In cooperation with the

U.S. ENVIRONMENTAL PROTECTION AGENCY

Water-Quality, Bed-Sediment, and Biological 

Data (October 2000 Through September 2001) 

and Statistical Summaries of Data for Streams 

in the Upper Clark Fork Basin, Montana

By Kent A. Dodge, Mi c he Me I. Hornberger, and 

Carlos Primo C. David

Open-File Report 02-358

U.S. Department of the Interior 

U.S. Geological Survey

Helena, Montana 

October 2002
U.S. Department of the Interior

GALE A. NORTON, Secretary

U.S. Geological Survey

Charles G. Groat, Director

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

purposes only and does not imply endorsement by the U.S. Government

For additional information 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................................................................................................................................................. 13

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

Data................................................................................................................................................................. 16

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 2000 through September 2001........ 17

5-7. Daily streamflow and suspended-sediment data, October 2000 through September 2001, for:

5. Clark Fork at Deer Lodge, Montana.................................................................................................... 32

6. Clark Fork at Turah Bridge, near Bonner, Montana............................................................................ 36

7. Clark Fork above Missoula, Montana.................................................................................................. 40

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

basin, Montana............................................................................................................................................ 44

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

Clark Fork basin, Montana......................................................................................................................... 45

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

Montana...................................................................................................................................................... 46

11. Recovery efficiency for trace-element analyses of laboratory-spiked deionized-water blanks..................... 47

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

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

13. Chemical analyses of field blanks for water samples.................................................................................... 49

14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, August 2001..... 50

15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, August 2001.................. 51

16. Recovery efficiency for trace-element analyses of standard reference materials for bed sediment.............. 52

17. Trace-element analyses of procedural blanks for bed sediment.................................................................... 53

CONTENTS iii
TABLES (Continued)

Page

Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 2001 ...................................... 54

19. Recovery efficiency for trace-element analyses of standard reference material for biota............................ 56

20. Trace-element analyses of procedural blanks for biota................................................................................. 57

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

through September 2001............................................................................................................................ 58

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

August 1986 through September 2001....................................................................................................... 73

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

1993 through September 2001................................................................................................................... 78

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

through September 2001....................................... ................................................................................... 82

CONVERSION FACTORS, DATUM, ABBREVIATED WATER-QUALITY UNITS, AND ACRONYMS

Multiply

cubic foot per second (ft3/s)

foot (ft)

gallon (gal)

gallon (gal)

inch (in.)

inch (in.)

mile (mi)

ounce (oz)

part per million

square mile (mi2)

ton per day (ton/d)

By

0.028317

0.3048

3.785

3,785

25.4

25,400

1.609

28.35

1

2.59

907.2

To obtain

cubic meter per second

meter (m)

liter (L)

milliliter (mL)

millimeter (mm)

micrometer (urn)

kilometer

gram (g)

microgram per gram (ug/g)

square kilometer

kilogram per day

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

°F = 9/5 (°C) + 32 

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 (NGVD 29)

Horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 27).

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.

Acronyms used in the report:

ICAPES Inductively Coupled Argon Plasma Emission Spectroscopy RSD relative standard deviation

LRL laboratory reporting level SRM standard reference material

LT-MDL long-term method detection level USGS U.S. Geological Survey

NWQL USGS National Water Quality Laboratory, Denver, Colo.

iv Water-Quality, Bed-Sediment, and Biological Data (October 2000 through September 2001) and Statistical Summaries of Data for Streams in 

the Upper Clark Fork Basin, Montana
Water-Quality, Bed-Sediment, and Biological Data (October 

2000 through September 2001) and Statistical Summaries of 

Data for Streams in the Upper Clark Fork Basin, Montana

By Kent A. Dodge, Michelle I. Hornberger1 , and Carlos Prime C. David1

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 2000 through 

September 2001 (water year 2001). Data for 16 bedsediment and 15 biological stations were obtained in 

August 2001. 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 

suspended-sediment discharge are given for three 

stations. Bed-sediment 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. Qualityassurance data are reported for analytical results of 

water, bed sediment, and biota. Statistical summaries 

of water-quality, 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-mi 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 were 

prevalent land uses in the upper basin for more than one 

hundred years, but are now largely discontinued.

Deposits of copper, gold, silver, and lead 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, transported downstream, 

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, and redeposited along the stream 

channel and flood plain, especially during high flows. 

The occurrence of trace elements in elevated 

concentrations can pose a risk to aquatic biota and 

human health because they can 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. Waterquality data have been collected by the U.S. Geological 

Survey (USGS) at selected sites in the upper Clark Fork 

basin since 1985 (Lambing, 1987, 1988, 1989, 1990,

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

Abstract
114

MONTANA

p Helena 

Study area

Base modified from U.S. 

Geological Survey, State 

base map, 1:1,000,000, 

1966. North American 

Datum of 1927 (NAD 27)

EXPLANATION 

12324200 STATION NUMBER

461903112440701 MISCELLANEOUS SITE NUMBER 

STREAMFLOW STATION TYPE 

A Continuous record 

A Periodic measurement

WATER QUALITY, BED SEDIMENT, 

AND BIOTA STATION TYPE

^7 Periodic water quality 

^. Daily suspended sediment 

^7~ Once-annual bed sediment 

~V Once-annual biota

46°

461903112440701 -n461559112443301 ~^~ 

461415112450801~V

.V12323800- £

VV.imi Snnnr, -V ' §

12323770A -5f|- 12323750 ^l ij,,-, i^o^o//u» TT3~ ^^c^-^j^r^

»nscor.#r"1* A

opr-n,.,**^ 12323600 sr"|

20 MILES

10 20 KILOMETERS

Figure 1. Location of study area.

and 1991; Lambing and others, 1994,1995; and Dodge 

and others, 1996, 1997, 1998, 1999, 2000, 2001). 

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 bedsediment 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 by the USGS in cooperation with the U.S.

Environmental Protection Agency to provide 

systematic, long-term monitoring to better quantify the 

seasonal and annual variability in selected constituents.

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

16 bed-sediment and 15 biological stations in the upper 

Clark Fork basin collected from October 2000 through 

September 2001 (water year 2001). 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.

2 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
SAMPLING LOCATIONS AND TYPES OF 

DATA

Sampling stations in the upper Clark Fork basin 

are located on the Clark Fork mainstem and major 

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

stations, types of data collected, and period of record 

for each data type are listed in table 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. Traceelement data for 16 bed-sediment and 15 biological 

stations were obtained once-annually. Continuous 

streamflow data were collected at 15 stations.

A list of properties measured onsite 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 data for water year 2001 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 2001 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 chemical and 

physical constituents analyzed in stream samples. 

Samples were collected 6 to 8 times per year on a

schedule designed to describe seasonal and hydrologic 

variability.

Methods

Cross-sectional water samples were collected 

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

(1985), Ward and Harr (1990), Wilde and others 

(1998), and Edwards and Glysson (1999). These 

methods provide a vertically and laterally dischargeweighted composite sample that is representative of the 

entire flow through the cross section of a stream. 

Sampling equipment consisted of standard USGS 

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

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

and equipped with nylon nozzles.

Onsite measurements of air and 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 Knapton (1985), Ward and Harr (1990), 

Horowitz and others (1994) and Wilde and others 

(1998). 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 Denver, 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 

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

SAMPLING LOCATIONS AND TYPES OF DATA
8? E 5?

? a 

2 3

Is

a &

IQ sC/3

g, a

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)

123232301232325012323600

12323750

1232377012323800

461415112450801461559112443301461903112440701

12324200

12324590

12324680

1233150012331800

12334510

12334550

12340000

12340500

12353000

Station name

Blacktail Creek at Harrison Avenue, at Butte

Silver Bow Creek below Blacktail Creek, at 

ButteSilver Bow Creek at OpportunitySilver Bow Creek at Warm Springs

Warm Springs Creek at Warm Springs

Clark Fork near GalenClark Fork below Lost Creek, near Galen

Clark Fork near RacetrackClark Fork at Dempsey Creek diversion, near RacetrackClark Fork at Deer Lodge

Little Blackfoot River near Garrison

Clark Fork at GoldcreekFlint Creek near Drummond

Clark Fork near Drummond

Rock Creek near ClintonClark Fork at Turah Bridge, near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula4

Continuousrecord 

streamflow -- 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

wm-p

08/90-P04/93-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-P03/93-P07/88-P

 -- 03/85-P

03/85-P03/93-P

03/85-P03/93-P

03/85-P

03/85-P03/85-P

07'86-PJ

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, 08/99

08/87, 

08/9 1-P08/96-P08/96-P08/96-P

08/86, 08/87, 

08/90-P

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

08/98, 08/01

07/92-P

08/86, 08/89, 

07/92-P

08/86, 08/87, 

08/91-P

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

08/91-99,08/01

08/86, 

08/91-P

08/86, 08/87, 

08/91, 

08/93-96. 08/98-P

08/97-P

08/86, 

08/90-P

Bulk bed sediment2

08/93-08/95, 

08/97-P

08/93, 

08/95-P

08/95, 08/97, 08/99

08/93-P

08/96-P08/96-P08/96-P08/93-P

08/94, 08/98, 08/01

08/93-P08/93-P08/93-P

08/93-99, 08/01

08/93-P

08/93, 08/94, 08/99-P

08/97-P08/93-P

Biota2

07/92, 08/94, 

08/95, 08/97-P

07/92-P

08/95, 08/97, 08/99

08/87, 

08/91-P

08/96-P08/96-P08/96-P

08/86, 08/87. 

08/90-P

08/87, 08/94 

08/98, 08/01

07/92-P

08/86, 

07/92-P

08/86, 

08/91-P

08/87, 

08/91-99,08/01

08/86, 

08/91-P

08/86, 08/87, 08/91,08/93, 

08/96, 08/98, 09/00

08/97-P

08/86, 

08/90-P

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

elements and suspended sediment, with the exception of Clark Fork below Missoula. 

laboratory analyses of trace elements.

3Prior to October 1989 water-quality data for Clark Fork above Missoula only included suspended-sediment data. 

4Bed sediment and biota sampled about 30 miles downstream from streamflow-gaging station to conform to previous sampling location. Water-quality sampling discontinued in 1995.
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

2 to 8 times per week. These samples were collected 

by local contract 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 2000 through September 

2001 (water year 2001) 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 2001 at the three daily suspendedsediment 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 Ward and Harr (1990), 

Knapton and Nimick (1991), Horowitz and others 

(1994), Wilde and others, (1998), and Edwards and 

Glysson (1999). 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 (1995). 

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 routine 

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.

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, 1995). These internal practices include 

analyses of quality-control samples such as calibration

WATER-QUALITY DATA
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 USGS 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 (field replicate) by either repeating the collection 

process to obtain two or more independent composite 

samples, or by splitting a single composite sample into 

two or more subsamples. The individual replicate 

samples are then analyzed separately. 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, replicate stream 

samples for chemical analysis were obtained in the 

field by splitting a composite stream sample, and 

replicate stream samples for suspended-sediment 

analysis 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 analyzed 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 samples 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 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

6 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

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

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

Data-quality objectives

Detectability

Constituent

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)

Precision

Maximum relative 

Laboratory standard deviation of 

reporting laboratory replicate 

level1 analyses,

0.01

.008

2

.2

.10-. 11

.10-. 14

.6

1.0-1.3

10

10

1

1

3

.1-1

1

1

1

1

mg/L

mg/L

Hg/L

Hg/L

Hg/L

Hg/L

Hg/L

Hg/L

Hg/L

Hg/L

Hg/L

Hg/L

Hg/L

Hg/L

Hg/L

Hg/L

mg/L

percent

in percent

20

20

20

20

20

20

20

20

20

20

20

20

20

20

20

20

-

-

Bias

Maximum 

deviation of 

spike recovery, 

in percent

-

-

25

25

25

25

25

25

25

25

25

25

25

25

25

25

-

-

For those constituents showing a range of values, the laboratory reporting level changed during water year 2001.

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.

During water year 1999, the NWQL began 

implementation of a new, statistically based convention 

for establishing reporting levels and for reporting lowconcentration data (Childress and others, 1999). 

Quality-control data are collected on a continuing basis 

to determine long-term method detection levels (LTMDLs) and laboratory reporting levels (LRLs). These 

values are re-evaluated each year and, consequently, 

may change from year to year. The methods are 

designed to limit the possible occurrence of a false 

positive or false negative error to 1 percent or less.

Accordingly, concentrations are reported as less than 

the LRL for samples in which the analyte was either not 

detected or did not pass identification criteria. 

Analytes that are detected at concentrations between 

the LT-MDL and LRL and that pass identification 

criteria are estimated. Estimated concentrations are 

noted with a remark code of "E." These data need to 

be used with the understanding that their uncertainty is 

greater than that of data reported without the "E" 

remark code.

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. These 

replicate measurements may consist either of 

individual analyses of a pair of samples considered to 

be essentially identical (field replicates) or multiple 

analyses of an individual sample (laboratory 

replicates). The differences in concentration between

WATER-QUALITY DATA
replicate analyses can be used to estimate a standard 

deviation according to the following equation (Taylor, 

1987):

S = (1)

where

S =

d =

k =

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.

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 = 3 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. The 

data-quality objective used to evaluate precision of 

results for field replicates was a maximum relative 

standard deviation of 20 percent. Precision estimates 

for the field replicate analysis were within the 20- 

percent relative standard deviation limit 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 totalrecoverable cadmium and dissolved lead. The 

exceedance of the data quality objective for both 

constituents does not necessarily impact precision as 

both exceedances were artifacts of comparing 

analytical results that were below detection capabilities 

of laboratory equipment and methodology.

Analyses of an unspiked sample and a spiked 

aliquot of the same sample provide a measure of the 

recovery efficiency for the analytical method within 

the chemical matrix of the sample. 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. The differences between the 

spiked and unspiked sample concentrations were 

determined and used to compute recovery, in percent, 

according to equation 3 below:

Spike recovery, in percent =

spiked sample concentration - unspiked sample concentration 

spike concentration xlOO (3)

Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
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 deionizedwater samples spiked with trace elements ranged from 

96.4 to 107.9 percent. The mean spike recovery for 

spiked stream samples ranged from 91.8 to 106.8 

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 total-recoverable copper (87.7- 

95.9), dissolved copper (104-110), and totalrecoverable lead (95.3-99.3) percent. Because the 

mean spike recoveries for all constituents met dataquality 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 LRL 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 LRL (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 were evaluated for a 

consistent trend that may indicate systematic 

contamination. Sporadic, infrequent exceedances of 

twice the LRL 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 LRL 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 LRL. Total-recoverable 

zinc had one minor exceedance of the LRL. There 

were no exceedances of LRLs for the same constituent 

in consecutive samples. Therefore, the analytical 

results for field blanks indicate no systematic 

contamination that would bias the reported waterquality 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 and the same season 

(typically August) to facilitate data comparisons 

among years.

Methods

Bed-sediment samples were collected in August 

2001 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 two composite samples 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 

times to obtain three composite samples. Each 

composite sample was wet-sieved onsite through a 

0.064-mm nylon-mesh 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

BED-SEDIMENT DATA
of three to five randomly selected deposits. The 

individual samples were combined to form a single 

composite sample. Because the streambed at most 

sampling locations is predominantly gravel and cobble, 

deposits were selected where cobbles and gravel could 

be excluded from the samples. Bulk bed-sediment 

samples were not sieved and generally were composed 

of particles smaller than about 10 mm in diameter. The 

individual unsieved samples were composited into an 

acid-washed polyethylene bottle and transported to the 

laboratory on ice.

Bed-sediment samples were prepared for analysis 

at the USGS National Research Program laboratory in 

Menlo Park, Calif. Fine-grained and bulk bedsediment 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 0.6N (normal) hydrochloric acid. The 

reconstituted aliquots then were filtered through a 0.45- 

[im filter using a syringe and in-line disposable filter 

cartridge. The filtrate was subsequently diluted to 

either a 2:10,3:10, or 5:10 ratio with 0.6N hydrochloric 

acid. These final solutions were 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 2001 are summarized in tables 

14 and 15, respectively. Liquid-phase concentrations, 

in |ag/mL, that were analyzed in the reconstituted 

aliquots of digested bed sediment were converted to 

solid-phase concentrationsjn f-lg/g, using the following 

equation:

= iig/mL x volume of digested sample, in mL (4) 

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 and 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 laboratory-grade 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, U.S. Geological 

Survey, 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 number of bed-sediment samples.

Standard reference materials (SRMs) are 

commercially prepared materials that have certified 

concentrations of trace elements. Replicate analyses of 

SRMs are used to indicate the reproducibility of 

analytical results and the ability of the method to 

accurately measure a known quantity of a constituent. 

Recovery efficiency of trace-element analyses of 

SRMs for bed sediment is summarized in table 16. 

Two SRMs 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"

10 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
digestion (does not liberate elements 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 

SRMs when using less than a total digestion is useful to 

indicate which trace elements display strong sedimentbinding characteristics and whether analytical recovery 

is consistent between multiple sets of analyses.

Although data-quality objectives have not been 

established for bed sediment, percent recoveries are 

shown in table 16 to illustrate analytical performance. 

Chromium for both low-concentration range (SRM 

2709) and high-concentration range (SRM 2711) 

showed consistently low recoveries (76.4 and 47.6 

percent, respectively). Zinc in SRM 2709 also 

displayed low recovery (71.8 percent). Cadmium and 

silver were below the analytical detection limit in SRM 

2709. The reason for the lack of measurable recoveries 

for the low-range cadmium and silver is believed to be 

the result of analyzing concentrations very close to the 

detection limit coupled with signal enhancement 

resulting from matrix interference. Mean recoveries 

for all other constituents in both low and high 

concentration SRMs ranged from about 80 to 103 

percent; thus, they were within 20 percent of complete 

recovery. 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, 0.6N hydrochloric acid 

was added to the dry residue. Procedural blanks, 

therefore, represent the same chemical matrix as the 

reagents used to digest and reconstitute bed-sediment 

samples. No dilution of the reagents is made prior to 

analysis in order to maximize and detect any 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 ug/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 [ig/g, relative to the ambient 

concentration of the trace element in bed-sediment 

samples. If a detectable blank concentration represents

10 percent or more of the ambient solid-phase 

concentration, then the blank concentration is 

subtracted to remove potential contamination bias. 

Two procedural blanks showed metal concentrations 

(for iron and zinc) above the analytical detection limit. 

However, both represented less than 1 percent of the 

ambient concentration in environmental samples; 

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 traceelement concentrations in the whole-body tissue of 

aquatic benthic insects. Insect samples are collected 

once-annually at the same sites and dates as bedsediment samples (table 1), allowing for a direct 

comparison of biological data among years and with 

bed-sediment data.

Methods

Insect samples were collected using protocols 

described in Hornberger and others (1997). Immature 

stages of 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., Brachycentrus spp., and 

Arctopsyche grandis of the Order Trichoptera 

(caddisflies), and Claassenia sabulosa of the Order 

Plecoptera (stoneflies). Samples of each taxon were 

sorted by genus and placed in acid-washed plastic 

containers. Samples were frozen on dry ice within 30 

minutes of collection in a small amount of ambient 

river water. In previous years (1986-98), benthic 

insects were depurated for a period of 6-8 hours in an 

effort to evacuate gut contents. In 1998, a comparison 

of samples collected using both methods showed no 

significant difference in metal concentrations in 

benthic insects, with the exception of copper. Average 

copper concentrations in depurated samples were 8-25 

percent lower than samples frozen within 30 minutes of 

collection (M.I. Hornberger, unpub. data, 2000). The 

change in the field protocol minimizes the chance of 

metal loss through cell membranes during depuration

BIOLOGICAL DATA 11
and is consistent with methods established by Cain and 

Luoma (1998). However, caution should be exercised 

in comparing recent copper data for insects with earlier 

data because of the possibility of higher concentrations 

resulting from the change in field protocol.

Insect samples were processed and analyzed at 

the USGS National Research Program laboratory in 

Menlo Park, Calif. Insects were thawed and rinsed 

with ultra-pure deionized water to remove particulate 

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 concentrated 

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

insect samples were evaporated to dryness on a hot 

plate. The dry residue was reconstituted in 0.6N 

hydrochloric acid, filtered through a 0.45-|J,m filter, and 

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 2001 

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 with 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 targeted for 

collection in this study due to their occurrence at most, 

but not all, sites: Hydropsyche occidentalis and 

Hydropsyche cockerelli. Hydropsyche 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. 

Arctopsyche grandis, Brachycentrus spp., and 

Claasenia sabulosa also were collected, where 

available, to represent additional insect taxa that are 

fairly widely distributed in the upper Clark Fork basin.

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 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 SRM 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-element analyses of 

the SRM for biota is summarized in table 19. The 

reference material tested was 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 11 percent of certified values 

for cadmium, copper, nickel, and zinc. Recoveries for 

chromium, iron, and manganese were within 21 

percent. Lead recoveries could not be measured due to 

the very low solution concentration of lead in the biota 

standard (less than 10 parts per billion). Additionally, 

a quality-control standard with a similar solution 

concentration as the SRM samples was analyzed 

throughout the analysis. Recoveries for all reported 

elements were within 10 percent of the quality-control 

standard. No adjustments were made to the traceelement concentrations for the insect samples on the 

basis of recovery efficiency.

12 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
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 blanks were 

analyzed undiluted at a proportion of one blank per site. 

Analytical results for all blanks were less than 

detection; thus, no contamination bias was indicated.

STATISTICAL SUMMARIES OF DATA

Statistical summaries of water-quality, bedsediment, and biological data are provided in tables 21 - 

24 for the period of record at each station since 1986. 

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 

collected 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, near Bonner, Blackfoot 

River near Bonner, and Clark Fork above Missoula 

from 1997 to 1999. Inclusion of supplemental sample 

results targeted for high-flow conditions or 

maintenance drawdowns of Milltown Reservoir would 

disproportionately skew the long-term statistics at 

these three sites relative to the other sites in the 

network. 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 a compilation of single annual mean 

concentrations determined from the combined results 

of multiple composite samples for a given year. 

Therefore, sample sizes for bed sediment represent the 

number of years sampled. In contrast, sample sizes and 

statistics for biological data are based on individual 

analyses for each composite sample collected in an 

individual year, rather than on a single annual mean 

concentration from all composites combined. Biota 

sample sizes reflect differences in species abundances 

at each site and among all years. As a result, the 

statistics for biota describe a wider range of variation in 

trace-element concentrations than would be evident if 

results from individual composite samples were

averaged. 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 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 between 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 finegrained sediment of the Clark Fork River, 

Montana: Applied Geochemistry, v. 6, p. 75-88.

Cain, D.J., and Luoma, S.H., 1998, Metal exposures to 

native populations of the caddisfly Hydropsyche 

(Trichoptera: Hydropsychidae) determined from 

cytosolic and whole body metal concentrations: 

Hydrobiologia, v. 386, p. 103-117.

Cain, D.J., Luoma, S.N., and Axtmann, E.V., 1995, 

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.

Childress, C.T., Foreman, W.T., Connor. B.F., and 

Maloney, T.J., 1999, New reporting procedures 

based on long-term method detection levels and 

some considerations for interpretations of waterSTATISTICAL SUMMARIES OF DATA 13
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Dodge, K.A., Hornberger, M.I., and Axtmann, E.V.,

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data (October 1994 through September 1995) and 

statistical summaries of data for streams in the 

upper Clark Fork basin, Montana: U.S. Geological Survey Open-File Report 96-432, 109 p. 

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

1997. Water-quality, bed-sediment, and biological 

data (October 1995 through September 1996) and 

statistical summaries of data for streams in the 

upper Clark Fork basin, Montana: U.S. 

Geological Survey Open-File Report 97-552,91 p. 

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data (October 1996 through September 1997) and 

statistical summaries of data for streams in the 

upper Clark Fork basin, Montana: U.S. Geological Survey Open-File Report 98-407, 102 p. 

