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2 NAWQA Design Evaluation INTRODUCTION As discussed in the previous chapter, the scope of a truly na- tional water quality assessment is enormous, both in scale and complexity. Hence, it is essential that the scope of NAWQA be defined judiciously in recognition of the overall budgetary con- straints, the organizational strength of the USGS, and the salient characteristics of the physical and cultural systems that define water quality. This chapter contains an evaluation of the design of the NAWQA program components, including integration of the surface water and ground water study units, how study units were selected, the general exclusion of lakes and estuaries from the study plan, the sampling design program, data collection methods, the choice of chemical and biological constituents, quality as- surance/quality control aspects, data management, the analytical framework of the program, and products of the NAWQA program. Integration of Ground Water and Surface Water Description The original concept specified 123 separate surface water and ground water study units: 69 surface water and 54 ground water. A major difficulty with the "separate" approach is that it had the potential for missing the important linkages between surface water and ground water systems--linkages that can have profound effects on the water quality of both systems. As the pilot programs pro- ceeded, it became apparent to the committee and to the USGS that the integrated approach was more beneficial. Some of the pilot programs provide good examples of the importance of incorpora- ting surface water and ground water interactions into water qual- ity studies. 26

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NAWQA Design Evaluation 27 For example, in the Delmarva Peninsula pilot project--a ground water investigation--pesticides have caused some contamination of surface water and shallow ground waters. The pilot project used transects of shallow wells installed adjacent to streams to track the infiltration of pesticides from agricultural lands down to the water table and from there into streams. The pilot project in the lower Kansas River basin--a surface water investigation--perhaps best exemplifies the importance of the integrated approach. Along the Kansas River, considerable interchange of water occurs between the river and its alluvial aquifer. During high flows, the river re- charges the aquifer, during low flows, base flow from the aquifer contributes an estimated 1 to 4 cubic feet per second of flow per river mile (Fader, 1974~. The exchange of water probably has a significant effect on ground water and surface water quality, although the effects were not known at the inception of the study. In the Blue River basin near the Kansas-Nebraska state line, streamflow depletion by wells is about two orders of magnitude greater than that predicted by an analog model in the early 1960s (Alley and Emery, MY. in the nor~nwes~ern per o~ `~; Buy unit (the upper Big Blue River and Little Blue River in Nebraska), the interaction between the streams and the aquifers is great. In dry periods, discharge from the High Plains aquifer sustains these streams. Irrigation return flow from the extensive croplands undoubtedly contributes to the relatively high specific conductance found downstream in the Kansas River; the sulfate ion is a major offender. Similarly, the use of nitrogen fertilizers may contribute to the upward trend in nitrite and nitrate levels in the Big Blue River; a major pathway could be base flow to the river. Ground water and surface water interaction is also important in some portions of the Central Oklahoma aquifer study unit; this was known prior to the inception of the pilot project. However, the spatial distribution of this interaction was different from that which was previously believed. Prior to the onset of the pilot project, the USGS team thought that most interaction occurred near the major streams, the Canadian and Cimarron Rivers. The pilot project team discovered that the major interaction occurred along two smaller streams, the Deep Fork and Little Rivers, which served as the major ground water sinks instead of the aforementioned larger streams. This surprising result could have important ramifi- cations for water quality, especially for the four streams involved. Certain other pilot projects might also benefit from an in- tegrated approach. The Yakima River basin pilot project--a sur- face water investigation--is one such example. Interchange between surface water and ground water is probably important in the

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28 NAWQA Pilot Program upper, forested reaches of the watershed. In the lower portion of the basin, over 400,000 acres are under irrigation. Subsurface irrigation return flow could affect stream water quality, as the potential exists for water quality degradation arising from irriga- tion (NRC, 1989~. Critique The original NAWQA plan to keep surface water and ground water study units separate had the potential for missing or mini- mizing important water quality linkages between these two systems. Therefore, in recognition of the important water quality implica- tions of surface water and ground water interactions and the committee's concern that the original NAWQA concept downplayed these implications, the USGS decided in March 1989 to redefine the study units. Instead of the original 123 separate study units, 60 integrated surface water/ground water study units now exist; selection of these new units will be discussed in another section. The study units are shown in Figure 2.1 and listed in Table 2.1. Summary The emphasis on integrated study units will result in an im- proved program since it will now examine the water quality of an integrates! hydrologic system. Flow paths between aquifers and streams will be delineated so that the investigators will be able to quantify the effects of one component (i.e., surface water or ground water) of the system on the water quality of the other component. The integrated approach will also allow the investi- gators to ascertain the physics of the system to a greater extent than before, thus enabling them to understand the cause and effect relationships, which could be extended to other parts of the coun- try. One of the important aspects of the NAWQA program is an understanding of water quality cause and effect relationships, and the committee believes that the integrated approach will enhance such understanding. The USGS plans to use teams of surface water and ground water specialists to review study unit findings in an effort to develop a basic understanding of the interrelationships among surface waters, ground waters, and the water quality constituents carried by those waters. To the extent that these reviews are successful, they should enable better plan- ning of new projects as they come on-line.

