GEOSPATIAL DATA FOR ASSESSMENT OF KARST AQUIFERS IN NEW YORK STATE

The State of New York has identified a need for improved understanding and awareness of karst aquifer contamination susceptibility, particularly in areas of heavy agricultural use. Karst aquifers in New York are generally poorly described, and thus difficult to properly manage and protect. To improve knowledge of these aquifer systems and aid in assessment and management of these groundwater resources, a series of new and updated geospatial data products were developed to provide hydrogeologic data to State and local agencies. In the first phase, efforts were focused on the belt of Silurian and Devonian carbonate and evaporite units that span New York State from Albany in the east to Buffalo in the west. A well database consisting of 15,904 domestic water wells, monitoring wells, construction boreholes, and oil and gas wells derived from State and U.S. Geological Survey databases was constructed across parts of 19 counties, spanning approximately 280 miles (450 kilometers) from east to west and 34 miles (55 kilometers) from north to south (approximately 7,000 square miles or 11,260 square kilometers). Bedrock lithology information from well logs was used to refine previously published bedrock geologic maps for the units of interest. Surficial geology was refined using a combination of published maps and surface topography. Bedrock and groundwater elevation maps and contours were created by interpolating depth information from the well logs and subtracting the resulting rasters from land-surface elevation. Geostatistical interpolation methods were compared using a Jupyter notebook, and the methods which produced the lowest root-mean-squared error were chosen for the final interpolations of bedrock and groundwater depth. Finally, surface topography derived from high resolution lidar (1 meter grid) was used to construct a database of closed depressions, with depths of 10 and 30 centimeters, across the entire area of interest. These data products provide a new inventory of hydrogeologic parameters that can be used as a basis for resource assessment and protection and future karst studies. This approach is currently being applied to other karst regions of New York State to provide an up-to-date, statewide database of karst aquifers.