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Hydrologic Networks and Analysis Program (HNA)

Welcome to the Hydrologic Network and Analysis Program (HNA)

The Hydrologic Networks and Analysis (HNA) supports a number of key activities in the Water Mission Area, and is a basic science support program. The Federal funds appropriated through the HNA program support four distinct water-quality networks, information delivery for the USGS water resources programs, and basic research.

HNA funds 200 scientists and technicians throughout the Water Mission Area and across the U.S. Funding supports basic water-quality networks, database maintenance and development, internet applications, quality-assurance and quality-control activities, and basic research. Through HNA, the USGS provides technical support to the Bureau of Reclamation and the National Park Service through the Water-Quality Partnership.


HNA supports long-term national networks for the collection of data on water quality and atmospheric deposition, including the National Stream Quality Accounting Network (NASQAN), the Hydrologic Benchmark Network (HBN), and the National Atmospheric Deposition Program (NADP). This program component also includes activities related to the new National Water Quality Monitoring Network, a multi-agency effort conducted under the auspices of the President's Ocean Action Plan.

The NASQAN program samples 33 streams (10 of these are in conjunction with the NAWQA or Coop Programs). Of these, 13 are coastal rivers and 20 are inland stations on the Mississippi and Atchafalaya River Basins. The 12 coastal sites in the conterminous US account for 80 percent of the total discharge. The 13th coastal site is the Yukon in Alaska. NASQAN data are used to estimate annual loads of nitrogen and phosphorus to the Gulf of Mexico. National Oceanic and Atmospheric Administration (NOAA) uses this information to make annual forecasts of the hypoxia zone in the Gulf of Mexico. In collaboration with other Water Mission Area programs NAWQA and NSIP, HNA supports water quality monitoring at 15 undisturbed streams and rivers to determine the influence of atmospheric deposition and the Clean Air Act on stream ecosystems. Through HNA, USGS monitors 76 sites in the 250-site NADP National Trends Network (NTN) and 6 sites in the NADP Mercury Deposition Network. The NTN is the only network providing long-term records of precipitation chemistry in the U.S., and data from the NTN are used by EPA and others in the regulation of atmospheric emissions.

Studies of the effect of climate change on water-resources in the U.S. are supported through this program. For example, research on the potential effects of specific levels of atmospheric warming on streamflow in the Colorado River basin were evaluated using a water-balance model, and the results are analyzed within the context of a multi-century tree-ring reconstruction (1490-1998) of streamflow for the basin. The results indicate that if future warming occurs in the basin and is not accompanied by increased precipitation, then the basin is likely to experience periods of water supply shortages more severe than those inferred from the long-term historical tree-ring reconstruction there is an increasing the likelihood that the water allocation requirements of the Colorado River Compact would not be met. Models developed through HNA also suggest that a 1°-3°C warming could have major negative effects on water availability in the upper Yellowstone. These results also indicate that twentieth-century observations paint an incomplete and potentially overly optimistic picture of regional water supplies.

The HNA program provides national technical support for geographically distributed USGS water-resources studies, including quality control to ensure the technical excellence of water resources programs. Technical support also provides a structured way of transferring new technology to USGS investigative and data activities that are primarily conducted in the USGS Water Science Centers located in each State, and a formal way of establishing priorities for water-resources research by the USGS (Klamath Basin Studies and Priority Ecosystems Science).

The HNA program supports delivery of results and water information beyond the immediate needs of funding agencies or programs (the USGS funds the delivery of basic hydrologic data directly as a part of the overall cost of the data collection). This activity has two products: publications and the computer-based National Water Information System (NWIS). This component of the HNA program also supports activities of the Advisory Committee on Water Information (ACWI), a Presidential Federal Advisory Committee, and its subcommittees. The goal of this program component is to maintain and enhance USGS data delivery systems to process and disseminate water data and study results.

Key Stakeholders:

Because of the program's wide range of activities, the data and analytical information provided through Hydrologic Networks and Analysis are used by a variety of stakeholders, including —

  • Other Interior bureaus (National Park Service water quality partnership),
  • EPA and USDA (baseline water-quality information through HNA networks),
  • Department of Commerce (real-time flood level information provided through the National Water Information System, which HNA supports),
  • State and local governments (water-quality and flood level information),
  • Academia,
  • Consulting and advocacy organizations,
  • Industry, and
  • Private citizens.

Contact: Earl Greene (eagreene@usgs.gov; 443-498-5505)

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