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NAWQA Design Evaluation :__ · . . r 29 FIGURE 2.1 Proposed NAWQA study units in the United States. SOURCE: Leahy et al, 1990.

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30 NAPTHA Pilot Program TABLE 2.1 Proposed Study Units for a Full-Scale National Water Quality Annulment Program USGS Northeastern Region 1. New Hampshire-Southern Maine Basins 2. Southeastern New England 3. Connecticut Valley Drainage 4. Hudson River Basin 6. Long Island 6. Delaware River Basin 7. Lower Su~quehanna River Basin 8. Delman~a Peninsula 9. Potomac River Basin 10. Allegheny and Monongahela River Basins 11. Kanawha River Basin 12. Lake Ene-Lake Saint Claire Drainage 13. Great and Little Miami River Basins 14. White River Basin 15. Upper Illinois River Basin 16. Lower Illinois River Basin 17. Westem Lake Michigan Drainage 18. Minneapolis-St. Paul Basin 19. Red River of the North USGS Southeastern Region 20. Albemarle-Pamlico Drainage 21. Upper Tennessee River Basin 22. Santee Basin and Coastal Drainage 23. Apalachicola-Chattahoochee Basin 24. Georgia-Florida Coastal Plain 25. Southern Florida 26. Kentucky River Basin 27. Mobile River and Tributaries 28. Mi~i~ippi Delta 29. Chicot-Evangeline 30. Lower Tennessee River Basin USGS Central Region 31. Eastern Iowa Basins 32. Ozark Plateau 33. Central Oklahoma 84. Trinity River Basin 35. Balcones Fault Zone 36. Central Nebraska 37. Kansas River Basin 38. Upper Arkansas River Basin 39. Central High Plains 40. Southern High Plains 41. South Platte River Basin 42. North Platte River Basin 43. Cheyenne and Belle Fourche Basins 44. Yellowstone Basin 45. Upper Colorado Basin 46. Rio Grande Valley 47. Northern Rockies Intermontane Basins 48. Great Salt Lake Basin USGS Western Region 49. Upper Snake River Basin 50. Southern Arizona 51. Mid-Columbia Basin 52. Yakima River Basin 5S. Puget Sound Drainages 54. Willamette Basin 55. Sacramento Basin 56. Western Great Basin 57. San Josquin-Tulare 58. Santa Ana Basin 59. Oahu 60. Cook Inlet Basin

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NAWQA Design Evaluation 31 Lakes and Estuaries Description In the NAWQA program the term "surface water" is virtually synonymous with "stream." Estuaries will not be considered in the program. Lakes (including impoundments) will only be considered if they significantly affect downstream water quality. However, the extent of this consideration is not clear, nor is the manner in which the significance of individual lakes will be evaluated. The exclusion of lakes has been justified by the USGS on the basis of cost. Critique Estuaries and lakes (including impoundments) are critical components of the nations water resources. Much of the surface water supply of the nation is drawn from lakes (either natural or engineered). Lakes and estuaries support rich and diverse ecosys- tems, which provide the basis of an extensive seafood industry and abundant recreational opportunities. Lakes also interact with other freshwater components of the hydrologic cycle, in that they act as both sources and sinks of various water quality constituents. Thus they can significantly affect downstream surface water or down- gradient ground water quality. It is clearly in the nation's interest to monitor, assess, and understand the water quality of both lakes and estuaries. With respect to the major estuaries and lakes in the nation, extensive assessment programs already exist. Notable examples include the Chesapeake Bay, San Francisco Bay, and the Great Lakes. In general, the level of activity in these large systems is much greater than could be supported under the NAWQA program. At best, NAWQA can provide additional information regarding loadings of various water quality constituents. However, NAWQA can and should benefit from the modeling techniques that have been developed during the intensive investigations of these major lake and estuary systems. In the aggregate, the smaller lakes and estuaries in the nation constitute a very important resource. While the committee believes that this resource deserves attention, it supports the decision of the USGS at this time to exclude estuaries from NAWQA and to consider lakes only insofar as they affect downstream surface water quality and downgradient ground water quality. This support is based on our recognition that the USGS, while

