NEW LIDAR-BASED INDIANA DNR POTENTIOMETRIC SURFACE MAPS

The Indiana Department of Natural Resources (DNR), Division of Water (DOW) began a new county-based potentiometric surface mapping project in 2011. A DOW customer survey conducted in 2010 showed that potentiometric surface maps were rated the most important future water resource product. The potentiometric surface project was begun upon completion of the county-based statewide aquifer systems mapping. As with groundwater availability mapping, the potentiometric surface mapping project relies heavily on the DOW water well database, which is freely available online and contains over 400,000 water well records. All of the DOW groundwater assessment maps and publications are posted on the Internet and are free for viewing, printing, and downloading from the DOW main page at http://www.in.gov/dnr/water. The new potentiometric surface mapping project utilizes airborne obtained LIDAR (Light Detection And Ranging) data for surficial high-resolution digital elevation maps (DEMs). The LIDAR obtained point elevations are assigned to located water wells within a Geographic Information Systems (GIS) program. The static water well level obtained from the water well record is subtracted from the surface elevation to obtain the potentiometric surface elevation. Geocoding was used in conjunction with county parcels and address points to increase the number of located water well records available for mapping. The products for the new potentiometric surface map series include: maps and digital coverage of unconsolidated and/or bedrock potentiometric surface lines; text describing potentiometric surface mapping; a spreadsheet of water well data used for potentiometric surface mapping, with a separate lithology tab; GIS shapefiles of pertinent geographic and hydrologic features displayed on the maps; and a potentiometric surface line Keyhole Markup Language compressed (KMZ) file.