U.S. Department of the Interior

U.S. Geological Survey

Hydrologic Data and a Proposed Water-Quality 

Monitoring Network for the Kobuk River Basin, 

Gates of the Arctic National Park and Preserve, 

and Kobuk Valley National Park, Alaska

By TIMOTHY P. BRABETS

Water-Resources Investigations Report 01–4141

Prepared in cooperation with the 

NATIONAL PARK SERVICE

Anchorage, Alaska

2001
U. S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

CHARLES G. GROAT, Director

The use of trade, product, or firm names in this publication is for 

descriptive purposes only and does not imply endorsement by 

the U.S. Government.

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

Internet URLs:

Alaska Water Resources: http://ak.water.usgs.gov

Suggested citation: Brabets, T.P., 2001, Hydrologic data and a proposed water-quality monitoring network for 

the Kobuk River Basin, Gates of the Arctic National Park and Preserve, and Kobuk Valley National Park, Alaska: 

U.S. Geological Survey Water-Resources Investigations Report 01–4141, 23 p.
III

CONTENTS

Abstract .......................................................................................................................................................................................1

Introduction.................................................................................................................................................................................1

Purpose and Scope ............................................................................................................................................................3

Physical Setting...........................................................................................................................................................................3

Surface Water..............................................................................................................................................................................6

Water Quality..............................................................................................................................................................................8

Water-Quality Monitoring Network .........................................................................................................................................16

Classification Analysis....................................................................................................................................................16

Site Selection...................................................................................................................................................................19

Summary and Conclusions........................................................................................................................................................23

References Cited .......................................................................................................................................................................23

FIGURES

1. – 9. Maps showing:

1. Location and extent of the Kobuk River Basin, Gates of the Arctic National Park and Preserve, 

and Kobuk Valley National Park, Alaska ...............................................................................................................2

2. Precipitation regions of the Kobuk River Basin, Alaska ........................................................................................3

3. Topography of the Kobuk River Basin, Alaska......................................................................................................4

4. Physiographic regions of the Kobuk River Basin, Alaska......................................................................................4

5. Land cover of the Kobuk River Basin, Alaska .......................................................................................................5

6. Geology of the Kobuk River Basin, Alaska............................................................................................................5

7. Permafrost regions of the Kobuk River Basin, Alaska ...........................................................................................5

8. Physiographic or soil type regions of the Kobuk River Basin, Alaska...................................................................6

9. Locations of discharge measurements and water-quality sampling sites in the Kobuk River Basin, 

Alaska......................................................................................................................................................................7

10.–11. Graphs showing:

10. Flow statistics for the Kobuk River at Ambler, Alaska, 1965–78 ..........................................................................8

11. Flow statistics for the Kobuk River near Kiana, Alaska, 1976–99.........................................................................8

12.–14. Trilinear diagrams showing:

12. Water chemistry of the Kobuk River at Ambler, Alaska......................................................................................12

13. Water chemistry of the Kobuk River near Kiana, Alaska.....................................................................................12

14. Water chemistry in samples collected basinwide on reconnaissance trip of 1979 ...............................................17

15. Dendrogram of the cluster regions of the Kobuk River Basin, Alaska.......................................................................19

16.–17. Maps showing:

16. Cluster regions of the Kobuk River Basin, Alaska ...............................................................................................20

17. Potential watersheds for water-quality monitoring sites in the Kobuk River Basin, Alaska................................21

TABLES

1. Average and peak discharges for the Kobuk River at Ambler and near Kiana, Alaska ...............................................8

2. Discharge measurement and water-quality sampling sites in the Kobuk River Basin, Alaska ....................................9

3. Discharge measurements at sites in the Kobuk River Basin, Alaska..........................................................................10

4. Water-quality summary for the Kobuk River at Ambler, Alaska...............................................................................11

5. Correlation matrix of specific conductance, instantaneous discharge, and concentrations of major ions 

for the Kobuk River at Ambler, Alaska ......................................................................................................................11

6. Water-quality summary for the Kobuk River near Kiana, Alaska..............................................................................13

7. Correlation matrix of specific conductance, instantaneous discharge, and concentrations of major ions 

for the Kobuk River near Kiana, Alaska.....................................................................................................................14

8. Correlation matrix of iron, manganese, zinc, and suspended sediment concentrations and instantaneous 

discharge for the Kobuk River near Kiana, Alaska ....................................................................................................14

9. Field properties measured at sites in the Kobuk River Basin, Alaska ........................................................................15

10. Major ion concentrations at sites in the Kobuk River Basin, Alaska .........................................................................16

11. Values assigned to different units of geographic information system coverages .......................................................18

12. Potential watersheds for monitoring sites in the Kobuk River Basin, Alaska ............................................................22
IV

CONVERSION FACTORS, VERTICAL DATUM, AND WATER-QUALITY INFORMATION

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

××°F = (1.8 × °C) + 32

VERTICAL DATUM

Sea level: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)—a geodetic 

datum derived from a general adjustment of the first-order level nets of both the United States and Canada, formerly 

called Sea Level Datum of 1929.

ABBREVIATED WATER-QUALITY UNITS

Chemical concentration and water temperature are given only in metric units. Chemical concentration in water is given in 

milligrams per liter (mg/L) or micrograms per liter (μg/L). Milligrams per liter is a unit expressing the solute mass per 

unit volume (liter) of water. One milligram per liter is equivalent to 1,000 micrograms per liter. For concentrations less 

than 7,000 milligrams per liter, the numerical value is about the same as for concentrations in parts per million. Specific 

conductance is given in microsiemens per centimeter (μS/cm) at 25°C.

MAPPING SOURCES:

Base map modified from U.S. Geological Survey 1:63,360 State base maps.

U.S. Geological Survey Digital Line Graphs published at 1:250,000 and 1:63,360.

Publication projection is Albers Equal Area.

Standard parallels are 55°00’ and 65°00’, central meridian–154°00’, latitude of projection origin 50°00’.

Multiply By To obtain

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

square mile (mi2) 2.590 square kilometer (km2)

cubic foot per second (ft3/s) 0.02832 cubic meter per second

 ton 0.9072 megagram
1

Hydrologic Data and a Proposed Water-Quality 

Monitoring Network for the Kobuk River Basin, 

Gates of the Arctic National Park and Preserve, 

and Kobuk Valley National Park, Alaska

By Timothy P. Brabets

Abstract

Located in northwestern Alaska, the Kobuk 

River drains a watershed of approximately 12,300 

square miles. Two national parks are located in the 

basin: the entire Kobuk Valley National Park and 

and a portion of Gates of the Arctic National Park 

and Preserve. Reconnaissance-type water-quality 

data collected on the Kobuk River and some of its 

tributaries indicate that the water is of a calcium to 

calcium-magnesium-bicarbonate type. To design 

a representative water-quality monitoring network, a geographical information system (GIS) of 

the Kobuk River Basin was created. The GIS was 

used with a statistical technique, cluster analysis, 

to stratify the Kobuk River Basin into different 

regions. Potential water-quality monitoring sites 

were then selected from these regions.

INTRODUCTION

The Kobuk River Basin has an area of approximately 12,300 mi2 and is located in northwestern 

Alaska, just north of the Arctic Circle (fig. 1). 

Originating in the central and eastern Brooks Range, 

the Kobuk River flows westward for more than 300 

miles before it enters the Chukchi Sea (fig. 1). Four 

villages are located along the main stem of the Kobuk 

River, and abandoned mining camps and settlements 

are scattered throughout the basin.

Kobuk Valley National Park (KVNP) (fig. 1) 

is approximately 2,700 mi2 in area and is contained 

entirely within the Kobuk River Basin. The portion 

of Gates of the Arctic National Park and Preserve 

(GANPP) commonly referred to as the “boot” covers 

approximately 2,000 mi2

, contains several large lakes 

(Selby, Nutuvukti, and Walker), and is located in the 

eastern part of the basin. In both parks, trees approach 

their northern limit; forest and tundra meet, creating a 

mosaic of forest and open tundra. Thousands of caribou 

funnel through mountain passes and cross the Kobuk 

River on their spring and fall migrations. Salmon and 

Arctic char migrate to spawning grounds within the 

parks. Native people have hunted, fished, and lived 

along the Kobuk River for at least 12,500 years, and 

the subsistence use of resources of the Kobuk River 

Valley continues into the present.

