Georgia Water Science Center

USGS Open-File Report 97-48


This report is available online in pdf format (3 MB): USGS OFR 97-48 (Opens the PDF file in a new window. )

David J. Wangsness

U.S. Geological Survey Open-File Report 97-48, 29 pages (Published 1997)


Much of the water-quality monitoring conducted in the United States is designed to comply with Federal and State laws mandated primarily by the Clean Water Act of 1987 and the Safe Drinking Water Act of 1986. For example, the State of Wisconsin estimates that more than 98 percent of it’s monitoring program is compliance monitoring, and Washington State estimates that 80 to 90 percent of its monitoring program is compliance monitoring. A small percentage of the water-quality data in the United States has been collected as a part of ambient monitoring programs or river-basin assessments. Monitoring programs generally focus on rivers upstream and downstream of point-source discharges and at water-supply intakes. Few data are available for aquifer systems and chemical analyses are often limited to those constituents required by law. In most cases, the majority of the available chemical and streamflow data have provided the information necessary to meet the objectives of the compliance monitoring programs; however, do not necessarily provide the information required for basinwide assessments of water quality at the local, regional, or national scale.

During the period 1972–86, an estimated $541 billion was expended for water-pollution abatement in the United States; and in 1986, the U.S. Congress asked if the Nation’s water quality was improving as a result of those expenditures. For various reasons, this basic question could not be answered satisfactorily using only existing ambient- and compliance monitoring data. Therefore, the U.S. Geological Survey (USGS) was requested to design and implement a National Water-Quality Assessment (NAWQA) Program to address the questions related to status and trends in surface- and ground-water quality at national, regional, and local scales. The program was fully implemented in 1991.

An initial task of the NAWQA Program was to locate and evaluate existing data, and use those data to help meet as many of the program goals as possible. In general, these data are stored in computerized data bases or as paper files and are available upon request. The sharing of these data generally is not an issue within and among the various governmental agencies. Far greater issues are standardization, quality assurance, and some assurance that the shared data meet program goals and help to answer the questions being asked.

Because the existing data were not adequate to meet the goals of the NAWQA Program, the USGS has designed and is implementing water-quality monitoring networks within large river basins and major aquifer systems that, when combined with existing programs, will provide the information necessary to meet program goals. Great care has been taken to use standardized study approaches and techniques for data collection, laboratory analyses, and quality assurance so that information is comparable throughout the United States and can be compiled at various scales.

Some of the experiences gained by the USGS during the development of the NAWQA Program may be useful when developing an international data sharing program for the effective management of Danube River basin resources. It is important for participating nations to agree upon ways to share data, but if those data are collected as part of compliance monitoring programs, similar to those in the United States, it can not be assumed that those data alone will provide the information needed to assess the quality of the Danube River or design effective management programs. In addition to agreeing to share data, it is equally important for the participating nations to agree upon mutual goals and a valid design for the assessment program.

It is important to start by identifying questions and issues related to the water quality of a river basin; prioritize those questions and issues; and based on that prioritization, identify and prioritize a list of data and information needs. The next step is to identify and locate sources of existing data; consolidate the data; process, summarize, and evaluate the data; and share the results. This information then could be used to determine which of the priority questions could be answered using existing data, which could not be answered, and what data are necessary to fill information gaps. An assessment program then could be designed to fill the gaps; taking care to standardize approaches, techniques, and data bases; and to use new data in conjunction with existing data to address the priority questions. Standardization is critical throughout the programme so that the combined efforts of all participants will provide the information needed to answer the questions; and thereby, attain the agreed upon goals.

This evaluation is not meant to be a criticism of the available data from compliance-monitoring programs; but rather to point out that those data were collected to meet specific goals and to answer specific, short-term questions, and not for the purpose of meeting the goals of a long-term, river-basin-scale assessment. All data sets can be an important source of information for a water-quality assessment program, but their limitations need to be recognized and evaluated, and often, new data need to be collected to address specific assessment goals.




Purpose and scope

Water-quality legislation

Standards and guidelines

Water-quality monitoring programs

The National Water-Quality Assessment Program

The National Water-Quality Assessment Program design

Planning and study design

Analysis of existing data

Intensive data collection

Surface-water monitoring network

Integrator sites

Indicator sites

Intensive sites

Comparison sites

Synoptic sites

Bed-sediment and tissue surveys

Ground-water monitoring networks

Study-unit survey

Land-use studies

Flow-system studies

Ancillary data

Special studies

Analysis, interpretation, and reports publication

Example of study-unit design for the Apalachicola-Chattahoochee-Flint River basin

Planning and retrospective analysis phases

Intensive data-collection phase

Surface-water design

Integrator sites

Indicator sites

Intensive sites

Comparison sites

Synoptic sites

Bed-sediment and tissue surveys

Ground-water design

Study-unit survey

Land-use studies

Flow-system study

Special studies

Current status of Apalachicola-Chattahoochee-Flint River basin National Water-Quality Assessment study


References cited



This report is available online in pdf format (3 MB): USGS OFR 97-48 (Opens the PDF file in a new window. )
To view the PDF document, you need the Adobe Acrobat® Reader installed on your computer. (A free copy of the Acrobat® Reader may be downloaded from Adobe Systems Incorporated.)

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