Water-Quality, Bed-Sediment, and Biological Data 

(October 2002 through September 2003) and 

Statistical Summaries of Data for Streams 

in the Upper Clark Fork Basin, Montana

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

In cooperation with the

U.S. Environmental Protection Agency

Open-File Report 2004-1340

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

U.S. Geological Survey, Reston, Virginia: 2004

For sale by U.S. Geological Survey, Information Services 

Box 25286, Denver Federal Center 

Denver, CO 80225

For additional information write to:

District Chief 

U.S. Geological Survey 

3162 Bozeman Avenue 

Helena, Montana 59601

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

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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.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.
Ill

CONTENTS

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................................................................................................ 9

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

Biological data............................................................................................. 10

Methods............................................................................................. 11

Results............................................................................................... 11

Quality assurance.................................................................................... 11

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

References cited........................................................................................... 12

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

FIGURE

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

TABLES

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 2002 through

September 2003.................................................................................. 16

5-7. Daily streamflow and suspended-sediment data, October 2002 through September 2003, for:

5. Clark Fork at Deer Lodge, Montana........................................................... 36

6. Clark ForkatTurah Bridge, near Bonner, Montana............................................40

7. Clark Fork above Missoula, Montana......................................................... 44

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

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

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

samples, upper Clark Fork basin, Montana........................................................ 50
IV

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

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

11. Recovery efficiency for trace-element analyses of laboratory-spiked deionized-water blanks..... 52

12. Recovery efficiencyfortrace-elementanalyses of laboratory-spiked stream samples, upper

Clark Fork basin, Montana........................................................................ 53

13. Chemical analyses of field blanks for water samples.............................................. 54

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

September2003.................................................................................. 55

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

September 2003.................................................................................. 56

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

sediment......................................................................................... 57

17. Trace-element analyses of procedural blanks for bed sediment.................................. 58

18. Trace-element analyses of biota, upper Clark Fork basin, Montana, September 2003.............. 59

19. Recovery efficiency for trace-element analyses of standard reference material for biota.......... 61

20. Trace-element analyses of procedural blanks for biota........................................... 62

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

1985 through September 2003.................................................................... 63

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

August 1986 through September 2003............................................................. 81

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

August 1993 through September 2003............................................................. 86

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

through September 2003.......................................................................... 91
Conversion Factors, Datum, Abbreviated WaterQuality Units, and Acronyms

Multiply

cubic foot per second (ft3/s)

foot (ft)

gallon (gal)

gallon (gal)

inch (in.)

inch (in.)

mile (mi)

ounce (oz)

part per million

i-\

square mile (mi )

ton per day (ton/d)

By

0.02832

0.3048

3.785

3,785

25.4

25,400

1.609

28.35

1

2.59

907.2

To obtain

cubic meter per second (m /s)

meter (m)

liter (L)

milliliter (mL)

millimeter (mm)

micrometer (|jin)

kilometer

gram (g)

microgram per gram (^ig/g)

square kilometer

kilogram per day

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F = (1.8x°C) + 32

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 

(NGVD 29). Horizontal coordinate information is referenced to the North American Datum of 1927 

(NAD 27).

Abbreviated water-quality units used in this report:

mcrograms per gram

micrograms per liter 

ng/ml_ micrograms per milliliter 

urn micrometer

^iS/cm microsiemens per centimeter at 25 degrees Celsius 

mg/L milligrams per liter

Water-year definition:

A water year is the 12-month period from October 1 through September 30. It is designated by 

the calendar year in which it ends.

Acronyms used in the report:

ICAPES inductively coupled argon plasma emission spectroscopy RSD relative standard deviation 

LRL laboratory reporting level SRM standard reference material 

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

NWQL USGS National Water Quality Laboratory, Denver, Colo.
Water-Quality, Bed-Sediment, and Biological Data 

(October 2002 through September 2003) and 

Statistical Summaries of Data for Streams 

in the Upper Clark Fork Basin, Montana

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

Abstract

Water, bed sediment, and biota were sampled in streams 

from Butte to below Missoula as part of a program to characterize aquatic resources in the upper Clark Fork basin of western 

Montana. Sampling stations were located on the Clark Fork, 

five major tributaries, and four smaller tributaries. Water-quality data were obtained periodically at 18 stations during October 

2002 through September 2003 (water year 2003). Data for 15 

bed-sediment and 15 biological stations were obtained in September 2003. 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. Quality-assurance 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 since 1985 for each 

station.

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, 

five major tributaries enter: Warm Springs Creek, Little Blackfoot River, Flint Creek, Rock Creek, and Blackfoot River. PrinSJ

cipal surface-water uses in the 6,000-mi Clark Fork basin 

above Missoula include irrigation, stock watering, light industry, hydroelectric power generation, and habitat for trout fisheries. Current land uses primarily are cattle production, logging, 

mining, and recreation. Large-scale mining and smelting were 

prevalent land uses in the upper basin for more than one hundred years, but are now largely discontinued.

Deposits of copper, gold, silver, and lead ores were 

extensively mined, milled, and smelted in the drainages of 

Silver Bow and Warm Springs Creeks from about 1870 to 1980. 

Moderate- and small-scale mining also occurred in the basins of 

most of the major tributaries to the upper Clark Fork. Tailings 

derived from mineral processing commonly contain large 

quantities of trace elements such as arsenic, cadmium, copper, 

lead, and zinc. Tailings have been eroded, mixed with stream 

sediment, transported downstream, and deposited in stream 

channels, on flood plains, and in the Warm Springs Ponds and 

Milltown Reservoir. The widely dispersed tailings continue to 

be re-eroded, transported, and redeposited along the stream 

channel and flood plain, especially during high flows. The 

occurrence of elevated trace-element concentrations in water 

and bed sediment can pose a potential risk to aquatic biota and 

human health.

Concern about the potential toxicity of trace elements to 

aquatic biota and human health has resulted in a comprehensive 

effort by State, Federal, and private entities to characterize the 

aquatic resources in the upper Clark Fork basin to guide and 

monitor remedial cleanup activities. A long-term data base was 

considered necessary to detect trends over time in order to evaluate the effectiveness of remediation. Water-quality data have 

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

selected sites in the upper Clark Fork basin since 1985 (Lambing, 1987, 1988, 1989, 1990, 1991; Lambing and others, 1994, 

1995; and Dodge and others, 1996, 1997, 1998, 1999, 2000, 

2001, 2002, 2003). Trace-element data for bed sediment and 

biota (aquatic benthic insects) have been collected intermittently since 1986 at selected sites as part of studies on bed-sediment contamination and bioaccumulation of metals conducted 

by the USGS National Research Program (Axtmann and 

Luoma, 1991; Cain and others, 1992, 1995; Axtmann and others, 1997; Hornberger and others, 1997). In March 1993, an 

expanded sampling program for water, bed sediment, and biota

'U.S. Geological Survey, Menlo Park, Calif.
2 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) and Statistical Summaries of Data for Streams 

in the Upper Clark Fork Basin, Montana

12353000

Missoula

Base modified from U.S. Geological 

Survey, State base map, 1:1,000,000, 

1966. North American Datum of 1927 

(NAD 27)

461903112440701

461559112443301

461415112450801

Galen

LavMj

Warm Springs

ft*,,- 12323770

12323250

12323230

EXPLANATION

12324200 STATION NUMBER 

461903112440701 MISCELLANEOUS SITE NUMBER 

STREAMFLOW STATION TYPE 

A Continuous record 

A Periodic measurement

WATER QUALITY, BED SEDIMENT, 

AND BIOTA STATION TYPE

XJ Periodic water quality

V- Daily suspended sediment

^J~ Once-annual bed sediment

~T7 Once-annual biota

46°

Figure 1. Location of study area.
Sampling Locations And Types Of Data 3

was implemented by the USGS in cooperation with the U.S. 

Environmental Protection Agency to provide systematic, longterm monitoring to better quantify the seasonal and annual variability in selected constituents.

The purpose of this report is to present water-quality data 

for 18 stations and trace-element data for 15 bed-sediment and 

15 biological stations in the upper Clark Fork basin collected 

from October 2002 through September 2003 (water year 2003). 

Quality-assurance data are presented for water-quality, bedsediment, and biota samples. Statistical summaries also are 

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

collected since 1985.

Sampling Locations And Types Of Data

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. At 14 sites, samples were 

collected 8 times per year on a schedule designed to describe 

seasonal and hydrologic variability. At four tributary sites, 

samples were collected only twice during the water year 

because of termination, and then reinstatement, of those sites in 

the sampling program.

Sampling stations in the upper Clark Fork basin are located 

on the Clark Fork mainstem, five major tributaries (Warm 

Springs Creek at Warm Springs, Little Blackfoot River near 

Garrison, Flint Creek near Drummond, Rock Creek near Clinton, and Blackfoot River near Bonner), and four smaller tributaries (Blacktail Creek at Harrison Avenue, Mill Creek at 

Opportunity, Willow Creek at Opportunity, and Lost Creek 

near Galen) from Butte to below Missoula (fig. 1). The stations, 

types of data collected, and period of record for each data type 

are listed in table 1. Mainstem sampling sites were selected to 

divide the upper Clark Fork into reaches of relatively uniform 

length, with each reach encompassing either a major tributary or 

depositional environment (Warm Springs Ponds and Milltown 

Reservoir). Major tributaries were sampled to describe waterquality characteristics of important hydrologic sources in the 

upper basin and to provide reference comparisons to the mainstem for bed sediment and biota. In 2003, three additional tributaries were included for continuous streamflow and periodic 

water-quality sampling Mill Creek, Willow Creek, and Lost 

Creek. These tributaries drain the area near Anaconda and were 

added to gain more resolution on sources of metals entering the 

Clark Fork in an area of historical metal-processing activities. 

Water-quality data were obtained periodically at 18 stations; 

daily suspended-sediment data were obtained for part of the 

year at 3 of these stations. Trace-element data for 15 bed-sediment and 15 biological stations were obtained once-annually. 

Continuous streamflow data were collected at 18 stations.

A list of properties measured onsite and constituents analyzed in samples of water, bed sediment, and biota is given in 

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

as well as associated quality-assurance data for water year 2003 

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 2003 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

Methods

Cross-sectional water samples were collected from multiple verticals across the stream using depth- and width-integration methods described by Ward and Harr (1990) and Edwards 

and Glysson (1999). These methods provide a vertically and 

laterally discharge-weighted composite sample that is representative of the entire flow passing through the cross section of a 

stream. Sampling equipment consisted of standard USGS 

depth-integrating suspended-sediment samplers (DH-48, DH81, and D-74TM), which were either constructed of plastic or 

coated with a non-metallic epoxy paint, and equipped with 

nylon or Teflon nozzles.

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). 

Onsite measurements of specific conductance, pH, and water 

temperature were made during collection of periodic waterquality samples. Onsite sample processing, including filtration 

and preservation, was performed according to procedures 

described by Ward and Harr (1990), Horowitz and others 

(1994), and the USGS (variously dated) National Field Manual 

for the Collection of Water-Quality Data.

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 filtered (0.45-um pore size) and unfiltered recoverable concentrations. Calcium and magnesium also were determined in 

filtered samples to enable calculation of hardness. The terms 

"filtered" and "unfiltered recoverable" replace the terms "dissolved" and "total recoverable," respectively, which were used 

in the past. Filtered concentrations of arsenic, cadmium, copper, lead, manganese, and zinc were analyzed by inductively 

coupled plasma-mass spectrometry (Faires, 1993; Garbarino, 

1999). Filtered concentrations of calcium, magnesium, and iron 

were analyzed by inductively coupled plasma-atomic emission 

spectrometry (Fishman, 1993). Unfiltered-recoverable traceelement concentrations were determined from unfiltered
Table 1. Type and period of data collection at sampling stations in the upper Clark Fork basin, Montana

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

Station number 

(fig. 1)

12323230

12323250

12323600

12323700

12323720

12323750

12323770

12323800

12323850

461415112450801

461559112443301

461903112440701

12324200

12324590

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

Station name

Blacktail Creek at Harrison Avenue, at 

Butte

Silver Bow Creek below Blacktail Creek, 

at Butte

Silver Bow Creek at Opportunity

Mill Creek at Opportunity

Willow Creek at Opportunity

Silver Bow Creek at Warm Springs

Warm Springs Creek at Warm Springs

Clark Fork near Galen

Lost Creek near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek diversion, 

near Racetrack

Clark Fork at Deer Lodge

Little Blackfoot River near Garrison

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula4

Continuousrecord 

streamflow

 

10/83-P

07/88-P

04/03-P

04/03-P

03/72-09/79, 

04/93-P

10/83-P

07/88-P

04/03-P

-

~

 

10/78-P

10/72-P

10/77-P

08/90-04/03, 

08/03-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, 

12/96-08/03

03/93-08/95, 

12/96-P

03/93-08/95, 

12/96-P

03/03-P

03/03-P

03/93-P

03/93-P

07/88-P

03/03-P

--

-

03/85-P

03/85-P

03/93-P

03/85-P

03/93-P

03/85-P

03/85-P

03/85-P

07/86-P3

03/85-09/95

Daily suspended 

sediment

 

"

03/93-09/95

-

-

04/93-09/95

 

-

-

-

~

03/85-08/86, 

04/87-03/03, 

08/03-P

"

-

~

~~

 

03/85-03/03, 

08/03-P

07/86-04/87, 

06/88-09/95

07/86-04/87, 

06/88-01/96, 

03/96-03/03, 

08/03-P

 

Fine-grained 

bed sediment2

 

~

07/92-P

-

--

07/92-P

08/95, 08/97, 

08/99, 08/02

08/87, 

08/9 1-P

-

08/96-P

08/96-P

08/96-P

08/86, 08/87, 

08/90-P

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

08/98,08/01

07/92-P

08/86, 08/89, 

07/92-P

08/86, 08/87, 

08/9 1-P

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

08/9 1-99, 08/0 1-P

08/86, 

08/9 1-P

08/86, 08/87, 

08/91, 

08/93-96,08/98-01, 

09/03

08/97-P

08/86, 

08/90-P

Bulk bed sediment2

~

08/93-08/95, 

08/97-P

-

-

08/93, 

08/95-P

08/95, 08/97, 

08/99, 08/02

08/93-P

-

08/96-P

08/96-P

08/96-P

08/93-P

08/94,08/98,08/01

08/93-P

08/93-P

08/93-P

08/93-99, 08/0 1-P

08/93-P

08/93,08/94,08/99-01, 

09/03

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, 

08/02

08/87, 

08/9 1-P

-

08/96-P

08/96-P

08/96-P

08/86, 08/87, 

08/90-P

08/87, 08/94 

08/98,08/01

07/92-P

08/86, 

07/92-P

08/86, 

08/9 1-P

08/87, 

08/91-99, 08/01-P

08/86, 

08/9 1-P

08/86, 08/87, 

08/91,08/93, 

08/96,08/98,09/00, 

09/03

08/97-P

08/86, 

08/90-P

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

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

Laboratory analyses of trace elements.

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

Bed sediment and biota sampled about 30 miles downstream from streamflow-gaging station to conform to previous sampling location.

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Water-Quality Data

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 (calculated)

Calcium

Magnesium

Arsenic

Cadmium

Copper

Iron

Lead

Manganese

Zinc

Suspended sediment

Bed sediment

Constituent

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Biota

Constituent

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

samples that were first digested with dilute hydrochloric acid 

(Hoffman and others, 1996) and then analyzed for arsenic by 

graphite furnace-atomic absorption spectrometry (Jones and 

Garbarino, 1999) and for cadmium, copper, iron, lead, manganese, and zinc by inductively coupled plasma-mass spectrometry (Garbarino and Struzeski, 1998).

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 mass finer than 0.062-mm diameter (silt size 

and smaller) by the USGS sediment laboratory in Helena, 

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

Lambing and Dodge (1993).

At the three daily suspended-sediment stations (table 1), 

suspended-sediment samples were collected 2 to 9 times per 

week for only part of the year (October through March, and 

August through September) as the result of program modifications. These samples were collected by local contract observers 

using the depth-integration method at a single vertical near midstream. The samples were analyzed for suspended-sediment 

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

described by Porterfield (1972). Five supplemental water-quality and suspended-sediment samples were collected at Clark 

Fork at Turah Bridge, near Bonner (12334550) and Clark Fork 

above Missoula (12340500), from May 29-June 2. These samples were collected to better define variability in trace-element 

and suspended-sediment concentrations above and below Milltown Reservoir during high flow.

Results

Water-quality data for samples collected periodically during water year 2003 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 available daily suspended-sediment 

data for water year 2003 at the three daily suspended-sediment 

stations are given in tables 5 through 7. Monthly descriptive 

statistics for each parameter are provided along with totals for 

the annual discharge of water and suspended sediment.

Quality Assurance

Quality-assurance procedures used for the collection and 

field processing of water-quality samples are described by 

Ward and Harr (1990), Knapton and Nimick (1991), Horowitz 

and others (1994), Edwards and Glysson (1999), and the USGS 

(variously dated) National Field Manual for the Collection of 

Water-Quality Data. 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 per-
6 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) and Statistical Summaries of Data for Streams 

in the Upper Clark Fork Basin, Montana

formed systematically to provide quality control of analytical 

procedures (Pritt and Raese, 1995). These internal practices 

include analyses of quality-control samples such as calibration 

standards, standard reference water samples, replicate samples, 

deionized-water blanks, or spiked samples at a proportion 

equivalent to at least 10 percent of the sample load. The 

NWQL participates in a blind-sample program where standard 

reference water samples prepared by the USGS Branch of Quality Systems are routinely inserted into the sample line for each 

analytical method at a frequency proportional to the sample 

load. The laboratory also participates in external evaluation 

studies twice-yearly with the U.S. Environmental Protection 

Agency, the Canadian Center for Inland Water, and the USGS 

Branch of Quality Systems to assess analytical performance.

Replicate data can be obtained in different ways to provide 

an assessment of precision (reproducibility) of analytical 

results. Replicate samples are two or more samples considered 

to be essentially identical in composition. Replicate samples 

can be obtained in the field (field replicate) by either repeating 

the collection process to obtain two or more independent composite samples, or by splitting a single composite sample into 

two or more subsamples. The individual replicate samples are 

then analyzed separately. Likewise, a single sample can be analyzed two or more times in the laboratory to obtain a measure of 

analytical variability (laboratory replicate).

Precision of analytical results for field replicates is 

affected by numerous sources of variability within the field and 

laboratory environments, including sample collection, sample 

processing, and sample analysis. To provide data on precision 

for samples exposed to all sources of variability, replicate 

stream samples for chemical analysis were obtained in the field 

by splitting a composite stream sample, and replicate stream 

samples for suspended-sediment analysis were obtained in the 

field by concurrently collecting two independent cross-sectional samples. Analyses of these field replicates indicate the 

reproducibility of environmental data that are affected by the 

combined variability potentially introduced by field and laboratory processes.

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

randomly in the laboratory from the group of samples comprising each analytical run. A separate analysis of the sample was 

made at the beginning and end of each analytical run to provide 

information on the reproducibility of laboratory analytical 

results independent of possible variability caused by field collection and processing of samples.

Spiked samples are used to evaluate bias, which measures 

the ability of an analytical method to accurately quantify 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 biased (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 traceelement 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 traceelement 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 chainof-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 monitoring program are 

directly applicable to the analytical results for stream samples 

reported herein.

Data-quality objectives (table 3) were established for 

water-quality data as part of the study plan for the expanded 

long-term monitoring program that was initiated in 1993. The 

objectives identify analytical requirements of detectability and 

serve as a guide for identifying questionable data by establishing acceptable limits for precision and bias of laboratory results. 

Comparisons of quality-control data to data-quality objectives 

are used to evaluate whether sampling and analytical procedures are producing environmentally representative data in a 

consistent manner. Data that did not meet the objectives were 

evaluated for acceptability, and corrective action was taken, 

when appropriate.

During water year 1999, the NWQL began implementation of a new, statistically based convention for establishing 

reporting levels and for reporting low-concentration data (Childress and others, 1999). Quality-control data are collected on a 

continuing basis to determine long-term method detection levels (LT-MDLs) and laboratory reporting levels (LRLs). These 

values are re-evaluated each year and, consequently, may 

change from year to year. The methods are designed to limit the 

possible occurrence of a false positive or false negative error to 

1 percent or less. Accordingly, concentrations are reported as 

less than the LRL for samples in which the analyte was either 

not detected or did not pass identification criteria. Analytes that 

are detected at concentrations between the LT-MDL and LRL 

and that pass identification criteria are estimated. Estimated 

concentrations are noted with a remark code of "E." These data
Water-Quality 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):

S =

where 

S 

d 

k

= standard deviation of the difference in concentration between replicate analyses,

= difference in concentration between each pair of 

replicate analyses, and

= number of pairs of replicate analyses.

A/ 2k (1)

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):

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

[The terms "filtered" and "unfiltered recoverable" replace the former terms "dissolved" and "total recoverable," respectively. Abbreviations: 

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

Data-quality objectives

Detectability

Constituent

Calcium, filtered

Magnesium, filtered

Arsenic, unfiltered recoverable

Arsenic, filtered

Cadmium, unfiltered recoverable

Cadmium, filtered

Copper, unfiltered recoverable

Copper, filtered

Iron, unfiltered recoverable

Iron, filtered

Lead, unfiltered recoverable

Lead, filtered

Manganese, unfiltered recoverable

Manganese, filtered

Zinc, unfiltered recoverable

Zinc, filtered

Sediment, suspended

Sediment, suspended, percent finer than 0.062 mm

Precision

Maximum relative 

Laboratory standard deviation of 

reporting laboratory replicate 

level 1 analyses, 

in percent

0.01

.008

2

.3

.04

.04

.6

.2

6-20

8-10

.06

.08

.22

.2

2

1

1

1

mg/L

mg/L

Hg/L

fig/L

Hg/L

|ig/L

lig/L

Hg/L

M,g/L

M,g/L

M,g/L

u,g/L

Hg/L

Hg/L

(ig/L

M-g/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

-

-

^or those constituents showing a range of values, the laboratory reporting level changed during water year 2003.
8 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) and Statistical Summaries of Data for Streams

in the Upper Clark Fork Basin, Montana

RSD = x 100 (2)

where

RSD = relative standard deviation,

S = standard deviation, and

x = mean of all replicate concentrations.

Paired analyses of field replicates are presented in table 8. 

The precision estimated for each constituent based on these 

paired results, which include both field and laboratory sources 

of variability, is reported in table 9. Statistics for precision of 

field-replicate analyses were based on the values reported in 

table 8, which are rounded to standard USGS reporting levels 

for the particular constituent and its analytical method (Timme, 

1994).

Data-quality objectives for precision are not directly applicable to field replicates because of the inability to determine 

whether the variability results from field sample collection and 

processing, or laboratory handling and analysis. However, a 

statistical calculation of precision for the field replicates is provided in table 9 to illustrate overall reproducibility of environmental data that incorporates both field and laboratory sources 

of variability. The data-quality objective used to evaluate precision of results for field replicates was a maximum relative standard deviation of 20 percent (table 3). Precision estimates for 

the field replicate analysis were within the 20-percent relative 

standard deviation limit for all constituents.

Analytical precision for chemical constituents based on 

replicate laboratory analyses of individual samples, which 

includes only laboratory sources of variability, is reported in 

table 10. Statistics for analytical precision of laboratoryreplicate analyses are based on unrounded values stored in 

laboratory data files. The data-quality objective for analytical 

precision of laboratory-replicate analyses was 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.

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 particular trace element until recoveries were improved to 

the extent possible. Results of recovery efficiency for individual trace elements in spiked deionized-water blanks and spiked 

stream samples are presented in tables 11 and 12, respectively. 

The mean spike recovery for deionized-water samples spiked 

with trace elements (table 11) ranged from 87.9 to 101.6 percent. The mean spike recovery for spiked stream samples (table 

12) ranged from 91.6 to 108.6 percent. The 95-percent confidence intervals (Taylor, 1987) for the mean of spike recovery 

for each constituent analyzed in stream samples (table 12) did 

not exceed a 25-percent deviation from an expected 100-percent recovery.

High or low bias is indicated if the confidence interval 

does not include 100 percent recovery. All laboratory-spiked 

deionized-water blank samples (table 11) had confidence intervals for percent recovery that included 100 percent, except filtered iron (87.4-98.8) and unfiltered recoverable lead (93.9- 

98.1) percent. All laboratory-spiked stream samples (table 12) 

had confidence intervals for percent recovery that included 100 

percent, except unfiltered recoverable copper (89.7-93.5), unfiltered recoverable lead (93.7-99.9), and unfiltered recoverable 

zinc (87.5-98.5) percent. Because the mean spike recoveries for 

all constituents met data-quality objectives, no adjustments 

were made to analytical results for stream samples on the basis 

of spike recoveries.

Analytical results for field blanks are presented in table 13. 

A field blank with constituent concentrations equal to or less 

than the LRL for the analytical method indicates that the entire 

process of sample collection, field processing, and laboratory 

analysis is presumably free of significant contamination. If 

detectable concentrations in field blanks were equal to or 

greater than twice the LRL (typical measurement precision at 

the analytical 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 exceeded twice the 

LRL in field blanks from two consecutive field trips, blank samples were collected from individual components of the processing sequence and were submitted for analysis in order to identify the source of contamination.

Trace-element concentrations in field blanks were almost 

always less than the LRL. Minor detections equal to the LRL 

were noted for filtered copper and unfiltered recoverable zinc.

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

spike concentration

(3)
Bed-Sediment Data 9

No adjustments were made to water-quality sample results 

based on these minor detections because neither constituent 

exceeded the LRL in consecutive blank samples.

One major exceedance occurred for filtered cadmium 

(0.34 ^ig/L) following an annual equipment blank collected 

through a D-74 TM sampler. This sample was collected about

3 weeks prior to the associated sampling run, and the collected 

bottles remained in the Montana District office until they could 

be submitted with the environmental samples. Also, all subsequent blank samples collected through this sampler had filtered 

cadmium concentration below the LRL, and all environmental 

samples collected immediately following this blank had filtered 

cadmium levels of 0.04 ^ig/L or less. This random exceedance 

is not traceable to any systematic processing source, and concentrations in environmental samples apparently were not 

affected; therefore, no adjustments to environmental data were 

warranted.

A minor, but more persistent level of potential bias 

occurred for filtered zinc in blank samples collected from 

February through the first sampling trip in June, with filtered 

zinc concentrations ranging from 2 to 4 [ig/L. In response to 

this trend, an equipment blank was prepared along with 

incremental blank samples collected after each step in the 

processing sequence. Analytical results from this qualityassurance assessment indicated that a small amount of 

contamination was being introduced from the tubing used in the 

filtration process. After the tubing was replaced, no further 

contamination was noted in blank samples. Filtered zinc 

concentrations for environmental samples were decreased by 2-

4 ng/L for all samples collected during the affected period 

based on the magnitude of the filtered zinc concentration in the 

blank sample collected for that specific sampling trip.

Bed-Sediment Data

Bed-sediment data consist of analyses of trace-element 

concentrations in the fine-grained and bulk (fine- plus coarsegrained) fractions of the bed-sediment sample. Bed-sediment 

samples were collected once-annually during low, stable flow 

conditions and the same season (typically August) as previous 

samples to facilitate data comparisons among years.

Methods

Bed-sediment samples were collected in September 2003 

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

Survey, written commun., 1994). Samples were collected from 

the surfaces of streambed deposits in low-velocity areas near 

the edge of the stream using an acid-washed polypropylene 

scoop. Whenever possible, samples were collected from both 

sides of the stream. Three composite samples of fine-grained 

bed sediment and one composite sample of bulk bed sediment 

were collected at each site.

Individual samples of fine-grained bed sediment were collected by scooping material from the surfaces of three to five 

randomly selected deposits along pool or low-velocity areas. 

The three to five individual samples were combined to form a 

single composite sample. This collection process was repeated 

three 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 of three to five 

randomly selected deposits. The individual unsieved samples 

were composited into an acid-washed polyethylene bottle to 

form a single composite sample, each of which were then transported to the laboratory on ice. Because the streambed at most 

sampling locations is predominantly gravel and cobble, deposits were selected where gravel and cobble could be excluded 

from the samples. Generally, bulk bed-sediment samples were 

composed of particles smaller than about 10 mm in diameter.

