How do the individual NAWQA study areas fit in a national assessment?
Each of the studies in the 51 Study Units followed a nationally consistent approach and used uniform methods of sampling and analysis. Each Study-Unit assessment resulted in a USGS general publication written for a broad audience interested in resource management, regulations, and policy. In each, the occurrence and distribution of nutrients, along with pesticides, VOCs, metals, dissolved solids, and radon are described, as well as the condition of aquatic habitat and fish, insect, and algal communities. The assessments relate contaminant sources, land and chemical use, hydrology, and other human and natural factors to water quality and the status of aquatic communities. Results are placed in the context of human and aquatic water-quality benchmarks, which help to determine what these conditions may imply for the protection and safety of drinking water, for the health of aquatic ecosystems and for resource management. The consistent, multi-scale approach provides an understanding of ho
