In cooperation with the

U.S. ENVIRONMENTAL PROTECTION AGENCY

Water-Quality, Bed-Sediment, and Biological 

Data (October 1999 Through September 2000) 

and Statistical Summaries of Data for Streams in 

the Upper Clark Fork Basin, Montana

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

Carlos Primo C. David

Open-File Report 01-379

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 1999 Through September 2000) 

and Statistical Summaries of Data for Streams in 

the Upper Clark Fork Basin, Montana

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

Carlos Primo C. David

Open-File Report 01-379

U.S. Department of the Interior 

U.S. Geological Survey
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

Helena, Montana 

November 2001

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 1999 through September 2000........ 17

5-7. Daily streamflow and suspended-sediment data, October 1999 through September 2000, for:

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

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

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

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

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

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

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

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

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

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

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

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

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

14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, September 2000 50

15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, September 2000............ 51

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

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

CONTENTS iii
TABLES (Continued)

Page

Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, September 2000................................. 54

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

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

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

through September 2000 ............................................................................................................................ 58

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

August 1986 through September 2000....................................................................................................... 73

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

1993 through September 2000 ................................................................................................................... 78

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

through September 2000 ............................................................................................................................ 83

CONVERSION FACTORS, ABBREVIATED WATER-QUALITY UNITS, AND ACRONYMS

Multiply By To obtain

cubic foot per second (ft /s)

foot (ft)

gallon (gal)

gallon (gal)

inch (in.)

inch (in.)

mile (mi)

ounce (oz)

part per million

square mile (mi )

ton per day (ton/d)

0.028317

0.3048

3.785

3,785

25.4

25,400

1.609

28.35

1

2.59

907.2

cubic meter per second

meter (m)

liter (L)

milliliter (mL)

millimeter (mm)

micrometer (um)

kilometer

gram (g)

microgram per gram (U£/g)

square kilometer

kilogram per day

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

°F = 9/5 (°C) + 32

Abbreviated water-quality units used in this report:

lig/g micrograms per gram

lig/L micrograms per liter

Hg/mL micrograms per milliliter

liS/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

LRL laboratory reporting levels

LT-MDL long-term method detection levels

NWQL USGS National Water Quality Laboratory, Denver, Colo.

RSD relative standard deviation

SRM standard reference material

USGS U.S. Geological Survey

iv Water-Quality, Bed-Sediment, and Biological Data (October 1999 through September 2000) and Statistical Summaries of Data for Streams in 

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

1999 through September 2000) and Statistical Summaries of 

Data for Streams in the Upper Clark Fork Basin, Montana

By Kent A. Dodge, Michelle I. Hornberger 1 , and Carlos Primo C. David1

Abstract

Water, bed sediment, and biota were sampled in 

streams from Butte to below Missoula as part of a 

program to characterize aquatic resources in the upper 

Clark Fork basin of western Montana. Sampling 

stations were located on the Clark Fork and major 

tributaries. Water-quality data were obtained 

periodically at 15 stations during October 1999 through 

September 2000 (water year 2000). Data for 14 bedsediment and 14 biological stations were obtained in 

September 2000. The primary constituents analyzed 

were trace elements associated with tailings from 

historical mining and smelting activities.

Water-quality data include concentrations of 

selected major ions, trace elements, and suspended 

sediment in stream samples. Daily values of 

streamflow, suspended-sediment concentration, and 

suspended-sediment discharge are given for three 

stations. Bed-sediment data include trace-element 

concentrations in the fine-grained and bulk fractions. 

Biological data include trace-element concentrations in 

whole-body tissue of aquatic benthic insects. Qualityassurance data are reported for analytical results of 

water, bed sediment, and biota. Statistical summaries 

of water-quality, bed-sediment, and biological data are 

provided for the period of record at each station since 

1985.

INTRODUCTION

The Clark Fork originates near Warm Springs in 

western Montana at the confluence of Silver Bow and 

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

of stream from Silver Bow Creek in Butte to the Clark 

Fork at Milltown Reservoir, six major tributaries enter: 

Blacktail Creek, Warm Springs Creek, Little Blackfoot 

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

r\

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 had 

been prevalent land uses in the upper basin for more 

than one hundred years, but are now largely 

discontinued.

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

downstream since the late 1800's and redeposited in 

stream channels, on flood plains, and in the Warm 

Springs Ponds and Milltown Reservoir. The widely 

dispersed tailings continue to be eroded, transported, 

and redeposited along the stream channel and flood 

plain, especially during high flows. The occurrence of 

trace elements in elevated concentrations can pose a 

risk to aquatic biota and human health because they 

can accumulate to potentially toxic levels.

Concern about the potential toxicity of tailings to 

aquatic biota and human health has resulted in a 

comprehensive effort by State, Federal, and private 

entities to characterize the aquatic resources in the 

upper Clark Fork basin to guide and monitor remedial 

cleanup activities. A long-term data base was 

considered necessary to detect trends over time in order 

to evaluate the effectiveness of remediation. Waterquality data have been collected by the U.S. Geological 

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

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

Abstract
MONTANA

, Helena 

Study area

Base from U.S. Geological 

Survey, State base map, 

1:1,000,000,1966

EXPLANATION

12324200 STATION NUMBER

461903112440701 MISCELLANEOUS SITE NUMBER 

STREAMFLOW STATION TYPE 

A Continuous record 

Z\ Periodic measurement

WATER QUALITY, BED SEDIMENT, AND 

BIOTA STATION TYPE

XJ Periodic water quality 

^, Daily suspended sediment 

V~ Once-annual bed sediment 

~~y Once-annual biota

461903112440701-y461559112443301 -y461415112450801irST

k 12323800

e j.1

f

IF

12323770* -^4-12323750

W 12323600

10

12323250'

12323230

20 MILES

10 20 KILOMETERS

Figure 1. Location of study area.

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

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

and others, 1996, 1997, 1998, 1999,2000). Traceelement data for bed sediment and biota (aquatic 

benthic insects) have been collected intermittently 

since 1986 at selected sites as part of studies on bedsediment contamination and bioaccumulation of 

metals conducted by the USGS National Research 

Program (Axtmann and Luoma, 1991; Axtmann and 

others, 1997; Cain and others, 1992, 1995; Hornberger 

and others, 1997). In March 1993, an expanded 

sampling program for water, bed sediment, and biota 

was implemented 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 

14 bed-sediment and 14 biological stations in the upper 

Clark Fork basin collected from October 1999 through 

September 2000 (water year 2000). Quality-assurance 

data are presented for water quality, bed sediment, and 

biota. Statistical summaries also are provided for 

water-quality, bed-sediment, and biological data 

collected since 1985.

Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
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). 

Mainstem sampling sites were selected to divide the 

upper Clark Fork into reaches of relatively uniform 

length, with each reach encompassing either a major 

tributary or depositional environment (Warm Springs 

Ponds and Milltown Reservoir). Tributaries were 

sampled to describe water-quality characteristics for 

major hydrologic sources in the upper basin and to 

provide reference comparisons to the mainstem for bed 

sediment and biota. Water-quality data were obtained 

periodically at 15 stations; daily suspended-sediment 

data were obtained at 3 of these stations. Traceelement data for 14 bed-sediment and 14 biological 

stations were obtained once-annually (table 1).

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 2000 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 2000 are given in tables 21 -24 at the back of 

the report.

Quality assurance of data was maintained through 

the use of documented procedures designed to provide 

environmentally representative data. Acceptable 

performance of the procedures was verified with 

quality-control samples that were collected 

systematically to provide a measure of the accuracy, 

precision, and bias of the environmental data and to 

identify problems associated with sampling, 

processing, or analysis.

WATER-QUALITY DATA

Water-quality data consist of measurements of 

physical properties and concentrations of chemical and 

physical constituents analyzed in stream samples. 

Samples were collected 6 to 8 times per year on a 

schedule designed to describe seasonal and hydrologic 

variability.

Methods

Cross-sectional water samples were collected 

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

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

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

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

entire flow through the cross section of a stream. 

Sampling equipment consisted of standard USGS 

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

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

and equipped with nylon nozzles.

Onsite measurements of air and water 

temperature, specific conductance, and pH were made 

during collection of periodic water-quality samples. 

Onsite sample processing, including filtration and 

preservation, was performed according to procedures 

described by Knapton (1985), Ward and Harr (1990), 

and Horowitz and others (1994). Instantaneous 

streamflow at the time of water sampling was 

determined at all stations, either by direct measurement 

or from stage-discharge rating tables (Rantz and others, 

1982).

Water samples were analyzed for the constituents 

listed in table 2 by the USGS National Water Quality 

Laboratory (NWQL) in Denver, Colo. The trace 

elements arsenic, cadmium, copper, iron, lead, 

manganese, and zinc were analyzed for both dissolved 

and total-recoverable concentrations. Analytical 

methods are described by Fishman and Friedman 

(1989) and Fishman (1993).

Cross-sectional water samples also were 

collected for analysis of suspended sediment whenever 

periodic water-quality samples were collected. These 

samples were analyzed for suspended-sediment 

concentration and the percentage of suspended 

sediment finer than 0.062-mm diameter (silt size and 

smaller) by the USGS sediment laboratory in Helena, 

Mont., according to methods described by Guy (1969) 

and Lambing and Dodge (1993).

At the three daily suspended-sediment stations 

(table 1), suspended-sediment samples were collected 

2 to 8 times per week. These samples were collected 

by local contract observers using the depth-integration 

method at a single vertical near mid-stream. The 

samples were analyzed for suspended-sediment

SAMPLING LOCATIONS AND TYPES OF DATA
M

li

23j»

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

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

B?

I

i ra

c 

aa'

a I

Station number

(fls- i)

12323230

12323250

123236001232375012323770

12323800

461415112450801461559112443301461903112440701

12324200

12324590123246801233150012331 ROO

12334510

12334550

12340000

1234050012353000

Station name

Blacktail Creek at Harrison Avenue, at 

Butte

Silver Bow Creek below Blacktail Creek, at 

ButteSilver Bow Creek at OpportunitySilver Bow Creek at Warm SpringsWarm Springs Creek at Warm Springs

Clark Fork near GalenClark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

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

Little Blackfoot River near Garrison

Clark Fork at Goldcreek

Flint Creek near DrummondClark 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 -- 1 0/78-P

10/72-P1 0/77-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-P03/93-P07/88-P --~03/85-P03/85-P03/93-P03/85-P03/93-P03/85-P03/85-P03/85-P

07/86-P-'

03/85-09/95

Daily suspended 

sediment

- 

03/93-09/9504/93-09/95 ----- 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 sediment

07/92-P

07/92-P

08/95,08/97,08/99

08/87, 

08/9 1-P

08/96-P08/96-P

08/96-P

08/86, 08/97. 

08/90-P

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

08/98

07/92-P

08/86, 08/89, 

0-/92-P

08/86, 08/87, 

08/9 1-P

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

08/91-99

08/86, 

08/9 1-P

08/86. 08/87. 

08/91, 

08/93-96, 08/98-P

08/97-P

08/86, 

OH/90-P

Bulk bed sediment2 ---- 08/93-08/95, 

08/97-P

08/93, 

08/95-P

08/95,08/97,08/99

08/93-P

08/96-P08/96-P

08/96-P08/93-P

08/94, 08/98

08/93-P08/93-P

08/93-P

08/93-99

08/93-P

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

08/97-P

08/93-P

Biota2

~-- 07/92, 08/94, 

08/95, 08/97-P

07/92-P

08/95, 08/97, 08/99

08/87, 

08/91-P08/96-P08/96-P

08/96-P

08/86, 08/87, 

08/90-P

08/87, 08/94 

08/98

07/92-P

08/86, 

07/92-P

08/86. 

08/91-P

08/87, 

08/91-99

08/86, 

08/91-P

08/86, 08/87, 

08/91,08/93, 

08/96, 08/98, 09/00

08/97-P

08/86, 

08/90-P

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

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

Laboratory analyses of trace elements.

^Prior to October 1989, water-quality data for Clark Fork above Missoula only included suspended-sediment data. 4Bed sediment and biota sampled about 30 miles downstream from streamflow-gaging station to conform to previous sampling location. Water-quality sampling discontinued in 1995.
Table 2. Properties measured onsite and constituents analyzed in samples of water, 

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

Water

Property

Streamflow

Specific conductance

pH

Temperature

Constituent

Hardness

Calcium

Magnesium

Arsenic

Cadmium

Copper

Iron

Lead

Manganese

Zinc

Suspended sediment

Bed sediment

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Biota

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

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 1999 through September 

2000 (water year 2000) 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 2000 at the three daily suspendedsediment stations are given in tables 5 through 7. 

Monthly descriptive statistics for each parameter are 

provided along with totals for the annual discharge of 

water and suspended sediment.

Quality Assurance

Quality-assurance procedures used for the 

collection and field processing of water-quality 

samples are described by Ward and Harr (1990), 

Knapton and Nimick (1991), Horowitz and others 

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

Glysson (1999). Standard procedures used by the 

NWQL for internal sample handling and quality 

assurance are described by Friedman and Erdmann 

(1982), Jones (1987), and Pritt and Raese (1995). 

Quality-assurance procedures used by the Montana 

District sediment laboratory are described by Lambing 

and Dodge (1993).

The quality of analytical results reported for 

water-quality samples was evaluated by quality-control 

samples that were submitted from the field and 

analyzed concurrently in the laboratory with routine 

samples. These quality-control samples consisted of 

replicates, spikes, and blanks which provide 

quantitative information on the precision and bias of 

the overall field and laboratory process. Each type of 

quality-control sample was submitted at a proportion 

equivalent to about 5 percent of the total number of 

water-quality samples. Therefore, the total number of 

quality-control samples represented about 15 percent 

of the total number of water-quality samples.

In addition to quality-control samples submitted 

from the field, internal quality-assurance practices at 

the NWQL are performed systematically to provide 

quality control of analytical procedures (Pritt and 

Raese, 1995). These internal practices include 

analyses of quality-control samples such as calibration 

standards, standard reference water samples, replicate 

samples, deionized-water blanks, or spiked samples at 

a proportion equivalent to at least 10 percent of the

WATER-QUALITY DATA
sample load. The NWQL participates in a blindsample program where standard reference water 

samples prepared by the USGS Branch of Quality 

Systems are routinely inserted into the sample line for 

each analytical method at a frequency proportional to 

the sample load. The laboratory also participates in 

external evaluation studies twice-yearly with the U.S. 

Environmental Protection Agency, the Canadian 

Center for Inland Water, and the Branch of Quality 

Systems to assess analytical performance.

Replicate data can be obtained in different ways 

to provide an assessment of precision (reproducibility) 

of analytical results. Replicate samples are two or 

more samples considered to be essentially identical in 

composition. Replicate samples can be obtained in the 

field (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 dataquality objectives are used to evaluate whether 

sampling and analytical procedures are producing

6 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

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

Data-quality objectives

Detectability

Constituent

Calcium, dissolved

Magnesium, dissolved

Arsenic, total recoverable

Arsenic, dissolved

Cadmium, total recoverable

Cadmium, dissolved

Copper, total recoverable

Copper, dissolved

Iron, total recoverable

Iron, dissolved

Lead, total recoverable

Lead, dissolved

Manganese, total recoverable

Manganese, dissolved

Zinc, total recoverable

Zinc, dissolved

Sediment, suspended

Sediment, suspended (percent finer than 0.062 mm)

Precision

Maximum relative 

Laboratory standard deviation of 

reporting laboratory replicate 

level1 analyses, 

in percent

0.02

.01

3

.9-2

.1

.1

1

1

20

10

1

1

3

1

1-31

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 2000.

environmentally representative data in a consistent 

manner. Data that did not meet the objectives were 

evaluated for acceptability, and corrective action was 

taken, when appropriate.

During water year 1999, the NWQL began 

implementation of a new, statistically based convention 

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

Quality-control data are collected on a continuing basis 

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

values are re-evaluated each year and, consequently, 

may change from year to year. The methods are 

designed to limit the possible occurrence of a false 

positive or false negative error to 1 percent or less. 

Accordingly, concentrations are reported as less than 

the LRL for samples in which the analyte was either not 

detected or did not pass identification criteria. 

Analytes that are detected at concentrations between

the LT-MDL and LRL and that pass identification 

criteria are estimated. Estimated concentrations are 

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

be used with the understanding that their uncertainty is 

greater than that of data reported without the "E" 

remark code.

The precision of analytical results for a 

constituent can be determined by estimating a standard 

deviation of the differences between replicate 

measurements for several sets of samples. These 

replicate measurements may consist either of 

individual analyses of a pair of samples considered to 

be essentially identical (field replicates) or multiple 

analyses of an individual sample (laboratory 

replicates). The differences in concentration between 

replicate analyses can be used to estimate a standard 

deviation according to the following equation (Taylor, 

1987):

WATER-QUALITY DATA
s =

2k

(1)

where

S = standard deviation of the difference 

in concentration between 

replicate analyses,

d = difference in concentration between 

each pair of replicate analyses, 

and

k - number of pairs of replicate analyses. 

Precision also can be expressed as a relative 

standard deviation (RSD). in percent, which is 

computed from the standard deviation and the mean 

concentration for all the replicate analyses. Expressing 

precision relative to a mean concentration standardizes 

comparison of precision among individual 

constituents. The RSD, in percent, is calculated 

according to the following equation (Taylor, 1987):

where

RSD = ^ X 100 (2)

RSD= relative standard deviation,

S = standard deviation, and

x = mean of all replicate concentrations.

Paired analyses of field replicates are presented in 

table 8. The precision estimated for each constituent 

based on these paired results, which include both field 

and laboratory sources of variability, is reported in 

table 9. Statistics for precision of field-replicate 

analyses were based on the values reported in table 8, 

which are rounded to standard USGS reporting levels 

for the particular constituent and its analytical method 

(Timme, 1994).

Data-quality objectives for precision are not 

directly applicable to field replicates because of the 

inability to determine whether the variability results 

from field sample collection and processing, or 

laboratory handling and analysis. However, a 

statistical calculation of precision for the field 

replicates is provided in table 9 to illustrate overall

reproducibility of environmental data that incorporates 

both field and laboratory sources of variability. The 

data-quality objective used to evaluate precision of 

results for field replicates was a maximum relative 

standard deviation of 20 percent. Precision estimates 

for the field replicate analysis were within the 20- 

percent relative standard deviation limit for all 

constituents except dissolved copper. The exceedance 

for dissolved copper was a result of poor comparison in 

one replicate sample set; therefore, results for field 

replicates indicated acceptable reproducibility.

Analytical precision for chemical constituents 

based on replicate laboratory analyses of individual 

samples, which includes only laboratory sources of 

variability, is reported in table 10. Statistics for 

analytical precision of laboratory-replicate analyses 

are based on unrounded values stored in laboratory data 

files. The data-quality objective for analytical 

precision of laboratory-replicate analyses is a 

maximum relative standard deviation of 20 percent. 

Precision estimates for laboratory-replicate analyses 

(table 10) were within the 20-percent relative standard 

deviation limit for all constituents except totalrecoverable cadmium and dissolved lead. The 

exceedance of both constituents was an artifact of 

comparing analytical results that were below 

laboratory equipment detection capabilities.

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. 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

Spike recovery, in percent =

spiked sample concentration - unspiked sample concentration 

spike concentration xlOO (3)

8 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
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 

97.4 to 107.8 percent. The mean spike recovery for 

spiked stream samples ranged from 94.6 to 105.3 

percent. The 95-percent confidence intervals (Taylor. 

1987) for the mean of spike recovery for each 

constituent analyzed in stream samples (table 12) did 

not exceed a 25-percent deviation from an expected 

100-percent recovery.

High or low bias is indicated if the confidence 

interval does not include 100 percent recovery. All 

laboratory-spiked stream samples (table 12) had 

confidence intervals for percent recovery that included 

100 percent, except total-recoverable lead which 

ranged from 103 to 108 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 laboratory reporting level 

(LRL) for the analytical method indicates that the 

entire process of sample collection, field processing, 

and laboratory analysis is presumably free of 

significant contamination. If detectable concentrations 

in field blanks were equal to or greater than twice the 

LRL (typical measurement precision at the detection 

level), the concentrations were noted during data 

review. Analytical results from the field blank for the 

next sample set were evaluated for a consistent trend 

that may indicate systematic contamination. Sporadic, 

infrequent exceedances of twice the LRL probably 

represent random contamination or instrument 

calibration error that is not persistent in the process and 

which is not likely to cause significant positive bias in 

a long-term record of analytical results. However, if 

concentrations for a particular constituent exceed twice 

the LRL in field blanks from two consecutive field 

trips, blank samples are collected from individual 

components of the processing sequence and are 

submitted for analysis in order to identify the source of 

contamination.

Constituent concentrations in field blanks were 

almost always less than the LRL. Total-recoverable

zinc had two consecutive exceedances of twice the 

LRL. Because the exceedances were only slightly 

higher than the LRL, occurred at the time of an 

analytical method change, and were followed by nondetectable concentrations in subsequent blanks, these 

occurrences were considered sporadic, and not 

persistent in the field or analytical process. Therefore, 

the analytical results for field blanks indicate no 

systematic contamination that would bias the reported 

water-quality data for stream samples.

BED-SEDIMENT DATA

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

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

Bed-sediment samples are collected once-annually 

during low, stable flow conditions to facilitate data 

comparisons among years.

Methods

Bed-sediment samples were collected in 

September 2000 using protocols described by E.V. 

Axtmann (U.S. Geological Survey, written commun., 

1994). Samples were collected from the surfaces of 

streambed deposits in low-velocity areas near the edge 

of the stream using an acid-washed polypropylene 

scoop. Whenever possible, samples were collected 

from both sides of the stream. Three composite 

samples of fine-grained bed sediment and two 

composite samples of bulk bed sediment were 

collected at each site.

Individual samples of fine-grained bed sediment 

were collected by scooping material from the surfaces 

of three to five randomly selected deposits along pool 

or low-velocity areas. The three to five individual 

samples were combined to form a single composite 

sample. This collection process was repeated three 

times to obtain three composite samples. Each 

composite sample was wet-sieved onsite through a 

0.064-mm nylon-mesh sieve using ambient stream 

water. The fraction of bed sediment in each composite 

sample that was finer than 0.064 mm was transferred to 

an acid-washed 500-mL polyethylene bottle and 

transported to the laboratory on ice.

Individual samples of bulk bed sediment also 

were collected by scooping material from the surfaces

BED-SEDIMENT DATA
of three to five randomly selected deposits. 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 acidwashed polyethylene bottle and transported to the 

laboratory on ice.

Bed-sediment samples were prepared for analysis 

at the USGS National Research Program laboratory in 

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

using an acid-washed ceramic mortar and pestle. 

Duplicate aliquots of approximately 0.6 g of sediment 

from each of the three composite fine-grained bed 

sediment samples were digested using a hot, 

concentrated nitric acid reflux according to methods 

described by Luoma and Bryan (1981). Two aliquots 

were similarly digested from the single composite 

sample of bulk bed sediment. After a digestion period 

of up to several weeks, the aliquots were evaporated to 

dryness on a hot plate. The dry residue was redissolved 

with 20 mL of 0.6 N (normal) hydrochloric acid. The 

reconstituted aliquots then were filtered through a 0.45- 

|J,m filter using a syringe and in-line disposable filter 

cartridge. The filtrate was subsequently diluted to 

either a 1:5 or 1:10 ratio with 0.6 N hydrochloric acid. 