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32 NAWQA Pilot Program traditionally strong in mathematical modeling of estuaries and lakes, has relatively little experience or capability in biological ant} chemical modeling. The committee, however, believes strongly that the USGS must include in NAWQA consideration of those lakes that significantly affect downstream or downgraclient water quality. This considera- tion should involve more than just upstream ant! downstream monitoring of water quality, and should include some degree of mathematical modeling. If developed in the early stages of a study unit, a preliminary model can be used to establish the potential significance of existing lakes, and to guide the monitoring pro- gram. Once collected, monitoring data can be user! to evaluate the moclel, and if warranted, to guide its improvement. This in turn may lead to adciitional monitoring requirements. This iterative use of models is an essential element of a process-oriented assessment, and is discussed further in the Analytical Framework section later in this report. Summary The committee believes that an assessment of the long-term trends in the water quality of lakes (including impoundments) and estuaries should be part of any long-term national water quality assessment. At some point, the water quality of lakes should receive the same level of attention in the NAWQA program as that of streams and ground water. However, given the present lack of personnel in the USGS with expertise in the biological and chemi- cal modeling of lakes and estuaries, we believe that the NAWQA program should not be expanded at this juncture to include es- tuaries. However, we recommend that initially lakes should be considered but only as they affect downstream surface water quality or downgradient ground water quality. The committee further recommends that the first set of inves- tigations in the NAWQA program include one or more study units in which lakes are likely to be significant contributors to down- stream and/or downgradient water quality. This will give the USGS an opportunity to enhance its capabilities with respect to lakes. Additionally, we recommend that mathematical models be developed at the initial stages of each study unit investigation involving lakes.

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NAWQA Design Evaluation Introduction Selection of Study Units The selection of study units is described in Hirsch et al., 198S, which is the source for much of the discussion in this section. Some changes in the study unit selection process, as described in Hirsch et al., 198S, were dictated by the decision to designate combined surface water-ground water study units; these changes are included in the discussion herein. Since the selection of study units is based largely upon the USGS's hydrologic unit classifica- tion system, a brief description of that system, taken from Seaber and others (1986), is warranted. Description The USGS divides the United States into 21 major geographic regions and 222 hydrologic subregions. The regions contain either the drainage area of a major river, such as the Missouri region, or the combined drainage area of a series of rivers, such as the Texas- Gulf region, which includes a number of rivers draining into the Gulf of Mexico. Eighteen regions comprise the conterminous United States, with individual regions specified for Alaska, the Hawaiian Islands, and Puerto Rico and other Caribbean areas. A hydrologic subregion includes the area drained by a river system, a reach of a river and its tributaries in that reach, a closed basils), or a group of streams forming a coastal drainage area. These subregions are further subdivided into 352 accounting units that nest within, or are equivalent to, the subregions. The accounting units are used by the USGS in designing and managing the National Water Data Network. A set of 200 surface water candidate study units (CSUs) were identified, based primarily on the hydrologic subregions described in Seaber and others (1986~. When a given subregion was too large, it was subdivided to form a number of CSUs. In other cases, subregions were combined into a single CSU or a particular ac- counting unit from one subregion was added to another. In the selection of the surface water CSUs, attempts were macle to select ones having similar areas. Modifications were sometimes made to ensure that all sources to a major lake or estuary were contained within the same CSU. An attempt was also made to select CSUs that had relatively homogeneous land use and environmental characteristics. A set of 116 ground water CSUs were also iden- tified. The boundaries of these CSUs were less well defined than ~ _ _ 33

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34 NAWQA Pilot Program those of the surface water CSUs; in some cases, ground water CSU boundaries coincided with those of surface water CSUs. Each set of CSUs was screened using a modified linear pro- gramming model (Fox and Scudder, 1986~. The objective function of the linear program minimized the number of study units se- lected, given certain constraints: (1) the study units account for about 60 percent of the nation's water use, as measured by popula- tion served by public water supplies and by total withdrawals excluding thermal and hydropower uses; and (2) each state contains at least one study unit having at least 30 percent of its area within that state. This exercise yielded two maps: one of surface water study units and one of ground water study units. Next, a few study units that were downstream of major river basins (e.g., the Colorado and Ohio rivers) were deleted; the rationale for these deletions was that these basins integrate water quality conditions for many upstream basins (Hirsch et al., 1988~. The two sets of study units were then merged and reviewed by all USGS district and regional offices to provide study unit boundaries that ac- counted for both surface water and ground water boundaries. Some study unit boundaries may be refined once the full-scale program gets under way. Finally, study units were specified for Hawaii and Alaska. The 60 study units encompass about 40 per- cent of the land area of the conterminous United States and incor- porate about 60 to 70 percent of the nation's water use (fresh surface water withdrawals excluding thermal and hydropower uses). It should be noted that in selecting the study units, emphasis was placed on "key river basins" and ground water units that corresponded somewhat to the USGS Regional Aquifer Systems Analysis (RASA) program. Essentially, the purpose of the RASA program is to emphasize the physical hydrogeology of certain regional aquifers. By attempting to coordinate NAWQA study units with RASA efforts, the USGS will take advantage of infor- mation already being generated. The RASA program emphasizes the physics of the ground water systems, something that must be understood to undertake a water quality assessment that seeks to identify cause and effect relationships. The coordination of RASA and NAWQA, where possible, will result in an improved NAWQA product. Critique The geographic coverage of the study units is good, considering that only 40 percent of the continental United States is included.