Bed-sediment samples were prepared for analysis at the 

USGS National Research Program laboratory in Menlo Park, 

Calif. Fine-grained and bulk bed-sediment samples were ovendried at 60 °C and ground using an acid-washed ceramic mortar 

and pestle. Duplicate aliquots of approximately 0.6 g of sediment from each of the three composite fine-grained bed-sediment samples were digested using a hot, concentrated, nitric 

acid reflux according to methods described by Luoma and 

Bryan (1981). Duplicate aliquots were similarly digested from 

the single composite sample of bulk bed sediment. After a 

digestion period of up to several weeks, the aliquots were evaporated to dryness on a hot plate. The dry residue was redissolved with 20 mL of 0.6N (normal) hydrochloric acid. The 

reconstituted aliquots then were filtered through a 0.45-nm filter using a syringe and in-line disposable filter cartridge. The 

filtrate was subsequently diluted to a 2:10, 3:10, or 5:10 ratio 

with 0.6N hydrochloric acid. These final solutions were analyzed for arsenic, cadmium, copper, iron, lead, manganese, 

nickel, silver, and zinc using inductively coupled argon plasma 

emission spectroscopy (ICAPES). Chromium data for the 2003 

samples were omitted from this report because the values were 

not reliable.

Results

Concentrations of trace elements measured in samples of 

fine-grained and bulk bed sediment collected during September 

2003 are summarized in tables 14 and 15, respectively. Liquidphase concentrations, in [ig/mL, that were analyzed in the 

reconstituted aliquots of digested bed sediment were converted 

to solid-phase concentrations, in ng/g, using the following 

equation:
10 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) and Statistical Summaries of Data for Streams

in the Upper Clark Fork Basin, Montana

x volume of digested sample, in mL (4) 

dry weight of sample, in g x dilution ratio

The reported solid-phase concentrations in tables 14 and 

15 are the means of all analyses of duplicate aliquots from each 

composite sample collected at the site. Because the conversion 

from liquid-phase to solid-phase concentration is dependent on 

both the dilution ratio and the dry weight of the sample, analytical detection limits for some trace elements might differ among 

stations and among years.

Quality Assurance

The protocols for field collection and processing of bedsediment 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 bedsediment 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 

precision (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" 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 SRM analyses that use less than a total digestion is useful to indicate which trace elements display strong 

sediment-binding characteristics in the SRM and whether analytical recovery is consistent between multiple sets of analyses.

Although data-quality objectives have not been established for bed sediment, percent recoveries shown in table 16 

illustrate analytical performance. Cadmium and silver concentrations were less than the analytical detection limit in the lowconcentration standard (SRM 2709). The reason for the lack of 

measurable recoveries for cadmium and silver in this SRM is 

believed to be the result of analyzing concentrations very close 

to the detection limit (0.0001 (ig/mL and 0.001 ^ig/mL, respectively) coupled with signal enhancement resulting from matrix 

interference. Percent recoveries for copper were 50.4 percent 

for the low-concentration standard (SRM 2709) and 66.2 percent for the high-concentration standard (SRM 2711). Arsenic 

and zinc in SRM 2709 and silver in SRM 2711 also displayed 

low recoveries (68.1 , 76.2, and 78.5 percent, respectively). 

Although these recovery values are relatively low, no adjustments were made to the data because the results from instrument calibration with standard solutions were well within 

acceptable limits (5-10 percent). Mean recoveries were within 

20 percent of complete recovery for all other constituents in 

both the low- and high-concentration SRMs and ranged from 

about 83 to 116 percent. No adjustments were made to traceelement concentrations in bed-sediment samples on the basis of 

recovery efficiencies.

Procedural blanks for bed-sediment samples consisted of 

the same reagents used for sample digestion and reconstitution. 

Concentrated nitric acid used for sample digestion was heated 

and evaporated to dryness. After evaporation, 0.6N hydrochloric acid was added to the dry residue. Procedural blanks, therefore, represent the same chemical matrix as the reagents used to 

digest and reconstitute bed-sediment samples. No dilution of 

the reagents was made prior to analysis in order to maximize 

and detect any potential contamination associated with sample 

handling and analysis in the laboratory environment. Results of 

trace-element analyses of procedural blanks for bed sediment 

are in table 17.

Analytical results of procedural blanks are reported as a 

liquid-phase concentration, in /<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 //g/g, relative to the ambient 

concentration of the trace element in bed-sediment samples. If 

a detectable blank concentration represents 10 percent or more 

of the ambient solid-phase concentration, then the blank concentration is subtracted to remove potential contamination bias. 

One procedural blank had a cadmium concentration at the analytical detection limit. However, because this one sample had a 

concentration less than 1 percent of the ambient concentration 

in environmental samples, no adjustments were made to traceelement concentrations in bed-sediment samples on the basis of 

procedural blanks.

Biological Data

Biological data consist of analyses of trace-element concentrations in the whole-body tissue of aquatic benthic insects. 

Insect samples were collected once-annually at the same sites 

and dates as bed-sediment samples (table 1), allowing for a
Biological Data 11

direct comparison of biological data among years and with bedsediment data.

Methods

Insect samples were collected using protocols described in 

Hornberger and others (1997). Immature stages of benthic 

insects were collected using a large nylon-mesh kick net. A single riffle at each station was sampled repeatedly until an adequate number of individuals was collected to provide sufficient 

mass for analysis. Targeted taxa for collection were Hydropsyche spp. 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 in samples frozen within 30 minutes of collection (M.I. Hornberger, unpub. data, 2000). The 

change in the field protocol minimizes the chance of metal loss 

through cell membranes during depuration and is consistent 

with methods established by Cain and Luoma (1998). However, caution needs to be exercised in comparing recent copper 

data for insects with earlier data because of the possibility of 

higher concentrations resulting from the change in field protocol.

Insect samples were processed and analyzed at the USGS 

National Research Program laboratory in Menlo Park, Calif. 

Insects were thawed and rinsed with ultra-pure deionized water 

to remove paniculate matter and then sorted to their lowest possible taxonomic level. If large numbers of specimens had been 

collected at a station, similar-sized individuals were composited 

into replicate subsamples. Subsamples were placed in tared 

scintillation vials and oven-dried at 70 °C. Subsamples were 

weighed to obtain a final dry weight and digested by reflux 

using concentrated nitric acid (Cain and others, 1992). After 

digestion, insect samples were evaporated to dryness on a hot 

plate. The dry residue was reconstituted in 0.6N hydrochloric 

acid, filtered through a 0.45-p,m filter, and analyzed undiluted 

by ICAPES for arsenic, cadmium, chromium, copper, iron, 

lead, manganese, nickel, and zinc.

Results

Concentrations of trace elements in whole-body tissue of 

aquatic insects collected during September 2003 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 traceelement 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 cockerelli and Hydropsyche occidentalis. 

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 (in 

previous reports). Arctopsyche grandis 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 equipment, 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 all tributary stations. 

Biota samples were collected sequentially at stations 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 quantify precision and to identify the presence and magnitude of 

bias. Quality-control samples consisted of a SRM and procedural blanks. Each type of sample was analyzed in a proportion 

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

samples.

Recovery efficiency for trace-element analyses of the 

SRM for biota is summarized in table 19. The reference material tested was lobster hepatopancreas. Data-quality objectives 

have not been established for analytical recovery in biota, but 

percent recoveries are shown to illustrate analytical performance. Mean SRM recoveries were within 12 percent of certified values for arsenic, cadmium, copper, iron, manganese, and 

zinc. Mean recoveries for chromium and nickel were within 26 

percent, and recoveries for lead were within 52 percent. The 

low recoveries for lead were attributed to 7 of the 12 samples 

having concentrations less than the instrument analytical detection limit. Additionally, a quality-control standard with a similar solution concentration as the SRM samples was analyzed 

throughout the analysis. Recoveries for all reported elements 

were within 10 percent of the quality-control standard.
12 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) and Statistical Summaries of Data for Streams 

in the Upper Clark Fork Basin, Montana

Results of trace-element analyses of procedural blanks for 

biota are in table 20. Procedural blanks for biota consisted of 

the same reagents used to digest and reconstitute tissue of 

aquatic insects. The blanks were analyzed undiluted at a proportion of one blank per site. Analytical results for all blanks 

were less than the analytical detection limit; thus, no contamination bias was indicated.

Statistical Summaries of Data

Statistical summaries of water-quality, bed-sediment, and 

biological data are provided in tables 21-24 for the period of 

record at each station since 1985. The summaries include the 

period of record, number of samples, maximum, minimum, 

mean, and median of concentrations.

Statistical summaries of water-quality data (table 21) are 

based on results of cross-sectional samples collected periodically by the USGS during the period of record for each station. 

The summaries do not include data for supplemental single-vertical samples collected during several years by a contract 

observer at Clark Fork at Turah Bridge, near Bonner; Blackfoot 

River near Bonner; and Clark Fork above Missoula. Inclusion 

of results for supplemental samples that targeted high-flow conditions or maintenance drawdowns of Milltown Reservoir 

would disproportionately skew the long-term statistics at these 

three sites relative to the other sites in the network. Statistical 

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

data (table 24) are based on results of samples collected onceannually during the indicated years. Because not all stations 

were sampled for bed sediment and biota every year, the data 

for some sites do not represent a consecutive annual record.

Sample sizes and statistics for bed-sediment data are based 

on a compilation of single annual-mean concentrations determined from the combined results of multiple composite samples for a given year. Therefore, sample sizes for bed sediment 

represent the number of years sampled. In contrast, sample 

sizes and statistics for biological data are based on individual 

analyses for each composite sample collected in an individual 

year, rather than on a single annual-mean concentration from all 

composites combined. Biota sample sizes reflect differences in 

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

the statistics for biota describe a wider range of variation in 

trace-element concentrations than would be evident if results 

from individual composite samples were averaged. The abundance of aquatic insects at a particular site in a given year limits 

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

analytical detection limits. Where analytical detection limits 

vary among years, statistical summaries are provided only as a 

general indication of the range of detection.

The presence or absence of insect species at a given site 

can vary among years and may result in different taxa being 

analyzed in the long-term period of record. Because Hydropsyche insects were not sorted to the species level during 

1986-89, statistics for stations sampled during those years are

based on the results of all Hydropsyche species combined. At 

some sites, statistics for the Hydropsyche morosa group are 

based on the combined results for two or more species because 

these samples could not be identified clearly to the species 

level, but the individual insects had morosa characteristics.

References Cited

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

tributary inflows on the distribution of trace metals in finegrained sediment and benthic insects of the Clark Fork River, 

Montana: Environmental Science and Technology, v. 31, no. 

3, p. 750-758.

Axtmann, E.V., and Luoma, S.N., 1991, Large scale distribution of metal contamination in the fine-grained sediment of 

the Clark Fork River, Montana: Applied Geochemistry, v. 6, 

no. 6, p. 75-88.

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

populations of the caddisfly Hydropsyche (TrichopteraHydropsychidae) determined from cytosolic and whole body 

metal concentrations: Hydrobiologia, v. 386, p. 103-117.

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

gut content in immature aquatic insects on assessments of 

environmental metal contamination: Canadian Journal of 

Fisheries and Aquatic Sciences, v. 52, no. 12, p. 2736-2746.

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

Aquatic insects as bioindicators of trace element contamination in cobble-bottom rivers and streams: Canadian Journal 

of Fisheries and Aquatic Sciences, v. 49, no. 10, p. 2141- 

2154.

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

T.J., 1999, New reporting procedures based on long-term 

method detection levels and some considerations for interpretations of water-quality data provided by the U.S. Geological Survey National Water Quality Laboratory: U.S. Geological Survey Open-File Report 99-193, 19 p.

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

Water-quality, bed-sediment, and biological data (October

1994 through September 1995) and statistical summaries of 

data for streams in the upper Clark Fork basin, Montana: 

U.S. Geological Survey Open-File Report 96-432, 109 p. 

Dodge, K.A., Hornberger, M.I., and Axtmann, E.V., 1997, 

Water-quality, bed-sediment, and biological data (October

1995 through September 1996) and statistical summaries of 

data for streams in the upper Clark Fork basin, Montana: 

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

Dodge, K.A., Hornberger, M.I., and Axtmann, E.V., 1998, 

Water-quality, bed-sediment, and biological data (October

1996 through September 1997) and statistical summaries of 

data for streams in the upper Clark Fork basin, Montana: 

U.S. Geological Survey Open-File Report 98-407, 102 p. 

Dodge, K.A., Hornberger, M.I., and Bouse, R.M., 1999, Waterquality, bed-sediment, and biological data (October 1997 

through September 1998) and statistical summaries of data
References Cited 13

for streams in the upper Clark Fork basin, Montana: U.S. 

Geological Survey Open-File Report 99-251, 102 p. 

Dodge, K.A., Hornberger, M.I., and David, C.P.C., 2000, 

Water-quality, bed-sediment, and biological data (October

1998 through September 1999) and statistical summaries of 

data for streams in the upper Clark Fork basin, Montana: 

U.S. Geological Survey Open-File Report 00-370, 102 p. 

Dodge, K.A., Hornberger, M.I., and David, C.P.C., 2001, 

Water-quality, bed-sediment, and biological data (October

1999 through September 2000) and statistical summaries of 

data for streams in the upper Clark Fork basin, Montana: 

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

Dodge, K.A., Hornberger, M.I., and David, C.P.C., 2002, 

Water-quality, bed-sediment, and biological data (October

2000 through September 2001) and statistical summaries of 

data for streams in the upper Clark Fork basin, Montana: 

U.S. Geological Survey Open-File Report 02-358, 94 p.

Dodge, K.A., Hornberger, M.I., and Lavigne, I.R., 2003, Waterquality, bed-sediment, and biological data (October 2001 

through September 2002) and statistical summaries of data 

for streams in the upper Clark Fork basin, Montana: U.S. 

Geological Survey Open-File Report 03-356, 95 p.

Edwards, T.K., and Glysson, G.D., 1999, Field methods for 

measurement of fluvial sediment: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 3, chap. 

C2, 89 p.

Faires, L.M., 1993, Methods of analysis by the U.S. Geological 

Survey National Water Quality Laboratory Determination 

of metals in water by inductively coupled plasma-mass spectrometry: U.S. Geological Survey Open-File Report 92-634, 

28 p.

Fishman, M.J., ed., 1993, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory Determination of inorganic and organic constituents in water and 

fluvial sediments: U.S. Geological Survey Open-File Report 

93-125, 217 p.

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

practices for the chemical and biological analyses of water 

and fluvial sediments: U.S. Geological Survey Techniques 

of Water-Resources Investigations, book 5, chap. A6, 181 p.

Garbarino, J.R., 1999, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory Determination of dissolved arsenic, boron, lithium, selenium, strontium, thallium, and vanadium using inductively coupled 

plasma-mass spectrometry: U.S. Geological Survey OpenFile Report 99-093, 31 p.

Garbarino, J.R., and Struzeski, T.M., 1998, Methods of analysis 

by the U.S. Geological Survey National Water Quality Laboratory Determination of elements in whole-water digests 

using inductively coupled plasma-optical emission spectrometry and inductively coupled plasma-mass spectrometry: 

U.S. Geological Survey Open-File Report 98-165, 101 p.

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

analysis: U.S. Geological Survey Techniques of WaterResources Investigations, book 5, chap. Cl, 58 p.

Helsel, D.R., and Cohn, T.A., 1988, Estimation of descriptive 

statistics for multiply censored water quality data: Water 

Resources Research, v. 24, no. 12, p. 1997-2004.

Hoffman, G.L., Fishman, M.J., and Garbarino, J.R., 1996, 

Methods of analysis by the U.S. Geological Survey National 

Water Quality Laboratory In-bottle acid digestion of 

whole-water samples: U.S. Geological Survey Open-File 

Report 96-225, 28 p.

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.

Jones, S.R., and Garbarino, J.R., 1999, Methods of analysis by 

the U.S. Geological Survey National Water Quality Laboratory Determination of arsenic and selenium in water and 

sediment by graphite furnace-atomic absorption spectrometry: U.S. Geological Survey Open-File Report 98-639, 39 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.

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.
14 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) and Statistical Summaries of Data for Streams 

in the Upper Clark Fork Basin, Montana

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

laboratory analysis of suspended-sediment samples by the 

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

Open-File Report 93-131, 34 p.

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

K.A., 1995, Water-quality, bed-sediment, and biological data 

(October 1993 through September 1994) and statistical summaries of data for 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, no. 17, p. 167-196.

Porterfield, George, 1972, Computation of fluvial-sediment discharge: U.S. Geological Survey Techniques of WaterResources Investigations, book 3, chap. C3, 66 p.

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

assurance/quality control manual National Water Quality 

Laboratory: U.S. Geological Survey Open-File Report 95- 

443, 35 p.

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

streamflow: U.S. Geological Survey Water-Supply Paper 

2175, 2 v., 631 p.

Taylor, J.K., 1987, Quality assurance of chemical measurements: Chelsea, Mich., Lewis Publishers, 328 p.

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

services catalog: U.S. Geological Survey Open-File Report 

94-304, 103 p.

U.S. Geological Survey, variously dated, National field 

manual for the collection of water-quality data: U.S. 

Geological Survey Techniques of Water-Resources 

Investigations, book 9, chaps. Al-A-9; available online at 

http://pubs.water.usgs.gov/twri9A

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.
DATA 15

DATA
16 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003

[The terms "filtered" and "unfiltered recoverable" replace the former terms "dissolved" and "total recoverable," respectively. Abbreviations: ft3/s, 

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

milligrams per liter; mm, millimeter; ton/d, tons per day. Symbols: <, less than analytical detection limit; , no data]

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

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Streamflow, pH, Specific Temper- Hardness, _ . MagneT. instan- onsite conduct- ature, filtered ,. u ,' sium, Time ^ , A . . . . / /i filtered ,. IJL ' taneous (standard ance, onsite water (mg/L as , ... filtered

(frVs) units) (fiS/cm) (°C) CaC03 ) (mg/ ' (mg/L)

0850

0850

1015

0810

1550

0720

1000

1015

9.0

16

15

6.8

6.9

3.5

2.6

2.7

7.6 246

7.8 211

7.8 242

7.8 251

8.4 266

7.7 323

7.8 342

7.8 337

1.5 87

3.0 77

4.5 93

12.0 100

16.0 110

9.5 130

11.5 140

11.0 140

24.4

21.4

26.8

29.5

32.2

35.6

41.5

39.3

6.27

5.66

6.31

6.76

7.37

9.00

9.54

9.43

Arsenic, 

filtered

(ng/L)

5.0

4.4

3.6

5.1

6.1

2.8

2.0

1.6

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Arsenic, 

unfiltered 

recoverable 

(|ig/L)

6

6

5

6

7

3

E2

3

Cadmium, 

filtered 

N/L)

0.04

.10

.09

.07

E.03

.04

.06

.08

Cadmium, 

unfiltered 

recoverable 

(ng/L)

0.09

.11

.05

.04

.04

E.03

E.02

E.03

Copper, 

filtered 

WL)

5.5

6.8

5.6

5.0

4.1

2.1

1.4

1.8

Copper, 

unfiltered 

recoverable 

(fig/L)

12.5

16.9

7.8

6.3

5.2

2.5

2.2

3.1

Iron, 

filtered 

(fxg/L)

278

312

280

188

209

72

25

22

Iron, 

unfiltered 

recoverable 

(u.g/L)

1,130

1,450

590

370

420

260

200

190

Lead, 

filtered 

(ng/L)

0.40

.62

.32

.16

.10

.35

<.08

<.08

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Lead, 

unfiltered 

recoverable 

(fig/L)

3.78

4.86

.81

.36

.38

.26

.20

.22

Manganese, 

filtered 

(u.g/L)

140

39.7

30.5

30.4

18.6

50.2

38.8

39.7

Manganese, 

unfiltered 

recoverable 

WD

164

72

35

32

24

50

41

45

Zinc, 

filtered 

(ng/U

5

8

4

5

<1

5

3

3

Zinc, 

unfiltered 

recoverable 

(H9/U

15

27

6

4

3

3

3

3

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

85

82

82

89

87

96

83

81

Sediment, 

suspended 

(mg/L)

23

31

7

3

5

2

3

3

Sediment 

discharge, 

suspended 

(ton/d)

0.56

1.3

.28

.06

.09

.02

.02

.02
TABLE 4 17

Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2002 through September 2003 Continued

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

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Streamflow, pH, Specific Temper- Hardness, p . . .' K , . . K ,. u , Calcium T. mstan- onsite conduct- ature, filtered .... , Time . , . , . .. . , ,. filtered taneous (standard ance, onsite water (mg/L as , ...

(ft3/s) units) (nS/cm) (°C) CaC03 ) |mg/ '

1000

1010

1120

0845

1700

0830

1120

1040

29

31

28

20

18

15

14

16

7.6 402

7.5 400

7.5 435

7.7 451

8.0 482

7.6 532

7.9 512

7.6 539

3.0 120

5.0 120

7.5 140

12.5 150

17.0 160

13.0 160

18.0 160

17.5 160

34.4

34.6

38.4

42.2

44.0

45.3

44.3

43.5

Magnesium, 

filtered 

(mg/L)

8.58

8.81

9.55

10.7

10.9

11.8

10.8

11.5

Arsenic, 

filtered 

(ng/L)

6.4

5.2

5.3

6.4

7.5

5.4

6.4

5.6

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Arsenic, 

unfiltered 

recoverable 

(ng/U

9

8

6

8

9

6

6

6

Cadmium, 

filtered 

(ng/L)

.25

.23

.24

.24

.13

.23

.09

.15

Cadmium, 

unfiltered 

recoverable 

(u.g/L)

.52

.40

.28

.30

.24

.29

.11

.17

Copper, 

filtered 

(ng/U

10.3

14.1

10.9

12.2

12.2

13.2

8.4

9.8

Copper, 

unfiltered 

recoverable

(ng/U

32.3

35.8

17.2

21.8

21.3

20.0

15.6

16.2

Iron, 

filtered 

(u.g/L)

191

173

145

84

44

30

22

24

Iron, 

unfiltered 

recoverable 

(M-g/L)

1,060

1,380

440

380

320

250

120

120

Lead, 

filtered 

(fxg/U

.79

.74

.30

.24

.19

.26

.20

.24

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Lead, 

unfiltered 

recoverable

wu

7.38

10.5

1.60

1.89

1.53

1.50

.65

1.03

Manganese, 

filtered 

(|ig/L)

245

144

178

196

132

153

22.2

75.6

Manganese, 

unfiltered 

recoverable 

(ng/L)

297

212

163

196

146

156

26

85

Zinc, 

filtered 

WL)

110

86

102

80

47

88

34

59

Zinc, 

unfiltered 

recoverable 

(ng/U

169

139

111

107

77

106

45

66

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

83

92

88

87

90

92

86

86

Sediment, 

suspended 

(mg/L)

24

39

7

7

6

4

4

2

Sediment 

discharge, 

suspended 

(ton/d)

1.9

3.3

.53

.38

.29

.16

.15

.09
18 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003 Continued

12323600--SILVER BOW CREEK AT OPPORTUNITY, MONT.

Date

MAR 2003

15...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

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

 1 j * * «-u j Calcium, . T. mstan- onsite conduct- ature, filtered ,... , sium, Time x i * j j -. * i /i filtered ,. u , taneous (standard ance, onsite water (mg/Las , ... filtered

(ftVs) units) (nS/cm) (°C) CaC03) (mg/ ' (mg/L)

0930

1115

1220

1000

1430

1145

1225

1315

176

61

75

101

90

39

13

17

7.8 276

8.1 418

8.4 385

8.4 331

8.7 318

9.1 407

8.9 574

8.8 572

1.5 81

5.5 140

6.5 140

10.5 130

14.0 130

16.0 160

21.0 210

20.0 200

24.2

40.3

41.7

40.8

40.5

48.5

61.9

59.1

4.96

9.01

8.72

7.15

7.25

9.74

12.9

13.3

Arsenic, 

filtered 

(fig/L)

14.7

11.0

10.3

11.5

9.5

12.5

22.1

19.3

Date

MAR 2003

15...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Arsenic, 

unfiltered 

recoverable 

WU

91

27

15

14

14

15

22

28

Cadmium, 

filtered 

(u.g/L)

2.08

1.45

.84

.37

.29

.35

.23

.78

Cadmium, 

unfiltered 

recoverable 

(|ig/L)

5.22

2.23

1.18

.78

.58

.69

.52

1.31

Copper, 

filtered 

(fig/U

142

69.7

50.0

28.5

25.4

30.4

25.3

37.8

Copper, 

unfiltered 

recoverable 

(u.g/L)

860

214

97.0

73.9

60.6

61.1

54.3

95.2

Iron, 

filtered 

(u.g/L)

141

71

90

55

38

30

32

9

Iron, 

unfiltered 

recoverable 

(u.g/L)

8,760

1,600

760

780

620

430

280

290

Lead, 

filtered 

(fxg/L)

3.17

1.38

.92

.39

.27

.31

.39

.26

Date

MAR 2003

15...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Lead, 

unfiltered 

recoverable 

(u.g/L)

269

52.9

15.5

12.4

10.2

7.47

5.38

7.43

Manganese, 

filtered 

(ng/L)

767

521

343

227

172

203

85.7

279

Manganese, 

unfiltered 

recoverable 

N/L)

1,190

635

349

274

211

248

117

329

Zinc, 

filtered 

(jig/L)

491

336

177

59

40

38

28

82

Zinc, 

unfiltered 

recoverable 

(u.g/D

1,230

539

251

163

119

139

97

204

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

83

88

91

86

84

84

81

80

Sediment, 

suspended 

(mg/L)

238

56

18

28

17

9

5

6

Sediment 

discharge, 

suspended 

(ton/d)

113

9.2

3.6

7.6

4.1

.95

.18

.28
TABLE 4 19

Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2002 through September 2003 Continued

12323700-MILL CREEK AT OPPORTUNITY, MONT.

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

11...

16...

JUL

28...

AUG

25...

Streamflow, pH, Specific Temper- Hardness, r . . .' j 4 * ru A Calcium, 

_. mstan- onsite conduct- ature, filtered ,. u , Time A , x . , .x ,. , filtered taneous (standard ance, onsite water (mg/Las , ...

(tf/s) units) (nS/cm) (°C) CaC03 ) (mg/ '

1210

1255

1345

1220

1430

1005

1420

1230

9.6

14

21

110

261

79

3.6

2.1

8.2 207

8.0 186

8.0 129

7.8 81

7.8 59

7.9 83

8.1 169

8.1 195

3.0 85

5.0 73

5.5 51

9.5 32

9.5 24

9.0 37

18.5 74

16.0 85

23.0

20.0

14.4

9.14

7.01

10.6

21.0

23.5

Magnesium, 

filtered 

(mg/L)

6.57

5.69

3.74

2.23

1.57

2.55

5.36

6.32

Arsenic, 

filtered 

(ng/L)

37.0

33.2

33.6

29.9

23.0

20.5

31.5

29.7

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

11...

16...

JUL

28...

AUG

25...

Arsenic, 

unfiltered 

recoverable 

(ng/L)

38

36

35

50

36

22

32

35

Cadmium, 

filtered 

(Ml/1-)

.08

.09

.10

.08

.08

.06

.05

.05

Cadmium, 

unfiltered 

recoverable 

(ng/D

.11

.11

.15

.85

.51

.13

.06

.06

Copper, 

filtered

(ng/U

3.7

4.7

5.2

5.8

6.0

3.3

2.4

2.2

Copper, 

unfiltered 

recoverable 

(ng/L)

5.0

7.5

8.0

38.8

25.1

6.9

3.3

3.2

Iron, 

filtered 

(ng/U

39

37

51

53

50

41

45

60

Iron, 

unfiltered 

recoverable 

WL)

120

200

210

1,960

1,300

320

100

100

Lead, 

filtered 

(ng/L)

.18

.17

.23

.32

.27

.22

.14

.11

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

11...