These final solutions were 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 September 2000 are summarized in 

tables 14 and 15, respectively. Liquid-phase 

concentrations, in |j,g/mL, that were analyzed in the 

reconstituted aliquots of digested bed sediment were 

converted to solid-phase concentrations, 

in |J.g/g, using the following equation:

_ 1-lg/mL x volume of digested sample, in mL 

dry weight of sample, in g x dilution ratio

The reported solid-phase concentrations in table 

14 and 15 are the means of all analyses of replicate 

aliquots from each composite sample collected at the 

site. Because the conversion from liquid-phase to 

solid-phase concentration is dependent on both the 

dilution ratio and the dry weight of the sample, 

minimum reporting levels for some trace elements may 

differ among stations and among years.

Quality Assurance

The protocols for field collection and processing 

of bed-sediment samples are designed to prevent 

contamination from metal sources. Non-metallic 

sampling and processing equipment was acid-washed 

and rinsed with deionized water prior to the first sample 

collection. Nylon-mesh sieves were washed in a 

laboratory-grade detergent and rinsed with deionized 

water. All equipment was given a final rinse onsite with 

stream water. Sampling equipment that was reused at 

each site was rinsed between sites with 10-percent 

nitric acid, deionized water, and stream water. Separate 

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

require between-site cleaning.

Quality assurance of analytical results for bed 

sediment included laboratory instrument calibration 

with standard solutions and analysis of quality-control 

samples designed to identify the presence and 

magnitude of bias (E.V. Axtmann, U.S. Geological 

Survey, written commun., 1994). Quality-control 

samples consisted of standard reference materials and 

procedural blanks. Each type of sample was analyzed 

in a proportion equivalent to about 10 to 20 percent of 

the total number of bed-sediment samples.

Standard reference materials (SRMs) are 

commercially prepared materials that have certified 

concentrations of trace elements. Replicate analyses of 

SRMs are used to indicate the reproducibility of 

analytical results and the ability of the method to 

accurately measure a known quantity of a constituent. 

Recovery efficiency of trace-element analyses of 

SRMs for bed sediment is summarized in table 16. 

Two SRMs consisting of agricultural soils representing 

low and high concentrations of trace elements were 

analyzed to test recovery efficiency for a range of 

concentrations generally similar to those occurring in 

the upper Clark Fork basin. The digestion process used 

to analyze bed-sediment samples is not a "total"

10 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

crystalline lattices); therefore, 100-percent recovery 

may not be achieved for elements strongly bound to the 

sediment. The percent recovery of trace elements in 

SRMs when using less than a total digestion is useful to 

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

is consistent between multiple sets of analyses.

Although data-quality objectives have not been 

established for bed sediment, percent recoveries are 

shown in table 16 to illustrate analytical performance. 

Chromium for both low-concentration range (SRM 

2709) and high-concentration range (SRM 2711) 

showed mean recoveries outside a 25-percent deviation 

from complete (100 percent) recovery. Chromium 

recovery was consistently low for both SRM2709 and 

SRM2711 (72.2 and 50.7 percent, respectively). 

Cadmium and silver were below the analytical 

detection limit in the low-range SRM (2709). The 

reason for the lack of measurable recoveries for the low 

range cadmium and silver is believed to be the result of 

analyzing concentrations very close to the detection 

limit, coupled with signal enhancement resulting from 

matrix interference. Mean recoveries for all other 

constituents in both the low and high concentration 

range were within 25 percent. No adjustments were 

made to trace-element concentrations in bed-sediment 

samples on the basis of recovery efficiencies.

Procedural blanks for bed-sediment samples 

consisted of the same reagents used for sample 

digestion and reconstitution. Concentrated nitric acid 

used for sample digestion was heated and evaporated to 

dryness. After evaporation, 0.6 N hydrochloric acid 

was added quantitatively to the dry residue to obtain the 

same dilution ratio as that used in the analysis of bed 

sediment. Procedural blanks, therefore, represent the 

same chemical matrix as the reagents used to digest and 

reconstitute bed-sediment samples. Analytical results 

for procedural blanks can indicate the presence and 

magnitude of potential contamination associated with 

sample handling and analysis in the laboratory 

environment. Results of trace-element analyses of 

procedural blanks for bed sediment are in table 17.

Analytical results of procedural blanks are 

reported as a liquid-phase concentration, in ij,g/mL, 

which is equivalent to parts per million. Determination 

of the significance of a detectable blank concentration 

is based on the magnitude of the equivalent solid-phase 

concentration, in (ig/g, relative to the ambient 

concentration of the trace element in bed-sediment

samples. Because sample weights of individual 

aliquots may vary, the relative significance of blank 

concentrations may differ among samples. If a 

detectable blank concentration, after conversion to a 

solid-phase concentration, represents 10 percent or 

more of the ambient solid-phase concentration, then the 

blank concentration is subtracted to remove potential 

contamination bias. All procedural blanks had 

concentrations less than analytical detection levels. 

None of the detectable concentrations in blanks were 

greater than 10 percent of the ambient concentration; 

therefore, no adjustments were made to trace-element 

concentrations in bed-sediment samples on the basis of 

procedural blanks.

BIOLOGICAL DATA

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

aquatic benthic insects. Insect samples are collected 

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

comparison of annual results.

Methods

Insect samples were collected using protocols 

described in Hornberger and others (1997). Immature 

stages of aquatic benthic insects were collected using a 

large nylon-mesh kick net. A single riffle at each 

station was sampled repeatedly until an adequate 

number of individuals was collected to provide 

sufficient mass for analysis. Targeted taxa for 

collection were Hydropsyche spp., Brachycentrus spp., 

and Arctopsyche grandis of the Order Trichoptera 

(caddisflies), and Claassenia sabulosa of the Order 

Plecoptera (stoneflies). Samples of each taxon were 

sorted by genus and placed in acid-washed plastic 

containers. Samples were frozen on dry ice within 30 

minutes of collection in a small amount of ambient 

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

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

effort to evacuate gut contents. In 1998, a comparison 

of samples collected using both methods showed no 

significant difference in metal concentrations in 

benthic insects, with the exception of copper. Average 

copper concentrations in depurated samples were 8-25 

percent lower than samples frozen within 30 minutes of

BIOLOGICAL DATA H
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).

Insect samples were processed and analyzed at 

the USGS National Research Program laboratory in 

Menlo Park, Calif. Insects were thawed and rinsed 

with ultra-pure deionized water to remove particulate 

matter, then sorted to their lowest possible taxonomic 

level. When large numbers of specimens were collected 

from a station, similar-sized individuals were 

composited into replicate subsamples. Subsamples 

were placed in tared scintillation vials and oven-dried 

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

dry weight and digested by reflux using concentrated 

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

insect samples were evaporated to dryness on a hot 

plate. The dry residue was reconstituted in 0.6 N 

hydrochloric acid, filtered through a 0.45-ujn 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 September 

2000 are summarized in table 18. The variability in the 

number of composite samples among species and 

among sites reflects differences in insect abundance, 

with the number of composite samples increasing with 

the relative abundance of insects. Liquid-phase 

concentrations analyzed in the reconstituted samples 

were converted to solid-phase concentrations using 

equation 4. As with bed sediment, minimum reporting 

levels may differ among sites as a result of variable 

sample weights. In general, the smaller the biological 

sample weight (a function of insect abundance), the 

higher the minimum reporting level. Therefore, higher 

minimum reporting levels do not necessarily imply a 

higher trace-element concentration in tissue.

Two species of Hydropsyche were targeted for 

collection in this study due to their occurrence at most, 

but not all, sites: Hydropsyche occidentalis and 

Hydropsyche cockerelli. Hydropsyche species that 

could not be positively identified were considered to 

belong to the morosa group and are categorized as

Hydropsyche spp. or Hydropsyche morosa group. 

Arctopsyche grandis. Brachycentrus spp.. and 

Claasenia sabulosa also were collected, where 

available, to represent additional insect taxa that are 

fairly widely distributed in the upper Clark Fork basin.

Quality Assurance

The protocols for field collection and processing 

of biota samples are designed to prevent contamination 

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

processing equipment were employed in all sample 

collection. Equipment was acid-washed and rinsed in 

ultra-pure deionized water prior to the first sample 

collection. Nets and equipment were thoroughly rinsed 

in ambient stream water at each new mainstem station. 

New nets were used for the tributary stations. Biota 

samples were collected along an increasing 

concentration gradient to minimize effects from 

potential station-to-station carryover contamination.

Quality assurance of analytical results for biota 

samples included laboratory instrument calibration 

with standard solutions and analyses of quality-control 

samples designed to identify the presence and 

magnitude of bias. Quality-control samples consisted 

of SRM and procedural blanks. Each type of sample 

was analyzed in a proportion equivalent to about 10 to 

20 percent of the total number of biota samples.

Recovery efficiency for trace-element analyses of 

the SRM for biota is summarized in table 19. The 

reference material tested was lobster hepatopancreas. 

Data-quality objectives have not been established for 

analytical recovery in biota, but percent recoveries are 

shown to illustrate analytical performance. Mean 

recoveries were within 6 percent of certified values for 

cadmium, iron, manganese, and zinc. Recoveries for 

copper and nickel were within 12 percent. The high 

bias reported for chromium may be due to an interelement matrix interference within the SRM. Lead 

recoveries could not be measured due to the very low 

solution concentration of lead in the biota standard 

(less than 10 parts per billion). However, a qualitycontrol standard commercially prepared, available 

through the National Institute of Standards and 

Technology, with a similar solution concentration as 

the SRM samples was analyzed throughout the 

analysis. Recoveries for all reported elements were 

within 10 percent of the quality-control standard. No

12 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
adjustments were made to the trace-element concentrations for the insect samples on the basis of recovery 

efficiency.

Results of trace-element analyses of procedural 

blanks for biota are in table 20. Procedural blanks for 

biota consisted of the same reagents used to digest and 

reconstitute tissue of aquatic insects. The blanks were 

analyzed undiluted at a proportion of one blank per site. 

Analytical results for blanks indicated no significant 

contamination bias. With the exception of chromium, 

all concentrations in the blanks were below detection 

levels. The detectable concentrations of chromium are 

within the range of instrument variability and are 

insignificant in relation to the measured concentrations 

in the insect samples; thus, no adjustments were made 

to trace-element concentrations in biota.

STATISTICAL SUMMARIES OF DATA

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

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

The summaries include the period of record, number of 

samples, maximum, minimum, mean, and median of 

concentrations.

Statistical summaries of water-quality data (table 

21) are based on results of cross-sectional samples 

collected periodically by the USGS during the station's 

period of record. They do not include supplemental 

single-vertical samples collected by a contract observer 

at Clark Fork at Turah Bridge near Bonner, Blackfoot 

River near Bonner, and Clark Fork above Missoula 

from 1997 to 1999. Inclusion of supplemental sample 

results targeted for high-flow conditions 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 the annual mean concentrations 

determined from the combined results of composite 

samples for a given year. Therefore, sample sizes for 

bed sediment represent the number of years sampled. 

Sample sizes and statistics for biological data are based 

on individual analyses for each composite sample

collected in individual years rather than the combined 

annual mean concentration. Biota sample sizes 

therefore reflect differences in species abundances at 

each site and among all years. The statistics for biota 

describe the full range of trace-element concentrations 

measured among all available composite samples. The 

abundance of aquatic insects at a particular site in a 

given year limits the biomass of the sample which, in 

turn, may result in different taxa analyzed among years 

or in variable analytical detection limits. Where 

minimum reporting levels vary among years, statistical 

summaries are provided only as a general indication of 

the range of detection.

The presence or absence of insect species at a 

given site can vary among years and may result in 

different taxa being analyzed in the long-term period of 

record. Because Hydropsyche insects were not sorted 

to the species level 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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Effect of tributary inflows on the distribution of 

trace metals in fine-grained sediment and benthic 

insects of the Clark Fork River, Montana: 

Environmental Science and Technology, v. 31, p. 

750-758.

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

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

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STATISTICAL SUMMARIES OF DATA 13
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181 p.

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

sediment analysis: U.S. Geological Survey 

Techniques of Water-Resources Investigations, 

book 5, chap. Cl, 58 p.

Helsel, D.R., and Conn, T.A., 1988, Estimation of 

descriptive statistics for multiply censored water 

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

12, p. 1997-2004.

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

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

of trace metals in surface water, bed sediment, and 

biota of the upper Clark Fork basin, Montana, 

1985-95: U.S. Geological Survey Open-File 

Report 97-669, 84 p.

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

T.L., and Rickert, D.A., 1994, U.S. Geological 

Survey protocol for the collection and processing 

of surface-water samples for the subsequent 

determination of inorganic constituents in filtered 

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

94-539, 57 p.

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

Geological Survey's National Water Quality 

Laboratory: U.S. Geological Survey Open-File 

Report 87-457, 17 p.

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

treatment, and analysis of water samples, Montana 

District: U.S. Geological Survey Open-File 

Report 85-409, 86 p.

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

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

Geological Survey in Montana: U.S. Geological 

Survey Open-File Report 91-216, 41 p.

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

Fork and selected tributaries from Deer Lodge to 

Milltown, Montana, March 1985 through June 

1986: U.S. Geological Survey Open-File Report 

87-110, 48 p.

14 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Lambing, J.H., 1988, Water-quality data (July 1986 

through September 1987) and statistical summaries (March 1985 through September 1987) for 

the Clark Fork and selected tributaries from Deer 

Lodge to Missoula, Montana: U.S. Geological 

Survey Open-File Report 88-308, 55 p.

Lambing, J.H., 1989, Water-quality data (October 1987 

through September 1988) and statistical summaries (March 1985 through September 1988) for 

the Clark Fork and selected tributaries from Galen 

to Missoula, Montana: U.S. Geological Survey 

Open-File Report 89-229, 51 p.

Lambing, J.H., 1990, Water-quality data (October 1988 

through September 1989) and statistical summaries (March 1985 through September 1989) for 

the Clark Fork and selected tributaries from Galen 

to Missoula, Montana: U.S. Geological Survey 

Open-File Report 90-168, 68 p.

Lambing, J.H., 1991, Water-quality and transport 

characteristics of suspended sediment and trace 

elements in streamflow of the upper Clark Fork 

basin from Galen to Missoula, Montana, 1985-90: 

U.S. Geological Survey Water-Resources 

Investigations Report 91-4139. 73 p.

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

assurance for laboratory analysis of suspendedsediment samples by the U.S. Geological Survey 

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

Report 93-131,34 p.

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

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

and biological data (October 1993 through 

September 1994) and statistical summaries of data 

for streams in the upper Clark Fork basin, 

Montana: U.S. Geological Survey Open-File 

Report 95-429, 104 p.

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

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

and biological data (October 1992 through 

September 1993) and statistical summaries of

water-quality data (March 1985 through 

September 1993) for streams in the upper Clark 

Fork basin, Montana: U.S. Geological Survey 

Open-File Report 94-375. 85 p.

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

assessment of the form of trace metals in oxidized 

estuarine sediments employing chemical 

extractants: Science of the Total Environment, 

v. 17, p. 167-196.

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

Techniques of Water-Resources Investigations, 

book 3. chap. C3. 66 p.

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

assurance/quality control manual National Water 

Quality Laboratory: U.S. Geological Survey 

Open-File Report 95-443, 35 p.

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

computation of streamflow: U.S. Geological 

Survey Water-Supply Paper 2175, 2 v., 631 p.

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

measurements: Chelsea, Midi., 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.Al-A9.

REFERENCES CITED 15
DATA

16 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana. October 1999 through September 2000

[Abbreviations: ft3/s, cubic feet per second; °C, degrees Celsius; E, estimated: (ig/L, micrograms per liter; jiS/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 1999

15...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

Streamflow, Specific pH, Temper- Hardness, 

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

taneous onsite (standard water (mg/L as 

(ft3/s) (nS/cm) units) (°C) CaCOj)

1445

1200

1045

0900

0950

1435

0730

0720

6.7

6.4

7.0

7.4

7.2

5.0

3.0

2.4

297 8.0 7.5 120

288 7.8 7.0 110

277 7.9 6.0 110

279 7.8 8.0 110

271 7.9 10.5 100

284 8.2 17.5 110

350 7.6 9.5 140

328 7.7 10.0 130

Calcium, 

dissolved

(mg/L)

33

32

31

31

30

32

40

37

Magnesium, 

dissolved

(mg/L)

8.3

8.1

7.5

7.4

7.1

7.9

9.7

8.9

Arsenic, 

total 

recoverable

(Mg/L)

3

E2

E2

4

4

4

4

E2

Date

NOV 1999

15...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

Arsenic, 

dissolved

(Mg/L)

2

3

2

3

3

4

2

2

Cadmium, 

total 

recoverable

(Mg/L)

<0.1

<.l

<.l

<.l

<.l

<.l

<.l

<.l

Cadmium, ^ . ' Copper,

dissolved . . dissolved 

. ,. . recoverable , ,, ^ (Mg/D ((ig/L) (Mg/L)

<0.1 5 El

<.l 3 2

<.l 3 2

<.l 3 2

<1.0 3 2

<.l 4 2

<1.0 3 2

<1.0 3 2

Iron, 

total 

recoverable

(Mg/L)

603

349

341

344

393

302

139

286

Iron, 

dissolved

(Mg/L)

26

100

120

120

130

67

30

23

Lead, 

total 

recoverable

(Mg/L)

E0.9

<1

<1

<1

<1

<1

<1

<1

Date

NOV 1999

15...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

Lead, 

dissolved

(Mg/L)

<1

<1

<1

<1

<1

<1

<1

<1

Manganese, 

total 

recoverable

(Mg/L)

53

53

36

48

53

33

45

66

Manga- Zinc, Zinc, 

nese, total dissolved 

dissolved recoverable (Mg/L) 

(Mg/L) (ug/L)

33 <31 2

45 5 3

32 3 2

43 5 2

46 4 4

30 2 3

43 6 5

44 6 3

Sediment, 

suspended

(mg/L)

15

6

4

3

5

3

5

3

Sediment 

discharge, 

suspended

(ton/d)

0.27

.10

.08

.06

.10

.04

.04

02

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

70

83

86

90

96

92

96

66

TABLE 4 17
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1999 through September 2000 (Continued) 

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

Date

NOV 1999

15...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

Streamflow, Specific pH, Temper- Hardness, Calcium Magne- Arsenic, 

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

lme taneous onsite (standard water (mg/L as ,. . dissolved recoverable

(ft-'/s) (nS/cm) units) <"C) CaCO3) ' S ' (mg/L) (ug/L)

1530 21 522 7.9 7.0 170 47 12 13

1315 23 525 7.9 9.0 170 47 12 11

1210 24 493 7.9 10.0 160 46 11 10

1000 22 470 7.6 K.5 15(1 42 10 9

1105 21 481 7.7 12.5 160 45 11 8

1545 16 506 8.1 20.0 170 47 12 10

0830 14 546 7.5 13.5 160 46 12 10

0815 13 562 7.5 15.0 170 48 12 7

Date

NOV 1999

15..

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04..

JUL

21...

SEP

01...

Cadmium, . . Copper, ., Iron, . Lead, Arsenic, . . Cadmium, , . Copper, . . , Iron, ... total total . total .. , . total dissolved . dissolved . . dissolved .. dissolved . . 

, recoverable , ,. recoverable ,. , recoverable , ,, recoverable

(Ug/L) * ' (ng/L) (ug/L) (ug/L)

81 .2 82 7 1,180 24 36

11 2 1 76 20 843 31 14

7 2 .7 54 16 834 31 15

7 1 .8 30 14 426 47 3

71 <1 26 39 322 23 2

9 .9 .7 27 16 244 18 2

71 1 31 13 107 21 1

7 .7 .8 16 9 92 20 1

Date

NOV 1999

15...

MAR 2000

06..

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

Manila- ,. . . ,, .. . Sediment, 6 Manga- Zinc, Zinc, ,, .. . Sediment . ' Lead, nese, B ' .. . ' Sediment, suspended 

.... ... nese, total dissolved . ' discharge, . r . dissolved total .. , ' ,,. suspended J". (percent 

, , , . dissolved recoverable (ug/L) . ,. , suspended _ r .. 

recoverable ^ ^ (mg/L, ^ ££ 

<1 428 305 285 118 19 1.1 86

<1 595 534 426 318 20 1.2 71

<1 510 487 319 237 18 1.2 84

<1 352 348 257 241 9 .53 92

<1 269 252 254 248 6 .34 85

El 268 246 178 155 4 .17 89

<1 208 189 292 266 4 .16 85

<1 176 161 234 217 4 .14 81

IS Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1999 through September 2000 (Continued)

12323600-SILVER BOW CREEK AT OPPORTUNITY, MONT.

Date

NOV 1999

16...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

Streamflow,

Time instantaneous

(ft-'/s)

0745 35

1415 36

1310 39

1115 45

1210 45

1650 25

0920 15

1005 16

Specific pH, Temper- Hardness, ~ . Magne- Arsenic,

conductance, onsite ature, total j.30'," I sium, total f i, dissolved . . . onsite (standard water (mg/L as (11) dissolved recoverable

(|iS/cm) units) (°C) CaCO3) (ms ' (mg/L) ((ig/L)

491 8.2 2.0 170 51 11 17

497 8.8 6.5 170 50 11 18

464 8.9 10.5 170 49 11 18

464 8.6 8.5 160 47 10 16

392 9.0 14.0 150 44 9.0 13

403 9.5 22.5 150 45 9.3 16

599 8.6 14.5 210 62 14 22

616 8.5 13.0 210 62 13 23

Date

NOV 1999

16..

MAR 2000

06...

APR

04...

MAY

09...

22..

JUN

04...

JUL

21...

SEP

01...

Arsenic, Cadmium. 

. . total dissolved . . 

. , recoverable

< ^8/L> U*/L)

11 1

17 2

12 <1

10 1

9 .7

13 .6

16 .7

19 .9

 . . Copper, ., Iron, , Lead, Cadmium, "T. Copper, . ' Iron, » . , 

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

^g/L) referable dl(^d recoverable d'(S^d recoverable

1 87 31 484 E9 17

.8 129 43 804 15 19

.6 109 32 803 11 19

.5 84 24 667 <10 15

.3 62 19 537 E7 12

.2 62 34 385 13 8

.3 65 26 276 14 7

A 79 30 305 E9 7

Date

NOV 1999

16..

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

MangaLead, nese. 

dissolved total 

(Hg/L) recoverable

(Ug/L)

<1 467

<1 623

<l 488

E.5 471

<1 277

<1 174

<1 253

<1 460

Manga- Zinc, Zinc, ,. . Sediment Sediment 

. .. . . Sediment, .. . suspended 

nese total dissolved suspended d,scharge ( 

dissolved recoverable ([xg/L) m suspended ^

(^g/L) (ug/L) (ton/d) 0.062mm)

416 469 352 11 1.0 78

546 359 153 15 1.5 88

421 301 96 17 1.8 85

386 324 147 17 2.1 88

180 190 56 14 1.7 85

68 144 27 10 .68 87

188 169 71 7 2& 85

350 251 109 9 .39 81

TABLE 4 19
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1999 through September 2000 (Continued)

12323750-SILVER BOW CREEK AT WARM SPRINGS, MONT.

