- What is the County Well Index?
The County Well Index (CWI) is a database system developed by the Minnesota
Geological Survey (MGS) and the Minnesota Department of Health (MDH) for the
storage, retrieval, and editing of water-well information. The database contains
basic information on well records (e.g. location, depth, static water level)
for wells drilled in Minnesota. The database also contains information on
the well log and the well construction for many of the wells.
- Is this information available to anyone?
- What kind of computer do I need to run CWI?
A computer running Windows 95, 98, ME, NT, 2000, or XP with a minimum of 64mb
ram and 350mb of available disk space. It will run on a machine with a 166mhz
processor, but, as might be expected, a faster processor will deliver a more
- Is there a Macintosh version of CWI?
No, although it may be possible to get it to work with a Windows emulator
such as SoftWindows running on the Mac. This has not been tested.
- Who currently uses CWI?
CWI is used by a variety of state and local agencies, by private companies
interested in ground-water related issues, and by educational institutions
for research and educational purposes.
- Does the database include all wells drilled in Minnesota?
No. CWI is by far the most comprehensive database of water-well information
available, but contains only information for wells for which a log is available.
We estimate this to be about ten percent of all wells drilled. Most of the
records in CWI are for wells drilled since 1974, when the water-well construction
code required drillers to submit records for wells drilled in the state to
the MDH. CWI does contain data for some records obtained by the MGS through
the cooperation of drillers and local government agencies for wells drilled before 1974.
- How often is the information updated?
The database is updated continuously by the MGS and the MDH. CDs with the
database and retrieval software (cwi4VIEW) developed by Fuliao Li of MDH are
available for purchase. The data on the CDs are updated quarterly. The same
information contained on the CD is also available on the MGS ftp site (ftp://mgssun6.mngs.umn.edu/pub2/cwi4/
). The raw database (without cwi4VIEW) and a shapefile containing locations
for those wells that have had their locations field verified are updated frequently.
- How can I find out if my well is on the database?
If you have a copy of CWI, you can search the database based on Public Land
Survey (township, range, and section) or by well address or owner's name.
Keep in mind that the owner's name is (usually) that of the owner at the time
the well was drilled. Address searches also are often not successful since
small inconsistencies or errors in entry of the address or the search criteria
will cause the search to fail. If you do not have CWI, and are in the Twin
Cities area, you can stop by the MGS and a staff member will help you search
for your well. The Environmental Services office or Soil and Water Conservation
District office or other county office in your county may also have CWI available
and may be able to help you with database searches also.
- What else can CWI be used for?
cwi4VIEW provides a variety of ways to select, or sort, and list or report
information about wells. A group of wells can be selected based on a single
criteria of combination of criteria. For example, a user can select all wells
in a certain township, range, and section, that encounter bedrock within 50
feet of the surface, or wells that pump water from the Jordan aquifer. Once
the wells have been selected the information can be viewed on-screen, the
list printed, or reports generated for individual well records.
- Does the database include information in addition to that on the well
Yes. CWI can store static water level measurement data from any source for
a particular well. In this way, the data can be examined for changes or trends
over time. A CWI record also contains flags indicating whether geophysical
information is available for that well or if information about the well is
available in other state databases. Multiple, general "remarks" may be entered
into the database offering an opportunity to capture information about the
well that may not fit in the fields designed for the well record.
- Are only water-well records included?
For the most part, yes. Some exploratory boreholes along with records of monitoring
wells are being added to CWI.
- Can I edit the data?
No. CWI is provided to the public as a viewable database. However, we are
always trying to improve the quality of the database, so we would appreciate
hearing of errors found in the database (please include the unique number
of the well along with the information you believe to be in error, and email
to email@example.com ).
- Is it possible to get hard copy reports of the data?
Yes. cwi4VIEW includes a report writer that can generate a printed list of
a group of selected wells or full reports for each selected well log.
- Is CWI compatible with other database software?
CWI is currently storage as an Access database. Access provides a number of
export formats that allow transfer of the data to other database software.
- Is CWI compatible with geographic information systems (GIS)?
Yes. A shapefile containing locations and the main CWI table for wells that
have been field located and digitized is provided on the CDs and on the MGS
ftp site. Many GIS software packages are capable of reading the shapefile
format. Free software from the Minnesota Land Management Information Center
(LMIC) is available (http://lucy.lmic.state.mn.us/metadata/sectic.html
) that can convert the PLS information (township, range, section, subsection
) contained in CWI to Universal Transverse Mercator (UTM) coordinates, which
would allow plotting of well locations that are not included in the shapefile.
If this is done, however, care should be taken in making assumptions or interpretation
based on these locations since the accuracy is often not very good.
- How can I order CWI?
Stop by the MGS Map Sales office (2609 West Territorial Rd., St. Paul) or call
612-626-2969 and place an order with Map Sales. Please allow 2-3 business
days to process your order.
- How much does it cost?
CWI is available to the private sector for $15.00 plus tax and shipping. The
CD contains the complete CWI data for the entire state as well as the associated
- How can I receive updates?
As mentioned above, new versions of the CWI CD are created quarterly. For
most of the state, the dataset does not change very rapidly (i.e. not many
wells are drilled) and annual update may be satisfactory. In some high-growth
areas, however, more frequent updates may be desired. The basic procedure
is to simply purchase a new CD when an update is desired and, when the update
is received, uninstall the previous version before installing the new version.
Also, as mentioned previously, update are available through the MGS ftp site