Database collections (both physical and digital copies) reside at the Minnesota Geological Survey (MGS) and are continually maintained and expanded upon by MGS staff as part of our mapping efforts. The BGD includes both logs generated by the MGS and those generated by third-parties and donated to the MGS collections.

BGD collections include the following:

Gamma logs (natural gamma radiation and typically single point resistance [abbrev. "RES" on logs] and spontaneous potential [abbrev. "SP" on logs])
Electrical logs (single point resistance and/or spontaneous potential)
Caliper logs (borehole diameter)
Multi-parameter logs (natural gamma radiation, fluid resistivity, spontaneous potential, temperature, normal resistivity, single point resistance, and specific conductivity)
Electromagnetic (EM) flowmeter logs (flowmeter, fluid resistivity, and temperature)

Including those collected during ambient, injected, and pumping conditions

Video logs (borehole video recordings)

This web map serves to make the BGD collections publicly accessible, providing users with direct access to digital PDF and LAS (Log ASCII Standard) copies (if available) of any log, and was made possible through funds provided by the United States Geological Survey National Geologic and Geophysical Data Preservation Program (NGGDPP) (Award Nos. G15AP00105 and G17AP00089) and cost-shared with matching funds from the MGS. Click here to visit the BGD web map landing page.

The BGD web map contains 8 different layers corresponding to each type of log collected, as well as a layer containing location-verified Water Wells pulled from the Minnesota Department of Health/Minnesota Geological Survey County Well Index (CWI) database.

Each BGD layer includes all of the detailed water well and logging information for that logging event, as well as direct download links to their PDF and LAS files. Log ASCII Standard (LAS) files are a standard file-format developed by the Canadian Well Log Society and common in the industry for borehole logs. Most borehole logging software can import and display LAS files.

Each layer also includes unit stratigraphy codes representing the first and last bedrock unit (if bedrock is present) encountered during logging as interpreted by MGS geologists in the days following data collection. These interpretations are considered historical data and may not represent the most up-to-date stratigraphic interpretation for any borehole. Users should always refer to the stratigraphic interpretations provided in the County Well Index for any particular water well record. Direct links to corresponding County Well Index water well log records and well stratigraphy records are included in the each layer.

Also, please note the following:

Due to security concerns, wells supplying public water systems that are currently active are not displayed on the BGD web map.
The location of each borehole geophysical record is based on the corresponding location data provided by the County Well Index. Any borehole geophysical record whose unique number does not match a corresponding water well unique number in the County Well Index is not included on this map.
The borehole geophysical log header information included in the PDF and LAS files is considered historical data. The static header information may not match the current information in the layer attributes. For the most up-to-date location and construction information, refer to the County Well Index.
To learn more about how the MGS uses borehole geophysical logs to distinguish hydrostratigraphic units in Minnesota’s Paleozoic bedrock and to better define the hydrogeologic framework see Hydrogeology of the Paleozoic Bedrock in southeastern Minnesota, Minnesota Geological Survey Report of Investigations 61 (Runkel and others, 2003).