Date

NOV 1999

16...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

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

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

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

(ft3/s) (nS/cm) units) (UC) CaCO3) (mg/L' (mg/L)

0930 40 601 8.4 5.0 240 69 17

1515 50 587 8.7 6.0 240 70 16

1345 53 603 8.5 10.0 240 71 16

1210 60 547 8.7 11.0 220 62 16

1300 87 395 9.0 15.5 150 43 II

1740 79 399 9.2 19.0 150 42 12

1040 29 588 9.2 17.5 260 75 18

1150 16 682 8.6 13.5 290 85 18

Arsenic, 

total 

recoverable

(Hg/L)

12

13

12

18

25

28

33

24

Date

NOV 1999

16...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

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

dissolved t, dissolved .., dissolved ui dissolved 

. . recoverable ,. recoverable recoverable , ,. , (ug/L) , ,. ^ (l^g/L) . . (t^g/L) , ,. . (Hg/L) (Hg/L) vre (ng/L) vre (|ig/L) vre

10 <.l <.l 5 3 152 E7

10 .1 <.l 8 6 222 E9

10 .1 <.l 10 9 262 E5

16 <.l <.l 7 4 233 17

20 E.09 <.l 9 5 297 17

25 <.l <.l 9 5 270 31

26 <.l <.l 7 3 88 <10

22 <.l <.l 6 3 72 <10

Lead, 

total 

recoverable

(Hg/L)

E.8

<1

2

1

1

1

<1

<1

Date

NOV 1999

16...

MAR 2000

06..

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

Manga- _. . . c .. , 

, Manga- £inc, Ainc, ~ .. Nediment Lead. nese, ^ , Sediment, .. 

nese, total dissolved . . discharge, dissolved total .. . . . . . suspended Jr .

(ug/L) recoverable / ^^s ' (mg/L) 

t it \ (WS'L) (^g'L) (ton/d)

<1 151 136 <3l 10 1 .11

<1 180 133 30 13 4 .54

<1 216 159 26 12 6 .86

<1 299 252 15 7 3 .49

<1 228 111 16 4 7 1.6

<1 240 105 10 6 4 .85

<1 79 28 7 2 5 .39

<1 89 47 7 2 4 17

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

90

88

69

93

92

95

67

75

20 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana. October 1QQQ through September 2000 (Continued)

12323770 -WARM SPRINGS CREEK AT WARM SPRINGS, MONT.

Date

NOV 1999

16...

APR 2000

04...

MAY

22...

JUN

04...

JUL

21...

SEP

01...

Time

0815

1430

1345

1820

1015

1040

Streamflow, 

instantaneous 

<tt3/s)

48

47

48

43

4.8

18

Specific 

conductance, 

onsite

(MS/cm)

352

362

253

259

539

373

pH, 

onsite 

(standard 

units)

8.2

8.5

8.5

8.4

8.3

8.3

Temperature, 

water

(°C)

3.5

11.5

15.0

18.0

16.0

12.0

Hardness, 

total 

(mg/L as 

CaC03)

170

170

120

120

270

180

Calcium, 

dissolved

(mg/L)

51

53

36

36

83

54

Magnesium, 

dissolved

(mg/L)

10

11

6.7

6.8

15

9.7

Arsenic, 

total 

recoverable

(Mg/L)

6

4

5

5

12

7

Date

NOV 1QW

16...

APR 2000

04...

MAY

22...

JUN

04...

JUL

21...

SEP

01...

Arsenic, 

dissolved 

(Mg/L)

4

4

4

5

9

7

Cadmium, 

total 

recoverable

.2

<.l

<.l

<.l

<.l

<.l

Cadmium, 

dissolved

(Mg/L)

<.l

<J

<.l

<.l

<.l

<.l

Copper, 

total 

recoverable

26

7

12

12

8

7

Copper, 

dissolved

(Mg/L)

El

2

3

3

4

4

Iron, 

total 

recoverable

375

75

167

140

44

53

Iron, 

dissolved

13

<10

13

<10

Efi

E9

Lead, 

total 

recoverable

(Mg/L)

2

<1

1

1

<1

«

Lead, 

Date dissolved

(Mg/L)

NOV 1999

16... <1

APR 2000

04.., <1

MAY

22.- <1

JUN

04... <1

JUL

21... <1

SEP

01... <1

Mangatotal 

recoverable

302

204

216

208

80

136

Manganese, 

dissolved

257

187

131

123

61

96

Zinc, 

total 

recoverable

<31

3

6

3

2

3

Zinc, 

dissolved

(Mg/L)

1

5

3

3

2

2

Sediment, 

suspended

(mg/L)

18

5

10

7

4

3

Sediment 

discharge, 

suspended 

(ton/d)

2.3

.63

1.3

.81

.05

.15

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

82

69

72

71

83

69

TABLE 4 21
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1999 through September 2000 (Continued)

12323800-CLARK FORK NEAR GALEN, MONT.

Date

NOV 1999

16...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

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

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

lme taneous onsite (standard water (mg/L as fSS°n\ dissolved recoverable

(ft3/s) (MS/cm) units) <°C) CaCO3) (mg ' (mg/L) (Mg/L)

1015 89 483 8.5 4.5 210 60 14 8

1610 100 489 8.5 6.0 210 61 13 9

1515 106 502 8.5 10.5 220 66 14 8

1250 89 481 8.4 10.5 200 57 13 12

1420 122 356 8.8 15.5 150 44 10 18

1850 120 352 8.9 19.0 140 41 9.9 20

1130 25 598 8.7 18.5 260 74 17 29

1220 32 534 8.4 14.0 240 70 15 15

Date

NOV 1999

16...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

Arsenic, Cadmium, Cadmiuin, Copper, Iron Iron Lead

dissolved t0ta' dissolved tota' dissolved *** . , dissolved total . , 

,. . recoverable , ._ . recoverable , recoverable . ,. recoverable (Mg/L) , ,, , 'Mg/L) , ,, * (Mg/L) , ,, * (Mg/L) , i¥ x (M8/L) (Mg/L) (Mg/L) (Mg/L)

7 E.05 <.l 8 3 137 <10 El

7 E.06 <.l 7 4 141 E7 <1

7 <.l <.l 9 4 156 <10 1

11 <.l <.l 9 3 175 19 1

15 E.05 <.l 14 5 278 10 2

19 <.l <.l 13 5 230 18 1

23 <.l <.l 10 6 82 <10 <1

13 E.06 <.l 9 5 79 E7 <1

Date

NOV 1999

16...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

04...

JUL

21...

SEP

01...

. . Manga- Manga- Zinc, Zinc. .. , Sediment ****""*£. Lead, nese, K . . . .. . . Sediment, .. . suspended 

.... ^ nese, total dissolved . . discharge, , dissolved total .. . ' . . , suspended J5 ! (percent 

,. , . . dissolved recoverable (Mg/L) , ,. , suspended ,. ... (Mg/H recoverable ,,^ », Ke ' (mg/L) (t n/d) flnerthan 

((-ig/L) 0.062 mm)

<1 163 129 <31 6 2 .48 81

<1 177 137 18 9 4 1.1 76

<1 155 121 13 6 5 1.4 60

<1 220 159 12 6 4 .96 75

<1 230 81 16 4 10 3.3 75

<1 210 68 10 4 6 1.9 86

<1 114 65 8 4 3 .20 78

<1 98 46 11 4 5 .43 80

22 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin. Montana. October 1999 through September 2000 (Continued)

12324200-CLARK FORK AT DEER LODGE, MONT.

Date

NOV 1999

16...

MAR 2000

06...

APR

04...

MAY

09..,

22.,

JUN

05...

JUL

21...

SEP

05...

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

._. instan- conductance, onsite ature, total a 1 sium, Time .^ , . . ^ ,. dissolved .. . . 

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

(ft3/s) (nS/cm) units) (°C) CaCO3) <mg'M (mg/L)

1200 209 520 8.4 4.0 230 66 15

1715 225 506 8.4 8.0 230 66 15

1610 209 535 8.4 12.0 240 72 16

1350 108 523 8.5 11.5 220 64 15

1530 97 451 8.7 17.5 190 57 12

0720 116 463 8.1 14.0 200 58 13

1225 29 512 8.6 19.5 220 65 14

1115 86 564 8.3 13.5 250 75 16

Arsenic, 

total 

recoverable

(Mg/L)

9

10

10

12

16

19

15

15

Date

NOV 1999

16...

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

05...

JUL

21...

SEP

05...

Arsenic, Cadmium, CadmiuIT1) Copper, Iron ,ron

dissolved tota' , dissolved tota' , dissolved tota' , dissolved 

, recoverable , . recoverable , recoverable , 

(Mg/D ((WL) (Mg/L) (|lg/L) (Mg/D fog/L) (Mg/L)

8 <.l <.l 19 4 232 <10

8 <.l <.l 17 5 269 <10

9 <.l <1 20 6 262 <10

11 <.l <.l 16 7 146 16

14 <.l <.l 18 8 134 10

17 .1 <.l 29 7 335 E7

12 <.l <.l 13 6 98 <10

12 .2 <.l 38 5 494 <10

Lead, 

total 

recoverable

2

2

2

2

1

3

1

5

Date

NOV 1999

16. .

MAR 2000

06...

APR

04...

MAY

09...

22...

JUN

05...

JUL

21...

SEP

05...

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

ri Lead' f; nese, total dissolved Sediment discharge, 

dissolved total .. . ' . . . . suspended . . 

,. . . dissolved recoverable (Mg/L) , ,, . suspended (Mg/L) recoverable , . , n (mg/L) ' ...

(ng/L) ((IS/L) ((Ig/L) (t0n/d)

<1 70 27 E15 7 10 5.6

<1 62 30 23 10 13 7.9

<1 60 31 20 7 13 7.3

<1 119 113 21 10 4 1.2

<1 70 42 15 5 7 1.8

<1 157 64 28 12 15 4.7

<1 85 47 11 4 21 1.6

<1 185 29 45 5 31 7.2

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

80

70

72

88

84

92

69

84

TABLE 4 23
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1999 through September 2000 (Continued)

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON, MONT.

Date

NOV 1999

16...

APR 2000

04...

MAY

24...

JUN

06...

JUL

27...

SEP

05...

Streamflow, Specific pH, Temper- Hardness, 

 . instan- conductance, onsite ature, total j.30 ," j Time ^ . ^ . . ^ . ,, dissolved taneous onsite (standard water (mg/L as ,. .

(ft3/s) (MS/cm) units) (°C) CaCO3) 8

1245 55 281 8.4 4.0 130 38

1715 88 293 8.5 11.0 130 37

0835 78 281 8.1 10.0 130 39

0800 88 286 8.2 11.5 130 38

1145 27 309 8.4 18.5 150 44

1230 15 338 8.5 15.5 160 47

Magnesium, 

dissolved

(mg/Ll

8.8

8.3

8.8

8.8

10

10

Arsenic, 

total 

recoverable

(Hg/Lj

4

5

5

5

6

5

Date

NOV 1999

16...

APR 2000

04...

MAY

24...

JUN

06...

JUL

27...

SEP

05...

. . Cadmium, _ . . Copper, Iron, Arsenic, . Cadmium, "T Copper, ' 

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

,. . recoverable ,, . recoverable ,, . recoverable

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

4 <.1 <.l E1 E.8 36

5 <.l <.l 2 E1 158

5 <.1 <.1 2 E1 126

6 <.1 <.1 3 E1 124

5 <.1 <.! 1 <1 57

5 <.l <-1 1 El 63

Iron, 

dissolved

(Hg/L)

<10

E7

13

18

E9

E6

Lead, 

total 

recoverable

(Mg/L)

<1

<1

<1

<1

<1

<1

Date

NOV 1999

16...

APR 2000

04...

MAY

24...

JUN

06...

JUL

27...

SEP

05...

Manea- _. . . 

. , Manga- Zinc, Zinc, ,. Lead, nese, e ' . ' Sediment, 

.... ' nese, total dissolved . ' dissolved total . . . , ,. . suspended 

(Mg/L) recoverable "f recoverable (W/L) ^ 

(Mg/L) (|ig/L) (^'L)

<1 6 4 <31 <1 2

<1 18 7248

<1 27 17 5 2 7

<1 25 15 <1 <1 6

<1 22 13 <1 <1 3

<1 21 11 1 <1 16

Sediment 

discharge, 

suspended

(ton/d)

.30

1.9

1.5

1.4

.22

.65

Sediment, 

suspended 

(percent finer 

than 0.062 mm 1

88

84

84

84

88

32

24 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin. Montana. October 1999 through September 2000 (Continued)

12324680-CLARK FORK AT GOLDCREEK, MONT

Date

NOV 1999

17...

MAR 2000

07...

APR

05...

MAY

09...

22...

JUN

05...

JUL

21...

SEP

05...

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

_,. instan- conductance, onsite ature, total .. ,U .' sium, Time . . , * j j i, dissolved .. , ' taneous onsite (standard water (mg/L as ,. . dissolved

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

0920 345 467 8.3 3.0 200 59 13

0810 385 446 8.2 4.5 200 59 13

0810 395 468 8.3 6.5 200 59 13

1520 260 402 8.6 12.0 170 49 11

1655 248 393 8.8 17.5 170 50 11

0845 260 408 8.3 14.5 180 51 12

1330 93 431 8.7 21.5 190 56 13

1320 102 510 8.6 17.0 230 67 15

Arsenic, 

total 

recoverable

(Mg/L)

8

10

11

9

11

11

12

12

Date

NOV 1999

17...

MAR 2000

07...

APR

05...

MAY

09...

22...

JUN

05...

JUL

21...

SEP

05...

. . Cadmium, , . . Copper, Iron, . Arsenic, . , Cadmium, . V, Copper, . ' Iron, 

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

,. recoverable ,. . recoverable , ,, , recoverable . ...

^g/L> (Mg/L) (lig/L) (Mg/L) (W!/L) (Mg/L) <(ig/L)

7 .1 <.l 21 3 280 <IO

7 .2 <] 25 5 440 10

8 .2 <.l 33 4 420 E10

8 <.I <1 9 4 129 <IO

9 <.l <.l 11 5 166 <10

11 E.05 <.l 16 5 250 <IO

10 <.l <.l 9 4 113 <10

12 <.l <.l 11 4 150 <10

Lead, 

total 

recoverable

(Mg/L)

3

3

5

<1

1

2

<1

1

Date

NOV 1999

17...

MAR 2000

07...

APR

05...

MAY

09...

22...

JUN

05.-

JUL

21...

SEP

05...

. . Manga- Zinc, Zinc, ~ .. Sediment 

Lead nese ^ ^^ Sediment discharge,

dissolved total .. . ' ., , . suspended . . 

, ,, . , , dissolved recoverable (Mfi/L) , ,_ . suspended (Mg/L) recoverable , ,. . . ,. (mg/L) , .

(Mg/L)

<1 80 14 E27 5 15 14

<I 81 25 32 9 23 24

<1 66 25 38 5 41 44

<1 41 20 9 3 6 4.2

<1 56 15 14 4 9 6.0

<1 87 20 15 5 13 9.1

<1 66 15 8 3 7 1.8

<1 60 7 12 2 12 3.3

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

84

75

75

85

91

93

86

78

TABLE 4 25
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1999 through September 2000 (Continued)

12331500-FLINT CREEK NEAR DRUMMOND, MONT.

Date

NOV 1999

17...

MAR 2000

07...

APR

04...

MAY

09...

22...

JUN

05...

JUL

27...

SEP

05...

Streamflow, Specific pH, Temper- Hardness, . . Magnerp. instan- conductance, onsite ature, total .. . ! sium, 

lme taneous onsite (standard water (mg/L as ' ,. dissolved 

(ft3/s) (nS/cm) units) (°C) CaCO3) (mg/L» (mg/L)

1030 El 18 328 8.3 3.0 150 40 12

0920 104 317 8.3 3.5 150 39 12

1820 101 318 8.8 12.0 150 40 12

1625 2.8 406 8.8 13.0 180 49 14

1800 16 275 8.7 18.5 130 36 10

0945 21 417 8.4 12.5 190 53 15

1030 8.0 512 8.3 16.0 250 68 19

1415 26 529 8.4 16.5 230 65 17

Arsenic, 

total 

recoverable

i^g/L)

7

9

10

11

12

11

13

13

Date

NOV 1999

17...

MAR 2000

07...

APR

04...

MAY

09...

22...

JUN

05...

JUL

27...

SEP

05...

. . Cadmium, , _. . Copper, , Iron, _ Arsenic, Cadmium, " Copper, . Iron,

dissolved ,., dissolved ,., dissolved ,., dissolved 

,. , recoverable , ,, . recoverable , ,. ^ recoverable , ...

<tig/L) (ng/L) <W!/L) (Mg/L) <1Jg/L) (Mg/L) <lig/L)

5 <.l <.l 2 E.7 126 E6

6 <.l <.l 2 E.7 232 E9

8 <.l <.l 2 E.8 250 <10

11 <.l <.l 2 El 69 <10

10 <.l <.l 2 2 210 E6

12 <.l <.l 3 1 86 13

11 <.l <.l 2 El 72 E9

12 1 <.l 2 2 166 17

Lead, 

total 

recoverable

2

3

3

<1

3

1

<1

2

Date

NOV 1999

17...

MAR 2000

07...

APR

04...

MAY

09...

22...

JUN

05...

JUL

27...

SEP

05...

. . "*^ Manga- Zinc, Zinc, .. . Sediment Lead, nese, " , .. Sediment, .. . 

.... . nese, total dissolved , , discharge, dissolved total .. . ' .. . ,' suspended .B J 

,. . . . dissolved recoverable (Mg/L) , ,, . suspended

CTO/L) reC(°^b'e (tig/D (HK/L) <mg/L) (ton/d)

<1 52 17 <3l 1 7 E2.2

<1 66 20 13 3 12 3.4

<1 81 22 9 3 17 4.6

E.6 51 38 7 3 3 .02

<1 118 40 10 3 13 .56

<1 100 78 3 4 4 .23

<1 110 90 4 1 13 .28

<1 132 63 7 3 19 1.3

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

76

85

78

79

92

89

70

55

26 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1999 through September 2000 (Continued)

12331800-CLARK FORK NEAR DRUMMOND, MONT.

Date

NOV 1999

17...

MAR 2000

07...

APR

05...

MAY

09...

23...

JUN

05...

JUL

21...

SEP

05...

Time

1120

1030

0915

1730

0825

1045

1440

1515

Streamflow, Specific pH, Temperinstan- conductance, onsite ature, 

taneous onsite (standard water 

(ft-'/s) (nS/cm) units) (°C)

556 474 8.3 4.5

570 464 8.4 6.5

529 483 8.4 8.5

315 485 8.5 14.0

253 513 8.2 14.5

337 508 8.4 17.5

181 573 8.5 22.5

194 616 8.5 17.5

Hardness, Ca Magnetot,al dissolved J""?1 ' (mg/L as ,, , dissolved

CaC03) (mg/L) (mg/L)

210 60 15

220 62 15

220 62 15

220 63 15

240 68 17

230 65 16

270 76 19

280 80 19

Arsenic, 

total 

recoverable

8

10

10

9

10

12

13

11

Date

NOV 1999 

17...

MAR 2000

07...

APR

05...

MAY

09...

23...

JUN

05...

JUL

21...

SEP

05...

Arsenic, 

dissolved

(Hg/L)

7

7

9

9

10

12

10

11

Cadmium. Cadmium, Copper, 

total ' total 

recoverable , S°^ recoverable

E.08 <.l 11

E.1 <.l 28

<.l <.l 13

<.l <.l 8

<.l <.l 7

<.l <.l 10

<.l <.l 8

E.08 <.l 8

 Iron, _ Copper, . . , Iron, j- , . total .. , . dissolved . , dissolved 

,. recoverable . (l^g/L) ,, (l^g/L)

3 184 <10

5 366 <10

4 278 <IO

4 80 <IO

5 53 E6

5 108 <10

4 93 <10

8 91 <10

Lead, 

total 

recoverable

2

3

2

1

<1

<1

<1

<1

Date

NOV 1999

17...

MAR 2000

07...

APR

05...

MAY

09...

23...

JUN

05...

JUL

21...

SEP

05...

Lead, 

dissolved

(Hg/L)

<1

<l

E.5

<1

<]

<1

<]

<1

Manga- Manga- Zinc,

nese, 

. . . nese, total i total .. , . _ , 

, , dissolved recoverable recoverable ,, , ,, ,

/¥ ((^S'L'' (l^S' LJ ^|Ag/L)

56 10 <31

63 19 27

59 19 18

27 13 14

32 19 11

46 15 9

57 13 10

36 7 II

r, Zin,C' Sediment, ^^ dissolved . \ discharge, 

, , suspended ° I

(ug/L) , ,, -. suspended

(mg/L) (ton/d)

4 12 18

8 20 31

7 21 30

4 4 3.4

8 3 2.0

6 6 5.5

3 23 11

4 25 13

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

73

74

67

91

92

82

50

44

TABLE 4 27
Table 4. Water-quality data for the upper Clark Fork basin, Montana. October 1999 through September 2000 (Continued)

12334510--ROCK CREEK NEAR CLINTON, MONT.

Date

NOV 1999

17...

APR 2000

05...

MAY

23...

JUN

05...

JUL

27...

SEP

06...

Time

1230

1030

1010

1210

0745

1050

Streamflow, Specific pH, Temper- Hardness, 

instan- conductance, onsite ature, total a ,CI.UI ,' 

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

(ft3/s) (nS/cm) units) (°C) CaCO3) ( g'L)

201 149 8.2 3.5 67 17

266 138 8.0 6.0 62 16

932 83 8.0 10.5 36 9.3

715 98 8.1 12.5 43 11

201 146 8.1 15.0 68 18

183 158 8.2 10.5 71 18

Magnesium, 

dissolved

(mg/L)

5.9

5.4

3.1

3.7

5.9

6.1

Arsenic, 

total 

recoverable

(Mg/L)

<3

<3

<3

<3

E2

<3

Date

NOV 1999

17...

APR 2000

05...

MAY

23...

JUN

05...

JUL

27...

SEP

06...

Arsenic, 

dissolved

<2

E.6

E.5

E.6

E.7

E.6

Cadmium, _ . . Copper. Iron, 

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

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

(Mg/L) re (Mg/L) ^ (Mg/L)

<.l <.l <1 <1 21

<.l <.l <1 <1 63

<.l <.l 1 E.9 211

<.l <.l 2 <1 91

<.l <.l <1 <1 67

<.l <.l <1 E.7 51

Iron, 

dissolved

E6

11

20

<10

E10

15

Lead, 

total 

recoverable

(Hg/L)

<1

<1

<1

<1

<1

<1

Date

NOV 1999 

17...

APR 2000

05...

MAY

23...

JUN

05...

JUL

27...

SEP

06...

