Process Description:
The WHPA delineations were; until 2011; exclusively created using the methods outlined in "Guidelines for Delineation of Well Head Protection Areas in New Jersey" available as a download at <http://www.state.nj.us/dep/njgs/whpaguide.pdf>. Coordinate files delineating each WHPA boundary were generated using a custom MS-DOS program on-file at the offices of the N.J. Geological Survey. The resultant coordinate files are formatted as comma delineated ASCII-text and contain line coordinate pairs for each of the groundwater time of travel tiers. Up until 2011, coverages were generated with the Arc/INFO Generate command having both arc (line) and polygon attributes for the three Time of Travel (TOT) tiers. County and statewide WHPA coverages were created using the Arc/INFO Union command. The coverages were then converted to shapefiles. After 2015, the existing individual WHPA coverages were converted to ArcGIS geodatabase features into county feature classed. These features were combined into county-based and then a statwide WHPA feature using the ArcGIS Merge command. New WHPA geodatabase features are generated using an Arc/GIS Python-based, feature-creation script. Each new WHPA is merged into the existing statewide feature. WHPA delineations are considered to have an accuracy of plus or minus 40 feet in any direction from the mapped location. WHPA delineations for wells completed in the glacial sand and gravel aquifer were clipped to a custom hydrologic boundary. Sand and gravel aquifers occur where deposits are more than 50 feet thick. The hydrologic boundary is generated as a 2000 foot buffer around the polygon representing the contact of the sand and gravel aquifer for those areas where the aquifer is less than 50 feet thick. This distance was selected based on an average distance between the 50 and 100 foot thickness contours of the sand and gravel aquifer. The average inter contour distance was doubled to provide a conservative estimate of the thickness variation. Therefore, any portion of the WHPA delineation that lies beyond this extent is clipped. For the confined wells a fifty foot buffer was used to delineate the well head protection area. Note: Since 2009, the permit number naming system has changed in the Bureau of Water Allocation winthin the New Jersey Department of Environmental Protection. Because of this, a new alias number is given as the WELLID for each individual well head protection area delineated and is not directly related to the permit number for the well. A web page with the information for new wells can be found at the following link: http://www.nj.gov/dep/njgs/geodata/whpafilelist.htm. After 2015 a new ALIAS field allows each WHP to be joined to its associated PCWS well. Due to security consideration, the PCWS well features are not available for direct download but must be requested from the NJDEP.