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Data Elements


                 U.S. Environmental  Protection Agency
                 Minimum  Set of Data Elements
                 for  Ground Water Quality -
                 The protection of our nation's ground water resources is receiving widespread
                 attention at all levels of government as the need to protect this vital resource
                 becomes increasingly clear.  As a part of the Environmental Protection Agency's
                 (EPA) continuing commitment to protect the Nation's ground water resources,
                 through implementing EPA's Ground Water Strategy1, the Agency has identified
                 a critical need to improve the management of ground water information.  EPA's
                 Ground Water Strategy recommends standardizing the type and quality of ground
                 water data collected to improve the accessibility, accuracy and consistency of
                 these data.  To facilitate this effort, EPA's Office of Ground Water and Drinking
                 Water, with the help of numerous State and Federal .officials, has established a
                 Minimum Set of Data Elements for Ground Water Quality (MSDE). The
                 MSDE is comprised of two parts: (a) EPA Policy Order 7500.1A, October 1992
                 and (b) the guidance document, Definitions for the Minimum Set of Data
                 Elements for Ground Water Quality, EPA 813/B-92-002, July  1992.

                 The MSDE is "the minimum number of elements necessary to use ground water
                 quality data . . . across related programs." It is a set of 21 ground water quality-
                 related data elements that contain geographic, well and sample descriptors.
                 These data elements form a standard data set that EPA and  States can use to
                 support better environmental decision-making and promote the integration of
                 related environmental programs. The following pages list the elements and their
                 definitions that comprise the MSDE.
                 The purpose of the MSDE is to help standardize the collection and storage of
                 ground water quality data to allow the efficient management and sharing of these
                 data. By standardizing the type and quality of ground water data that are
                 collected, the MSDE supports the EPA's goal to improve the access, accuracy
                 and consistency of ground water data. It also supports the use and transfer of
                 ground water data between EPA, the States, municipalities and other Federal
                 agencies. The MSDE will help achieve the data management goals of programs
                 such as the Wellhead Protection (WHP) Program as included in the Safe
   1 U.S. EPA, protecting the Nation's Ground Water:  EPA's Strategy For the 1990s, EPA/21Z-1020,
July 1991.

              The Minimum Set of Data Elements for Ground Water Quality

   The MSDE is comprised of 21 data elements that are divided into the following four categories or
descriptors: the general descriptor  describes where the well information is maintained; the
geographic descriptors  describe a well or spring in relation to the earth's surface; the well
descriptors  describe various features of a well or spring; and the sample descriptors  describe
different aspects of collecting, analyzing and recording the results of a  ground water sample.

General Descriptor

1. Data Sources - The names of the organizations to direct questions regarding the following data:
(1) latitude and longitude coordinates, (2) altitude, (3) well log information, (4) sample collection and
(5) laboratory sample analyses.

Geographic Descriptors

2. Latitude - A coordinate representation that indicates a location on the surface of the earth using
the earth's equator as the latitude origin, reported in degrees (D), minutes (M), seconds (S) and
fractions of a second in decimal format (if fractions of a second are available).  A "+" (plus) symbol
represents latitudes north of the equator.  A"-" (minus) symbol represents latitudes south of the

3. Longitude -  A coordinate representation that indicates a location on the surface of the earth using
the prime meridian (Greenwich, England) as the longitude origin, reported in degrees (D), minutes
(M), seconds  (S) and fractions of a second in decimal format (if fractions of a second are available).
A"+" (plus) symbol represents longitudes east of the prime  meridian.  A"-" (minus) symbol
represents longitudes west of the prime meridian.

4. Method Used to Determine Latitude and Longitude - The procedure used to determine the latitude
and longitude coordinates (Technology of Method Used), the standard used for three dimensional and
horizontal positioning (Reference Datum), the method used  for map interpolation (Scale of Map) and
the date on which  the coordinates were determined (Date). Latitude always precedes longitude.

5. Description  of Entity - A textual description of the entity to which the latitude and longitude
coordinate refers.

6. Accuracy of Latitude and Longitude Measurement - The  quantitative measurement of the amount
of deviation from true value present in a measurement (estimate of error). It describes the
correctness of a measurement.