Lead, 

dissolved 

(Mg/L)

<,

<1

<1

<1

<1

<1

Manga- Manga- Zinc, Zinc, 

"7; nese, total dissolved ^diment 

t0ta' , dissolved recoverable (Mg/L) suspended 

recoverable ,, ,. ^B (mg/L) 

(Hg/L) ^ (tig

E2 <1 <31 <1 1

3 <1 <1 <1 4

13 133 16

6 1 <1 26

8 3 2 <1 5

6 2 <1 <1 3

Sediment 

discharge, 

suspended 

(ton/d)

.54

2.9

40

12

2.7

1.5

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

50

77

70

73

71

76

28 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin. Montana. October 1999 through September 2000 (Continued)

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

Date

NOV 1999

17...

MAR 2000

07...

APR

05...

MAY

10...

23...

JUN

05...

JUL

21...

SEP

05...

Time

1345

1220

1210

1040

1155

1325

1550

1645

Streamflow, Specific pH, Temper- Hardness, 

instan- conductance, onsite ature, total . ' 

taneous onsite (standard water (mg/L as J °/i\ 

(ft3/s) (nS/cm) units) ("C) CaCO3) lmg'M

831 390 8.6 5.0 180 49

963 369 8.5 6.0 170 47

907 365 8.5 7.5 160 45

1,080 234 8.4 9.0 100 29

1,230 201 8.3 12.5 88 24

1,100 245 8.5 16.0 110 29

452 310 8.8 21.5 140 39

342 359 8.7 15.0 160 44

Magnesium, 

dissolved

(mg/L)

13

12

12

7.6

6.6

8.0

11

12

Arsenic, 

total 

recoverable

(Mg/L)

6

7

5

3

3

4

6

5

Date

NOV 1999

17...

MAR 2000

07...

APR

05...

MAY

10...

23...

JUN

05...

JUL

21...

SEP

05...

Arsenic, 

dissolved

(Mg/L)

6

5

5

3

3

4

5

5

Cadmium, . . Copper, Iron, 

... Cadmium, A rK, ' Copper, . ' total .. , ' total .. . j total 

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

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

<.l <.1 7 2 101

<.l <.1 12 3 252

<.l <.l 8 2 212

<.l <.l 4 2 104

<.l <.1 5 2 211

<.l <.l 6 2 131

<.l <.l 5 2 85

<.l '32 50

Iron, 

dissolved

(Mg/L)

<10

<10

<10

<10

12

<10

<10

E7

Lead, 

total 

recoverable

(Mg/L)

El

2

1

<]

<1

<1

<1

<1

Date

NOV 1999

17...

MAR 2000

07...

APR

05...

MAY

10...

23...

JUN

05...

JUL

21...

SEP

05...

Lead, 

dissolved

(Mg/L)

<1

<1

<1

<1

<1

<1

<1

<1

MnTsf M»"*>- ?- ,Zi7' Sediment, 

. . nese. total dissolved . . total .. . * . . , ,. . suspended 

. . dissolved recoverable (us, LA . ,. .

TM'/L) (^g/L) ( IL)

28 3 <31 3 5

43 9 30 6 14

37 7 14 4 14

14 4 6 3 5

21 4 11 4 14

27 4 7 4 9

25 5 8 2 9

13 3 6 1 5

Sediment 

discharge, 

suspended 

(ton/d)

11

36

34

15

46

27

11

46

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

89

84

81

78

74

79

82

89

TABLE 4 29
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1999 through September 2000 (Continued)

12340000-BLACKFOOT RIVER NEAR BONNER, MONT.

Date

NOV 1999

18...

APR 2000

05...

MAY

23...

JUN

05...

JUL

21...

SEP

06...

Time

0940

1440

1415

1455

1720

0930

Streamflow, Specific pH, Temper- Hardness, . .

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

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

(ft3/s) (uS/on) units) (°C) CaCO3) UnK/LJ

621 273 8.3 4.0 130 34

1330 213 8.6 9.0 100 27

4210 157 8.4 12.0 78 20

3100 175 8.4 14.5 86 22

816 237 8.7 21.0 120 30

541 275 8.5 12.5 130 33

Magnesium, 

dissolved

(mg/L)

12

9.0

6.7

7.5

11

12

Arsenic, 

total 

recoverable

<3

<3

<3

<3

E2

<3

Date

NOV 19W

18...

APR 2000

05...

MAY

23...

JUN

05...

JUL

21...

SEP

06...

Arsenic, 

dissolved

El

1

E.7

E.8

1

1

Cadmium. _ . . Copper. Iron, 

. Cadmium, 1 , Copper, . ' total total *T ' total 

recoverable disso^ed recoverable dissolved recoverable

(ng/L) " ([^g/L) (Mg/L)

<.l <.l <l <1 26

<.l <.l 3 E.8 235

<.l <.l 2 2 214

<.l <.l 2 <1 110

<.l <.] <1 <1 24

<.l <.l <1 <1 26

Iron, 

dissolved

(Hg/L)

<10

38

E9

<10

E7

<10

Lead, 

total 

recoverable

<1

<1

<1

<1

<1

<1

Date

NOV 1999

18...

APR 2000

05...

MAY

23...

JUN

05...

JUL

21...

SEP

06...

Lead, 

dissolved

(HS/L)

<1

<1

<1

<1

<1

<1

Manga- Manga- Zinc, Zinc, . 

"7e.' not total dissolved Sediment 

total .- , . . . / i, . suspended 

recoverable d'(s^ d wfi* ^ ' (mg/L)

E2 1 <31 <1 2

20 3 1 3 12

19 2 4 2 18

12 2 <1 3 9

6 2111

5 <1 1 <1 2

Sediment 

discharge, 

suspended 

(ton/d)

3.4

43

205

75

2.2

2.9

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

96

86

81

84

90

92

30 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in tbe 

upper Clark Fork basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1999 through September 2000 (Continued)

12340500-CLARK FORK ABOVE MISSOULA, MONT.

Date

NOV 1999

18...

MAR 2000

07...

APR

05...

MAY

10...

23...

JUN

05...

JUL

21...

SEP

06...

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

. .' H . , Calcium. 

 . install- conduct- onsite ature, total .. . ' Time . . . . ,. dissolved taneuus ance, onsite (standard water (mg/L as ,.

(«3/s) (nS/cm) units) (°C) CaCOj) (nlg/L'

1100 1,490 340 8.5 4.5 160 42

1500 1,600 317 8.4 6.5 150 41

1635 2,300 279 8.4 7.5 130 36

0X30 4,860 183 8.3 8.5 86 23

1545 5,450 169 8.3 12.0 79 21

1630 4,220 197 8.3 14.5 91 24

1830 1.230 267 8.4 20.0 120 32

0755 854 307 8.4 13.5 140 37

Magnesium, 

dissolved 

(mg/L)

12

11

11

7.1

6.6

7.7

11

12

Arsenic, 

total 

recoverable

(Hg/L)

3

4

3

El

E2

E2

3

3

Date

NOV 1999

18...

MAR 2000

07...

APR

05...

MAY

10...

23...

JUN

05...

JUL

21...

SEP

06...

Arsenic, Cadmium, Cadnliunl; Copper, Iron 

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

, , recoverable . , recoverable . . recoverable (|J.g/L) . , (Hg/L) . /. - (ng'L) . ,. ,

4 <.l <.l 6 1 79

4 <.l <.l 7 3 166

3 <.l <.l 5 2 182

1 <.l <.l 5 El 175

1 <.l <.l 4 2 169

2 <.l <.l 6 2 98

2 <.l <.l 2 E.7 80

3 <.l <.l 3 2 56

Iron, 

dissolved

(Hg/L)

<10

13

19

11

15

<10

E6

<10

Lead, 

total 

recoverable

(p.g/L)

<1

<1

<1

<1

<1

<1

<1

<1

Date

NOV 1999

18...

MAR 2000

07...

APR

05...

MAY

10...

23...

JUN

05...

JUL

21...

SEP

06...

, . Ma"ga' Manga- Zinc, Zinc, . .. , Lead, nese, . ^ , j. , j Sediment, 

.... , nese, total dissolved . . dissolved total .. . ' . . . > suspended 

, _ > . . dissolved recoverable (UB'L) , a <. (Hg/L) recoverable (^g/L) ([ig/L) (mg/L)

<1 23 14 <31 2 4

<1 38 26 12 4 9

<1 27 19 8 2 9

<1 20 9 8 3 12

<1 20 8 6 3 15

<1 18 10 2 3 6

<1 26 14 3 3 6

<1 15 6 4 1 4

Sediment 

discharge, 

suspended 

rton/d)

16

39

56

157

221

68

20

9.2

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

93

93

97

93

89

91

88

92

TABLE 4 31
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1999 through 

September 2000

[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)

163

160

157

164

181

181

183

192

202

204

204

203

197

199

205

212

213

222

215

208

207

212

213

208

I9X

196

217

235

240

244

240

6,275

202

244

157

Suspended sediment

Mean 

concentration

(mg/L)

October

11

10

10

9

8

9

13

22

20

19

18

17

16

15

14

13

12

11

II

10

10

10

10

10

10

10

16

21

20

17

14

...

13

22

8

Discharge 

(ton/d)

4.8

4.3

4.2

4.0

3.9

4.4

6.4

II

11

10

9.9

9.3

8.5

8.1

7.7

7.4

6.9

6.6

6.4

5.6

5.6

5.7

5.8

5.6

5.3

5.3

9.4

13

13

"

9.1

229.2

7.4

13

3.9

Mean 

streamflow

(ft3/s)

227

225

221

224

221

229

224

220

218

219

223

221

219

213

211

212

211

219

210

213

208

203

194

202

227

251

251

236

231

241

ft,624

221

251

194

Suspended sediment

Mean 

concentration

(mg/L)

W9

November

10

9

9

9

9

10

10

10

11

12

12

13

14

13

12

12

10

10

9

8

8

8

9

12

14

14

13

12

12

12

...

...

11

14

8

Discharge 

(ton/d)

6.1

5.5

5.4

5.4

5.4

6.2

6.0

5.9

6.5

7.1

7.2

7.8

X.3

7.5

6.8

6.9

5.7

5.9

5.1

4.6

4.5

4.4

4.7

6.5

8.6

9.5

8.8

7.6

7.5

7.8

195.2

6.5

9.5

4.4

Mean 

streamflow

(ft3/s)

238

234

227

213

221

227

228

223

202

226

222

229

235

211

231

234

238

238

235

235

240

233

213

218

210

198

203

200

205

218

232

6,917

223

240

198

Suspended sediment

Mean 

concentration

(mg/L)

December

11

11

11

11

11

11

11

10

X

6

5

5

5

6

9

10

II

12

13

13

n

14

14

14

14

15

16

15

14

12

10

...

11

16

5

Discharge 

(ton/d)

7.1

6.9

6.7

6.3

6.6

6.7

6.8

6.0

4.4

3.7

3.0

3.1

3.2

3.4

5.6

6.3

7.1

7.7

8.2

8.2

8.4

8.8

8.1

8.2

7.9

8.0

8.8

8.1

7.7

7.1

6.3

204.4

6.6

8.8

3.0

32 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1999 through 

September 2000 (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)

210

205

203

195

207

202

201

207

207

217

209

e205

e200

227

221

221

221

213

218

211

216

215

214

213

213

212

210

208

186

186

199

6,472

209

227

186

Suspended sediment

Mean 

concentration

(mg/U

January

10

9

8

8

11

16

20

22

20

18

16

16

18

20

23

24

24

22

24

20

18

18

16

16

17

18

18

19

19

19

17

_

18

24

8

Discharge 

(ton/d)

5.7

5.0

4.4

4.2

6.1

8.7

11

12

11

11

9.0

8.9

9.7

12

14

14

14

13

14

11

10

10

9.2

9.2

98

10

10

11

9.5

9.5

9.1

306.0

9.9

14

4.2

Mean 

streamflow 

(ft3/s)

206

227

218

204

213

211

212

216

223

219

214

216

216

217

224

221

212

206

207

210

219

227

227

233

230

223

227

233

233

6,344

219

233

204

Suspended sediment

Mean 

concentration

<mg/L)

2000

February

17

18

19

18

16

17

20

22

22

22

22

23

25

25

23

20

17

22

28

34

37

34

24

16

12

16

20

23

22

-

22

37

12

Discharge 

(ton/d)

9.5

11

11

9.9

9.2

9.7

11

13

13

13

13

13

15

15

14

12

9.7

12

16

19

22

21

15

10

7.5

9.6

12

14

14

374.1

13

22

7.5

Mean 

streamflow

(ft3/s)

231

228

226

228

229

226

229

231

229

229

230

223

221

222

213

211

212

208

214

206

204

203

209

204

199

197

199

217

214

204

197

6,693

216

231

197

Suspended sediment

Mean 

concentration

(mg/L)

March

16

14

13

13

13

13

13

13

14

14

14

13

13

20

16

13

12

11

11

12

14

20

18

16

16

14

13

18

16

19

15

__

15

20

11

Discharge 

(ton/d)

10

8.6

7.9

8.0

8.0

7.9

8.0

8.1

8.7

8.7

8.7

7.8

7.8

12

9.2

7.4

6.9

6.2

6.4

6.7

7.7

11

10

8.8

8.6

7.4

7.0

11

9.2

10

8.0

261.7

8.4

12

6.2

TABLE 5 33
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1999 through 

September 2000 (Continued)

Day

j

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft-'/s)

198

206

207

207

210

205

197

187

183

183

177

175

181

190

191

186

190

191

199

204

202

192

217

216

199

194

179

168

173

175

-

5,782

193

217

168

Suspended sediment

Mean 

concentration

(mg/L)

April

15

16

14

13

20

30

18

12

19

13

9

22

24

15

13

12

15

16

14

13

22

11

23

14

8

8

10

14

10

8

...

.,_

15

30

8

Discharge 

(ton/d)

8.0

8.9

7.8

7.3

"

17

9.6

6.1

9.4

6.4

4.3

10

12

7.7

6.7

6.0

7.7

8.3

7.5

7.2

12

5.7

13

8.2

4.3

4.2

4.8

6.4

4.7

3.8

236.0

7.9

17

3.8

Mean 

streamflow

<ft3/S)

162

140

127

127

141

125

115

107

107

108

110

104

98

92

87

76

76

106

105

107

100

100

114

110

108

106

107

98

117

137

169

3,486

112

169

76

Suspended sediment

Mean 

concentration

(mg/L)

2000

Maj

11

8

8

7

6

5

5

4

5

8

6

6

7

6

4

7

5

8

6

7

8

7

13

22

10

19

10

10

12

15

39

...

9

39

4

Discharge 

(ton/d)

4.8

3.0

2.7

2.4

2.3

1.7

1.6

1.2

1.4

2.3

1.8

1.7

1.9

1.5

.94

1.4

1.0

2.3

1.7

2.0

2.2

1.9

4.0

6.5

2.9

5.4

2.9

2.6

3.8

5.5

18

95.34

3.1

18

.94

Mean 

streamflow

(frVs)

183

150

126

116

115

113

114

107

109

125

127

118

110

107

100

115

110

94

91

92

84

73

69

62

69

61

50

46

45

44

...

2,925

98

183

44

Suspended sediment

Mean 

concentration

(mg/L)

June

37

23

14

11

11

14

18

14

12

10

10

9

8

12

12

13

9

8

10

12

12

16

28

29

25

22

22

25

44

46

...

...

18

46

8

Discharge 

(ton/d)

18

9.3

4.8

3.4

3.4

4.3

5.5

4.0

3.5

3.4

3.4

2.9

2.4

3.5

3.2

4.0

2.7

2.0

2.5

3.0

2.7

3.2

5.2

4.9

4.7

3.6

3.0

3.1

5.3

5.5

...

130.4

4.3

18

2.0

34 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1999 through 

September 2000 (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)

46

57

82

101

91

75

66

60

55

49

46

42

35

33

31

31

31

28

27

28

27

26

26

26

25

24

25

28

26

26

27

1,300

42

101

24

Suspended sediment

Mean 

concentration

Img/L)

July

48

26

23

27

27

25

24

24

24

24

24

24

26

26

27

27

35

42

32

25

21

17

16

21

25

27

28

28

28

27

25

_

27

48

16

Discharge 

<ton/d)

6.0

4.0

5.1

7.4

6.6

5.1

4.3

3.9

3.6

3.2

3.0

2.7

2.5

2.3

2.3

2.3

2.9

3.2

2.3

1.9

1.5

L2

1.1

1.5

1.7

1.7

1.9

2.1

2.0

1.9

1.8

93.0

3.0

7.4

I.I

Mean 

streamflow

(frVs)

26

25

25

28

29

29

30

29

29

29

33

35

35

36

35

34

36

37

37

37

38

38

37

38

37

39

37

40

43

45

45

1,071

34

45

25

Suspended sediment

Mean 

concentration

(mg/L)

2000

August

24

25

27

30

31

32

32

33

33

33

31

27

24

23

24

25

26

26

25

25

26

25

26

26

26

26

23

21

19

19

19

26

33

19

Discharge 

(ton/d)

1.7

1.7

1.8

2.3

2.4

2.5

2.6

2.6

2.6

2.6

2.8

2.6

2.3

2.2

2.3

2.3

2.5

2.6

2.5

2.5

2.7

2.6

2.6

2.7

2.6

2.7

2.3

2.3

2.2

2.3

2.3

74.7

2.4

2.8

1.7

Mean 

streamflow

(frVs)

46

51

57

72

85

96

95

93

91

95

102

103

102

99

98

100

101

102

105

105

114

114

115

118

123

127

130

138

131

131

...

3,03")

101

138

46

Suspended sediment

Mean 

concentration

(mg/L)

September

18

20

22

25

27

27

25

25

25

26

26

23

16

12

12

14

17

22

24

20

16

15

15

15

16

16

16

16

16

16

...

19

27

12

Discharge

(ton/d)

2.2

2.8

3.4

4.9

6.2

7.0

6.4

6.3

6.1

6.7

7.2

6.4

4.4

3.2

3.2

3.8

4.6

6.1

6.8

5.7

4.9

4.6

4.7

4.8

5.3

5.5

5.6

6.0

5.7

5.7

...

156.2

5.2

7.2

2.2

TOTAL FOR WATER YEAR 2000: 

STREAMFLOW 56,928 ft3/s 

SEDIMENT DISCHARGE 2,356.24 tons

TABLE 5 35
Table 6. Daily streamflow and suspended-sediment data for Clark Fork ai Turah Bridge, near Bonner, Montana, October 1999 

through September 2000

[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)

697

712

719

718

719

731

746

748

783

775

801

811

823

811

804

818

828

837

841

830

821

811

801

804

804

816

844

920

958

934

904

24,969

805

958

697

Suspended sediment

Mean 

concentration

(mg/L)

October

5

5

6

6

6

8

10

12

14

14

14

14

14

13

12

11

10

10

9

9

9

9

8

8

8

8

10

16

18

16

14

...

11

18

5

Discharge 

(ton/d)

9.4

9.6

12

12

12

16

20

24

30

29

30

31

31

28

26

24

22

23

20

20

20

20

17

17

17

18

23

40

47

40

34

722.0

23

47

9.4

Mean 

streamflow

(ft3/s)

883

861

842

864

862

853

862

862

857

844

837

831

852

833

829

819

824

844

847

836

846

818

796

767

851

978

1,030

957

898

884

...

25,767

859

1,030

767

Suspended sediment

Mean 

concentration 

(mg/L)

1999

November

12

10

10

9

8

8

8

8

8

8

9

10

10

10

9

9

6

4

4

5

6

5

4

5

8

13

15

11

8

8

...

...

8

15

4

Discharge 

(ton/d)

29

23

23

21

19

18

19

19

19

18

20

22

23

22

20

20

13

9.1

9.1

11

14

11

8.6

10

18

34

42

28

19

19

...

580.8

19

42

8.6

Mean 

streamflow 

(ft3/s)

889

874

851

778

676

760

859

828

e750

786

807

827

848

809

785

832

854

865

869

850

843

838

766

689

634

575

528

e440

e420

436

e450

23,016

742

889

420

Suspended sediment

Mean 

concentration

(mg/L)

December

8

7

6

6

5

6

7

6

5

6

8

9

8

8

7

6

6

7

6

7

7

ft

4

2

2

2

2

3

3

4

5

6

9

2

Discharge 

(ton/d)

19

17

14

13

91

12

16

13

10

13

17

20

18

17

15

13

14

16

14

16

16

14

8.3

3.7

3.4

3.1

2.9

3.6

3.4

4.7

6.1

365.3

12

20

2.9

36 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1999 

through September 2000 (Continued)

Day

,

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/s)

e650

784

743

702

763

747

721

774

788

745

723

728

677

661

818

811

814

776

734

743

776

796

785

781

752

788

779

762

685

581

509

22,896

739

818

509

Suspended sediment

Mean 

concentration

(mg/L)

January

10

10

10

9

8

8

7

6

5

5

4

4

4

4

10

8

10

8

5

4

4

4

4

5

5

4

5

7

7

6

5

...

6

10

4

Discharge

(ton/d)

18

21

20

17

16

16

14

n

11

10

7.8

7.9

7.3

7.1

22

18

22

17

9.9

8.0

8.4

8.6

8.5

11

10

8.5

11

14

13

9.4

6.9

392.3

13

22

6.9

Mean 

streamflow 

(ft3/s)

540

812

1,130

955

838

846

837

841

871

896

836

775

825

817

817

801

754

708

684

669

728

800

869

922

880

824

802

930

1,070

-

24,077

830

1,130

540

Suspended sediment

Mean 

concentration

(mg/L)

2000

February

6

29

54

27

11

9

13

23

30

27

20

14

11

11

10

10

10

9

10

11

12

14

14

15

16

13

12

14

32

...

...

...

17

54

6

Discharge 

(ton/d)

8.7

64

165

70

25

21

29

52

71

65

45

29

25

24

22

22

20

17

18

20

24

30

33

37

38

29

26

35

92

...

...

1,156.7

40

165

8.7

Mean 

streamflow 

(ff'/s)

984

954

936

950

977

982

961

947

927

883

868

857

833

827

812

797

798

788

792

790

765

756

782

799

773

770

802

879

953

893

843

26,678

861

984

756

Suspended sediment

Mean 

concentration

(mg/L)

March

24

18

16

16

18

22

18

14

15

15

14

12

12

9

9

7

8

8

9

7

7

6

10

10

9

10

13

17

17

11

10

__

13

24

6

Discharge 

(ton/d)

64

46

40

41

47

58

47

36

38

36

33

28

27

20

20

15

17

17

19

15

14

12

21

22

19

21

28

40

44

27

23

935

30

64

12

TABLE 6 37
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1999 

through September 2000 (Continued)

Day

j

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/s)

836

838

846

833

907

978

942

890

873

884

917

944

1,020

1,150

1,170

1,130

1,120

1,120

1,160

1,190

1,220

1,260

1,330

1,340

1,250

1,190

1,140

1,120

1,220

1,190

32,008

1,067

1,340

833

Suspended sediment

Mean 

concentration

(mg/L)

April

12

12

11

13

16

21

15

14

15

15

17

18

26

33

29

22

22

22

24

24

26

28

29

27

22

16

17

16

17

12

...