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NAWQA Design Evaluation 35 The variation in size is substantial: the smallest study unit, Long island (number 5 in Figure 2.1 and Table 2.1), is about 1,300 square miles, and the largest is the Ozark Plateau (number 32), which is over 60,000 square miles. The pilot project study units are rela- tively small--3,000 to 15,000 square miles. Given the large size of approximately eight study units, the combined ground water-sur- face water nature of these study units, and the USGS's lack of experience in a large study unit, the committee is concerned that NAWQA objectives may not be met in some of the larger units. Summary Study unit selection is generally good; the coverage is broad and represents a variety of hydrologic regions. Coordination of study units with RASA study areas is an approach that should result in some degree of synergism and aid in delineating cause and effect relationships. Some of the study units are quite large, much larger than any of the seven pilot project study units. To see how well the NAWQA program can accommodate a large study unit, the committee recommends that early in the full-scale NAWQA program, the U.S. Geological Survey select two large study units for investigation. SAMPLING DESIGN Sampling Approach Introduction The NAWQA pilot program originally consisted of separate surface- and ground-water study units with separate sampling designs. The committee's evaluation therefore considers the sur- face- and ground-water sampling designs separately. The full- scale NAWQA will be based on combined surface- and ground- water study units; however, a combined sampling design has not yet been developed. Hence, the committee also points out some issues that need to be considered in designing a sampling program for the combined surface- and ground-water study units. Ground Water Description The major objectives of the ground water investiga- tions (Hirsch et al., 1988) are to (1) describe ground water quality

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36 NAUSEA Pilot Program conditions for major hydrogeologic settings; (2) describe the geo- graphic distributions within the study units of selected water quality constituents and problem areas; (3) define long-term trends in ground water quality; and (4) identify, describe, and explain, if possible, the major factors that affect observed current conditions and trends in ground water quality. To attain these objectives, NAWQA projects will conduct three different types of ground water sampling activities: (1) regional, (2) targeted, and (3) long term. Regional sampling will be conducted throughout each major hydrogeologic setting within a study unit. All of the national target variables for chemistry and physics will be measured in an effort to provide descriptive statistics and to form an initial basis for describing the geographic distribution of water quality vari- ables within the study unit. Sampling will be done in three dimen- sions and will be designed to be unbiased with respect to particular "problem areas." Targeted sampling will occur in selected locations for specific groups of water quality constituents; it will focus on "problem areas" but will not be a "plume chasing" exercise. As an example, in the Central Oklahoma aquifer pilot project, targeted sampling variables are (1) naturally occurring trace substances (NOTS) such as arsenic, selenium, chromium, uranium and gross-alpha radio- activity and (2) organics (especially pesticides) beneath central Oklahoma City. Problem areas for targeted sampling will be identified from the regional sampling results, knowledge of the hydrogeologic and land-use factors that contribute to water quality, and consultation with local agencies and individuals involved with ground water quality. Three targeted sampling approaches will be used: (1) search-oriented sampling, (2) statistical hypothesis testing, and (3) local-scale transects (Hirsch et al., 1988~. Local-scale transects will involve high-density sampling of one or more wells per square mile to characterize representative set- tings that commonly occur throughout large parts of the study unit. These local-scale studies should be useful for examining the inter- relationship between surface water and ground water quality. Transects provide very good information about a study unit's physical hydrogeology. The Delmarva Peninsula pilot project has used transects of shallow wells installed adjacent to streams to follow the infiltration of pesticides from agricultural lands down to the shallow aquifer and from there into streams. Local-scale transects have also been used in the Carson basin pilot project. Search-oriented sampling will involve sampling for constituents within particular settings in which they are most expected. The