7. Altitude - The vertical distance from the National Reference Datum for Altitude to the land
surface or other measuring point in feet or meters. If the measuring point is above the National
Reference Datum for Altitude, a "+"  (plus) sign shall precede the reported altitude value.  If the
measuring point Is below the National Reference Datum for Altitude, a "-" (minus) sign shall precede
the reported altitude value,

8. Method tteed to Determine Altitude - The method used to determine the altitude value (Altitude
Method)j the National Reference Datum on which the altitude measurement is based (National
Reference Datum for Altitude)  and the date the measurement was taken (Altitude Date),

        The Minimum Set of Data Elements for Ground Water Quality (continued)

Geographic Descriptors (continued)

9. Slate FIPS Code - A Federal Information Processing Standard (FTPS) alphabetic or numeric code to
indicate the location of the State (or its equivalent such as territory or province) in which the well is

10. County FIPS Code - A Federal Information Processing Standard (FIPS) numeric code to indicate the
location of the county (or county equivalent) in which the well is located*

Well Descriptors

11. Well Identifier - A unique well identifier assigned fey  the responsible organization,

12. Well Use - The principal current use of the well, or if the well 'is not currently in use, then the
original or principal purpose for its construction.

13- Type of Log - The type of record-keeping log(s) available for a well.

14. Depth ojf Well at Completion ~ The depth of the' completed well below the land surface or other
measuring point, in feet or meters.

15. Screened/Open Interval - The depth below the measuring point to the top and bottom of the open
section in a well reported as an interval in feet of meters. The open, section may be a well screen,
perforated casing; or open hole.

Sample Descriptors

16. Sample Identifier - A unique number for each water quality sample collected at a well (Sample
Control Number) which references the date (Sample Date), the depth at which each sample is taken
reported in feet or meters (Sample Depth)  and the time the sample is taken (Sample Time),

17. Depth to Water - The vertical distance between the measuring point and the water surface level at a
well, corrected to land surface, where the measuring point is not the land surface. This distance should
be reported in feet or meters (Measurement Depth), along with the date and time the measurement was
taken (Measurement Date and Measurement Time).

18, Constituent or Parameter Measured - Measurement of a physical, chemical or biological component
The physical, chemical or biological components are referred to as constituents or parameters.

19. Concentration/Value - The analytical results value, the units of measure used (Analytical
Concentration/Value) and the analytical method applied (Analytical Method) to the samples collected.

20. Analytical Results Qualifier - Qualifying information that will assist in the interpretation of the
concentration/value, such as whether the value is below the detectable limit or if the constituents
(parameters) of interest are present but cannot be quantified,

21. Quality Assurance Indicator - The quality assurance of the field protocol plan and laboratory quality
assurance/qualify control (QA/QC) procedures.

                   Drinking Water Act. The purpose of the WHP Program is to prevent
                   contamination of underground sources of drinking waten The MSDE will also
                   support Comprehensive State Ground. Water Protection,Programs2 (CSGWPPs)
                   as written in the EPA Ground Water Strategy. Through the CSGWPP initiative,
                   EPA is working with States to establish common ground water protection
                   priorities and better integrate and coordinate ground water protection activities.
                   EPA began developing the MSDE as a result of a Ground Water Data
                   Requirements Analysis conducted in 1987. An issue consistently identified during
                   this analysis was the need to improve access to ground water data and the need
                   to standardize data elements to increase information sharing capabilities. In
                   response to this need, EPA conducted a workshop in 1988 to discuss the
                   development of a minimum set of data elements for ground water quality.

                   The goals of the workshop were to achieve consensus on a minimum set of data
                   elements that would facilitate the collection and sharing of ground water data
                   across agencies and to identify implementation issues that must be resolved to
                   encourage collection of a MSDE throughout the ground water community.

                   Workshop participants used the following criteria to identify minimum elements:

                         The elements that are needed to communicate ground water data
                         across related programs;

                         The elements that are common to all programs and completely
                         adequate for some programs;

                     '    The elements that provide a path to other ground water data; and

                         Those elements that provide a link between ground water quality
                         and well location information.

