In cooperation with the

U.S. ENVIRONMENTAL PROTECTION AGENCY

Water-Quality, Bed-Sediment, and Biological 

Data (October 2001 through September 2002) 

and Statistical Summaries of Data for Streams 

in the Upper Clark Fork Basin, Montana

Open-File Report 03-356

U.S. Department of the Interior 

U.S. Geological Survey

In cooperation with the

U.S. ENVIRONMENTAL PROTECTION AGENCY

Water-Quality, Bed-Sediment, and Biological 

Data (October 2001 through September 2002) 

and Statistical Summaries of Data for Streams in 

the Upper Clark Fork Basin, Montana

By Kent A. Dodge, Michelle I. Hornberger, and 

Irene R. Lavigne

Open-File Report 03-356

U.S. Department of the Interior 

U.S. Geological Survey

Helena, Montana 

September 2003
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 2001 through September 2002........ 17

5-7. Daily streamflow and suspended-sediment data, October 2001 through September 2002, for:

5. Clark Fork at Deer Lodge, Montana..................................................................................................... 33

6. Clark Fork at Turah Bridge, nearBonner, Montana............................................................................. 37

7. Clark Fork above Missoula, Montana .................................................................................................. 41

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

basin, Montana............................................................................................................................................ 45

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

Clark Fork basin, Montana......................................................................................................................... 46

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

Montana...................................................................................................................................................... 47

11. Recovery efficiency for trace-element analyses of laboratory-spiked deionized-water blanks..................... 48

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

Fork basin, Montana................................................................................................................................... 49

13. Chemical analyses of field blanks for water samples.................................................................................... 50

14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, August 2002..... 51

15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, August 2002.................. 52

16. Recovery efficiency for trace-element analyses of standard reference materials for bed sediment.............. 53

17. Trace-element analyses of procedural blanks for bed sediment.................................................................... 54

CONTENTS iii
TABLES (Continued)

Page 

Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 2002 ...................................... 55

19. Recovery efficiency for trace-element analyses of standard reference material for biota............................ 57

20. Trace-element analyses of procedural blanks for biota................................................................................. 58

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

through September 2002 ............................................................................................................................ 59

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

August 1986 through August 2002 ............................................................................................................ 74

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

1993 through August 2002......................................................................................................................... 79

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

through August 2002.................................................................................................................................. 83

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

_______________________________Multiply________________By_______________To obtain__________________

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

foot (ft) 0.3048 meter (m)

gallon (gal) 3.785 liter (L)

gallon (gal) 3,785 milliliter (mL)

inch (in.) 25.4 millimeter (mm)

inch (in.) 25,400 micrometer (|im)

mile (mi) 1.609 kilometer

ounce (oz) 28.35 gram (g)

part per million 1 microgram per gram (|ig/g)

square mile (mi ) 2.59 square kilometer 

___________________ton per day (ton/d)_____________ 907.2_________kilogram per day_______________________________

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

°F = 9/5 (°C) + 32

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:

|o,g/g micrograms per gram

M-g/L micrograms per liter

Ug/mL micrograms per milliliter

|o,m micrometer

|o,S/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 2001 through September 2002) and statistical summaries of data for streams in the 

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

2001 through September 2002) and Statistical Summaries of 

Data for Streams in the Upper Clark Fork Basin, Montana

By Kent A. Dodge, Michelle I. Hornberger1 , and Irene R. Lavigne 1

Abstract

Water, bed sediment, and biota were sampled in 

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

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

15 stations during October 2001 through September 

2002 (water year 2002). Data for 15 bed-sediment and 

15 biological stations were obtained in August 2002. 

The primary constituents analyzed were trace elements 

associated with tailings from historical mining and 

smelting activities.

Water-quality data include concentrations of 

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

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

the fine-grained and bulk fractions. Biological data 

include trace-element concentrations in whole-body 

tissue of aquatic benthic insects. Quality-assurance 

data are reported for analytical results of water, bed 

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

for the period of record at each station since 1985.

INTRODUCTION

The Clark Fork originates near Warm Springs in 

western Montana at the confluence of Silver Bow and 

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

of stream from Silver Bow Creek in Butte to the Clark 

Fork at Milltown Reservoir, six major tributaries enter: 

Blacktail Creek, Warm Springs Creek, Little Blackfoot 

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

ry

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 elevated trace-element concentrations in water and bed sediment can pose a potential 

risk to aquatic biota and human health.

Concern about the potential toxicity of trace elements to aquatic biota and human health has resulted in 

a comprehensive effort by State, Federal, and private 

entities to characterize the aquatic resources in the 

upper Clark Fork basin to guide and monitor remedial 

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

evaluate the effectiveness of remediation. Water-quality data have been collected by the U.S. Geological 

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

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

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

and others, 1996,1997,1998,1999,2000,2001,2002).

.S. Geological Survey, Menlo Park, Calif.

Abstract
u 12340500 '' DA'123 A

12340000

12334550

H

12334510^

Base modified from U.S. 

Geological Survey, State 

base map, 1:1,000,000, 

1966. North American 

Datum of 1927 (NAD 27)

123315001\ /

MONTANA

, Helena 

Study area

/ .12324680

-i 2324590 

0

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

XJ Periodic water quality 

V> Daily suspended sediment 

^~ Once-annual bed sediment 

~\7 Once-annual biota

12324200

E 

461903112440701- '^~

461 55911 2443301 

461415112450801

6a:enl »il2323800 2 f

V

12323750

 " * _A_

,, n,. n!ir,: sfV~ 12323600

12323250

10 20 MILES

10 20 KILOMETERS

Figure 1. Location of study area.

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; Cain and others, 1992 and 

1995; Axtmann and others, 1997; 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 

15 bed-sediment and 15 biological stations in the upper 

Clark Fork basin collected from October 2001 through 

September 2002 (water year 2002). Quality-assurance 

data are presented for water-quality, bed-sediment, and 

biota samples. Statistical summaries also are provided 

for water-quality, bed-sediment, and biological data 

collected since 1985.

Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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). Major tributaries were sampled to describe 

water-quality characteristics of important 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. Trace-element data for 

15 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 2002 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 2002 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 qualitycontrol 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 Ward and 

Harr (1990), Wilde and others (1998), and Edwards and 

Glysson (1999). These methods provide a vertically 

and laterally discharge-weighted composite sample 

that is representative of the entire flow through the 

cross section of a stream. Sampling equipment consisted of standard USGS depth-integrating suspendedsediment samplers (DH-48, DH-81, and D-74TM), 

which are either constructed of plastic or coated with a 

non-metallic epoxy paint, and equipped with nylon or 

Teflon 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 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 stagedischarge 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 from filtered (0.45-jLim 

pore size) samples for dissolved concentrations and 

unfiltered samples for total-recoverable concentrations. Dissolved concentrations of calcium and magnesium also were determined to enable calculation of 

hardness. 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 

2 to 10 times per week. These samples were collected 

by local contract observers using the depth-integration

SAMPLING LOCATIONS AND TYPES OF DATA
Table 1. Type and period of data collection at sampling stations in the upper Clark Fork basin, Montana

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

Q,a

i § g a

o

SL

Station number 

(fig. 1)

12323230

12323250

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324590

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

Station name

Blacktail Creek at Harrison Avenue, at 

Butte

Silver Bow Creek below Blacktail Creek, 

at Butte

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Warm Springs Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek diversion, 

near Racetrack

Clark Fork at Deer Lodge

Little Blackfoot River near Garrison

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below 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

10/77-P

08/90-P

04/93-P

10/72-P

03/85-P

10/39-P

03/29-P

10/29-P

Periodic water 

quality1

03/93-08/95, 

12/96-P

03/93-08/95, 

12/96-P

03/93-08/95, 

12/96-P

03/93-P

03/93-P

07/88-P

-

~

03/85-P

03/85-P

03/93-P

03/85-P

03/93-P

03/85-P

03/85-P

03/85-P

07/86-P3

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, 08/02

08/87, 

08/9 1-P

08/96-P

08/96-P

08/96-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, 

08/9 1-P

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

08/91-99,08/01,08/02

08/86, 

08/9 1-P

08/86, 08/87, 

08/91, 

08/93-96, 08/98-01

08/97-P

08/86, 

08/90-P

Bulk bed sedim

"

 

08/93-08/95

08/97-P

08/93, 

08/95-P

08/95, 08/97

88/99, 08/02

08/93-P

08/96-P

08/96-P

08/96-P

08/93-P

08/94, 08/98, 08

08/93-P

08/93-P

08/93-P

08/93-99,08/01,0

08/93-P

08/93, 08/94, 08/9

08/97-P

08/93-P

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

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. 

Bed sediment and biota sampled about 30 miles downstream from streamflow-gaging station to conform to previous sampling location.
Table 2. Properties measured onsite and constituents analyzed in samples 

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

Water

Property

Streamflow

Specific conductance

pH

Temperature

Constituent

Hardness

Calcium

Magnesium

Arsenic

Cadmium

Copper

Iron

Lead

Manganese

Zinc

Suspended sediment

Bed sediment

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Biota

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

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 2001 through September 2002 

(water year 2002) 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 2002 at the three daily suspended-sediment stations are given in tables 5 through 7. Monthly 

descriptive statistics for each parameter are provided 

along with totals for the annual discharge of water and 

suspended sediment.

Quality Assurance

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

described by Ward and Harr (1990), Knapton and 

Nimick (1991), Horowitz arid 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 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 blind-sample 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 evalWATER-QUALITY DATA
uation 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 acceptable limits for precision and bias of laboratory results. 

Comparisons of quality-control data to data-quality 

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 low-con6 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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

Precision

Maximum relative 

Laboratory standard deviation of

reporting laboratory replicate 

level1 analyses, 

in percent

Calcium, dissolved

Magnesium, dissolved

Arsenic, total recoverable

Arsenic, dissolved

Cadmium, total recoverable

Cadmium, dissolved

Copper, total recoverable

Copper, dissolved

Iron, total recoverable

Iron, dissolved

Lead, total recoverable

Lead, dissolved

Manganese, total recoverable

Manganese, dissolved

Zinc, total recoverable

Zinc, dissolved

Sediment, suspended

Sediment, suspended (percent finer than 0.062 mm)

0.01

.008

2

.2

.04-. 10

.04-. 10

.6

.2-1.0

10

10

1

.08-1

1-2.4

.1

1

1

1

1

mg/L

mg/L

ug/L

ug/L

ug/L

ug/L

ug/L

ug/L

ug/L

ug/L

ug/L

ug/L

ug/L

ug/L

ug/L

ug/L

mg/L

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 2002.

centration data (Childress and others, 1999). Qualitycontrol data are collected on a continuing basis to determine long-term method detection levels (LT-MDLs) 

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 replicate analyses can be used to 

estimate a standard deviation according to the following equation (Taylor, 1987):

where

o _

2k (1)

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.

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

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

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

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

RSD = - x 100 

x

(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 (table 3). 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 total-recoverable and 

dissolved cadmium. 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:

0 ., . , spike sample concentration - unspiked sample concentration . Spike recovery, in percent= -* c c : c x 100

spike concentration

(3)

Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 

95.1 to 105.1 percent. The mean spike recovery for 

spiked stream samples ranged from 92.6 to 107.1 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 deionized-water blank samples 

(table 11) had confidence intervals for percent recovery 

that included 100 percent, except total-recoverable 

cadmium (96.3-98.9) percent. All laboratory-spiked 

stream samples (table 12) had confidence intervals for 

percent recovery that included 100 percent, except dissolved iron (103-111) percent. Because the mean spike 

recoveries for all constituents met data-quality objectives, no adjustments were made to analytical results 

for stream samples on the basis of spike recoveries.

Analytical results for field blanks are presented in 

table 13. A field blank with constituent concentrations 

equal to or less than the 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. Minor exceedances 

were noted for dissolved calcium, dissolved magnesium, dissolved cadmium, dissolved manganese, and 

total-recoverable zinc. 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 water-quality data for stream samples.

BED-SEDIMENT DATA

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

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

Bed-sediment samples are collected once-annually 

during low, stable flow conditions and the same season 

(typically August) to facilitate data comparisons 

among years.

Methods

Bed-sediment samples were collected in August 

2002 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 nylonmesh sieve using ambient stream water. The fraction of 

bed sediment in each composite sample that was finer 

than 0.064 mm was transferred to an acid-washed 500- 

mL polyethylene bottle and transported to the laboratory on ice.

BED-SEDIMENT DATA
Individual samples of bulk bed sediment also 

were collected by scooping material from the surfaces 

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 bed-sediment samples were oven-dried at 60°C and ground 

using an acid-washed ceramic mortar and pestle. 

Duplicate aliquots of approximately 0.6 g of sediment 

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

nitric acid reflux according to methods described by 

Luoma and Bryan (1981). Duplicate 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 2002 are summarized in tables 14 

and 15, respectively. Liquid-phase concentrations, in 

|ig/mL, that were analyzed in the reconstituted aliquots 

of digested bed sediment were converted to solid-phase 

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

M g/g = |ug/mL x volume of digested sample, in mL 

dry weight of sample, in g x dilution ratio

(4)

The reported solid-phase concentrations in tables 

14 and 15 are the means of all analyses of duplicate aliquots from each composite sample collected at the site. 

Because the conversion from liquid-phase to solidphase 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 laboratorygrade detergent and rinsed with deionized water. All 

equipment was given a final rinse onsite with stream 

water. Sampling equipment that was reused at each site 

was rinsed between sites with 10-percent nitric acid, 

deionized water, and stream water. Separate sieves 

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

between-site cleaning.

Quality assurance of analytical results for bed 

sediment included laboratory instrument calibration 

with standard solutions and analysis of quality-control 

samples designed to identify the presence and magnitude of bias (E.V. Axtmann, 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 bedsediment samples is not a "total" digestion (does not 

liberate elements associated with crystalline lattices);

10 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
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 sediment-binding characteristics and whether analytical recovery is consistent 

between multiple sets of analyses.

Although data-quality objectives have not been 

established for bed sediment, the mean SRM recoveries 

(in percent) are shown in table 16 to illustrate analytical 

performance. Copper for both low-concentration range 

(SRM 2709) and high-concentration range (SRM 

2711) showed consistently low recoveries (71.3 and 

74.6 percent, respectively). 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. Also, in SRM 2711, 

chromium and manganese showed low recoveries 

(36.3 and 78.6 percent, respectively). Mean recoveries 

for all other constituents in both low- and high-concentration SRMs ranged from about 80 to 105 percent; 

thus, mean recoveries 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 ug/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 chromium and iron) 

above the analytical detection limit. However, both 

concentrations 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 trace-element concentrations in the whole-body tissue of 

aquatic benthic insects. Insect samples were collected 

once-annually at the same sites and dates as bed-sediment samples (table 1), allowing for a direct comparison of biological data among years and with bedsediment 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 tax on 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 and is consistent with methods established by Cain and Luoma (1998). However,

BIOLOGICAL DATA 11
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 and 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-|im 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 2002 

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 stationto-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 SRM 

recoveries were within 10 percent of certified values 

for copper, iron, and manganese. Recoveries for cadmium, chromium, nickel, and zinc were within 16 percent. Lead recoveries were low (mean SRM of 62.2 

percent) due to the very low solution concentration of 

lead in the biota standard (less than 10 parts per billion). However, because the solution concentration in 

the samples were two to ten-fold higher than the reference standard, adjustments to the data were not necessary. 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.

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

12 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
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, bed-sediment, and biological data are provided in tables 21-24 

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

summaries include the period of record, number of 

samples, maximum, minimum, mean, and median of 

concentrations.

Statistical summaries of water-quality data (table 

21) are based on results of cross-sectional samples collected periodically by the USGS during the station's 

period of record. The summaries do not include data 

for 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. 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 abundance at 

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

for biota describe a wider range of variation in traceelement 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.

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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., 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

14 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
1986: U.S. Geological Survey Open-File Report 

87-110, 48 p.

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, GW, 1981, A statistical 

assessment of the form of trace metals in oxidized 

estuarine sediments employing chemical 

extractants: Science of the Total Environment, 

v. 17, no. 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 2001 through September 2002) 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 2001 through September 2002

[Abbreviations: ft /s, cubic feet per second; °C, degrees Celsius; E, estimated; ng/L, micrograms per liter; ^S/cm, microsiemens per centimeter at 25 °C; 

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

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

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

03...

24...

AUG

20...

Streamflow, pH, Specific Temper- Hardness, 

rp. instan- onsite conductance, ature, total 

taneous (standard onsite water (mg/L as 

(ft3/s) units) (juS/cm) (°C) CaCO3)

1415 3.8 7.9 326 8.5 130

0810 3.1 7.7 321 3.5 120

0900 9.2 7.7 235 3.0 90

0935 4.8 8.0 303 7.0 120

0910 4.7 7.8 300 10.5 120

1720 15 7.8 250 14.0 94

1210 E4.8 7.9 315 14.0 120

1220 8.5 8.1 338 12.5 130

Calcium, 

dissolved 

(mg/L)

35.9

35.5

25.6

32.7

34.3

27.3

34.8

38.6

Magnesium, 

dissolved 

(mg/L)

8.67

8.83

6.41

8.58

8.19

6.40

8.42

9.34

Arsenic, 

dissolved

(Hg/L)

1.4

1.1

3.3

2.2

2.7

4.6

2.9

2.0

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

03...

24...

AUG

20...

Arsenic, , . Cadmium, Copper, 

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

, . dissolved , , dissolved , . recoverable , _ recoverable , . recoverable (uWL) fuc/L) (Hg/L) (ug/L) vw* (|ig/L)

2 <0.1 <0.1 E0.8 4.6

<2 <.l <.l <1.0 3.6

4 .1 <.l 4.8 9.2

2 .1 <.l 2.8 4.4

3 E.02 E.02 2.1 3.2

6 E.03 .06 6.0 10.0

3 .08 E.03 2.1 3.2

2 E.02 <.04 1.1 1.7

Iron, 

dissolved

18

44

231

72

73

184

47

15

Iron, 

total 

recoverable

580

430

860

340

290

780

260

150

Lead, 

dissolved

(Hg/L)

<1

<.08

.23

E.08

<.08

.22

E.05

<.08

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

03...

24...

AUG

20...

Lead, Manga- . Zinc, 

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

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

Qif/L) (Hg/L) recova-able (ugrt.) (^g/L)

1 34.5 50 2 7

<1 39.8 52 3 6

2 144 173 4 8

<1 47.9 58 4 9

<1 38.6 45 2 3

2 30.4 58 4 9

<1 36.7 42 3 3

<1 26.3 29 1 2

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

81

80

80

77

65

78

82

80

Sediment, 

suspended 

(mg/L)

11

21

15

7

6

15

4

2

Sediment 

discharge, 

suspended 

(ton/d)

0.11

.18

.37

.09

.08

.60

E.05

.05

TABLE 4 17
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2001 through September 2002 (Continued) 

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

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

03...

24...

AUG

20...

Streamflow, pH, Specific Temper- Hardness, 

 . instan- onsite conductance, ature, total 

taneous (standard onsite water (mg/L as 

(ft3/s) units) (nS/cm) (°C) CaCO3)

1440 18 7.6 590 9.5 180

0920 18 7.5 561 4.5 170

1015 21 7.6 443 5.0 130

1040 18 7.5 500 8.5 140

1015 18 7.7 516 12.5 160

1820 27 7.7 418 15.5 130

1245 16 8.0 519 17.0 170

1250 16 7.8 574 17.5 170

Calcium, 

dissolved 

(mg/L)

50.7

47.9

37.5

40.7

46.0

38.5

48.6

49.4

Magnesium, 

dissolved 

(mg/L)

12.7

12.0

9.49

10.3

11.1

9.13

12.0

12.4

Arsenic, 

dissolved

(Hg/L)

7.5

7.8

4.3

4.6

5.5

7.3

7.7

7.4

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

03...

24...

AUG

20...

Arsenic, , . Cadmium, , Copper, 

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

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

(nan.) (^g/L) QitfD ^ QitfD

11 1.2 1.5 13.8 36.0

9 E.I .4 4.5 28.3

6 .2 .3 10.5 23.3

4 .2 .3 8.9 18.8

6 .12 .21 5.3 16.0

9 .14 .36 10.9 23.6

8 .20 .24 9.2 16.6

9 .11 .18 8.1 13.5

Iron, 

dissolved

(Hg/L)

17

28

80

34

27

117

14

14

Iron, 

total 

recoverable

(Hg/L)

390

640

530

290

280

690

260

90

Lead, 

dissolved

(H8/L)

<1

.24

.32

.20

.15

.46

.12

.17

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

03...

24...

AUG

20...

Lead, Manga- Manga- n 

... B nese, Zinc, , , ' total nese, ... ,. . , total 

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

(W^L) (W*L) reC(0;^ble ^ (W^L)

4 262 298 309 374

7 144 179 90 128

4 151 171 94 106

2 177 194 86 107

1 166 188 82 91

5 113 149 60 93

2 148 165 66 88

<1 21.4 29 71 86

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

92

87

85

71

75

92

89

81

Sediment, 

suspended 

(mg/L)

14

19

12

11

7

14

11

5

Sediment 

discharge, 

suspended 

(ton/d)

.68

.92

.68

.53

.34

1.0

.48

.22

18 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through September 2002 (Continued)

12323600-SILVER BOW CREEK AT OPPORTUNITY, MONT.

Date

NOV 2001

07...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

03...

24...

AUG

20...