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62 NAWQA Pilot Program completeness and conformance to information management guide- lines. Laboratory QA samples were checked against NAWQA minimum standards and for proper review and (if needed) action. Critique The USGS appears to be committed to ~ sound practice of quality assurance and quality control. The QA program assures that technically sound procedures will be used in the NAWQA program. The reviews demonstrated that the proposed QA/QC program is working in the study units. The review process provided a com- plete examination of the QA/QC program in the study unit. It identified deficiencies and actions to correct them. In addition, the reviews identified areas where additional national guidance should be considered to aid the study units. The following were items mentioned in more than one study unit review: 1. concerns with aspects of low-level trace organic analyses; 2. the need for national archival guidelines; and 3. more guidance on how to evaluate the QA laboratory samples. The site review program is an effective process for assuring the integrity of the NAWQA quality assurance program. Summary The proposed QA plan is a sound approach for managing the NAWQA data bases to ensure utility and longevity beyond the first rotation of sites. In the full NAWQA program, periodic data base reviews will need to be continued to ensure completeness and accuracy of data. The results of all the pilot project audits should be reviewed for recurring areas of concern--particularly with monitoring for low-level organic compounds. The committee be- lieves that the QA program is a strong component of the NAWQA program. For the program's stated purposes it is desirable to have one agency, preferably a nonregulatory agency, responsible for a program of this scale. Consistency of sampling protocols and data collection will aid in analysis and be essential for timely and meaningful interpretation and synthesis. It is important that the headquarters person in charge of QA be in regular communication with the four regional NAWQA QA personnel to coordinate their activities closely, thereby ensuring that comparable standards and practices are being employed across the full NAWQA network of sites.

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NAWQA Design Evaluation 63 There is a lack of consistency in terms of water quality data collected by federal agencies. In the EPA 305(b) program, each state defines its water quality issues (USEPA, 1989~. The com- mittee would like to see more coordination of the NAWQA program with other agencies, especially in such areas as uniformity of water quality parameters monitored and more consistent sampling and analytical techniques. The NAWQA program has the advantage over EPA's 305(b) program owing to its coordinated effort among the four USGS regions in terms of data collection protocols and methods. While local issues are important, the committee believes that the national synthesis planned in NAWQA will be a contribu- tion. In time, after a full NAWQA has been operational, it would be desirable for the USGS to determine how much overlap exists between the two programs, NAWQA and 305(b) to avoid costly duplication of effort. At the very least, both agencies should have access to the data from both programs. Data Management Description For data management (i.e., data documentation, collection, archiving, and retrieval), the pilot studies have used the USGS National Water Data Storage Retrieval System (WATSTORE) and the National Water Information System (NWIS) data bases, which are periodically transferred to EPA's STORET system. For the full NAWQA program, a new system, NWIS-2, is being designed and is targeted for operation in FY 1992. The development of this system is currently under way as part of the upgrading of computer resources for the Water Resources Division of the USGS. Critique WATSTORE is on a 15-year-old Amdah} Computer, which uses outdated computer technology from the 1960s and 70s (W. Wilber, personal communication 1989~. People unfamiliar with WATSTORE have great difficulty using the system. As part of the computer upgrade mentioned above, the USGS is developing speci- fications for a new water quality information system. Eventually, NWIS-2 will replace WATSTORE (W. Wilber, personal communica- tion 1989~. Currently, state data bases are on Prime computers that are uploaded to the national WATSTORE system and are periodi- cally transferred to EPA's STORET system. It is not clear whether

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64 NAWQA Pilot Program the new system will handle the Geographical Information System (GIS) data any differently from what was done in the pilot studies. The committee endorses the revamping of WATSTORE and en- courages the USGS to work quickly to develop and implement NWIS-2. The NAWQA criterion for acceptable storage and documenta- tion is to ensure that the data records and documentation will be useful to a succeeding project team 6 or more years after comple- tion of the initial investigative phase (i.e., beyond the first cycle of activity). In addition to the sanitary water quality data, the ecological survey is documenting the current status of the biologi- cal community (fish and invertebrate distribution data and tissue sampling for bioaccumulation) at each NAWQA site to provide a basis of the spatial variation and assess long-term changes in the biological community. The data management plan for the Ecologi- cal Survey is currently being revised. Sharing information and data files with the USGS within the scientific community is not easy because very few of the USGS personnel are connected to the Internet, a collection of local net- works (campus, governmental, and industrial) linked together by regional networks and attached to a national backbone (NSF Net). The purpose of the Internet is to provide high-speed communica- tion among members of the scientific community and to provide access to remote computing resources. Linking the USGS scientists to the scientific community via Internet would facilitate greater collaboration and coordination. Summary The committee believes it would be much easier to communicate with the USGS if their personnel and their computers had access to the Internet system. This would facilitate better coordination with universities and other research facilities and agencies. The committee endorses the revamping of WATSTORE and encourages the USGS to work quickly to develop and implement their new national water information system. ANALYTICAL FRAMEWORK Description For reasons discussed in Chapter 1, the committee firmly believes that a national assessment of our nation's waters must take a strong process-oriented approach. Such an approach improves