One of the most significant natural changes 

occurring in the Kobuk River Basin is climate warming. Air-temperature records from 1961–90 indicate 

a warming trend on the order of 1.4°F (0.78°C) per 

decade at latitudes where the Kobuk River is located 

(Chapman and Walsh, 1993). Much of the Kobuk River 

is underlain by permafrost, and if the permafrost melts, 

the upper layers of soil will become drier and well 

aerated. Even if permafrost remains as temperatures 

increase, the shallow soils that thaw and freeze each 

year (the active layer) thaw more deeply and develop 

a thicker unsaturated zone. Soil microbes increasingly 

oxidize the organic carbon sequestered in the soils. 

This increased respiration releases carbon, in the form 

of dissolved carbon, into streams and the atmosphere. 
2

Kobuk Valley National Park Gates of the A

 Nation

Ambler

Kobuk

Kiana

Noorvik

LakSelb

Kobuk

River Chukchi Sea

0 10 20 30 40 

0 10 20 30 40 50 KILOMET

ALASKA

Arctic Circle

Brooks Range Chukchi Sea

EXPLANATION

Park boundary

162 ̊

162 ̊

66 ̊

30'

67 ̊

30'

Base map modified from U.S. Geological Survey 1:63,360 State base mapsU.S. Geological Survey Digital Line Graphs published at 1:250,000 and 1:63,360Publication projection is Albers Equal AreaStandard parallels are 55 ̊00' and 65 ̊00', central meridian -154 ̊00', latitude of projection origin 50 ̊00'

Figure 1. Location and extent of the Kobuk River Basin, Gates of the Arctic National Park and Preserve, and Kobuk Valley National Park, Alaska. 
3

Changes in dissolved organic carbon (DOC) could 

affect all trophic levels of stream aquatic communities 

that rely on DOC as a food source.

Private lands totaling about 150 mi2, selected 

under the provisions of the Alaska Native Claims 

Settlement Act (ANCSA), are located in KVNP and 

the portion of GANPP that is part of the Kobuk River 

Basin. In addition, a right-of-way access route to the 

Ambler Mining District along the eastern portion of the 

Kobuk River was reserved in the creation of GANPP. 

These private lands may be developed, possibly 

altering the runoff and water-quality characteristics 

of nearby streams and rivers.

Water-quality and quantity information is needed 

on the Kobuk River to monitor possible future climate 

change and potential development. By collecting and 

analyzing data before development takes place, park 

managers will have a baseline with which to compare 

future impacts. Proper data reduction and analysis can 

help ensure that the correct data have been collected, 

determine whether more or different types of data collection are needed, and indicate trends in water quality 

and whether these trends are occurring naturally or by 

human activity. To date, a water-quality monitoring 

plan has not been developed for the Kobuk River 

Basin.

Purpose and Scope

This report (1) summarizes the hydrologic data 

that have been collected in the Kobuk River Basin 

and (2) proposes a conceptual water-quality monitoring network for the streams and rivers of KVNP and 

GANPP. Only previously existing data were used in 

this study. Since the portion of the Kobuk River downstream of the western boundary of KVNP is outside 

both national parks (fig. 1), this area was not included 

in the analysis; the remaining portion of the Kobuk 

River Basin used in this study was approximately 

9,500 mi2

.

The operation of a water-quality monitoring 

network would also include collection of continuous 

streamflow data from a subset of the water-quality 

monitoring sites and limnology data from a subset 

of the lakes in KVNP and GANPP. Identification 

of potential gaging sites and lakes was beyond the 

scope of this study. However, La Perriere (1999) 

studied a number of lakes in GANPP that are located 

in the Kobuk River Basin and developed a monitoring 

plan for these lakes. 

PHYSICAL SETTING

Located in the central and eastern Brooks Range 

in northwestern Alaska, the Kobuk River Basin has 

a continental climate with short, warm summers, and 

long, very cold winters. Precipitation ranges from 

15 to 40 inches, with an average of 21 inches for 

the entire basin (fig. 2). Average basin elevation for 

the Kobuk River Basin is about 1,300 feet and ranges 

from approximately 0 to 11,400 feet (fig. 3). The 

topography of the basin consists of low, generally 

rolling mountains (35 percent), plains and lowlands 

(29 percent), moderately high rugged mountains 

(21 percent), and plateaus and highlands of rolling 

topography and gentle slopes (15 percent) (fig. 4). 

Kobuk Valley

 National Park

Gates of the Arctic

 National Park and Preserve

Ambler

Kobuk

Walker

Lake

Nutuvukti

Lake

Norutak

Lake

Lake 

Selby

Kobuk

River

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

160 ̊

160 ̊ 67 ̊

30'

67 ̊

00'

66 ̊

30'

67 ̊

30'

154 ̊

154 ̊

EXPLANATION

Mean annual precipitation

 15-20

 20-30

 30-40

Figure 2. Precipitation regions 

of the Kobuk River Basin, 

Alaska (from Jones and Fahl, 

1994). 
4

Kobuk Valley

 National Park

Gates of the Arctic

 National Park and Preserve

Ambler

Kobuk

Walker

Lake

Nutuvukti

Lake

Norutak

Lake

Lake 

Selby

Kobuk

River

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

160 ̊

160 ̊ 67 ̊

30'

67 ̊

00'

66 ̊

30'

67 ̊

30'

154 ̊

154 ̊

EXPLANATION

Highest elevation

Lowest elevation

Figure 3. Topography of the Kobuk River 

Basin, Alaska. 

EXPLANATION

Physiographic regions

 Moderately high rugged mountains (21 percent)

 Low mountains, generally rolling (35 percent)

 Plateaus and highlands of rolling topography 

 and gentle slopes (15 percent)

 Plains and lowlands (29 percent)

Kobuk Valley

 National Park

Gates of the Arctic

 National Park and Preserve

Ambler

Kobuk

Walker

Lake

Nutuvukti

Lake

Norutak

Lake

Lake 

Selby

Kobuk

River

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

160 ̊

160 ̊ 67 ̊

30'

67 ̊

00'

66 ̊

30'

67 ̊

30'

154 ̊

154 ̊

Figure 4. Physiographic regions of the 

Kobuk River Basin, Alaska (from 

Wahrhaftig, 1965). 

Land cover categories for the Kobuk River Basin 

consist primarily of tall and low shrub (31 percent), 

dry or moist herbaceous (31 percent), needleleaf forest 

(26 percent), and dwarf shrub (10 percent) (fig. 5). 

Tall and low shrubs consist of willows and alders, 

dry or moist herbaceous plants consist of sedges, 

needleleaf forests consist of white and black spruce, 

and dwarf shrubs consist of plants less than 0.6 feet that 

are predominantly dwarf birch. 

The geology of the Kobuk River Basin is 

composed primarily of Mesozoic sedimentary rocks 

(31 percent), Mesozoic volcanic rocks (15 percent), 

Paleozoic sedimentary rocks (32 percent), and 

Precambrian rocks (18 percent) (fig. 6). Mesozoic 

sedimentary rocks consist of shale, sandstone, 

conglomerate, bentonite, clay, and coal. Mesozoic 

volcanic rocks consist of basalt, diabase, diorite, 

gabbro, chert, and dunite. Paleozoic rocks consist of 

shale, sandstone, chert, conglomerates, and quartzite. 

Precambrian rocks consist of quartz-mica schist, mafic 

greenschist, calcareous schist, chloritic schist, phyllite, 

and quartzite.

Much of the Kobuk River Basin (83 percent) 

is underlain by continuous permafrost (fig. 7). A 

mass of material is considered to be permafrost if it 

has a temperature continually at or below 32°F (0°C) 

for 2 or more years (Ferrians, 1965). Permafrost has 

a very low permeability and commonly acts as a barrier 

to infiltration and as a confining layer to aquifers. 