16...

JUL

28...

AUG

25...

Lead, 

unfiltered 

recoverable 

WL)

.48

1.08

1.19

12.7

8.01

1.74

.30

.17

Manganese, 

filtered

(M-g/D

3.6

4.8

4.4

15.7

7.0

6.4

11.1

9.8

Manganese, 

unfiltered 

recoverable 

(ng/D

6

10

14

113

64

17

12

11

Zinc, 

filtered 

(ng/L)

3

4

6

3

4

3

2

2

Zinc, 

unfiltered 

recoverable 

(|ig/L)

5

8

7

41

26

10

2

3

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

78

87

78

49

52

51

88

80

Sediment, 

suspended 

(mg/L)

1

5

6

107

78

10

1

1

Sediment 

discharge, 

suspended 

(ton/d)

.03

.19

.34

32

55

2.1

.01

.01
20 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003 Continued

12323720--WILLOW CREEK AT OPPORTUNITY, MONT.

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

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

_. instan- onsite conduct- ature, filtered ,. u ' sium, Time , i * j j -,. * in filtered .... , taneous (standard ance, onsite water (mg/Las , ... filtered

(ft3/s) units) (piS/cm) (°C) CaC03) lmg/ ' (mg/L)

1100

1145

1250

1040

1445

0925

1305

1200

9.8

14

20

46

33

14

6.3

6.6

8.0 318

8.3 333

8.1 181

7.9 225

7.9 213

7.9 261

8.2 322

8.0 307

3.5 140

5.5 130

6.0 73

11.5 98

13.5 95

11.5 110

17.0 150

14.5 130

38.7

36.8

22.0

28.5

27.8

31.9

42.6

38.3

9.38

9.27

4.37

6.58

6.19

7.80

9.89

9.53

Arsenic, 

filtered 

WD

33.1

57.0

26.1

101

69.4

42.6

24.2

13.2

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Arsenic, 

unfiltered 

recoverable 

WD

35

65

27

104

69

44

23

16

Cadmium, 

filtered 

(ng/L)

.06

.05

.04

.08

.05

.05

E.03

.05

Cadmium, 

unfiltered 

recoverable

wu

.07

.10

.11

.30

.13

.09

.04

.05

Copper, 

filtered 

(|ig/L)

4.2

7.9

5.6

14.1

9.2

4.5

2.7

2.4

Copper, 

unfiltered 

recoverable 

(fxg/D

10.6

17.1

11.8

36.9

17.0

9.5

4.5

4.4

Iron, 

filtered 

(fxg/L)

34

49

70

87

48

47

14

8

Iron, 

unfiltered 

recoverable 

(ng/L)

210

250

410

840

290

220

80

100

Lead, 

filtered

(ng/L)

.24

.28

.30

.50

.21

.28

E.06

.19

Date

MAR 2003

17...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Lead, 

unfiltered 

recoverable 

(fxg/L)

2.12

1.98

2.67

8.41

2.55

1.72

.78

.71

Manganese, 

filtered 

(ng/L)

49.3

37.9

24.2

32.8

18.7

19.0

10.6

13.2

Manganese, 

unfiltered 

recoverable 

(M-9/L)

62

46

38

70

31

24

14

18

Zinc, 

filtered 

(HQ/L)

8

6

10

8

5

5

2

2

Zinc, 

unfiltered 

recoverable 

(ng/D

16

15

14

41

15

10

4

4

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

93

94

86

76

76

91

88

96

Sediment, 

suspended 

(mg/L)

5

9

17

51

15

6

3

2

Sediment 

discharge, 

suspended 

(ton/d)

.13

.34

.92

6.3

1.3

.23

.05

.04
TABLE 4 21

Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2002 through September 2003 Continued

12323750-SILVER BOW CREEK AT WARM SPRINGS, MONT.

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

01...

16...

JUL

28...

AUG

25...

Streamflow, pH, Specific Temper- Hardness, . . 

 * -4. j * * x-u j Calcium 

_. mstan- onsite conduct- ature, filtered ,. u , Time . . . . . ., , , filtered taneous (standard ance, onsite water (mg/Las , ...

(frVs) units) (fiS/cm) (°C) CaC03 ) lmg/ '

0925

1435

1500

1350

1650

1310

1520

1415

132

121

137

213

424

137

22

24

8.4 494

8.5 492

8.4 438

8.9 278

8.6 253

9.0 265

9.0 524

9.0 578

4.5 190

7.0 200

8.5 170

14.0 110

15.5 110

15.5 100

25.0 240

21.5 260

57.3

58.6

51.2

30.5

31.1

30.0

69.5

75.9

Magnesium, 

filtered 

(mg/L)

11.6

12.3

10.9

7.35

6.68

7.18

16.0

17.7

Arsenic, 

filtered 

(ng/L)

19.5

15.8

16.3

37.9

39.3

28.6

30.6

26.0

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

01...

16...

JUL

28...

AUG

25...

Arsenic, 

unfiltered 

recoverable 

(jig/L)

31

19

19

43

43

30

30

32

Cadmium, 

filtered 

(ng/L)

.31

.04

.05

.05

.06

.04

E.03

.07

Cadmium, 

unfiltered 

recoverable 

(ng/L)

.56

.11

.17

.36

.15

.10

.06

.05

Copper, 

filtered 

(ng/U

27.8

7.0

6.3

8.6

8.5

5.7

3.5

4.5

Copper, 

unfiltered 

recoverable 

(HQ/L)

96.8

18.4

13.3

23.8

14.4

8.9

7.1

6.6

Iron, 

filtered

(ng/L)

26

15

16

36

43

35

10

E6

Iron, 

unfiltered 

recoverable 

WD

1,420

340

270

760

320

200

110

100

Lead, 

filtered 

(jig/D

.57

.14

.11

.27

.17

.14

<.08

E.06

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

01...

16...

JUL

28...

AUG

25...

Lead, 

unfiltered 

recoverable 

(fig/L)

41.8

5.13

2.16

6.32

1.78

1.20

.73

.47

Manganese, 

filtered 

(jig/L)

405

122

78.7

34.2

69.1

42.3

53.0

72.4

Manganese, 

unfiltered 

recoverable 

WD

493

172

114

110

117

81

98

122

Zinc, 

filtered 

(ng/D

37

7

2

<1

1

2

1

7

Zinc, 

unfiltered 

recoverable 

(ng/D

158

32

18

28

12

8

5

5

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

97

92

88

90

83

86

83

53

Sediment, 

suspended 

(mg/L)

24

7

8

31

11

5

4

5

Sediment 

discharge, 

suspended 

(ton/d)

8.6

2.3

3.0

18

13

1.8

.24

.32
22 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003 Continued

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

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

01...

16...

JUL

28...

AUG

25...

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

. . ' j * f-u j Calcium, . T. mstan- onsite conduct- ature, filtered ... ' smm, Time * / A j j * x / /i filtered ,. u ' taneous (standard ance, onsite water (mg/L as , ... filtered

(ftfys) units) (u,S/cm) (°C) CaC03 ) |ma/ ' (mg/L)

0910

1415

1425

1425

1510

1225

1500

1355

39

46

57

137

389

154

25

36

8.4 369

8.5 358

8.5 308

8.1 179

8.0 155

8.2 185

8.7 312

8.5 292

3.0 180

5.5 170

6.5 150

11.5 86

10.0 72

11.5 85

20.0 160

16.0 140

54.6

51.3

45.1

26.9

22.5

25.9

48.3

43.6

10.8

10.4

8.65

4.54

3.85

5.05

8.53

8.10

Arsenic, 

filtered 

(jig/D

4.9

4.8

4.4

7.8

11.6

5.2

9.3

5.8

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

01...

16...

JUL

28...

AUG

25...

Arsenic, 

unfiltered 

recoverable 

(ng/L)

5

4

4

17

20

6

9

7

Cadmium, 

filtered

.06

E.04

E.03

E.03

.06

E.03

E.03

E.03

Cadmium, n 

,. u ' Copper, unfiltered ,. u ' 

. . filtered recoverable , ,. , ( ^g/L) (fxg/L)

E.03 2.5

E.03 3.0

.06 3.1

.36 5.1

.24 11.1

.07 3.4

E.03 3.2

.04 2.9

Copper, 

unfiltered 

recoverable 

(ng/L)

7.5

7.1

8.9

89.5

66.6

12.5

5.9

6.9

Iron, 

filtered 

(ng/L)

E9

11

E8

22

28

15

12

9

Iron, 

unfiltered 

recoverable 

(u.g/L)

110

80

110

1,670

1,010

180

60

80

Lead, 

filtered

.32

E.07

E.05

.12

.12

E.05

<08

E.08

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

01...

16...

JUL

28...

AUG

25...

Lead, 

unfiltered 

recoverable 

(|Ag/L)

.79

.44

.76

10.7

5.58

1.08

.27

.40

Manganese, 

filtered

210

143

110

91.3

41.2

65.3

52.8

36.8

Manganese, ... * . Zinc, unfiltered .... ' 

. . filtered recoverable , . 

, , u^g/L) (^g/L)

255 2

182 <1

150 <1

580 <1

189 2

93 2

80 <1

95 <1

Zinc, 

unfiltered 

recoverable 

(ng/D

4

3

4

38

24

5

E2

E2

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

69

58

71

68

70

69

74

80

Sediment, 

suspended 

(mg/L)

5

5

6

94

56

8

2

3

Sediment 

discharge, 

suspended 

(ton/d)

.53

.62

.92

35

59

3.3

.14

.29
TABLE 4 23

Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2002 through September 2003 Continued

12323800-CLARK FORK NEAR GALEN, MONT.

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

01...

16...

JUL

28...

AUG

25...

Streamflow, pH, Specific Temper- Hardness, .

T. instan- onsite conduct- ature, filtered ,. u ' Time A , , . . .x * i /i filtered taneous (standard ance, onsite water (mg/Las , ...

(ftVs) units) (nS/cm) (°C) CaC03) UnB/u

1015

1535

1545

1515

1610

1350

1620

1515

180

175

193

352

905

275

42

56

8.3 471

8.5 462

8.4 408

8.5 243

8.3 216

8.6 232

8.6 430

8.6 414

4.5 190

6.5 190

8.0 170

14.5 100

13.0 91

14.5 97

21.5 200

19.0 190

57.8

56.8

50.7

30.5

27.5

28.7

60.9

55.8

Magnesium, 

filtered 

(mg/L)

11.6

11.7

10.5

6.51

5.46

6.25

12.3

12.1

Arsenic, 

filtered 

(jig/L)

16.1

12.5

13.0

27.0

26.2

16.6

17.1

12.7

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

01...

16...

JUL

28...

AUG

25...

Arsenic, 

unfiltered 

recoverable 

H/L)

26

17

15

36

37

19

17

17

Cadmium, 

filtered 

(ng/L)

.25

.05

.05

E.03

.07

E.04

.04

E.03

Cadmium, 

unfiltered 

recoverable 

(M-g/D

.43

.11

.15

.44

.30

.10

.06

.06

Copper, 

filtered 

(ng/L)

21.1

6.3

5.7

8.2

11.1

5.0

4.0

3.9

Copper, 

unfiltered 

recoverable 

(ng/L)

74.9

21.8

16.7

68.0

56.8

15.7

9.1

8.9

Iron, 

filtered

(ng/U

18

12

14

27

, 31

22

10

E5

Iron, 

unfiltered 

recoverable

(ng/L)

1,120

340

260

1,250

950

240

110

140

Lead, 

filtered 

(ng/L)

.46

.12

.09

.23

.18

.09

<.08

E.05

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

01...

16...

JUL

28...

AUG

25...

Lead, 

unfiltered 

recoverable 

(HQ/U

31.0

4.38

2.15

10.1

6.94

1.91

.78

.65

Manganese, 

filtered 

(fig/U

325

105

74.2

63.0

52.4

49.6

53.2

36.3

Manganese, 

unfiltered 

recoverable 

(|ig/L)

410

183

138

406

227

103

97

82

Zinc, 

filtered 

(jig/L)

31

6

4

<1

5

2

2

2

Zinc, 

unfiltered 

recoverable 

(fxg/D

116

28

18

46

41

12

6

5

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

90

74

76

80

55

68

85

78

Sediment, 

suspended 

(mg/L)

23

11

10

62

52

9

3

3

Sediment 

discharge, 

suspended 

(ton/d)

11

5.2

5.2

59

127

6.7

.34

.45
24 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003 Continued

12323850--LOST CREEK NEAR GALEN, MONT.

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

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

_. instan- onsite conduct- ature, filtered ,. u ' sium, Time , . , .^ . , filtered ,. u , taneous (standard ance, onsite water (mg/L as . ... filtered

(frVs) units) (nS/cm) (°C) CaC03 ) lm9/L) (mg/L)

1050

1605

1610

1545

1250

1435

1700

1540

48

59

18

13

15

4.4

1.3

5.0

8.4 643

8.5 861

8.6 627

8.7 549

8.6 579

8.6 625

8.6 540

8.5 638

4.5 320

7.0 420

8.5 300

19.0 270

13.5 290

23.0 280

26.5 200

22.5 290

92.0

117

88.2

77.4

84.3

78.8

48.5

79.7

20.8

32.3

20.3

18.0

19.0

21.2

19.9

22.0

Arsenic, 

filtered 

(HO/L)

19.5

41.8

11.7

14.8

15.5

10.5

10.3

13.2

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Arsenic, 

unfiltered 

recoverable 

(ng/L)

21

43

11

14

16

10

9

16

Cadmium, 

filtered 

H/L)

E.03

.05

E.03

E.03

E.03

E.02

E.02

E.02

Cadmium, 

unfiltered 

recoverable

.06

.11

.05

.04

.04

E.03

E.03

E.02

p Copper,

C°pper: unfiltered filtered , . 

, .. , recoverable

(W1/L| (M/U

2.9 13.0

6.7 22.5

2.5 5.8

3.5 6.8

3.4 7.3

3.0 4.4

3.2 4.5

2.6 4.5

Iron, 

filtered 

(ng/L)

E7

18

E6

E6

E6

E4

<8

<8

Iron, 

unfiltered 

recoverable 

(ng/D

270

280

70

70

80

40

20

10

Lead, 

filtered 

(ng/L)

.10

.33

<.08

E.05

<.08

<.08

<.08

<.08

Date

MAR 2003

18...

APR

02...

28...

MAY

26...

JUN

03...

16...

JUL

28...

AUG

25...

Lead, 

unfiltered 

recoverable

1.23

1.30

.32

.30

.32

.14

E.04

E.04

Manganese, 

filtered 

(M-g/U

19.5

23.6

14.2

8.5

8.6

5.3

2.0

1.9

Manganese, 

unfiltered 

recoverable 

(jig/D

30

33

15

13

13

8

2

3

... Zinc, Zinc, ,. u . 

... ' unfiltered filtered , , 

, .. , recoverable

(M/U (WI/LI

1 7

2 9

<1 3

<1 3

<1 3

1 E2

<1 El

<1 <2

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

65

59

66

43

46

18

77

51

Sediment, 

suspended 

(mg/L)

16

24

5

9

9

8

2

16

Sediment 

discharge, 

suspended 

(ton/d)

2.1

3.8

.24

.32

.36

.10

.01

.22
TABLE 4 25

Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2002 through September 2003 Continued

12324200--CLARK FORK AT DEER LODGE, MONT.

Date

MAR 2003

18...

APR

03...

28...

MAY

26...

JUN

01...

16...

JUL

29...

AUG

25...

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

 1 j * n j Calcium, 

,. mstan- onsite conduct- ature, filtered ,. u . Time x , , , , ., . i 11 filtered taneous (standard ance, onsite water (mg/Las , ...

(ffVs) units) (nS/cm) (°C) CaC03 ) (mg/ '

1215

0720

1730

1725

1900

1515

0730

1635

342

347

282

471

1,010

347

40

80

8.2 515

8.2 576

8.6 460

8.1 278

8.0 250

8.3 303

8.0 495

8.6 495

5.0 220

3.5 250

9.5 190

16.5 120

14.0 110

18.5 130

15.5 210

21.0 220

64.6

72.4

57.2

34.7

32.2

38.6

63.8

64.6

Magnesium, 

filtered 

Img/L)

13.5

17.2

12.3

7.26

6.44

8.19

12.8

13.5

Arsenic, 

filtered 

(ng/D

16.2

16.7

13.7

19.5

23.7

17.0

17.8

15.8

Date

MAR 2003

18...

APR

03...

28...

MAY

26...

JUN

01...

16...

JUL

29...

AUG

25...

Arsenic, 

unfiltered 

recoverable 

(jig/L)

27

25

17

34

53

21

17

20

Cadmium, 

filtered 

((Jtg/L)

.12

.07

.06

.06

.08

.06

.06

.04

Cadmium, 

unfiltered 

recoverable 

(ng/L)

.41

.33

.18

.65

.88

.20

.07

.11

Copper, 

filtered 

(ng/L)

14.0

9.9

7.6

13.0

18.7

9.6

8.0

6.6

Copper, 

unfiltered 

recoverable 

(ng/L)

95.8

66.1

31.1

119

241

38.3

13.5

17.8

Iron, 

filtered 

(ng/D

12

18

E8

27

44

24

9

<8

Iron, 

unfiltered 

recoverable 

(jig/L)

1,420

1,040

460

2,020

2,910

490

80

150

Lead, 

filtered 

(^g/D

.25

.14

E.07

.24

.54

.14

<.08

E.06

Date

MAR 2003

18...

APR

03...

28...

MAY

26...

JUN

01...

16...

JUL

29...

AUG

25...

Lead, 

unfiltered 

recoverable

(ng/L)

22.1

10.2

4.08

18.0

33.9

4.88

.67

1.46

Manganese, 

filtered

(ng/D

83.9

51.2

27.1

36.2

40.9

26.2

34.4

17.1

Manganese, 

unfiltered 

recoverable 

(H9/U

259

204

112

339

402

100

48

73

Zinc, 

filtered 

(jig/L)

19

9

3

4

9

6

8

3

Zinc, 

unfiltered 

recoverable 

(ng/U

102

67

30

108

167

32

13

13

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

68

57

68

70

52

64

88

69

Sediment, 

suspended 

(mg/L)

60

55

22

94

187

24

3

14

Sediment 

discharge, 

suspended 

(ton/d)

55

52

17

120

510

22

.32

3.0
26 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003 Continued

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON, MONT.

Date

AUG 2003

27... 

SEP

22...

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

 *. -1 j . x x-u -i Calcium, T. mstan- onsite conduct- ature, filtered .... , Time x / ^ j j -. . / /i filtered taneous (standard ance, onsite water (mg/Las . ...

(ftVs) units) (nS/cm) (°C) CaC03 ) |mg/ '

0815 

1000

25 

40

8.0 347 

8.2 321

14.5 170 

9.0 150

49.3 

44.6

Magnesium, 

filtered 

(mg/L)

11.9

9.84

Arsenic, 

filtered 

(MI/L)

5.7 

4.7

Date

AUG 2003

27... 

SEP 

22...

Arsenic, 

unfiltered 

recoverable 

(ng/L)

5 

5

Cadmium, 

filtered 

(W/L)

<.04 

.04

Cadmium, 

unfiltered 

recoverable 

(H9/L)

<.04 

<.04

 Copper, Copper, ,.;7 ' ....^ ' unfiltered filtered . . 

, , recoverable

|M/L| I M/U

.9 1.1

.8 2.3

Iron, 

filtered 

WL)

13

E7

Iron, 

unfiltered 

recoverable 

(M-g/L)

60 

50

Lead, 

filtered

(i*g/D

<.08 

<08

Date

AUG 2003

27... 

SEP

22...

Lead, 

unfiltered 

recoverable 

(ng/L)

.06 

.07

Manganese, 

filtered 

WU

20.4 

11.4

Manganese, 

unfiltered 

recoverable 

(M-g/L)

28 

19

... Zinc, Zinc, .... , 

..... . unfitered filtered . . 

, . recoverable ( ^9/L) (ng/D

1 <2 

<1 El

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

95 

94

Sediment, 

suspended 

(mg/L)

2 

2

Sediment 

discharge, 

suspended 

(ton/d)

.14

.22
TABLE 4 27

Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2002 through September 2003 Continued

12324680--CLARK FORK AT GOLDCREEK, MONT.

Date

MAR 2003

15...

APR

03...

29...

MAY

27...

JUN

03...

16...

JUL

29...

AUG

26...

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

 . -1 j * * ru j Calcium mstan- onsite conduct- ature, filtered ,.. . Time A , t . , ., , , filtered taneous (standard ance, onsite water (mg/Las , ...

(ft3/s) units) (jxS/cm) (°C) CaC03 ) |mg/ '

1210

0900

0750

1000

1105

1645

0825

0740

1,340

718

870

1,760

1,820

747

146

146

8.1 345

8.4 447

8.2 308

8.0 206

8.1 239

8.7 306

8.3 432

8.2 492

3.0 140

4.0 190

5.0 130

11.0 90

10.5 100

19.5 140

16.0 200

15.5 220

39.9

56.7

39.7

27.0

30.9

40.1

59.9

65.3

Magnesium, 

filtered 

(mg/L)

8.67

12.9

8.66

5.43

6.22

8.72

11.5

13.8

Arsenic, 

filtered 

(ng/L)

12.3

10.4

7.4

10.2

13.3

12.1

13.3

11.7

Date

MAR 2003

15...

APR

03...

29...

MAY

27...

JUN

03...

16...

JUL

29...

AUG

26...

Arsenic, 

unfiltered 

recoverable 

(H-g/L)

26

15

10

19

24

13

12

15

Cadmium, 

filtered 

(fxg/D

.14

.06

E.03

.04

.06

.04

E.03

E.03

Cadmium, 

unfiltered 

recoverable 

(ng/L)

.59

.20

.14

.43

.50

.11

.09

.08

Copper, 

filtered 

(jig/L)

13.8

7.1

4.3

7.4

11.1

7.0

4.4

4.2

Copper, 

unfiltered 

recoverable 

(ng/L)

122

42.4

21.3

78.0

98.7

20.8

13.0

11.2

Iron, 

filtered 

(jxg/L)

47

28

28

71

38

14

44

E4

Iron, 

unfiltered 

recoverable 

(M/L)

2,650

750

640

2,020

1,630

300

520

230

Lead, 

filtered 

(M-g/L)

.35

.14

.10

.26

.35

E.06

<.08

E.05

Date

MAR 2003

15...

APR

03...

29...

MAY

27...

JUN

03...

16...

JUL

29...

AUG

26...

Lead, 

unfiltered 

recoverable 

(M-g/L)

20.2

5.96

3.24

13.1

13.8

2.40

1.56

.97

Manganese, 

filtered

wu

35.2

28.6

14.0

11.2

19.2

16.4

16.2

13.8

Manganese, 

unfiltered 

recoverable 

(M-g/L)

348

106

84

234

223

57

90

78

Zinc, 

filtered 

(ng/L)

n

n

3

2

6

2

2

2

Zinc, 

unfiltered 

recoverable 

(ng/U

122

44

24

83

91

17

15

10

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

66

76

69

64

60

79

94

89

Sediment, 

suspended 

(mg/L)

129

35

32

123

93

12

22

13

Sediment 

discharge, 

suspended 

(ton/d)

467

68

75

584

457

24

8.7

5.1
28 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003 Continued

12331500-FLINT CREEK NEAR DRUMMOND, MONT.

Date

AUG 2003 

26... 

SEP 

22...

Streamflow, pH, Specific Temper- Hardness, n . . .' K . . t ,... , Calcium, 

_. mstan- onsite conduct- ature, filtered ,. u , Time x . , , , ., x , filtered taneous (standard ance, onsite water (mg/Las , .. .

(tf/s) units) (fiS/cm) (°C) CaC03 ) |mg/ '

0855 

1110

26 

46

8.3 529 

8.5 484

12.5 250 

9.5 230

70.0 

62.3

Magnesium, 

filtered 

(mg/L)

19.0

17.7

Arsenic, 

filtered

wu

11.3 

8.5

Date

AUG 2003 

26... 

SEP

22...

Arsenic, 

unfiltered 

recoverable 

(fig/L)

13 

10

Cadmium, 

filtered 

(fig/L)

<.04 

E.02

Cadmium, 

unfiltered 

recoverable 

(ng/L)

<.04 

E.02

n Copper, Copper, ,.,.K ' 

,. u . unfiltered filtered , . 

, , recoverable

(li9/LI ( M/D

1.3 2.1 

1.1 2.1

Iron, 

filtered 

(ng/L)

18 

9

Iron, 

unfiltered 

recoverable 

(jig/L)

90 

80

Lead, 

filtered 

(u.g/L)

.09 

E.06

Date

AUG 2003 

26... 

SEP 

22...

Lead, 

unfiltered 

recoverable 

(ng/L)

.65

.75

Manganese, 

filtered 

(ng/L)

89.9 

50.7

Manganese, 

unfiltered 

recoverable 

(ng/D

120

75

... Zinc, Zinc, .... . 

,. u , unfiltered filtered . . 

, .. , recoverable

IM/U (M/LI

1 3 

1 3

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

50 

94

Sediment, 

suspended 

(mg/L)

10

3

Sediment 

discharge, 

suspended 

(ton/d)

.70

.37
TABLE 4 29

Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2002 through September 2003 Continued

12331800--CLARK FORK NEAR DRUMMOND, MONT.

Date

MAR 2003

15...

APR

03...

29...

MAY

27...

JUN

03...

17...

JUL

29...

AUG

26...

Streamflow, pH, Specific Temper- Hardness, . . 

 1 j * * «-i+ ^ Calcium, T. mstan- onsite conduct- ature, filtered ,. u . Time , , * j j * *. i /i filtered taneous (standard ance, onsite water (mg/Las , ...

(frVs) units) (u,S/cm) (°C) CaC03 ) lmg/ '

1330

1025

0925

1225

0940

1020

1035

1055

2,290

1,020

1,180

2,310

2,540

969

232

238

7.9 309

8.4 437

8.3 331

8.1 237

8.1 258

8.3 370

8.3 555

8.3 589

3.0 110

5.5 190

7.0 140

13.0 100

11.0 110

17.5 160

19.5 260

17.0 280

32.2

54.7

41.8

30.8

33.8

46.6

75.1

77.9

Magnesium, 

filtered 

(mg/L)

7.52

12.8

9.73

6.68

7.31

11.1

18.0

19.7

Arsenic, 

filtered 

WL)

12.8

9.3

7.9

11.6

14.4

12.1

14.0

11.4

Date

MAR 2003

15...

APR

03...

29...

MAY

27...

JUN

03...

17...

JUL

29...

AUG

26...

Arsenic, 

unfiltered 

recoverable 

(jig/L)

37

14

12

32

27

14

13

14

Cadmium, 

filtered 

(ng/L)

.14

.07

.05

.05

.10

.06

E.03

E.03

Cadmium, 

unfiltered 

recoverable 

WD

1.17

.22

.20

.89

.54

.16

.04

.08

Copper, 

filtered 

(ng/L)

19.6

7.0

4.9

10.8

12.6

7.1

4.7

3.7

Copper, 

unfiltered 

recoverable 

(M/L)

215

42.1

28.6

145

105

21.5

7.2

9.4

Iron, 

filtered 

(M/L)

88

17

18

40

39

10

<8

<8

Iron, 

unfiltered 

recoverable 

(fxg/L)

5,770

780

750

-

2,130

350

40

130

Lead, 

filtered 

WL)

.66

.19

.11

.39

.42

E.06

<08

<.08

Date

MAR 2003

15...

APR

03...

29...

MAY

27...

JUN

03...

17...

JUL

29...

AUG

26...

Lead, 

unfiltered 

recoverable 

H/L)

43.9

6.86

4.95

26.1

17.5

2.89

.34

.98

Manganese, 

filtered 

(fig/L)

38.4

27.5

16.0

15.7

16.4

19.7

9.9

10.4

Manganese, 

unfiltered 

recoverable

wu

570

118

96

420

264

70

26

79

Zinc, 

filtered 

(ng/L)

13

7

3

4

9

5

3

3

Zinc, 

unfiltered 

recoverable 

(fxg/L)

276

50

38

211

121

25

6

12

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

68

62

66

63

65

78

87

58

Sediment, 

suspended 

(mg/L)

294

46

45

224

133

17

3

18

Sediment 

discharge, 

suspended 

(ton/d)

1,820

127

143

1,400

912

44

1.9

12
30 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003 Continued

12334510--ROCK CREEK NEAR CLINTON, MONT.

