INTRODUCTION

NAWQA is designed to assess historical, current, and future water-quality conditions in representative river basins and aquifers nationwide. One of the primary objectives of the program is to describe relations between natural factors, human activities, and water-quality conditions and to define those factors that most affect water quality in different parts of the Nation. The linkage of water quality to environmental processes is of fundamental importance to water-resource managers, planners, and policy makers. It provides a strong and unbiased basis for better decisionmaking by those responsible for making decisions that affect our water resources, including the United States Congress, Federal, State, and local agencies, environmental groups, and industry. Information from the NAWQA Program also will be useful for guiding research, monitoring, and regulatory activities in cost effective ways.

PROGRAM DESIGN

The similar design of each investigation and use of standard methods make comparisons among the study unit's results possible. Regional and national assessments can be made. These regional and national assessments, referred to as "National Synthesis," focus on priority national issues, including non-point source pollution, sedimentation, and acidification. Each issue is unique and manifests itself differently among the Nation's diverse geographic, geologic, hydrologic, and climatic settings. The challenge and goal for NAWQA is, therefore to identify the common environmental characteristics associated with the occurrence of key water-quality constituents and to explain their differences throughout the Nation.

PROGRAM IMPLEMENTATION

(15KB GIF). To make the program cost effective and manageable, intensive assessment activities in each of the study units are being conducted on a rotational rather than a continuous basis, with one-third of the study units being studied intensively at any given time For each study unit, 3- to 5-year periods of intensive data collection and analysis will be alternated with 5- to 6-year periods of less intensive study and monitoring.

Locations of the 60 NAWQA study units and their proposed implementation dates (26K GIF)

Coinciding with the study-unit investigations are the national synthesis assessments. The large geographic extent and large variability in environmental factors throughout the Nation, and limited resources make it necessary to focus on a limited set of high priority water-quality issues. Generally, two to four national synthesis topics will be studied at a given time. Two issues of national priority--the occurrence of nutrients and pesticides in rivers and ground water--were selected as the first issues investigated by national synthesis. These topics were ranked among the highest in importance because of widespread environmental and public health concerns and because information necessary for a national assessment of these contaminants was incomplete.

The next topic for national synthesis is the occurrence and distribution of volatile organic compounds (VOCs). Many VOCs are toxic and are a major focus of a number of Federal regulations related to water quality. Major work elements planned for the study of VOCs in 1994 and 1995 are to (1) identify regulated and non-regulated VOCs; (2) determine the amounts of VOCs released to water, land, and air, and (3) evaluate strategies to characterize the use and releases of VOCs to the environment, including ground water.

The first two years of both study-unit investigations and national synthesis studies involve compilation and analysis of existing information. In addition to USGS data, information and methods developed by other Federal agencies, as well as by State and local agencies, universities, and volunteer organizations are reviewed and integrated as appropriate. This preliminary information on water-quality conditions, trends, and functions forms the basis of a three-year period of intensive data collection and analysis to fill identified gaps in subsequent years.

Perennial data collection and sequential assessments in the study units and regional and national synthesis are key attributes of the program, not only to define changes and trends, but also to build an evolving understanding of water quality in each of the study units and across the Nation. This understanding will be achieved through careful analysis and interpretation of long-term data sets on the physical, chemical, and biological characteristics of the water resource. The data sets will be related to carefully compiled information on hydrology and geology and changes in land-use activities and management practices. The long-term commitment of the NAWQA Program to water-quality monitoring at local, regional, and national scales is designed to answer critical questions about the status and trends in the quality of our Nation's water.

EARLY FINDINGS

Highlights of NAWQA Study Unit Findings

• Hudson River Basin
  
• Delmarva Peninsula
  
• Western Lake Michigan drainage
  
• Red River of the North
  
• Trinity River Basin
  
• Lower Kansas River Basin
  
• Rio Grande Valley
  
• Upper Snake River Basin
  
• Yakima River Basin
  
• Nevada Basin and Range
  

Selected early results from the National Synthesis on Pesticides and Nitrates include the following:

• A review of existing information on pesticides in the atmosphere showed that pesticides have been detected in most samples analyzed throughout the Nation. Pesticides were ubiquitous and were generally detected wherever they were sought. The degree of use and environmental persistence explain the dominant patterns in frequency of detection. The review revealed that no consistent, long-term studies at a national scale have been done.
  
• A statistical analysis of the occurrence of nitrate in streams at about 150 sites in 10 states in the Midwest, showed there was a relation between the concentration of nitrate and each of the following: the amount of precipitation, rate of streamflow, the acreage of the basin planted in corn, the acreage planted in soybeans, cattle density, and population density. These findings help State and local managers to focus scarce monitoring resources to the most critical areas.
  
• Estimates of point- and nonpoint-source nitrogen loadings were made for about 90 watersheds throughout the United States. The relative proportions of input to streams vary as a function of climate, hydrology, land use, population, and physiography. A large percentage of point-source loads occur near cities. Nonpoint loading varies widely, and is strongly influenced by precipitation and runoff. However, no single nonpoint-nitrogen source is dominant everywhere. Information derived from NAWQA study units will aid in the development of methods to reduce point- and nonpoint-source nitrogen loading.
  
• Effects of agricultural activities on ground-water quality was studied in five regions from New York to Nebraska. The quality of water in surficial, unconsolidated aquifers was affected by the geology and soils, land-management practices, fertilizer use, and the amount of irrigation. Concentrations of nitrate were greatest in areas that are heavily irrigated or areas that have well-drained soils or sediments.
  

COMMUNICATION AND COORDINATION

More information on this and related studies.

U.S. Department of the Interior, U.S. Geological Survey Maintainer: Kerie Hitt (kjhitt@usgs.gov) Last update: 11:58:21 Wed 26 Dec 2007 Privacy Statement || Disclaimer || Accessibility URL: http://water.usgs.gov/nawqa/NAWQA.OFR94-70.html