U.S. Department of the Interior

U.S. Geological Survey

Water Quality of the Tlikakila River and 

Five Major Tributaries to Lake Clark, 

Lake Clark National Park and Preserve, 

Alaska, 1999–2001

By TIMOTHY P. BRABETS

Water-Resources Investigations Report 02–4127

Prepared in cooperation with the

NATIONAL PARK SERVICE

 Anchorage, Alaska

 2002
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

CHARLES G. GROAT, DIRECTOR

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

descriptive purposes only and does not constitute 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

http://ak.water.usgs.gov
i

CONTENTS

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

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

Purpose and scope........................................................................................................................................... 4

Methods of data collection and analysis ......................................................................................................... 4

Acknowledgements......................................................................................................................................... 5

Description of study area.......................................................................................................................................... 5

Water quality of the Tlikakila River ........................................................................................................................ 6

Physical properties .......................................................................................................................................... 8

 Specific conductance................................................................................................................................... 8

 pH................................................................................................................................................................ 9

 Water temperature....................................................................................................................................... 9

 Dissolved oxygen...................................................................................................................................... 10

 Alkalinity .................................................................................................................................................. 10

 Major ions and dissolved solids................................................................................................................ 11

 Nutrients and organic carbon .................................................................................................................... 11

 Suspended sediment.................................................................................................................................. 14

Flow characteristics of the Tlikakila River ............................................................................................................ 15

Water budget of Lake Clark ................................................................................................................................... 18

Loads of selected-water quality constituents ......................................................................................................... 19

Other major tributaries to Lake Clark .................................................................................................................... 20

Summary and conclusions...................................................................................................................................... 22

References cited ..................................................................................................................................................... 23

Appendix 1. Physical properties and water-quality constituents of streamflow samples collected from the 

Tlikakila River, March 1999 through September 2000 ..................................................................... 25

Appendix 2. Physical properties and water-quality constituents of streamflow samples collected from the 

Chokotonk River, June 1999 through September 2001..................................................................... 27

Appendix 3. Physical properties and water-quality constituents of streamflow samples collected from the 

Chulitna River, June 1999 through September 2001......................................................................... 27

Appendix 4. Physical properties and water-quality constituents of streamflow samples collected from 

Currant Creek, June 1999 - September 2001..................................................................................... 28

Appendix 5. Physical properties and water-quality constituents of streamflow samples collected from the 

Kijik River, June 1999 through September 2001 .............................................................................. 28

Appendix 6. Physical properties and water-quality constituents of streamflow samples collected from the 

Tanalian River, June 1999 through September 2001......................................................................... 29

Appendix 7. Physical properties and water-quality constituents of streamflow samples collected from 

Lake Clark outlet, June 1999 through September 2001 .................................................................... 29

FIGURES

1. Map showing location of Lake Clark National Park and Preserve.............................................................. 2

2. Map showing shaded relief of the Lake Clark watershed, sampling sites, and precipitation sites.............. 3

3. Graph showing altitude of Lake Clark from May through September, 1999 - 2001................................... 6

4-6. Maps showing:

4. Mean annual precipitation regions of the Lake Clark watershed ................................................................ 7

5. Tlikakila River Basin, location of precipitation gage and streamgage, and water-quality sampling site.... 8

6. Photograph of an unnamed glacier in the upper Tlikakila River Basin....................................................... 9
ii

Figures--Contiued

7-11. Graphs showing:

7. Daily specific conductance and discharge of the Tlikakila River, May–September 2000.......................... 9

8. Water temperature of the Tlikakila River, October 1999 through September 2000 ................................. 10

9. Dissolved oxygen concentration of the Tlikakila River, July 27 through September 30, 1999 ................ 10

10. Trilinear diagram of 11 water samples of the Tlikakila River collected from March 1999 through 

September 2000......................................................................................................................................... 12

11. Relation between specific conductance and calcium concentration in 11 streamflow samples 

from the Tlikakila River, 1999–2000........................................................................................................ 13

12. Photograph of the mouth of the Tlikakila River showing a large deposition area .................................... 15

13. Landsat image of Lake Clark taken September 6, 1999, showing sediment plumes from Tlikakila 

River ....................................................................................................................................................... 16

14-21. Graphs showing:

14. Relation between instantaneous discharge and instantaneous suspended-sediment load for the 

Tlikakila River, 1999–2000 ...................................................................................................................... 17

15. Discharge hydrograph for the Tlikakila River, July 1–15, 2000 ............................................................... 17

16. Discharge hydrograph for the Tlikakila River, May through September 1999......................................... 18

17. Precipitation at Port Alsworth and upper Tlikakila River, June through September 2001 ....................... 18

18. Relation between lake altitude and outflow of Lake Clark ....................................................................... 18

19. Discharge measurements made at major tributaries to Lake Clark, June through 

September 1999–2001............................................................................................................................... 21

20. Suspended-sediment concentrations of major tributaries to Lake Clark, June through 

September 1999–2000............................................................................................................................... 21

21. Water temperature of major tributaries to Lake Clark, October 1999 through September 2001 .............. 22

TABLES

1. Morphometry of Lake Clark at 295.00 feet water-surface altitude ............................................................. 5

2. Basin characteristics of six major tributaries to Lake Clark........................................................................ 6

3. Physical properties measured in 12 water samples collected from the Tlikakila River, March 1999 

through September 2000............................................................................................................................ 10

4. Major dissolved inorganic constituents measured in 11 water samples collected from the Tlikakila 

River, March 1999 through September 2000............................................................................................. 11

5. Results of regression analysis relating concentrations of dissolved solids and major ions to specific 

conductance in 11 streamflow samples collected from the Tlikakila River, March 1999 through 

September 2000 ......................................................................................................................................... 13

6. Nutrient and organic carbon concentrations measured in 12 water samples collected from the 

Tlikakila River, March 1999 through September 2000 ............................................................................. 14

7. Suspended-sediment concentration measured in 12 water samples collected from the Tlikakila 

River, March 1999 through September 2000............................................................................................. 17

8. Water budget of Lake Clark and contribution of the Tlikakila River........................................................ 19

9. Monthly loads of selected water-quality constituents for the Tlikakila River, June through 

September 2000 ......................................................................................................................................... 20

10. Monthly loads of suspended sediment for the Tlikakila River, June through September 1999–2001...... 20

11. Ranges in discharges and selected water quality constituents for six major tributaries to 

Lake Clark, 1999–2001.............................................................................................................................. 22
iii

CONVERSION FACTORS, VERTICAL DATUM, AND WATER-QUALITY INFORMATION

Multiply by To obtain

inch (in.) 25.4 millimeter 

foot (ft) 0.3048 meter

mile (mi) 1.609 kilometer

square mile (mi2

) 2.590 square kilometer

cubic foot per second (ft3

/s) 0.02832 cubic meter per second

million gallons (Mgal) 3,785 cubic meter

ton 0.9072 megagram

acre-feet 1,233 cubic meter

In this report, temperature is reported in degrees Celsius (°C), which can be converted to degrees Fahrenheit (°F) by 

the following equation:

°F = 1.8 (°C) + 32

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 thousand micrograms per liter is equivalent to 1 milligram 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.

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.
1

Water Quality of the Tlikakila River and 

Five Major Tributaries to Lake Clark, Lake 

Clark National Park and Preserve, 

Alaska, 1999–2001

By Timothy P. Brabets

ABSTRACT

The Tlikakila River Basin, located in Lake Clark 

National Park and Preserve, drains an area of 622 

square miles. This watershed comprises about 21 percent of the Lake Clark Basin, making it one of the 

major tributaries to Lake Clark. Due to a sharp decline 

in sockeye salmon population and the lack of hydrologic data, the Tlikakila River and five other major tributaries to Lake Clark were studied during the summer 

runoff months (May through September) from 1999 

through 2001 as part of a cooperative study with the 

National Park Service.

Measurements of pH and dissolved oxygen concentrations of the Tlikakila River are within acceptable 

limits for fish survival. Water temperatures at the measurement site reach 0 o

C during the winter and this part 

of the Tlikakila River may not be suitable for fish. 

Water temperatures are within acceptable limits for fish 

during the summer months. The Tlikakila River is a 

calcium bicarbonate type water with a low buffering 

capacity. Concentrations of un-ionized ammonia are 

well below the recommended value of 0.02 mg/L for 

fish propagation. Annual transport of suspended sediment by the Tlikakila River into Lake Clark ranged 

from 0.4 to 1.5 million tons during 1999–2001. The 

fine sediment from the Tlikakila River disperses 

through the lake over the summer, affecting light transmissivity. 

Most runoff from the Tlikakila River occurs from 

mid-to-late May through September. Average discharge 

for these months during 1999–2001 was 6,600 ft3

/s. 

Total annual inflow to Lake Clark from the Tlikakila 

River ranged from 32 to 45 percent of the total inflow. 

The relatively high proportion of inflow is due to the 

presence of glaciers, which comprise 36 percent of the 

watershed.

Monthly measurements of flow, field water-quality 

parameters, alkalinity, and suspended sediment were 

collected on the remaining five tributaries to Lake 

Clark: the Chokotonk River, Currant Creek, the Kijik 

River, the Tanalian River and the Chulitna River. Similar to the Tlikakila River, pH and dissolved oxygen 

concentrations of these rivers are within acceptable 

limits for fish survival and the rivers have a low buffering capacity. Small amounts of suspended sediment are 

transported by the Kijik and Tanalian Rivers due to 

lakes acting as settling basins in their watersheds. The 

Chulitna River also transports small amounts of suspended sediment due to its flat topography and the 

presence of many lakes in the basin. Some suspended 

sediment is transported by the Chokotonk River and 

Currant Creek during the runoff season due to the presence of glaciers within their basins, but not as much as 

the Tlikakila River. The Chulitna River provides the 

most discharge into Lake Clark after the Tlikakila 

River and has the warmest water temperature of the 

major tributaries to Lake Clark. Water temperatures of 

Currant Creek and the Chokotonk River are similar to 

the Tlikakila River. The Kijik River and Tanalian River 

have similar temperatures that may be due to the presence of lakes in their basins and are characterize by 

slowly declining and rising temperatures. At all sites 

water temperature approaches 0 oC during winter 

months which may not be suitable for fish survival.

INTRODUCTION

Lake Clark National Park and Preserve is located 

in south-central/southwest Alaska (fig. 1). The park is 

approximately 6,300 mi2

 in area and straddles several 
2

0 100 MILES

0 100 KILOMENTERS

50

50

62o

58o

60o

154o 158o 156o 152o

Lake Clark

Iliamna 

Lake

Bristol Bay

Cook Inlet

Lake Clark 

National Park 

and Preserve

Kvichak River

Cook 

Inlet 

Basin

Kuskokwim 

River 

Basin

Nushagak 

River 

Basin

Location

ALASKA

Chigmit Mountains

Lake Clark

Watershed

Anchorage

Figure 1. Location of Lake Clark National Park and Preserve.

river basins. Approximately one-third of the park is 

located in the Cook Inlet Basin of south-central Alaska. 

