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U.S. GEOLOGICAL SURVEY
Open-File Report 2007–1390

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Introduction

Alaska’s water-resource managers are charged to adequately and cost-effectively characterize the status, trends, and needs of the State’s waters. Because it is financially impossible to monitor all lakes and streams in Alaska, the use of randomized designs, such as AKMAP, will be critical for developing information to support management decisions and reporting needs. In 2004, a cooperative project between ADEC and USGS began a pilot AKMAP project to evaluate the USEPA Environmental Monitoring and Assessment Program (EMAP) wadeable stream study protocols on the Tanana River Basin in Alaska. The Tanana River originates in the Yukon Territory, Canada, flows west, and discharges into the Yukon River and Tanana, Alaska (fig. 1). The basin covers more than 116,000 km² and lies south of the Yukon River where discontinuous permafrost has been thawing in recent decades (Jorgenson and others, 2001). Population growth within the basin and along the Tanana River combined with such large-scale environmental changes as a result of warming climate may have important consequences for the hydrology and water quality of the Tanana River and its tributaries.

The proposed study area is useful because a wide variety of land uses occur within the unit. These activities include forestry, agriculture, mining, recreation, subsistence, national defense, supporting urban, suburban, and village communities. Federal and State conservation units such as national parks and wildlife refuges also are located in the Tanana River basin.

The USGS assisted ADEC in selecting the sampling sites following USEPA guidelines. Once the sites were selected, the USGS determined basin characteristics such as area and annual precipitation for each site using Geographical Information System (GIS) methods. USGS, ADEC and University of Alaska, Anchorage (UAA) Environmental Research Institute (ENRI) personnel collected water samples from 2004 to 2006. In conjunction with the USGS Yukon River National Stream-Quality Accounting Network program, the sampling parties also obtained water samples at each site for analysis by the USGS NRP. In-situ pH, specific conductance, water temperature and dissolved-oxygen concentrations were measured and samples were analyzed for major ions, dissolved organic carbon, and oxygen isotopes. This report contains the field water-quality constituents and water-quality data analyzed by the USGS for water years 2004–06. The sample-collection methods and the laboratory analytical methods also are described. The AKMAP wadeable stream pilot project also collected separate water-quality parameters, such as nutrients, site flow measurements, stream invertebrate and periphyton collections, and physical habitat data.

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