In cooperation with the

U.S. ENVIRONMENTAL PROTECTION AGENCY

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

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

Carlos Primo C. David

Open-File Report 00-370

U.S. Department of the Interior 

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

BRUCE BABBITT, Secretary

U.S. Geological Survey

Charles G. Groat, Director

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

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

Helena, Montana 

September 2000

For additional information write to:

District Chief 

U.S. Geological Survey 

3162 Bozeman Avenue 

Helena, MT 59601-6456

Copies of this report may be purchased from:

U.S. Geological Survey 

Branch of Information Services 

Box 25286 

Denver, CO 80225-0286
CONTENTS

Page

Abstract.................................................................................................................................................................................. I

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

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

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

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

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

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

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

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

Results........................................................................................................................................................................ 10

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

Biological data....................................................................................................................................................................... II

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

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

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

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

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

Data.........................................................._ 15

ILLUSTRATION

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

TABLES

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

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

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

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

basin, Montana............................................................................................................................................ 7

4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999........ 16

5-7. Daily streamflow and suspended-sediment data, October 1998 through September 1999, for:

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

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

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

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

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

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

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

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

Montana...................................................................................................................................................... 49

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

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

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

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

14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, August 1999...... 53

15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, August 1999.................. 54

CONTENTS iii
TABLES (Continued)

Page 

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

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

18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 1999....................................... 57

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

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

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

through September 1999............................................................................................................................ 61

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

August 1986 through August 1999...................-...................................-............. ............................. 76

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

through August 1999........................................................................................................... ................ 81

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

August 1999............................................................................................................................................... 86

CONVERSION FACTORS, ABBREVIATED WATER-QUALITY UNITS, AND ACRONYMS

Multiply________________By_______________To obtain

cubic foot per second (ft3/s)

foot (ft)

gallon (gal)

gallon (gal)

inch (in.)

inch (in.)

mile (mi)

ounce (oz)

part per million

square mile (mi2)

ton per day (ton/d)

0.028317

0.3048

3.785

3,785

25.4

25,400

1.609

28.35

1

2.59

907.2

cubic meter per second

meter (m)

liter (L)

milliliter (mL)

millimeter (mm)

micrometer (nm)

kilometer

gram (g)

microgram per gram (ng/g)

square kilometer

kilogram per day

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

°F = 9/5 (°C) + 32

Abbreviated water-quality units used in this report:

micrograms per gram

micrograms per liter 

Hg/mL micrograms per milliliter

US/cm microsiemens per centimeter at 25 degrees Celsius 

mg/L milligrams per liter

Water-year definition:

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

Acronyms used in the report:

ICAPES Inductively Coupled Argon Plasma Emission Spectroscopy

LRL laboratory reporting levels

LT-MDL long-term method detection levels

NWQL USGS National Water Quality Laboratory, Denver, Colo.

RSD relative standard deviation

SRM standard reference material

USGS U.S. Geological Survey

iv Water-Qnality, Bed-Sediment, and Biological Data (October 1998 through September 1999) and Statistical Summaries of Data for Streams in 

the Upper Clark Fork Basin, Montana
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

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

Abstract

Water, bed sediment, and biota were sampled in 

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

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

15 stations during October 1998 through September 

1999 (water year 1999). Data for 16 bed-sediment and 

15 biological stations were obtained in August 1999. 

The primary constituents analyzed were trace elements 

associated with tailings from historical mining and 

smelting activities.

Water-quality data include concentrations of 

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

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

the fine-grained and bulk fractions. Biological data 

include trace-element concentrations in whole-body 

tissue of aquatic benthic insects. Quality-assurance 

data are reported for analytical results of water, bed 

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

for the period of record at each station since 1985.

INTRODUCTION

The Clark Fork originates near Warm Springs in 

western Montana at the confluence of Silver Bow and 

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

of stream from Silver Bow Creek hi Butte to the Clark 

Fork at Milltown Reservoir, six major tributaries enter: 

Blacktail Creek, Warm Springs Creek, Little Blackfoot 

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

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

Fork basin above Missoula include irrigation, stock

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

primarily are cattle production, logging, mining, and 

recreation. Large-scale mining and smelting had been 

prevalent land uses in the upper basin for more than one 

hundred years, but are now largely discontinued.