Streamflow,

Time instantaneous

(ft3/s)

0810 27

1030 E29

1110 42

1140 39

1125 60

1915 94

1405 49

1400 14

pH, Specific Temper- Hardness 

onsite conductance, ature, total 

(standard onsite water (mg/L as 

units) (jiS/cm) (°C) CaCO3)

8.1 555 1.5 190

7.8 555 0.0 190

8.2 395 5.0 130

8.9 433 7.5 160

8.5 364 12.0 140

8.2 322 14.0 130

8.9 368 19.5 140

9.5 527 20.0 190

' Calcium, 

dissolved 

(mg/L)

57.0

54.4

38.9

46.5

43.0

38.4

43.1

53.4

Magnesium, 

dissolved 

(mg/L)

12.6

12.3

8.81

9.77

7.78

7.21

8.28

12.8

Arsenic, 

dissolved

(H8/L)

9.1

13.0

15.2

11.3

10.3

11.3

11.9

18.7

Date

NOV 2001

07...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

03...

24...

AUG

20...

Arsenic, , . 

... Cadmium, total ,. . ' 

, , dissolved recoverable _

(Hg/L) WU

16 1.3

16 1.4

63 .8

16 .4

15 .25

21 .38

16 .22

23 .46

Cadmium, Copper,

total .9*?"' total 

,. dissolved ,, recoverable . _ . recoverable

2.0 30.1 101

1.6 43.7 102

1.8 61.2 283

.8 29.3 85.8

.69 19.5 86.2

1.34 31.5 154

.61 19.9 76.9

.89 40.7 98.5

Iron, 

dissolved

(Hg/L)

<10

12

22

17

21

45

14

17

Iron, 

total 

recoverable

(Hg/L)

410

530

1,770

550

620

1,140

490

280

Lead, 

dissolved

(Rg/L)

<1

.30

.61

.33

.28

.88

.25

.40

Date

NOV 2001

07...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

03...

24...

AUG

20...

Lead, Mangatotal nese, 

recoverable dissolved

12 478

14 372

101 492

15 336

15 192

32 234

12 141

7 140

Manga- . Zinc,

IT,' . T'., total total dissolved , , 

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

(Hg/L) (*>&lj)

508 487 656

436 343 405

612 224 416

424 77 221

285 59 162

439 95 287

208 34 143

196 29 151

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

78

56

91

78

74

74

85

57

Sediment, 

suspended 

(mg/L)

13

14

43

14

17

35

13

7

Sediment 

discharge, 

suspended 

(ton/d)

.95

El.l

4.9

1.5

2.8

8.9

1.7

.26

TABLE 4 19
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2001 through September 2002 (Continued)

12323750-SILVER BOW CREEK AT WARM SPRINGS, MONT

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

04...

24...

AUG

20...

Streamflow, pH, Specific Temper- Hardness, 

rp. instan- onsite conductance, ature, total 

taneous (standard onsite water (mg/L as 

(frVs) units) (nS/cm) (°C) CaCO3)

1620 34 9.0 637 7.0 270

1130 46 8.3 675 4.0 290

1225 51 8.4 581 7.5 240

1230 53 8.4 541 10.0 220

1225 107 8.8 376 15.5 150

0835 186 8.5 372 10.0 140

1505 140 9.0 287 18.5 110

1500 22 9.2 555 20.0 240

Calcium, 

dissolved 

(mg/L)

75.1

83.4

69.9

64.3

41.7

39.7

29.1

69.4

Magnesium, 

dissolved 

(mg/L)

19.0

19.0

16.1

14.4

10.0

10.4

8.00

17.3

Arsenic, 

dissolved

(Hg/L)

17.4

11.8

8.5

13.3

23.8

34.1

31.3

26.2

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

04...

24...

AUG

20...

Arsenic, , . Cadmium, , Copper, 

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

,, dissolved ,, dissolved ,, recoverable _ , recoverable , ~ recoverable

(|Xg/L) (|Xg/L) (|xg/L)

22 <.l <.l 2.5 5.2

13 E.I .1 7.4 9.9

13 <1 .5 3.3 24.8

17 <.l .1 3.6 10.5

28 .05 .16 5.5 13.0

38 .06 .17 7.3 12.7

34 .07 .13 6.7 10.6

30 E.03 .06 3.7 5.6

Iron, 

dissolved

(\igfL)

<10

17

<10

12

15

25

23

E8

Iron, 

total 

recoverable

(Hg/L)

140

160

540

300

330

250

180

120

Lead, 

dissolved

(Hg/L)

<1

E.05

E.05

E.07

.10

.12

.15

E.07

Date

NOV 2001

06...

MAR 2002

14...

APR

OSMAY

06...

29...

JUN

04...

24...

AUG

20...

Lead, Manga- Manga- Zj. 

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

recoverable dissolved , _ recoverable

(jig/L) (jig/L) _ vHB' > (|ig/L)

<1 33.8 74 2 9

<1 301 333 21 27

4 135 207 7 75

2 126 219 6 22

2 45.5 137 4 18

2 38.0 82 6 17

1 23.0 69 3 11

<1 40.5 109 2 6

Sediment, 

suspended 

(percent 

Finer than 

0.062 mm)

75

87

97

90

86

87

90

83

Sediment, 

suspended 

(mg/L)

7

4

6

10

13

9

5

7

Sediment 

discharge, 

suspended 

(ton/d)

.64

.50

.83

1.4

3.8

4.5

1.9

.42

20 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through September 2002 (Continued)

12323770-WARM SPRINGS CREEK AT WARM SPRINGS, MONT.

Date

NOV 2001

06...

APR 2002

08...

MAY

29...

JUN

04...

24...

AUG

20...

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

 i ! J^ ^ ^ . Calcium, 

 . mstan- onsite conductance, ature, total ,. . , smm, Time , . . , , ., ' ' , dissolved ,. , ' taneous (standard onsite water (mg/L as , _ , dissolved

(ft3/s) units) (nS/cm) (°C) CaCO3) (m& ' (mg/L)

1605 41 8.5 331 5.5 160 47.5 9.53

1210 34 8.4 358 5.5 170 51.6 10.5

1210 59 8.4 260 14.0 130 38.7 7.07

0810 101 8.0 191 7.5 89 27.7 4.92

1440 95 8.3 186 15.5 40 10.5 3.29

1440 27 8.6 317 16.5 150 47.7 8.67

Arsenic, 

dissolved

(Hg/L)

4.2

4.6

5.3

3.9

4.8

7.5

Date

NOV 2001

06...

APR 2002

08...

MAY

29...

JUN

04...

24...

AUG

20...

Arsenic, . . Cadmium, , Copper, T Iron, 

, . . Cadmium, , . . Copper, , *" , Iron, . . ! total ,. . , total ,. , ' total ,. , ' total 

,, dissolved ,. dissolved ,. dissolved ,, recoverable , _ , recoverable . _ , recoverable , , recoverable (Llfi/L) 1U.S/L) (LIS/L)

5 E.I <.l El.l 3.9 <10 40

5 <.l <.l 2.9 6.2 <10 60

5 E.03 .07 3.6 14.4 <10 200

5 E.03 .07 2.9 14.8 E9 270

7 .04 .05 3.1 11.0 E8 140

9 E.03 .04 3.1 7.3 E6 70

Lead, 

dissolved

<1

<.08

<.08

E.05

E.05

E.05

Date

NOV 2001

06...

APR 2002

08...

MAY

29...

JUN

04...

24...

AUG

20...

¥ , -,, Manga- . Sediment, Lead, Manga- _. Zinc, ,1 ,. 

, , , nese, Zinc, . . . suspended Sediment, total nese, A A , ,. , ' total . , , ' 

, , ,. , ' total dissolved . , (percent suspended recoverable dissolved , , , _ . recoverable . .. , x 

 , , . recoverable (UR/L) , n ^ finer than (mg/L)

(^g/L) (^8/L) (u^L) (W^> 0.062mm)

<1 95.2 118 1 3 57 3

<1 173 206 2 2 80 3

1 63.8 205 <1 5 66 10

1 67.8 157 2 7 61 14

<1 45.3 115 1 4 62 10

<1 22.6 99 1 2 76 3

Sediment 

discharge, 

suspended 

(ton/d)

.33

.28

1.6

3.8

2.6

.22

TABLE 4 21
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2001 through September 2002 (Continued)

12323800-CLARK FORK NEAR GALEN, MONT.

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

04...

24...

AUG

20...

Streamflow, pH, Specific Temper- 

 . instan- onsite conductance, ature, 

taneous (standard onsite water 

(ft3/s) units) (nS/cm) (°C)

1640 87 8.8 480 5.5

1230 96 8.3 554 3.0

1315 91 8.4 496 7.5

1310 76 8.6 481 9.0

1320 164 8.9 342 16.0

0715 300 8.2 308 10.5

1605 255 8.9 252 18.0

1605 49 8.8 457 18.0

Hardness, 

total 

(mg/L as 

CaCO3)

210

240

210

210

140

120

99

210

Calcium, 

dissolved 

(mg/L)

61.4

71.7

62.2

62.2

42.1

35.7

28.5

61.4

Magnesium, 

dissolved 

(mg/L)

14.0

15.8

13.5

13.4

9.31

8.39

6.82

13.2

Arsenic, 

dissolved

(Hg/L)

10.4

8.3

6.9

10.4

17.9

24.3

22.1

16.2

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

04...

24...

AUG

20...

Arsenic, , . Cadmium, 

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

, , dissolved , , dissolved recoverable , n , recoverable , n

(Hg/L) ( ^} (ng/L) vW

13 <.l <.l 2.3

9 <.l E.I 5.8

9 <.l .2 3.4

11 <.l <.l 3.4

22 .04 .14 5.1

28 .06 .23 6.2

24 .12 .10 6.6

18 E.04 .06 3.9

Copper, 

total 

recoverable

(Hg/L)

5.1

10.3

13.3

7.6

15.8

28.8

13.6

6.7

Iron, 

dissolved

<10

E6

<10

E6

E8

22

14

E5

Iron, 

total 

recoverable

70

130

270

140

310

510

190

70

Lead, 

dissolved

(HSfL)

<1

E.04

E.06

E.05

E.06

.10

.17

E.04

Date

NOV 2001

06...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

04...

24...

AUG

20...

Lead, Manga- Manga' 

... nese, Zinc, total nese, , 4 ' ,. . ' 

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

(Hg/L) <W*L> "^j C ^

<1 41.2 65 2

<1 204 248 13

2 113 170 7

<1 101 142 5

2 42.6 167 2

4 45.0 217 5

1 27.5 98 3

<1 29.8 70 2

Zinc, 

total 

recoverable

5

18

31

10

16

29

11

5

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

71

76

86

84

78

66

78

80

Sediment, 

suspended 

(mg/L)

4

5

5

5

13

24

9

3

Sediment 

discharge, 

suspended 

(ton/d)

.94

1.3

1.2

1.0

5.8

19.4

6.2

.40

22 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through September 2002 (Continued)

12324200-CLARK FORK AT DEER LODGE, MONT.

Date

NOV 2001

07...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

04...

24...

AUG

22...

Streamflow, pH, Specific Temper- Hardness, 

 ,. instan- onsite conductance, ature, total 

taneous (standard onsite water (mg/L as 

(ft3/s) units) (nS/cm) (°C) CaCO3)

0915 172 8.3 551 3.0 240

1330 201 8.4 551 3.0 240

1410 190 8.4 524 9.0 220

1410 132 8.6 527 10.5 230

1415 141 8.8 445 17.5 190

0945 305 8.1 360 12.0 150

1705 325 8.9 334 20.0 140

0735 97 8.0 541 12.0 230

Calcium, 

dissolved 

(mg/L)

70.5

71.9

66.0

68.6

57.3

43.9

40.0

68.2

Magnesium, 

dissolved 

(mg/L)

16.3

15.6

14.3

14.8

12.1

9.82

9.20

14.4

Arsenic, 

dissolved

8.3

10.1

9.7

10.6

16.6

18.7

22.2

12.7

Date

NOV 2001

07...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

04...

24...

AUG

22...

Arsenic, , . Cadmium, Copper, 

... Cadmium, , . . Copper, , ^ , total ,. , ' total ,. , ' total 

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

(Hg/L) ^ Qig/L) ^& (HS/L)

11 <.l E.I 3.2 15.4

14 <.l .2 7.2 44.8

15 E.I E.I 6.5 37.0

11 <.l E.I 6.1 15.5

19 .04 .11 7.8 20.4

32 .05 .57 9.6 92.4

26 .06 .17 9.4 33.8

13 .08 .06 10.7 15.7

Iron, 

dissolved

(Hg/L)

<10

E10

<10

<10

<10

21

E9

E5

Iron, 

total 

recoverable

(Hg/L)

190

700

510

170

220

1,450

390

100

Lead, 

dissolved

(Hg/L)

<1

.09

E.08

E.04

<.08

.21

.09

E.05

Date

NOV 2001

07...

MAR 2002

14...

APR

08...

MAY

06...

29...

JUN

04...

24...

AUG

22...

Lead, Manga- Manga- Zj 

... nese, Zinc, . . . total nese, 4 . . ,. . ' total 

, . ,. . ' total dissolved , , recoverable dissolved . . < n\ recoverable

((ig/L) (|ig/L) . _ . (Hg/L)

2 29.4 79 7 22

6 50.1 157 13 44

5 48.9 126 8 33

2 47.7 78 5 15

2 27.8 82 2 16

13 23.1 328 9 90

4 18.1 95 2 25

<1 8.5 16 8 11

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

74

72

79

80

82

68

78

85

Sediment, 

suspended 

(mg/L)

14

39

23

10

11

69

23

4

Sediment 

discharge, 

suspended 

(ton/d)

6.5

21.2

11.8

3.6

4.2

56.8

20.2

1.0

TABLE 4 23
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2001 through September 2002 (Continued)

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON, MONT.

Streamflow, pH, Specific Temper- Hardness,

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

(ft3/s) units) (nS/cm) (°C) CaCO3)

NOV 2001

08... 0835 63 8.1 284 .5 130

APR 2002

09... 0925 197 8.1 206 3.0 88

MAY

29... 1530 414 8.2 180 15.5 80

JUN

04... 1125 372 8.1 194 10.5 86

24... 1830 289 8.4 222 19.5 100

AUG

21... 1715 51 8.6 265 15.5 120

Calcium, 

dissolved 

(mg/L)

37.6

25.5

23.2

24.8

29.7

35.0

Magnesium, 

dissolved 

(mg/L)

8.71

5.92

5.38

5.74

6.75

8.11

Arsenic, 

dissolved

(Hg/L)

3.9

5.3

5.1

5.1

6.0

5.5

Arsenic, , . Cadmium, Copper, 

... Cadmium, ' Copper, . . . ' 

r» * tota' j- i j total ,. , ' total Date . . dissolved . . dissolved , , recoverable , , recoverable . _ , recoverable 

(Lig/L) (ug/L) (|ig/L) (|ig/L) (|Xg/L)

NOV 2001

08... 5 <.l <.l <1.0 .9

APR 2002

09... 6 <.l <.l 2.3 2.5

MAY

29... 6 <.04 .04 1.6 2.9

JUN

04... 6 <.04 E.03 1.3 2.0

24... 6 E.02 E.02 1.2 1.6

AUG

21... 6 <.04 E.02 .7 1.0

Iron, 

dissolved

<10

79

36

30

21

<10

Iron, 

total 

recoverable

40

380

590

280

160

70

Lead, 

dissolved

(HSfL)

<1

.13

E.07

E.06

E.05

E.05

Lead, Manga- Manga- zi 

... nese, Zinc, . . , 

r. . total nese, , 4 ' ,. . ' total Date , , ,. . ' total dissolved , , recoverable dissolved , _ recoverable

(|ig/L) (jig/L) n ^ff > (|ig/L)

NOV 2001

08... <1 2.5 6.8 <1 1

APR 2002

09... <1 9.5 35 2 3

MAY

29... 1 8.2 44 1 6

JUN

04... <1 7.9 25 1 4

24... <1 9.0 21 1 2

AUG

21... <1 5.4 16 1 1

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

81

84

58

73

84

94

Sediment, 

suspended 

(mg/L)

2

15

35

13

7

3

Sediment 

discharge, 

suspended 

(ton/d)

.34

8.0

39.1

13.1

5.5

.41

24 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through September 2002 (Continued)

12324680-CLARK FORK AT GOLDCREEK, MONT.

Date

NOV 2001

07...

MAR 2002

14...

APR

09...

MAY

06...

29...

JUN

04...

25...

AUG

21...

Streamflow, pH, Specific Temper- Hardness, . .

T. instan- onsite conductance, ature, total ,. . j Time . , , . , ' ' . _ dissolved taneous (standard onsite water (mg/L as ( n\

(ft3/s) units) (HS/cm) (°C) CaCO3) (m&Ll)

1120 299

1450 326

1015 454

1535 281

1630 718

1220 928

0730 732

1555 175

8.5 489 4.0 210

8.6 474 4.0 210

8.3 365 5.5 150

8.5 408 11.0 180

8.7 272 16.0 120

8.4 270 12.0 120

8.2 307 15.0 130

8.6 427 15.5 190

62.0

61.4

45.5

53.2

34.2

35.1

38.9

55.1

Magnesium, 

dissolved 

(mg/L)

13.7

13.3

10.0

11.7

7.59

7.67

8.38

11.8

Arsenic, 

dissolved

(Hg/D

6.9

9.4

8.1

8.1

7.7

10.6

12.4

10.1

Date

NOV 2001

07...

MAR 2002

14...

APR

09...

MAY

06...

29...

JUN

04...

25...

AUG

21...

Arsenic, , . 

... Cadmium, total .. , '

recoverable df°'Vf

(Hg/L) (^8/L)

9 <.l

12 <1

11 <1

8 <.l

9 E.03

16 E.03

13 .04

10 E.03

Cadmium, Copper,

total riC°PPer' total 

, . dissolved , , recoverable , recoverable

(Hg/L) WWW (^g/L)

E.I 2.1 13.0

.2 8.8 40.8

.1 5.4 28.3

<.l 4.0 12.8

.12 4.2 16.3

.27 5.6 45.4

.14 5.7 22.9

.04 3.5 5.7

Iron, 

dissolved

(Hg/L)

<10

22

35

<10

13

19

12

<10

Iron, 

total 

recoverable

(Hg/D

190

680

710

230

560

780

370

50

Lead, 

dissolved

(Hg/D

<1

.13

.13

<.08

E.04

.14

E.08

.10

Date

NOV 2001

07...

MAR 2002

14...

APR

09...

MAY

06...

29...

JUN

04...

25...

AUG

21...

Lead, Mangatotal nese, 

recoverable dissolved

(Hg/L) (ng/L)

2 13.6

5 33.9

4 15.7

2 17.0

2 10.0

7 10.5

3 13.9

<1 7.6

Manga' . Zinc, 

nese, Zinc, , , . 

, . j. i j total total dissolved , . 

, . . , recoverable recoverable (Hg/L) , , / /r^ (Hg/L) (Hg/L) ^w

66 3 17

130 8 44

105 5 30

53 2 14

73 1 18

153 4 45

75 4 23

21 2 4

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

72

71

73

87

84

84

77

79

Sediment, 

suspended

(mg/L)

14

38

38

14

30

37

18

3

Sediment 

discharge, 

suspended 

(ton/d)

11.3

33.4

46.6

10.6

58.2

92.7

35.6

1.4

TABLE 4 25
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2001 through September 2002 (Continued)

12331500-FLINT CREEK NEAR DRUMMOND, MONT.

Date

NOV 2001

07...

MAR 2002

13...

APR

09...

MAY

08...

29...

JUN

04...

25...

AUG

20...

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)

1220 119 8.6 350 4.5 160

1640 125 8.5 305 2.5 130

1110 84 8.4 301 4.5 130

0930 31 8.5 360 4.0 170

1725 19 8.8 306 20.5 140

1320 83 8.4 276 13.5 130

0830 112 8.1 353 12.5 160

1740 11 8.5 483 18.0 220

Calcium, 

dissolved 

(mg/L)

43.4

33.3

35.3

45.7

39.7

35.2

44.6

59.4

Magnesium, 

dissolved 

(mg/L)

12.5

10.4

10.9

13.1

10.8

9.51

12.3

17.8

Arsenic, 

dissolved

6.2

10.9

7.3

7.5

11.9

9.7

10.3

11.6

Date

NOV 2001

07...

MAR 2002

13...

APR

09...

MAY

08...

29...

JUN

04...

25...

AUG

20...

Arsenic, , . Cadmium, Copper, 

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

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

, . (Ug/L) . . (ug/L) , (Ug/L) ^w (Ug/L) (M-g/L)

9 <.l <.l <1.0 1.4

15 <.l E.1 4.4 7.2

12 <1 <.l El.O 3.6

8 <.l <.l E.8 1.4

14 E.02 .05 1.4 2.8

14 <.04 .07 1.4 3.4

13 E.02 .06 1.3 3.1

12 <04 <.04 1.3 1.9

Iron, 

dissolved

(Hg/L)

<10

99

21

E6

E8

19

20

E9

Iron, 

total 

recoverable

(Hg/L)

130

720

470

130

270

400

260

100

Lead, 

dissolved

<1

.67

.25

.10

.12

.26

.20

E.06

Date

NOV 2001

07...

MAR 2002

13...

APR

09...

MAY

08...

29...

JUN

04...

25...

AUG

20...

