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Confronting the Nation’s Water Problems: The Role of Research 5 Data Collection and Monitoring The long-term monitoring of hydrologic systems and archiving of the resulting data are activities that are inseparable from the water resources research enterprise of the nation. Data are essential for understanding physicochemical and biological processes and, in most cases, provide the basis for predictive modeling. Examples of water resources and other relevant data that are collected through a variety of measurement devices and networks are: hydrologic storages and fluxes such as soil moisture, snow pack depth, precipitation, streamflow, hydraulic head, recharge, and evapotranspiration land-ocean-atmosphere energy fluxes water, land, and air quality measures, including physical, chemical, biological, and ecological elements water and energy demand, consumptive use, and return flows terrain elevation and land use, and lake, stream, and river geometry Data collection is the means by which these types of data are acquired for multiple uses, including for flood warnings and other health and safety monitoring activities, weather prediction, engineering design, commercial and industrial applications, and scientific research. Monitoring is data collection with the more targeted purpose of detecting and drawing attention to changes in selected measures, particularly extreme changes. Monitoring data have multiple applications. They may serve as indicators of health and safety risks, as trip wires for policy changes, or as the basis for research on variability and trends in hydrologic and related phenomena.
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Confronting the Nation’s Water Problems: The Role of Research The full dimensions of the challenges and opportunities associated with data collection and management for the hydrologic sciences have become evident in recent years. These issues are especially important for federal agencies because these agencies are instrumental in developing new monitoring approaches, in validating their efficacy through field studies, and in managing nationwide monitoring networks over long periods. This chapter is not a comprehensive assessment of water resources data collection activities. Rather, it is intended to highlight the importance of data collection and its role in stimulating and facilitating water resources research. Thus, it relies upon a few specific examples from certain federal agencies. As a consequence, not all data collection activities relevant to water resources research are included (e.g., active disease surveillance and monitoring of land use are not discussed), nor are all federal and state agencies that support or actively conduct monitoring mentioned. CHALLENGES IN MONITORING There are important challenges facing federal agencies that collect and manage hydrologic data. One of these challenges is related intrinsically to the types of problems for which hydrologic data are being used. For example, the analysis of problems related to floods and droughts requires specific information about extreme events, which can be developed only after conducting decades or even centuries of precipitation and streamflow monitoring across a variety of different climatic and hydrologic settings. Similarly, an assessment of the impact of global climate change on groundwater and surface water resources will require basic monitoring systems capable of providing data for time periods of centuries. With other problems, like nonpoint source contamination of streams resulting from runoff laden with nitrate, pesticides, and sediment, hourly data may be required because of the close association of stream contamination with the timing of storms and resulting runoff processes. In this case, the greater challenge is encompassing all relevant spatial scales, because the local variability in contaminant loading is related to changes in land use and farming practices. In general, the broad spectrum of present and future scientific water problems nationwide requires monitoring systems that function reliably over both large and small time and space scales. Unfortunately, as described in detail in later sections, observational networks to measure various water characteristics have been in decline during the last 30 years because of political and fiscal instabilities (e.g., NRC, 1991; Entekhabi et al., 1999). The following sections provide a detailed discussion of how several national monitoring networks have fared over time. The funding situation for monitoring networks is remarkably similar to that for research on improving data collection activities (Category VII), which Chapter 4 showed as having declined to a level that is only a fourth of its value in the mid 1970s. These facts point to
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Confronting the Nation’s Water Problems: The Role of Research the need for increased funding for in situ data networks as a necessary complement to water resources research activities. Unquestionably, the complexity of monitoring has increased dramatically as researchers have begun to sort out the interactions among physical, chemical, and biological processes in water (Pfirman and AC-ERE, 2003). Before 1960, hydrologic monitoring in the U.S. Geological Survey (USGS) emphasized streamflows, sediment transport, and groundwater levels. As problems of contamination became more evident, monitoring expanded to examine basic water quality variables. Now, monitoring encompasses a variety of anthropogenic compounds in water and sediment, aquatic organisms, and other biological characteristics. In just the past few years, advances in analytical techniques and the discovery of new, ecologically significant families of contaminants have made the need for comprehensive monitoring of aquatic systems even more evident. Federal agencies are under significant pressure to respond to the increasing need for chemical and biological monitoring of aquatic systems. The creation of the National Water Quality Assessment (NAWQA) program of the USGS high-lights the emerging importance of this type of monitoring, as well as its complexity and potential costs. Yet, even this large program is only a first step in providing the information necessary to support federal regulations related to water quality (e.g., the Total Maximum Daily Load program), to support restoration of aquatic ecosystems impacted by agriculture (e.g., the Neuse River basin), and to promote the sustainability of water resources (e.g., the Rio Grande). The development of the kind of enhanced chemical and biological monitoring that will be needed to address such issues remains a challenge. Complexity in monitoring also arises because of the scales at which problems are now