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1999. Water-quality, bed-sediment, and biological 

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statistical summaries of data for streams in the 

upper Clark Fork basin, Montana: U.S. Geological Survey Open-File Report 99-251, 102 p. 

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data (October 1998 through September 1999) and 

statistical summaries of data for streams in the 

upper Clark Fork basin, Montana: U.S. Geological Survey Open-File Report 00-370, 102 p. 

Dodge, K.A., Hornberger, M.I., and David, C.P.C.,

2001. Water-quality, bed-sediment, and biological 

data (October 1999 through September 2000) and 

statistical summaries of data for streams in the 

upper Clark Fork basin, Montana: U.S. 

Geological Survey Open-File Report 01 -379,95 p.

Edwards, T.K., and Glysson, GD., 1999, Field methods 

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Geological Survey Techniques of WaterResources Investigations, book 3, chap. C2, 89 p.

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

U.S. Geological Survey National Water Quality 

Laboratory Determination of inorganic and 

organic constituents in water and fluvial 

sediments: U.S. Geological Survey Open-File 

Report 93-125, 217 p.

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

Methods for determination of inorganic 

substances in water and fluvial sediments: U.S. 

Geological Survey Techniques of WaterResources Investigations, book 5, chap. Al, 

545 p.

Friedman, L.C., and Erdmann, D.E., 1982, Quality 

assurance practices for the chemical and biological 

analyses of water and fluvial sediments: U.S. 

Geological Survey Techniques of WaterResources 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.

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.

Hornberger, 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 surface-water 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.

14 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

npper Clark Fork basin, Montana
Lambing, J.H., 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.

Lambing, J.H., 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.

Lambing, J.H., 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.

Lambing, J.H., 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 Water-Resources 

Investigations Report 91-4139, 73 p.

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

assurance for laboratory analysis of suspendedsediment 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 streams 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,

and biological data (October 1992 through 

September 1993) and statistical summaries of 

water-quality 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 

extractants: Science of the Total Environment, 

v. 17, p. 167-196.

Porterfield, George, 1972, Computation of fluvialsediment discharge: U.S. Geological Survey 

Techniques of Water-Resources Investigations, 

book 3, chap. C3, 66 p.

Pritt, J.W., and Raese, J.W., eds.. 1995, Quality 

assurance/quality control manual National 

Water Quality Laboratory: U.S. Geological 

Survey Open-File Report 95-443, 35 p.

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

computation of streamflow: 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 

Open-File Report 94-304, 103 p.

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

collection and processing of surface-water and 

bed-material samples for physical and chemical 

analyses: U.S. Geological Survey Open-File 

Report 90-140, 71 p.

Wilde, F.D., Radtke, D.B., Gibs, Jacob, and Iwatsubo, 

R.T., 1998, National field manual for the 

collection of water-quality data: U.S. Geological 

Survey Techniques of Water-Resources 

Investigations, book 9, chap. A1-A9.

REFERENCES CITED 15
DATA

16 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through September 2001

[Abbreviations: ft3/s, cubic feet per second: °C, degrees Celsius; E, estimated: 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; , no data]

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

Date

OCT 2000

30...

JAN 2001

06...

MAR

28...

MAY

02...

22...

JUN

04..

JUL

23...

SEP

04...

Streamflow, pH, Specific Temper- Hardness, 

_,. instan- onsite conductance, ature. total 

taneous (standard onsite water (mg/L as 

(ft3/s) units) (|xS/cm) (°C) CaCO3)

1420 5.1 7.9 286 7.0 112

0830 3.6 7.7 315 2.0 120

0930 8.5 7.7 283 4.5 109

0750 15 7.8 232 3.0 89

0830 5.0 7.8 300 7.5 114

0730 9.2 7.7 243 5.5 98

1315 4.5 8.2 313 14.5 124

0915 1.9 7.7 364 10.5 146

Calcium, 

dissolved 

(mg/L)

32

34

31

26

32

28

35

42

Magnesium, 

dissolved

(mg/L)

7.7

8.4

7.6

6.0

8.0

6.9

8.7

10

Arsenic, 

dissolved

(Hg/L)

1.9

1.2

2.8

2.9

2.4

3.1

2.9

2.0

Date

OCT 2000

30...

JAN 2001

06...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

A Cadmium, Cadmium, Copper, 

total .. . ' total .. , , total 

. . dissolved .. dissolved .. recoverable . recoverable _ recoverable

(Hg/L) (W ' (Hg/L) (tlg/ ' (ng/L)

3 <0.14 <0.11 1.9 5.1

2 <.14 E.05 E.8 4.5

4 <.14 <.ll 4.5 7.4

4 <.14 <.ll 3.5 6.3

3 <.10 <.10 3.0 3.7

4 E.08 <.10 9.3 6.3

5 <.10 <.10 2.2 5.1

2 E.ll <.10 1.5 2.1

Iron, 

dissolved

(Hg/D

50

30

170

160

80

110

30

20

Iron, 

total 

recoverable

(Mg/L)

460

680

540

560

250

350

220

210

Lead, 

dissolved

ll^g/L)

<1

<1

<1

<1

<1

<1

<1

<1

Date

OCT 2000

30...

JAN 2001

06...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Lead, Manga- Manga- _. Zinc, 

, 6 nese, Zinc, . . total nese, ' .. , ' total 

.... total dissolved , , recoverable dissolved . . , n * recoverable 

, n^ n -. recoverable (Hg/L) , _ > (Mg/L) (Mg/L) . (Jig/L)

2 30 43 4 11

1 42 67 3 9

1 90 99 5 8

<1 35 50 3 4

<1 48 51 2 3

1 34 44 5 9

<1 20 24 2 5

<1 78 82 2 3

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

88

76

77

77

70

77

87

73

Sediment, 

suspended 

(mg/L)

9

14

10

10

4

8

3

3

Sediment 

discharge, 

suspended 

(ton/d)

0.12

.14

.23

.41

.05

.20

.04

.02

TABLE 4 17
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2000 through September 2001 (Continued) 

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

Date

OCX 2000

30...

JAN 2001

06...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Streamflow, pH, Specific Xemper- 

_,. instan- onsite conductance, ature, 

taneous (standard onsite water 

(ft3/s) units) (nS/cm) (°C)

1540 24 7.5 450 7.5

0915 13 7.5 567 1.0

1100 24 7.4 506 7.5

0830 30 7.6 409 4.5

0940 18 7.5 524 10.0

0845 36 7.4 385 5.5

1400 18 8.0 547 18.0

0945 14 7.5 573 15.5

Hardness, 

total 

(mg/L as 

CaC03)

134

173

156

134

158

123

177

177

Calcium, 

dissolved 

(mg/L)

39

48

44

39

45

35

51

50

Magnesium, 

dissolved

(mg/L)

9.2

13

11

9.1

11

8.6

12

13

Arsenic, 

dissolved

(|ig/L)

5.1

5.1

6.3

5.4

6.6

7.3

8.9

8.1

Date

OCX 2000

30...

JAN 2001

06...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Arsenic, , . Cadmium, 

... Cadmium, . . , Copper, total ,. . ' total .. T '

recoverable "f recoverable d'SSO'Vf 

(Hg/L) WV Oig/L) <W^>

12 .78 1.6 15

10 .71 1.3 6.3

8 1.0 1.2 24

8 .46 .66 12

8 .78 .86 16

10 .88 1.2 21

13 .62 .68 12

9 .57 .73 11

Copper, 

total 

recoverable

(H8/L)

66

37

37

23

25

51

21

23

Iron, 

dissolved

(Hg/L)

30

30

100

90

30

60

E10

20

Iron, 

total 

recoverable

(Hg/L)

1,480

940

460

570

270

630

120

120

Lead, 

dissolved

(Hg/L)

<1

<1

<1

<1

<1

<1

<1

<1

Date

OCX 2000

30...

JAN 2001

06...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Lead, Manga- Manga- 

. y nese, Zinc,

.. ,,. neS.e' ^ total dissolved recoverable dissolved . . .

<W<IO (MtfL) r )"'e ((Ig/L)

18 246 432 277

9 297 380 267

2 379 388 325

3 258 291 181

2 294 308 240

7 246 293 313

1 151 162 198

2 137 160 303

Zinc, 

total 

recoverable

(Hg/L)

419

334

376

191

235

366

209

334

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

90

81

82

90

83

84

87

77

Sediment, 

suspended

(mg/L)

48

26

10

13

8

24

3

8

Sediment 

discharge, 

suspended 

(ton/d)

3.1

.91

.65

1.1

.39

2.3

.15

.30

18 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through September 2001 (Continued)

12323600-SILVER BOW CREEK AT OPPORTUNITY, MONT.

Date

OCX 2000

30...

JAN 2001

04..

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Streamflow,

rr,. instan- Time 

taneous

(ft3/s)

1640 31

1715 36

1215 49

1015 67

1040 46

0950 74

1550 23

1110 13

pH, Specific Temper- Hardness, Calcium Magneonsite conductance, ature, total .. . 1 sium, 

(standard onsite water (nig/Las fS°n\ dissolved 

units) (|iS/cm) (°C) CaCO3) lme/L> (mg/L)

8.7

8.0

8.2

8.2

8.7

8.0

9.2

8.8

510 5.0 174

525 0.0 177

503 5.5 172

365 3.0 132

400 10.0 138

373 6.0 127

528 18.5 192

602 15.0 217

51 11

52 12

50 12

40 8.1

41 8.5

38 7.9

57 12

63 15

Arsenic, 

dissolved

8.4

8.9

10

9.7

9.7

9.3

15

16

Date

OCX 2000

30...

JAN 2001

04...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Af C' Cadmium, total .. . . 

. . dissolved recoverable . .. ,

(Hg/L) lkg/L)

15 .74

17 1.3

24 1.4

18 .44

14 .37

47 .67

28 .47

20 .32

Cadmium, 

total 

recoverable

(Hg/L)

1.3

1.8

2.5

1.3

.74

4.6

1.2

.84

Copper, C°Pf' 

"f recoverable

(Hg/L)

39 122

36 145

58 225

20 121

22 60

40 684

42 156

31 71

. Iron, 

Iron, ... 

,. , ' total dissolved . . 

_ recoverable

(Hg/L)

<10 550

<10 860

40 1,400

40 1,000

10 460

100 3,570

10 480

<IO 260

Lead, 

dissolved

(Hg/L)

<1

<1

<1

<1

<1

3

<1

<1

Date

OCX 2000

30..

JAN 2001

04...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Lead, Mangatotai nese, 

recoverable dissolved

(HB/L) (ng/L)

13 395

23 518

37 763

24 284

9 247

151 934

15 262

7 369

Manga- 7. Zinc, 

nese, Zinc,

total dissolved . , 

. . , . recoverable recoverable (Hg/L) , ,

(Hg/L) WV

477

621

861

420

311

1,520

341

400

202 403

406 538

362 662

178 323

94 192

397 1,180

41 245

58 161

Sediment, 

suspended Sediment, 

(percent suspended 

finer than (mg/L) 

0.062 mm)

82 12

80 17

86 31

82 28

82 14

86 125

70 8

75 7

Sediment 

discharge, 

suspended 

(ton/d)

1.0

1.7

4.1

5.1

1.7

25

.50

.25

TABLE 4 19
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2000 through September 2001 (Continued)

12323750-SILVER BOW CREEK AT WARM SPRINGS, MONT.

Date

OCT 2000

30...

JAN 2001

05...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Streamflow, pH, Specific Temper- Hardness, , . Magne-

_,. install- onsite conductance, ature, total .. ' ' slum, Time . . . _ dissolved ,. . , 

taneous (standard onsite water (mg/L as I n \ dissolved

(It3*) units) ((iS/cm) (°C) CaCO3) WW (mg/L)

1730 31

0740 39

1320 72

1115 87

1140 81

1100 114

1630 42

1145 21

8.4 683 6.0 277

8.1 783 2.0 314

8.8 598 7.0 239

8.4 511 8.0 204

8.7 456 13.5 168

8.4 448 9.0 181

9.2 531 19.0 220

9.1 647 16.5 283

78 20

90 21

69 16

60 13

48 12

50 14

62 16

81 20

Arsenic, 

dissolved

(H8/D

11

6.8

9.1

12

16

47

32

32

Date

OCT 2000

30...

JAN 2001

05..

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

^7' Cadmium,

total . 1 dissolved recoverable ,

(M8/L) (W!/L)

15 <.14

10 .16

12 <.14

18 <.14

19 <.10

52 <.10

41 <.10

34 <.10

Cadmium, Copper,

total ,. , . total 

. . dissolved .. recoverable _ ^ recoverable

(H8/L) ^ (Mg/L)

<.ll 1.9 3.4

.15 5.0 5.6

E.06 4.6 9.5

.14 2.8 11

E.09 4.8 8.0

.15 9.1 16

<.10 3.0 6.0

<.10 3.3 4.6

_ Iron, Iron, . . * j- . j total dissolved recoverable

^ (Hg/L)

<10 140

<10 180

<10 240

10 390

10 220

50 300

10 160

<10 80

Lead, 

dissolved

(Hg/L)

<1

<1

<1

<1

<1

<1

<1

<1

Date

OCT 2000

30...

JAN 2001

05...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Lead, Mangatotal nese, 

recoverable dissolved

(Hg/L) (Hg/L)

<1 310

<1 875

2 126

2 227

1 77

2 58

<1 62

<1 23

Manga- . Zinc, 

nese, Zinc, '

total dissolved . , 

.. , _ , recoverable 

recoverable (Ug/L) (,ip/n 

(Hg/L) ^W

327 11 10

899 26 27

215 9 24

329 7 25

141 4 13

145 9 24

159 2 7

55 1 4

Sediment, 

suspended Sediment, 

(percent suspended 

finer than (mg/L) 

0.062 mm)

82 3

80 2

80 8

86 10

80 8

84 13

47 5

67 3

Sediment 

discharge, 

suspended

(ton/d)

.25

.21

1.6

2.3

1.7

4.0

.57

.17

20 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through September 2001 (Continued)

12323770-WARM SPRINGS CREEK AT WARM SPRINGS, MONT.

Date

OCT 2000

31...

MAR 2001

28...

MAY

02

22...

JUN

04.,

SEP

04...

Streamflow, pH, Specific Temper- Hardness, 

.,,. install- onsite conductance, ature, total 

taneous (standard onsite water (mg/L as 

(ft3/s) units) (nS/cm) (°C) CaCO3)

0735 45 8.2 341 4.5 163

1305 33 8.6 384 5.0 187

1050 40 8.4 318 4.5 154

1115 56 8.4 246 10.0 110

1045 57 8.3 228 5.5 108

1210 14 8.4 349 14.0 167

Calcium, 

dissolved

49

57

47

33

33

51

Magnesium, 

dissolved 

(mg/L)

9.7

11

9.1

6.5

6.4

9.4

Arsenic, 

dissolved

3.9

4.6

4.3

4.4

3.8

5.4

Date

OCT 2000

31...

MAR 2001

28...

MAY

02

22...

JUN

04..

SEP

04...

Arsenic, ~ , . Cadmium, Copper, 

... Cadmium, ^ . . Copper, . "T.

tota' dissolved t0ta' dissolved tOta' . recoverable . ,, . recoverable . ... recoverable

(Hg/L) * (Hg/L) ^" (Hg/L)

5 <.14 <.ll 1.6 5.0

5 <.14 <.ll 2.1 5.7

5 <.14 <.ll 2.2 6.4

5 <.10 <.10 3.4 8.3

5 <.10 <.10 5.6 10

6 <.10 <.10 3.1 6.2

Iron, 

dissolved

<10

10

<10

<10

20

<10

Iron, 

total 

recoverable

(Hg/L)

60

60

80

110

120

40

Lead, 

dissolved

(Hg/L)

<1

<1

<]

<1

<1

<1

Date

OCT 2000

31...

MAR 2001

28...

MAY

02

22...

JUN

04...

SEP

04...

Lead, Manga- *"" . Zinc,

total nese, "f6; ,. .^ , total 

.... total dissolved . . recoverable dissolved . . , , recoverable

(ng/L) (ng/L) (|ag/L) e "W (ngA.)

<1 202 229 2 4

<1 214 237 2 2

<1 127 183 2 2

<1 48 110 1 3

<1 68 130 2 4

<1 29 57 <1 1

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

74

79

80

71

65

67

Sediment, 

suspended

(mg/L)

3

4

11

7

6

3

Sediment 

discharge, 

suspended 

(ton/A)

.36

.36

1.2

1.1

.92

.11

TABLE 4 21
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2000 through September 2001 (Continued)

12323800-CLARK FORK NEAR GALEN, MONT.

Date

OCX 2000

31...

JAN 2001

04...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Streamflow, pH, Specific Temper- 

,. . instan- onsite conductance, ature, 

lm taneous (standard onsite water 

(ft3/s) units) (nS/cm) (°C>

0815 80 8.1 498 5.0

1750 71 8.5 607 2.5

1430 115 8.6 542 7.5

1320 129 8.4 457 7.0

1230 133 8.6 379 13.0

1155 170 8.4 383 9.0

1740 82 8.9 411 18.0

1330 33 8.6 536 17.5

Hardness, 

total 

(mg/L as 

CaC03)

210

250

220

190

150

160

180

230

Calcium, 

dissolved 

fmg/L)

62

74

66

58

43

45

52

68

Magnesium, 

dissolved 

(mg/L)

14

17

14

12

10

11

12

15

Arsenic, 

dissolved

6.2

5.7

7.5

9.6

12

30

18

18

Date

OCX 2000

30...

JAN 2001

04...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Arsenic, , . Cadmium, fntal Cadmium, Copper, 

total . , dissolved total . , dissolved recoverable , - . recoverable , ,

(Hg/L) (tL&L'> (ng/L) (M8/LJ

8.2 <.14 <.ll 2.4

9.1 .19 E.08 4.0

10 <.14 E.08 4.3

14 <.14 E.10 3.3

14 <.10 E.07 4.7

35 E.08 E.11 7.6

23 <.10 <.10 5.5

20 <.10 <10 4.2

Copper, 

total 

recoverable

(M8/L)

5.8

8.0

12

12

9.7

17

8.4

6.0

Iron, 

dissolved

E7.1

<10

<10

E9.6

E9.7

33

E8.2

<10

Iron, 

total 

recoverable

(Hg/L)

100

150

240

300

196

260

139

56

Lead, 

dissolved 

(H8/L)

<1

<1

<1

<1

<1

1

<1

<1

Date

OCX 2000

30...

JAN 2001

04...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

i j »» Manga- Lead, Manga- . 

, nese, Zinc,

H a- ?"., total dissolved reco ,b,e d-Jgd rec___b,£ ^

<1 154 193 6

<1 460 522 12

2 138 240 7

2 157 258 6

1 54 128 3

2 54 162 6

<1 41 145 2

<1 25 47 2

Zinc, 

total 

recoverable

(Hg/L)

9

16

20

18

10

18

7

4

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

79

80

74

76

76

80

69

67

Sediment, 

suspended 

(mg/L)

2

4

9

9

8

11

4

3

Sediment 

discharge, 

suspended 

(ton/d)

.43

.77

2.8

3.1

2.9

5.0

.89

.27

22 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through September 2001 (Continued)

12324200-CLARK FORK AT DEER LODGE, MONT.

Date

OCX 2000

31...

JAN 2001

05...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Streamflow, pH, Specific Temper- Hardness, . Magne-

_. instan- onsite conductance. ature, total j.aCV J sium, Time . . , , . . , dissolved .. . ' 

taneous (standard onsite water (mg/L as . . dissolved

(ft3/s) units) (uS/cm) (°C) CaCO3) miB/L) (mg/L)

0910 194 8.2 585 5.5 252 73 17

0845 186 8.3 533 .5 227 67 15

1535 225 8.3 580 8.5 248 73 16

1410 217 8.6 497 10.0 218 64 14

1325 113 8.6 445 15.0 182 53 12

1255 291 8.2 488 8.5 197 57 13

1820 119 8.6 493 19.0 218 64 14

1410 43 8.6 553 17.5 224 66 14

Arsenic, 

dissolved

(UB/L)

8.3

6.0

11

11

12

16

17

11

Date

OCX 2000

31...

JAN 2001

05...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

Arsenic, , . Cadmium, Copper, . Iron, 

. . , Cadmium, . . , Copper, . \r. Iron, . , total . ' total , ' total ' total

recoverable d'sso' d recoverable d'SSO'vf recoverable d'SS°' recoverable

(UB/L) (UB/L) Own-) (UB/L) own-) (UB/L) Own.)

12 <.14 E.07 4.4 21 <IO 270

9 E.11 .18 4.1 23 <IO 390

19 <.14 .22 7.5 62 <10 800

15 <.14 .17 5.6 27 <10 390

14 <.10 E.06 7.8 18 <10 200

31 E.13 .50 19 119 40 1,310

22 <-10 E.10 8.7 28 <IO 330

12 <.10 <.10 6.0 8.2 <10 30

Lead, 

dissolved

(UB/L)

<1

<1

<1

<1

<1

<1

<1

<1

Date

OCX 2000

31...

JAN 2001

05...

MAR

28...

MAY

02...

22...

JUN

04...

JUL

23...

SEP

04...

- , ,. Manga- . Sediment, Lead, Manga- . Zinc, , , .. 

. . , nese, Zinc, ... suspended Sediment, total nese, , .. . . total , ^ . . 

, . . ' total dissolved . . (percent suspended recoverable dissolved .. , , recoverable ^, . . 

 . , recoverable (UB/L) /., /! \ finer than (mg/L) 

(UB/L) (UB/L) (jjg/L) (UB/L) 0.062mm)

2 34 98 10 27 80 15

3 60 156 14 34 79 16

7 48 185 10 53 72 43

3 40 111 5 24 73 18

2 55 87 5 14 78 10

16 82 410 12 109 67 110

3 24 132 4 24 80 6

<1 5.7 12 1 4 54 6

Sediment 

discharge, 

suspended 

(ton/d)

7.9

8.0

26

11

3.1

86

1.9

.70

TABLE 4 23
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2000 through September 2001 (Continued)

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON, MONT.

Streamflow, pH, Specific Temper- Hardness,

n . _. instan- onsite conductance, ature, total Date Time . , . . , .. . taneous (standard onsite water (mg/L as

(ft3/s) units) (|iS/cm) (°C) CaCO3)

NOV 2000

01... 1010 58 8.3 291 4.5 140

MAR 2001

21... 0910 128 8.0 253 0.0 100

MAY

03... 0730 383 8.0 174 2.5 79

22... 1430 319 8.2 188 13.0 83

JUN

05... 1015 455 8.1 268 7.5 120

SEP

04... 1515 19 8.4 326 19.5 140

Calcium, 

dissolved 

(mg/L)

40

30

23

24

34

41

Magnesium, 

dissolved 

(mg/L)

8.8

6.8

5.3

5.8

8.3

9.5

Arsenic, 

dissolved

(Mg/L)

4

6

4

4

6

5

*"?* Cadmium, Cadmium, Copper,

Date tota' , dissolved t0ta' , dissolved tota' , recoverable , . recoverable . . recoverable

(Mg/L) (W!/L) (Mg/L) (W!/L) (Mg/L)

NOV 2000

01... 5 <.14 <.ll <1.3 1.8

MAR 2001

21... 8 <.14 <.ll 2.6 4.2

MAY

03... 6 <14 <.ll 1.4 3.0

22... 5 <.10 <.10 1.7 1.8

JUN

05... 7 <.10 E.05 3.9 2.7

SEP

04... 6 <10 <.10 <1.0 1.3

Iron, 

dissolved

(Mg/U

<10

120

78

26

38

E6

Iron, 

total 

recoverable

51

690

700

269

430

42

Lead, 

dissolved

<1

<1

<1

<1

E.7

<1

Lead, Manga- Manga- ,. Zinc, 

... e nese, Zinc, ' 

n i total nese, . . ,. . . total Date . . . ' total dissolved . . recoverable dissolved . ._ . recoverable

(Mg/L) (Mg/L) ^ e ^ (ng^)

NOV 2000

01... <1 4.8 11 <1 <1

MAR 2001

21... 1 45 90 3 8

MAY

03... 2 7.9 48 2 6

22... <1 10 24 1 3

JUN

05... 1 14 47 1 6

SEP

04... <1 6.6 13 <1 <1

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

85

67

75

72

54

81

Sediment, 

suspended 

(mg/L)

2

39

33

13

47

3

Sediment 

discharge, 

suspended 

(ton/d)

.31

13

34

11

58

.15

24 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through September 2001 (Continued)

12324680-CLARK FORK AT GOLDCREEK, MONT.