Deposits of copper, gold, silver, and lead ores 

were extensively mined, milled, and smelted in the 

drainages of Silver Bow and Warm Springs Creeks 

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

mining also occurred in the basins of most of the major 

tributaries to the upper Clark Fork. Tailings derived 

from mineral processing commonly contain large 

quantities of trace elements such as arsenic, cadmium, 

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

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

channels, on flood plains, and in the Warm Springs 

Ponds and Milltown Reservoir. The widely dispersed 

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

elements in elevated concentrations can pose a risk to 

aquatic biota and human health because they can accumulate to potentially toxic levels.

Concern about the potential toxicity of tailings to 

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

to characterize the aquatic resources in the upper Clark 

Fork basin to guide and monitor remedial cleanup 

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

effectiveness of remediation. Water-quality data have 

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

at selected sites in the upper Clark Fork basin since 

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

Lambing and others, 1994, 1995; and Dodge and others, 1996, 1997, 1998, 1999). Trace-element data for 

bed sediment and biota (aquatic benthic insects) have

'U.S. Geological Survey, Menlo Park, Calif. Abstract
47°

114°

Base from U.S. Geological 

Survey, State base map. 

1:1,000,000,1966

EXPLANATION

12324200 STATION AND NUMBER 

461903112440701 MISCELLANEOUS SITE AND NUMBER 

STREAMFLOW GAGING 

A Continuous record 

A Periodic measurement 

WATER QUALITY, BED SEDIMENT, BIOTA 

^7 Periodic water quality 

V- Daily suspended sediment 

V~ Once-annual bed sediment 

~V Once-annual biota

46C

461903112440701 

461559112443301 ~y~ 

461415112450801 V" ) : 

Galen .Al.2323800. f

Warm Springs. >V ' o 

12323770- -5^-12323750 i. °

Opportunity'

i^viWann Springs 

12323600

10 20 MILES

10 20 KILOMETERS

Figure 1. Location of study area.

been collected intermittently since 1986 at selected 

sites as part of studies on bed-sediment contamination 

and bioaccumulation of metals conducted by the USGS 

National Research Program (Axtmann and Luoma, 

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

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

1993. an expanded sampling program for water, bed 

sediment, and biota was implemented in cooperation 

with the U.S. Environmental Protection Agency to provide systematic, long-term monitoring. In 1996, 

water-quality and daily sediment sampling in the 

expanded program was scaled back to a less extensive 

network and reduced sampling frequency. In 1997, the

water-quality network was partially restored to the pre1996 status (water-quality sampling at the Clark Fork 

below Missoula was not reactivated) and sampling frequency was increased to better quantify the seasonal 

and annual variability in selected constituents.

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

16 bed-sediment and 15 biological stations in the upper 

Clark Fork basin collected from October 1998 through 

September 1999 (water year 1999). Quality-assurance 

data are presented for water quality, bed sediment, and 

biota. Statistical summaries also are provided for

Water-quality, bed-sediment, and biological data (October 1998 through September 1999) and statistical summaries of data for streams in the 

upper Clark Fork basin. Montana
water-quality, bed-sediment, and biological data collected since 1985.

SAMPLING LOCATIONS AND TYPES OF 

DATA

Sampling stations in the upper Clark Fork basin 

are located on the Clark Fork mainstem and major tributaries from Butte to below Missoula (fig. 1). Mainstem sampling sites were selected to divide the upper 

Clark Fork into reaches of relatively uniform length, 

with each reach encompassing either a major tributary 

or depositional environment (Warm Springs Ponds and 

Milltown Reservoir). Tributaries were sampled to 

describe water-quality characteristics for major hydrologic sources in the upper basin and to provide reference comparisons to the mainstem for bed sediment 

and biota. Water-quality data were obtained periodically at 15 stations; daily suspended-sediment data 

were obtained at 3 of these stations. Trace-element 

data for 16 bed-sediment and 15 biological stations 

were obtained once-annually (table 1).

A list of properties and constituents analyzed in 

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

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

biota, and associated quality assurance for water year 

1999 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 1999 are given in tables 21-24 at 

the back of the report.

Quality assurance of data was maintained 

through the use of documented procedures designed to 

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

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

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

WATER-QUALITY DATA

Water-quality data consist of measurements of 

physical properties and concentrations of chemical and 

physical constituents analyzed in stream samples. 

Samples were collected 6 to 8 times per year on a 

schedule designed to describe seasonal and hydrologic 

variability. In addition, supplemental samples were 

collected by a contract observer at Clark Fork at Turah

Bridge, near Bonner (11 samples), Blackfoot River 

near Bonner (4 samples), and Clark Fork above Missoula (13 samples) to better define changes in trace-element concentrations and transport during extended 

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

Methods

Cross-sectional water samples were collected 

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

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

(1999). These methods provide a vertically and laterally discharge-weighted sample that is representative 

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

Sampling equipment consisted of standard USGS 

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

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

and equipped with nylon nozzles.