manifested. For example, the study of hypoxia in the northern Gulf of Mexico is inexorably linked to the Mississippi–Atchafalaya River Basin, which drains an area of 3.2 million square miles (NSTC, 2000). New, scale-appropriate techniques will be required to examine hydrologic conditions across watersheds of subcontinental proportions. Unfortunately, such large-scale monitoring approaches are in their infancy and are not sufficiently developed to meet even immediate needs for some classes of problems. As will be discussed shortly, this challenge to provide new kinds of data is also an opportunity for innovative research related to space-borne and sensor technologies. The increasing variety and quantity of information coming from monitoring systems have created new problems of data warehousing and dissemination. Federal and state agencies over time have developed important databases (e.g., the Environmental Protection Agency’s [EPA] STORET and USGS’ NWIS) that are an increasingly useful way to identify problems and research needs. However, as a consequence of historical agency responsibilities and/or lack of national funding, federal water resources data are spread among different federal and state agencies with broadly different capabilities for supporting user needs and with different resources for making important legacy data available to researchers. Taylor and
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Confronting the Nation’s Water Problems: The Role of Research Alley (2001) point out that many state agencies have backlogs of data waiting to be summarized in electronic databases. (Indeed, one agency representative reported that summer students were used to develop web sites that can disseminate valuable historical data from research watersheds.) There is little consistency in federal and state programs for recovering the costs of monitoring. Some monitoring data (e.g., some stream discharge data) are freely available, while in other cases (e.g., Landsat), Congress has mandated cost recovery for the data, which makes using such data expensive in research and may limit their creative use. An important aspect of improving hydrologic data collection is to take into account the uncertainties associated with both data collection methods and the design of data collection networks. Hydrologic forecasting relies heavily on measurements of multiple hydrologic variables taken over long periods of time, particularly because low-frequency but high-magnitude events can have near-irreversible effects on water supply. As monitoring networks decrease in size and density, uncertainty increases. Methods of rescuing and augmenting the available data are needed to reduce the uncertainty of predictions. Similarly, methods of validating and estimating the uncertainty of remotely sensed data are needed, as these sources of data are becoming increasingly important in hydrologic analyses. OPPORTUNITIES IN MONITORING Hydrologists working in the United States can now take advantage of new monitoring data and new technical approaches for monitoring hydrologic processes. Important advances for the diagnosis and prediction of hydrologic processes have come from remote sensing using products derived from observations that span a wide range of the electromagnetic spectrum (e.g., visible, infrared, microwave) (Owe et al., 2001). For example, Landsat satellites have provided a significant record of land-cover conditions on the earth’s surface and an ability to monitor land-use changes (e.g., Running et al., 1994), and they can measure water clarity and chlorophyll in lakes (www.water.umn.edu). Remote sensing has also been shown to provide significant information about hydrologic extremes, such as drought, and to have the potential to enhance our ability to forecast these events (e.g., Kogan, 2002). New satellite sensors (e.g., Advanced Microwave Sounding Unit on the National Oceanic and Atmospheric Administration [NOAA] 15, 16, and 17 satellites) with the ability to penetrate cloud cover and produce land surface moisture products with temporal resolutions of hours and spatial resolutions of tens of kilometers promise to enhance our operational database that supports water supply forecasts (Ferraro et al., 2002). Chlorophyll levels in freshwater lakes now are being mapped routinely by satellite. Furthermore, high-resolution satellites are being used to map distributions of different types of aquatic plant communities in wetlands and littoral areas of lakes, and aircraft-mounted spectroradiometers are being used to map aquatic vegetation and water quality conditions (e.g., turbidity, phosphorus, and chlorophyll a) in rivers.
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Confronting the Nation’s Water Problems: The Role of Research Radar altimeters, like TOPEX/Poseidon and Jason-1, which have been used mostly for measuring changes in sea level, are also useful for measuring the stages of large rivers and lakes (Birkett, 1995, 1998). The laser altimeters aboard ICESat, although not particularly reliable at the present stage of development, have demonstrated the potential to measure water-surface elevations for small waterbodies on a regular basis. The Gravity Recovery and Climate Experiment (GRACE) mission provides unprecedented capabilities to assess changes in water storage over large regions (Rodell and Famiglietti, 1999, 2002). GRACE is anticipated to provide monthly measurements of total water storage anomalies with a spatial scale of longer than several hundred kilometers, and with an accuracy of a few millimeters in water-height change. Ground-based remote sensing monitoring systems have been developed that are applicable to water resources investigations of regional water supplies. A good example is the widespread national deployment of the WSR-88D weather radar (NEXRAD). Each NEXRAD station monitors thousands of square kilometers and provides almost continuous space-time estimates of precipitation with kilometer resolution (e.g., Klazura and Imy, 1993). When properly calibrated, these systems can provide highly resolved estimates of precipitation for complex storms or for regions where coverage by conventional gages is limited (e.g., Seo et al., 2000). Remote sensing will undoubtedly change the way that some hydrologic monitoring is carried out, although routine use of some of these technologies for water resources research is still years away. In the meantime, the use of the remotely sensed data for water resources research on regional and local scales will require validation and adjustment with legacy monitoring measurements and, for many applications, combined use with in situ measurements of longer records. For example, it is expected that detailed monitoring of chemical and biological conditions will still require sampling