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

114 Pages·2000·6.19 MB·English

Environmental and Hydrologic Overview of the
Yukon River Basin, Alaska and Canada
Water-Resources Investigations Report 99-4204
U.S. Department of the Interior
U.S. Geological Survey
Cover: Digital elevation model of the Yukon River Basin
Environmental and Hydrologic Overview of the Yukon River Basin,
Alaska and Canada
By Timothy P. Brabets, Bronwen Wang, and Robert H. Meade
________________________________________________________________________________________________
U.S. GEOLOGICAL SURVEY
Water-Resources Investigations Report 99-4204
Anchorage, Alaska
2000
U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBITT, Secretary
U.S. GEOLOGICAL SURVEY
CHARLES G. GROAT, Director
CONTRIBUTING U.S. GEOLOGICAL SURVEY STAFF
Editorial, Graphics, and Text Preparation
E.F. Snyder, Technical Editor
L-L. Harris, Cartographic Technician
For additional information: Copies of this report may be purchased from:
District Chief U.S. Geological Survey
U.S. Geological Survey Branch of Information Services
4230 University Drive, Suite 201 Box 25286
Anchorage, AK 99508-4664 Denver, CO 80225-0286
http://ak.water.usgs.gov
CONTENTS FIGURES
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. Map showing location of the Yukon River Basin in Canada
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 and Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Purpose and Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Map showing digital elevation model of the Yukon River Basin . . 3
Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Graph showing number of growing days for four ecoregions of the
Description and History of the Yukon River Basin . . . . . . . . . . . . . . . . . . 7
Yukon River Basin, 1991-99 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
The Yukon River and its Major Tributaries. . . . . . . . . . . . . . . . . . . . . 7
4. Map showing observed trends of Arctic annual mean
Exploration of the Yukon River Basin . . . . . . . . . . . . . . . . . . . . . . . . 11
temperatures from 1961-90 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
People and Land. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. A. Map showing rivers, lakes, and glaciers of the Yukon
Economic Activity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Environmental Characteristics of the Yukon River Basin . . . . . . . . . . . . . 16
B. Map showing roads and towns in the Yukon River Basin. . . . . 9
Physiography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Climate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 6. Cross sections of the Yukon River above Frank Creek, Yukon
Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Territory, to Pilot Station, Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Land Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 7-18. Maps showing:
Soils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 7. Land ownership of the Yukon River Basin . . . . . . . . . . . . . . . . 13
Permafrost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 8. Physiographic regions of the Yukon River Basin . . . . . . . . . . . 17
Ecoregions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 9. Precipitation regions of the Yukon River Basin . . . . . . . . . . . . 21
Hydrologic Characteristics of the Yukon River Basin . . . . . . . . . . . . . . . . 48
10.Geology of the Yukon River Basin . . . . . . . . . . . . . . . . . . . . . . 23
Surface Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
11.Land cover classes of the Yukon River Basin . . . . . . . . . . . . . . 26
Snow and Ice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
12.Soils of the Yukon River Basin . . . . . . . . . . . . . . . . . . . . . . . . . 29
Streamflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
13.Permafrost regions of the Yukon River Basin . . . . . . . . . . . . . . 33
Floods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
14.Wetland areas of the Yukon River Basin. . . . . . . . . . . . . . . . . . 34
Droughts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
15.Areas of forest fires in the Yukon River Basin . . . . . . . . . . . . . 35
Sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Sources of Sediment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 16.Ecoregions of the Yukon River Basin . . . . . . . . . . . . . . . . . . . . 37
Suspended-Sediment Concentrations. . . . . . . . . . . . . . . . . . . . . . 66 17.Major drainage basins in the Yukon River Basin. . . . . . . . . . . . 49
Relation Between Suspended-Sediment Concentration 18.Location of streamflow-gaging stations with 10 or more
and Water Discharge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 years of record in the Yukon River Basin . . . . . . . . . . . . . . . . . 51
Suspended-Sediment Discharge . . . . . . . . . . . . . . . . . . . . . . . . . 72 19-22. Graphs showing:
Storage of Sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 19.Flow statistics of three rivers near the headwaters of the
Bedload. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Yukon River. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Water Quality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
20.Flow statistics of nine major rivers of the Yukon River Basin . 55
Yukon River Main Stem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
21.Average discharge of the Yukon River at eight locations . . . . . 57
Temporal Variations in Water Quality. . . . . . . . . . . . . . . . . . . . . 94