                   EPA established an interim Policy Order in 1989 that made the use of the
                   MSDE a requirement for EPA and its contractors.  EPA issued the final Policy
                   Order (number 7500.1 A) in October, 1992.

                   The development of the policy! order and its accompanying guidance document
                   (that includes definitions, discussions and examples of use for each element in
                   the MSDE) involved an iterative process of drafting and peer review by a MSDE
                   work group of over 100 representatives from EPA, other Federal agencies  and
                   the States. The 21 elements that comprise the MSDE represent the minimum
                   data elements officials should consider when collecting ground water quality data.
                   They form the core upon which data managers can build data bases by adding
                   additional elements.
   2  U.S. EPA, Final Comprehensive State Ground Water Protection Program Guidance, EPA 100-R-
93-001, December 1992.

                  There are a number of benefits to adopting and using the MSDE.  The MSDE
                  ensures consistency in the type and quality of data collected by all users of this
                  data set. By collecting the same set of data elements that have established
                  definitions, members of the ground water community can easily share important
                  ground water quality data. Such sharing facilitates effective and efficient
                  information exchange within and between Federal, State and local programs.

                  As an example, one scenario follows:  A State water management agency is
                  planning to track trends in ground water quality in order to prioritize its ground
                  water management activities.  Historically, only limited data have been collected
                  from only a portion  of the State. Recently, however, the agency and other
                  members of the ground water community In the State have incorporated the
                  MSDE into their current data  management systems in an effort to develop a
                  solid base of information for a comprehensive information management system.

                  To collect the additional data that the State needs to complete its work, the
                  agency turned to others who collect ground water quality data (e.g., EPA RCRA
                  and CERCLA site managers, U.S. Geological Survey (USGS) personnel
                  conducting site-specific hydrogeologic assessments and local health and
                  environmental departments).  Since these other agencies collect the same MSDE
                  elements and define these elements in the same way, the State can add these
                  fundamental data to its now rapidly growing data base.  Use of the MSDE across
                  the State or nationally will help this State agency to access data bases to find
                  information before spending often scarce resources to implement an expensive
                  monitoring program.

                  Another benefit of the MSDE is to help States achieve formal endorsements  of
                  their Comprehensive State Ground Water Protection Programs (CSGWPPs)
                  from EPA. A MSDE is specifically referenced in the following adequacy criteria
                  for CSGWPP endorsement:

                     A minimum set of data elements is defined and used by all ground water-
                      related programs within the State to facilitate data sharing and cross media
                      analyses and provide users with consistent and comparable data.

                  Implementation of the MSDE will help EPA and States to efficiently measure
                  progress in and document the success of CSGWPPs and help States identify
                  ground water priorities, which  is an important component of a CSGWPP.
                   EPA Order 7500.1 A requires that all EPA staff and EPA contractors use the
                   MSDE for all ground water data collection activities, including research and
                   development and enforcement. In addition, EPA strongly encourages all
                   organizations that collect ground water quality data to adopt and use the MSDE.
                   Such organizations include State and local governments, EPA grantees, other
                   Federal agencies, the regulated community, associations and other members of
                   the ground water community.


                   Implementation of the MSDE is most important under the following conditions:

                      (1)  When States, Federal agencies or other officials are creating a new
                          ground water, quality data base; or

                    '  (2)  When officials want to modernize an existing data base because they
                          have a significant amount of new data or because they want to achieve
                          consistency with other data bases.

                   When implementing the MSDE there are a number of policy issues to consider.
                   First, formal recognition of the MSDE as an integral part of programs should be
                   considered during the reauthorization of related programs; however, the MSDE
                   policy does not require the modification of existing regulations.

                   Second, officials should consider the personnel  and other resources needed to
                   implement the MSDE. In many cases, most of the data elements in the MSDE
                   are part of existing ground water data bases and therefore implementing the
                   MSDE will likely require limited effort. In other cases, data management systems
                   may need some modification and staff may also need limited training.  The
                   resources necessary to implement the MSDE will depend on the specifics of each
                   existing data management system and the technical expertise of those in the field
                   who collect the data.