Date

OCX 2000

31...

JAN 2001

05...

MAR

20...

MAY

02...

22...

JUN

04...

JUL

24...

SEP

04..

Streamflow, pH, Specific Temper- Hardness, . .

T. instan- onsite conductance, ature, total j.aCl.Um,' Time , . , , .. ' ' _ dissolved 

taneous (standard onsite water (mg/L as t i\\ 

(ft3/s) units) ((iS/cm) (°C) CaCO3) ( B"J

1015 322

1030 330

1250 483

1615 675

1520 513

1415 895

0720 303

1630 115

8.5 498 6.0 210 63

8.3 485 0.0 210 62

8.5 432 7.0 180 53

8.5 314 7.5 140 40

8.7 274 14.0 120 34

8.3 353 8.5 160 46

8.3 435 14.5 200 58

8.7 469 20.0 200 57

Magnesium, 

dissolved 

(mg/L)

14

13

12

8.9

7.7

9.9

13

13

Arsenic, 

dissolved

(Hg/U

7.2

5.8

11

6.8

6.4

9.1

11

10

Date

OCX 2000

31...

JAN 2001

05...

MAR

20...

MAY

02...

22...

JUN

04..

JUL

24...

SEP

04...

Arsenic, , . 

, Cadmium,

t0tal h. dissolved recoverable , ,

(Hg/L) (tig/L)

10 <.14

8 E.08

20 <.14

10 <.14

7 <.10

14 <.10

15 <.10

10 <.10

Cadmium, ,, Copper, ,

totai Ir-PP61-, total 'r°n' 

. , dissolved . , dissolved recoverable , . recoverable , .

(ng/u (tig/L) own.) ^

E.10 2.8 22 <10

E.09 3.0 12 <10

.46 13 95 50

.19 3.7 21 50

<.10 3.9 8.1 10

.41 5.6 55 20

E.07 4.3 12 <10

<.10 4.1 5.2 <10

Iron, 

total 

recoverable

(Hg/L)

320

180

2,030

860

220

870

250

30

Lead, 

dissolved

(Mg/L)

<1

<1

<1

<1

<1

<1

<1

<1

Date

OCX 2000

31...

JAN 2001

05...

MAR

20...

MAY

02...

22...

JUN

04...

JUL

24...

SEP

04...

Lead, Mangatotal nese, 

recoverable dissolved

ftig/L) (ng/L)

3 18

1 21

13 57

4 14

1 13

8 48

1 32

<1 4.0

Manga- Sediment, 

nese, Zinc, .' suspended

total dissolved . . (percent 

. . , , recoverable _ r .. recoverable (Mg/L) , .. . nner than

(Hg/L) W ' 0.062 mm)

106 4 29 85

63 11 22 79

312 11 114 64

108 3 26 58

38 1 9 80

285 5 61 91

73 3 14 88

10 <1 2 48

Sediment, 

suspended

(mg/L)

19

9

118

60

12

64

13

5

Sediment 

discharge, 

suspended

(ton/d)

17

8.0

154

109

17

155

11

1.6

TABLE 4 25
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2000 through September 2001 (Continued)

12331500-FLINT CREEK NEAR DRUMMOND, MONT.

Date

NOV 2000

01...

MAR 2001

20-

MAY

03...

22...

JUN

04...

JUL

24...

SEP

04...

Streamflow, pH, Specific Temper- 

 . instan- onsite conductance, ature, 

taneous (standard onsite water 

(ft3/s) units) mS/cm) (°C)

0910 114 8.4 357 4.5

1820 226 8.1 294 4.0

0840 76 8.4 278 3.0

1615 19 8.8 338 19.5

1520 331 8.3 333 10.0

0820 76 8.3 456 12.0

1710 5.4 8.5 527 19.0

Hardness, 

total 

(mg/L as 

CaCO3)

161

115

127

157

148

213

238

Calcium, 

dissolved

(rng/L)

44

30

34

43

39

58

64

Magnesium, 

dissolved 

(mg/L)

13

9.6

9.8

12

12

16

19

Arsenic, 

dissolved

U^g/L)

6.1

12

6.5

11

12

9.1

11

Date

NOV 2000

01...

MAR 2001

20...

MAY

03...

22...

JUN

04...

JUL

24...

SEP

04...

A n'C' Cadmium, Cadmium, 

total .. . . total .. f , 

., dissolved .. dissolved recoverable , ._ . recoverable ._ .

(M8/L) (Mg/L)

8 <.14 <.ll <1.3

22 <.14 .15 3.1

11 <.14 E.05 E.9

11 <.10 < 10 El.l

35 <.10 .30 2.1

13 <.10 <.10 1.4

12 <.10 <.10 El.l

recoverable

(Ug/L)

1.5

11

3.1

1.8

11

2.3

1.6

Iron, 

dissolved

(Ug/L)

<10

110

50

<10

40

20

<10

Iron, 

total 

recoverable

150

2,050

470

190

1,330

300

60

Lead, 

dissolved

(Hg/L)

<1

E.6

<1

<1

E.5

<1

<1

Date

NOV 2000

01...

MAR 2001

20...

MAY

03...

22...

JUN

04...

JUL

24...

SEP

04...

Lead, Manga- Ma"Batotal nese, f; /mc' 

. . ,. . . total dissolved recoverable dissolved . . . 

. . recoverable (Hg/L)

2 25 61 1

17 128 376 7

6 46 139 2

1 40 75 <1

34 139 595 3

3 56 125 1

<1 60 79 1

Zinc, 

total 

recoverable

7

53

15

5

87

10

2

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

84

77

92

94

69

89

30

Sediment, 

suspended

(mg/L)

8

155

26

10

195

19

27

Sediment 

discharge, 

suspended 

(ton/d)

2.5

95

5.3

.51

174

3.9

.39

26 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through September 2001 (Continued)

12331800-CLARK FORK NEAR DRUMMOND, MONT.

Date

OCT 2000

31...

JAN 2001

05...

MAR

20...

MAY

03...

23...

JUN

04...

JUL

24...

SEP

04...

Streamflow, pH, Specific Temper- Hardness, 

instan- onsite conductance, ature, total .. ' 

taneous (standard onsite water (mg/Las dissolved 

(ft3/s) units) (nS/cm) (°C) CaCO3) lmpu

1130 516 8.4 506 7.5 221 63

1130 432 8.3 504 2.0 221 64

1415 985 8.1 397 5.5 166 48

1040 835 8.3 356 7.0 158 46

0745 593 8.2 366 14.0 157 45

1630 1,510 8.3 400 8.5 177 51

0940 529 8.4 510 17.0 234 67

1745 157 8.5 601 19.5 266 72

Magnesium, 

dissolved 

(mg/L)

15

15

11

10

11

12

16

21

Arsenic, 

dissolved

7.2

6.6

11

7.7

8.3

9.9

12

9.4

Date

OCT 2000

31...

JAN 2001

05...

MAR

20...

MAY

03...

23...

JUN

04...

JUL

24...

SEP

04...

Arsenic, .-, . . Cadmium, _, Copper, _ 

... Cadmium, ... Copper, *T Iron, total .. , ' total .. , ' total .. , , 

., dissolved ., dissolved .. dissolved recoverable . recoverable , , recoverable , ,

(llg/L) (ug/L) (Ug/L) (Ug/L) (ug/L) (ug/L)

9 <.14 E.07 2.2 12 <10

8 E.07 E.07 2.8 7.0 <10

32 <.14 1.4 13 185 60

13 <.14 .21 4.1 36 20

10 <.10 E.09 5.2 15 <10

16 <.10 .28 7.0 41 20

15 <.10 E.09 3.4 16 <10

10 <.10 <.10 3.4 4.6 <10

Iron, 

total 

recoverable

(Ug/L)

240

130

4,490

1,000

290

790

340

20

Lead, 

dissolved

}

<1

<1

<1

<1

<1

E.5

<1

<1

Date

OCT 2000

31...

JAN 2001

05...

MAR

20...

MAY

03...

23...

JUN

04...

JUL

24...

SEP

04...

_ . _ , Manea- ~. Sediment, Lead, Manga- * . Zinc, . I ' 6 nese, Zinc, . . suspended total nese, . ' . ' total . f 

.. .. . , total dissolved . . (percent recoverable dissolved . , , . recoverable ... .. 

. . . , recoverable (Ug/L) . , finer than (jig/L) (UB/L) , _ (|ig/L) nn,- , ^ig/i^) u.uoz mm^

2 9.7 68 5 21 89

1 8.7 32 9 17 80

31 55 691 13 270 75

6 11 143 4 47 74

2 11 53 5 19 87

8 61 225 6 63 90

3 23 98 4 23 76

<1 4.5 8 1 3 65

Sediment, 

suspended 

(mg/L)

14

7

300

61

15

70

24

4

Sediment 

discharge, 

suspended 

(ton/d)

20

8.2

798

138

24

285

34

1.7

TABLE 4 27
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2000 through September 2001 (Continued)

12334510-ROCK CREEK NEAR CLINTON, MONT.

Date

NOV 2000

01...

MAR 2001

29...

MAY

03..

23...

JUN

05...

SEP

05...

Streamflow, pH, Specific Temper- Hardness, ,, . Magne- 

... instan- onsite conductance, ature, total ' sium, 

taneous (standard onsite water (mg/L as Dissolved ajssoived 

(ft3/s) units) (nS/cm) (°C) CaCO3) in>8«J (mg/L)

0730 209 8.0 148 4.5 69 18 5.9

1225 209 8.3 139 6.0 60 16 5.3

1150 676 8.0 88 6.0 39 10 3.4

1545 1,000 8.2 85 14.5 37 9.7 3.2

1730 886 8.2 104 10.0 47 12 3.9

1250 149 8.6 152 16.0 67 17 5.9

Arsenic, 

dissolved

(Hg/L)

.5

.5

.6

.5

.5

.6

Date

NOV 2000

01...

MAR 2001

29...

MAY

03..

23...

JUN

05...

SEP

05...

Arsenic, .-, , . Cadmium, .-, Copper, . Iron, 

. . Cadmium, , Copper, , , Iron, ' total .. ' total .. , ' total .. , ' total 

. . dissolved . . dissolved . . dissolved . . recoverable , _ . recoverable , . recoverable , . recoverable

(Hg/L) '^ (ng/L) '^ (W!/L) (^ (^

<2 <.14 <.ll <1.3 <.6 <10 40

<2 <.14 <.ll <1.3 E.5 <10 60

<2 <.14 <.ll <1.3 .7 60 180

<2 <.10 <.10 E.8 1.8 20 120

<2 <.10 <.10 E1.3 1.7 30 90

<2 <.10 <.10 <1.0 E.4 <10 40

Lead, 

dissolved OI&/L)

<i

<i

<i

<i

<i

<i

Date

NOV 2000

01...

MAR 2001

29...

MAY

03..

23...

JUN

05...

SEP

05...

, . ,, Manea- ... Sediment, Lead, Manga- . Zinc, . ' ,. 

total nese, "^ J*? . total suspended Segment 

recoverable dissolved tOta' d'sso'vf recoverable _(pe nt suspended 

(Hg/L) (ngfl.) recoverable (ngfl.) ((ig/L) f^2 ^ ("lg^)

<1 .9 3 <1 <1 76 2

<1 .9 3 <1 1 74 3

<1 1.6 8 <1 <1 74 10

<1 1.6 7 <1 <1 70 9

<1 1.4 6 <1 <1 76 5

<1 1.8 5 <1 <1 84 5

Sediment 

discharge, 

suspended 

(ton/d)

1.1

1.7

18

24

12

2.0

28 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through September 2001 (Continued)

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

Date

OCT 2000

31...

JAN 2001

05...

MAR

20...

MAY

03...

23...

JUN

05...

JUL

24...

SEP

05...

Streamflow, pH, Specific Temper- Hardness, 

T. instan- onsite conductance, ature, total a '" ' 

taneous (standard onsite water (mg/L as oissoivea 

(ft3/s) units) (MS/cm) (°C) CaCOj) l"ig/L)

1250 837

1330 682

1615 1,480

1430 1,820

1320 1,810

1540 2.700

1050 1,010

1010 331

8.5 401 6.5 174

8.5 416 1.5 182

8.1 315 5.5 127

8.4 252 8.5 111

8.6 211 14.0 92

8.3 311 12.0 134

8.5 360 17.0 164

8.4 359 15.0 159

49

52

36

31

26

38

46

42

Magnesium, 

dissolved 

(mg/L)

12

13

9.0

7.8

6.8

9.6

12

13

Arsenic, 

dissolved

(Hg/L)

5.1

4.5

9.1

4.8

4.0

8.3

7.2

4.1

Date

OCT 2000

31..

JAN 2001

05..

MAR

20...

MAY

03...

23...

JUN

05...

JUL

24...

SEP

05...

Arsenic, _ , . 

. . , Cadmium, total , '

recoverable "*d 

(Mg/L) ^

7 <.14

6 <.14

28 <.14

8 <.I4

4 <.10

14 <.10

9 <.10

5 <.10

Cadmium, ,, Copper, 

total popper ^ 

. . dissolved . , recoverable , , recoverable

(Mg/L) <«^> (Mg/L)

<.ll 1.5 6.6

<.ll 1.5 5.0

1.0 7.4 117

.14 3.3 23

<.10 2.9 8.1

.34 4.6 46

E.07 2.9 12

<.10 2.0 3.6

Iron, 

dissolved

(Hg/L)

<10

<10

90

30

<10

20

<10

<10

Iron, 

total 

recoverable

(MB/L)

120

80

4,250

720

200

790

240

60

Lead, 

dissolved

<1

<1

<1

<1

<1

<1

<1

<1

Date

OCT 2000

31...

JAN 2001

05...

MAR

20...

MAY

03...

23...

JUN

05...

JUL

24...

SEP

05...

Lead, Mangatotal nese, 

recoverable dissolved

(Mg/L) (Mg/L)

<1 3.4

<1 5.5

30 30

4 9.0

1 5.9

8 15

2 7.9

<1 5.0

Manganese, Zinc, f ' 

total dissolved recoverable 

recoveraMe (Mg/L) ^

32 4 12

19 4 12

622 10 236

97 3 36

29 2 11

179 4 71

59 3 17

12 2 6

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

90

85

87

77

72

82

81

83

Sediment, 

suspended 

(mg/L)

7

7

302

44

13

73

16

6

Sediment 

discharge, 

suspended 

(ton/d)

16

13

1,210

216

64

532

44

5.4

TABLE 4 29
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2000 through September 2001 (Continued)

12340000-BLACKFOOT RIVER NEAR BONNER, MONT.

Date

OCT 2000

31...

MAR 2001

29...

MAY

04..

23...

JUN

05...

SEP

05...

Streamtlow, pH, Specific Temper- Hardness, 

instan- onsite conductance, ature, total 

lme taneous (standard onsite water (mg/L as 

(ft3/s) units) (US/cm) (°C) CaCO3)

1400 577 8.6 267 6.5 130

0915 750 8.4 253 4.5 119

0840 2,300 8.1 163 8.0 77

0940 2,590 8.4 168 12.0 83

1240 2,990 8.4 205 11.0 97

0900 450 8.4 273 12.5 133

Calcium, 

dissolved

33

31

20

21

25

32

sium, 

dissolved 

(mg/L)

12

10

6.6

7.3

8.6

13

Arsenic, 

dissolved

(Hg/L)

.9

1.4

.7

.7

1.0

1.3

Date

OCT 2000

31...

MAR 2001

29...

MAY

04..

23...

JUN

05...

SEP

05...

Arsenic, Cadmium> Cadmium, Copper,

total ,. . , total j- i j total 

. . dissolved . , dissolved . . recoverable , , recoverable , recoverable

(|j,g/L) (|J,(5/L) (|4.g/L)

El <.14 <.ll <1.3 E.4

E2 <.14 <.ll E.7 1.6

El <.14 <.ll <1.3 1.0

<2 <.10 E.06 El.O 1.0

El <.10 <.10 E1.3 1.9

El <.10 <.10 <1.0 .6

Iron, 

dissolved

(Hg/L)

<10

50

20

<10

10

<10

Iron, 

total 

recoverable

(Hg/L)

30

270

170

110

240

30

Lead, 

dissolved

(H£/L)

<1

<1

<1

<1

<1

<1

Date

OCT 2000

31...

MAR 2001

29...

MAY

04..

23...

JUN

05...

SEP

05...

Lead, Manga- *^T ^ Zinc, 

total nese ^^ total

recoverable dissolved . . , _ . recoverable 

, . f n \ recoverable (|lg/L) , , (Mg/L) ftig/L) ^ **> (^L)

<1 1.1 3 <1 <1

<1 4.2 22 1 2

<1 2.1 19 <1 <1

<1 1.6 13 <1 1

<1 2.1 28 <1 2

<1 1.2 3 <1 <1

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

79

89

84

85

92

80

Sediment, 

suspended

(mg/L)

2

15

12

9

19

4

Sediment 

discharge, 

suspended 

(ton/d)

3.1

30

75

63

153

49

30 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through September 2001 (Continued)

12340500-CLARK FORK ABOVE MISSOULA, MONT.

Date

OCT 2000

31..

JAN 2001

05...

MAR

29...

MAY

04..

23...

JUN

05...

JUL

24...

AUG

*17...

*21...

SEP

05...

Streamflow, pH, Specific Temper- Hardness, 

T. instan- onsite conductance, ature, total 

taneous (standard onsite water (mg/L as 

(ft3/s) units) (nS/cm) (°C) CaCO3)

1540 1,310 8.5 346 6.0 157

1545 1,080 8.5 351 0.5 158

1015 1,620 8.5 339 6.0 153

1015 3,810 8.2 205 8.5 93

1135 4,090 8.3 189 12.5 85

1400 5,410 8.3 240 10.0 111

1335 1,830 8.5 307 18.5 147

1310 950 8.6 290 21.0 138

1115 920 8.4 301 18.5 138

0745 772 8.3 305 13.0 138

Calcium, 

dissolved 

(mg/L)

43

43

42

25

23

30

39

36

36

35

Magnesium, 

dissolved 

(mg/L)

12

12

12

7.3

6.9

8.8

12

12

12

12

Arsenic, 

dissolved 

(Rg/L)

3.4

3.2

4.3

2.5

2.0

4.1

4.4

3.6

3.6

3.0

Date

OCT 2000

31...

JAN 2001

05...

MAR

29...

MAY

04...

23...

JUN

05...

JUL

24...

AUG

*17...

*21...

SEP

05...

Arsenic, ,, , . Cadmium, ,, Copper, 

total Cadmium, Copper 

.. dissolved .. dissolved ., recoverable . - recoverable ._ recoverable

(Hg/L) "* ' (Rg/L) " (Rg/L)

4 <.14 <.ll E1.2 3.6

4 E.07 E.07 1.7 3.4

6 <.14 <.ll 2.5 8.8

4 <.14 E.06 3.0 10

E2 <.10 E.05 1.8 5.1

6 <.10 .14 4.3 17

6 <.10 <.10 2.6 5.8

4 <.10 <.10 E1.3 3.4

4 E.12 E.06 1.6 4.6

3 <.10 <.10 E.9 2.7

Iron, 

dissolved

(Rg/L)

<10

<10

20

30

10

20

<10

<10

<10

<10

Iron, 

total 

recoverable 

<Rg/L)

60

40

230

300

160

330

110

70

130

70

Lead, 

dissolved 

(Rg/L)

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

Date

OCT 2000

31...

JAN 2001

05...

MAR

29...

MAY

04...

23...

JUN

05...

JUL

24...

AUG

*17...

*21...

SEP

05...

. j >< Manga- . Lead, Manga- . Zinc,

total nese. "j ,.Z' ' total 

. , ,. , , total dissolved _ . recoverable dissolved . , , . recoverable

(W!/L) (Rg/L) **££* <^> (Rg/L)

<1 10 16 2 6

<1 9.5 13 3 8

1 37 56 2 13

2 21 48 2 13

<1 17 31 2 7

3 13 74 3 26

<1 20 43 2 7

<1 - 28 <1 3

<1 - 38 1 6

<1 10 T <\ 4

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

96

96

94

93

88

97

92

-

88

Sediment, 

suspended 

(mg/L)

3

2

13

21

11

25

7

4

7

6

Sediment 

discharge, 

suspended 

(ton/d)

11

5.8

57

216

121

365

35

10

17

13

*Supplemental samples collected to better define changes in trace-element concentrations and transport during the lowering of Milltown Reservoir water levels.

TABLE 4 31
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 2000 through 

September 2001

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

Day

,

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/s)

143

164

152

150

145

174

173

168

162

162

160

189

217

217

200

188

181

179

177

176

187

185

186

180

183

180

180

179

180

198

196

5,511 

178 

217 

143

Suspended sediment

Mean 

concentration 

(mg/L)

October

23

24

18

18

21

23

23

22

21

20

19

24

31

30

28

25

20

18

14

14

14

14

14

13

13

13

12

13

13

14

14

19 

31 

12

Discharge 

(ton/d)

8.9

11

7.4

7.3

8.2

11

11

10

9.2

8.7

8.2

12

18

18

15

13

9.8

8.7

6.7

6.7

7.1

7.0

7.0

6.3

6.4

6.3

5.8

6.3

6.3

7.5

7.4

282.2 

9.1 

18 

5.8

Mean 

streamflow

(ft3/s)

191

189

186

196

199

196

192

189

e!80

e!70

el 80

184

el 80

el 60

e!70

185

194

192

e!90

el 85

el 85

el 80

el 75

192

192

el 90

e!85

el 70

e!70

e!90

-

5,537 

185 

199 

160

Suspended sediment

Mean 

concentration 

(mg/L)

2000

November

15

15

16

29

20

15

14

14

15

15

17

24

16

14

14

14

13

12

11

11

11

11

11

19

22

24

25

26

24

22

-

17 

29 

11

Discharge 

(ton/d)

7.7

7.7

8.0

15

11

7.9

7.3

7.1

7.3

6.9

8.3

12

7.8

6.0

6.4

7.0

6.8

6.2

5.6

5.5

5.5

5.3

5.2

9.8

11

12

12

12

11

11

-

252.3 

8.4 

15 

5.2

Mean 

streamflow 

(ft3/s)

el 85

e!80

e!90

el 85

e!95

e!95

e!95

e!90

el 80

el 50

elOO

e90

e!30

e!80

e!60

e!55

e!90

e!60

e!50

e!30

el 20

e!40

e!60

177

185

184

188

e!80

el 80

186

195

5.185 

167 

195

90

Suspended sediment

Mean 

concentration 

(mg/L)

December

21

18

16

13

11

10

10

9

9

9

9

10

18

20

20

20

21

21

21

21

21

21

21

21

20

16

14

15

15

15

15

16 

21 

9

Discharge 

(ton/d)

10

8.7

8.2

6.5

5.8

5.3

5.3

4.6

4.4

3.6

2.4

2.4

6.3

9.7

8.6

8.4

11

9.1

8.5

7.4

6.8

7.9

9.1

10

10

7.9

7.1

7.3

7.3

7.5

7.9

225.0 

7.3 

11 

2.4

32 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through 

September 2001 (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/s)

193

e!90

188

187

189

e!80

e!70

el 70

e!80

e!75

el 70

182

180

e!70

e!75

e!55

e!50

e!60

el 70

el 70

e!70

el 80

e!70

el 70

el 80

el 80

el 70

el 55

e!40

el 60

e!70

5,349

173

193

140

Suspended sediment

Mean 

concentration 

(mg/L)

January

15

16

16

16

16

16

13

10

9

11

14

17

22

30

38

32

23

16

12

16

23

32

36

33

30

29

29

29

29

30

30

_

22

38

9

Discharge 

(ton/d)

7.8

8.2

8.1

8.1

8.2

7.8

6.0

4.6

4.4

5.2

6.4

8.4

11

14

18

13

9.3

6.9

5.5

7.3

11

16

17

15

15

14

13

12

11

13

14

319.2

10

18

4.4

Mean 

streamflow 

(ft3/s)

177

182

185

e!70

el 80

e!80

e!65

el 50

e!60

e!80

el 70

el 65

el 55

e!40

el45

e!50

el 60

e!70

el 65

e!70

el 85

e!80

e!75

el 70

e!60

el 65

el 55

el 55

-

-

-

4,664

167

185

140

Suspended sediment

Mean 

concentration 

(mg/L)

2001

February

30

31

36

42

48

44

40

35

33

33

34

34

35

35

37

42

50

56

58

61

63

65

62

57

52

57

45

45

..

