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5 Delivery and Accessibility of Groundwater Data Nationally, the U.S. Geological Survey (USGS) has been and con- tinues to be an important source for credible groundwater data. Regional investigations may involve either the collection of new data and/or the compilation of existing data from state geological surveys, city and county agencies, regional authorities, well drillers, and previous USGS studies. Once assembled, these data have value far beyond their imme- diate use for a specific study. The opportunity exists to make these compiled data along with maps and reports generated by the project itself available to other public and private-sector data users working on local, regional, and national projects. The posting of physical and chemical ground~water information in easily accessible formats should, therefore, be an integral part of regional studies, dlespite budgetary Pressures. In this discussion we distinguish between raw or primary data, which is the collection of numeric data from various kinds of measure- ments, and interpretive data. The inflation content of data depends on the current state of understanding of the behavior of the system being measured and on the skill of the interpreter in extracting understanding from the data. The USGS publishes both primary and interpretative data. Some of the data the USGS publishes (e.g., water-level measurements in wells or piezometers) are only slightly modified from the original measurements. Groundwater data for individual wells are available as time series of these measurements. Interpretation of these data often requires addi- tional information about the site (local and regional pumping rates, etch Many of the data published by the USGS are at least partly interpretive. 99
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100 Investigating Groundlwater Systems A common example would be hydraulic conductivity or transmissivity estimates from aquifer-test data. Because methods of analysis change over time, it is essential that the USGS make raw data (such as draw- down as a function of time for an aquifer test), test procedures, and as- sumptions accessible and linked to the derived data such as transmissiv- ity. USERS OF GROUNDWATER DATA Groundwater data users are a diverse group having many different information needs. The same data may have multiple applications, in- cluding applications in science, engineering, planning, education, risk assessment, and many other fields. As shown in Table 3-1, users include water resources managers and agencies, agricultural producers, private industry, researchers, federal agencies, policy makers, planners, the me- dia, educational institutions at all levels, environmental groups, state and local cooperators, and private consultants. Although these different user groups may want access to the same data, they may have different inter- ests and abilities to find and manipulate data. The scale of interest also varies from user to user. A community activist may be interested in the water chemistry from a single industrial site or a suite of community wells, whereas a policy-maker may require information about groundwater resources on regional or even national scales. The requirements of the users vary vastly as well. Elementary school students studying the hydrologic cycle may make best use of re- gional or national hydrologic data in an aggregate form as charts, graphs, and tables. A researcher or consultant investigating hazardous chemical migration at a particular location might require primary chemical and hydrologic data with a full array of metadata (e.g., sampling protocol, analytical method, drilling method). Finally, USGS cooperators often have unique data needs specified in their cooperative agreement with the USGS, such as groundwater-level or chemical data at specific locations. These requirements may or may not be of interest to others, although they are more likely to be broadly useful if compiled into existing databases. Efforts to serve local needs through cooperative agreements should continue to be monitored to en- sure that these agreements complement and supplement the national data effort rather than compete with it.
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Delivery and Accessibility of Groundwater Data 101 The USGS has the challenge of supplying information to this wide range of users with their diverse data needs. This requires a concerted and broad-based effort to make information delivery including expla- nation, demonstration, and follow-through an integral part of regional studies. Several different media are discussed later in this chapter, but direct forms of communication should not be neglected. Regional proj- ects should include a designated liaison or a liaison committee to meet periodically with the local stakeholders. For example, Survey scientists and their cooperators should strive to participate in public meetings and workshops to explain project results and their implications, to demon- strate data access, and, most importantly, to get feedback on the infor- mation needs of the stakeholders. CONTENT OF GROUNDWATER DATA Depending on the study, groundwater data may include water-level measurements, water chemistry and water quality parameters, the results of aquifer tests, and other hydrogeologic parameters (e.g., aquifer thick- ness, mineralogy, recharge rates, porosities, leakage rates, and stream baseflows). Although the content of groundwater data will differ from site to site and from study to study, it should always include good meta- data, following accepted metadata standards such as Federal Geographic Data Committee Content Standard for Digital Geospatial Metadata (http://www.fg~c.gov/metadata/contstan.htmi). Metadata for wells or piezometers should include information such as well location, depth, outer diameter, inner diameter, screened interval, construction details, date drilled, owner's name, and geophysical and lithologic data. Infor- mation on local topography, springs, and streams is also important if available. Water-level and water quality measurements should indicate the nature of the measurements and the time the measurements were made so that time series of the data may be generated. To facilitate data flow between regional and local studies, data should include explicit information on measurement scale. Data from individual observation wells should contain a pointer to available local, aquiferwide, and regional data, including groundwater usage informa- tion, hydraulic characteristics, aquifer characteristics, and geologic in- formation. "Effective" values (e.g., the effective transmissivity for an entire aquifer) should include a clear delineation of the area that is in-