Lead, Manga- " _. Zinc, 

total nese, "efse; . Zlnc' total 

recoverable dissolved recoerabl (eJlUl recoverable

(Hg/L) (p,g/L) _ Wsf > (p,g/L)

2 21.5 53 1 7

9 54.2 182 9 29

7 39.7 137 2 19

2 57.6 84 2 5

4 39.3 147 1 11

7 36.9 144 2 19

5 48.6 125 2 15

<1 50.7 80 1 3

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

87

78

88

88

92

86

87

88

Sediment, 

suspended

(mg/L)

8

52

29

8

17

26

15

4

Sediment 

discharge, 

suspended 

(ton/d)

2.6

17.6

6.6

.67

.87

5.8

4.5

.12

26 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through September 2002 (Continued)

12331800-CLARK FORK NEAR DRUMMOND, MONT.

Date

NOV 2001

07...

MAR 2002

13...

APR

09...

MAY

08...

30...

JUN

04...

25...

AUG

21...

Streamflow, pH, Specific Temper- Hardness, 

j,. instan- onsite conductance, ature, total 

taneous (standard onsite water (mg/L as 

(ft3/s) units) (nS/cm) (°C) CaCO3 )

1340 498 8.4 498 6.0 220

1510 698 8.2 411 3.5 180

1200 650 8.3 418 8.0 180

1025 420 8.5 480 7.5 220

1045 768 8.2 349 16.0 160

1430 1,120 8.3 324 15.0 140

0945 963 8.3 373 17.5 160

1435 223 8.5 559 17.5 260

Calcium, 

dissolved 

(mg/L)

63.2

51.1

52.2

62.7

45.1

41.5

47.5

73.7

Magnesium, 

dissolved

(mg/L)

15.1

11.9

12.3

14.7

10.3

9.42

11.1

18.3

Arsenic, 

dissolved

(|J.g/L)

7.5

9.7

8.9

8.6

9.6

11.9

12.3

11.3

Date

NOV 2001 

07...

MAR 2002

13...

APR

09...

MAY

08...

30...

JUN

04...

25...

AUG

21...

Arsenic, . Cadmium, Copper, 

, , , Cadmium, ... Copper, , . , total ,. , ' total j. , j total 

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

10 <.l E.I 2.0 9.3

12 E.I .2 12.5 44.0

13 <.l .2 5.8 32.4

9 <.l <.l 3.7 10.7

13 E.04 .25 5.5 33.8

18 E.03 .43 6.4 60.7

14 .04 .13 6.0 21.6

10 E.03 .04 3.0 4.9

Iron, 

dissolved

<10

51

12

<10

E8

12

E8

<10

Iron, 

total 

recoverable

180

1,190

780

190

780

1,220

360

40

Lead, 

dissolved

(Hg/L)

<!

.30

.14

<.08

E.06

.16

.09

<.08

Date

NOV 2001

07...

MAR 2002

13...

APR

09...

MAY

08...

30...

JUN

04...

25...

AUG

21...

Lead, Manga- anga- Zinc, 

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

, , ,. , , total dissolved , , recoverable dissolved ., , . recoverable recoveraDle (Li£7i^)

2 7.5 53 3 18

8 27.9 160 13 70

6 11.4 116 6 44

1 15.3 48 4 14

5 10.0 118 4 44

10 10.4 190 5 76

3 10.9 74 4 25

<1 10.9 23 3 6

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

66

51

70

90

84

75

80

67

Sediment, 

suspended 

(mg/L)

17

96

52

11

47

71

19

4

Sediment 

discharge, 

suspended 

(ton/d)

22.9

181

91.3

12.5

97.5

215

49.4

2.4

TABLE 4 27
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2001 through September 2002 (Continued)

12334510-ROCK CREEK NEAR CLINTON, MONT.

Date

NOV 2001

07...

APR 2002

09...

MAY

23...

JUN

04...

25...

AUG

21...

Streamflow, pH, Specific Temper- Hardness, 

 . instan- onsite conductance, ature, total 

taneous (standard onsite water (mg/L as 

(ft3/s) units) (HS/cm) (°C) CaCO3)

1445 215 8.3 148 5.0 67

1310 270 8.2 125 5.5 53

1145 1,610 7.7 69 5.0 28

1620 2,080 7.8 68 10.0 30

1130 1,080 8.0 92 13.0 40

1320 241 8.2 136 12.5 61

Calcium, 

dissolved

(mg/L)

17.5

13.4

7.23

7.70

10.5

15.6

Magnesium, 

dissolved 

(mg/L)

5.80

4.84

2.46

2.50

3.39

5.35

Arsenic, 

dissolved

.5

.6

.6

.6

.6

.6

Date

NOV 2001

07...

APR 2002

09...

MAY

23...

JUN

04...

25...

AUG

21...

Arsenic, . . Cadmium, _ Copper, 

... Cadmium, ... Copper, . \ , total ,. . ' total _,. , j total 

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

(Hg/L) ^ (Hg/L) ^ (H8/L)

<2 <.l <.l <1.0 E.3

<2 <.l <.l <1.0 E.6

<2 .04 E.02 1.0 1.5

<2 <.04 <.04 .7 1.8

5 E.02 <.04 .5 .9

<2 <.04 <.04 .3 E.5

Iron, 

dissolved

<10

17

52

29

22

E9

Iron, 

total 

recoverable

30

80

260

190

120

40

Lead, 

dissolved

(Hg/D

<1

<.08

<08

<.08

<.08

<08

Date

NOV 2001

07...

APR 2002

09...

MAY

23...

JUN

04...

25...

AUG

21...

Lead, Manga- _. Zinc, 

total nese, "ese' ,' total 

recoverable dissolved tOtal . . dissolved recoverable 

/ IT \ / n -, recoverable (Hg/L) , .. (Hg/L) (H8/L) , n (Hg/L)

<1 .8 E2.5 <1 1

<1 .8 3.6 <1 <1

<1 1.7 13 2 2

<1 1.8 10 <1 2

<1 2.2 7 <1 <1

<1 1.8 5 <1 <1

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

73

82

63

57

73

80

Sediment, 

suspended

(mg/L)

3

4

17

15

7

3

Sediment 

discharge, 

suspended 

(ton/d)

1.7

2.9

73.9

84.2

20.4

2.0

28 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through September 2002 (Continued)

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

Date

NOV 2001

08...

MAR 2002

13...

APR

09...

MAY

08...

23...

JUN

05...

26...

AUG

*04...

*10...

*14...

*18...

21...

*24...

Streamflow, pH, Specific Temper- Hardness, . .

T. instan- onsite conductance, ature, total ,. . ,' Time . . . . , .. . ' . dissolved 

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

(ft3/*) units) (nS/cm) (°C) CaCO3) (m& '

1040

1315

1530

1150

1345

1050

0730

1300

1445

1015

1230

0720

1100

740

1,010

1,010

973

2,520

3,020

2,610

666

856

682

529

495

542

8.4

8.2

8.4

8.5

8.1

8.1

8.2

8.5

8.7

8.3

8.5

8.2

8.2

400

323

323

277

173

176

241

318

325

341

337

350

350

3.5

1.5

7.5

7.0

7.0

12.0

16.0

17.5

18.5

16.5

15.5

13.5

15.0

180

130

140

120

73

75

110

140

150

150

150

150

160

50.6

36.7

39.2

34.4

20.4

21.0

29.7

39.4

40.8

41.7

40.8

42.5

43.9

Magnesium, 

dissolved 

(mg/L)

13.1

9.38

10.1

9.19

5.38

5.41

7.56

10.8

10.9

11.2

11.2

11.8

11.9

Arsenic, 

dissolved

(Hg/L)

5.2

7.7

6.2

4.1

3.4

4.7

6.1

5.1

5.9

5.5

5.2

4.8

5.4

Date

NOV 2001

08...

MAR 2002

13...

APR

09...

MAY

08...

23...

JUN

05...

26...

AUG

*04...

*10...

*14...

*18...

21...

*24...

Arsenic, 

total 

recoverable

(Hg/L)

7

13

8

4

4

7

7

6

6

5

5

4

5

Cadmium, 

dissolved

Qifi/L)

<.l

E.I

<.l

<.l

E.04

E.02

.04

.06

E.02

E.02

E.02

E.02

E.02

Cadmium, 

total 

recoverable

(Hg/L)

<.l

.4

.1

<.l

.19

.14

.12

<.04

E.03

E.03

E.02

E.03

E.03

Copper, 

dissolved

(Hg/L)

El.l

8.4

5.0

2.2

2.9

3.2

4.3

2.2

2.6

2.3

2.0

1.7

2.5

Copper, 

total 

recoverable

(Hg/L)

5.7

53.6

25.3

5.8

23.3

20.8

18.0

3.3

4.3

4.1

4.1

3.5

6.4

Iron, 

dissolved

(Hg/L)

<10

71

20

E5

37

23

13

<10

<10

<10

<10

<10

<10

Iron, 

total 

recoverable

(Hg/L)

100

1,810

580

160

710

530

340

40

50

50

30

50

50

Lead, 

dissolved

(Hg/L)

<1

.29

.14

<.08

.10

.11

.08

E.05

<.08

<.08

<.08

<.08

<.08

Date

NOV 2001

08...

MAR 2002

13...

APR

09...

MAY

08...

23...

JUN

05...

26...

AUG

*04...

*10...

*14...

*18...

21...

*24...

Lead, 

total 

recoverable

(^g/L)

<1

11

4

<1

4

3

2

<1

<1

<1

<1

<1

<1

Manganese, 

dissolved

Oig/L)

3.3

18.0

7.4

5.2

6.1

6.6

9.2

1.2

.6

1.0

.5

4.8

.4

Manganese, 

total 

recoverable

(Hg/L)

28

239

85

24

91

71

54

10

12

13

9

15

13

Zinc, 

dissolved

(Hg/L)

3

12

4

2

4

4

4

3

2

3

1

-

4

Zinc, 

total 

recoverable

(Hg/L)

11

93

33

9

36

29

22

4

6

9

4

6

9

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

86

87

81

80

70

68

71

65

70

49

64

82

58

Sediment, 

suspended 

(mg/L)

7

129

36

10

45

35

22

4

4

5

5

6

4

Sediment 

discharge, 

suspended 

(ton/d)

14.0

352

98.2

26.3

306

285

155

7.2

9.2

9.2

7.1

8.0

5.9

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

TABLE 4 29
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2001 through September 2002 (Continued)

12340000-BLACKFOOT RIVER NEAR BONNER, MONT.

Date

NOV 2001

08...

APR 2002

09...

MAY

23...

JUN

05...

25...

AUG

21...

Streamflow,

_,. instan- Time taneous

(ft3/s)

1315 535

1730 1,310

1530 6,840

0910 6,720

1540 5,620

0845 694

pH, Specific Temper- Hardness, 

onsite conductance, ature, total 

(standard onsite water (mg/L as 

units) (nS/cm) (°C) CaCO3)

8.5 267 4.0 130

8.4 205 5.5 97

8.1 146 7.0 71

8.1 152 10.5 75

8.3 156 15.0 78

8.5 257 13.5 130

Calcium, 

dissolved

(mg/L)

33.5

24.7

18.6

19.6

20.2

33.0

Magnesium, 

dissolved 

(mg/L)

12.0

8.68

5.98

6.35

6.54

12.1

Arsenic, 

dissolved

1.0

1.5

.8

.8

.8

1.2

Date

NOV 2001

08...

APR 2002

09...

MAY

23...

JUN

05...

25...

AUG

21...

Arsenic, , . 

... Cadmium, total ,. . ' 

, , dissolved recoverable , ,, ,

(Hg/L) ^&L)

E2 <.l

El <.l

<2 <.04

<2 <.04

<2 <.04

El <.04

Cadmium, Copper,

total fr0PPer' total 

. , dissolved , , recoverable , _ . recoverable

(U2/L) (p,g/L) (ng/L)

<.l <1.0 E.5

<.l 1.5 3.8

.04 1.4 6.4

E.02 .9 3.9

<.04 .7 2.2

<.04 .4 .6

Iron, 

dissolved

<10

100

25

16

E9

<10

Iron, 

total 

recoverable

20

500

960

520

490

30

Lead, 

dissolved

<1

.11

<.08

<.08

<.08

<.08

Date

NOV 2001

08...

APR 2002

09...

MAY

23...

JUN

05...

25...

AUG

21...

Lead, Mangatotal nese, 

recoverable dissolved

<1 1.1

<1 5.2

1 2.8

<1 1.9

<1 2.4

<1 1.1

Manga- _. Zinc,

?e?e; * ?* tote1 total dissolved . . recoverable

E2 <1 <1

41 1 3

68 1 7

35 <1 4

31 <1 3

6 <1 <1

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

85

91

84

81

84

84

Sediment, 

suspended 

(mg/L)

1

28

81

47

44

3

Sediment 

discharge, 

suspended 

(ton/d)

1.4

99.0

1,500

853

668

5.6

30 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through September 2002 (Continued)

12340500-CLARK FORK ABOVE MISSOULA, MONT.

Date

NOV 2001

08...

MAR 2002

13...

APR

10...

MAY

08...

24...

JUN

05...

25...

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)

1500 854 8.4 349 4.0 160

1020 1,630 8.2 315 1.0 130

0830 2,450 8.3 262 6.5 120

1400 3,390 8.3 200 7.0 93

0815 7,890 8.0 160 7.0 75

0735 9,790 8.1 160 11.5 76

1350 7,730 8.2 180 15.5 82

Calcium, 

dissolved 

(mg/L)

43.3

36.7

31.7

24.6

20.2

20.4

21.8

Magnesium, 

dissolved 

(mg/L)

12.2

10.2

9.32

7.62

6.10

6.09

6.57

Arsenic, 

dissolved

3.5

5.6

3.7

1.8

1.8

2.1

2.3

Date

NOV 2001

08...

MAR 2002

13...

APR

10...

MAY

08...

24...

JUN

05...

25...

Arsenic, . . Cadmium, Copper, 

... Cadmium, ... Copper, , r. , total ,. , ' total ,. , ' total 

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

(Hg/L) ^ (Hg/L) (^ (Hg/L)

4 <.l <.l El.l 4.1

6 .2 E.I 5.4 17.3

4 <.l <.l 3.0 9.6

E2 <.l <.l 1.3 3.7

3 <.04 .09 1.5 13.9

4 <.04 .15 1.6 14.4

3 E.02 .05 1.6 6.3

Iron, 

dissolved

(Hg/L)

<10

35

58

13

29

22

11

Iron, 

total 

recoverable

(Hg/L)

70

450

360

140

800

670

400

Lead, 

dissolved

(Hg/L)

<1

.18

.17

<.08

E.04

E.07

E.05

Date

NOV 2001

08...

MAR 2002

13...

APR

10...

MAY

08...

24...

JUN

05...

25...

Lead, Manga- Manga- ^ 

... " nese, Zinc, . . ' total nese, . . : ,. . ' total 

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

tu<,n\ (,, an\ recoverable (^g/L) elian\ ^Llfi/AjJ ^Llfi/Aj^ , ._. ^U.2/1-'/

<1 9.4 17 2 7

3 16.5 61 8 31

2 24.4 49 2 13

<1 12.6 21 1 6

2 8.4 67 1 20

3 8.3 60 2 25

1 8.1 40 1 9

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

92

97

99

92

91

88

93

Sediment, 

suspended

(mg/L)

5

27

17

9

59

52

35

Sediment 

discharge, 

suspended 

(ton/d)

11.5

119

112

82.4

1,260

1,370

730

TABLE 4 31
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2001 through September 2002 (Continued)

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

Date

AUG 2002

*04...

*06...

*08...

*10...

*11...

*12...

*13...

*14...

*15...

*16...

*17...

*18...

*19...

*20...

21...

*23...

*24...

*29...

*31...

Streamflow, pH, Specific Temperrp. instan- onsite conductance, ature, 

taneous (standard onsite water 

(ft3/s) units) (nS/cm) (°C)

1430

1515

1300

1600

1130

1100

1245

0915

1030

1245

1130

1130

1100

1245

1040

1215

1200

1030

1900

1,470

1,740

1,750

1,800

1,680

1,620

1,560

1,490

1,410

1,350

1,300

1,250

1,230

1,200

1,200

1,280

1,240

1,220

835

8.4

8.4

8.2

8.3

8.2

8.1

8.2

8.2

8.2

8.2

8.1

8.2

8.2

8.2

8.3

8.2

8.2

8.2

8.4

274

273

280

288

293

292

293

288

289

290

290

289

289

291

292

293

294

298

300

17.5

17.0

14.5

17.5

17.0

17.0

18.0

17.0

16.5

17.0

15.5

16.0

15.5

16.0

14.5

15.0

16.0

16.5

18.0

Hardness, 

total 

(nig/Las 

CaC03)

130

130

130

130

140

140

140

130

130

130

140

140

130

140

140

140

140

140

140

Calcium, 

dissolved 

(mg/L)

33.4

34.3

34.4

35.7

37.0

36.1

35.9

35.1

34.1

35.4

35.8

35.5

34.4

35.5

35.8

36.3

36.9

36.5

37.1

Magnesium, 

dissolved

(mg/L)

11.0

10.9

10.7

11.0

11.3

11.1

11.2

11.3

10.9

11.2

11.5

11.5

11.2

11.6

11.6

11.5

11.8

11.7

11.8

Arsenic, 

dissolved

(Hg/L)

3.0

2.9

3.8

5.0

4.6

4.9

5.2

4.6

4.5

4.6

5.2

4.7

4.5

4.4

3.4

4.3

4.5

4.5

3.2

Date

AUG 2002

*04...

*06...

*08...

*10...

*11...

*12...

*13...

*14...

*15...

*16...

*17...

*18...

*19...

*20...

21...

*23...

*24...

*29...

*31...

Arsenic, 

total 

recoverable

(Hg/L)

3

3

4

8

8

13

10

9

7

8

10

9

8

9

8

6

6

7

3

Cadmium, 

dissolved

(Hg/L)

E.04

<.04

E.03

E.02

<.04

<.04

E.02

<.04

E.03

<.04

.04

E.03

E.03

<.04

<.04

E.03

E.03

E.03

E.02

Cadmium, 

total 

recoverable

Oig/L)

E.03

E.02

.23

.33

.42

.77

.63

.47

.33

.48

.60

.48

.42

.43

.40

.28

.29

.31

.09

Copper, 

dissolved

(Hg/L)

1.4

1.6

1.8

2.1

1.9

1.5

1.7

1.4

1.6

1.5

1.8

1.7

1.4

1.4

1.1

1.9

1.9

1.9

1.7

Copper, 

total 

recoverable

(Hg/L)

3.6

6.4

25.9

34.4

50.6

84.8

71.1

54.4

39.6

52.6

62.4

57.0

45.8

51.5

46.8

32.4

34.0

35.3

4.7

Iron, 

dissolved

(Hg/L)

<10

E6

11

E7

E8

17

14

15

E6

11

E9

E9

E10

13

15

<10

E5

E9

<10

Iron, 

total 

recoverable

(Hg/L)

70

110

570

830

1,300

2,130

1,880

1,460

1,050

1,350

1,570

1,370

1,190

1,210

1,170

890

880

950

110

Lead, 

dissolved

(Hg/L)

E.05

E.06

.11

.09

.12

.19

.15

.14

E.07

.13

.11

.12

.40

.19

.12

.13

.10

E.08

<.08

Date

AUG 2002

*04...

*06...

*08...

*10...

*11...

*12...

*13...

*14...

*15...

*16...

*17...

*18...

*19...

*20...

21...

*23...

*24...

*29...

*31...

Lead, 

total 

recoverable

(Hg/L)

<1

<1

4

6

9

15

13

9

7

9

11

10

8

9

8

6

6

6

<1

Manganese, 

dissolved

(Hg/L)

1.1

5.7

.7

.9

1.0

2.9

.9

1.2

.5

.9

.5

.6

.9

5.0

29.8

.4

.6

.6

.4

Manganese, 

total 

recoverable

(Vf/L)

20

29

81

80

102

162

144

113

87

103

121

108

93

97

92

67

69

83

21

Zinc, 

dissolved

(Hg/L)

1

1

4

5

6

5

7

4

6

5

10

7

5

5

2

7

7

7

4

Zinc, 

total 

recoverable

(Hg/L)

4

7

50

69

95

172

151

116

84

109

134

116

101

106

99

66

67

70

12

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

93

93

91

85

81

81

73

70

71

75

73

76

75

73

76

68

68

71

74

Sediment, 

suspended

(mg/L)

4

7

33

61

89

162

155

120

87

106

123

114

92

106

93

68

71

71

7

Sediment 

discharge, 

suspended 

(ton/d)

15.9

32.9

156

296

404

709

653

483

331

386

432

385

306

343

301

235

238

234

15.8

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

32 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through 

September 2002

[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)

96

95

93

87

110

127

124

145

153

155

157

160

162

168

178

176

176

177

176

185

182

178

177

174

175

175

174

172

172

173

176

4,828

156

185

87

Suspended sediment

Mean 

concentration 

(mg/L)

October

7

6

6

7

10

18

27

34

38

40

34

28

23

21

21

20

20

20

20

19

18

17

16

17

19

21

19

15

11

10

10

..