Because permafrost is a barrier to infiltration, the 

likelihood of flash floods is greater in streams draining 

permafrost areas.
5

Kobuk Valley

 National Park

Gates of the Arctic

 National Park and Preserve

Ambler

Kobuk

Walker

Lake

Nutuvukti

Lake

Norutak

Lake

Lake 

Selby

Kobuk

River

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

160 ̊

160 ̊ 67 ̊

30'

67 ̊

00'

66 ̊

30'

67 ̊

30'

154 ̊

154 ̊

EXPLANATION

Land cover

 Needleleaf forest (26 percent)

 Dwarf shrub (10 percent)

 Dry or moist herbaceous (31 percent)

 Tall and low shrub (31 percent)

 Forest fires (Less than 1 percent)

 Water (Less than 1 percent)

Figure 5. Land cover of the Kobuk 

River Basin, Alaska (from Alaska 

Geospatial Data Clearinghouse, 1998). 

Kobuk Valley

 National Park

Gates of the Arctic

 National Park and Preserve

Ambler

Kobuk

Walker

Lake

Nutuvukti

Lake

Norutak

Lake

Lake 

Selby

Kobuk

River

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

160 ̊

160 ̊ 67 ̊

30'

67 ̊

00'

66 ̊

30'

67 ̊

30'

154 ̊

154 ̊

EXPLANATION

Geologic unit

 Cenozoic volcanic rocks (Less than 1 percent)

 Mesozoic sedimentary rocks (31 percent)

 Mesozoic volcanic rocks (15 percent)

 Mesozoic intrusive rocks (4 percent)

 Paleozoic sedimentary rocks (32 percent)

 Precambrian volcanic rocks (18 percent)

Figure 6. Geology of the Kobuk River 

Basin, Alaska (from Silbererling and 

others, 1994). 

Kobuk Valley

 National Park

Gates of the Arctic

 National Park and Preserve

Ambler

Kobuk

Walker

Lake

Nutuvukti

Lake

Norutak

Lake

Lake 

Selby

Kobuk

River

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

160 ̊

160 ̊ 67 ̊

30'

67 ̊

00'

66 ̊

30'

67 ̊

30'

154 ̊

154 ̊

EXPLANATION

Permafrost region

 Mountainous area, generally underlain by 

 continuous permafrost (58 percent)

 Mountainous area, generally underlain by 

 discontinuous permafrost (5 percent)

 Lowland and upland area, generally underlain 

 by continuous permafrost (25 percent)

 Lowland and upland area, generally underlain 

 by discontinuous permafrost (12 percent)

Figure 7. Permafrost regions of the Kobuk 

River Basin, Alaska (from Ferrians, 1965). 
6

Kobuk Valley

 National Park

Gates of the Arctic

 National Park and Preserve

Kobuk

River

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

160 ̊

160 ̊ 67 ̊

30'

67 ̊

00'

66 ̊

30'

67 ̊

30'

154 ̊

154 ̊

EXPLANATION

Physiography or soil type 

(Carbon content in pounds 

 per square foot) 

 Dune lands (Less than .2)

 Gelisols (.2 to 2)

 Inceptisols (2 to 4)

 Rough mountainous lands 

 (More than 4)

Figure 8. Physiographic or 

soil type regions of the 

Kobuk River Basin, Alaska 

(from Wahrhaftig, C., 1965; 

and the U.S. Department of 

Agriculture, 1975, respectively).

Because the Kobuk River Basin is dominated 

by permafrost, most of the soils are classified as 

gelisols (fig. 8). These are soils that have permafrost 

within about 40 inches of the soil surface and (or) 

have gelic materials within about 40 inches of the soil 

surface and have permafrost within about 80 inches.

A suborder of the gelisol soils known as histic pergelic 

cryaquepts have thick accumulations of organic matter 

on the soil surface, commonly in the form of a mat 

of slightly or partly decomposed mosses, sedges, 

and associated plants. Because the mat is effective 

insulation against summer heat, the permafrost table 

in these soils is normally very shallow. The upper 

part of the soil that thaws each summer and refreezes 

each winter, known as the active layer, is almost 

constantly saturated during the thaw period. These 

soils contain varying amounts of carbon, ranging 

from less than 0.2 lb/ft2

 to more than 4 lb/ft2 (fig. 8). 

The total amount of carbon held in the soil of the 

Kobuk River Basin is estimated to be approximately 36 

million tons (National Resource Conservation Service, 

2000).

SURFACE WATER

Flow characteristics of the Kobuk River are 

similar to those of other large Arctic rivers in Alaska 

and can be illustrated by flow records from the Kobuk 

River at Ambler (site 29, fig. 9, fig. 10) and the Kobuk 

River near Kiana (site 37, fig. 9, fig. 11). Late October 

to late May is a period of relatively low flow. In late 

May, when the snowpack has reached melting stage, 

flow in the Kobuk River begins to increase rapidly. 

Most of the runoff from the basin occurs during June 

as the water from snowmelt enters the river. For the 

remainder of the summer, July through September, 

flow fluctuates depending on the amount of precipitation. In October, flow begins to decrease with the onset 

of winter and the process repeats itself.

The average annual flow for the Kobuk River 

near Ambler has ranged from 5,839 ft3/s to 14,890 ft3

/s 

for the period 1966–78 (table 1). Average annual 

flow for the Kobuk River near Kiana has ranged from 

10,020 ft3

/s to 24,960 ft3/s for the period 1977–99 

(table 1). Peak discharges at the Kobuk River at 

Ambler have ranged from 30,000 ft3/s to 95,000 ft3/s 

and at the Kobuk River near Kiana from 45,000 ft3/s to 

161,000 ft3/s (table 1). Some peaks were the result of 

ice jams that occurred during breakup. Large volumes 

of water are released when the ice jams fail.

In addition to the continuous flow records near 

Ambler and near Kiana, discharge data have been collected at 35 additional sites in the Kobuk River Basin 

(fig. 9, table 2). Most of the flow measurements were 

made on reconnaissance trips during the summer of 

1979 and the winter of 1980 (Childers and Kernodle, 

1983) and in 1994 (Deschu and others, 1999). Childers 

and Kernodle noted that frequent, heavy rains occurred 

during the middle and latter part of August 1979, 

and thus streamflow was probably higher than normal.
7

Kobuk Valley National Park

Gates of the Arctic National Park 

Ambler

Kobuk

Lake Selby

Kobuk

River

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

160 ̊

160 ̊

67 ̊

30'

67 ̊

00'

15

16

13

37

36

35

34

32

33 30

31

29 27

28

26

25

24

23

22

21

20

19

17

18 1

28

1

EXPLANATION

Discharge measurement or water-quality site with  site number

Figure 9. Locations of discharge measurements and water-quality sampling sites in the Kobuk River Basin, Alaska. 
8

100

100,000

200

500

1,000

2,000

5,000

10,000

20,000

50,000

DAILY DISCHARGE, IN CUBIC FEET PER SECOND

MONTH

Minimum

Mean

Maximum

O N D J F M A M J J A S

Figure 10. Flow statistics for the Kobuk River at Ambler, Alaska, 

1965–78. 

1,000

1,000,000

2,000

5,000

10,000

20,000

50,000

100,000

200,000

500,000

DAILY DISCHARGE, IN CUBIC FEET PER SECOND

Minimum

Mean

Maximum

ONDJ F M

MONTH

A MJ J A S

Figure 11. Flow statistics for the Kobuk River near Kiana, Alaska, 

1976–99. 

Unit runoff for the Kobuk River tributaries ranged 

from 0.1 ft3

/s/mi2 to 12.2 ft3/s/mi2. Data from both 

reconnaissance trips indicated that most major tributaries draining from high relief areas had higher unit 

runoff than tributaries draining the lower relief areas 

(table 3). For example, the Pah River, which drains 

a lowland area of 956 mi2

, had a unit runoff of only 

0.48 ft3/s/mi2

. Other tributaries, which drain high 

relief areas, had unit runoff greater than 2.0 ft3

/s/mi2.

WATER QUALITY

Water-quality data are available for the 

Kobuk River at Ambler for 1967–77, from the 

Kobuk River near Kiana for 1975–81, and from 

the reconnaissance trips in 1979 (Childers and Kernodle, 1983) and 1994 (Deschu and others, 1999).

Table 1. Average and peak discharges for the Kobuk River 

at Ambler and near Kiana, Alaska

[ft3/s, cubic foot per second; --, no data] 

Water 

year

Average 

discharge

(ft3

/s)

Peak

discharge

(ft3

/s)

Ambler Kiana Ambler Kiana

1966 8,675 -- 63,900 --

1967 13,340 -- 81,500 --

1968 9,601 -- 94,000 --

1969 5,839 -- 35,900 --

1970 6,220 -- 155,000

1Maximum daily discharge. 