and laboratory analyses or in situ sensor measurements, and likely some combination of both. Fortunately, technological advances are being made in developing low-cost and reliable sensors and miniaturized in situ instruments to measure a wide variety of chemical and biological contaminants in natural waters (ASLO, 2003). In addition to requiring validation with legacy monitoring, profitable use of remotely sensed data will require measurements of associated space-time observation uncertainty. Such efforts are required because remote sensors in many cases do not directly measure the quantity of interest, because the data they generate carry biases due to atmospheric and land surface interference, or because their penetration depth into the land surface is shallow. In addition, regional and local databases of remotely sensed data in most cases have short record lengths that are often inadequate for the study of water supply variability, including climate extremes. It should be noted that remote sensing systems for some crucial water monitoring data—for example biological metrics of water quality like
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Confronting the Nation’s Water Problems: The Role of Research numbers and health of algae, invertebrates, fish, and aquatic and terrestrial plants—are only now being developed. Thus, although there is much progress with respect to remote sensing systems measurement and monitoring, important in situ monitoring systems are in decline without clear plans for transitioning to new or alternative technologies. Because of the “stovepiping” within agencies, there is no overall coordination in operating monitoring systems and in determining directions of new technological initiatives. A new paradigm for data acquisition and management is offered by the cyberinfrastructure view of information, which is a significant step for enabling the next generation of research in science and engineering. The National Science Foundation (NSF) is at the forefront of this important new initiative, which recognizes the ability of new developments in information technologies to change the way data are collected, managed, and used (Atkins et al., 2003). The term cyberinfrastructure refers to the variety of approaches (some new, some old) for the creation, dissemination, and preservation of knowledge. The NSF vision is “to use cyberinfrastructure to build more ubiquitous, comprehensive digital environments that become interactive and functionally complete for research communities in terms of people, data, information tools, and instruments” (Atkins et al., 2003). The development of these approaches is a bold step forward in the seamless integration of experimentation and data collection. The most important implication of cyberinfrastructure for water resources is that monitoring is not simply an isolated task but is part of an integrated information strategy that more directly connects researchers with data and the actual process of measurements. If properly executed, this strategy has the potential to create a more uniform technological vision among federal agencies and to reduce redundancies in data handling among federal agencies. In other words, there are opportunities for government agencies concerned with monitoring to develop a systemic approach to handling the explosion of new data and the operation and maintenance of monitoring systems. Federal agencies are relatively independent in their approaches and solutions to issues of monitoring and data management. STATUS OF KEY MONITORING PROGRAMS Addressing water resources concerns in the future will require increasingly sophisticated monitoring data. Streamflow data, for example, are necessary to (1) support important public policy decisions concerning towns located in the floodplains of rivers like the Mississippi, (2) engineer structures to limit flood damages from rivers like the Red River of the North, and (3) manage water resources in important western rivers like the Colorado. Chemical, biological, and sediment data are needed to evaluate the efficacy of attempts to restore water quality and ecological health in the Chesapeake Bay, the Mississippi River system, and the San Francisco Bay, which are being adversely affected by nonpoint source contamination. Global climate change is predicted to have major impacts
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Confronting the Nation’s Water Problems: The Role of Research on rivers of the northwestern United States and the Prairie Pothole region of the northern Great Plains (NAST, 2000) and will require new monitoring networks. The following sections provide examples of the national decline in some types of monitoring systems and the funding limitations that have stifled efforts toward new national systems in groundwater and soil-moisture monitoring. The lack of investment in hydrologic monitoring is hard to reconcile, given the societal cost and significance of problems affecting water resources now and in the future. The reasons for the decline are many and speculative. It is possible that the distributed nature of water resource problems and the long periods between extreme events have obscured the need for monitoring systems (i.e., it is too early to see the negative impacts of the cuts in monitoring). Alternatively, it may be that the consequences of dismantling or substantially reducing monitoring systems have been small to date because accumulated science and engineering knowledge has been able to cope to some extent with the uncertainties of reduced observations. Another possibility that might account for the observed decline is that there are likely fewer and less visible investments in large water resources structures (e.g., dams, reservoirs, canals, and reclamation projects) that might require data. The responsibilities for collecting, maintaining, and distributing hydrologic data remain with federal agencies, and this situation is not likely to change, given the nature of water resources data collection as a public good (see Chapter 1). The dilemma of the federal agencies is how to simultaneously maintain legacy monitoring systems, respond to escalating needs for expanded monitoring of all kinds, and take advantage of new opportunities in infrastructure development for measurement and data management. Streamflow The USGS has been collecting streamflow information since 1889 and today operates a national network of about 7,200 stream gages. The information provided by the network is used for many purposes, including water resource planning, daily water management, flood prediction and hazard estimation, water quality assessment and management, aquatic habitat assessment and mitigation, engineering design, recreation safety, and scientific research. Funding for the network comes from the USGS and over 800 other federal, state, and local agencies. This unique arrangement helps ensure streamflow information relevant to local needs; however, it also means that the USGS does not have complete control over the network, including the number or location of the individual stream gages that constitute the network. Stream gages with long periods of record are of great importance for estimating hydrologic extremes (floods and droughts) and for resource planning. These gages are crucial to describing and understanding the effects of climate, land-use, and water-use changes on the hydrologic system. However, maintaining stream gages with a long period of record is not always a priority of many partner agen-