19

40

6

Discharge 

(ton/d)

1.8

1.5

1.5

1.6

3.0

6.2

9.1

13

16

17

14

12

10

9.5

10

9.5

9.5

9.5

9.5

9.5

8.8

8.2

7.6

8.0

9.0

9.9

8.9

7.0

5.1

4.7

4.8

255.7

8.2

17

1.5

Mean 

streamflow

(ft3/s)

177

177

176

175

175

174

175

175

177

175

174

175

176

177

175

172

172

180

177

180

180

181

180

177

179

184

185

160

164

192

-

5,296

176

192

160

Suspended sediment

Mean 

concentration 

(mg/L)

2001

November

10

10

10

11

14

15

15

12

10

10

10

11

12

12

13

14

14

15

15

16

16

15

14

13

12

11

9

7

6

6

--

12

16

6

Discharge 

(ton/d)

4.8

4.8

4.8

5.2

6.6

7.0

7.1

5.7

4.8

4.7

4.7

5.2

5.7

5.7

6.1

6.5

6.5

7.3

7.2

7.8

7.8

7.3

6.8

6.2

5.8

5.5

4.5

3.0

2.7

3.1

--

170.9

5.7

7.8

2.7

Mean 

streamflow

(ft3/s)

157

189

188

179

154

188

180

177

177

e!50

160

164

160

e!50

e!45

150

182

162

168

175

174

e!50

e!35

e!20

ellO

e95

e95

ellO

e!25

e!40

e!50

4,759

154

189

95

Suspended sediment

Mean 

concentration

(mg/L)

December

6

6

7

8

10

12

13

10

8

7

7

7

10

14

16

15

12

9

7

7

7

7

7

7

8

11

13

13

11

10

11

._

10

16

6

Discharge 

(ton/d)

2.5

3.1

3.6

3.9

4.1

6.1

6.3

4.8

3.8

2.8

3.0

3.1

4.3

5.7

6.3

6.1

5.9

3.9

3.2

3.3

3.3

2.8

2.6

2.3

2.4

2.8

3.3

3.9

3.7

3.8

4.5

121.2

3.9

6.3

2.3

TABLE 5 33
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 2001 through 

September 2002 (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)

e!50

e!40

e!40

e!50

e!60

170

191

201

186

e!65

e!60

e!70

178

173

176

176

171

167

157

162

e!60

e!55

e!50

160

174

176

e!60

e!40

e!20

e!30

e!40

5,008

162

201

120

Suspended sediment

Mean 

concentration

(mg/L)

January

13

15

16

17

17

17

29

37

34

31

28

26

25

27

27

26

23

19

16

13

12

12

12

12

12

12

12

12

12

13

17

..

19

37

12

Discharge 

(ton/d)

5.3

5.7

6.0

6.9

7.3

7.8

15

20

17

14

12

12

12

13

13

12

11

8.6

6.8

5.7

5.2

5.0

4.9

5.2

5.6

5.7

5.2

4.5

3.9

4.6

6.4

267.3

8.6

20

3.9

Mean 

streamflow

(ft3/s)

148

164

e!50

164

e!60

181

177

177

172

171

176

166

165

175

161

169

174

170

168

173

169

183

186

e!35

elOO

ellO

e!30

153

-

--

--

4,527

162

186

100

Suspended sediment

Mean 

concentration 

(mg/L)

2002

February

25

33

31

28

26

24

24

23

22

21

20

20

21

25

26

24

22

21

21

23

26

27

28

25

22

20

18

19

-

--

--

24

33

18

Discharge 

(ton/d)

10

15

13

12

11

12

11

11

10

9.7

9.5

9.0

9.4

12

11

11

10

9.6

9.5

11

12

13

14

9.1

5.9

5.9

6.3

7.8

-

--

--

290.7

10

15

5.9

Mean 

streamflow

(ft3/s)

e!50

e!50

162

176

182

181

170

e!50

e!60

169

195

220

210

203

192

193

182

180

186

183

160

189

191

204

208

199

212

202

200

199

199

5,757

186

220

150

Suspended sediment

Mean 

concentration 

(mg/L)

March

27

25

22

22

26

39

30

22

24

44

53

81

47

39

30

30

34

39

28

25

27

36

39

44

43

34

42

36

36

29

26

..

35

81

22

Discharge 

(ton/d)

11

10

9.6

10

13

19

14

8.9

10

20

28

48

27

21

16

16

17

19

14

12

12

18

20

24

24

18

24

20

19

16

14

552.5

18

48

8.9

34 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through 

September 2002 (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

(ftVs)

201

187

188

191

190

197

198

191

190

201

200

196

192

201

235

218

211

214

208

200

193

181

165

175

183

186

178

182

168

160

--

5,780

193

235

160

Suspended sediment

Mean 

concentration

(mg/L)

April

28

42

40

37

38

39

35

26

27

30

30

28

32

36

32

27

23

26

24

23

21

18

20

18

20

16

13

13

14

12

--

..

26

42

12

Discharge 

(ton/d)

15

21

20

19

19

21

19

13

14

16

16

15

17

20

20

16

13

15

13

12

11

8.8

8.9

8.5

9.9

8.0

6.2

6.4

6.4

5.2

--

413.3

14

21

5.2

Mean 

streamflow

(ft3/s)

156

155

147

147

127

131

136

140

125

127

131

126

118

109

100

85

83

74

76

83

120

191

197

185

163

144

139

147

145

175

278

4,260

137

278

74

Suspended sediment

Mean 

concentration 

(mg/L)

2002

May

15

14

10

9

16

12

15

12

11

12

7

6

7

8

9

11

8

5

5

5

12

42

28

19

16

12

10

10

10

20

94

15

94

5

Discharge 

(ton/d)

6.3

5.8

4.0

3.6

5.5

4.2

5.5

4.5

3.7

4.1

2.5

2.0

2.2

2.4

2.4

2.5

1.8

1.0

1.0

1.1

3.9

22

15

9.5

7.0

4.7

3.7

4.0

3.9

9.4

71

220.2

7.1

71

1.0

Mean 

streamflow

(frVs)

287

363

389

311

273

252

251

263

296

429

388

308

278

243

236

248

284

325

344

293

258

286

339

322

286

260

251

232

239

246

--

8,780

293

429

232

Suspended sediment

Mean 

concentration

(mg/L)

Jnne

52

59

128

68

50

39

29

25

26

54

52

29

22

21

21

21

24

27

16

12

14

19

26

20

13

10

9

9

10

10

--

30

128

9

Discharge 

(ton/d)

40

58

134

57

37

27

20

18

21

62

54

24

17

14

13

14

18

24

15

9.5

9.8

15

24

17

10

7.0

6.1

5.6

6.5

6.6

--

784.1

26

134

5.6

TABLE 5 35
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 2001 through 

September 2002 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(frVs)

219

195

181

182

171

160

157

158

147

134

116

104

97

87

81

78

77

74

69

78

76

66

62

69

71

73

83

90

83

72

69

3,379 

109

219

62

Suspended sediment

Mean 

concentration

(mg/L)

July

9

7

6

7

7

7

7

6

5

5

4

4

3

3

3

3

3

4

4

5

5

6

6

6

6

6

7

8

9

9

11

6

11

3

Discharge 

(ton/d)

5.3

3.7

2.9

3.4

3.2

3.0

3.0

2.6

2.0

1.8

1.3

1.1

.79

.70

.65

.63

.62

.80

.75

1.1

1.0

1.1

1.0

1.1

1.1

1.2

1.6

1.9

2.0

1.8

2.1

55.24 

1.8

5.3

.62

Mean 

streamflow

(ft3/s)

63

60

59

66

77

81

82

135

168

140

116

106

92

82

73

74

72

70

66

65

77

103

113

110

100

102

99

103

106

104

99

2,863 

92

168

59

Suspended sediment

Mean 

concentration 

(mg/L)

2002

August

15

15

12

7

4

3

3

3

2

2

2

2

2

2

2

3

4

3

1

2

4

4

2

2

2

2

2

2

2

2

2

4

15

1

Discharge 

(ton/d)

2.5

2.4

1.9

1.2

.83

.66

.67

1.1

.91

.76

.62

.57

.50

.44

.39

.60

.78

.57

.18

.35

.84

1.1

.61

.60

.54

.55

.54

.56

.57

.56

.53

24.93 

.80

2.5

.18

Mean 

streamflow

(ft3/s)

99

99

100

97

89

90

132

142

129

119

117

115

115

115

111

111

112

126

129

123

113

115

118

106

103

112

124

132

130

132

--

3,455 

115

142

89

Suspended sediment

Mean 

concentration

(mg/L)

September

3

3

3

3

3

3

7

8

7

6

6

6

5

4

4

4

5

7

7

7

7

5

4

5

8

10

10

10

10

10

--

6

10

3

Discharge 

(ton/d)

.80

.81

.81

.78

.72

.73

2.5

3.1

2.4

1.9

1.9

1.9

1.6

1.2

1.2

1.2

1.5

2.4

2.4

2.3

2.1

1.5

1.3

1.4

2.2

3.0

3.4

3.6

3.5

3.6

--

57.75 

1.9

3.6

.72

TOTAL FOR WATER YEAR 2002:

STREAMFLOW-58,692 ft3/s 

SEDIMENT DISCHARGE--3,213.82 tons

36 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through 

September 2002

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

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/s)

474

478

485

486

491

518

547

555

567

591

619

644

681

730

788

782

764

748

771

814

820

806

814

811

788

773

772

788

805

818

822

21,350

689

822

474

Suspended sediment

Mean 

concentration

(mg/L)

October

5

6

7

7

8

9

11

13

14

15

15

16

18

20

22

22

21

20

19

18

16

13

11

10

11

11

11

11

11

12

14

..

13

22

5

Discharge 

(ton/d)

6.4

7.8

9.2

9.2

11

13

16

19

21

24

25

28

33

39

47

46

43

40

40

40

35

28

24

22

23

23

23

23

24

26

31

799.6

26

47

6.4

Mean 

streamflow

(ft3/s)

854

847

822

800

789

776

770

761

736

725

718

706

720

728

724

722

717

722

728

721

720

728

728

713

708

697

686

660

618

676

--

22,020

734

854

618

Suspended sediment

Mean 

concentration 

(mg/L)

2001

November

14

13

12

10

9

9

8

7

7

7

7

6

6

6

6

6

6

7

7

7

8

7

7

6

6

6

6

6

6

6

--

..

7

14

6

Discharge 

(ton/d)

32

30

27

22

19

19

17

14

14

14

14

11

12

12

12

12

12

14

14

14

16

14

14

12

11

11

11

11

10

11

--

456

15

32

10

Mean 

streamflow

(ft3/s)

697

655

699

697

631

615

671

656

635

643

590

577

588

683

637

574

654

611

589

615

631

656

596

489

e350

e250

e200

e220

e250

e350

e500

17,209

555

699

200

Suspended sediment

Mean 

concentration

(mg/L)

December

7

7

8

8

7

7

7

6

6

6

6

5

6

7

7

8

7

6

5

5

5

4

4

4

3

3

4

6

8

10

10

_

6

10

3

Discharge 

(ton/d)

13

12

15

15

12

12

13

11

10

10

9.6

7.8

9.5

13

12

12

12

9.9

7.9

8.3

8.5

7.1

6.4

5.3

2.8

2.0

2.2

3.6

5.4

9.5

14

291.8

9.4

15

2.0

TABLE 6 37
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 2001 through 

September 2002 (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)

e480

e450

495

559

616

612

631

743

830

774

699

713

713

686

640

597

598

600

561

586

596

594

556

541

613

655

615

549

475

494

511

18,782

606

830

450

Suspended sediment

Mean 

concentration

(mg/L)

January

9

7

7

7

7

6

7

15

21

15

8

8

9

8

8

7

7

7

8

7

6

6

7

7

7

7

6

5

5

4

7

8

21

4

Discharge 

(ton/d)

12

8.5

9.4

11

12

9.9

12

30

47

31

15

15

17

15

14

11

11

11

12

11

9.7

9.6

11

10

12

12

10

7.4

6.4

5.3

9.7

417.9

13

47

5.3

Mean 

streamflow

(ft3/s)

542

587

554

557

573

554

604

648

619

592

614

595

560

572

572

558

582

613

596

598

597

652

774

732

e500

e300

e400

e550

-

--

16,195

578

774

300

Suspended sediment

Mean 

concentration

(mg/L)

2002

February

8

8

9

9

9

9

9

10

10

9

9

9

9

8

8

7

8

9

10

10

11

13

21

20

16

16

16

15

-

--

--

..

11

21

7

Discharge 

(ton/d)

12

13

13

14

14

13

15

18

17

14

15

14

14

12

12

11

13

15

16

16

18

23

44

40

22

13

17

22

-

--

--

480

17

44

11

Mean 

streamflow

(ft3/s)

e600

e550

e480

507

562

651

596

512

494

548

617

874

1,040

900

807

750

e700

603

661

e650

e500

e520

642

782

899

939

1,080

1,030

928

889

916

22,227

717

1,080

480

Suspended sediment

Mean 

concentration 

(mg/L)

March

14

11

7

7

11

13

14

13

11

14

16

80

130

46

26

18

19

15

16

20

24

19

22

36

86

76

112

99

46

34

31

35

130

7

Discharge 

(ton/d)

23

16

9.1

9.6

17

23

23

18

15

21

27

189

364

112

57

36

36

24

29

35

32

27

38

76

209

193

326

275

115

82

77

2,533.7

82

364

9.1

38 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through 

September 2002 (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/*)

el, 000

e950

846

813

841

1,020

1,260

1,160

1,060

1,070

1,110

1,130

1,150

1,290

1,690

1,630

1,430

1,300

1,210

1,130

1,100

1,080

1,050

1,050

1,000

994

1,000

1,000

974

968

--

33,306

1,110

1,690

813

Suspended sediment

Mean 

concentration

(mg/L)

April

53

80

29

28

31

63

135

94

44

38

40

46

42

58

126

66

42

26

22

20

22

17

15

11

11

15

18

15

15

15

--

__

41

135

11

Discharge 

(ton/d)

143

205

66

61

70

173

459

293

126

110

120

140

131

202

576

291

162

92

72

61

65

49

43

31

30

40

49

41

39

39

--

3,979

133

576

30

Mean 

streamflow

(ft3/s)

986

999

1,050

1,090

1,070

1,080

1,060

994

937

894

874

841

822

873

953

984

966

994

1,130

1,450

1,980

2,610

2,570

2,250

2,000

1,940

2,110

2,320

2,620

3,060

3,500

47,007

1,516

3,500

822

Suspended sediment

Mean 

concentration 

(mg/L)

2002

May

15

15

18

18

16

14

12

10

9

8

8

8

10

11

12

10

10

10

17

42

74

81

44

28

23

21

21

27

39

65

91

_

25

91

8

Discharge 

(ton/d)

40

40

51

53

46

41

34

27

23

19

19

18

22

26

31

27

26

27

52

164

395

572

305

170

124

110

119

169

275

537

860

4,422

143

860

18

Mean 

streamflow

(ft3/s)

3,490

3,590

3,790

3,400

3,010

2,900

2,770

2,580

2,600

3,000

3,250

2,940

2,740

2,650

2,700

2,810

3,210

3,720

3,800

3,490

3,070

2,930

3,150

3,040

2,780

2,580

2,400

2,400

2,390

2,440

--

89,620

2,987

3,800

2,390

Suspended sediment

Mean 

concentration 

(mg/L)

June

71

63

84

56

35

29

26

25

26

38

51

38

29

26

26

32

33

39

37

28

23

25

31

28

22

21

21

18

18

17

--

__

34

84

17

Discharge 

(ton/d)

668

610

858

514

284

227

194

174

183

308

448

301

214

186

189

242

286

391

379

264

191

198

264

230

165

147

136

117

116

112

--

8,596

287

858

112

TABLE 6 39
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 2001 through 

September 2002 (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)

2,310

2,140

2,010

1,910

1,840

1,620

1,270

1,280

1,260

1,190

1,120

1,070

1,020

975

972

1,070

1,030

976

990

1,040

1,000

949

917

903

878

885

919

868

830

799

751

36,792

1,187

2,310

751

Suspended sediment

Mean 

concentration

(mg/L)

July

14

12

9

8

6

7

7

8

7

5

5

4

4

4

4

4

4

4

4

5

6

7

6

6

5

5

5

4

4

4

4

6

14

4

Discharge 

(ton/d)

87

69

49

41

30

31

24

28

24

16

15

12

11

11

11

12

11

11

11

14

16

18

15

15

12

12

12

9.4

9.0

8.6

8.1

653.1

21

87

8.1

Mean 

streamflow

(ft3/s)

705

686

653

652

727

728

718

782

865

862

809

745

700

668

638

597

557

524

508

495

513

548

557

545

559

556

546

552

556

573

582

19,706

636

865

495

Suspended sediment

Mean 

concentration 

(mg/L)

2002

August

4

4

4

4

6

5

4

4

6

4

4

4

4

5

5

5

5

5

4

5

6

5

4

4

3

4

4

4

4

4

4

4

6

3

Discharge 

(ton/d)

7.6

7.4

7.1

7.0

12

9.8

7.8

8.4

14

9.3

8.7

8.0

7.6

9.0

8.6

8.1

7.5

7.1

5.5

6.7

8.3

7.4

6.0

5.9

4.5

6.0

5.9

6.0

6.0

6.2

6.3

235.7

7.6

14

4.5

Mean 

streamflow

(ft3/s)

572

558

544

541

541

549

611

661

689

677

653

627

605

582

572

562

560

573

585

586

554

545

546

551

553

548

566

587

601

625

--

17,524

584

689

541

Suspended sediment

Mean 

concentration

(mg/L)

September

5

5

5

5

5

5

5

5

5

5

4

4

4

4

4

4

4

4

4

4

3

3

3

3

2

2

2

2

2

2

--

4

5

2

Discharge 

(ton/d)

7.7

7.5

7.3

7.3

7.3

7.4

8.2

8.9

9.3

9.1

7.1

6.8

6.5

6.3

6.2

6.1

6.1

6.2

6.3

6.3

4.5

4.4

4.4

4.5

3.0

3.0

3.1

3.2

3.2

3.4

--

180.6

6.0

9.3

3.0

TOTAL FOR WATER YEAR 2002:

STREAMFLOW-361,738 ft3/s 

SEDIMENT DISCHARGE--23,045.4 tons

40 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through 

September 2002

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

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/s)

856

860

861

856

874

899

930

949

963

980

1,030

1,060

1,110

1,160

1,210

1,200

1,180

1,120

1,190

1,230

1,230

1,230

1,240

1,250

1,250

1,230

1,220

1,240

1,270

1,310

1,310

34,298

1,106

1,310

856

Suspended sediment

Mean 

concentration 

(mg/L)

October

4

4

7

7

7

6

6

5

6

6

6

7

7

7

7

7

7

7

7

7

7

7

6

6

6

6

6

6

7

6

6

..

6

7

4

Discharge 

(ton/d)

9.2

9.3

16

16

17

15

15

13

16

16

17

20

21

22

23

23

22

21

23

23

23

23

20

20

20

20

20

20

24

21

21

589.5

19

24

9.2

Mean 

streamflow

(ft3/s)

1,400

1,340

1,310

1,300

1,290

1,280

1,260

1,220

1,230

1,210

,190

,190

,190

,190

,190

1,170

1,190

1,180

1,170

1,170

1,190

1,220

1,210

1,220

1,180

1,170

1,150

1,120

1,030

1,110

--

36,270

1,209

1,400

1,030

Suspended sediment

Mean 

concentration 

(mg/L)

2001

November

6

6

6

6

6

5

5

5

6

6

6

5

5

5

5

5

5

6

6

6

6

5

4

3

3

4

4

4

4

4

--

5

6

3

Discharge 

(ton/d)

23

22

21

21

21

17

17

17

20

20

19

16

16

16

16

16

16

19

19

19

19

16

13

9.9

9.6

13

12

12

11

12

--

498.5

17

23

9.6

Mean 

streamflow

(ft3/s)

1,130

1,100

1,120

1,130

1,070

1,050

1,100

1,110

1,050

1,010

1,020

991

1,010

1,150

1,060

967

1,070

988

936

e950

el,050

1,090

1,010

e850

e750

e650

e600

e550

e700

e850

el,000

30,112

971

1,150

550

Suspended sediment

Mean 

concentration

(mg/L)

December

4

4

4

4

4

4

5

5

4

4

4

3

3

3

3

3

3

3

2

2

2

2

2

2

2

3

3

3

4

3

2

..