-

-

_

45

65

30

Discharge 

(ton/d)

14

15

18

19

23

21

18

14

14

16

16

15

15

13

14

17

22

26

26

28

31

32

29

26

22

25

19

19

-

-

-

567

20

32

13

Mean 

streamflow 

(ft'/s)

e!65

182

170

170

179

191

205

206

207

197

197

190

200

208

197

198

196

193

215

229

208

201

194

197

206

254

244

236

228

221

213

6,297

203

254

165

Suspended sediment

Mean 

concentration 

(mg/L)

March

53

52

49

50

48

42

55

61

44

32

35

37

39

40

37

39

50

60

56

49

39

38

38

36

43

69

52

45

41

38

40

__

45

69

32

Discharge 

(ton/d)

24

26

22

23

23

22

30

34

25

17

19

19

21

22

20

21

26

31

33

30

22

21

20

19

24

47

34

29

25

23

23

775

25

47

17

TABLE 5 33
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 2000 through 

September 2001 (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/*)

210

209

214

209

199

194

192

194

196

188

181

183

192

186

182

178

179

178

182

186

186

185

184

181

177

176

181

189

206

213

-

5,710

190

214

176

Suspended sediment

Mean 

concentration

<mg/L)

April

39

29

35

33

33

36

31

29

29

30

35

33

30

32

31

27

26

25

22

26

42

33

22

24

29

21

20

20

22

22

-

._

29

42

20

Discharge 

(ton/d)

22

16

20

19

18

19

16

15

15

15

17

16

16

16

15

13

13

12

11

13

21

16

11

12

14

10

9.8

10

12

13

-

445.8

15

22

9.8

Mean 

streamflow

(ft'/s)

216

220

212

205

194

183

181

178

173

164

153

143

150

168

200

219

203

170

156

142

131

114

105

102

120

167

192

200

191

162

125

5,239

169

220

102

Suspended sediment

Mean 

concentration 

tmg/L)

2001

May

22

21

14

18

18

15

12

11

10

9

6

9

15

16

24

38

23

14

14

10

11

11

6

8

16

26

35

36

34

21

10

..

17

38

6

Discharge 

(ton/d)

13

12

8.0

10

9.4

7.4

5.9

5.3

4.7

4.0

2.5

3.5

6.1

7.3

13

22

13

6.4

5.9

3.8

3.9

3.4

1.7

2.2

5.2

12

18

19

18

9.2

3.4

259.2

8.4

22

1.7

Mean 

streamflow

(ft'/s)

102

92

117

279

265

220

204

182

176

192

200

194

253

269

235

207

184

166

161

139

117

117

99

96

87

76

71

82

92

78

-

4,752

158

279

71

Suspended sediment

Mean 

concentration

(mg/L)

June

9

9

18

86

54

25

17

12

11

14

12

9

38

38

23

12

8

9

10

8

6

4

5

10

15

16

9

8

11

7

-

..

17

86

4

Discharge 

(ton/d)

2.5

2.2

5.7

65

39

15

9.4

5.9

5.2

7.3

6.5

4.7

26

28

15

6.7

4.0

4.0

4.3

3.0

1.9

1.3

1.3

2.6

3.5

3.3

1.7

1.8

2.7

1.5

-

281.0

9.4

65

1.3

34 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through 

September 2001 (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/s)

193

e!90

188

187

189

el 80

e!70

e!70

e!80

el 75

e!70

182

180

e!70

e!75

e!55

el 50

el 60

e!70

e!70

el 70

el 80

e!70

e!70

el 80

e!80

e!70

el 55

el 40

el 60

e!70

5,349

173

193

140

Suspended sediment

Mean 

concentration 

(mg/L)

January

15

16

16

16

16

16

13

10

9

11

14

17

22

30

38

32

23

16

12

16

23

32

36

33

30

29

29

29

29

30

30

__

22

38

9

Discharge 

(ton/d)

7.8

8.2

8.1

8.1

8.2

7.8

6.0

4.6

4.4

5.2

6.4

8.4

11

14

18

13

9.3

6.9

5.5

7.3

II

16

17

15

15

14

13

12

11

13

14

319.2

10

18

4.4

Mean 

streamflow 

(ft3/s)

177

182

185

e!70

e!80

e!80

el 65

e!50

e!60

e!80

e!70

el 65

el 55

e!40

e!45

el 50

e!60

el 70

e!65

e!70

el 85

e!80

e!75

e!70

e!60

e!65

el 55

e!55

-

-

-

4,664

167

185

140

Suspended sediment

Mean 

concentration 

(mg/L)

2001

February

30

31

36

42

48

44

40

35

33

33

34

34

35

35

37

42

50

56

58

61

63

65

62

57

52

57

45

45

_

-

-

__

45

65

30

Discharge 

(ton/d)

14

15

18

19

23

21

18

14

14

16

16

15

15

13

14

17

22

26

26

28

31

32

29

26

22

25

19

19

-

-

567

20

32

13

Mean 

streamflow 

(ft3/s)

e!65

182

170

170

179

191

205

206

207

197

197

190

200

208

197

198

196

193

215

229

208

201

194

197

206

254

244

236

228

221

213

6,297

203

254

165

Suspended sediment

Mean 

concentration 

(mg/L)

March

53

52

49

50

48

42

55

61

44

32

35

37

39

40

37

39

50

60

56

49

39

38

38

36

43

69

52

45

41

38

40

__

45

69

32

Discharge 

(ton/d)

24

26

22

23

23

22

30

34

25

17

19

19

21

22

20

21

26

31

33

30

22

21

20

19

24

47

34

29

25

23

23

775

25

47

17

TABLE 5 33
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 2000 through 

September 2001 (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/s)

210

209

214

209

199

194

192

194

196

188

181

183

192

186

182

178

179

178

182

186

186

185

184

181

177

176

181

189

206

213

-

5,710 

190 

214 

176

Suspended sediment

Mean 

concentration

(mg/L)

April

39

29

35

33

33

36

31

29

29

30

35

33

30

32

31

27

26

25

22

26

42

33

22

24

29

21

20

20

22

22

29 

42 

20

Discharge 

(ton/d)

22

16

20

19

18

19

16

15

15

15

17

16

16

16

15

13

13

12

11

13

21

16

11

12

14

10

9.8

10

12

13

-

445.8 

15 

22 

9.8

Mean 

streamflow

(ft'/s)

216

220

212

205

194

183

181

178

173

164

153

143

150

168

200

219

203

170

156

142

131

114

105

102

120

167

192

200

191

162

125

5,239 

169 

220 

102

Suspended sediment

Mean 

concentration 

(mg/L)

2001

May

22

21

14

18

18

15

12

11

10

9

6

9

15

16

24

38

23

14

14

10

11

11

6

8

16

26

35

36

34

21

10

17 

38 

6

Discharge 

(ton/d)

13

12

8.0

10

9.4

7.4

5.9

5.3

4.7

4.0

2.5

3.5

6.1

7.3

13

22

13

6.4

5.9

3.8

3.9

3.4

1.7

2.2

5.2

12

18

19

18

9.2

3.4

259.2 

8.4 

22 

1.7

Mean 

streamflow

(ft3/s)

102

92

117

279

265

220

204

182

176

192

200

194

253

269

235

207

184

166

161

139

117

117

99

96

87

76

71

82

92

78

-

4,752 

158 

279 

71

Suspended sediment

Mean 

concentration

(mg/L)

June

9

9

18

86

54

25

17

12

11

14

12

9

38

38

23

12

8

9

10

8

6

4

5

10

15

16

9

R

11

7

-

17 

86 

4

Discharge 

(ton/d)

2.5

2.2

5.7

65

39

15

9.4

5.9

5.2

7.3

6.5

4.7

26

28

15

6.7

4.0

4.0

4.3

3.0

1.9

1.3

1.3

2.6

3.5

3.3

1.7

1.8

2.7

1.5

-

281.0 

9.4 

65 

1.3

34 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 through 

September 2001 (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/s)

73

63

56

51

56

61

62

59

52

65

60

53

73

84

76

80

100

124

123

113

107

125

121

120

110

96

88

83

76

75

92

2,577

83.1

125

51

Suspended sediment

Mean 

concentration 

(mg/L)

July

9

13

15

14

12

10

8

6

5

6

9

14

17

18

18

19

19

19

18

16

13

9

6

6

5

5

5

5

5

5

4

__

11

19

4

Discharge 

(ton/d)

1.8

2.2

2.3

1.9

1.8

1.6

1.3

.96

.70

1.1

1.5

2.0

3.4

4.1

3.7

4.1

5.1

6.4

6.0

4.9

3.8

3.0

2.0

1.9

1.5

1.3

1.2

1.1

1.0

1.0

.99

75.65

2.4

6.4

.70

Mean 

streamflow 

(ft3/s)

79

73

62

55

60

52

43

38

35

35

32

32

33

31

32

38

42

38

37

38

37

37

33

33

32

34

35

40

45

47

46

1,304

42.1

79

31

Suspended sediment

Mean 

concentration 

(mg/L)

2001

August

5

19

35

30

21

16

15

14

15

17

22

28

32

34

36

35

31

27

24

23

24

26

29

31

26

21

19

20

24

22

17

__

24

36

5

Discharge 

(ton/d)

1.1

3.7

5.9

4.5

3.4

2.2

1.7

1.4

1.4

1.6

1.9

2.4

2.9

2.8

3.1

3.6

3.5

2.8

2.4

2.4

2.4

2.6

2.6

2.8

2.2

1.9

1.8

2.2

2.9

2.8

2.1

81.0

2.6

5.9

1.1

Mean 

streamflow

(ft3/s)

45

43

41

43

48

114

159

142

126

116

109

109

107

106

106

113

122

124

123

119

120

114

113

108

103

96

95

98

98

98

-

3,058

102

159

41

Suspended sediment

Mean 

concentration 

(mg/L)

September

12

9

9

9

9

16

21

18

14

11

9

8

8

8

7

7

6

4

4

4

5

5

5

6

8

9

9

9

9

9

-

__

9

21

4

Discharge 

(ton/d)

1.5

1.0

1.0

1.0

1.2

4.9

9.0

6.9

4.8

3.4

2.6

2.4

2.3

2.3

2.0

2.1

2.0

1.3

1.3

1.3

1.6

1.5

1.5

1.7

2.2

2.3

2.3

2.4

2.4

2.4

-

74.6

2.5

9.0

1.0

TOTAL FOR WATER YEAR 2001:

STREAMFLOW 55,183 ft3/s 

SEDIMENT DISCHARGE 3.637.95 tons

TABLE 5 35
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 2000 

through September 2001

[Abbreviations: ft3/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/s)

692

978

879

778

719

684

689

697

706

711

698

736

860

962

981

934

892

862

866

871

898

901

889

863

841

827

814

807

810

817

833

25495

822

981

684

Suspended sediment

Mean 

concentration

(mg/L)

October

28

56

27

15

12

11

11

11

11

11

11

13

22

27

27

23

18

17

15

13

12

11

10

9

8

8

8

8

8

7

7

 

15

56

7

Discharge 

(ton/d)

52

148

64

32

23

20

20

21

21

21

21

26

51

70

72

58

43

40

35

31

29

27

24

21

18

18

18

17

17

15

16

1,089

35

148

15

Mean 

streamflow

(ft3/s)

827

809

781

779

818

824

796

737

733

689

649

675

680

639

658

716

679

676

664

611

e550

e550

e550

e570

723

697

e650

e600

e580

e600

-

20.510

684

827

550

Suspended sediment

Mean 

concentration 

(mg/L)

2000

November

8

8

9

8

6

7

7

8

8

7

8

9

10

10

10

9

9

8

8

7

7

7

7

8

13

12

12

11

11

10

-

..

9

13

6

Discharge 

(ton/d)

18

17

19

17

13

16

15

16

16

13

14

16

18

17

18

17

16

15

14

12

10

10

10

12

25

23

21

18

17

16

-

479

16

25

10

Mean 

streamflow

(ft3/s)

e630

e580

e550

e530

e520

e500

e500

e520

e530

e500

e450

e380

e350

e380

e500

e500

e550

e600

e570

e530

e500

561

618

654

683

694

676

663

623

618

632

17,092

551

694

350

Suspended sediment

Mean 

concentration

(mg/L)

December

10

9

8

7

6

6

6

5

5

5

5

5

5

5

5

6

6

5

4

3

2

3

7

14

21

20

15

13

12

11

9

..

8

21

2

Discharge 

(ton/d)

17

14

12

10

8.4

8.1

8.1

7.0

7.2

6.8

6.1

5.1

4.7

5.1

6.8

8.1

8.9

8.1

6.2

4.3

2.7

4.5

12

25

39

37

27

23

20

18

15

385.2

12

39

2.7

36 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 

through September 2001 (Continued)

Day

,

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/s)

650

e630

601

624

676

690

e600

514

514

569

633

617

632

623

596

598

577

537

560

627

598

587

605

566

555

593

582

557

495

501

528

18,235

588

690

495

Suspended sediment

Mean 

concentration 

(mg/L)

January

8

8

8

8

8

8

7

6

6

6

7

7

8

8

8

8

9

9

10

11

12

11

10

8

8

8

10

11

22

13

11

__

9

22

6

Discharge 

(ton/d)

14

14

13

13

15

15

11

8.3

8.3

9.2

12

12

14

13

13

13

14

13

15

19

19

17

16

12

12

13

16

17

29

18

16

443.8

14

29

8.3

Mean 

streamflow

(ft'/s)

590

615

620

613

626

644

e630

562

518

525

559

577

569

e570

569

559

518

537

569

e580

581

616

620

625

609

574

e570

e550

-

-

-

16,295

582

644

518

Suspended sediment

Mean 

concentration 

<mg/L)

2001

February

12

12

12

14

16

14

10

6

4

4

5

6

6

7

9

11

12

13

14

14

16

15

13

11

11

11

10

11

-

-

-

__

11

16

4

Discharge

(ton/d)

19

20

20

23

27

24

17

9.1

5.6

5.7

7.5

9.3

9.2

11

14

17

17

19

22

22

25

25

22

19

18

17

15

16

-

--

475.4

17

27

5.6

Mean 

streamflow 

(ft3/s)

e550

e580

e650

e650

645

660

674

709

746

767

748

735

778

868

838

808

793

780

887

1,410

1,370

1,210

1,160

1.170

1,160

1,110

1,110

1,050

1,020

1,030

1,000

27,666

892

1,410

550

Suspended sediment

Mean 

concentration 

<mg/L)

March

22

20

16

10

9

10

12

14

19

21

19

17

26

41

34

29

24

27

52

283

134

70

54

55

54

39

34

36

32

31

23

41

283

9

Discharge 

(ton/d)

33

31

28

18

16

18

22

27

38

43

38

34

55

96

77

63

51

57

125

1110

496

229

169

174

169

117

102

102

88

86

62

3,774

122

1,110

16

TABLE 6 37
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 2000 

through September 2001 (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

(ft'/s)

958

958

955

913

896

868

864

883

877

857

837

824

813

802

786

764

784

824

911

Q61

955

909

881

891

935

1,070

1,290

1,590

1,880

2,020

-

29,756

992

2,020

764

Suspended sediment

Mean 

concentration 

(mg/L)

April

22

24

17

16

14

13

10

11

15

9

10

8

8

6

5

8

13

17

19

20

13

12

19

16

24

42

68

94

110

126

-

__

26

126

5

Discharge 

(ton/d)

57

62

44

39

34

30

23

26

36

21

23

18

18

13

11

17

28

38

47

52

34

29

45

38

61

121

237

404

558

687

-

2,851

95

687

11

Mean 

streamflow

(ft3/s)

2,100

2,110

1,850

1,670

1,600

1,590

1,520

1,480

1,550

1,650

1,680

1,690

1,870

2,250

2,630

3,320

3,150

2,710

2,410

2,240

2,080

1,910

1,840

1,850

1,880

1,990

2,140

2,160

2,120

1,940

1,750

62,730

2,024

3,320

1,480

Suspended sediment

Mean 

concentration 

(mg/L)

2001

May

98

84

54

41

35

27

24

19

22

28

26

26

33

82

92

113

86

53

33

27

22

19

16

17

16

20

26

23

23

17

14

_

39

113

14

Discharge 

(ton/d)

556

479

270

185

151

116

98

76

92

125

118

119

167

498

653

1,010

731

388

215

163

124

98

79

85

81

107

150

134

132

89

66

7,355

237

1,010

66

Mean 

streamflow

(ft'/s)

1,580

1,420

1,430

2,050

2,670

2,370

2,160

1,990

2,020

2,190

2,220

2,220

2,370

2,590

2,480

2,250

2,070

1,950

1,860

1,740

1,590

1,450

1,360

1,300

1,240

1,190

1,160

1,160

1,210

1,200

-

54,490

1,816

2,670

1,160

Suspended sediment

Mean 

concentration 

(mg/L)

June

11

10

12

34

71

45

30

22

22

25

28

26

31

40

39

31

26

22

20

19

17

14

12

10

8

6

6

7

6

5

-

..

22

71

5

Discharge 

(ton/d)

47

38

46

188

512

288

175

118

120

148

168

156

198

280

261

188

145

116

100

89

73

55

44

35

27

19

19

22

20

16

-

3,711

124

512

16

38 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 

through September 2001 (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/s)

1,140

1,130

1,050

946

919

923

907

869

847

803

787

782

811

863

935

1,020

1,020

1,040

1,070

1,060

1,010

1.000

1,040

975

925

870

823

780

738

749

979

28,811 

929

1,140

738

Suspended sediment

Mean 

concentration 

(mg/L)

July

4

4

4

4

4

4

4

4

5

5

6

7

7

8

10

12

13

13

13

14

14

16

17

17

17

16

16

16

16

16

24

11

24

4

Discharge 

(ton/d)

12

12

11

10

9.9

10

9.8

9.4

11

11

13

15

15

19

25

33

36

37

38

40

38

43

48

45

42

38

36

34

32

32

63

828.1 

27

63

9.4

Mean 

streamflow

(ft'/s)

1,170

1,010

886

825

822

793

737

687

648

622

598

564

543

513

496

481

464

447

434

421

408

387

374

358

348

342

337

329

328

326

322

17,020 

549

1,170

322

Suspended sediment

Mean 

concentration 

(mg/L)

2001

August

37

24

14

13

13

13

12

12

11

10

9

8

7

7

7

7

7

6

6

6

5

5

4

4

4

4

4

4

4

4

4

9

37

4

Discharge 

(ton/d)

117

65

33

29

29

28

24

22

19

17

15

12

10

9.7

9.4

9.1

8.8

7.2

7.0

6.8

5.5

5.2

4.0

3.9

3.8

3.7

3.6

3.6

3.5

3.5

3.5

521.8 

17

117

3.5

Mean 

streamflow

(ft'/s)

323

328

327

325

327

346

394

474

499

491

477

462

465

469

461

460

462

464

463

458

460

468

468

471

472

472

465

456

463

470

13,140 

438

499

323

Suspended sediment

Mean 

concentration 

(mg/L)

September

5

7

8

7

6

4

5

8

7

7

7

6

6

6

6

6

6

5

5

5

5

5

5

5

7

7

7

7

6

5

-

6

8

4

Discharge 

(ton/d)

4.4

6.2

7.1

6.1

5.3

3.7

5.3

10

9.4

9.3

9.0

7.5

7.5

7.6

7.5

7.5

7.5

6.3

6.3

6.2

6.2

6.3

6.3

6.4

8.9

8.9

8.8

8.6

7.5

6.3

-

213.9 

7.1

10

3.7

TOTAL FOR WATER YEAR 2001:

STREAMFLOW 331,240 ft3/s 

SEDIMENT DISCHARGE 22,127.2 tons

TABLE 6 39
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 2000 

through September 2001

[Abbreviations: ft3/s, cubic feet per second; e, estimated; mg/L, milligrams per liter; ton/d, tons per day. Symbol: , no data]

Day

j

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/s)

1,240

1,640

1,480

1,340

1,250

1,210

1,200

1,210

1,200

1,200

1,190

1,200

1,340

1,520

1,540

1,480

1,400

1,350

1,390

1,350

1,420

1,400

1,400

1,360

1,350

1,320

1,310

1,310

1,310

1,310

1,310

41,530

1,340

1,640

1,190

Suspended sediment

Mean 

concentration 

(mg/L)

October

6

9

6

5

5

5

4

4

4

4

4

5

7

8

7

6

6

6

6

6

9

7

6

5

4

4

4

5

5

4

3

__

5

9

3

Discharge 

(ton/d)

20

40

24

18

17

16

13

13

13

13

13

16

25

33

29

24

23

22

23

22

35

26

23

18

15

14

14

18

18

14

11

623

20

40

11

Mean 

streamflow 

(ft3/s)

1,300

1,290

1,250

1,250

1,310

1,320

1,270

1,240

1,210

1,140

1,100

1,130

1,170

1,040

1,100

1,160

el, 150

1,100

1,100

988

e940

e930

933

943

1,210

1,190

el, 150

1.100

el ,050

el, 100

--

34,164

1,139

1.320

930

Suspended sediment

Mean 

concentration 

(mg/L)

2000

November

5

5

5

6

6

6

5

5

4

4

4

4

4

4

5

5

5

5

5

5

4

4

4

4

4

4

4

4

4

4

-

__

5

6

4

Discharge 

(ton/d)

18

17

17

20

21

21

17

17

13

12

12

12

13

11

15

16

16

15

15

13

10

10

10

10

13

13

12

12

11

12

--

424

14

21

10

Mean 

streamflow 

(ftVs)

1,140

1,020

el, 000

e980

e970

e950

e950

e950

e980

el.OOO

e800

e650

e600

e700

e900

e900

el.OOO

el. 050

el .000

e950

e850

e900

el.OOO

el, 050

el.100

el, 100

el, 050

el, 050

el.OOO

el.OOO

el, 050

29,640

956

1,140

600

Suspended sediment

Mean 

concentration 

(mg/L)

December

4

5

5

6

6

6

5

4

3

2

2

2

2

2

3

3

3

3

3

2

2

2

2

4

9

8

7

6

5

4

3

__

4

9

2

Discharge 

(ton/d)