                   There are several key technical issues to consider when implementing the MSDE.
                   First, data should be expressed consistently. For example, data formats need to
                   be uniform. Also, data need to be expressed in the same units of measurement
                   (e.g., feet or meters), for all relevant data elements.  EPA is prescribing data
                   formats in the MSDE for a limited number of elements to ensure conformance
                   with EPA and Federal government policies. For most of the elements in the
                   MSDE, however, EPA does not prescribe but rather suggests data storage
                   conventions.  In the guidance document, EPA presents the preferred data
                   storage format for each element as the first data convention example.

                   Secondly, related data should be linked together. Similar data elements can be
                   grouped into what are called "entity" filesl  Entity files related  to the MSDE are
                   wells and  other ground water locations, samples and analytical results. Each
                   element in the MSDE fits into one of these .three entity files.  Organizing data by
                   entity, files improves the efficiency of a data base's storage capabilities.

                   Lastly, data fields should be stored separately.  Data elements  that contain two or
                   more values representing distinct pieces of information can be stored in different
                   fields to increase the flexibility of a data base.  For example, the Sample
                 ,  Identifier element is comprised of the date, time and depth the sample was taken
                   in addition to a unique sample control number.  Storing each component
                   separately makes it easy to correct data errors and will help minimize difficulties
                   in tracking the sample and linking data should corrections be 'necessary.

                    EPA amended the 1989 MSDE Policy Order to reflect the definitions for each '
                    data element and to clarify when EPA and EPA contractors must implement the
                    MSDE. EPA has also met with various State and Federal groups to explain the
                    benefits of using thfe MSDE.  If you are interested in discussing implementing the
                    MSDE in your data system, call the EPA Ground Water Protection Division
                    MSDE Coordinator, at (202) 260-7077.

                    In response to the Order, EPA is including the MSDE in its Federal Reporting
                    Data System (FRDS) and its STOrage and RETrieval System (STORET)3.
                    Currently  undergoing major redevelopment, FRDS is an automated data base
                    supporting the Public Water Systems Supervision Program operated by EPA's
                    Office of Ground Water and Drinking Water. This data base is a repository for
                    data on public water supplies and compliance monitoring requirements and
                    regulations of the Safe Drinking Water Act Amendments of 1986.

                    STORET, one of the oldest and largest water information systems, is also
                    undergoing a major modernization that is expected to continue  for the next five .
                    years.  STORET forms the basis for many other water information systems and
                    has served as a standard for the design of many State water information systems.
                    STORET contains information on ambient, intensive survey, effluent and
                    biological water quality monitoring information.  As part of the  FRDS
                    redevelopment, ground water data from FRDS will'be linked to ground water
                    data in STORET. Designed to reside on EPA's mainframe computer,  the
                    modernized STORET will provide enhanced capabilities to describe the more
                    than 150 million parametric observations currently residing within the system.
                   STORET is jointly maintained by EPA's Office of Information Resources
                   Management and the Office of Wetlands, Oceans and Watersheds.

                   The inclusion of the MSDE in FRDS and STORET is expected to greatly
                   increase the utilization of ground water data between EPA programs and
                   Federal, State and local agencies. For instance^ locating public water supplies
                   and linking them to STORET ambient and source-specific monitoring data may
                   assist in setting priorities for ground water programs and in characterizing source-
                   contaminants for the development of drinking water standards.

                   In addition to  this brochure, EPA ha.s also developed an internal fact sheet (for
                   EPA and EPA contractors) and an external fact sheet (for States, EPA grantees,
                   other Federal Agencies) to promote the implementation of the MSDE. The
                   internal fact sheet focuses oh how the MSDE can help standardize  and improve
                   the sharing of ground water information within the Agency. The external fact
                   sheet discusses how the MSDE can help (1) States meet one of  the adequacy
                   criteria for a CSGWPP, (2) States achieve approval of their WHP Program and
                   (3) Federal agencies share information more effectively.
   3  For more information on FRDS, contact Jeff Sexton at 1(202) 260-7276. For more information
on STORET, contact Bob King at (202) 260-7028.                 .   .  -,                  -