20

33

11

Discharge 

(ton/d)

27

27

25

29

39

55

38

34

35

36

42

46

72

102

92

67

67

67

75

77

86

95

104

98

74

51

52

48

56

39

1,755

58

104

25

Mean 

streamflow

fft3/SI

1,120

1,150

1,200

1,240

1,280

1,240

1,180

1,110

1,100

1.080

1,070

1,010

952

910

893

897

930

968

1,000

1,060

1,080

1,150

1.260

1,280

1,220

1,190

1,180

1,200

1,350

1.280

1,330

34,910

1,126

1,350

893

Suspended sediment

Mean 

concentration

(mg/L)

2000

May

12

15

14

16

17

12

12

9

8

8

23

7

5

5

5

5

7

8

8

10

12

14

22

19

13

12

12

13

18

12

14

...

12

23

5

Discharge 

(ton/d)

36

47

45

54

59

40

38

27

24

23

66

19

13

12

12

12

18

21

22

29

35

43

75

66

43

39

38

42

66

41

50

1,155

37

75

12

Mean 

streamflow 

(ft3/s)

1,460

1.320

1,190

1,130

1,120

1,130

1,110

1,100

1,090

1,070

1,070

1,050

1,040

1,030

1,010

1,040

1,020

975

921

904

869

819

775

738

711

679

661

642

622

591

-

28,887

963

1,460

591

Suspended sediment

Mean 

concentration

(mg/L)

June

18

14

11

8

9

10

10

12

10

9

11

9

9

7

6

7

7

6

7

6

4

4

4

5

5

5

6

6

5

6

...

...

8

18

4

Discharge 

(ton/d)

71

50

35

24

27

31

30

36

29

26

32

26

25

19

16

20

19

16

17

15

9.4

8.8

8.4

10

9.6

9.2

11

10

8.4

9.6

...

658.4

22

71

8.4

38 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1999 

through September 2000 (Continued)

Day

j

2

3

4

5

6

7

8

9

1C

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

M1N

Mean 

streamflow 

(ffVs)

568

570

580

597

623

632

623

602

5%

575

542

525

535

537

511

490

480

470

463

457

450

436

419

401

384

365

351

335

319

305

284

15,025

485

632

284

Suspended sediment

Mean 

concentration

(mg/L)

July

5

5

6

6

6

7

7

7

7

8

8

9

9

9

9

9

8

8

8

8

8

8

8

7

7

6

6

6

6

6

6

_

7

9

5

Discharge 

(ton/d)

7.7

7.7

9.4

9.7

10

12

12

11

11

12

12

13

13

13

12

12

10

10

10

9.9

9.7

9.4

9.1

7.6

7.3

5.9

5.7

5.4

5.2

4.9

4.6

292.2

9.4

13

4.6

Mean 

streamflow 

(ffVs)

2000

271

264

258

258

260

261

258

255

253

257

264

265

264

259

257

253

254

263

266

270

273

276

291

299

314

312

300

286

284

280

280

8,405

271

314

253

Suspended sediment

Mean 

concentration

(mg/L)

August

5

5

5

5

5

5

5

5

5

5

5

5

5

5

4

4

3

2

2

2

3

4

4

5

5

5

4

4

4

3

4

_

4

5

2

Discharge

(ton/d)

3.7

3.6

3.5

3.5

3.5

3.5

3.5

3.4

3.4

3.5

3.6

3.6

3.6

3.5

2.8

2.7

2.1

1.4

1.4

1.5

2.2

3.0

3.1

4.0

4.2

4.2

3.2

3.1

3.1

2.3

3.0

96.7

3.1

4.2

1.4

Mean 

streamflow

(frVs)

282

309

318

324

338

372

389

393

398

401

428

437

434

428

417

410

416

415

414

422

453

468

488

498

501

504

499

497

499

520

-

12,672

422

520

282

Suspended sediment

Mean 

concentration

(mg/L)

September

4

4

4

4

5

7

9

10

10

10

10

9

9

9

9

9

9

8

8

7

7

7

8

8

9

9

9

10

11

12

-

_

8

12

4

Discharge 

(ton/d)

3.0

3.3

3.4

3.5

4.6

7.0

9.5

11

11

11

12

11

11

10

10

10

10

9.0

8.9

8.0

8.6

8.8

11

11

12

12

12

13

15

17

287.6

9.6

17

3.0

TOTAL FOR WATER YEAR 2000:

STREAMFLOW 279,310 ft3/s 

SEDIMENT DISCHARGE 8,397.0 tons

TABLE 6 39
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1999 

through September 2000

[Abbreviations: fr^/s, cubic feet per second; e, estimated; mg/L, milligrams per liter; ton/d, tons per daj. 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)

1,320

1,350

1,350

1,380

1,350

1,340

1,380

1,360

1,410

1,410

1,450

1,430

1,440

1,440

1,410

1,410

1,440

1,450

1,440

1,430

1,430

1,400

1,400

1,380

1,420

1,400

1,450

1,520

1,600

1,580

1,550

44,120

1,423

1,600

1,320

Suspended sediment

Mean 

concentration

(mg/L)

October

4

4

4

4

4

4

4

4

4

4

4

4

2

2

2

2

3

3

3

3

4

4

4

4

3

3

3

4

6

6

4

_

4

6

2

Discharge

(ton/d)

14

15

15

15

15

14

15

15

15

15

16

15

7.8

7.8

7.6

7.6

12

12

12

12

15

15

15

15

12

11

12

16

26

26

17

437.8

14

26

7.6

Mean 

streamflow

(ft3/s)

1,510

1,510

1,480

1,520

1,490

1,500

1,490

1,490

1,480

1,460

1,440

1,430

1,410

1,410

1,400

1,400

1,390

1,440

1,440

1,420

1,440

1,410

1,380

1,320

1,450

1,710

1,860

1,770

1,650

1,560

44,660

1,489

1,860

1,320

Suspended sediment

Mean 

concentration

(mg/L)

1999

November

3

3

3

3

3

3

3

4

4

4

4

4

4

4

4

4

4

5

5

5

4

4

4

4

4

6

6

5

5

5

-

...

4

6

3

Discharge

(ton/d)

12

12

12

12

12

12

12

16

16

16

16

15

15

15

15

15

15

19

19

19

16

15

15

14

16

28

30

24

22

21

...

496

17

30

12

Mean 

streamflow 

(ft3/s)

1,530

1,540

1,490

1,400

1,230

1,360

1,450

1,420

1,330

1,330

1,370

1,390

1,420

1,390

1,360

1,420

1,450

1,460

1,460

1,430

1,420

1,400

1,360

1,280

1,220

1,090

el, 000

952

905

880

990

40,727

1,314

1,540

880

Suspended sediment

Mean 

concentration

(mg/L)

December

5

4

3

2

2

3

6

6

5

4

4

4

4

4

3

3

3

3

3

3

3

3

2

1

1

2

2

2

2

2

2

_

3

6

1

Discharge

(ton/d)

21

17

12

7.6

6.6

11

23

23

18

14

15

15

15

15

II

12

12

12

12

12

12

11

7.3

3.5

3.3

5.9

5.4

5.1

4.9

4.8

5.3

352.7

11

23

3.3

40 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1999 

through September 2000 (Continued)

Day

,

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/s)

1,190

1,360

1,340

1,230

1,280

1,260

1,220

1,300

1,310

1,260

1,210

1,210

1,100

1.150

1,330

1,320

1,340

1,260

1,230

1,190

1,240

1,320

1,310

1,280

1,230

1,280

1.280

1,260

1,210

1,070

e850

38,420

1,239

1,360

850

Suspended sediment

Mean 

concentration 

(mg/L)

January

2

3

3

3

3

3

3

3

3

3

3

3

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

...

2

3

2

Discharge 

(ton/d)

6.4

11

11

10

10

10

9.9

11

11

10

9.8

9.8

5.9

6.2

7.2

7.1

7.2

6.8

6.6

6.4

6.7

7.1

7.1

6.9

6.6

6.9

6.9

6.8

6.5

5.8

4.6

2452

7.9

11

4.6

Mean 

streamflow

(ft3/s)

1,100

1,340

1,640

1,450

1,380

1,380

1,380

1,370

1,390

1,410

1,330

1,270

1,340

1,330

1.340

1,330

1,230

1,180

1,140

1,090

1.230

1,340

1,370

1,440

1,390

1,330

1,300

1,410

1.580

...

38,810

1,338

1,640

1,090

Suspended sediment

Mean 

concentration 

(mg/L)

2000

February

2

4

5

6

5

6

6

6

6

6

5

5

4

4

4

4

4

4

4

4

4

4

5

6

6

6

7

9

10

...

...

5

10

2

Discharge 

(ton/d)

5.9

14

22

23

19

22

22

22

23

23

18

17

14

14

14

14

13

13

12

12

13

14

18

23

23

22

25

34

43

...

...

551.9

19

43

5.9

Mean 

streamflow

(ft'/S)

1,490

1.500

1,470

1,530

1,570

1,620

1,620

1,620

1.610

1,540

1,510

1,500

1,470

1,460

1,460

1.410

1,460

1,390

1,480

1,420

1,450

1,400

1.470

1,550

1,530

1,560

1,650

1,840

2,080

1,960

1,880

48,500

1,565

2,080

1,390

Suspended sediment

Mean 

concentration

(mg/L)

March

11

9

7

7

7

8

8

8

8

8

7

6

7

7

4

4

5

6

9

8

7

8

8

8

6

7

8

8

12

11

Q

_

8

12

4

Discharge 

(ton/d)

44

36

28

29

30

35

35

35

35

33

29

24

28

28

16

15

20

23

36

31

27

30

32

33

25

29

36

40

67

58

46

1,013

33

67

15

TABLE 7 41
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1999 

through September 2000 (Continued)

Day

,

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

stream - 

flow

(ft3/SI

1,860

1,930

2,020

1,970

2,180

2,380

2,430

2,370

2,270

2,390

2,590

2,770

3,360

4,280

4,390

4,310

4,200

4,310

4,770

5,170

5,500

5900

6,240

6,180

5,700

5,270

4,810

4,660

4,820

4,840

1 15,870

3,862

6,240

1,860

Suspended sediment

Mean 

concentration

(mg/L)

April

9

10

9

8

10

10

8

8

9

8

10

12

16

23

21

19

17

18

22

24

25

24

26

24

21

15

15

14

14

12

...

15

26

8

Discharge 

(ton/el)

45

52

49

43

59

64

52

51

55

52

70

90

145

266

249

221

193

209

283

335

371

382

438

400

323

213

195

176

182

157

...

5,420

181

438

43

Mean 

streamflow

(ft3/s)

4,760

5,070

5,660

5,940

6,030

5,790

5,470

5,100

4,940

4,850

4,680

4,370

4,120

3,830

3,650

3,650

3,800

4,130

4,500

4,720

4,780

4,990

5,350

5,540

5,370

5,270

5,170

5,030

5,180

5,010

5,020

151,770

4,896

6,030

3,650

Suspended sediment

Mean 

concentration

(mg/L)

2000

May

12

15

20

25

25

22

18

14

12

12

11

9

9

8

8

7

10

9

9

12

12

10

13

13

12

13

12

14

13

13

12

...

13

25

7

Discharge 

(ton/el)

154

205

306

401

407

344

266

193

160

157

139

106

100

83

79

69

103

100

109

153

155

135

188

194

174

185

168

190

182

176

163

5,544

179

407

69

Mean 

streamflow

(ft3/s)

5,050

4,66(1

4,270

4,170

4,210

4,280

4,420

4,500

4,630

4,470

4,280

3,960

3,830

3,810

3,880

4,650

4,430

4,100

3,820

3,660

3,450

3,170

3,030

2,870

2,720

2,620

2,530

2,320

2,250

2,130

-

112170

3.739

5,050

2,130

Suspended sediment

Mean 

concentration

(mg/L)

June

12

12

12

8

7

6

9

11

10

9

8

7

8

8

8

13

10

6

8

9

8

7

5

6

6

5

4

5

4

4

-

8

13

4

Discharge 

(ton/d)

164

151

138

90

80

69

107

134

125

109

92

75

83

82

84

163

120

66

83

89

75

60

41

46

44

35

27

31

24

23

-

2.510

84

164

23

42 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1999 

through September 2000 (Continued)

Day

,

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/s)

2.080

1,920

1,960

1,930

1,900

1,900

1,860

1,780

1,750

1,690

1,670

1,560

1,530

1,480

1.440

1,370

1,340

1,310

1,280

1,250

1.230

1,210

1,140

1,130

1,090

1,040

1,010

984

907

905

895

44,541

1,437

2,080

895

Suspended sediment

Mean 

concentration

(mg/L)

July

5

5

4

4

3

4

4

4

4

4

4

4

4

5

5

5

5

4

4

5

4

4

4

5

5

5

4

3

3

3

3

...

4

5

3

Discharge 

(ton/d)

28

26

21

21

15

21

20

19

19

18

18

17

17

20

19

18

18

14

14

17

13

13

12

15

15

14

11

8.0

7.3

7.3

7.2

502.8

16

28

7.2

Mean 

streamflow 

(ft3/s)

2000

863

819

811

798

791

817

790

768

766

772

774

785

785

770

767

753

740

719

733

751

725

732

753

767

759

763

756

735

734

737

739

23,772

767

863

719

Suspended sediment

Mean 

concentration

(mg/L)

August

4

4

4

5

5

5

5

5

4

4

4

4

4

4

4

4

4

4

4

4

4

4

2

1

1

,

2

2

2

2

2

_

3

5

1

Discharge 

(ton/d)

9.3

8.8

8.8

11

11

11

11

10

8.3

8.3

8.4

8.5

8.5

8.3

8.3

8.1

8.0

7.8

7.9

8.1

7.8

7.9

4.1

2.1

2.0

2.1

4.1

4.0

4.0

4.0

4.0

225.5

7.3

11

2.0

Mean 

streamflow 

(ft3/*)

718

754

805

814

836

866

887

877

884

888

979

959

950

938

913

878

870

893

859

870

930

925

967

952

1,010

969

969

975

949

982

...

27,066

902

1,010

718

Suspended sediment

Mean 

concentration

(mg/L)

September

1

1

1

2

2

4

4

4

4

4

4

4

4

4

4

3

3

4

4

5

5

5

5

5

5

4

4

4

4

4

...

4

5

1

Discharge 

(ton/d)

1.9

2.0

2.2

4.4

4.5

9.4

9.6

9.5

9.5

9.6

11

10

10

10

9.9

7.1

7.0

9.6

9.3

12

13

12

13

13

14

10

10

11

10

11

...

275.5

9.2

14

1.9

TOTAL FOR WATER YEAR 2000:

STREAMFLOW 730,426 ft3/s 

SEDIMENT DISCHARGE 17,574.4 tons

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

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

reporting level; , no data]

Station 

number

12323230

12323250

12323770

12324200

12331800

12334550

12340500

Station name

Blacktail Creek at Harrison Avenue, at Butte

Silver Bow Creek below Blacktail Creek,

Warm Springs Creek at Warm Springs

Clark Fork at Deer Lodge

Clark Fork near Drummond

Clark Fork at Turah Bridge, near Bonner

Clark Fork above Missoula

at Butte

Date

04-04-00

04-04-00

06-04-00

Of 04-00

07-21-00 

07-21-00

03-06-00 

03-06-00

09-05-00

09-05-00

05-10-00

05-10-00

05-23-00

05-23-00

Time

1045

1050

1545

1550

1015 

1020

1715 

1720

1515

1520

1040

1045

1545

1550

' Calcium, Magnesium, Arsenic, total Arsenic, 

°l? dissolved dissolved recoverable dissolved

CaCCy (mS/L) (mS/L) (Ug/L) (Ug/L)

110

110

170

170

270 

280

230 

230

280

300

100

100

79

83

31

31

47

48

83 

86

66 

66

80

84

29

29

21

22

7.5

7.6

12

12

14 

15

14 

14

19

22

7.7

7.7

6.6

7.0

E2

3

10

10

12

10 

10

11

11

3

4

E2

E2

2

2

9

9

9 

9

8 

8

11

11

4

3

1

1

Station 

number

12323230

12323250

12323770

12324200

12331800

12334550

12340500

Cadmium, 

Date total recoverable

(ug/L)

04-04-00 <0.1

04-04-00 <.l

06-04-00 .9

06-04-00 1.0

07-21-00 <.)

07-21-00 <.l

03-06-00 E.1

03-06-00 E.1

09-05-00 E.1

09-05-00 <.l

05-10-00 <.l

05-10-00 <.l

05-23-00 <.l

05-23-00 <.l

Cadmium, 

dissolved 

(Hg/D

<0.1

<.l

.7

.7

<.l

<.l

<.l

<.

<.

<.

<.

<.

<.

<.

Copper, 

total 

recoverable

(ug/L)

3

3

27

27

8

8

17

18

8

8

4

4

4

4

Copper, dissolved

lug/L)

2

2

16

16

4

5

5

6

8

4

2

2

2

2

Iron, 

total recoverable

(ug/L)

340

350

240

240

40

40

270

280

90

100

100

100

170

170

Iron, 

dissolved

(ug/D

120

120

20

20

<10

<10

<10

<10

<10

<10

<10

<10

20

10

Lead, 

total recoverable

(ug/L)

<1

<1

2

2

<1

<1

2

2

<]

1

<1

<1

<1

<1

Station 

number

12323230

12323250

12323770

12324200

12331800

12334550

12340500

Lead. 

Date dissolved

lug/L)

04-04-00 <1

04-04-00 <1

06-04-00 El

06-04-00 <1

07-21-00 <1

07-21-00 <1

03-06-00 <1

03-06-00 <1

09-05-00 <1

09-05-00 <1

05-10-00 <1

05-10-00 <1

05-23-00 <1

05-23-00 <1

Manganese, total Manganese, 

recoverable dissolved

lug/L) (ug/L)

36

38

268

267

79

76

63

66

36

38

13

15

20

19

32

33

246

249

61

62

30

30

7

7

4

4

8

8

Zinc, 

total recoverable

3

3

178

179

2

2

23

23

11

11

6

7

6

6

Zinc, 

dissolved

(ug/L)

2

4

155

160

2

2

10

10

4

4

3

3

3

4

Sediment, 

suspended

(ug/L)

4

4

4

4

4

13

13

25

21

3

6

15

15

Sediment, 

suspended, 

diameter, 

percent finer 

than 0.062 mm

86

84

89

87

83

70

74

44

45

78

77

89

89

44 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork basin, Montana
Table 9. Precision of chemical and suspended-sediment analyses of field replicates for water 

samples, upper Clark Fork basin, Montana

[Abbreviations: u,g/L, micrograms per liter; mg/L, milligrams per liter: mm. millimeter]

Constituent and reporting unil

Calcium, dissolved, mg/L

Magnesium, dissolved, mg/L

Arsenic, total recoverable, u,g/L

Arsenic, dissolved, ng/L

Cadmium, total recoverable, u,g/L

Cadmium, dissolved. u,g/L

Copper, total recoverable, ng/L

Copper, dissolved, u,g/L

Iron, total recoverable, u,g/L

Iron, dissolved, u,g/L

Lead, total recoverable, ug/L

Lead, dissolved, Ug/L

Manganese, total recoverable, u,g/L

Manganese, dissolved. u,g/L

Zinc, total recoverable, ug/L

Zinc, dissolved, u,g/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

6

6

Standard 

deviation, 

in units (+/-)

1.4

.85

.46

.27

.03

.0

.27

1.1

4.6

2.7

.13

.0

1.5

.89

.38

1.5

1.2

1.5

Relative 

standard 

deviation, 

in percent (+/-)

2.7

7.2

6.4

4.3

14

.0

2.6

21

2.6

11

14

.0

2.0

1.6

1.2

5.6

11

1.9

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

[Abbreviations: u.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, (Ig/L

Cadmium, dissolved, |0.g/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, iig/L

Zinc, total recoverable, (j.g/L

Zinc, dissolved, (Ig/L

Number of 

replicate pairs

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

Standard 

deviation,1 

in units (+/-)

0.40

.13

.23

.12

.02

.01

.12

.22

6.9

5.3

.04

.10

.57

.35

.37

.25

Relative 

standard 

deviation, 

in percent (+/-)

1.2

1.4

6.0

3.4

178

6.6

3.8

14

2.1

8.5

4.7

114

1.2

1.1

8.6

9.2

Within limits of 

data-quality 

objective

Yes

Yes

Yes

Yes

Yes2

Yes

Yes

Yes

Yes

Yes

Yes

Yes2

Yes

Yes

Yes

Yes

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

Exceedance of data-quality objective 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 estimaie may not be representative of analytical performance at detectable concentrations.

46 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

[Abbreviation: Hg/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, ilg/L 

Copper, dissolved, ilg/L 

Iron, total recoverable, |^g/L 

Iron, dissolved, (ig/L 

Lead, total recoverable, iig/L 

Lead, dissolved, ilg/L 

Manganese, total recoverable, 

Manganese, dissolved, (ig/L 

Zinc, total recoverable, (ig/L 

Zinc, dissolved, (ig/L

95.1-108 

95.3-108 

96.0-114 

97.3-110 

92.4-108 

96.0-112 

92.3-102 

89.2-112 

97.3-108 

88.9-108 

93.3-108 

96.8-110 

90.0-115 

95.8-120

101.4

101.6

105.0

103.8

100.3

104.0

97.4

100.6

102.6

98.3

100.8

103.2

102.6

107.8

Yes

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes

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

[Abbreviation: ug/L, micrograms per liter]

Constituent and reporting unit Number of samples

95-percenl

confidence interval for

spike recovery,

in percent

Mean spike 

recovery, 

in percent

Within limits of

data-quality

objective

Arsenic, total recoverable, (J.g/L 

Arsenic, dissolved, (J.g/L 

Cadmium, total recoverable, Hg/L 

Cadmium, dissolved, Hg/L 

Copper, total recoverable, iig/L 

Copper, dissolved, (ig/L 

Iron, total recoverable, (ig/L 

Iron, dissolved, (J.g/L 

Lead, total recoverable, Hg/L 

Lead, dissolved, (J.g/L 

Manganese, total recoverable, (J.g/L 

Manganese, dissolved, Hg/L 

Zinc, total recoverable, iig/L 

Zinc, dissolved, (J.g/L

87.8-110 

97.5-108 

88.9-107 

100-108 

87.7-102 

97.3-106 

88.0-105 

88.3-108 

103-108 

97.3-106 

83.3-111 

91.4-112 

91.1-104 

90.9-112

98.9

102.5

98.1

104.2

94.6

101.6

96.5

98.0

105.3

101.4

97.3

101.7

97.8

101.5

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes

48 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

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

Symbol: <, less than laboratory reporting level]

Date

NOV 1999

16...

MAR 2000

06...

APR

05...

MAY

10...

23...

JUN

05...

JUL

24...

SEP

01...