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NAWQA Design Evaluation 65 basic understanding of the physical, chemical, and biological processes that contribute to water quality and is essential to intel- ligent water-resource management. The committee further believes that the basic design of NAWQA is strongly process-oriented, and that the USGS is well suited to execute such a design. Much of the NAWQA design reflects an emphasis on hydrologi- cal processes. Study units are based on hydrological boundaries. Monitoring locations will be determined based on understanding of the relevant flow system. Synoptic surface water surveys provide opportunities to sample distinct hydrological events. Reach studies ~ ~ . . ~ ~ ~ . ~ . ~ ~ and local-scale transects enable aetallea analysis OI lmpOrlalll subsystems. The integration of surface water and ground water studies provides sorely needed opportunities to understand the important interactions between surface and ground waters. The USGS is ideally suited to conduct a process-oriented assess- ment of our nation's waters. The overall mission of the USGS is to provide information that will assist resource managers and policy- makers at the federal, state, and local levels in making sound decisions. This information is generated through assessments of the quantity and quality of the nation's natural resources, in- cluding minerals, energy resources, and water. In the case of water resources, the USGS has collected and interpreted data on water quantity and quality for more than 100 years. While many of these investigations have been relatively small in scale, a signifi- cant number have been comparable to a NAWQA study unit. A notable example is the ongoing study of selenium in the San Joaquin Valley in California (Gilliom, et al., 1989.) The committee reviewed the activities of the USGS in this study and was favor- ably impressed with the scientific understanding that has resulted. Furthermore, it is clear to the committee that without such under- standing, management strategies in the region would be poorly grounded. The strength of the USGS in conducting a process-oriented assessment of our nation's waters lies in the fact that it has well- trained, personnel representing a variety of disciplines dispersed throughout the nation. This means that a particular study-unit investigation will not be starting from scratch, since it will have access to personnel who understand the local and regional hydrol- ogy. Given the enormous variation of the hydrologic processes through the nation, such expertise is critical. Therefore, the committee believes that the NAWQA design has a strong process orientation, and that the USGS is well suited to execute the design. However, in the course of evaluating the NAWQA program, the committee also concluded that the ability of NAWQA to elucidate hydrologic processes should be strengthened

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66 NAWQA Pilot Program by a greater reliance on mathematical modeling. This issue is discussed in the subsequent sections. Critique An important feature that appears to be lacking from the overall NAWQA program, particularly the regional pilot studies, is the quantitative and analytical framework that identifies the principal cause and effect relationships. While this issue has been qualitatively addressed in NAWQA documents and in comments by USGS personnel, its quantitative definition, which is essential for decisionmaking, appears to be inadequate at this stage. The link between sources, both point and distributed, and the water quality response of a particular system, can be provided by a mathematical model that defines the spatial and temporal distribution of the concentration of relevant water quality constituents. The formula- tion of such a model should be an integral part of the individual studies. Although it has been stated or suggested that some kind of modeling would follow the data collection, there remains a reason- able question that this task may not be effectively realized. More importantly, the structuring of a quantitative model should be incorporated in the early phase of each project, to whatever degree is possible given the nature of the problem and available data. The use of models can serve many purposes in NAWQA. First, a model provides a tool for organizing what is known about a given system, at the scale of interest. Consequently, a model also serves to reveal gaps in knowledge. A model can be used to pre- dict what should be the critical factors affecting water quality (e.g., point versus nonpoint sources). This information can be used in designing the sampling strategy. Once data have been collected, they in turn can be used to refine the model. A model provides a way to account explicitly for meteorologic and hydrologic varia- tions. This makes it much easier to resolve water quality impacts caused by other factors, such as human activities. It also makes it possible to extrapolate for conditions other than those observed during the sampling period. A model can be used to simulate water quality for different scenarios of human activity. Such a capability is essential for evaluating hypothetical management options and is also useful in evaluating the impact of past manage- ment practices. Thus, water quality modeling can be used in all phases of water quality assessment, including design of the monitoring program, analysis of data, and evaluation of past and potential management