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Confronting the Nation’s Water Problems: The Role of Research cies. As a consequence, there has been an alarming loss of stream gages with 30 or more years of record over the last three decades, even though the total number of stream gages in the network has remained relatively constant (Norris, 2000). In the period 1990–2001, 690 stream gages with 30 or more years of record were discontinued; nearly 170 of those were discontinued in 1995 alone. The USGS has described the instability of the national stream gaging network as being related to the current dominant funding process of stream gages and has proposed plans to modernize, stabilize, and fill critical gaps in the network (USGS, 1999; Hirsch and Norris, 2001). This plan, called the National Streamflow Information Program (NSIP), would provide for a stable nationwide backbone stream gage network that would be fully funded by the USGS to maintain for future generations the important long-term streamflow information at critical locations. Stream gages required for local needs would supplement this backbone network and would remain funded through the Cooperative Water Program. In addition to providing a stable component to the national stream gaging network, NSIP would also enhance the value of all streamflow information obtained by the USGS by improving and modernizing data delivery, obtaining more information during hydrologic extremes than is currently obtained, analyzing streamflow information to provide insights on key characteristics (e.g., long-term trends and their relationship to natural and anthropogenic features within watersheds), and conducting research and development aimed at improving instruments and methods in order to provide more accurate, more timely, and less expensive streamflow information in the future. According to NRC (2004), the NSIP program adequately takes into account both the spatial distribution (in terms of value and need) of gages and the use of modeling to provide information about ungaged locations. This is an ambitious program that would require a considerable long-term financial commitment from Congress and the executive branch. So far, only minor additional funding has been appropriated for this program. Groundwater Levels Water-level measurements from observation wells are the principal source of information about the effects of hydrologic stresses on groundwater systems. In recent years, the USGS and many state and local agencies have experienced difficulties in maintaining long-term water-level monitoring programs because of limitations in funding and human resources. A poll of USGS district offices and 62 state and local water management or regulatory agencies about the design, operation, and history of long-term observation wells in their respective states indicated that there are about 42,000 observation wells in the United States with five years (a relatively short period) or more of water-level record data (Taylor and Alley, 2001). About a quarter of those are monitored under the USGS Cooperative Water Program. The level of effort in collecting long-term water-level data varies greatly from state to state, and many of the long-term monitoring
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Confronting the Nation’s Water Problems: The Role of Research wells are clustered in certain areas. Although difficult to track, the number of long-term observation wells appears to be declining. For example, the number of long-term observation wells monitored by USGS has declined by about half from the 1980s to today (Alley and Taylor, 2001). Groundwater-level data become increasingly valuable with length and continuity of record. Ease of access to the data and their timeliness also are valuable, especially during periods of stress such as droughts. Although real-time surface water data have been available through the Internet for nearly a decade, the availability of real-time groundwater data is relatively new within the USGS. Between the years 2000 and 2003, real-time data for wells available through the Internet went from fewer than 300 wells (mostly in south Florida) to nearly 700 wells. Real-time data applications allow effective aquifer management, produce high-quality data, and can be cost-effective. As the availability and reliability of real-time groundwater data increase, so will their value to scientists and the public. Despite the existence of thousands of observation wells across the nation, most groundwater-level data collection is funded to address state and local issues. Yet, there is evidence that more groundwater problems are becoming regional or national in scale, as exemplified by interstate conflicts over groundwater sources becoming salinized or overdrawn. A case in point is the High Plains aquifer, which encompasses eight states in the central United States. In parts of Kansas, New Mexico, Oklahoma, and Texas, current groundwater withdrawals, primarily used for irrigation, are unsustainable because the natural recharge is low, resulting in a dramatic decline in groundwater levels (Alley et al., 1999). Given the increasing reliance on groundwater sources (Glennon, 2002), it is important to understand trends in groundwater levels and quality over large regions. Unfortunately, there is no comprehensive national groundwater-level network with uniform coverage of major aquifers, climate zones, or land uses. In fact, data on groundwater levels and rates of change are “not adequate for national reporting” according to the report The State of the Nation’s Ecosystems (H. John Heinz III Center, 2002). Data are not collected using standardized approaches at similar spatial or temporal scales, and the long-term viability of the data collection efforts is uncertain. Ideally, a comprehensive groundwater-level network is needed to assess groundwater-level changes, the data from which should be easily accessible in real time. Soil Moisture It has been long recognized that soil moisture in the first one or two meters below the ground surface regulates land-surface energy and moisture exchanges with the atmosphere and plays a key role in flood and drought genesis and maintenance (e.g., Huang et al., 1996; Eastman et al., 1998). Soil moisture deficit partially regulates plant transpiration and, consequently, constitutes a diagnostic