--

1971 9,203 -- 195,000 --

1972 9,025 -- 190,000 --

1973 14,890 -- 93,600 --

1974 8,532 -- 64,200 --

1975 8,760 -- 66,700 --

1976 6,045 -- 36,600 --

1977 7,279 10,020 39,100 69,300

1978 7,742 12,450 130,000 48,000

1979 -- 20,380 -- 109,000

1980 -- 18,050 -- 99,600

1981 -- 13,940 -- 77,200

1982 -- 18,360 -- 152,000

1983 -- 13,640 -- 82,000

1984 -- 12,900 -- 80,700

1985 -- 15,130 -- 146,000

1986 -- 17,120 -- 141,000

1987 -- 11,370 -- 145,000

1988 -- 13,590 -- 284,000

2

Estimated.

1989 -- 22,410 -- 151,000

1990 -- 13,260 -- 1130,000

1991 -- 15,870 -- 1120,000

1992 -- 12,220 -- 161,000

1993 -- 19,470 -- 139,000

1994 -- 24,960 -- 138,000

1995 -- 12,080 -- 1110,000

1996 -- 13,080 -- 142,000

1997 -- 10,640 -- 166,000

1998 -- 20,130 -- 103,000

1999 -- 13,270 -- 70,000

2000 -- -- -- --
9

Table 2. Discharge measurement and water-quality sampling sites in the Kobuk River Basin, Alaska

[USGS site ID, U.S. Geological Survey site identification number; *, asterisk indicates water-quality sampling site]

Map number

(figure 9) Site USGS site ID

Drainage area

(square miles)

1 Kobuk River above Walker Lake outlet 6701371542036 285

2 * Walker Lake outlet 6703291541849 178

3 * Kobuk River below Walker Lake 6657471542148 285

4 * Meandering tributary 6657221542545 43.0

5 * Red Bog tributary 6655031542904 28.8

6 Nutuvukti Lake outlet 6657191543550 29.0

7 * Nutuvukti Lake tributary 6655031543038 69.4

8 * Kobuk River above Lower Kobuk Canyon 6650061543900 714

9 * Beaver Pond tributary 6647301544550 6.70

10 * Norutak Hills tributary 6647371544712 22.5

11 * Reed River near mouth 6649251545731 364

12 Minakokosa Lake outlet 6654231550044 33.0

13 * Beaver Creek 6649021550223 282

14 Kobuk River above Sulakpoatokvik Creek 6646361551018 1,560

15 * Tributary near Bear Island 6645121551606 52.8

16 * Akpelik Creek 6645041552137 37.3

17 Selby Lake outlet 6651041554104 113

18 Kobuk River below Selby River 6646181555000 2,000

19 * Pah River near mouth 6644301560348 956

20 Killak River near mouth 6648541560500 42.0

21 Mauneluk River near mouth 6652401561645 573

22 Kollioksak Lake outlet 6659431562631 6.00

23 * Kogoluktuk River near mouth 6656421564506 626

24 * Kobuk River above Kobuk 6654121565306 4,170

25 * Ruby Creek at Bornite 6704361565612 13.0

26 Shungnak River near mouth 6656471571903 213

27 Ambler River above Redstone River 6709181573223 716

28 Redstone River near Ambler 6712011573605 211

29 * Kobuk River at Ambler 15744000 6,570

30 Jade Creek near Ambler 6710491580747 57.0

31 * Kobuk River below Jade Creek 6706351581451 6,720

32 Akillik River above Hunt River 6714221582805 303

33 Hunt River near Ambler 6711541583242 646

34 * Kavet Creek at mouth 6707241590130 25.0

35 * Salmon River above Kitlik River 6715121593858 515

36 * Kitlik River near Kiana 6714301594006 98.0

37 * Kobuk River near Kiana 15744500 9,520
10

Table 3. Discharge measurements at sites in the Kobuk River Basin, Alaska

[ft3/s/ cubic foot per second; ft3/s/mi2, cubic foot per second per square mile]

Map number 

(figure 9) Site Date

Discharge

(ft3

/s)

Unit discharge

(ft3

/s/mi2)

1 Kobuk River above Walker Lake outlet 8-11-79 1,090 3.82

2 Walker Lake outlet 8-11-79

6-14-94

1,160

12,000

1

Estimated.

6.52

11.2

3 Kobuk River below Walker Lake 6-15-94 15,000 17.5

4 Meandering tributary 6-15-94 200 4.65

5 Red Bog tributary 6-16-94 10 0.34

6 Nutuvukti Lake outlet 8-14-79 47 1.62

7 Nutuvukti Lake tributary 6-16-94 260 3.75

8 Kobuk River above Lower Kobuk Canyon 8-13-79 2,380 3.33

10 Norutak Hills tributary 6-17-94 37 1.64

11 Reed River near mouth 8-15-79

6-18-94

1,640

12,000

4.51

5.49

12 Minakokosa Lake outlet 8-14-79 88 2.70

13 Beaver Creek 6-18-94 11,700 6.03

14 Kobuk River above Sulakpoatokvik Creek 8-16-79 6,930 4.45

15 Tributary near Bear Island 6-19-94 29 0.55

16 Akpelik Creek 6-19-94 114 3.06

17 Selby Lake outlet 8-16-79 332 2.94

18 Kobuk River below Selby Lake 8-17-79 7,240 3.62

19 Pah River near mouth 8-17-79 458 0.48

20 Killak River near mouth 8-18-79 92 2.19

21 Mauneluk River near mouth 8-18-79 2,980 5.20

22 Kollioksak Lake outlet 8-18-79 .5 0.08

23 Kogoluktuk River near mouth 8-19-79

4-02-80

2,540

63

4.06

0.10

24 Kobuk River above Kobuk 8-24-79

4-02-80

21,900

1,240

5.25

0.30

25 Ruby Creek at Bornite 8-21-79 80 6.15

26 Shungnak River near mouth 8-23-79 1,520 7.14

27 Ambler River above Redstone River 8-19-79 5,030 7.03

28 Redstone River near Ambler 8-22-79 1,100 5.21

30 Jade Creek near Ambler 8-22-79 150 2.63

31 Kobuk River below Jade Creek 8-28-79 50,800 7.56

32 Akillik River above Hunt River 8-22-79 3,700 12.2

33 Hunt River near Ambler 3-28-80 164 0.24

34 Kavet Creek 8-29-79 55 2.20

35 Salmon River above Kitlik River 8-23-79 4,400 8.54

36 Kitlik River near Kiana 8-23-79 851 8.68
11

Most of the data consist of field parameters (pH, water 

temperature, specific conductance, and dissolved 

oxygen) and major ions (tables 4 and 5). Some traceelement data are available for the Kobuk River near 

Kiana.

The trilinear diagram in figure 12 (Piper, 1944) 

indicates that the water chemistry of the Kobuk River 

at Ambler is of a calcium to calcium-magnesiumbicarbonate type. High correlations exist between the 

concentrations of major ions (table 4) and specific 

conductance (table 5). Conductance is inversely 

correlated with discharge, indicating that concentrations of these constituents become more dilute 

with increasing discharge. 

Analysis of water-quality samples from the 

Kobuk River near Kiana indicates the same type of 

water as found upstream at Ambler (fig. 13, table 6). 