Streams and rivers in this section of the park flow east 

into Cook Inlet. The remaining two-thirds of the park is 

located in the Kvichak, the Kuskokwim, and the Nushagak River Basins of southwest Alaska. Streams and 

rivers in the Kvichak and Nushagak River Basins flow 

southwest, eventually entering Bristol Bay. In terms of 

sockeye salmon (Oncorhynchus nerka), the Kvichak 

River Basin is one of the most productive basins in 

Alaska. Each year, millions of fish make their way up 

from Bristol Bay to spawn in the many streams and rivers located in the park.

Lake Clark National Park and Preserve was established in 1980 as part of the Alaska National Interest 

Lands Conservation Act (ANILCA). The primary purposes stated in the park’s enabling legislation include 

“...protect the watershed necessary for perpetuation of 

the red salmon fishery in Bristol Bay;...maintain unimpaired the scenic beauty and quality, including...glaciers, wild rivers, lakes, waterfalls...in their natural 

state” (Alaska National Interest Lands Conservation 

Act, 1980). The Tlikakila River, a federally designated 

Wild and Scenic River, is entirely located in Lake 

Clark National Park and Preserve. The second largest 

watershed of the Lake Clark Basin (fig. 2), the Tlikak-
3

0

0

5

5 10

10 15 20 25 MILES

15 20 25 KILOMETERS

153o 156o 155o 154o

61o

60o30'

60o

Tlikakila River Basin

Chokotonk River Basin

Currant Creek Basin

Tanalian River Basin

Kijik River Basin

Chulitna River Basin

Lake Clark

▲ Stream gage and water

 quality sampling sitePrecipitation gage

EXPLANATION

Basin boundaryWater quality sampling site

▲

Port 

Alsworth

Highest elevationLowest elevation

Figure 2. Shaded relief of the Lake Clark watershed, sampling sites, and precipitation sites.
4

ila, embodies all of the resource qualities: glaciers, rivers, waterfalls, mountain scenery, and salmon habitat, 

for which the park was established. 

Sockeye salmon, a keystone species of Lake Clark 

National Park and Preserve, are declining for unknown 

reasons. In 1996, the number of adult salmon returning 

to the Lake Clark watershed was only 2.3 percent of the 

previous eight-year average (National Park Service, 

oral commun., 1998). This low percentage of return has 

continued to the present. Changes in the water quality 

of Lake Clark or its tributaries could be a contributing 

factor to the decline. However, no water-quality or 

water-quantity data exists for the Tlikakila River. A 

basic understanding of the Lake Clark watershed is 

necessary for park managers to preserve the high quality of water resources. This includes not only Lake 

Clark, but the inflows to the lake as well. Obtaining 

knowledge of the entire watershed could lead to a better understanding of the spawning habitat of sockeye 

salmon.

Purpose and Scope

This report summarizes the results of a cooperative 

study by the National Park Service (NPS) and the U.S. 

Geological Survey (USGS) to measure the water quality and quantity of the Tlikakila River, one of the major 

tributaries to Lake Clark. The purpose of the study was 

threefold: (1) to determine if the present water-quality 

of the Tlikakila River is detrimental to sockeye salmon, 

(2) to establish a baseline water quality and water 

quantity data base for the Tlikakila River, and (3) to 

collect some flow and water-quality data from the other 

major tributaries to Lake Clark to compare with the 

data collected from the Tlikakila River. The Tlikakila 

River Basin was chosen as the main focus of the study 

because it is the largest river basin of the Lake Clark 

watershed that is located entirely within the park and it 

was felt that it is the most dominant of the six tributaries to Lake Clark due to the amount of glaciers present 

in the basin.

Methods of Data Collection and Analysis

Water-quality and flow variables in the Tlikakila 

River that can affect salmon include dissolved oxygen 

concentration, water temperature, and sediment. Other 

variables such as specific conductance or flow may not 

directly affect salmon, but are important in establishing 

a hydrologic baseline. In balancing the three objectives 

of the study, the following approach was taken for data 

collection. 

Most runoff from southwest Alaska rivers, such as 

the Tlikakila, occurs from about mid-May to early 

October. Thus, most data collection was done during 

this period. Water-quality samples were collected on a 

monthly basis during 1999 and 2000 to sample a range 

of discharges. A streamflow gaging station was established near the mouth of the Tlikakila River to monitor 

flow during the summer months (mid-May through 

September). Instruments were also installed at this site 

during 1999 and 2000 to collect some or all of the following water quality constituents on a continuous 

basis: specific conductance, pH, water temperature, 

and dissolved oxygen concentration. Daily lake elevations of Lake Clark were taken by NPS personnel at 

Port Alsworth to determine if there was some correlation between lake elevation and flow of the Tlikakila 

River.

Water samples collected from the Tlikakila River 

were analyzed for nutrients, organic carbon, major 

ions, dissolved solids, and suspended sediment. The 

field-collection and processing equipment used was 

made from Teflon, glass, or stainless steel to prevent 

sample contamination and to minimize analyte losses 

through adsorption. All sampling equipment was 

cleaned prior to use with a non phosphate laboratory 

detergent and then rinsed with distilled water and 

finally by stream water just prior to sample collection. 

Depth integrated water samples were collected across 

the river by using the equal-width-increment method 

(Edwards and Glysson, 1988) and processed onsite 

using methods and equipment described by Shelton 

(1994). Samples for organic-carbon analysis were collected separately by dipping a baked glass bottle in the 

centroid of flow. Samples to be analyzed for dissolved 

constituents were filtered either onsite or at park headquarters in Port Alsworth through 0.45-μm capsule filters. Water samples were sent to the USGS National 

Water Quality Laboratory in Lakewood, Colorado, for 

analysis using standard USGS analytical methods 

(Fishman and Friedman, 1989; Patton and Truitt, 1992; 

Fishman, 1993). Suspended-sediment samples were 

sent to the USGS Sediment Analysis Laboratory in 

Vancouver, Washington, for concentration and particlesize analysis.

A Hydrolab or Yellow Springs Instrument (YSI) 

meter was used to measure specific conductance, water 

temperature, hydrogen-ion activity (pH), and dissolved-oxygen concentration at the time of sampling. 
5

Onsite water-quality probes would be cleaned at the 

time of sampling and the field measurements would be 

compared with the water-quality probe reading to 

insure accurate readings. Adjustments to the continuous water-quality data were made if necessary to 

reflect the Hydrolab or YSI reading using methods outlined by Wagner and others (2000). Discharge measurements were made at the time of sampling using 

methods outlined by Rantz and others (1982), or by 

using an acoustic doppler current profiler (ADCP) 

manufactured by RD Instruments and following the 

guidelines outlined by Lipscomb (1995).

It was beyond the scope of this study to monitor 

the other 5 major tributaries to Lake Clark at the same 

scale as the Tlikakila River. However, at the time of the 

Tlikakila River sampling, efforts were made to visit the 

other major tributaries and the outlet of Lake Clark. At 

these sites, field water quality parameters and flow 

were measured and samples for suspended sediment 

and alkalinity were collected. Hourly water temperature data were collected at these sites at various times 

during the study. Thus, at the completion of the data 

collection phase of the study, each of these sites had 

some data that could be compared to the Tlikakila 

River data as well as each other.

After the data were collected, checked, and compiled, data analysis was undertaken. The concentrations of various water-quality constituents in the 

Tlikakila River were compared to known or published 

concentrations that are recommended for fish survival. 

A water budget of Lake Clark was developed to determine the contribution of the Tlikakila River. Loads of 

selected water-quality constituents transported by the 

Tlikakila River were computed to determine how much 

of a particular constituent enters Lake Clark. These 

techniques are explained in more detail in the following sections. Finally, the data collected from the other 

major tributaries were compared to the Tlikakila River 

data to determine similarities and differences in water 

quality among the major tributaries to Lake Clark.

Acknowledgments

The author gratefully appreciates the help of Judy 

Putera, Dan Young, and Alex Wilkens of the National 

Park Service at Port Alsworth for recording lake levels 

and assisting in field work. Special thanks to Jack Ross 

of Port Alsworth for assistance in field work and for 

sharing his knowledge of Lake Clark with the author.

Table 1. Morphometry of Lake Clark at 295.00 feet water-surface

altitude (calculations based on methods by Hakanson, 1981)

Lake characteristic Value Unit

Area 128 square miles

Volume 2.7 x 107 acre-feet

Length 41 miles

Mean depth 330 feet

Maximum depth 1,000 feet

Mean width 3.1 miles

Maximum width 4.5 miles

Shoreline 158 miles

DESCRIPTION OF STUDY AREA

Lake Clark occupies an elongated, glacially steepened depression. This glacial lake is fed primarily by 

inflow from six rivers (fig. 2): the Chokotonk, Tlikakila, Currant, Kijik, Tanalian, and Chulitna. Two hydrologic seasons characterize Lake Clark: (1) summer 

when the lake is ice-free and when most of the annual 

inflow enters the lake, and (2) winter when the lake 

and most of the inflow streams are frozen, and there is 

minimum inflow into the lake. The length of the winter 

season may equal or exceed that of the summer season.

In terms of thermal classification, Lake Clark is 

similar to a polymictic lake (Alex Wilkens, National 

Park Service, oral commun., 2002). Polymictic lakes 

such as Lake Clark undergo frequent circulation due to 

winds that are present in this region throughout the 

entire year. The morphometry of Lake Clark (table 1) 

indicates that the lake is long (41 mi), narrow (3.1 mi), 

and deep (mean depth, 330 ft). The combined flow of 

the six rivers is highly seasonal and thus the corresponding lake level altitude has a large annual variation (fig. 3).

The Lake Clark watershed (fig. 2) drains 2,942 

mi2

. In addition to the six major rivers that flow into 

Lake Clark, there are numerous small glacier-fed 

streams originating in the mountains and clearwater 

streams originating in the foothills and lowlands that 

flow into Lake Clark. The topography of the Lake 

Clark watershed ranges from relatively flat in the Chulitna River Basin to relatively steep in the other basins 

(fig. 2). For example, the mean basin slope for the 

Chulitna River Basin is 7 percent while the remaining 

basins have average slopes between 21 and 25 percent 

(table 2). Precipitation also is variable (fig. 4): the 

mean annual precipitation for the Chulitna River Basin 

is 26 inches, but increases to 80 inches for the Chokotonk River Basin (Jones and Fahl, 1994).
6

1999

2000

2001

May June July August September

304

292

294

296

298

300

302

ALTITUDE, IN FEET ABOVE MEAN SEA LEVEL

 Figure 3. Altitude of Lake Clark from May through September

1999–2000.

Bedrock geology of the Lake Clark Basin varies

from predominantly Mesozoic sedimentary rocks

(youngest age) in the Kijik, Tanalian, and Chulitna 

River Basins to predominantly cenozoic intrusive 

rocks in the Chokotonk River, Currant Creek, and 

Tlikakila River Basins (oldest age) (Nelson and others, 

1983). The Chulitna River Basin consists primarily of 

sedimentary deposits and volcanic rocks (Quaternary). 

The Kijik and Tanalian River Basins consist primarily 

of volcanic rocks of tertiary age. Proceeding up the 

basin to the more rugged lands, the Currant Creek and 

Chokotonk River Basins consist of tertiary and cretaceous rocks made up of granodiorite. The Tlikakila 

River Basin contains many areas of metamorphosed 

igneous and sedimentary rocks. The predominant rock 

feature in this basin is Cretaceous and Jurassic rocks.

Most of the Lake Clark Basin is composed of rough 

mountainous lands with no soil. Soils are found in the 

Chulitna River Basin and consist of andisols, histosols, 

and spodosols (U.S. Department of Agriculture, 1975). 

Vegetation in the Lake Clark Basin consists primarily 

of alpine tundra and tall shrub with the exception of the 

Chulitna River Basin (Alaska Geospatial Data Clearinghouse, 1998). The Chulitna River Basin consists primarily of low shrub and tall shrub.

The Tlikakila River, a designated wild and scenic 

river, begins at Summit Lake in Lake Clark Pass and 

travels through a deep narrow valley into Lake Clark 

(fig. 5). This river basin, which is the second largest 

basin of the Lake Clark watershed (table 2), drains 

about 21 percent of the Lake Clark watershed. Two distinct features of this basin are (1) the presence of glaciers in about 36 percent of the basin (figs. 5 and 6) and 

(2) the relatively high mean annual precipitation (79 

inches) compared to the other five basins in the watershed.

WATER QUALITY OF THE TLIKAKILA

RIVER

In this study a number of physical properties such 

as specific conductance, pH, water temperature, and 

dissolved oxygen; and chemical constituents such as 

major ions, nutrients, organic carbon, and suspended 

sediment were measured several times in the Tlikakila 

River during the 1999–2000 water years (appendix 1, at 

the back of the report). These data establish the first 

hydrologic data base of the Tlikakila River and also 

provide insights as to whether the concentrations or 

Table 2. Basin characteristics of six major tributaries to Lake Clark

[mi2, square miles; in., inches; ft, feet;]

Tributary Area

(mi2)

Mean basin 

slope

(percent)

Mean annual 

precipitation

(in.)

Average 

elevation

(ft)

Glaciers

(mi2)

Lakes

(mi2)

Major rock 

type Major soil type Major vegetation 

type

Chokotonk River 168 25 80 2,940 29.5 0.1 Cenozoic 

intrusive

rough mountainous landalpine tundra/tall 

shrub

Tlikakila River 622 22 79 3,640 227.3 1.8 Cenozoic 

intrusive

rough mountainous landsalpine tundra/tall 

shrub

Currant Creek 165 25 66 2,930 25.9 0.1 Cenozoic 

intrusive

rough mountainous landsalpine tundra/tall 

shrub

Kijik River 298 21 50 2,650 7.4 4 Mesozoic 

sedimentary

rough mountainous landalpine tundra/tall 

shrub

Tanalian River 205 23 52 2,670 14.6 8.8 Mesozoic 

sedimentary

rough mountainous landalpine tundra/tall 

shrub

Chulitna River 1,157 7 26 1,080 0 35.5 Mesozoic 

sedimentary

spodosols/histosols/andisolslow shrub/tall 

shrub
7

GlacierGravel barLakeStreamBasin boundary

00

5

5 10

10 15 20 25 MILES

15 20 25 KILOMETERS

Tlikakila River Basin

Chokotonk River Basin

Currant Creek Basin

Tanalian River Basin

Kijik River Basin

Chulitna River Basin

Lake Clark

EXPLANATION

25 Inches35 Inches50 Inches70 Inches80 Inches

153o 156o 155o 154o

61o

60o30'

60o

Figure 4. Mean annual precipitation regions of the Lake Clark watershed (from Jones and Fahl, 1994).
8

▲ Stream gage and water

quality sampling site

Glacier

Lake

Gravel bar

Precipitation gage

▲

EXPLANATION

Summit

Lake

Tlikakila River

Tlikakila River

Tlikakila River Basin

Lake Clark Pass

153o45' 153o

30' 153o

15' 152o 153 45' o

61o

60o45'

60o

30'

60o

24'

0

0

5

5 10

10 15 20 MILES

15 20 KILOMETERS

 Figure 5. Tlikakila River Basin, location of precipitation gage and streamgage, and water-quality sampling site. 

values of certain constituents are harmful to sockeye 

salmon.

Physical Properties

Specific Conductance

Specific conductance is a measure of the ability of 

water to conduct an electric current and is determined 

by the type and concentration of ions in solution. It is a 

readily measured property that can be used to indicate 

the dissolved-solids or ion content in water, provided a 

statistical relation can be developed between specific 

conductance and a particular ion. During the low flow 

periods of May and late September 2000, the daily specific conductance of the Tlikakila River was greater 

than the specific conductance recorded from June to 
9

Figure 6. Unnamed glacier in the upper Tlikakila River Basin (photograph by T.P. Brabets, U.S. Geological Survey)

early September (fig.7). Surface runoff is at a minimum during this time and conductance values are 

indicative of ground-water inflow. From June through 

early September, the primary runoff season, the lowest 

values of specific conductance occurred. This period 

reflects runoff from snowmelt, ice melt, and rainfall 

events that probably do not contain the same amount of 

dissolved ions as ground water and thus these components of runoff create a dilution effect. Values of specific conductance for the water samples collected in 

1999 through 2000 ranged from 31 to 117 μS/cm (table 

3, appendix1). The highest values occurred in March, 

May, September, and October, the time of low flow and 

the lowest values occurred in June, July or August, the 

period of high flow.

pH

The pH of water is a measure of its hydrogen-ion 

activity and can range from 0 (very acidic) to 14 (very 

alkaline) standard units. The pH of river water not 

affected by contamination is typically between 6.5 and 

8.0 standard units (Hem, 1985) and for fish growth and 

survival, the pH should remain in the 6.5–9.0 standard 

0

12,000

2,000

4,000

6,000

8,000

10,000

DAILY DISCHARGE, 

IN CUBIC FEET PER SECOND

May June July August September

2000

SPECIFIC CONDUCTANCE,

 IN MICROSIEMENS PER CENTIMETER

20

90

30

40

50

60

70

80

Flow

Specific Conductance

Figure 7. Daily specific conductance and discharge of 

the Tlikakila River, May-September 2000.

unit range. During 1999 and 2000, the pH of the 

Tlikakila River ranged from 7.2 to 8.1 standard units 

(table 3, appendix1), within the typical range for fish 

growth and survival.

Water Temperature

Water temperature determines the amount of oxygen water can contain when at equilibrium with the 
10

atmosphere and it also controls the metabolic rates of 

fish and their rates of growth. Sockeye salmon have 

adapted to specific spawning times and water temperatures in order that incubation and emergence occur at 

the most favorable time of the year (Kyle and Brabets, 

2001). At the streamgage site (fig. 5), water temperature remains at 0 o

C from late October to mid-April 

(fig. 8). For incubation of sockeye salmon, water temperature should be at least 2.0 o

C; thus sockeye salmon 

would probably not survive in this area of the Tlikakila 

River during this period. In April, after the river ice is 

gone, the water temperature rises quickly to between 5 

and 6 oC. As air temperature and runoff increase, water 

temperature increases to approximately 10 o

C in midMay. In June, as runoff from snowmelt and glacier ice 

enter the Tlikakila River, a general cooling trend 

begins and continues as the water temperature reaches 

near freezing temperatures for the following winter.

Dissolved Oxygen

The dissolved-oxygen concentration in a stream is 

controlled by water temperature, air temperature and 

pressure, hydraulic characteristics of the stream, photosynthetic or respiratory activity of stream biota, and the 

quantity of organic matter present. Sockeye salmon and 

other fish require well-oxygenated water at every stage 

in their life, but young fish are more susceptible to oxygen deficiencies than adult fish. Dissolved-oxygen concentrations in water samples collected from the 

Tlikakila River during the study period ranged from 

11.0 to 14.0 mg/L (table 3, appendix1). Dissolved oxygen concentrations were recorded continuously from 

July 26, 1999 to September 30, 1999 (fig. 9). During 

this period dissolved oxygen concentrations varied 

between 11.5 and 16.5 mg/L, but all concentrations 

were sufficient to support fish. 

Alkalinity

Alkalinity is a measure of the capacity of the substances dissolved in water to neutralize acid. In most 

natural waters, alkalinity is produced mainly by bicar-

 Figure 8. Water temperature of the Tlikakila River, 

 October 1999 through September 2000. 

bonate and carbonate ions (Hem, 1985), which are 

formed when carbon dioxide or carbonate rocks dissolve in water. Alkalinity concentrations (reported as 

equivalent concentrations of calcium carbonate 

(CaCO3)) for the Tlikakila River ranged from 13 to 37 

mg/L (table 3, appendix 1) with a median concentration of 18 mg/L. These alkalinity concentrations indi10

18

12

14

16

DISSOLVED OXYGEN,

IN MILLIGRAMS PER LITER

31 5 10 15 20 25 31 5 10 15 20 25

August September

Maximum

Minimum

 Figure 9. Dissolved oxygen concentration of the Tlikakila 

 River, July 27 through September 30, 1999

 Table 3. Physical properties measured in 12 water samples collected from the Tlikakila River, March 1999 through September 2000 

(station 15297970)

Constituent Minimum Maximum Mean Median

Specific conductance (microsiemens/centimeter) 31 117 61 51

pH (standard units) 7.2 8.1 7.5 7.6

Water temperature (o

C) 0.0 9.4 5.8 6.8

Dissolved oxygen (mg/L) 11.0 14.0 12.2 12.0

Alkalinity (mg/L as CaCO3) 13 37 21 18

0

12

2

4

6

8

10

AVERAGE DAILY WATER TEMPERATURE, 

IN DEGREES CELSIUS

OND

1999

J FMAMJ J

2000

A S
11

cate that water in the Tlikakila River has a low 

buffering capacity and limited availability of inorganic 

carbon. Also, given the range of pH values of the 

Tlikakila River, most of the alkalinity can be assigned 

entirely to dissolved bicarbonate (Hem, 1985).

Major ions and Dissolved Solids

During 1999–2000, 11 water samples collected 

from the Tlikakila River were analyzed for major and 

dissolved ions (appendix 1), which are primarily 

derived from soil and rock weathering. Concentrations 

generally are greatest in streams draining basins with 

rocks and soils that contain easily dissolved minerals. 

The Tlikakila River Basin is composed primarily of 

Cenozoic intrusive rocks that are not easily dissolved; 

thus dissolved solids concentrations are generally low, 

ranging from 11 to 76 mg/L, with a median concentration of 34 mg/L (table 4, appendix 1).

Calcium and magnesium are both essential elements for plants and animals. Calcium is usually the 

dominant positively charged ion in most natural waters, 

followed by magnesium (Hem, 1985). Concentrations 

ranged from 4.7 to 15 mg/L for calcium and from 0.4 to 

1.8 mg/L for magnesium with median concentrations 

of 7.2 and 0.6, respectively (table 4, appendix 1).

Sodium is present in all natural waters, but usually 

in low concentrations in rivers. Median concentration 

for this constituent was 0.7 mg/L (table 4). Potassium, 

an essential element for both plants and animals, is 

abundant in nature, but seldom occurs in high concentrations in natural waters (Hem, 1985). Median concentration for this element was 1.1 mg/L (table 4). 

Bicarbonate, which originates from dissolution of sedimentary rocks, was the dominant anion and ranged 

from 16 to 45 mg/L, with a median of 22 mg/L (table 4, 

appendix 1).

Sulfate in rivers is mostly from the weathering of 

sedimentary and igneous rocks and biochemical processes. Median concentration of this constituent in the 

Tlikakila River was 4.5 mg/L (table 4). Chloride is 

present in the Tlikakila River, but median concentration was only 0.3 mg/L. Silica is dissolved from rocks 

and soils, and concentrations most commonly determined in natural water are between 1 and 30 mg/L as 

SiO2 (Hem, 1985). Median concentration of this element in the Tlikakila River was 3.8 mg/L (table 4).

Concentrations of the major ions in milliequivalents per liter, (Drever, 1997) were plotted on a trilinear 

diagram (fig. 10). The trilinear diagram helps display 

water-chemistry data in a manner to classify the chemical composition of the water. Based on the 11 samples 

collected during this study, the water of the Tlikakila 

River would be classified as calcium bicarbonate water.

Most of the major ions measured at the Tlikakila 

River indicate a good statistical relation to specific 

conductance (fig. 11; table 5). With the exception of 

sodium and potassium, the coefficients of determination (R2) were 0.77 or greater and the regression equations were statistically valid at a significance level of 

greater than 99 percent. Thus, valid estimates of concentrations of these dissolved constituents can be calculated from the equations and measured values for 

specific conductance.

Nutrients and Organic Carbon

Nitrogen is an important water-quality constituent, 

in part because it is an important component of the protoplasm of aquatic biota. In aquatic ecosystems, nitrogen commonly occurs in three ionic forms: ammonium 

 Table 4. Major dissolved inorganic constituents measured in 11 water samples collected from the Tlikakila River, March 1999 

 through September 2000 (station 15297970) 

[all values in milligrams per liter].

Constituent Minimum Maximum Mean Median

Calcium 4.7 15 8.2 7.2

Magnesium 0.4 1.8 0.7 0.6

Sodium 0.5 2.3 -- 0.7

Potassium 0.8 1.9 1.3 1.1

Bicarbonate 16 45 28 22

Sulfate 1.9 10.5 4.8 4.5

Chloride <0.1 1.8 0.6 0.3

Fluoride <0.1 <0.1 -- <0.1

Silica 2.5 8.6 4.8 3.8

Dissolved solids 11 76 38 34
12

 100 

 80 

 60 

 40 

 20 

 0 

 100 

 0 

 20 

 40 

 60 

 80 

 100 

 100 

 0 

 20 

 40 

 60 

 80 

 100 0 

 20 

 40 

 60 

 80 

 80 

 60 

 40 

 20 

 0 100 

 80 

 60 

 40 

 20 

 0 

 20 

 40 

 60 

 80 

 100 100 

 80 

 60 

 40 

 20 

 0 

 20 

 40 

 60 

 80 

 100 100 

 80 

 60 

 40 

 20 

 0 

 0 

 0 

SULFATE

CALCIUM PLUS MAGNESIUM

PERCENT

PERCENT

CALCIUM CHLORIDE, FLUORIDE, NITRITE PLUS NITRATE

MAGNESIUM

SULFATE PLUS CHLORIDE

PERCENT

SODIUM PLUS POTASSIUM

 BICARBONATE

Figure 10. Trilinear diagram Eleven water samples of the Tlikakila River collected from March 1999 through September 2000. 

(NH4), nitrite (NO2), and nitrate (NO3). In the laboratory, ammonium is analyzed as ammonia (NH3); thus 

nitrogen concentrations are reported as total and dissolved ammonia plus organic nitrogen (often called 

Kjeldahl nitrogen), dissolved ammonia, dissolved 

nitrite plus nitrate, and dissolved nitrite. Nitrite readily 

oxidizes to nitrate in oxygenated water; therefore nitrate 

is generally more abundant than nitrite in water bodies. 
13

20 120 40 60 80 100

SPECIFIC CONDUCTANCE, IN MICROSIEMENS PER CENTIMETER

2

18

4

6

8

10

12

14

16

CALCIUM, IN MILLIGRAMS PER LITER

Lower 95% Confidence Limit

Upper 95% Confidence Limit

Calcium = 1.02 + 0.13 (specific conductance)

R2 = 0.96

S.E. = 0.50 mg/L

Figure 11. Relation between specific conductance and 

 calcium concentration in 11 streamflow samples 

from the Tlikakila River, 1999–2000.

Total ammonia plus organic nitrogen concentrations 

represent the ammonium and organic nitrogen compounds in solution and associated with colloidal material. Nitrite and nitrate are oxidized forms of inorganic 

nitrogen that together make up most of the dissolved 

nitrogen in well-aerated streams. The dissolved concentrations represent the ammonium or nitrite plus 

nitrate in solution and associated with colloidal material capable of passing through a 0.45-um pore.

All concentrations of the various nitrogen forms 

were less than 1.0 mg/L (table 6; appendix 1). Total 

nitrogen (sum of Kjeldahl nitrogen and the nitrate-plusnitrite nitrogen) ranged from 0.17 mg/L to 0.92 mg/L 

(appendix 1). Due to its toxicity to freshwater aquatic 

life, the U.S. Environmental Protection Agency 

(USEPA) (U.S. Environmental Protection Agency, 

1976) suggests a limitation of 0.02 mg/L of ammonia 

(as un-ionized ammonia, NH3) for waters to be suitable 

for fish propagation. Based on the values of ammonia, 

pH, and water temperature in the Tlikakila River the 

un-ionized ammonia, was calculated as 0.19 percent of 

dissolved ammonia (U.S. Environmental Protection 

Agency, 1976, interpolated from table 3, p. 11). Thus, 

even at the maximum concentration of dissolved 

ammonia (0.028 mg/L, table 6), the concentration of 

un-ionized ammonia is well below the recommended 

criteria for fish propagation.

Phosphorus is an essential element in the growth of 

plants and animals. It occurs as organically bound 

phosphorus or as phosphate. High concentrations of 

phosphorus in water are not considered to be toxic to 

human or aquatic life. However, its presence can stimulate the growth of algae in lakes and streams. It was 

first noted by Sawyer (1947) that nuisance algal conditions could be expected in lakes when concentrations 

of inorganic nitrogen (NH3 + NO2 + NO3 as N) as low 

as 0.3 mg/L are present in conjunction with as much as 

0.01 mg/L of phosphorus.

Phosphorus concentrations are reported as total 

phosphorus and dissolved orthophosphate. Total phosphate concentrations represent the phosphorus in solution, associated with colloidal material, and contained 

in or attached to biotic and abiotic particulate material. 

The dissolved concentrations are determined from the 

filtrate that passes through a filter with a nominal pore 

size of 0.45 μm. The orthophosphate ion, PO4, is the 

most important form of phosphorus because it is 

directly available for metabolic use by aquatic plants. 

Concentrations of total phosphorus and dissolved phosphorus were less than 1.0 mg/L for all samples collected on the Tlikakila River. 

The nitrogen and phosphorus concentrations were 

used to compute the nitrogen-phosphorus ratio. This 

ratio varies with the water, season, temperature, and 

 Table 5. Results of regression analysis relating concentrations of dissolved solids and major ions to specific conductance in 11

 streamflow samples collected from the Tlikakila River, March 1999 through September 2000 (station 15297970). 

[SC, specific conductance; all equations significant at the 99 percent level]

Constituent Regression Coefficient of 

determination

Standard Error 

(mg/L)

Calcium 1.02 + 0.13 (SC) 0.92 0.72

Magnesium -0.21 + 0.02 (SC) 0.96 0.07

Sodium -0.34 + 0.02 (SC) 0.67 0.31

Potassium 0.56 + 0.01 (SC) 0.54 0.22

Bicarbonate 7.1 + 0.32 (SC) 0.98 1.4

Sulfate -0.69 + 0.10 (SC) 0.81 0.89

Chloride -0.53 + 0.02 (SC) 0.92 0.12

Silica 0.09 + 0.08 (SC) 0.77 0.84

Dissolved solids 0.84 + 0.66 (SC) 0.83 5.7
14

geological formation, and may range from 1 or 2:1 to 

100:1. In natural waters, the ratio is often near 10:1, 

and this appears to be a good guideline for indicating 

normal conditions. The ratio of nitrogen to phosphorus 

is an indication of the potential for excess growth of 

algae. If phosphorus is considered the limiting nutrient, 

a low ratio suggests that there is sufficient phosphorus 

for algae to utilize all the available nitrogen for growth, 

and a high ratio indicates that there is not enough phosphorus for algae to use all the available nitrogen. For 

the Tlikakila River, the ratio of total nitrogen to phosphorus ranged from less than 1.0 to about 26. High 

ratios occur during low flow periods in March, May, 

and September (indicating insufficient phosphorus) and 

low ratios occur during the high runoff periods (indicating sufficient phosphorus).

Dissolved organic carbon (DOC) is commonly a 

major pool of organic matter in ecosystems. DOC is 

defined as organic carbon in the filtrate (dissolved and 

colloidal phases) that has passed through a 0.45-μm 

pore-size filter. Generally, DOC is in greater abundance 

than particulate organic carbon (POC), accounting for 

approximately 90 percent of the total organic carbon of 

most waters (Aiken and Cotsaris, 1995). In the aquatic 

system, the sources of DOC can be categorized as (1) 

allochthonous—entering the system from a terrestrial 

watershed, and (2) autochthonous—being derived from 

biota (algae, bacteria, macrophytes) growing in the 

water body.

For the Tlikakila River, all concentrations of DOC 

and POC were less than 1.0 mg/L (table 6, appendix 1). 

During high flow in summer, concentrations of POC 

were greater than DOC. These low concentrations of 

POC and DOC reflect the fact that most of the Tlikakila River Basin consists of rough mountainous lands 

with a thin soil cover. Thus, only a small amount of 

organic matter is present that can be degraded. 

Suspended Sediment

Sediment in the Tlikakila River is transported in 

suspension and as bedload. Suspended sediment consists of fine particles, usually clay or silt, that are transported in a stream while being held in suspension by 

the turbulence of flowing water. Bedload consists of 

coarse sediment, usually sands, gravels, and larger particles, that are transported on or near the streambed.

In late May, as air temperatures begin to rise above 

freezing at higher altitudes, glacial meltwater begins to 

contribute to the streamflow, and a corresponding 

increase in silt-clay concentration occurs. This causes 

the Tlikakila River to take on the turbid, milky appearance that is characteristic of glacier-fed rivers. As the 

runoff season progresses, some sediment is deposited 

at the mouth of the Tlikakila River (fig. 12), forming a 

delta that almost blocks Lake Clark from Little Lake 

Clark (fig. 13). The suspended sediment that remains in 

suspension from the Tlikakila River travels downlake 

(fig. 13) and by the end of the runoff season the plume 

has traveled almost the entire length of Lake Clark. The 

significance of this sediment plume is that it reduces 

the light transmissivity of the water column. A reduction in light transmissivity combined with other limnology factors can affect the productivity of Lake Clark.

Of the 11 samples collected for suspended sediment, 6 were analyzed for percentage of silt and clay 

(<0.063 mm) (table 7). The samples averaged 66 percent finer than 0.063 mm and thus most of the suspended load consists of silt-clay particles with some 

fine sand. A stream discharge and suspended sediment 

load relation was developed to provide information on 

 Table 6. Nutrient and organic carbon concentrations measured in 12 water samples collected from the Tlikakila River,

 March 1999 through September 2000 (station 15297970) 

[all values in mg/L; NO2 + NO3, nitrate plus nitrite, E, estimated, <, less than].

Constituent Minimum Maximum Mean Median

Nitrogen, nitrite dissolved <0.001 0.001 -- 0.001

Nitrogen, NO2+NO3 dissolved 0.065 0.818 0.274 0.163

Nitrogen, ammonia dissolved <0.002 0.028 -- 0.004

Nitrogen, ammonia + organic, total <0.10 0.27 -- <0.10

Nitrogen, ammonia + organic, dissolved <0.10 0.10 -- 0.10

Phosphorus, total 0.029 0.902 0.249 0.203

Phosphorus, dissolved E.003 <0.005 -- 0.004

Phosphorus, ortho, dissolved <0.001 0.005 -- 0.001

Dissolved organic carbon E.17 0.70 0.42 0.40

Particulate organic carbon <0.2 0.9 -- 0.2
15

the amount of suspended sediment transported for a 

particular discharge (fig. 14). Although the correlation 

between discharge and load is considered good (R2

 = 

0.92), the standard error is consider to be somewhat 

high. This relation was utilized to compute sediment 

loads for periods when only daily flow data were available.

FLOW CHARACTERISTICS OF THE

TLIKAKILA RIVER

Glaciers store an enormous amount of water in the 

form of ice. This feature alone makes any drainage 

basin containing glaciers both unique and complex. 

The release of this water is highly dependent on the 

energy supplied by solar radiation and air temperature 

(Meier, 1969). A hot summer will cause substantial 

melting and runoff, whereas a cool summer will produce much less melting and runoff.

Runoff from glacier-fed rivers is strongly influenced by the glacier behavior. For example, during a 

single year, the mass of a glacier may increase, 

decrease, or remain the same. When glacier mass 

decreases (negative mass balance), the basin will yield 

more water than a similar basin without glaciers. A 

growing glacier stores and thus withholds some water 

from the normal runoff in the stream. Even if a glacier 

is in equilibrium, most of the meltwater will be 

released during a fairly short summer season. The peak 

runoff in rivers receiving glacier meltwater occurs later 

in the year than in rivers not affected by glaciers (Meier 

and Tangborn, 1961).

The hydrograph of the Tlikakila River (USGS station number 15297970) (July 1–15, 2000) provides a 

good picture of its characteristics (fig. 15). Distinct 

diurnal fluctuations occurs as follows: the low flow of 

the day usually occurs in the early morning and the 

high flow occurs at about midday, reflecting a time lag 

between melting of snow and ice and the arrival of the 

resulting meltwater at the streamflow gaging site.

Most of the annual flow of the Tlikakila River 

occurs during June to September (fig. 16). Flow in June 

is dominated by snowmelt, and in July through August, 

by glacier ice melt and rainfall. The runoff from the 

Tlikakila River indicates some trend with the lake elevation (fig. 3); the lowest lake elevation and the lowest 

Figure 12. Mouth of the Tlikakila River showing a large deposition area (photograph by T.P. Brabets, U.S. Geological Survey. 
16

River 

plume edge

River 

plume edge

Lake Clark

outlet

Chulitna 

River Tanalian River

Kijik 

River 

Currant

Creek

Chokotonk

River Tlikakila

River

gage

▲

Port Alsworth

Figure 13. Landsat image of Lake Clark taken September 6, 1999, showing sediment plumes from the Tlikakila River.
17

 Table 7. Suspended-sediment concentrations measured in 12 water samples collected from the 

Tlikakila River, March 1999 through September 2000 (station 15297970).

[mg/L, milligrams per liter; mm, millimeter; ft3/s, cubic feet per second]

Date

Suspended sediment 

concentration

(mg/L)

Percent finer 

than.063 mm

Discharge 

(ft3/s)

Suspended 

sediment 

discharge1

(tons/day)

3-16-99 5 -- 25 0.3

5-13-99 25 -- 510 34.4

6-16-99 710 63 7,500 14,400

7-26-99 227 68 12,000 7,350

8-18-99 397 62 6,160 6,600

9-16-99 71 -- 3,070 588

10-14-99 9 -- 871 21.2

5-16-00 29 -- 950 74.4

6-20-00 676 69 3,320 6,060

7-18-00 528 70 6,440 9,180

8-31-00 318 64 3,330 2,860

9-21-00 118 -- 750 239

1

Suspended sediment discharge calculated as (0.0027)*(suspended-sediment concentration)*(discharge).

amount of flow from the Tlikakila both occurred in 

2000. Peak discharges noted in 1999 and 2000 were the 

result of relatively intense rainstorms that occurred in 

the region. In 2001, there were no intense rainstorms, 

but there was more sustained flow due to warm air temperatures.

Runoff from June 1 to September 30 during 

1999–2001 totaled 52.4 in., 28.7 in., and 65.4 in., 

respectively. Average discharge was 7,200 ft3/s, 3,900 

ft3/s, and 8,600 ft3

/s respectively (or 6,600 ft3/s averaged for the three year period). The large difference in 

runoff between the 2000 runoff season and the 1999 

10

100,000

20

50

100

200

500

1,000

2,000

5,000

10,000

20,000

50,000

INSTANTANEOUS SUSPENDED-SEDIMENT LOAD, 

IN TONS PER DAY

100 100,000 1,000 10,000

INSTANTANEOUS DISCHARGE, IN CUBIC FEET PER SECOND

Suspended sediment samples

Lower 95% Confidence Limit

Upper 95% Confidence Limit

Load = (.0004) Q1.87

R2 = 0.92

S.E. = 0.42 log units

 Figure 14. Relation between instantaneous discharge and 

 instantaneous suspended-sediment load for 

the Tlikakila River, 1999–2000.

and 2001 runoff seasons probably is due to the snowpack in the basin at the time of spring snowmelt and 

the amount of rainfall that occurred during the summer 

months. Based on snowpack data from the National 

Resource Conservation Service (U.S. Department of 

Agriculture, 1999, 2000, 2001), snowpacks near the 

Tlikakila River Basin were 29 percent below average 

in 1999, 43 percent below average in 2000, and 3 percent above average in 2001. Based on rainfall data 

from the National Weather Service (1999–2001) from 

4,000

14,000

6,000

8,000

10,000

12,000

DISCHARGE, IN CUBIC FEET PER SECOND

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

JULY 2000

 Figure 15. Discharge hydrograph for the Tlikakila River, 

July 1–15, 2000. 
18

 Figure 16. Discharge hydrograph for the Tlikakila River,

May through September 1999.

a station at Port Alsworth and from stations adjacent to 

the Tlikakila River Basin, rainfall was below average 

during 2000. Rainfall records from a gage placed in the 

upper part of the Tlikakila River Basin during 2001 

(fig. 2), indicated that more rainfall occurs in the upper 

part of the basin (fig. 4, 17).

June July August September

0

10

2

4

6

8

PRECIPITATION, IN INCHES

2001

Port Alsworth

Upper Tlikakila River

Figure 17. Precipitation at Port Alsworth and upper Tlikakila 

River, June through September, 2001.

inflow and evaporation. For Lake Clark, these variables were not considered to be significant and were 

not part of the water-budget equation. 

The water budget of a lake can provide not only 

the total amount of water that enters and exits the lake 

in a given time period, but also can provide information such as the relative contribution from the various 

input components. For Lake Clark, sufficient information was available to assess the relative contribution of 

the Tlikakila River to the Lake Clark water budget.

During 1999–2001, discharge measurements made 

at the outlet of Lake Clark indicated a good statistical 

relation (r2

 = 0.98) with the lake altitude (fig. 18). Having daily lake altitude readings and using this statistical 

relation allowed the calculation of daily outflow from 

Lake Clark. The change in storage could be calculated 

by using the lake elevation data and the area of the lake 

surface (128 mi2). This assumed that the lake area does 

not change significantly with lake elevation.

296 304 298 300 302

LAKE ALTITUDE, IN FEET ABOVE SEA LEVEL

30,000

10,000

15,000

20,000

25,000

OUTFLOW, IN CUBIC FEET PER SECOND

ADCP Measurement

Lower 95% Confidence Limits

Upper 95% Confidence Limits

5,000

Outflow = 3620 (Altitude - 295) + 3050

R2 = 0.98

S.E. = 785 ft3/s

 Figure 18. Relation between lake altitude and outflow of Lake Clark. 

WATER BUDGET OF LAKE CLARK

The water budget of a lake, in its simplest terms, is 

the amount of water into and out of the lake. Mathematically, the relation is: 

I - O = S

where:

I = Inflow

O = Outflow

S = change in storage

In different regions, the water budget equation will 

also account for other variables such as ground water 

Knowing the outflow and change in storage, the 

total inflow was calculated. Comparing the discharge 

of the Tlikakila River with the total amount of inflow 

indicated the relative contribution of the Tlikakila 

River to the water budget of Lake Clark. Results of the 

water-balance analysis (table 8) indicated that for the 

runoff from June through September 1999 there was a 

total of 4.24 million acre feet of inflow to Lake Clark 

with the Tlikakila River accounting for 1.74 million 

acre feet or 41 percent. In 2000, there was a total inflow 

DAILY MEAN DISCHARGE, 

IN CUBIC FEET PER SECOND

May June July August September

1999

2000

2001

0

20,000

5,000

10,000

15,000
19

into Lake Clark of 3.01 million acre feet with the 

Tlikakila River accounting for 0.95 million acre feet or 

32 percent. In 2001, total inflow to Lake Clark was 

4.65 million acre-feet with the Tlikakila accounting for 

2.09 million acre feet or 45 percent. Thus, although the 

Tlikakila River Basin comprises only 21 percent of the 

Lake Clark watershed, it provides a substantially larger 

fraction of the total inflow to Lake Clark.

LOADS OF SELECTED WATER-QUALITY 

CONSTITUENTS

Analysis of the water-quality samples collected on 

the Tlikakila River for dissolved constituents indicated 

good correlation between specific conductance and the 

major dissolved ions (table 5). Using the regression 

equation developed for each constituent together with 

the continuous specific conductance collected on the 

Tlikakila River in 2000, loads of these constituents 

were computed as follows:

1) Using the average specific conductance for the 

day, the average concentration of each dissolved element was determined using the regression equation for 

the respective constituent (table 5).

2) Using the daily discharge and average concentration of the specific dissolved constituent, the daily 

load was computed using the equation:

L = (Q)(C)(0.0027)

where:

L = daily load in tons

Q = daily mean discharge (ft3/s)

C = daily mean concentration (mg/L)

.0027 = unit conversion factor

Loads of the dissolved major ions from June 

through September 2000 ranged from 419 tons for 

chloride to 27,000 tons for bicarbonate (table 9). Bicarbonate loads constitute the greatest loads every month, 

followed by calcium, silica, and sulfate. The greatest 

loads of these constituents were transported in July, the 

month of maximum discharge.

Daily suspended-sediment loads for the Tlikakila 

River were calculated using the minimum variance 

unbiased estimator (MVUE) or Bradu-Mundlak estimator as outlined by Cohn and others (1989). This 

technique uses the relation between the instantaneous 

discharge and instantaneous suspended-sediment load 

(fig. 14) and the continuous daily discharge and corrects the relation between the instantaneous values for 

the daily values. Also, because the equation relating 

suspended-sediment load and discharge was based on 

the logarithm of discharge, a bias correction factor is 

applied.

Using the MVUE technique, monthly suspendedsediment loads from June through September 

1999–2001 were determined for the Tlikakila River 

 Table 8. Water budget of Lake Clark and contribution of the Tlikakila River 

[values in million acre-feet, values are rounded]

Month Inflow to Lake Clark Outflow from Lake 

Clark

Change in storage of 

Lake Clark Tlikakila contribution Percent of inflow from Tlikakila River

1999

June 1.17 0.78 0.39 0.43 37

July 1.19 1.19 0 0.62 55

August 1.12 1.18 -0.06 0.49 43

September 0.76 0.86 -0.10 0.20 27

Total 4.24 1.74 41

2000

June 0.62 0.44 0.18 0.23 37

July 1.04 0.92 0.12 0.38 36

August 0.79 0.88 -0.09 0.27 34

September 0.56 0.61 -0.05 0.8 14

Total 3.01 0.95 32

2001

June 1.53 1.00 0.53 0.53 35

July 1.43 1.49 -0.06 0.60 42

August 1.09 1.26 -0.17 0.58 54

September 0.59 0.80 -0.20 0.37 62

Total 4.65 2.09 45
20

 Table 10. Monthly loads of suspended sediment for the Tlikakila River, June through September 1999-2001

(station 15297970)

[values in million tons]

Water Year June July August September Total

(rounded)

1999 0.25 0.45 0.36 0.07 1.10

2000 0.08 0.20 0.12 0.01 0.04

2001 0.38 0.42 0.41 0.24 1.50

Average 1.00

(table 10). Due to the relatively large confidence limits 

of the relation between discharge and suspended sediment (fig. 14), the estimates of the monthly suspendedsediment loads have a large variation. Because suspended-sediment load is highly dependent on the 

amount of flow, more than twice as much suspended 

sediment was transported during the 1999 and 2001 

runoff seasons (1.1 and 1.5 million tons respectively) 

than during the 2000 runoff season (0.4 million tons). 

Most suspended-sediment load is transported during 

July and August (the time of maximum flow) for all 

three years.

OTHER MAJOR TRIBUTARIES TO

LAKE CLARK

Some flow and water-quality data were collected 

during the study from the remaining five tributaries 

and at the outlet of Lake Clark (appendix 2–7, at the 

back of the report). Flow data consisted of monthly 

miscellaneous measurements during the open-water 

season from June through September. Water-quality 

data consisted of field determinations (specific conductance, pH, water temperature, and dissolved oxygen), 

alkalinity, and suspended sediment. At all locations, 

continuous water-temperature data were collected periodically.

Monthly discharge measurements (fig. 19, table 

11) help define the relative contribution of inflow from 

each tributary. Each monthly set of measurements usually took 2–3 days to complete and represent only that 

one short period of the month. Since there are daily 

fluctuations in discharge at all the major tributaries 

during a particular month, the relative contribution of 

discharge from each tributary could change within the 

month.

During the study period, the monthly discharge 

measurements indicated that the Chulitna River generally contributed the second highest flow (after the 

Tlikakila) to Lake Clark, with the exception of two 

times when it provided the greatest discharge to Lake 

Clark or once when the Tanalian River provided the 

second highest inflow. Several times, discharges for the 

Chokotonk River and Currant Creek, two basins about 

the same size and with about the same amount of glacier cover (table 2) were almost equal.

In terms of water quality, the range of specific conductance, pH, dissolved oxygen, and alkalinity among 

the other tributaries was similar (table 11) and would 

not be detrimental to fish. Concentrations of alkalinity 

indicate that the other tributaries have a low buffering 

capacity similar to the Tlikakila River. Suspended-sediment concentrations were greatest from the Tlikakila 

and the other two glacier dominated streams—the 

Chokotonk River and Currant Creek (fig. 20). The 

 Table 9. Monthly loads of selected water-quality constituents for the Tlikakila River,

 June through September 2000 (station 15297970) 

[values in tons, total values rounded]

Constituent June July August September Total

Calcium 1,900 2,900 2,200 857 7,860

Magnesium 215 294 222 104 835

Sodium 230 308 234 116 888

Potassium 361 547 398 139 1,400

Bicarbonate 6,800 10,100 7,400 2,700 27,000

Sulfate 1,200 1,700 1,200 557 4,700

Chloride 113 130 105 71 419

Silica 1,300 1,800 1,400 574 5,100

Dissolved Solids 9,600 13,700 10,200 4,200 37,700
21

June 16-17 July 19-22 August 16-18 September 13-16

0

DISCHARGE, IN CUBIC FEET PER SECOND

1999

Chokotonk

Chulitna

Currant

Kijik

Tanalian

Tlikakila

14,000

2,000

4,000

6,000

8,000

10,000

12,000

0

7,000

1,000

2,000

3,000

4,000

5,000

6,000

DISCHARGE, IN CUBIC FEET PER SECOND

June 19-21 July 18-20 August 28-31 September 19-22

2000

Chokotonk

Chulitna

Currant

Kijik

Tanalian

Tlikakila

0

12,000

2,000

4,000

6,000

8,000

10,000

DISCHARGE, IN CUBIC FEET PER SECOND

June 4-5 July 9-10 August 20-22 September 24-25

Chokotonk

Chulitna

Currant

Kijik

Tanalian

Tlikakila

2001

Figure 19. Discharge measurements made at major tribu-

 taries to Lake Clark, June through September 1999–2001.

other tributaries contribute relatively small amounts of 

sediment, probably because lakes in their basins trap 

sediments (Tanalian and Kijik River Basins), or rela0

800

200

400

600

SUSPENDED SEDIMENT, IN MILLIGRAMS PER LITER

June 15-17 July 19-22 August 16-18 September 13-16

1999

Chokotonk

Chulitna

Currant

Kijik

Tanalian

Tlikakila

2000

June 19-21 July 18-20 August 28-31 September 19-22

0

700

100

200

300

400

500

600

SUSPENDED SEDIMENT, IN MILLIGRAMS PER LITER

Chokotonk

Chulitna

Currant

Kijik

Tanalian

Tlikakila

 Figure 20. Suspended-sediment concentrations of major

 tributaries to Lake Clark, June through

September 1999–2000.

tively flat basin topography, and the presence of many 

lakes within the basin that act as settling basins (Chulitna River Basin).

Continuous water-temperature data from the major 

tributaries provide insights into the characteristics of 

each river (fig. 21). The Chulitna River provides the 

warmest water to Lake Clark. From late-June to midAugust, water temperatures are near or above 14oC. In 

late August, temperatures decline rapidly. For the outlet of Lake Clark and the two rivers that have large 

lakes located in their watersheds, the Kijik River and 

the Tanalian River, the warmest temperatures can 

exceed 13o

C (fig. 21). However, there is a gradual 

warming and cooling of these rivers due to the lake 

affect. During the winter, temperatures may reach 0o

C 

(unsuitable for fish), but for only relatively short peri-
22

 Table 11. Ranges in discharges and selected water-quality constituents for six major tributaries to Lake Clark, 1999–2001 

[ft3/s, cubic feet per second, mg/L, milligrams per liter, μs/cm, microsiemens per centimeter, oC, degrees Celsius]

Tributary Discharge

(ft3

/s)

Specific 

conductance

(μs/cm)

pH

Water 

temperature

(

o

C)

Dissolved 

oxygen

(mg/L)

Alkalinity

(mg/L as 

CaCo3)

Suspended 

sediment

(mg/L)

Chokotonk River 258–2,190 28–74 7.0–8.2 0.0–10.0 11.3–14.3 11–24 9–211

Tlikakila River 25–12,000 31–117 7.2–8.1 0–9.4 11–14 13–37 5–710

Currant Creek 279–2,760 36–74 6.9–7.6 1.7–7.5 11.1–14.9 11–20 3–282

Kijik River 432–3,000 70–88 7.0–7.8 3.5–12.5 9.4–13.7 24–28 2–123

Tanalian River 179–5,920 44–54 7.0–7.8 5.5–13.5 10.1–13.8 10–13 1–5

Chulitna River 1,320–7,420 53–85 7.0–7.8 1.0–14.5 10.0–13.2 21–36 4–9

Lake Clark outlet 8,530–23,800 55–62 7.0–7.9 4.5–11.5 10.3–14.1 20–21 1–5

No Record

0

20

5

10

15

0

14

2

4

6

8

10

12

WATER TEMPERATURE, IN DEGREES CELSIUS

Kijik River

Tanalian River

Lake Clark outlet

(station 15297990)

(station 15298010)

(station 15299000)

Chulitna River

(station 15298050)

0

12

2

4

6

8

10

OND

1999

J FMAMJ J ASOND

2000

J FMAMJ J A S

2001

Chokotonk River

Tlikakila River

Currant Creek

 Figure 21. Water temperature of major tributaries to

 Lake Clark, October 1999 through September 2001.

ods. The three glacier streams, the Chokotonk River,

Currant Creek, and the Tlikakila River, have the coldest

water temperatures. Temperatures at these streams

reflect glacier melt and the warmest temperatures reach 

about 10o

C. Temperatures rapidly rise in April and rapidly fall in September and October.

SUMMARY AND CONCLUSIONS

The Tlikakila River Basin, located in Lake Clark 

National Park and Preserve, drains an area of 622 mi2. 

This watershed comprises about 21 percent of the Lake 

Clark Basin, making it one of the major tributaries to 

Lake Clark. Due to a sharp decline in sockeye salmon 

population and the lack of hydrologic data, the Tlikakila River and five other major tributaries to Lake Clark 

were studied during the summer runoff months (May 

through September) from 1999 through 2001 as part of 

a cooperative study with the National Park Service. 

Major findings are:

• Field measurements of dissolved oxygen and pH 

of the Tlikakila River were within acceptable levels for 

fish survival. The highest measurements of specific 

conductance occur during low-flow periods and field 

alkalinity concentrations indicate a low buffering 

capacity of the river.

• Water temperature of the Tlikakila River at the 

measurement site is 0oC from late October to midApril, which is not suitable for fish at this location. 

After the river ice is gone, water temperature rises 

quickly to between 5 and 6oC. As air temperature and 

runoff increases, water temperature increases to 

approximately 10oC in mid-May. As runoff from snowmelt and glacier ice melt enter the Tlikakila, a general 

cooling trend takes place to the end of September.

• The ionic composition of water of the Tlikakila 

River is a calcium bicarbonate water type. Values of 

un-ionized ammonia are well below the value of 0.02 

mg/L recommended by the USEPA for fish propagation. The nitrogen to phosphorus ratio varies from less 

than 1 during high flow periods to about 25 during low 

flow periods. Concentrations of dissolved organic carbon and particulate organic carbon were less than 1.0 
23

mg/L, reflecting the fact that most of the Tlikakila 

River Basin consists of rough mountainous lands with 

a thin soil cover.

• The Tlikakila River is the major contributor of 

suspended sediment to Lake Clark. During the three 

years of study, the Tlikakila River transported 1.1, 0.4, 

and 1.5 million tons respectively of suspended sediment to Lake Clark. Most of the suspended sediment 

consists of silt and clay particles that are dispersed 

throughout the entire lake, affecting light transmissivity.

• Most of the runoff from the Tlikakila River 

occurs from mid-May through September. Average 

flow during 1999 - 2001 was 6,600 ft3/s. Total annual 

inflow to Lake Clark from the Tlikakila River ranged 

from 32 to 45 percent of the total inflow. The relatively 

high proportion of inflow is due to the presence of glaciers, which comprise 36 percent of the watershed.

• In addition to the Tlikakila River, there are five 

other major tributaries to Lake Clark - the Chokotonk, 

Chulitna, Kijik, and Tanalian Rivers, and Currant 

Creek. The Chulitna River, which drains the largest 

basin in the Lake Clark watershed, generally had the 

second highest discharges during the study period, 

although the Tanalian River had higher measured discharges on two occasions. Currant Creek and the 

Chokotonk River, which have glaciers in a portion of 

their basins, transport some suspended sediment, 

although considerably less than the amounts transported by the Tlikakila River. The Chulitna River, 

which has a relatively flat slope, and the Kijik and 

Tanalian Rivers, which have large lakes located in their 

basins, generally transport only small amounts of suspended sediment. The Chulitna River has the warmest 

water temperature of the major tributaries to Lake 

Clark. The Kijik River and Tanalian River have similar 

temperature ranges that may be due to the presence of 

lakes in their basins and are characterized by relatively, 

slowly declining and rising temperatures. Water temperatures of Currant Creek and the Chokotonk River 

are similar to the Tlikakila River and have the coldest 

temperatures due to glacier ice melt. These rivers are 

characterized by rapidly rising and falling temperatures.

REFERENCES CITED

Aiken, G., and Cotsaris, E., 1995, Soil and hydrology—Their

effect on NOM: American Water Works Association,

January, p. 36-45.

Alaska Geospatial Data Clearinghouse, 1998, Preliminary

vegetation classes: accessed June 2001 at URL

http://agdc.usgs.com/data/usgs/erosafo/veg/veg/html

Alaska National Interest Lands Conservation Act (ANILCA),

1980, 16 U.S.C. 3101 et seq (1988), Dec. 2 1980, Stat.

2371, Pub. L. 96-487.

Cohn, T.A., DeLong, L.L., Gilroy, E.J., Hirsch, R.M., and

Wells, D.K., 1989, Estimating constituent loads: Water

Resources Research, v. 25, no. 5, p. 937-942.

Drever, J.I., 1997, The geochemistry of natural waters-surface and groundwater environments: Upper Saddle

River, New Jersey, Prentice Hall, 438 p.

Edwards, T.K., and Glysson, G.D., 1988, Field methods for

measurement of fluvial sediment: U.S. Geological Survey Open-File Report 86-531, 118 p.

Fishman, M.J., ed., 1993, Methods of analysis by the U.S.

Geological Survey National Water Quality Laboratory—Determination of inorganic and organic constituents in water and fluvial sediments: U.S. Geological

Survey Open-File report 93-125, 217 p.

Fishman, M.J., and Friedman, L.C., eds., 1989, Methods for

determination of inorganic substances in water and fluvial sediments: U.S. Geological Survey Techniques of

Water-Resources Investigations, book 5, chap. A1,

545 p.

Hakanson, Lars, 1981, A manual of lake morphology: New

York, Springer-Verlag, 78 p.

Hem, J.D., 1985, Study and interpretation of the chemical

characteristics of natural water: U.S. Geological Survey

Water-Supply Paper 2254, 263 p.

Jones, S.H., and Fahl, C.B., 1994, Magnitude and frequency

of floods in Alaska and conterminuous basins of Canada: U.S. Geological Survey Water-Resources Investigations report 93-4179, 122 p.

Kyle, R.E., and Brabets, T.P., 2001, Water temperature of

streams in the Cook Inlet Basin, Alaska, and implications of climate change: U.S. Geological Survey WaterResources Investigations Report 01-4109, 24 p.

Lipscomb, S.W., 1995, Quality assurance plan for discharge

measurements using broadband acoustic Doppler current profilers: U.S. Geological Survey Open-File Report

95-701, 12 p.

Meier, M.F., 1969, Glaciers and water supply: Journal of the

American Water Works Association, v. 61, no. 1,

p. 8–12.

Meier, M.F, and Tangborn, W.V., 1961, Distinctive characteristics of glacier runoff: U.S. Geological Survey Professional Paper 424-B, p. 14-16.

National Climate Data Center, 2000,

http://www.ncdc.noaa.gov, accessed October 2000.

Nelson, W.H., Carlson, C., and Case, J.E., 1983, Geologic

map of the Lake Clark quadrangle, Alaska: U.S. Geological Survey Map MF-1114-A, 1 plate.
24

Patton, C.J., and Truitt, E.P., 1992, Methods of analysis by the

U.S. Geological Survey National Water-Quality Laboratory—Determination of total phosphorus by a Kjeldahl

digestion method and an automated colorimetric finish

that includes dialysis: U.S. Geological Survey OpenFile Report 92-146, 39 p.

Rantz, S.E., and others, 1982, Measurement and computation

of streamflow, Volume 1. Measurement of discharge:

U.S. Geological Survey Water-Supply Paper 2175,

631 p.

Sawyer, C.N., 1947, Fertilization of lakes by agriculturalurban drainage: Journal of New England Water Works

Association, v. 61, p. 109-127.

Shelton, L.R., 1994, Field guide for collecting and processing

stream-water samples for the National Water-Quality

Assessment Program: U.S. Geological Survey OpenFile Report 94-455, 42 p.

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

basic system of soil classification for making and interpreting soil surveys: Soil Conservation Service, U.S.

Department of Agriculture Handbook 436, 754 p.

U.S. Department of Agriculture, Natural Resource Conservation Service, 1999-2001, Alaska Annual Data Summaries.

U.S. Environmental Protection Agency, 1976, Quality criteria for water: U.S. Environmental Protection Agency,

Washington, D.C., 256 p.

Wagner, R.J., Mattraw, H.C., Ritz, G.F., and Smith, B.A.,

2000, Guidelines and standard procedures for continuous water-quality monitors—Site selection, field operation, calibration, record computation, and reporting:

U.S. Geological Survey Water-Resources Investigations

Report 00-4252, 60 p.
25

Appendix 1. Physical properties and water-quality constituents of streamflow samples collected from the Tlikakila River, 

March 1999 through September 2000 (USGS station number 15297970) 

[ft3/s, cubic feet per second; μs/cm, microsiemens per centimeter; oC, degrees Celsius; mg/L, milligrams per liter; --, no data; E, estimated]

Date 

(mm-dd-yy) Time Discharge

(ft3/s)

Specific 

conductance

(μs/cm)

pH

Water 

temperature

(

oC)

Dissolved 

oxygen

(mg/L)

 Calcium

(mg/L)

Magnesium

(mg/L)

3-16-99 1700 25 117 7.5 0.0 11.8 15.0 1.76

5-13-99 1417 510 89 7.6 9.0 11.7 12.4 1.29

6-16-99 1130 7,500 40 8.1 6.0 12.2 5.44 0.46

7-26-99 1730 12,000 31 7.6 7.0 11.3 4.66 0.37

8-18-99 1610 6,160 32 7.4 7.0 11.7 5.05 0.38

9-16-99 1430 3,070 55 7.2 6.0 13.3 7.15 0.57

10-14-99 1115 871 91 7.3 0.0 11.6 -- --

5-16-00 1815 950 76 7.6 9.4 13.6 11.3 1.06

6-20-00 1645 3,320 48 7.5 7.5 11.0 7.30 0.59

7-18-00 1315 6,440 37 7.6 5.0 14.0 5.67 0.41

8-31-00 1345 3,330 44 7.5 5.0 13.0 6.06 0.44

9-21-00 1620 750 71 7.5 8.0 11.0 9.67 0.84

Date Time Sodium 

(mg/L)

Potassium 

(mg/L)

Bicarbonate 

(mg/L as 

HCO3)

Alkalinity 

(mg/L as 

CaCO3)

Sulfate 

(mg/L)

Chloride 

(mg/L)

Fluoride 

(mg/L)

Silica 

(mg/L)

3-16-99 1700 2.3 1.9 45 37 10.5 1.8 <0.1 8.6

5-13-99 1417 1.9 1.8 35 29 7.4 1.4 <0.1 7.9

6-16-99 1130 0.7 0.8 22 17 3.3 0.3 <0.1 3.5

7-26-99 1730 0.6 1.1 16 13 2.3 <0.1 <0.1 2.5

8-18-99 1610 0.5 0.9 17 14 1.9 0.2 <0.1 2.5

9-16-99 1430 0.8 1.1 22 18 4.5 <0.3 <0.1 3.8

10-14-99 1115 -- -- 36 30 -- -- -- --

5-16-00 1815 1.7 1.9 34 26 7.2 1.1 <0.1 7.9

6-20-00 1645 1.0 1.5 23 18 4.5 0.4 <0.1 4.8

7-18-00 1315 0.6 1.0 20 15 2.6 0.3 <0.1 2.8

8-31-00 1345 0.6 1.0 21 16 2.6 0.3 <0.1 2.8

9-21-00 1620 1.3 1.5 30 23 7.1 0.7 0.2 5.3

Date Time

Solids residue 

at 180 oC 

dissolved 

(mg/L)

Nitrogen, 

nitrite, 

dissolved 

(mg/L)

Nitrogen, 

NO2 + NO3 

dissolved 

(mg/L)

Nitrogen, 

ammonia 

dissolved 

(mg/L)

Nitrogen, 

ammonia + 

organic total 

(mg/L)

Nitrogen, 

ammonia + 

organic 

dissolved 

(mg/L)

Nitrogen, 

total 

(mg/L)

Phosphorus, 

total 

(mg/L as P)

3-16-99 1700 76 0.001 0.576 0.013 0.10 E.10 0.68 0.029

5-13-99 1417 56 0.001 0.568 0.005 E.10 E.10 0.67 0.034

6-16-99 1130 34 0.001 0.163 0.003 0.27 0.10 0.43 0.902

7-26-99 1730 11 <0.001 0.065 0.002 <0.10 E.10 0.17 0.356

8-18-99 1610 21 <0.001 0.069 0.004 0.25 <0.10 0.32 0.352

9-16-99 1430 33 0.001 0.129 0.028 <0.10 <0.10 0.23 0.085

10-14-99 1115 -- -- -- -- -- -- -- --

5-16-00 1815 53 0.001 0.818 0.002 E.10 E.10 0.92 0.036

6-20-00 1645 36 <0.001 0.252 0.002 <0.10 <0.10 0.35 0.203

7-18-00 1315 25 0.001 0.077 <0.002 <0.10 <0.10 0.18 0.424

8-31-00 1345 28 0.001 0.080 <0.002 <0.10 <0.10 0.18 0.244

9-21-00 1620 48 <0.001 0.220 0.004 <0.10 <0.10 0.32 0.077
26

Appendix 1. Physical properties and water-quality constituents of streamflow samples collected from the Tlikakila River, 

March 1999 through September 2000 (USGS station number 15297970)—Continued

Date Time

Phosphorus 

dissolved 

(mg/L as P)

Phosphorus 

ortho 

dissolved 

(mg/L as P)

Iron dissolved 

(ug/L as Fe)

 Manganese 

dissolved 

(ug/L as Mn)

Dissolved 

organic carbon 

(mg/L as C)

Particulate 

organic 

carbon total 

(mg/L as C)

Suspended 

sediment 

concentration 

(mg/L)

3-16-99 1700 <0.004 0.002 26 15 0.60 <0.2 5

5-13-99 1417 <0.004 0.001 80 8 0.70 <0.2 25

6-16-99 1130 0.004 0.004 80 6 0.70 0.9 710

7-26-99 1730 0.005 0.005 20 6 0.40 0.5 227

8-18-99 1610 <0.004 <0.001 10 5 0.20 0.2 397

9-16-99 1430 <0.004 <0.001 10 3 0.30 0.2 71

10-14-99 1115 -- -- -- -- -- -- 9

5-16-00 1815 E.003 0.003 60 6 0.60 0.2 29

6-20-00 1645 <0.006 <0.001 40 3 0.41 <0.2 676

7-18-00 1315 <0.006 0.003 30 5 E.24 0.2 528

8-31-00 1345 <0.006 0.001 30 5 E.17 0.3 318

9-21-00 1620 <0.006 0.001 <10 3 0.35 <0.2 118
27

Appendix 2. Physical properties and water-quality constituents of streamflow samples collected from the Chokotonk River, 

June 1999 through September 2001 (USGS Station number 15297930)

[ft3/s, cubic feet per second; μs/cm, microsiemens per centimeter; oC), degrees Celsius; mg/L, milligrams per liter]

Date Time Discharge 

(ft3/s)

Specific 

conductance 

(μs/cm)

pH

Water 

temperature 

(

oC)

Dissolved 

oxygen 

(mg/L)

Alkalinity 

(mg/L as 

CaCO3)

Bicarbonate 

(mg/L as 

HCO3)

 Suspended 

sediment 

concentration 

(mg/L)

6-16-99 1416 2,190 28 8.2 6.0 12.5 11 -- 208

7-22-99 1515 1,200 33 7.6 10.0 -- 11 -- 80

8-17-99 1145 1,950 31 7.3 5.5 11.3 12 -- 107

10-14-99 1330 258 74 7.1 0.0 11.6 24 -- 9

6-20-00 1300 944 40 7.2 6.0 12.5 16 -- 25

7-18-00 1120 1,500 30 7.4 4.5 14.3 11 -- 211

7-10-01 1200 -- 35 7.6 4.5 12.8 -- -- --

8-22-01 1130 -- 30 7.0 4.5 12.1 -- -- --

9-17-01 1450 -- 45 7.2 6.5 12.2 -- -- --

Appendix 3. Physical properties and water-quality constituents of streamflow samples collected from the Chulitna River, June 

1999 through September 2001 (USGS station number 15298050)

[ft3/s, cubic feet per second; μs/cm, microsiemens per centimeter; oC, degrees Celsius; mg/L, milligrams per liter]

Date Time Discharge 

(ft3/s)

Specific 

conductance 

(μs/cm)

pH

Water 

temperature 

(

oC)

Dissolved 

oxygen 

(mg/L)

 Alkalinity 

(mg/L as 

CaCO3)

 Suspended 

sediment 

concentration 

(mg/L)

6-17-99 1430 4,090 58 7.1 11.5 10.6 21 9

7-20-99 1710 1,400 77 7.7 12.4 10.8 31 4

8-16-99 1515 4,060 70 7.4 11.2 10.5 28 5

9-13-99 1615 3,160 76 7.5 9.0 11.2 29 5

10-13-99 1245 2,570 76 7.4 1.0 13.2 28 5

6-19-00 1700 1,340 69 7.4 10.0 11.2 28 5

7-19-00 1325 1,570 78 7.8 11.0 10.3 32 5

8-28-00 1900 1,320 85 7.8 11.0 10.0 36 5

9-22-00 1300 3,960 66 7.0 8.0 12.2 24 5

6-4-01 1800 7,420 53 7.1 9.5 12.9 -- --

7-9-01 1830 2,230 71 7.8 14.5 10.1 -- --

8-20-01 1445 2,370 81 7.6 12.0 10.0 -- --

9-25-01 1345 1,870 82 7.0 7.5 11.4 -- --
28

Appendix 4. Physical properties and water-quality constituents of streamflow samples collected from Currant Creek, June 

1999 through September 2001 (USGS station number 15297980)

[ft3/s, cubic feet per second; μs/cm, microsiemens per centimeter; oC, degrees Celsius; mg/L, milligrams per liter]

Date Time Discharge 

(ft3/s)

Specific 

conductance 

(μs/cm)

pH

Water 

temperature 

(

oC)

Dissolved 

oxygen (mg/L)

 Alkalinity 

(mg/L as 

CaCO3)

 Suspended 

sediment 

concentration 

(mg/L)

6-16-99 1655 2,670 45 7.4 7.5 12.1 12 193

7-21-99 1415 1,590 36 7.5 7.0 -- 11 82

8-17-99 1425 1,280 40 7.4 7.5 11.1 13 103

9-15-99 1515 885 51 7.0 6.0 12.6 15 25

10-17-99 1720 279 74 7.3 2.0 11.6 20 7

6-21-00 1100 776 37 7.6 5.4 14.0 12 9

7-18-00 1510 2,760 37 7.5 5.5 13.8 12 162

8-29-00 1215 1,230 36 7.4 6.5 12.0 11 282

9-19-00 1725 297 71 7.4 6.5 14.9 19 3

6-5-01 1200 1,050 54 7.6 6.0 14.3 -- --

7-10-01 1430 1,470 43 7.4 6.0 12.4 -- --

8-22-01 1500 1,620 38 6.9 7.5 11.4 -- --

9-25-01 1645 671 55 7.0 5.5 13.7 -- --

Appendix 5. Physical properties and water-quality constituents of streamflow samples collected from the Kijik River, June 

1999 through September 2001 (USGS station number 15297990)

[ft3/s, cubic feet per second; μs/cm, microsiemens per centimeter; oC, degrees Celsius; mg/L, milligrams per liter]

Date Time Discharge 

(ft3

/s)

Specific 

conductance 

(us/cm)

pH

Water 

temperature 

(

oC)

Dissolved 

oxygen (mg/L)

 Alkalinity 

(mg/L as 

CaCO3)

 Suspended 

sediment 

concentration 

(mg/L)

6-17-99 1600 1,750 76 7.6 7.5 12.7 25 123

7-20-99 1415 857 80 7.6 10.5 11.1 24 8

8-17-99 1730 1,130 78 7.7 12.5 9.4 24 3

9-14-99 0915 758 88 7.1 7.5 12.3 25 2

10-13-99 1445 432 88 7.3 3.5 11.2 28 6

6-21-00 1630 586 84 7.6 12.0 11.6 25 3

7-20-00 0930 1,230 78 7.8 9.0 11.6 26 2

8-29-00 1410 620 80 7.7 9.5 10.6 25 3

9-19-00 1550 600 85 7.6 7.5 13.5 27 3

6-5-01 1300 3,000 70 7.7 6.5 13.7 -- --

8-20-01 1630 817 73 7.6 12.0 10.2 -- --

9-25-01 1530 447 86 7.0 8.5 11.7 -- --
29

Appendix 6. Physical properties and water-quality constituents of streamflow samples collected from the Tanalian River, June 

1999 through September 2001 (USGS station number 15298010)

[ft3/s, cubic feet per second; μs/cm, microsiemens per centimeter; oC, degrees Celsius; mg/L, milligrams per liter]

Date Time Discharge 

(ft3/s)

Specific 

conductance 

(us/cm)

pH

Water 

temperature 

(

oC)

Dissolved 

oxygen 

(mg/L)

 Alkalinity 

(mg/L as 

CaCO3)

 Suspended 

sediment 

concentration 

(mg/L)

6-17-99 1800 5,920 54 7.4 7.0 13.0 13 5

7-19-99 1845 1,620 44 7.5 11.3 11.4 10 3

8-16-99 1640 1,850 44 7.2 11.5 11.3 11 1

9-13-99 1801 650 50 7.1 10.5 10.4 11 1

10-14-99 1650 543 52 7.0 5.5 10.3 12 3

5-15-00 1500 179 54 7.4 8.5 11.5 13 2

6-21-00 1820 750 47 7.7 10.5 11.4 12 1

7-19-00 1530 1,640 46 7.8 11.5 10.1 11 1

8-30-00 1315 656 45 7.3 11.0 10.5 11 2

9-20-00 1100 489 50 7.2 8.5 12.0 12 1

6-5-01 1545 1,560 54 7.5 7.0 13.8 -- --

8-20-01 1730 2,090 45 7.5 13.5 13.4 -- --

9-24-01 1700 450 44 7.0 10.0 11.4 -- --

Appendix 7. Physical properties and water-quality constituents of streamflow samples collected from Lake Clark outlet, June 

1999 through September 2001 (USGS station number 15299000)

[ft3/s, cubic feet per second; μs/cm, microsiemens per centimeter; oC, degrees Celsius; mg/L, milligrams per liter]

Date Time Discharge 

(ft3/s)

Specific 

conductance 

(us/cm)

pH

Water 

temperature 

(

oC)

Dissolved 

oxygen 

(mg/L)

 Alkalinity 

(mg/L as 

CaCO3)

 Suspended 

sediment 

concentration 

(mg/L)

6-17-99 1030 13,500 62 7.9 4.5 12.5 20 1

7-19-99 1705 19,100 56 7.8 6.0 13.6 20 2

8-16-99 1300 21,400 57 7.6 10.5 10.3 20 1

9-14-99 1400 15,300 58 7.3 11.0 11.8 21 1

10-12-99 1620 10,800 62 7.3 6.5 11.2 20 1

6-19-00 1230 8,620 55 7.3 5.0 11.8 20 1

7-19-00 1115 17,100 58 7.6 9.5 11.4 21 1

8-28-00 1645 11,600 58 7.8 11.5 11.0 21 3

9-22-00 1100 8,690 58 7.0 8.5 12.4 20 5

6-4-01 1600 8,530 59 7.9 6.0 14.1 -- --

7-9-01 1630 23,800 60 7.8 7.5 11.6 -- --

8-20-01 1230 21,600 58 7.6 7.6 10.4 -- --

9-25-01 1100 10,600 57 7.2 10.0 10.8 -- --