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Confronting the Nation’s Water Problems: The Role of Research variable for irrigation design (e.g., Dagan and Bresler, 1988). High extremes of soil moisture are associated with high potential for flooding and hazardous conditions. As the “state variable” of the vadose zone, soil moisture plays a key role in surface–subsurface water exchanges. Although the importance of soil moisture for hydrologic science and applications cannot be overemphasized, there are few long-term and large-scale measurement programs for soil moisture that provide in situ profile data suitable for hydroclimatic analysis and design in the United States (e.g., Hollinger and Isard, 1994; Georgakakos and Baumer, 1996) and abroad (e.g., Vinnikov and Yeserkepova, 1991). Active and passive microwave data from polar orbiting satellites or reconnaissance airplanes do provide estimates of surface soil moisture with continuous spatial coverage. However, they are limited in that they only measure soil moisture within the first few centimeters of the soil surface, and they are reliable only when vegetation cover is sparse or absent (e.g., Ulaby et al., 1996; Jackson and Le Vine, 1996). This lack of long-term soil moisture data over vast areas of the United States affects how well soil moisture is incorporated into hydrologic models for watersheds or large regions. At the present time, models must use estimates derived from secondary sources of information or from other models, rendering predictions pertaining to ecosystem behavior or surface water–groundwater interactions subject to significant uncertainty. Even a few long-term monitoring networks of soil moisture would substantially decrease the uncertainty in predicting processes that critically depend on soil moisture levels (like flow, water chemistry, and plant response). In a similar vein, the uncertainty of predictive models for managing water supply in western streams reflects the density of streamflow and rainfall monitoring networks, because the amount and the quality of data in areas characterized by high spatial variability in precipitation determine how reliable and precise such models can be. The development of a national soil moisture monitoring network is an essential element to conducting successful research on the physical, chemical, and biological processes in the surface layer of the continental United States. The U.S. Department of Agriculture (USDA) Natural Resources Conservation Service has established a coordinated national network of in situ measurements of soil moisture and soil temperature in support of agricultural needs (Soil Climate Analysis Network or SCAN). Although this is a step in the right direction, significant expansion of the network into nonagricultural areas together with a long-term commitment for high quality data are necessary for water resources analysis on climatic and regional scales. Furthermore, modeling and observational studies have shown substantial soil moisture variability over a range of scales (e.g., Rodriguez-Iturbe et al., 1995; Guetter and Georgakakos, 1996; Vinnikov et al., 1996; Lenters et al., 2000), and the development of a monitoring plan for soil moisture on the basis of both remotely sensed and on-site data is a requisite research endeavor that should account for such variability.
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Confronting the Nation’s Water Problems: The Role of Research Water Quality Water quality monitoring has seen declining trends in funding similar to those for streamflow and groundwater level monitoring. Both the EPA, through its Environmental Monitoring and Assessment Program (EMAP), and the states, through their delegated authority from EPA for the Clean Water Act, conduct some water quality monitoring. Unfortunately, efforts are inconsistent from state to state and are often inadequate, and some are in decline. Recent reports (e.g., GAO, 2000; NRC, 2002a; Mehan, 2004) cite the need for consistent ambient water quality data for purposes of Clean Water Act compliance. The current shortfalls and future needs are illustrated below using USGS water quality programs as examples. For some areas, USGS data are relied upon to establish trends in water quality over time and to compare conditions across local jurisdictional boundaries. Unfortunately, water quality monitoring networks within USGS have not received additional funding since their inception and thus have been declining simply due to the impacts of inflation. USGS surface water quality networks include the Hydrologic Benchmark Network (HBN), operating since 1964, and the National Stream Quality Accounting Network (NASQAN), operating since 1973. HBN monitors small watersheds in areas relatively free from human impacts, from water diversions, and from water impoundments, providing important baseline data for understanding water quality impairments and needed improvements. When it first began in 1964, HBN water quality sampling was quarterly to monthly depending on location, but since 1997 there has been no water quality sampling at the 52 watersheds (Mast and Turk, 1999). Beginning in 2003, limited sampling resumed at 15 of the remaining 36 watersheds.1 NASQAN measures water quality in the nation’s largest river systems, and it also includes many coastal drainages. At the program’s operational peak (in 1976), more than 500 locations were sampled either monthly or six times a year for major ions, nutrients, trace metals, indicator bacteria, and periphyton. Now, only 33 sites remain, with sampling at a frequency adequate for annual flux estimates and with new capabilities for sampling some pesticides. These networks now provide a fraction of the data they once produced (though some prior components may be handled by the NAWQA program—see below). Assessing water quality, both for trends over time and for causative factors, is growing in importance for water resource management. The NAWQA program provides data and information on the most important (defined by water use for municipal supply or irrigated agriculture) river basins and aquifer systems (study units). NAWQA comprehensively samples surface water and groundwater for physical and chemical variables, and it produces data on aquatic communities of 1 The program was reduced from 52 watersheds to 36 because USGS appropriations have been level or declining for several years, while costs increase about 4 percent every year (Robert Hirsch, Chief Hydrologist, USGS, personal communication, 2004).