Table 4. Water-quality summary for the Kobuk River at Ambler, Alaska

[μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; mg/L, milligrams per liter]

Constituent

Number 

of samples Minimum Median Maximum

pH 15 6.7 7.7 8.4

Specific conductance (μS/cm) 28 59 150 212

Water temperature (°C) 30 0.0 4.8 19.0

Hardness (mg/L as CaCO3) 15 28 79 110

Calcium (mg/L) 15 9.0 25 34

Magnesium (mg/L) 15 1.3 4.0 5.9

Potassium (mg/L) 15 0.2 .5 1.3

Sodium (mg/L) 15 0.3 1.0 2.1

Alkalinity (mg/L) 14 28 71 100

Chloride (mg/L) 15 0.0 0.4 1.0

Fluoride (mg/L) 15 0.0 0.1 0.2

Silica (mg/L) 15 1.1 3.3 6.8

Sulfate (mg/L) 15 0.0 11 17

Table 5. Correlation matrix of specific conductance, instantaneous discharge, and concentrations of major ions for the Kobuk River at 

Ambler, Alaska

[Number of samples = 15; degrees of freedom = 13; correlation coefficient greater than or equal to 0.51 is significant at the 95 percent confidence limit]

Constituent

Specific

conductance

Instantaneous

discharge Calcium Magnesium Potassium Sodium Alkalinity Chloride Fluoride Silica Sulfate

Specific 

conductance 1.00

Instantaneous 

discharge -0.87 1.00

Calcium 0.99 -0.88 1.00

Magnesium 0.98 -0.83 0.96 1.00

Potassium 0.73 -0.54 0.70 0.73 1.00

Sodium 0.89 -0.68 0.88 0.86 0.79 1.00

Alkalinity 0.98 -0.83 0.98 0.97 0.74 0.86 1.00

Chloride -0.03 0.11 -0.03 -0.04 -0.23 0.01 -0.01 1.00

Fluoride 0.24 -0.13 0.26 0.14 0.34 0.40 0.19 -0.02 1.00

Silica 0.86 -0.73 0.86 0.85 0.62 0.88 0.87 -0.01 0.11 1.00

Sulfate 0.81 -0.86 0.79 0.76 0.53 0.72 0.70 -0.22 0.41 0.63 1.00
12

SULFATE PLUS CHLORIDE

CALCIUM PLUS MAGNESIUM

SODIUM PLUS POTASSIUM

ALKALINITY

PERCENT

PERCENT

PERCENT

SULFATE

MAGNESIUM

CALCIUM CHLORIDE, FLUORIDE, NO2 + NO3

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100 100

80 80

60 60

40 40

20 20

0 100

80

0

60

40

20

0

100

20

40

60

80

0

A B

The corner A coresponds to 100 percent Mg 

in the cation triangle, 100 percent (Ca+Mg), 

0 percent (Na+K); 100 percent alkalinity, 0 

percent (SO4 +Cl) in the quadrilateral.

The corner B is 100 percent SO4 

in the anion triangle, 100 

percent (Na+K), 0 percent 

(Ca+Mg); 100 percent (SO4 +Cl), 

0 percent alkalinity in the 

quadrilateral.

Figure 12. Water chemistry of the 

Kobuk River at Ambler, Alaska. 

SULFATE PLUS CHLORIDE

CALCIUM PLUS MAGNESIUM

SODIUM PLUS POTASSIUM

PERCENT

PERCENT

PERCENT

SULFATE

MAGNESIUM

CALCIUM CHLORIDE, FLUORIDE, NO2 + NO3

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100 100

80 80

60 60

40 40

20 20

0 100

80

0

60

40

20

0

100

20

40

60

80

0

ALKALINITY

Figure 13. Water chemistry of the 

Kobuk River near Kiana, Alaska. 
13

Table 6. Water-quality summary for the Kobuk River near Kiana, Alaska

[μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; mg/L, milligrams per liter; μg/L; micrograms per liter]

Constituent or property

Number 

of samples Minimum Median Maximum

Nondetections

PROPERTIES

pH 25 6.2 7.1 8.0 0

Specific conductance (μS/cm) 26 85 157 205 0

Water temperature (°C) 27 0.0 4.5 16.0 0

Hardness (mg/L as CaCO3) 26 41 79 110 0

MAJOR IONS

Calcium (mg/L) 26 13 25.0 34 0

Magnesium (mg/L) 26 2.1 4.1 6.3 0

Potassium (mg/L) 26 0.2 0.5 2.2 0

Sodium (mg/L) 26 0.6 0.9 2.5 0

Alkalinity (mg/L) 26 30 66 110 0

Chloride (mg/L) 26 0.1 0.6 2.9 0

Fluoride (mg/L) 19 0.1 0.1 0.1 4

Silica (mg/L) 26 2.2 3.4 6.1 0

Sulfate (mg/L) 25 4.4 13.0 27.0 0

NUTRIENTS

Total nitrogen, NO2 + NO3 (mg/L) 25 0.09 0.17 1.6 0

Total nitrogen as N (mg/L) 24 0.09 0.46 2.5 0

Total nitrogen as NO3 (mg/L) 24 0.40 2.0 11.0 0

CARBON

Organic carbon, Dissolved (mg/L) 8 2.5 7.4 15.0 1

Organic carbon, suspended (mg/L) 6 0.3 0.6 0.8 2

Organic carbon, total (mg/L) 14 0.5 2.6 10.0 0

SELECTED TRACE ELEMENTS

Arsenic, total (μg/L) 16 1 1 9 0

Copper, dissolved (μg/L) 12 2 6 32 4

Copper, suspended (μg/L) 12 5 7 41 2

Copper, total (μg/L) 12 5 13.5 50 3

Iron, dissolved (μg/L) 16 30 90 450 0

Iron, suspended (μg/L) 8 190 350 3,200 0

Iron, total (μg/L) 16 250 430 3,300 0

Lead, dissolved (μg/L) 12 2 6 11 3

Lead, suspended (μg/L) 11 8 17 32 4

Lead, total (μg/L) 11 7 18 38 4

Manganese, total (μg/L) 16 20 30 110 0

Zinc, dissolved (μg/L) 11 6.0 20 90 5

Zinc, suspended (μg/L) 10 10 30 470 6

Zinc, total (μg/L) 14 10 30 560 2
14

Similar to the Kobuk River at Ambler, dissolved constituents from the Kobuk River near Kiana are correlated to specific conductance and inversely correlated 

with discharge (table 7). Two trace elements, iron and 

manganese, and suspended sediment are somewhat 

correlated with discharge (table 8). Iron and zinc are 

correlated with suspended sediment. 

Water samples collected during the reconnaissance trips in August 1979 and June 1999 provide a

good “snapshot” of the water quality of the Kobuk 

River Basin. Water temperatures during the time 

of sampling ranged from 5.2°C to 17.5°C (table 9). 

Stream sampling sites near lake outlets had the warmest water. Concentrations of dissolved oxygen ranged 

from 7.5 mg/L to 13.5 mg/L. Values of pH ranged from 

6.2 to 7.9, and specific conductance of water ranged 

from 45 μS/cm to 235 μS/cm. Major-ion analysis of 

water samples collected at some of the sites (table 10) 

indicated that most waters sampled are of the calciummagnesium to calcium-bicarbonate type (fig. 14). 

Table 7. Correlation matrix of specific conductance, instantaneous discharge, and concentrations of major ions for the Kobuk River near 

Kiana, Alaska

[Number of samples = 26; degrees of freedom = 24; correlation coefficient greater than or equal to 0.39 is significant at the 95 percent confidence limit]

Constituent

Specific

conductance

Instantaneous

discharge Calcium Magnesium Potassium Sodium Alkalinity Chloride Fluoride Silica Sulfate

Specific

conductance 1.00

Instantaneous 

discharge -0.86 1.00

Calcium 0.92 -0.90 1.00

Magnesium 0.89 -0.87 0.97 1.00

Potassium 0.32 -0.39 0.52 0.61 1.00

Sodium 0.45 -0.50 0.60 0.70 0.78 1.00

Alkalinity 0.84 -0.82 0.92 0.88 0.47 0.58 1.00

Chloride 0.22 -0.32 0.27 0.31 0.18 0.03 0.21 1.00

Fluoride -0.27 0.18 -0.23 -0.34 -0.14 -0.51 -0.14 0.01 1.00

Silica 0.78 -0.68 0.84 0.86 0.44 0.64 0.85 0.04 -0.37 1.00

Sulfate 0.21 -0.19 0.11 0.16 -0.14 0.14 0.04 -0.07 -0.44 0.05 1.00

Table 8. Correlation matrix of iron, manganese, zinc, and suspended sediment concentrations and instantaneous discharge for the 

Kobuk River near Kiana, Alaska

[Number of samples = 14; degrees of freedom = 12; correlation coefficient greater than or equal to 0.53 is significant at the 95 percent confidence limit] 

Constituent Iron Manganese Zinc

Suspended

sediment

Instantaneous

discharge

Iron 1.00

Manganese 0.87 1.00

Zinc 0.34 0.08 1.00

Suspended sediment 0.78 0.53 0.81 1.00

Discharge 0.89 0.79 0.14 0.63 1.00
15

Table 9. Field properties measured at sites in the Kobuk River Basin, Alaska

[ft3/s, cubic foot per second; mg/L, milligram per liter; °C, degrees Celsius; μS/cm, microsiemens per centimeter at 25°C; NTU, nepthelometric turbidity 

unit; --, not measured; <, less than]

Map 

number

(figure 9) Site Date

Discharge

(ft3

/s)

Dissolved

oxygen

(mg/L) pH

Specific

conductance

(μS/cm)

Turbidity

(NTU)

Water

temperature

(°C)

1 Kobuk River above Walker Lake outlet 8-11-79 1,090 -- 7.7 175 0.25 10.5

2 Walker Lake outlet 8-11-79

6-14-94

1,160

12,000

1Estimated.