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

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

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

(1985). Instantaneous streamflow at the time of water 

sampling was determined at all stations, either by direct 

measurement or from stage-discharge rating tables 

(Rantz and others, 1982).

Water samples were analyzed for the constituents 

listed in table 2 by the USGS National Water Quality 

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

total-recoverable concentrations. Analytical methods 

are described by Fishman and Friedman (1989) and 

Fishman(1993).

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

periodic water-quality samples were collected. These 

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

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

the USGS sediment laboratory in Helena, Mont., 

according to methods described by Guy (1969) and 

Lambing and Dodge (1993).

SAMPLING LOCATIONS AND TYPES OF DATA
1 

=

IIi

B

S Sf

SP O 

nS

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

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

Station number 

(fig. 1)

12323230

1232325012323600

123237501232377012323800

461415112450801461559112443301461903112440701

1232420012324590123246801233150012331800

123345101233455012340000

12340500

12353000

Station name

Blacktail Creek at Harrison Avenue, at 

ButteSilver Bow Creek below Blacktail Creek, at ButteSilver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Warm Springs Creek at Warm SpringsClark Fork near GalenClark Fork below Lost Creek, near GalenClark Fork near RacetrackClark Fork at Dempsey Creek diversion, near RacetrackClark Fork at Deer LodgeLittle Blackfoot River near Garrison

Clark Fork at Goldcreek

Flint Creek near DrummondClark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, near Bonner

Blackfoot River near Bonner

Clark Fork above MissoulaClark Fork below Missoula4

Continuousrecord 

stream flow

- 

10/83-P

07/88-P

03/72-09/79, 

04/93-P

10/83-P

07/88-P

"~"

10/78-P10/72-P10/77-P

08/90-P

04/93-P

10/72-P

03/85-P

10/39-P

03/29-P

10/29-P

Periodic water 

quality1

03/93-08/95, 

12/96-P

03/93-08/95, 

12/96-P

03/93-08/95, 

12/96-P

03/93-P

03/93-P

07/88-P

"-"

03/85-P03/85-P03/93-P03/85-P

03/93-P

03/85-P03/85-P03/85-P

07/86-PJ

03/85-09/95

Daily suspended 

sediment

"*

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

-

-

"

03/85-08/86, 

04/87-P

~

~"*"

03/85-P

07/86-04/87, 

06/88-09/95

07/86-04/87, 

06/88-01/96, 

03/96-P

"

Fine-grained 

bed sediment2

 "

07/92-P07/92-P

08/95, 08/97, 08/99

08/87, 

08/91-P08/96-P

08/96-P08/96-P

08/86,08/97, 

08/90-P

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

08/98

07/92-P

08/86, 08/89, 

07/92-P

08/86, 08/87, 

08/91-P

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

08/91-P

08/86, 

08/91-P

08/86, 08/87, 

08/91, 

08/93-96, 08/98-P

08/97-P

08/86, 

08/90-P

Bulk bed sediment2

"

"

08/93-08/95, 

08/97-P

08/93, 

08/95-P

08/95, 08/97, 08/99

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

08/96-P

08/93-P

08/94, 08/98

08/93-P

08/93-P08/93-P

08/93-P08/93-P

08/93, 08/94, 08/99

08/97-P

08/93-P

Biota2

~

~

07/92, 08/94, 

08/95, 08/97-P

07/92-P

08/95, 08/97, 08/99

08/87, 

08/91-P

08/96-P08/96-P

08/96-P

08/86, 08/87, 

08/90-P

08/87, 08/94 

08/98

07/92-P

08/86, 

07/92-P

08/86, 

08/9 1-P

08/87, 

08/91-P

08/86, 

08/91-P

08/86. 08/87, 

08/91,08/93, 

08/96, 08/98

08/97-P

08/86, 

08/90-P

t, I

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

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

laboratory analyses of trace elements.

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

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

Water

Property

Streamflow

Specific conductance

pH

Temperature

Constituent

Hardness

Calcium

Magnesium

Arsenic

Cadmium

Copper

Iron

Lead

Manganese

Zinc

Suspended sediment

Bed sediment

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Biota

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

At the three daily suspended-sediment stations 

(table 1), suspended-sediment samples were collected 

2 to 8 times per week. These samples were collected 

by local contract observers using the depth-integration 

method at a single vertical near mid-stream. The samples were analyzed for suspended-sediment concentration and were used to determine daily mean 

suspended-sediment concentrations according to methods described by Porterfield (1972).