3

5

2

Discharge 

(ton/d)

12

12

12

12

12

11

15

15

11

11

11

8.0

8.2

9.3

8.6

7.8

8.6

8.0

5.1

5.1

5.7

5.9

5.4

4.6

4.0

5.3

4.9

4.5

7.6

6.9

5.4

262.9

8.5

15

4.0

TABLE 7 41
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 2001 through 

September 2002 (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)

el, 000

e900

e900

e 1,000

el, 100

el, 100

1,100

1,210

1,300

1,250

1,160

1,160

1,160

1,120

1,060

1,020

1,020

1,010

978

1,010

1,040

1,030

986

962

1,050

1,100

1,060

935

903

896

981

32,501

1,048

1,300

896

Suspended sediment

Mean 

concentration

(mg/L)

January

2

5

6

5

4

4

5

5

5

5

4

4

3

3

3

3

3

3

3

3

3

4

4

4

4

5

4

4

4

3

2

4

6

2

Discharge 

(ton/d)

5.4

12

15

14

12

12

15

16

18

17

13

13

9.4

9.1

8.6

8.3

8.3

8.2

7.9

8.2

8.4

11

11

10

11

15

11

10

9.8

7.3

5.3

340.2

11

18

5.3

Mean 

streamflow

(ft3/s)

1,020

1,030

953

953

982

965

1,060

1,100

1,130

965

1,070

985

953

978

887

937

964

1,060

1,030

1,010

980

1,050

1,220

1,110

859

e650

882

1,010

-

--

--

27,793

993

1,220

650

Suspended sediment

Mean 

concentration

(mg/L)

2002

February

2

2

3

3

3

4

5

7

8

7

6

5

5

4

3

3

4

4

5

5

5

6

7

8

8

8

8

6

-

--

--

5

8

2

Discharge 

(ton/d)

5.5

5.5

7.7

7.7

8.0

10

14

21

24

18

17

13

13

11

7.2

7.6

10

11

14

14

13

17

23

24

19

14

19

16

-

--

--

384.2

14

24

5.5

Mean 

streamflow

(ft3/s)

1,030

1,000

948

1,030

1,060

1,060

923

885

976

996

1,120

1,280

1,620

1,420

1,340

1,240

1,170

1,020

1,110

1,110

886

962

1,150

1,280

1,400

1,460

1,600

1,730

1,640

1,580

1,640

37,666

1,215

1,730

885

Suspended sediment

Mean 

concentration 

(mg/L)

March

3

3

3

3

5

4

3

4

4

5

7

11

24

16

10

8

7

7

8

8

4

4

7

9

12

17

21

29

16

13

12

9

29

3

Discharge 

(ton/d)

8.3

8.1

7.7

8.3

14

11

7.5

9.6

11

13

21

38

105

62

36

27

22

19

24

24

9.6

10

22

31

45

67

91

135

71

56

53

1,067.1

34

135

7.5

42 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2001 through 

September 2002 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/*)

1,900

2,000

1,640

1,560

1,570

1,910

2,650

2,590

2,410

2,350

2,530

2,710

3,000

3,910

5,220

5,200

4,710

4,340

3,920

3,600

3,460

3,340

3,310

3,360

3,220

3,150

3,120

3,070

2,990

2,980

--

91,720

3,057

5,220

1,560

Suspended sediment

Mean 

concentration 

(mg/L)

April

15

21

17

14

12

14

29

38

25

18

16

16

19

22

38

30

24

22

13

11

11

9

10

7

6

6

7

8

8

7

--

..

16

38

6

Discharge 

(ton/d)

77

113

75

59

51

72

207

266

163

114

109

117

154

232

535

421

305

258

138

107

103

81

89

64

52

51

59

66

64

56

--

4,258

142

535

51

Mean 

streamflow

(ft3/s)

3,060

3,240

3,610

3,910

3,870

3,800

3,640

3,410

3,190

2,940

2,840

2,670

2,730

3,160

3,770

3,960

3,930

4,100

4,670

6,480

9,060

10,400

9,650

8,300

7,260

6,730

6,960

7,690

8,810

10,400

11,400

169,640

5,472

11,400

2,670

Suspended sediment

Mean 

concentration

(mg/L)

2002

May

8

9

9

10

10

9

9

8

7

7

6

7

5

7

10

10

10

11

15

40

102

97

73

49

36

29

26

31

46

84

94

28

102

5

Discharge 

(ton/d)

66

79

88

106

104

92

88

74

60

56

46

51

37

60

102

107

106

122

189

700

2,490

2,720

1,900

1,100

705

527

488

643

1,090

2,360

2,880

19,236

621

2,880

37

Mean 

streamflow

(frVs)

11,500

11,400

11,200

10,400

9,650

9,520

9,400

8,890

8,420

8,490

8,360

7,580

7,060

6,920

7,410

8,210

9,090

9,640

9,430

8,470

7,480

7,190

7,870

8,210

7,740

7,280

6,900

6,880

6,770

6,620

--

253,980

8,466

11,500

6,620

Suspended sediment

Mean 

concentration

(mg/L)

June

96

79

68

57

47

41

37

37

31

30

35

34

27

24

25

35

48

58

55

43

30

25

28

53

37

27

25

27

21

19

--

._

40

96

19

Discharge 

(ton/d)

2,970

2,420

2,050

1,610

1,230

1,050

939

888

705

688

790

696

515

449

500

776

1,180

1,510

1,400

983

606

485

595

1,180

773

531

466

501

384

340

--

29,210

974

2,970

340

TABLE 7 43
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 2001 through 

September 2002 (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)

6,030

5,430

4,850

4,580

4,220

3,970

3,730

3,700

3,690

3,450

3,240

2,970

2,840

2,680

2,570

2,630

2,580

2,380

2,360

2,380

2,240

2,180

2,120

2,090

2,020

2,030

2,050

1,980

1,890

1,860

1,740

92,480

2,983

6,030

1,740

Suspended sediment

Mean 

concentration

(mg/L)

July

16

15

13

10

10

8

8

6

5

5

5

5

6

6

6

6

6

5

12

17

15

13

12

10

9

7

7

6

6

5

5

..

9

17

5

Discharge 

(ton/d)

260

220

170

124

114

86

81

60

50

47

44

40

46

43

42

43

42

32

76

109

91

77

69

57

49

38

39

32

31

25

23

2,260

73

260

23

Mean 

streamflow

(ft3/s)

1,680

1,610

1,560

1,500

1,750

1,780

1,730

1,750

1,800

1,780

1,680

1,600

1,530

1,460

1,400

1,350

1,300

1,250

1,230

1,200

1,210

1,260

1,270

1,230

1,230

1,230

1,200

1,210

1,210

1,120

1,010

44,120

1,423

1,800

1,010

Suspended sediment

Mean 

concentration 

(mg/L)

2002

August

5

5

4

4

10

8

15

32

49

59

92

155

154

114

90

106

121

111

94

103

92

80

70

70

66

56

52

59

71

34

8

64

155

4

Discharge 

(ton/d)

23

22

17

16

47

38

70

151

239

283

418

672

635

449

340

386

425

376

311

334

299

272

239

232

220

186

169

192

233

103

22

7,419

239

672

16

Mean 

streamflow

(ft3/s)

1,090

1,160

1,160

1,080

1,080

1,140

1,230

1,270

1,320

1,300

1,260

1,210

1,170

1,150

1,110

1,120

1,110

1,110

1,150

1,150

1,120

1,100

1,060

1,060

1,060

1,060

1,060

1,090

1,090

1,160

--

34,230

1,141

1,320

1,060

Suspended sediment

Mean 

concentration

(mg/L)

September

7

7

7

6

6

8

10

11

9

8

7

5

5

6

6

6

6

8

9

9

9

8

8

7

7

9

10

10

10

10

--

__

8

11

5

Discharge 

(ton/d)

21

22

22

18

17

25

33

38

32

28

24

16

16

19

18

18

18

24

28

28

27

24

23

20

20

26

29

29

29

31

--

723

24

38

16

TOTAL FOR WATER YEAR 2002:

STREAMFLOW-884,810 ft3/s 

SEDIMENT DISCHARGE-66,248.4 tons

44 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

[Abbreviations: E, estimated; |0,g/L, micrograms per liter; mg/L, milligrams per liter; mm, millimeter. Symbol: <, less than minimum reporting level]

Station 

number

12323800

12324200

12323230

Station name

Clark Fork near Galen

Clark Fork near Galen

Clark Fork at Deer Lodge

Clark Fork at Deer Lodge

Date Time

11-06-01 1640

11-06-01 1645

03-14-02 1330

03-14-02 1335

Blacktail Creek at Harrison Avenue, at Butte 04-08-02 0900

Blacktail Creek at Harrison Avenue, at Butte 04-08-02 0905

12334550

12340500

12323600

12331800

Clark Fork at Turah Bridge, near Bonner

Clark Fork at Turah Bridge, near Bonner

Clark Fork above Missoula

Clark Fork above Missoula

Silver Bow Creek at Opportunity

Silver Bow Creek at Opportunity

Clark Fork near Drummond

Clark Fork near Drummond

05-08-02 1150

05-08-02 1155

05-24-02 0815

05-24-02 0820

06-03-02 1915

06-03-02 1920

08-21-02 1435

08-21-02 1440

Hardness, Calcium, Magnesium, Arsenic, 

total ,. . , ,. . ,. . , 

, dissolved dissolved dissolved (mg/L as . , , n \ f n \ /- rc\ \ (mg/L) (mg/L) (Hg/L) CaCU3)

210

210

240

250

90

88

120

120

75

76

130

130

260

270

61.4

61.8

71.9

73.1

25.6

24.8

34.4

34.7

20.2

20.3

38.4

39.1

73.7

75.1

14.0 10.4

13.8 10.6

15.6 10.1

15.8 9.9

6.41 3.3

6.23 3.4

9.19 4.1

9.23 4.2

6.10 1.8

6.10 1.8

7.21 11.3

7.36 11.7

18.3 11.3

18.9 11.3

Arsenic, 

total 

recoverable

13

13

14

14

4

5

4

4

3

2

21

22

10

10

Station 

number

12323800

12324200

12323230

12334550

12340500

12323600

12331800

Cadmium, 

Date dissolved

(Hg/L)

11-06-01 <0.1

11-06-01 <.l

03-14-02 <.l

03-14-02 <.l

04-08-02 .1

04-08-02 E.I

05-08-02 <.l

05-08-02 <.l

05-24-02 <.04

05-24-02 <.04

06-03-02 .38

06-03-02 .38

08-21-02 E.03

08-21-02 E.03

Cadmium, _

total HC°pPer' 

, , dissolved recoverable , ~ ,

(Hg/L) (llg/

<0.1 2.3

<.l 2.4

.2 7.2

.2 7.5

<.l 4.8

<.l 4.9

<.l 2.2

<.l 2.0

.09 1.5

.10 1.6

1.34 31.5

1.32 31.9

.04 3.0

.04 3.0

Copper, 

total 

recoverable

(Hg/L)

5.1

5.0

44.8

42.9

9.2

9.0

5.8

5.8

13.9

12.1

154

154

4.9

4.9

Iron, 

dissolved

(Hg/L)

<10

<10

E10

E9

231

231

E5

E6

29

30

45

46

<10

<10

Iron, 

total 

recoverable

(Hg/L)

70

70

700

700

860

870

160

150

800

790

1,140

1,180

40

40

Lead, 

dissolved

(ug/L)

<1

<1

.09

.09

.23

.25

<.08

<.08

E.04

E.06

.88

.86

<.08

E.05

Station 

number

12323800

12324200

12323230

12334550

12340500

12323600

12331800

Lead,

Date t0tal K, recoverable

11-06-01 <1

11-06-01 <1

03-14-02 6

03-14-02 6

04-08-02 2

04-08-02 1

05-08-02 <1

05-08-02 <1

05-24-02 2

05-24-02 2

06-03-02 32

06-03-02 32

08-21-02 <1

08-21-02 <1

, Manganese, Manganese, .

dissolved total . , 

, , recoverable

41.2 65

42.2 65

50.1 157

50.9 159

144 173

149 172

5.2 24

5.3 23

8.4 67

8.3 67

234 439

234 443

10.9 23

10.9 22

Zinc, 

dissolved

2

2

13

14

4

4

2

3

1

1

95

97

3

3

Zinc, 

total 

recoverable

5

5

44

43

8

8

9

9

20

20

287

296

6

6

Sediment, 

suspended, 

diameter, 

percent finer 

than 0.062 mm

71

70

72

72

80

81

80

77

91

90

74

73

67

69

Sediment, 

suspended

(mg/L)

4

3

39

38

15

15

10

11

59

60

35

37

4

4

TABLE 8 45
Table 9. Precision of chemical and suspended-sediment analyses of field replicates for water 

samples, upper Clark Fork basin, Montana

[Abbreviations: Hg/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, Jig/L

Arsenic, dissolved, |ig/L

Cadmium, total recoverable, jig/L

Cadmium, dissolved, |ig/L

Copper, total recoverable, |ig/L

Copper, dissolved, jig/L

Iron, total recoverable, |ig/L

Iron, dissolved, |ig/L

Lead, total recoverable, |ig/L

Lead, dissolved, |ig/L

Manganese, total recoverable, jig/L

Manganese, dissolved, jig/L

Zinc, total recoverable, |ig/L

Zinc, dissolved, jig/L

Sediment, suspended, mg/L

Sediment, suspended, percent finer than 0.062 mm

Number of 

replicate pairs

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

Standard 

deviation, 

in units (+/-)

0.58

.19

.46

.14

.01

.0

.70

.15

12

.54

.27

.01

1.3

1.4

2.4

.66

.76

1.1

Relative 

standard 

deviation, 

in percent (+/-)

1.2

1.7

4.7

1.8

2.3

.0

2.1

2.0

2.2

1.1

4.4

3.7

.94

1.9

4.4

3.8

3.2

1.4

46 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

[Abbreviations: M-g/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, |Xg/L

Cadmium, dissolved, jig/L

Copper, total recoverable, (ig/L

Copper, dissolved, (ig/L

Iron, total recoverable, jig/L

Iron, dissolved, (ig/L

Lead, total recoverable, (ig/L

Lead, dissolved, |ig/L

Manganese, total recoverable, (ig/L

Manganese, dissolved, jig/L

Zinc, total recoverable, jig/L

Zinc, dissolved, jig/L

Number of 

replicate pairs

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

Standard 

deviation,1 

in units (+/-)

0.42

.08

.60

.12

.02

.02

.32

.10

2.8

1.7

.04

.01

.45

.59

.15

.05

Relative 

standard 

deviation, 

in percent (+/-)

1.2

.91

6.6

1.5

25

33

2.5

3.2

.60

2.9

1.6

11

.43

1.2

1.2

1.5

Within limits of 

data-quality 

objective

Yes

Yes

Yes

Yes

Yes2

Yes2

Yes

Yes

Yes

Yes

Yes

Yes

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 (maximum relative standard deviation of 20 percent) results 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.

TABLE 10 47
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, jig/L 

Arsenic, dissolved, (ig/L 

Cadmium, total recoverable, [ig/L 

Cadmium, dissolved, |ig/L 

Copper, total recoverable, jig/L 

Copper, dissolved, (ig/L 

Iron, total recoverable, jig/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, jig/L 

Zinc, dissolved, (ig/L

93.0-103 

95.8-114 

96.3-98.9 

98.8-103 

96.7-101 

95.0-104 

89.3-101 

93.0-112 

90.5-103 

89.9-107 

95.4-102 

88.8-104 

91.8-105 

94.4-113

97.9

105.1

97.6

101.1

98.8

99.4

95.1

102.3

96.9

98.5

98.5

96.5

98.3

103.9

Yes 

Yes 

Yes

Yes 

Yes

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes

48 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

[Abbreviation: 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, |ig/L 

Arsenic, dissolved, |ig/L 

Cadmium, total recoverable, (ig/L 

Cadmium, dissolved, (ig/L 

Copper, total recoverable, jig/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

86.0-114 

97.1-114 

98.6-105 

97.5-114 

92.9-101 

91.2-103 

83.3-102 

103-111 

92.2-106 

91.9-111 

92.5-104 

88.4-100 

89.9-102 

92.6-110

99.9

105.8

102.0

106.0

96.9

97.3

92.6

107.1

98.9

101.4

98.3

94.3

95.8

101.3

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes

TABLE 12 49
Table 13. Chemical analyses of field blanks for water samples

[Abbreviations: °C, degrees Celsius; E, estimated; Hg/L, micrograms per liter; |0,S/cm, microsiemens per centimeter at 25 °C; mg/L, milligrams per liter. 

Symbol: <, less than laboratory reporting level]

P"; conduct- Calcium, M.a8ne' Arsenic, ^otaT Cadmium, Cadmium, 

Date Time /sJJ3£d ance' dissolved d^T'ed dissolved recov- dissolved reaSSaWe

units> r,?^ (mg/L) tos/D (Rg/L) nSfl (Rg/L) <Hg<L) ^jjAj/Lin^ V.P'&'J-'/

NOV 2001

07... 0630 5.6 2 <0.01 <0.008 <0.2 <2 <0.1 <0.1

MAR 2002

13... 1100 5.6 2 <.01 <.008 <.2 <2 E.I <.l

APR

09... 1500 5.6 2 <.01 <.008 <.2 <2 <.l <.l

MAY

08... 1330 5.6 2 <.01 <.008 <.2 <2 <.l <.l

30... 1030 5.7 2 <.01 <.008 <.2 <2 <.04 <.04

JUN

04... 0930 5.6 2 E.01 <.008 <.2 <2 <.04 <.04

24... 1700 5.7 2 <.01 <.008 <.2 <2 <.04 <-04

AUG

20... 2100 5.6 2 .03 .009 <.2 <2 <.04 <.04

Copper, 

dissolved

((ig/L)

<1.0

<1.0

<1.0

<1.0

<.2

<.2

<2

<.2

C2Sr' Iron' SX Lead' VT!' Manganese, ^es?" Zinc, 

Date reco^able dj^f reco^ab.e -Jgf rentable *Jg- ^^Lbte "f

NOV 2001

07... <0.6 <10 <10 <1 <1 <0.1 <2.4 <1

MAR 2002

13... <6 <10 <10 <.08 <1 <.l <2.4 <1

APR

09... <.6 <10 <10 <.08 <1 <.l <2.4 <1

MAY

08... <.6 <10 <10 <.08 <1 <.l <2.4 <1

30... <.6 <10 <10 <.08 <1 <.l <1 <1

JUN

04... <.6 <10 <10 <.08 <1 <.l <1 <1

24... <.6 <10 <10 <.08 <1 <.l <1 <1

AUG

20... <.6 <10 <10 <.08 <1 E.I <1 <1

Zinc, 

total 

recoverable

(Rg/L)

1

<1

<1

<1

<1

<1

<1

<1

50 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

upper Clark Fork Basin, Montana
Table 14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, August 2002

[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]

Station number 

(fig. 1)

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Warm Springs Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, 

near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek 

diversion, near Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, 

near Bonner

Clark Fork above Missoula

Clark Fork below Missoula 1

Number 

of composite 

samples

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

Concentration, in |ag/g

Cadmium

30.2

8.4

5.8

9.3

8.1

8.1

8.4

4.9

4.0

5.9

6.3

2.4

4.5

4.7

5.0

Chromium

18.9

19.5

31.5

25.8

31.8

29.2

25.6

36.7

33.3

28.0

35.3

20.5

29.3

30.5

23.7

Copper

3,700

286

881

1,110

1,350

1,240

1,020

880

475

53

414

9

214

543

166

Iron

29,800

22,100

16,800

23,600

28,500

23,100

25,300

25,300

20,000

20,600

20,300

14,800

16,300

20,900

18,600

Lead

381

68

67

113

167

143

139

122

67

126

78

12

47

78

36

Manganese

2,770

10,600

11,000

5,960

5,890

2,100

2,560

2,410

1,390

4,230

1,650

170

866

822

1,150

Nickel

14.1

14.6

17.7

16.6

15.2

10.5

10.6

12.9

10.9

10.4

12.8

9.5

9.4

13.3

11.0

Silver

8.3

3.5

5.1

4.9

6.6

5.3

4.8

4.1

2.3

5.8

3.0

.7

1.7

2.8

1.5

Zinc

5,620

1,000

373

1,170

1,120

1,130

1,070

961

670

503

863

32

586

1,090

363

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

TABLE 14 51
Table 15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, August 2002

[Bulk 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: |ig/g, micrograms per gram of dry sample weight]

Station number _ . 

, , . Station name (fig- 1)

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340500

12353000

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Warm Springs Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek diversion, 

near Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, near Bonner

Clark Fork above Missoula

Clark Fork below Missoula 1

Number 

of composite 

samples

2

1

2

2

2

2

2

2

2

2

2

2

2

2

2

Concentration

Cadmium

30.2

.9

1.5

6.0

2.3

5.9

6.9

7.0

3.5

3.4

3.1

3.2

2.9

5.2

3.0

Chromium

18.1

5.2

7.4

20.0

6.8

19.7

17.6

29.2

21.9

13.3

12.7

17.5

21.8

31.5

12.7

Copper

3,800

10

130

730

240

760

610

710

270

20

130

160

10

630

80

Iron

28,700

6,100

8,000

19,000

12,300

20,400

24,400

23,000

18,000

13,500

14,400

13,300

14,200

21,500

13,300

Lead

398

6

24

89

49

101

97

102

46

84

31

38

12

84

23

.» in Hg/g

Manganese

2,660

1,020

4,240

4,540

1,290

1,350

1,630

1,390

380

2,770

410

700

140

890

560

Nickel

12.7

4.9

6.9

11.2

4.5

9.0

9.0

11.6

10.2

6.2

7.7

8.4

9.8

14.4

8.1

Silver

8.1

.4

1.3

3.3

1.1

3.3

2.8

3.1

1.3

4.6

.9

1.3

.5

3.4

.7

Zinc

5,930

100

160

760

340

730

740

860

460

270

380

420

40

1,210

180

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

52 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

[Abbreviations: M-g/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

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

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

(^g/g)

SRM sample 2709

0.4

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)

--

80.9

71.3

89.3

90.2

80.6

88.4

--

82.5

104.7

36.3

74.6

88.3

103.7

78.6

89.2

83.5

89.2

95-percent confidence 

interval for SRM 

recovery 

(percent)

--

79.8-82.0

70.8-71.9

89.0-89.6

88.3-92.1

76.2-85.0

87.4-88.4

--

81.4-83.5

104-106

32.2-40.4

72.7-76.5

87.5-89.1

102-105

76.7-80.5

87.5-90.9

81.2-85.8

88.0-90.3

TABLE 16 53
Table 17. Trace-element analyses of procedural blanks for bed sediment

[Abbreviation: |j,g/mL, micrograms per milliliter. Dilution ratio is the proportion of initial volume of concentrated nitric acid used as a digesting reagent to final 

of 0.6 N (normal) hydrochloric acid used for reconstituting dried residue. Symbol: <, less than]

Trace-element concentration, in |j,

II

3 1

Station number

12323600

12323770

12323800

461903112440701

12324200

12324680

12331500

12334510

12334550

12340500

12353000

12353000

c,. .. Dilution 

Station name 

ratio

Silver Bow Creek at Opportunity 1 : 1

Warm Springs Creek at Warm Springs 1: 1

Clark Fork near Galen 1 : 1

Clark Fork at Dempsey Creek diversion, near Racetrack 1 : 1

Clark Fork at Deer Lodge 1 : 1

Clark Fork at Goldcreek 1 : 1

Flint Creek near Drummond 1 : 1

Rock Creek near Clinton 1 : 1

Clark Fork at Turah Bridge, near Bonner 1 : 1

Clark Fork above Missoula 1 : 1

Clark Fork below Missoula 1 : 1

Clark Fork below Missoula 1 : 1

Cadmium

<0.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

Chromium

<0.09

<.09

.10

<.09

<.09

<.09

<.09

<.09

<.09

<.09

<.09

<.09

Copper

<0.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

Iron

<0.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

.05

<.04

<.04

Lead

<0.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

Manganese

<0.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001
Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 2002

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

Taxon

Brachycentrus spp.