--

--

7.9

7.7

130

153

0.18

<0.20

14.5

5.2

3 Kobuk River below Walker Lake 6-15-94 15,000 -- 7.7 137 <0.20 6.0

4 Meandering tributary 6-15-94 200 -- 6.9 77 1.5 7.0

5 Red Bog tributary 6-16-94 10 -- 6.2 181 1.6 12.1

6 Nutuvukti Lake outlet 8-14-79 47 -- 6.8 65 0.35 17.5

7 Nutuvukti Lake tributary 6-16-94 260 -- 6.9 64 0.50 11.1

8 Kobuk River above Lower Kobuk Canyon 8-13-79 2,380 -- 7.9 160 0.35 14.0

9 Beaver Pond tributary 6-17-94 -- -- 7.2 179 0.80 7.4

10 Norutak Hills tributary 6-17-94 37 -- 7.5 148 34.0 8.2

11 Reed River near mouth 8-15-79

6-18-94

1,640

1

2,000

--

--

7.2

7.5

110

105

0.30

1.00

9.5

7.5

12 Minakokosa Lake outlet 8-14-79 88 -- 7.7 70 0.35 16.0

13 Beaver Creek 6-18-94 11,700 -- 7.4 108 1.0 7.7

14 Kobuk River above Sulakpoatokvik Creek 8-16-79 6,930 -- 7.3 135 0.45 10.5

15 Tributary near Bear Island 6-19-94 29 -- 7.1 124 0.30 6.6

16 Akpelik Creek 6-19-94 114 -- 7.2 62 <0.20 5.6

17 Selby Lake outlet 8-16-79 332 -- 7.5 85 0.30 17.0

18 Kobuk River below Selby River 8-17-79 7,240 -- 7.5 135 0.30 13.0

19 Pah River near mouth 8-17-79 458 -- 7.1 80 0.85 13.5

20 Killak River near mouth 8-18-79 92 13.5 6.5 55 0.50 7.5

21 Mauneluk River near mouth 8-18-79 2,980 -- 7.4 155 0.65 9.0

22 Kollioksak Lake outlet 8-18-79 0.5 7.5 6.2 45 2.0 13.5

23 Kogoluktuk River near mouth 8-19-79 2,540 11.8 7.3 180 0.85 9.0

24 Kobuk River above Kobuk 8-24-79 21,900 11.0 7.3 165 0.20 12.0

25 Ruby Creek at Bornite 8-21-79 80 11.6 7.5 235 0.20 6.5

26 Shungnak River near mouth 8-23-79 1,520 12.9 7.6 127 0.40 11.0

27 Ambler River above Redstone River 8-19-79 5,030 11.4 7.9 170 0.40 10.0

28 Redstone River near Ambler 8-22-79 1,100 12.1 7.0 100 0.50 8.0

28 Kobuk River at Ambler 8-27-79 -- 11.3 7.5 150 2.0 8.5

30 Jade Creek near Ambler 8-22-79 150 12.2 6.8 62 0.40 6.5

31 Kobuk River below Jade Creek 8-28-79 50,800 11.6 7.7 145 0.70 9.0

32 Akillik River above Hunt River 8-22-79 3,700 11.8 6.9 95 0.80 7.0

34 Kavet Creek at mouth 8-29-79 55 11.3 7.8 220 3.5 8.0

35 Salmon River above Kitlik River 8-23-79 4,400 11.8 7.5 185 0.60 7.5

36 Kitlik River near Kiana 8-23-79 851 11.6 6.5 55 0.15 7.5

37 Kobuk River near Kiana 8-30-79 -- 11.1 7.5 230 0.30 9.0
16

Table 10. Major ion concentrations at sites in the Kobuk River Basin, Alaska

[fig., figure; --, no data; <, less than]

Map

number

(fig. 9) Site Date

Constituent (milligrams per liter)

Calcium Magnesium Sodium Potassium Chloride Sulfate Fluoride Silica

Dissolved

solids

2 Walker Lake outlet 8-11-79

6-14-94

23

22

2.5

3.1

0.6

0.52

1.1

1.2

0.2

0.3

11

8.6

0.1

--

2.0

--

70

--

3 Kobuk River below 

Walker Lake 6-15-94 21 2.8 0.40 0.9 <0.1 7.0 -- -- --

4 Meandering tributary 6-15-94 11 1.6 0.41 <0.5 0.3 6.0 -- -- --

5 Red Bog tributary 6-16-94 23 7.8 3.5 <0.5 0.5 6.5 -- -- --

7 Nutuvukti Lake tributary 6-16-94 6.9 1.9 0.6 <0.5 0.3 6.0 -- -- --

8 Kobuk River above 

Lower Kobuk Canyon 8-13-79 26 2.9 0.7 0.9 0.3 14 0.1 2.1 82

9 Beaver Pond tributary 6-17-94 32 5.4 1.3 0.6 0.2 8.5 -- -- --

10 Norutak Hills tributary 6-17-94 17 5.5 2.0 <0.5 0.2 14 -- -- --

11 Reed River at mouth 8-15-79

6-18-94

17

13

1.9

2.0

0.9

0.73

0.7

0.7

0.1

0.2

13

8.0

0.2

--

2.7

--

55

--

13 Beaver Creek 6-18-94 15 2.2 0.55 <0.5 <0.1 10 -- -- --

15 Tributary near Bear Island 6-19-94 13 6.2 2.0 <0.5 <0.2 4.5 -- -- --

16 Akpelik Creek 6-19-94 6.2 2.2 1.2 <0.5 <0.1 3.0 -- -- --

19 Pah River near mouth 8-17-79 11 2.9 2.1 0.2 0.5 6.4 0.1 6.1 5.1

23 Kogoluktuk River 

near mouth 8-19-79 29 4.0 0.9 1.0 0.3 26 0.1 2.9 104

24 Kobuk River above Kobuk 8-24-79 27 3.7 0.8 0.7 0.2 23 0.1 3.4 95

25 Ruby Creek at Bornite 8-21-79 37 6.2 0.5 <0.1 0.4 17 0.1 3.0 130

31 Kobuk River below 

Jade Creek 8-28-79 29 4.5 0.50 0.3 0.3 15 0.1 2.5 86

34 Kavet Creek at mouth 8-29-79 40 4.8 1.6 0.3 0.5 4.5 0.1 6.4 128

35 Salmon River above 

Kitlik River 8-23-79 33 7.6 0.7 0.1 0.3 51 0.1 2.7 136

36 Kitlik River near Kiana 8-23-79 7.4 1.4 0.5 <0.1 0.1 11 0.1 2.6 29

WATER-QUALITY MONITORING NETWORK

Factors to be used in designing a water-quality 

monitoring network for the Kobuk River Basin and for 

KVNP and GANPP include the optimal number and 

placement of sites, types of constituents to sample, 

frequency of sampling, time of sampling, and cost. 

The latter factor directly affects the number of sampling sites that can be included in the network. It 

is unknown when and how much funding will be 

available for water-quality monitoring of the Kobuk 

River Basin in the two national parks and thus how 

many sites are possible; however, the primary goal 

of this study was to identify potential monitoring sites. 

The following guidelines were used: (1) sites and 

corresponding watershed area should be entirely 

within either KVNP or GANPP, (2) sites should 

represent the different physical characteristics found 

in the parks, (3) a spatial distribution should be obtained, 

and (4) specific sites requested by the National Park 

Service should be included in the monitoring network.

