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Show What kind of water- quality information does the NAWQA Program provide? Lf.., Water- quality assessments by a single program cannot address all of the Nation's water- resources needs and issues. Therefore, il is necessary to define the context within which NAWQA information is most useful. • Total resource assessment- NAWQA assessments are long- term and interdisciplinary, and include information on water chemistry, hydrology, land use. stream habitat, and aquatic life. Assessments are not limited to a specific geographic area or water- resource problem at a specific time. Therefore, the findings describe the general health of the total water resource, as well as emerging water issues, thereby helping managers and decision makers to set priorities. . /' "•[•-•-.:-::.:.- y}::. y^ yy '^ ;';/.;•'••"•;•' '' V': •': V':'?'-:'•;'^:-:- v:"^-/:";'-":''; V-:;''" \: ? • Source- water characterization- Assessments focus on the quality of the available, untreated resource and thereby complement ( rather than duplicate) Federal. Stale, and local programs that monitor drinking water. Findings are compared to drinking- water standards and health advisories as a way to characterize the resource. • Compounds studied- Assessments focus on chemical compounds that have well- established methods of investigation. It is not financially or technically feasible to assess all the contaminants in our Nation's waters. In general, the NAWQA Program investigates Ihose pesticides, nutrients, volatile organic compounds, and metals that have been or are currently used commonly in agricultural and urban areas across the Nation. A complete lisl of compounds studied is on the NAWQA Web site al http://\\ iiter. usgt>. gov/ n( twciti. • Detection relative to risk- Compounds arc measured al very low concentrations, often 10 to 100 times lower than Federal or Stale standards and health advisories. Detection of compounds, therefore, does not necessarily translate to risks to human health or aquatic life. However, these analyses are useful for identifying and evaluating emerging issues, as well as for tracking contaminant levels over lime. • Multiple scales- Assessments are guided by a nationally consistent study design and uniform methods of sampling and analysis. Findings thereby pertain not only to water quality of a particular stream or aquifer, but also contribute to the larger picture of how and why water quality varies regionally and nationally. This consistent, multiscale approach helps to determine if a water- quality issue is isolated or pervasive. It also allows direct comparisons of how human activities and natural processes affect water quality in the Nation's diverse environmental settings. |