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Confronting the Nation’s Water Problems: The Role of Research fish, insects, and algae. Originally NAWQA was designed for sampling 59 study units, but by 2001 only 51 were sampled, and now because of funding constraints only 42 study units continue to operate. Within NAWQA, many sampling activities have been curtailed. For example, between 1993 and 2001, more than 600 fixed-station surface water sites were sampled, but now only about 150 sites continue to operate. These sites provide the only continuous water quality trend sampling. Although thousands of bed sediment and tissue data were collected from streams in the first years of sampling, most of those sampling efforts cannot be repeated. Groundwater sampling between 1993 and 2001 included more than 6,500 wells. There are not adequate resources to sample those sites repeatedly for trends, and only 2,400 wells are being resampled in urban, agriculture, and large aquifer networks, reducing substantially the density of the sampling network. Although the numbers of wells may seem large, the trend network provides insight at an average of less than 60 wells per study unit (the median study unit area is 21,000 sq. mi.). The recent National Research Council (NRC) report (NRC, 2002a) states that NAWQA cannot decrease its number of study units further and still provide the national scope of data called for by Congress. Monitoring activities related to sediment are particularly crucial because it is the most widespread pollutant in U.S. rivers (EPA, 2002). The USGS is the principal source of fluvial-sediment data, providing daily suspended-sediment discharge data at about 105 sites (sediment stations) in 2002. These data serve traditional uses that include design and management of reservoirs and in-stream hydraulic structures and dredging. In the last two decades, information needs have expanded to include those related to contaminated sediment management, dam decommissioning and removal, environmental quality, stream restoration, geomorphic classification and assessments, physical–biotic interactions, the global carbon budget, and regulatory requirements of the Clean Water Act including the EPA’s Total Maximum Daily Load program. An increasing need for fluvial-sediment data has coincided with a two-thirds decline in the number of USGS sediment stations from the peak of 360 in 1982 (Gray, 2002) to about 105 sites now. Among the factors cited for the decline in the number of USGS daily sediment stations was the need for less expensive and more accurate fluvial-sediment data collected using safer, less manually intensive techniques. Any decrease in sediment monitoring should be of particular concern given that the physical, chemical, and biological sediment damages in North America alone were estimated at $16 billion in 1998 (Osterkamp et al., 1998). In its review of the NAWQA program, the NRC noted the serious need to improve sediment monitoring (NRC, 2002a). Box 5-1 discusses how the lack of reliable water quality monitoring data has hampered efforts to sensibly plan for development in New Jersey and comply with state laws. It exemplifies not only shortages in groundwater quality data, but also in flow data.
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Confronting the Nation’s Water Problems: The Role of Research BOX 5-1 Water Quality Monitoring in the Pinelands National Reserve In 2000, the New Jersey state legislature passed legislation authorizing the expenditure of $5 million for a study of the impacts of potential groundwater withdrawals on the ecology of the Pinelands National Reserve. The Pinelands National Reserve, an area of about 1 million acres, occupies the southern third of the state and is underlain by the Cohansey, an extensive groundwater aquifer. Development pressure in the lands surrounding the preserve, including the suburbs of Philadelphia, Pennsylvania, and Camden, New Jersey, the burgeoning Cape May peninsula, and the Atlantic City region, are intense. Building and economic activity in this area are increasingly limited by water availability; the aquifers currently being utilized are already overpumped and salinized. The Pinelands Reserve is protected by both state and federal legislation that specifies the protection of “the natural ecological character of the region” as the criterion for setting land-use policy. This large-scale (multistate) study was authorized in order to determine whether exports of water from the Pinelands watersheds to the surrounding developing areas would negatively affect the aquatic ecosystems of the Pinelands. During initial discussions about the scope of the research, the scientists involved (from the state Pinelands Commission, the New Jersey Division of the U.S. Geological Survey, and Rutgers University) decided that it was important to study watersheds across the range of aquifer and land-use conditions in the Pinelands. Thirty-five (35) subbasins were initially identified as potential intensive study areas. They represented the range of aquifer thicknesses (from less than 100 feet to over 500 feet), current rates of pumping (from 0 to 740 megagallons per year), land uses (from nearly complete forest cover to mixtures of developed and agricultural land with little forest cover), amounts and types of wetland, and stream lengths. Despite the large range of existing conditions in the subbasins, all but two of the subbasins were excluded from consideration as intensive study sites because they lacked the long-term monitoring data of both groundwater flow and water quality necessary to calibrate hydrologic, chemical, and ecosystem water balance models. Two other subbasins had partial records from continuous-flow monitors, and 15 subbasins had partial, discontinuous records from low-flow gages. Only nine subbasins had water quality monitoring data, and for only one of these was there a long-term continuous record. One of the subbasins with both long-term continuous flow and water quality records, McDonald’s Branch, is situated in the center of the region, is small and forested, has variable aquifer thickness, and lacks some of the wetland types of importance to the study. The other subbasin with