22.Percent contributions of area and flow of the major drainage
Spatial Variations in Water Quality . . . . . . . . . . . . . . . . . . . . . . . 97
basins of the Yukon River Basin . . . . . . . . . . . . . . . . . . . . . . . . 58
Anthropogenic Effects on Water Quality. . . . . . . . . . . . . . . . . . . 102
23. Map showing percentage of major river outflows into marginal
Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
References Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 seas of the Arctic Ocean. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
24-25. Graphs showing: TABLES
24.Flow statistics of the Salcha River near Salchaket, Alaska. . . . 61
25.Departure from average discharge for several long-term 1. Comparison of salmon harvests for various time periods, Yukon
streamflow-gaging stations in the Yukon River Basin . . . . . . . 63 River Basin, Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
26. Boxplots of suspended-sediment concentration at 14 sites in 2. Watersheds where mining has occurred in the Yukon River
the Yukon River Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Basin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
27-34. Graphs showing: 3. Types and areas of land cover in the Yukon River Basin . . . . . . . . 25
27.Water discharge and suspended-sediment concentrations for 4. Areas of ecoregions in the Yukon River Basin . . . . . . . . . . . . . . . . 36
Chena River at Fairbanks, Alaska and Nenana River near 5. Major drainage basins in the Yukon River Basin . . . . . . . . . . . . . . 48
Healy, Alaska for 1964-66 runoff seasons. . . . . . . . . . . . . . . . . 69 6. Streamflow-gaging stations in the Yukon River Basin with
28. Instantaneous discharge and suspended-sediment concen- 10 or more years of record. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
trations for different particle sizes for Tanana River near 7. Flow contributions of major drainage basins to the Yukon River
Tanacross, Alaska and Tanana River at Fairbanks, Alaska. . . . 70 Basin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
29.Average daily water discharge and suspended-sediment 8. Suspended-sediment stations in the Yukon River Basin . . . . . . . . . 64
concentration for Tanana River near Tanacross, Alaska and 9. Mean grain-size composition of suspended sediment for stations
Yukon River at Eagle, Alaska during 1963 runoff season . . . . 71 in the Yukon River Basin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
30.Seasonal distribution of suspended-sediment discharge for 10. Estimated annual suspended-sediment loads for selected sites in
three rivers in the Yukon River Basin. . . . . . . . . . . . . . . . . . . . 72 the Yukon River Basin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
31.Differences in water discharge and suspended-sediment 11. Water-quality stations in the Yukon River Basin with 10 or
load during water years 1964-66 for Nenana River near more years of record. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Healy, Alaska and Chena River at Fairbanks, Alaska. . . . . . . . 73 12. Summary statistics for selected properties and constituents of
32.Changing proportions of suspended-sediment discharge surface-water samples from stations along the Yukon River. . . . . . 85
during 1954 runoff season in Tanana River near 13. Summary statistics for selected properties and constituents of
Tanacross, Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 surface-water samples from tributaries of the Yukon River . . . . . . 91
33.Annual suspended-sediment loads for 14 sites located in the 14. Comparison of samples taken during open water and under
Yukon River Basin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 ice cover, Yukon River at Pilot Station . . . . . . . . . . . . . . . . . . . . . . 96
34.Suspended-sediment and bedload discharge measured in the 15.Summary statistics for selected properties and constituents of
Tanana River at Fairbanks, Alaska, 1977-82. . . . . . . . . . . . . . . 77 surface-water samples by ecoregion
35. Map showing location of water-quality sampling stations where
one or more samples have been collected in the Yukon River Basin. . 79
36. Map showing location of water-quality sampling stations where
10 or more samples have been collected in the Yukon River Basin . . 80
37. Boxplots of specific conductance from samples taken during open
water and under ice cover on the Yukon River. . . . . . . . . . . . . . . . 95
CONVERSION FACTORS, ABBREVIATED UNITS, AND VERTICAL DATUM
Multiply by To obtain
inch (in.) 25.4 millimeter
foot (ft) 0.3048 meter
mile (mi) 1.609 kilometer
square foot (ft2) 0.09290 square meter
square mile (mi2) 2.590 square kilometer
foot per second (ft/s) 0.3048 meter per second
cubic foot per second (ft3/s) 0.02832 cubic meter per second
inch per year (in/yr) 25.4 millimeter per year
ton 0.9072 megagram
ton per day (ton/d) 0.9072 megagram per day
ton per year (ton/d) 0.9072 megagram per year
foot per mile (ft/mi) 0.1894 meter per kilometer
In this report, temperature is reported in degrees Fahrenheit (°F), which can be converted to degrees Celsius (°C)
by the following equation:
°C = (°F-32)/1.8
OTHER ABBREVIATED UNITS
mg/L, milligram per liter
µg/L, microgram per liter
µS/cm, microsiemen per centimeter at 25 degrees Celsius
mm, millimeter
VERTICAL DATUM
Sea level: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929—A geodetic datum derived
from a general adjustment of the first-order level nets of the United States and Canada, formerly called Sea Level
Datum of 1929.