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NAWQA Design Evaluation options. Of particular importance is the interactive nature of modeling and data collection. These activities are mutually sup- portive, and each should evolve throughout the assessment process. This will lead to a better assessment, as well as to an improved understanding of the relevant physical, chemical, and biological processes. 67 Just as we recognize the necessity for using models in NAWQA, we also realize that the state-of-the-art in water quality modeling may have to be improved if models are to be used effectively in support of NAWQA. While a number of excellent surface water quality models are widely used for management purposes, most notably those supported by EPA, the applicability of these models to large spatial scale water quality assessment is unclear. Existing surface water models were designed to be used at relatively small scales and are most commonly applied to evaluate compliance with standards under hypothetical flow conditions (such as the 7-day, 10-year low flow). In comparison, NAWQA study-unit investiga- tions will be conducted! at enormous scales and will involve a very large suite of water quality constituents over a wide range of flow conditions. With respect to ground water, the USGS has played a leading role in developing models of both flow and quality. Of particular importance is the large-scale flow modeling that was undertaken by the USGS in the RASA program. These models should provide a framework for ground water modeling in many of the NAWQA study units (and in fact, have been used this way to some extent in the pilot studies). What remains, of course, is the incorporation of water quality into these models. A more difficult challenge is the integration of surface water and ground water _.__ ^— and_ arm_. ~—In,. . _^ ~ modeling. Given the lack of appropriate existing models in some cases, the USGSts inexperience in most cases, and the considerable difficulty of the task, some models will prove inadequate or infeasible. Therefore, a midcourse model evaluation should be built into the assessment cycle so that corrections can be made in sufficient time. Summary Water quality modeling should be an essential component of NAWQA. In the short term, the USGS should make use of existing models. Because the USGS has relatively little experience with existing surface water quality models, it will need to begin ~ :~ A ~ ~ : :- ~ ~ There is also a critical need to determine the data required by these models, since the current NAWQA design may not include collection of immenlatelv to nrov~de Or nDtaln the necessary tralDlnE.

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68 NAWQA Pilot Program necessary data. (For example, there is no plan to collect meteoro- logical data, which will be essential for watershed models of water quality.) During the first round of intensive monitoring, the leading water quality models should be applied over a wide range of situations. This would not only enhance the assessment effort, but would also provide valuable information on the capabilities of the models. A midcourse mode' evaluation should be built into the assessment cycle so that corrections can be made in sufficient time. Over the long term, the USGS should be developing a coherent strategy for water quality modeling in the context of a large spatial scale assessment, addressing such issues as scale, model complexity, and surface and ground water interactions. To the fullest extent possible, this should be done in cooperation with other federal agencies, particularly the Environmental Protection Agency. PRODUCTS Description The goals of NAWQA are to "describe the status and trends in the quality of the nation's surface and ground water resources and to provide a sound, scientific understanding of the primary natural and human factors affecting the quality of these resources" (Ap- pendix B. #36) in order to "provide an improved scientific basis for evaluating the effectiveness of water quality management programs and for predicting the likely effects of contemplated changes in land and water management practices" (Appendix B. #38~. Essential to achieving this goal of improving the evaluation and prediction of the consequences of management practices is the dissemination of the results of NAWQA to the appropriate audi- ences. The USGS has proposed three broad classes of report topics to be prepared under NAWQA (Appendix B. #38~: 1. statistical descriptions of water quality conditions and changes over time, 2. information on the geographic distribution of contaminants across the United States, and 3. information on key factors that affect water quality. It is the committee's understanding that this information will be provided in USGS water-supply papers, open-file reports, water resources investigations reports, yearbook articles, and other publi- cations, as well as in scholarly journal articles. For example, each

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NAWQA Design Evaluation 69 pilot project has been assigned a Water-Supply Paper number. The "A" chapter of each will be a project summary, the "Be chapter will be a retrospective report (see below), and later chapters will be specific to each study unit (Appendix B. #37~. Presentation methods in these reports will include tables, graphs, maps, and supporting text. Raw data will be available via a single, consistent computer data base. Similar products are to be prepared for both the study-unit investigations and the issue-based and national synthesis team studies. Unfortunately, because of the timing of the committee's review, no NAWQA reports presenting results at either the study-unit or synthesis level were available for review, with the exception of retrospective reports for 5 of the pilot projects (Appendix B. #62, 70, 79, 83, 89~. Therefore, our evaluation of NAWQA products is necessarily broad and general for the most part. The retrospective reports available for review focus on compiling available existing data from federal, state, and local agencies, evaluating the suit- ability of these data for NAWQA study unit activities, and pre- senting a preliminary spatial analysis of water quality conditions in the study unit via mapping, summary statistics, and descriptive text. They also contain background material of the study unit, its natural and cultural features, and its hydrologic systems. Critique The retrospective reports available for review have been pre- pared and designed well, and should serve the purpose for which they were intended. During their visits to the pilot projects, committee members were frequently told that the compilation of all available data into one documented source and data base was by itself a significant contribution to local decisionmaking. The reports do exhibit some unevenness in the quality of their analyses, with some study-unit teams apparently being more capable and creative than others in extracting and presenting useful informa- tion from the available data. After examining the more general aspects of the planned products of NAWQA, the committee first noted that the maps and reports at the USGS are in general highly respected among the potential users of NAWQA. Potential users interviewed by the committee were practically unanimous in that opinion. In fact, some local and state users made the point that data and informa- tion provided by the USGS will be far more helpful to them in their water quality management responsibilities than data and information acquired by the users themselves because local and

