Potomac River at Chain Bridge, at Washington, D.C.

Data from Selected U.S. Geological Survey National Stream Water-Quality Monitoring Networks (WQN)

By Richard B. Alexander, James R. Slack, Amy S. Ludtke, Kathleen K. Fitzgerald, and Terry L. Schertz

USGS Digital Data Series DDS-37

During the past 30 years, the U.S. Geological Survey (USGS) has operated two national stream water-quality networks (see map below), the Hydrologic Benchmark Network (HBN) and the National Stream Quality Accounting Network (NASQAN). In these networks, the USGS systematically monitored streams in watersheds throughout the United States to provide national and regional descriptions of stream water-quality conditions and trends and to improve our understanding of the effects of the natural environment and human activities on water quality. The HBN, consisting of 63 relatively small, minimally-disturbed watersheds, provides data for investigating naturally-induced changes in streamflow and water quality and the effects of airborne substances on water quality. NASQAN, consisting of 618 larger, more culturally-influenced watersheds, provides information for tracking water-quality conditions in major U.S. rivers and streams. The watersheds in both networks include a diverse set of climatic, physiographic, and cultural characteristics. Data from the networks have been used to describe geographic variations in water-quality concentrations, quantify water-quality trends, estimate rates of chemical flux from watersheds, and investigate relations of water quality to the natural environment and anthropogenic contaminant sources.

The networks included 63 HBN stations from 1962-95 and 618 NASQAN stations from 1973-95. Stations located outside of the conterminous United States for NASQAN included 13 in Alaska, 8 in Hawaii, 6 in Puerto Rico, and 1 in Guam; HBN stations included 1 each in Alaska and Hawaii.


Much of the historical water-quality and streamflow data collected by the NASQAN and HBN and supporting documentation including quality-assurance information have been assembled in an easy-to-use format on two CD-ROMs. These data are collectively referred to as Water-Quality Networks (WQN).

The data retrieval tools and ancillary information provided on the CD-ROMs allow for the efficient and proper use of WQN data. The CD-ROMs are designed to allow users to efficiently browse text files and retrieve data for subsequent use in user-supplied software including spreadsheet, statistical analysis, or geographic information systems. The data may be extracted from one of the CD-ROMs (the "DOS disc") using the supplied DOS-based software, and output in a variety of formats. This software allows the user to search, retrieve, and output data according to user-specified criteria. Alternatively, the ASCII form of the WQN data may be accessed on a second CD-ROM (the "ASCII disc") from user-supplied software including Web browser, spreadsheet, or word processor.

Access to the contents of the "ASCII disc" is provided in these Web pages.

Contents of the CD-ROM Data

The WQN data base contains water-quality and streamflow data collected at 679 NASQAN and HBN stations in the United States. The water-quality data include a set of 63 physical, chemical, and biological properties analyzed during more than 60,000 stream visits using relatively consistent sampling and analytical methods. The water-quality data reflect sampling over a wide range of streamflow conditions.

Supporting information identifies and describes the water-quality and streamflow stations, water-quality constituents, and the methods, remarks, laboratories, sample collection agencies, and the laboratory measurement accuracy associated with the WQN data.

The WQN data include the following:

Open-File Report 96-337

Water Quality and Streamflow Data
Blind Sample Program (BSP) Data

Quality-Assurance Information


Additional Documentation

More Information about WQN.
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Last modified: Fri Mar 2 08:12:13 EST 2001
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