Date

AUG 2003 

26... 

SEP

22...

Streamf ow, pH, Specific Temper- Hardness, . . 

 1 j * * *-i* j Calcium, T. mstan- onsite conduct- ature, filtered .... , Time . , . , , .. . , .. filtered taneous (standard ance, onsite water (mg/L as , ...

(frVs) units) (jxS/cm) (°C) CaC03 ) (mg/ '

1120 

1245

206 8.2 152 

195 8.4 160

14.5 73 

10.5 74

18.5 

19.0

Magnesium, 

filtered 

(mg/L)

6.58 

6.39

Arsenic, 

filtered 

(ng/L)

.7 

.7

Date

AUG 2003 

26... 

SEP

22...

Arsenic, 

unfiltered 

recoverable 

(ixg/L)

El

<2

_ . . Cadmium, Cadmium, ,. |JL , 

,.. , unfiltered filtered , . 

. .. . recoverable (ng/L) , /n (pig/L)

<.04 <.04 

<.04 <.04

n Copper, Copper, ,.,/ . 

,.. , unfiltered filtered . . 

, . recoverable

(uQ/L) , .

(i^g/L)

.4 .8 

.3 E.6

Iron, 

filtered 

(fig/L)

10 

E6

Iron, 

unfiltered 

recoverable 

(W/L)

40 

30

Lead, 

filtered 

(ng/L)

<08 

<.08

Date

AUG 2003 

26... 

SEP

22...

Lead, 

unfiltered 

recoverable 

(ng/D

<.06 

E.03

.. Manganese, Manganese, " . ,..f , unfiltered filtered . . 

, . recoverable

\ M-y/ M / « /i \

(M-g/L)

2.0 5 

1.7 4

... Zinc, Zinc, .... . 

,.u . unfiltered filtered . . 

, ... recoverable

<1 <2 

<1 <2

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

80 

82

Sediment, 

suspended 

(mg/L)

2 

1

Sediment 

discharge, 

suspended 

(ton/d)

1.1

.53
TABLE 4 31

Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2002 through September 2003 Continued

12334550--CLARK FORK ATTURAH BRIDGE, NEAR BONNER, MONT.

Date

MAR 2003

16...

APR

03...

29...

MAY

27...

*29...

*30...

*31...

JUN

*01...

02...

*02...

17...

JUL

29...

AUG

26...

Streamflow, pH, Specific Temper- Hardness, » . MagneT. instan- onsite conduct- ature, filtered ,. u ' sium, Time ^ / * j j *. .11, filtered ,..,. ' taneous (standard ance, onsite water (mg/Las , ... filtered

(ftVs) units) (nS/cm) (°C) CaC03) (mg/ ' (mg/L)

0850

1350

1140

1615

1300

1345

1000

1330

0820

1530

0840

1215

1300

2,440

1,620

2,300

5,780

5,810

6,820

6,700

6,430

6,200

5,950

2,320

590

476

8.1 308

8.5 318

8.3 236

8.0 139

8.0 148

7.8 141

7.8 138

7.7 149

8.0 156

7.8 159

8.2 226

8.5 316

8.6 360

4.0 130

6.0 140

6.5 100

12.0 54

14.0 69

13.5 60

11.0 61

13.0 64

11.5 68

13.0 68

15.0 96

18.5 140

17.5 160

37.1

39.0

29.1

14.9

18.8

17.4

17.5

18.6

19.8

19.5

26.6

39.8

42.7

8.95

9.89

7.42

3.97

5.28

4.07

4.18

4.35

4.60

4.66

7.15

10.6

12.3

Arsenic, 

filtered 

(lig/L)

10.3

6.1

4.8

5.6

3.5

7.0

7.0

8.0

7.8

8.1

5.8

5.8

5.6

Date

MAR 2003

15...

APR

03...

29...

MAY

27...

*29...

*30...

*31...

JUN

*01...

02...

*02...

17...

JUL

29...

AUG

26...

Arsenic, 

unfiltered 

recoverable 

(ng/L)

21

8

7

13

7

14

16

15

15

13

7

6

7

Cadmium, 

filtered 

(ng/L)

.07

.04

E.03

.04

E.03

.06

.05

.06

.05

.06

.04

E.02

<.04

Cadmium, 

unfiltered 

recoverable

.56

.16

.12

.53

.24

.46

.56

.45

.38

.27

.10

E.03

E.03

_ Copper, Copper, ,.,A , 

,...KK ' unfiltered filtered , . 

, . recoverable (^g/L) / /! v (^g/L)

11.6 104

5.1 25.3

3.8 17.6

6.5 68.8

4.1 34.2

9.2 73.1

9.8 79.3

11.3 73.7

9.0 64.0

10.2 53.1

4.0 12.1

2.4 3.7

2.4 4.3

Iron, 

filtered

57

28

29

62

31

54

61

51

58

39

17

<8

<8

Iron, 

unfiltered 

recoverable 

(ng/L)

2,460

580

530

2,680

1,470

2,720

2,910

2,380

1,840

1,560

270

150

40

Lead, 

filtered 

(ng/L)

.33

.16

.10

.31

.22

.30

.33

.31

.35

.28

E.04

<.08

<.08
32 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003 Continued

12334550--CLARK FORK ATTURAH BRIDGE, NEAR BONNER, MONT. Continued

Date

MAR 2003

15...

APR

03...

29...

MAY

27...

*29...

*30...

*31...

JUN

*01...

02...

*02...

17...

JUL

29...

AUG

26...

Lead, 

unfiltered 

recoverable 

(|^g/L)

17.5

4.02

3.19

14.9

6.52

14.2

15.8

14.0

10.8

9.33

1.54

.18

.21

Manganese, 

filtered 

(fig/L)

14.6

10.1

6.4

15.4

2.1

2.0

2.4

2.3

10.2

2.3

12.8

5.4

4.1

Manganese, 

unfiltered 

recoverable 

(ng/D

278

69

58

248

126

247

278

231

186

153

39

13

16

Zinc, 

filtered 

(ng/L)

9

3

2

2

4

6

8

6

6

6

4

1

2

Zinc, 

unfiltered 

recoverable 

(ng/L)

135

35

27

121

62

118

143

115

88

75

16

4

4

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

78

77

68

55

-

-

-

--

64

-

66

84

90

Sediment, 

suspended 

(mg/L)

131

30

31

218

316

295

281

222

134

146

16

3

3

Sediment 

discharge, 

suspended 

(ton/d)

863

131

193

3,400

4,960

5,430

5,080

3,850

2,240

2,350

100

4.8

3.9

*Supplemental samples collected by observer during high flow. Samples were collected by depth integration at a single vertical near midstream.
TABLE 4 33

Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2002 through September 2003 Continued

12340000--BLACKFOOT RIVER NEAR BONNER, MONT.

Date

AUG 2003 

26... 

SEP 

22...

Streamflow, pH, Specific Temper- Hardness, . . 

 x -x jx * t-u j Calcium, T. mstan- onsite conduct- ature, filtered ,. u . Time , , , . . .4 , , filtered taneous (standard ance, onsite water (mg/L as , ...

(ftVs) units) (M-S/cm) (°C) CaC03) |m9/L)

1440 

1425

512 8.6 268 

489 8.6 271

18.0 140 

12.5 140

33.8 

34.3

Magnesium, 

filtered 

(mg/L)

13.0 

12.8

Arsenic, 

filtered 

(W/L)

1.4 

1.2

Date

AUG 2003 

26... 

SEP 

22...

Arsenic, 

unfiltered 

recoverable 

WU

E2 

El

n , . Cadmium, Cadmium, ,... . 

,. u . unfiltered filtered , . 

, .. . recoverable

{WI/L| (HA)

<.04 <.04 

<.04 <.04

n Copper, Copper, ,.;! . 

,.. ' unfiltered filtered . . 

, , recoverable (ng/L) . ,. .

(ng/L)

.5 E.6 

.4 .6

Iron, 

filtered 

(ng/D

E4 

<8

Iron, 

unfiltered 

recoverable

20 

10

Lead, 

filtered 

(MI/L)

<.08 

<.08

Date

AUG 2003 

26... 

SEP

22...

Lead, 

unfiltered 

recoverable 

(fig/L)

<.06 

<.06

., Manganese, Manganese, ,^ . ,..f . unfiltered filtered , , 

, .. . recoverable (ng/L) , ... (M^g/D

1.4 4 

1.1 3

.,. Zinc, Zinc, ,. u , 

,.. ' unfiltered filtered , , 

. , recoverable

<1 <2

3 <2

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

79 

82

Sediment, 

suspended 

(mg/L)

i 

i

Sediment 

discharge, 

suspended 

(ton/d)

1.4 

1.3
34 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003 Continued

12340500-CLARK FORK ABOVE MISSOULA, MONT.

Date

MAR 2003

15...

APR

04...

29...

MAY

28...

*29...

*30...

*31...

JUN

*01...

02...

*02...

17...

JUL

29...

AUG

26...

Streamflow, pH, Specific Temper- Hardness, 

instan- Onsite conduct- ature, filtered 

taneous (standard ance,onsite water (mg/L as 

(ft3/s) units) (^iS/cm) (°C) CaC03 )

1540

0800

1350

0910

1215

1300

1100

1230

0945

1400

0720

1335

1600

5,140

3,290

6,150

12,800

13,500

14,700

15,100

14,700

13,500

13,400

5,470

1,280

999

7.9

8.3

8.3

8.0

7.9

7.9

7.9

7.8

8.1

7.8

8.3

8.6

8.5

233

271

193

148

140

147

145

151

156

159

200

278

311

4.0

5.0

7.0

12.0

14.0

13.0

11.0

11.5

11.5

12.0

15.5

21.0

19.5

93

120

89

71

61

67

67

69

74

73

91

130

150

Calcium, 

filtered 

(mg/L)

25.9

32.2

23.9

19.4

17.6

18.6

18.6

19.1

20.7

20.3

23.8

34.6

38.0

Magnesium, 

filtered 

(mg/L)

6.78

9.15

7.07

5.34

4.25

5.01

5.06

5.11

5.54

5.54

7.57

10.9

12.7

Arsenic, 

filtered 

WU

9.0

3.6

2.3

3.4

6.2

4.0

4.2

4.8

4.6

4.8

3.3

4.0

3.6

Date

MAR 2003

15...

APR

04...

29...

MAY

28...

*29...

*30...

*31...

JUN

*01...

02...

*02...

17...

JUL

29...

AUG

26...

Arsenic, 

unfiltered 

recoverable 

WD

19

5

3

8

13

7

9

9

9

9

4

4

4

Cadmium, 

filtered 

WD

.08

E.02

E.02

E.02

.04

E.03

.04

E.03

E.03

.05

E.02

<.04

<.04

Cadmium, 

unfiltered 

recoverable 

WL)

.64

.11

.09

.27

.40

.20

.29

.29

.32

.22

.07

E.02

E.03

Copper, 

filtered 

WL)

12.6

3.4

2.3

3.8

7.6

4.9

5.0

6.2

5.1

5.7

2.8

1.9

2.0

Copper, 

unfiltered 

recoverable 

WU

107

18.6

10.5

39.8

68.0

35.4

45.7

46.1

46.0

36.9

8.5

3.5

4.3

Iron, 

filtered 

WL)

77

47

26

40

49

32

38

34

41

26

13

<8

E5

Iron, 

unfiltered 

recoverable 

WL)

3,040

490

420

1,680

2,430

1,610

1,910

1,740

1,480

1,320

230

70

70

Lead, 

filtered 

WL)

.34

.15

.08

.17

.29

.17

.23

.20

.22

.17

<.08

<.08

<.08
TABLE 4 35

Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 2002 through September 2003 Continued

12340500--CLARK FORK ABOVE MISSOULA, MONT. Continued

Date

MAR 2003

15...

APR

04...

29...

MAY

28...

*29...

*30...

*31...

JUN

*01...

02...

*02...

17...

JUL

29...

AUG

26...

Lead, 

unfiltered 

recoverable 

(ng/L)

17.8

2.97

1.78

7.50

12.8

6.87

9.14

8.65

7.93

6.72

1.17

.32

.39

Manganese, 

filtered

wu

21.2

22.6

13.2

13.2

3.1

1.6

2.0

1.9

14.2

1.7

13.5

15.9

14.5

Manganese, 

unfiltered 

recoverable 

(Ml/L)

314

53

42

143

218

136

157

154

137

119

33

28

28

Zinc, 

filtered

wu

8

3

1

1

4

3

8

6

4

4

3

1

1

Zinc, 

unfiltered 

recoverable 

H/L)

155

28

16

77

105

68

85

81

79

64

12

4

5

Sediment, 

suspended, 

percent 

finer than 

0.062 mm

85

82

85

75

--

-

-

-

68

-

89

82

89

Sediment, 

suspended 

(mg/L)

169

26

29

137

137

169

174

168

123

122

14

5

3

Sediment 

discharge, 

suspended 

(ton/d)

2,350

231

482

4,730

4,990

6,710

7,090

6,670

4,480

4,410

207

17

8.1

''Supplemental samples collected by observer during high flow. Samples were collected by depth integration at a single vertical near midstream.
36 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 2003

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

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(frVs)

134

141

170

173

172

168

165

159

161

160

164

160

155

152

148

152

154

152

156

156

161

159

153

152

158

166

168

172

169

139

e!20

4,869

157

173

120

Suspended sediment

Mean 

concentration 

(mg/L)

OCTOBER

10

18

38

37

37

37

37

37

37

37

37

35

32

30

29

29

27

25

22

20

20

19

18

17

16

16

16

16

16

16

18

26

38

10

Discharge 

(ton/d)

3.6

6.9

17

17

17

17

16

16

16

16

16

15

13

12

12

12

11

10

9.3

8.4

8.7

8.2

7.4

7.0

6.8

7.2

7.3

7.4

7.3

6.0

5.8

340.3

11

17

3.6

Mean 

streamflow 

(ft3/s)

ellO

el!5

e!25

e!35

e!60

e!80

205

218

220

220

201

198

213

213

205

198

197

193

189

191

191

191

205

e!70

e!50

e!60

e!70

e!80

e!90

203

-

5,496

183

220

110

Suspended sediment

Mean 

concentration 

(mg/L)

NOVEMBER

19

18

17

16

15

16

16

17

18

18

19

21

24

25

24

21

18

15

15

16

18

18

19

19

19

20

20

20

20

20

-

-.

19

25

15

Discharge 

(ton/d)

5.6

5.6

5.7

5.8

6.5

7.8

8.9

10

11

11

10

11

14

14

13

11

9.6

7.8

7.7

8.3

9.3

9.3

11

8.7

7.7

8.6

9.2

9.7

10

11

-

278.8

9.3

14

5.6

Mean 

streamflow 

(ftVs)

199

199

199

199

202

201

e!70

e!60

e!60

e!70

e!80

190

196

210

236

218

204

173

e!60

e!60

177

181

179

e!50

el 30

e!40

e!50

189

192

178

190

5,642

182

236

130

Suspended sediment

Mean 

concentration 

(mg/L)

DECEMBER

20

22

26

29

29

27

25

24

23

24

26

27

25

23

21

20

19

21

25

27

26

23

20

18

17

20

27

30

29

28

27

..

24

30

17

Discharge 

(ton/d)

11

12

14

16

16

15

11

10

9.9

11

13

14

13

13

13

12

10

9.8

11

12

12

11

9.7

7.3

6.0

7.6

11

15

15

13

14

368.3

12

16

6.0
TABLE 5 37

Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 2002 through September 

2003 Continued

Suspended sediment

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(frVs)

186

187

199

207

219

199

180

e!70

e!50

e!40

e!30

e!40

185

186

188

172

e!60

e!70

e!80

193

e!50

e!30

e!60

227

202

249

520

315

266

262

311

6,333

204

520

130

Mean 

concentration 

(mg/L)

JANUARY

26

24

23

21

20

18

16

15

13

12

13

16

18

19

18

16

15

15

16

16

17

18

28

38

41

66

300

87

51

44

42

35

300

12

Discharge 

(ton/d)

13

12

12

12

12

9.7

7.8

6.9

5.3

4.5

4.6

6.0

9.0

9.5

9.1

7.4

6.5

6.9

7.8

8.3

6.9

6.3

12

23

22

44

421

74

37

31

35

882.5

28

421

4.5

Mean 

streamflow 

(ftS/s)

416

353

287

269

250

229

201

223

220

214

200

197

191

196

191

191

192

189

178

179

179

196

e!40

elOO

e!20

e!40

e!60

e!70

--

-

--

5,771

206

416

100

Suspended sediment

Mean 

concentration 

(mg/L)

FEBRUARY

50

45

40

37

32

29

27

28

28

28

32

35

29

23

23

26

29

31

32

32

32

31

31

38

48

57

52

52

--

--

-

35

57

23

Discharge 

(ton/d)

56

43

31

27

22

18

15

17

17

16

17

19

15

12

12

13

15

16

15

15

15

16

12

10

16

22

22

24

--

-

-

548

20

56

10

Mean 

streamflow 

(ft3/*)

165

176

177

176

189

186

186

188

189

242

417

601

661

634

589

560

481

344

283

245

237

233

237

228

214

218

217

217

213

208

210

9,121

294

661

165

Suspended sediment

Mean 

concentration 

(mg/L)

MARCH

55

55

31

34

39

38

33

34

37

59

170

252

197

127

163

104

45

51

43

47

33

32

28

27

26

24

19

17

22

24

22

61

252

17

Discharge 

(ton/d)

25

26

15

16

20

19

17

17

19

39

191

409

352

217

259

157

58

47

33

31

21

20

18

17

15

14

11

10

13

13

12

2,131

69

409

10
38 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through September 

2003 Continued

Day

l

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

Suspended sediment

Mean Mean 

streamflow concen. Discharge 

(ft /s) tration (ton/d) 

(mg/L)

APRIL

283

330

343

312

280

263

248

240

234

218

219

228

234

253

256

242

232

232

223

202

195

197

237

300

312

338

313

285

289

335

--

7,873

262

343

195

Suspended sediment

Mean Mean 

streamflow concen. Discharge 

(ft /s) tration (ton/d) 

(mg/L)

MAY

323

322

312

361

452

424

400

356

324

301

291

286

277

267

268

270

275

274

271

247

234

215

201

234

303

428

526

607

722

818

961

11,550

373

961

201

Suspended sediment

Mean Mean 

streamflow concen. 

(fr/s) tration

(mg/L)

JUNE

1,020

968

806

650

555

471

424

374

370

381

449

426

367

390

364

339

326

318

309

350

413

374

337

311

285

258

241

230

231

219

--

12,556

419

1,020

219

Discharge 

(ton/d)

-

-

--

--

--

--

-

--

--

--

--

--

--

_

--

-

-

--

._

-

--

--

--

._

--

--

-

-

--

-

--

--
TABLE 5 39

Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 2002 through September 

2003 Continued

Day

l

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

Suspended sediment

Mean Mean 

streamflow concen. Discharge 

(fr/s) tration (ton/d) 

(mg/L)

JULY

198

190

182

169

161

154

148

137

138

120

104

92

86

84

75

65

59

55

54

56

53

48

44

42

40

42

45

46

40

38

36

2,801

90.4

198

36

Suspended sediment

Mean 

streamflow 

(frVs)

38

37

37

40

45

45

52

53

51

46

43

45

49

49

49

49

45

57

64

62

63

63

85

81

81

74

76

88

85

94

95

1,841

59.4

95

37

Mean 

concentration 

(mg/L)

AUGUST

3

4

4

7

9

10

10

11

11

10

9

9

10

12

13

14

14

16

15

11

11

11

11

12

14

13

10

10

10

10

10

10

16

3

Discharge 

(ton/d)

.31

.40

.40

.76

1.1

1.2

1.4

1.6

1.5

1.2

1.0

1.1

1.3

1.6

1.7

1.9

1.7

2.5

2.6

1.8

1.9

1.9

2.5

2.6

3.1

2.6

2.1

2.4

2.3

2.5

2.6

53.57

1.7

3.1

.31

Mean 

streamflow 

(tf/s)

92

89

86

88

87

88

92

93

87

88

88

87

91

94

94

93

106

114

109

104

109

107

111

113

137

130

117

114

112

111

--

3,031

101

137

86

Suspended sediment

Mean 

concentration 

(mg/L)

SEPTEMBER

10

10

10

10

10

10

10

8

8

8

8

9

9

9

9

8

10

16

19

20

19

20

20

20

20

21

21

22

22

23

--

14

23

8

Discharge 

(ton/d)

2.5

2.4

2.3

2.4

2.3

2.4

2.5

2.0

1.9

1.9

1.9

2.1

2.2

2.3

2.3

2.0

2.9

4.9

5.6

5.6

5.6

5.8

6.0

6.1

7.4

7.4

6.6

6.8

6.7

6.9

-

119.7

4.0

7.4

1.9

TOTAL FOR WATER YEAR 2003:

STREAMFLOW-76,884 ft3/s

SEDIMENT LOAD-4,722.17 tons (partial year)
40 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through 

September 2003

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

Suspended sediment

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)

642

639

641

661

664

669

683

674

671

698

703

717

712

715

721

721

723

725

715

708

702

699

710

715

708

690

707

729

e750

e700

e650

21,562

696

750

639

Mean 

concentration 

(mg/L)

OCTOBER

2

3

4

4

5

6

6

6

6

6

6

6

6

6

6

7

7

7

7

6

6

6

6

6

6

6

6

6

7

7

7

6

7

2

Discharge 

(ton/d)

3.5

5.2

6.9

7.1

9.0

11

11

11

11

11

11

12

12

12

12

14

14

14

14

11

11

11

12

12

11

11

11

12

14

13

12

342.7

11

14

3.5

Mean 

streamflow 

IffVs)

e600

e600

e600

649

677

702

741

768

775

764

765

749

765

779

770

756

754

746

737

736

742

748

776

e700

e600

624

658

678

703

722

-

21,384

713

779

600

Suspended sediment

Mean 

concentration 

(mg/L)

NOVEMBER

7

7

8

8

8

9

10

10

10

10

9

9

9

9

8

8

8

8

7

7

7

7

8

9

9

9

8

7

7

7

--

8

10

7

Discharge 

(ton/d)

11

11

13

14

15

17

20

21

21

21

19

18

19

19

17

16

16

16

14

14

14

14

17

17

15

15

14

13

13

14

--

478

16

21

11

Mean 

streamflow 

(ft-Vs)

692

691

736

722

714

705

671

e600

593

582

627

654

657

720

704

700

696

638

e550

541

605

614

607

593

535

494

558

651

657

592

601

19,700

635

736

494

Suspended sediment

Mean 

concentration 

(mg/L)

DECEMBER

7

7

7

7

7

7

6

6

7

8

8

8

8

9

9

8

5

3

2

3

4

6

6

5

4

4

6

9

9

8

6

..

6

9

2

Discharge 

(ton/d)

13

13

14

14

13

13

11

9.7

11

13

14

14

14

17

17

15

9.4

5.2

3.0

4.4

6.5

9.9

9.8

8.0

5.8

5.3

9.0

16

16

13

9.7

346.7

11

17

3.0
TABLE 6 41

Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 2002 through 

September 2003 Continued

Day

l

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/*)

640

599

651

651

663

636

573

e550

537

e500

e450

e500

609

711

662

609

e550

490

502

585

e550

e450

e400

e500

585

680

1,530

1,840

1,080

904

1,070

21,257

686

1,840

400

Suspended sediment

Mean 

concentration 

(mg/L)

JANUARY

6

6

5

5

5

5

5

4

4

4

4

3

11

16

9

5

4

4

5

5

5

6

5

5

7

10

186

230

85

35

72

._

25

230

3

Discharge 

(ton/d)

10

9.7

8.8

8.8

9.0

8.6

7.7

5.9

5.8

5.4

4.9

4.0

18

31

16

8.2

5.9

5.3

6.8

7.9

7.4

7.3

5.4

6.8

11

18

768

1,140

248

85

208

2,692.6

87

1,140

4.0

Mean 

streamflow 

(frVs)

2,150

1,820

1,240

1,040

943

e850

e750

766

804

792

758

713

686

723

738

718

722

708

691

679

687

727

e650

e400

e350

e450

e500

578

--

--

--

22,633

808

2,150

350

Suspended sediment

Mean 

concentration 

(mg/L)

FEBRUARY

244

109

39

21

17

15

14

12

11

11

11

11

10

10

10

12

14

11

8

7

7

7

7

7

7

7

6

7

--

--

-

23

244

6

Discharge 

(ton/d)

1,420

536

131

59

43

34

28

25

24

24

23

21

19

20

20

23

27

21

15

13

13

14

12

7.6

6.6

8.5

8.1

11

-

~

--

2,606.8

93

1,420

6.6

Mean 

streamflow 

(frVs)

643

648

e650

e650

e650

650

676

e650

e700

749

850

1,150

2,600

4,620

3,400

2,410

2,280

1,780

1,510

1,360

1,320

1,280

1,410

1,430

1,270

1,220

1,180

1,120

1,090

1,070

1,200

42,216

1,362

4,620

643

Suspended sediment

Mean 

concentration 

(mg/L)

MARCH

9

8

6

8

5

5

6

4

5

10

16

75

380

790

323

141

112

64

41

31

25

23

34

42

19

16

15

14

14

15

18

-

73

790

4

Discharge 

(ton/d)

16

14

11

14

8.8

8.8

11

7.0

9.5

20

37

233

2,670

9,850

2,970

917

689

308

167

114

89

79

129

162

65

53

48

42

41

43

58

18,884.1

609

9,850

7.0
42 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through 

September 2003 Continued

Day

1

2

3

4

5

6

1

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

Suspended sediment

Mean Mean

streamflow concen- Discharge 

(fr/s) tratjon (ton/d)

(mg/L)

APRIL

1,520

1,650

1,600

1,510

1,410

1,360

1,310

1,250

1,250

1,360

1,530

1,720

1,940

2,180

2,220

2,110

1,950

1,870

1,810

1,720

1,700

1,760

1,990

2,390

2,730

2,970

2,730

2,510

2,340

2,370

--

56,760

1,892

2,970

1,250

Suspended sediment

Mean Mean 

streamflow conce n- Discharge 

(fr/s) tratj on (ton/d )

(mg/L)

MAY

2,400

2,410

2,420

2,520

2,930

2,940

2,760

2,670

2,560

2,430

2,300

2,270

2,300

2,280

2,350

2,610

2,770

2,680

2,590

2,400

2,210

2,130

2,240

2,710

3,790

5,200

5,830 205 3,230

5,680 272 4,170

5,910 311 4,960

6,590 300 5,340

6,790 276 5,060

99,670

3,215

6,790

2,130

Suspended sediment

Mean Mean 

streamflow concen.