12

14

14

16

16

15

13

10

7.9

5.4

4.3

3.5

3.2

3.8

7.3

7.3

8.1

8.5

8.1

5.1

4.6

4.9

5.4

11

27

24

20

17

14

11

8.5

329.9

11

27

3.2

40 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 

through September 2001 (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 

(ft'/s)

el, 050

1,050

1,020

1,010

1,070

1,080

e950

e850

e850

e900

el, 000

el, 000

1,010

1,010

989

e950

e900

e900

e950

980

930

943

e930

e900

924

e950

e930

e900

e800

e850

879

29,455

950

1,080

800

Suspended sediment

Mean 

concentration 

<mg/L)

January

2

2

2

2

3

2

2

3

3

4

5

5

6

6

5

3

2

2

2

2

2

2

2

2

2

2

3

3

3

4

4

_

3

6

2

Discharge 

(ton/d)

5.7

5.7

5.5

5.5

8.7

5.8

5.1

6.9

6.9

9.7

14

14

16

16

13

7.7

4.9

4.9

5.1

5.3

5.0

5.1

5.0

4.9

5.0

5.1

7.5

7.3

6.5

9.2

9.5

236.5

7.6

16

4.9

Mean 

streamflow

(ft'/s)

978

964

962

934

959

983

956

884

e800

e850

920

e900

932

e900

847

837

e850

e870

e920

e920

935

959

972

976

961

930

905

843

-

-

--

25,647

916

983

800

Suspended sediment

Mean 

concentration 

(mg/L)

2001

February

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

3

3

3

3

3

3

3

4

6

-

-

-

_

4

6

3

Discharge 

(ton/d)

11

10

10

10

10

11

10

9.5

8.6

9.2

9.9

9.7

10

9.7

9.1

9.0

9.2

9.4

9.9

7.5

7.6

7.8

7.9

7.9

7.8

7.5

9.8

14

-

-

-

263.0

9.4

14

7.5

Mean 

streamflow

(ft'/s)

832

853

907

916

923

943

967

1,000

1,080

1,120

1,060

1,040

1,110

1,220

1,220

1,150

1,180

1,140

1,230

1,770

1,930

1,880

1,880

1,930

1,870

1,810

1,800

1,720

1,680

1.690

1,720

41,571

1,341

1,930

832

Suspended sediment

Mean 

concentration 

<mg/L)

March

4

4

4

3

4

3

4

5

5

6

4

4

7

8

8

9

8

7

9

26

26

17

15

14

14

14

13

12

11

11

10

_

9

26

3

Discharge 

(ton/d)

9.0

9.2

9.8

7.4

10

7.6

10

14

15

18

11

11

21

26

26

28

25

22

30

124

135

86

76

73

71

68

63

56

50

50

46

1,208.0

39

135

7.4

TABLE 7 41
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 2000 

through September 2001 (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 

(ft'/s)

1,660

1,590

1,680

1,550

1,510

1,460

1,460

1,510

1,520

1,480

1,440

1,440

1,390

1,380

1,390

1,330

1,380

1,480

1,610

1,730

1,790

1,710

1,680

1,730

1,780

2,130

2,720

3,390

4,210

4,580

-

55,710 

1.857 

4,580 

1,330

Suspended sediment

Mean 

concentration 

(mg/L)

April

14

11

10

11

9

9

10

7

6

%

7

5

5

7

7

8

9

8

8

10

15

7

7

11

8

11

12

15

31

24

-

10 

31 

5

Discharge 

(ton/d)

63

47

45

46

37

35

39

29

25

32

27

19

19

26

26

29

34

32

35

47

72

32

32

51

38

63

88

137

352

297

-

1,854 

62 

352 

19

Mean 

streamflow

(ft3/s)

4,660

4,640

4,210

3,800

3,740

3,770

3,660

3,600

3,710

4,040

4,160

4,220

4,700

5,660

6,370

6,780

6,520

5,750

5,280

4,810

4,590

4,290

4,200

4,420

4,760

5,130

5,400

5,500

5,390

4,990

4,490

147,240 

4,750 

6,780 

3,600

Suspended sediment

Mean 

concentration 

(mg/L)

2001

May

21

22

19

17

13

14

17

9

9

10

15

11

11

21

32

44

41

28

24

19

13

10

10

10

11

11

12

13

15

14

11

17

44 

9

Discharge 

(ton/d)

264

276

216

174

131

143

168

87

90

109

168

125

140

321

550

805

722

435

342

247

161

116

113

119

141

152

175

193

218

189

133

7,223 

233 

805 

87

Mean 

streamflow 

(ft3/s)

4,050

3,760

3,760

4,630

5,340

5,110

4,800

4,580

4,640

4,950

4,850

4,790

5,090

5.620

5,760

5,560

5,280

5,050

4,880

4,570

4,150

3,840

3,570

3,440

3,230

3,070

2,880

2860

2,860

2,710

129,680 

4,323 

5,760 

2,710

Suspended sediment

Mean 

concentration

(mg/L)

June

9

8

9

12

24

26

21

18

18

19

19

20

22

24

26

25

22

20

18

15

12

10

9

9

9

10

10

10

6

5

-

16 

26 

5

Discharge 

(ton/d)

98

81

91

150

346

359

272

223

226

254

249

259

302

364

404

375

314

273

237

185

134

104

87

84

78

83

78

77

46

37

--

5,870 

196 

404 

37

42 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2000 

through September 2001 (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/s)

2.530

2,410

2,300

2,140

2,080

2,020

1,980

1,940

1,860

1,800

1,720

1,740

1,680

1,750

1,780

1,820

1,900

1,960

2,000

1,900

1,880

1,810

1,800

1,760

1.640

1,610

1,510

1,450

1,390

1,400

1,670

57,230

1,846

2,530

1,390

Suspended sediment

Mean 

concentration 

(mg/L)

July

5

5

5

6

6

6

6

6

6

6

6

7

7

6

6

6

6

6

7

6

5

5

6

6

5

5

6

6

6

6

7

__

6

7

5

Discharge 

(ton/d)

34

33

31

35

34

33

32

31

30

29

28

33

32

28

29

29

31

32

38

31

25

24

29

29

22

22

24

23

23

23

32

909

29

38

22

Mean 

streamflow 

(ftVs)

1,970

1,860

1.690

1,570

1,490

1,470

1,380

1,260

1,260

1.190

1,190

1,140

1,080

1,090

1,020

1,050

989

988

1,020

983

932

904

869

850

823

813

757

735

696

684

676

34,429

1.111

1,970

676

Suspended sediment

Mean 

concentration

(mg/L)

2001

August

9

8

7

6

6

5

4

3

3

3

4

3

4

4

4

4

4

4

5

6

7

8

9

10

11

10

8

6

4

3

3

__

6

11

3

Discharge 

(ton/d)

48

40

32

25

24

20

15

10

10

9.6

13

9.2

12

12

11

11

11

11

14

16

18

20

21

23

24

22

16

12

7.5

5.5

5.5

528.3

17

48

5.5

Mean 

streamflow 

(ft'/s)

691

735

749

766

719

769

811

888

953

924

914

894

908

876

873

872

891

852

863

860

854

870

854

859

857

866

851

834

847

844

-

25,344

845

953

691

Suspended sediment

Mean 

concentration 

(mg/L)

September

3

3

3

4

5

4

4

3

3

3

3

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

-

__

4

5

3

Discharge 

(ton/d)

5.6

6.0

6.1

8.3

9.7

8.3

8.8

7.2

7.7

7.5

7.4

9.7

9.8

9.5

9.4

9.4

9.6

9.2

9.3

9.3

9.2

9.4

9.2

9.3

9.3

9.4

9.2

9.0

9.1

9.1

-

260.0

8.7

9.8

5.6

TOTAL FOR WATER YEAR 2001:

STREAMFLOW 651,640 ft3/s 

SEDIMENT DISCHARGE 19,728.7 tons

TABLE 7 43
Table 8. Chemical and suspended-sediment analyses of field replicates for water samples, upper Clark Fork basin, Montana

[Abbreviations: E, estimated; |ig/L, micrograms per liter; mg/L, milligrams per liter; mm, millimeter. Symbols: <, less than minimum 

reporting level; , no data]

Station 

number

12323230 

12323250 

12323770

12324200

12331800

12334550

12340500

Station name

Blacktail Creek at Harrison Avenue, at Butte 

Silver Bow Creek below Blacktail Creek, at Butte 

Warm Springs Creek at Warm Springs

Clark Fork at Deer Lodge

Clark Fork near Drummond

Clark Fork at Turah Bridge, near Bonner

Clark Fork above Missoula

Date Time

03-28-01 0930 

03-28-01 0935 

07-23-01 1400 

07-23-01 1405 

06-04-01 1045

06-04-01 1050

01-05-01 0845

01-05-01 0850

09-04-01 1745

09-04-01 1750

05-03-01 1430

05-03-01 1435

05-23-01 1135

05-23-01 1140

CaCO3)

109 

109 

177 

178 

108

-

227

231

266

267

111

112

85

87

! « M*

31 

31 

51 

51 

33

-

67

69

72

72

31

32

23

23

^nesium, Arsenic, 

ssolved dissolved

7.6 2.8 

7.6 2.9 

12 8.9 

12 9.1 

6.4 3.8

4.0

15 6.0

14 6.0

21 9.4

21 9.5

7.8 4.8

7.9 4.8

6.9 2.0

7.1 2.1

recoverable

(Mg/L)

4 

4 

13 

13 

5

5

9

9

10

10

8

8

E2

3

Station 

number

12323230

12323250

12323770

12324200

12331800

12334550

12340500

Date

03-28-01

03-28-01

07 23-01

07-23-01

06-04-01

06-04-01

01-05-01

01-05-01

09-04-01

09-04-01

05-03-01

05-03-01

05-23-01

05-23-01

Cadmium, 

dissolved

(Mg/L)

<0.14

<.14

.62

.63

<.10

<10

E.11

<.14

<.10

<.10

<.14

<.14

<.10

<.10

Cadmium, 

total 

recoverable

<0.11

<.ll

.68

.70

<.10

<.10

.18

.18

<.10

<10

.14

E.10

E.05

<.10

Copper, 

dissolved

(Mg/L)

4.5

4.2

12

13

5.6

2.9

4.1

4.1

3.4

3.6

3.3

3.0

1.8

2.0

Copper, 

total 

recoverable

(Mg/L)

7.4

7.4

21

20

10

9.3

23

23

4.6

4.5

23

24

5.1

7.0

Iron, 

dissolved

(Mg/L)

170

170

E10

E10

20

-

<10

<10

<10

<10

30

30

10

10

Iron, 

total 

recoverable

(Mg/L)

540

540

120

140

120

120

390

390

20

20

720

720

160

170

Lead, 

dissolved

(Mg/L)

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

Station 

number

12323230

12323250

12323770

12324200

12331800

12334550

12340500

Date

03-28-01

03-28-01

07-23-01

07-23-01

06-04-01

06-04-01

01-05-01

01-05-01

09-04-01

09-04-01

05-03-01

05-03-01

05-23-01

05-23-01

Lead, 

total 

recoverable

(Mg/L)

1

<1

1

1

<1

<1

3

3

<1

<1

4

4

<1

<1

Manganese, 

dissolved

(Mg/L)

90

92

151

156

68

69

60

60

4.5

4.5

9.0

9.1

17

17

Manganese, 

total 

recoverable

(Mg/L)

99

100

162

161

130

130

156

154

8

9

97

100

31

30

Zinc, 

dissolved

(Mg/D

5

5

198

203

2

2

14

14

1

1

3

3

2

1

Zinc, 

total 

recoverable

(Mg/L)

8

8

209

207

4

4

34

33

3

3

36

35

7

7

Sediment, 

suspended, 

diameter, 

percent Finer 

than 0.062 mm

77

-

87

83

65

81

79

79

65

-

77

78

88

90

Sediment, 

suspended 

(mg/L)

10

--

3

3

6

6

16

17

4

-

44

46

11

10

44 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
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, (J.g/L

Arsenic, dissolved, |j,g/L

Cadmium, total recoverable, ng/L

Cadmium, dissolved, |ig/L

Copper, total recoverable, |j,g/L

Copper, dissolved, |0,g/L

Iron, total recoverable, (J-g/L

Iron, dissolved, |0,g/L

Lead, total recoverable, iig/L

Lead, dissolved, |j,g/L

Manganese, total recoverable, iig/L

Manganese, dissolved, |ig/L

Zinc, total recoverable, iig/L

Zinc, dissolved, |J.g/L

Sediment, suspended, mg/L

Sediment, suspended, percent finer than 0.062 mm

Number of 

replicate pairs

6

6

7

7

7

7

7

7

7

6

7

7

7

7

7

7

5

5

Standard 

deviation, 

in units (+/-)

0.64

.30

.27

.09

.01

.01

.66

.78

6.0

.0

.13

.0

1.1

1.5

.66

1.4

.78

5.3

Relative 

standard 

deviation, 

in percent (+/-)

1.4

2.6

3.6

1.6

7.3

7.3

4.9

16

2.0

.0

9.2

.0

1.1

2.5

1.5

4.2

4.8

6.5

TABLE 9 45
Table 10. Precision of chemical analyses of laboratory replicates for water samples, upper Clark Fork basin, Montana 

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

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, (ig/L

Copper, total recoverable, |ig/L

Copper, dissolved, u,g/L

Iron, total recoverable, (ig/L

Iron, dissolved, |ig/L

Lead, total recoverable, (ig/L

Lead, dissolved, (ig/L

Manganese, total recoverable, |ig/L

Manganese, dissolved, (ig/L

Zinc, total recoverable, (ig/L

Zinc, dissolved, (ig/L

Number of 

replicate pairs

9

9

9

9

9

9

9

9

9

8

9

9

9

9

9

9

Standard 

deviation,1 

in units (+/-)

0.45

.09

.72

.09

.01

.01

.29

.39

2.4

1.8

.02

.12

.78

.45

.18

.06

Relative 

standard 

deviation, 

in percent (+/-)

1.24

.94

14

2.5

43

13

5.4

14

.65

3.1

1.4

54

1.2

1.1

2.2

2.1

Within limits of 

data-quality 

objective

Yes

Yes

Yes

Yes

Yes2

Yes

Yes

Yes

Yes

Yes

Yes

Yes2

Yes

Yes

Yes

Yes

'Statistics calculated using laboratory reporting level for censored values less than the detection capability of the instrument.

2Exceedance of data-quality objective results (relative standard deviation of 20 percent) from a statistical artifact of calculating differences between paired values that are predominantly less than the laboratory reporting level. Because such differences are not fully 

quantified at very low concentrations, the precision estimate may not be representative of analytical performance at detectable concentrations.

46 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

upper Clark Fork Basin, Montana
Table 11. Recovery efficiency for trace-element analyses of laboratory-spiked deionized-water blanks 

[Abbreviation: ug/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

Within limits of

data-quality

objective

Arsenic, total recoverable, (j.g/L 

Arsenic, dissolved, (ig/L 

Cadmium, total recoverable, (ig/L 

Cadmium, dissolved, |J.g/L 

Copper, total recoverable, (j.g/L 

Copper, dissolved, (j.g/L 

Iron, total recoverable, (ig/L 

Iron, dissolved, |J.g/L 

Lead, total recoverable, (ig/L 

Lead, dissolved, |J.g/L 

Manganese, total recoverable, (ig/L 

Manganese, dissolved, |J.g/L 

Zinc, total recoverable, |J.g/L 

Zinc, dissolved, (ig/L

4

4

4

4

4

4

4

4

4

4

4

4

4

4

86.6-109 

92.3-106 

101-115 

98.9-107 

93.7-99.9 

98.6-112 

95.5-107 

86.7-110 

93.7-99.1 

91.9-103 

79.0-125 

89.9-118 

82.7-116 

87.9-116

97.7

99.2

107.9

102.9

96.8

105.2

101.3

98.3

96.4

97.3

101.9

103.7

99.1

102.0

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes

TABLE 11 47
Table 12. Recovery efficiency for trace-element analyses of laboratory-spiked stream samples, upper Clark Fork basin, Montana 

[Abbreviation: |lg/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

Within limits of

data-quality

objective

Arsenic, total recoverable. |ig/L 

Arsenic, dissolved, Hg/L 

Cadmium, total recoverable, Hg 

Cadmium, dissolved, |j.g/L 

Copper, total recoverable, |Ug/L 

Copper, dissolved, |0.g/L 

Iron, total recoverable, Hg/L 

Iron, dissolved, Hg/L 

Lead, total recoverable, |0.g/L 

Lead, dissolved, Hg/L 

Manganese, total recoverable, 

Manganese, dissolved, Hg/L 

Zinc, total recoverable, |0.g/L 

Zinc, dissolved, |0.g/L

4

4

4

4

4

4

4

4

4

4

4

4

4

4

96.7-104 

95.1-110 

95.9-116 

100-106 

87.7-95.9 

104-110 

91.4-100 

92.1-111 

95.3-99.3 

95.2-104 

84.4-116 

90.3-112 

75.9-118 

857 116

100.1

102.8

105.8

103.2

91.8

106.8

95.8

101.6

97.3

99.7

100.0

100.9

96.9

100.8

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes

48 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

upper Clark Fork Basin, Montana
Table 13. Chemical analyses of field blanks for water samples

[Abbreviations: °C, degrees Celsius; |ig/L, micrograms per liter; E, estimated; |lS/cm, microsiemens per centimeter at 25 °C; mg/L, milligrams per liter. 

Symbol: <, less than laboratory reporting level]

c8ondCuct- ^J Calcium, M^' Arsenic, ^otaT Cadmium, ^j]""' 

Date Time ance, (s^Sard dissolved diss ed dissolved recov- dissolved reco°erable

(|?S/cm) units) "" (m8/L) ^ <pH/L) R WU

OCT 2000

31... 0600 2 5.6 E0.01 <0.01 <0.2 <2 <0.14 <0.11

JAN 2001

08... 1100 2 5.7 E.01 <.01 <.2 <2 <.14 <.ll

MAR

21... 1100 2 6.3 E.01 <-01 <.2 <2 <.14 <.ll

MAY

04... 1200 2 5.8 <.01 <.01 <.2 <2 <.14 <.ll

23... 0900 2 5.7 E.01 <.01 <.2 <2 <.10 <.10

JUN

05... 0630 2 5.5 E.01 <.01 <.2 <2 <.10 <.10

JUL

23... 2000 1 6.0 E.01 <.01 <.2 <2 <.10 <.10

SEP

05... 1600 2 5.8 E.01 <.01 <.2 <2 <.10 <.10

Copper,

dissolved

<1.3

 el. 3

<1.3

<1.3

<1.0

<1.0

<1.0

<1.0

CZr Iron' total Lead' total' Manganese, *S2T Zinc, 

Da" recoverable d recoverab.e d recoverable ^^ 

((-ig/L ) (MS* L ) ( Mg* L ) f Lic/L)

OCT 2000

31... <0.6 <10 <10 <1 <1 <0.1 <3 <1

JAN 2001

08... <.6 <10 <10 <1 <1 <.l <3 <1

MAR

21... <.6 <10 <10 <1 <1 <.l <3 <1

MAY

04... <.6 <10 <10 <1 <1 <.l <3 <1

23... <.6 <10 <10 <1 <1 <.l <3 <1

JUN

05... <.6 <10 <10 <1 <1 <.l <3 <1

JUL <1

23.. <.6 <10 <10 <1 <1 E.1 <3

SEP

05... <.6 <10 <10 <1 <1 <.l <3 <1

Zinc, 

total 

recoverable

<1

2

<1

<1

<1

<1

<1

<1

TABLE 13 49
Table 14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, August 2001

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

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

Station number 

(% 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 Crei k near Clinton

Clark Fork at Turah Bridge, 

near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula1

Number 

of composite 

samples

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

Concentration, in |ig/g

Cadmium

41.4

4.2

7.1

7.3

6.4

5.9

5.0

2.3

3.8

7.0

7.7

3.7

7.3

<1.5

2.6

6.0

Chromium

16.8

12.3

26.4

22.3

20.4

21.9

28.2

54.4

28.3

27.2

31.6

21.3

29.0

24.5

30.1

273

Copper

9.020

169

1,090

1,420

1,100

882

839

39

393

59

387

11

352

18

233

107

Iron

37,400

15,400

26,200

26,300

23,100

23,800

26,100

24,200

19,900

19,800

18,300

14,900

17,500

17,800

19,200

20,300

Lead

833

49

131

182

130

121

125

36

61

149

72

12

66

14

47

37

Manganese

3,590

3,220

12,100

4,650

2,920

2,590

2,150

1,520

1,160

2,950

1,150

213

1,060

581

767

986

Nickel

12.7

9.2

16.9

13.4

10.5

9.5

12.2

17.6

11.7

11.2

11.6

9.8

11.5

10.5

11.8

12.4

Silver

20.0

<3.8

7.3

6.4

5.6

4.8

4.0

<1.5

2.8

7.4

3.9

1.9

3.6

<1.5

2.9

3.0

Zinc

10,300

636

1.150

1.300

1,130

1,010

940

165

590

517

785

37

789

53

511

292

'Samples collected about 30 miles downstream from streamflow gaging station to conform to previous sampling location.

50 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

upper Clark Fork Basin, Montana
Table 15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, August 2001

FBulk bed sediment collected in this study generally is material smaller than about 10 millimeters in diameter. Reported concentrations are the mean of all 

analyses for replicate aliquots of 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

1234000

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek ai 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

Number 

of composite 

samples

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

Concentration, in ug/g

Cadmium

22.2

<2.6

3.5

3.1

2.7

2.9

<2.6

<1.5

<2.6

3.8

4.7

<1.5

4.9

<1.5

<1.5

2.0

Chromium

14.5

5.3

15.8

12.2

10.1

14.1

19.6

32.1

15.0

11.4

17.5

8.0

20.3

19.2

17.2

7.4

Copper

2,780

32

584

599

475

283

363

12

197

16

162

3

198

16

64

17

Iron

27,500

9,910

16,300

19,400

18,200

23,500

19,200

17,300

15,400

12.800

13,400

7,170

13,400

17,000

16,200

8,850

Lead

363

12

79

89

59

57

62

14

37

55

35

4

41

11

20

9

Manganese

2,590

698

6,810

1,840

974

1,130

607

333

706

1,660

656

74

642

368

388

249

Nickel

9.2

5.4

9.3

6.8

5.5

5.8

9.3

11.7

9.0

5.2

9.2

4.5

9.0

9.6

9.1

4.9

Silver

7.1

<2.6

3.5

<2.6

2.9

3.0

<2.6

<1.5

<2.6

5.2

2.1

<1.5

2.6

<1.5

<1.5

<1.5

Zinc

5,110

126

649

598

541

441

499

65

368

201

470

7

485

47

218

69

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

TABLE 15 51
Table 16. Recovery efficiency for trace-element analyses of standard reference materials for bed sediment

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

all analyses were less than the analytical detection limit]

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number of 

measurements

9

9

9

9

9

9

9

9

9

9

9

9

9

9

9

9

9

9

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

(Mfife)

SRM sample 2709

04

130

35

35,000

19

538

88

.4

106

SRM sample 2711

41.7

47.0

114

28,900

1,160

638

20.6

4.6

350

Mean SRM 

recovery (percent)

76.4

80.5

88.7

90.4

86.5

87.9

-

71.8

99.7

47.6

88.8

90.4

102.9

81.1

85.9

100.8

90.0

95-percent confidence 

interval for SRM 

recovery 

(percent)

--

73.5-79.2

78.9-82.1

86.8-90.6

89.2-91.7

84.8-88.1

86.3-89.5

-

70.5-73.2

99.1-100

44.0-51.3

88.1-89.6

89.6-91.1

102-103

80.6-81.7

85.0-86.9

90.1-112

88.5-91.4

52 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

upper Clark Fork Basin, Montana
Table 17, Trace-element analyses of procedural blanks for bed sediment

[Abbreviation: HgtoL, 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]

Trace-element concentration, i

Station number

12323600

12323750

12323800

461415112450801461559112443301461903112440701

12324200

12324590

12324680

12331500

12331800

12334510

12334550

1234000012340500

12353000

Station name ratio

Silver Bow Creek at Opportunity 1 : 1

Silver Bow Creek at Warm Springs 1 : 1

Clark Fork near Galen 1:1Clark Fork below Lost Creek, near Galen 1 : 1Clark Fork near Racetrack 1 : 1Clark Fork at Dempsey Creek diversion, near Racetrack 1 : 1Clark Fork at Deer Lodge 1:1Little Blackfoot River near Garrison 1 : 1Clark Fork at Goldcreek 1:1

Flint Creek near Drummond 1 : 1

Clark Fork near Drummond 1 : 1

Rock Creek near Clinton 1 : 1

Clark Fork at Turah Bridge, near Bonner 1:1

Blackfoot River near Bonner 1 : 1

Clark Fork above Missoula 1 : 1

Clark Fork below Missoula 1 : 1

Cadmium

<0.02

<.02<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02<.02<.02<.02

<.02

Chro- Copmium per

<0.012 <0.01

<.012 <.01

<.012 <.01

<.012 <.01<.012 <.01<.012 <.01<.012 <.01<.012 <.01<.012 <.01<.012 <.01<.012 <.01

<.012 <.01

<.012 <.01

<.012 <.01

<.012 <.01

<.012 <.01

Iron

<0.03

<.03

<.03

<.03<.03<.03

<.03

1.67

<.03<.03<.03

<.03

<.03

<.03

<.03<.03

Lead

<0.006

<.006

<.006

<.006

<.006

<.006

<.006

<.006

<.006

<.006

<.006<.006

<.006<.006<.006<.006

Manganese

<0.05

<.05<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05<.05

<.05

Nickel

<0.003

<.003<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003<.003<.003<.003<.003<.003<.003

Silver

<0.02

<.02<.02<.02<.02<.02<.02<.02<.02<.02<.02

<.02

<.02<.02<.02

<.02

Zinc

<0.097

<.097

<.097

<.097

<.097

<.097<.097<.097

<.097

<.097

<.097

.110

<.097

<.097<.097<.097

B

-J
Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 2001

[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: u.g/g, micrograms per gram of dry sample weight; spp, species. Symbol: <, less than minimum reporting level]

Number of Concentration, in u.g/g

Taxon

Hydropsyche spp.