Results

Water-quality data for samples collected periodically during October 1998 through September 1999 

(water year 1999) are presented in table 4. The types of 

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

results for chemical constituents and suspended sediment.

Daily streamflow and suspended-sediment data 

for water year 1999 at the three daily suspended-sediment stations are given in tables 5 through 7. Monthly 

descriptive statistics for each parameter are provided 

along with totals for the annual discharge of water and 

suspended sediment.

Quality Assurance

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

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

Harr (1990), Edwards and Glysson (1999), Knapton 

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

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

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

(1992). Quality-assurance procedures used by the 

Montana District sediment laboratory are described by 

Lambing and Dodge (1993).

The quality of analytical results reported for 

water-quality samples was evaluated by quality-control 

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

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

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

about 5 percent of the total number of water-quality 

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

number of water-quality samples.

In addition to quality-control samples submitted 

from the field, internal quality-assurance practices at 

the NWQL are performed systematically to provide 

quality control of analytical procedures (Pritt and 

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

samples, deionized-water blanks, or spiked samples at

WATER-QUALITY DATA 5
a proportion equivalent to at least 10 percent of the 

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

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

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

Inland Water, and the Branch of Quality Systems to 

assess analytical performance.

Replicate data can be obtained in different ways 

to provide an assessment of precision (reproducibility) 

of analytical results. Replicate samples are two or 

more samples considered to be essentially identical in 

composition. Replicate samples can be obtained in the 

field by either repeating the collection process to obtain 

two or more samples or by splitting a single sample 

into two or more subsamples which are then analyzed 

separately (field replicate). Likewise, a single sample 

can be analyzed two or more times in the laboratory to 

obtain a measure of analytical variability (laboratory 

replicate).

Precision of analytical results for field replicates 

is affected by numerous sources of variability within 

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

To provide data on precision for samples exposed to all 

sources of variability, chemical-replicate samples were 

obtained in the field by splitting a composite stream 

sample. Suspended-sediment replicate samples were 

obtained in the field by concurrently collecting two 

independent cross-sectional samples. Analyses of 

these field replicates indicate the reproducibility of 

environmental data that are affected by the combined 

variability potentially introduced by field and laboratory processes.

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

individual sample selected randomly in the laboratory 

from the group of samples comprising each analytical 

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

beginning and end of each analytical run to provide 

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

by field collection and processing of samples.

Spiked samples are used to evaluate the ability of 

an analytical method to accurately measure a known 

amount of analyte added to a sample. Because some

constituents in stream water can potentially interfere 

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

determine whether such effects are causing inaccurate 

analyses. Deionized-water blanks and aliquots of 

stream samples were spiked in the laboratory with 

known amounts of the same trace elements analyzed in 

water samples. Analyses of spiked blanks indicate if 

the spiking procedure and analytical method are within 

control for a water matrix that is presumably free of 

chemical interference. Analyses of spiked aliquots of 

stream samples indicate if the chemical matrix of the 

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

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

Blank samples of deionized water were routinely 

analyzed to identify the presence and magnitude of 

contamination that potentially could bias analytical 

results. The particular type of blank sample routinely 

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

deionized water that are certified as trace-element free 

and are processed through the sampling equipment 

used to collect stream samples. These blanks are then 

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

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

exist.

All water samples were handled in accordance 

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

laboratory handling. All samples submitted from a 

sampling episode were stored and analyzed as a discrete sample group, independent of other samples submitted to the NWQL. Therefore, statistical 

descriptions of quality-control data generated for this 

program are directly applicable to the analytical results 

for stream samples reported herein.

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

for the expanded long-term monitoring program that 

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

for identifying questionable data by establishing 

acceptable limits for precision and bias of laboratory 

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

6 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
Data that did not meet the objectives were evaluated for 

acceptability, and corrective action was taken, when 

appropriate.

Changes in analytical methods during the year 

resulted in the modification of the minimum reporting 

levels for total-recoverable cadmium, total-recoverable 

iron, total-recoverable and dissolved manganese, and 

total-recoverable and dissolved zinc. Because these 

changes occurred part way through the year, the minimum reporting levels for these constituents are represented as a range of detectability in table 3. The 

minimum reporting levels for dissolved magnesium, 

dissolved iron, and dissolved lead also changed, but 

near the beginning of the year; therefore, these minimum reporting levels remained constant throughout 

the year.