( tration 

(mg/L)

JUNE

6,430 227

5,950 141

5,210

4,590

3,960

3,560

3,270

3,080

2,980

2,980

3,200

2,990

2,810

2,700

2,610

2,500

2,370

2,240

2,120

2,190

2,450

2,360

2,160

1,980

1,850

1,720

1,600

1,490

1,430

1,360

--

86,140

2,871

6,430

1,360

Discharge 

(ton/d)

3,940

2,270

--

--

--

-

--

-

--

-

-

-

--

--

--

--

-

--

--

-

-

--

--

--

--

--

--

--

--

--
TABLE 6 43

Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 2002 through 

September 2003 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

Suspended sediment

Mean Mean

streamflow conce n- Discharge 

(fr/s) tratjon (ton/d )

(mg/L)

JULY

1,280

1,200

1,160

1,130

1,080

1,040

987

985

1,100

1,030

963

911

903

926

927

892

852

754

746

734

688

674

657

641

655

661

647

637

597

561

532 4 5.7

26,550

856

1,280

532

Suspended sediment

Mean 

streamflow 

(ft3/s)

501

487

484

499

498

488

501

496

509

495

483

466

480

463

432

439

441

448

458

480

460

453

495

519

502

475

475

480

472

470

468

14,817

478

519

432

Mean 

concentration 

(mg/L)

AUGUST

4

4

4

4

4

4

4

4

3

3

3

3

3

3

3

3

3

3

3

3

3

3

4

5

4

3

3

4

6

8

11

4

11

3

Discharge 

(ton/d)

5.4

5.3

5.2

5.4

5.4

5.3

5.4

5.4

4.1

4.0

3.9

3.8

3.9

3.8

3.5

3.6

3.6

3.6

3.7

3.9

3.7

3.7

5.3

7.0

5.4

3.8

3.8

5.2

7.6

10

14

157.7

5.1

14

3.5

Mean 

streamflow 

(tf/s)

479

468

452

448

443

448

454

462

477

471

463

503

514

506

503

510

523

545

553

550

538

534

539

527

522

518

508

504

505

507

--

14,974

499

553

443

Suspended sediment

Mean 

concentration 

(mg/L)

SEPTEMBER

14

11

7

4

4

3

5

6

6

5

4

6

5

5

6

6

6

6

7

7

7

7

7

7

6

6

6

6

6

6

--

6

14

3

Discharge 

(ton/d)

18

14

8.5

4.8

4.8

3.6

6.1

7.5

7.7

6.4

5.0

8.1

6.9

6.8

8.1

8.3

8.5

8.8

10

10

10

10

10

10

8.5

8.4

8.2

8.2

8.2

8.2

--

251.6

8.4

18

3.6

TOTAL FOR WATER YEAR 2003:

STREAMFLOW-447,663 ft3/s

SEDIMENT LOAD--54J35.9 tons (partial year)
44 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through 

September 2003

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

Suspended sediment

Day

l

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)

1,180

1,130

1,130

1,150

1,160

1,150

1,170

1,160

1,150

1,160

1,160

1,180

1,180

1,190

1,180

1,180

1,170

1,180

1,180

1,160

1,160

1,150

1,140

1,170

1,110

1,130

1,140

1,160

1,190

1,130

986

35,766

1,154

1,190

986

Mean 

concentration 

(mg/L)

OCTOBER

8

6

6

6

7

8

8

7

7

7

7

6

6

5

5

6

6

6

6

7

7

6

6

5

5

4

4

5

5

5

4

6

8

4

Discharge 

(ton/d)

25

18

18

19

22

25

25

22

22

22

22

19

19

16

16

19

19

19

19

22

22

19

18

16

15

12

12

16

16

15

11

580

19

25

11

Mean 

streamflow 

(ft3/s)

942

1,040

1,160

1,150

1,200

1,190

1,190

1,260

1,270

1,260

1,230

1,210

1,210

1,230

1,220

1,190

1,170

1,170

1,170

1,160

1,180

1,190

1,230

1,250

1,090

1,050

1,090

1,080

1,090

1,140

~

35,012

1,167

1,270

942

Suspended sediment

Mean 

concentration 

(mg/L)

NOVEMBER

4

4

4

4

4

4

5

8

10

9

8

7

6

6

6

5

6

7

8

10

9

8

7

6

5

5

5

4

4

4

--

6

10

4

Discharge 

(ton/d)

10

11

13

12

13

13

16

27

34

31

27

23

20

20

20

16

19

22

25

31

29

26

23

20

15

14

15

12

12

12

--

581

19

34

10

Mean 

streamflow 

(ffVs)

1,110

1,100

1,100

1,100

1,070

1,120

1,090

1,010

953

927

1,010

1,090

1,090

1,140

1,090

1,120

1,100

1,060

916

862

e900

1,020

1,040

999

948

913

969

1,090

1,110

1,030

972

32,049

1,034

1,140

862

Suspended sediment

Mean 

concentration 

(mg/L)

DECEMBER

4

4

10

5

8

6

4

4

4

3

3

3

4

9

8

5

4

3

2

2

2

3

3

3

3

4

3

3

3

3

3

4

10

2

Discharge 

(ton/d)

12

12

30

15

23

18

12

11

10

7.5

8.2

8.8

12

28

24

15

12

8.6

4.9

4.7

4.9

8.3

8.4

8.1

7.7

9.9

7.8

8.8

9.0

8.3

7.9

365.8

12

30

4.7
TABLE 7 45

Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana October 2002 through 

September 2003 Continued

Day

l

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(tf/s)

1,050

1,020

1,060

1,080

1,070

1,060

995

902

e800

e700

e750

877

1,070

1,190

1,110

1,040

859

797

835

954

1,020

843

737

772

1,020

1,180

1,820

2,550

1,530

1,420

1,610

33,721

1,088

2,550

700

Suspended sediment

Mean 

concentration 

(mg/L)

JANUARY

3

4

3

3

3

3

4

5

4

4

3

4

5

5

4

3

2

3

3

4

4

5

68

8

11

15

66

170

47

19

20

-.

16

170

2

Discharge 

(ton/d)

8.5

11

8.6

8.7

8.7

8.6

11

12

8.6

7.6

6.1

9.5

14

16

12

8.4

4.6

6.5

6.8

10

11

11

135

17

30

48

324

1,170

194

73

87

2,287.2

74

1,170

4.6

Mean 

streamflow 

(ft3/s)

3,130

3,090

2,200

1,760

1,580

1,430

1,290

1,290

1,310

1,320

1,200

1,160

1,130

1,160

1,190

1,160

1,170

1,160

1,130

1,120

1,120

1,180

1,090

769

677

846

946

1,050

--

-

-

37,658

1,345

3,130

677

Suspended sediment

Mean 

concentration 

(mg/L)

FEBRUARY

161

88

26

16

11

9

7

7

7

6

5

5

5

6

7

8

9

9

10

8

7

6

5

4

3

3

4

5

--

-

--

-

16

161

3

Discharge 

(ton/d)

1,360

734

154

76

47

35

24

24

25

21

16

16

15

19

22

25

28

28

31

24

21

19

15

8.3

5.5

6.9

10

14

-

--

--

2,823.7

101

1,360

5.5

Mean 

streamflow 

(ftVs)

1,130

1,130

1,100

1,060

1,050

1,080

1,110

1,050

1,000

1,160

1,390

1,680

3,430

5,740

5,170

3,900

3,940

3,180

2,620

2,370

2,300

2,280

2,580

2,730

2,430

2,310

2,230

2,110

2,000

2,000

2,200

69,460

2,241

5,740

1,000

Suspended sediment

Mean 

concentration 

(mg/L)

MARCH

3

3

4

4

3

5

6

3

3

7

9

20

188

372

160

82

63

53

40

22

20

20

23

27

19

16

15

14

14

15

16

--

40

372

3

Discharge 

(ton/d)

9.2

9.2

12

11

8.5

15

18

8.5

8.1

22

34

91

1,740

5,770

2,230

863

670

455

283

141

124

123

160

199

125

100

90

80

76

81

95

13,651.5

440

5,770

8.1
46 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2002 through 

September 2003 Continued

Day

l

2

3

4

5

6

1

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

Suspended sediment

Mean Mean 

streamflow concen. Discharge 

(ftVs) tration (ton/d) 

(mg/L)

APRIL

2,980

3,470

3,420

3,200

3,040

2,830

2,740

2,610

2,610

2,850

3,410

4,040

4,830

5,660

6,060

5,870

5,540

5,270

4,950

4,750

4,760

5,040

5,710

6,670

7,600

8,080

7,660

6,990

6,360

6,150

--

145,150

4,838

8,080

2,610

Suspended sediment

Mean Mean 

streamflow concen. Discharge 

(fr/s) tratjon (ton/d)

(mg/L)

MAY

5,980

5,880

5,890

5,990

6,620

6,670

6,370

6,040

5,700

e5,400

e5,200

e5,000

5,090

5,110

5,410

6,110

6,430

6,190

5,880

5,490

5,180

5,040

5,300

6,220

8,020

10,800

12,700

12,900 136 4,740

13,500 139 5,070

14,500 164 6,420

15,100 178 7,260

225,710

7,281

15,100

5,000

Suspended sediment

Mean Mean 

streamflow con cen- 

(fr/s) tratjon

(mg/L)

JUNE

14,900 169

13,500 124

11,900

10,400

9,160

8,200

7,570

7,090

6,910

6,980

7,130

6,950

6,350

6,100

5,950

5,680

5,400

5,140

4,980

5,080

5,420

5,140

4,720

4,340

4,070

3,870

3,560

3,390

3,200

3,060

--

196,140

6,538

14,900

3,060

Discharge 

(ton/d)

6,800

4,520

-

--

--

--

--

--

--

--

--

--

--

--

--

--

--

--

--

--

--

-

--

--

--

--

--

--

-
TABLE 7 47

Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 2002 through 

September 2003 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

Suspended sediment

Mean Mean 

streamflow concen. D jscharge 

(fr/s) tration (ton/d) 

(mg/L)

JULY

2,860

2,760

2,630

2,550

2,500

2,500

2,350

2,260

2,410

2,320

2,220

2,080

2,000

2,010

1,860

1,760

1,730

1,620

1,590

1,580

1,420

1,460

1,370

1,380

1,350

1,360

1,320

1,290

1,260 5 17

1,180 5 16

1,140 5 15

58,120

1,875

2,860

1,140

Mean 

streamflow 

(ft3/s)

1,090

1,090

1,080

1,070

1,090

1,090

1,110

1,110

1,210

1,190

1,120

1,090

1,070

1,050

995

914

905

933

1,010

995

974

963

1,000

1,060

1,050

1,010

990

994

1,000

986

972

32,211

1,039

1,210

905

Suspended sediment

Mean 

concentration 

(mg/L)

AUGUST

5

5

5

4

4

4

4

6

8

10

11

11

10

9

8

7

7

7

7

8

7

6

6

5

4

3

3

5

5

5

5

6

11

3

Discharge 

(ton/d)

15

15

15

12

12

12

12

18

26

32

33

32

29

26

21

17

17

18

19

21

18

16

16

14

11

8.2

8.0

13

14

13

13

546.2

18

33

8.0

Mean 

streamflow 

(tf/s)

984

979

960

941

933

927

927

950

962

972

964

1,010

1,090

1,080

1,050

1,050

1,070

1,090

1,100

1,080

1,050

1,040

1,040

1,030

1,020

1,040

1,020

999

996

989

--

30,343

1,011

1,100

927

Suspended sediment

Mean 

concentration 

(mg/L)

SEPTEMBER

5

5

5

5

5

5

5

6

8

8

7

6

6

6

5

5

5

5

5

5

5

5

5

7

8

8

8

8

7

7

--

6

8

5

Discharge 

(ton/d)

13

13

13

13

13

13

13

15

21

21

18

16

18

17

14

14

14

15

15

15

14

14

14

19

22

22

22

22

19

19

--

491

16

22

13

TOTAL FOR WATER YEAR 2003:

STREAMFLOW--931,340 ft3/s

SEDIMENT LOAD-56,184.4 tons (partial year)
48 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) and Statistical Summaries of Data for Streams 

in the upper Clark Fork Basin, Montana

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

[The terms "filtered" and "unfiltered recoverable" replace the former terms "dissolved" and "total recoverable," respectively. Abbreviations: E, 

estimated; (ig/L, micrograms per liter; mg/L, milligrams per liter; mm, millimeter. Symbol: <, less than analytical detection limit]

Station 

number Station name Date Time

12324200 Clark Fork at Deer Lodge 03-18-03 1215 

Clark Fork at Deer Lodge 03- 1 8-03 1 220

12323230 Blacktail Creek at Harrison Avenue, at Butte 04-02-03 0850 

Blacktail Creek at Harrison Avenue, at Butte 04-02-03 0855

12323750 Silver Bow Creek at Warm Springs 04-02-03 1435 

Silver Bow Creek at Warm Springs 04-02-03 1440

12334550 Clark Fork at Turah Bridge, near Bonner 04-29-03 1140 

Clark Fork at Turah Bridge, near Bonner 04-29-03 1145

12340500 Clark Fork above Missoula 05-28-03 0910 

Clark Fork above Missoula 05-28-03 0915

12323600 Silver Bow Creek at Opportunity 06-03-03 1430 

Silver Bow Creek at Opportunity 06-03-03 1435

12331800 Clark Fork near Drummond 08-26-03 1055 

Clark Fork near Drummond 08-26-03 1 100

Hard- .. Arsenic, 

ness. Calcium, . Arsenic, unfiltered 

filtered filtered ... ' filtered recov- 

(mg/Las (mg/L) ' er.® (ng/L) erable 

CaC03) lmg/L| (fxg/L)

220 

220

77 

78

200 

200

100 

100

71

72

130 

130

280 

280

64.6 

64.9

21.4 

21.6

58.6 

59.2

29.1 

29.1

19.4 

19.9

40.5 

40.6

77.9 

79.7

13.5 16.2 27 

13.8 16.3 27

5.66 4.4 6 

5.72 4.3 6

12.3 15.8 19 

12.3 16.1 20

7.42 4.8 7 

7.40 4.9 7

5.34 3.4 8 

5.47 3.4 8

7.25 9.5 14 

7.27 9.9 13

19.7 11.4 14 

20.1 11.6 14

Station 

number

12324200

12323230

12323750

12334550

12340500

12323600

12331800

Date

03-18-03

03-18-03

04-02-03

04-02-03

04-02-03

04-02-03

04-29-03

04-29-03

05-28-03

05-28-03

06-03-03

06-03-03

08-26-03

08-26-03

Cadmium, 

filtered 

(HO/L)

0.12

.12

.10

.06

.04

.04

E.03

E.03

E.02

E.02

.29

.30

E.03

E.02

Cadmium, 

unfiltered 

recoverable 

(M-g/D

0.41

.42

.11

.10

.11

.12

.12

.13

.27

.29

.58

.57

.08

.07

Copper, 

filtered 

(|ig/U

14.0

14.2

6.8

6.9

7.0

7.1

3.8

3.7

3.8

3.9

25.4

25.8

3.7

3.8

Copper, 

unfiltered 

recoverable 

(u.g/L)

95.8

89.6

16.9

16.5

18.4

18.4

17.6

17.7

39.8

40.6

60.6

60.6

9.4

9.1

Iron, 

filtered 

(lig/L)

12

13

312

314

15

16

29

26

40

38

38

40

<8

<8

Iron, 

unfiltered 

recoverable 

(u.g/D

1,420

1,370

1,450

1,430

340

350

530

510

1,680

1,720

620

610

130

130

Lead, 

filtered 

(ng/L)

0.25

.25

.62

.56

.14

.15

.10

.10

.17

.18

.27

.28

<.08

E.05
TABLE 8 49

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

Montana Continued

Station 

number

12324200

12323230

12323750

12334550

12340500

12323600

12331800

Date

03-18-03

03-18-03

04-02-03

04-02-03

04-02-03

04-02-03

04-29-03

04-29-03

05-28-03

05-28-03

06-03-03

06-03-03

08-26-03

08-26-03

Lead, 

unfiltered 

recoverable 

(ng/L)

22.1

20.9

4.86

4.76

5.13

5.05

3.19

2.97

7.50

7.45

10.2

10.3

.98

.93

Manganese, 

filtered 

(ng/L)

83.9

87.0

39.7

39.9

122

122

6.4

6.2

13.2

12.9

172

177

10.4

10.3

Manganese, 

unfiltered 

recoverable 

(MI/L)

259

253

72

71

172

151

58

58

143

146

211

211

79

77

Zinc, 

filtered 

(ng/U

19

20

8

7

7

7

2

2

1

1

40

40

3

3

Zinc, 

unfiltered 

recoverable 

(ng/L)

102

97

27

26

32

32

27

26

77

74

119

119

12

12

Sediment,

suspended, 

diameter, 

percent 

finer than

0.062 mm

68

65

82

86

92

89

68

67

75

75

84

83

58

51

Sediment, 

suspended 

(mg/L)

60

64

31

35

7

8

31

29

137

135

17

17

18

23
50 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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

[The terms "filtered" and "unfiltered recoverable" replace the former terms "dissolved" and "total recoverable," 

respectively. Abbreviations: ^ig/L, micrograms per liter; mg/L, milligrams per liter; mm, millimeter]

Constituent and reporting unit

Calcium, filtered, mg/L

Magnesium, filtered, mg/L

Arsenic, unfiltered recoverable, ^g/L

Arsenic, filtered, \ngfL

Cadmium, unfiltered recoverable, ^ig/L

Cadmium, filtered, ^g/L

Copper, unfiltered recoverable, |ig/L

Copper, filtered, u,g/L

Iron, unfiltered recoverable, u,g/L

Iron, filtered, ug/L

Lead, unfiltered recoverable, ng/L

Lead, filtered, [ig/L

Manganese, unfiltered recoverable, ng/L

Manganese, filtered, u.g/L

Zinc, unfiltered recoverable, u,g/L

Zinc, filtered, ng/L

Sediment, suspended, mg/L

Sediment, suspended, percent finer than 0.062 mm

Number of 

replicate pairs

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

Standard 

deviation, 

in listed 

units

0.53

.14

.38

.15

.01

.01

1.7

.13

19

1.3

.33

.02

5.9

1.6

1.6

.38

2.2

2.5

Relative 

standard 

deviation, 

in percent

1.2

1.4

2.8

1.6

3.5

13

4.6

1.4

2.2

2.0

4.3

7.5

4.2

2.4

2.9

3.3

5.0

3.3
TABLE 10 51

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

basin, Montana

[The terms "filtered" and "unflltered recoverable" replace the former terms "dissolved" and "total recoverable," respectively. 

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

Constituent and reporting unit

Calcium, filtered, mg/L

Magnesium, filtered, mg/L

Arsenic, unfiltered recoverable, (xg/L

Arsenic, filtered, ng/L

Cadmium, unfiltered recoverable, \igfL

Cadmium, filtered, ng/L

Copper, unfiltered recoverable, ng/L

Copper, filtered, \ig/L

Iron, unfiltered recoverable, ng/L

Iron, filtered, j-ig/L

Lead, unfiltered recoverable, ug/L

Lead, filtered, ug/L

Manganese, unflltered recoverable, jxg/L

Manganese, filtered, (xg/L

Zinc, unfiltered recoverable, [igfL

Zinc, filtered, ^ig/L

Number of 

replicate pairs

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

Standard 

deviation, 1 

in listed 

units

0.93

.17

.67

.16

.01

.00

.56

.08

5.1

1.6

.06

.02

.84

1.9

.42

.24

Relative 

standard 

deviation, 

in percent

2.1

1.6

4.3

1.1

4.8

5.0

2.8

1.5

1.1

5.8

2.2

11

1.4

9.4

1.3

1.7

Within limits of 

data-quality 

objective

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

'Statistics calculated using laboratory reporting level for censored values less than the detection capability of the instrument.
52 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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

[The terms "filtered" and "unfiltered recoverable" replace the former terms "dissolved" and "total recoverable," respectively. 

Abbreviation: jig/L, micrograms per liter]

Constituent and reporting unit

Arsenic, unfiltered recoverable, jxg/L

Arsenic, filtered, [ig/L

Cadmium, unfiltered recoverable, jig/L

Cadmium, filtered, ^ig/L

Copper, unfiltered recoverable, ng/L

Copper, filtered, ng/L

Iron, unfiltered recoverable, jig/L

Iron, filtered, |xg/L

Lead, unfiltered recoverable, [ig/L

Lead, filtered, jig/L

Manganese, unfiltered recoverable, \ig/L

Manganese, filtered, (xg/L

Zinc, unfiltered recoverable, jig/L

Zinc, filtered, ^ig/L

Number of 

samples

4

4

4

4

3

4

4

4

4

3

4

4

4

4

95-percent

confidence 

interval for spike 

recovery,

in percent

78.5-115

71.3-104

94.1-101

92.6-105

93.2-102

93.0-108

96.4-107

87.4-98.8

93.9-98.1

92.3-102

90.7-101

79.7-114

93.2-105

89.8-113

Mean spike 

recovery, 

in percent

96.6

87.9

97.5

98.6

97.6

100.4

101.6

93.1

96.0

97.2

95.8

96.6

99.1

101.4

Within limits of 

data-quality 

objective

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes
TABLE 12 53

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

upper Clark Fork basin, Montana

[The terms "filtered" and "unfiltered recoverable" replace the former terms "dissolved" and "total recoverable," respectively. 

Abbreviation: [xg/L, micrograms per liter]

Constituent and reporting unit

Arsenic, unfiltered recoverable, (xg/L

Arsenic, filtered, |xg/L

Cadmium, unfiltered recoverable, u,g/L

Cadmium, filtered, M-g/L

Copper, unfiltered recoverable, ng/L

Copper, filtered, |xg/L

Iron, unfiltered recoverable, fxg/L

Iron, filtered, \ig/L

Lead, unfiltered recoverable, ng/L

Lead, filtered, ng/L

Manganese, unfiltered recoverable, jxg/L

Manganese, filtered, (xg/L

Zinc, unfiltered recoverable, |xg/L

Zinc, filtered, |xg/L

Number of 

samples

4

4

4

4

4

4

4

4

4

4

4

4

4

4

95-percent

rnnfiripnpp lylfllllUUIIVsG

interval for 

spike

recovery.

in percent

100-117

80.2-109

94.4-104

91.4-110

89.7-93.5

88.9-103

100-113

91.6-102

93.7-99.9

90.2-102

78.8-109

86.2-112

87.5-98.5

93.6-103

Mean spike 

recovery, 

in percent

108.6

94.6

99.0

100.5

91.6

95.8

106.4

96.7

96.8

96.0

93.9

99.3

93.0

98.4

Within limits of 

data-quality 

objective

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes
54 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) and Statistical Summaries of Data for Streams 

in the Upper Clark Fork Basin, Montana

Table 13. Chemical analyses of field blanks for water samples

[The terms "filtered" and "unfiltered recoverable" replace the former terms "dissolved" and "total recoverable," respectively. Abbreviations: °C, 

degrees Celsius; E, estimated; jig/L, micrograms per liter; jiS/cm, microsiemens per centimeter at 25 °C; mg/L, milligrams per liter. Symbols: 

<, less than analytical detection limit]

Date

FEE 2003

28...

APR

03...

29...

MAY

27...

JUN

01...

16...

JUL

28...

AUG

25...

Time

1200

1500

1330

1200

1800

1100

1800

1930

pH, 

onsite 

(standard 

units)

5.6

5.5

5.6

5.6

5.7

5.6

5.8

5.7

Specific n . . ... . . Arsenic, ., , . Cadmium, j , Calcium, Magnesium, Arsenic, ,. u ' Cadmium, ,. u , conductance, .... ' .... . .... . unfiltered .... , unfiltered filtered filtered filtered , . filtered , . onsite , ,,\ i /i v / /i i recoverable , , recoverable (mo/L) imn/Li (ua/L) lun/Ll t o/ \ A"^/ 1-/ I'ny/ 1-/ ^f-^y/ 1-/ / n \ \^y/M / /i \

((j,o/cm) (ng/L) vfAg/L)

2 E0.01 <0.008 <0.3

3 .02 <.008 <3

2 .01 <.008 <.3

2 .02 <.008 <.3

2 .01 <.008 <.3

3 E.01 <.008 <.3

1 E.01 E.003 <.3

1 .01 <.008 <3

<2

<2

<2

<2

<2

<2

<2

<2

0.34

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<0.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

Date

FEE 2003

28...

APR

03...

29...

MAY

27...

JUN

01...

16...

JUL

28...

AUG

25...

Copper, 

filtered 

WL)

0.2

<.2

<.2

<.2

<2

<2

<.2

<.2

Copper, 

unfiltered 

recoverable

(u-g/L)

<0.6

<.6

<6

<.6

<.6

<.6

<.6

<6

. Iron, . , Lead, Manga- Iron, ,. u . Lead, ,. u , 

... . unfiltered ,. u . unfiltered nese, filtered . . filtered . . ,. u . 

, . recoverable , ,. . recoverable filtered

ng ^g M-g

<10 <20 <0.08 <0.06 <0.2

<10 <20 <.08 <.06 <.2

<10 <20 <.08 <.06 <.2

<8 <20 <.08 <.06 <.2

<8 <6 E.05 <.06 <.2

<8 <6 <.08 <.06 <.2

<8 <6 <.08 <.06 <.2

<8 <6 <.08 <.06 <.2

Manganese, 

unfiltered 

recoverable

(|xg/L)

<0.22

<.22

<.22

<.22

<.22

<.22

<.22

<.22

Zinc, 

filtered 

(^g/L)

2

4

4

4

2

<1

<1

<1

Zinc, 

unfiltered 

recoverable

(ng/D

<2

2

<2

El

<2

<2

<2

<2
Table 14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, September 2003

[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: u,g/g, micrograms per gram of dry sample weight]

Station number 

(fig.D

12323600

12323750

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek 

diversion, near Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, 

near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula 1

Number 

of com- - 

posite 

samples

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

Concentration, in ng/g

Arsenic

186

103

111

204

101

80

77

32

113

33

5

19

2

23

6

Cadmium

41.9

7.4

10.0

9.4

8.7

9.0

9.6

5.8

6.2

5.3

2.8

3.9

1.8

5.8

3.0

Copper

3,400

196

1,030

1,600

1,310

1,090

1,080

438

47

321

6

211

11

326

69

Iron

32,200

19,100

26,200

30,300

28,100

25,200

24,300

19,500

23,200

17,400

16,800

12,600

14,800

19,200

13,100

Lead

581

73

137

218

178

155

148

68

175

68

11

48

11

54

24

Manganese

5,220

14,400

12,600

9,670

6,310

8,370

3,980

2,180

5,720

3,090

490

1,410

605

1,420

1,420

Nickel

15.3

13.0

18.3

16.3

15.6

12.9

13.6

12.2

11.4

10.8

11.3

8.7

9.8

12.7

8.4

Silver

11.3

4.4

5.5

7.6

5.8

5.7

4.7

2.4

6.3

2.7

.8

1.7

.7

2.1

1.0

Zinc

7,630

726

1,130

1,560

1,380

1,230

1,260

669

626

761

23

663

39

716

239

'Samples collected about 30 miles downstream from streamflow-gaging station to conform to previous sampling location.
Table 15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, September 2003

[Bulk bed sediment collected in this study generally is material smaller than about 10 millimeters in diameter. Reported concentrations are the mean of all analyses for replicate aliquots of 

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

Station number 

(fig.D

12323600

12323750

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek diversion,

near Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula 1

Number 

of composi'e Arsenic 

samples

1 148

1 36

1 97

1 82

1 90

1 82

1 84

1 15

1 80

1 31

1 1

1 18

1 <.5

1 4

1 1.1

Concentration, in ^ig/g

Cadmium

21.7

3.4

4.7

5.2

10.5

5.6

8.3

3.2

3.6

5.1

.5

5.5

2.5

2.4

1.2

Copper

1,850

60

540

420

600

640

820

170

20

310

<.6

250

10

80

10

Iron

25,700

13,200

15,100

18,300

15,700

16,700

22,000

11,900

14,700

16,000

5,300

15,400

13,000

11,100

8,400

Lead

392

30

94

71

85

94

122

56

111

65

2

46

5

20

5

Manganese

2,900

1,990

3,130

3,720

4,170

3,070

3,560

930

2,690

3,280

60

2,620

330

570

220

Nickel

9.8

10.3

7.2

8.4

9.9

7.9

11.8

8.3

7.1

10.3

4.0

10.9

8.7

8.1

4.6

Silver

5.9

.9

1.7

2.0

2.5

2.3

3.5

1.0

4.3

2.6

.4

1.8

.8

.9

.3

Zinc

3,480

220

510

560

1,000

610

950

310

360

680

.3

590

20

290

40

c

"5 2L ^ ^i

i1 £

3- §. DO 5' 

B) ~ 

V> CD 5' 3

i 1

tt 5" 

too'

2L

a

0)

&

O

o

oaCD

i

3

e

CO

CD =

CD

3

«y

CD

ro

0)

=3

sf

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

2L

CO

i
TABLE 16 57

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

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

could not be determined because all analyses were less than the analytical detection limit]

Constituent

Arsenic

Cadmium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Arsenic

Cadmium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number of 

measurements

7

7

7

7

7

7

7

7

7

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 

N/g)

SRM sample 2709

17.7

.4

35

35,000

19

538

88

.4

106

SRM sample 2711

105

41.7

114

28,900

1,160

638

20.6

4.6

350

Mean SRM 

recovery 

(percent)

68.1

--

50.4

88.4

83.1

94.4

90.6

--

76.2

84.4

115.6

66.2

86.5

108.4

88.2

90.7

78.5

88.0

95-percent confidence 

interval for SRM 

recovery 

(percent)

67.8-68.4

--

48.8-52.3

87.5-89.4

79.2-87.0

93.4-95.4

89.6-91.6

-

72.2-80.0

80.7-88.1

110-121

64.0-68.3

83.4-89.6

104-112

85.1-91.4

86.8-94.6

75.9-79.6

84.3-91.7
Table 17. Trace-element analyses of procedural blanks for bed sediment

[Abbreviation: ng/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 (normal) hydrochloric acid used for reconstituting dried residue. Symbol: <, less than]

Station number

12323600

12323750

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek diversion, near 

Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula

Dilution

ratio . Arsenic

1:1 <0.003

1:1 <.003

1:1 <.003

1:1 <.003

1:1 <.003

1:1 <.003

1:1 <.003

1:1 <.003

1:1 <.003

1:1 <.003

1:1 <.003

1:1 <003

1:1 <003

1:1 <.003

1:1 <.003

Trace-element concentration, in |xg/mL

Cadmium

0.0001

<.0001

<.0001

<.0001

<0001

<.0001

<.0001

<0001

<.0001

<.0001

<.0001

<.0001

<.0001

<.0001

<.0001

Copper

<0.003

<.003

<.003

<.003

<003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

<.003

Iron

<0.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

Lead

<0.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

Manganese

<0.001

<001

<.001

<.001

<.001

<001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

Nickel

<0.001

<.001

<.001

<.001

<001

<.001

<.001

<001

<.001

<.001

<001

<.001

<.001

<.001

<.001

Silver

<0.001

<.001

<001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

<.001

Zinc

<0.002

<.002

<.002

<.002

<.002

<002

<.002

<.002

<.002

<.002

<002

<.002

<.002

<.002

<.002

Water-Quality, Bed-Sediment, Upper Basin, in theClark Fork

^ a» 

fg.