Hydropsyche cockerelli

Hydropsyche occidentatis

Hydropsyche cockerelli

Hydropsyche occidentalis 

Hydropsyche cockerelli

Hydropsyche cockerelli

Hydropsyche occidentalis 

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche cockerelli

Hydropsyche occidentalis 

Arctopsyche grandis

Claassenia sabulosa

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Arctopsyche grandis

Hydropsyche cockerelli

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

composite Cad- Chro- Cop- Irw] 

samples mium miiim per

12323600 Silver Bow Creek at Opportunity

2 10.6 1.2 864 1,510

12323750 Silver Bow Creek at Warm Springs

2 .4 .5 25.2 535

1 .4 1.0 11.0 744

12323800 Clark Fork near Galen

2 2.0 1.9 79.5 1,230

2 1.2 2.8 81.5 1,470 

461415112450801 Clark Fork below Lost Creek, near Galen

1 2.2 1.0 81.6 691

461559112443301 Clark Fork near Racetrack

3 1.4 1.1 62.8 686

Lead

42.7

1.4

1.9

6.1

7.5 

4.5

4.0

1 .8 1.8 66.8 1,140 7.2 

461903112440701 Clark Fork at Dempsev Creek diversion, near Racetrack

3 1.5 .8 77.4 747

1 1.2 1.6 79.9 940

12324200 Clark Fork at Deer Lodge

1 2.2 I.I 97.7 1,040

3 1.2 1.8 92.0 1,130 

12324590 Little Blackfoot River near Garrison

5 .7 .9 13.7 585

2 .2 .3 29.2 178

12324680 Clark Fork at Goldcreek

3 2.0 1.2 27.4 866

1 .3 .5 64.7 567

2 .8 .7 23.4 667

12331500 Flint Creek near Drummond

1 .2 .3 8.9 412

1 .2 2.0 21.0 2,320

12331800 Clark Fork near Drummond

2 1.2 .4 18.2 418

4 .6 .2 69.8 176

4 .7 .8 32.7 846

1 .8 1.5 38.9 1,190

39

6.1

7.1

9.2 

.8

.2

2.9

1.8

3.6

7.6

20.5

4.5

.9

8.0

14.0

Manganese

893

1,420

2,160

3,270

5,160 

1,720

1,950

3,770 

1,200

2,720

1,200

2,270 

997

76

870

279

869

424

1,450

797

152

1,070

2,390

Nickel

2.0

1.0

1.1

1.5

1.9 

1.0

.7

1.3

.7

1.2

.9

1.3 

1.1

.5

.8

.5

.5

1.2

1.8

.5

.3

.8

1.2

Zinc

1,210

149

141

204

227 

181

164

200 

183

237

207

259 

197

196

235

203

140

933

205

196

295

177

228

54 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2001 (Continued)

Taxon

Arctopsyche grandis

Claassenia sabulosa 

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Number o 

composite 

samples

4

f Concentration, in |ig/g

Cad- Chro- Cop- Iron mium niiuni per

12334510 Rock Creek near Clinton

.2 1.3 9.1 977

2 .2 .2 22.5 104 

12334S50 Clark Fork at l\irah Bridee. near Bonner

4

1

2

1

4

1

1

1

2

4

1

.7 1.0 29.2 856

.4 .1 43.2 142

.6 1.4 46.8 1,360

.6 1.7 46.5 1,390

12340500 Clark Fork above Missoula

.5 .8 27.2 570

.4 .4 46.8 229

.5 1.8 44.1 1,490

12353000 Clark Fork below Missoula1

.4 .8 13.2 682

.2 .3 60.8 139

.3 1.7 23.2 1,520

.3 1.4 20.0 1,200

Lead

.4

.1

4.9

.5

6.7

8.4

2.4

.8

5.5

1.4

.1

2.4

2.7

Manganese

310

33 

729

57

712

998

934

394

1,470

870

108

833

491

Nickel

1.5

.4 

1.0

.3

1.4

1.5

.9

.3

1.4

.7

.2

1.4

1.3

Zinc

143

150 

190

206

201

223

144

191

167

140

206

136

137

Samples collected about 30 miles downstream from streamflow-gaging station to conform to previous sampling location.

TABLE 18 55
Table 19. Recovery efficiency for trace-element analyses of standard reference material for biota 

[Abbreviations: |ig/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

'0

12

12

12

Certified concentration

(H8/g)

SRM sample TORT-2

26.7

.77

106

105

.35

13.6

2.5

180

Mean SRM recovery 

(percent)

90.5

79.1

89.5

83.3

-

83.9

89.3

89.5

95-percent confidence 

interval for SRM 

recovery 

(percent)

87.1-93.9

70.7-87.4

87.7-91.2

78.0-88.6

-

78,4-89.4

69.3-109

83.1-96.0

'Certified lead concentration in SRM was below the analytical detection limit.

56 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana
Table 20. Trace-element analyses of procedural blanks for biota

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

Trace-element concentration, in ug/mL

Station 

number

Station 

name

Dilution 

ratio Cad- Chro- Manga- ... , , _. Copper Iron Lead Nickel Zinc mium mium nese

12323600

12323750

12323800

461415112450801

461559112443301

461903112440701

12324200

12324590

12324680

12331500

12331800

12334550

12340500

12353000

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

Clark Fork at Turah Bridge, near Bonner

Clark Fork above Missoula

Clark Fork below Missoula

1:1 <0.05

1:1 <.05

1:1 <.05

1:1 <05

1:1 <.05

1:1 <.05

1:1 <05

1:1 <.05

1:1 <.05

1:1 <05

1:1 <.05

1:1 <.05

1:1 <.05

1:1 <05

<0.05

<.05

<05

<05

<.05

<05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<0.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<0.10 <0.01 <0.02

<.10 <.01 <.02

<.10 <.01 <.02

<.10 <01 <.02

<10 <01 <.02

<10 <-01 <.02

<.10 <01 <.02

<.10 <.01 <.02

<10 <-01 <.02

<.10 <.01 <.02

<.10 <01 <.02

<10 <01 <.02

<.10 <.01 <.02

<.10 <01 <.02

<0.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<.05

<0.02

<.02

<.02

<.02

<02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

TABLE 20 57
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 2001

[Abbreviations: ft3/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 laboratory reporting level1 ; , indicates insufficient data greater than minimum reporting 

level to compute statistic]

Property or constituent and reporting unit

Number of 

samples

Maximum Minimum

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

Period of record for water-quality data

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (|J,S/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 (jJ.g/L)

Arsenic, dissolved (jJ.g/L)

Cadmium, total recoverable Qig/L)

Cadmium, dissolved (jJ.g/L)

Copper, total recoverable Qig/L)

Copper, dissolved (|ig/L)

Iron, total recoverable (jJ.g/L)

Iron, dissolved (fig/L)

Lead, total recoverable (jJ.g/L)

Lead, dissolved (|ig/L)

Manganese, total recoverable (|ig/L)

Manganese, dissolved (|ig/L)

Zinc, total recoverable Qig/L)

Zinc, dissolved (|ig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

: March 1993-August 1995,

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

156

412

17.5

8.2

150

42

11

18

13

.05

.5

52

10

4,200

480

47

1

240

100

130

11

139

59

97

Mean

MONT.

Median

December 1996-September 2001

1.9

116

2.0

7.3

38

11

2.7

2

1

<.l

<.l

2

<.8

140

20

<1

<.5

24

17

<10

<3

2

.02

50

16

261

8.1

7.8

103

29

7.2

6

4

-

2<.l

7

24

743

170

23

2.3

62

42

2 11

24

16

1.7

83

8.3

262

7.5

7.8

110

31

7.3

4

3

<1

<.l

6

3

570

160

1

<.5

55

40

3

2

8

.16

86

58 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2001 (Continued)

Property or constituent and reporting unit

Number of 

samples

12323250-SILVER BOW CREEK BELOW BL

Maximum Minimum

ACKTAIL CREEK. AT BUTTE

Mean

. MONT.

Median

Period of record for water-quality data: March 1993-August 1995, December 1996-September 2001

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (ilS/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 ((lg/L)

Cadmium, total recoverable (ilg/L)

Cadmium, dissolved (iig/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 (|ig/L)

Manganese, total recoverable (iig/L)

Manganese, dissolved (|ig/L)

Zinc, total recoverable (iig/L)

Zinc, dissolved (iig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

67

66

66

66

134

691

20.0

8.1

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

98

13

226

1.0

7.2

66

19

4.5

7

4

.7

.2

16

6

90 1

<10

1

<.5

160

137

178

118

3

.14

42

32

463

10.0

7.6

147

42

10

14

7

2.4

1.8

138

59

,250

297

22

2.7

597

539

717

593

34

4.2

83

26

470

9.0

7.5

150

43

11

12

7

2

1.4

106

47

760

84

10

<1

590

500

570

488

14

1.1

86

TABLE 21 59
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 2001 (Continued)

Property or constituent and reporting unit

12323600-SILVER

Number of 

samples

BOW CREEK

Maximum Minimum Mean Median

AT OPPORTUNITY. MONT.

Period of record for water-quality data: March 1993-August 1995,

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite ((xS/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 ((ig/L)

Arsenic, dissolved ((ig/L)

Cadmium, total recoverable ((xg/L)

Cadmium, dissolved ((xg/L)

Copper, total recoverable ((xg/L)

Copper, dissolved ((Xg/L)

Iron, total recoverable ((xg/L)

Iron, dissolved Qig/L)

Lead, total recoverable ((xg/L)

Lead, dissolved (Hg/L)

Manganese, total recoverable ((xg/L)

Manganese, dissolved ((xg/L)

Zinc, total recoverable ((xg/L)

Zinc, dissolved Qig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

70

69

69

69

69

69

69

69

69

69

69

69

69

69

69

69

69

69

69

69

69

70

70

70

361

616

22.5

9.5

220

63

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

December 1996-Sept ember 2001

13

202

0.0

7.2

60

18

3.4

11

1

.6

.1

60

19

260

<10

7

<.5

174

68

144

27

6

.25

37

81

395

9.0

8.3

140

41

9.0

31

10

2.9

1.7

281

58

1,900

253

49

2.8

734

599

751

450

63

29

77

54

383

9.0

8.3

140

41

8.6

18

9

2.0

1.1

140

46

890

27

17

<1

545

460

480

260

20

3.2

82

60 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

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

irough September 2001 (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 (ft3/s)

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 (fig/L)

Arsenic, dissolved (fig/L)

Cadmium, total recoverable (|ig/L)

Cadmium, dissolved (fig/L)

Copper, total recoverable (fig/L)

Copper, dissolved (fig/L)

Iron, total recoverable (fig/L)

Iron, dissolved (^g/L)

Lead, total recoverable (fig/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (fig/L)

Manganese, dissolved (fig/L)

Zinc, total recoverable (fig/L)

Zinc, dissolved (fig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

76

74

75

74

74

74

74

74

74

74

74

74

74

74

74

74

74

74

74

74

74

76

76

75

March 1993-September 2001

662

783

22.0

9.3

310

90

21

94

60

.2

.3

80

40

3,000

90

15

1.0

900

880

180

73

229

279

97

16

249

.5

8.0

97

28

5.9

10

7

<.l

<.l

3

2

70

<5

<1

<.5

60

12

<10

<3

1

.11

43

155

460

10.9

8.8

190

55

13

26

21

2<.l

2.1

21

11

383

220

22

-

201

130

245

2 11

13

9.7

82

99

458

11.5

8.8

190

55

12

24

21

<1

<.l

16

9

300

20

2

<.5

159

96

30

7

7

1.9

84

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

through September 2001 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum

12323770--WARM SPRINGS CREEK AT WARM

Period of record for water quality data:

Streamflow, instantaneous (ft /s)

Specific conductance, onsite (|J,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 (|J,g/L)

Arsenic, dissolved (Hg/L)

Cadmium, total recoverable (Hg/L)

Cadmium, dissolved (|J.g/L)

Copper total recoverable (ng/L)

Copper, dissolved (ng/D

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (Hg/L)

Lead, dissolved (|ag/L)

Manganese, total recoverable (|J.g/L)

Manganese, dissolved (Hg/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (|J.g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

52

51

52

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

52

51

52

Minimum

SPRINGS. MONT.

Mean Median

March 1993-September 2001

420

795

18

8.7

420

130

22

27

14

.2

<.l

97

16

1,700

30

14

1.8

1,400

570

60

10

100

87

88

2.8

139

.5

7.4

66

20

3.6

3

2

<.l

<.l

2

1

40

<5

<1

<.5

57

29

<10

<1

2

.05

55

104

304

8.9

8.3

147

45

8.5

8

5

--

-

21

4

336

2 14

22

-

241

148

2 11

23

20

11

74

57

269

9.0

8.3

130

40

7.4

6

4

<1

<.l

10

3

130

10

<1

<.5

200

110

2

<20

10

1.2

75

62 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2001 (Continued)

Property or constituent and reporting unit Number of 

samples

12323800--CLARK FORK

Period of record

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite ((0,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 (|ig/L)

Arsenic, dissolved ((ig/L)

Cadmium, total recoverable (|ig/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (|ig/L)

Copper, dissolved (jig/L)

Iron, total recoverable (|ig/L)

Iron, dissolved (Jig/L)

Lead, total recoverable (|ig/L)

Lead, dissolved (|ig/L)

Manganese, total recoverable (Hg/L)

Manganese, dissolved (|ig/L)

Zinc, total recoverable (|ig/L)

Zinc, dissolved (Hg/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

for water-quality

117

105

116

104

103

103

103

103

103

103

103

102

103

103

103

103

103

103

103

103

103

117

117

Sediment, suspended (percent finer than 0.062 mm) 1 1 6

Maximum

NEAR GALEN.

Minimum

MONT.

Mean Median

data: July 1988-September 2001

1,050

720

22.5

9.0

370

110

22

78

53

3

1

240

50

9.200

110

28

3

1,400

460

360

110

338

459

97

14

197

0.0

7.5

81

24

5.1

3

4

<.l

<1

5

2

60

<3

<1

<.5

47

25

<10

<3

2

.12

41

216

430

9.7

8.5

187

55

12

20

15

2.2

2.07

33

10

574

221

24

2.3

265

121

252

2 13

21

24

78

129

438

9.8

8.5

190

57

12

16

12

<1

<.l

19

8

300

20

2

<.6

200

89

40

9

8

2.5

78

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

through September 2001 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12324200-CLARK FORK AT DEER LODGE. MONT. 

Period of record for water-quality data: March 1985-September 2001

Streamflow, instantaneous (ft3/s) 169 1,920 23 298 225

Specific conductance, onsite (iiS/cm) 152 642 234 488 506

Temperature, water (°C) 168 23.0 0.0 9.6 10.0

pH, onsite (standard units) 117 8.9 7.4 8.2 8.3

Hardness, total (mg/L as CaCO3) 109 270 95 205 210

Calcium, dissolved (mg/L) 109 81 28 60 62

Magnesium, dissolved (mg/L) 109 18 5.9 13 14

Arsenic, total recoverable (ng/L) 119 220 8 26 17

Arsenic, dissolved (|ig/L) 119 39 6 14 13

Cadmium, total recoverable (ng/L) 119 5 <.l 2.5 <1

Cadmium, dissolved ()J.g/L) 119 2 <.l 2.06 <.l

Copper, total recoverable (ng/L) 118 1,500 8 99 44

Copper, dissolved (ng/L) 119 120 4 12 9

Iron, total recoverable (ng/L) 119 29,000 30 1,910 690

Iron, dissolved (|ig/L) 119 190 <3 221 10

Lead, total recoverable (\igfL) 119 200 <1 2 13 5

Lead, dissolved (ng/L) 119 6 <5 2.5 <1

Manganese, total recoverable ()J.g/L)

Manganese, dissolved (|0.g/L)

Zinc, total recoverable (Hg/L)

Zinc, dissolved (|0.g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

119

119

119

119

169

169

160

4,600

400

1,700

230

2,250

8,690

9<3

12

1

4

<10

2

.29

40

293

45

111

2 15

82

186

71

170

33

60

11

24

12

72

64 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2001 (Continued)

Property or constituent and reporting unit

12324590--LITTLE BL

Number of 

samples Maximum Minimum Mean Median

ACKFOOT RIVER NEAR GARRISON. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (|O.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 (|ig/L)

Arsenic, dissolved (|J.g/L)

Cadmium, total recoverable (jig/L)

Cadmium, dissolved ((ig/L)

Copper, total recoverable (Hg/L)

Copper, dissolved ((ig/L)

Iron, total recoverable (|J.g/L)

Iron, dissolved (jlg/L)

Lead, total recoverable ((ig/L)

Lead, dissolved ((ig/L)

Manganese, total recoverable (|J,g/L)

Manganese, dissolved ((ig/L)

Zinc, total recoverable ((ig/L)

Zinc, dissolved ((ig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

96

84

95

83

78

78

78

83

83

83

83

82

83

83

83

83

82

83

83

83

83

96

96

96

March 1985-September 2001

2,080

338

22

8.5

160

47

10

17

7

2

1

45

7

25,000

120

25

6

1,100

45

140

24

1,410

7,920

97

15

120

0.0

7.0

51

14

3.3

4

3

<.l

<.l

<1

<1

20

<3

<1

<.5

<10

1

<1

<1

1

.08

32

292

228

8.3

8.1

105

30

7.0

7

5

2 .2

-

24

22

1.170

245

23

2 .4

271

9

2 13

23

53

144

74

178

221

9.0

8.1

100

30

7.0

6

5

<1

<.l

3

2

260

30

<5

<1

30

8

<40

<20

10

4.4

79

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

through September 2001 (Continued)

Property or constituent and reporting unit

12324680--CI

Number of 

samples Maximum

,ARK FORK AT GOLDCREEK

Period of record for water-quality data:

Streamflow, instantaneous (ft /s)

Specific conductance, onsite ((iS/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 ((lg/L)

Arsenic, dissolved ((ig/L)

Cadmium, total recoverable ((ig/L)

Cadmium, dissolved ((ig/L)

Copper, total recoverable (|ig/L)

Copper, dissolved (|ig/L)

Iron, total recoverable ((ig/L)

Iron, dissolved ((ig/L)

Lead, total recoverable ((ig/L)

Lead, dissolved ((lg/L)

Manganese, total recoverable ((ig/L)

Manganese, dissolved ((ig/L)

Zinc, total recoverable ((ig/L)

Zinc, dissolved ((ig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

75

74

75

74

74

74

74

74

74

74

74

73

73

74

74

73

73

74

74

74

74

75

75

75

Minimum

MONT.

Mean Median

March 1993-September 2001

3,920

510

21.5

8.8

230

68

15

75

20

2

.2

440

36

12,000

100

73

.8

1,100

57

510

26

752

7,960

93

87

207

0.0

7.9

86

26

5.1

7

6

<.l

<.l

5

3

30

<3

<1

<.5

10

4

2

<1

2

.94

43

786

372

9.5

8.3

163

48

10

16

10

2.2

-

48

8

1,050

223

27

--

144

21

57

27

62

291

75

529

392

9.5

8.3

170

51

11

13

10

<]

<.l

33

6

510

20

4

<.5

100

20

39

5

23

37

78

66 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2001 (Continued)

Property or constituent and reporting unit Number of 

samples

12331500-FLINT CREEK NEAR

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 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 (Hg/L)

Copper, total recoverable (|J.g/L)

Copper, dissolved (Hg/L)

Iron, total recoverable (Hg/L)

Iron, dissolved (|J.g/L)

Lead, total recoverable (ng/L)

Lead, dissolved (|J.g/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (Hg/L)

Zinc, total recoverable (|J.g/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

123

112

121

109

102

102

102

109

109

109

109

108

109

109

109

109

109

109

109

109

109

123

120

123

Maximum Minimum

DRUMMOND. MONT.

Mean Median

March 1985-September 2001

892

529

21.0

8.8

260

73

20

57

20

3

.1

32

7

7,200

240

87

7

1,600

140

290

27

556

904

98

2.8

134

0.0

7.5

59

16

4.3

7

5

<.l

<.l

1

<1

60

<10

<1

<.5

50

14

<10

<1

3

.02

28

189

301

9.0

8.3

141

38

11

18

9

2.2

-

7

22

928

240

2 12

2.7

216

42

239

25

53

48

80

121

300

9.5

8.3

140

38

11

13

8

<1

<.l

5

2

480

26

7

<1

132

34

28

3

27

8.6

84

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

through September 2001 (Continued)

Property or constituent and reporting unit Number of 

samples

12331800--CLARK FORK NEAR

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 CaCO3 )

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (Hg/L)

Arsenic, dissolved (Hg/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (Hg/L)

Copper, total recoverable (Hg/L)

Copper, dissolved (Hg/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (Hg/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (Hg/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (Hg/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

75

74

75

74

74

74

74

74

74

74

74

72

72

74

74

70

70

74

74

74

74

75

75

75

Maximum Minimum Mean Median

DRUMMOND. MONT.