Classification Analysis

Cluster analysis was developed as a means of classifying objects into homogeneous groups on the basis of 

some measure or set of measures describing the objects. 
17

SULFATE PLUS CHLORIDE

CALCIUM PLUS MAGNESIUM

SODIUM PLUS POTASSIUM

PERCENT

PERCENT

PERCENT

SULFATE

MAGNESIUM

CALCIUM CHLORIDE, FLUORIDE, NO2 + NO3

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100

80

60

40

20

0

100 100

80 80

60 60

40 40

20 20

0 100

80

60

40

20

0

0

100

6

80

0

20

40

0

ALKALINITY

Figure 14. Water chemistry in samples 

collected basinwide on reconnaissance 

trip of 1979. 

Classification analysis is a multivariate statistical technique that separates data into groups or clusters that are 

both homogeneous and distinct from other groups 

(Davis, 1986). For this study, the classification analysis 

was done using Geographic Information Systems 

(GIS) techniques. In using GIS techniques, different 

coverages are stacked on top of each other and then an 

isocluster function is used to identify the clusters. The 

isocluster function uses a k-means clustering approach, 

in which k points characterized by m variables are 

designated (either by the user or arbitrarily by the program) as initial centroids. The number of observations 

are calculated, and the closest or most similar observations are clustered with the nearest centroids. New 

centroids are then calculated and the process iterates 

exactly like a hierarchical procedure. This clustering 

method divides candidate basins into groups by maximizing the between-cluster variation and minimizing 

the within-cluster variation. 

Groupings of clusters were evaluated to 

determine which one provided the most practical 

and common-sense environmental framework. To 

determine whether the clusters were good in terms 

of their separability, a dendrogram was constructed. 

Dendrograms order the clusters relative to each other 

using the multidimensional distance separating the 

classes in attribute space. A good cluster should have 

little overlap between the clusters in multivariate 

space. If the dendrogram indicates clusters with identical means, the clusters are often combined. After any 

classes are combined, the cells were classified as to 

their “most likely cluster.” The Arc/INFO function 

“classprob” calculates for each cell the probability 

of the cell belonging to each cluster. The cell is then 

assigned to the class with the highest probability.

The following GIS coverages composed the 

initial data set:

•Soil and Carbon Regions, figure 8 (National 

Resources Conservation Service, 2000): The carbon 

map indicates areas where carbon is stored. Due to 

climate warming, the permafrost will melt and the 

active layer will grow. Additional dissolved organic 

carbon will likely enter streams and rivers.

•Permafrost Regions, figure 7 (Ferrians, 1965): 

Permafrost acts as a barrier to infiltration. However, 

if the permafrost melts, infiltration will increase, 

resulting in a higher ground-water component. 

Changes in runoff characteristics would affect water 

quality.
18

•Geology, figure 6 ××(Silbererling and others, 1994): 

Water-quality characteristics of surface water are 

strongly affected by the type and age of rock.

•Vegetation (Land Cover) figure 5 (Alaska Geospatial Data Clearinghouse, 1998): Land cover influences 

a number of hydrologic factors, such as snow accumulation, soil moisture depletion, surface runoff, infiltration, and erosion. Different types of vegetation have 

different rates of interception. The amount of interception is important because it determines the amount 

of particles and dissolved carbon that is washed off 

the leaves, thus affecting soil and water chemistry.

•Physiographic Regions, figure 4 (Wahrhaftig, C., 

1965): These regions represent the topographic 

features of the region. For example, topographic 

regions that are steep basins will most likely have 

more runoff than regions that are flat.

•Precipitation Regions, figure 2 (Jones and Fahl, 

1994): The amount of precipitation affects the amount 

of runoff from a particular basin. Loads of particular 

water-quality constituents are dependent on the 

amount of runoff.

The variables for each GIS coverage were 

“scaled” to give each coverage equal weight (table 11). 

For example, precipitation regions were assigned a 

value of 1, 2, or 3, representing 15–20, 20–30, and 

30–40 inches (low to high) of precipitation respectively. Although somewhat crude, the variables can be 

considered continuous. The data are not normal and 

various transformations of the data could not correct 

this problem. However, the cluster analysis was still 

done to help serve as a visualization tool in combining 

all the information from the different GIS coverages.

A principal component analysis (PCA) was run 

on the GIS data before the cluster analysis. The purpose of the PCA was to transform the data into a new 

set of variables. These new variables are not correlated 

with each other and explain a percentage of the variance of the data. The first principal component explains 

most of the variance of the data. Each succeeding 

principal component explains more of the remaining 

variance. Based on the PCA, the precipitation and 

permafrost coverages did not account for a significant 

amount of the variance, probably because these 

two coverages (fig. 2 and fig. 7) overlap with (or are 

similar to) the physiographic-regions coverage (fig. 4). 

Thus, the PCA helped eliminate the redundancy of 

data, and it was not necessary to use the precipitation 

and permafrost coverages in the cluster analysis. 

Table 11. Values assigned to different units of geographic 

information system coverages

[lb/ft2, pounds per square foot; >, greater than]

Value Represents Remarks

CARBON (figure 8)

1 No carbon present Lowest carbon

2 0 to 2 lb/ft2

3 2 to 6.5 lb/ft2

4 6.5 to 13 lb/ft2

5 > 13 lb/ft2 Highest carbon

GEOLOGY (figure 6)

1 Cenozoic volcanic rocks Youngest rocks

2 Mesozoic sedimentary rocks

3 Mesozoic volcanic rocks

4 Mesozoic intrusive rocks

5 Paleozoic sedimentary rocks

6 Precambrian rocks Oldest rocks

PERMAFROST (figure 7)

1 Continuous—high rugged mountains No infiltration

2 Continuous—lowland areas

3 Discontinuous—mountains

4 Discontinuous—lowlands Highest infiltration

PHYSIOGRAPHIC (figure 4)

1 High rugged mountains Steepest slope

2 Low mountains

3 Rolling hills

4 Plains Flat areas

PRECIPITATION (figure 2)

1 15–20 inches Lowest precipitation

2 20–30 inches

3 30–40 inches Highest precipitation

VEGETATION (figure 5)

1 Needleleaf Highest interception

2 Tall shrub

3 Dwarf shrub

4 Moist herbaceous Lowest interception
19

The initial cluster analysis indicated seven clusters (fig. 15). These clusters formed two major clusters 

that indicated a north-south division of the Kobuk 

River Basin (fig. 16). A comparison of the six GIS 

coverages makes the north-south division apparent. 

For example, the northern portion of the Kobuk River 

Basin consists of mountainous terrain, whereas the 

southern portion consists of plains and lowlands. The 

northern portion of the Kobuk Basin has higher precipitation and is dominated by Paleozoic sedimentary 

rocks, while the southern portion of the Kobuk Basin 

has lower precipitation and is dominated by Mesozoic 

sedimentary rocks. Thus, it is felt that the cluster analysis provided reasonable guidance when the information from all the GIS coverages was combined.

As another check on the cluster results, a limited 

comparison can be made among the water-quality data 

that have been collected on the tributaries to the Kobuk 

River (table 10). Values of silica are significantly 

higher at sites 19 and 34 on Pah River and Kavet Creek, 

located in cluster region 2, than at the sites that are 

located in cluster region 1. At sites 5, 9, 10, and 15 

on Red Bog tributary, Beaver Pond tributary, Norutak 

Hills tributary, and Bear Island tributary, respectively, 

streams that drain areas in cluster region 2, values of 

magnesium are higher than in some streams located in 

cluster region 1. 

These comparisons might be another indication 

that the stratification of the Kobuk River Basin is 

reasonable. Once a sufficient data amount has been 

collected, another technique that could be used to test 

the stratification is Multiple Discriminant Analysis 

(MDA). MDA is a procedure in which data are 

assigned a probability of being in a particular region. 

Low probabilities would indicate that the water-quality 

monitoring network should be reviewed and possibly 

revised.

Site Selection

Using the results of the cluster analysis and the 

selection criteria listed in the first paragraph of the 

“Water-Quality Monitoring Network” section as 

guides, potential water-quality sites were identified. 

The selection process consisted of identifying potential 

watersheds in the northern section of the Kobuk River 

Basin (cluster region 1) and the southern section of 

the Kobuk River Basin (cluster region 2). Once 

a potential watershed was identified, an ArcView 

extension, the Watershed Delineator, was used to compute the basin area. Use of the Watershed Delineator 

permitted a quick and accurate means of determining 

the size of the watershed upstream from the potential 

monitoring site. The corresponding basin characteristics were computed once the area was determined. 