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70 NAWQA Pilot Program state governmental authorities have such high regard for the integrity of the USGS. One concern brought to the attention of the committee during its evaluation is the timeliness of USGS reporting. A number of potential users expressed frustration at the time required for publication of USGS reports, especially those containing data. The committee commends the USGS for its decision to publish the Water-Supply Papers for the pilot projects initially as open-file reports in order to accelerate the availability of this information. However, the committee would like to encourage the USGS to be vigilant and creative in seeking out ways to minimize the time required to publish NAWQA findings. In considering the three broad classes of report topics en- visioned by the USGS for NAWQA, the committee noted that the first two classes will be of greatest interest in support of policy formulation and resource allocation at fairly high levels of deci- sionmaking, while the third class will be of greatest interest to water quality management decisionmaking at the implementation level. It was also noted that the first two classes of reports will in many ways be the easiest to produce. The committee urges the USGS to strike an appropriate balance and assure that adequate resources are directed toward reports describing the results of cause and effect analyses, even if those are more difficult to produce. Many of the potential users of NAWQA with whom the committee spoke, especially on the local and state levels, em- phasized the value they would place on reports bettering their understanding of processes. The committee is most concerned, however, with the relatively narrow scope of the retrospective studies. While the study-unit teams appear to have been thorough in identifying and acquiring available data, the extent of their investigations was quite limited. In particular, the investigations focused almost exclusively on ambient water quality data in streams and aquifers. Data on sources of contamination were not collected and analyzed, in spite of the availability of extensive data bases (e.g., EPA's Permit Compliance System and Industrial Facility Reports). In addition. the retrospective reports make no attempt to identify and assess available studies of water quality processes in the study units or available water quality models that have been developed for all portions of the study units. If the goal of NAWQA is indeed to improve our understanding of water quality processes on the study- unit, regional, and national scales, it is imperative that information on sources and previous investigations of processes be included within the concept of a retrospective report.

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NAWQA Design Evaluation Summary The committee recommends that the concept of a retrospective report be expanded to include data on known sources of water quality constituents, existing studies of water quality processes within the study unit, and previously developed conceptual and mathomat;ral mn~l~lc of the nhvsical. chemical. and biological 71 .——~ . ., _ ~ ~ .~ ~ , ~ , _ processes influencing water quality in the study unit. The committee encourages the USGS to be vigilant and creative in seeking ways to minimize the time required to publish the findings from the National Water Quality Assessment program. In addition, the committee urges the USGS to ensure that adequate resources~are directed toward reports describing the results of cause and effect analyses, even if those are more difficult to produce. Committee-Initiated Case Study Description In order to obtain a sharper focus on how a cause and effect analysis would be conducted under the NAWQA program, the committee recommended that the USGS conduct a special study of the effect of changes in wastewater treatment on trends in the downstream water quality of the Illinois River. Wastewater treat- ment was selected as the problem area owing to the large federal investment in these facilities The Illinois River Basin was selected as the study area because ~t Is relatively simple from a hydrologic point of view and an extensive long-term data base already exists. As a result of this request, NAWQA personnel conducted a detailed inventory of past and present wastewater treatment data in this area. Their study focused on the ava~lan~ty and su~t- ability of municipal wastewater treatment information. Their results, indicating several areas where significant improvements are needed, are being featured in a series of three articles in Water Environment and Technology, the journal of the water Pollution Control Federation (Appendix B. #46) and in a USGS Open File Report (Appendix B. #57~. . · . . · . ~ . . · . Critique Although the NAWQA personnel did a very thorough evalua- tion of quality control problems with the existing data, they have not yet completed the originally requested analysis of cause and

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72 NAWQA Pilot Program effect relationships for this test study area. Thus the committee cannot evaluate how cause-and effect analysis is to be ac- complished under the NAWQA program. While it is understand- able that the USGS is more comfortable monitoring since it is their traclitional forte, NAWQA needs to be a first-class assessment activity if it is to serve its intended! purpose. Summary The USGS should immediately intensify its cause and effect assessment activities and provide complete case studies and a coherent national methodology for doing cause and effect assess- ments. This initial effort should utilize all available data and not be restricted to data generated by the NAWQA monitoring pro- gram. The results of this effort should be reviewed by an external science advisory committee.