Environmental and Hydrologic Overview of the Yukon River Basin,
Alaska and Canada
By Timothy P. Brabets, Bronwen Wang and Robert H. Meade
ABSTRACT plains and in braided reaches of the river. The waters of the main
stem of the Yukon River and its tributaries are predominantly cal-
The Yukon River, located in northwestern Canada and cen- cium magnesium bicarbonate waters with specific conductances
tral Alaska, drains an area of more than 330,000 square miles, generally less than 400 microsiemens per centimeter. Water qual-
making it the fourth largest drainage basin in North America. ity of the Yukon River Basin varies temporally between summer
Approximately 126,000 people live in this basin and 10 percent of and winter. Water quality also varies spatially among ecoregions.
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 INTRODUCTION
features of the watershed, such as climate, soils, permafrost, and
Few rivers have the intrinsic allure of the Yukon River. Its
geology.
history, people, and mystique have innate appeal. The Yukon is a
Although the annual mean discharge of the Yukon River near
transportation corridor in a vast area of roadless Alaska. Salmon
its mouth is more than 200,000 cubic feet per second, most of the
species migrate the entire length of the river to spawn and are also
flow occurs in the summer months from snowmelt, rainfall, and
a staple of the subsistence lifestyle of rural villages. Villages and
glacial melt. Eight major rivers flow into the Yukon River. Two of
towns obtain water for drinking from the river and associated aqui-
these rivers, the Tanana River and the White River, are glacier-fed
fers. Recreational activities abound for both residents and tourists.
rivers and together account for 29 percent of the total water flow
However, the river is not benign: flooding and erosion are hazards
of the Yukon. Two others, the Porcupine River and the Koyukuk
to people, buildings, roads, and airfields.
River, are underlain by continuous permafrost and drain larger
The Yukon River Basin (figs. 1 and 2) is located in north-
areas than the Tanana and the White, but together contribute only
western Canada and central Alaska, and is approximately 330,000
22 percent of the total water flow in the Yukon.
mi2 in area. The basin represents one of the largest and most
At its mouth, the Yukon River transports about 60 million
diverse ecosystems in North America. Despite its remoteness and
tons of suspended sediment annually into the Bering Sea. How-
perceived invulnerability, the Yukon River Basin is changing. For
ever, an estimated 20 million tons annually is deposited on flood
example, from 1991 to 1999, the number of growing days in
Introduction 1
160o 72o168o 176o180o176o 168o 160o 152o 144o 136o 128o 120o 72o112o
68o
Arctic Ocean
Russia
64o
Canada
Alaska
Northwest Territories
Yukon River Basin Yu k o n
60o Te r rit o r y
B ritis hm bia
C olu
56o Bering Sea
0 100 200 300 MILES
0 100200300 KILOMETERS
Figure 1. Location of the Yukon River Basin in Canada and Alaska.
2 Environmental and Hydrologic Overview of the Yukon River Basin, Alaska and Canada