Time

0630

own

1330

0700

0600

0600

0900

1600

Specific 

conductance, 

onsite

(US/cm)

2

2

2

2

2

2

2

2

pH,

onsite 

(standar 

d 

units)

5.7

5.6

5.7

5.7

5.5

5.6

5.6

5.6

r, , . Magne- Calcium, 

. j sium, dissolved 

 dissolved

<mg/L) (mg/D

0.04 E0.01

<.02 .02

<.02 <.01

<.02 <.01

<.02 <.01

E.01 <.01

<.02 <.01

<.02 <.01

Arsenic, 

total 

recoverable

<3

<3

<3

<3

<3

<3

<3

<3

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

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

, . recoverable , . recoverable 

(Mg/D (pg/L) (Mg/L) WL)

<2.0 <0.1 <0.1 <1

<.9 <.l <.l <1

<.9 <.l <.l <1

<.9 <.l <.l <1

<.9 <.l <.l <1

<.9 <.l <1 1

<.9 <.l <.l

<1

<.9 <.l <1 <1

Date

NOV 1Q99

16...

MAR 20(10

06...

APR

05...

MAY

in..

23...

JUN

05...

JUL

24...

SEP

01...

_ Iron, , Lead, Copper, Iron, Lead, 

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

 recoverable recoverable 

(^/L» (Mg/D (W!/L) (Mg/D (^/L)

<1 <20 <10 <1 <1

El <20 <10 <1 <1

<1 <20 <1" <1 <1

<1 <20 <10 <1 <1

<1 <20 <10 <1 <1

<1 <20 <10 <1 <1

<1 <20 <10 <1 <1

<1 <20 <10 <1 <1

Manga- . Zinc, 

nese, Manganese,

total dissolved 

. recoverable recoverable (Mg/L) . ,.

(Mg/L) (M8 '

<3 <1 <31

<3 <1 3

<3 <1 3

<3 <1 <1

<3 <1 <1

<3 <1 <1

<3 <1 <1

<3 <1 1

Zinc, 

dissolved

(Mg/L)

<1

<1

<1

<1

2

3

<]

<1

TABLE 13 49
Table 14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, September 2000

[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: ng/g, micrograms per gram of dry sample weight. Symbol: <, less thanj

Station number 

(fig-1)

12323600

12323750

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

1233 1800

12334550

12340000

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, 

near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek 

diversion, near Racetrack

Clark Fork ai Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Clark Fork at Turah Bridge, 

near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula1

Number 

of composite 

samples

3

3

3

3

3

3

3

3

3

3

3

3

3

3

Concentration, in ng/g

Cadmium

52.9

9.7

9.3

10.5

8.6

10.3

10.0

8.1

6.3

6.1

4.5

2.0

4.2

2.8

Chromium

16.7

17.5

19.1

26.0

19.1

16.0

23.0

24.9

22.1

23.7

16.8

15.1

19.0

12.3

Copper

4,830

272

1,110

1,650

933

1,110

1.200

748

63

391

111

18

166

87

Iron

28,200

18,100

23,600

32,800

24,700

22,000

25,300

24,400

23,100

19,400

15,400

15,400

18,100

13,400

Lead

563

63

128

200

128

130

145

105

168

82

56

13

37

25

Manganese

9,220

14,700

8,470

5,750

4,120

6,400

3,200

1.850

4,180

1,660

842

683

477

446

Nickel

15.5

15.4

15.4

16.5

12.7

10.7

13.1

14.1

11.7

11.8

9.3

9.4

11.8

8.9

Silver

13.1

<3.8

5.7

7.8

5.1

5.1

5.1

3.6

6.9

2.7

<1.9

<1.9

<1.9

<1.9

Zinc

13,400

1,090

1,090

1,490

1,170

1,370

1,340

1,090

588

948

786

35

438

252

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

50 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork Basin, Montana
Table 15. Trace element analyses of bulk bed sediment, upper Clark Fork basin, Montana, September 2000

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

Station number 

(fig- 1)

12323600

12323750

12323800

461415112450801

461559112443301

46 1903 II 2440701

12324200

12324680

12331500

12331800

12334550

1234000

12340500

12353000

Station name

Silver Bow Creek at Opportunily

Silver Bow Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek diversion, 

near Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Clark Fork at Turah Bridge near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula1

Number 

of composite 

samples

2

2

2

2

2

2

2

2

2

2

2

2

2

2

Concentration, in (ig/g

Cadmium

20.6

<1.9

8.2

3.3

6.6

9.2

7.8

7.6

<1.9

2.5

3.3

<1.9

3.4

<1.9

Chromium

12.0

5.9

23-7

10.8

19.1

21.1

20.6

21.4

5.1

6.9

10.3

12.5

15.0

4.8

Copper

1,660

20

902

305

603

1,000

906

709

16

114

186

18

128

32

Iron

19,000

7,590

25.700

16,000

25,900

24,900

22,800

21,500

1 1,700

12,100

12,600

14,600

16,800

9,800

Lead

278

12

113

58

86

115

112

92

56

32

39

11

28

»

Manganese

5,480

2.100

9,490

1,440

1,710

4,930

2,530

2,930

1,690

979

932

652

570

364

Nickel

8.7

5.6

15.2

5.3

9.1

10.8

11.8

13.0

4.9

7.8

8.3

9.3

11.1

5.6

Silver Zinc

7.4 5,690

<1.9 98

5.2 1,140

<1.9 417

2.7 781

4.4 1,240

3.9 1,060

3.2 986

2.5 178

<1.9 397

<1.9 501

<1.9 35

<l.9 336

<l.9 134

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

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

[Abbreviations: (ig/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

6

6

6

6

6

6

6

6

6

7

7

7

7

7

7

7

7

7

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)

-

72.2

91.8

91.5

83.1

93.1

86.3

80.2

107.6

50.7

96.6

87.3

101.1

82.7

83.8

99.5

84.4

95-percent confidence 

interval for SRM 

recovery 

(percent)

--

70.3-74.0

90.0-93.7

90.8-92.2

81.8-84.4

91.7-94.5

84.8-87.9

-

73.4-87.1

107-108

47.1-54.3

95.4-97.9

84.3-90.3

100-102

79.7-85.6

82.1-85.4

95.7-103

79.4-89.4

52 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

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

reagent to final volume of solution after addition of 0.6 N hydrochloric acid used for reconstituting dried residue. Symbols: <, less than]

Station number

12323600

12323750

12323800

461415112450801461559112443301461903112440701

1232420012324680

12331500

1233180012334550123400001234050012353000

Station name

Silver Bow Creek at OpportunitySilver Bow Creek at Warm Springs

Clark Fork near GalenClark Fork below Lost Creek, near GalenClark Fork near Racetrack

Clark Fork at Dempsey Creek diversion, near Racetrack

Clark Fork at Deer LodgeClark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near DrummondClark Fork at Turah Bridge, near Bonner

Blackfoot River near BonnerClark Fork above Missoula

Clark Fork below Missoula

Dilution 

ratio

1:10

1:10

1:10

1:10

1:101:10

1:10

1:5

1:5

1:5

1:5

1:5

1:5

1:5

Trace-element concentration, in ^g/mL

Cad- Chromium mium

<0.01 <0.003

<.01 <.003

<.01 <.003

<.01 <.003<.01 <.(X)3<01 <.003

<.01 <.003<01 <.003<.01 <.003

<01 <.003<.01 <.003

<.01 <.003<.01 <.003

<.01 <.003

Copper

<0.002

<.002

<.002

<.002<.002<.002

<.002<.002<.002

<.002<.002

<.002<.002

<002

Iron

<0.02

<.02

<.02

<02<.02<.02

<.02<.02

<.02<.02<.02

<.02

<.02<.02

Lead

<0.002

<.002

<.002

<002<.002<.002

<.002<.002

<.002<.002<.002

<.002

<.002<002

Manganese

<0.036

<.036

<.036<.036<.036

<.036

<036<.036<.036<.036

<.036

<.036<.036<.036

Nickel Silver

<0.001 <0.01

<.001 <01

<001 <.01<.001 <.01<001 <.01

<.001 <.01

<.001 <01<.001 <01<.001 <.()!<001 <.01<.001 <.01<.001 <01

<.001 <01<.001 <.01

Zinc

<0.042

<.042

<.042

<.042

<.042<.042

<.042<.042<.042<.042<.042

<.042<.042

<.042

PI
Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, September 2000

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

Taxon

Brachycentrus spp.

Hydropsyche spp.

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche cockerelli

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche spp.

Claassenia sahulnsa

Number of Concentration,

composite Cad- Chro- Copsamples mium mium per

12323600 Silver Bow Creek at Opportunity

1 8.4 5.9 235 469

1 5.0 4.6 352 1,430

12323750 Silver Bow Creek at Warm Springs

1 .4 .6 29.9 825

3 .4 .9 31.4 1,010

12323800 Clark Fork near Galen

6 1.0 2.1 122 [.950

1 1.2 2.6 94.9 1,530

461415112450801 Clark Fork below Lost Creek, near Galen

3 1.5 2.5 97.2 1,220

1 -3 2.0 70.1 189

461559112443301 Clark Fork near Racetrack

1 1.0 1.0 82.6 981

1 1.2 1.4 124 1,760

1 1.5 1.7 85.2 1,200

1 .4 .2 40.3 113

in u,g/g

Lead

13.7

36.5

2.5

2.8

9.3

10.1

98

1.3

6.1

10.3

7.4

.8

Manganese

666

1,040

2,520

3,080

2,450

6.170

3.050

238

1,960

2,050

1.600

172

Nickel

1.6

2.2

1.2

1.5

1.7

2.0

1.4

.2

1.2

1.9

1.4

2

Zinc

815

1,090

167

180

242

286

240

245

198

255

208

213

461903112440701 Clark Fork at Demosev Creek diversion, near Racetrack

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cnckerelli

Hydropsyche occidentalis

2 .7 1.6 64.6 927

3 1.2 2.6 91.8 1,440

12324200 Clark Fork at Deer Lodge

3 .7 1.9 84.6 1,120

3 1.1 2.3 144 1,600

12324680 Clark Fork at Goldcreek

1 1-1 1.2 31.5 673

2 .5 .4 54.3 123

1 1.1 2.3 65.1 1,610

1 1.3 2.0 58.3 1,360

12331500 Flint Creek near Drummond

2 .2 1.6 16.3 1,390

1 .3 3.2 16.8 3,390

1 .2 3.6 27.3 2,990

12331800 Clark Fork near Drummond

3 .6 .9 27.3 600

3 .3 .4 50.4 156

4 .8 1.7 51.5 1,330

1 .9 2.4 57.4 1,810

8.4

12.1

11.0

13.6

6.6

.9

13.2

13.3

13.3

28.4

29.8

5.4

1.2

10.3

12.8

1,160

1,540

1,290

1,700

1,580

154

1,670

2,210

2.080

2,460

4,790

1,020

211

1,650

1,390

1.0

1.6

.9

1.7

1.1

.3

1.8

1.9

1.5

2.3

2.3

.8

.3

1.5

2.0

174

238

197

267

216

342

249

277

205

208

205

198

264

245

293

54 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

upper Clark Fork Basin, Montana
Table 18. Trace-element analyses of biota, upper Clark Fork basin. Montana, September 2000 (Continued)

Taxon

Number 

composite 

sample

of Concentration, in ng/g

Cad- Chro- Cops mium mium per

Iron Lead

Manganese

Nickel Zinc

12334550 Clark Fork at Turah Bridge, near Bonner

Arctopsyche grandis

Claassenia sahulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

4

1

3

2

.8

.4

.5

.8

1.8

<.l

1.7

2.7

43.1

50.8

44.4

63.1

1.180

61

1,320

1,830

6.8

<.7

6.5

11.2

701

37

688

1.260

2.4

<.l

1.6

2.5

242

214

199

326

12340000 Blackfoot River near Bonner

Arctopsyche grandis

Claassenia sabulosa

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

1

2

1

2

2

2

2

3

2

2

.4

<.l

12340500

.6

.2

.4

.4

12353000

.2

.1

.3

.3

.8

.3

12.9

42.6

525

52

.5

.1

286

33

1.0

.1

138

258

Clark Fork above Missoula

1.9

.8

2.0

2.2

Clark Fork below

.9

.3

1.1

1.1

27.8

57.5

31.5

31.2

1,410

340

1,460

1,470

3.9

1.2

4.3

4.1

1.210

477

1,190

1,560

1.8

.5

1.5

1.6

224

362

170

202

Missoula'

16.7

45.1

16.7

16.1

533

98

645

814

1.2

.2

1.3

1.5

803

130

1.120

966

.9

.1

.7

.9

163

270

121

457

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

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

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

_ . »» 95-percent confidence

_ ml Certified concentration Mean SKM recovery . Constituent Number of measurements , . , interval for SRM recovery (ug/g) vr&6 (percent) F .(percent)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

11

11

11

11

'o

11

11

11

SRM sample TORT-2

26.7

.77

106

105

.35

13.6

2.5

180

103

163

88.5

94.4

-

95.9

88.3

94.6

102-104

163-164

85.9-91.2

91.0-97.7

-

95.5-96.2

88.2 88.4 *

87.2-102

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

56 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

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

Trace-element concentration, in ng/mL

number

12323600

12323750

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334550

12340000

12340500

12353000

name ratio

Silver Bow Creek at Opportunity 1 : 1

Silver Bow Creek at Warm Springs 1 : 1

Clark Fork near Galen 1 : 1

Clark Fork below Lost Creek, near 1 : 1

Galen

Clark Fork near Racetrack 1 : 1

Clark Fork at Dempsey Creek diver- 1 : 1 

sion, near Racetrack

Clark Fork at Deer Lodge 1 : 1

Clark Fork at Goldcreek 1 : 1

Flint Creek near Drummond 1 : 1

Clark Fork near Drummond 1 : 1

Clark Fork at Turah Bridge, near Bonner 1 : 1

Blackfoot River near Bonner 1 : 1

Clark Fork above Missoula 1 : 1

Clark Fork below Missoula 1 : 1

Cadmium

<0.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

Chromium

<0.01

<.01

<.01

.02

<.01

.02

<.01

.02

<.01

.02

.02

<.01

<.02

.01

Copper Iron

<0.02 <0.10

<.02 <.10

<02 <.10

<.02 <.10

<.02 <.10

<.02 <.10

<.02 <.10

<.02 <.10

<.02 <.10

<.02 <.10

<.02 <.10

<.02 <.10

<.02 <.10

<.02 <.10

MangaLead & 

nese

<0.01 <0.02

<.01 <.02

<.01 <.02

<.01 <.02

<.01 <.02

<.01 <.02

<.01 <.02

<.01 <.02

<.01 <.02

<.01 <.02

<.01 <.02

<.01 <.02

<.01 <.02

<.01 <.02

Nickel

<0.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

<.002

Zinc

<0.02

<.02

<.02

<02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

<.02

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

through September 2000

[Abbreviations: ft3/s. cubic feet per second; °C, degrees Celsius; jig/L, micrograms per liter; jiS/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 . Maximum samples

Minimum

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

Period of record for water-quality data:

Streamflow, instantaneous (f rYs)

Specific conductance, onsite (u5/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (u.g/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (u.g/L)

Lead, total recoverable (u.g/L)

Lead, dissolved (u,g/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (u.g/L)

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

March

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59

1993-August 1995,

156

412

17.5

8.2

140

40

11

18

13

<1

.5

52

10

4,200

480

47

1

240

100

130

11

139

59

97

Mean

MONT.

Median

December 1996-September 2000

2.4

116

2.0

7.3

38

11

2.7

2

1

<.l

<.l

2

<1

139

23

<1

<.5

30

17

<10

<3

2

.02

50

17

257

8.2

7.8

102

29

7.1

6

4

-

-

8

24

788

182

23

2.3

62

42

2 12

24

17

1.9

84

8.4

259

8.0

7.8

100

30

7.1

5

3

<1

<.l

6

3

590

170

1

<.5

60

39

<40

2

7

.18

86

58 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

through September 2000 (Continued)

Property or constituent and reporting unit

12323250-SILVER BOW CREEK

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite ((xS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (.ng/L) 

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

Number of 

samples

BELOW BL

Maximum Minimum

ACKTAIL CREEK. AT BUTTE.

Mean

MONT.

March 1993-August 1995, December 1996-September 2000

59 134 13 33

59

59

59

59

59

59

59

59

59

59

59

59

59

59

59 

59

59

59

59

59

58

58

58

691

20.0

8.1

180

52

13

45

13

6

6.2

550

300

7,400

270

250 

2.4

1,600

1,700

2,200

2,200

405

70

98

226

1.5

7.2

66

19

4.5

7

4

.7

.2

16

7

92 1

18

1 

<5

176

161

178

118

3

.14

42

459

10.2

7.6

146

42

10

15

7

2.6

1.9

152

65

,340

97

24 

2.8

637

578

778

637

36

4.6

83

Median

26

470

9.0

7.6

150

43

11

13

7

2

1.5

130

51

820

84

11 

<1

630

580

700

540

14

1.2

86

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

through September 2000 (Continued)

Property or constituent and reporting unit

12323600--SILVER

Number of 

samples

BOW CREEK

Maximum Minimum Mean Median

AT OPPORTUNITY, MONT.

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

Streamflow, instantaneous (ft3/s) 62 361

Specific conductance, onsite (uS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCCX,)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (u.g/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L) 

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

61

61

61

61

61

61

61

61

61

61

61

61

61

61

61 

61

61

61

61

61

62

62

62

616

22.5

Q.5

210

62

15

240

34

49

41

3,900

450

24,000

310

650 

5.1

10,000

9.300

15,000

13,000

801

781

95

December 1996-September 2000

15 86

202

0.0

7.2

60

18

3.4

11

1

.6

.1

62

19

276

3

7 

<.5

174

68

144

27

6

.28

37

384

9.1

8.3

137

40

8.7

32

10

3.0

1.8

293

61

2,010

53

51

2.8

748

615

789

480

68

32

77

57

370

9.5

8.3

130

40

84

18

9

2.0

1.1

140

47

910

27

17 

<1

570

470

500

260

20

3.2

80

60 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

through September 2000 (Continued)

Property or constituent and reporting unit

12323750--SILVER

Number of 

samples Maximum Minimum Mean Median

BOW CREEK AT WARM SPRINGS. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s) 68

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3 )

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (jig/L)

Cadmium, total recoverable (jig/L)

Cadmium, dissolved (n-g/L)

Copper, total recoverable (jig/L)

Copper, dissolved (ng/L)

Iron, total recoverable (jig/L) 

Iron, dissolved (jig/L) 

Lead, total recoverable (M-g/L)

Lead, dissolved (.ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (M-g/L) 

Zinc, total recoverable (jig/D 

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

66

67

66

66

66

66

66

66

66

66

66

66

66 

66 

66

66

66

66 

66 

66

68

68

67

March

662

682

22.0

9.3

290

85

19

94

60

.1

.3

80

40

3,000 

93 

15

1.0

600

530 

180 

73

229

279

97

1993-September 2000

16

249

.5

8.0

97

28

5.9

12

8

<.l

<1

5

3

72 

<5

<5

60

12 

<3

1

11

43

166

445

11.0

8.8

184

54

12

26

21

-

2.1

22

11

403 

2 18 

23

-

191

120 

249 

2 12

14

11

82

118

431

12.0

8.8

180

52

12

24

21

<1

<.l

19

10

300 

15 

2

<5

160

96

30 

7

7

2.0

85

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

through September 2000 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum

12323770--WARM SPRINGS CREEK AT WARM

Period of record

Streamflow, instantaneous (ft'/s)

Specific conductance, onsite (uS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ug/L)

Arsenic, dissolved (ug/L)

Cadmium, total recoverable (ug/L)

Cadmium, dissolved (ug/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L) 

Lead, total recoverable (ug/L)

Lead, dissolved (ug/L)

Manganese, total recoverable (ug/D

Manganese, dissolved (ug/L) 

Zinc, total recoverable (.ug/L) 

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

for water quality data:

46

45

46

45

45

45

45

45

45

45

45

45

45

45

45 

45

45

45

45 

45 

45

46

45

46

Minimum

SPRINGS. MONT.

Mean Median

March 1993-September 2000

420

795

18

8.7

420

130

22

27

14

.2

<.l

97

16

1,700

30 

14

1.8

1,400

570 

60 

10

100

87

88

2.8

139

.5

7.4

66

20

3.6

3

2

<.l

<.l

2

1

40

<5

<1

<.5

80

41 

<10 

<1

2

.05

55

112

303

9.1

8.3

147

45

8.5

8

5

-

-

23

4

372

11

22

-

252

152

2 13 

23

22

12

75

72

267

9.2

8.3

130

40

7.3

6

4

<1

<.l

11

3

160

9

1

<.5

204

110 

2 

<10

10

1.6

75

62 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

through September 2000 (Continued)

Property or constituent and reporting unit Number of 

samples

12323800--CLARK FORK

Period of record

Streamflow, instantaneous (ft /s)

Specific conductance, onsite (|iS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO-j)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (|ig/L)

Arsenic, dissolved (M-g/L)

Cadmium, total recoverable (u.g/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 (|Ag/L)

Lead, dissolved (|ig/L)

Manganese, total recoverable (|ig/L)

Manganese, dissolved t.|ig/L)

Zinc, total recoverable (Hg/L)

Zinc, dissolved (|ig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

Maximum

NEAR GALEN,

Minimum

MONT.

Mean Median

for water-quality data: July 1988-September 2000

109

97

108

96

95

95

95

95

95

95

95

94

95

95

95

95

95

95

95

95

95

109

109

108

1,050

720

22.5

9.0

370

110

22

78

53

3

1

240

50

9,200

110

28

3

1,400

380

360

110

338

459

97

14

197

0.0

7.5

81

24

5.1

3

4

<.l

<.l

5

3

79

<3

<1

<.5

80

31

<10

<3

2

.12

41

224

426

9.7

8.5

187

55

12

20

15

2.2

2.05

35

10

608

2 17

24

2.3

270

120

255

2 14

22

26

78

136

435

10.0

8.5

190

55

12

16

13

<1

<.l

21

9

320

12

2

<.5

200

89

40

9

9

2.5

78

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

through September 2000 (Continued)

Property or constituent and reporting unit

12324200--CI

Number of ... 

, Maximum samples

>ARK FORK

Period of record for water-quality

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ug/L)

Arsenic, dissolved (ug/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ug/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L)

Lead, total recoverable (ug/L)

Lead, dissolved (ug/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm;

161

144

160

109

101

101

101

111

111

111

111

110

111

111

111

111

111

111

111

111

111

161

161

152

AT DEER LODGE.

Minimum

MONT.

Mean Median

data: March 1985-September 2000

1,920

642

23.0

8.9

270

81

18

220

39

5

2

1,500

120

29,000

190

200

6

4,600

400

1,700

230

2.250

8,690

99

23

234

0.0

7.4

95

28

5.9

8

7

<.l

<.l

10

4

60

<3

<1

<.5

30

1

10

<10

2

.29

40

304

487

9.6

8.2

204

60

13

27

14

2.5

2.06

103

13

2.010

2 16

2 13

2.5

303

45

117

2 16

85

195

71

227

506

10.0

8.2

210

62

14

18

13

<1

<.l

46

9

710

9

5

<.6

170

32

60

11

24

12

71

64 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

through September 2000 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12324590-1 TTTJLE BLACKFOOT RIVER NEAR GARRISON. MONT.