Hydropsyche cockerelli

Hydropsyche spp.

Hydropsyche cockerelli

Hydropsyche occidentalis 

Arctopsyche grandis

Hydropsyche spp.

Hydropsyche cockerelli

Hydropsyche occidentalis 

Hydropsyche cockerelli

Hydropsyche cockerelli 

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Arctopsyche grandis

Hydropsyche cockerelli

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Number of Concentration,

composite Cad- Chro- Cop- Jron 

samples mium mium per

12323600 Silver Bow Creek at Opportunity

1 12.2 <0.6 674 1,190

1 9.7 1.8 1,090 2,660

2 8.6 .7 881 2,110

12323750 Silver Bow Creek at Warm Springs

2 .7 .4 30.2 998

2 1.6 1.1 45.7 2,810 

12323770 Warm Sprines Creek at Warm Sprines

1 3.0 .8 78.3 757

1 1.1 1.4 95.9 1,220

12323800 Clark Fork near Galen

3 1.5 1.3 88.9 1,340

1 1.6 .4 83.3 1,450 

461415112450801 Clark Fork below Lost Creek, near Galen

2 1.9 .8 89.7 1,730

461559112443301 Clark Fork near Racetrack

injag/g

Lead

21.5

47.2

40.2

2.3

7.9 

3.0

5.2

7.3

8.6 

11.1

1 1.5 .6 74.1 731 4.8 

461903112440701 Clark Fork at Dempsev Creek diversion, near Racetrack

2 1.3 .5 65.3 601

1 1.5 .8 79.8 995

12324200 Clark Fork at Deer Lodge

1 1.7 .5 109 738

1 1.3 1.2 101 1,190

12324680 Clark Fork at Goldcreek

4 1.7 .5 22.1 432

2 .6 .3 53.4 307

2 1.1 .7 34.0 870

12331500 Flint Creek near Drummond

1 .4 .9 15.5 1,050

1 .9 1.3 12.4 3,720

12331800 Clark Fork near Drummond

3 1.2 .3 18.3 306

2 .6 .2 58.1 132

3 .7 .6 32.2 818

7.4

9.5

7.9

10.1

2.1

1.2

4.4

6.5

22.4

2.9

.6

6.1

Manganese

817

1,160

920

1,540

3,350 

3,560

3,390

2,650

2,800 

1,920

1,570 

754

1,510

693

1,490

875

203

1,250

1,590

2,690

566

124

992

Nickel

2.1

3.6

2.4

1.2

2.6

2.2

1.8

1.4

1.8 

1.1

.8

.5

1.3

.7

1.2

.5

.6

.9

1.2

2.7

.4

.2

.8

Zinc

995

1,380

1,090

168

207 

183

125

171

170

247

167 

178

231

194

256

181

316

181

192

196

173

278

170

TABLE 18 55
Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 2002 (Continued)

Taxon

Number o 

composite 

samples

f

Cad- Chromium mium

Concentration, in |4g/g

CopIron 

per

Lead

Manganese

Nickel Zinc

123345JO Rock Creek near Clinton

Arctopsyche grandis

Claassenia sabulosa 

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

2 .4 1.1 7.8 1,080 .5

1 .2 .2 23.9 102 <5 

12334550 Clark Fork at Tlirah Bridge, near Bonner

2

1

2

1

.7 .7

.3 .5

.6 1.2

.7 1.2

22.6 570

78.7 112

37.1 1,090

35.2 1,160

2.3

.3

3.9

4.9

307

32 

511

91

506

728

1.6

.4 

.8

.2

1.2

1.2

141

180

172

244

171

200

12340500 Clark Fork above Missoula

Arctopsyche grandis

Claassenia sabulosa

3

2

.5 .7

.3 .4

23.1 731

50.1 306

4.4

1.4

758

177

.7

.4

225

280

12353000 Clark Fork below Missoula1

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

2

3

4

.8 1.4

.4 .3

.9 2.1

28.8 1,480

49.9 143

52.8 2,160

3.7

.4

5.7

556

91

640

1.2

.2

1.8

169

234

181

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

56 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

[Abbreviations: |j.g/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

Ul

12

12

12

Certified concentration

(l^g/g)

SRM sample TORT-2

26.7

.77

106

105

.35

13.6

2.5

180

Mean SRM recovery 

(percent)

87.7

116

94.3

96.1

62.2

91.4

84.6

87.9

95-percent confidence 

interval for SRM 

recovery 

(percent)

85.9-89.5

83.7-148

93.2-95.4

90.8-101

55.6-68.8

89.6-93.2

79.7-89.5

86.8-89.0

'Lead concentration in one sample was below the analytical detection limit.

TABLE 19 57
Table 20. Trace-element analyses of procedural blanks for biota

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

Trace-element concentration, in |4g/mL

number

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340500

12353000

LJl'CftllUll

name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Warm Springs Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek diversion, 

near Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, near Bonner

Clark Fork above Missoula

Clark Fork below Missoula

1S11UUU11 

ratio Cad- Chro- T _ . Copper Iron Lead mium mmm

1:1 <0.01 <0.01 <0.06 <0.10 <0.01

1:1 <.01 <01 <.06 <.10 <01

1:1 <.01 <.01 <.06 <.10 <.01

1:1 <.01 <01 <.06 <.10 <.01

1:1 <.01 <.01 <.06 <.10 <.01

1:1 <.01 <.01 <.06 <.10 <.01

1:1 <.01 <.01 <.06 <.10 <.01

1:1 <.01 <.01 <.06 <.10 <.01

1:1 <01 <.01 <.06 <10 <.01

1:1 <01 <.01 <.06 <.10 <.01

1:1 <.01 <.01 <.06 <.10 <.01

1:1 <.01 <.01 <.06 <.10 <.01

1:1 <.01 <.01 <.06 <.10 <.01

1:1 <.01 <01 <.06 <.10 <.01

1:1 <.01 <.01 <06 <.10 <.01

Manga- ... , , . fe Nickel Zinc 

nese

<0.01 <0.06 <0.01

<.01 <.06 <.01

<.01 <.06 <.01

<.01 <.06 <.01

<01 <.06 <.01

<.01 <.06 <.01

<.01 <.06 <.01

<.01 <.06 <.01

<.01 <.06 <.01

<.01 <.06 <.01

<.01 <.06 <.01

<.01 <.06 <.01

<.01 <06 <.01

<.01 <.06 <01

<.01 <.06 <.01

58 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2002

[Abbreviations: ft3/s, cubic feet per second; °C, degrees Celsius; E, estimated; |0,g/L, micrograms per liter; |o,S/cm, microsiemens per centimeter at 

25 °C; mg/L, milligrams per liter; mm, millimeter; ton/d, tons per day. Symbols: <, less than laboratory reporting level 1 ; --, 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 (|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 (ng/L)

Cadmium, total recoverable (|Xg/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (|ig/L)

Copper, dissolved (M-g/L)

Iron, total recoverable (|ig/L)

Iron, dissolved (|ig/L)

Lead, total recoverable (|ig/L)

Lead, dissolved (Hg/L)

Manganese, total recoverable (|ig/L)

Manganese, dissolved (|ig/L)

Zinc, total recoverable (ng/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,

75

75

75

75

75

75

75

75

75

75

75

75

75

75

75

75

75

75

75

75

75

75

75

75

156

412

17.5

8.2

150

41.8

11.0

18

13

.06

.5

52

10

4,220

478

47

1

240

144

130

11

139

58.5

97

Mean

MONT.

Median

December 1996-September 2002

1.9

116

2.0

7.3

38

10.6

2.71

<2

1

<.04

<.l

1.5

<E.8

140

15

<1

<.08

24

17

<10

<3

2

.02

50

15

265

8.2

7.8

105

30

7.3

25

4

--

2<.l

7

24

713

161

22

2.1

62

43

2 11

24

15

1.5

82

8.2

271

7.5

7.8

110

31

7.4

4

3

<1

<.l

6

3

560

150

1

<.5

53

39

3

2

8

.16

84

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

through September 2002 (Continued)

Property or constituent and reporting unit

12323250--SILVER BOW CREEK

Number of 

samples

BELOW BI

Maximum Minimum Mean Median

ACKTAIL CREEK. AT BUTTE. MONT.

Period of record for water-quality data: March 1993-August 1995, December 1996-September 2002

Streamflow, instantaneous (ft3/s) 75 134 13 30

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 (jig/L)

Arsenic, dissolved (|ig/L)

Cadmium, total recoverable (|lg/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (jig/L)

Copper, dissolved (jig/L)

Iron, total recoverable (u,g/L) 

Iron, dissolved (|ig/L)

Lead, total recoverable (|ig/L) 

Lead, dissolved (|ig/L)

Manganese, total recoverable (u,g/L)

Manganese, dissolved (u,g/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

75

75

75

75

75

75

75

75

75

75

75

75 

75

75 

75

75

75

75

75

74

74

74

691

20.0

8.1

180

51.6

13.0

45

13

6

6.2

550

303

7,400 

270

250

2.4

1,600

1,700

2,200

2,200

405

70.2

98

226

1.0

7.2

66

19.0

4.51

4

4

.18

E.I

13.5

4.5

90 

E10

<1

<.5

29

21.4

86

60

3

.14

42

469

10.2

7.6

148

42

10

14

7

2.2

1.6

125

54

1,160 

2 86

20 

2 .6

552

497

655

541

31

3.8

83

24

478

9.0

7.6

150

43

11

11

7

2

1.3

91

39

700

74

8 

<1

510

471

530

424

13

.98

86

60 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2002 (Continued)

Number of 

Property or constituent and reporting unit 

samples

Maximum Minimum Mean Median

12323600--SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (jiS/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 (Hg/L)

Cadmium, total recoverable (|ig/L)

Cadmium, dissolved (u,g/L)

Copper, total recoverable (|ig/L)

Copper, dissolved (Hg/L)

Iron, total recoverable (|ig/L)

Iron, dissolved (|ig/L)

Lead, total recoverable (|ig/L)

Lead, dissolved (u,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)

March 1993-August 1995, December 1996-September 2002

78

77

77

77

77

77

77

77

77

77

77

77

77

77

77

77

77

77

77

77

77

78

78

78

361

616

22.5

9.5

220

62.7

15.0

235

34

49

41

3,900

450

24,100

307

650

5.1

10,000

9,300

15,000

13,000

801

781

95

13

202

0.0

7.2

60

18.5

3.42

11

1

.61

.1

59.6

19.4

260

<3

7

<.5

174

68

143

27

6

.25

37

77

399

9.1

8.4

142

42

9.1

30

10

22.7

1.6

265

56

1,780

247

46

2.8

698

568

705

421

59

26

77

54

388

9.0

8.3

140

41 

8.7

18

9

1.9

1.0

140

44

860

25

17

<1

508

440

470

250

18

2.8

80

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

through September 2002 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

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

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

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

Arsenic, dissolved (|lg/L)

Cadmium, total recoverable (|ig/L)

Cadmium, dissolved (|Ug/L)

Copper, total recoverable (jig/L)

Copper, dissolved (Hg/L)

Iron, total recoverable (jig/L)

Iron, dissolved (|ig/L)

Lead, total recoverable (jig/L)

Lead, dissolved (Hg/L)

Manganese, total recoverable (jxg/L)

Manganese, dissolved (jig/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)

84

82

83

82

82

82

82

82

82

82

82

82

82

82

82

82

82

82

82

82

82

84

84

83

March 1993-September 2002

662

783

22.0

9.3

310

90.4

21.4

94

60

.5

.3

80

40

3,000

93

15

1.0

899

875

180

73

229

279

97

16

249

.5

8.0

97

27.9

5.94

10

6.8

<.l

<.l

3.4

1.9

70

<5

<1

<.5

55

11.8

<10

<3

1

.11

43

148

464

11.0

8.8

191

56

13

26

21

2<.l

2-l

20

10

370

2 17

22

2.1

197

128

243

2 11

13

8.9

82

94

466

11.0

8.8

190

56

13

24

21

<1

<.l

14

8

300

14

2

<.5

160

94

30

6

7

1.8

85

62 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2002 (Continued)

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

12323770-WARM SPRINGS CREEK AT WARM SPRINGS. MONT. 

Period of record for water quality data: March 1993-September 2002

Streamflow, instantaneous (ft3/s) 58 420 2.8 99 57

Specific conductance, onsite ((iS/cm) 57 795 139 301 269

Temperature, water (°C) 58 18 .5 9.1 9.0

pH, onsite (standard units) 57 8.7 7.4 8.3 8.3

Hardness, total (mg/L as CaCO3 ) 57 420 40 145 130

Calcium, dissolved (mg/L) 57 130 10.5 44 40

Magnesium, dissolved (mg/L) 57 22.0 3.29 8.4 7.4

Arsenic, total recoverable (|ig/L) 57 27 3 8 6

Arsenic, dissolved (|0,g/L) 57 14 2 5 4

Cadmium, total recoverable (|ig/L) 57 .2 <.l 2.07 <1

Cadmium, dissolved (|ig/L) 57 E.I <.l 2 .04 <.l

Copper, total recoverable (u.g/L) 57 96.7 2.3 20 10

Copper, dissolved (|xg/L) 57 16 1 4 3

Iron, total recoverable (|ig/L) 57 1,660 40 314 130

Iron, dissolved (|ig/L) 57 30 <5 2 10 9

Lead, total recoverable (|ig/L) 57 14 <1 22 <1

Lead, dissolved (jig/L) 57 1.8 <.08 -- <.5

Manganese, total recoverable (|ig/L) 57 1,400 57 231 200

Manganese, dissolved (ng/L) 57 570 22.6 140 110

Zinc, total recoverable Qig/L) 57 60 <10 2 11 3

Zinc, dissolved (|ig/L) 57 10 <1 22 <20

Sediment, suspended concentration (mg/L) 58 100 2 19 10

Sediment, suspended discharge (ton/d) 57 87.3 .05 10 1.2

Sediment, suspended (percent finer than 0.062 mm) 58 88 55 74 75

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

through September 2002 (Continued)

Property or constituent and reporting unit Maximum Minimum Mean Median

12323800-CLARK FORK NEAR GALEN. MONT. 

Period of record for water-quality data: July 1988-September 2002

Streamflow, instantaneous (ft3/s) 125 1,050 14 211 126

Specific conductance, onsite (|iS/cm) 113 720 197 430 442

Temperature, water (°C) 124 22.5 0.0 9.8 9.8

pH, onsite (standard units) 112 9.0 7.5 8.5 8.5

Hardness, total (mg/L as CaCO3 ) 111 370 81 187 190

Calcium, dissolved (mg/L) 111 110 24.2 55 57

Magnesium, dissolved (mg/L) 111 22.0 5.08 12 12

Arsenic, total recoverable (|lg/L) 111 78 3 20 16

Arsenic, dissolved (|ig/L) 111 53 4 15 12

Cadmium, total recoverable (ng/L) 111 3 <.l 2.2 <1

Cadmium, dissolved (|ig/L) 111 1 <.l 2 .07 <.l

Copper, total recoverable (ng/L) 110 240 4.8 32 19

Copper, dissolved (|lg/L) 111 50 2.3 10 8

Iron, total recoverable (|ig/L) 111 9,200 60 548 290

Iron, dissolved (|ig/L) 111 110 <3 2 16 10

Lead, total recoverable (|ig/L) 111 28 <1 24 2

Lead, dissolved (|ig/L) 111 3 <.5 2 .2 <.6

Manganese, total recoverable (|ig/L)

Manganese, dissolved (jig/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)

111

111

111

111

125

125

124

1,400

460

360

110

338

459

97

47

25.2

<10

<3

2

.12

41

257

118

249

2 13

20

23

78

200

89

30

7

8

2.3

78

64 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2002 (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

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 (p.g/L)

Arsenic, dissolved (|ig/L)

Cadmium, total recoverable (|ig/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (|4.g/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)

177

160

176

125

117

117

117

127

127

127

127

126

127

127

127

127

127

127

127

127

127

177

177

168

: March 1985-September 2002

1,920

642

23.0

8.9

270

81.0

18

215

39

5

2

1,500

120

29,000

190

200

6

4,600

400

1,700

230

2,250

8,690

99

23

234

0.0

7.4

95

28.2

5.9

8

6

<.l

<.l

8.2

3.2

30

<3

<1

<.08

12

1

4

<10

2

.29

40

293

488

9.7

8.3

205

60

13

25

14

2.5

2 .08

95

12

1,820

2 15

2 12

2 .4

282

44

107

2 14

80

179

71

219

508

10.0

8.3

220

63

14

17

13

<1

<.l

41

9

660

9

5

<1

160

33

53

10

23

12

72

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

through September 2002 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (fiS/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 (|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)

102

90

101

89

84

84

84

89

89

89

89

88

89

89

89

89

88

89

89

89

89

102

102

102

March 1985-September 2002

2,080

338

22

8.6

160

46.9

10.2

17

7

2

.2

45

7

25,000

120

25

6

1,100

45.2

140

24

1,410

7,920

97

15

120

0.0

7.0

51

14.0

3.30

4

3

<.l

<.04

<1

<1

20

<3

<1

<5

<10

1.0

<1

<1

1

.08

32

288

228

8.4

8.1

104

30

7.0

7

5

2 .1

-

24

22

1,110

235

23

2 .4

268

9

2 12

23

50

136

75

184

221

9.0

8.1

100

30

7.0

6

5

<1

<.l

2

2

260

26

<5

<1

30

8

<40

<20

10

5.2

79

66 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2002 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12324680--CLARK FORK AT GOLDCREEK MONT.

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 (|J.g/L)

Arsenic, dissolved (jig/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 (|4.g/L)

Lead, total recoverable (|ig/L)

Lead, dissolved (|ig/L)

Manganese, total recoverable (|ig/L)

Manganese, dissolved (|ig/L)

Zinc, total recoverable (jig/L)

Zinc, dissolved (|ig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

83

82

83

82

82

82

82

82

82

82

82

81

81

82

82

81

81

82

82

82

82

83

83

83

: March 1993-September 2002

3,920

510

21.5

8.8

230

68.0

15.0

75

20

2

.2

440

36

12,000

100

73

.8

1,100

57.3

510

26

752

7,960

93

87

207

0.0

7.9

86

25.9

5.15

7

5.8

<.l

<.l

5.2

2.1

30

<3

<1

<.08

10

4.0

2

<1

2

.94

43

757

373

9.6

8.4

163

48

10

16

10

2 .2

2.04

46

7

990

2 19

26

2.1

138

20

54

27

58

266

75

513

392

9.5

8.3

170

51

11

13

10

<1

<.l

29

6

510

12

4

<.5

100

19

35

4

23

36

78

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

through September 2002 (Continued)

Property or constituent and reporting unit

12331500--FL

Number of 

samples

INT CREEK NEAR

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)

131

120

129

117

110

110

110

117

117

117

117

116

117

117

117

117

117

117

117

117

117

131

131

131

Maximum Minimum Mean Median

DRUMMOND. MONT.

March 1985-September 2002

892

529

21.0

8.8

260

73.0

20

57

20

3

.1

32

7

7,200

240

87

7

1,600

139

290

27

556

904

98

2.8

134

0.0

7.5

59

16.4

4.3

7

5

<.04

<.04

1

<1

60

<3

<1

<.5

50

14

<10

<1

3

.02

28

182

304

9.0

8.3

142

39

11

17

9

2.2

-

7

22

886

239

2 11

2 .7

209

42

238

25

51

44

80

119

302

9.5

8.3

140

38

11

13

9

<1

<.l

4

2

470

21

7

<1

132

37

20

3

26

8.0

84

68 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2002 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean

1,060 

408 

10.5 

8.3 

183 

52 

13 

17 

11

2 .2 

2<.l 

47 

7

1,120 

220 

29 

2.2

Median

12331800-CLARK FORK NEAR DRUMMQND. MONT. 

