A GEOSPATIAL APPROACH TO IMPROVE SUBSURFACE INFORMATION IN VERMONT

The Vermont Well Completion Report database contains well drillers’ reports from 1965 to present and hosts information which can be applied to geologic mapping, hydrogeologic studies, and quantifying Vermont’s reliance on certain water resources. The database of 116,000+ wells contains 64 fields including location, depth, static water level, and yield, in addition to subsurface information such as materials and thicknesses. These data are widely used by environmental consultants, government scientists, health professionals, university researchers, and homeowners. The Vermont Geological Survey worked over the past 15 years to update well locations as part of its mapping projects and generally located 15-30% of the wells in a mapping area. Due to the development of modern and historical digital datasets such as parcel data and imagery, this is now a separate process, completed before mapping begins, that can locate 30-60% of the wells in a mapping area. The method relies on a series of python scripts, using the pandas and arcpy libraries, to pull relevant information from the Well Completion Report database and compare it with integrated historical grand list and parcels data. This is a supervised approach where the user evaluates the available information in an interactive map and can change the location of the well in the database to match the house or property where it was drilled. Recent revisions to surficial geologic mapping in the Jeffersonville Quadrangle, Vermont incorporated wells relocated using this approach and allowed for additional detail on both the map and cross-sections. The increase in accurately located wells allows geologists to interpret information from clusters of wells instead of relying on single well reports.