Period of record

Streamflow, instantaneous (ft /s)

Specific conductance, onsite (uS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO,)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ug/L)

Arsenic, dissolved (ug/L)

Cadmium, total recoverable (ug/L)

Cadmium, dissolved (ug/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L)

Lead, total recoverable (ug/L)

Lead, dissolved (ug/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

for water-quality data:

90

78

89

77

72

72

72

77

77

77

77

76

77

77

77

77

76

77

77

77

77

90

90

90

March 1985-September 2000

2,080

338

22

8.5

160

47

10

17

7

2

1

45

7

25,000

120

25

6

1,100

30

140

24

1,410

7,920

97

15

120

0.0

7.0

51

14

3.3

4

3

<.l

<.l

<1

<1

20

<3

<1

<.5

<10

1

<1

<1

1

.08

32

296

227

8.3

8.1

104

30

7.0

7

5

2.3

-

25

22

1.240

235

23

2.4

274

9

2 13

24

54

152

75

178

220

9.0

8.1

100

30

7.0

6

5

<1

<.l

3

2

260

23

<5

<1

30

8

<31

<20

9

4.0

79

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

through September 2000 (Continued)

Property or constituent and reporting unit

12374680-

Number of . Maximum samples

-CLARK FORK

Period of record for water-quality

Streamflow, instantaneous (ft3/s) 67

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L) 

Iron, dissolved (ng/L) 

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/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)

66

67

66

66

66

66

66

66

66

66

65

65

66 

66 

65

65

66

66

66 

66

67

67

67

AT GOLDCREEK

Minimum

MONT.

data: March 1993-September 2000

3,920 87

510

21.5

8.8

230

68

15

75

20

2

.2

440

36

12,000 

100 

73

.8

1,100

43

510 

26

752

7,960

93

207

0.0

7.9

86

26

5.1

8

6

<.l

<.l

8

3

60 

<3

<.5

30

7

8 

<3

2

.94

43

Mean

825

368

9.5

8.3

161

47

10

17

10

2.1

-

51

8

1,100 

2 19 

27

-

147

20

60 

28

64

318

75

Median

562

386

9.5

8.3

170

50

II

14

10

<l

<.l

34

6

530 

13

4

<.5

100

20

40 

5

24

38

78

66 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

through September 2000 (Continued)

Property or constituent and reporting unit Number of 

samples

12331500-FLINT CREEK NF* R

Period of record

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (iiS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCOj)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (iig/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

for water-quality data:

116

105

114

102

95

95

95

102

102

102

102

101

102

102

102

102

102

102

102

102

102

116

113

116

Maximum Minimum Mean Median

DRUMMOND. MONT.

March

892

529

21.0

8.8

260

73

20

57

20

3

.1

32

7

7,200

240

87

7

1,600

120

290

27

556

904

98

1985-September 2000

2.8

134

0.0

7.5

59

16

4.3

7

5

<.l

<.l

1

<1

69

3

<1

<.5

50

14

<10

<3

3

.02

28

193

297

8.9

8.3

139

38

11

18

9

2.2

--

7

22

947

40

2 12

2.7

216

40

240

26

52

48

80

122

299

9.2

8.3

140

38

U

14

8

<l

<.l

5

2

520

26

7

<1

136

34

30

3

28

8J$

84

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

through September 2000 (Continued)

Property or constituent and reporting unit Number of 

samples

12331800--CLARK FORK NEAR

Period of record

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (|xS/cm)

Temperature, water (UC)

pH. onsite (standard units)

Hardness, total (mg/L as CaCO3 )

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (|Xg/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (Hg/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

for water-quality data:

67

66

67

66

66

66

66

66

66

66

66

64

64

66

66

62

62

66

66

66

66

67

67

67

Maximum Minimum Mean Median

DRUMMOND. MONT.

March

3,860

630

22.5

8.5

300

83

22

62

20

2

.2

360

21

8.800

150

56

1.2

880

50

490

21

530

4,720

92

1993-September 2000

149

189

.5

7.8

74

21

5.2

8

7

<.l

<.l

5

1

50

<3

<1

<5

20

7

9

<3

2

1.9

38

1,150

400

10.5

8.3

180

52

12

18

11

2.2

-

51

7

1,210

221

29

2.3

168

17

76

28

76

420

73

842

429

11.0

8.3

190

55

13

14

10

<1

<.l

26

6

580

9

4

<5

110

15

41

6

30

66

74

68 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

through September 2000 (Continued)

Property or constituent and reporting unit

12334510-ROCK

Number of . 

, Maximum samples

CREEK

Period of record for water-quality

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (uS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L)

Lead, total recoverable (ug/L)

Lead, dissolved (ug/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

89

80

89

79

71

71

71

77

77

77

77

75

76

77

77

75

75

77

77

77

77

89

89

89

NEAR CLINTON,

Minimum

MONT.

Mean Median

data: March 1985-September 2000

5,060

158

18

8.8

90

23

8.0

3

1

3

1

41

6

2,100

160

19

5

90

8

60

15

223

3,050

95

113

53

0.0

6.9

22

5.9

1.9

<1

<1

<.l

<.l

<1

<1

20

5

<1

<.5

<l

<3

<1

<1

1

.31

35

1,020

105

8.1

7.9

49

13

4.2

2.9

2.7

2.3

-

24

2 1

336

37

22

2.5

2 17

22

28

22

23

161

69

558

96

8.5

7.9

49

13

4.0

<1

<1

<1

<.l

2

<1

150

33

<1

<l

10

2

<10

<3

6

12

70

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

through September 2000 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean

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

Period of record for water-quality data: March 1985-September 2000

Streamflow, instantaneous (ft3/s) 164 9,560 296 1,900

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 (ug/L)

Arsenic, dissolved (ug/L) 

Cadmium, total recoverable (ug/L)

Cadmium, dissolved (ug/L)

Copper, total recoverable (ug/L)

Copper, dissolved (,M-g/L)

Iron, total recoverable (ug/L) 

Iron, dissolved (ug/L) 

Lead, total recoverable (ug/L) 

Lead, dissolved (ug/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (Ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer dian 0.062 mm)

139

163

110

100

100

100

109

109 

109

109

107

108

109 

109 

105 

105

109

109

109

109

164

164

153

483

22.0

8.8

210

59

14

110

17 

4

1

500

25

19,000 

190 

100 

7

2,000

37

1,100

39

1,370

34,700

98

140

0.0

7.4

58

16

3.9

3

3

<.l

3

2

50 

<3

10

1

<10

<3

2

3.5

27

306

9.2

8.2

133

38

9.5

11

6

2.3

-

43

5

1,300 

226 

29 

2.4

151

8

27?

2R

64

744

72

Median

1,120

327

9.5

8.2

140

39

9.5

8

5

<.l

21

4

480 

14

5

80

7

40

6

20

61

72

70 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

through September 2000 (Continued)

Property or constituent and reporting unit

12340000--BI

Number of 

samples Maximum Minimum Mean Median

.ACKFOOT RIVER NEAR BONNER. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (fr/s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (.ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

120

97

120

80

73

73

73

80

80

80

80

77

78

80

80

76

76

80

80

80

80

120

120

118

March

13,400

294

21.0

8.7

140

37

13

4

2

2

1

34

7

3,600

100

25

8

180

11

60

15

271

7,670

98

1985-September 2000

344

130

0.0

7.5

55

14

4.9

<1

<1

<.l

<.l

<1

<1

20

<3

<1

<.5

<10

<1

<1

<1

1

1.1

42

2,770

205

9.1

8.3

101

26

8.9

2 1

2.9

2 .4

-

27

22

548

2 19

24

2.9

236

23

28

23

33

613

79

1,320

203

9.2

8.3

95

24

8.4

1

.8

<1

<.l

4

1

232

12

1

<1

20

2

<10

<10

9

31

81

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

through September 2000 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum

12340500-CLARK FORK ABOVE MISSOl

Period of record for water-quality

Streamflow, instantaneous (fr/s)

Specific conductance, onsite (u,S/cm)

Temperature water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (u,g/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (u,g/L)

Cadmium, dissolved (u,g/L)

Copper, total recoverable (ng/L)

Copper, dissolved (u,g/L)

Iron, total recoverable (ug/L)

Iron, dissolved (u,g/L)

Lead, total recoverable (u,g/L)

Lead, dissolved (u,g/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (u,g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

130

107

127

87

87

87

87

87

87

87

87

85

86

87

87

82

82

87

87

87

87

130

130

125

Minimum

JLA. MONT.

Mean Median

data: July 1986-September 2000

21,600

399

20.0

8.7

170

46

13

69

9

5

.1

400

11

13,000

200

78

1

1,100

230

1,100

16

824

21,900

99

720

142

0.0

7.9

61

14

5.3

1

I

<.l

<.l

2

.7

56

<3

<1

<.5

10

6

<10

<3

2

6.1

44

4,550

254

9.2

8.3

117

32

9.2

5

3

-

-

17

3

673

223

24

2.6

69

18

234

25

39

1,070

87

2,360

261

8.5

8.3

120

32

9.2

4

3

<1

<.l

8

2

230

16

2

<.5

40

14

20

3

10

62

90

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

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

72 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

August 1986 through September 2000

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

weight. Symbols: <, less than minimum reporting level; , indicates insufficient data greater than the minimum reporting level to 

compute statistic. Number of samples represents the number of years that the constituent was analyzed, with each year represented by a 

single mean concentration of composite samples]

Number .

Constituent of

, mum samples

Minimum Mean Median

12323600--SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for fine-grained bed-sediment data: 1992-2000

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

9 42.0

8 32.4

9 6,280

9 41.200

9 1,030

9 9,220

8 21.4

9 19.6

9 13,400

23.7 31.5

23.2 27.7

4,220 4,990

28.200 37,300

563 817

1,680 3,280

14.2 16.3

13.1 16.3

6.660 8.660

29.3

27.9

4,810

38,400

833

2.460

16.1

16.4

8,010

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.

Period of record for fine-grained bed-sediment data: 1992-2000

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

9 12.2

8 34.1

9 769

9 27,200

9 100

9 17,700

8 19.1

9 2.1

9 2,220

4.5 7.8

12.8 22.1

223 416

18.100 21,600

58 75

1,470 7,390

12.5 15.5

.3 '1.4

620 1.150

6.7

23.2

344

20,800

73

7.230

15.6

'1.6

840

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

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

3 3.9

3 33.4

3 892

3 22,400

3 86

3 8,790

3 21.9

3 3.7

3 421

1.3 2.6

27.5 30.6

779 840

20,600 21.600

85 85

2,020 5,610

17.6 197

3.1 3.3

372 396

2.6

30.8

848

21,900

85

6.030

19.6

3.2

396

12323800--CLARK FORK NEAR GALEN. MONT.

Period of record for fine-grained bed-sediment data: 1987, 1991-2000

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

11 20.1

8 33.9

11 2,300

11 39,800

11 235

11 15,600

8 23.2

11 5.7

1 1 3,560

4.0 10.3

19.1 27.2

991 1,330

22.600 29.000

116 150

2,780 8,460

15.4 19.3

<3.2 '4.0

1,090 1,840

9.3

28.5

1,220

28,400

143

8.470

19.2

'3.7

1,370

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

August 1986 through September 2000 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

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

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

Period of record for fine-grained bed-sediment data: 1996-2000

5 10.5 6.5 8.2

5 34.5 25.6 30.5

5 2,050 1,360 1,650

5 32.800 30.800 31,900

5 200 168 186

5 5,900 3,540 4,830

5 19.9 16.5 18.3

5 7.8 4.2 6.3

5 1,680 1.280 1.480

461559112443301-CLARK FORK NEAR RACETRACK. MONT.

Period of record for fine-grained bed-sediment data: 1996-2000

5 8.6 5.0 7.0

5 33.3 19.1 27.5

5 1,610 933 1,250

5 31.700 24,700 28,800

5 186 128 151

5 4,120 2,390 3,270

5 18.4 12.7 16.2

5 6.1 <3.3 !4.7

5 1,550 1.030 1,270

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

Period of record for fine-grained bed-sediment data: 1996-2000

5 10.3 4.3 6.9

5 34.1 16.0 27.3

5 1,550 766 1,110

5 33,700 22,000 28,500

5 152 115 133

5 6,410 1,810 3,490

5 16.9 10.7 15.1

5 6.2 2.7 4.8

5 1,570 900 1,200

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1990-2000

13 1 0.0 4.4 7.0

8 43.9 19.5 31.9

13 4,180 837 1,490

13 35,300 22,600 28,500

13 242 121 160

13 6,020 1,460 2,850

8 21.1 13.1 17.2

13 7.9 2.4 4.8

13 1,730 977 1,340

Median

8.4

32.0

1,650

31,700

190

5,000

18.7

6.8

1,4QO

7.5

30.0

1,370

29,000

153

3,130

16.7

'5.1

1,190

MONT.

6.9

28.3

1,110

28,300

130

2,680

15.8

5.1

1,260

7.4

33.9

1,200

29,400

155

2,440

17.2

4.6

1,340

74 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

August 1986 through September 2000 (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

4 1.5 .2 .8

2 52.9 22.1 37.5

4 85 38 60

4 30,700 16,100 24,200

4 53 36 41

4 2,700 905 1,390

2 21.9 L3.6 17.8

4 .9 <5 '.6

4 204 161 179

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for fine-grained bed-sediment data: 1992-2000

9 8.1 3.5 5.7

8 48.9 24.9 34.5

9 1,080 653 823

9 30,600 20,500 25,700

9 152 88 113

9 2,610 1,180 1,930

8 18.6 14.1 16.5

9 4.8 2.3 3.5

9 1,320 1,070 1,150

12331500--FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for fine-grained hed-sediment data: 1986, 1989. 1992-2000

11 6.3 <2 '2.7

8 29.2 20.4 24.4

11 73 55 62

11 28,100 21,100 24,000

11 240 150 179

11 5,510 2,370 3,830

8 14.9 11.7 12.9

10 7.8 5.0 6.3

11 777 577 659

12331800--CLARK FORK NEAR DRUMMOND. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1991-2000

12 6.1 2.6 4.5

8 35.4 17.0 29.2

L2 747 391 546

12 27,000 16,500 22,600

L2 135 82 99

12 2,790 1,220 1,840

8 16.8 11.8 15.1

12 4.7 <3.2 '2.9

12 1,230 939 1,070

Median

.8

59

25,100

38

974

1 .6

175

5.8

33.2

780

25,300

118

1,840

16.7

3.6

1,120

'2.4

24.1

63

23,500

174

3,910

12.6

6.5

650

4.6

31.3

551

23,500

98

1,810

15.7

'2.8

1,070

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

August 1986 through September 2000 (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 ri JNTON. MONT.

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

12 <1.5 <.2 '--

7 27.9 16.5 22.6

12 16 3 12

12 21,400 13,100 18,100

12 16 <3 '8

12 724 126 405

7 14.8 10.8 12.9

11 .8 <.3 '.4

12 58 36 48

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

Period of record for fine-grained bed-sediment data: 1986, 1991-2000

11 5.2 3.1 3.9

8 34.7 15.3 25.2

11 635 277 407

11 24,400 15,100 19,900

11 115 4Q 78

11 2,270 671 1,230

8 19.1 9.3 14.6

11 3.9 <1.9 '2.1

11 1,160 775 927

12340000-BLACKFOOT RIVER NEAR BONNER. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1991, 1993-96, 1998-2000

10 2.0 <.2 '.7

7 25.8 15.1 19.9

10 27 16 21

10 20,200 12,400 16,900

10 20 <13 '13

10 683 298 518

7 14.3 9.4 12.5

10 1.0 <.3 '.4

10 73 35 61

12340500-CLARK FORK ABOVE MISSOULA. MONT.

Period of record for fine-grained bed-sediment data: 1997-2000

4 4.2 1.5 2.9

4 30.6 19.0 24.7

4 516 166 296

4 24,300 18,100 21,100

4 63 37 52

4 1.370 480 1.070

4 15.8 11.8 14.3

4 2.9 <3.2 '1.6

4 924 438 651

Median

'<.8

21.4

14

18,500

'8

403

13.0

'<.5

48

3.9

27.2

356

21,700

74

1,130

16.0

'2.1

909

'<1.2

21.6

21

16,900

'12

516

12.7

'<.3

62

3.0

24.6

251

21,100

53

1,230

14.8

"1.3

622

76 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

August 1986 through September 2000 (Continued)

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

Number of Maxi- Constituent Minimum Mean samples mum

12353000--CLARK FORK BELOW MISSOULA. MONT.2

Period of record for fine-grained bed-sediment data: 1986, 1990-2000

12 2.8 1.1 1.8

8 27.6 12.3 21.0

12 293 87 156 

12 21,100 13,400 18,200 

12 58 12 37

12 2,530 446 1,360 

8 14.1 8.9 12.5 

12 2.1 .4 'l.2

12 675 252 415

Median

1.8

21.2

140 

19,000 

36

1,270 

13.1 

'1.2

423

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

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

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

detection level.

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

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

August 1993 through September 2000

[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]

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

12323600--SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for bulk bed-sediment data: 1993-95, 1997-2000

7 20.6 4.2 9.0

7 16.2 9.6 12.7

7 1,660 670 1,050

7 29.300 18,300 21,900

7 300 198 248

7 5,480 504 1,510

7 8.9 6.0 7.0

7 7.4 3.2 4.3

7 5.690 1,720 2,660

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

Period of record for bulk bed-sediment data: 1993, 1995-2000

7 1.7 <.9 'l.O

7 11.8 5.9 9.7

7 111 20 54

7 12.300 7,200 9,730

7 33 <10 '15

7 2,100 209 899

7 9.2 4.8 6.3

7 1.3 <.3 '.7

7 303 93 165

12327700-WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

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

3 1.0 <.8 '.6

3 12.0 9.7 11.2

3 238 203 215

3 12,700 8,980 10,900

3 38 18 30

3 2,650 1,220 2,100

3 8.5 5.7 7.3

3 1.1 <.8 '.8

3 275 146 190

Median

6.7

12.1

902

19,700

248

745

6.5

3.9

2,050

'1.0

9.9

42

9,600 '11

830

5.5

'.8

137

'<.9

11.8

205

10,900

34

2,440

7.8

'.9

148

78 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

August 1993 through September 2000 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

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

12323800--CLARK FORK NEAR GALEN. MONT.

Period of record for bulk bed-sediment data: 1993-2000

8 8.2 <.9

8 23.7 4.2

8 902 223

8 31,300 9,930

8 158 41

8 9.490 900

8 15.2 4.9

8 5.2 .7

8 1,280 417

Mean

'3.7

14.9

455

21,100

80

2.940

8.7

'1.8

730

Median

'3.3

14.9

363

21,500

72

1,710

7.9

'1.6

665

4614151 12450801--CLARK FORK BELOW LOST CREEK. NEAR GALEN. MONT

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Period of record for bulk bed-sediment data: 1996-2000

5 3.3 <.9

5 17.5 9.3

5 763 238

5 21,000 12,600

5 104 41

5 1,740 1.260

5 8.2 4.2

5 2.8 <3.4

5 787 365

'2.3

12.5

432

16,600

71

1.420

6.4

'1.7

545

'2.5

12.0

398

16,000

72

1,390

6.7

'1.7

522

461559112443301--CLARK FORK NEAR RACETRACK. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Period of record for bulk bed-sediment data: 1996-2000

5 6.6 <.9

5 19.1 12.4

5 603 361

5 25,900 16,200

5 87 66

5 1,710 759

5 9.9 5.5

5 2.7 <3.2

5 781 472

4619031 12440701-CLARK FORK AT DEMPSEY CREEK DIVERSION, NEAR

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: 1996-2000

5 9.2 1.5

5 21.1 13.0

5 1,000 244

5 25,400 16,400

5 115 47

5 4.930 825

5 12.8 5.5

5 4.4 <.8

5 1,240 368

12324200--CLARK FORK AT DEER LODGE. MONT.

Period of record tor bulk bed-sediment data: 1993-2000

8 7.8 1.0

8 24.5 12.1

8 906 281

8 25,000 13,200

8 112 45

8 2,530 653

8 12.3 7.7

8 3.9 <.7

8 1,060 456

'2.9

15.0

475

19,600

78

1,390

7.7

'2.0

631

RACETRACK.

3.9

17.7

580

21,600

79

2,090

9.1

'2.2

693

2.9

17.8

485

19,200

76

1,270

9.9

11.8

626

'2.1

14.7

440

18,200

78

1,500

7.3

'1.9

626

MONT.

3.0

17.3

577

20,900

88

1,850

10.0

'2.0

604

2.2

17.9

412

19,000

78

1,040

10.1

'1.6

564

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

August 1993 through September 2000 (Continued)

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

Mean Median

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

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

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

2 .7 <1.2

2 33.2 14.7

2 20 19

2 21,000 15,600

2 18 12

2 420 308

2 15.2 8.6

2 <1.6 <.7

2 86 73

12324680--CLARK FORK AT GOLDCREEK. MONT.

Period of record for bulk bed-sediment data: 1993-2000

8 7.6 1.1

8 33.2 17.6

8 858 243

8 24,900 15,500

8 92 46

8 2,930 554

8 15.9 9.1

8 3.7 <.7

8 1,020 525

12331500--FLINT CREEK NEAR DRUMMOND. MONT.

Period of record fnr hulk bed-sediment data: 1993-2000

8 3.2 <.2

8 13.9 4.9

8 40 16

8 15,700 8,630

8 120 51

8 3,200 1,150

8 8.0 4.5

8 5.8 2.5

8 429 178

12331800--CLARK FORK NEAR DRLMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-2000

8 3.9 <1.6

8 29.5 6.9

8 605 1 14

8 21,800 12,100

8 78 32

8 1,510 711

8 14.2 7.8

8 3.5 .5

8 939 397

'.6

23.9

20

18,300

15

364

11.9

l__

79

3.5

23.1

495

19,700

68

1,440

12.2

12.0

750

'1.2

9.2

25

12,800

79

2,160

5.9

4.2

287

'2.1

19.2

289

16,600

51

1,090

10.7

'1.6

615

-

-

-

-

-

-

__

-

--

2.9

21.2

421

19,100

72

1,220

12.2

'1.6

686

'.9

10.5

22

13,400

80

2.220

5.9

4.0

304

'1.8

18.5

229

16,100

49

1,060

10.1

'1.4

559

80 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

August 1993 through September 2000 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

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

12334510-ROCK CREEK NEAR CLINTON. MONT.

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

7 <1.5 <.2

7 

773

14.3 6.4

7 11,100 5,290

7 <13 <3

7 265 72

7 8.2 3.6

7 <1.6 .1

7 29 10

12334550-CLARK FORK AT TURAH BRIDGE. NEAR BONNER.

Period of record for bulk bed-sediment data: 1993-2000

8 3.3 .4

8 23.8 6.9

8 336 75

8 19,100 9,270

8 67 21

8 1,470 234

8 14.0 6.4

8 2.9 <.3

8 769 271

12340000--BLACKFOOT RIVER NEAR BONNER. MONT.

Mean

l__

9.1

5

8,040

'5

170

5.5

'.3

18

MONT.