Period of record for water-quality data: March 1993-September 2002

Streamflow, instantaneous (ft3/s) 83 3,860 149

Specific conductance, onsite (|iS/cm) 82 630 189

Temperature, water (°C) 83 22.5 .5

pH, onsite (standard units) 82 8.5 7.8

Hardness, total (mg/L as CaCO3 ) 82 300 74

Calcium, dissolved (mg/L) 82 83 21

Magnesium, dissolved (mg/L) 82 22 5.2

Arsenic, total recoverable (p.g/L) 82 62 8

Arsenic, dissolved (\igfL) 82 20 6.6

Cadmium, total recoverable (|ig/L) 82 2 <.l

Cadmium, dissolved (Hg/L) 82 .2 <. 1

Copper, total recoverable (|ig/L) 80 360 4.6

Copper, dissolved ([ig/L) 80 21 1

Iron, total recoverable ([ig/L) 82 8,800 20

Iron, dissolved ([ig/L) 82 150 <3

Lead, total recoverable (|ig/L) 78 56 <1

Lead, dissolved ([ig/L) 78 1.2 <.08

768

426

11.0

8.3

190

55

13

13

10

24

5

540

9

4

Manganese, total recoverable (|ig/L)

Manganese, dissolved (jig/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)

82

82

82

82

83

83

83

880

60.7

490

21

530

4,720

92

8

4.5

3

<3

2

1.7

38

161

17

71

27

71

363

74

105

15

40

5

29

64

75

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

through September 2002 (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 (fiS/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 (fig/L)

Cadmium, dissolved (|ig/L)

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

Copper, dissolved (fig/L)

Iron, total recoverable (|ig/L)

Iron, dissolved ((ig/L)

Lead, total recoverable (jig/L)

Lead, dissolved (|0.g/L)

Manganese, total recoverable (|ig/L)

Manganese, dissolved (|ig/L)

Zinc, total recoverable (|ig/L)

Zinc, dissolved (jig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

101

92

101

91

83

83

83

89

89

89

89

87

88

89

89

87

87

89

89

89

89

101

101

101

Minimum

MONT.

Mean Median

: March 1985-September 2002

5,060

158

18

8.8

90

23.0

8.00

5

1

3

1

41

6

2,100

163

19

5

90

8

60

15

223

3,050

95

113

53

0.0

6.9

22

5.92

1.86

<1

<1

<.04

<.04

<.6

<1

20

<5

<1

<.08

<10

<1

<1

<1

1

.31

35

985

106

8.2

8.0

49

13

4.2

2 .9

2.6

2 .2

--

24

2 1

304

235

22

2.5

2 16

22

26

22

21

145

69

558

99

8.5

8.0

49

13

4.0

<1

<1

<1

<.l

2

<1

140

29

<1

<1

8

2

<10

<3

6

12

71

70 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2002 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

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

Period of record for water-quality data: March 1985-September 2002

Streamflow, instantaneous (ft3/s) 180 9,560 296 1,860 1,120

Specific conductance, onsite (jiS/cm) 155 483 140 306 323

Temperature, water (°C) 179 22.0 0.0 9.2 9.5

pH, onsite (standard units) 126 8.8 7.4 8.2 8.3

Hardness, total (mg/L as CaCO3 ) 116 210 58 133 135

Calcium, dissolved (mg/L) 116 59.0 16.4 37 38

Magnesium, dissolved (mg/L) 116 14.0 3.94 9.5 9.5

Arsenic, total recoverable (|0,g/L) 125 110 3 11 7

Arsenic, dissolved (jig/L) 125 17 2.7 6 5

Cadmium, total recoverable (|ig/L) 125 4 <.l 2 .3 <1

Cadmium, dissolved (jig/L) 125 .11 <.l - <.l

Copper, total recoverable ([ig/L) 123 500 3 41 19

Copper, dissolved ([ig/L) 124 25 El.l 5 4

Iron, total recoverable ([ig/L) 125 19,000 50 1,220 450

Iron, dissolved ([ig/L) 125 190 <3 225 14

Lead, total recoverable ([ig/L) 121 100 <1 29 4

Lead, dissolved Qig/L) 121 7 <.08 2 .4 <1

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)

125

125

125

124

180

180

169

2,000

37.4

1,100

39

1,370

34,700

98

10

1.0

<10

<3

2

3.5

27

145

8

273

27

63

697

73

80

7

36

5

20

62

74

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

through September 2002 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

132

109

132

92

85

85

85

92

92

92

92

89

90

92

92

88

88

92

92

92

92

132

132

130

13,400

294

21.0

8.7

140

37

13

4

2

2

I 

34

7

3,600

100

25

8

180

II 

60 

15 

271 

7,670 

98

344

131 

0.0 

7.5

55

14 

4.9

<1

<1 

<.04 

<.04

<1

<1

20

<3

<1 

<.08

1 

1.1

42

2,750

206

9.1

8.3

101

26

8.9

2 1

2.9

2 .2

514

2 19

23

2

234

23

27

23

32

583

80

.5

Median

12340000-BLACKFOOT RIVER NEAR BONNER. MONT. 

Period of record for water-quality data: March 1985-September 2002

Streamflow, instantaneous (ft /s) 

Specific conductance, onsite (jiS/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 (|4.g/L) 

Cadmium, dissolved (fig/L) 

Copper, total recoverable (|ig/L) 

Copper, dissolved (jig/L) 

Iron, total recoverable ((ig/L) 

Iron, dissolved (|J.g/L) 

Lead, total recoverable (|ig/L) 

Lead, dissolved (|ig/L) 

Manganese, total recoverable (|ig/L) 

Manganese, dissolved (M-g/L) 

Zinc, total recoverable (|ig/L) 

Zinc, dissolved (|ig/L)

1,320

205

9.2

8.3

97

25

8.5

1

.9

3

1

235

12

20 

2

dO 

<3 

10 

32 

82

72 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) 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 2002 (Continued)

Property or constituent and reporting unit

12340500--CI

Number of ._ . Maximum samples

ARK FORK ABOVE MISSOULA

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 (jig/L)

Arsenic, dissolved (|ig/L)

Cadmium, total recoverable (|ig/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (p.g/L)

Copper, dissolved (|ig/L)

Iron, total recoverable ([J-g/L)

Iron, dissolved (Jig/L)

Lead, total recoverable (jig/L)

Lead, dissolved (Hg/L)

Manganese, total recoverable (|ig/L)

Manganese, dissolved (jig/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)

146

123

143

103

103

103

103

103

103

103

103

101

102

103

103

98

98

103

103

103

103

146

146

141

Minimum

. MONT.

Mean Median

July 1986-September 2002

21,600

399

20.0

8.7

170

46

13.0

69

9

5

.2

400

11

13,000

200

78

1.2

1,100

230

1,100

16

824

21,900

99

720

142

0.0

7.9

61

14

5.28

1

1

<.l

<.04

2

.7

40

<3

<1

<.08

10

6.2

<10

<1

2

5.8

44

4,430

255

9.1

8.3

117

32

9.3

5

3

2.1

-

16

3

621

222

23

2 .2

65

18

232

24

38

984

87

2,360

262

8.5

8.3

120

32

9.3

4

3

<1

<.l

8

2

230

15

2

<.6

40

14

13

2

11

69

91

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

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

TABLE 21 73
Table 22. Statistical summary of fine-grained bed-sediment data for the upper Clark Fork basin, Montana, 

August 1986 through August 2002

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

weight. Symbol: <, less than minimum reporting level. 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

Minimum Mean

mum

Median

12323600--SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for fine-grained bed-sediment data: 1992-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

11

10

11

11

11

11

10

11

11

42.0 23.7 32.3

32.4 16.8 25.7

9,020 3,700 5,240

41,200 28,200 36,600

1,030 381 778

9,220 1,690 3,260

21.4 12.7 15.7

20.0 8.3 15.9

13,400 5,620 8,530

30.1

26.2

4,810

37,500

833

2,590

15.8

16.4

8,010

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.

Period of record for fine-grained bed-sediment data: 1992-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

11

10

11

11

11

11

10

11

11

12.2 4.2 7.5

34.1 12.3 20.8

769 169 382

27,200 15,400 21,100

100 49 72

17,700 1,470 7,300

19.1 9.2 14.8

3.5 .3 4.6

2,220 620 1,090

6.7

21.2

286

20,800

68

7,230

15.0

'1.6

840

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

Period of record for fine-grained bed-sediment data: 1995, 1997, 1999, 2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

4

4

4

4

4

4

4

4

4

5.8 1.3 3.4

33.4 27.5 30.8

892 779 850

22,400 16,800 20,400

86 67 81

11,000 2,020 6,950

21.9 17.6 19.2

5.1 3.1 3.8

421 372 391

3.2

31.1

864

21,200

85

7,410

18.6

3.5

385

12323800-CLARK FORK NEAR GALEN. MONT.

Period of record for fine-grained bed-sediment data: 1987, 1991-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

13

10

13

13

13

13

10

13

13

20.1 4.0 10.0

33.9 19.1 27.0

2,300 991 1,300

39,800 22,600 28,400

235 113 146

15,600 2,780 8,550

23.2 15.4 18.8

7.3 <3.2 U.3

3,560 1,090 1,740

9.3

26.7

1,220

27,700

136

8,470

18.6

'4.2

1,370

74 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 1986 through August 2002 (Continued)

 ... , Number of Constituent samplesMaximum

Minimum Mean Median

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

Period of record for fine-grained bed-sediment data: 1996-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

7

7

7

7

7

7

7

7

7

10.5

34.5

2,050

32,800

200

5,900

19.9

7.8

1,680

6.5 8.1

22.3 29.5

1,350 1,570

26,300 30,600

167 183

3,540 4,960

13.4 17.2

4.2 6.4

1,120 1,400

8.1

31.8

1,440

31,400

182

5,000

17.8

6.6

1,450

4615591 12443301--CL ARK FORK NEAR RACETRACK. MONT.

Period of record for fine-grained bed-sediment data: 1996-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

7

7

7

7

7

7

7

7

7

8.6

33.3

1,610

31,700

186

4,120

18.4

6.1

1,550

5.0 7.1

19.1 26.7

933 1,230

23,100 27,200

128 147

2,100 3,050

10.5 14.6

<3.3 1 4.9

1,030 1,230

7.5

29.2

1,240

28,600

143

2,920

16.5

'5.3

1,170

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

Period of record for fine-grained bed-sediment data: 1996-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

7

7

7

7

7

7

7

7

7

10.3

34.1

1,550

33,700

152

6,410

16.9

6.2

1,570

4.3 7.0

16.0 26.3

766 1,060

22,000 27,400

115 132

1,810 3,230

9.5 13.6

2.7 4.8

900 1,160

6.9

26.4

1,030

28,200

130

2,630

15.1

4.8

1,070

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1990-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

15

10

15

15

15

15

10

15

15

10.0

43.9

4,180

35,300

242

6,020

21.1

7.9

1,730

4.4 6.7

19.5 32.0

837 1,400

22,600 28,100

121 155

1,460 2,770

12.2 16.3

2.4 4.7

940 1,290

6.3

33.9

1,070

28,400

150

2,410

16.1

4.5

1,320

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

August 1986 through August 2002 (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

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

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

5 2.3 .2 1.1

3 54.4 22.1 43.1

5 85 38 56

5 30,700 16,100 24,200

5 53 36 40

5 2,700 905 1,420

3 21.9 13.6 17.7

5 .9 <.5 1 .6

5 204 161 176

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for fine-grained bed-sediment data: 1992-2002

11 8.1 3.5 5.3

10 48.9 24.9 33.7

11 1,080 393 753

11 30,600 19,900 24,700

11 152 61 104

11 2,610 1,160 1,810

10 18.6 10.9 15.5

11 4.8 2.3 3.4

11 1,320 590 1,050

12331500--FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for fine-grained bed-sediment data: 1986, 1989, 1992-2002

13 7.0 <2 *3.3

10 29.2 20.4 25.0

13 73 53 61

13 28,100 19,800 23,400

13 240 126 172

13 5,510 2,370 3,790

10 14.9 10.4 12.5

12 7.8 5.0 6.4

13 777 503 636

12331800--CLARK FORK NEAR DRUMMOND. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1991-2002

14 7.7 2.6 4.9

10 35.4 17.0 30.1

14 747 387 525

14 27,000 16,500 22,100

14 135 72 96

14 2,790 1,150 1,770

10 16.8 11.6 14.5

14 4.7 <3.2 ^.0

14 1,230 785 1,040

Median

.9

52.9

40

24,200

37

1,040

17.6

*.8

170

5.5

32.6

766

24,400

107

1,770

16.2

3.2

1,110

'3.1

25.2

63

23,400

168

3,910

12.1

6.5

648

4.8

32.1

524

23,200

95

1,700

15.4

! 2.9

1,030

76 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 1986 through August 2002 (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, 2001-02

14 3.7 <.2 ^8

9 27.9 16.5 22.2

14 16 3 12 

14 21,400 13,100 17,600 

14 16 <3 1 9

14 724 126 374 

9 14.8 9.5 12.1

13 1.9 <.3 ! .5

14 58 32 46 

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

Period of record for fine-grained bed-sediment data: 1986, 1991-2002

13 7.3 3.1 4.2

10 34.7 15.3 26.0

13 635 214 388 

13 24,400 15,100 19,400 

13 115 47 75

13 2,270 671 1,180 

10 19.1 9.3 13.8 

13 3.9 <1.9 1 22

13 1,160 586 890

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 1 .6

8 25.8 15.1 20.5

11 27 16 21 

11 20,200 12,400 17,000 

11 20 <13 43

11 683 298 524 

8 14.3 9.4 12.2 

11 1.0 <.3 U

11 73 35 60 

12340500--CLARK FORK ABOVE MISSOULA. MONT.

Period of record for fine-grained bed-sediment data: 1997-2002

6 4.7 1.5 3.2

6 30.6 19.0 26.6

6 543 166 327 

6 24,300 18,100 20,800 

6 78 37 55

6 1,370 480 980 

6 15.8 11.8 13.7 

6 2.9 .8 1 2.0

6 1,090 438 700

Median

j

21.3

13 

17,800 

'9

330 

12.7

l<.3

48 

3.9

28.4

352 

17,500 

70

1,080 

14.0 

'2.1

880

21.8

21 

17,800 

43

535 

12.6

61 

3.1

29.3

258 

20,600 

53

990 

13.9

1 22

622

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

August 1986 through August 2002 (Continued)

 ... . Number of Constituent samples

Maximum

Minimum Mean Median

12353000-CLARK FORK BELOW MISSOULA. MONT.2

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel 

Silver

Zinc

Period of record for fine-grained bed-sediment data: 1986, 1990-2002

14 6.0 1.1 2.3

10

14 

14

14

14 

10 

14

14

27.6

293 

21,100

58

2,530 

14.1 

3.0

675

12.3

87 

13,400

12

446 

8.9 

.4

252

21.9

153 

18,400

37

1,320 

12.4 

'1.3

402

1.9

22.6

140 

19,000

36

1,210 

12.7 

4.3

395

1 Value determined by arbitrarily substituting one-half of the detection level for censored (<) values, when both uncensored and censored values are used in determining the mean and/or median. When all data are below the detection level, the median is determined by ranking the censored values in order of detection level. No mean is reported when all values are below the detection 

level.

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

78 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 1993 through August 2002

[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 samples

Maxi- . . Minimum Mean 

mum

Median

12323600-SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for bulk bed-sediment data: 1993-95, 1997-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

9

9

9

9

9

9

9

9

9

30.2 4.2 12.8

18.1 9.6 13.5

3,800 670 1,550

29,300 18,300 23,200

398 198 278

5,480 504 1,760

12.7 6.0 7.9

8.0 3.2 5.0

5,930 1,720 3,300

8.5

12.7

976

20,800

263

748

6.8

4.1

2,270

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

Period of record for bulk bed-sediment data: 1993, 1995-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

9

9

9

9

9

9

9

9

9

1.7 <.9 1 l.O

11.8 5.2 8.7

111 9 46

12,300 6,100 10,100

33 <10 1 13

2,100 209 890

9.2 4.8 6.0

1.3 <3 ! .7

303 93 154

H.2

9.2

32

9,600 l n

830

5.4

! .7

131

12323770- WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

Period of record for bulk bed-sediment data: 1995, 1997, 1999, 2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

4

4

4

4

4

4

4

4

4

1.5 <.8 \6

12.0 7.4 10.2

238 127 193

12,700 8,010 10,200

38 18 29

4,240 1,220 2,640

8.5 5.7 7.2

1.3 <.8 ! .9

275 146 183

! <.9

10.7

204

10,000

29

2,540

7.4

'1.0

155

12323800--CLARK FORK NEAR GALEN. MONT.

Period of record for bulk bed-sediment data: 1993-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

10

10

10

10

10

10

10

10

10

8.2 <.9 ! 3.9

23.7 4.2 15.5

902 223 496

31,300 9,930 20,400

158 41 81

9,490 900 3,490

15.2 4.9 9.0

5.2 .7 [ 2.1

1,280 417 725

'3.8

15.4

475

20,000

79

1,890

9.1

4.6

665

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

August 1993 through August 2002 (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: 1996-2002

7 3.3 <.9 '2.4

7 17.5 6.8 11.7

7 763 238 428

7 21,000 12,300 16,400

7 104 41 70

7 1,840 1,260 1,470

7 8.2 4.2 6.2

7 2.8 .8 4.6

7 787 339 523

4615591 12443301--CLARK FORK NEAR RACETRACK. MONT.

Period of record for bulk bed-sediment data: 1996-2002

7 6.6 <.9 ! 3.3

7 19.7 10.1 15.0

7 757 361 515

7 25,900 16,200 19,500

7 101 59 79

7 1,710 759 1.320

7 9.9 5.5 7.5

7 3.3 1.4 1 2.4

1 781 472 633

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: 1996-2002

7 9.2 1.5 4.2

7 21.1 13.0 17.2

7 1,000 244 541

7 25,400 16,400 22,200

7 115 47 79

7 4,930 825 1,880

7 12.8 5.5 8.6

7 4.4 <.8 ! 2.4

7 1,240 368 664

12324200--CLARK FORK AT DEER LODGE. MONT.

Period of record for bulk bed-sediment data: 1993-2002

10 7.8 1.0 J 3.2

10 29.2 12.1 19.1

10 906 281 495

10 25,000 13,200 19,600

10 112 45 77

10 2,530 607 1,220

10 12.3 7.7 10.0

10 3.9 <.7 4.9

10 1,060 456 637

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

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

3 <1.5 <1.2 l .l

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

'2.5

12.0

398

16,000

72

1,390

6.7

4.6

522

'2.7

14.7

475

18,200

78

1,350

7.3

'2.6

626

MONT.

3.0

17.3

577

23,500

88

1,630

9.0

^.8

604

! 2.2

19.6

412

19,700

78

1,040

10.1

4.6

564

'.7

32.1

19

17,300

14

333

11.7

'.8

73

80 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 1993 through August 2002 (Continued)

^ ... . Number of Constituent ,

samples

Maximum

Minimum Mean Median

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for bulk bed-sediment data: 1993-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

10

10

10

10

10

10

10

10

10

7.6

33.2

858

24,900

92

2,930

15.9

3.7

1,020

1.1

15.0

197

15,400

37

377

9.0

<.7

368

1 3.3

22.1

443

19,100

63

1,260

11.6

4.9

683

1 2.9

21.3

326

18,500

63

970

11.3

4.5

650

12331500-FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

10

10

10

10

10

10

10

10

10

3.8

13.9

40

15,700

120

3,200

8.0

5.8

429

<.2

4.9

16

8,630

51

1,150

4.5

2.5

178

4.8

9.8

24

12,900

77

2,170

5.9

4.3

277

4.6

10.9

22

13,400

80

2,220

5.9

4.4

279

12331800-CLARK FORK NEAR DRUMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

10

10

10

10

10

10

10

10

10

4.7

29.5

605

21,800

78

1,510

14.2

3.5

939

<1.6

6.9

114

12,100

31

409

7.7

.5

381

1 2A

18.4

260

16,000

47

980

10.3

4.6

577

I2.l

17.2

210

15,500

46

960

9.8

4.4

506

12334510-ROCK CREEK NEAR CLINTON. MONT.

Period of record for bulk bed-sediment data: 1993-99, 2001-02

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

9

9

9

9

9

9

9

9

9

<1.5

22.6

10

14,800

<13

270

10.2

<1.6

37

<.2

6.4

3

5,290

<3

72

3.6

.1

7

l

10.5

5

8,690

1 6

160

5.9

U

19

<.8

8.8

5

7,410

! 5

145

5.1

U

17

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

Period of record for bulk bed-sediment data: 1993-2002

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

10

10

10

10

10

10

10

10

10

4.9

23.8

336

19,100

67

1,470

14.0

2.9

769

.4

6.9

75

9,270

21

234

6.4

<.3

271

I 2.l

15.3

186

13,300

38

680

9.1

4.2

471

'2.1

16.0

184

13,000

37

565

8.6

4.0

493

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

August 1993 through August 2002 (Continued)

Constituent Number of 

samples

Maximum

Minimum Mean Median

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

12340000-BLACKFOOT RIVER NEAR BQNNER. MONT. 