Minnesota and
the MSDE4
Historically, ground water data collected by the Minnesota Pollution Control
Agency (MPCA) programs were stored in a variety of data bases and formats
that made accessing and sharing these data difficult. More than seven years ago,
program development personnel at MPCA recognized the advantages of a central
repository for ground water quality data collected by a variety of MPCA
programs. The MPCA envisioned its central data repository as a model for other
ground water information systems developed within Minnesota and elsewhere.
This comprehensive system would enhance MPCA's ability to collect, access,
share and utilize ground water information among multiple program areas.  This
system, the Integrated Ground Water Information System (IGWIS), became
operational in August 1990.

The MPCA had already established standards for the collection of ground water
data, but as the MSDE developed, the Agency adopted MSDE elements not
already included in IGWIS.  The MPCA recognized the benefits of including
these critical elements in any comprehensive data base.  Establishing data
collection standards and centralizing data has helped MPCA integrate data from
various programs and resulted  in the following cross-program benefits:

       Minnesota's Ground Water Monitoring and Assessment Program
       (GWMAP) can use other MPCA programs' upgradient wells to
       evaluate regional ambient water quality conditions;

      The GWMAP can also use other programs' data to track low level
       contamination in areas of widespread contamination;

      Regulators can compare site data to data on nearby wells monitored
       by other MPCA programs to determine if action is necessary; and

      Access to a collective data base enables MPCA programs to better
       understand the geology, ground water flow and  contamination levels
       within a given area and should reduce the need to install additional
       sampling stations or  perform additional sampling events.

IGWIS consists of the following three components that parallel the descriptor
categories of the MSDE:

       The Facility component stores general descriptive information about
       each facility including name, location, owner, type of facility, the
       requirements for ground water monitoring and effective dates, and
       facility remarks.

       The Station component contains detailed information about specific
       sampling stations including location, construction and installation
       information, geologic characteristics and station remarks.
   4  For more information on IGWIS, contact either Susan Schreifels at (612) 296-8581 or Shelly
 Street at (612) 296-7318.

 Idaho and the
        The Sample component CO,
        sampling event, the samples taken ana the results of. analyses on*" those
      ,  samples. .,..-.,..-.. ;>

 IGWIS is a mainframe system,and was designed as a user-friendly, menu-driven,
 multi-user, relational data base that has a number of capabilities.  These
 capabilities include on-line validation of data, journaling of critical fields,
 electronic conversion of locational coordinate systems, automatic calculation of
 data, standard and user formatted queries and security and data confidentiality
 provisions.  Data are entered manually from data collection, forms and in the
 future IGWIS will also allow electronic transfer of data. Outputs include
 standard  reports and electronic data sets that can be interfaced with other
 software  applications.

 Data stored in IGWIS can be used for ground water modeling, hydrogeologic
 mapping, geologic cross-sections, fence diagrams, contaminant distribution
 mapping, three-dimensional plotting, statistical analysis, trend analysis and
 Geographical Information Systems.

 The Idaho Department of Health and Welfare, Division of Environmental
 Quality is in  the final stages of completing a major modification of their water
 quality data information-system. Scheduled for completipn in Spring 1994, the
 Drinking  Water Information Management System (DWIMS) will serve as a
 comprehensive data base system for drinking water, surface water and ground
 water data.  This personal computer-based system is  designed to serve the needs
 for specific water resource data and reporting requirements needs of regional and
 field offices.  It also supports other State programs.

 The DWIMS is designed to incorporate the MSDE.  It includes multiple modules
 that will enhance Idaho's ability to interact with other State ;and Federal data
 systems.  In addition to the generation of standard data reports, the inclusion of
 the MSDE into DWIMS  will help Idaho to report public water supply data to
 the EPA  Data in DWIMS resides in dBase, and the system software is written
 in Clipper.
The USGS and
the MSDE6
The USGS is in the process of redesigning its hydrologic data management
system and has included the MSDE as one of its features.  The new data
management system, named the National Water Information System II (N-WIS--
II), will integrate the current distributed data processing functions of NWIS-I, the
central data base and archival functions of the national Water Data Storage and
Retrieval System (WATSTORE) and the water data index'functions of the   '  
National Water Data Exchange (NAWDEX).
   5 For more information about DWIMS, contact either Steve Dempsey at (208) 334-0414 or
Derek Thomas at (208) 334-0484.