March 1993-September 2001

3,860

630

22.5

8.5

300

83

22

62

20

2

.2

360

21

8,800

150

56

1.2

880

61

490

21

530

4,720

92

149

189

.5

7.8

74

21

5.2

8

7

<.l

<.l

5

1

20

<3

<1

<.5

8

4

3

<3

2

1.7

38

1,100

406

10.4

8.3

183

52

13

17

11

2.2

2<.l

50

7

1,180

225

29

2.3

167

18

74

27

75

393

74

817

429

11.0

8.3

190

55

13

14

10

<1

<.l

24

5

540

20

4

<.5

106

15

42

5

29

64

75

68 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2001 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum

12334510-ROCK CREEK NEAR CLINTON.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (|iS/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 (|ig/L)

Arsenic, dissolved (|ig/L)

Cadmium, total recoverable (|ig/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (|ig/L)

Copper, dissolved (|ig/L)

Iron, total recoverable (|ig/L)

Iron, dissolved (|ig/L)

Lead, total recoverable (|ig/L)

Lead, dissolved (|ig/L)

Manganese, total recoverable (|ig/L)

Manganese, dissolved (|ig/L)

Zinc, total recoverable (|ig/L)

Zinc, dissolved (|ig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

95

86

95

85

77

77

77

83

83

83

83

81

82

83

83

81

81

83

83

83

83

95

95

95

Minimum

MONT.

Mean Median

March 1985-September 2001

5,060

158

18

8.8

90

23

8.0

3

1

3

1

41

6

2,100

160

19

5

90

8

60

15

223

3,050

95

113

53

0.0

6.9

22

5.9

1.9

<1

<1

<.l

<.l

<1

<1

20

<10

<1

<.5

<1

<1

<1

<1

1

.31

35

989

106

82

7.9

50

13

4.2

2.9

2.6

2.3

-

24

2 1

317

234

22

2.5

2 16

22

27

22

22

152

69

558

99

8.5

7.9

49

13

4.0

<1

<1

<1

<.l

2

<1

140

30

<1

<1

9

2

<10

<3

6

12

71

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

through September 2001 (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

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (|j.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 (|J.g/L)

Arsenic, dissolved (|J.g/L)

Cadmium, total recoverable (|J.g/L)

Cadmium, dissolved (|J.g/L)

Copper, total recoverable (|J.g/L)

Copper, dissolved (|J.g/L)

Iron, total recoverable (|J.g/L)

Iron, dissolved (|J.g/L)

Lead, total recoverable (|ig/L)

Lead, dissolved (|J.g/L)

Manganese, total recoverable (|J.g/L)

Manganese, dissolved (|J.g/L)

Zinc, total recoverable (|ig/L)

Zinc, dissolved (|J.g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

172

147

171

118

108

108

108

117

117

117

117

115

116

117

117

113

113

117

117

117

117

172

172

161

Minimum Mean Median

BONNER. MONT.

: March 1985-September 2001

9,560

483

22.0

8.8

210

59

14

110

17

4

I

500

25

19,000

190

100

7

2,000

37

1,100

39

1,370

34,700

98

296

140

0.0

7.4

58

16

3.9

3

3

<.l

<.l

3

2

50

<3

<1

<.5

10

1

<10

<3

2

3.5

27

1,870

307

9.3

8.2

134

38

9.6

11

6

2.3

--

42

5

1,270

232

29

2.4

149

8

276

27

64

722

73

1,120

327

9.5

8.3

140

39

9.6

8

5

<1

<.l

19

4

450

20

4

<1

80

7

40

5

20

61

73

70 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 2001 (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 (|J.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 (|J.g/L)

Arsenic, dissolved (|J.g/L)

Cadmium, total recoverable (|J.g/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (|J.g/L)

Copper, dissolved (M-g/L)

Iron, total recoverable (|J.g/L)

Iron, dissolved (|ig/L)

Lead, total recoverable (|J.g/L)

Lead, dissolved (|J.g/L)

Manganese, total recoverable (|J.g/L)

Manganese, dissolved (|J.g/L)

Zinc, total recoverable (|ig/L)

Zinc, dissolved (|J.g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

126

103

126

86

79

79

79

86

86

86

86

83

84

86

86

82

82

86

86

86

86

126

126

124

March 1985-September 2001

13,400

294

21.0

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

131

0.0

7.5

55

14

4.9

<1

<1

<.l

<.l

<1

<1

20

<3

<1

<.5

<10

<1

<1

<1

1

1.1

42

2,710

206

9.1

8.3

101

26

9.0

2 1

2.9

2.2

-

26

22

520

223

24

2.8

234

23

27

23

32

586

79

1,320

205

9.2

8.3

97

25

8.5

1

.9

<1

<.l

3

1

230

20

<5

<1

20

2

<10

<3

9

31

82

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

through September 2001 (Continued)

Property or constituent and reporting unit

12340500--CL

Number of ... Maximum samples

ARK FORK ABOVE

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (|iS/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 (|ig/L)

Arsenic, dissolved (|ig/L)

Cadmium, total recoverable (Hg/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (|lg/L)

Copper, dissolved Qig/L)

Iron, total recoverable (|ig/L)

Iron, dissolved (|ig/L)

Lead, total recoverable (|ig/L)

Lead, dissolved (|J.g/L)

Manganese, total recoverable (|ig/L)

Manganese, dissolved (|ig/L)

Zinc, total recoverable (|ig/L)

Zinc, dissolved (|ig/L)

Sediment, suspended concentration (mg/L)

Sediment suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

138

115

135

95

95

95

95

95

95

95

95

93

94

95

95

90

90

95

95

95

95

138

138

133

MISSOUL

Minimum

A. MONT.

Mean Median

July 1986-September 2001

21,600

399

20.0

8.7

170

46

13

69

9

5

.1

400

11

13,000

200

78

1

1,100

230

1,100

16

824

21,900

99

720

142

0.0

7.9

61

14

5.3

1

I

<.l

<.l

2

.7

40

<3

<1

<.5

10

6

<10

<1

2

5.8

44

4,430

256

9.2

8.3

118

32

93

5

3

2.2

-

17

3

630

225

23

2 6

67

18

232

24

38

1,010

87

2,330

267

8.5

8.3

120

32

9.5

4

3

<1

<.l

8

2

220

20

I

<.6

40

14

13

2

10

60

90

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

2Value is estimated by using a log-probability regression to predict the values of data less than the laboratory reporting level (Helsel and Cohn, 1988).

72 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 September 2001

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

weight. Symbols: <, less than minimum reporting level; , indicates 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]

Number

Constituent of

samples

JYlSiXl"

mum

Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for fine-grained bed-sediment data: 1992-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

10

9

10

10

10

10

9

10

10

42.0

32.4

9,020

41,200

1,030

9.220

21.4

20.0

13,400

23.7

16.8

4,220

28,200

563

1.690

12.7

13.1

6,660

32.5

26.5

5,390

37,300

818

3,310

18.9

16.6

8,820

32.0

27.6

4.820

38,000

833

2,530

16.0

16.8

8,340

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.

Period of record for fine-grained bed-sediment data: 1992-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

10

9

10

10

10

10

9

10

10

12.2

34.1

769

27,200

100

17,700

19.1

2.1

2.220

4.2

12.3

169

15,400

49

1.470

9.2

.3

620

7.4

21.0

391

21,000

72

6,980

14.8

'l.5

1,100

6.7

22.9

308

20,600

68

5,590

15.4

'1.6

830

12323770-WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

Period of record for fine-grained bed-sediment data: 1995, 1997, 1999

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

3

3

3

3

3

3

3

3

3

3.9

33.4

892

22,400

86

8,790

21.9

3.7

421

1.3

27.5

779

20,600

85

2.020

17.6

3.1

372

2.6

30.6

840

21,600

85

5,610

19.7

3.3

396

2.6

30.8

848

21,900

85

6,030

19.6

3.2

396

12323800--CLARK FORK NEAR GALEN. MONT.

Period of record for fine-grained bed-sediment data: 1987, 1991-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

12

9

12

12

12

12

9

12

12

20.1

33.9

2,300

39,800

235

15,600

23.2

7.3

3,560

4.0

19.1

991

22,600

116

2,780

15.4

<3.2

1,090

10.1

27.1

1,310

28,800

149

8,760

19.0

'4.3

1,780

8.5

27.0

1,220

28,100

139

8,510

19.0

3.9

1,370

TABLE 22 73
Table 22. Statistical summary of fine-grained bed-sediment data for the upper Clark Fork basin, Montana, 

August 1986 through September 2001 (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

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

Period of record for fine-grained bed-sediment data: 1996-2001

6 10.5 6.5 8.1

6 34.5 22.3 29.1

6 2,050 1,360 1,610

6 32,800 26.300 30,900

6 200 168 185

6 5,900 3,540 4,800

6 19.9 13.4 17.5

6 7.8 4.2 6.3

6 1,680 1,280 1,450

4615591 12443301-CLARK FORK NEAR RACETRACK. MONT.

Period of record for fine-grained bed-sediment data: 1996-2001

6 8.6 5.0 6.9

6 33.3 19.1 26.3

6 1.610 933 1.220

6 31,700 23,100 27,800

6 186 128 148

6 4,120 2,390 3,210

6 18.4 10.5 15.3

6 6.1 <3.3 '4.9

6 1,550 1,030 1,250

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

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: 1996-2001

6 10.3 4.3 6.7

6 34.1 16.0 26.4

6 1,550 766 1,070

6 33,700 22,000 27,700

6 152 115 131

6 6,410 1,810 3,340

6 16.9 9.5 14.1

6 6.2 2.7 4.8

6 1,570 900 1,170

12324200--CLARK FORK AT DEER LODGE. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1990-2001

14 10.0 4.4 6.9

9 43.9 19.5 31.5

14 4,180 837 1.440

14 35,300 22,600 28,300

14 242 121 158

14 6,020 1,460 2,800

9 21.1 12.2 16.7

14 7.9 2.4 4.7

14 1,730 940 1,310

Median

7.9

29.8

1,550

31,600

186

4,830

18.3

6.6

1,470

7.0

27.5

1.230

28,800

144

3,020

16.6

'5.3

1,180

MONT.

6.4

27.6

990

28,200

126

2,660

15.5

5.0

1,140

6.8

32.5

1,130

28,900

153

2,380

16.8

4.5

1,330

74 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 September 2001 (Continued)

_ . Number of Constituent . samples

MaxiMinimum Mean 

mum

Median

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1994, 1998, 2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

5

3

5

5

5

5

5

5

5

2.3 .2 1.1

54.4 22.1 43.1

85 38 56

30,700 16,100 24,200

53 36 40

2,700 905 1,420

21.9 13.6 17.7

.9 <.5 '.6

204 161 176

.9

52.9

40

24,200

37

1,040

17.6

'.8

170

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for fine-grained bed-sediment data: 1992-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

10

9

10

10

10

10

9

10

10

8.1 3.5 5.5

48.9 24.9 33.8

1,080 393 780

30.600 19,900 25,100

152 61 108

2,610 1,160 1.850

18.6 11.7 16.0

4.8 2.3 3.5

1,320 590 1,090

5.7

31.9

773

24,900

112

1,810

16.4

3.4

1,120

12331500--FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for fine-grained bed-sediment data: 1986, 1989, 1992-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

12

9

12

12

12

12

9

11

12

7.0 <.2 '3.0

29.2 20.4 24.7

73 55 62

28,100 19,800 23,700

240 149 176

5,510 2,370 3,760

14.9 11.2 12.7

7.8 5.0 6.4

777 517 647

'2.8

24.3

63

23,400

171

3,740

12.5

6.5

649

12331800--CLARK FORK NEAR DRUMMOND. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1991-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

13

9

13

13

13

13

9

13

13

7.7 2.6 4.7

35.4 17.0 29.5

747 387 534

27.000 16,500 22,300

135 72 97

2,790 1,150 1,780

16.8 11.6 14.2

4.7 <3.2 '3.0

1,230 785 1,050

4.8

31.6

550

23,200

97

1,740

15.7

'2.9

1,040

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

Augusl 1986 through September 2001 (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

12334510--ROCK CREEK NEAR CLINTON. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1989, 1991-99, 2001

13 3.7 <.2 '.6

8 27.9 16.5 22.4

13 16 3 12

13 21,400 13,100 17,900

13 16 <3 '8

13 724 126 390

8 14.8 9.8 12.5

12 1.9 <.3 '.5

13 58 36 47

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

Period of record for fine-grained bed-sediment data: 1986, 1991-2001

12 7.3 3.1 4.2

9 34.7 15.3 25.6

12 635 277 403

12 24,400 15,100 19,700

12 115 49 77

12 2,270 671 1,210

9 19.1 9.3 14.2

12 3.9 <1.9 '2.2

12 1,160 775 915

12340000--BLACKFOOT RIVER NEAR BONNER. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1991, 1993-96, 1998-2001

11 2.0 <.2 '.6

8 25.8 15.1 20.5

11 27 16 21

11 20,200 12,400 17,000

11 20 <13 '13

11 683 298 524

8 14.3 9.4 12.2

11 1.0 <.3 '.4

11 73 35 60

12340500--CLARK FORK ABOVE MISSOULA. MONT.

Period of record for fine-grained bed-sediment data: 1997-2001

5 4.2 1.5 2.8

5 30.6 19.0 25.8

5 516 166 283

5 24,300 18,100 20.800

5 63 37 51

5 1,370 480 1,010

5 15.8 11.8 13.8

5 2.9 .8 'l.8

5 924 438 623

Median

'<.4

21.4

14

18,000

'9

382

12.9

'<.3

48

39

27.7

354

19,600

72

1.110

15.9

'2.2

894

'<1.2

21.8

21

17,800

'13

535

12.6

'.3

61

2.6

28.5

233

20.400

47

1,160

14.5

'1.6

547

76 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 September 2001 (Continued)

_, . Number of Constituent samples

Maximum

Minimum Mean Median

12353000-CLARK FORK BELOW M1SSOULA. MONT.2

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Period of record for fine-grained

13

9

13

13

13

13

9

13

13

bed-sediment data: 1986,

6.0

27.6

293

21,100

58

2,530

14.1

3.0

675

1.1

12.3

87

13,400

12

446

8.9

.4

252

1990-2001

2.1

21.7

152

18.400

37

1,330

12.5

'1.3

405

1.9

21.5

138

19,500

37

1,260

12.8

'1.3

409

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. 

2Samples collected about 30 miles downstream from streamflow-gaging station to conform to previous sampling location.

TABLE 22 77
Table 23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, 

August 1993 through September 2001

[Bulk bed sediment is material smaller than about 10 millimeters in diameter. Reported concentrations are in micrograms per gram 

dry weight. Symbols: <, less than minimum reporting level; , indicates 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]

Number of Constituent samplesMaximum

Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY MONT.

Period of record for bulk bed-sediment data:

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

8

8

8

8

8

8

8

8

8

22.2

16.2

2,780

29,300

363

5,480

9.2

7.4

5,690

1993-95, 1997-2001

4.2

9.6

670

18,300

198

504

6.0

3.2

1,720

10.7

12.9

1,270

22,600

263

1,640

7.3

4.7

2,970

7.6

12.4

939

20,200

255

747

6.7

4.0

2,160

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.

Period of record for bulk bed-sediment data: 1993, 1995-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

8

8

8

8

8

8

8

8

8

1.7

11.8

111

12,300

33

2,100

9.2

1.3

303

<.9

5.3

20

7,200

<10

209

4.8

<.3

93

'1.1

9.1

51

10,100

'14

874

6.2

'.7

160

'1.3

9.5

37

9,800

'12

776

5.5

'.8

134

12327700--WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

Period of record for bulk bed-sediment data

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

3

3

3

3

3

3

3

3

3

1.0

12.0

238

12,700

38

2,650

8.5

1.1

275

12323800--CLARK FORK NEAR GAI

: 1995, 1997, 1999

<.8

9.7

203

8,980

18

1,220

5.7

<.8

146

.EN. MONT.

'.6

11.2

215

10,900

30

2.100

7.3

'.8

190

'<.9

11.8

205

10,900

34

2,440

7.8

'.9

148

Period of record for bulk bed-sediment data: 1993-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

9

9

9

9

9

9

9

9

9

8.2

23.7

902

31,300

158

9.490

15.2

5.2

1,280

<.9

4.2

223

9,930

41

900

4.9

.7

417

'3.7

15.0

470

20,500

80

3,370

8.7

'2.0

721

'3.5

15.0

408

20,600

79

1,880

8.8

'1.6

653

78 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 September 2001 (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

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

Period of record for bulk bed-sediment data: 1996-2001

6 3.3 <.9 '2.4

6 17.5 9.3 12.5

6 763 238 460

6 21.000 12,600 17,100

6 104 41 74

6 1,840 1,260 1,490

6 8.2 42 6.5

6 2.8 .8 '1.7

6 787 365 554

461559112443301-CLARK FORK NEAR RACETRACK. MONT.

Period of record for bulk bed-sediment data: 1996-2001

6 6.6 <.9 '2.8

6 19.1 10.1 14.2

6 603 361 475

6 25,900 16,200 19,300

6 87 59 75

6 1,710 759 1,320

6 9.9 5.5 7.3

6 2.9 1.4 '2.2

6 781 472 616

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

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

Period of record for bulk bed-sediment data: 1996-2001

6 9.2 1.5 3.7

6 21.1 13.0 17.1

6 1,000 244 530

6 25,400 16,400 21,900

6 115 47 76

6 4,930 825 1.930

6 12.8 5.5 8.6

6 4.4 <.8 '2.4

6 1,240 368 651

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for bulk bed-sediment data: 1993-2001

9 7.8 1.0 '2.7

9 24.5 12.1 18.0

9 906 281 471

9 25,000 13.200 19,200

9 112 45 75

9 2,530 653 1,200

9 12.3 7.7 9.8

9 3.9 <.7 '1.7

9 1,060 456 613

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

Period of record for bulk bed-sediment data: 1994, 1998, 2001

3 <1.5 <1.2 '.7

3 33.2 14.7 26.7

3 20 12 17

3 21,000 15,600 18,000

3 18 12 15

3 420 308 354

3 15.2 8.6 11.8

3 <1.6 <.7 '.6

3 86 65 75

Median

'2.8

12.1

426

16,700

75

1,420

6-8

'1.6

560

'2.4

13.7

458

18,200

77

1,390

6.9

'2.3

584

MONT.

3.0

16.8

501

22.200

73

1.490

8.2

'2.4

526

'2.1

19.6

383

19,200

74

1020

10.1

'1.6

529

'.7

32.1

19

17,300

14

333

11.7

'.8

73

TABLE 23 79
Table 23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, 

August 1993 through September 2001 (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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

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

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for bulk bed-sediment data: 1993-2001

9 7.6 1.1

9 33.2 15.0

9 858 197

9 24,900 15,400

9 92 37

9 2,930 554

9 15.9 9.0

9 3.7 <.7

9 1,020 368

12331500--FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-2001

9 3.8 <.2

9 13.9 4.9

9 40 16

9 15700 8,630

9 120 51

9 3,200 1,150

9 8.0 4.5

9 5.8 2.5

9 429 178

12331800-CLARK FORK NEAR DRUMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-2001

9 4.7 <1.6

9 29.5 6.9

9 605 114

9 21,800 12,100

9 78 32

9 1,510 656

9 14.2 7.8

9 3.5 .5

9 939 397

12334510-ROCK CREEK NEAR CLINTON. MONT.

Period of record for bulk bed-sediment data: 1993-99, 2001

8 <1.5 <.2

8 

873

14.3 6.4

8 11,100 5,290

8 <13 <3

8 270 72

8 8.2 3.6

8 <1.6 .1

8 29 7

12334550-CLARK FORK AT TURAH BRIDGE. NEAR BONNER.

Period of record for bulk bed-sediment data: 1993-2001

9 49 .4

9 23.8 6.9

9 336 75

9 19.100 9.270

9 67 21

9 1.470 234

9 14.0 6.4

9 2.9 <.3

9 769 271

Mean

"3.3

22.2

462

19,200

65

1,360

11.8

'1.9

708

'1.6

9.4

24

12,800

76

2,110

5.8

4.3

277

'2.4

19.0

275

16,200

49

1,050

10.6

'l.7

598

i

9.0

5

7,930

'5

160

5.3

'.4

17

MONT.

'2.0

15.1

190

13,300

38

680

9.2

'1.2

479

Median

"2.4

21.1

370

18,600

71

1,190

12.0

'1.6

676

'1.5

10.7

20

13,400

79

2,190

5.8

4.1

284

'1.8

17.5

223

15,900

47

980

9.8

'1.6

515

"<.8

8.5

5

7,340

'5

166

5.0

'.3

17

"1.8

15.5

186

13,200

37

487

8.8

'.9

501

80 Water-qnality, bed-sediment, and biological data (October 2000 through September 2001) 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 September 2001 (Continued)

Constituent Number of 

samples

Maximum

Minimum Mean Median

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

12340000-BLACKFOOT RIVER NEAR BONNER. MONT. 

Period of record for bulk bed-sediment data: 1993-94,1999-2001

19.2 6.7

19 12

17,000

11

650

9.8 

<1.9 

58

10,300 

6

179 

7.5 

<.4 

33

13.0

16

14,000

9

340

8.8 

I

41

12.5 

16

14,600 

10 

305 

9.3 

'<.7 

35

12340500-CLARK FORK ABOVE MISSOULA. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Period of record for bulk

5

5

5

5

5

5

5

5

5

bed-sediment data:

3.4

18.2

130

16,800 11

30

810

11.1

<3.3

387

1997-2001

<.8

9.7

43

,500

7

228

8.2

<.4

145

"1.2 

14.0 

87

14,900 

21 

510 

9.6 

'.8 

270

'.8 

15.0 

72

16,020 

20 

553 

9.2 

'.8 

263

12353000-CLARK FORK BELOW MISSOULA. MONT/ 

Period of record for bulk bed-sediment data: 1993-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

9

9

9

9

9

9

9

9

9

2.0

12.6

77

11.300

19

444

7.1

<1.9

172

<.2

4.4

16

5.830

<10

150

3.5

<.3

58

'.7

7.1

37

8,480

'9

326

5.1

'.5

110

'.6

6.8

30

8,830

'8

364

4.9

'.5

101

'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.

2Samples collected about 30 miles downstream from streamflow-gaging station to conform to previous sampling location.

TABLE 23 81
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

September 2001

[Concentrations are in micrograms per gram dry weight. Abbreviation: spp., species. 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 morose group are based on the combined results for two 

or more species. Insects were depurated prior to analysis during 1986-98, depuration was discontinued in 1999]

Constituent

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of

composite Maximum Minimum

samples

12323600--SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for biological data: 1992, 1994-95. 1997-2001

Brachvcentrus SPP.

4 12.5 5.8

4 5.9 .7

4 846 235

4 730 335

4 17.9 7.4

4 666 231

4 1.9 <.l

4 888 629

Hvdroosvche cockereltt

5 6.3 4.1

5 8.0 1.0

5 462 269

5 1,180 689

5 21.7 19.0

5 718 180

5 2.1 .7

5 898 749

Hvdroosvche spp.

3 10.6 5.0

3 4.7 .8

3 884 352

3 1,750 1,270

3 50.8 34.7

3 1,070 712

3 2.5 1.6

3 1,290 1,090

Hvdroosvche tana

6 9.2 4.8

6 11.5 .9

6 456 J0.5

6 1.520 857

6 21.0 15.6

6 969 307

6 1.8 .7

6 1,070 760

12323750--SILVER BOW CREEK AT WARM SPRINGS. MONT

Period of record for biological data: 1992-2001

Hvdroosvche cockerelli

24 2.1 .2

24 1.3 .5

24 97.0 22.4

24 1.240 351

24 5.7 .3

24 2,520 491

24 1.8 .3

24 276 115

Mean

9.6

2.1

565

474

11.7

439"1.2

755

4.9

3.7

365

931

20.3

460

1.4

818

8.7

2.3

693

1,480

40.6

941

2.1

1,170

6.8

4.5

236

1,100

18.6

634

1.4

961

.7

.8

43.0

683

3.1

1,080

.8

180

Median

10.0

.9

589

416

10.8

430

'1.3

751

4.7

3.1

333

953

20.1

434

1.6

805

10.2

1.5

845

1,430

36.5

1,040

2.2

1,130

6.9

1.8

298

1,050

18.3

675

1.6

1,020

.6

.8

40.6

717

2.9

839

.8

171

82 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 

September 2001 (Continued)

Number of

Constituent composite Maximum Minimum

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

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: 1992-2001

Hvdropsvche occidentalis

13 1.1 .2

13 1.7 .3

13 46.5 11.0

13 1.050 372

13 4.3 <1.7

13 3.200 1.200

13 1.8 .7

13 202 141

Hvdropsvche 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

12323770--WARM SPRINGS CREEK AT WARM SPRINGS.

