Data from Selected U.S. Geological Survey National Stream Water-Quality Monitoring Networks (WQN) on CD-ROM
Open-File Report 96-337

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

Summary

Historical water-quality and streamflow data and supporting documentation and quality-assurance information for the U.S. Geological Survey's National Stream Quality Accounting Network (NASQAN) and the Hydrological Benchmark Network (HBN) have been assembled in an easy-to-use form on two CD-ROMs. The data from these networks include measurements for a set of 63 physical, chemical, and biological water properties for a time period spanning the past 30 years. Network data describe stream water-quality conditions in 679 watersheds with diverse climatic and cultural characteristics, ranging from the relatively small, minimally disturbed watersheds in the HBN to the larger, more culturally- influenced drainage basins of NASQAN. Expenditures for these two national networks have totaled approximately $95 million through 1995. Data collection has occurred during a period of significant changes in terrestrial and atmospheric sources of water pollutants in the United States stemming, in part, from the enactment of major federal legislation in the 1960's and 1970's. The national networks have provided some of the best available monitoring data for investigating the influences of these pollutant sources on national and regional water quality. Numerous studies have also used data from the national networks to investigate state and local stream water quality. Overall, national network data have been frequently used at widely-varying geographic scales to quantify trends in water quality, estimate rates of chemical flux from watersheds, and investigate the relations of water quality to the natural environment and human activities.

The CD-ROMs provide the necessary information and data- retrieval tools to allow the national network data to be accurately and efficiently used. In addition to the stream water-quality monitoring data, we include ancillary information on the objectives and characteristics of the network stations and water-quality data, historical records of network operations and sample collection and analytical methods, a bibliography of scientific investigations using national network data and other publications relevant to the networks, water reference sample data for estimating laboratory measurement bias and variability, and discussions of statistical methods for using reference sample data to evaluate the accuracy of network water-quality data.

The data structure of the CD-ROMs is designed to allow users to efficiently input the water-quality data to user-supplied software packages including statistical analysis, modeling, or geographic information systems. On one disc, all data are stored in ASCII form accessible from any computer system with a CD-ROM driver. The data can also be accessed using DOS-based retrieval software supplied on a second disc. Logical data queries of the water-quality data can be made for constituent concentrations, sample-collection date, river name, station name, county state, and hydrologic unit identifiers, and 1990 population and 1987 land-cover characteristics for station watersheds. User-selected data can be output in a variety of formats for subsequent use in other software packages.


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Last modified: Thu Jan 16 15:00:27 EST 1997