Since factors such as access to a potential site 

and hydraulic and mixing characteristics are unknown, 

many potential sites were selected (fig. 17, table 12). 

1

4

7

DISTANCE

0

6

5

2

3

CLASS

0.7971 1.5942 2.3913 3.1883 3.9854 4.7825 5.5796 6.3767 6.1738

Figure 15. Dendrogram of the cluster regions of the Kobuk River Basin, Alaska. 
20

Kobuk Valley National Park

Gates of the Arctic National Park 

Ambler

Kobuk

Lake Selby

Kobuk

River

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

160 ̊

160 ̊

67 ̊

30'

67 ̊

00'

EXPLANATION

Cluster region 1Cluster region 2

Figure 16. Cluster regions of the Kobuk River Basin, Alaska. 
21

Kallarichuk

River

KitlikRiver

Salmon

 River

Tutuksuk

 River

East Fork 

Tutuksuk

River

Kaliguricheark River

East Fork Kaliguricheark River

Akiak Creek

Hunt River Nekakte

Creek Akillik River

NunaCreek

Nigeruk Creek

KavetCreek Tunutuk Creek

Ambler

River

Kutarlak

Creek Ivik Creek Mauneluk River Upper Re

River 

Ak

R

Angayu

Cre

Lockwood 

Creek

Kobuk Valley National Park

Gates of the Arctic National Park 

Ambler

Kobuk

Lake

Selby

Kobuk

River

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

160 ̊

160 ̊

67 ̊

30'

67 ̊

00'

Figure 17. Potential watersheds for water-quality monitoring sites in the Kobuk River Basin, Alaska. 
22

Table 12. Potential watersheds for monitoring sites in the Kobuk River Basin, Alaska[mi2, square miles; in, inches; lb, pounds; #, number]

Potential watershed

Area

(mi2)

Cluster

region

Precipitation

(in)

Slope

(degrees) Physiography1

1Physiography:R, Moderately high rugged mountains; P, Plains and lowlands; Pl, Plateaus and highlands of rolling topography and gentle slopes; L, Low mou

Geology2

2Geology: P, Paleozoic sedimentary rocks; MI, Mesozoic intrusive rocks; PR, Precambrian rocks; MS, Mesozoic sedimentary rocks; MV, Mesozoic volcanic r

Land cover3

3Land cover vegetation: D, Dwarf shrub; T, Tall and low shrub; N, Needleleaf forest; DR, dry or moist herbaceous. 4Permafrost:M, Mountainous areas underlain by continuous permafrost; L, Lowland areas underlain by continuous permafrost. 

GATES OF THE ARCTIC NATIONAL PARK AND PRESERVE

Ambler River 134 1 25 23 R P D Kutarlak Creek 32.2 1 25 24 R P T Ivik Creek 75.6 1 29 26 R P D Mauneluk River 71.1 1 30 25 R P D Upper Reed River 113 1 30 25 R MI D Reed River at mouth 364 1,2 24 14 R PR T Inyuilak Creek 45.4 1 30 23 R PR D Kaluluktok Creek 146 1 30 24 R PR D Upper Kobuk River 191 1 28 23 R P T Kichaiakaka Creek 84.7 1 24 24 R P T Akpelik Creek 34.8 2 17 16 R MS N Norutak Creek 34.8 2 17 8 P MS N Lockwood Creek 13.3 2 17 11 P MS N Unnamed Creek #1 37.8 2 17 7 P MV N Unnamed Creek #2 45.6 2 17 8 P MS N Unnamed Creek #3 22.4 2 17 11 P MS N Angayukachak Creek 24.2 2 17 15 P MS DR 

KOBUK VALLEY NATIONAL PARK AND PRESERVE

Nuna Creek 67.5 1 25 13 L P DR Akillik River 126 1 25 16 L P DR Nekakte Creek 48.2 1 25 16 L PR DR Hunt River 141 1 24 17 L P DR Akiak Creek 101 1 24 17 L PR DR Kaliguricheark River 37.6 1 25 17 L PR DR East Fork Kaliguricheark River 43.6 1 25 15 L PR DR Tutuksuk River 196 1 24 18 L PR DR East Fork Tutuksuk River 72.3 1 25 18 L PR DR Salmon River 508 1,2 22 14 L P DR Kitlik River 70.5 1 25 14 L P DR Nigeruk Creek 111 2 17 14 Pl MS N Kallarichuk River 102 2 19 24 L P DR Kavet Creek 38.0 2 17 10 Pl MS N Tunutuk Creek 35.8 2 17 4 P MS N 
23

The size of the basins ranged from 35.8 to 196 mi2

in KVNP and from 13.3 to 364 mi2 in GANPP. Most 

of the basins are located entirely in cluster region 1 

or 2, with only a few overlapping both regions. Sites in 

cluster region 1 would generally be in areas considered 

rugged and steep, having minimal soils and carbon, and 

underlain by continuous permafrost. Sites in cluster 

region 2 would generally be in areas considered plains 

or lowlands, consisting of soils with varying amounts 

of carbon, covered by needleleaf forests, and underlain 

by moderately thick to thin permafrost.

SUMMARY AND CONCLUSIONS

This report summarizes available water-quality 

and water-quantity data for the Kobuk River Basin 

and presents a method to identify future water-quality 

monitoring sites located in the Kobuk River Basin and 

within Gates of the Arctic National Park and Preserve 

and Kobuk Valley National Park. Specific findings are:

1. The average discharge of the Kobuk River 

near Kiana ranged from 10,020 to 24,960 ft3

/s 

from 1977 to 1999. Most of the flow in the 

Kobuk River occurs between late May and 

October.

2. Based on historical water-quality data, the 

water of the Kobuk River and its tributaries is 

considered a calcium to calcium-magnesiumbicarbonate type water. 

3. A statistical technique, cluster analysis, was 

used to stratify the Kobuk River Basin into two 

distinct regions based on physical characteristics of the basin such as the amount of carbon, 

vegetation (land cover), and geology. Potential 

water-quality monitoring sites were then chosen from these two regions.

4. The geographic information system (GIS) 

coverages used for this study are at a large 

scale and lack some detail. In addition, some 

of the coverages, such as permafrost and 

geology, were mapped over 30 years ago 

and may have changed. If more recent maps 

and smaller-scale maps become available, the 

cluster analysis should be redone to determine 

if there are other distinct regions in the Kobuk 

River Basin.

REFERENCES CITED

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URL agdc.usgs.gov/data/usgs/erosafo/veg/veg.html.

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sea ice and air temperatures in high latitudes: Bulletin 

of American Meteorological Society, v. 74, no. 1, 

p. 33–47.

Childers, J.M., and Kernodle, D.R., 1983, Reconnaissance 

of surface-water resources in the Kobuk River Basin, 

Alaska, 1979–90: U.S. Geological Survey WaterResources Investigations Report 83–4027, 35 p.

Davis, J.C., 1986, Statistics and data analysis in geology: 

John Wiley and Sons, New York, New York, 646 p.

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Kobuk River tributaries: Water Resource Investigation, 

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Piper, A.M., 1944, A graphic procedure in the geochemical 

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Silbererling, N.J., Jones, D.L., Monger, J.W.H., Coney, P.J., 

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in Plafker, George, and Berg, H.C., eds., The geology 

of Alaska: Geological Society of America, The geology 

of North America, v. G-1, plate 3, 1 sheet, scale 

1:7,500,000.

U.S. Department of Agriculture, 1975, Soil taxonomy—A 

basic system of soil classification for making and 

interpreting soil surveys: Soil Conservation Service, 

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U.S. Geological Survey Professional Paper 482, 51 p., 

6 plates.
U.S. Department of the Interior

U.S. Geological Survey

Hydrologic Data and a Proposed Water-Quality 

Monitoring Network for the Kobuk River Basin, 

Gates of the Arctic National Park and Preserve, 

and Kobuk Valley National Park, Alaska

Water-Resources Investigations Report 01–4141

Prepared in cooperation with the 

NATIONAL PARK SERVICE 

ALASKA
Cover photograph:

View of the Kobuk River Basin near Kiana, Alaska. (Photograph by Richard Kemnitz, U.S. Geological Survey, July 10, 1988.)