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6 Conclusions and Recommendations Groundwater is a vital national resource. Providing accurate and timely information to manage and maintain the quantity and quality of the nation's groundwater requires resource assessments and scientific investigations across a variety of spatial and temporal scales. The U.S. Geological Survey (USGS) is uniquely qualified to conduct and synthe- size broad-based investigations. As outlined in an earlier review of the National Water-Quality Assessment (NAWQA) Program (NBC, 1994), the committee believes that regional and national synthesis of inforrna- tion must be a key part of the USGS groundwater program. The purpose of the regional- and national-scale groundwater investi- gations envisioned in this report is to provide a framework for decision- makers and a starting point for future site-specific studies by analyzing hydrogeologic processes and conditions relevant to wide areas of the United States. A general characteristic of regional investigations is that they cover hundreds to thousands of square miles and usually extend across state boundaries. However, beyond this commonality, the defini- tion of a "region" varies with the specific problem being addressed. Some regional investigations, such as studies of the High Plains aquifer, may target hydrogeologically distinct, geographically contiguous areas. Other regional studies, such as investigations of salt-water intrusion, may focus on discontinuous but widespread areas, encompassing related nonadjacent aquifer systems sharing common processes. The committee has reviewed, and is in general agreement with, the Strategic Directions for the U.S. Geological Survey Ground-Water Re- sources Program (USGS, 1998~. This document proposes scientific 105
Conclusions and Recommendations 109 assessment of critical groundwater issues combined with a program of regional and national overviews, access to groundwater data, and research and methods development as key components for heightened work on regional groundwater assessments. The following conclusions and recommendations are intended to enhance this plan and address each of the proposed priorities. SCIENTIFIC ASSESSMENT OF CRITICAL GROUNDWATER ISSUES Conclusion: Policy-relevant regional and national assessments of the sustainability of groundwater supplies under current and projected pat- terns of groundwater use are essential for Tong-term resource- management decisions. Assessments of sustainability represent the synthesis of resource inventory and characterization, process studies, problem identification, and decision support. The recently published circular Sustainability of Ground Water Resources (Alley et al., 1999) shows the wide range of these interlocking issues. The broad topic of sustainability includes the interaction of management decisions (e.g., pumping rates, conjunctive use of groundwater and surface water), re- source dynamics (e.g., climatic change, recharge rates), environmental impacts (e.g., streamflow depletion, water quality degradation), and emerging technologies (e.g., aquifer storage and recovery projects). Conclusion: Within the overarching theme of sustainability, the com- mittee recommends that the following groundwater issues be given the
110 Investigating Groundwater Systems highest priority for investigation by the USGS in the context of regional and national studies. Each issue is relevant over large geographic areas of the United States, has implications for water-management decisions, and raises significant questions best addressed through Tong-term scien- tific research. · Aquifer management: optimizing groundwater extraction while limiting undesirable effects such as salt-water intrusion, land subsidence, and harm to ecosystems, Aquifer storage and recovery (ASR) projects: use of aquifers for repeated storage and recovery of water of varying quality, Groundwater recharge: quantifying rates, spatial locations, and mechanisms of recharge from local to regional scales, · Surficial aquifers: evaluating hydrogeology, water-level changes, and water quality changes, Interaction of groundlwater with surface water: researching pro- cesses and mechanisms in wetlands, rivers, lakes, and coastal areas, o Flow and transport in karst and fractured aquifers: under- standing pathways, identifying recharge areas, and characterizing prop- erties at different scales, and Characterization of heterogeneous aquifers at large and small scales: understanding links between geology and hydrogeology, and developing new characterization methodologies. REGIONAL. AND NATIONAL OVERVIEWS Conclusion: A regional and national synthesis effort in the USGS groundwater program must be integrated with other programs to be suc- cessful. The current 2 percent of the USGS Water Resources Division (WRD) budget allocated to the groundwater resources program is insuf-
Conclusions and Recommendations 111 Ancient to do much more than identify project areas, coordinate projects, and disseminate information. A meaningful national groundwater pro- gram must therefore take advantage of many WRD resources, including the Federal-State Cooperative Water (Coop), National Research, Toxic Substances Hydrology, and NAWQA Programs, and other relevant ac- tivities. Studies will necessarily be interdisciplinary. They will likely involve collaborative work with scientists from other divisions of the USGS. Many of the studies will be of such scope and complexity that expertise from outside the USGS may be required. Partnerships with other federal or state science agencies and with research universities through the Water Resources Institutes would likely prove advantageous. Conclusion: The USGS needs a clear administrative method for setting priorities and choosing issues and regions for study in the context of na- tional synthesis. The current decision process is not clear to the com- mittee, and it may not be understood by many USGS district staff. Many issues and regions of the United States are appropriate for study, but in an era of limited resources, the USGS needs to make difficult choices in allocating resources to some issues and regions over others. The frame- work for making these decisions is not addressed in the current WRD StrategicPlan(USGS,1999c). In addition, there is a need for improved coordination of research efforts and data collection with federal, state, local, and private organizations outside the USGS and with universities and state geological surveys as well.
112 Investigating Groundwater Systems ACCESS TO GROUNDWATER INFORMATION Conclusion: Regional groundwater investigations have the comple- mentary goals of developing new scientific knowledge and translating that knowledge into information relevant for decision-making and policy for~nulation at regional and national levels. The proposed National Aq- uifer Database, with availability over the Internet, is one mechanism for making study results widely available. However, this database alone will not fill the need for synthesis of the scientific findings; instead, it will provide support and documentation for those findings. The synthe-
Conclusions and Recommendations ~3 sis and the interpretation of findings need to occur on two levels: (~) technical scientific summaries of research findings and (2) interpretive summary and synthesis publications aimed at providing information to decision-makers. Conclusion: As building blocks for national synthesis, most of the pri- ority issues outlined in this report will require many studies over many years. Consequently, data management is a critical part of the regionali- zation effort, especially in an era of rapidly changing data-management and storage technologies. Conclusion: Now, and in the future, the USGS will be expected to maintain and make available both primary and interpretive groundwater data in digital formats. With the existing USGS Internet sites and such electronic platforms as the National Atias of the United States, the main elements for a web-based data and metadata delivery system are already in place.
114 Investigating Groundwater Systems Conclusion: There is an ongoing need for expert interpretation and ex- planation of groundwater information at the local level. The integration of place-based groundwater studies into regional investigations must ultimately produce information and implications relevant to local water managers and individual citizens. These interpretations are often best provided by individual scientists familiar with the local issues and with local hydrogeology. METHODS DEVELOPMENT Conclusion: Physically based process models are essential for region- alization of groundwater information. Understanding physical proc- esses, the variations in parameters controlling those processes, and the uncertainty of predictions is essential for investigating groundwater sys- tems at regional scales. The USGS expertise in model development is well known. Recent advances in model visualization, links to GIS, pa- rameter estimation, uncertainty modeling, and optimization provide powerful new tools to the hydrogeologist.
Conclusions and Recommendations ~5 Conclusion: One of the most fruitful methods of regionalization and synthesis may be increased emphasis on the links between geology and hydrogeology (e.g., Leahy and Lyttle, 1998~. Geology exerts a funda- mental control on hydrogeologic processes, and regional variations in geologic setting offer an obvious starting point for regional groundwater studies.