Database used for the evaluation of data used to identify groundwater sources under the direct influence of surface water in Pennsylvania

The U.S. Geological Survey (USGS), in cooperation with the Pennsylvania Department of Environmental Protection (PADEP), conducted an evaluation of data used by the PADEP to identify groundwater sources under the direct influence of surface water (GUDI) in Pennsylvania (Gross and others, 2022). The data used in this evaluation and the processes used to compile them from multiple sources are described and provided herein. Data were compiled primarily but not exclusively from PADEP resources, including (1) source-information for public water-supply systems and Microscopic Particulate Analysis (MPA) results for public water-supply system groundwater sources from the agency’s Pennsylvania Drinking Water Information System (PADWIS) database (Pennsylvania Department of Environmental Protection, 2016), and (2) results associated with MPA testing from the PADEP Bureau of Laboratories (BOL) files and water-quality analyses obtained from the PADEP BOL, Sample Information System (Pennsylvania Department of Environmental Protection, written commun., various dates). Information compiled from sources other than the PADEP includes anthropogenic (land cover and PADEP region) and naturogenic (geologic and physiographic, hydrologic, soil characterization, and topographic) spatial data. 
Quality control (QC) procedures were applied to the PADWIS database to verify spatial coordinates, verify collection type information, exclude sources not designated as wells, and verify or remove values that were either obvious errors or populated as zero rather than as “no data.” The QC process reduced the original PADWIS dataset to 12,147 public water-supply system wells (hereafter referred to as the PADWIS database). 
An initial subset of the PADWIS database, termed the PADWIS database subset, was created to include 4,018 public water-supply system community wells that have undergone the Surface Water Identification Protocol (SWIP), a protocol used by the PADEP to classify sources as GUDI or non-GUDI (Gross and others, 2022).
A second subset of the PADWIS database, termed the MPA database subset, represents MPA results for 631 community and noncommunity wells and includes water-quality data (alkalinity, chloride, Escherichia coli, fecal coliform, nitrate, pH, sodium, specific conductance, sulfate, total coliform, total dissolved solids, total residue, and turbidity) associated with groundwater-quality samples typically collected concurrently with the MPA sample.
The PADWIS database and two subsets (PADWIS database subset and MPA database subset) are compiled in a single data table (DR_2022_Table.xlsx), with the two subsets differentiated using attributes that are defined in the associated metadata table (DR_2022_Metadata_Table_Variables.xlsx). This metadata file (DR_2022_Metadata.xml) describes data resources, data compilation, and QC procedures in greater detail.

Tags: geoscientificinformation, groundwater, pennsylvania, public-water-supply-system, united-states, usgs-601c6228d34e94a4b9fc2855, water-quality
Organization: Department of the Interior