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Confronting the Nation’s Water Problems: The Role of Research long-term continuous water flow and water quality data, the East Branch Bass River, is much larger, with some urbanized land within the basin; however, it lacks some of the major aquatic communities that are the focus of the study. Thus, the lack of continuous water flow and water quality monitoring data from all but two of the subbasins prevented the research team from studying the range of conditions that would best answer the critical management questions posed by the legislation. Moreover, the team was constrained to use two subbasins that are not strictly comparable, in that each lacks an important component of the hydroecological system that is the target of this large-scale investigation. Water Use Estimating the demands for water and amounts withdrawn from various surface-water and groundwater sources is of critical importance to water resources management. Since 1950, the USGS has compiled and disseminated estimates of water use for the nation at five-year intervals. Most of the data are collected, however, not by the USGS but by the individual states to support their water-use permitting and registration programs. Although matching funds for the analysis and aggregation of water use data are often available through the USGS Cooperative Water Program, some states make little effort in this area. Thus, the quality of water use data varies considerably from state to state. Unfortunately, because of funding limitations, the USGS had to reduce the scope of reporting on a nationwide basis in 2000 for several categories of water use. Reductions in national scope included (1) eliminating estimates of commercial use and hydroelectric power (which is counter to recommendations in the Envisioning report [NRC, 2001]), (2) providing information for mining, livestock, and aquaculture only for large-use states, (3) eliminating estimates of consumptive use and public deliveries, and (4) compilation at the county, but not watershed, level. In a recently completed NRC review of the USGS National Water Use Information Program (NWUIP) (NRC, 2002b), basic questions about the nature of water use, the water use information needed in the United States, and the USGS role in generating and disseminating that information were considered. Major recommendations contained in the NRC report include the following: The NWUIP should be elevated to a water use science program (rather than a water use accounting program), emphasizing applied research and tech-
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Confronting the Nation’s Water Problems: The Role of Research niques development in the statistical estimation of water use and the determinants and impacts of water-using behavior. To better support water use science, the USGS should build on existing data collection efforts to systematically integrate datasets, including those maintained by other federal and state agencies, into datasets already maintained by the NWUIP. The USGS should systematically compare water use estimation methods to identify the techniques best suited to the requirements and limitations of the NWUIP. One goal of this comparison should be to determine the standard error for every water use estimate. The USGS should focus on the scientific integration of water use, water flow, and water quality to expand knowledge and generate policy-relevant information about human impacts on both water and ecological resources. The USGS should seek support from Congress for dedicated funding of a national component of the recommended water use science program to supplement the existing funding in the Cooperative Water Program. * * * The preceding section discussed some of the important data collection networks relevant to water resources research, but the discussion was not intended to be exhaustive. For example, both public health data collection (e.g., active disease surveillance) and monitoring of climate variables like precipitation were not discussed. This should not be interpreted as implying that they are less important types of data. Indeed, Box 5-2 discusses how federally funded monitoring for climate indices is routinely used to manage water resources in the Florida Everglades. CONCLUSIONS AND RECOMMENDATIONS Monitoring efforts are inseparable from the research efforts described in other chapters of this report. Furthermore, they are critical to addressing water resources problems related to floods and droughts, agricultural sustainability, global climate change, and other high priorities for water resources research (as expressed in Chapter 3). Indeed, the continuing need for high-quality, long-term in situ data was the only water resources-related issue expressed unanimously by 13 state government representatives who addressed the committee in January 2003 (see Appendix D).
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Confronting the Nation’s Water Problems: The Role of Research BOX 5-2 Real-Time Water Management in South Florida The South Florida Water Management District (District) is one of the largest nonfederal water management agencies in the country with farreaching authority over water use and environmental protection from Orlando to Key West. The area is blanketed by a mammoth series of federal water projects constructed by the U.S. Army Corps of Engineers primarily in the 1950s and 1960s. In recent years the District has developed unique approaches to operating federal facilities to achieve environmental benefits that were not valued when the project was first built, but without compromising the water supply and flood control requirements of the original project. Lake Okeechobee is at the heart of the water management system in South Florida, storing floodwater from the upstream watershed and supplying water for agriculture, urban populations, and the Everglades. It is also an indispensable natural resource that contains a contiguous 90,000-acre wetland system supporting thousands of wading birds and numerous endangered species, as well as supporting the sport fishing that is critical to the local economy. The need to manage this resource for competing and sometimes conflicting objectives has led the District to consider the results of the latest federally supported climate research in the process of making operational decisions. Both seasonal and multiseasonal climate outlooks produced monthly by the Climate Prediction Center of the National Weather Service have been incorporated into operations of the regional water management project. The District’s approach links local and global climate indices to on-the-ground hydrologic information to make weekly adjustments in water control for Lake Okeechobee. Many institutions around the country have active research programs, but few have been successful in implementing climate forecast information into day-to-day operations. Further, the District has taken the important step of revising the official water control manuals to formalize the routine employment of information provided by climate research programs associated with the National Oceanic and Atmospheric Administration and others. Without assistance from several federal research entities, the successful implementation of climate-based operations in south Florida, and the public’s acceptance of using innovative operational planning methods that employ forecasts, would not have been possible.