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

5 <1.9 <.2 

19.2 6.7 

19 12 

17,000 10,300 

11 6 

650 179 

9.8 7.5

58 33

13.0

16

14,000

9

340

8.8

41

Ul.2 

12.5 

16

14,600 

10 

305 

9.3

35

12340500-CLARK FORK ABOVE MISSOULA. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Period of record for bulk bed-sediment data: 1997-2002

6

6

6

6

6

6

6

6

6

3.4

31.5

630

21,500

84

888

14.4

<3.3

1,210

<.8

9.7

43

11,500

7

228

8.2

<.4

145

4.8

17.0

178

16,000

31 

573 

10.4 

H.2 

427

16.1 

100 

16,100 

24 

562 

9.8 

!.8 

300

12353000-CLARK FORK BELOW MISSOULA. MONT.2

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Silver

Zinc

Period of record for bulk bed-sediment data: 1993-2002

10 3.0 <.2 1 .9

10

10 

10 

10

10 

10

10

10

12.7

77 

13,300 

23

560 

8.1

<1.9

183

4.4

16 

5,830

150 

3.5

<.3

58

7.7

40 

8,960

Ho

349 

5.4

1 .5

117

'.6

7.1

31 

8,840 

'8

366

5.2

'.5

111

Value determined by arbitrarily substituting one-half of the detection level for censored (<) values, when both uncensored and censored values are used in determining the mean and/or median. When all data are below the detection level, the median is determined by ranking the censored values in order of detection level. No mean is reported when all values are below the detection 

level.

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

82 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 2002

[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 morosa 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]

Number of

Constituent composite

samples

Maximum Minimum Mean Median

12323600--SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for biological data: 1992, 1994-95, 1997-2002

Brachwentrus SDD.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

5

5

5

5

5

5

5

5

12.5

5.9

846

1,190

21.5

817

2.1

995

5.8

.7

235

335

7.4

231

<.l

629

10.1

2.1

587

617

13.7

515

4.3

803

11.6

.9

592

469

13.8

503

4.6

815

Hvdroosvche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

6

6

6

6

6

6

6

6

9.7

8.0

1,090

2,660

47.2

1,160

3.6

1,380

4.1

1.0

269

689

19.0

180

.7

749

5.7

3.4

486

1,220

24.8

576

2.0

911

4.9

2.5

386

978

20.5

513

1.8

838

Hvdroosvche SDD.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

5

5

5

5

5

5

5

5

10.6

4.7

930

2,110

50.8

1,070

2.5

1,290

5.0

.6

352

1,270

34.7

712

1.6

1,070

8.7

1.7

768

1,730

40.4

933

2.2

1,140

8.8

.8

845

1,750

39.9

939

2.4

1,110

Hvdropsvche tana

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

6

6

6

6

6

6

6

6

9.2

11.5

456

1,520

21.0

969

1.8

1,070

4.8

.9

10.5

857

15.6

307

.7

760

6.8

4.5

236

1,100

18.6

634

1.4

961

6.9

1.8

298

1,050

18.3

675

1.6

1,020

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.

Period of record for biological data: 1992-2002

Hvdroosvche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

26

26

26

26

26

26

26

26

2.1

1.3

97.0

1,240

5.7

2,520

1.8

276

.2

.4

22.4

351

.3

491

.3

115

.7

.8

42.0

708

3.0

1,120

.8

179

.6

.8

39.3

733

2.9

873

.8

171

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

August 2002 (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

Period of record for biological data: 1992-2002

Hvdropsvche occidentalis

15 1.6 .2

15 1.7 .3

15 48.9 11.0 

15 2,960 372 

15 8.2 <1.7

15 3,410 1,200 

15 2.7 .7

15 211 141

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

.6

.9

32.6 

1,070 

'3.9

2,260 

1.4

178

1.1

.8

40.9 

680

2.9

725 

'.8

195

.4

1.0

30.3 

837 

'3.3

2,140 

1.3

178

.9

1.2

40.6 

693

4.7

678

'.5

177

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

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Period of record for biological data: 1995, 1997, 1999, 2002

Arctopsvche grandis

4 3.0 1.9

4 2.9 .8

4 102 78.3 

4 1,040 684 

4 5.6 3.0

4 3,560 1,340 

4 2.3 1.8

4 222 181

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.

2 1.1 .6

2 1.6 1.4

2 95.9 94.8 

2 1,220 1,150

2 5.9 5.2

2 3,390 956 

2 2.0 1.8

2 129 125

12323800--CLARK FORK NEAR GALEN. MONT.

Period of record for biological data: 1987, 1991-2002

Hvdropsvche cockerelli

25 2.7 .9

25 3.3 .8

25 181 48.7 

25 2,460 816

25 11.7 1.2

25 3,620 1,070 

25 3.1 .9

25 299 136

2.4

1.7

93.7 

839 

'4.3

2,250 

'2.1

196

.8

3.2

182 

2,010 

7.4

2,440 

3.2

169

.9

1.5

95.3 

1,190

5.6

2,170 

1.9

127

1.6

1.7

98 

1,380

7.5

2,240 

1.6

212

2.2

1.6

97.2 

815 

4.3

2,040

2.2

190

-

--

--

-

--

-

--

1.5

1.6

97 

1,340

7.6

2,290 

1.4

211

84 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 2002 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of

Constituent composite Maximum Minimum

samples

12323800-CLARK FORK NEAR GALEN. MONT.-Continued

Period of record for biological data: 1987, 1991-2002

Hvdropsvche morosa group

5 3.2 2.4

5 4.6 1.8

5 185 156

5 1,890 1,360

5 12.4 7.1

5 3,960 2,360

5 3.6 1.9

5 349 292

Hvdropsvche occidentalis

32 1.7 .6

32 6.6 .4

32 106 49.2

32 1,920 642

32 13.5 1.6

32 6,170 1,220

32 3.5 .8

32 286 168

Hvdropsvche tana

1

1

1

1

1

1

1

1

Hvdropsvche spp.

4 3.5 2.6

0

4 154 135

4 1,540 1,190

4 13.5 10.5

0

0

4 329 279

Mean

2.5

2.6

173

1,510

8.5

3,500

2.3

309

1.1

1.8

78.5

1,220

6.7

2,650

1.6

201

1.5

1.4

92.9

1,340

9.0

2,160

2.1

206

3.0

148

1,400

12.2

--

-

308

Median

2.4

2.2

175

1,430

7.9

3,860

2.1

303

1.1

1.4

75.5

1,180

6.3

2,290

1.6

196

-

-

--

--

--

-

--

3.0

-

152

1,450

12.4

-

--

313

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-2002

Claassenia sabulosa

1

1

1

1

1

1

1

1

Hvdropsvche cockerelli

11 2.8 1.4

11 2.6 .8

11 147 48.8

11 2,570 691

11 15.2 4.5

11 3,160 1,230

11 1.9 1.0

11 321 151

.3

1.9

70.1

189

1.2

238

.2

245

2.0

1.8

105

1,410

10.8

2,030

1.4

226

-

-

-

-

-

--

2.2

2.0

97.0

1,300

11.3

1,810

1.4

234

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

August 2002 (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

Number of

Constituent composite Maximum Minimum

samples

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

Period of record for biological data: 1996-2002

Hvdropsvche 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

Mean

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

4 225 143 183 

461559112443301-CLARK FORK NEAR RACETRACK. MONT.

Period of record for biological data: 1996-2002

Claassenia sabulosa

1

1

1 

1

1

1 

1

1

Hvdropsvche cockerelli

11 1.9 1.0

11 2.7 .6

11 109 50.0 

11 1,370 657

11 10.5 3.7

11 2,010 646 

11 1.4 .7

11 199 139

Hvdropsvche occidentalis

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

1.4

74.1 

919

6.4

1,450 

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

Median

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

-

-

--

1.4

1.1

70.6 

862

6.1

1,570 

1.0

171

1.2

1.8

93.5 

1,450 

9.7

2,100 

1.3

229

-

--

86 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 2002 (Continued)

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

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

Period of record for biological data: 1996-2002

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

1

1

1

-

--

--

Hvdroosvche cockerelli

9 1.6

9 1.7

9 143

9 1,290

9 8.9

9 1,230

9 1.9

9 192

Hvdropsvche occidental

17 1.7

17 2.8

17 163

17 1,660

17 13.8

17 3,990

17 2.4

17 292

Hvdropsvche spp.

2 1.7

2 2.1

2 140

2 1,610

2 13.2

2 1,150

2 1.6

2 212

-

-

--

-

-

.7

.4

60.7

552

3.5

487

.5

162

.7

.8

74.9

940

6.1

826

1.2

222

1.6

1.4

104

1,070

10.5

638

1.6

191

1.7

<2.4

30.8

340

<14.5

510

1.0

87

1.2

1.0

80.3

824

5.9

956

.9

177

1.1

1.8

94.9

1,410

11.0

2,430

1.5

246

1.6

1.8

122

1,340

11.8

892

1.6

202

-

-

-

-

-

--

1.3

.9

75.9

831

5.0

1,140

.7

178

1.1

1.8

87.5

1,500

11.4

2,290

1.4

236

-

--

-

-

--

--

-

12324200--CLARK FORK AT DEER LODGE. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1986-87

Arctoosvche grandis

2 2.4

2 1.0

2 69.1

2 676

2 <7.8

2 727

2 <1.7

2 178

HvdroDSvche cockerelli

23 2.3

23 3.2

23 136

23 3,340

23 18.2

23 1,490

23 2.4

23 391

, 1990-2002

<4.2

<1.3

34.9

537

3.8

380

<1.3

140

.6

.4

54.7

490

4.3

396

.3

132

1 2.2

^8

52.0

606

'3.8

554

1 -

159

1.4

1.6

94.1

1,140

9.5

805

1.2

186

-

-

-

--

--

-

1.3

1.7

97.7

1,040

8.9

701

1.0

185

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

August 2002 (Continued)

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

Period of record for biological data: 1986-87, 1990-2002

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel

Zinc

Hvdropsvche occidentalis

37 2.7

37 3.6

37 162 

37 2,060 

37 18.6

37 2,840 

37 12.9

37 329

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 

10.9

1,700 

1.8

238

1.6

145 

1,520 

8.8

195

1.3

1.9

109 

1,420 

10.7

1,730 

1.4

236

1.6

-

Ill 

1,240

5.7

197

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

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

15 .7

15 1.6

15 14.2 

15 677

15 1.3

15 1,140 

15 1.4

15 214

Claassenia sabulosa

1 .5

7 .9

7 36.1 

7 319

7 90.5 

7 .7

7 233

Hvdropsvche cockerelli

1

1

1 

1

1

1 

1

1

Hvdropsvche occidentalis

2 <.l

2 2.3

2 15.2 

2 1,340

2 2.3

2 554 

2 1.1

2 137

.2

.6

9.0

177

.5

318 

.4

113

.1

.3

20.0 

98

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

I 2.l

494 

1.0

124

.4

.8

13.0 

313

.8

551 

.6

162

.2

.7

30.3 

156

61.6 

.5

202

-

-

--

-

--

88 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 2002 (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: 1992-2002

Arctopsvche grandis

29 6.6 1.1

29 3.3 .4

29 129 21.4

29 2,360 339

29 10.9 2.0

29 1,580 592

29 1.8 .2

29 326 163

Claassenia sabulosa

20 3.5 .3

20 1.6 .3

20 81.7 33.0

20 567 63.0

20 1.8 .5

20 279 50.6

20 .7 .2

20 351 166

H\drovs\che cockerelli

19 2.6 .6

19 4.7 .5

19 188 17.1

19 3,250 522

19 16.2 2.4

19 1,670 538

19 2.3 .3

19 249 106

Hvdropsvche 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, 1992-2002

Arctoosvche qrandis

39 .8 .1

39 4.7 .3

39 21.7 8.9

39 2,460 412

39 17.5 3.7

39 2,480 424

39 2.7 .6

39 275 93

Mean

2.5

1.3

48.9

764

4.1

876

.8

214

1.3

.6

55.8

202

1.1

125

.3

261

1.6

2.1

77.8

1,270

7.6

841

1.3

191

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

1.8

14.9

1,340

8.9

1,480

1.4

196

Median

2.0

1.0

39.1

518

3.6

861

.6

195

.9

.5

54.9

192

1.1

102

.3

260

1.4

1.9

65.1

930

5.8

713

1.2

200

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

15.2

1,300

7.8

1,360

1.3

192

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

August 2002 (Continued)

12331500--FLINT CREEK NEAR DRUMMOND. MONT.-Continued

Period of record for biological data: 1986, 1992-2002

Hvdropsvche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

11

11

11

11

11

11

11

11

.9

4.0

28.3

3,720

28.4

2,690

2.7

208

.1

.9

9.5

996

3.1

401

.9

85

.4

1.9

17.7

2,150

14.7

1,340

2.0

169

.4

1.8

18.0

2,020

16.2

1,220

2.2

182

Hvdropsvche occidentals

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

1

1

1

1

1

1

1

2

2

2

2

2

2

2

2

1.1

17.6

27.3

2,990

29.8

4,790

6.9

243

Hvdropsvche SDD.

-

-

-

--

-

-

-

--

Hvdropsvche 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

! -

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

-

-

--

--

-

-

--

-

-

-

--

-

-

-

--

12331 800--CL ARK FORK NEAR DRUMMOND. MONT.

Period of record for biological data:

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

32

32

32

32

32

32

32

32

36

36

36

36

36

36

36

36

Arctopsvche grandis

3.8

2.5

89.2

1,660

11.8

2,010

1.9

308

Claassenia sabulosa

2.8

3.3

165

387

2.9

410

1.1

567

1986, 1991-2002

.5

.2

16.9

240

2.1

462

.2

142

.2

.1

18.0

45.4

.2

33.1

.1

103

1.5

.9

34.4

610

4.7

859

.7

194

1.2

.7

65.2

161

1.0

158

.3

274

1.3

1.0

28.7

552

4.3

737

.6

190

1.1

.6

53.8

135

.8

135

.2

252

90 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 2002 (Continued)

Number of 

Constituent composite Maximum Minimum 

samples

Mean Median

12331800--CLARK FORK NEAR DRUMMOND. MONT.--Continued

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1986, 1991-2002

Hvdropsvche cockerelli

29 2.3 .6

29 3.5 .4

29 156 30.0

29 2,500 506

29 15.0 5.1

29 1,680 549

29 2.0 .5

29 248 134

Hvdropsvche morosa group

6 1.3 1.1

6 2.8 1.9

6 57.4 50.2

6 1,730 1,380

6 10.8 7.0

6 1,940 1,260

6 1.7 1.3

6 250 227

Hvdropsvche occidentalis

16 2.0 .7

16 8.1 .4

16 118 13.3

16 2,060 424

16 14.0 2.9

16 2,920 619

16 2.4 .5

16 293 157

Hvdropsvche spp.

1

0

1

1

1

0

0

1

123345 10--ROCK CREEK NEAR CLINTON. MONT.

Period of record for biological data: 1987, 1991-99, 2001-02

Arctopsvche erandis

38 .4 .06

38 2.9 .5

38 15.7 4.7

38 1,090 191

38 1.1 .05

38 454 113

38 1.8 .2

38 189 84

Claassenia sabulosa

19 .3 .05

19 1.8 .1

19 40.7 18.1

19 129 49.8

19 1.0 .1

19 76.3 15.7

19 .9 .1

19 264 144

1.2

1.6

61.0

1,190

8.8

952

1.2

194

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

.2

1.2

8.6

594

U

259

.9

129

.2

.7

28.8

92.7

.4

34.6

.4

198

1.0

1.5

51.1

984

8.2

901

1.1

186

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

-

-

-

-

-

-

-

--

.2

1.0

8.5

547

U

260

1.0

134

.2

.6

28.5

102

.3

32.9

.3

192

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

August 2002 (Continued)

Number of

Constituent composite Maximum Minimum

samples

Mean Median

123345 10--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, 1991-99, 2001-02

Hvdropsvche cockerelli

3 <.2 <2

3 1.0 .9

3 13.1 6.0

3 609 485

3 <1.1 <1.1

3 258 192

3 .9 .4

3 99 82

Hvdropsvche occidentalis

4 <1.0 <-3

4 2.4 .9

4 17.6 9.6

4 752 520

4 6.0 1.2

4 268 169

4 1.7 .6

4 144 99

Hvdropsvche spp.

3 .3 <.5

3 2.1 1.1

3 16.2 11.6

3 1,140 837

3 <3.1 <1.8

3 462 299

3 1.3 .8

3 135 117

1 -

.9

8.6

530

1 ~

219

.6

89

! ~

1.6

12.0

642

3.0

228

1.2

121

J .2

1.6

14.3

1,000

!--

399

1.1

126

<.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

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1986, 1991-2002

Arctopsvche erandis

42 2.7 .6

42 4.1 .6

42 125 20.1

42 2,870 420

42 13.2 2.1

42 893 351

42 2.7 .4

42 276 152

Claassenia sabulosa

26 2.5 .3

26 2.0 .2

26 79.2 38.3

26 181 58.6

26 1.6 .2

26 139 37.2

26 .6 .1

26 283 144

Hvdropsvche cockerelli

28 1.7 .5

28 8.0 .9

28 118 26.4

28 2,530 688

28 12.1 2.2

28 788 426

28 2.6 .6

28 228 148

1.3

1.7

40.1

1,030

4.7

637

1.2

203

1.1

.7

57.0

105

.6

76.2

.2

221

.9

2.0

49.7

1,270

5.5

599

1.3

188

.9

1.5

33.9

879

4.2

637

.9

198

.9

.6

53.9

103

.6

68.5

.2

226

.7

1.6

43.9

1,160

5.2

570

1.2

184

92 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 2002 (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, 1991-2002

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

6.6

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

20

20

20

20

20

20

20

20

1

1

1

1

1

1

1

1

1.8

3.2

102

2,310

14.2

1,600

3.2

416

Hvdropsvche spp.

-

-

-

--

.3

.6

34.1

472

3.0

454

.6

145

--

-

-

-

--

.9

1.9

50.1

1,220

6.7

817

1.2

208

1.3

2.4

84.1

1,800

<7.8

537

1.3

171

.9

1.7

44.9

1,130

5.7

728

1.1

200

-

-

-

--

-

--

-

-

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 grandis

.4

1.8

13.4

1,230

2.1

517

1.2

143

Claassenia sabulosa

.2

.9

88.5

199

.6

127

.3

329

1993, 1996, 1998, 2000

<.l

.8

9.9

108

.5

286

.8

123

.1

.3

19.0

46.2

.4

26.3

.1

117

'.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

Hvdroosvche 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

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

August 2002 (Continued)

Number of 

Constituent composite Maximum Minimum 

samples

Mean Median

12340000--BLACKFOOT RIVER NEAR BONNER. MONT.-Continued

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

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

Hvdropsyche spp.

1

1

1

1

1

1

1

1

12340500-CLARK FORK ABOVE MISSOULA. MONT.

Period of record for biological data: 1997-2002

Arctopsvche erandis

19 1.8 .4

19 3.0 .6

19 77.6 19.5

19 2,340 476

19 6.8 1.2

19 1,210 476

19 2.0 .5

19 260 133

Claassenia sabulosa

9 2.0 .2

9 1.1 .3

9 71.7 33.0

9 402 95.3

9 3.1 .5

9 683 75.2

9 <.5 <3

9 363 191

Hvdropsvche cockerelli

9 1.3 .4

9 4.1 1.8

9 96.1 29.9

9 3,590 1,400

9 6.3 4.2

9 1,470 781

9 2.4 1.4

9 226 156

Hvdropsvche occidentalis

6 1.1 .4

6 3.2 2.1

6 76.5 30.3

6 2,400 1,450

6 7.7 4.0

6 2,460 939

6 2.3 1.6

6 232 192

12353000--CLARK FORK BELOW MISSOULA. MONT.2

Period of record for biological data: 1986, 1990-2002

Arctopsvche grandis

25 1.5 .2

25 2.7 .5

25 38.0 9.4

25 1,590 343

25 3.9 .9

25 1,090 511

25 1.6 .4

25 217 106

.6

1.6

13.9

1,140

2.9

525

2.8

132

.7

1.4

32.2

984

3.4

831

1.1

186

.7

.7

50.4

243

H.3

237

U

275

.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

1.3

21.8

836

1.9

714

1.0

155

-

--

--

-

-

--

--

.6

1.4

27.5

895

3.1

835

.9

177

.4

.7

46.8

246

h.l

136

U

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

.7

1.4

22.0

813

1.9

711

1.0

152

94 Water-quality, bed-sediment, and biological data (October 2001 through September 2002) and statistical summaries of data for streams in the 

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

August 2002 (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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

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

Period of record for biological data: 1986,1990-2002

Claassenia sabulosa

39 1.3 .1 .5

39 1.2 .05 .5

39 74.8 31.1 48.2

39 239 66.6 113

39 1.3 .1 .4

39 168 48.9 102

39 .3 .1 .2

39 286 146 215

Hvdropsvche cockerelli

38 1.1 .2 .5

38 3.4 .8 1.9

38 54.1 12.4 31.4

38 2,220 584 1,380

38 6.6 1.2 2.6

38 1,210 353 746

38 1.9 .5 1.3

38 187 77.4 148

Hvdropsvche occidentalis

16 1.1 .2 .5

16 3.5 .1 1.4

16 38.2 16.0 24.4

16 1,420 482 956

16 4.2 .7 2.1

16 1,460 491 849

16 2.2 .5 1.0

16 193 112 144

Hvdroosvche SDD.

.4

.5

46.9

108

.3

99

.2

210

.6 

1.9

32.0

1,390

2.4

673

1.3

154

.4

1.5

21.6

985

1.9

825

.9

147

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

.5

.8

20.8 

894

1.1

I - -- 756 

1 - - 1.1

1 - - 124

--

-

~

-

~

-

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.

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

TABLE 24 95