   6 For more information about NWIS-II, contact Tom Yorke at (703) 648-5659.

                  NWIS-II integrates more than 13 major data files including water quality, ground
                  water site characteristics, water uses, stream and sediment discharge and basin
                  characteristics. NWIS-II will also have an expanded capability for processing and
                  storing additional sediment, biological  and spatial data. The comprehensive and
                  integrated architecture of NWIS-II provided the capability to incorporate the
                  MSDE and to facilitate the exchange of data between the USGS and EPA and
                  other agencies.

                  The objectives of NWIS-II are to develop an integrated, multidisciplinary data
                  base that will:

                         Provide a comprehensive data  management system to support the
                         USGS's Water Resources Division's mission to appraise the nation's
                         water resources;

                         Serve as an archive for all data used in completed and published
                         products of the USGS; and

                         Provide a national index for water data.

                  NWIS-I is maintained on PRIME minicomputers at 54 locations nationwide;
                  WATSTORE and NAWDEX are maintained on an Amdahl mainframe computer
                  in Reston, Virginia.  The data processing, storage and management functions of
                  NWIS-II will be fully distributed on a  network of 32-bit workstations with UNIX
                  operating systems.

                  NWIS-II will be released in two stages. The first release, which will include data
                  processing and management of water  quality, ground water and biological data,
                  will occur in April 1993. The streamflow, sediment and water use components of
                  the system will be released in October 1993.


                   More information on the MSDE can  be found in the following documents:

 Guidance       Definitions for The Minimum Set of Data Elements for Ground Water Quality,
 Document        EPA 813/B-92-002, July 1992.

 Fact Sheets
EPA Policy Order No. 7500.1A, October 1992.

Minimum Set of Data Elements for Ground Water Quality / Fact Sheet on
Implementation for EPA and EPA Contractors

Minimum Set of Data Elements for Ground Water Quality / Fact Sheet on
Implementation for States, Local Governments, Tribes, Federal Agencies,
Grantees, Associations and the Regulated Community

 Copies of these MSDE documents may be obtained by cogggg mn
                                       U.S. Environmental Protection Agency
                                          Safe Drinking Water Hotline

 or by writing:

                                       U.S. Environmental Protection Agency
                            Office of Ground Water and Drinking Water Resource Center
                                       401 M Street, SW, Mail Code RC-4100
                                             Washington, DC 20460

 Additional        Codes for the Identification of the. States, the District of Columbia and the Outlying
 References       Areas of the United States and Associated Areas, Federal  Information Processing
                   Standards (FTPS) Publication 5-2, M:ay 1987.

                   Counties and Equivalent Entities of the United States, its Possessions and
                   Associated Areas, Federal Information Processing Standards (FIPS) Publication
                   6-4, August 1990.

                   Information Resources Management Policy Manual  Locational Data Policy, U.S.
                   EPA Office of Information Resources Management, April 8, 1991.

                   Locational Data Policy Implementation Guidance  Guide to The Policy,
                   EPA/220/B-92/008, March 1992.

                   Locational Data Policy Implementation Guidance  Guide To Selecting Latitude/
                   Longitude Collection Methods, EPA/220/B-92/009, March 1992.

                   Locational Data Policy Implementation Guidance  Global Positioning Systems
                   Technology and Its Application in Environmental Programs, EPA/600/R-92/036,
                   February 1992.

                   EPA Order 2180.3  Facility Identification Data Standard, U.S. EPA Office of
                   Information Resources Management, April 9, 1990.

                   Facility Identification Data Standard Implementation Plan, U.S. EPA Office of
                   Administration and Resources Management, February 1992.
Further information on the additional references may be obtained by calling or writing:

                                      U.S. Environmental. Protection Agency
                                              Headquarters Library
                                               401 M Street, SW
                                             Washington, DC  20460
                                                 .(202) 260-5922