How does this report relate to USGS water quality reports/programs?
The WSA and the USGS NAWQA program differ in scope and design. The USGS NAWQA studies are based on a sampling design that targets specific watersheds that are influenced primarily by a single dominant land use (e.g., agricultural or urban). The NAWQA sampling design was selected to support analysis of relationships between water quality and land use, and is used by analysts to develop models that predict water quality. USGS also summarizes the monitoring results by describing the number of sites where chemicals are detected and at what level. The WSA, on the other hand, does not consider land use in its site selection, has a random sample design (meaning that every site in the target population of all perennial 1st through 5th order streams had an equal chance of being selected for sampling) so results are not limited to the sampled sites, but rather, represent the entire population of perennial, wadeable streams. Both of these designs provide important data and tools to support water