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102 Investigating Ground~water Systems eluded in the analysis, links to the primary data used to develop the ef- fective values, and assumptions made in the data analysis. FORMAT OF GROUNDWATER DATA Data-storage technology is rapidly evolving as new and improved means of electronic data storage are made available. A cursory survey of USGS Internet sites shows data available for distribution on paper, microfiche, diskettes, CD-ROM, DVD-ROM, and other media. Some of these media, or their successors, will continue to be used in the future. For example, prepared data sets for educational or outreach purposes are easily prepackaged and mailed on CDs. Paper copies have stood the test of time, are virtually independent of technology changes, and are clearly the best medium for large regional or national maps. Thus, the USGS must continue to provide groundwater data and the products derived from it through a variety of media. The Internet has revolutionized data delivery. Not only is it fast and efficient, but it also minimizes obsolescence of the transfer medium by transferring the data directly to the user's computer or network. Indeed, as of late 1999, the USGS was serving more than 7 million web pages per month to more than 200,000 users. Of the national surveys in indus- triaTized countries (e.g., British Geological Survey, Geological Survey of Japan, Bureau de Recherches Geologiques et Minieres "France], Geo- logical Survey of Canada, and Australian Geological Survey Organiza- tion), the USGS appears to be the leader in providing information over the Internet. Excellent examples of web-based data delivery already exist on the USGS servers. Some of these are products of the USGS Water Re- sources Division (WRD); others reflect broader efforts within the USGS. These examples are found at both national and regional scales. A num- ber of these web-based data delivery sites are discussed in the next sec- tion. Web-Based Data Sets on a National Scale Web-based data sets on a national scale include the following:
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Delivery and Accessibility of Groundwater Data 103 · National Atlas of the United States (http://www.usgs.gov/atias). The National Atlas of the United States~irected by the USGS is a cooperative effort with many federal and private organizations. Coop- erators include the Departments of Interior, Agriculture, and Commerce and the Environmental Systems Research institute (ESR0. Map layers are grouped by theme or discipline. Under the theme "water" are map layers for dams, watersheds, principal aquifers, real-time streamflow stations, and streams and other water bodies. Under the theme "envi- ronment" are layers for Superfund sites, nuclear sites, and many others. Layers can be displayed or downloaded as compressed ArcView shape- files. Furthermore, the maps are "cTickable," so real-time streamflow data for a given site can be accessed directly. Aside from the regional- scale "principal aquifers" layer cited above, however, groundwater in- formation is nonexistent. The availability of groundwater data would improve the "water" theme in the Atlas. · Real-time and historical streamflow data. Real-time and historical streamflow data are provided at two user-friendly sites: http://- water.usgs.gov/realtime.html and http://waterdata.usgs.gov/nwis-w/US/. The national maps shown on the main screen in these databases are cTickable down to the state or county level, where there is a listing of stream gauges linked directly to downIoadable data, metadata, and graphs. These databases are a resource to the nation and represent the type of data presentation we would like to see for groundwater data and other USGS WRD data. At present, there are no links at any level to other kinds of USGS WRD data (water quality data, etc.~. Further, no physical or chemical groundwater data are available currently in this format. · The National Water-Quality Assessment (NAWQA) Program summary of national groundwater and surface water quality data. The NAWQA Program has a summary of national groundwater and surface water quality data on its home page: http://water.usgs.gov/nawqa/. This page currently serves to highlight the individual regional NAWQA studies and the national syntheses that were derived from these studies. Web-Based Data Sets on Regional Scales At present, the availability and the quality of regional-scale infor- mation vary considerably across the country and are largely dependent
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104 Investigating Groundwater Systems on the efforts of individual USGS offices and their state and local coop- erators. Most USGS district offices maintain home pages with Internet links to state geological surveys, universities, and regulatory agencies. These USGS district or state web pages can be found indirectly by going to the national web pages and clicking on an individual state or region. Web-based data sets on regional scales include the following: · Web sites of NAWQA study units. NAWQA study units are by definition regional-scale studies; thus, their web sites present regional data. Some of the NAWQA study units have excellent web sites. The sites can be accessed from cTickable maps on the NAWQA home page. The NAWQA regional web sites are of variable quality. Examples of web sites that convey a significant amount of data include the Al- bemarie-Pamlico NAWQA site (http://sgildncrig.er.usgs.gov/albe- htmI/ALBEpage.htrnT), which has data, maps, video, pictures, and publi- cations from the study unit, plus educational activities. Other informa- tive sites include the lower TIlinois basin NAWQA site (http://www- il.usgs.gov/proj/lirb/~. Unlike the surface water sites discussed previ- ously, most maps presently are not georeferenced and are therefore not clickable. · Regional databases. Excellent regional databases also exist on the web. For example, the USGS Scientific Assessment and Strategy Team (SAST) database on the Upper Mississippi and Lower Missouri river basins (http://edcwww2.cr.usgs.gov/sast-home.htmI) was designed and built for a study of the flood of 1993 by a team from the USGS, Natural Resources Conservation Service, U.S. Arrny Corps of Engineers, U.S. Fish and Wildlife Service, U.S. Environmental Protection Agency, and Federal Emergency Management Agency. Although it is now somewhat outdated, this database has different kinds of geological, biological, hy- drological, and soil maps that can be viewed online or downloaded in various GIS formats. · Recent reports of regional studies. Recent reports of regional studies have been published on the web. The USGS Water-Resources Investigations Report 99-4000 Lithogeochemical Character of Near- Surface Bedrock in the Connecticut, Housatonic, anal Thames River Ba- sins (http://water.usgs.gov/pubs/wri/wri994000/~emonstrates the po- tential of the web for directly publishing the results of regional studies. In fact, the web is its principal medium of dissemination. The main product of the report is an ArcInfo-based lithogeochemical (i.e., units
