Environmental and Hydrologic Overview of the
Yukon River Basin, Alaska and Canada

By Timothy P. Brabets, Bronwen Wang, and Robert H. Meade

Water-Resources Investigations Report 99-4204

This report is also available as a pdf.


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 basinís 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 major rivers flow into the Yukon River. Two of these rivers, the Tanana River and the White River, are glacier-fed rivers and together account for 29 percent of the total water flow of the Yukon. Two others, the Porcupine River and the Koyukuk River, are underlain by continuous permafrost and drain larger areas than the Tanana and the White, but together contribute only 22 percent of the total water flow in the Yukon.

At its mouth, the Yukon River transports about 60 million tons of suspended sediment annually into the Bering Sea. However, an estimated 20 million tons annually is deposited on flood plains and in braided reaches of the river. The waters of the main stem of the Yukon River and its tributaries are predominantly calcium magnesium bicarbonate waters with specific conductances generally less than 400 microsiemens per centimeter. Water quality of the Yukon River Basin varies temporally between summer and winter. Water quality also varies spatially among ecoregions.




Purpose and Scope


Description and History of the Yukon River Basin

The Yukon River and its Major Tributaries

Exploration of the Yukon River Basin

People and Land

Economic Activity

Environmental Characteristics of the Yukon River Basin




Land Cover




Hydrologic Characteristics of the Yukon River Basin

Surface Water

Snow and Ice





Sources of Sediment

Suspended-Sediment Concentrations

Relation Between Suspended-Sediment Concentration and Water Discharge

Suspended-Sediment Discharge

Storage of Sediment


Water Quality

Yukon River Main Stem

Temporal Variations in Water Quality

Spatial Variations in Water Quality

Anthropogenic Effects on Water Quality


References Cited

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For more information about water resources in Alaska is available on the World Wide Web at

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