Is

= 2.

(B53' 

at

0

Oi

O

ioCD

1

3

c

(B

C/}

CD o

<D

oCD

CO

Oi

3

Q.

Statistical 1 

e 

3

0)

(A

2.

o

0)

S

f

CO

CD 

Oi

v>
TABLE 18 59

Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, September 2003

[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: 

Hg/g, micrograms per gram of dry sample weight; spp., species. Symbol: <, less than analytical detection limit]

Taxon

Number of 

composite 

samples

Concentration, in JAQ/Q

Arsenic

CadmiumChromiumCopper

Iron Lead

Manganese

Nickel Zinc

12323600 Silver Bow Creek at Opportunity

Hydropsyche cockerelli

Hydropsyche spp.

Hydropsyche cockerelli

Hydropsyche occidentalis

1

3

2

2

20.4

20.1

12323750

17.8

26.2

7.8

5.4

4.8

3.0

477

465

1,820

2,100

39.4

37.9

3,030

1,320

2.7

2.4

1,590

1,100

Silver Bow Creek at Warm Springs

.5

.7

4.1

6.2

27.2

35.6

1,080

1,740

2.4

4.2

2,270

3,450

1.5

2.4

159

194

12323800 Clark Fork near Galen

Hydropsyche cockerelli

Hydropsyche occidentalis

1

3

13.6

16.1

461415112450801

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche spp.

1

3

2

1

1.5

11.5

12.8

12.0

.7

.8

4.4

4.3

89.8

120

1,350

1,790

7.7

9.6

2,140

1,660

1.2

1.4

166

181

Clark Fork below Lost Creek, near Galen

.4

1.1

1.4

1.6

.4

2.7

2.8

1.2

67.1

98.4

115

103

209

1,030

1,270

1,050

.7

8.5

8.5

8.7

90

1,380

1,240

1,230

<.2

.9

1.0

1.0

208

173

188

163

4615591 12443301 Clark Fork near Racetrack

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche spp.

2

2

1

11.6

14.0

11.8

1.4

2.1

2.4

2.6

3.4

1.1

100

139

113

1,160

1,770

1,290

8.2

11.0

9.6

1,050

1,440

1,130

.9

1.3

1.3

171

218

181

461903112440701 Clark Fork at Derrmsev Creek diversion, near Racetrack

Hydropsyche cockerelli

Hydropsyche occidentalis

1

1

18.8

24.0

1.3

1.8

4.0

6.2

190

238

2,310

3,390

17.7

21.8

1,530

2,150

1.7

2.3

275

355

12324200 Clark Fork at Deer Lodge

Hydropsyche cockerelli

Hydropsyche occidentalis

1

2

10.1

11.8

.9

1.2

1.0

2.8

105

135

1,250

1,620

13.1

12.7

1,060

1,090

1.1

1.2

192

218

12324680 Clark Fork at Goldcreek

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

6

3

4

1

6.1

.9

5.9

5.8

.7

.5

.5

.5

2.0

.3

2.7

2.3

43.4

62.8

52.7

64.8

789

123

999

1,120

3.6

.5

5.2

5.6

729

107

963

809

.9

.2

1.0

1.1

156

272

146

169

12331500 Flint Creek near Drummond

Arctopsyche grandis

Hydropsyche cockerelli

3

2

8.1

17.0

.4

.7

5.8

8.5

18.6

21.3

1,700

4,070

8.6

19.9

2,690

2,940

1.4

3.2

234

218

12331800 Clark Fork near Drummond

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

3

2

2

2

3.3

.7

4.4

4.3

.5

.4

.5

.4

1.5

.3

2.4

2.4

27.0

59.3

43.7

45.0

529

128

989

1,170

3.3

.6

5.6

5.6

645

129

859

871

.6

<.2

1.0

1.0

147

261

155

179
60 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Taxon

Number of 

composite 

samples

Concentration, in ^ig/g

Arsenic

Cadmium

Chro- Copmium per

Iron Lead Manga- M . . . b Nickel 

nese

Zinc

12334510 Rock Creek near Clinton

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

4

1

1

1

2.0

1.1

2.4

2.2

.2

.1

.3

.4

<.2 8.3

<.2 21.3

.3 8.2

<2.0 5.1

464

103

825

973

.2

<2

.4

<2.1

165 .8

43 .3

266 .9

295 1.3

109

139

96.4

99.4

12334550 Clark Fork atTurah Bridae. near Bonner

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

4

2

3

1

1

1

3

2

2

2

3

2

5

1

4.7

.8

3.9

3.6

12340000

2.8

3.2

12340500

4.2

.9

6.4

6.2

12353000

2.5

.8

2.4

2.5

.4

.3

.3

.4

<.2 24.8

<.3 38.6

<.2 30.3

<.2 27.4

464

65

618

741

2.1

<.3

2.8

3.3

382 .7

76 <.3

566 .8

612 .9

130

172

128

157

Blackfoot River near Bonner

<.2

<.4

<.3 12.4

<.5 12.8

769

1,500

.5

1.3

476 1.2

577 1.4

138

142

Clark Fork above Missoula

.5

.3

.5

.5

3.2 48.1

.7 42.4

5.9 61.1

5.4 59.9

1,340

265

2,340

2,340

6.2

1.3

9.5

10.0

1,350 1.7

373 .3

1,800 2.2

1,950 2.3

207

240

234

254

Clark Fork below Missoula-

.2

.1

.2

.1

<.4 15.8

<.2 47.1

.6 19.9

<.6 13.5

535

82

678

728

1.4

.2

1.4

1.9

595 .8

102 <.2

793 .7

727 .8

124

212

101

133

Samples collected about 30 miles downstream from streamflow-gaging station to conform to previous sampling location.
TABLE 19 61

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

[Abbreviations: jxg/g, micrograms per gram of dry sample weight; (xg/mL, micrograms per milliliter; SRM, standard 

reference material]

Constituent

... , , Certified Number of . .. concentration measurements . . . (ng/9)Mean SRM 

recovery 

(percent)

95-percent confidence 

interval for SRM recovery 

(percent)

SRM sample TORT-2

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

12

12

l \2

12

12

2 12

12

12

12

21.6

26.7

.77

106

105

.35

13.6

2.5

180

101

88.8

74.3

92.5

94.9

48.4

88.3

80.4

93.3

98.8-104

85.2-92.4

19.1-129

90.4-94.7

90.2-100

17.2-79.7

83.7-92.8

73.5-87.4

89.4-97.2

'Chromium concentrations in six samples were less than the analytical detection limit (0.03 

Lead concentrations in seven samples were less than the analytical detection limit (0.01
62 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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

Station 

number

Station 

name

Dilution

ratio A Cad- Chro- n . . . Manga- ... . . -,. Arsenic . . Copper Iron Lead Nickel Zinc

mmm mmm nese

12323600

12323750

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

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 Galen 1 : 1

Clark Fork near Racetrack 1 : 1

Clark Fork at Dempsey Creek diversion, 1 : 1 

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

Rock Creek near Clinton 1 : 1

Clark Fork at Turah Bridge, near Bonner 1 : 1

Blackfoot River near Bonner 1 : 1

Clark Fork above Missoula 1 : 1

Clark Fork below Missoula 1 : 1

<0.01 <0.002

<.01 <.002

<.01 <.002

<.01 <.002

<.01 <.002

<.01 <.002

<.01 <.002

<.01 <.002

<.01 <.002

<01 <.002

<.01 <.002

<.01 <.002

<.01 <.002

<.01 <.002

<.01 <.002

<0.03 <0.01

<.03 <.01

<.03 <.01

<.03 <.01

<.03 <.01

<03 <.01

<.03 <.01

<.03 <.01

<.03 <.01

<.03 <.01

<.03 <.01

<.03 <.01

<.03 <.01

<03 <.01

<.03 <.01

<0.06 <0.01 <0.01 <0.01 <0.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01

<.06 <.01 <.01 <.01 <.01
TABLE 21 63

Table 21. Statistical summary of water-quality data forthe upper Clark Fork basin, Montana, March 1985 through September 2003

[The terms "filtered" and "unfiltered recoverable" replace the former terms "dissolved" and "total recoverable," respectively. Abbreviations: ft3/s, 

cubic feet per second; °C, degrees Celsius; E, estimated; (xg/L, micrograms per liter; nS/cm, microsiemens per centimeter at 25 °C; mg/L, milligrams 

per liter; mm, millimeter; ton/d, tons per day. Symbols: <, less than analytical detection limit 1 ; , indicates insufficient data greater than the 

analytical detection limit to compute statistic]

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

1 2323230- BLACKTAIL CREEK AT HARRISON AVENUE. AT BUTTE. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (^iS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCC^)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L) 

Arsenic, unfiltered recoverable (\igfL)

Arsenic, filtered (pig/L)

Cadmium, unfiltered recoverable (ng/L)

Cadmium, filtered (ng/L)

Copper, unfiltered recoverable (ng/L) 

Copper, filtered (\ig/L)

Iron, unfiltered recoverable (fig/L)

Iron, filtered (ng/L) 

Lead, unfiltered recoverable (jxg/L) 

Lead, filtered (^.g/L)

Manganese, unfiltered recoverable (|xg/L)

Manganese, filtered (ng/L)

Zinc, unfiltered recoverable (jig/L) 

Zinc, filtered (jig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

March 1993-August 1995, December 19%- August 2003

83

83

83

83

83

83

83 

83

83

83

83

83 

83

83

83 

83 

83

83

83

83 

83

83

83

83

156

412

17.5

8.4

150

41.8

11.0 

18

13

.11

.5

52 

10

4,220

478 

47 

1

240

144

130 

11

139

59

97

1.9

116

1.5

7.3

38

10.6

2.71

<2

1

<.04

<.l

1.5

E.8

140

15 

<.08

24

17

<10

2

.02

50

14

267

8.2

7.8

105

30

7.3

25

4

2<.l

2<.l

7 

24

700

163

22 

2.2

62

44

24

15

1.4

83

7.9

271

8.0

7.8

110

31

7.4 

4

3

<1

<1

6

3

550

157 

1

53

39

3 

3

7

.14

84
64 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

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

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (piS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3 )

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (|xg/L)

Arsenic, filtered ((J-g/L)

Cadmium, unfiltered recoverable (n-g/L)

Cadmium, filtered (ng/L)

Copper, unfiltered recoverable (n-g/L)

Copper, filtered (ng/L)

Iron, unfiltered recoverable (^g/L) 

Iron, filtered (ng/L)

Lead, unfiltered recoverable (ng/L) 

Lead, filtered (M-g/L)

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

Manganese, filtered (ng/L)

Zinc, unfiltered recoverable (|ig/L)

Zinc, filtered (fAg/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

March 1993- August 1995, December 1996-September 2003

83 134 13 30

83

83

83

83

83

83

83

83

83

83

83

83

83 

83

83 

83

83

83

83

83

82

82

82

691

20.0

8.1

180

51.6

13.0

45

13

6

6.2

550

303

7,400 

270

250 

2.4

1,600

1,700

2,200

2,200

405

70

98

226

1.0

7.2

66

19.0

4.51

4

4

.11

.09

13.5

4.5

90 

E10

.65 

<.5

26

21.4

45

34

2

.09

42

469

10.3

7.6

148

42

10

13

7

2.0

1.5

116

50

1,100 

286

18 

2.6

514

463

602

496

29

3.5

84

24

478

9.5

7.6

150

43

11

11

7

1.8

1.2

82

32

700

74

7 

.12

470

394

460

358

12

.92

86
TABLE 21 65

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

through September 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (jxS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (^g/L)

Arsenic, filtered (^ig/L) 

Cadmium, unfiltered recoverable (|xg/L)

Cadmium, filtered (ng/L)

Copper, unfiltered recoverable (^ig/L)

Copper, filtered (^g/L)

Iron, unfiltered recoverable (fig/L) 

Iron, filtered (M-g/L)

Lead, unfiltered recoverable (|ig/L) 

Lead, filtered (fig/L)

Manganese, unfiltered recoverable (^ig/L)

Manganese, filtered (fig/L)

Zinc, unfiltered recoverable (|u.g/L)

Zinc, filtered (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

March 1993- August 1995, December 1996-September 2003

86

85

85

85

85

85

85

85

85 

85

85

85

85

85 

85

85 

85

85

85

85

85

86

86

86

361

616

22.5

9.5

220

62.7

15.0

235

34 

49

41

3,900

450

24,100 

307

650 

5.1

10,000

9,300

15,000

13,000

801

781

95

13

202

0.0

7.2

60

18.5

3.42

11

1

.52

.1

54.3

19.4

260

3

5.38 

<5

117

68

97

27

5

.18

37

77

400

9.3

8.4

143

42

9.1

30

11 

22.6

1.5

258

55

1,770 

248

47 

2 .8

672

545

671

396

58

26

78

52

388

9.5

8.4

140

41

8.7

18

10 

1.8

.9

140

43

830 

26

16 

<1

490

421

460

220

18

3.0

82
66 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12323700-MILL CREEK AT OPPORTUNITY. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3 )

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable ((J-g/L)

Arsenic, filtered (u,g/L)

Cadmium, unfiltered recoverable (ng/L)

Cadmium, filtered (\igfL)

Copper, unfiltered recoverable (ng/L)

Copper, filtered (pig/L)

Iron, unfiltered recoverable (u,g/L)

Iron, filtered (jig/L)

Lead, unfiltered recoverable (^ig/L)

Lead, filtered (ng/L)

Manganese, unfiltered recoverable (n-g/L)

Manganese, filtered (jAg/L)

Zinc, unfiltered recoverable (u,g/L)

Zinc, filtered (fig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

March 2003-September 2003

261

207

18.5

8.2

85

23.5

6.57

50

37.0

.85

.10

38.8

6.0

1,960

60

12.7

.32

113

15.7

41

6

107

55

88

2.1

59

3.0

7.8

24

7.01

1.57

22

20.5

.06

.05

3.2

2.2

100

37

.17

.11

6

3.6

2

2

1

.01

49

63

139

9.5

8.0

58

16.1

4.25

36

29.8

.25

.07

12.2

4.2

539

47

3.21

.20

31

7.8

13

3

26

11

70

18

149

9.2

8.0

62

17.2

4.55

36

30.7

.12

.08

7.2

4.2

205

48

1.14

.20

13

6.7

8

3

6

.26

78
TABLE 21 67

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

through September 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12323720--WILLOW CREEK AT OPPORTUNITY. MONT.

Period of record for water quality data:

Streamflow, instantaneous (ft /s)

Specific conductance, onsite (uS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCC^)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (ug/L)

Arsenic, filtered (ug/L)

Cadmium, unfiltered recoverable (fig/L)

Cadmium, filtered (u,g/L)

Copper, unfiltered recoverable (ug/L)

Copper, filtered (u.g/L)

Iron, unfiltered recoverable (^ig/L)

Iron, filtered (u.g/L)

Lead, unfiltered recoverable (ug/L)

Lead, filtered (u,g/L)

Manganese, unfiltered recoverable (u.g/L)

Manganese, filtered (u,g/L)

Zinc, unfiltered recoverable (u.g/L)

Zinc, filtered (n-g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

March 2003-September 2003

46

333

17.0

8.3

150

42.6

9.89

104

101

.30

.08

36.9

14.1

840

87

8.41

.50

70

49.3

41

10

51

6.3

96

6.3

181

3.5

7.9

73

22.0

4.37

16

13.2

.04

E.03

4.4

2.4

80

8

.71

.06

14

10.6

4

2

2

.04

76

19

270

10.4

8.0

116

33.3

7.88

48

45.8

.11

.05

14.0

6.3

300

45

2.62

.26

38

25.7

15

6

14

1.2

88

14

284

11.5

8.0

120

34.4

8.54

40

37.8

.10

.05

11.2

5.0

235

48

2.05

.26

34

21.6

14

6

8

.28

90
68 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

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

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s) 92

Specific conductance, onsite (MS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (Mg/L)

Arsenic, filtered (Mg/L) 

Cadmium, unfiltered recoverable (Mg/L) 

Cadmium, filtered (Mg/L)

Copper, unfiltered recoverable (Mg/L)

Copper, filtered (Mg/L)

Iron, unfiltered recoverable (M-g/L) 

Iron, filtered (Mg/L) 

Lead, unfiltered recoverable (Mg/L)

Lead, filtered (Mg/L)

Manganese, unfiltered recoverable (Mg/L)

Manganese, filtered (Mg/L) 

Zinc, unfiltered recoverable (Mg/L) 

Zinc, filtered (Mg/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

90

91

90

90

90

90

90

90 

90 

90

90

90

90 

90 

90

90

90

90 

90 

90

92

92

91

March 1993-September2003

662 16

783

25.0

9.3

310

90.4

21.4

94

60 

.56

.3

96.8

40

3,000 

93

41.8

1.0

899

875 

180

73

229

279

97

249

.5

8.0

97

27.9

5.94

10

6.8

3.4

1.9

70 

<5

<.08

55

11.8

1

.11

43

148

460

11.2

8.8

190

55

13

26

22 

2<.12 

2 .08

20

10

376

2 17 

23

2 .1

194

126

242 

2 10

13

8.7

82

105

466

11.5

8.8

190

56

12

24

21

14

8

300

15

2

<.5

150

80 

30 

6

7

1.8

85
TABLE 21 69

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

through September 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum

12323770--WARM SPRINGS CREEK AT WARM SPRINGS,

Minimum

MONT.

Mean Median

Period of record for water quality data: March 1993-September 2003

Streamflow, instantaneous (ft /s)

Specific conductance, onsite ((xS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3 )

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable ((xg/L)

Arsenic, filtered (|xg/L)

Cadmium, unfiltered recoverable (ng/L)

Cadmium, filtered (ng/L)

Copper, unfiltered recoverable (|J,g/L)

Copper, filtered (|^g/L)

Iron, unfiltered recoverable ((xg/L)

Iron, filtered (M-g/L)

Lead, unfiltered recoverable (ng/L)

Lead, filtered (jAg/L)

Manganese, unfiltered recoverable (ng/L)

Manganese, filtered ((Ag/L)

Zinc, unfiltered recoverable (u.g/L)

Zinc, filtered ([ig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

66

65

66

65

65

65

65

65

65

65

65

65

65

65

65

65

65

65

65

65

65

66

66

66

420

795

20.0

8.7

420

130

22.0

27

14

.36

E.I

96.7

16

1,670

30

14

1.8

1,400

570

60

10

100

87

88

2.8

139

.5

7.4

40

10.5

3.29

3

2

<1

<.l

2.3

1

40

<5

<1

<.08

57

22.6

<10

<1

2

.05

55

101

297

9.3

8.3

143

44

8.3

8

5

2.08

2.04

21

4

326

2 11

22

2 .1

228

135

2 11

22

19

10

73

57

283

9.2

8.3

130

40

7.5

6

5

<1

<.l

10

3

120

9

.4

<.5

190

110

3

<20

8

1.2

74
70 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12323800-CLARK FORK NEAR GALEN. MONT. 

Period of record for water-quality data: July 1988-September 2003

Streamflow, instantaneous (ft /s)

Specific conductance, onsite (fAS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3 )

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (|Ag/L)

Arsenic, filtered (ng/L) 

Cadmium, unfiltered recoverable (n-g/L) 

Cadmium, filtered (^g/L)

Copper, unfiltered recoverable (ng/L)

Copper, filtered (\ig/L)

Iron, unfiltered recoverable (fxg/L) 

Iron, filtered (pig/L)

Lead, unfiltered recoverable (ng/L) 

Lead, filtered (M-g/L)

Manganese, unfiltered recoverable ((xg/L)

Manganese, filtered (jj,g/L) 

Zinc, unfiltered recoverable (ng/L) 

Zinc, filtered (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

133

121

132

120

119

119

119

119

119 

119 

119

118

119

119 

119

119 

119

119

119 

119 

119

133

133

132

1,050

720

22.5

9.0

370

110

22.0

78

53 

3 

1

240

50

9,200 

110

31.0

3

1,400

460 

360 

110

338

459

97

14

197

0.0

7.5

81

24.2

5.08

3

4

4.8

2.3

60

<3

<.08

47

25.2

2

.12

41

215

425

10.0

8.5

185

55

12

20

15

2.2 

2.07

32

10

548 

2 16

2.2

253

116

248 

2 12

20

23

78

129

435

10.0

8.5

190

57

12

17

13

19

8

290 

11

2

200

82 

30

7

9

2.8

78
TABLE 21 71

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

through September 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12323850-LOST CREEK NEAR GALEN. MONT. 

Period of record for water-quality data: March 2003-September 2003

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (fiS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3 )

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (ng/L)

Arsenic, filtered (ng/L)

Cadmium, unfiltered recoverable (|xg/L)

Cadmium, filtered (ng/L)

Copper, unfiltered recoverable (^ig/L)

Copper, filtered (ng/L)

Iron, unfiltered recoverable (^ig/L) 

Iron, filtered (|xg/L)

Lead, unfiltered recoverable (ng/L)

Lead, filtered (ng/L)

Manganese, unfiltered recoverable (ng/L)

Manganese, filtered (jig/L) 

Zinc, unfiltered recoverable (M-g/L)

Zinc, filtered (M-g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

8

8

8

8

8

8

8

8

8

8

8

8

8

8 

8

8

8

8

8 

8

8

8

8

8

59

861

26.5

8.7

420

117

32.3

43

41.8

.11

.05

22.5

6.7

280 

18

1.30

.33

33

23.6 

9

2

24

3.8

77

1.3

540

4.5

8.4

200

48.5

18.0

9

10.3

E.02

E.02

4.4

2.5

10 

<8

E.04

<.08

2

1.9

<2

<1

2

.01

18

20

633

15.6

8.6

296

83.2

21.7

18

17.2

.05

.03

8.6

3.5

105

27

.46

--

15

10.4

24

--

11

.89

53

14

626

16.2

8.6

290

82.0

20.6

15

14.0

.04

.03

6.3

3.1

70 

6

.31

<.08

13

8.6

3

<1

9

.28

55
72 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12324200- CLARK FORK AT DEER LODGE. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (^iS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCC^)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (ng/L)

Arsenic, filtered (ng/L) 

Cadmium, unfiltered recoverable (u,g/L) 

Cadmium, filtered (|xg/L)

Copper, unfiltered recoverable (ng/L)

Copper, filtered (u,g/L)

Iron, unfiltered recoverable (u,g/L) 

Iron, filtered (|xg/L) 

Lead, unfiltered recoverable (^ig/L) 

Lead, filtered (^g/L)

Manganese, unfiltered recoverable (|^g/L)

Manganese, filtered ((J-g/L)

Zinc, unfiltered recoverable (ng/L) 

Zinc, filtered (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

185

168

184

133

125

125

125

135

135 

135 

135

134

135

135 

135 

135 

135

135

135

135 

135

185

185

176

March 1985-September2003

1,920

642

23.0

8.9

270

81.0

18

215

39

5

2

1,500

120

29,000 

190 

200 

6

4,600

400

1,700 

230

2,250

8,690

99

23

234

0.0

7.4

95

28.2

5.9

8

6 

<.l 

<.l

8.2

3.2

30 

<3 

<1 

<.08

12

1

4 

<10

2

.29

40

296

485

9.8

8.3

204

60

13

25

14 

2.5 

2.09

94

12

1,770 

2 15 

2 12 

2 .4

Til

44

104 

2 14

79

175

71

225

506

10.0

8.3

210

63

14

18

13 

<1 

<1

41

9

660 

9 

5 

<1

160

33

53 

10

23

12

72
TABLE 21 73

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

through September 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON,

Period of record for water-quality data:

Streamflow, instantaneous (ft /s)

Specific conductance, onsite (^iS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3 )

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (p,g/L)

Arsenic, filtered (p.g/L)

Cadmium, unfiltered recoverable (p.g/L)

Cadmium, filtered (p-g/L)

Copper, unfiltered recoverable (p-g/L)

Copper, filtered (p,g/L)

Iron, unfiltered recoverable (p,g/L)

Iron, filtered (ng/L)

Lead, unfiltered recoverable (fig/L)

Lead, filtered (ng/L)

Manganese, unfiltered recoverable (p,g/L)

Manganese, filtered (p.g/L)

Zinc, unfiltered recoverable (p.g/L)

Zinc, filtered (p.g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

104

92

103

91

86

86

86

91

91

91

91

90

91

91

91

91

90

91

91

91

91

104

104

104

Minimum

MONT.

Mean Median

March 1985-September 2003

2,080

347

22

8.6

170

49.3

11.9

17

7

2

.2

45

7

25,000

120

25

6

1,100

45.2

140

24

1,410

7,920

97

15

120

0.0

7.0

51

14.0

3.30

4

3

<.04

<.04

<1

<1

20

<3

<1

<08

<10

1.0

<1

<1

1

.08

32

283

231

8.5

8.1

106

31

7.1

7

5

2.1

--

24

22

1,090

235

22

2 .4

267

9

2 12

23

49

134

75

178

222

9.0

8.1

100

30

7.0

6

5

<1

<.l

2

1

260

23

<5

<1

30

8

<40

<20

9

4.4

80
74 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12324680- CLARK FORK AT GOLDCREEK. MONT.

