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INTRODUCTION This report briefly describes and presents geochemical and biogeochemical data for a cooperative study in the Fortymile Mining District, east central Alaska. This study is being funded by the U.S. Geological Survey (USGS) Mineral Resources Program through Fiscal Year 2001. Cooperative funds are being provided from various State of Alaska sources through the Alaska Department of Natural Resources. Results for the first field season completed in June 1997 are presented in Crock and others (1999). The study's second field season was completed in June 1998 and the results of the sample analyses for this phase of the study are presented here. Primary objectives of this study are: * Determine the regional...
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The locations of approximately 26,000 current and historical U.S. Geological Survey (USGS) surface-water monitoring gaging stations have been indexed to the NHDPlus Version 2.1 stream network. Part of the USGS National Water Information System (NWIS), these gaging stations measure water flow and water levels in streams and lakes. The NHDPlus V2 stream network locations for these gaging stations differ from stations' latitude/longitude provided in NWIS. The NWIS coordinates are frequently not coincidenet with the NHDPlus stream network.
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Streams across the world are highly fragmented due to the presence of in-stream barriers (e.g., dams and stream-road crossings), many of which restrict or block fish passage. Retrofitting or replacing these structures is a high priority for restoring habitat connectivity for native fishes and other aquatic organisms in the Pacific Northwest. The task of restoring habitat connectivity for problematic stream-road crossings is daunting given the many thousands of barriers that are present and the massive financial investments required. Further, the potential risks to road infrastructure from flooding, debris flows, and climate change will need to be addressed to ensure the best allocation of resources. In this study,...
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The Yukon River Basin, which encompasses 330,000 square miles in northwestern Canada and central Alaska (Fig. 1), is one of the largest and most diverse ecosystems in North America. The Yukon River is also fundamental to the ecosystems of the eastern Bering Sea and Chukchi Sea, providing most of the freshwater runoff, sediments, and dissolved solutes. Despite its remoteness and perceived invulnerability, the Yukon River Basin is changing. For example, records of air temperature during 1961- 1990 indicate a warming trend of about 0.75 °C per decade at latitudes where the Yukon River is located. Increases in temperature will have wide-ranging effects on permafrost distribution, glacial runoff and the movement of carbon...
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The Yukon River, located in northwestern Canada and central Alaska, drains an area of more than 330,000 square miles, making it the fourth largest drainage basin in North America. Approximately 126,000 people live in this basin and 10 percent of these people maintain a subsistence lifestyle, depending on the basin's fish and game resources. Twenty ecoregions compose the Yukon River Basin, which indicates the large diversity of natural features of the watershed, such as climate, soils, permafrost, and geology. Although the annual mean discharge of the Yukon River near its mouth is more than 200,000 cubic feet per second, most of the flow occurs in the summer months from snowmelt, rainfall, and glacial melt. Eight...
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Existing stream temperature data will be compiled from numerous federal, state, tribal, and private sources to develop an integrated regional database. Spatial statistical models for river networks will be applied to these data to develop an accurate model that predicts stream temperature for all fish-bearing streams in the US portion of the NPLCC. Differences between model outputs for historic and future climate scenarios will be used to assess spatial variation in the vulnerability of sensitive fish species across the NPLCC.
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"Descriptions of the [109] mineral occurrences shown on the accompanying figure follow. See U.S. Geological Survey (1996) for a description of the information content of each field in the records. The data presented here are maintained as part of a statewide database on mines, prospects and mineral occurrences throughout Alaska." This and related reports are accessible through the USGS World Wide Web site http://ardf.wr.usgs.gov. Comments or information regarding corrections or missing data, or requests for digital retrievals should be directed to: Frederic Wilson, USGS, 4200 University Dr., Anchorage, AK 99508-4667, e-mail fwilson@usgs.gov, telephone (907) 786-7448.
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Open-file reports include unpublished manuscript reports, maps, and other material that are made available for public consultation at depositories. They are a nonpermanent form of publication that may be cited in other publications as sources of information. Most open-file reports are available from USGS Information Services, Box 25286, Federal Center, Denver, CO 80225 (telephone: 303-202-4210; e-mail: infoservices@usgs.gov).
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Soils in Alaska, and in high latitude terrestrial ecosystems in general, contain significant amounts of organic carbon, most of which is believed to have accumulated since the start of the Holocene about 10 ky before present. High latitude soils are estimated to contain 30-40% of terrestrial soil carbon (Melillo et al., 1995; McGuire and Hobbie, 1997), or ~ 300-400 Gt C (Gt = 1015 g), which equals about half of the current atmospheric burden of carbon. Boreal forests in particular are estimated to have more soil carbon than any other terrestrial biome (Post et al., 1982; Chapin and Matthews, 1993). The relations among net primary production, soil carbon storage, recurrent fire disturbance, nutrients, the hydrologic...
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Descriptions of the [43] mineral occurrences shown on the accompanying figure follow. See U.S. Geological Survey (1996) for a description of the information content of each field in the records. The data presented here are maintained as part of a statewide database on mines, prospects and mineral occurrences throughout Alaska.This and related reports are accessible through the USGS World Wide Web site http://ardf.wr.usgs.gov. Comments or information regarding corrections or missing data, or requests for digital retrievals should be directed to: Frederic Wilson, USGS, 4200 University Dr., Anchorage, AK 99508-4667, e-mail fwilson@usgs.gov, telephone (907) 786-7448.


    map background search result map search result map Where the Stream Meets the Road: Prioritizing Culvert Replacement for Fish Passage - Thesis Environmental and hydrologic overview of the Yukon River Basin, Alaska and Canada Surficial geologic map of the Bettles quadrangle, Alaska Alaska Resource Data File; Chandalar quadrangle Regional Geochemical Results from the Analyses of Rock, Water, Soil, Stream Sediment, and Vegetation Samples -- Fortymile River Watershed, East-Central Alaska, 1998 Sampling Water Quality in the Yukon River Basin Gage Locations (GageLoc.shp) indexed to the NHDPlus Version 2.1 stream network Fate of Carbon in Alaskan Landscapes Project – Database for Soils from Eddy Covariance Tower Sites, Delta Junction, AK Alaska Resource Data File; Survey Pass quadrangle The cold-water climate shield: delineating refugia for preserving salmonid fishes through the 21st century - Publication Fate of Carbon in Alaskan Landscapes Project – Database for Soils from Eddy Covariance Tower Sites, Delta Junction, AK Where the Stream Meets the Road: Prioritizing Culvert Replacement for Fish Passage - Thesis Alaska Resource Data File; Chandalar quadrangle Alaska Resource Data File; Survey Pass quadrangle Surficial geologic map of the Bettles quadrangle, Alaska The cold-water climate shield: delineating refugia for preserving salmonid fishes through the 21st century - Publication Environmental and hydrologic overview of the Yukon River Basin, Alaska and Canada Water Quality in the Yukon River Basin Gage Locations (GageLoc.shp) indexed to the NHDPlus Version 2.1 stream network