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Confronting the Nation’s Water Problems: The Role of Research The challenges to the monitoring of water resources are formidable and include a sizable increase in the number of features to be monitored, as the variety, scope, and complexity of problems expand, especially with respect to biological issues; a major expansion in the range of time/space scales that must be addressed by data collection and monitoring as new, major problems develop; and difficulties in making the increasingly large amounts of data available quickly and efficiently. The following conclusions and recommendations address the need to match these challenges, as well as emerging water resources problems, with new investments for basic data collection and monitoring. Key legacy monitoring systems in areas of streamflow, groundwater, sediment transport, water quality, and water use have been in substantial decline and in some cases have been nearly eliminated. These systems provide data necessary for both research (i.e., advancing fundamental knowledge) and practical applications (e.g., for designing the infrastructure required to cope with hydrologic extremes). Despite repeated calls for protecting and expanding monitoring systems relevant to water resources, these trends continue for a variety of reasons. The consequences of the present policy of neglect associated with water resources monitoring will not necessarily remain small. New hydrologic problems are emerging that are of continental or near continental proportions. The most obvious are the likely impact of global climate change on water resources; hypoxia in the Gulf of Mexico, related to nutrient loading from the Mississippi River; and the questionable sustainability of the water supply for western and southern regions given population increases and recent interest in restoring aquatic ecosystems (e.g., the Florida Everglades and the Mississippi River basin). The scale and the complexity of these problems are the main arguments for improvements to the in situ data collection networks for surface waters and groundwater and for water demand by sector. It is reasonable to expect that improving the availability of data, as well as improving the types and quality of data collected, should reduce the costs for many water resources projects. Notwithstanding the overall decline in legacy monitoring systems, there are some positive developments that bear on hydrologic monitoring. For example, the NEXRAD system provides unprecedented spatial resolution of rainfall distribution. Efforts have continued to support environmental earth-surface observations with new generations of satellites. Other NASA research missions (e.g., IceSat, TOPEX/Poseidon, GRACE) give positive early indications of their potential as monitoring tools for hydrologic systems. Although these new satellite-based measuring systems have important applications to hydrologic research, they are not yet ready to replace legacy monitoring systems. Moreover, for chemical, biological, and groundwater monitoring, in particular, new in situ and remote
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Confronting the Nation’s Water Problems: The Role of Research sensing technologies capable of replacing wells or field sample collections are still in development. Increases in strategic investments for monitoring are necessary to avoid or at least reduce costs attendant with future water resource or health crises. Investments are required but are not by themselves sufficient to ensure that the data necessary to attack 21st century problems will be available to researchers and policy makers alike. Federal agencies need to adopt a research perspective toward monitoring and data collection that better integrates monitoring with the research efforts described in other chapters of this report. There is also a strong need for cooperation among agencies concerned with collecting, storing, and managing hydrologic data, particularly from research watersheds and legacy monitoring systems. The NSF cyberinfrastructure initiative is an example of a visionary approach for creating comprehensive digital environments linking people and data. It is recommended that an interagency task force concerned with information technology and data management be established and that it develop a non-NSF federal cyberinfrastructure community. REFERENCES Alley, W. M., T. E. Reilly, and O. L. Franke. 1999. Sustainability of ground-water resources. U.S. Geological Survey Circular 1186. Alley, W. M., and C. J. Taylor. 2001. The value of long-term ground water level monitoring. Ground Water 39:801. American Society of Limnology and Oceanography (ASLO). 2003. Emerging Research Issues for Limnology: the Study of Inland Waters. Waco, TX: ASLO. Atkins, D. E., K. K. Droegemeir, S. I. Feldman, H. Garcia-Molina, M. L. Klein, D. G. Messerschmitt, P. Messina, J. P. Ostriker, and M. H. Wright. 2003. Revolutionizing Science and Engineering through Cyberinfrastructure. Washington, DC: National Science Foundation. Birkett, C. M. 1995. The contribution of TOPEX/POSEIDON to the global monitoring of climatically sensitive lakes. JGR–Oceans 100 (C12):25,179–25,204. Birkett, C. M. 1998. Contribution of the TOPEX NASA radar altimeter to the global monitoring of large rivers and lakes. Water Resources Research 34(5):1223–1239. Dagan, G., and E. Bresler. 1988. Variability of an irrigated crop and its causes: 3—numerical simulation and field results. Water Resources Research 24(3):395–401. Eastman, J. L., R. A. Pielke, and D. J. McDonald. 1998. Calibration of soil moisture for large-eddy simulations over the FIFE area. J. Atmospheric Sciences 55:1–10. Entekhabi, D., G. R. Asrar, A. K. Betts, K. J. Beven, R. L. Bras, C. J. Duffy, T. Dunne, R. D. Koster, D. P. Lettenmaier, D. B. McLaughlin, W. J. Shuttleworth, M. T. van Genuchten, M. Y. Wei, and E. F. Wood. 1999. An agenda for land surface hydrology research and a call for the second international hydrological decade. Bull. Amer. Meteor. Soc. 80:2043–2058. Environmental Protection Agency (EPA). 2002. National Water Quality Inventory—2000 report: EPA–841–R–02–001. Washington, DC: EPA. Ferraro, R., F. Weng, N. Grody, I. Guch, C. Dean, C. Kongoli, H. Meng, P. Pellegrino, and L. Zhao. 2002. NOAA satellite–derived hydrological products prove their worth. EOS 83(29):429–438. General Accounting Office (GAO). 2000. Key EPA and State Decisions Limited by Inconsistent and Incomplete Data. General Accounting Office RCED–00–54. 73 p. Washington, DC: GAO.
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Representative terms from entire chapter: