In cooperation with the

U.S. ENVIRONMENTAL PROTECTION AGENCY

Water-Quality, Bed-Sediment, and Biological 

Data (October 1997 Through September 1998] 

and Statistical Summaries of Data for Streams in 

the Upper Clark Fork Basin, Montana

By Kent A. Dodge, Michelle I. Hornberger, and Robin M. Bouse

Open-File Report 99-251

U.S. Department of the Interior 

U.S. Geological Survey
U.S. Department of the Interior

BRUCE BABBITT, Secretary

U.S. Geological Survey

Charles G. Groat, Director

Any use of trade, product, or firm name in this publication is for 

descriptive purposes only and does not imply endorsement by the 

U.S. Government

Helena, Montana 

September 1999

For additional information write to:

District Chief 

U.S. Geological Survey 

3162 Bozeman Avenue 

Helena, MT 59601-6456

Copies of this report may be purchased from:

U.S. Geological Survey 

Branch of Information Services 

Box 25286 

Denver, CO 80225-0286
CONTENTS

Page

Abstract...............................................................................................................................^ 1

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

Sampling locations and types of data.................................................................................................................................... 3

Water-quality data................................................................................................................................................................. 3

Methods...................................................................................................................................................................... 3

Results........................................................................................................................................................................ 5

Quality assurance....................................................................................................................................................... 5

Bed-sediment data................................................................................................................................................................. 9

Methods............................................................. 9

Results.......................................................................................................................................................................^ 10

Quality assurance....................................................................................................................................................... 10

Biological data....................................................................................................................................................................... 11

Methods........................................................................................................._^ 11

Results........................................................................................................................................................................ 12

Quality assurance.....................................................................................................................................................^ 12

Statistical summaries of data................................................................................................................................................. 12

References cited..................................................................................................................................................................... 13

Data........................................................................................................................................................................................ 15

ILLUSTRATION

Figure 1. Map showing location of study area................................................................................................................. 2

TABLES

Table 1. Type and period of data collection at sampling stations in the upper Clark Fork basin, Montana.................... 4

2. Properties measured onsite and constituents analyzed in samples of water, bed sediment, and biota from

the upper Clark Fork basin, Montana.............................................................................................................. 5

3. Data-quality objectives for analyses of water-quality samples collected in the upper Clark Fork basin,

Montana........................................................................................................................................................... 7

4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998............ 16

5.-7. Daily streamflow and suspended-sediment data, October 1997 through September 1998, for:

5. Clark Fork at Deer Lodge, Montana....................................................................................................... 35

6. Clark Fork at Turah Bridge, near Bonner, Montana............................................................................... 39

7. Clark Fork above Missoula, Montana..................................................................................................... 43

8. Chemical and suspended-sediment analyses of field replicates for water samples, upper Clark Fork

basin, Montana................................................................................................................................................. 47

9. Precision of chemical and suspended-sediment analyses of field replicates for water samples, upper

Clark Fork basin, Montana.............................................................................................................................. 48

10. Precision of chemical analyses of laboratory replicates for water samples, upper Clark Fork basin,

Montana................................................................................................................^^ 49

11. Recovery efficiency for trace-element analyses of laboratory-spiked deionized-water blanks......................... 50

12. Recovery efficiency for trace-element analyses of laboratory-spiked stream samples, upper Clark

Fork basin, Montana........................................................................................................................................ 51

13. Chemical analyses of field blanks for water samples......................................................................................... 52

14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, August 1998.......... 53

15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, August 1998...................... 54

16. Recovery efficiency for trace-element analyses of standard reference materials for bed sediment................... 55

CONTENTS Hi
TABLES (Continued)

Page

Table 17. Trace-element analyses of procedural blanks for bed sediment........................................................................ 56

18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 1998........................................... 57

19. Recovery efficiency for trace-element analyses of standard reference material for biota................................. 59

20. Trace-element analyses of procedural blanks for biota..................................................................................... 60

21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985

through September 1998................................................................................................................................. 61

22. Statistical summary of fine-grained bed-sediment data for the upper Clark Fork basin, Montana,

August 1986 through August 1998................................................................................................................. 76

23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, August 1993

through August 1998....................................................................................................................................... 81

24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through

August 1998.................................................................................................................................................... 86

CONVERSION FACTORS AND ABBREVIATED WATER-QUALITY UNITS

____________________Multiply_________________By_______________To obtain______________

cubic foot per second (ft /s) 0.028317 cubic meter per second

foot (ft) 0.3048 meter (m)

gallon (gal) 3.785 liter (L)

gallon (gal) 3,785 milliliter (mL)

inch (in.) 25.4 millimeter (mm)

inch (in.) 25,400 micrometer (um)

mile (mi) 1.609 kilometer

ounce (oz) 28.35 gram (g)

part per million 1 microgram per gram (ug/g)

square mile (mi2) 2.59 square kilometer 

____________ton per day (ton/d)______________907.2______________kilogram per day________

Temperature can be converted from degrees Celsius (°C) to degrees Fahrenheit (°F) by the equation:

°F = 9/5 (°C) + 32 

Abbreviated water-quality units used in this report:

ug/g micrograms per gram

ug/L micrograms per liter

ug/mL micrograms per milliliter

uS/cm microsiemens per centimeter at 25 degrees Celsius

mg/L milligrams per liter

Water-year definition:

A water year is the 12-month period from October 1 through September 30. It is designated by the calendar year in which it ends.

Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Water-Quality, Bed-Sediment, and Biological Data (October 

1997 through September 1998) and Statistical Summaries of 

Data for Streams in the Upper Clark Fork Basin, Montana

By Kent A. Dodge, Michelle I. Hornberger1 , and Robin M. Bouse 1

ABSTRACT

Water, bed sediment, and biota were sampled in 

streams from Butte to below Missoula as part of a program to characterize aquatic resources in the upper 

Clark Fork basin of western Montana. Sampling stations were located on the Clark Fork and major tributaries. Water-quality data were obtained periodically at 

15 stations during October 1997 through September 

1998 (water year 1998). Data for 15 bed-sediment and 

15 biological stations were obtained in August 1998. 

The primary constituents analyzed were trace elements 

associated with tailings from historical mining and 

smelting activities.

Water-quality data include concentrations of 

selected major ions, trace elements, and suspended sediment in stream samples. Daily values of streamflow, 

suspended-sediment concentration, and suspendedsediment discharge are given for three stations. Bedsediment data include trace-element concentrations in 

the fine-grained and bulk fractions. Biological data 

include trace-element concentrations in whole-body 

tissue of aquatic benthic insects. Quality-assurance 

data are reported for analytical results of water, bed 

sediment, and biota. Statistical summaries of waterquality, bed-sediment, and biological data are provided 

for the period of record at each station since 1985.

INTRODUCTION

The Clark Fork originates near Warm Springs in 

western Montana at the confluence of Silver Bow and 

Warm Springs Creeks (fig. 1). Along the 148-mi reach 

of stream from Silver Bow Creek in Butte to the Clark 

Fork at Milltown Reservoir, six major tributaries enter: 

Blacktail Creek, Warm Springs Creek, Little Blackfoot 

River, Flint Creek, Rock Creek, and Blackfoot River.

Principal surface-water uses in the 6,000-mi2 Clark 

Fork basin above Missoula include irrigation, stock 

watering, light industry, hydroelectric power generation, and habitat for trout fisheries. Current land uses 

primarily are cattle production, logging, mining, and 

recreation. Large-scale mining and smelting had been 

prevalent land uses in the upper basin for more than one 

hundred years, but are now largely discontinued.

Deposits of copper, gold, silver, and le?d ores 

were extensively mined, milled, and smelted in the 

drainages of Silver Bow and Warm Springs Creeks 

from about 1870 to 1980. Moderate- and small-scale 

mining also occurred in the basins of most of the major 

tributaries to the upper Clark Fork. Tailings derived 

from mineral processing commonly contain large 

quantities of trace elements such as arsenic, cadmium, 

copper, lead, and zinc. Tailings have been eroded, 

mixed with stream sediment, and transported downstream since the late 1800's and redeposited in stream 

channels, on flood plains, and in the Warm Springs 

Ponds and Milltown Reservoir. The widely dispersed 

tailings continue to be eroded, transported, ard redeposited along the stream channel and flood plain, especially during high flows. The occurrence of t~ace 

elements in elevated concentrations can pose a risk to 

aquatic biota and human health because they may 

accumulate to potentially toxic levels.

Concern about the potential toxicity of tailings to 

aquatic biota and human health has resulted in a comprehensive effort by State, Federal, and private entities 

to characterize the aquatic resources in the upper Clark 

Fork basin to guide and monitor remedial cleanup 

activities. A long-term data base was considered necessary to detect trends over time in order to evaluate the 

effectiveness of remediation. Water-quality data have 

been collected by the U.S. Geological Survey (USGS)

U.S. Geological Survey, Menlo Park, Calif.

Abstract 1
12353 12340500

MONTANA

Helena

Study area

Base from U.S. Geological 

Survey, State base map, 

1:1.000.000. 1966

461903112440701

461559112443301

461415112450801

EXPLANATION

12324200 STATION AND NUMBER

461903112440701 MISCELLANEOUS SITE AND NUMBER 

STREAMFLOW GAGING 

A Continuous record 

A Periodic measurement 

WATER QUALITY, BED SEDIMENT, BIOTA 

^7 Periodic water quality 

V- Daily suspended sediment 

V~ Once-annual bed sediment 

~V Once-annual biota

10 20 MILES

20 KILOMETERS

Figure 1. Location of study area.

at selected sites in the upper Clark Fork basin since 

1985 (Lambing, 1987, 1988, 1989, 1990, and 1991; 

Lambing and others, 1994, 1995; and Dodge and 

others, 1996, 1997). Trace-element data for bed 

sediment and biota (aquatic benthic insects) have been 

collected intermittently since 1986 at selected sites as 

part of studies on bed-sediment contamination and 

bioaccumulation of metals conducted by the USGS 

National Research Program (Axtmann and Luoma, 

1991; Axtmann and others, 1997; Cain and others,

1992. 1995; Hornberger and others, 1997). In March

1993. an expanded sampling program for water, bed 

sediment, and biota was implemented in cooperation

with the U.S. Environmental Protection Agency to 

provide systematic, long-term monitoring. In 1996, 

water-quality and daily sediment sampling in the 

expanded program was scaled back to a less extensive 

network and reduced sampling frequency. In 1997, the 

water-quality network was partially restored to the 

pre-1996 status (water-quality sampling at fr a, Clark 

Fork below Missoula was not reactivated) and 

sampling frequency was increased to better quantify 

the annual variability in selected constituent".

The purpose of this report is to present waterquality data for 15 stations and trace-element data for

Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
15 bed-sediment and 15 biological stations in the upper 

Clark Fork basin collected from October 1997 through 

September 1998 (water year 1998). Quality-assurance 

data are presented for water quality, bed sediment, and 

biota. Statistical summaries also are provided for 

water-quality, bed-sediment, and biological data collected since 1985.

SAMPLING LOCATIONS AND 

TYPES OF DATA

Sampling stations in the upper Clark Fork basin 

are located on both the Clark Fork mainstem and major 

tributaries from Butte to below Missoula (fig. 1). 

Mainstem sampling sites were selected to divide the 

upper Clark Fork into reaches of relatively uniform 

length, with each reach encompassing either a major 

tributary or depositional environment (Warm Springs 

Ponds and Milltown Reservoir). Tributaries were sampled to describe water-quality characteristics for major 

hydrologic sources in the upper basin and to provide 

reference comparisons to the mainstem for bed sediment and biota. Water-quality data were obtained periodically at 15 stations; daily suspended-sediment data 

were obtained at 3 of these stations. Data for 15 bedsediment and 15 biological stations were obtained 

once-annually (table 1).

A list of properties and constituents analyzed in 

samples of water, bed sediment, and biota is given in 

table 2. Results of analyses for water, bed sediment, 

biota, and associated quality assurance for water year 

1998 are listed in tables 4 through 20 at the back of the 

report. Statistical summaries of water-quality, bed-sediment, and biological data collected between March 

1985 and September 1998 are given in tables 21-24 at 

the back of the report.

Quality assurance of data was maintained 

through the use of documented procedures designed to 

provide environmentally representative data. Acceptable performance of the procedures was verified with 

quality-control samples that were collected systematically to provide a measure of the accuracy, precision, 

and bias of the environmental data and to identify problems associated with sampling, processing, or analysis.

WATER-QUALITY DATA

Water-quality data consist of measurements of 

physical properties and concentrations of chenical and 

physical constituents analyzed in stream samples. 

Samples were collected 5 to 8 times per year on a 

schedule designed to describe seasonal and h)'drologic 

variability. In addition, 11 supplemental samples were 

collected by a contract observer at Clark Fork at Turah 

Bridge, near Bonner and Clark Fork above Missoula to 

better define chemical changes and transport during 

extended high flows, and during the lowering of Milltown Reservoir water levels for dam maintenance.

Methods

Cross-sectional water samples were collected 

from multiple verticals across the stream using depthand width-integration methods described by USGS 

(1977), Knapton (1985), and Edwards and Glysson 

(1988). These methods provide a vertically ?nd laterally discharge-weighted sample that is representative 

of the entire flow through the cross section of £ stream. 

Sampling equipment consisted of standard USGS 

depth-integrating suspended-sediment samplers (DH48, DH-81, and D-74TM), which are either contracted 

of plastic or coated with a non-metallic epoxy paint, 

and equipped with nylon nozzles.

Onsite measurements of water temperature, specific conductance, and pH were made during collection 

of periodic water-quality samples. Onsite sample processing, including filtration and preservation, was performed according to procedures described by Forowitz 

and others (1994), Ward and Harr (1990), USGS 

(1977), and Knapton (1985). Instantaneous streamflow 

at the time of water sampling was determined at all stations, either by direct measurement or from stage-discharge rating tables (Rantz and others, 1982).

Water samples were analyzed for the constituents 

listed in table 2 by the USGS National Water Quality 

Laboratory (NWQL) in Arvada, Colo. The trace elements arsenic, cadmium, copper, iron, lead, manganese, and zinc were analyzed for both dissolved and 

total-recoverable concentrations. Analytical methods 

are described by Fishman and Friedman (1989) and 

Fishman(1993).

Cross-sectional water samples also were collected for analysis of suspended sediment whenever

SAMPLING LOCATIONS AND TYPES OF DATA
»_

» s. CA O. F 3'

I*

2. *

& 9

g a

te <y 5'

5" 

B.

3

JQ

i

Table 1. Type and period of data collection at sampling stations in the upper Clark Fork basin, Montana

[Abbreviations: P, present. Symbol: --, no data]

Station number 

(fig. 1)

12323230

12323250

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324590

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

Station name

Blacktail Creek at Harrison Avenue, at 

Butte

Silver Bow Creek below Blacktail Creek, at 

Butte

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Warm Springs Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek diversion, 

near Racetrack

Clark Fork at Deer Lodge

Little Blackfoot River near Garrison

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula3

Continuous-record 

stream flow

10/83-P

07/88-P

03/72-09/79, 

04/93-P

10/83-P

07/88-P

-

-

~

10/78-P

10/72-P

10/77-P

08/90-P

04/93-P

10/72-P

03/85-P

10/39-P

03/29-P

10/29-P

Periodic water 

quality1

03/93-08/95, 

12/96-P

03/93-08/95, 

12/96-P

03/93-08/95, 

12/96-P

03/93-P

03/93-P

07/88-P

-

--

03/85-P

03/85-P

03/93-P

03/85-P

03/93-P

03/85-P

03/85-P

03/85-P

07/86-P

03/85-09/95

Daily 

suspended 

sediment

~

03/93-09/95

04/93-09/95

-

~

-

--

03/85-08/86, 

04/87-P

- 

--

~

03/85-P

07/86-04/87, 

06/88-09/95

07/86-04/87, 

06/88-01/96, 

03/96-P

"~

Fine-grained 

bed sediment2

07/92-P

07/92-P

08/95, 08/97

08/87, 

08/9 1-P

08/96-P

08/96-P

08/96-P

08/86, 08/97, 

08/90-P

08/86,08/87,08/94, 

08/98

07/92-P

08/86, 08/89, 

07/92-P

08/86, 08/87, 

08/9 1-P

08/86,08/87,08/89, 

08/91-P

08/86, 

08/91-P

08/86, 08/87, 

08/91, 

08/93-96, 08/98

08/97-P

08/86, 

08/90-P

Bu

sed

0

0

0

0

'Onsite measurements of physical properties and laboratory analyses of major ions, trace elements, and suspended sediment Prior to March 1993, laboratory analyses inc

pended sediment, with the exception of Clark Fork below Missoula. 

2Laboratory analyses of trace elements. 

3 Bed sediment and biota sampled about 30 miles downstream from water-quality station to conform to previous sampling location.
Table 2. Properties measured onsite and constituents analyzed in samples of water, 

bed sediment, and biota from the upper Clark Fork basin, Montana

Water

Property

Streamflow

Specific conductance

pH

Temperature

Constituent

Hardness

Calcium

Magnesium

Arsenic

Cadmium

Copper

Iron

Lead

Manganese

Zinc

Suspended sediment

Bed sediment

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Biota

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

periodic water-quality samples were collected. These 

samples were analyzed for suspended-sediment concentration and the percentage of suspended sediment 

finer than 0.062-mm diameter (silt size and smaller) 

by the USGS sediment laboratory in Helena, Mont., 

according to methods described by Guy (1969) and 

Lambing and Dodge (1993).

At the three daily suspended-sediment stations 

(table 1), suspended-sediment samples were collected 

2 to 9 times per week. These samples were collected 

by local contracted observers using the depth-integration method at a single vertical near mid-stream. The 

samples were analyzed for suspended-sediment concentration and were used to determine daily mean suspended-sediment concentrations according to methods 

described by Porterfield (1972).

Results

Water-quality data for samples collected periodically during October 1997 through September 1998 

(water year 1998) are presented in table 4. The types of 

data include instantaneous streamflow, onsite measurements of water-quality properties, and analytical results 

for chemical constituents and suspended sediment.

Daily streamflow and suspended-sediment data 

for water year 1998 at the three daily suspended-sediment stations are given in tables 5 through 7. Monthly 

descriptive statistics for each parameter are provided

along with totals for the annual discharge of water and 

suspended sediment.

Quality Assurance

Quality-assurance procedures used for the collection and field processing of water-quality samples 

are described by Horowitz and others (1994), Ward and 

Harr (1990), Edwards and Glysson (1988), Knapton 

and Nimick (1991), and Knapton (1985). Standard 

procedures used by the NWQL for internal sample handling and quality assurance are described by Friedman 

and Erdmann (1982), Jones (1987), and Pritt and Raese 

(1992). Quality-assurance procedures used by the 

Montana District sediment laboratory are described by 

Lambing and Dodge (1993).

The quality of analytical results reported for 

water-quality samples was evaluated by quality-control 

samples that were submitted from the field and analyzed concurrently in the laboratory with rout'ie samples. These quality-control samples consisted of 

replicates, spikes, and blanks which provide quantitative information on the precision and bias of the overall 

field and laboratory process. Each type of quality-control sample was submitted at a proportion equivalent to 

about 5 percent of the total number of water-quality 

samples. Therefore, the total number of quality-control samples represented about 15 percent of the total 

number of water-quality samples.

WATER-QUALITY DATA
In addition to quality-control samples submitted 

from the field, internal quality-assurance practices at 

the NWQL are performed systematically to provide 

quality control of analytical procedures (Pritt and 

Raese, 1992). These internal practices include analyses of quality-control samples such as calibration standards, standard reference water samples, replicate 

samples, deionized-water blanks, or spiked samples at 

a proportion equivalent to at least 10 percent of the 

sample load. The NWQL participates in a blindsample program where standard reference water samples prepared by the USGS Branch of Quality Systems 

are routinely inserted into the sample line for each analytical method at a frequency proportional to the sample load. The laboratory also participates in external 

evaluation studies twice-yearly with the U.S. Environmental Protection Agency, the Canadian Center for 

Inland Water, and the Branch of Quality Systems to 

assess analytical performance.

Replicate data can be obtained in different ways 

to provide an assessment of precision (reproducibility) 

of analytical results. Replicate samples are two or 

more samples considered to be essentially identical in 

composition. Replicate samples can be obtained in the 

field by either repeating the collection process to obtain 

two or more samples or by splitting a single sample into 

two or more subsamples which are then analyzed separately (field replicate). Likewise, a single sample can 

be analyzed two or more times in the laboratory to 

obtain a measure of analytical variability (laboratory 

replicate).

Precision of analytical results for field replicates 

is affected by numerous sources of variability within 

the field and laboratory environments, including sample collection, sample processing, and sample analysis. 

To provide data on precision for samples exposed to all 

sources of variability, chemical-replicate samples were 

obtained in the field by splitting a composite stream 

sample. Suspended-sediment replicate samples were 

obtained in the field by concurrently collecting two 

independent cross-sectional samples. Analyses of 

these field replicates indicate the reproducibility of 

environmental data that are affected by the combined 

variability potentially introduced by field and laboratory processes.

Analytical precision was evaluated with laboratory replicates, which excluded field sources of variability. Two independent analyses were made of an

individual sample selected randomly in the laboratory 

from the group of samples comprising each analytical 

run. A separate analysis of the sample was made at the 

beginning and end of each analytical run to provide 

information on the reproducibility of laboratory analytical results independent of possible variability caused 

by field collection and processing of samples.

Spiked samples are used to evaluate the ability of 

an analytical method to accurately measure a known 

amount of analyte added to a sample. Because some 

constituents in stream water can potentially interfere 

with the analysis of a targeted analyte, it is important to 

determine whether such effects are causing inaccurate 

analyses. Deionized-water blanks and aliquots of 

stream samples were spiked in the laboratory with 

known amounts of the same trace elements rnalyzed in 

water samples. Analyses of spiked blanks indicate if 

the spiking procedure and analytical method are within 

control for a water matrix that is presumably free of 

chemical interference. Analyses of spiked aliquots of 

stream samples indicate if the chemical matrix of the 

stream water interferes with the analytical measurement and whether these interferences could contribute 

significant bias to reported trace-element concentrations for stream samples.

Blank samples of deionized water were routinely 

analyzed to identify the presence and magnitude of 

contamination that potentially could bias analytical 

results. The particular type of blank sample routinely 

tested was a "field" blank. Field blanks are aliquots of 

deionized water that are certified as trace-element free 

and are processed through the sampling equipment 

used to collect stream samples. These blanks are then 

subjected to the same processing (sample splitting, filtration, preservation, transportation, and laboratory 

handling) as stream samples. Blank sample? are analyzed for the same constituents as those of stream samples to identify whether any detectable concentrations 

exist.

All water samples were handled in accordance 

with chain-of-custody procedures that provide documentation of sample identity, shipment, receipt, and 

laboratory handling. All samples submitted from a 

sampling episode were stored and analyzed as a discrete sample group, independent of other samples submitted to the NWQL. Therefore, statistical descriptions of quality-control data generated for this program

6 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
are directly applicable to the analytical results for 

stream samples reported herein.

Data-quality objectives (table 3) were established for water-quality data as part of the study plan 

for the expanded long-term monitoring program that 

was initiated in 1993. The objectives identify analytical requirements of detectability and serve as a guide 

for identifying questionable data by establishing 

acceptable limits for precision and bias of laboratory 

results. Comparisons of quality-control data to dataquality objectives are used to evaluate whether sampling and analytical procedures are producing environmentally representative data in a consistent manner. 

Data that did not meet the objectives were evaluated for 

acceptability, and corrective action was taken, when 

appropriate.

The precision of analytical results for a constituent can be determined by estimating a standard deviation of the differences between replicate 

measurements for several sets of samples. Trese replicate measurements may consist either of individual 

analyses of a pair of samples considered to b^ essentially identical (field replicates) or multiple analyses of 

an individual sample (laboratory replicates). The differences in concentration between replicate analyses 

can be used to estimate a standard deviation according 

to the following equation (Taylor, 1987):

where

S 

d 

k

2k (D

standard deviation of the difference in 

concentration between replicate analyses, 

difference in concentration between each 

pair of replicate analyses, and 

number of pairs of replicate analyses.

Table 3. Data-quality objectives for analyses of water-quality samples collected in the upper Clark Fork basin, Montana 

[Abbreviations: ng/L, micrograms per liter; mg/L, milligrams per liter; mm, millimeter. Symbol: , not determined]

Data-quality objectives

Detectability

Constituent

Precision

Maximum relative 

Minimum standard deviation of

reporting 

level

Calcium, dissolved

Magnesium, dissolved

Arsenic, total recoverable

Arsenic, dissolved

Cadmium, total recoverable

Cadmium, dissolved

Copper, total recoverable

Copper, dissolved

Iron, total recoverable

Iron, dissolved

Lead, total recoverable

Lead, dissolved

Manganese, total recoverable

Manganese, dissolved

Zinc, total recoverable

Zinc, dissolved

Sediment, suspended

Sediment, suspended (percent finer than 0.062 mm)

0.02

.01

1

1

1

.1

1

1

10

5

1

.6

10

2

10

10

1

1

mg/L

mg/L

Mg/L

Mg/L

Mg/L

Mg/L

Mg/L

Mg/L

Mg/L

Mg/L

Mg/L

Mg/L

Mg/L

Mg/L

Mg/L

Mg/L

mg/L

percent

laboratory replicate 

analyses, 

in percent

20

20

20

20

20

20

20

20

20

20

20

20

20

20

20

20

--

-

Bhs

Maxrnum 

deviation of

spike recovery, 

in percent

-

--

25

25

25

25

25

25

25

25

25

25

25

25

25

25

--

--

WATER-QUALITY DATA
Precision also can be expressed as a relative standard deviation (RSD), in percent, which is computed 

from the standard deviation and the mean concentration for all the replicate analyses. Expressing precision 

relative to a mean concentration standardizes comparison of precision among individual constituents. The 

RSD, in percent, is calculated according to the following equation (Taylor, 1987):

RSD = - x 100 (2)

where

RSD = relative standard deviation,

S = standard deviation, and

x = mean of all replicate concentrations.

Paired analyses of field replicates are presented 

in table 8. The precision estimated for each constituent 

based on these paired results, which include both field 

and laboratory sources of variability, is reported in 

table 9. Statistics for precision of field-replicate analyses were based on the values reported in table 8, which 

are rounded to standard USGS reporting levels for the 

particular constituent and its analytical method 

(Timme, 1994).

Data-quality objectives for precision are not 

directly applicable to field replicates because of the 

inability to determine whether the variability results 

from field sample collection and processing, or laboratory handling and analysis. However, a statistical calculation of precision for the field replicates is provided 

in table 9 to illustrate overall reproducibility of environmental data that incorporates both field and laboratory sources of variability. Relative standard deviations estimated from differences in analytical results 

between field replicates were within 20 percent for all 

constituents.

Analytical precision for chemical constituents 

based on replicate laboratory analyses of individual 

samples, which includes only laboratory sources of 

variability, is reported in table 10. Statistics for analytical precision of laboratory-replicate analyses are

based on unrounded values stored in laboratory data 

files.

The data-quality objective for analytical precision of laboratory-replicate analyses is a maximum relative standard deviation of 20 percent. Precision 

estimates for laboratory-replicate analyses (table 10) 

were within the 20-percent relative standard deviation 

limit for all constituents, except dissolved lead. The 

relative standard deviation for dissolved leM (23 percent) barely exceeded the acceptable limit, and was 

affected primarily by measurements at or below instrument detection limits. The precision data, therefore, 

indicate acceptable reproducibility for labo^tory-replicate analyses for all constituents, with the possible 

exception of dissolved lead concentrations near the 

detection limit.

Analyses of an unspiked sample and r spiked aliquot of the same sample provide a measure of the 

recovery efficiency for the analytical method within 

the chemical matrix of the sample. Spike recovery, in 

percent, was calculated using equation 3 (see below).

The data-quality objective for acceptable spike 

recovery of trace elements in water samples was a maximum deviation of 25 percent from a theoretical 100- 

percent recovery of added constituent. At the laboratory, a spiked deionized-water blank and a spiked aliquot of a stream sample were prepared and analyzed 

along with the original unspiked sample. Tli^ differences between the spiked and unspiked sample concentrations were determined and used to compute recovery 

according to equation 3. If the spike recovery for a 

trace element was outside a range of 75 to 125 percent, 

the instrument was recalibrated and the entire sample 

set and spiked samples were reanalyzed for that particular trace element until recoveries were improved to 

the extent possible. Results of recovery efficiency for 

individual trace elements in spiked deionized-water 

blanks and spiked stream samples are presented in 

tables 11 and 12, respectively.

The mean spike recovery for deionized-water 

samples spiked with trace elements ranged from 91.5 to 

105.4 percent. The mean spike recovery fo" spiked

Spike recovery, in percent = spiked sample concentration - unspiked sample concentration x 100

spike concentration

(3)

8 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
stream samples ranged from 90.1 to 105.0 percent. The 

95-percent confidence intervals (Taylor, 1987) for the 

mean of spike recovery for each constituent analyzed in 

stream samples (table 12) did not exceed a 25-percent 

deviation from an expected 100-percent recovery.

High or low bias is indicated if the confidence 

interval does not include 100 percent recovery. All 

laboratory-spiked stream samples (table 12) had confidence intervals for percent recovery that included 100 

percent, except for dissolved arsenic. Dissolved 

arsenic recoveries were slightly low, with the 95-percent confidence interval for spiked stream samples 

ranging from 85.5 to 94.7 percent. Because the mean 

spike recoveries met data-quality objectives, no adjustments were made to analytical results for stream samples on the basis of spike recoveries.

Analytical results for field blanks are presented 

in table 13. A field blank with constituent concentrations equal to or less than the minimum reporting level 

for the analytical method indicates that the entire process of sample collection, field processing, and laboratory analysis is presumably free of significant 

contamination. If detectable concentrations in field 

blanks were equal to or greater than twice the minimum 

reporting level (typical measurement precision at the 

detection level), the concentrations were noted during 

data review. Analytical results from the field blank for 

the next sample set is evaluated for a consistent trend 

that may indicate systematic contamination. Sporadic, 

infrequent exceedances of twice the minimum reporting level probably represent random contamination or 

instrument calibration error that is not persistent in the 

process and which is not likely to cause significant positive bias in a long-term record of analytical results. 

However, if concentrations for a particular constituent 

exceed twice the minimum reporting level in field 

blanks from two consecutive field trips, blank samples 

are collected from individual components of the processing sequence and are submitted for analysis in 

order to identify the source of contamination.

Constituent concentrations in field blanks were 

almost always less than the minimum reporting level. 

There was only one occurrence of a value equaling 

twice the minimum reporting level (calcium), and there 

were no occurrences of detectable concentrations for 

any trace element in two consecutive blank samples. 

Therefore, the analytical results for field blanks indicate no systematic contamination that would bias the 

reported water-quality data for stream samples.

BED-SEDIMENT DATA

Bed-sediment data consist of analyses of traceelement concentrations in the fine-grained and bulk 

(fine plus coarse) fractions of the bed sediment sample. 

Bed-sediment samples are collected once-annually 

during low, stable flow conditions to facilitate data 

comparisons among years.

Methods

Bed-sediment samples were collected in August 

1998 using protocols described by E.V. Axtmann (U.S. 

Geological Survey, written commun., 1994). Samples 

were collected from the surfaces of streambed deposits 

in low-velocity areas near the edge of the stream using 

an acid-washed polypropylene scoop. Whenever possible, samples were collected from both sides of the 

stream. Three composite samples of fine-grained bed 

sediment and one composite sample of bulk bed sediment were collected at each site.

Individual samples of fine-grained bed sediment 

were collected by scooping material from the surfaces 

of three to five randomly selected deposits along pool 

or low-velocity areas. The three to five individual samples were combined to form a single composite sample. 

This collection process was repeated three time^ to 

obtain three composite samples. Each composite sample was wet-sieved onsite through a 0.064-mm nylonmesh sieve using ambient stream water. The fraction 

of bed sediment in each composite sample that was 

finer than 0.064 mm was transferred to an acid-washed 

500-mL polyethylene bottle and transported to the laboratory on ice.

Individual samples of bulk bed sediment also 

were collected by scooping material from the surfaces 

of three to five randomly selected deposits. Because 

the streambed at most sampling locations is predominantly gravel and cobble, deposits were selectee? where 

cobbles and gravel could be excluded from the samples. Bulk bed-sediment samples are not sieved and 

generally are composed of particles smaller than about 

10 mm in diameter. The individual unsieved samples 

were composited into an acid-washed polyethy'ene 

bottle and transported to the laboratory on ice.

BED-SEDIMENT D\TA
Bed-sediment samples were prepared for analysis at the USGS National Research Program laboratory 

in Menlo Park, Calif. Fine-grained and bulk bed-sediment samples were oven-dried at 60°C and ground 

using an acid-washed ceramic mortar and pestle. 

Duplicate aliquots of approximately 0.6 g of sediment 

from each of the three composite fine-grained bed sediment samples were digested using a hot, concentrated 

nitric acid reflux according to methods described by 

Luoma and Bryan (1981). Two aliquots were similarly 

digested from the single composite sample of bulk bed 

sediment. After a digestion period of up to several 

weeks, the aliquots were evaporated to dryness on a hot 

plate. The dry residue was redissolved with 20 mL of 

0.6 N (normal) hydrochloric acid. The reconstituted 

aliquots then were filtered through a 0.45-j^m filter 

using a syringe and in-line disposable filter cartridge. 

The filtrate was subsequently diluted to either a 1:5 or 

1:10 ratio with 0.6 N hydrochloric acid. These final 

solutions were submitted to the Geology Department at 

the University of Montana, Missoula, Mont., to be analyzed for cadmium, chromium, copper, iron, lead, manganese, nickel, silver, and zinc using Inductively 

Coupled Argon Plasma Emission Spectroscopy 

(ICAPES).

Results

Concentrations of trace elements measured in 

samples of fine-grained and bulk bed sediment collected during August 1998 are summarized in tables 14 

and 15, respectively. Liquid-phase concentrations, in 

j.ig/mL, that were analyzed in the reconstituted aliquots 

of digested bed sediment were converted to solid-phase 

concentrations, in |^g/g, using the following equation:

|qg/mL x volume of digested sample, in mL 

dry weight of sample, in g x dilution ratio

The reported solid-phase concentrations in table 14 

and 15 are the means of all analyses of replicate 

aliquots from each composite sample collected at the 

site. Because the conversion from liquid-phase to 

solid-phase concentration is dependent on both the 

dilution ratio and the dry weight of the sample, 

minimum reporting levels for some trace elements 

may differ among stations and among years.

Quality Assurance

The protocols for field collection ar d processing 

of bed-sediment samples are designed to prevent contamination from metal sources. Non-metallic sampling 

and processing equipment was acid-washed and rinsed 

with deionized water prior to the first sample collection. Nylon-mesh sieves were washed in a laboratorygrade detergent and rinsed with deionized water. All 

equipment was given a final rinse onsite with stream 

water. Sampling equipment that was reused at each site 

was rinsed between sites with 10-percent nitric acid, 

deionized water, and stream water. Separate sieves 

were used at each site and, therefore, did not require 

between-site cleaning.

Quality assurance of analytical results for bed 

sediment included laboratory instrument calibration 

with standard solutions and analysis of quality-control 

samples designed to identify the presence and magnitude of bias (E.V. Axtmann, written commun., 1994). 

Quality-control samples consisted of standard reference materials and procedural blanks. Each type of 

sample was analyzed in a proportion equivalent to 

about 10 to 20 percent of the total numbe" of bedsediment samples.

Standard reference materials (SRM) are commercially prepared materials that have certified concentrations of trace elements. Replicate rialyses of 

standard reference materials are used to indicate the 

reproducibility of analytical results and tH ability of 

the method to accurately measure a known quantity of 

a constituent. Recovery efficiency of trace-element 

analyses of standard reference materials for bed sediment is summarized in table 16. Two standard reference materials consisting of agricultural soils 

representing low and high concentrations of trace elements were analyzed to test recovery efficiency for a 

range of concentrations generally similar to those 

occurring in the upper Clark Fork basin. The digestion 

process used to analyze bed-sediment samples is not a 

"total" digestion (does not liberate elemer+s associated 

with crystalline lattices); therefore, 100-percent recovery may not be achieved for elements strongly bound to 

the sediment. The percent recovery of trace elements 

in standard reference materials when usir<j less than a 

total digestion is useful to indicate which trace elements display strong sediment-binding characteristics 

and whether analytical recovery is consistent between 

multiple sets of analyses.

10 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Although data-quality objectives have not been 

established for bed sediment, percent recoveries are 

shown in table 16 to illustrate analytical performance. 

Elements with mean recoveries outside a 25-percent 

deviation from complete (100 percent) recovery were 

cadmium, chromium, lead, and silver for the low-concentration range (SRM 2709), and chromium for the 

high-concentration range (SRM 2711). Chromium had 

the lowest recovery (63.1 and 68.4 percent) of all the 

elements. Lead and silver concentrations were not 

detected in the low-range SRM (2709). The reason for 

the lack of measurable recoveries is believed to be the 

result of analyzing concentrations very close to the 

detection limit, coupled with signal enhancement 

resulting from matrix interference. Because very few 

bed-sediment samples have lead and silver concentrations as low as SRM 2709, no adjustments were made 

to trace-element concentrations in bed-sediment samples on the basis of recovery efficiencies.

Procedural blanks for bed-sediment samples 

consisted of the same reagents used for sample digestion and reconstitution. Concentrated nitric acid used 

for sample digestion was heated and evaporated to dryness. After evaporation, 0.6 N hydrochloric acid was 

added quantitatively to the dry residue to obtain the 

same dilution ratio as that used in the analysis of bed 

sediment. Procedural blanks, therefore, represent the 

same chemical matrix as the reagents used to digest and 

reconstitute bed-sediment samples. Analytical results 

for procedural blanks can indicate the presence and 

magnitude of potential contamination associated with 

sample handling and analysis in the laboratory environment. Results of trace-element analyses of procedural 

blanks for bed sediment are in table 17.

Analytical results of procedural blanks are 

reported as a liquid-phase concentration, in fig/mL, 

which is equivalent to parts per million. Determination 

of the significance of a detectable blank concentration 

is based on the magnitude of the equivalent solid-phase 

concentration, in Lig/g, relative to the ambient concentration of the trace element in bed-sediment samples. 

Because sample weights of individual aliquots may 

vary, the relative significance of blank concentrations 

may differ among samples. If a detectable blank concentration, after conversion to a solid-phase concentration, represents 10 percent or more of the ambient 

solid-phase concentration, then the blank concentration 

is subtracted to remove potential contamination bias. 

Almost all procedural blanks had concentrations less

than analytical detection levels. Only iron and zinc 

were detected in concentrations more than twic^ the 

detection level. None of the detectable concentrations 

in blanks were greater than 10 percent of the ambient 

concentration. Therefore, no adjustments were made 

to trace-element concentrations in bed-sediment samples on the basis of procedural blanks.

BIOLOGICAL DATA

Biological data consist of analyses of trace-element concentrations in the whole-body tissue of 

aquatic benthic insects. Insect samples are collected 

once-annually at the same sites and dates as bed-sediment samples (table 1), allowing for a direct comparison of annual results.

Methods

Insect samples were collected using protocols 

described in Hornberger and others (1997). Immature 

stages of aquatic benthic insects were collected using a 

large nylon-mesh kick net. A single riffle at each station was sampled repeatedly until an adequate number 

of individuals was collected to provide sufficient mass 

for analysis. Targeted taxa for collection were Hydropsyche spp., and Arctopsyche grandis, Order Trichoptera (caddisflies), and Claassenia sabulosa, Order 

Plecoptera (stoneflies). Samples of each taxon were 

stored separately, by genus, in acid-washed plastic containers. Containers were kept on ice in the field while 

the insects were allowed to evacuate the gut consents in 

ambient stream water for a period of six to eight hours. 

Excess water then was drained and insects were frozen 

for transport to the laboratory.

Insect samples were processed and analyzed at 

the USGS National Research Program laborato"y in 

Menlo Park, Calif. Insects were thawed and rinsed 

with ultra-pure deionized water to remove parti culate 

matter, then sorted to their lowest possible taxonomic 

level. When large numbers of specimens were collected from a station, similar-sized individuals were 

composited into replicate subsamples. Subsamples 

were placed in tared scintillation vials and oven-dried 

at 70°C. Subsamples were weighed to obtain a final 

dry weight and digested by reflux using concertrated 

nitric acid (Cain and others, 1992). After digestion, 

insect samples were evaporated to dryness on a hot 

plate. The dry residue was reconstituted in 0.6 N 

hydrochloric acid, filtered through a 0.45-um filler, and

BIOLOGICAL DATA
analyzed undiluted by ICAPES for cadmium, chromium, copper, iron, lead, manganese, nickel, and zinc.

Results

Concentrations of trace elements in whole-body 

tissue of aquatic insects collected during August 1998 

are summarized in table 18. The variability in the number of composite samples among species and among 

sites reflects differences in insect abundance, with the 

number of composite samples increasing with the relative abundance of insects. Liquid-phase concentrations 

analyzed in the reconstituted samples were converted 

to solid-phase concentrations using equation 4. As in 

bed sediment, minimum reporting levels may differ 

among sites as a result of variable sample weights. In 

general, the smaller the biological sample weight (a 

function of insect abundance), the higher the minimum 

reporting level. Therefore, higher minimum reporting 

levels do not necessarily imply a higher trace-element 

concentration in tissue.

Two species of Hydropsyche were collected for 

this study: Hydropsyche occidentalis and Hydropsyche cockerelli. Species that could not be positively 

identified were considered to belong to the morosa 

group and are categorized as Hydropsyche spp. or 

Hydropsyche morosa group.

Quality Assurance

The protocols for field collection and processing 

of biota samples are designed to prevent contamination 

from metal sources. Non-metallic nets, sampling, and 

processing equipment were employed in all sample 

collection. Equipment was acid-washed and rinsed in 

ultra-pure deionized water prior to the first sample collection. Nets and equipment were thoroughly rinsed in 

ambient stream water at each new mainstem station. 

New nets and depuration chambers were used for the 

tributary stations. Biota samples were collected along 

an increasing concentration gradient to minimize 

effects from potential station-to-station carryover contamination.

Quality assurance of analytical results for biota 

samples included laboratory instrument calibration 

with standard solutions and analyses of quality-control 

samples designed to identify the presence and magnitude of bias. Quality-control samples consisted of standard reference material and procedural blanks. Each 

type of sample was analyzed in a proportion equivalent 

to about 10 to 20 percent of the total number of biota 

samples.

Recovery efficiency for trace-elemert analyses 

of standard reference material for biota is summarized 

in table 19. The reference material tested vas lobster 

hepatopancreas. Data-quality objectives have not been 

established for analytical recovery in biota, but percent 

recoveries are shown to illustrate analytical performance. Mean recoveries were within 20 percent of 

complete (100 percent) recovery for all trace metals, 

except chromium. A slightly low bias is irdicated for 

some constituents (confidence interval doe*7 not 

include 100 percent). Only chromium showed a high 

bias. Standard reference material concentrations of 

chromium may have resulted in a high bias because of 

interelement matrix interference. No adjustments were 

made to the trace element concentrations fcr the insect 

samples on the basis of recovery efficiency.

Results of trace-element analyses of procedural 

blanks for biota are in table 20. Procedural blanks for 

biota consisted of the same reagents used to digest and 

reconstitute tissue of aquatic insects. The thanks were 

analyzed undiluted at a proportion of one blank per site. 

Analytical results for blanks indicated no significant 

contamination bias. With the exception of iron and 

manganese, most concentrations in the blanks were 

below detection levels. The detectable corcentrations 

are within the range of instrument variability and are 

insignificant in relation to the measured corcentrations 

in the insect samples; thus, no adjustments were made 

to trace-element concentrations in biota.

STATISTICAL SUMMARIES OF 

DATA

Statistical summaries of water-quality, bed-sediment, and biological data are provided in tables 21 -24 

for the period of record at each station since 1985. The 

summaries include the period of record, number of 

samples, maximum, minimum, mean, and median of 

concentrations.

Statistical summaries of water-quality data (table 

21) are based on results of cross-sectional samples col12 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
lected periodically by the USGS during the station's 

period of record. They do not include supplemental 

single-vertical samples collected by a contract observer 

at Clark Fork at Turah Bridge and Clark Fork above 

Missoula during 1997 and 1998. Statistical summaries 

of bed-sediment (table 22 and 23) and biological data 

(table 24) are based on results of samples collected 

once-annually during the indicated years. Because not 

all stations were sampled for bed sediment and biota 

every year, these data do not represent a consecutive 

annual record.

Sample sizes and statistics for bed-sediment data 

are based on the annual mean concentrations determined from the combined results of composite samples 

for a given year. Therefore, sample sizes for bed sediment represent the number of years sampled. Sample 

sizes and statistics for biological data are based on individual analyses for each composite sample collected in 

individual years rather than the combined annual mean 

concentration. Biota sample sizes therefore reflect differences in species abundances at each site and among 

all years. The statistics for biota describe the full range 

of trace-element concentrations measured among all 

available composite samples. The abundance of 

aquatic insects at a particular site in a given year limits 

the biomass of the sample which, in turn, may result in 

different taxa analyzed among years or in variable analytical detection limits. Where minimum reporting levels vary among years, statistical summaries are 

provided only as a general indication of the range of 

detection.

The presence or absence of insect species at a 

given site can vary among years and may result in different taxa being analyzed in the long-term period of 

record. Because Hydropsyche insects were not sorted 

to the species level during 1986-89, statistics for stations sampled during those years are based on the 

results of all Hydropsyche species combined. At some 

sites, statistics for the Hydropsyche morosa group are 

based on the combined results for two or more species 

because these samples could not be identified clearly to 

the species, but had morosa characteristics.

REFERENCES CITED

Axtmann, E.V., Cain, D.J., and Luoma, S.N., 1997, Effect 

of tributary inflows on the distribution of trace metals in 

fine-grained sediment and benthic insects of the Clark 

Fork River, Montana: Environmental Science and 

Technology v. 31, p. 750-758.

Axtmann, E.V., and Luoma, S.N., 1991, Large scale

distribution of metal contamination in the fir ^-grained 

sediment of the Clark Fork River, Montana: Applied 

Geochemistry, v. 6, p. 75-88.

Cain, D.J., Luoma, S.N., and Axtmann, E.V., 199",

Influence of gut content in immature aquatic insects on 

assessments of environmental metal contamination: 

Canadian Journal of Fisheries and Aquatic Sciences, v. 

52, no. 12, p. 2736-2746.

Cain, D.J., Luoma, S.N., Carter, J.L., and Ferd, S.V., 1992, 

Aquatic insects as bioindicators of trace element 

contamination in cobble-bottom rivers and streams: 

Canadian Journal of Fisheries and Aquatic Sciences, v. 

49, no. 10, p. 2141-2154.

Dodge, K.A., Hornberger, M.I., and Axtmann, E.V., 1996, 

Water-quality, bed-sediment, and biological data" 

(October 1994 through September 1995) and statistical 

summaries of data for streams in the upper Clark Fork 

basin, Montana: U.S. Geological Survey Op^n-File 

Report 96-432, 109 p.

___1997, Water-quality, bed-sediment, and biological 

data (October 1995 through September 1996) and 

statistical summaries of data for streams in tH upper 

Clark Fork basin, Montana: U.S. Geological Survey 

Open-File Report 97-552, 91 p.

___1998, Water-quality, bed-sediment, and biological

data (October 1996 through September 1997) and 

statistical summaries of data for streams in tH upper 

Clark Fork basin, Montana: U.S. Geological Survey 

Open-File Report 98-407, 102 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., 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 wat°r and 

fluvial sediments: U.S. Geological Survey Techniques 

of Water-Resources Investigations, book 5, chap. Al, 

545 p.

Friedman, L.C., and Erdrnan, D.E., 1982, Quality assurance 

practices for the chemical and biological analyses of 

water and fluvial sediments: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 

5, chap. A6, 181 p.

Guy, H.P., 1969, Laboratory theory and methods for

sediment analysis: U.S. Geological Survey Techniques 

of Water-Resources Investigations, book 5, chap. Cl, 

58 p.

REFERENCES CITED 13
Helsel, D.R., and Cohn, T.A., 1988, Estimation of 

descriptive statistics for multiply censored water 

quality data: Water Resources Research, v. 24, no. 12, 

p. 1997-2004.

Homberger, M.I., Lambing, J.H., Luoma, S.N., and

Axtmann, E.V., 1997, Spatial and temporal trends of 

trace metals in surface water, bed sediment, and biota of 

the upper Clark Fork basin, Montana, 1985-95: U.S. 

Geological Survey Open-File Report 97-669, 84 p.

Horowitz, A.J., Demas, C.R., Fitzgerald, K.K., Miller, T.L., 

and Rickert, D.A., 1994, U.S. Geological Survey 

protocol for the collection and processing of surfacewater samples for the subsequent determination of 

inorganic constituents in filtered water: U.S. 

Geological Survey Open-File Report 94-539, 57 p.

Jones, B.E., 1987, Quality control manual of the U.S. 

Geological Survey's National Water Quality 

Laboratory: U.S. Geological Survey Open-File Report

87-457, 17 p.

Knapton, J.R., 1985, Field guidelines for collection, 

treatment, and analysis of water samples, Montana 

District: U.S. Geological Survey Open-File Report 85- 

409, 86 p.

Knapton, J.R., and Nimick, D.A., 1991, Quality assurance 

for water-quality activities of the U.S. Geological 

Survey in Montana: U.S. Geological Survey Open-File 

Report 91-216, 41 p.

Lambing, J.H., 1987, Water-quality data for the Clark Fork 

and selected tributaries from Deer Lodge to Milltown, 

Montana, March 1985 through June 1986: U.S. 

Geological Survey Open-File Report 87-110, 48 p.

____1988, Water-quality data (July 1986 through 

September 1987) and statistical summaries (March 

1985 through September 1987) for the Clark Fork and 

selected tributaries from Deer Lodge to Missoula, 

Montana: U.S. Geological Survey Open-File Report 

88-308, 55 p.

____1989, Water-quality data (October 1987 through 

September 1988) and statistical summaries (March 

1985 through September 1988) for the Clark Fork and 

selected tributaries from Galen to Missoula, Montana: 

U.S. Geological Survey Open-File Report 89-229,51 p.

____1990, Water-quality data (October 1988 through 

September 1989) and statistical summaries (March 

1985 through September 1989) for the Clark Fork and 

selected tributaries from Galen to Missoula, Montana: 

U.S. Geological Survey Open-File Report 90-168,68 p.

___1991, Water-quality and transport characteristics of 

suspended sediment and trace elements in streamflow 

of the upper Clark Fork basin from Galen to Missoula, 

Montana, 1985-90: U.S. Geological Survey WaterResources Investigations Report 91-4139, 7~ p.

Lambing, J.H., and Dodge, K.A., 1993, Quality assurance 

for laboratory analysis of suspended-sediment samples 

by the U.S. Geological Survey in Montana: U.S. 

Geological Survey Open-File Report 93-131, 34 p.

Lambing, J.H., Hornberger, M.I., Axtmann, E.V., and

Dodge, K.A., 1995, Water-quality, bed-sediment, and 

biological data (October 1993 through September 

1994) and statistical summaries of data for steams in 

the upper Clark Fork basin, Montana: U.S. Geological 

Survey Open-File Report 95-429, 104 p.

Lambing, J.H., Hornberger, M.I., Axtmann, E.V., and Pope, 

D.A., 1994, Water-quality, bed-sediment, arH 

biological data (October 1992 through September 

1993) and statistical summaries of water-qurlity data 

(March 1985 through September 1993) for streams in 

the upper Clark Fork basin, Montana: U.S. Geological 

Survey Open-File Report 94-375, 85 p.

Luoma, S.N., and Bryan, G.W., 1981, A statistical 

assessment of the form of trace metals in oxidized 

estuarine sediments employing chemical ext-actants: 

Science of the Total Environment, v. 17, p. 167-196.

Porterfield, George, 1972, Computation of fluvial-sediment 

discharge: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 3, chap. C3, 

66 p.

Pritt, J.W., and Raese, J.W., eds., 1992, Quality 

assurance/quality control manual National Water 

Quality Laboratory: U.S. Geological Survey Open-File 

Report 92-495, 33 p.

Rantz, S.E., and others, 1982, Computation of discharge: 

U.S. Geological Survey Water-Supply Paper 2175,2 v., 

631 p.

Taylor, J.K., 1987, Quality assurance of chemical

measurements: Chelsea, Mich., Lewis Publishers, 

328 p.

Timme, P.J., 1994, National Water Quality Laboratory 1994 

Services Catalog: U.S. Geological Survey C ^en-File 

Report 94-304, 103 p.

U.S. Geological Survey, 1977, National handbook of 

recommended methods for water-data acquisition-- 

Chap. 5, Chemical and physical quality of water and 

sediment: Office of Water Data Coordination, 193 p.

Ward, J.R., and Harr, C.A., eds., 1990, Methods for

collection and processing of surface-water and bedmaterial samples for physical and chemical analyses: 

U.S. Geological Survey Open-File Report 90440,71 p.

14 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
DATA

DATA 15
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998

[Abbreviations: ft3/s, cubic feet per second; °C, degrees Celsius; e, estimated; ng/L, micrograms per liter; nS/cm, microsiemens per centimeter at 25 °C; 

mg/L, milligrams per liter; mm, millimeter; ton/d, tons per day. Symbols: <, less than minimum reporting level; --, no data]

12323230-BLACKTAIL CREEK AT HARRISON AVENUE, AT BUTTE, MONT.

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

01...

12...

'29...

Jun

26...

Aug

21...

Time

1005

1030

1120

1130

1145

0930

0750

1010

Streamflow, Specific pH, Temper- Hardness, Calcium 

instan- conductance, onsite ature, total .. . ! 

taneous onsite (standard water (mg/L as (man \ 

(frVs) (nS/cni) units) (°C) CaCO3) lmg/M

8.4 271 7.8 3.5 110 30

7.6 290 7.9 4.0 120 32

17 254 7.8 4.0 97 28

28 187 7.8 8.0 72 21

21 207 7.8 13.5 84 24

20 220 7.9 8.5 90 26

44 198 7.8 11.5 83 24

6.1 316 7.8 11.5 130 36

Magnesium, 

dissolved 

(mg/L)

7.2

8.4

6.8

5.0

5.9

6.3

5.7

8.7

Arsenic, 

total 

recoverable

(M8/L)

3

3

5

7

5

7

11

4

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

01...

12...

'29...

Jun

26...

Aug

21...

Arsenic, 

dissolved

2

2

4

4

4

5

7

3

CaSm' Cadmium, Co^ Copper, J ' 

recoverable dissolved recoverable dissolved recoverable

(Mg/L) (^g/L) (Mg/L) <^L> (Mg/L)

<1 0.5 4 2 570

<1 .1 2 1 320

<1 <1 6 3 930

<1 <1 9 5 1,300

<1 <1 6 4 730

<1 <1 6 4 630

<1 <1 12 7 1,200

<1 <1 2 1 260

Iron, 

dissolved

(Mg/L)

160

61

420

480

290

280

350

44

Lead, 

total 

recoverable

(M8/L)

<1

<1

1

2

1

<1

3

<1

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

01...

12...

'29...

Jun

26...

Aug

21...

Lead, 

dissolved

(Mg/L)

<0.6

<6

.6

<6

<6

<6

<6

<.6

~ 

M°S' M»x a ,£*- «^-a dssd -w WL) &>

60 42 <10 <10 7

50 38 <10 <10 3

60 40 ^10 <10 9

50 27 <10 <10 17

50 36 <10 <10 11

50 43 <10 <10 10

70 38 10 <10 28

40 32 <10 <10 4

Sediment 

discharge, 

suspended 

(ton/d)

0.16

.06

.41

1.3

.62

.54

3.3

.07

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

80

86

88

80

82

79

66

82

16 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued) 

12323250--SILVER BOW CREEK BELOW BLACKTAIL CREEK, AT BUTTE, MONT.

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

01...

12...

'29...

Jun

26...

Aug

21...

Streamflow, Specific ^ .? Temper- Hardness, ^ . , 

T. instan- conductance, °n,s''e ature, total SSZi 

Time taneous onsite <*£ water (mg/L as d "jjj1 

(fWs) (nS/cm) °* (°C) CaCO3 ) 1 8/M

1145 24 470 7.6 7.0 150 43

1130 22 505 7.7 6.5 160 45

0930 40 464 7.5 6.0 160 44

0920 42 354 7.7 9.0 120 35

1010 38 394 7.6 10.5 130 38

0750 39 393 7.8 9.5 140 41

1010 73 335 7.8 11.5 120 35

1040 24 535 7.6 14.0 180 52

Magne- Arsenic, 

sium, total 

dissolved recoverable

(mg/L) (Mg/L)

11 21

12 9

11 8

8.3 12

9.4 10

9.8 19

8.1 13

13 8

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

01...

12...

'29...

Jun

26...

Aug

21...

Arsenic. C"JS] ' Cadmium, CJW?r' Copper, Iron, 

TiEf recoverable **$* recoverable d*»* * recoverable

'MCT / VM-S* "/ vMw .)

8 2 .9 150 19 2,000

521 82 20 650

444 89 77 640

621 68 34 2,300

6 1 1 55 29 600

8 3 1 110 34 5,800

821 82 32 1,300

7 2 2 47 21 250

Iron, ttttA

Mg/ O'S'L)

44 45

42 11

150 6

250 11

100 12

110 28

210 15

20 3

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

01...

12...

'29...

Jun

26...

Aug

21...

 _ , Mane a- Zinc, Zinc, c. ,, . Lead, nese, » f f .' Hl«nlv«i Sediment, 

dissolved total H- i H w awsolved suspended

(Mg/L) recoverable Tu^n ""Tu^U (m8/L)

(Hg/L) (fig/L) (fig/L)

<.6 500 390 480 320 71

<.6 470 430 470 370 16

1 630 620 960 920 12

.9 440 360 430 370 51

.6 370 360 380 330 13

1 650 480 650 420 405

1 370 350 460 360 28

<6 480 470 570 520 6

£££. 2S3S

suspended a *L <tnn/it\ nn^r tnan

4.6 82

.95 84

1.3 85

5.8 85

1.3 89

43 86

5.5 94

.39 86

TABLE 4 17
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12323600-SILVER BOW CREEK AT OPPORTUNITY, MONT.

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

01...

12...

28...

Jun

26...

Aug

21...

Streamflow, Specific 

T. instan- conductance, 

taneous onsite

(frVs) (pS/cm)

1305 52 429

1300 39 527

1335 65 447

' 1320 104 294

1340 83 330

1800 98 341

1135 140 305

1245 31 535

onsite Temper- Hardness, Cj 

(stan- atur , tai {j.j

dard /o/-\ f^rr\ \ (' units) ( C) CaC03 )

8.6 4.5 150

8.5 4.0 170

8.5 5.0 160

8.4 12.5 110

8.5 12.0 120

8.2 16.0 130

8.2 11.0 110

8.5 17.5 190

dcium< ^um6" Sodium' Sfm," 

^,ye, dissolved /~~/i\ dissolved 

 «/L> (mg/L) (m8/L) (nrg/L)

45 10

48 12

46 10 23 4.8

31 6.6 14 3.3

37 7.6 15 3.5

38 8.1

33 7.0

55 13

Sulfate, 

dissolved

(mg/L)

--

--

89

51

55

--

--

--

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

01...

12...

28...

Jun

26...

Aug

21...

Chloride, Fluoride, Silica, 

dissolved dissolved dissolved 

(mg/L) (mg/L) (mg/L)

..

..

16 .5 26

8.7 .3 23

9.7 .3 22

..

-

Arsenic, \r* fnic Cadmium,

total dissolved t0tal recoverable , ,, - recoverable

(Hg/L) ^lg/lj) (Mg/L)

14 7 2

17 8 2

16 7 3

21 9 1

15 9 1

18 9 2

27 10 2

19 9 2

Cadmium, C»PPJr< Copper, 

dSLf recoverable di(s^'1

1 140 43

1 200 37

2 160 47

<1 130 36

.5 100 30

.9 140 39

1 260 84

2 230 65

Iron, 

total 

recoverable

780

1,200

990

1,500

740

980

1,900

470

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

01...

12...

28...

Jun

26...

Aug

21...

Iron, \JJJ Lead, 

dSlL)d recoverable djjjj|{jd

24 17 <6

10 30 <6

17 22 .6

61 31 1

26 16 <6

46 29 1

120 58 2

12 14 .6

"a" /",%, St\

^(M^g/L) C (Mg/L) (Mg/L)

550 500 460

720 630 610

700 670 660

370 259 350

330 280 270

420 380 400

480 380 620

670 620 540

Zinc' «oHim<> n» Sediment 

dissolved SU sp ded d'scn*"^ 

le (/ig/L) / /i \ suspended Ung/L) (ton/d)

280 17 2.4

340 26 2.7

420 21 3.7

143 62 17

120 23 5.2

190 32 8.5

320 76 29

250 10 .84

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

86

95

91

63

83

79

61

84

18 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12323750-SILVER BOW CREEK AT WARM SPRINGS, MONT.

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

05...

12...

27...

Jun

26...

Aug

21...

Time

1355

1350

1510

0950

1510

1720

1245

1450

Stream flow, 

instantaneous

(ft3/!)

77

67

95

207

192

249

292

48

Specific 

conductance, 

onsite

(US/cm)

517

568

506

372

358

315

343

475

pH,

onsite 

(standard 

units)

8.3

8.7

9.0

8.8

8.8

9.1

8.9

9.0

Temper- Hardness, raicium Magne- Sodium 

ature, total MI^ slum' iu i^J 

water (ing/Las d *S°,f dissolved ^jJu 

(°C) CaCO3) * & (mg/L) * v '

5.0 210 61 15

4.0 240 67 17

7.0 210 60 14 19

12.0 140 40 9.3 15

15.0 140 40 9.4 15

12.5 130 38 8.3

11.5 140 43 8.7

17.5 210 60 14

Potasj slum, 

dissolved 

(mg/L)

--

--

4.4

3.6

3.1

--

--

-

Sulfate, 

dissolved 

(mg/L)

-

--

130

88

83

-

--

--

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

05...

12...

27...

Jun

26...

Aug

21...

Chloride, 

dissolved 

(mg/L)

--

--

12

8.8

8.5

--

--

--

Fluoride, 

dissolved 

(mg/L)

-

--

.8

.6

.5

-

-

-

Silica, 

dissolved 

(mg/L)

--

--

12

13

13

--

-

--

Arsenic, 

total 

recoverable

17

13

16

31

24

27

29

41

Arsenic, Ct^T' Cadmium, C<W > 

dissolved vi«* dissolved ivn« ^

(Hg/L) (Mg/L)

17 <1 <1 8

10 <1 .2 11

14 <1 <.l 24

21 <1 <.l 25

20 <1 <1 16

23 <1 <1 19

27 <1 <1 12

39 <1 <1 10

Copper, 

dissolved

4

8

9

10

9

7

8

5

Iron, 

jcoverable

160

140

310

620

250

490

280

140

Date

Nov 1997

03...

Mar 1998

11...

Apr

14...

May

05...

12...

27...

Jun

26...

Aug

21...

Iron, 

dissolved

(WJ/L)

<5

<5

8

21

16

24

21

<5

Lead, 

total 

recoverable

1

<1

3

5

2

3

1

1

Lead, 

dissolved

(Mg/L)

<.6

<6

<6

<6

.8

<6

<6

<.6

Manganese, 

total 

recoverable

60

190

210

160

110

110

210

160

Manga- Zinc, Zinc, ««.«... .,* 

nese, total dissolved "^ 

dissolved recoverable (Mg/L) / P»/i ^ 

(^g/L) (Mg/L) W& <m«/L>

32 20 <10 4

160 40 15 5

120 50 <10 8

63 30 13 28

55 20 <10 12

32 30 <10 19

160 20 <10 10

58 20 <10 6

Sediment 

discharge, 

suspended 

(ton/d)

.83

.90

2.1

16

6.2

13

7.9

.78

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

93

51

86

88

89

85

83

90

TABLE 4 19
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12323770--WARM SPRINGS CREEK AT WARM SPRINGS, MONT.

Date

Nov 1997

03...

Apr 1998

14...

May

12...

27...

Jun

26...

Aug

21...

Streamflow, Specific 

T,_ instan- conductance, 

"me taneons onsite

(ft3/*) (|aS/ctn)

1415 97 318

1450 46 370

1445 103 230

1750 130 180

1345 263 175

1515 16 415

''site Temper- Hardness, p

<ss 52 <# 

aara ,opv CmCO-i " units) ( C) *-*-"3)

8.5 4.5 150

8.5 5.5 180

8.4 10.5 1 10

8.2 10.0 86

8.2 9.0 83

8.5 15.5 200

jcinm' ^r s?*i?m>t Kr

»<*!** dlwolved d "2rf dluohtd 

"S7^ (mf/L) (mg/L) (mg^,)

46 9.1

54 11 3.8 1.5

34 6.3 2.2 .9

27 4.7

26 4.6

61 11

Sulfate, 

dissolved 

(mg/L)

~

54

21

»

~

-

Date

Nov 1997

03...

Apr 1998

14...

May

12...

27...

Jun

26...

Aug

21...

Chloride, Fluoride, Silica, 

dissolved dissolved dissolved 

(mg/L) (mg/L) (mg/L)

1.3 .4 10

.7 .3 9.1

..

_

Arsenic, Arsenic. Cadmium,

"* « dteoKed total KI recoverable (ua/L) recoverable

(Mg/L) \tf> > (ng/L)

4 3 <1

4 3 <1

5 3 <1

7 3 <1

8 5 <1

7 7 <1

Cadmium, C?o^T' Copper, 

dissolved «oiai dissolved 

(Mg/L) nC^mn » (Mg/L) tMt/Li;

<.l 7 1

<.l 6 4

<.l 14 3

<.l 23 4

<1 27 4

<.l 4 2

Iron, 

total 

recoverable

(M8/L)

110

90

250

390

480

40

Date

Nov 1997

OSApr 1998

14...

May

12...

27...

Jun

26...

Aug

21...

Iron, total Lead, 

dissolved « m dissolved

8 <1 <.6

6 <1 <.6

8 2 <.6

11 4 <.6

12 3 <.6

<5 <1 <.6

* IVlAngft- Zinc*

ncSC, -,*-* *H*«i tntal nese, totu

recoverabk "l"0,1^ r«over«l)

/tia/i \ lMg/Ll' vM8/M (Mg/Li;

150 130 <10

190 170 <10

110 66 <10

120 65 10

90 49 20

200 190 <10

Zlnc' Sedi ent Sedime''t 

dkuolvcd H.v«v>' vw SIIBDCIHICQ diiCnAr^^. » »* j -j

^* (MS''-') SM«./I \ suspciMi^d 

^^ (ton/d^

<10 6 1.6

<10 8 .9?

<10 19 5.3

<10 24 8.4

<10 30 21

<10 2 .0?

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

82

70

63

76

72

75

20 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12323800-CLARK FORK NEAR GALEN, MONT.

Date

Nov 1997

03...

Mar 1998

11...

Apr

15...

May

05...

12...

28...

Jun

26...

Aug

21...

Stream flow, Specific 

Tim. Instaii- conductance, 

1 ' taneoui oniite 

(ft3/!) (MS/cm)

1535

1455

0745

1050

1635

0700

1520

1320

170 419

124 476

158 471

303 332

293 314

342 278

533 270

62 477

°""* TaturT" "'totaf*' Calcium, "Jage- ^^ FJJ8.9 5.0 190 55 13

8.6 6.0 210 61 14

8.6 4.0 210 61 13 15 3.4

8.5 12.0 140 40 8.6 11 2.9

8.7 14.0 130 38 8.3 10 2.4

8.8 8.0 120 36 7.4

8.7 12.0 110 35 6.7

8.8 17.0 210 63 13

Sulfate,

-

-

110

66

62

-

-

-

Date

Nov 1997

03...

Mar 1998

11...

Apr

15...

May

05...

12...

28...

Jun

26...

Aug

21...

Chloride, 

dissolved 

(mg/L)

-

-

8.7

6.0

5.5

-

-

-

Fluorlde, Silica, 

dissolved dissolved 

(mg/L) (mg/L)

_

_

.7 12

.4 12

.5 11

..

_

..

A!^|IC' Ar«ni«. C*l7!lim' Cadmium, C°PPfr' Copper, 

recoverable *Jg* recoverable *"jj« readable *"Jj- , 

(M8/L) (MB''-') (Hg"L)

10 10 <1 <.l 9 3

8 8 <1 <.l 10 6

12 10 <1 <1 21 8

25 16 <1 <.l 55 8

18 15 <1 <.l 20 7

20 18 <1 <.l 23 6

22 18 <1 <.l 28 7

31 31 <1 <.l 10 5

Iron, 

recoverable

120

140

320

840

300

450

550

110

Date

Nov 1997

03...

Mar 1998

11...

Apr

15...

MAY

OS...

12...

28...

Jun

26...

Aug

21...

Iron, 

dissolved

(Mf/L)

4

<5

11

14

14

21

16

<5

Lemd' Lead,

recoverable / ?* 

(Mg/L) «I«'L>

<1 <.6

<1 <.6

2 <6

7 <.6

3 <.6

3 <6

3 <6

1 .6

M_-5*" Manga- Zinc, Zinc, c^««..* Sediment 

totol dm' total «Hi«olved jjjJSEi «H«h«rge,

"^ V/ii^ WW*- * (M8/L) (Mg/L) (ton/d) 1 )

90 70 <10 <10 5 2.3

200 160 20 10 4 1.3

250 170 40 <10 8 3.4

260 65 50 <10 44 36

120 51 20 <10 17 13

130 44 30 <10 20 18

160 83 30 <10 26 37

130 64 10 <10 7 1.2

impended 

(percent

0.062 mm)

87

90

87

79

76

75

65

76

TABX £ 4 21
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12324200--CLARK FORK AT DEER LODGE, MONT.

Date

Nov 1997

03.,

Mar 1998

11...

Apr

15...

May

OSIS.,

28.,

Jun

29.,

Aug

21...

Stream flow, Specific 

-p, instan- conductance, 

taneous onsite 

(ft3/*) (nS/cm)

1715 351 458

1610 252 485

0905 277 500

1220 384 385

0750 292 360

0845 443 330

0840 728 347

1655 86 516

(stan- a * (tne/L as dissolved rf'ssolTed dissolved dis'ored 

dard /o^>\ *~> *~>f\ \ (mg/L) / /» * (m£/L) / /. \ units) * * CaCO3 ) v w ' (mg/L) v * ' (ng/L)

8.6 5.0 210 60 14

8.6 5.0 220 63 15

8.2 4.5 220 64 14 15 3.3

8.3 13.5 160 47 10 12 3.0

8.1 11.5 150 44 9.5 12 2.8

8.2 9.5 140 42 9.1

8.2 12.5 150 45 9.4

8.5 17.0 220 66 14

9?

-

-

100

73

65

-

-

-

Date

Nov 1997

03.,

Mar 1998

11.,

Apr

15...

May

05.,

13...

28.,

Jun

29.,

Aug

21...

Chloride, Fluoride, Silica, 

dissolved dissolved dissolved 

(mg/L) (mg/L) (mg/L)

..

..

8.3 .7 15

6.3 .5 14

6.4 .5 14

..

..

A tS!!d C' Arsenlc' Cadmi"m< Cadmium, C°pp?r' Copper, 

recoverable * §* recoverable dj»°l*«d recoverable ^^

10 9 <1 <1 12 4

10 7 <1 <1 21 5

13 9 <! <1 29 7

25 14 <1 <! 79 11

!9 14 <1 <.! 41 10

28 19 <1 <! 90 9

20 16 <1 .1 56 12

20 !9 <! <! !0 6

recoverable

200

330

430

1,400

510

1,400

840

70

Date

Nov 1997

03...

Mar 1998

11...

Apr

15...

May

05.,

13.,

28.,

Jun

29.,

Aug

21...

Iron, t'fal* Lead, 

dissolved erable dissolved

8 1 <.6

<5 2 <6

8 4 <6

8 11 <6

11 5 <6

17 11 <6

17 6 <6

<5 <1 <.6

Manga- Manga- Zinc, Zinc, c .. . Sedi-nent 

nese. ** . . , .. , ' j sediment, JI..L total nese, total dissolved susoended discharge, 

. , dissolved recoverable (uc/L) , ,, , suspended recoverable / u \ / n \ (mg/L) .r , j-> /,, /! \ (HS/L) (Hg/L) " (ton/d) (jag/L;

60 29 20 <10 10 9.5

90 50 30 <10 18 12

110 44 40 <10 2! 16

240 23 80 15 69 72

130 28 40 <10 25 20

210 25 80 <10 76 91

130 26 50 <10 39 77

40 24 <10 <10 5 1.2

(percent 

finer than

80

74

63

68

79

67

66

81

22 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON, MONT.

Date

Nov 1997

04...

Apr 1998 

15...

May 

13...

28...

Jun

29...

Aug 

21...

nH Streamflow, Specific J* .' Temper- Hardness, r . . MagneT. instan- conductance, ?n.slre ature, total j. , """.' sium, 

llme taneous onsite <*"" water (mg/L as dissolved dissolved 

(fr/s) (nS/cm) °**° (°C) CaCO3) l mg/M (mg/L)

1110 105 275 8.4 12.0 120 36 8.1

1035 146 240 8.4 4.0 110 32 7.4

0915 282 186 8.1 9.0 86 25 5.9

1120 332 207 8.2 9.5 97 28 6.5

1100 515 213 8.2 11.5 96 28 6.5

1745 68 273 8.5 16.5 120 36 8.2

Arsenic, 

tctal 

recoverable

5

4

5

5

6

6

Date

Nov 1997

04...

Apr 1998 

15...

May 

13...

28...

Jun

29...

Aug 

21...

Arsenic, Cadmium, Cadmium, C°PPer' Copper, Iro"l' Iron, 

dissolved ,. dissolved . dissolved torai dissolved 

. ,. ^ recoverable , / , recoverable . ,, -. recoverable , ,,-.

4 <1 <1 1 <1 90 7

4 <1 <1 1 1 180 33

4 <1 <.l 2 2 300 27

5 <1 <.l 2 <I 260 28

5 <1 <1 2 2 340 44

6 <1 <.l <1 <1 40 <5

Lead, 

tital 

recoverable

<1

<,

<}

<\

<l

<j

Date

Nov 1997

04...

Apr 1998 

15...

May

13...

28...

Jun

29...

Aug 

21...

, . Manga- Manga- Zinc, Zinc, «... . Sediment 

Lead, nese, | ,' dissolved Sediment, discharee 

dissolved total dissolved recoverable (oJlT suspended susoended (ug/L) recoverable , ,, » , ,, . ^"^ (mg/L) suspen ea / _/i \ (Ug/L) (Mg/L) * v ' (ton/d)

<6 20 5 <10 <IO 4 1.1

<6 20 7 10 <IO 6 2.4

<6 30 10 <IO <IO 16 12

<6 20 9 <10 <10 14 13

<6 20 11 <10 <10 19 26

<6 10 9 <10 <10 4 .73

Secfiment, 

suspended 

(percent 

finer than 

0.0^?. mm)

97

85

74

69

63

72

TABLE 4 23
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12324680--CLARK FORK AT GOLDCREEK, MONT.

Date

Nov 1997

04...

Mar 1998

12...

Apr

16...

May

05...

13...

28...

Jun

29...

Aug

24...

Streamflow, Specific 

Ti instan- conductance, 

taneous onsite 

(frVs) (MS/cm)

1020 562 427

0840 416 442

0845 513 421

1455 903 286

1020 661 287

1330 1,010 290

1240 1,620 297

0920 281 435

£** TaTureer" "iS"* Calcium' 

(*ta"- water (mg/L as *l%??f dard ,0r\ rarr> \ (mg/L) units) ( C) CaCO.,)

8.5 5.5 190 56

8.3 2.0 200 58

8.3 4.0 190 54

8.4 14.5 120 35

8.3 11.5 120 36

8.4 11.5 130 37

8.3 14.0 130 38

8.3 14.5 190 55

Magnesium, 

dissolved 

(mg/L)

13

13

12

7.7

8.C

8.2

8.3

11

Arsenic, 

total 

recoverable

(MS/L)

8

10

10

17

12

18

14

13

Date

Nov 1997

04...

Mar 1998

12...

Apr

16...

May

05...

13...

28...

Jun

29...

Aug

24...

Arsenic, Cadmium, Cadmium, 

dissolved . , dissolved ( e/L} recoverable , ,, ^ W (Mg/L) W

8 <1 <1

6 <1 <1

8 <1 <1

9 <1 <1

9 <1 <1

11 <1 <.l

10 <1 <1

11 <1 <.l

Copper, rnniwr Ir°"'

total d led total recoverable , r,\ recoverable

(Mg/L) ^*** ' (Mg/L)

14 3 220

29 6 410

21 5 350

43 7 1,200

35 6 470

67 8 1,100

38 8 780

12 4 190

Iron, 

dissolved

(Mg/L)

<5

6

7

18

13

14

24

<5

Lead, 

total 

recoverable

(Hg/L)

2

3

3

7

4

9

6

1

Date

Nov 1997

04...

Mar 1998

12...

Apr

16...

May

05...

13...

28...

Jun

29...

Aug

24...

"n'eT NT' 

dissolved total .. , '. "*" > W w$

<.6 60 21

<.6 100 41

<.6 80 25

.8 150 14

<.6 80 13

<.6 140 13

<6 100 17

<.6 60 10

total dissolved j j ui in \ suspended recoverable (W5/L) , /. -.

(Mg/L) WlM

20 <10 10

40 <10 24

30 <10 18

50 -^10 65

30 <10 25

60 <10 61

40 <10 43

10 <10 11

Sediment 

discharge, 

suspended 

(ton/d)

15

27

25

158

45

166

188

8.3

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

90

81

78

70

77

68

61

87

24 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data frr streams in the 

Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12331500--FLINT CREEK NEAR DRUMMOND, MONT.

Date

Nov 1997

04...

Mar 1998

12...

Apr

16...

May

05...

13...

28...

Jun

29...

Aug

24...

Streamflow, Specific JI.iL Temper- Hardness, r . . 

Tin,, * - conductance, °D.s"e ature, total £J£S 

llme taneous onsite (!""' water (mg/L as Jl? /IT 

(ft5/.) (MS/cm) d*rtd (°C) CaC03) (mg/L)

0910 183 308 8.3 5.0 140 38

0950 111 299 8.5 2.0 140 37

1005 159 285 8.3 4.0 130 35

1630 274 162 8.4 13.5 70 19

1145 119 214 8.5 10.0 99 27

1540 231 236 8.5 13.5 110 31

1430 818 219 8.1 14.0 100 28

1015 41 469 8.4 12.0 210 58

Magnesium, 

dissolved 

(mg/L)

12

12

11

5.3

7.6

8.3

7.8

17

Arsenic, 

total 

recoverable

(ug/L)

8

9

9

26

12

15

19

10

Date

Nov 1997

04...

Mar 1998

12...

Apr

16...

May

05...

13...

28...

Jun

29...

Aug

24...

Arsenic, Cadmium, Cadmium, C°PPer' Copper, J"* 

,. . _ total i. i j total i. j total dissolved .. dissolved »«" dissolved »«»» « 

, ^.} recoverable , ^.* recoverable , ... recoverable (MS/L) ^ (Mg/L) ()ig/L)

6 <1 <1 2 <1 230

5 <1 <1 3 <1 290

5 <1 <1 3 1 480

7 <1 <.l 9 2 1,000

6 <1 <1 3 1 390

8 <1 <1 4 1 440

16 <1 <.l 5 3 650

11 <1 <.l 2 <1 100

Iron, 

dissolved

10

7

44

50

19

21

57

14

Lead, 

total 

recoverable

(Mg/L)

4

5

4

18

8

9

6

<1

Date

Nov 1997

04...

Mar 1998

12...

Apr

16...

May

05...

13...

28...

Jun

29...

Aug

24...

i _ . *" Manga- Zinc. Zinc, e ji_ ^ Lead, nese, " *»t»i ^v.^i LJ Siediinent,

dissolved total J^ recoverable US? sus'>ended 

(Mg/L) recoverable SL) (^L) (m»/L)

(Mg/L)

<6 70 19 10 <10 13

<.6 100 28 20 <10 20

<.6 90 21 20 <10 28

.7 260 22 50 <10 78

<.6 110 22 20 <10 24

<6 130 20 20 <10 39

<.6 170 23 30 <10 41

<.6 100 84 <10 <10 5

Sediment 

discharge, 

suspended 

(ton/d)

6.4

6.0

12

58

7.7

24

91

.55

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

82

86

82

68

86

63

66

80

TABLE 4 25
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12331800--CLARK FORK NEAR DRUMMOND, MONT.

Date

Nov 1997

04...

Mar 1998

12...

Apr

16...

May

06...

13...

Jun

02...

29...

Aug

24...

Streamflow, Specific P ,1 Temper- Hardness, r . . 

T- P instan- conductance, °"si'e ature, total £«,,,' 

Tlme taneous onsite (* ta"' water^ (mg/L as d "so Jf 

(ft3/!) OiS/cm) J J (°C) CaC03 ) lmg/b>

0750 884 437 8.4 5.0 200 55

1055 593 457 8.5 4.5 210 58

1130 758 422 8.3 7.0 190 54

0810 1,200 300 8.1 12.0 130 37

1310 817 331 8.4 13.5 150 42

0845 1,220 367 8.3 12.0 160 47

1600 3,170 303 8.2 16.0 140 40

1150 406 519 8.4 16.5 230 67

Magne- Arsenic, 

sium, total 

dissolved recoverable 

(mg/L) (Mg/L)

14 9

15 9

13 10

8.5 19

10 11

11 14

9.3 20

16 13

Date

Nov 1997

04...

Mar 1998

12...

Apr

16...

May

06...

13...

Jun

02...

29...

Aug

24...

Arsenic, Cadmium, Cadmium, C°PP'r' Copper, J "'

*"£?» -ovtrable *«**« recoverable *"£? recoverable (Mg/L) / ,, , (Mg/L) , ,, , (Mg/L) , ,, , (J^g/M (Mg'L') (.Mg'L')

8 <1 <1 12 3 230

7 <1 <.l 17 4 300

7 <1 <1 18 4 400

9 <1 <1 46 7 1,300

10 <1 <1 23 6 380

12 <1 <1 30 7 610

15 <1 .2 57 9 1,600

13 <1 <.l 9 4 130

^ue/L) recoverable

<5 2

<5 2

9 3

22 11

8 4

11 5

32 10

<5 <1

Date

Nov 1997 

04...

Mar 1998

12...

Apr

16...

May

06...

13...

Jun

02...

29...

Aug

24...

i _ _ Manga- Zinc, Zinc, c- _ , Lead, nese, » . dissolved Sediment, 

dissolved total .. . e' . hi aissoivea suspended

(Mg/D reco^rable "JJ «"J«« " (mg/L)

<6 60 12 20 <10 11

<.6 70 25 30 <10 20

.6 80 21 30 <10 33

<6 190 10 80 <10 79

<6 70 15 30 <10 21

<.6 100 10 40 <10 40

<6 160 22 90 <10 115

<6 50 12 10 <10 10

£££ «

"(twT jgj26 90

32 76

68 53

256 74

46 84

132 66

984 58

11 85

26 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams In the 

Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12334510--ROCK CREEK NEAR CLINTON, MONT.

Date

Nov 1997

05...

Apr 1998

16...

May

13...

Jun

02...

30...

Aug

24...

Streamflow, Specific J| .1 Temper- Hardness, r . . 

Time ,instan- conductance, Jjj ature, total ^"j 

taneous onsite l . . water (mg/L as , ,. . 

(fP/s) (MS/cm) « (»C) CaC03 ) (mg/L)

0920 337 134 8.0 3.5 59 15

1255 367 129 8.2 6.0 62 16

1620 1,760 67 8.0 9.0 32 8.3

1045 1,550 79 8.0 8.5 37 9.8

1150 1,900 94 8.0 12.5 43 11

1255 355 134 8.4 13.5 61 16

Magnesium, 

dissolved 

(mg/L)

5.1

5.5

2.7

3.2

3.5

5.2

Arsenic, 

total 

recoverable

(Mg/L)

<1

<1

<1

<1

<1

<1

Date

Nov 1997

05...

Apr 1998

16...

May

13...

Jun

02...

30...

Aug

24...

Arsenic, Cadmium, Cadmium, C°We. r' Copper, I "'

dissolved u, dissolved u, dissolved u, t ,, > recoverable , _,. . recoverable , ,, Y recoverable

<^L) (Mg/L) <W^L> (Mg/L) <^L> (nB/L)

<1 <1 <1 <1 <1 60

<1 <I <1 <\ <1 80

<1 <1 <1 1 <1 180

<1 <I <1 1 <1 140

<1 <1 <1 2 <l 200

<1 <1 <I <\ <1 70

Iron, 

dissolved

(Mg/L)

15

16

36

35

50

11

Lead, 

total 

recoverable

(Mg/L)

<1

<1

<1

<1

<1

<1

Date

Nov 1997

05...

Apr 1998

16...

May

13...

Jun

02...

30...

Aug

24...

Manga- Manga- Zinc, Zinc, So .. f Lead, nese, " . . . ,. . , Sediment, ts? A <£* A tsr -asr

<.6 <10 3 <10 <10 2

<.6 <10 2 <10 <10 4

<.6 <IO 2 <10 <IO 13

<.6 10 2 <10 <IO 9

<6 <10 3 <10 <10 13

<.6 <10 4 <10 <10 4

Sediment 

discharge, 

suspended

(ton/d)

1.8

4.0

62

38

67

3.8

Pediment, 

suspended 

(percent 

Pier than 

0.062 mm)

85

78

58

63

58

79

TABLE 4 27
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12334550--CLARK FORK AT TURAH BRIDGE, NEAR BONNER, MONT.

_ 

Date

Nov 1997

05...

Mar 1998

12...

Apr

16...

May

06...

207...

209...

2 11...

14...

224...

Jun

02...

2 19...

221...

222...

223...

225...

227...

230...

30...

Aug

25...

. 

Time

 _ -

1045

1300

1515

1050

1045

0845

0830

0930

0810

1230

1800

0845

1100

0930

1440

1100

0645

1410

0915

__ 

Streamflow, 

instantaneous 

(frVs)

_ - 

1,310

880

1,350

3,110

3,130

3,340

3,090

2,630

3,500

3,050

4,440

7,160

6,390

6,010

5,980

7,240

5,420

5,200

796 

_ - 

Specific 

conductance, 

onsite

(US/cm)

 - 

361

379

340

182

179

172

175

181

207

224

228

236

227

222

231

231

230

233

351 . . .- - 

pH, 

onsite 

(standard 

units)

8.4

8.5

8.5

8.1

8.0

7.8

7.9

8.1

7.9

8.4

8.1

8.0

8.1

8.1

8.1

8.0

8.1

8.2

8.3 ______._ - . ..-! ' '

- . ~ 

Temperature, 

water (°C)

5.5

5.0

7.5

11.0

13.0

10.0

10.0

9.5

10.0

11.0

11.0

12.0

15.0

12.0

14.0

11.0

14.0

16.5

14.0 _ 

i ' "

Hardness, 

total 

(mg/L as 

CaC03)

 - - - 

160

170

150

77

75

74

75

80

91

99

98

100

98

99

100

100

100

100

160 _ - 

___ ' 

Calcium, 

dissolved 

(mg/L)

« ' 

46

49

43

22

21

21

21

22

26

28

28

29

28

28

29

29

29

30

44 _ - 

_ - 

Magne- Arsenic, 

slum, total 

dissolved recoverable 

(mg/L) (H8/L)

_ _ 

12

13

11

5.5

5.4

5.3

5.4

5.9

6.4

7.2

7.1

7.3

6.9

7.0

7.3

7.3

7.3

7.4

11 ' 

6

6

7

10

9

11

7

5

14

8

17

26

19

16

14

23

13

12

7

28 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued) 

12334550-CLARK FORK AT TURAH BRIDGE, NEAR BONNER, MONT. (Continued)

Date

Nov 1997

05...

Mar 1998

12...

Apr

16...

May

06...

207...

209...

2 11...

14...

224...

Jun

02...

2 19...

2 21

222...

223...

225...

227...

230...

30...

Aug

25...

Arsenic, 

dissolved

(M8/L)

6

5

5

4

4

4

4

4

6

6

7

11

10

8

8

10

8

8

6

Ca?o7aT Cadnj , C^ 

recoverable }SS°/L\ recoverable ((ig/L) ^** ' (ng/L)

<1 <1 8

<1 <1 15

<1 <.l 14

<1 <.l 30

<1 <1 30

<1 <1 30

<1 <1 22

<1 ^.1 11

<1 <1 73

<1 <1 16

<1 .2 82

<1 <1 160

<1 <.l 83

<1 <1 64

<1 .3 27

<1 <1 95

<1 <1 42

<1 <1 31

''I <1 5

Copper, 

dissolved

(Mg/L)

3

5

4

4

6

5

4

3

8

4

7

17

11

9

9

13

7

7

2

Iron, 

total 

recoverable

150

160

280

1,000

1,200

1,100

690

300

1,700

390

2,400

4,000

2,200

1,700

880

3,200

1,100

870

100

Iron, 

dissolved

<5

<5

8

33

26

23

21

23

29

18

17

54

37

39

20

39

23

32

<5

Lead, 

total 

recoverable

<1

2

2

6

6

6

4

2

10

2

13

23

12

9

4

16

6

5

<1

TABLE 4 29
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued) 

12334550--CLARK FORK AT TURAH BRIDGE, NEAR BONNER, MONT. (Continued)

Date

Nov 1997

05...

Mar 1998

12...

Apr

16...

May

06...

207...

209...

2 11...

14...

224...

Jun

02...

2 19...

221

222...

223...

225...

227...

230...

30...

Aug

25...

Lead, 

dissolved

(Hg/L)

<6

<6

<6

<.6

<.6

<6

<6

<.6

<6

<.6

<6

<6

<6

<.6

<6

<6

<.6

<6

<6

Manganese, 

total 

recoverable

40

40

50

130

110

100

90

40

190

50

240

440

210

170

90

330

130

100

30

Manganese, 

dissolved

4

11

10

7

<2

<2

<2

6

<2

6

<2

3

3

4

<2

2

4

16

6

Zinc, Zinc, 

total dissolved 

recoverable (Mg/L)

10 <10

20 <10

20 <10

50 <10

50 <10

50 <IO

40 <IO

20 <10

90 <10

20 <10

140 <10

230 <10

120 <10

90 <10

40 <10

170 <10

60 <10

50 <IO

<10 <10

Sediment, 

snspended 

(mg/L)

8

12

15

81

89

102

53

22

127

28

214

312

163

132

127

250

78

60

8

Sediment 

discharge, 

snspended 

(ton/d)

28

29

55

680

752

920

442

156

1,200

231

2,570

6,030

2,810

2,140

2,050

4,890

1,140

842

17

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

89

82

81

59

_

-

-

65

-

65

-

_

_

_

_

..

-

69

87

30 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12340000-BLACKFOOT RIVER NEAR BONNER, MONT.

Date

Nov 1997

05...

Apr 1998

17...

May

06...

14...

Jun

02...

30...

Aug

25...

Stream flow, Specific p ,! Temper- Hardness, ~ , . 

T. install- conductance, ?n.slte ature, total S2£S 

Time taneous onsite <sta"- water (mg/L as <"«olved 

(ft3/*) (pS/cm) 3JJ (°C) CaC03) <mg/L)

1255 854 265 8.7 6.0 140 34

0800 1,220 206 8.3 6.0 100 27

1430 4,300 152 8.2 11.0 73 19

1130 3,260 160 8.3 10.0 80 2i

1400 3,570 185 8.4 11.5 91 23

1620 4,050 210 8.4 15.5 110 28

1 115 786 264 8.6 15.0 130 32

Magnesium, 

dissolved 

(mg/L)

12

9.2

6.2

6.9

7.9

8.9

12

Arsenic, 

total 

recoverable

(Mg/L)

1

<1

i

<i

1

1

1

Date

Nov 1997

05...

Apr 1998

17...

May

06...

14...

Jun

02...

30...

Aug

25...

Arsenic, Cadmium, Cadmium, CoPPfr' Copper, '"".' 

dissolved total dissolved total dissolved tottl liS? recoverable d 8S recoverable **ff recoverable

(Mg/L) (Mg/L) (Mg/L)

1 <I <.l <\ <I 50

1 <1 <I 1 <I 140

<1 <1 <.l 2 <1 400

<1 <1 <I I <I 130

1 <1 <.I 1 <I 190

1 <I <.l 2 1 360

I <I <l <I <I 50

Iron, 

dissolved

(Mg/L)

<5

15

12

10

10

17

<5

Lead, 

total 

recoverable

(Mg/L)

<1

<1

<1

<1

<1

<i

<1

Date

Nov 1997

05...

Apr 1998

17...

May

06...

14...

Jun

02...

30...

Aug

25...

Lead, "I."?" Ma"f- ZI "<: -JJg, Sediment, 

dissolved total ^""."L, total K, delved .nspended 

(Mg/L) recoverable dj^f "^jg* ^^ ("g/M

<,6 <10 <2 <10 <iO 3

<6 20 4 <10 <10 10

<.6 40 2 <10 <IO 33

<6 10 2 <10 <10 11

<,6 20 2 <IO <10 15

<6 30 4 <IO <10 28

<.6 <IO 2 <IO <10 3

Sediment 

discharge, 

suspended 

(ton/d)

6.9

33

383

97

145

306

6.4

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

90

85

87

90

91

92

85

TABLE 4 31
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12340500--CLARK FORK ABOVE MISSOULA, MONT.

Date

Nov 1997

05...

Mar 1998

12...

Apr

17...

May

06...

207...

209...

2 11...

14...

224,.

Jun

02...

2 19...

221 222~:

223...

2 25...

2 27...

2 30...

30...

Aug

25...

Time

1515

1515

1000

1430

1200

1005

1030

1310

0945

1500

1930

1020

1230

1050

1605

1230

0810

1820

1315

Streamflow, 

instantaneous

(^/t)

2,030

1,460

2,610

7,670

7,620

7,730

6,990

6,070

7,780

6,810

8,700

12,600

11,600

10,700

9,890

11,800

9,350

8,960

1,620

Specific 

conductance, onsite

(US/cm)

318

336

275

165

165

160

~

173

190

201

212

224

218

217

223

225

222

221

297

pH, 

onsite 

(standard 

units)

8.4

8.5

8.3

8.2

8.0

7.8

~

8.2

8.0

8.4

8.1

8.1

8.2

8.2

8.1

8.1

8.1

8.3

8.5

Temperature, 

water (*C)

5.5

5.0

6.5

11.5

13.0

11.0

11.0

10.0

10.0

11.5

12.0

12.0

14.0

14.0

14.0

12.0

14.0

16.0

16.5

Hard nets, 

total 

(mg/L as 

CaCOj)

150

150

130

74

76

73

76

81

85

94

98

100

99

100

100

100

. 100

100

140

Calcium, 

dissolved 

(mg/L)

41

42

35

20

21

20

21

22

23

25

27

27

27

27

28

28

28

29

36

Magnesium, 

dissolved

(mg/L)

12

12

10

5.9

5.9

5.7

6.0

6.4

6.7

7.5

7.6

7.8

7.7

7.9

8.0

8.1

8.0

8.0

11

Arsenic, 

total 

recoverable

4

4

4

5

4

4

4

3

6

4

8

15

11

10

9

12

8

7

4

32 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12340500--CLARK FORK ABOVE MISSOULA, MONT. (Continued)

Date

Nov 1997

05...

Mar 1998

12...

Apr

17...

May

06...

207...

209...

2 ll...

14...

224...

Jun

02...

2 19...

22l

222...

223...

225...

227...

230...

30...

Aug

25...

Arsenic, 

dissolved

(Mg/L)

4

4

3

2

3

2

3

2

3

3

4

8

5

5

5

6

6

5

4

Cadmium, Cadmium, C«WT' 

total HI«««I oH total 

recoverable /,!«/M recoverable

(Mg/L) WIO (nf/L)

<i <.l 5

<l <.l 6

<l <.l 8

<l <.i 14

<1 <.l 14

<l <.l 15

<l <.l 12

<l <.l 8

<i <.l 22

<1 <.l 10

<l <.l 32

<i <.l 75

<l <.l 42

<l <.l 35

<l <.l 27

<l <.l 120

<1 <.l 43

<l <.l 22

<l <l 3

Copper, 

dissolved

2

2

2

2

3

3

2

2

4

2

4

9

6

5

5

8

4

4

2

Iron, 

total 

recoverable

(Mg/L)

100

90

210

600

650

640

470

260

760

310

1,500

2,700

2,200

1,600

1,000

1,800

1,800

670

80

Iron, 

dissolved

(Mg/L)

<5

<5

13

23

18

16

13

17

19

19

18

38

28

32

16

29

22

22

<5

Lead, 

total 

recoverable

(W5/L)

<1

<i

2

3

3

2

2

2

3

1

6

12

8

7

4

9

7

3

<l

TABLE 4 33
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1997 through September 1998 (Continued)

12340500--CLARK FORK ABOVE MISSOULA, MONT. (Continued)

Date

Nov 1997

05...

Mar 1998

12...

Apr

17...

May

06...

207...

209...

2 11...

14...

224...

Jun

02...

2 19...

221

222...

223...

225...

227...

230...

30...

Aug

25...

MangaLead, nese, 

dissolved total 

(Hg/L) recoverable

<.6 30

<.6 40

<.6 60

<.6 70

<.6 60

<.6 60

<.6 50

<.6 30

<.6 80

<.6 40

<.6 140

<.6 260

<.6 184

<.6 150

<.6 100

<.6 180

<.6 170

<.6 70

<.6 30

Manganese, 

dissolved

12

28

37

22

<2

<2

<2

14

<2

13

<2

2

2

4

<2

2

5

17

15

Zinc, Zinc, 

total dissolved 

recoverable (ng/L) 

(Mg/L)

10 <10

10 <IO

10 <IO

20 II

20 <IO

20 <10

20 <IO

10 <IO

30 <10

20 <IO

50 <10

120 <10

70 <10

60 <IO

50 <10

80 <10

70 <10

40 <10

<IO <10

Sediment, 

suspended 

(mg/L)

5

5

12

40

37

36

26

18

42

21

96

194

154

113

70

120

52

45

6

Sediment 

discharge, 

suspended 

(ton/d)

27

20

85

828

761

751

491

295

882

386

2,260

6,600

4,820

3,260

1,870

3,820

1,310

1,090

26

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

93

91

92

90

..

-

-

89

-

92

-

..

-

84

90

'Sample for May 29, 1998, was collected during excavation activities in the stream channel a short distance upstream of sampling location. 

Supplemental samples collected to better define metals transport through Milltown Reservoir during extended high-water runoff.

34 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1997 through September 1998 

[Abbreviations: ft'/s, cubic feet per second; e, estimated; mg/L, milligrams per liter; ton/d, tons per day. Symbol: , no data]

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/*)

279

281

277

280

292

319

325

366

353

340

356

366

352

349

350

341

330

324

323

323

318

309

322

338

338

342

347

346

345

343

370

10,244

330

370

277

Suspended sediment

Mean 

concentration 

(mg/L)

October

12

15

14

14

12

11

12

18

17

16

15

14

13

II

10

9

9

9

9

9

9

9

9

9

10

12

13

14

15

16

20

12

20

9

Discharge 

(ton/d)

9.0

11

10

II

9.5

9.5

11

18

16

15

14

14

12

10

9.5

8.3

8.0

7.9

7.8

7.8

7.7

7.5

7.8

8.2

9.1

11

12

13

14

15

20

344.6

II

20

7.5

Mean 

streamflow

(ft3/*)

374

353

349

351

351

344

340

342

345

343

324

315

320

306

295

300

297

310

320

323

323

323

319

326

337

330

338

331

332

333

9,894

330

374

295

Suspended sediment

Mean 

concentration 

(mg/L)

1997

November

17

12

10

10

10

10

10

10

10

10

11

12

19

27

31

28

23

19

15

13

13

13

13

13

13

13

13

13

13

13

--

_

15

31

10

Discharge 

(ton/d)

17

11

9.4

9.5

9.5

9.3

9.2

9.2

9.3

9.3

9.6

10

16

22

25

23

18

16

13

11

II

11

II

11

12

12

12

12

12

12

-

382.3

13

25

9.2

Mean 

streamflow

(ft3/*)

334

325

288

303

290

285

281

278

281

271

268

267

270

278

269

279

295

299

274

278

286

273

266

278

269

252

259

251

273

284

272

8,676

280

334

251

Suspended sedfment

Mean 

concentration 

(mg/L)

December

13

14

16

23

27

28

28

28

28

28

27

26

25

24

24

28

30

29

28

26

24

23

22

21

20

20

23

42

63

59

49

_

28

63

13

Discharge 

(V>n/d)

12

12

12

19

21

22

21

21

21

20

20

19

18

18

17

21

24

23

21

20

19

17

16

16

15

14

16

28

46

45

36

650

21

46

12

TABLE 5 35
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1997 through September 1998 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(frVs)

277

289

299

298

299

277

287

291

e260

e220

e200

e!90

e200

e220

234

228

273

296

306

309

299

287

280

283

282

278

277

279

274

277

272

8,341

269

309

190

Suspended sediment

Mean 

concentration

(mg/L)

January

40

34

31

27

23

20

18

21

27

31

33

34

36

37

37

37

36

35

35

34

34

33

33

32

32

32

30

27

25

24

23

31

40

18

Discharge 

(ton/d)

30

27

25

22

19

15

14

16

19

18

18

17

19

22

23

23

27

28

29

28

27

26

25

24

24

24

22

20

18

18

17

684

22

30

14

Mean 

streamflow 

(»*/ )

255

268

267

276

271

267

273

289

278

276

277

267

269

267

264

266

263

266

260

260

263

270

263

258

262

260

255

241

...

...

--

7,451

266

289

241

Suspended sediment

Mean 

concentration 

(mg/L)

1998

February

21

20

19

19

20

23

28

29

24

20

17

17

17

17

17

18

18

18

19

19

19

18

17

17

16

16

16

18

...

...

...

...

19

29

16

Discharge 

(ton/d)

14

14

14

14

15

17

21

23

18

15

13

12

12

12

12

13

13

13

13

13

13

13

12

12

11

11

11

12

...

--

...

386

14

23

11

Mean 

streamflow

(ft3/!)

264

262

269

269

260

254

252

250

261

258

254

264

287

300

316

331

348

334

307

284

279

300

333

360

357

350

340

331

313

304

308

9,199

297

360

250

Suspended sediment

Mean 

concentration 

(mg/L)

March

21

20

20

18

18

21

29

25

25

23

22

22

41

52

47

69

65

38

34

32

36

47

46

67

52

43

31

31

25

23

24

34

69

18

Discharge 

(ton/d)

15

14

15

13

13

14

20

17

18

16

15

16

32

42

40

62

61

34

28

25

27

38

41

65

50

41

28

28

21

19

20

888

29

65

13

36 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1997 through September 1998 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

M1N

Meau 

streamflow 

(ft3/*)

300

298

291

289

295

303

333

334

323

306

305

294

296

286

279

277

276

269

261

258

255

253

257

290

322

305

296

288

283

294

...

8,716

291

334

253

Suipeuded sediment

Mean 

concentrator 

<mg/L)

April

26

26

23

32

24

24

37

36

31

25

29

22

24

19

15

19

15

21

23

16

22

31

25

47

51

36

25

20

19

24

-

_

26

51

15

Discharge 

(toa/d)

21

21

18

25

19

20

33

32

27

21

24

17

19

IS

II

14

II

15

16

II

15

21

17

37

44

30

20

16

15

19

-

624

21

44

II

Mean 

stresntflow 

(ft3/*)

317

323

348

380

373

368

385

402

3%

377

360

333

299

298

278

251

247

239

221

210

201

331

464

439

410

415

465

429

341

335

392

10,627

343

465

201

Suspended sediment

Mean 

cencentratioii 

(mg/L)

1998

May

23

39

51

63

61

50

45

64

57

47

37

26

25

18

14

14

12

13

8

8

14

57

116

57

58

48

83

67

26

34

58

...

42

116

8

Discharge 

(ton/d)

20

34

48

65

61

50

47

69

61

48

36

23

20

14

II

9.5

8.0

8.4

4.8

4.5

7.6

51

14S

68

64

54

104

78

24

31

61

1,329.8

43

145

4.5

Mean 

streamflow 

(ft3/!)

354

324

328

336

322

300

313

363

353

341

377

384

465

531

531

539

662

646

725

1,050

883

803

808

835

834

1,000

968

818

706

628

._

17,527

584

1,050

300

Suspended sediment

Mean 

concentration 

(mg/L)

June

36

24

15

12

13

11

15

21

18

19

23

24

45

70

62

54

71

63

95

172

115

62

51

55

70

79

60

39

37

28

-

49

172

11

Discharge 

(toa/d)

34

21

13

II

II

8.9

13

21

17

17

23

25

56

100

89

79

127

110

186

488

274

134

III

124

158

213

157

86

71

47

_

2,824.9

94

488

8.9

TABLE 5 37
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1997 through SeptemHr 1998 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(tf/s)

656

674

814

1,090

909

784

696

619

621

586

665

622

561

497

454

398

338

304

275

237

217

199

189

167

167

152

126

150

264

211

194

13,836

446

1,090

126

Suspended sediment

Mean 

concentration 

(mg/L)

July

48

60

105

106

33

22

21

20

19

19

26

16

19

13

8

6

6

6

6

6

5

5

4

4

3

3

3

20

118

49

21

26

118

3

Discharge 

(ton/d)

85

109

231

312

81

47

39

33

32

30

47

27

29

17

9.8

6.4

5.5

4.9

4.5

3.8

2.9

2.7

2.0

1.8

1.4

1.2

1.0

8.1

84

28

11

1,298.0

42

312

1.0

Mean 

streamflow

(ft3/*)

174

159

155

141

151

159

176

153

137

134

142

112

97

92

89

86

86

93

91

85

85

90

102

105

109

109

105

106

103

102

110

3,638

117

176

85

Suspended sediment

Mean 

concentration 

(mg/L)

1998

August

19

20

16

13

22

17

11

9

8

7

5

6

4

4

3

3

3

4

6

5

4

5

8

9

7

6

5

5

5

5

5

...

8

22

3

Discharge 

(ton/d)

8.9

8.6

6.7

4.9

9.0

7.3

5.2

3.7

3.0

2.5

1.9

1.8

1.0

.99

.72

.70

.70

1.0

1.5

1.1

.92

1.2

2.2

2.6

2.1

1.8

1.4

1.4

1.4

1.4

1.5

89.13

2.9

9.0

.70

Mean 

streamflow

(ft3/*)

116

114

110

106

106

105

108

116

128

169

198

187

172

160

155

151

153

156

153

164

175

174

175

178

184

199

202

204

207

225

...

4,750

158

225

105

Suspended sediment

Mean 

concentration 

(mg/L)

September

5

5

5

5

5

4

5

7

13

23

29

27

24

22

19

17

14

12

11

12

14

19

19

15

15

16

19

20

20

20

...

_

15

29

4

Discharge 

(ton/d)

1.6

1.5

1.5

1.4

1.4

1.1

1.5

2.2

4.5

10

16

14

11

9.5

8.0

6.9

5.8

5.1

4.5

5.3

6.6

8.9

9.0

7.2

7.5

8.6

10

11

11

12

-

204.6

6.8

16

1.1

TOTAL FOR WATER YEAR 1998:

STREAMFLOW-112,899 ft^s 

SEDIMENT D1SCHARGE--9J05.33 tons

38 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1997 through 

September 1998

[Abbreviations: frVs, cubic feet per second; e, estimated; mg/L, milligrams per liter; ton/d, tons per day. Symbol: , no data]

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

M1N

Mean 

streamflow

(frVs)

1,120

1,120

1,150

1,190

1,240

1,260

1,350

1,410

1,440

1,430

1,370

1,390

1,370

1,330

1,320

1,320

1,320

1,300

1,290

1,270

1,260

1,240

1,220

1,250

1,250

1,230

1,250

1,250

1,250

1,270

1,430

39,890

1,287

1,440

1,120

Suspended sediment

Mean 

concentration 

(mg/L)

October

7

7

7

8

8

8

9

12

14

13

11

9

8

7

7

7

7

7

6

6

5

5

6

6

6

6

6

6

6

7

15

...

8

15

5

Discharge 

(ton/d)

21

21

22

26

27

27

33

46

54

50

41

34

30

25

25

25

25

25

21

21

17

17

20

20

20

20

20

20

20

24

58

855

28

58

17

Mean 

streamflow

(ft3/*)

1,580

1,440

1,350

1,330

1,300

1,280

1,260

1,240

1,240

1,240

1,200

1,110

1,100

1,090

999

991

1,020

1,140

1,130

1,130

1,120

1,120

1,090

1,100

1,140

1,120

1,080

1,110

1,090

1,060

-

35,200

1,173

1,580

991

Suspended sediment

Mean 

concentration 

(mg/L)

1997

November

18

10

9

8

8

8

7

6

5

5

5

4

4

4

5

5

5

5

5

6

6

6

6

6

6

6

5

5

5

5

-

6

18

4

Discharge 

(ton/d)

77

39

33

29

28

28

24

20

17

17

16

12

12

12

13

13

14

15

15

18

18

18

18

18

18

18

15

15

15

14

-

619

21

77

12

Mean 

streamflow 

(ft3/*)

1,080

1,060

963

874

913

900

911

976

1,030

957

926

873

891

904

979

973

1,020

1,010

939

874

900

891

859

845

852

802

819

830

936

1,010

956

28,753

928

1,080

802

Suspendel sediment

Mean 

concentration 

(mg/L)

December

5

4

4

3

3

3

3

4

9

8

5

4

4

4

5

7

8

7

6

5

4

3

2

2

2

2

2

3

10

9

9

5

10

2

Discharge

(ton/d)

15

11

10

7.1

7.4

7.3

7.4

11

25

21

13

9.4

9.6

9.8

13

18

22

19

15

12

9.7

7.2

4.6

4.6

4.6

4.3

4.4

6.7

25

25

23

382.1

12

25

4.3

TABLE 6 39
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1997 through 

September 1998 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

II

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/*)

916

990

967

944

912

896

844

903

896

e600

e500

e500

e550

e700

e900

ei,IOO

el, 200

el, 250

el, 150

1,230

1,000

927

897

892

947

935

955

945

892

887

931

28,156

908

1,250

500

Suspended sediment

Mean 

concentration 

(mg/L)

Jannnry

9

9

8

8

8

8

8

8

7

7

6

5

4

4

4

10

37

31

23

18

16

14

12

10

9

8

8

8

8

9

14

11

37

4

Discharge 

(ton/d)

22

24

2i

20

20

19

18

20

17

11

8.1

6.8

5.9

7.6

9.7

30

120

105

71

60

43

35

29

24

23

20

21

20

19

22

35

907.1

29

120

5.9

Mean 

streamflow

(ft3/*)

834

772

804

849

898

876

890

919

921

904

895

879

866

865

846

868

853

845

850

841

859

879

866

831

839

854

829

800

...

...

...

24,032

858

921

772

Suspended sediment

Mean 

concentration 

(mg/L)

1998

February

16

14

12

11

10

11

15

18

18

17

16

15

14

12

11

10

10

10

10

10

10

9

8

8

8

8

8

7

. 

...

...

12

18

7

Discharge 

(ton/d)

36

29

26

25

24

26

36

45

45

41

39

36

33

28

25

23

23

23

23

23

23

21

19

18

18

18

18

15

...

759

27

45

15

Mean 

streamflow 

(ft*/s)

799

864

887

889

865

828

795

781

807

863

858

874

932

1,020

1,090

1,320

1,430

1,280

1,120

1,070

1,090

1,290

1,870

2,610

2,640

2,020

1,790

1,590

1,440

1,340

1,280

38,332

1,237

2,640

781

Suspended sediment

Mean 

concentration 

(mg/L)

March

7

10

12

II

9

8

7

6

9

14

14

12

18

28

38

94

104

67

36

29

32

90

266

403

224

105

59

45

32

26

24

_

59

403

6

Discharge 

(ton/d)

15

23

29

26

21

18

15

13

20

33

32

28

45

77

112

335

402

232

109

84

94

313

1,340

2,840

1,600

573

285

193

124

94

83

9,208

297

2,840

13

40 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for s^ "-earns in the 

Upper Clark Fork Basin, Montana
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1997 through 

September 1998 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/*)

1,290

1.300

1,340

1,430

1.460

1,490

1,550

1.590

1,550

1,510

1,500

1,500

1,470

1,410

1,380

1,350

1.330

1,330

1,300

1,290

1,300

1,350

1,470

1,790

2,140

2.040

1,890

1,840

1,900

2,070

46,160

1,539

2,140

1,290

Suspended sediment

Mean 

concentration 

(mg/L)

April

24

25

26

31

35

32

31

32

30

25

23

23

22

18

15

17

14

16

14

12

13

15

21

47

78

54

39

30

32

46

_

28

78

12

Discharge 

(ton/d)

84

88

94

120

138

129

130

137

126

102

93

93

87

69

56

62

50

57

49

42

46

55

83

227

451

297

199

149

164

257

3,734

124

451

42

Mean 

streamflow

(frVs)

2,250

2,470

2,660

2,910

3,080

3,140

3,170

3,310

3,390

3.240

3,080

2,860

2,710

2,670

2,650

2,460

2,330

2,360

2,190

2,060

2,100

2,660

3,260

3,480

3,240

3,240

3,640

3,670

3,280

3,110

3,380

90.050

2,905

3.670

2,060

Suspended sediment

Mean 

concentration 

(mg/L)

1998

May

54

66

79

116

104

85

75

82

80

57

42

37

30

23

28

21

19

21

17

11

13

40

90

93

54

50

71

67

47

43

47

54

116

11

Discharge 

(ton/d)

328

440

567

9il

865

721

642

733

732

499

349

286

220

166

200

139

120

134

101

61

74

287

792

874

472

437

698

664

416

361

429

13,718

443

911

61

Mean 

streamflow

(frVs)

3,310

3,050

2,910

2,780

2,610

2,510

2,540

2,580

2,540

2,410

2,490

2,580

2,750

3.040

3,270

3,340

3,420

3,840

4,180

6,420

7,000

6,400

6,030

5,970

5,930

6,330

7,180

6,720

5,870

5,3 10

125,310

4,177

7,180

2,410

Suspended rudiment

Mean 

concentration 

(mg/L)

June

47

30

23

21

18

16

23

20

22

17

20

20

23

38

47

45

62

115

142

390

233

132

105

102

102

98

176

115

72

60

-

78

390

16

Discharge 

(ton/d)

420

247

181

158

127

108

158

139

151

111

134

139

171

312

415

406

573

1,190

1,600

6,760

4,400

2,280

1,710

1,640

1,630

1,670

3,410

2,090

1.140

860

34,330

1,140

6,760

108

TAF',E 6 41
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1997 through 

September 1998 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

M1N

Mean 

streamflow 

(ft3/*)

4,980

5,070

4,950

5,650

6,030

5,200

4,510

4,050

3,830

3,620

3,560

3,530

3,160

2,830

2,610

2,410

2,220

2,070

1,930

1,820

1,710

1,640

1,570

1,520

1,480

1,410

1,360

1,340

1,400

1,480

1,590

90,530

2,920

6,030

1,340

Suspended sediment

Mean 

concentration 

(mg/L)

July

54

62

58

132

152

75

57

43

40

38

40

37

32

30

23

19

16

14

9

8

8

8

8

8

8

8

8

8

8

10

17

33

152

8

Discharge 

(ton/d)

726

849

775

2,010

2,470

1,050

694

470

414

371

384

353

273

229

162

124

96

78

47

39

37

35

34

33

32

30

29

29

30

40

73

12,016

388

2,470

29

Mean 

streamflow

(ft3/!)

1,610

1,490

1,410

1,360

1,290

1,230

1,200

1,190

1,140

1,090

1,050

994

934

878

831

813

793

790

785

760

743

758

766

801

780

774

754

736

731

726

714

29,921

965

1,610

714

Suspended sediment

Mean 

concentration 

(mg/L)

1998

August

12

6

6

6

6

6

6

7

7

7

7

7

6

6

6

6

6

5

5

5

4

4

4

14

6

6

6

6

5

5

5

_

6

14

4

Discharge 

(ton/d)

52

24

23

22

21

20

19

22

22

21

20

19

15

14

13

13

13

11

11

10

8.0

8.2

8.3

30

13

13

12

12

9.9

9.8

9.6

518.8

17

52

8.0

Mean 

streamflow

(ft3/s)

703

697

688

676

673

659

655

667

705

732

853

881

854

825

810

797

789

788

797

825

846

849

866

862

862

899

934

925

921

909

23,947

798

934

655

Suspend^ sediment

Mean 

concentration 

(mg/L)

September

6

5

5

5

4

4

5

7

9

12

18

18

13

13

12

12

12

12

13

13

13

13

13

14

14

16

20

18

15

14

...

12

20

4

Discharge 

(ton/d)

11

9.4

9.3

9.1

7.3

7.1

8.8

13

17

24

41

43

30

29

26

26

26

26

28

29

30

30

30

33

33

39

50

45

37

34

-

781.0

26

50

7.1

TOTAL FOR WATER YEAR 1998:

STREAMFLOW--600.281 ft3 /sec 

SEDIMENT DISCHARGE-77,828 tons

42 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1997 through Septenber 1998 

[Abbreviations: frVs, cubic feet per second; e, estimated; mg/L, milligrams per liter; ton/d, tons per day. Symbol: , no data]

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

M1N

Mean 

streamflow 

(ft3/*)

1,890

1,870

1,890

1,930

1,980

2,040

2,060

2,180

2,180

2,180

2,160

2,170

2,100

2,040

2,040

2,040

2,010

2,080

2,040

2,040

2,000

1,950

1,930

1,980

2,050

1,980

1,970

2,000

2,010

2,040

2,300

63,130

2,036

2,300

1,870

Suspended sediment

Mean 

concentration 

(rag/L)

October

5

6

5

4

4

5

6

7

8

7

6

5

5

4

4

4

4

4

4

4

6

5

4

4

4

4

4

4

4

4

7

5

8

4

Discharge 

(ton/d)

26

30

26

21

21

28

33

41

47

41

35

29

28

22

22

22

22

22

22

22

32

26

21

21

22

21

21

22

22

22

43

833

27

47

21

Mean 

streamflow

(frVs)

2,510

2,360

2,200

2,200

2,160

2,110

2,050

2,040

2,040

2,030

1,960

1,820

1,850

1,790

1,590

1,610

1,770

1,930

1,840

1,880

1,900

1,870

1,850

1,810

1,940

1,900

1,860

1,890

1,860

1,810

-

58,430

1,948

2,510

1,590

Suspended sediment

Mean 

concentration 

(mg/L)

1997

November

9

8

6

5

6

5

4

4

4

4

4

3

3

3

4

5

5

4

4

4

3

3

4

4

5

4

3

3

3

4

...

...

4

9

3

Discharge 

(ton/d)

61

51

36

30

35

28

22

22

22

22

21

15

15

14

17

22

24

21

20

20

15

15

20

20

26

21

15

15

15

20

...

700

23

61

14

Mean 

streamflow 

(ft3/!)

1,830

1,810

1,660

1,480

1,510

1,390

1,360

1,550

1,880

1,750

1,700

el, 650

el,600

el, 700

1,870

1,820

1,810

1,760

1,660

1,530

1,590

1,580

1,620

1,680

1,530

1,720

1,690

1,560

1,710

1,880

1,700

51,580

1,664

1,880

1,360

Suspended sediment

Mean 

concentration 

(mg/L)

December

4

4

3

3

3

3

4

5

5

4

4

4

4

4

4

4

5

4

4

3

3

2

2

2

2

2

3

3

4

4

4

4

5

2

Discharge 

(ton/d)

20

20

13

12

12

11

15

21

25

19

18

18

17

18

20

20

24

19

18

12

13

8.5

8.7

9.1

8.3

9.3

14

13

18

20

18

491.9

16

25

8.3

TABLE 7 43
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1997 through Sept°mber 1998 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/!)

1,600

1,730

1,680

1,630

1,580

1,620

1,480

1,530

1,410

el, 000

e800

e900

el, 000

el. 300

el, 500

el, 800

1,890

1,900

1,850

1.870

1.850

1,730

1,630

1,590

1,610

1.580

1,580

1,580

1,480

1,500

1,560

47,760

1,541

1,900

800

Suspended sediment

Mean 

concentration 

<«g/L)

January

4

4

4

4

5

4

4

3

2

2

4

7

8

7

6

5

4

3

4

5

6

5

4

4

3

3

4

5

5

4

3

4

8

2

Discharge

(tOR/d)

17

19

18

18

21

17

16

12

7.6

5.4

8.6

17

22

25

24

24

20

15

20

25

30

23

18

17

13

13

17

21

20

16

13

552.6

18

30

5.4

Mean 

streamflow 

(frVs)

1,420

1,300

1,340

1,430

1,510

1.470

1.490

1,540

1,530

1.500

1,500

1,470

1,450

1,440

1,420

1.450

1.430

1.410

1,420

1.410

1,430

1,470

1.450

1,420

1,400

1,430

1.390

1,360

~

40,280

1.439

1.540

uoo

Suspended sediment

Mean 

concentration 

(«g/L)

IMS

February

3

3

3

3

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

3

3

3

...

-

_

4

4

3

Mscharge

(ton/d)

12

II

II

12

16

16

16

17

17

16

16

16

16

16

15

16

15

15

15

15

15

16

16

15

15

12

II

II

-

410

15

17

II

Mean 

streamflow 

(ft3/*)

1,350

1,430

1,490

1,520

1,460

1,400

1,350

1,330

1,370

1,440

1,430

1,440

1,500

1,630

1.700

2,030

2,270

2,090

1,820

1,780

1,760

1,970

2,740

3,770

4,110

3.420

3,000

2,730

2,520

2,300

2.270

62,420

2,014

4,110

1.330

Suspended sediment

Mean 

concentration 

(mg/L)

March

3

5

7

7

7

5

3

4

4

4

5

5

6

8

8

10

20

21

14

9

8

9

19

55

64

50

29

21

17

16

15

15

64

3

Discharge 

(ton/d)

11

19

28

29

28

19

11

14

15

16

19

19

24

35

37

55

123

119

69

43

38

48

141

560

710

462

235

155

116

99

92

3,389

109

710

11

44 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1997 through September 1998 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/*)

2,270

2,310

2,410

2,550

2,730

2,860

3,050

3,090

3,030

2,970

2,950

2,950

2,910

2,770

2,730

2,670

2,620

2,590

2,510

2,490

2,490

2,540

2,830

3,500

4,460

4,470

4,260

4,170

4,430

4,860

...

92,470

3,082

4,860

2,270

Suspended sediment

Mean 

concentration 

(mg/L)

April

13

11

11

12

13

15

17

16

15

13

14

14

11

11

10

11

12

11

11

10

11

10

14

16

21

20

18

17

16

19

...

_

14

21

10

Discharge 

(ton/d)

80

69

72

83

96

116

140

133

123

104

112

112

86

82

74

79

85

77

75

67

74

69

107

151

253

241

207

191

191

249

-

3,598

120

253

67

Mean 

streamflow 

(ft3 /*)

5,380

5,870

6,270

7,120

7,520

7,650

7,650

7,750

7,850

7,520

7,100

6,560

6,160

6,120

6,030

5,660

5,360

5,560

5,190

4,860

4,910

6,140

7,400

7,700

7,190

7,070

7,870

8,430

7,690

7,180

7,520

208,280

6,719

8,430

4,860

Suspended sediment

Mean 

concentration 

(mg/L)

1998

May

28

31

34

40

43

41

37

34

35

31

26

22

19

18

17

14

14

15

12

9

10

17

29

40

33

25

33

41

30

25

26

...

27

43

9

Discharge 

(ton/d)

407

491

576

769

873

847

764

711

742

629

498

390

316

297

277

214

203

225

168

118

133

282

579

832

641

477

701

933

623

485

528

15,729

507

933

118

Mean 

streamflow 

(ft3/*)

7,370

6,900

6,530

6,220

5,770

5,480

5,430

5,350

5,240

5,000

5,150

5,570

5,740

6,160

6,500

6,670

6,850

7,710

8,370

11,200

12,200

11,800

11,100

10,400

9,910

10,100

11,600

11,200

10,000

9,190

--

236,710

7,890

12,200

5,000

Suspended sediment

Mean 

concentration 

(mg/L)

June

28

23

19

21

17

15

15

17

17

14

15

18

17

22

31

28

27

50

84

226

190

154

112

84

70

72

115

98

65

49

_.

57

226

14

Discharge 

(ton/d)

557

428

335

353

265

222

220

246

241

189

209

271

263

366

544

504

499

1,040

1,900

6,830

6,260

4,910

3,360

2,360

1,870

1,960

3,600

2,960

1,760

1,220

-

45,742

1,520

6,830

189

TABLE? 45
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1997 through September 1998 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/*)

8,570

8.560

8,390

9,130

9,730

8,710

7,940

7,320

6,880

6,600

6,530

6,430

5,930

5,460

5,100

4,750

4,450

4,110

3,870

3,630

3,430

3,180

3,120

3,040

2,870

2,810

2,660

2,610

2,680

2,820

2,930

164,240

5,298

9,730

2,610

Suspended sediment

Mean 

concentration 

(mg/L)

July

46

49

43

66

99

62

43

34

28

27

25

25

25

21

16

12

10

9

9

9

9

8

8

8

7

6

5

4

5

8

11

24

99

4

Discharge 

(ton/d)

1,060

1,130

974

1,630

2,600

1,460

922

672

520

481

441

434

400

310

220

154

120

100

94

88

83

69

67

66

54

46

36

28

36

61

87

14,443

466

2,600

28

Mean 

streamflow

(ft3 /!)

3,020

2,800

2,660

2,530

2,450

2,360

2,280

2,240

2,190

2,080

2,030

1,930

1,810

1,720

1,650

1,590

1,580

1,560

1,540

1,530

1,500

1,510

1,520

1,600

1,610

1,590

1,530

1,500

1,460

1,450

1,440

58,260

1,879

3,020

1,440

Suspended sediment

Mean 

concentration 

(mg/L)

1998

August

8

7

7

6

6

6

5

5

5

5

5

5

5

5

4

4

4

4

4

4

4

4

4

4

5

5

5

5

5

5

5

5

8

4

Discharge 

(ton/d)

65

53

50

41

40

38

31

30

30

28

27

26

24

23

18

17

17

17

17

17

16

16

16

17

22

21

21

20

20

20

19

817

26

65

16

Mean 

streamflow

(ft3/*)

1,420

1,380

1,370

1,340

1,320

1,320

1,260

1,320

1,370

1,380

1,490

1,560

1,530

1,470

1,420

1,400

1,370

1,380

1,370

1,430

1,380

1,450

1,450

1,410

1,440

1,460

1,500

1,510

1,480

1,450

42,430

1.414

1,560

1,260

Suspend Hi sediment

Mean 

concentration 

(mg/L)

September

6

5

5

5

4

4

4

4

4

4

7

8

7

6

5

5

5

5

5

4

4

4

4

4

4

4

4

4

5

5

...

5

8

4

Discharge 

(ton/d)

23

19

18

18

14

14

14

14

15

15

28

34

29

24

19

19

18

19

18

15

15

16

16

15

16

16

16

16

20

20

553

18

34

14

TOTAL FOR WATER YEAR 1998:

STREAMFLOW-1,125,990 ft3/s 

SEDIMENT DISCHARGE-87,258.5 tons

46 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for steams in the 

Upper Clark Fork Basin, Montana
Table 8. Chemical and suspended-sediment analyses of field replicates for water samples, upper Clark Fork basin, Montana 

[Abbreviations: jig/L, micrograms per liter; mg/L, milligrams per liter; mm, millimeter. Symbols: <, less than minimum reporting level; , no data]

Station 

number

12323770

12324200

12324590

12324680

12324680

12334550

12340500

Station name

Warm Springs Creek at Warm Springs

Clark Fork at Deer Lodge

Little Blackfoot River near Garrison

Clark Fork at Goldcreek

Clark Fork at Turah Bridge, near Bonner

Clark Fork above Missoula

Date

06-26-98

06-26-98

03-11-98

03-11-98

05-28-98

05-28-98

04-16-98

04-16-98

05-06-98

05-06-98

08-25-98

08-25-98

05-14-98

05-14-98

Time

1345

1350

1610

1615

1120

1125

0845

0850

1050

1055

0915

0920

1310

1315

Hardness, 

total 

(mg/L as 

CaCO3)

83

83

220

220

97

97

190

190

77

81

160

150

81

81

Calcium, 

dissolved 

(mg/L)

26

26

63

63

28

28

54

54

22

23

44

43

22

22

Magnesium, 

dissolved

(mg/L)

4.6

4.6

15

14

6.5

6.6

12

12

5.5

5.8

11

11

6.4

6.5

Arsenic, 

total 

recoverable

(Mg/L)

8

8

10

9

5

5

10

10

10

10

7

7

3

3

Arsenic, 

dissolved

(Mg/L)

5

5

7

7

5

5

8

7

4

4

6

6

2

2

Station 

number

12323770

12324200

12324590

12324680

12334550

12340500

Cadmium, ,, j -,. Copper,

Date « Cd±vJS' '«'»' recoverable , ., . recoverable

(Mg/L) *" * ' (Mg/L)

06-26-98 <

06-26-98 <

03-11-98 <

03-11-98 <

05-28-98 <

05-28-98 <

04-16-98 <

04-16-98 <

05-06-98 <

05-06-98 <

08-25-98 <

08-25-98 <

05-14-98 <

05-14-98 <

<0.1 27

<1 25

<1 21

<1 22

<1 2

<1 2

<1 21

<1 22

<1 30

<1 30

<1 5

<.l 5

<.l 8

<.l 8

Copper, 

dissolved

(Mg/L)

4

5

5

5

<1

1

5

5

4

5

2

2

2

2

Iron, 

total 

recoverable

(Mg/L)

480

480

330

340

260

250

350

340

1000

1100

100

110

260

250

Iron, 

dissolved

(Mg/L)

12

11

<5

<5

28

27

7

7

33

38

<5

<5

17

18

Lead, 

total 

recoverabfe

(Mg/L)

3

2

2

2

<]

<1

3

3

6

6

<1

<1

2

1

Station 

number

12323770

12324200

12324590

12324680

12334550

12340500

Date

06-26-98

06-26-98

03-11-98

03-11-98

05-28-98

05-28-98

04-16-98

04-16-98

05-06-98

05-06-98

08-25-98

08-25-98

05-14-98

05-14-98

Lead, 

dissolved

(Mg/L)

<0.6

<6

<6

<6

<.6

<6

<6

<6

<6

<.6

<6

^.D

<.o

<6

Manganese, 

total 

recoverable

(Mg/L)

90

100

90

100

20

20

80

80

130

120

30

30

30

30

Manganese, 

dissolved

(Mg/L)

49

49

50

50

9

9

25

25

7

11

6

5

14

14

?t"a7 Zinc' 

recoverable d*sso|1vf1

(Mg/L) <^L>

20 <10

10 <10

30 <10

30 11

<10 <10

<10 <10

30 <10

30 <10

50 <10

60 <10

<10 <10

10 <10

10 <10

10 <10

Sediment, 

suspended

(Mg/L)

30

29

18

17

14

14

18

16

81

79

8

7

18

17

Sediment, 

suspended, 

diameter, 

percent fin »r 

than 0.062 mm

72

74

74

76

69

64

78

78

59

59

87

85

89

88

TABLE 8 47
Table 9. Precision of chemical and suspended-sediment analyses of field replicates for water 

samples, upper Clark Fork basin, Montana

[Abbreviations: ug/L, micrograms per liter; mg/L, milligrams per liter, mm, millimeter]

Constituent and reporting unit

Calcium, dissolved, mg/L

Magnesium, dissolved, mg/L

Arsenic, total recoverable, |ig/L

Arsenic, dissolved, |ig/L

Cadmium, total recoverable, |ig/L

Cadmium, dissolved, ug/L

Copper, total recoverable, |ig/L

Copper, dissolved, |ig/L

Iron, total recoverable, jig/L

Iron, dissolved, ug/L

Lead, total recoverable, |ig/L

Lead, dissolved, |ag/L

Manganese, total recoverable, |ig/L

Manganese, dissolved, |ig/L

Zinc, total recoverable, |ig/L

Zinc, dissolved, ng/L

Sediment, suspended, mg/L

Sediment, suspended, percent finer than 0.062 mm

Number of 

replicate pairs

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

Standard 

deviation, 

in units (+/-)

0.38

.28

.27

.27

.0

.0

.65

.40

27

1.4

.38

.0

4.6

1.1

4.0

.43

.93

1.6

Relative 

standard 

deviation, 

in percent (+/-)

1.0

3.2

3.6

5.2

.0

.0

4.0

6.4

6.8

9.5

17

.0

6.8

4.8

18

7.9

3.6

2.2

48 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 10. Precision of chemical analyses of laboratory replicates for water samples, upper Clark 

Fork basin, Montana

[Abbreviations: jig/L, micrograms per liter; mg/L, milligrams per liter]

Constituent and reporting unit

Calcium, dissolved, mg/L

Magnesium, dissolved, mg/L

Arsenic, total recoverable, |ag/L

Arsenic, dissolved, |ag/L

Cadmium, total recoverable, pg/L

Cadmium, dissolved, jag/L

Copper, total recoverable, ng/L

Copper, dissolved, ng/L

Iron, total recoverable, |ag/L

Iron, dissolved, jag/L

Lead, total recoverable, jag/L

Lead, dissolved, |ag/L

Manganese, total recoverable, \ig/L

Manganese, dissolved, ng/L

Zinc, total recoverable, |ag/L

Zinc, dissolved, ng/L

Number of 

replicate pairs

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

Standard 

deviation, 

in units (+/-)

0.25

.07

.43

.12

.02

.02

.55

.59

2.4

1.4

.17

.07

1.4

.82

1.4

3.3

Relative 

standard 

deviation, 

in percent (+/-)

0.7

.7

6.2

2.6

5.1

7.5

1.9

6.9

.5

3.0

4.0

23

1.1

.8

1.3

6.0

Within limits of 

data-quality 

objective

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

Yes

Yes

Yes

Yes

TABLE 10 49
Table 11. Recovery efficiency for trace-element analyses of laboratory-spiked deionized-water blanks 

[Abbreviation: ng/L, micrograms per liter]

Constituent and reporting unit

Arsenic, total recoverable, |ag/L

Arsenic, dissolved, ^g/L

Cadmium, total recoverable, ng/L

Cadmium, dissolved, ng/L

Copper, total recoverable, ug/L

Copper, dissolved, ug/L

Iron, total recoverable, ng/L

Iron, dissolved, ng/L

Lead, total recoverable, ng/L

Lead, dissolved, ng/L

Manganese, total recoverable, ug/L

Manganese, dissolved, ^g/L

Zinc, total recoverable, ^g/L

Zinc, dissolved, ^ig/L

Number of 

samples

4

4

4

4

4

4

4

4

4

4

4

4

4

4

95-percent 

confidence 

interval for spike 

recovery, 

in percent

99.2-112

87.3-95.7

87.0-108

93.8-114

98.8-108

93.4-107

90.7-113

89.9-102

88.8-121

91.8-109

94.4-111

92.1-106

86.9-116

85.9-104

Mean spike 

recovery, 

in percent

105.4

91.5

97.4

104

103.4

100.4

101.8

95.7

104.8

100.2

102.8

99.0

101.3

95.2

Within limits cf 

data-quality 

objective

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

50 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 12. Recovery efficiency for trace-element analyses of laboratory-spiked stream samples, upper Clark Fork basin, Montana

[Abbreviation: ng/L, micrograms per liter]

Constituent and reporting unit Number of samples

95-percent

confidence interval for

spike recovery,

in percent

Mean spike 

recovery, 

in percent

With'n limits of

da1 "-quality

objective

Arsenic, total recoverable, |Ag/L 

Arsenic, dissolved, |ig/L 

Cadmium, total recoverable, |ig/L 

Cadmium, dissolved, |ig/L 

Copper, total recoverable, ng/L 

Copper, dissolved, \ig/L 

Iron, total recoverable, |ig/L 

Iron, dissolved, |ig/L 

Lead, total recoverable, |ig/L 

Lead, dissolved, |jg/L 

Manganese, total recoverable, jag/L 

Manganese, dissolved, |ig/L 

Zinc, total recoverable, |ig/L 

Zinc, dissolved, |ig/L

95.8-112 

85.5-94.7 

92.7-106 

97.3-112 

88.4-110 

90.6-104 

82.8-112 

90.2-113 

92.9-117 

94.3-110 

85.8-113 

98.0-105 

85.6-112 

89.1-110

104.0

90.1

99.5

104.4

99.1

97.2

97.5

101.8

105.0

102.2

99.5

101.5

98.8

99.5

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes

TABLE 12 51
Table 13. Chemical analyses of field blanks for water samples

[Abbreviations: °C, degrees Celsius; \ig/L, micrograms per liter, uS/cm, microsiemens per centimeter at 25 °C; mg/L, milligrams per liter. 

Symbol: <, less than minimum reporting level]

Specific M..»- Anenlc, r«ims..m 

conduct- JjJJk Calcium, "JjjjJ^ total Anenic, toTal

NOV 1997 

05... 1500 3 5.6 0.02 <0.01 <l <1 <1 

MAR 1998 

12... 0700 3 5.7 <.02 <.01 <1 <1 <1 

APR 

16... 1630 3 5.6 <.02 <.01 <1 <l <1 

MAY 

13,. 1400 3 5.7 <02 <.01 <1 <1 <1 

28... 0950 2 5.5 <.02 <.01 <1 <1 <1 

AUG 

22... 0800 2 5.7 .03 <.01 <1 <1 <1

Cadmium, C<*f*r> 

*l(!£/L) recoverable

<0.1 <1

<.l <1 

<.l <1

^ Mwm* 

Copper, /"""i" Iron, total' Lead, new, Manganese,

(Hg/L) ( n . (Hg/L) * ,, ^ (Mg/L) recoverable (ng/L) (H»M IWM (pg/L)

NOV 1997 

05... <1 <10 <5 <1 <0.6 <10 <2 

MAR 1998 

12., <1 <10 <5 <1 <.6 <10 <2 

APR 

16... <1 <10 <5 <l <.6 <10 <2 

MAY 

13,. <1 <10 <5 <1 <.6 <10 <2 

28., <1 <10 <5 <1 <.6 <10 <2 

AUG 

22., <1 <10 <5 <1 <.6 <10 <2

Zinc, 7i_- total £inc, 

. . d "solved recoverable WVV *i «U *i \U£/H)

<10 <10

52 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, August 1998

[Fine-grained sediment is material less than 0.064 millimeter in diameter. Concentrations are the mean of all analyses for replicate aliquots from each 

composite sample. Abbreviation: ng/g, micrograms per gram of dry sample weight. Symbol: <, less than]

Station number 

(fig. 1)

12323600

12323750

12323800

461415112450801

461559112443301

461903112440701

12324200

12324590

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, 

near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek 

diversion, near Racetrack

Clark Fork at Deer Lodge

Little Blackfoot River near 

Garrison

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, 

near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula 1

Number 

of composite 

samples

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

Concentration, in jag/g

Cadmium

23.7

6.6

6.4

6.8

5.5

4.8

5.5

1.5

4.9

1.8

3.0

.7

4.0

.6

2.3

1.9

Chromium

32.4

34.1

31.2

32.0

30.0

34.1

43.9

52.9

48.9

29.2

34.0

26.1

31.1

25.8

30.6

23.9

Copper

4,220

358

1,090

1,360

946

842

978

78

791

56.4

470

15

413

21

282

156

Iron

41,100

27,200

34,100

32,700

31,700

33,700

35,300

30,700

30,600

25,700

27,000

20,600

24,000

20,200

24,300

20,300

Lead

797

100

145

168

134

115

138

35.6

119

150

99

10

85

12.8

60

41

Manganese

2,590

3,960

5,040

3,980

3,130

2,680

2,240

905

1,770

3,090

1,910

724

2,270

472

1,290

1,490

Nickel

16.1

19.1

19.3

17.8

16.7

16.8

21.1

21.9

18.6

14.6

16.0

13.4

16.3

13.4

15.0

12.8

T'lver

15.2

<3.2

<3.2

4.2

<3.3

3.5

4.3

<1.6

3.2

5.1

<3.2

<1.6

2.4

<-1.6

<3.2

1.6

Zinc

6,990

812

1,230

1,280

1,030

900

1,050

204

1,110

577

939

53

909

62

696

447

Samples collected about 30 miles downstream from water-quality station to conform to previous sampling location.

TABLE 14 53
Table 15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, August 1998

[Bulk bed sediment collected in this study generally is material smaller than about 10 millimeters in diameter. Concentrations are the mean of all a-ralyses for

replicate aliquots for each composite sample. Abbreviation: ug/g, micrograms per gram of dry sample weight. Symbol: <, less than]

Station number 

(fig. 1)

12323600

12323750

12323800

461415112450801

461559112443301

461903112440701

12324200

12324590

12324680

12331500

12331800

12334510

12334550

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek diversion, 

near Racetrack

Clark Fork at Deer Lodge

Little Blackfoot River near Garrison

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, near Bonner

Clark Fork above Missoula

Clark Fork below Missoula 1

Number 

of composite Cadsamples mium

1 4.9

1 .5

1 4.8

1 2.0

1 2.1

1 3.0

1 2.0

1 .7

1 2.0

1 .9

1 <1.6

1 <8

1 2.3

1 <1.6

1 <8

Concentration, in |ig/g

Chromium

11.6

9.2

11.3

13.1

12.7

20.9

20.7

33.2

21.1

11.0

20.1

8.8

23.4

18.2

6.0

Copper

670

20

250

398

375

577

440

20

243

20

196

5

279

129

30

Iron

20,800

7,200

19,500

17,600

17,900

25,400

22,900

21,000

18,300

15,700

16,300

7,270

19,100

16,000

5,830

Lead

231

11

158

78

78

88

82

18

55

96

47

<10

67

30

<10

Manganese

741

722

1,120

1,390

1,680

1,940

1,160

308

1,260

2,580

1,140

265

1,470

553

368

Nickel

6.0

4.8

5.8

6.7

7.3

12.8

12.3

15.2

10.5

5.8

10.4

4.5

12.1

10.3

3.8

Silver

3.5

<1.5

<3.2

<3.5

<3.2

<3.2

<3.2

<1.6

<3.2

3.5

<3.2

<1.6

2.9

<3.3

<1.6

Zinc

1,740

93

677

522

535

604

540

86

623

325

516

17

638

387

83

'Samples collected about 30 miles downstream from water-quality station to conform to previous sampling location.

54 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for st-earns in the 

Upper Clark Fork Basin, Montana
Table 16. Recovery efficiency for trace-element analyses of standard reference materials for bed sediment

[Abbreviations: ng/g, micrograms per gram of dry sample weight; SRM, standard reference material. Symbol: --, recovery could not be detemined because 

all analyses were less than the analytical detection limit for lead and silver]

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number of 

measurements

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

Dilution ratio

1:5

1:5

1:5

1:5

1:5

1:5

1:5

1:5

1:5

1:10

1:10

1:10

1:10

1:10

1:10

1:10

1:10

1:10

Certified concentration

(ng/g)

SRM sample 2709

0.4

130

35

35,000

19

538

88

.4

106

SRM sample 27 11

41.7

47.0

114

28,900

1,160

638

20.6

4.6

350

Mean SRM recovery 

(percent)

132

68.4

86.6

107

--

102

99.7

-

100

102

63.1

95.9

90.5

103

87.1

90.0

91.3

95.4

95-percent confidence 

interval fcr SRM 

recovery 

(percent)

110-153

66.0-70.9

81.3-92.0

105-110

-

99.4-105

97.4-102

--

97.6-103

101-102

61.9-614

94.8-97.0

89.8-91.2

102-103

86.8-87.5

88.6-91.4

83.2-9?.4

95.2-95.7

TABLE 16 55
Table 17. Trace-element analyses of procedural blanks for bed sediment

[Abbreviation: ug/mL, micrograms per milliliter. Dilution ratio is the proportion of initial volume of concentrated nitric acid used as a digesting 

reagent to final volume of solution after addition of 0.6 N hydrochloric acid used for reconstituting dried residue. Symbols: <, less than; --, no data]

Sample 

identification

A

A

B

B

C

C

D

D

E

E

F

F

G

G

H

H

I

1

Dilution 

ratio

1:5

1:10

1:5

1:10

1:5

1:10

1:5

1:10

1:5

1:10

1:5

1:10

1:5

1:10

1:5

1:10

1:5

1:10

Trace-element concentration, in ug/mL

Cadmium

<0.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

Chromium

<0.005

<.005

<.005

<.005

<.005

<.006

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

Copper

<0.005

<.005

<.005

<.005

<.005

<.005

<.005

<.009

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

Iron

0.065

.262

<.015

.026

<.015

.049

<.015

.028

<.015

<.060

<.023

<.109

.015

.063

<.015

.032

<.015

.070

Lead

<0.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

Manganese

<0.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

Nickel

<0.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

<.015

Silver Zinc

<0.01 0.006

<.01 .021

<.01 <.005

<.01 <.005

<.01 <.005

<.01 .016

<.01 <.005

<.01 .013

<.01 <.005

<.01 .017

<.01 <.005

<.01 <.014

<.01 <.005

<.01 .012

<.01 .007

<.01 .034

<.01 <.005

<.01 .014

56 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 1998

[Analyses are of whole-body tissue of aquatic insects. Composite samples made by combining similar-sized insects of the same species into a 

sample of sufficient mass for analysis. Concentrations for biota samples composed of two or more composite samples are the means of all 

analyses. Abbreviations: ug/g, micrograms per gram of dry sample weight. Symbol: <, less than minimum reporting level]

Number of Concentration, in ng/g

Taxon

Brachycentrus spp.

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche cockerelli

Hydropsyche occidentalis 

Hydropsyche occidentalis

Hydropsyche spp.

Hydropsyche cockerelli

Hydropsyche occidentalis 

Hydropsyche occidentalis

Hydropsyche occidentalis 

A rctopsyche grandis

Claassenia sabulosa

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Hydropsyche cockerelli

Arctopsyche grandis

Hydropsyche cockerelli

Hydropsyche occidentalis

posite Cad- Chro- Cop- . 

. . . Iron samples mium mium per

12323600 Silver Bow Creek at Opportunity

1 12.5 1.1 592 363

12323750 Silver Bow Creek at Warm Springs

4 .3 .8 28.7 383

1 <.9 1.7 22.8 483

12323800 Clark Fork near Galen

1 1.5 1.6 49.8 1,160

4 .7 1.3 51.5 1,110 

4614151 12450801 Clark Fork below Lost Creek, near Galen

4 1.0 1.9 58.6 1,120

1 1.4 1.7 67.8 1,200

461559112443301 Clark Fork near Racetrack

1 1.9 2.4 50.5 981

Lead

7.9

2.5

<2.8

<7.5

6.2

7.1

9.7

10.5

3 .7 1.9 65.4 1,440 9.5 

4619031 12440701 Clark Fork at Dempsev Creek diversion, near Racetrack

4 .8 1.9 82.7 1,550

12324200 Clark Fork at Deer Lodge

4 1.0 2.1 86.3 1,660 

12324590 Little Blackfoot River near Garrison

1 .6 1.6 11.2 654

1 .5 .9 36.1 319

1 .3 2.3 15.2 1,340

12324680 Clark Fork at Coldcreek

3 2.3 1.0 35.8 548

1 1.7 .4 43.6 84.6

1 1.3 2.0 61.4 1,340

2 1.4 1.8 63.4 1,310

12331500 Flint Creek near Drummond

3 .1 2.0 11.9 1,450

1 <1.6 4.0 18.1 3,290

12331800 Clark Fork near Drummond

1 3.0 1.6 54.7 898

1 2.0 2.9 72.6 1,860

2 1.2 2.1 69.7 1,570

11.7

11.3 

<3.5

<1.2

2.3

3.4

<1.3

5.8

6.3

5.1

16.3

6.2

12.8

9.1

Manganese

357

762

1,200

1,760

1,990 

2,130

1,980

1,530

2,080 

2,300

1,690 

533

71

554

765

50.6

774

1,020

959

1,230

1,190

982

1,170

Nickel

<1.0

.3

1.8

1.2

.9 

1.0

1.4

1.3

1.1 

1.4

1.4 

.4

.6

1.1

.6

<4

1.8

1.9

1.2

2.2

1.1

1.8

1.2

Zinc

687

16.4

150

180

171 

188

186

179

211 

230

218 

179

202

137

185

270

168

196

161

181

215

202

202

TA BLE 18 57
Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 1998 (Continued)

Taxon

Number o 

composite 

samples

f

Cad- Chromium mium

Concentration, in |ag/g

Cop- , Iron 

per

Lead

Manganese

Nickel Zinc

12334510 Rock Creek near Clinton

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche spp. 

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

3

1

.2 1.3

<4 .5

11.3 774

33.9 106

1 <2.9 2.1 11.6 1,140 

12334550 Clark Fork at Turah Bridge, near Bonner

4

2

2

2

1.7 1.9

1.4 .6

1.1 1.9

.9 1.8

40.5 1,190

75.6 136

46.9 1,240

47.8 1,150

.7

.6

<2.9 

5.2

1.3

5.7

5.4

320

39.0

462

724

114

602

662

1.0

.2

1.9 

1.1

<.2

1.2

1.0

143

184

126 

211

232

163

174

12340000 Blackfoot River near Bonner

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche occidentalis

3

2

3

.1 1.4

.2 .6

<.l 2.4

10.8 878

53.8 467

13.6 1,810

.7

.5

.8

434

85.5

497

.9

.3

1.5

136

223

124

12340500 Clark Fork above Missoula

Arctopsyche grandis

Hydropsyche cockerelli

Hydropsyche occidentalis

5

2

1

.7 1.5

1.0 3.2

1.1 2.8

24.4 907

45.9 2,050

49.8 2,010

3.2

5.6

7.1

687

1,090

2,030

.8

1.5

2.1

178

192

232

12353000 Clark Fork below Missoula 1

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

4

 2

2

2

1.2 1.6

1.1 .5

1.0 2.3

.9 1.8

27.3 991

47.8 119

37.7 1,600

31.8 1,240

2.5

<1.5

3.4

3.6

710

101

651

814

1.1

.2

1.3

1.2

166

263

156

155

'Samples collected about 30 miles downstream from water-quality station to conform to previous sampling location.

58 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 19. Recovery efficiency for trace-element analyses of standard reference material for biota 

[Abbreviations: ng/g, micrograms per gram of dry sample weight; SRM, standard reference material]

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of measurements

12

12

12

12

U

12

12

12

Certified concentration

(M8/g)

SRM sample TORT-2

26.7

.77

106

105

.35

13.6

2.5

180

Mean SRM recovery 

(percent)

95.0

146

93.4

92.6

106

89.9

80.1

94.2

95-percent ccifidence 

interval for SRM 

recovery 

(percent)

91.4-9?.6

138-154

90.3-9^.5

87.4-97.8

91.0-121

86.4-93.4

76.7-83.5

90.5-97.9

Eight samples were at or below the analytical detection limits.

TA 8LE 19 59
Table 20. Trace-element analyses of procedural blanks for biota

[Procedural blanks were not diluted prior to analysis. Abbreviation: |ig/mL, micrograms per milliliter. Symbol: <, less than]

Station 

number name ratio Cadmium

Trace-element concentration, in ng/mL

Chro- _ , Copper Iron mium

, . Manga- ... . , Lead 6 Nickel 

nese

Zinc

12323600

12323750

12323800

461415112450801

461559112443301

461903112440701

12324200

12324590

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

Silver Bow Creek at Opportunity 1:1 O.0 1

Silver Bow Creek at Warm Springs 1:1 <.0 1

Clark Fork near Galen 1 : 1 <.0 1

Clark Fork below Lost Creek, near Galen 1:1 <.0 1

Clark Fork near Racetrack 1 : 1 <.0 1

Clark Fork at Dempsey Creek diversion, 1:1 <.0 1 

near Racetrack

Clark Fork at Deer Lodge 1:1 < 0 1

Little Blackfoot River, near Garrison 1:1 <.0 1

Clark Fork at Goldcreek 1:1 <.01

Flint Creek near Drummond 1:1 <.0 1

Clark Fork near Drummond 1:1 <.0 1

Rock Creek near Clinton 1:1 <.0 1

Clark Fork at Turah Bridge, near Bonner 1:1 <.0 1

Blackfoot River near Bonner 1:1 <.0 1

Clark Fork above M issoula 1:1 <.0 1

Clark Fork below Missoula 1:1 <.0 1

O.OI O.03 0.31 O.I

<01 <.03 <10 <1

<01 <03 .30 <.l

<01 <03 .60 <1

<01 <03 .30 <.l

<.01 <.03 .80 <.l

<01 <.03 <10 <1

<01 <03 <.10 <.l

<01 <.03 <.10 <.l

<01 <03 .20 <1

<01 <03 .30 <.l

<.01 <.03 <.10 <.l

<01 <.03 <10 <1

<.01 <.03 <.10 <.l

<.01 <03 1.30 <1

<.01 <.03 <.10 <1

0.17 0.01

<01 <01

.05 <.01

.80 <.01

<01 <01

.16 <.01

.02 <.01

.09 <01

.08 <.01

.22 <.01

.14 <.01

<.01 <.01

<.01 <.01

<.01 <01

.03 <.01

.08 <.01

0.08

.07

<04

.05

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

60 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985

through September 1998

[Abbreviations: f^/s, cubic feet per second; °C, degrees Celsius; ug/L, micrograms per liter, uS/cm, microsiemens per centimeter at 25 °C; mg'L, milligrams

per liter, mm, millimeter, ton/d, tons per day. Symbols: <, less than minimum reporting level 1 ; --, indicates insufficient data

greater than minimum reporting level to compute statistic]

Property or constituent and reporting unit

Number of 

Maximum 

samples

Minimum Mean Median

12323230-BLACKTAIL CREEK AT HARRISON AVENUE. AT BUTTE. MONT.

Period of record for water-quality data

Streamflow, instantaneous (f^/s)

Specific conductance, onsite (jaS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ug/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ug/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

: March

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

1993-August 1995, December 1996-September 1998

156

412

17.0

8.2

140

39

11

18

13

<1

.5

52

10

4,200

480

47

1

240

100

130

11

139

59

%

3.1

116

2.0

7.3

38

11

2.7

2

1

<1

<.l

2

<1

260

24

<1

<.5

30

17

<10

<3

2

.04

50

19

251

8.1

7.8

100

28

6.9

7

5

--

-

9

24

895

203

24

2.3

66

41

2 13

25

20

2.4

83

9.3

248

7.5

7.8

100

29

6.8

6

4

<1

<.l

7

4

625

195

1

<.5

60

38

<10

<10

9

.2

86

TABLE 21 61
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit

12323250-SILVER BOW CREEK

Period of record for water-quality data:

Streamflow, instantaneous (fP/s)

Specific conductance, pnsite (^S/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3 )

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (jag/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (^ig/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (\\glL)

Manganese, total recoverable (^ig/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (jJg/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

Number of 

samples

BELOW BL

Maximum Minimum Mean

ACKTAIL

Median

CREEK. AT BUTTE. MONT.

March 1993-August 1995, December

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

44

43

43

43

134

691

17.0

7.8

180

52

13

45

13

6

6.2

550

300

7,400

270

250

2.4

1,600

1,700

2,200

2,200

405

70

94

15

226

1.5

7.2

66

19

4.5

8

4

1

.5

47

19

250

20

3

<.5

320

210

350

200

3

.14

42

1996-September 1998

35

453

9.9

7.5

143

41

10

17

7

3

2.2

186

81

1,600

116

30

2 .9

727

658

931

761

44

5.8

82

28

464

9.0

7.5

145

42

10

14

8

3

2.0

155

70

P70

110

12

.8

680

665

900

710

16

1.3

86

62 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams 

in the Upper Clark Fork Basin, Montana
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit

Number of 

samples

Maximum Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for water-quality data

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (|aS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (|ag/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (|ag/L)

Copper, total recoverable (|ag/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (|ag/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (|ag/L)

Manganese, dissolved (|ag/L)

Zinc, total recoverable (|ag/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

: March 1993-August 1995, December 1996-September 1998

46

45

45

45

45

45

45

45

45

45

45

45

45

45

45

45

45

45

45

45

45

46

46

46

361

593

18.0

8.9

200

55

15

240

34

49

41

3,900

450

24,000

310

650

5.1

10,000

9,300

15,000

13,000

801

781

95

26

202

0.0

7.2

60

18

3.4

11

1

1

.1

79

25

290

3

7

<.5

230

190

230

110

6

.42

37

94

366

8.8

8.2

130

39

8.3

34

10

3

2.2

322

70

2,200

62

54

2 .9

826

702

907

586

72

35

75

62

368

9.0

8.2

130

40

8.1

18

9

2

1.2

160

51

1,000

44

21

.6

600

500

540

310

25

4.2

79

TABLE 21 63
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit

12323750--SILVER

Number of 

samples Maximum Minimum Mean Median

BOW CREEK AT WARM SPRINGS. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (fP/s) 52

Specific conductance, onsite (uS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ug/L)

Arsenic, dissolved (ug/L)

Cadmium, total recoverable (Mg/L)

Cadmium, dissolved (ug/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (Mg/L) 

Iron, dissolved (Mg/L) 

Lead, total recoverable (ug/L)

Lead, dissolved (Mg/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (Mg/L) 

Zinc, total recoverable (Mg/L) 

Zinc, dissolved (Mg/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

50

51

50

50

50

50

50

50

50

50

50

50

50 

50 

50

50

50

50 

50 

50

52

52

51

March 1993-September 1998

662 24

614

22.0

9.3

260

78

19

94

60

<1

.3

80

40

3,000 

93 

15

1.0

600

530 

180

73

229

279

97

265

.5

8.0

110

34

5.9

12

8

<1

<.l

8

4

130 

<5

<.5

60

12 

<3

2

.26

43

185

434

11.0

8.8

181

53

12

27

22

-

2 .1

27

13

450

2 18 

23

-

201

127 

2 58 

2 13

16

13

81

148

431

12.0

8.8

175

52

12

24

20

<1

<.l

23

11

350 

15 

2

<.5

165

94 

45 

9

8

2.6

83

64 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams 

in the Upper Clark Fork Basin, Montana
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean

420

795

16.0

8.6

420

130

22

27

14

97

16

1,700

30

14

2.8

139

.5

7.4

72

22

3.8

3

3

40

3

124

304

8.5

8.2

149

46

8.6

9

5

26

4

422

11

2 3

Median

12323770-WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

Period of record for water quality data: March 1993-September 1998

Streamflow, instantaneous (ft3/s) 34

Specific conductance, onsite (jaS/cm) 33

Temperature, water (°C) 34

pH, onsite (standard units) 33

Hardness, total (mg/L as CaCO3 ) 33

Calcium, dissolved (mg/L) 33

Magnesium, dissolved (mg/L) 33

Arsenic, total recoverable (|ug/L) 33

Arsenic, dissolved (|ug/L) 33

Cadmium, total recoverable (|ug/L) 33

Cadmium, dissolved (ng/L) 33

Copper, total recoverable (pg/L) 33

Copper, dissolved (ng/L) 33

Iron, total recoverable (|ug/L) 33

Iron, dissolved (ng/L) 33

Lead, total recoverable (ng/L) 33

Lead, dissolved (|ig/L) 33

95

267

8.8

8.3

130

40

7.3

6

4

< 1 

11 

3

160 

9 

1

Manganese, total recoverable (|ug/L)

Manganese, dissolved (|Jg/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (pg/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

33

33

33

33

34

33

34

1,400

570

60

10

100

87

88

90

43

<10

<3

2

.09

55

278

161

2 15

2 3

26

15

75

200

110

10

<10

12

3.0

76

TABT ,E 21 65
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit

12323800-CL

Number of _ . .

, Maximum samples

,ARK FORK NEAR GALEN.

Period of record for water-quality data

Streamflow, instantaneous (fr'/s) 93

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (jig/L)

Arsenic, dissolved (jig/L) 

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (jig/L)

Copper, total recoverable (jig/L)

Copper, dissolved (fig/L)

Iron, total recoverable (jig/L)

Iron, dissolved (jig/L) 

Lead, total recoverable (ng/L) 

Lead, dissolved ((ig/L)

Manganese, total recoverable (jig/L)

Manganese, dissolved (jig/L)

Zinc, total recoverable (fig/L)

Zinc, dissolved (jig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

81

92

80

79

79

79

79

79 

79

79

78

79

79

79 

79 

79

79

79

79

79

93

93

92

Minimum

MONT.

: July 1988-September 1998

1,050 14

720

22.5

9.0

370

110

22

78

53 

3

1

240

50

9,200

110 

28 

3

1,400

380

360

110

338

459

97

220

.0

7.5

96

29

5.5

3

4

<.l

8

3

90

3

80

31

<10

<3

2

.12

41

Mean

233

429

9.5

8.4

188

56

12

21

15

2.3

2.1

40

12

675

18

25 

2.3

290

126

62

16

23

29

78

Median

145

435

9.2

8.5

190

57

12

16

12

<.l

26

9

350

12 

3

230

100

50

11

9

2.9

78

66 Water-quality, bed-sediment, aid biological data (October 1997 through September 1998) and statlstkal summaries of data for streams 

IB the Upper Clark Fork Basin, Montana
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit

12324200-CL

Number of 

samples Maximum Minimum Mean Medhn

,ARK FORK AT DEER LODGE. MONT.

Period of record for water-quality data

Streamflow, instantaneous (ftVs)

Specific conductance, onsite (uS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCC^)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ug/L)

Arsenic, dissolved (ug/L)

Cadmium, total recoverable (ug/L)

Cadmium, dissolved (ug/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L)

Lead, total recoverable (ug/L)

Lead, dissolved (Mg/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

145

128

144

93

85

85

85

95

95

95

95

94

95

95

95

95

95

95

95

95

95

145

145

136

: March 1985-September 1998

1,920

642

23.0

8.7

270

81

18

220

39

5

2

1,500

120

29,000

190

200

6

4,600

400

1,700

230

2,250

8,690

99

23

242

.0

7.4

100

32

5.9

8

7

<1

<-l

10

4

60

<3

<1

<.5

30

1

10

<10

2

.29

40

311

491

9.4

8.2

205

61

13

28

15

2.6

2.1

114

14

2,250

2 17

2 15

2.6

332

46

130

17

91

212

70

229

510

10.0

8.2

210

62

14

18

13

<1

<1

52

10

790

10

6

<.6

180

33

70

13

25

15

71

TABLF 21 67
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit Maximum Minimum Mean Median

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT. 

Period of record for water-quality data: March 1985-September 1998

Streamflow, instantaneous (ft^s) 78 2,080 21 313 186

Specific conductance, onsite (|aS/cm) 66 300 120 220 215

Temperature, water (°C) 77 22 .0 7.8 7.0

pH, onsite (standard units) 65 8.5 7.0 8.0 8.0

Hardness, total (mg/L as CaCO3) 60 140 51 101 99

Calcium, dissolved (mg/L) 60 43 14 29 28

Magnesium, dissolved (mg/L) 60 9.4 3.3 6.8 6.8

Arsenic, total recoverable (ng/L) 65 174 7 6

Arsenic, dissolved (ng/L) 65 735 5

Cadmium, total recoverable (|jg/L) 65 2 <1 2 .3 <1

Cadmium, dissolved (|jg/L) 65 1 <. 1 -- <1

Copper, total recoverable (|ag/L) 64 45 <1 2 5 3

Copper, dissolved (ng/L) 65 7 <1 2 2 2

Iron, total recoverable (ng/L) 65 25,000 20 1,400 310

Iron, dissolved ^g/L) 65 120 <3 2 37 27

Lead, total recoverable (ng/L) 65 25 <1 2 3 <5

Lead, dissolved (|Jg/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (|Jg/L)

Zinc, total recoverable (|Jg/L)

Zinc, dissolved (|Jg/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

64

65

65

65

65

78

78

78

6

1,100

30

140

24

1,410

7,920

97

<.5

<10

1

<10

<3

1

.08

49

2.5

2 82

8

2 16

2 4

59

171

74

<1

30

8

<10

<10

10

6.6

78

68 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams 

in the Upper Clark Fork Basin, Montana
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean

921

360

9.0

8.3

158

47

10

18

11

59

9

,300

222

2o

Median

12324680-CLARK FORK AT GOLDCREEK MONT. 

Period of record for water-quality data: March 1993-September 1998

Streamflow, instantaneous (ft3/s) 51 3,920 87

Specific conductance, onsite (}iS/cm) 50 496 207

Temperature, water (°C) 51 20.0 .0

pH, onsite (standard units) 50 8.7 7.9

Hardness, total (mg/L as CaCO3 ) 50 230 86

Calcium, dissolved (mg/L) 50 68 26

Magnesium, dissolved (mg/L) 50 15 5.1

Arsenic, total recoverable (^g/L) 50 75 8

Arsenic, dissolved (|ig/L) 50 20 6

Cadmium, total recoverable (|ag/L) 50 2 <1

Cadmium, dissolved (Mg/L) 50 .2 <. 1

Copper, total recoverable (Mg/L) 49 440 8

Copper, dissolved (Mg/L) 49 36 3

Iron, total recoverable (Mg/L) 50 12,000 60

Iron, dissolved (Mg/L) 50 100 <3

Lead, total recoverable (Mg/L) 49 73 <1

Lead, dissolved (Mg/L) 49 .8 <.5

661

372 

9.0 

8.3

IfO

10 

14 

10 

<1

<.l 

40

7

680 

15

5

Manganese, total recoverable (Mg/L)

Manganese, dissolved (Mg/L)

Zinc, total recoverable (Mg/L)

Zinc, dissolved (Mg/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

50

50

50

50

51

51

51

1,100

43

510

26

752

7,960

93

30

10

10

<3

2

.94

43

164

21

69

2 9

76

397

74

125

21

50

7

2 9

47

T

TABLE 21 69
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1 998 (Continued)

Property or constituent and reporting unit Maximum Minimum Mean

205

291

8.6

8.3

137

37

11

19

9

2.2

8

22

1,050

43

2 13 

2o

Median

12331500-FLIINT CREEK NEAR DRUMMOND. MONT. 

Period of record for water-quality data: March 1985-September 1998

Streamflow, instantaneous (fl^/s) 100 892 4.2

Specific conductance, onsite (jaS/cm) 89 507 134

Temperature, water (°C) 98 21.0 .0

pH, onsite (standard units) 86 8.8 7.5

Hardness, total (mg/L as CaCO3 ) 79 260 59

Calcium, dissolved (mg/L) 79 73 16

Magnesium, dissolved (mg/L) 79 20 4.3

Arsenic, total recoverable (ng/L) 86 57 7

Arsenic, dissolved (|ag/L) 86 20 5

Cadmium, total recoverable (jag/L) 86 3 <1

Cadmium, dissolved (jag/L) 86 .1 <.l

Copper, total recoverable (|ag/L) 85 32 1

Copper, dissolved (jag/L) 86 7 <1

Iron, total recoverable (jag/L) 86 7,200 70

Iron, dissolved (jag/L) 86 240 3

Lead, total recoverable (jag/L) 86 87 <1

Lead, dissolved (|ag/L) 86 7 <.5

130

293

9.0

8.3

140

37

11

15

8

6

2

580

28

9

Manganese, total recoverable (|ag/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (|ag/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

86

86

86

86

100

100

100

1,600

120

290

27

556

904

98

50

14

<10

<3

3

.03

28

234

40

245

26

57

53

80

155

34

30

4

31

9.6

84

70 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams 

in the Upper Clark Fork Basin, Montana
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum

12331800--CLARK FORK NEAR DRUMMOND.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCC^)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (|Jg/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (|Jg/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

51

50

51

50

50

50

50

50

50

50

50

48

48

50

50

46

46

50

50

50

50

51

51

51

MONT.

Mean Median

March 1993-September 1998

3,860

630

21.0

8.5

300

83

22

62

20

2

.2

360

24

8,800

150

56

1.2

880

50

490

21

530

4,720

91

149

189

.5

7.8

74

21

5.2

8

7

<1

<.l

5

1

50

<3

<1

<.5

20

8

<10

<3

2

1.9

38

1,290

385

10.0

8.3

173

50

12

19

11

--

--

60

8

1,430

225

2 11

2 .3

191

19

2 90

2 8

89

516

73

942

401

10.0

8.2

180

52

12

16

10

<1

<.l

33

6

775

11

6

<.5

130

16

50

6

^0

1C3

73

TABLE 21 71
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

1233451G-ROCK CREEK NEAR CLINTON. MONT.

Period of record for water-quality data

Streamflow, instantaneous (frVs)

Specific conductance, onsite (fiS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCC^)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (fig/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (jAg/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (fig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

77

68

77

67

59

59

59

65

65

65

65

63

64

65

65

63

63

65

65

65

65

77

77

77

: March 1985-September 1998

5,060

155

18

8.6

90

23

8.0

3

1

3

1

41

6

2,100

160

19

5

90

8

60

15

223

3,050

95

113

55

.0

6.9

22

5.9

1.9

<1

<1

<1

<.l

<1

<1

20

5

<1

<.5

<10

<1

<10

<3

1

.31

35

1,040

104

7.9

7.9

49

13

4.2

2 .9

2 1

2.4

~

2 5

2 1

357

38

22

2.6

2 18

22

29

22

23

162

69

558

S4

8.0

7.9

^9

13

4.0

<-l

<\

<\

<\

2

<1

180

35

<5

<1

10

2

<10

<3

6

14

70

72 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams 

in the Upper Clark Fork Basin, Montana
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum

12334550-CLARK FORK AT TURAH BRIDGE. NEAR

Period of record for water-quality data

Stream flow, instantaneous (fi^/s)

Specific conductance, onsite (|^S/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable ([ig/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (|ag/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

148

123

147

94

84

84

84

93

93

93

93

91

92

93

93

89

89

93

93

93

93

148

148

137

Minimum Mean Median

BONNER. MONT.

: March 1985-September 1998

9,560

483

22.0

8.7

210

59

14

110

17

4

1

500

25

19,000

190

100

7

2,000

37

1,100

39

1,370

34,700

98

296

140

.0

7.4

58

17

3.9

5

4

<1

<.l

3

2

60

<3

<1

<.5

10

1

<10

<3

2

3.5

27

1,930

309

9.1

8.2

135

38

9.5

12

6

2 .4

--

49

6

1,460

2 28

2 11

2 .5

168

9

2 85

2 8

68

797

72

1,160

329

9.5

8.2

140

39

9.5

8

6

<1

<.l

23

5

550

16

5

<1

90

7

40

7

23

66

72

TABLE 2" 73
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12340000--BLACKFOOT RIVER NEAR BONNER. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (jaS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCC^)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (jag/L)

Cadmium, total recoverable (jag/L)

Cadmium, dissolved (|Jg/L)

Copper, total recoverable (jag/L)

Copper, dissolved (jag/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ug/L)

Manganese, total recoverable (jag/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (jag/L)

Zinc, dissolved (|ag/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

108

85

108

68

61

61

61

68

68

68

68

65

66

68

68

64

64

68

68

68

68

108

108

106

March 1985-September 1998

13,400

294

20.5

8.7

140

37

13

4

2

2

1

34

7

3,600

100

25

8

180

11

60

15

271

7,670

98

344

130

.0

7.5

55

14

4.9

<1

<1

<1

<.l

<1

<1

20

<3

<1

<.5

<10

<1

<10

<3

1

1.1

42

2,740

205

8.9

8.2

101

26

8.9

2 1

2 .9

2 .4

~

28

22

582

220

2 5

2 1

238

23

2 10

24

33

607

79

1,280

203

9.0

8.3

95

24

8.4

1

<1

<1

<1

6

1

240

13

2

<1

20

2

<10

<3

9

30

81

74 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams 

in the Upper Clark Fork Basin, Montana
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1998 (Continued)

Property or constituent and reporting unit , Maximum Minimum Mean Median K samples

12340500-CLARK FORK ABOVE M1SSOULA. MONT. 

Period of record for water-quality data: July 1986-September 1998

Streamflow, instantaneous (ft3/s) 114 21,600 720 4,580 2,360

Specific conductance, onsite (jaS/cm) 91 399 145 256 261

Temperature, water (°C) 111 19.5 .0 9.0 8.5

pH, onsite (standard units) 71 8.6 7.9 8.3 8.3

Hardness, total (mg/L as CaCO3 ) 71 170 61 118 120

Calcium, dissolved (mg/L) 71 46 14 32 32

Magnesium, dissolved (mg/L) 71 13 5.3 9.2 9.2

Arsenic, total recoverable ((ag/L) 71 69 2 6 4

Arsenic, dissolved ((ag/L) 71 913 3

Cadmium, total recoverable (ng/L) 71 5 <l <1

Cadmium, dissolved (ng/L) 71 .1 <.l - ^.1

Copper, total recoverable (ng/L) 69 400 2 20 8

Copper, dissolved (^g/L) 70 11 1 3 2

Iron, total recoverable (ng/L) 71 13,000 60 753 270

Iron, dissolved (ng/L) 71 200 <3 2 25 16

Lead, total recoverable (|ag/L) 66 78 <1 24 2

Lead, dissolved (ng/L) 66 1 <.5 2 .6 <".5

Manganese, total recoverable ((ag/L) 71 1,100 10 76 50

Manganese, dissolved ((ag/L) 71 230 7 19 15

Zinc, total recoverable (ng/L) 71 1,100 <10 2 39 20

Zinc, dissolved (ng/L) 71 16 <3 2 5 3

Sediment, suspended concentration (mg/L) 114 824 2 41 10

Sediment, suspended discharge (ton/d) 114 21,900 6.1 1,130 62

Sediment, suspended (percent finer than 0.062 mm) 109 99 44 86 90

Multiple less-than (<) values for an individual constituent are the result of changes in analytical minimum reporting levels during the period of record. 

"Value is estimated by using a log-probability regression to predict the values of data less than the minimum reporting level (Helsel and Cohn, 1988).

TABLE 21 75
Table 22. Statistical summary of fine-grained bed-sediment data for the upper Clark Fork basin, Montana, 

August 1986 through August 1998

[Fine-grained bed sediment is material less than 0.064 millimeter in diameter. Concentrations are in micrograms per gram dry 

weight. Symbols: <, less than minimum reporting level; , indicates either too few samples (less than three) or insufficient data grea^r 

than the minimum reporting level to compute statistic. Number of samples represents the number of years that the constituent 

was analyzed, with each year represented by a single mean concentration of composite samples]

~ ^ , Number of Constituent ,

samples

Maximum

Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for fine-grained bed-sediment data: 1992-98

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

7

6

7

7

7

7

6

7

7

42.0

32.4

6,280

41,200

1,030

3,940

21.4

19.6

10,800

23.7 31.8

23.2 28.1

4,220 4,870

34,400 39,000

752 848

1,680 2,590

14.5 16.8

13.7 16.3

6,850 8,270

29.3

28.9

4,670

39,700

833

2,460

16.2

16.4

8,010

12323750-S1LVER BOW CREEK AT WARM SPRINGS. MONT.

Period of record for fine-grained bed-sediment data: 1992-98

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

7

6

7

7

7

7

6

7

7

12.2

34.1

769

27,200

100

17,700

19.1

2.1

2,220

5.3 7.9

12.8 22.6

259 464

19,500 22,400

58 78

1,470 6,960

12.5 15.5

.3 l l.3

620 1,230

6.7

23.6

358

20,800

74

7,230

15.2

'1.3

845

12323770-WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

Period of record for fine-grained bed-sediment data: 1995, 1997

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

2

2

2

2

2

2

2

2

2

3.9

33.4

892

22,400

86

8,790

21.9

3.7

421

2.6 3.2

30.8 32.1

848 870

21,900 22,100

85 86

2,020 5,400

17.6 19.8

3.2 3.4

372 396

--

~

-

~

--

76 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 22. Statistical summary of fine-grained bed-sediment data for the upper Clark Fork basin, Montana, 

August 1986 through August 1998 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

^ ... . Number of Maxi- .... .. Constituent , Minimum Mean samples mum

12323800-CLARK FORK NEAR GALEN. MONT.

Period of record for fine-grained bed-sediment data: 1987, 1991-98

9 20.1 6.4 11.1

6 33.9 22.1 28.5

9 2,300 1,090 1,390

9 39,800 22,600 29,900

9 235 116 154

9 15,600 2,780 8,690

6 23.2 17.7 20.0

9 5.5 <3.2 '3.8

9 3,560 1,160 2,000

4614151 1245080 1-CLARK FORK BELOW LOST CREEK. NEAR GALEN. MONT

Period of record for fine-grained bed-sediment data: 1996-98

3 9.0 6.8 8.1

3 34.5 32.0 33.1

3 2,050 1,360 1,710

3 32,700 30,800 31,600

3 197 168 185

3 5,900 3,540 4,470

3 19.9 17.8 18.8

3 7.0 4.2 6.0

3 1,680 1,284 1,470

461559112443301-CLARK FORK NEAR RACETRACK. MONT.

Period of record for fine-grained bed-sediment data: 1996-98

3 8.5 5.5 7.2

3 33.3 30.0 31.1

3 1,610 946 1,310

3 31,700 29,000 30,200

3 155 134 148

3 3,127 2,390 2,730

3 18.4 16.5 17.2

3 6.1 <3.3 U.6

3 1,550 1,030 1,250

Median

10.5

30.4

1,230

28,500

145

8,540

19.5

'3.7

1,820

8.4

32.9

1,730

31,400

190

3,980

18.7

6.8

1,460

7.5

30.1

1,370

29,800

153

2,680

16.7

6.0

1,190

461903112440701-CLARK FORK AT DEMPSEY CREEK DIVERSION. NEAR RACETRACK. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Period of record for fine-grained bed-sediment data: 1996-98

3 8.1 4.8 6.6

3 34.1 28.9 31.4

3 1,550 842 1,230

3 33,700 28,200 30,700

3 152 115 140

3 3,910 2,630 3,070

3 16.9 15.8 16.5

3 6.2 3.5 5.3

3 1,570 900 1,240

6.9

31.1

1,280

30,200

152

2,680

16.8

6.2

1,260

TAP^E 22 77
Table 22. Statistical summary of fine-grained bed-sediment data for the upper Clark Fork basin, Montana, 

August 1986 through August 1998 (Continued)

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc 

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc 

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc

 ... , Number of Maxi- ... . .. Constituent , Minimum Mean samples mum

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1990-98

11 9.0 5.1 7.0

6 43.9 19.5 33.2

11 4,180 837 1,550 

11 35,300 22,600 28,600 

11 242 121 162

11 6,020 1,460 2,630 

6 21.1 15.0 17.5

11 7.9 2.4 4.7

11 1,730 977 1,340 

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1994, 1998

4 1.5 .2 .8

2 52.9 22.1 37.5

4 85 38 60 

4 30,700 16,100 24,200 

4 53 36 41

4 2,700 905 1,390 

2 21.9 13.6 17.8 

4 .9 <.5 '.6

4 204 161 179 

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for fine-grained bed-sediment data: 1992-98

7 6.2 4.9 5.6

6 48.9 31.6 36.9

7 1,080 653 840 

7 30,600 20,500 25,600 

7 152 88 114

7 2,610 1,180 1,980 

6 18.6 15.0 17.0

7 4.8 2.3 3.6

7 1,320 1,070 1,170

12331500--FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for fine-grained bed-sediment data: 1986, 1989, 1992-98

9 4.5 <1.0 '2.6

6 29.2 21.1 25.4

9 73 55 62 

9 28,100 21,100 24,200 

9 240 151 182

9 5,510 2,370 3,710 

6 14.9 11.7 13.1

8 7.8 5.0 6.3

9 777 577 668

Median

7.4

35.6

1,210 

29,400 

159

2,320 

17.2

4.6

1,390 

.8

59 

25,100 

38

974 

'.6

175 

5.8

35.7

791 

26,400 

118

1,840 

17.1

3.7

1,160

2.4

25.2

63 

23,600 

179

3,560 

13.0

6.5

672

78 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 22. Statistical summary of fine-grained bed-sediment data for the upper Clark Fork basin, Montana, 

August 1986 through August 1998 (Continued)

^ A .A A Number of Maxi- ... . . _ Constituent . Minimum Mean samples mum

Median

12331800--CLARK FORK NEAR DRUMMOND. MONT.

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese

Nickel 

Silver

Zinc

Period of record for fine-grained bed-sediment data: 1986-87, 1991-98

10 5.4 3.0 4.5

6

10 

10 

10

10 

6 

10

10

35.4 17.0 30.5

747 469 567 

27,000 16,500 22,800 

135 83 102

2,780 1,220 1,860 

16.8 14.0 15.7 

4.7 <3.2 '3.0

1,230 939 1,090

4.6

33.3

565 

23,800 

101

1,890 

15.8 

'3.0

1,110

12334510-ROCK CREEK NEAR CLINTON. MONT.

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Period of record for fine-grained bed-sediment data: 1986-87, 89, 1991-98

11 <.7 <.3 '.4 ! <1.0

6

11 

11 

11

11 

6 

10

11

27.9 16.5 22.9

15 3 12 

21,400 13,100 18,000 

16 <3 ! 7

724 126 398 

13.7 10.8 12.5 

.8 <.3 U

58 36 48

23.8

14 

18,000

'7

382 

12.9 

k5

48

12334550-CLARK FORK AT TURAH BRIDGE. NEAR BONNER. MONT.

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc 

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Period of record for fine-grained bed-sediment data: 1986, 1991-98

9 5.2 3.1 3.8

6

9 

9 

9

9 

6

9

34.7 15.3 26.2

635 300 414 

24,000 15,100 19,900 

115 49 78

2,270 671 1,280 

16.3 11.6 14.7

3.9 1.3 2.3

9 1,160 775 925 

12340000-BLACKFOOT RIVER NEAR BONNER. MONT.

3.6

28.5

356 

21,700

74

1,260 

16.0

2.4

909

Period of record for fine-grained bed-sediment data: 1986-87, 1991, 1993-96, 1998

8 <1.5 <3 U '<1.0

5

8 

8 

8

8 

5 

8

8

25.8 15.1 20.6

25 16 21 

20,200 12,400 16,700 

20 <13 ! 12

672 298 494 

13.4 11.7 12.7 

.7 <.3 '.4

73 54 63

22.0

21 

16,900 

11

492 

12.7 

k5

62

TABLE 22 79
Table 22. Statistical summary of fine-grained bed-sediment data for the upper Clark Fork basin, Montana, 

August 1986 through August 1998 (Continued)

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc

^ ^^ Number of Maxi- ... . .. Constituent , Minimum Mean samples mum

12340500-CLARK FORK ABOVE MISSOULA. MONT.

Period of record for fine-grained bed-sediment data: 1997-98

2 3.7 2.3 3.0

2 30.6 28.5 29.6

2 516 282 399 

2 24,300 21,800 23,000 

2 63 60 61

2 1,290 1,160 1,220 

2 15.0 14.5 14.8

2 2.9 <3.2 2.2

2 924 6% 810

12353000-CLARK FORK BELOW MISSOULA. MONT.2

Period of record for fine-grained bed-sediment data: 1986, 1990-98

10 2.6 1.1 1.7

6 27.6 18.8 23.1

10 293 98 165 

10 21,100 14,500 18,800 

10 58 12 38

10 2,530 752 1,480 

6 14.1 11.8 13.1

10 2.1 .4 1.3

10 675 319 434

Median

~

-

-

1.8

22.7

147 

19,500 

36

1,310 

13.3

1.3

436

'Value determined by arbitrarily substituting one-half of the detection level for censored (<) values, when both 

uncensored and censored values are used in determining the mean. When all data are below the detection level, the 

median is determined by ranking the censored values in order of detection level. No mean is reported when all values 

are below the detection level.

f\

Samples collected about 30 miles downstream from water-quality station to conform to previous sampling location.

80 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, 

August 1993 through August 1998

[Bulk bed sediment is material smaller than about 10 mm in diameter. Concentrations are in micrograms per gram dry weight.

Symbols: <, less than minimum reporting level; , indicates either too few samples (less than three) or insufficient data greater than the minimum

reporting level to compute statistic. Number of samples represents the number of years that the constituent was analyzed, with

each year represented by a single mean concentration of composite samples]

^ ^ A Number of Constituent samples

Maximum

Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY. MONT.

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc 

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Period of record for bulk bed-sediment data: 1993-95, 1997-98

5 12.7 4.9 7.6

5

5 

5 

5

5 

5

5

16.2

1,550 

29,300 

300

1,670 

8.9

4.8

9.6 13.0

670 961 

18,600 23,100 

221 252

504 867 

6.0 6.7

3.4 3.9

5 3,420 1,720 2,240 

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.

Period of record for bulk bed-sediment data: 1993, 1995-98

5 1.7 <1.5 'l.O

5

5 

5 

5

5 

5 

5

5

11.8

111 

12,300 

33

884 

9.2 

1.3

303

9.2 10.5

20 65 

7,200 10,200 

<10 '16

209 638 

4.8 6.6 

<.3 '.7

93 186

6.7

12.7

831 

20,800 

248

740 

6.0

3.9

2,050 

'1.2

10.1

66 

11,000 

11

722 

5.5 

'1.6

157

12327700-WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc

Period of record for bulk bed-sediment data: 1995, 1997

2 1.0 <.8 '.7

2

2 

2 

2

2 

2

2

2

11.8

205 

10,900 

34

2,650 

7.8

1.1

148

9.7 10.8

203 204 

8,980 9,960 

18 26

1,220 1,930 

5.7 6.8

.9 1.0

146 147

-

TABLE 23 81
Table 23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, 

August 1993 through August 1998 (Continued)

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

_, i<A A Number of Maxi- .... .. Constituent , Minimum Mean samples mum

12323800-CLARK FORK NEAR GALEN. MONT.

Period of record for bulk bed-sediment data: 1993-98

6 6.0 1.5 3.5

6 23.0 4.2 13.4

6 685 223 404 

6 31,300 9,930 20,400 

6 158 41 80

6 5,410 900 2,020 

6 12.5 4.9 7.9 

6 1.9 .7 '1.4

6 1,280 417 704 

461415112450801-CLARK FORK BELOW LOST CREEK. NEAR GALEN. MONT

Period of record for bulk bed-sediment data: 1996-98

3 3.1 1.9 2.5

3 17.5 12.0 14.2

3 763 398 539 

3 21,000 16,000 18,100 

3 104 72 85

3 1,740 1,260 1,460 

3 8.2 6.7 7.6 

3 2.8 <3.4 '2.2

3 787 522 647

4615591 12443301-CLARK FORK NEAR RACETRACK. MONT.

Period of record for bulk bed-sediment data: 1996-98

3 3.4 1.9 2.4

3 16.4 12.4 13.8

3 594 361 443 

3 18,200 16,200 17,400 

3 87 66 77

3 1,680 760 1,310 

3 9.9 5.5 7.6 

3 2.6 <3.2 '2.0

3 743 472 583

Median

3.3

13.1

362 

21,000

72

1,410 

7.3 

'1.6

665

2.5

13.1

455 

17,300 

78

1,390 

7.7 

»2.1

632

2.1

12.7

375 

1 7,900 

78

1,500 

7.3 

'1.9

535

461903112440701-CLARK FORK AT DEMPSEY CREEK DIVERSION. NEAR RACETRACK. MONT.

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Period of record for bulk bed-sediment data: 1996-98

3 3.9 1.8 2.9

3 20.9 16.3 18.2

3 651 424 551 

3 25,400 20,100 22,100 

3 89 58 78

3 1,940 825 1,540 

3 12.8 5.5 9.4 

3 2.8 <3.2 1 2.\

3 804 448 619

3.0

17.3

577 

20,900 

88

1,860 

10.0 

2.0

604

82 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, 

August 1993 through August 1998 (Continued)

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc 

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc

 ... . Number of Maxi- _.. . _. Constituent . Minimum Mean samples mum

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for bulk bed-sediment data: 1993-98

6 3.1 2.0 2.4

6 24.5 12.1 17.7

6 691 281 436 

6 25,000 13,200 19,100 

6 85 45 73

6 2,060 653 1,160 

6 12.3 7.7 9.8 

6 2.8 <.7 '1.6

6 777 456 581 

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

Period of record for bulk bed-sediment data: 1994, 1998

2 .7 <1.2 '.6

2 33.2 14.7 23.9

2 20 19 20 

2 21,000 15,600 18,300 

2 18 12 15

2 420 308 364 

2 15.2 8.6 11.9

2 <1.6 <.7 '-

2 86 73 79

12324680--CLARK FORK AT GOLDCREEK. MONT.

Period of record for bulk bed-sediment data: 1993-98

6 5.2 2.0 3.3

6 33.2 17.6 24.2

6 858 243 495 

6 24,900 15,500 20,000 

6 86 46 68

6 2,600 649 1,340 

6 15.9 9.1 12.5 

6 3.7 <.7 '2.0

6 1,020 549 749

12331500--FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-98

6 3.2 .3 1.4

6 13.9 4.9 10.3

6 40 19 28 

6 15,700 8,630 13,400 

6 120 51 85

6 3,200 1,150 2,300 

6 8.0 5.3 6.3

6 5.8 3.3 4.5

6 429 190 316

Median

2.2

17.9

412 

19,000 

78

1,040 

10.1 

'1.5

564

--

~

~

~

2.9

22.3

421 

19,100

72

1,230 

12.2 

'1.6

686

1.2

10.9

28 

13,900 

82

2,350 

5.9

4.5

328

TABLE 23 83
Table 23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, 

August 1993 through August 1998 (Continued)

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc

 ... . Number of Maxi- _ _. . _ _ Constituent , Minimum Mean samples mum

12331800-CLARK FORK NEAR DRUMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-98

6 3.9 <1.6 [ 2.2

6 29.5 13.8 21.7

6 605 173 329 

6 21,800 14,100 17,600 

6 78 35 54

6 1,510 711 1,140 

6 14.2 9.0 11.5 

6 3.5 .5 h.9

6 939 434 653 

12334510-ROCK CREEK NEAR CLINTON. MONT.

Period of record for bulk bed-sediment data: 1993-98

6 <1.5 <.8 l6 

6745 

14.3 6.6 9.6

6 11,100 6,380 8,500 

6 <13 <9.6 '5

6 265 91 190 

6 8.2 4.5 5.8 

6 <1.6 .1 U

6 29 16 20

12334550-CLARK FORK AT TURAH BRIDGE. NEAR BONNER. MONT.

Period of record for bulk bed-sediment data: 1993-98

6 2.9 .5 h.6

6 23.8 6.9 15.9

6 336 75 207 

6 19,100 9,530 14,100 

6 67 21 40

6 1,470 234 711 

6 14.0 6.4 9.8 

6 2.9 <.3 l l.2

6 769 281 509 

12340000-BLACKFOOT RIVER NEAR BONNER. MONT.

Period of record for bulk bed-sediment data: 1993-94

2 <1.2 <.8 1 --

2 17.7 6.7 12.2

2 19 14 16 

2 16,600 10,300 13,400 

2 10 8 9

2 305 179 242 

2 9.8 7.6 8.7

2 <7 <.5 l2 58 33 46

Median

'1.8

21.6

256 

16,500 

53

1,180 

10.7 

M.6

568

^1.0

8.9

5 

8,180 

'5

190 

5.4 

'.3

19

'1.7

16.0

215 

13,700 

36

451 

9.8 

'.9

509

--

~

84 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for st-earns in the 

Upper Clark Fork Basin, Montana
Table 23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, 

August 1993 through August 1998 (Continued)

Constituent

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese

Nickel 

Silver

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Number of Maxi- ... . Minimum samples mum

12340500-CLARK FORK ABOVE MISSOULA. MONT.

Period of record for bulk bed-sediment data: 1997-98

2 <1.6 <.8

2 18.2 9.7

2 129 43 

2 16,000 11,500 13 

2 30 7

2 553 228 

2 10.3 8.2 

2 <3.3 .6

2 387 145

12353000-CLARK FORK BELOW MISSOULA. MONT.2

Period of record for bulk bed-sediment data: 1993-98

6 12.6 4.4

Mean

'--

14.0

86 

,700 

18

390 

9.3

h.i

266

'.5

7.5

6 77 22 44 

6 11,300 5,830 8,200 

6 19 <10 *9

6 444 223

6 7.1 3.5

6 172 83

362

5.3 

'.5

121

Median

~

-

~

,

6.9

39 

7,900

1 7

374 

5.2 

U

111

Value determined by arbitrarily substituting one-half of the detection level for censored (<) values, when both 

uncensored and censored values are used in determining the mean and/or median. When all data are below the detection 

level, the median is determined by ranking the censored values in order of detection level. No mean is reported when all 

values are below the detection level.

Samples collected about 30 miles downstream from water-quality station to conform to previous sampling location.

TAB'-E 23 85
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998

[Concentrations are in micrograms per gram dry weight. Symbols: <, less than minimum reporting level; , indicates either

too few samples (less than three) or insufficient data greater than the minimum reporting level to compute statistic, or element not analyzed.

Number of composite samples represents the total of all individual composite samples collected for every year that the constituent

was analyzed. Values for single samples are arbitrarily listed in the "Mean" column. Because Hydropsyche insects were not sorted to

the species level during 1986-89, statistics for stations sampled during those years are based on the results of all Hydropsyche species

combined. At some sites, statistics for the Hydropsyche morosa group are based on the combined results for two or more species]

Number of

Constituent composite 

samples

Maximum Minimum

12323600-SILVER BOW CREEK AT OPPORTUNITY.

Period of record for biological data: 1992,

Mean

MONT.

Mediar

1994-95, 1997-98

Brachycentrus spp.

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

2

2

2 

2

2

2 

2

2

12.5

1.1

592 

363

7.9

357 

1.0

888

11.6

.7

587 

335

7.4

231 

<1.0

686

12.0

.9

590 

349

7.6

294

.8

787

~

~

~

~

--

Hydropsyche cockerelli

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

5

5

5 

5

5

5 

5

5

6.3

8.0

462 

1,180

21.7

718 

2.1

898

4.1

1.0

269 

689

19.0

180

.7

749

4.9

3.7

365 

931

20.3

460 

1.4

818

4.7

3.1

333 

953

20.1

434 

1.6

805

Hydropsyche tana

Cadmium

Chromium

Copper 

Iron

Lead

Manganese

Nickel

Zinc

6

6

6 

6

6

6 

6

9.2

11.5

456 

1,520

21.0

969

1.8

4.8

.9

10.5

857

15.6

307 

.7

6 1,070 760 

12323750-SILVER BOW CREEK AT WARM SPRINGS.

Period of record for biological data : 1992-98

6.8

4.5

236 

1,100

18.6

634 

1.4

961 

MONT.

6.9

1.8

298 

1,050

18.3

675 

1.6

1,020

Hydropsyche cockerelli

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

20

20

20 

20 

20

20 

20

20

2.1

1.3

96.9 

1,240

5.7

2,450 

1.8

276

.2

.5

25.1 

351

.3

491

.3

118

.8

.8

46.5 

703 

3.3

997

.8

187

.6

.8

42.6

733 

3.0

829 

.8

182

86 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Number of .

Constituent composite Minimum . mum samples

Mean Median

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.-Continued

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1992-98

Hydropsyche occidentalis

4 1.1 .4

4 .17 .3

4 46.5 22.8

4 1,040 372

4 <3.6 <2.3

4 2,250 1,200

4 1.8 .7

4 202 149

Hydropsvche spp.

4 2.3 .4

4 1.4 .5

4 47.6 34.9

4 773 561

4 5.1 1.9

4 1,100 443

4 1.9 <4

4 285 141

1.3

1.2

33.9

649

'1.6

1,030

1.3

154

1.1

.8

40.9

680

2.9

725

'.8

195

.9

.8

39.4

741

h.7

1,960

1.2

176

.9

1.2

40.6

693

4.7

678

! .5

177

12323770- WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1995, 1997

Arctopsvche grandis

2 2.4 2.1

2 1.9 1.4

2 98.8 95.6

2 1,040 684

2 5.6 <6.3

2 2,280 1,340

2 2.3 1.8

2 222 197

Hydropsyche spp.

1

1

1

1

1

1

1

1

2.2

1.6

97.2

862

'4.4

1,810

2.0

210

<9.3

1.6

94.8

1,150

<16.7

956

2.0

129

~

--

--

--

--

-

--

--

--

TABLE 24 87
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Constituent

Number of 

composite 

samples

Maxi- ... . Minimum mum

Mean Median

12323800--CLARK FORK NEAR GALEN. MONT.

Period of record for biological data: 1987, 1991-98

Hydropsyche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

13

13

13

13

13

13

13

13

2.7 1.3

3.3 .8

181 49.8

1,510 902

11.0 1.2

2,950 1 ,070

3.1 1.0

299 136

1.7

1.6

96.3

1,200

7.0

1,960

1.6

214

1.7

1.4

97.5

1,160

7.7

1,850

1.3

216

Hydropsyche morosa group

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

5

5

5

5

5

5

5

5

3.2 2.4

4.6 1.8

185 156

1,890 1,360

12.4 7.1

3,960 2,360

3.6 1.9

349 292

2.5

2.6

173

1,510

8.5

3,500

2.3

309

2.4

2.2

175

1,430

7.9

3,860

2.1

303

Hvdropsvche occidentals

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

24

24

24

24

24

24

24

24

1.7 .7

6.6 .7

106 49.2

1,920 642

13.5 1.6

4,070 1,220

3.5 .8

278 170

1.1

1.8

79.2

1,190

6.6

2,400

1.6

200

1.1

1.5

78.2

1,170

6.3

2,290

1.6

197

Hvdropsvche tana

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

--

..

.-

--

..

--

1.5

1.4

92.9

1,340

9.0

2,160

2.1

206

--

~

--

--

--

--

--

-

Hydropsyche spp.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

4

0

4

4

4

0

0

4

3.5 2.6

154 135

1,540 1,190

13.5 10.5

--

..

329 279

3.0

148

1,400

12.2

-

--

308

3.0

-

152

1,450

12.4

--

--

313

88 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Number of M .

Constituent composite Minimum 

, mum

samples

Mean Media4614151 12450801-CLARK FORK BELOW LOST CREEK. NEAR GALEN. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-98

Hvdropsvche cockerelli

4 2.8 2.2

4 2.5 1.8

4 147 121

4 1,900 1,560

4 14.8 12.1

4 1,850 1,250

4 1.9 1.1

4 250 221

Hvdropsvche occidentalis

10 1.8 .9

10 3.3 1.3

10 157 52.1

10 1,920 963

10 12.4 6.6

10 2,300 1,270

10 1.7 .9

10 252 174

Hvdropsvche spp.

3 1.8 1.2

3 2.4 1.5

3 122 67.8

3 1,410 1,200

3 20.5 7.2

3 1,980 799

3 2.8 1.4

3 225 179

2.4

2.1

138

1,760

13.1

1,590

1.6

234

1.4

2.0

105

1,410

9.6

1,890

1.3

220

1.5

1.9

104

1,320

12.5

1,580

1.9

197

2.4

2.0

142

1,780

12.7

1,630

1.6

233

1.5

1.8

121

1,430

10.1

2,090

1.4

233

1.4

1.7

121

1,340

9.7

1,950

1.4

186

4615591 12443301 -CLARK FORK NEAR RACETRACK. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-97

Hvdropsvche cockerelli

5 1.9 1.1

5 2.7 .7

5 109 50.5

5 1,370 862

5 10.5 6.1

5 1,530 646

5 1.4 1.0

5 199 139

1.5

1.7

84.0

1,100

8.3

971

1.2

176

1.6

1.4

91.4

1,080

8.7

878

1.3

179

TABLE 24 89
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Number of . .

IVI fl\i Constituent composite Minimum . mum \ samples

Mean Median

4615591 12443301-CLARK FORK NEAR RACETRACK. MONT. -Continued

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-98

Hvdropsyche occidentalis

9 2.2 .7

9 2.6 1.5

9 160 64.4

9 1,880 1,300

9 11.7 9.7

9 2,640 1,090

9 1.7 1.1

9 255 203

Hvdropsyche spp.

._

_.

-

..

..

-

1.5

2.1

111

1,540

10.2

1,760

1.3

233

1.0

.7

82.9

1,140

5.7

910

1.1

151

1.5

2.0

107

1,520

10.1

2,020

1.2

230

~

-

~

~

--

4619031 12440701-CLARK FORK AT DEMPSEY CREEK DIVERSION. NEAR RACETRACK. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-98

Arctopsyche grandis

..

..

..

..

..

..

-

Hvdropsvche cockerelli

2 1.6 .9

2 1.3 1.0

2 143 87.6

2 1,290 831

2 8.4 6.8

2 697 487

2 1.9 1.6

2 180 162

1.7

<2.4

30.8

340

<14.5

510

1.0

87

1.2

1.2

115

1,060

7.6

592

1.8

171

~

--

-

~

~

90 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streans in the 

Upper Clark Fork Basin, Montana
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Constituent

Number of , . Maxi- . composite Minimum mum samples

Mean Mediae

461903112440701-CLARK FORK AT DEMPSEY CREEK DIVERSION. NEAR RACETRACK. MONT.-Continuei»

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium 

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Period of record for biological data: 1996-98

Hydropsvche occidentalis

1 1.7 .7

7 2.0 1.2

7 163 74.9 

7 1,640 1,100 

7 12.9 9.7

7 2,420 826 

7 1.5 1.2

7 240 222

Hydropsvche spp.

2 1.7 1.6

2 2.1 1.4

2 140 104 

2 1,610 1,070

2 13.2 10.5

2 1,150 638 

2 1.6 1.6

1.2

1.7

105 

1,440 

11.0

2,070 

1.3

231

1.6

1.8

122 

1,340

11.8

892 

1.6

1.0

1.8

87.5 

1,500 

10.9

2,280 

1.3

231

~

~

2 212 191 202 

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for biological data: 1986-87, 1990-98

Arctopsyche grandis

2 2.4 <4.2 

2 1.0 <1.3

2 69.1 34.9

2 676 537 

2 <7.8 3.8

2 727 380 

2 <1.7 <1.3

2 178 140

Hydropsvche cockerelli

17 2.3 .8

17 3.2 .4

17 136 54.7 

1 7 3,340 490

17 18.2 4.3

17 1,030 396 

17 2.4 .3

17 391 132

'2.2 

'.8

52.0 

606

'3.8

554

l__

159

1.3

1.7

96.8 

1,180

8.9

683

1.2

186

--

--

--

1.3

1.9

102 

1,050

8.9

679 

1.1

184

TABLE 24 91
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Number of ,,

iVl fl.XI~ Constituent composite Minimum 

, mum samples

Mean Median

12324200-CLARK FORK AT DEER LODGE. MONT.-Continued

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Period of record for biological data: 1986-87, 1990-98

Hvdropsvche occidentalis

26 2.7 .8

26 2.6 .6

26 162 49.5 

26 1,930 558 1 

26 16.2 6.3

26 2,840 649 1 

26 12.9 1.0

26 299 196

Hvdropsvche spp.

3 2.0 1.2

0

3 222 103 

3 2,220 1,110 1 

3 15.0 5.6

0 

0

3 203 185

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON

Period of record for biological data: 1987, 1994, 1998

Arctopsvche grandis

10 .5 .2

10 1.6 .6

10 14.0 9.1 

10 654 177

10 1.3 .5

10 596 318 

10 .6 .4

10 179 113

Claassenia sabulosa

5 .5 .1

5 .9 .7

5 36.1 20.0 

5 319 98

5 <.7 <4

5 71.0 46.7

5 .7 .5

5 233 191

1.3

1.9

114 

,460 

11.4

,650 

1.9

235

1.6

-

145 

,520 

8.8

~

195

. MONT.

.3

.8

11.4 

284

.8

479

.5

149

.3

.8

29.5 

174

} -

57.8 

.6

205

1.3

2.0

111 

1,510 

11.1

1,740 

1.4

227

1.6

Ill 

1,240

5.7

~

197

.3

.8

11.5

235

.8

496

.5

145

.2

.8

31.4 

144

'--

56.7 

.5

202

92 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Number of 

Constituent composite 

samples

Maxi- ... . Minimum 

mum

Mean Median

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.-Continued

Period of record for biological data: 1987, 1994, 1998

Hydropsyche cockerelti

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

1

1

1

~

~

~

-

~

--

--

.6

1.6

28.4 

478

3.6

399 

1.2

123

~

--

Hvdropsvche occidentalis

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

2

2

2 

2

2

2 

2

<.7

2.3

15.2 

1,340

2.3

554 

1.1

.3

1.3

15.1 

426

<3.7

434 

.8

2 137 110 

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for biological data: 1992-98

.3

1.8

15.2 

883

2.1

494 

1.0

124

-

Arctopsvche grandis

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

17

17

17 

17

17

17 

17

17

6.6

3.3

129 

2,360

10.9

1,100 

1.8

309

1.4

.8

28.8 

339

2.3

592 

.2

165

2.4

1.5

58.7 

888

4.7

802 

.9

197

2.1

1.0

56.5 

651

3.8

760 

.8

186

Claassenia sabulosa

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

13

13

13 

13

13

13 

13

13

3.5

1.6

67.7 

296

1.7

179

.7

296

.6

.3

33.0 

63.0

.5

50.6 

.2

166

1.7

.7

53.6 

166

1.0

97.0 

.3

246

1.7

.6

50.6 

171

1.0

90.3 

.3

258

TABLE 24 93
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Number of ,. .

IVI 3.X I" Constituent composite Minimum 

, mum samples

Mean Median

12324680-CLARK FORK AT GOLDCREEK. MONT.-Continued

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Period of record for biological data: 1992-98

Hydropsvche cockerelli

13 2.6 .6

13 4.7 .7

13 188 33.5 

13 3,250 589 

13 16.2 4.5

13 954 538 

13 2.3 .6

13 240 137

Hydropsvche morosa group

4 1.7 1.1

4 1.4 1.3

4 72.9 43.8 

4 1,320 612 

4 6.9 2.4

4 1,030 538 

4 1.4 .9

4 190 137

Hydropsvche occidentalis

12 1.7 .7

12 3.9 .4

12 156 26.4 

12 2,720 466

12 15.7 2.9

12 1,800 530 

12 2.5 .8

1.7

2.5

95.4 

1,410

8.5

705 

1.4

194

1.4

1.4

60.5 

1,050 

4.6

804 

1.2

167

1.2

1.5

64.9 

1,140

7.0

1,060 

1.3

12 242 97 182 

12331500-FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for biological data: 1986, 1992-98

Arctopsvche grandis

33 .8 .1

33 4.7 .6

33 21.7 8.7 

33 2,460 606 

33 17.5 3.7

33 2,480 679 

33 2.7 .6

33 275 141

.4

1.9

14.9 

1,380 

8.7

1,470 

1.3

198

1.7

2.0

67.1 

1,340 

6.9

654 

1.3

201

1.4

1.4

62.7 

1,130 

4.6

822 

1.2

170

1.3

1.4

51.8 

931

6.0

984 

1.1

186

.4

1.8

14.9 

1,380

7.5

1,330 

1.2

188

94 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Number of 

Constituent composite Minimum 

. mum samples

Mean Median

12331500-FLINT CREEK NEAR DRUMMOND. MONT.-Continued

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Period of record for biological data: 1986, 1992-98

Hvdropsvche cockerelli

8 .7 .2

8 4.0 1.0

8 28.3 9.5 

8 3,290 996

8 17.9 3.1

8 1,440 401 

8 2.3 .9

8 193 85

Hvdropsvche occidentalis

6 1.0 .2

6 17.6 .7

6 26.4 15.1 

6 2,550 912

6 29.2 5.8

6 2,690 1,400 

6 6.9 .8

6 243 128

Hydropsyche tana

2 <\.2 <.\

2 10.3 .6

2 16.0 5.4 

2 1,320 729

2 15.3 5.0

2 1,400 1,180 

2 3.1 .5

.4

1.8

18.1 

1,780

11.3

1,020 

1.9

157

.6

4.6

19.3

1,720

17.7

1,860

3.2

182

'-

5.4

10.7 

1,020

10.2

1,290 

1.8

.4

1.5

18.1 

1,680

12.0

1,130 

2.2

180

.6

1.8

18.0 

1,780

19.3

1,760 

2.9

185

~

~

2 139 107 123 

12331800-CLARK FORK NEAR DRUMMOND. MONT.

Period of record for biological data: 1986, 1991-98

Arctopsvche grandis

22 3.8 .7

22 2.5 .2

22 89.2 18.2 

22 1,660 240

22 11.8 2.1

22 2,010 462 

22 1.9 .2

22 308 142

1.7

1.1

38.8 

671

5.0

861

.7

194

1.5

1.0

34.0 

613

4.3

721 

.7

189

TABLE 24 95
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Number of 

Constituent composite 

samples

Maxi- ... . Minimum 

mum

Mean Median

12331800-CLARK FORK NEAR DRUMMOND. MONT.-Continued

Period of record for biological data: 1986, 1991-98

Clnnssenia, sobulosa,

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

27

27

27 

27

27

27 

27

27

2.8 .3

3.3 .3

130 18.0 

290 76.1

2.2 .2

270 45.9 

1.1 .1

469 140

1.4

.8

60.4 

138

.8

128 

.3

258

1.4

.6

52.6

117

.8

125 

.2

241

Hvdropsvche cockerelli

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

16

16

16 

16 

16

16 

16

16

2.3 .7

3.5 .4

156 37.9 

2,500 506 

15.0 5.1

982 549 

2.0 .5

240 164

1.6

1.9

78.3 

1,350 

9.1

760 

1.2

197

1.7

1.7

68.0 

1,180 

8.0

743 

1.1

195

Hvdropsvche morosa group

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

6

6

6 

6 

6

6 

6

6

1.3 1.1

2.8 1.9

57.4 50.2 

1,730 1,380 

10.8 7.0

1,940 1,260 

1.7 1.3

250 227

1.2

2.3

55.2 

1,570 

8.9

1,610 

1.5

239

1.2

2.2

55.8 

1,600 

9.0

1,620 

1.5

240

Hvdropsvche occidentalis

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

12

12

12 

12 

12

12 

12

12

2.0 .7

8.1 .4

118 13.3 

2,060 424 

13.5 2.9

2,920 619 

2.4 .5

283 157

1.2

2.5

56.8 

1,240

8.7

1,450 

1.4

217

1.2

2.1

54.7 

1,230 

8.7

1,160 

1.5

212

Hvdropsvche spp.

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

1

0

1 

1

1

0 

0

1

..

..

..

2.6

85.0 

940

9.1

260

~

96 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for steams in the 

Upper Clark Fork Basin, Montana
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Constituent

Number of 

composite 

samples

Maxi- ... . Minimum 

mum

Mean Median

12334510-ROCK CREEK NEAR CLINTON. MONT.

Period of record for biological data: 1987, 1991-98

Arctopsvche frandis

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

31

31

31 

31 

31

31

31

31

.4 .06

2.9 .5

15.7 4.7 

991 191 

<2.9 .1

454 113 

1.6 .2

189 84

.2

1.2

8.7

537

u

253 

.8

127

.2

1.0

8.5 

546 

U

227 

.8

125

Claassenia sabulosa

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

16

16

16 

16

16

16 

16

16

.3 .05

1.8 .4

40.7 18.1 

129 49.8

1.0 .1

76.3 15.7 

.9 .1

264 164

Hvdropsvche cockerelli

3 <.2 <.2

3

3 

3

3

3

3

3

1.0 .9

13.1 6.0 

609 485

<1.1 <1.1

258 192 

.9 .4

99 82

.2

.8

29.8 

90.7

.3

35.0 

.3

205

I..

.9

8.6 

530

' 

219 

.6

89

.1

.6

30.0 

93.1

.3

33.6 

.3

207

<2

.9

6.6 

497

<1.1

208 

.4

86

Hvdropsvche occidentalis

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

4

4

4 

4

4

4 

4

4

<1.0 <.3

2.4 .9

17.6 9.6 

752 520

6.0 1.2

268 169 

1.7 .6

144 99

L.

1.6

12.0 

642

3.0

228 

1.2

121

<.3

.9

10.2 

648

1.2

215 

.9

117

TABLE 24 97
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of .

Constituent composite Minimum Mean mum samples

12334510-ROCK CREEK NEAR CLINTON. MONT.-Continued

Period of record for biological data: 1987, 1991-98

Hvdropsyche spp.

3 .3 <5 '.2

3 2.1 1.1 1.6

3 16.2 11.6 14.3

3 1,140 837 1,000

3 <3.1 <1.8 ] -

3 462 299 399

3 1.3 .8 1.1

3 135 117 126

12334550-CLARK FORK AT TURAH BRIDGE. NEAR BONNER. MONT.

Period of record for biological data: 1986, 1991-98

Arctopsvche grandis

29 2.7 .6 1.4

29 4.1 .6 1.7

29 125 20.1 41.6

29 2,870 420 1,030

29 13.2 2.1 4.5

29 893 351 616

29 2.6 .4 1.0

29 276 152 198

Claassenia sabulosa

22 2.5 .3 1.2

22 2.0 .4 .8

22 79.2 38.3 57.7

22 181 58.6 106

22 1.6 .2 .6

22 139 42.0 78.6

22 .6 .1 .2

22 283 144 223

Hvdropsvche cockerelli

20 1.7 .6 1.0

20 8.0 1.0 2.2

20 118 26.4 52.0

20 2,530 688 1,260

20 12.1 2.2 5.4

20 788 426 580

20 2.6 .6 1.2

20 228 148 184

Medhn

.2

1.7

15.0

1,030

<2.9

437

1.1

126

1.5

1.6

33.8

867

3.3

616

.8

196

.9

.6

55.6

104

.6

69.7

.2

232

.8

1.7

42.4

1,060

4.9

554

1.1

180

98 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Number of ,. . 

,-, . . Maxi- ... . Constituent composite Minimum , mum samples

12334550-CLARK FORK AT TURAH BRIDGE. NEAR BONNER.

Mean

MONT.-Continued

Median

Period of record for biological data: 1986, 1991-98

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Hvdropsvche morosa group

2 1.3 1.1

2 4.6 2.4

2 84.1 26.8 

2 1,800 986

2 6.6 <7.8

2 1,320 537 

2 1.7 1.3

2 231 171

Hvdropsvche occidentalis

14 1.8 .3

14 3.1 .6

14 102 34.1 

14 2,310 472

14 12.2 3.0

14 1,510 454 

14 1.9 .6

14 235 145

Hydropsyche spp.

..

1

1.2

3.5

55.4 

1,390

5.2

928 

1.5

201

.9

1.8

48.6 

1,100

5.7

758 

1.0

188

1.3

2.4

84.1 

1,800

<7.8

537 

1.3

~

~

~

--

.8

1.5

40.5 

975

5.3

665 

.9

177

~

~

1 -- - 171 

12340000-BLACKFOOT RIVER NEAR BONNER. MONT.

Period of record for biological data: 1986-87, 1991, 1993, 1996, 1998

Cadmium

Chromium 

Copper 

Iron

Lead

Manganese 

Nickel 

Zinc

Arctopsvche frandis

9 .3 <.l

3 1.8 1.2 

9 2 13.4 9.9 

9 1,230 108

9 2.1 .5

3 517 389 

3 1.2 .8 

9 2 143 123

'.2

1.4 

11.8 

596

1.2

435 

1.0 

134

'.2

1.3 

12.0 

617-

.9

398 

.9 

135

TABLE 24 99
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Number of ,. 

_ A .A A .. Maxi- Constituent composite 

, mum samples

Minimum Mean Median

12340000-BLACKFOOT RIVER NEAR BONNER. MONT.-Continued

Period of record for biological data: 1986-87, 1991, 1993,

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Claassenia sabidosa

9 2 .2

3 .9

9 88.5 

9 199

9 .6

3 127 

3 .3

9 329

Hydropsyche occidentalis

12 .5

12 2.7

12 20.6 

12 1,930 

12 1.9

12 527 

12 1.8

12 150

Hvdropsvche spp.

1

1

1 

1

1

1 

1

1

.1

.5

19.0 

68.0

.4

44.2 

.1

117

.1

.8

12.0 

1,050 

.8

414 

.9

117

--

1996, 1998

.1

.7

44.5 

124

.5

74.6 

.2

204

.2

1.8

14.6 

1,410 

1.3

472 

1.3

134

.6

1.6

13.9 

1,120

2.9

525 

2.8

132

.1

.7

41.0 

114

.6

52.6

.2

194

.2

1.7

14.4 

1,380 

1.2

460 

1.2

130

--

__

100 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Constituent

Number of ,_ . Maxi- . composite Minimum 

. mum samples

Mean Median

12340500-CLARK FORK ABOVE MISSOULA. MONT.

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Period of record for biological data: 1997-98

Arctopsvche grandis

8 1.8 .5

8 3.0 1.3

8 77.6 22.3 

8 2,340 708 

8 6.8 1.2

8 929 476 

8 2.0 .7

8 235 155

Claassenia sabulosa

2 2.0 1.7

2 1.1 .5

2 51.0 37.8 

2 136 95.3

2 <3.8 <1.4

2 111 75.2 

2 <9 <.3

2 273 226

Hydropsvche cockerelli

5 1.3 1.0

5 4.1 3.1

5 96.1 45.7 

5 3,590 2,040 

5 6.3 5.3

5 1,180 781 

5 2.4 1.4

5 226 191

Hydropsvche occidentalis

2 1.1 1.0

2 2.9 2.8

2 76.5 49.8 

2 2,240 2,010 

2 7.7 7.1

2 2,030 939 

2 2.1 1.9

2 232 210

1.0

1.7

35.7 

1,200 

3.6

701 

1.1

181

1.8

.8

44.4 

116

'--

93.1

250

1.1

3.4

71.9 

2,560 

5.8

930 

1.9

208

1.0

2.8

63.2 

2,120 

7.4

1,480 

2.0

221

.9

1.6

26.7 

1,050 

3.5

704 

.9

175

--

--

1.1

3.3

83.5 

2,430 

5.9

878 

1.9

207

--

~

-

12353000--CLARK FORK BELOW MISSOULA. MONT.3

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Period of record for biological data: 1986, 1990-98

Arctopsvche grandis

17 1.5 .3

17 2.7 .5

17 38.0 9.4 

17 1,500 343

17 3.2 .9

17 1,090 511 

17 1.6 .4

17 184 106

.7

1.4

21.0

779

1.8

691 

.9

146

.6

1.4

20.3 

754

1.9

681 

.9

145

TABLE 24 101
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1998 (Continued)

Constituent

Number of 

composite 

samples

MaxiMinimum Mean mum

Median

12353000--CLARK FORK BELOW M1SSOULA. MONT.3-Continued 

Period of record for biological data: 1986,1990-98

Claassenia sabulosa

Cadmium 

Chromium 

Copper 

Iron

Lead

Manganese

Nickel

Zinc

29 

29 

29 

29

29

29

29

29

1.3 .2 

1.2 .05 

61.5 31.1 

240 66.6

1.3 .1

168 48.9

.3 .1

286 146

.6

.5 

46.4 

106

.4

98.6

.2

206

.5 

.5 

46.5 

95.0

.3

93.0

.2

202

Hydropsyche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

26

26

26

26

26

26

26

26

1.1 .2

3.4 .8

45.7 12.4

2,000 645

3.6 1.2

1,180 353

1.7 .5

172 77.4

.5

2.0

30.0

1,270

2.3

709

1.2

145

.6

1.9

31.0

1,270

2.3

659

1.3

154

Hydropsvche occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

11

11

11

11

11

11

11

11

1.1 .2

3.5 .2

38.2 18.9

1,420 482

4.2 .7

1 ,460 667

2.2 .5

193 116

Hvdropsvche spp.

..

..

..

..

-

--

.5

1.5

26.3

950

2.2

895

1.1

144

.5

.8

20.8

894

1.1

756

1.1

124

.5

1.6

27.6

901

2.0

834

1.0

145

--

--

--

--

Values determined by arbitrarily substituting one-half of the detection level for censored (<) values, when both 

uncensored and censored values are used in determining the mean. When all data are below the detection level, the 

median is determined by ranking the censored values in order of detection level. No mean is reported when all values 

are below the detection level.

2 Samples collected at alternate sampling site deleted from sample set in 1998 resulted in a lower maximum value thar 

previously reported at Blackfoot River near Bonner.

Samples collected about 30 miles downstream from water-quality station to conform to previous sampling location.

102 Water-quality, bed-sediment, and biological data (October 1997 through September 1998) and statistical summaries of data for streams In the 

Upper Clark Fork Basin, Montana

->i:-S. GOVERNMENT PRINTING OFHCE;I999-77d-2J7/OJ<W4