During water year 1999, the NWQL began 

implementation of a new, statistically based convention 

for establishing reporting levels and for reporting lowconcentration data (Childress and others, 1999). Quality-control data are collected on a continuing basis to 

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

values are re-evaluated each year and, consequently, 

may change from year to year. The methods are 

designed to limit the possible occurrence of a false positive or false negative error to 1 percent or less. 

Accordingly, concentrations are reported as <LRL for 

samples in which the analyte was either not detected or 

did not pass identification criteria. Analytes that are 

detected at concentrations between the LT-MDL and 

LRL and that pass identification criteria are estimated. 

Estimated concentrations are noted with a remark code 

of "E." These data need to be used with the understanding that their uncertainty is greater than that of 

data reported without the "E" remark code.

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

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

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

an individual sample (laboratory replicates). The difTable 3. Data-quality objectives for analyses of water-quality samples collected in the upper Clark Fork basin, Montana 

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

Data-quality objectives

Detectability

Constituent

Calcium, dissolved

Magnesium, dissolved

Arsenic, total recoverable

Arsenic, dissolved

Cadmium, total recoverable

Cadmium, dissolved

Copper, total recoverable

Copper, dissolved

Iron, total recoverable

Iron, dissolved

Lead, total recoverable

Lead, dissolved

Manganese, total recoverable

Manganese, dissolved

Zinc, total recoverable

Zinc, dissolved

Sediment, suspended

Sediment, suspended (percent finer than 0 062 mm)

Precision

Maximum relative 

Laboratory standard deviation of 

reporting laboratory replicate 

level analyses,

0.02

.004

1

1

.1-1

.1

1

1

10-14

10

1

.5

3-10

1-4

10-40

1-20

1

1

mg/L

mg/L

ug/L

Hg/L

ug/L

ug/L

ug/L

ug/L

Hg/L

ug/L

ug/L

Hg/L

ug/L

ug/L

ug/L

ug/L

mg/L

percent

in percent

20

20

20

20

20

20

20

20

20

20

20

20

20

20

20

20

-

-

Bias

Maximum 

deviation of 

spike recovery, 

in percent

-

-

25

25

25

25

25

25

25

25

25

25

25

25

25

25

-

-

WATER-QUALITY DATA
ferences in concentration between replicate analyses 

can be used to estimate a standard deviation according 

to the following equation (Taylor, 1987):

^ _

(1)

where

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

d = difference in concentration between each

pair of replicate analyses, and 

k = number of pairs of replicate analyses.

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

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

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

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

RSD = f xlOO (2)

x

where

RSD = relative standard deviation,

S = standard deviation, and

x - mean of all replicate concentrations.

Paired analyses of field replicates are presented 

in table 8. The precision estimated for each constituent 

based on these paired results, which include both field 

and laboratory sources of variability, is reported in 

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

are rounded to standard USGS reporting levels for the 

particular constituent and its analytical method 

(Timme, 1994).

Data-quality objectives for precision are not 

directly applicable to field replicates because of the 

inability to determine whether the variability results 

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

in table 9 to illustrate overall reproducibility of environmental data that incorporates both field and laboratory sources of variability. Relative standard 

deviations estimated from differences in analytical 

results between field replicates were within 12 percent 

for all constituents.

Analytical precision for chemical constituents 

based on replicate laboratory analyses of individual 

samples, which includes only laboratory sources of 

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

based on unrounded values stored in laboratory data 

files.

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

estimates for laboratory-replicate analyses (table 10) 

were within the 20-percent relative standard deviation 

limit for all constituents except dissolved zinc. The 

exceedance of dissolved zinc was a result of poor comparison in 3 of the 10 laboratory replicate sample sets. 

The poor precision data for dissolved zinc was random 

and showed no systematic patterns.

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

The data-quality objective for acceptable spike 

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

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

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

according to equation 3. If the spike recovery for a 

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

the instrument was recalibrated and the entire sample 

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

the extent possible. Results of recovery efficiency for 

individual trace elements in spiked deionized-water 

blanks and spiked stream samples are presented in 

tables 11 and 12, respectively.

The mean spike recovery for deionized-water 

samples spiked with trace elements ranged from 93.3 to 

108.9 percent. The mean spike recovery for spiked 

stream samples ranged from 96.2 to 105.2 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.

