Process Description:
The WHPA delineations for public non-community water supply wells were generated from a Microsoft Access database created with data from the NJDEP Bureau of Safe Drinking Water and the New Jersey Geological Survey. The database was constructed with all of the available well construction information, depths and pumping rates available for the wells. A statistical analysis was done for each county by NJGS to determine the median values for the depth and pumping rate. These values were assigned to those wells for which the depth and pumping rate were unknown. In addition, the porosity was determined by overlaying the Microsoft Access database of well points after being converted into an ESRI point shapefile onto a surficial geologic map. Those wells in rock aquifers were assigned a value of 0.02 for the porosity and those in unconsolidated aquifer were assigned a value of 0.25. The CFR's for 2, 5 and 12 years were then calculated using the equations: ((pumping rate * time) / (porosity * 3.1415 * depth))^0.5 (([Q]*192.5*730)/([porosity]*3.1415*[depth]))^0.5 2 year CFR (([Q]*192.5*1825)/([porosity]*3.1415*[depth]))^0.5 5 year CFR (([Q]*192.5*4380)/([porosity]*3.1415*[depth]))^0.5 12 year CFR An ASCII text file was then created from this database. The text file consisted of the Bureau of Safe Drinking Water ID number, location, tier 1 cfr, tier 2 cfr and tier 3 cfr. This file was processed using a BASIC program (Noncom.exe) which created the file format needed for importing the data into ARC/INFO. In ARC/INFO the GENERATE command was used to create the delineations. The noncom.exe program was developed by NJGS for creating the PNCWS delineations. Each WHPA coverage was built as both a line and a polyon coverage having both arc and polygon attributes for the three Time of Travel (TOT) tiers. The public non-community water supply well head protection areas state coverage (njcnwhpa) and the 20 county coverages were processed using the UNION command in ARC/INFO to create the state and county coverages from the individual coverages. This statewide shapefile ncwhpa.shp was created from the statewide coverage originally made for this data. The available construction and pumping information used to create these WHPA delineations are available in the associated PNCWS point shapefile available by request from the State Geologist, N. J. Geological Survey, Box 427, Trenton, NJ 08625