'1.7

14.5

189

13,300

38

690

9.2

'1.0

478

Median

kS

8.8

5

7,410

'5

186

5.1

'.3

17

h.6

12.9

184

12,900

36

451

8.6

'.7

504

Period of record for bulk bed-sediment data: 1993-94, 1999-2000

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

4 <1.9 <.2

4 17.7 6.7

4 19 12

4 16,600 10,300

4 11 6

4 650 179

4 9.8 7.5

4 <1.9 <.4

4 58 33

12340500-CLARK FORK ABOVE MISSOULA, MONT.

Period of record for bulk bed-sediment data: 1997-2000

4 3.4 <.8

4 18.2 9.7

4 130 43

4 16,800 11,500

4 30 7

4 810 228

4 11.1 8.2

4 <3.3 <.4

4 387 145

!.5

11.4

16

13,200

9

340

8.6

l

40

'1.2

13.3

93

14,500

21

540

9.7

1 8

283

'<.5

10.6

16

13,100

9

256

8.5

l<.5

34

'.6

12.6

100

14,900

23

562

9.8

'.8

300

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

August 1993 through September 2000 (Continued)

Constituent Number of 

samples

123S3000-CLARK FORK

Maxi- , . Minimum 

mum

Mean Median

BELOW MISSOULA. MONT.2

Period of record for bulk bed-sediment data

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

8

8

8

8

8

8

8

8

8

1.0

12.6

77

11,300

19

444

7.1

<1.9

172

: 1993-2000

<.2

4.4

16

5,830

<10

150

3.5

<3

58

'.5

7.1

39

8,430

'9

336

5.2

'.5

115

U1.2

6.4

31

8,630

'7

366

5.1

'.4

111

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

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

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

reported when all values are below the detection level.

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

82 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

September 2000

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

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

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

constituent was analyzed. Values for single samples are arbitrarily listed in the "Mean" column. Because Hydropsyche insects were 

not sorted to the species level during 1986-89, statistics for stations sampled during those years are based on the results of all 

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

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

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

12323600--SILVER BOW CREEK AT OPPORTUNITY. MONT

Period of record for biological data: 1992, 1994-95, 1997-2000

Brachycentrus spp.

4 12.5 5.8

4 5.9 .7

4 846 235

4 730 335

4 17.9 7.4

4 666 231

4 1.9 <.l

4 888 629

Hydropsyche cockerelli

5 6.3 4.1

5 8.0 1.0

5 462 269

5 1,180 689

5 21.7 19.0

5 718 180

5 2.1 .7

5 898 749

Hydropsyche spp.

_

__

_.

_.

_

__

Hydropsyche tana

6 9.2 4.8

6 11.5 .9

6 456 10.5

6 1,520 857

6 21.0 15.6

6 969 307

6 1.8 .7

6 1.070 760

Mean

9.6

2.1

565

474

11.7

439

'1.2

755

4.9

3.7

365

931

20.3

460

1.4

818

5.0

4.7

352

1,430

36.5

1,040

2.2

1.090

6.8

4.5

236

1,100

18.6

634

1.4

961

Median

10.0

.9

589

416

10.8

430

'1.3

751

4.7

3.1

333

953

20.1

434

1.6

805

-

-

-

-

--

6.9

1.8

298

1,050

18.3

675

1.6

1,020

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1992-2000

Hydropsyche cockerelK

22 2.1 .2

22 1.3 .5

22 96.9 22.4

22 1,240 351

22 5.7 .3

22 2,520 491

22 1.8 .3

22 276 115

.8

.8

44.7

697

3.2

1,050

.8

183

.6

.8

41.8

733

3.0

829

.8

174

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

September 2000 (Continued)

Number of

Constituent composite Maximum Minimum

samples

Mean Median

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1992-2000

Hydropsyche occidentalis

12 1.1 .2

12 1.7 .3

12 46.5 22.8

12 1,050 372

12 4.3 <2.3

12 3,200 1,200

12 1.8 .7

12 202 149

Hydropsyche spp.

4 2.3 .4

4 1.4 .5

4 47.6 34.9

4 773 561

4 5.1 1.9

4 1.100 443

4 1.9 <.4

4 285 141

12323770--WARM SPRINGS CREEK AT WARM SPRINGS.

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

Arctopsvche grandis

3 2.4 1.9

3 2.9 1.4

3 102 95.6

3 1,040 684

3 5.6 <6.3

3 2,280 1.340

3 <7.0 1.8

3 222 180

Hydropsyche 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

Hydropsyche spp.

_

__

_

_.

_

-

12323800-CLARK FORK NEAR GALEN. MONT.

Period of record for biological data: 1987, 1991-2000

Hydropsyche cockerelli

20 2.7 .9

20 3.3 .8

20 181 48.7

20 2.460 816

20 11.7 1.2

20 2,950 1,070

20 3.1 .9

20 299 136

.5

.9

32.2

811

'3.2

2,090

1.2

176

1.1

.8

40.9

680

2.9

725

'.8

195

MONT.

2.2

2.0

98.9

866

'4.4

1.810

'2.5

200

.8

3.2

182

2,010

7.4

2,440

3.2

169

<9.3

1.6

94.8

1,150

<16.7

956

2.0

129

1.5

1.7

102

1.410

7.7

2,080

1.6

219

.4

.9

30.3

805

'3.2

1,810

1.1

177

.9

1.2

40.6

693

4.7

678

'.5

177

2.1

1.8

98.8

872

<8.7

1.800

2.3

197

-

-

-

_

-

-

~

1.5

1.6

100

1,280

7.9

2,140

1.6

222

84 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

September 2000 (Continued)

Number of

Constituent composite Maximum Minimum

samples

Mean Median

12323800-CLARK FORK NEAR GALEN. MONT.-Continued

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1987,

Hydropsyche morosa group

5 3.2

5 4.6

5 185

5 1,890

5 12.4

5 3,960

5 3.6

5 349

Hydropsyche occidentalis

29 1.7

29 6.6

29 106

29 1,920

29 13.5

29 6,170

29 3.5

29 286

Hydropsyche tana

-

-

-

i

1

Hydropsyche spp.

4 3.5

0

4 154

4 1,540

4 13.5

0

0

4 329

1991-2000

2.4

1.8

156

1,360

7.1

2,360

1.9

292

.6

.7

49.2

642

1.6

1,220

.8

168

-

-

-

-

-

-

2.6

-

135

1,190

10.5

-

279

2.5

2.6

173

1,510

8.5

3,500

2.3

309

1.1

1.7

78.1

1,190

6.6

2.470

1.5

200

1.5

1.4

92.9

1,340

9.0

2,160

2.1

206

3.0

148

1,400

12.2

-

308

2.4

2.2

175

1,430

7.9

3,860

2.1

303

1.0

1.4

75.5

1,160

6.3

2,240

1.4

195

-

-

-

3.0

152

1.450

12.4

-

313

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

Period of record for biological data: 1996-2000

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Claassenia sabulosa

-

-

-

-

Hvdropsyche cockerelK

8 2.8

8 2.6

8 147

8 1,900

8 14.8

8 3,160

8 1.9

8 250

-

~

-

-

-

2.2

1.0

48.8

706

12.1

1,230

1.1

151

.3

1.9

70.1

189

1.2

238

.2

245

2.1

2.1

112

1,420

11.6

2,090

1.5

226

-

-

-

-

2.2

2.2

109

1,420

12.1

1,760

1.4

235

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

September 2000 (Continued)

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: 1996-2000

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

Hydropsyche spp.

4 1.8 1.2

4 2.4 .9

4 122 45.1

4 1,410 533

4 20.5 4.1

4 1,980 799

4 2.8 1.4

4 225 143

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

183

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

4615591 12443301-CLARK FORK NEAR RACETRACK. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-2000

Claassenia sabulosa

1

1

..

_

__

__

Hydropsyche cockerelK

1 1.9 1.1

7 2.7 .7

7 109 50.0

7 1,370 846

7 10.5 6.1

7 1.960 646

7 1.4 1.0

7 199 139

Hvdropsvche occidentalis

12 2.2 .7

12 2.6 1.1

12 160 59.5

12 1,880 1,030

12 11.7 4.3

12 3.480 1.090

12 1.9 1.1

12 255 181

Hydropsyche 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

1.7

78.9

1,050

7.9

1,220

1.2

176

1.3

1.9

104

1,500

9.6

2,030

1.3

228

1.2

1.2

84.0

1,170

6.6

1.260

1.2

180

-

-

-

1.4

1.4

82.6

981

7.7

1,050

1.2

179

1.3

1.9

100

1,480

9.9

2,070

1.3

229

-

_

-

86 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

September 2000 (Continued)

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

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

Cadmium 

Chromium 

Copper 

Iron 

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-2000 

Arctopsyche grandis

-

1

1

Hydropsvche cockerelli

4 1.6

4 1.7

4 143

4 1,290

4 8.9

4 1,190

4 1.9

4 180

Hydropsvche occidentalis

15 1.7

15 2.8

15 163

15 1,660

15 13.8

15 3.990

15 2.4

15 292

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

1.0

62.7

831

6.8

487

.9

162

.7

1.2

74.9

1,100

9.7

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

1.0

1.4

90.1

995

8.0

878

1.4

172

1.1

1.9

96.9

1.470

11.5

2,470

1.5

248

1.6

1.8

122

1.340

11.8

892

1.6

202

-

-

-

.8

1.4

77.1

927

8.2

918

1.3

174

1.0

1.9

89.0

1.500

11.4

2,290

1.5

236

-

-

-

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for biological data: 1986-87, 1990-2000

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arctopsyche grandis

2 2.4

2 1.0

2 69.1

2 676

2 <7.8

2 727

2 <1.7

2 178

Hydropsvche cockerelli

21 2.3

21 3.2

21 136

21 3.340

21 18.2

21 1,490

21 2.4

21 391

<4.2

<1.3

34.9

537

3.8

380

<1.3

140

.6

.4

54.7

490

4.3

396

.3

132

'2.2

'.8

52.0

606

'3.8

554

' 

15Q

1.3

1.7

Q3.2

1,160

9.7

790

1.2

185

__

-

-

-

1.3

1.8

87.3

1,050

8.9

700

1.1

184

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

September 2000 (Continued)

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1986-87, 1990-2000

Hydroosvche occidentalis

33 2.7 .8

33 3.6 .6

33 162 49.5

33 2,060 558

33 18.6 3.5

33 2.840 649

33 12.9 1.0

33 329 166

Hvdropsyche spp.

3 2.0 1.2

0

3 222 103

3 2,220 1,110

3 15.0 5.6

0

0

3 203 185

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON.

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

Arctopsyche grandis

10 .5 .2

10 1.6 .6

10 14.0 9.1

10 654 177

10 1.3 .5

10 596 318

10 .6 .4

10 179 113

Claassenia sabulosa

5 .5 .1

5 .9 .7

5 36.1 20.0

5 319 98

5 <1.2 <.4

5 71.0 46.7

5 .7 .5

5 233 191

Hydropsyche cockereltt

_

-

__

j

1

Hydropsyche occidentalis

2 <.7 .3

2 2.3 1.3

2 15.2 15.1

2 1,340 426

2 2.3 <3.7

2 554 434

2 1.1 .8

2 137 110

1.3

1.9

114

1,440

11.1

1,650

1.9

236

1.6

-

145

1,520

8.8

-

195

MONT.

.3

.8

11.4

284

.8

479

.5

149

.3

.8

29.5

174l__

57.8

.6

205

.6

1.6

28.4

478

3.6

399

1.2

123

.3

1.8

15.2

883

2.1

494

1.0

124

1.3

1.9

112

1,430

10.8

1,710

1.5

229

1.6

-

Ill

1,240

5.7

-

197

.3

.8

11.5

235

.8

496

.5

145

.2

.8

31.4

144

'<.6

56.7

.5

202

-

-

-

88 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

September 2000 (Continued)

Constituent

Number of 

composite Maximum Minimum 

samples

Mean Median

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for biological data: 1992-2000

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

Arctopsyche grandis

22 6.6

22 3.3

22 129

22 2,360

22 10.9

22 1,580

22 1.8

22 326

Claassenia sabulosa

17 3.5

17 1.6

17 81.7

17 296

17 1.7

17 184

17 .7

17 351

Hvdropsyche cockerelli

15 2.6

15 4.7

15 188

15 3,250

15 16.2

15 1,670

15 2.3

15 249

Hvdropsyche morosa group

4 1.7

4 1.4

4 72.9

4 1,320

4 6.9

4 1,030

4 1.4

4 190

Hvdropsyche occidentalis

15 1.7

15 3.9

15 156

15 2,720

15 15.7

15 2,210

15 2.5

15 277

1.1

.8

28.8

339

2.3

592

.2

165

.5

.3

33.0

63.0

.5

50.6

.2

166

.6

.7

33.5

589

4.5

538

.6

137

1.1

1.3

43.8

612

2.4

538

.9

137

.7

.4

26.4

466

2.9

530

.8

97

2.7

1.4

56.7

811

4.6

877

.8

217

1.4

.7

55.5

168

1.0

107

.3

258

1.7

2.5

90.9

1,400

8.6

782

1.4

198

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

2.4

1.1

54.9

617

3.7

851

.7

193

1.0

.6

55.6

171

1.0

92.5

.3

258

1.7

2.0

66.6

1,340

6.9

687

1.3

206

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

12331500-FLINT CREEK NEAR DRUMMOND. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1986,

Arctopsyche grandis

37 .8

37 4.7

37 21.7

37 2,460

37 17.5

37 2,480

37 2.7

37 275

1992-2000

.1

.6

8.7

606

3.7

679

.6

141

.4

1.9

15.0

1,370

9.0

1,510

1.4

199

.3

1.7

15.2

1,330

8.4

1,360

1.3

193

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

September 2000 (Continued)

12331500-FLINT CREEK NEAR DRUMMOND. MONT.-Continued

Period of record for biological data: 1986, 1992-2000

Hydropsvche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

9

9

9

9

9

9

9

9

.7

4.0

28.3

3.390

28.4

2,460

2.3

208

.1

.9

9.5

996

3.1

401

.9

85

.4

1.9

17.9

1,960

13.2

1,180

1.9

163

.4

1.8

18.0

1,870

12.9

1,190

2.2

181

Hydropsyche occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

7

7

7

7

7

7

7

7

1

1

2

2

2

2

2

2

2

2

l.l

17.6

27.3

2,990

29.8

4,790

6.9

243

Hydropsyche spp.

-

-

Hydropsyche tana

<1.2

10.3

16.0

1,320

15.3

1,400

3.1

139

.2

.7

15.1

912

5.8

1,400

.8

128

~

--

<.l

.6

5.4

729

5.0

1,180

.5

107

.6

4.5

20.6

1.900

19.4

2,270

3.0

185

<.3

1.4

12.5

1,440

4.5

1,320

1.3

130

l__

5.4

10.7

1,020

10.2

1,290

1.8

123

.6

2.1

18.6

1.870

24.0

1,780

2.4

188

-

-

-

-

-

-

-

-

-

12331800-CLARK FORK NEAR DRUMMOND. MONT.

Period of record for biological data: 1986,

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

27

27

27

27

27

27

27

27

30

30

30

30

30

30

30

30

Arctopsvche erandis

3.8

2.5

89.2

1,660

11.8

2,010

1.9

308

Claassenia sabulosa

2.8

3.3

130

381

2.9

410

1.1

469

1991-2000

.5

.2

18.2

240

2.1

462

.2

142

.3

.3

18.0

76.0

.2

45.9

.1

140

1.6

1.0

37.4

659

5.0

900

.7

197

1.3

.8

65.1

160

1.0

162

.3

270

1.5

1.0

32.0

650

4.3

754

.7

190

1.3

.6

56.9

133

.9

148

.2

251

90 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

September 2000 (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, 1991-2000

Hydropsyche cockeretti

22 2.3 .7

22 3.5 .4

22 156 37.2 

22 2.500 506

22 15.0 5.1

22 1,680 549 

22 2.0 .5

22 248 134

Hydropsyche 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

Hydropsvche occidentalis

15 2.0 .7

15 8.1 .4

15 118 13.3 

15 2,060 424

15 13.5 2.9

15 2,920 619 

15 2.4 .5

15 293 157

Hydropsyche spp.

1

0

1 

i

1

0 

0

1

12334510-ROCK CREEK NEAR CLINTON, MONT.

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

Arctopsvche grandis

32 .4 .06

32 2.9 .5

32 15.7 4.7 

32 991 191

32 <2.9 .1

32 454 113 

32 1.6 .2

32 189 84

Claassenia sabulosa

16 .3 .05

16 1.8 .4

16 40.7 18.1 

16 129 49.8

16 1.0 .1

16 76.3 15.7 

16 .9 .1

16 264 164

1.4

1.9

70.1 

1,310

9.4

924 

1.3

201

1.2

2.3

55.2 

1,570

8.9

1,610 

1.5

239

1.2

2.4

57.0 

1,283

9.1

1,500 

1.5

226

2.6

85.0 

940

9.1

260

.2

1.2

8.6 

517

'.4

249 

.8

127

.2

.8

29.8 

90.7

.3

35.0 

.3

205

1.4

1.7

54.5 

1,280

9.1

784 

1.2

198

1.2

2.2

55.8 

1,600

9.0

1,620 

1.5

240

1.2

2.2

56.3 

1,420

9.1

1,220 

1.7

223

-

.2

1.0

8.3 

464

U

226 

.9

124

.1

.6

30.0 

93.1

.3

33.6 

.3

207

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

September 2000 (Continued)

12334510--ROCK CREEK NEAR CLINTON. MONT.-Continued

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

Hydropsyche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

3 <.2

3 1.0

3 13.1

3 609

3 <1.1

3 258

3 .9

3 99

Hydropsyche occidentalis

4 <1.0

4 2.4

4 17.6

4 752

4 6.0

4 268

4 1.7

4 144

Hydropsyche spp.

3 .3

3 2.1

3 16.2

3 1,140

3 <3.1

3 462

3 1.3

3 135

<.2

.9

6.0

485

<1.1

192

.4

82

<.3

.9

9.6

520

1.2

169

.6

99

<.5

1.1

11.6

837

<1.8

299

.8

117

12334550-CLARK FORK AT TURAH BRIDGE. NEAR BONNER.

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.

Arctopsvche grandis

36 2.7

36 4.1

36 125

36 2,870

36 13.2

36 893

36 2.6

36 276

Claassenia sabulosa

24 2.5

24 2.0

24 79.2

24 181

24 1.6

24 139

24 .6

24 283

Hydropsyche cockerelli

24 1.7

24 8.0

24 118

24 2,530

24 12.1

24 788

24 2.6

24 228

1991-2000

.6

.6

20.1

420

2.1

351

.4

152

.3

.4

38.3

58.6

.2

37.2

.1

144

.5

1.0

26.4

688

2.2

426

.6

148

' 

.9

8.6

530

'-

219

.6

89

' 

1.6

12.0

642

3.0

228

1.2

121

'.2

1.6

14.3

1,000

l

399

1.1

126

MONT.

1.4

1.8

42.3

1,070

4.8

634

1.2

206

1.2

.7

56.7

103

.6

76.4

.2

221

.9

2.2

51.0

1,280

5.5

597

1.3

188

<.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

1.4

1.7

35.8

942

4.0

637

1.0

202

.9

.6

53.9

101

.6

68.5

.1

226

.8

1.8

43.9

1,100

5.2

570

1.2

184

92 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

September 2000 (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, 1991-2000

Hydropsyche 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

-

-

-

-

Hvdropsyche occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc >

18

18

18

18

18

18

18

18

1

1

1.8

3.2

102

2,310

14.2

1,600

3.2

416

Hydropsyche spp.

-

-

-

.3

.6

34.1

472

3.0

454

.6

145

-

-

--

.9

1.9

51.1

1.220

6.7

812

1.2

207

1.3

2.4

84.1

1,800

<7.8

537

1.3

171

.9

1.8

43.7

1,090

5.7

688

1.0

188

-

-

-

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

Arctopsyche grandis

A

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

<.1

.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

Hydropsyche 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 

September 2000 (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

Hydropsyche spp.

1

1

1

1

1

1

\

\

12340500-CLARK FORK ABOVE M1SSOULA. MONT.

Period of record for biological data: 1997-2000

Arctopsyche grandis

n 1.8 .5

12 3.0 1.3

12 77.6 22.3

12 2,340 708

12 6.8 1.2

12 1,210 476

12 2.0 .7

12 235 155

Claassenia sabulosa

6 2.0 .2

6 1.1 .4

6 71.7 37.8

6 402 95.0

6 3.1 .5

6 683 75.2

6 <1.3 <.3

6 363 191

Hydropsyche cockeretti

8 1.3 .4

8 4.1 1.9

8 96.1 29.9

8 3,590 1,400

8 6.3 4.2

8 1.250 781

8 2.4 1.4

8 226 156

Hydropsyche 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, 1990-2000

Arctopsvche grandis

22 1.5 .2

22 2.7 .5

22 38.0 9.4

22 1.500 343

22 3.2 .9

22 1,090 511

22 1.6 .4

22 217 106

. .6

1.6

13.9

1,140

2.9

525

2.8

132

.9

1.7

36.1

1,180

3.4

815

1.2

190

.9

.8

51.1

225

11.2

230

'.4

287

.9

2.9

57.8

2,200

5.4

996

1.8

192

.7

2.7

48.5

1,970

5.7

1,810

2.0

218

.7

1.4

21.5

785

1.8

722

.9

155

-

-

-

-

-

-

.8

1.7

32.8

1,100

3.3

846

1.3

187

.8

.8

47.1

218

'1.0

123

'<.4

290

1.0

3.2

45.9

2,060

5.5

967

1.8

192

.7

2.9

48.2

2,110

5.5

1.810

2.0

221

.7

1.4

21.2

783

1.8

712

.9

150

94 Water-quality, bed-sediment, and biological data (October 1999 through September 2000) and statistical summaries of data for streams in the 

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

September 2000 (Continued)

Number of 

Constituent composite 

samples

Maximum

12353000--CLARK FORK BELOW MISSOULA.

Minimum Mean Median

MONT.2-Continued

Period of record for biological data: 1986, 1990-2000

Claassenia sabulosa

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

34

34

34

34

34

34

34

34

1.3

1.2

66.4

240

1.3

168

.3

286

.1

.05

31.1

66.6

.1

48.9

.1

146

.5

.5

47.3

108

.4

103

.2

214

.4

.5

46.4

98

.3

101

.2

204

Hydropsyche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

30

30

30

30

30

30

30

30

1.1

3.4

45.7

2,000

3.6

1,210

1.7

172

.2

.8

12.4

584

1.2

353

.5

77.4

.5

1.9

29.6

1,250

2.2

749

1.2

145

.6

1.9

32.0

1,270

2.3

664

1.3

154

Hydropsvche occidentals

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

15

15

15

15

15

15

15

15

1.1

3.5

38.2

1,420

4.2

1,460

2.2

193

.2

.2

16.0

482

.7

575

.5

112

.5

1.4

24.7

938

2.1

874

1.0

144

.4

1.5

22.2

907

1.9

834

.9

149

Hvdropsvche spp.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

1

1

1

1

1

1

1

1

-

-

-

--

-

-

-

--

.5

.8

20.8

894

1.1

756

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

ft U.S. GOVERNMENT PRINTING OFFICE: 2001 773-525 / 61000 Region No. 8