Period of record for biological data: 1995, 1997, 1999

Arctoosvche erandis

3 2.4 1.9

3 2.9 1.4

3 102 95.6

3 1,040 684

3 5.6 <6.3

3 2,280 1,340

3 <7.0 1.8

3 222 180

Hvdropsvche occidentalis

2 .8 .7

2 3.2 3.2

2 183 181

2 2,070 1,950

2 8.2 6.7

2 2,480 2,400

2 3.3 3.0

2 172 166

Hvdropsvche SPP.

1

i

__

_.

__

--

12323800-CLARK FORK NEAR GALEN. MONT.

Period of record for biological data: 1987, 1991-2001

Hvdroosvche cockerelli

22 2.7 .9

22 3.3 .8

22 181 48.7

22 2,460 816

22 11.7 1.2

22 3,620 1,070

22 3.1 .9

22 299 136

.5

.9

30.6

806

'3.1

2,090

1.2

173

1.1

.8

40.9

680

2.9

725

'.8

195

MONT.

2.2

2.0

98.9

866

'4.4

1,810'2.5

200

.8

3.2

182

2.010

7.4

2,440

3.2

169

<9.3

1.6

94.8

1,150

<16.7

956

2.0

129

1.6

1.7

100

1,390

7.6

2,190

1.6

218

.4

9

30.3

774

'3.1

1,840

1.1

175

.9

1.2

40.6

693

4.7

678'.5

177

2.1

1.8

98.8

872

<8.7

1,800

2.3

197

-

-

-

-

-

-

-

-

-

-

-

1.5

1.6

99

1,280

7.7

2,180

1.6

215

TABLE 24 83
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

September 2001 (Continued)

Number of

Constituent composite

samples

Maximum Minimum Mean Median

12323800-CLARK FORK NEAR GALEN. MONT.-Continued

Period of record for biological data: 1987, 1991-2001

Hvdropsvche morosa group

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

5

5

5

5

5

5

5

5

3.2

4.6

185

1,890

12.4

3,960

3.6

349

2.4

1.8

156

1.360

7.1

2,360

1.9

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

Hvdroosvche occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

31

31

31

31

31

31

31

31

1.7

6.6

106

1,920

13.5

6,170

3.5

286

.6

.7

49.2

642

1.6

1,220

.8

168

1.1

1.8

78.3

1,210

6.7

2,640

1.6

202

1.1

1.5

75.5

1.180

6.3

2,280

1.6

197

Hvdroosvche tana

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

-

-

-

-

-

-

-

-

--

1.5

1.4

92.9

1,340

9.0

?,160

2.1

206

-

-

-

-

-

Hydroosvche spp.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

4

0

4

4

4

0

0

4

3.5

154

1,540

13.5

-

-

329

2.6

135

1,190

10.5

-

-

279

3.0

148

1,400

12.2

-

-

308

3.0

152

1,450

12.4

-

-

313

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

Period of record for biological data: 1996-2001

Claassenia sabulosa

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

-

-

-

-

-

-

-

-

.3

19

70.1

189

1.2

238

.2

245

-

-

-

Hvdropsvche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

9

9

9

9

9

9

9

9

2.8

2.6

147

1,900

14.8

3.160

1.9

250

1.4

1.0

48.8

691

4.5

1,230

1.0

151

2.1

2.0

108

1,340

10.8

2,050

1.4

221

2.2

2.1

98.2

1,300

11.3

1,720

1.4

234

84 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 

September 2001 (Continued}

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

461415112450801-CLARK FORK BELOW LOST CREEK. NEAR GALEN.

Period of record for biological data: 1996-2001

Hvdroosvche occidentalis

14 1.8 .9

14 3.3 1.3

14 157 52.1 

14 1.920 963

14 12.4 6.6

14 3,440 1,270 

14 1.7 .9

14 283 174

Hvdropsvche SPP.

4 1.8 1.2

4 2.4 .9

4 122 45.1 

4 1,410 533

4 20.5 4.1

4 1,980 799 

4 2.8 1.4

4 225 143

MONT.-Continued

1.3

1.9

102 

1.400

9.7

2,280 

1.3

230

1.4

1.6

89.0 

1,120

10.4

1,490 

1.9

183

1.6

1.9

120 

1,520

11.5

1,850 

1.5

231

1.4

1.6

94.3 

1,270

8.5

1,590 

1.4

183

461559112443301-CLARK FORK NEAR RACETRACK. 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: 1996-2001

Claassenia sabulosa

-

__

-

__

H\drops\che cockerelli

10 1.9 1.0

10 2.7 .7

10 109 50.0 

10 1,370 657

10 10.5 3.7

10 2,010 646 

10 1.4 .7

10 199 139

Hvdropsvche occidentolis

13 2.2 .7

13 2.6 1.1

13 160 59.5 

13 1,880 1,030

13 11.7 4.3

13 3,770 1,090 

13 1.9 1.1

13 255 181

Hvdropsvche spp.

2 1.5 1.0

2 1.7 .7

2 85.2 82.9 

2 1,200 1,140

2 7.4 5.7

2 1,600 910 

2 1.4 1.1

2 208 151

.4

.3

40.3 

113

.8

172 

.2

213

1.4

1.5

74.1 

938

6.6

1,440 

1.0

172

1.3

1.9

102 

1,470

9.4

2,160 

1.3

226

1.2

1.2

84.0 

1,170

6.6

1,260 

1.2

180

-

-

-

-

1.3

1.3

67.4 

921

6.1

1,610 

1.1

172

1.2

1.8

93.5 

1,450

9.7

2,100 

1.3

229

-

-

-

TABLE 24 85
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana. August 1986 through 

September 2001 (Continued)

Constituent

461903112440701--CI

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of 

composite Maximum Minimum 

samples

,ARK FORK AT DEMPSEY CREEK DIVERSION. NEAR

Period of record for biological data: 1996-2001

Arctopsvche erandis

__

__

__

..

Hvdroosvche cockerelli

1 1.6 .7

7 1.7 .8

7 143 62.7

7 1,290 665

7 8.9 3.5

7 1,230 487

7 1.9 .6

7 192 162

Hvdropsvche occidentalis

16 1.7 .7

16 2.8 1.2

16 163 74.9

16 1,660 940

16 13.8 6.1

16 3,990 826

L6 2.4 1.2

16 292 222

Hvdroosvche 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

2 212 L91

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for biological data: 1986-87, 1990-2001

Arctopsvche 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

Hvdropsvche cockerelli

22 2.3 .6

22 3.2 .4

22 136 54.7

22 3,340 490

22 18.2 4.3

22 1.490 396

22 2.4 .3

22 391 132

Mean

RACETRACK.

1.7

<2.4

30.8

340

<14.5

510

1.0

87

1.2

1.1

84.6

888

6.2

1,010

1.1

177

1.1

1.9

95.8

1,440

11.1

2,490

1.5

247

1.6

1.8

122

1,340

11.8

892

1.6

202

'2.2

'.8

52.0

606

'3.8

554

l__

159

1.4

1.7

93.4

1,160

9.6

811

1.2

186

Median

MONT.

-

-

-

-

1.4

1.0

77.5

851

6.8

1,140

.9

178

1.1

1.8

88.3

1,500

11.4

2,310

1.4

236

-

-

-

__

-

1.3

1.8

92.5

1,050

8.9

710

1.0

184

86 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 

September 2001 (Continued)

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

Period of record for biological data: 1986-87, 1990-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Hvdroosvche occidentalis

36 2.7

36 3.6

36 162

36 2,060

36 18.6

36 2,840

36 12.9

36 329

Hvdropsvche SPP.

3 2.0

0

3 222

3 2,220

3 15.0

0

0

3 203

.8

.6

49.4

557

3.5

649

1.0

166

1.2

103

1,110

5.6

-

185

1.3

1.9

112

1,410

11.0

1.710

1.8

238

1.6

145

1,520

8.8

-

-

195

1.3

1.9

110

1,420

10.8

1,730

1.4

233

1.6

Ill

1,240

5.7

-

-

197

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. 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: 1987,

Arctopsvche srandis

15 .7

15 1.6

15 14.2

15 677

15 1.3

15 1.140

15 1.4

15 214

Cld&ssenici sobuloso. i ~

7 .9

7 36.1

7 319

7 <.8

7 90.5

7 .7

7 233

H\drops\che cockerelli

1

1

1

1

1

1

1

1

Hvdronsvche occidentalis

1 <.l

2 2.3

2 15.2

2 1,340

2 2.3

2 554

2 1.1

2 137

1994,1998,2001

.2

.6

9.0

177

.5

318

.4

113

.1

.3

20.0

98

<.l

46.7

.4

172

-

-

-

-

-

.3

1.3

15.1

426

<3.7

434

.8

110

.4

.9

12.2

384

.8

678

.7

165

.2

.6

29.4

175

U

63.8

.5

203

.6

1.6

28.4

478

3.6

399

1.2

123

'.3

1.8

15.2

883

'2.1

494

1.0

124

.4

.8

13.0

313

.8

551

.6

162

.2

.7

30.3

156

'.3

61.6

.5

202

-

-

-

-

--

-

-

-

-

-

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

September 2001 (Continued)

Constituent

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of 

composite Maximum Minimum 

samples

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for biological data: 1992-2001

Arctopsvche prandis

25 6.6 1.1

25 3.3 .6

25 129 26.4

25 2,360 339

25 10.9 2.3

25 1.580 592

25 1.8 .2

25 326 165

Claassenia sabulosa

18 3.5 .3

18 1.6 .3

18 81.7 33.0

18 567 63.0

18 1.8 .5

18 279 50.6

18 .7 .2

18 351 166

Hvdronsvche cockereUi

17 2.6 .6

17 4.7 .5

17 188 17.1

17 3,250 522

17 16.2 2.4

17 1,670 538

17 2.3 .3

17 249 106

Hvdroosvche 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

Hvdroosvche occidentalis

15 1.7 .7

15 3.9 .4

15 156 26.4

15 2.720 466

15 15.7 2.9

15 2,210 530

15 2.5 .8

15 277 97

12331500-FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for biological data: 1986, 1992-2001

Arctopsvche erandis

38 .8 .1

38 4.7 .3

38 21.7 8.9

38 2,460 412

38 17.5 3.7

38 2,480 424

38 2.7 .6

38 275 93

Mean

2.6

1.4

53.2

817

4.4

876

.8

220

1.4

.6

56.0

190

1.1

117

.3

255

1.6

2.3

83.0

1,320

8.0

792

1.3

192

1.4

1.4

60.5

1,050

4.6

804

1.2

167

1.3

1.6

64.4

1,140

7.3

1,170

1.3

195

.3

1.9

14.9

1.350

9.0

1,480

1.4

196

Median

2.3

1.1

51.3

610

3.7

842

.7

200

1.0

.6

55.9

174

1.1

94.7

.3

258

1.6

2.0

66.6

1,080

6.0

687

1.3

201

1.4

1.4

62.7

1,130

4.6

822

1.2

170

1.3

1.6

58.3

1,040

6.0

1,030

1.1

192

.3

1.7

15.1

1.320

8.1

1,340

1.3

190

88 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 

September 2001 (Continued)

12331500-FLINT CREEK NEAR DRUMMOND. MONT.-Continued

Period of record for biological data: 1986, 1992-2001

Hvdroosvche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

10

10

10

10

10

10

10

10

.7

4.0

28.3

3,390

28.4

2,460

2.3

208

.1

.9

9.5

996

3.1

401

.9

85

.4

2.0

18.2

1,990

13.9

1.210

1.9

167

.3

1.9

18.1

1,950

14.6

1,210

2.2

181

Hvdroosvche occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

7

7

7

7

7

7

7

7

1

I

2

2

2

2

2

2

2

2

1.1

17.6

27.3

2,990

29.8

4,790

6.9

243

Hvdropsvche sop.

-

H\droos\che tana

<1.2

10.3

16.0

1,320

15.3

1,400

3.1

139

.2

.7

15.1

912

5.8

1,400

.8

128

-

<.l

.6

5.4

729

5.0

1,180

.5

107

.6

4.5

20.6

1,900

19.4

2,270

3.0

185

<3

1.4

12.5

1,440

4.5

1,320

1.3

130

l

5.4

10.7

1.020

10.2

1,290

1.8

123

.6

2.1

18.6

1,870

24.0

1,780

2.4

188

-

-

-

-

-

--

12331800-CLARK FORK NEAR DRUMMOND. MONT.

Period of record for biological data: 1986,

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

29

29

29

29

29

29

29

29

34

34

34

34

34

34

34

34

Arctopsvche erandis

3.8

2.5

89.2

1,660

11.8

2,010

1.9

308

Clficisscn id sdbulosct

2.8

3.3

165

387

2.9

410

1.1

567

1991-2001

.5

.2

17.3

240

2.1

462

.2

142

.2

.3

18.0

45.4

.2

33.1

.1

103

1.6

1.0

36.1

642

4.9

892

.7

197

1.2

.8

65.7

162

1.0

161

.3

273

1.4

1.0

29.6

576

4.3

754

.7

190

1.2

.6

538

135

.8

135

.2

251

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

September 2001 (Continued)

Number of 

Constituent composite Maximum 

samples

12331800-CLARK FORK NEAR DRUMMOND

Minimum Mean Median

. MONT.-Continued

Period of record for biological data: 1986, 1991-2001

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

Hvdroosvche cockerelli

26 2.3

26 3.5

26 156

26 2,500

26 15.0

26 1.680

26 2.0

26 248

Hvdroosvche morosa group

6 1.3

6 2.8

6 57.4

6 1,730

6 10.8

6 1,940

6 1.7

6 250

Hvdroosvche occidentalis

16 2.0

16 8.1

16 118

16 2,060

16 14.0

16 2,920

16 2.4

16 293

H\drops\che SDP.

1

0

1

1

1

0

0

1

.6

.4

30.0

506

5.1

549

.5

134

1.1

1.9

50.2

1,380

7.0

1,260

1.3

227

.7

.4

13.3

424

2.9

619

.5

157

-

-

-

-

1.3

1.7

64.3

1,240

9.1

947

1.2

197

1.2

2.3

55.2

1,570

8.9

1.610

1.5

239

1.2

2.4

55.8

1,280

9.4

1,560

1.5

226

2.6

85.0

940

9.1

-

260

1.2

1.6

52.6

1,030

8.6

849

1.2

191

1.2

2.2

55.8

1,600

9.0

1,620

1.5

240

1.2

2.1

55.7

1,310

9.5

1,220

1.6

225

-

-

-

-

-

12334S10-ROCK CREEK NEAR CLINTON. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1987,

Arctopsvche erandls

36 .4

36 2.9

36 15.7

36 1,040

36 1.1

36 454

36 1.7

36 189

Claassenia sabulosa

18 .3

18 1.8

18 40.7

18 129

18 1.0

18 76.3

18 .9

18 264

1991-99, 2001

.06

.5

4.7

191

.1

113

.2

84

.05

.1

18.1

49.8

.1

15.7

.1

144

.2

1.2

8.7

568

'.4

256

.9

129

.2

.7

29.0

92.2

.4

34.7

.3

199

.2

1.0

8.5

524

'.4

239

1.0

134

.2

.6

28.9

98.7

.3

33.6

.3

198

90 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 

September 2001 (Continued)

Number of

Constituent composite Maximum

samples

Minimum Mean Median

12334510-ROCK CREEK NEAR CLINTON. 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

Period of record for biological data: 1987,

Hvdropsvche cockerelli

3 <.2

3 1.0

3 13.1

3 609

3 <1.1

3 258

3 .9

3 99

Hvdronsvche occidentalis

4 <1.0

4 2.4

4 17.6

4 752

4 6.0

4 268

4 1.7

4 144

Hvdropsvche son.

3 .3

3 2.1

3 16.2

3 1,140

3 <3.1

3 462

3 1.3

3 135

1991-99, 2001

<.2

.9

6.0

485

<1.1

192

.4

82

<.3

.9

9.6

520

1.2

169

.6

99

<.5

1.1

11.6

837

<1.8

299

.8

117

12334550-CLARK FORK AT TURAH BRIDGE. NEAR BONNER.

l__

.9

8.6

530

l__

219

.6

89

I _

1.6

12.0

642

3.0

228

1.2

121

'.2

1.6

14.3

1,000

I

399

1.1

126

MONT.

<.2

.9

6.6

497

<1.1

208

.4

86

<.3

.9

10.2

648

1.2

215

.9

117

.2

1.7

15.0

1,030

<2.9

437

1.1

126

Period of record for biological data: 1986, 1991-2001

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arctoosvche erantKs

40 2.7

40 4.1

40 125

40 2,870

40 13.2

40 893

40 2.7

40 276

Claassenia sabulosa

25 2.5

25 2.0

25 79.2

25 181

25 1.6

25 139

25 .6

25 283

Hvdropsvche cockerelli

26 1.7

26 8.0

26 118

26 2,530

26 12.1

26 788

26 2.6

26 228

.6

.6

20.1

420

2.1

351

.4

152

.3

.2

38.3

58.6

.2

37.2

.1

144

.5

1.0

26.4

688

2.2

426

.6

148

1.3

1.7

41.0

1,050

4.8

643

1.2

204

1.1

.7

56.1

105

.6

75.6

.2

220

.9

2.1

50.7

1,290

5.6

606

1.3

189

1.1

1.6

34.1

908

4.4

652

1.0

199

.9

.6

53.4

102

.6

67.4

.2

222

.7

1.7

44.1

1,160

5.4

580

1.2

184

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

September 2001 (Continued)

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

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

Period of record for biological data: 1986, 1991-2001

Hvdropsvche morosa group

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

2

2

2

2

2

2

2

2

1.3

4.6

84.1

1,800

66

1,320

1.7

231

1.1

2.4

26.8

986

<7.8

537

1.3

171

1.2

3.5

55.4

1,390

5.2

928

1.5

201

-

-

-

-

--

-

-

Hvdropsvche occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

19

19

19

19

19

19

19

19

1

1

1.8

3.2

102

2,310

14.2

1.600

3.2

416

Hvdropsvche sop.

-

-

-

-

.3

.6

34.1

472

3.0

454

.6

145

-

-

-

.9

1.9

50.9

1,220

6.8

822

1.3

208

1.3

2.4

84.1

1.800

<7.8

537

1.3

171

.9

1.7

44.9

1,120

5.7

697

1.0

189

-

-

-

-

12340000--BLACKFOOT RIVER NEAR BONNER. MONT.

Period of record for biological data: 1986-87, 1991,

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

10

4

10

10

10

4

4

10

11

5

11

11

11

5

5

11

Arctopsvche erandis

.4

1.8

134

1,230

2.1

517

1.2

143

Claassenia sabulosa

.2

.9

88.5

199

.6

127

.3

329

1993, 1996,

<.l

.8

9.9

108

.5

286

.8

123

.1

.3

19.0

46.2

.4

26.3

.1

117

1998, 2000

'.2

1.3

11.9

588

1.1

398

1.0

135

.1

.5

45.2

100

.3

57.1

.2

209

'.2

1.2

12.0

609

.8

393

.9

136

.1

.5

44.0

99.0

.4

44.7

.2

194

Hvdroasvche occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

12

12

12

12

12

12

12

12

.5

2.7

20.6

1.930

1.9

527

1.8

150

.1

.8

12.0

1,060

.8

414

.9

117

.2

1 8

14.6

1,410

1.3

472

1.3

134

.2

1.7

14.4

1,380

1.2

460

1.2

130

92 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) 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 

September 2001 (Continued)

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

12340000--BLACKFOOT RIVER NEAR BONNER L MQNT.-Continued

Period of record for biological data: 1986-87, 1991, 1993, 1996, 1998, 2000

Hvdroosvche SPP. 

.6

- -

1.6

13.9 

1,140

2.9

525 

2.8

132

--

--

12340500--CLARK FORK ABOVE MISSOULA. MONT.

Period of record for biological data: 1997-2001

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

Arctopsvche erandis

16 1.8

16 3.0

16 77.6 

16 2,340

16 6.8

16 1,210 

16 2.0

16 235

Claassenia sabulosa

7 2.0

7 1.1

7 71.7 

7 402 

7 3.1

7 683 

7 <1.3

7 363

Hvdronsvche cockerelli

9 1.3

9 4.1

9 96.1 

9 3,590

9 6.3

9 1.470 

9 2.4

9 226

Hydfopsyche occidentcilis

6 1.1

6 3.2

6 76.5 

6 2,400 

6 7.7

6 2,460 

6 2.3

6 232

.5

.8

22.3 

476

1.2

476 

.7

133

.2

.4

37.8 

95.0 

.5

75.2 

<.3

191

.4

1.8

29.9 

1.400

4.2

781 

1.4

156

.4

2.1

30.3 

1,450 

4.0

939 

1.6

192

.8

1.5

33.9 

1,030

3.2

845 

1.1

178

.9

.8

50.5 

225 

'1.2

254 

'.4

273

.8

2.8

56.3 

2,120

5.4

1,050 

1.8

189

.7

2.7

48.5 

1,970 

5.7

1,810 

2.0

218

.7

1.5

28.2 

947

2.9

887 

1.0

175

.6

.7

46.8 

229 1.0

136 

'.4

273

1.0

3.1

45.7 

2,040

5.5

1,000 

1.6

191

.7

2.9

48.2 

2,110 

5.5

1,810 

2.0

221

12353000-CLARK FORK BELOW MISSOULA. MONT.2

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Period of record for biological data: 1986,

Arctopsvche erandis

23 1.5

23 2.7

23 38.0 

23 1,500

23 3.2

23 1,090 

23 1.6

23 217

1990-2001

.2

.5

9.4

343

.9

511

.4

106

.7

1.3

21.2 

781

1.8

729 

.9

154

.6

1.4

20.3 

754

1.8

715 

.9

148

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

September 2001 (Continued)

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

12353000-CLARK FORK BELOW MISSOULA. MONT.2-Continued

Period of record for biological data: 1986,1990-2001

Claassenia sabulosa

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

36

36

36

36

36

36

36

36

34

34

34

34

34

34

34

34

1

16

16

16

16

16

16

16

16

1.3

1.2

74.8

240

1.3

168

.3

286

Hvdropsvche cockerelli

1.1

3.4

45.7

2,000

3.6

1,210

1.7

172

Hvdroosvche occidentalis

1.1

3.5

38.2

1,420

4.2

1,460

2.2

193

Hvdropsvche spp.

-

-

-

-

-

.1

.05

31.1

66.6

.1

48.9

.1

146

.2

.8

12.4

584

1.2

353

.5

77.4

.2

.1

16.0

482

.7

491

.5

112

-

-

-

-

-

-

.5

.5

48.1

110

.4

104

.2

214

.5

1.9

28.9

1,280

2.3

760

1.2

144

.5

1.4

24.4

956

2.1

849

1.0

144

.5

.8

208

894

1.1

756

1.1

124

.4

.5

46.7

98

.3

101

.2

204

.6

1.9

28.3

1.320

2.4

673

1.3

147

.4

1.5

21.6

985

1.9

825

.9

147

-

-

-

'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 and 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 streamflow-gaging station to conform to previous sampling location.

94 Water-quality, bed-sediment, and biological data (October 2000 through September 2001) and statistical summaries of data for streams in the 

upper Clark Fork Basin, Montana

 d U.S. GOVERNMENT PRINTING OFFICE: 2002 573-099 / 66005 Region No. 8