Abstract

Methods for Water-quality Sampling Site Selection and Area Characterization
Track: Water Resources
Authors: Curtis Price, Naomi Nakagaki

Water-quality assessments typically require (a) development of geospatial datasets used for sampling site selection, and (b) statistical characterization of areas defined by aquifers, watersheds, and proximity to sampling sites. The U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program has developed standardized geographic information system (GIS) methods to perform spatial overlays, calculate land-use percentages, estimate area-weighted statistics, and 'thin' point datasets to reduce autocorrelation effects. Software scripts have been used to implement these methods consistently; these scripts have been updated over time as GIS technology has changed. A set of software tools compatible with ArcGIS Desktop software is publicly available to allow researchers outside of USGS to apply these standardized GIS methods to their own water-quality studies. The tools can be accessed at http://pubs.usgs.gov/of/2010/1268/.