Period of record for water-quality data: March 1993-September 2003

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (n,S/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCC^)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (ng/L)

Arsenic, filtered (n<g/L) 

Cadmium, unfiltered recoverable (ng/L) 

Cadmium, filtered (ng/L)

Copper, unfiltered recoverable (^ig/L)

Copper, filtered (ng/L)

Iron, unfiltered recoverable (u,g/L) 

Iron, filtered (ng/L) 

Lead, unfiltered recoverable (ng/L)

Lead, filtered (n-g/L)

Manganese, unfiltered recoverable (ng/L)

Manganese, filtered (|xg/L)

Zinc, unfiltered recoverable (u,g/L) 

Zinc, filtered (u.g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

91

90

91

90

90

90

90

90

90 

90 

90

89

89

90 

90 

89

89

90

90

90 

90

91

91

91

3,920

510

21.5

8.8

230

68.0

15.0

75

20

2

.2

440

36

12,000 

100

73

.8

1,100

57.3

510 

26

752

7,960

94

87

206

0.0

7.9

86

25.9

5.15

7

5.8

5.2

2.1

30 

<3

<.08

10

4.0

2

2

.94

43

774

370

9.7

8.3

162

48

10

16

10

2.2 

2.05

46

7

999

220

27

2.1

140

20

54

27

58

261

75

529

386

10.0

8.3

170

50

11

13

10

29

6

530 

13

4

<.5

100

19

35 

4

24

37

78
TABLE 21 75

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

through September 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12331500-FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft /s)

Specific conductance, onsite (jj,S/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCC^)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (^ig/L)

Arsenic, filtered (ng/L) 

Cadmium, unfiltered recoverable (|xg/L)

Cadmium, filtered (n-g/L)

Copper, unfiltered recoverable (^ig/L) 

Copper, filtered (|ig/L)

Iron, unfiltered recoverable (ng/L) 

Iron, filtered (fAg/L)

Lead, unfiltered recoverable (^tg/L) 

Lead, filtered (^ig/L)

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

Manganese, filtered (|xg/L) 

Zinc, unfiltered recoverable (ng/L) 

Zinc, filtered (|J,g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

133

122

131

119

112

112

112

119

119 

119

119

118 

119

119 

119

119 

119

119

119 

119 

119

133

133

133

March 1985- September 2003

892

529

21.0

8.8

260

73.0

20

57

20

3

.1

32 

7

7,200 

240

87

7

1,600

139 

290

27

556

904

98

2.8

134

0.0

7.5

59

16.4

4.3

7

5 

<.04

<.04

1

60

<3

<l<.5

50

14

3

.02

28

179

307

9.1

8.3

144

39

11

17

9

2.2

-

6

22

872 

238

2.6

207

42

237 

25

50

44

80

119

304

9.5

8.3

140

38

12

13

9

<.l

4

2

450 

21

7

130

37 

20 

3

26

7.8

84
76 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003} 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 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12331800--CLARK FORK NEAR DRUMMOND. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (|j,S/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCC^)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (^ig/L)

Arsenic, filtered (ng/L) 

Cadmium, unfiltered recoverable (ng/L)

Cadmium, filtered (ng/L)

Copper, unfiltered recoverable (ng/L)

Copper, filtered (ng/L)

Iron, unfiltered recoverable (n-g/L) 

Iron, filtered (ng/L) 

Lead, unfiltered recoverable (^g/L) 

Lead, filtered (ng/L)

Manganese, unfiltered recoverable (n-g/L)

Manganese, filtered (ng/L)

Zinc, unfiltered recoverable (fAg/L) 

Zinc, filtered (|-ig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

91

90

91

90

90

90

90

90

90 

90

90

88

88

89 

90 

86 

86

90

90

90 

90

91

91

91

March 1993-September 2003

3,860

630

22.5

8.5

300

83

22

62

20

2

.2

360

21

8,800 

150 

56 

1.2

880

60.7

490 

21

530

4,720

92

149

189

.5

7.8

74

21

5.2

8

6.6

<.l

4.6

1

20 

<3

<.08

8

4.5

3 

<3

2

1.7

38

1,080

406

10.6

8.3

182

52

12

17

11

2.2

2<.l

50

7

1,150

220 

29

2 .2

164

18

73 

27

74

380

73

817

420

11.0

8.3

185

54

13

14

10

<.l

26

6

560 

9

4

105

15

40

5

30

66

74
TABLE 21 77

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

through September 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12334510-ROCK CREEK NEAR CLINTON, MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (|xS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (^ig/L)

Arsenic, filtered (^ig/L)

Cadmium, unfiltered recoverable (ng/L)

Cadmium, filtered (|xg/L)

Copper, unfiltered recoverable (jxg/L)

Copper, filtered (fig/L)

Iron, unfiltered recoverable (^g/L)

Iron, filtered (^ig/L)

Lead, unfiltered recoverable (n-g/L)

Lead, filtered (ng/L)

Manganese, unfiltered recoverable (jag/L)

Manganese, filtered (ng/L)

Zinc, unfiltered recoverable (ng/L)

Zinc, filtered ([ig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

103

94

103

93

85

85

85

91

91

91

91

89

90

91

91

89

89

91

91

91

91

103

103

103

March 1985-September 2003

5,060

160

18

8.8

90

23.0

8.00

5

1

3

1

41

6

2,100

163

19

5

90

8

60

15

223

3,050

95

113

53

0.0

6.9

22

5.92

1.86

<1

<1

<.04

<.04

<6

<1

20

5

<.06

<.08

<10

<1

<1

<1

1

.31

35

970

107

8.3

8.0

50

13

4.3

2.9

2.6

2.1

--

24

2 1

298

2 34

22

2 .4

2 15

22

26

2 2

21

142

70

548

102

8.5

8.0

50

13

4.3

<1

<1

<1

<.l

2

<1

130

28

<1

<1

7

2

<10

<3

5

9.8

71
78 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12334550- CLARK FORK ATTURAH BRIDGE. NEAR BONNER. MONT.

Period of record for water-quality data: March 1985-September 2003

Streamflow, instantaneous (ft /s)

Specific conductance, onsite (u.S/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (^g/L)

Arsenic, filtered (ng/L) 

Cadmium, unfiltered recoverable (|^g/L) 

Cadmium, filtered (ng/L)

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

Copper, filtered (ug/L)

Iron, unfiltered recoverable (ng/L) 

Iron, filtered (ng/L) 

Lead, unfiltered recoverable (u.g/L) 

Lead, filtered (p~g/L)

Manganese, unfiltered recoverable (u,g/L)

Manganese, filtered (u.g/L) 

Zinc, unfiltered recoverable (M,g/L) 

Zinc, filtered (u.g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

188

163

187

134

124

124

124

133

133 

133 

133

131

132

133 

133 

129 

129

133

133 

133 

132

188

188

177

9,560

483

22.0

8.8

210

59.0

14.0

110

17 

4 

.11

500

25

19,000 

190 

100

7

2,000

37.4 

1,100 

39

1,370

34,700

98

296

139

0.0

7.4

54

14.9

3.94

3

2.7 

<.l 

<.04

3

El.l

40 

<3 

<1 

<.08

10

1.0 

<10

<3

2

3.5

27

1,890

304

9.3

8.2

132

37

9.4

11

6

2.3 

2.04

41

5

1,210

226 

29

2.4

143

8 

271

27

63

704

73

1,140

318

9.5

8.3

130

38

9.4

7

5 

<1 

<1

19

4

480 

15 

4 

<1

71

7 

36

5

22

64

74
TABLE 21 79

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

through September 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12340000--BLACKFOOT RIVER NEAR BONNER. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite ((xS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3)

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (ng/L)

Arsenic, filtered (|xg/L)

Cadmium, unfiltered recoverable (ng/L)

Cadmium, filtered (ng/L)

Copper, unfiltered recoverable (fig/L)

Copper, filtered (jxg/L)

Iron, unfiltered recoverable (jig/L)

Iron, filtered (n-g/L)

Lead, unfiltered recoverable (fig/L)

Lead, filtered ([xg/L)

Manganese, unfiltered recoverable (|J-g/L)

Manganese, filtered (|o,g/L)

Zinc, unfiltered recoverable (n-g/L)

Zinc, filtered (^g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

134

111

134

94

87

87

87

94

94

94

94

91

92

94

94

90

90

94

94

94

94

134

134

132

March 1985-September2003

13,400

294

21.0

8.7

140

37

13

4

2

2

1

34

7

3,600

100

25

8

180

11

60

15

271

7,670

98

344

131

0.0

7.5

55

14

4.9

<1

<1

<.04

<.04

<1

<1

10

<3

<06

<.08

<10

<1

<1

<1

1

1.1

42

2,720

207

9.2

8.3

102

26

9.0

2 1

2 .9

2 .2

--

26

22

503

2 19

23

2.5

233

23

27

23

32

575

80

1,310

205

9.5

8.3

97

25

8.6

1

1

<1

<.l

3

1

230

12

<1

<1

20

2

<10

<3

9

31

82
80 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12340500-CLARK FORK ABOVE MISSOULA. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft /s)

Specific conductance, onsite (jj,S/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, filtered (mg/L as CaCO3 )

Calcium, filtered (mg/L)

Magnesium, filtered (mg/L)

Arsenic, unfiltered recoverable (n-g/L)

Arsenic, filtered (u,g/L)

Cadmium, unfiltered recoverable (ng/L)

Cadmium, filtered (pig/L)

Copper, unfiltered recoverable (\ng/L)

Copper, filtered (u,g/L)

Iron, unfiltered recoverable (|xg/L)

Iron, filtered (|-ig/L)

Lead, unfiltered recoverable (u.g/L)

Lead, filtered (u.g/L)

Manganese, unfiltered recoverable (n-g/L)

Manganese, filtered (u,g/L)

Zinc, unfiltered recoverable (ng/L)

Zinc, filtered (^g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

154

131

151

111

111

111

111

111

111

111

111

109

110

111

111

106

106

111

111

111

111

154

154

149

July 1986-September 2003

21,600

399

21.0

8.7

170

46

13.0

69

9

5

.2

400

12.6

13,000

200

78

1.2

1,100

230

1,100

16

824

21,900

99

720

142

0.0

7.9

61

14

5.28

1

1

<.l

<.04

2

.7

40

<3

<1

<.08

10

6.2

<10

<1

2

5.8

44

4,510

253

9.3

8.3

116

31

9.2

5

3

2.2

2.03

17

3

643

2 23

23

2.2

68

18

233

24

39

1,010

87

2,400

261

8.5

8.3

120

32

9.2

4

3

<1

<.l

8

2

250

16

2

<.6

40

14

13

2

12

81

90

'Differing less-than (<) values for an individual constituent are the result of changes in the analytical detection limit during the period of record. 

Value is estimated by using a log-probability regression to predict the values of data less than the laboratory reporting level (Helsel and Cohn, 1988).
TABLE 22 81

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

August 1986 through September 2003

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

gram dry weight. 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. Symbols: <, less than the analytical detection limit; --, indicates insufficient 

data to compute statistic]

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number

Constituent of Maximum Minimum Mean

samples

12323600--SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for fine-grained bed-sediment data: 1992-2003

1 - - 186

12 42.0 23.7 33.1

10 32.4 16.8 25.7

12 9,020 3,390 5,090

12 41,200 28,200 36,300

12 1,030 381 762

12 9,220 1,690 3,430

11 21.4 12.7 15.7

12 20.0 8.3 15.5

12 13,400 5,620 8,460

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.

Period of record for fine-grained bed-sediment data: 1992-2003

1 - -- 103

12 12.2 4.2 7.5

10 34.1 12.3 20.8

12 769 169 366

12 27,200 15,400 20,900

12 100 50 72

12 17,700 1,470 7,890

11 19.1 9.2 14.6

12 4.4 .3 'l.9

12 2,220 620 1,060

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

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

4 5.8 1.3 3.4

4 33.4 27.5 30.8

4 892 779 850

4 22,400 16,800 20,400

4 86 67 81

4 11,000 2,020 6,950

4 21.9 17.6 19.2

4 5.1 3.1 3.8

4 421 372 391

12323800-CLARK FORK NEAR GALEN. MONT.

Period of record for fine-grained bed-sediment data: 1987, 1991-2003

1 - -- ill

14 20.1 4.0 10.0

10 33.9 19.1 27.0

14 2,300 991 1,280

14 39,800 22,600 28,200

14 235 113 145

14 15,600 2,780 8,840

11 23.2 15.4 18.7

14 7.3 <3.2 '4.4

14 3,560 1,090 1,690

Median

-

32.4

26.2

4,740

37,500

815

2,680

15.5

15.8

7,820

7.1

21.2

279

20,600

70

7,690

14.6

'1.8

830

3.2

31.1

864

21,200

85

7,410

18.6

3.5

385

9.3

26.7

1,180

27,400

137

8,510

18.3

'4.5

1,300
82 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Constituent Number of 

samples Maximum Minimum Mean

10.5

34.5

2,050

32,800

218

9,670

19.9

7.8

1,680

6.5

22.3

1,350

26,300

167

3,540

13.4

4.2

1,120

204

8.2

29.5

1,580

30,600

187

5,550

17.1

6.5

1,420

Median

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

Period of record for fine-grained bed-sediment data: 1996-2003

8.3

31.8

1,520

31,100

186

5,380

17.1

6.7

1,470

461559112443301-CLARK FORK NEAR RACETRACK. MONT. 

Period of record for fine-grained bed-sediment data: 1996-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

8.7

33.3

1,610

31,700

186

6,310

18.4

6.1

1,550

5.0 

19.1 

933 

23,100 

128 

2,100 

10.5 

<3.3 

1,030

101

7.3 

26.7 

1,240 

27,300 

151 

3,460 

14.7 

'5.0 

1,250

7.8 

29.2 

1,280 

28,400 

148 

3,020 

16.0 

'5.4 

1,180

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

Period of record for fine-grained bed-sediment data: 1996-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

10.3

34.1

1,550

33,700

155

8,370

16.9

6.2

1,570

4.3

16.0

766

22,000

115

1,810

9.5

2.7

900

80

7.2

26.3

1,070

27,100

135

3,870

13.5

4.9

1,160

7.5

26.4

1,060

26,800

134

2,660

14.0

5.0

1,150

12324200-CLARK FORK AT DEER LODGE. MONT. 

Period of record for fine-grained bed-sediment data: 1986-87,1990-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

16

10

16

16

16

16

11

16

16

10.0

43.9

4,180

35,300

242

6,020

21.1

7.9

1,730

4.4

19.5

837

22,600

121

1,460

12.2

2.4

940

77

6.9

32.0

1,380

27,900

155

2,850

16.1

4.7

1,290

6.8

33.9

1,070

27,600

150

2,420

15.3

4.5

1,290
TABLE 22 83

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

August 1986 through September 2003 Continued

 ^ . Number of ., . ... . Constituent . Maximum Minimum samples Mean Median

12324590--LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

5 2.3 .2

3 54.4 22.1

5 85 38

5 30,700 16,100

5 53 36

5 2,700 905

3 21.9 13.6

5 .9 <.5

5 204 161

12324680--CLARK FORK AT GOLDCREEK. MONT.

l.l

43.1

56

24,200

40

1,420

17.7

'.6

176

.9

52.9

40

24,200

37

1,040

17.6

'.8

170

Period of record for fine-grained bed-sediment data: 1992-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

l

12 8.1 3.5

10 48.9 24.9

12 1,080 393

12 30,600 19,500

12 152 61

12 2,610 1,160

11 18.6 10.9

12 4.8 2.3

12 1,320 590

12331500--FLINT CREEK NEAR DRUMMOND. MONT.

32

5.4

33.7

726

24,200

101

1,840

15.2

3.3

1,020

-

5.7

32.6

757

24,400

106

1,810

15.9

3.2

1,100

Period of record for fine-grained bed-sediment data: 1986, 1989, 1992-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

14 7.0 <.2

10 29.2 20.4

14 73 47

14 28,100 19,800

14 240 126

14 5,720 2,370

11 14.9 10.4

13 7.8 5.0

14 777 503

12331800-CLARK FORK NEAR DRUMMOND. MONT.

113

'3.5

25.0

60

23,400

173

3,930

12.4

6.4

635

'3.2

25.2

61

23,300

171

4,040

11.7

6.4

646

Period of record for fine-grained bed-sediment data: 1986-87, 1991-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

15 7.7 2.6

10 35.4 17.0

15 747 321

15 27,000 16,500

15 135 68

15 3,090 1,150

11 16.8 10.8

15 4.7 <3.2

15 1,230 761

33

4.9

30.1

512

21,800

94

1,860

14.2

'3.0

1,020

4.8

32.1

499

23,200

94

1,740

15.0

'2.9

1,030
84 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

 . Number of Constituent . samples Maximum Minimum Mean Median

12334510--ROCK CREEK NEAR CLINTON. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1989, 1991-99, 2001-03

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

15

9

15

15

15

15

10

14

15

3.7

27.9

16

21,400

16

724

14.8

1.9

58

<.2

16.5

3

13,100

<3

126

9.5

<.3

23

5

'.9

22.2

12

17,600

'9

382

12.1

'.5

44

»<.8

21.3

13

17,600

ho

382

12.1

J <.5

47

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

Period of record for fine-grained bed-sediment data: 1986, 1991-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

14

10

14

14

14

14

11

14

14

-

7.3

34.7

635

24,400

115

2,270

19.1

3.9

1,160

-

3.1

15.3

211

12,600

47

671

8.7

<1.9

586

19

4.2

26.0

376

19,000

73

1,200

13.3

'2.1

874

3.9

28.4

338

17,400

68

1,110

12.0

'1.9

861

1234QOOO--BLACKFOOT RIVER NEAR BONNER. MONT.

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

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

12

8

12

12

12

12

9

12

12

2.0

25.8

27

20,200

20

683

14.3

1.0

73

<.2

15.1

11

12,400

<13

298

9.4

<.3

35

2

'.7

20.5

20

16,800

'12

531

11.9

'.5

58

2003

'<1.2

21.8

21

16,800

'12

538

12.5

'.3

61

12340500--CLARK FORK ABOVE MISSOULA. MONT.

Period of record for fine-grained bed-sediment data: 1997-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

7

6

7

7

7

7

7

7

7

-

5.8

30.6

543

24,300

78

1,420

15.8

2.9

1,090

-

1.5

19.0

166

18,100

37

480

11.8

.8

438

23

3.5

26.6

326

20,600

55

1,040

13.5

'2.0

703

-

3.7

29.3

282

20,400

54

1,160

13.3

'2.1

696
TABLE 22 85

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

August 1986 through September 2003 Continued

Constituent Number of ... . . Maximum samples Minimum Mean Median

12353000-- CLARK FORK BELOW MISSOULA. MONT.2

Period of record for fine-grained bed-sediment data: 1986, 1990-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

i

15

10

15

15

15

15

11

15

15

6.0

27.6

293

21,100

58

2,530

14.1

3.0

675

-

l.l

12.3

69

13,100

12

446

8.4

.4

239

6

2.4

21.9

148

18,000

36

1,320

12.0

'1.3

391

1.9

22.6

138

18,600

36

1,260

12.5

'1.3

380

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

uncensored and censored values were used in determining the mean and (or) median. When all data were less than the

analytical detection limit, the median was determined by ranking the censored values in order of magnitude. 

2 

Samples collected about 30 miles downstream from streamflow-gaging station to conform to previous sampling location.
86 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003

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

gram dry weight. 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. Symbols: <, less than the analytical detection limit; 

--, indicates insufficient data to compute statistic]

 ... . Number of Constituent . samples Maximum Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for bulk bed-sediment data: 1993-95, 1997-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

10

9

10

10

10

10

10

10

10

-

30.2

18.1

3,800

29,300

398

5,480

12.7

8.0

5,930

-

4.2

9.6

670

18,300

198

504

6.0

3.2

1,720

148

13.7

13.5

1,580

23,500

289

1,870

8.1

5.1

3,310

-

10.6

12.7

1,260

23,300

270

1,210

7.7

4.4

2,840

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

Period of record for bulk bed-sediment data: 1993, 1995-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

10

9

10

10

10

10

10

10

10

_.

3.4

4.8

111

13,200

33

2,100

10.3

1.3

303

..

<.9

5.2

9

6,100

<10

209

4.8

<3

93

36

'1.3

8.7

48

9,700

'15

1,000

6.4

'.7

160

'1.3

9.2

37

9,800

'12

857

5.5

'.8

134

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

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

4

4

4

4

4

4

4

4

4

1.5

12.0

238

12,700

38

4,240

8.5

1.3

275

12323800--CLARK FORK NEAR GALEN.

Period of record for bulk bed-sediment data:

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

11

10

11

11

11

11

11

11

11

._

8.2

23.7

902

31,300

158

9,490

15.2

5.2

1,280

<8

7.4

127

8,010

18

1,220

5.7

<.8

146

MONT.

1993-2003

_.

<.9

4.2

223

9,930

41

900

4.9

.7

417

! .6

10.2

193

10,200

29

2,640

7.2

'.9

183

97

! 4.0

15.5

500

19,900

82

3,450

8.8

'2.1

706

l <.9

10.7

204

10,000

29

2,540

7.4

'1.0

155

'4.0

15.4

542

19,500

79

1,900

8.8

'1.6

653
TABLE 23 87

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

August 1993 through September 2003 Continued

 iV , Number of Constituent . samples Maximum Minimum

461415112450801--CLARK FORK BELOW LOST CREEK. NEAR GALEN

Period of record for bulk bed-sediment data

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

i

8

7

8

8

8

8

8

8

8

..

5.2

17.5

763

21,000

104

3,720

8.4

2.8

787

: 1996-2003

__

<.9

6.8

238

12,300

41

1,260

4.2

.8

339

Mean

.MONT

82

'2.7

11.7

427

16,600

70

1,750

6.5

'1.7

527

Median

__

'2.8

12.0

411

16,700

71

1,420

6.8

'1.6

539

461 5591 12443301 --CLARK FORK NEAR RACETRACK. MONT.

Period of record for bulk bed-sediment data

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

8

7

8

8

8

8

8

8

8

__

10.5

19.7

757

25,900

101

4,170

9.9

3.3

997

: 1996-2003

..

<.9

10.1

361

15,700

59

759

5.5

1.4

472

90

'4.2

15.0

526

19,000

80

1,680

7.8

'2.4

678

__

'3.0

14.7

535

18,200

81

1,430

8.2

'2.6

679

461 9031 12440701 -CLARK FORK AT DEMPSEY CREEK DIVERSION. NEAR RACETRACK. MONT.

Period of record for bulk bed-sediment data:

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

8

7

8

8

8

8

8

8

8

-

9.2

21.1

1,000

25,400

115

4,930

12.8

4.4

1,240

1996-2003

1.5

13.0

244

16,400

47

825

5.5

<.8

368

82

4.3

17.2

553

21,500

81

2,030

8.5

'2.4

658

3.4

17.3

592

22,200

88

1,740

8.4

! 2.5

608

12324200- CLARK FORK AT DEER LODGE. MONT.

Period of record for bulk bed-sediment data

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

11

10

11

11

11

11

11

11

11

8.3

29.2

906

25,000

122

3,560

12.3

3.9

1,060

: 1993-2003

_

1.0

12.1

281

13,200

45

607

7.7

<.7

456

84

'3.6

19.1

525

19,800

81

1,430

10.2

'2.0

665

..

'2.4

19.6

440

20,200

82

1,050

10.2

'1.6

599
Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

_ .^ ^ Number of .. . ... . Constituent . Maximum Minimum samples Mean Median

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

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

3 <1.5 <1.2

3 33.2 14.7

3 20 12

3 21,000 15,600

3 18 12

3 420 308

3 15.2 8.6

3 <1.6 <.7

3 86 65

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for bulk bed-sediment data: 1993-2003

1

11 7.6 1.1

10 33.2 15.0

11 858 175

11 24,900 11,900

11 92 37

11 2,930 377

11 15.9 8.3

11 3.7 <.7

11 1,020 305

12331500--FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-2003

1

11 3.8 <.2

10 13.9 4.9

11 40 16

11 15,700 8,630

11 120 51

11 3,200 1,150

11 8.0 4.5

11 5.8 2.5

11 429 178

12331800--CLARK FORK NEAR DRUMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-2003

1

11 5.1 <1.6

10 29.5 6.9

11 605 114

11 21,800 12,100

11 78 31

11 3,280 409

11 14.2 7.7

11 3.5 .5

11 939 381

! .7

26.7

17

18,000

15

354

11.8

'.6

75

15

'3.3

22.1

419

18,400

62

1,230

11.3

'1.8

648

80

'1.9

9.8

24

13,000

80

2,220

6.0

4.3

285

31

'2.7

18.4

265

16,000

49

1,190

10.3

] 1.7

586

'.7

32.1

19

17,300

14

333

11.7

'.8

73

__

'3.2

21.3

282

18,300

56

930

10.5

'1.5

623

__

'1.7

10.9

23

13,400

80

2,250

5.9

4.3

284

_

'2.5

17.2

223

15,900

47

980

9.8

'<3.2

515
TABLE 23 89

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

August 1993 through September 2003 Continued

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

_ ^ . Number of .. . ... . Constituent . Maximum Minimum samples

12334510-ROCK CREEK NEAR CLINTON. MONT.

Period of record for bulk bed-sediment data: 1993-99, 2001-03

1

10 3.0 <.2

9 22.6 .6.4

10 10 .6

10 14,800 5,290

10 12 1

10 270 60

10 10.2 3.6

10 <1.6 .1

10 37 .3

Mean

i

'.8

10.5

'5

8,360

'5

150

5.7

'.4

17

Median

..

'.5

8.8

'5

7,340

'5

144

5.0

'.4

17

12334550--CLARK FORK ATTURAH BRIDGE. NEAR BONNER. MONT.

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Period of record for bulk bed-sediment data: 1993-2003

1

11 5.5 .4

10 23.8 6.9

11 336 75

11 19,100 9,270

11 67 21

11 2,620 234

11 14.0 6.4

11 2.9 <.3

11 769 271

12340000--BLACKFOOT RIVER NEAR BONNER. MONT.

18

'2.4

15.3

192

13,500

39

860

9.3

'1.3

482

..

'2.3

16.0

186

13,200

37

642

8.8

'1.2

501

Period of record for bulk bed-sediment data: 1993-94, 1999-2001, 2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

l

6 2.5 <.2

5 19.2 6.7

6 19 6

6 17,000 10,300

6 11 5

6 650 179

6 9.8 7.5

6 <1.9 <4

6 58 23

12340500- -CLARK FORK ABOVE MISSOULA. MONT.

Period of record for bulk bed-sediment data: 1997-2003

1

7 5.2 <.8

6 31.5 9.7

7 630 43

7 21,500 11,100

7 84 7

7 888 228

7 14.4 8.1

7 3.4 <.4

7 1,210 145

<.5

'.9

13.0

14

13,800

9

340

8.8

'.5

38

4

'1.9

17.0

165

15,300

30

572

10.1

h.2

408

'<1.5

12.5

15

13,800

9

316

9.0

'.6

35

_

'<!.!

16.1

84

16,000

20

570

9.2

'.9

295
90 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Constituent Number of 

samples Maximum Minimum Mean Median

12353000--CLARK FORK BELOW MISSOULA. MONT.2

Period of record for bulk bed-sediment data: 1993-2003

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

l

11

10

11

11

11

11

11

11

11

__

3.0

12.7

77

13,300

23

560

8.1

<1.9

183

..

<.2

4.4

10

5,830

5

150

3.5

<.3

39

1.1

h.o

7.7

38

8,910

'10

338

5.4

'.5

110

'<!.!

7.1

30

8,830

'8

364

4.9

'.5

101

1 Value determined by arbitrarily substituting one-half of the analytical detection limit for censored (<) values when both uncensored 

and censored values were used in determining the mean and (or) median. When all data were less than the analytical detection 

level, the median was determined by ranking the censored values in order of magnitude.

Samples collected about 30 miles downstream from streamflow-gaging station to conform to previous sampling location.
TABLE 24 91

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

September 2003

[Concentrations are in micrograms per gram dry weight. 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, Hydropsyche species 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 collected during 1986-98 were depurated prior to analysis; 

depuration was discontinued in 1999. Abbreviation: spp., species. Symbols: <, less than analytical detection limit; , indicates either 

too few samples (less than three) or insufficient data to compute statistic, or element not analyzed]

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

12323600- 12323600- -SILVER -SILVER BOW BOW CREEK CREEK AT AT OPPORTUNITY. OPPORTUNITY. MONT. MONT.

Period of record for biological data: 1992, 1994-95, 1997-2003

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

5

5

5

5

5

5

5

5

1

7

7

7

7

7

7

7

7

3

8

8

8

8

8

8

8

8

6

6

6

6

6

6

6

6

Brachycentrusspp.

