punctuated rotational sampling design, and assessment using established methods (Box 2-1).

Shortly after the NRC’s Water Science and Technology Board (WSTB) endorsed the original concept of the National Water-Quality Assessment (NAWQA) program (Chapter 1), it convened a colloquium in 1986 to articulate the necessary elements for a national water-quality assessment program (NRC, 1987). Colloquium participants endorsed the program concept and also raised new issues for consideration such as whether and how to interface with state regulators, which contaminants would be selected for monitoring, and the need to explore surface water and groundwater interactions. For example, the original study unit concept consisted of 123 separate surface water and groundwater units: 69 surface water-dominated and

BOX 2-1

The Original Vision for the NAWQA Program

The USGS vision for NAWQA included selecting study units, or hydrologically meaningful pieces of geography (Winter, 2001), in which to monitor water quality. The study units were building blocks for multiple scales of water quality investigation; they served not only as the base level but also as tools for “scaling up” to the bigger, national picture. Consistency between study units would allow the program to make comparable statements about the nation’s water quality.

Data collection and data analysis for the water quality assessment in each study unit were to be done by a team working together in an integrated group. This team of scientists was to make measurements, understand what these measurements meant, and make a statement about water quality in a given study unit. It was thought that sampling and assessment should follow a punctuated, rotational system of study with intense data collection for approximately 3 years followed by a period of analysis and publication, a time of minimal monitoring, and a return to the area to repeat the cycle.

NAWQA was envisioned to be a network for data collection defined by geology, hydrology, and land use, rather than a grid or a random sampling strategy. In this way, NAWQA could capture snapshots of both the entire system and “indicator” sites. The design had a strong prejudice toward collecting data in places where USGS had high-quality streamflow data records, in the belief that surface water-quality data are meaningless without considering flow and long-term history. Finally, use of known tools and understanding of processes to monitor the nation’s water quality were critical components of the original vision. NAWQA would not deploy untested methods and approaches for analyzing water quality unless on a limited scale. Rather, research and development of methods in other USGS programs would feed the program’s activities and assist the program in achieving the goal of assessing the nation’s water quality.

SOURCE: R. M. Hirsch, personal communication, May 13, 2009.

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