The ALMN Project and NAWQA Program


NAWQA Program Overview

[NAWQA Study Units of the United States]      In 1991 the U.S. Geological Survey (USGS) initiated the National Water-Quality Assessment (NAWQA) Program to assess the status and trends in the quality of freshwater streams and aquifers, and to provide a sound understanding of the natural and human factors that affect the quality of these resources. The design is based on balancing the unique assessment requirements of individual hydrologic systems with a nationally consistent design structure that incorporates a multiscale, interdisciplinary approach for ground water and surface water.

The "building blocks" of the NAWQA Program are the individual hydrologic systems -- called study units-- which presently include 59 areas located throughout the Nation. These study units provide the framework for a national and regional water-quality assessment. Together, these areas account for 60-70 percent of the Nation's water use and population served by public water supplies, and cover about one-half of the land area of the Nation. Twenty study-unit investigations were started in 1991, an additional 16 were started in 1994, 15 were started in 1997, and 2 were started in 1999. An additional seven study-unit investigations are planned for the future.

      ALMN Project Overview

[ALMN NAWQA Study Unit Location]       As part of the NAWQA Program, the USGS is evaluating water quality in the Allegheny and Monongahela (ALMN) River Basins. The ALMN Study-Unit Investigation was started in 1994. The ALMN drainage basin is the largest stream system in southwestern Pennsylvania. The Study Unit covers an area of about 19,145 square miles in part or all of 16 counties and four states, including Pennsylvania, Maryland, New York, and West Virginia. The Study Unit is home to more than 3.1 million people who rely on surface and ground-water resources that originate within the basin. In 1990, water withdrawn from aquifers and surface-water bodies in the Study Unit averaged 3 billion gallons per day, most of which was from surface-water sources (McAuley and others, 1997). Additional information on the Study Unit environmental setting is available.

[Gaging Station at S. Branch Plum Creek Intensive Fixed Site]      The quality of the surface water, ground water, and aquatic life in the ALMN Study Unit can be significantly affected by several principal issues, including:

For information on the ALMN Project Study-Unit Design see the Project Overview, for description of each surface water and ground water study component, or see the Summary Table, for an overview of all the study components.

[ALMN NAWQA Project Timetable]      Initial ALMN Project activities included detailed planning during the first year and analysis of existing data during the second year. The suceeding 3 years are for intensive data collection and analysis. The sixth year is for completion of data analysis and reports. These activities will be followed by a period of low-level assessment, mainly intermittent water-quality monitoring, at selected sites. The next cycle of intensive data collection and analysis will follow the low-level assessment period (McAuley and others, 1997). Nationally, about one-third of the study units are in the intensive-study phase at any given time.

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