The data in this file was obtained from Wellogic, the Michigan Department of Environmental Quality Statewide Groundwater Database (SGWD). Wellogic contains approximately 425,000 water well records found within the State of Michigan, and although it represents the best available data, it cannot be considered a complete database of all the wells or well records in existence. The well files were downloaded by county and merged together to create a statewide file. In the merge process any well that fell outside of its designated county boundary was removed from the original data set. Approximately 325,000 records were used in this file after the inconsistent point locations were removed. A series of additional attributes were added to the database, this is a brief overview of how the well locations were processed:
A GIS data update utility created at MSU was used to process and merge the county wells; this also added many glacial drift and rock well fields, and percentages for aquifer drift material based on the existing Wellogic and lithology database information. Next the percentages of aquifer material and trend information were calculated for the drift index. These fields were used by the USGS to further calculate the wells transmissivity and yield values.