The chemical data, which reside in the U.S. Geological Survey's National Water Information System (NWIS) (Maddy and others, 1989), are published here in formatted water-quality tables or in flat files (columns of data) to allow flexibility in the use of the data. For the water-quality data at each site, there is a formatted table for browsing the data that can also be printed directly from the Web page. There are also options available to download the raw data in tab delimited format for each site or to download the data collected at all the sites in each activity.

The tab delimited files are ASCII files of tab delimited columns of data for which there is a code definition guide for selected items in each data set (i.e. medium code = 6). A blank in a constituent column indicates that the constituent was not analyzed for in the sample or that a concentration could not be determined.