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Delivery and Accessibility of Groundwater Data 105 expected to have a characteristic groundwater chemistry) map with asso- ciated metadata. The maps can be viewed as PDF files or can be down- loaded as Arcinfo export files or ArcView shapefiles. These georefer- enced formats would allow the user to overlay layers with other infor- mation in the region such as water well chemistry or water levels. Recommendations for Internet-Based Groundwater Information Delivery The primary elements for an excellent web-based data and metadata delivery system for groundwater are already in place. Our recommenda- tions would combine the best features of the sites described above. The National Atlas of the United States would make an excellent platform for most groundwater data. The Atlas (1) is run by the USGS but contains a wide variety of information from different agencies, (2) is national in scope, but the layers can also be zoomed down to a state or local scale, (3) is capable of displaying points such as wells, lines such as streams, and polygons such as outlines of regional groundwater proj- ect domains or welThead protection areas, (4) has a thematic structure that would allow related groundwater information to be found and ac- cessed easily, (5) already has a Real-time Streamflow layer that could be used as an analogue for well or piezometer data, and (6) is GIS-based so that map layers can not only be seen online, but can also be downloaded for processing with a PC or workstation-based GIS. Separate map layers would exist delineating ongoing and completed assessments of the NAWQA, Regional Aquifer-System Analysis (RASA), Toxic Substances Hydrology (Toxics), and Federal-State Co- operative Water (Coop) Programs and of regional groundwater pro- grams, with each polygon being linked to a project site containing geo- referenced data and maps as well as online reports. Many of these sites already exist and are accessible through the state USGS offices. How- ever, the Atlas would simplify the information search for the user by placing the information in the same general location. Older reports might first be available only as scanned images or PDF files, but primary data from these reports should be made available in digital format when feasible. It is also hoped that over time, USGS Water-Resources Inves- tigations Reports could also form a layer in the Atlas and be cross- referenced by watershed and county. New projects could be linked from their inception to all of the appropriate layers.
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106 Investigating Groundwater Systems Study results such as maps of modeled water tables or transmissivity distribution should be available not only in formats suitable for viewing online, but also in georeferenced formats that can be read by off-the- shelf GIS packages. This should not be time-intensive, as the major groundwater modeling codes are increasingly able to export results to one or more of these formats. A layer composed of well locations could be linked to its corre- sponding water-level data in a way analogous to the existing system for streamflow data. Data on groundwater (and stream) chemistry comprise a major part of the Survey's water resources data collection effort, and these data should be linked with other hydrologic data as technology permits. National studies could be catalogued in a separate layer in the Atlas. The proposed National Aquifer Data Base could also become a part of this system. Thus, information for a given state, county, or watershed at scales ranging from a point to a national summary could be located with minimal difficulty. In order to facilitate timely information delivery and communication between scientists, most ongoing regional and national investigations with a length of two years or more should establish a project web page that includes a description of the project, identification of project inves- tigators and cooperators, project location, anticipated final and interim products, and data availability. Such web sites should also include, where appropriate, online project reports and links to georeferenced pro- ject databases. These project web pages should be directly linked to re- gional and national data sets through the National Aquifer Data Base. Final reports for all projects should be available digitally in PDF or equivalent portable file formats. With the easy availability of digital data sets, the USGS and individ- ual scientists working for it will experience increasing pressure by plan- ners, consultants, and others to release data sets, model results, model input files, and other information prior to final publication of the project results and without the lengthy, formal peer-review procedure. It is rec- ommended that the USGS make data available as soon as possible with appropriate disclaimers and metadata documenting the preliminary data released. A precedent for this was established by web publication of the real-time streamflow data.
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Delivery and Accessibility of Groundwater Data CONCLUSIONS 107 The USGS should continue to develop its ability to communicate information regarding regional groundwater systems to decision-makers and the general public through the rapidly developing electronic media as well as through traditional means. Existing USGS web-based tem- plates for surface water data and map layers can be adapted for ground- water data and maps and their metadata. New clelivery methods should be publicized on the USGS home page ant! be backed by technical sup- port from staff of the Earth Science Information Centers. The USGS enjoys a reputation for providing value-neutral free or low-cost primary and interpretive data for public use on natural resources issues. It is es- sential that this reputation be protected and that the USGS continue to be a reliable and unbiased source of data and information.
Representative terms from entire chapter: