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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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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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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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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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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:
water quality