12.5

5.9

846

1,190

21.5

817

2.1

995

Hydropsyche cockerelli

9.7

8.0

1,090

2,660

47.2

3,030

3.6

1,590

Hydropsyche spp.

23.1

10.6

4.7

930

2,290

50.8

1,340

2.5

1,290

Hydropsyche tana

9.2

11.5

456

1,520

21.0

969

1.8

1,070

5.8

.7

235

335

7.4

231

<.l

629

4.1

1.0

269

689

19.0

180

.7

749

18.4

5.0

.6

352

1,270

34.7

712

1.6

1,070

4.8

.9

10.5

857

15.6

307

.7

760

10.1

2.1

587

617

13.7

515

'1.3

803

20.4

6.0

3.6

485

1,300

26.9

928

2.1

1,010

20.1

7.5

2.2

655

1,870

39.5

1,080

2.3

1,120

6.8

4.5

236

1,100

18.6

634

1.4

961

11.6

.9

592

469

13.8

503

'1.6

815

5.2

3.1

439

1,000

21.0

591

2.1

871

18.9

7.1

2.2

652

1,990

38.2

1,060

2.4

1,100

6.9

1.8

298

1,050

18.3

675

1.6

1,020
92 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

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

Period of record for biological data: 1992-2003

Hydropsyche cockerelli

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

2

28

28

28

28

28

28

28

28

18.2

2.1

4.3

97.0

1,240

5.7

2,520

1.8

276

17.4

.2

.4

22.4

351

.3

491

.3

115

17.8

.7

1.0

41.0

734

3.0

1,200

.9

178

.6

.8

38.1

744

2.8

914

.8

168

Hydropsyche occidentalis

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

2

17

17

17

17

17

17

17

17

4

4

4

4

4

4

4

4

26.8

1.6

6.8

48.9

2,960

8.2

3,540 1

2.7

211

Hydropsyche spp.

2.3

1.4

47.6

773

5.1

1,100

1.9

285

25.6

.2

.3

11.0

372

<1.7

,200

.7

141

.4

.5

34.9

561

1.9

443

<.4

141

26.2

.6

1.6

32.9

1,150

! 3.9

2,400

1.5

180

1.1

.8

40.9

680

2.9

725

'.8

195

.4

1.0

31.2

980

! 3.6

2,160

1.5

181

.9

1.2

40.6

693

4.7

678

1 .5

111

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

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

4

4

4

4

4

4

4

4

Arctopsyche grandis

3.0

2.9

102

1,040

5.6

3,560 1

2.3

222

1.9

.8

78.3

684

3.0

,340

1.8

181

2.4

1.7

93.7

839

'4.3

2,250

'2.1

196

2.2

1.6

97.2

815

4.3

2,040

2.2

190
TABLE 24 93

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

September 2003 Continued

Number of 

Constituent composite Maximum Minimum 

samples

Mean Median

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

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

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.

2 1.1 .6

2 1.6 1.4

2 95.9 94.8

2 1,220 1,150

2 5.9 5.2

2 3,390 956

2 2.0 1.8

2 129 125

12323800-- CLARK FORK NEAR GALEN. MONT.

Period of record for biological data: 1987, 1991-2003

Hydropsyche cockerelli

1

26 2.7 .7

26 4.4 .8

26 181 48.7

26 2,460 816

26 11.7 1.2

26 3,620 1,070

26 3.1 .9

26 299 136

Hydro psyche morosa group

5 3.2 2.4

5 4.6 1.8

5 185 156

5 1,890 1,360

5 12.4 7.1

5 3,960 2,360

5 3.6 1.9

5 349 292

Hydropsyche occidentalis

3 16.5 15.9

35 1.7 .6

35 6.6 .4

35 121 49.2

35 1,920 642

35 13.5 1.6

35 6,170 1,220

35 3.5 .8

35 286 168

.8

3.2

182

2,010

7.4

2,440

3.2

169

.9

1.5

95.3

1,190

5.6

2,170

1.9

127

13.6

1.5

1.8

98.0

1,380

7.5

2,240

1.6

210

2.5

2.6

173

1,510

8.5

3,500

2.3

309

16.1

1.1

2.0

82.0

1,260

7.0

2,560

1.6

199

--

--

--

--

--

-

--

-

--

1.5

1.6

95.0

1,340

7.6

2,250

1.4

208

2.4

2.2

175

1,430

7.9

3,860

2.1

303

16.1

1.0

1.5

80.8

1,200

6.5

2,240

1.5

191
94 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

12323800-CLARK 12323800-CLARK FORK FORK NEAR NEAR GALEN. GALEN. MONT. MONT. Continued Continued

Period of record for biological data: 1987, 1991-2003

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Hydropsyche tana

1

1

1

1

1

1 

1

1

Hydropsyche spp.

4 3.5 2.6

0

4 154 135 

4 1,540 1,190

4 13.5 10.5

0 

0

4 329 279

1.5

1.4

92.9 

1,340

9.0

2,160

2.1

206

3.0

-

148 

1,400

12.2

308

--

3.0

-

152 

1,450

12.4

313

461 41 51 12450801 -CLARK FORK BELOW LOST CREEK. NEAR GALEN. MONT.

Arsenic

Cadmium

Chromium

Copper 

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper 

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper 

Iron

Lead

Period of record for biological data: 1996-2003

Claassenia sabulosa

1

2 .4 .3

2 1.9 .4

2 70.1 67.1 

2 209 189

2 1.2 .7

2 238 90.4 

2 1.9 <.2

2 245 208

Hydropsyche cockerelli

3 11.8 11.2

14 2.8 1.1

14 2.7 .8

14 147 48.8 

14 2,570 691

14 15.2 4.5

14 3,160 1,230 

14 1.9 .9

14 321 151

Hydropsyche occidentalis

2 12.9 12.7

16 1.8 .9

16 3.3 1.3

16 157 52.1 

16 1,920 963

16 12.4 6.6

1.5

.4

1.2

68.6 

199

1.0

164 

'1.0

226

11.5

1.8

2.0

104 

1,330

10.3

1,890

1.3

214

12.8

1.3

2.0

104 

1,380

9.6

--

11.6

1.9

2.2

97.0 

1,180

9.8

1,700 

1.1

226

1.5

2.0

98.2 

1,270

9.8
TABLE 24 95

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

September 2003 Continued

Manganese

Nickel

Zinc

Arsenic

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: 1996-2003

Hydropsyche occidentalis Continued

16 3,440 1,220

16 1.7 .9

16 283 174

Hydropsyche spp.

1

5 1.8 1.2

5 2.4 .9

5 122 45.1

5 1,410 533

5 20.5 4.1

5 1,980 799

5 2.8 1.0

5 225 143

Mean

MONT. Continued

2,150

1.3

224

12.0

1.5

1.5

91.8

1,110

10.0

1,440

1.6

179

Median

1,850

1.3

226

1.4

1.5

103

1,200

8.7

1,230

1.4

179

461559112443301--CLARK FORK NEAR RACETRACK. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-2003

Claassenia sabulosa

1

1

1

1

1

1

1

1

Hydropsyche cockerelli

2 11.7 11.5

13 1.9 1.0

13 2.7 .6

13 109 50.0

13 1,370 657

13 10.5 3.7

13 2,010 646

13 1.4 .7

13 199 139

Hydropsyche occidentalis

2 14.3 13.7

15 2.2 .7

15 3.7 1.1

15 160 59.5

15 1,880 1,030

15 11.7 4.3

15 3,770 1,090

15 1.9 1.1

15 255 181

.4

.3

40.3

113

.8

172

.2

213

11.6

1.4

1.6

78.2

955

6.7

1,390

1.0

172

14.0

1.4

2.1

107

1,510

9.6

2,070

1.3

225

-

-

-

-

--

--

--

-

1.4

1.4

74.1

981

6.4

1,530

1.0

171

1.4

2.0

107

1,520

10.1

2,050

1.3

220
96 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Number of

Constituent composite Maximum Minimum

samples

Mean Median

461 5591 12443301 -CLARK FORK NEAR RACETRACK. MONT. Continued

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-2003

Hydropsyche spy.

]

3 2.4 1 .0

3 1.7 .7

3 113 82.9

3 1,290 1,140

3 9.6 5.7

3 1,600 910

3 1.4 1.1

3 208 151

11.9

1.6

1.2

93.7

1,210 1

7.5

1,210 1

1.3

180

1.5

1.1

85.2

,200

7.4

,130

1.3

181

461 9031 12440701 --CLARK FORK AT DEMPSEY CREEK DIVERSION. NEAR RACETRACK. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-2003

Arctopsyche grandis

1

1

1

1

1

1

1

1

Hydropsyche cockerelli

1

10 1.6 .7

10 4.0 .4

10 190 60.7

10 2,310 552

10 17.7 3.5

10 1,530 487

10 1.9 .5

10 275 162

Hydropsyche occidentalis

1

18 1.8 .7

18 6.2 .8

18 238 74.9

18 3,390 940

18 21.8 6.1

18 3,990 826

18 2.4 1.2

18 355 222

1.7

<2.4

30.8

340

<14.5

510

1.0

87

18.8

1.2

1.3

91.3

973

7.1

1,010 1

1.0

187

24.0

1.2

2.1

103

1,520 1

11.6

2,420 2

1.5

252

-

--

--

--

1.3

1.0

76.7

841

5.9

,140

.8

179

1.1

1.8

88.3

,500

11.4

,280

1.4

236
TABLE 24 97

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

September 2003 Continued

Constituent

Number of 

composite Maximum Minimum 

samples

Mean Median

461 9031 12440701 -CLARK FORK AT DEMPSEY CREEK DIVERSION. NEAR RACETRACK. MONT. Continued

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Period of record for biological data: 1996-2003

Hydropsyche spp.

2 1.7 1.6

2 2.1 1.4

2 140 104

2 1,610 1,070

2 13.2 10.5

2 1,150 638

2 1.6 1.6

2 212 191

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for biological data: 1986-87, 1990-2003

Arctopsyche grandis

2 2.4 <4.2

2 1.0 <1.3

2 69.1 34.9

2 676 537

2 <7.8 3.8

2 727 380

2 <1.7 <1.3

2 178 140

Hydropsyche cockerelli

1

24 2.3 .6

24 3.2 .4

24 136 54.7

24 3,340 490

24 18.2 4.3

24 1,490 396

24 2.4 .3

24 391 132

Hydropsyche occidentalis

2 12.4 11.3

39 2.7 .8

39 3.6 .6

39 162 49.4

39 2,060 557

39 18.6 3.5

39 2,840 649

39 12.9 1.0

39 329 166

Hydropsyche spp.

3 2.0 1.2

0

3 222 103

3 2,220 1,110

3 15.0 5.6

0

1.6

1.8

122

1,340

11.8

892

1.6

202

! 2.2

'.8

52.0

606

J 3.8

554

'--

159

10.1

1.4

1.6

94.5

1,140

9.7

817

1.2

186

11.8

1.3

1.9

113

1,420

11.0

1,670

1.8

237

1.6

145

1,520

8.8

--

--

-

-

-

--

_

-

-

--

--

1.3

1.7

98.0

1,050

8.9

710

1.0

188

1.3

1.9

110

1,430

10.8

1,710

1.4

231

1.6

Ill

1,240

5.7

--
98 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003} 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 2003 Continued

Constituent

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of

composite Maximum Minimum Mean

samples

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

Period of record for biological data: 1986-87, 1990-2003

Hydropsyche spp. Continued

o

3 203 185 195

12324590--LITTLE BLACK FOOT RIVER NEAR GARRISON. MONT.

Period of record for biological data: 1987, 1994, 1998, 2001

Arctopsyche grandis

15 .7 .2 .4

15 1.6 .6 .9

15 14.2 9.0 12.2

15 677 177 384

15 1.3 .5 .8

15 1,140 318 678

15 1.4 .4 .7

15 214 113 165

Claassenia sabulosa

1 .5 .1 .2

7 .9 .3 .6

7 36.1 20.0 29.4

7 319 98 175

7 <.8 <.l '.4

7 90.5 46.7 63.8

7 .7 .4 .5

7 233 172 203

Hydropsyche cockerelli

1 -- - .6

1 - - 1.6

1 - -- 28.4

1 - - 478

1 - - 3.6

1 -- -- 399

1 -- - 1.2

1 -- -- 123

Hydropsyche occidentalis

2 <.7 .3 1 .3

2 2.3 1.3 1.8

2 15.2 15.1 15.2

2 1,340 426 883

2 2.3 <3.7 "2.1

2 554 434 494

2 1.1 .8 1.0

2 137 110 124

Median

197

.4

.8

13.0

313

.8

551

.6

162

.2

.7

30.3

156

'.3

61.6

.5

202

--

_

._

-.

_
TABLE 24 99

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

September 2003 Continued

Constituent

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of 

composite Maximum Minimum 

samples

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for biological data: 1992-2003

Arctopsyche grandis

6 6.4 5.8

35 6.6 .6

35 3.3 .4

35 129 21.4

35 2,360 339

35 10.9 2.0

35 1,580 592

35 1.8 .2

35 326 149

Claassenia sabulosa

3 1.0 .7

23 3.5 .3

23 1.6 .2

23 81.7 33.0

23 567 63.0

23 1.8 .4

23 279 50.6

23 .7 .1

23 351 166

Hydropsyche cockerelli

4 6.1 5.7

23 2.6 .5

23 4.7 .5

23 188 17.1

23 3,250 522

23 16.2 2.4

23 1,670 538

23 2.3 .3

23 249 106

Hydropsyche morosa group

4 1.7 1.1

4 1.4 1.3

4 72.9 43.8

4 1,320 612

4 6.9 2.4

4 1,030 538

4 1.4 .9

4 190 137

Hydropsyche occidentalis

1

16 1.7 .5

16 3.9 .4

16 156 26.4

16 2,720 466

16 15.7 2.9

16 2,210 530

16 2.5 .8

16 277 97

Mean

6.1

2.2

1.4

48.0

769

4.0

851

.8

204

.9

1.2

.6

56.7

192

1.0

123

.3

263

5.9

1.4

2.2

73.5

1,220

7.2

862

1.2

183

1.4

1.4

60.5

1,050

4.6

804

1.2

167

5.8

1.2

1.6

64.4

1,140

7.2

1,140

1.2

193

Median

6.1

2.0

1.1

40.8

624

3.6

803

.7

186

.9

.8

.5

56.3

171

1.0

106

.3

261

6.0

1.3

2.0

58.6

1,010

5.5

900

1.2

186

1.4

1.4

62.7

1,130

4.6

822

1.2

170

1.3

1.7

59.8

1,070

6.0

1,020

1.1

190
100 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Constituent

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of 

composite Maximum Minimum 

samples

12331500--FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for biological data: 1986, 1992-2003

Arctopsyche grandis

3 9.0 7.4

42 .8 .1

42 7.1 .3

42 22.2 8.9

42 2,460 412

42 17.5 3.7

42 3,160 424

42 2.7 .6

42 275 93

Hydropsyche cockerelli

2 17.1 16.8

13 .9 .1

13 9.1 .9

13 28.3 9.5

13 4,400 996

13 28.4 3.1

13 3,020 401

13 4.0 .9

13 224 85

Hydropsyche occidentalis

7 1.1 .2

7 17.6 .7

7 27.3 15.1

7 2,990 912

7 29.8 5.8

7 4,790 1,400

7 6.9 .8

7 243 128

Hvdropsyche spp.

1

1

1

1

1

1

1

1

Hvdropsvche tana

2 <1.2 <.l

2 10.3 .6

2 16.0 5.4

2 1,320 729

2 15.3 5.0

2 1,400 1,180

2 3.1 .5

2 139 107

Mean

8.1

.4

2.1

15.2

1,360

8.9

1,570

1.4

199

17.0

.5

2.9

18.2

2,440

15.5

1,590

2.2

177

.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

1__

5.4

10.7

1,020

10.2

1,290

1.8

123

Median

7.8

.4

1.7

15.3

1,360

8.2

1,400

1.3

195

-.

.4

2.0

18.1

2,180

16.3

1,230

2.3

183

.6

2.1

18.6

1,870

24.0

1,780

2.4

188

_

_

_

_

-

..

_

..

..
TABLE 24 101

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

September 2003 Continued

Constituent

Arsenic

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper 

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel

Zinc

Number of 

composite Maximum Minimum 

samples

12331800--CLARK FORK NEAR DRUMMOND. MONT.

Period of record for biological data: 1986, 1991-2003

Arctopsyche grandis

3 3.6 3.2

35 3.8 .5

35 2.5 .2

35 89.2 16.9 

35 1,660 240

35 11.8 2.1

35 2,010 462 

35 1.9 .2

35 308 140

Claassenia sabulosa

2 .1 .7

38 2.8 .2

38 3.3 .1

38 165 18.0

38 387 45.4

38 2.9 .2

38 410 33.1 

38 1.1 .1

38 567 103

Hydropsyche cockerelli

2 4.5 4.4

31 2.3 .4

31 3.5 .4

31 156 30.0 

31 2,500 506

31 15.0 5.1

31 1,680 549 

31 2.0 .5

31 248 134

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

Hydropsyche occidentalis

2 4.3 4.3

18 2.0 .4

18 8.1 .4

18 118 13.3 

18 2,060 424

18 14.0 2.9

18 2,920 619 

18 2.4 .5

18 293 157

Mean

3.3

1.4

1.0

33.8 

604

4.6

840

.7

190

.7

1.1

.7

64.9 

159

.9

157 

.3

273

4.4

1.2

1.6

59.9 

1,180

8.6

946 

1.1

192

1.2

2.3

55.2 

1,570

8.9

1,610

1.5

239

4.3

1.1

2.4

54.6 

1,270

9.0

1,480 

1.4

221

Median

3.3

1.3

1.0

28.2 

547

4.1

733 

.6

189

1.1

.5

55.9 

135

.8

135

.2

253

.9

1.6

50.7 

984

7.7

901 

1.1

184

1.2

2.2

55.8 

1,600

9.0

1,620 

1.5

240

1.1

2.3

54.1 

1,190

8.7

1,210 

1.4

222
102 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Constituent

Number of 

composite Maximum 

samples

1 2331 800-- CLARK FORK NEAR DRUMMOND.

Minimum Mean Median

MONT. Continued

Period of record for biological data: 1986, 1991-2003

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Hydropsyche spp.

1

0

1

1

1

0

0

1

--

-

-

--

2.6

85.0

940

9.1

260

-

-

--

--

12334510-ROCK CREEK NEAR CLINTON. MONT.

Period of record for biological data: 1987, 1991-99, 2001-03

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arctopsyche grandis

4 2.2

42 .4

42 2.9

42 15.7

42 1,090

42 1.1

42 454

42 1.8

42 189

Claassenia sabulosa

1

20 .3

20 1.8

20 40.7

20 129

20 1.0

20 76.3

20 .9

20 264

Hydropsyche cockerelli

1

4 .3

4 1.0

4 13.1

4 825

4 <1.1

4 266

4 1.0

4 99

1.9

.06

.5

4.7

191

.05

113

.2

84

_

.05

.1

18.1

49.8

.1

15.7

.1

139

<.2

.3

6.0

485

.4

192

.4

82

2.0

.2

1.2

8.6

582

'.4

250

.9

127

1.1

.2

.7

28.4

93.2

.4

35.0

.4

195

2.4

'.2

.8

8.5

604

'.5

231

.6

91

2.0

.2

1.0

8.5

506

'.4

227

.9

130

_

.2

.6

27.9

102

.3

33.6

.3

191

__

<.2

.9

7.4

553

<1.1

233

.6

91

Hydropsyche occidentalis

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

1

5 .4

5 2.4

5 17.6

5 973

5 6.0

<.3

.9

5.1

520

1.2

2.2

'.2

1.6

10.6

709

3.0

..

.14

1.6

10.2

652

1.8
TABLE 24 103

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

September 2003 Continued

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of

Constituent composite Maximum Minimum Mean

samples

1 233451 0-- ROCK CREEK NEAR CLINTON. MONT. Continued

Period of record for biological data: 1987, 1991-99, 2001-03

Hydropsyche occidentalis Continued

5 295 169 242

5 1.7 .6 1.2

5 144 99 116

Hydropsyche spp.

3 .3 <5 1 .2

3 2.1 1.1 1.6

3 16.2 11.6 14.3

3 1,140 837 1,000

3 <3.1 <1.8 l3 462 299 399

3 1.3 .8 1.1

3 135 117 126

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

Period of record for biological data: 1986, 1991-2003

Arctopsyche grandis

4 5.0 4.5 4.7

46 2.7 .3 1.2

46 4.1 .6 1.7

46 125 20.1 38.8

46 2,870 372 979

46 13.2 1.6 4.5

46 893 324 615

46 2.7 .4 1.1

46 276 111 196

Claassenia sabulosa

2 .8 .8 .8

28 2.5 .2 1.0

28 2.0 .2 .7

28 79.2 37.5 55.7

28 181 58.6 102

28 1.6 .2 .6

28 139 37.2 76.2

28 .6 .1 .2

28 283 144 218

Hydropsyche cockerelli

3 4.1 3.7 3.9

31 1.8 .3 .8

31 8.0 .16 1.9

31 118 26.4 47.7

31 2,530 566 1,210

31 12.1 2.2 5.2

31 788 426 596

31 2.6 .6 1.2

31 228 119 182

Median

262

1.4

117

.2

1.7

15.0

1,030

<2.9

437

1.1

126

.9

1.5

30.4

827

3.8

626

.9

196

.8

.6

52.5

101

.6

68.5

.2

218

3.9

.7

1.6

42.5

1,090

5.0

575

1.2

180
104 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

12334550-CLARK 12334550-CLARK FORK FORK ATTURAH ATTURAH BRIDGE. BRIDGE. NEAR NEAR BONNER. BONNER. MONT. MONT. Continued Continued

Period of record for biological data: 1986, 1991-2003

Hydropsy 'che 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

-

--

-

Hydropsyche occidentalis

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

1

21

21

21

21

21

21

21

21

1

1

1

1

1

1

1

1

1.8

3.2

102

2,310

14.2

1,600

3.2

416

Hydropsyche spp.

--

--

-

--

.3

.6

27.4

472

3.0

454

.6

145

-

-

--

3.6

.9

1.9

49.0

1,200

6.5

807

1.2

205

1.3

2.4

84.1

1,800

<7.8

537

1.3

171

.8

1.7

43.7

1,130

5.7

712

1.1

194

-.

--

--

12340000--BLACKFOOT RIVER NEAR BONNER. MONT.

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

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

1

11

5

11

11

11

5

5

11

11

5

11

11

11

5

Arctopsyche grandis

._

.4

1.8

13.4

1,230

2.1

517

1.2

143

Claassenia sabulosa

.2

.9

88.5

158

.6

127

1993,1996,1998,2000,2003

_

<.l

.8

9.9

108

.5

286

.8

123

.1

.3

19.0

46.2

.4

26.3

2.8

'.2

1.3

12.0

606

1.0

413

1.0

135

.1

.5

45.2

100

.3

57.1

'.2

1.2

12.0

617

.6

398

1.0

136

.1

.5

44.0

99.0

.4

44.7
TABLE 24 105

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

September 2003 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, 2003

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Claassenia sabulosa Continued

5 .3 .1

11 329 117

Hydropsyche occidentalis

\

13 .5 .1

13 2.7 .8

13 20.6 12.0

13 1,930 1,060

13 1.9 .8

13 577 414

13 1.8 .9

13 150 116

Hydropsyche spp.

1

1

1

1

1

1

1

1

12340500- CLARK FORK ABOVE MISSOULA. MONT.

Period of record for biological data: 1997-2003

Arctopsyche grandis

3 4.5 4.0

22 1.8 .4

22 3.4 .6

22 77.6 19.5

22 2,340 476

22 6.8 1.2

22 1,400 476

22 2.0 .5

22 260 133

Claassenia sabulosa

2 1.1 .7

11 2.0 .2

11 1.1 .3

11 71.7 33.0

11 402 95.3

11 3.1 .5

11 683 75.2

11 <.4 <.3

11 363 191

Hydropsyche cockerelli

2 6.5 6.4

11 1.3 .4

.2

209

3.2

.2

1.8

14.4

1,410

1.3

480

1.3

135

.6

1.6

13.9

1,140

2.9

525

2.8

132

4.2

.7

1.6

34.4

1,030

3.7

902

1.2

189

.9

.7

.7

48.9

247

J 1.3

261

U

268

6.4

.8

.2

194

.2

1.7

14.4

1,470

1.3

466

1.2

130

-

-

--

--

--

4.2

.6

1.5

28.2

953

3.3

887

1.0

195

.4

.7

46.0

246

] 1.2

270

U

250

.8
106 Water-Quality, Bed-Sediment, and Biological Data (October 2002 through September 2003) 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 2003 Continued

Constituent

Number of 

composite Maximum Minimum 

samples

Mean Median

12340500-- CLARK FORK ABOVE MISSOULA. MONT. Continued

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Period of record for biological data: 1997-2003

Hydropsyche cockerelli Continued

11 6.0 1.8

11 96.1 29.9

11 3,590 1,400

11 10.0 4.2

11 1,890 781

11 2.4 1.4

11 237 156

Hydropsyche occidentalis

2 6.2 6.2

8 1.1 .4

8 5.5 2.1

8 76.5 30.3

8 2,400 1,450

8 10.2 4.0

8 2,460 939

8 2.4 1.6

8 257 192

12353000-- CLARK FORK BELOW MISSOULA. MONT.2

Period of record for biological data: 1986, 1990-2003

Arctopsyche grandis

3 2.6 2.4

28 1.5 .2

28 2.7 .5

28 38.0 9.4

28 1,590 343

28 3.9 .9

28 1,090 511

28 1.6 .4

28 217 106

Claassenia sabulosa

2 .8 .8

41 1.3 .1

41 1.2 .05

41 74.8 31.1

41 239 66.6

41 1.3 .1

41 168 48.9

41 .3 .1

41 286 146

Hydropsyche cockerelli

5 2.4 2.2

43 1.1 .2

43 3.4 .3

43 54.1 12.4

43 2,220 584

43 6.6 1.2

43 1,210 353

3.3

57.2

2,160

6.2

1,190

1.9

197

6.2

.7

3.4

51.4

2,060

6.8

1,840

2.0

227

2.5

.7

1.3

21.1

804

1.9

701

.9

152

.8

.5

.5

48.1

111

.4

102

.2

215

2.4

.5

1.8

30.1

1,290

2.5

752

3.2

46.0

2,070

5.7

1,130

1.9

194

.6

3.0

52.9

2,220

6.6

1,950

2.2

230

2.5

.6

1.4

19.8

718

1.8

675

.9

148

-

.4

.5

46.9

103

.3

99.0

.2

210

2.4

.5

1.8

27.5

1,320

2.3

684
TABLE 24 107

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

SQptQmbgr 2003 Continued

Constituent

Number of 

composite Maximum 

samples

Minimum Mean Median

12353000-CLARK FORK BELOW MISSOULA. MONT. 2 Continued 

Period of record for biological data: 1986,1990-2003

Hvdropsvche cockerelli Continued

Nickel

Zinc

43

43

1.9 .5

187 77.4

1.2

142

1.3

147

Hydropsyche occidentalis

Arsenic

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

1

17

17

17

17

17

17

17

17

1

1

1

1

1

1

1

1

1.1 .1

3.5 .1

38.2 13.5

1,420 482

4.2 .7

1,460 491

2.2 .5

193 112

Hydropsyche spp.

--

-

..

._

--

2.5

.4

1.4

23.8

941

2.1

841

1.0

143

.5

.8

20.8

894

1.1

756

1.1

124

.3

1.5

20.9

907

1.9

812

.9

144

--

--

Values determined by arbitrarily substituting one-half of the analytical detection limit for censored (<) values when both uncensored 

and censored values were used in determining the mean and median. When all data were less than the analytical detection limit, the 

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

analytical detection limit.

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

* U.S. GOVERNMENT PRINTING OFFICE: 2004 773-106 / 66017 Region No. 8