. There often are inconsistencies in these models across states and agencies that use them for evaluations of nutrient management and water quality. Stronger collaboration among federal agencies, states, and university scientists in determining models appropriate for certain kinds of common applications, could bring more consistency to monitoring data evaluation efforts and support a more systematic approach to water quality assessments for the basin. Some workshop participants suggested the value of a “modeling collaborative” for the Mississippi River basin that could discuss these inconsistencies, the need to better link smaller- with larger-scale spatial models, and other applications issues and challenges. Further, there may be opportunities for this collaborative group to broaden its scope, and to include models of economics and social behavior and (for example) how they might interface productively with models of physical systems.
The Mississippi River Basin Task Force Monitoring Collaborative is an initiative that includes compilation of nutrient monitoring data from federal and state agencies. Criteria have been established for data screening, and data are categorized in various ways. This effort provides a foundation of available data. Many workshop participants noted that the Water Quality Data Portal, an initiative of the USGS and the EPA, is providing a useful vehicle for data sharing. The USGS and EPA team is working with the USDA to include their water quality data.
More and better coordinated interstate and interagency collaboration in monitoring is fundamental to consistent and efficient monitoring programs, particularly for large rivers that form boundaries between states.
Workshop participants noted the limited interstate coordination in the Mississippi River basin on issues relating to hypoxia in the Gulf of Mexico. The Upper Mississippi River Basin Association (UMRBA), the Ohio River Valley Water Sanitation Commission (ORSANCO), and the Lower Mississippi River Conservation Committee (LMCRCC) are coordinating organizations, but their missions, authorities, geographic extent, and levels of resources all differ from one another. The result is no real interstate, basin-wide organization on water quality monitoring and evaluation. These circumstances were described in the 2009 NRC report, which presented a recommendation to create an interagency, interstate Mississippi River Water Quality Center (NRC, 2009).
The 2008 NRC report also offered several recommendations regarding interstate collaboration as it relates to water quality monitoring and evaluation. Given the prominence of this theme at the November 2013 workshop, some of those recommendations merit repeating here:
- The lower Mississippi River states should strive to create a cooperative mechanism, similar in organization to the UMRBA, in order to promote better interstate collaboration on lower Mississippi River water quality issues.
- There is a clear need for federal leadership in system-wide monitoring of the Mississippi River. The EPA should take the lead in establishing a water quality data sharing system for the length of the Mississippi River.
- The EPA Administrator should ensure coordination among the four EPA regions along the Mississippi River corridor so that the regional offices act consistently with regard to water quality issues along the Mississippi River and in the northern Gulf of Mexico.
- The EPA should encourage and support the efforts of all 10 Mississippi River states to effect regional coordination on water quality monitoring and planning and should facilitate stronger integration of state-level programs. (NRC, 2008, pp. 11-12)
The Gulf of Mexico Hypoxia Task Force 2008 Action Plan identified a number of specific actions to be taken. Participating states have presented various plans to help extend nutrient monitoring efforts. During the workshop it was noted that several states are in the process of developing nutrient reduction strategies, and some participants wondered at what point states will be prepared to observe and evaluate possible changes in water quality.
Workshop participants also noted the growing interest in nutrient trading, and the exploration of nutrient trading along the Ohio River by ORSANCO in partnership with the Electric Power Research Institute. Participants felt that nutrient trading schemes offer promise for nutrient management, but will require reliable, targeted monitoring for implementation. Nutrient trading activities would provide further impetus for coordination and a systems view for design of monitoring systems for the Mississippi River basin.
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