• White Paper

SDWIS intake indexing and time of travel catchment generation: A whitepaper with comparisons to Special Office of Pesticide Program intake location materials

Citation

Rineer, J. I., Bergenroth, B., & Cooter, W. S. (2007). SDWIS intake indexing and time of travel catchment generation: A whitepaper with comparisons to Special Office of Pesticide Program intake location materials. Research Triangle Park, NC: RTI International.

Abstract

This document describes the process and algorithms developed to produce a baseline of NHDPlus-indexed surface water intake information for use in the OGWDW DWMA mapping application using off-NHD latitude/longitude coordinates contained in the Safe Drinking Water Information System (SDWIS) system for 2006, 3rd quarter. An additional baseline 24 hour upstream time of travel NHDPlus catchment dataset was also created and will be described. A second set of intake latitude/longitude coordinates was made available by the EPA office of pesticide programs (OPP) reflecting enhancements to the intake latitude/longitude coordinates provided by the US Geological Survey (USGS). Instead of simply comparing the proximities of the “raw” off-NHD latitudes and longitudes for surface intake-relevant facilities with matching IDs, the comparisons discussed in this whitepaper focus on the results of placing the facilities as point events on the NHDPlus reaches. Proximity tests for these on-NHD locations are felt to provide a good way to identify cases where adjustments to the values of the original off-NHD latitude/longitude coordinates lead to appreciable difference in georeferencing the facilities to the NHD. This study summarizes results of running both set of off-NHD coordinates through the same NHDPlus indexing process. Summaries and comparisons of the two end products, the indexed locations and the catchment navigation, are provided.