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
Spike recovery in percent = spiked sample concentration - unspiked sample concentration x JQQ

spike concentration

(3)

High or low bias is indicated if the confidence 

interval does not include 100 percent recovery. All 

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

percent. Because the mean spike recoveries met dataquality objectives, no adjustments were made to analytical results for stream samples on the basis of spike 

recoveries.

Analytical results for field blanks are presented 

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

(LRL) for the analytical method indicates that the 

entire process of sample collection, field processing, 

and laboratory analysis is presumably free of significant contamination. If detectable concentrations in 

field blanks were equal to or greater than twice the LRL 

(typical measurement precision at the detection level), 

the concentrations were noted during data review. 

Analytical results from the field blank for the next sample set is evaluated for a consistent trend that may indicate systematic contamination. Sporadic, infrequent 

exceedances of twice the LRL probably represent random contamination or instrument calibration error that 

is not persistent in the process and which is not likely 

to cause significant positive bias in a long-term record 

of analytical results. However, if concentrations for a 

particular constituent exceed twice the LRL in field 

blanks from two consecutive field trips, blank samples 

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

order to identify the source of contamination.

Constituent concentrations in field blanks were 

almost always less than the LRL. There was only one 

occurrence of a value exceeding twice the minimum 

reporting level (iron), and there were no occurrences of 

detectable concentrations for any trace element in two 

consecutive blank samples. Therefore, the analytical 

results for field blanks indicate no systematic contamination that would bias the reported water-quality data 

for stream samples.

BED-SEDIMENT DATA

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

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

Bed-sediment samples are collected once-annually 

during low, stable flow conditions to facilitate data 

comparisons among years.

Methods

Bed-sediment samples were collected in August 

1999 using protocols described by E.V. Axtmann (U.S. 

Geological Survey, written commun., 1994). Samples 

were collected from the surfaces of streambed deposits 

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

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

stream. Three composite samples of fine-grained bed 

sediment and two composite samples of bulk bed sediment were collected at each site.

Individual samples of fine-grained bed sediment 

were collected by scooping material from the surfaces 

of three to five randomly selected deposits along pool 

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

This collection process was repeated three times to 

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

bed sediment in each composite sample that was finer 

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

mL polyethylene bottle and transported to the laboratory on ice.

Individual samples of bulk bed sediment also 

were collected by scooping material from the surfaces 

of three to five randomly selected deposits. Because 

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

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

generally were composed of particles smaller than 

about 10 mm in diameter. The individual unsieved 

samples were composited into an acid-washed polyethylene bottle and transported to the laboratory on ice.

Bed-sediment samples were prepared for analysis at the USGS National Research Program laboratory 

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

using an acid-washed ceramic mortar and pestle.

BED-SEDIMENT DATA
Duplicate aliquots of approximately 0.6 g of sediment 

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

nitric acid reflux according to methods described by 

Luoma and Bryan (1981). Two aliquots were similarly 

digested from the single composite sample of bulk bed 

sediment. After a digestion period of up to several 

weeks, the aliquots were evaporated to dryness on a hot 

plate. The dry residue was redissolved with 20 mL of 

0.6 N (normal) hydrochloric acid. The reconstituted 

aliquots then were filtered through a 0.45-um filter 

using a syringe and in-line disposable filter cartridge. 

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

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

solutions were analyzed for cadmium, chromium, copper, iron, lead, manganese, nickel, silver, and zinc 

using Inductively Coupled Argon Plasma Emission 

Spectroscopy (ICAPES).

Results

Concentrations of trace elements measured in 

samples of fine-grained and bulk bed sediment collected during August 1999 are summarized in tables 14 

and 15, respectively. Liquid-phase concentrations, in 

ug/mL, that were analyzed in the reconstituted aliquots 

of digested bed sediment were converted to solid-phase 

concentrations, in ug/g, using the following equation:

ug/mL x volume of digested sample, in mL ' * * /4)

dry weight of sample, in g x dilution ratio

The reported solid-phase concentrations in table 14 

and 15 are the means of all analyses of replicate 

aliquots from each composite sample collected at the 

site. Because the conversion from liquid-phase to 

solid-phase concentration is dependent on both the 

dilution ratio and the dry weight of the sample, 

minimum reporting levels for some trace elements 

may differ among stations and among years.

Quality Assurance

The protocols for field collection and processing 

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

and processing equipment was acid-washed and rinsed 

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

equipment was given a final rinse onsite with stream 

water. Sampling equipment that was reused at each site 

was rinsed between sites with 10-percent nitric acid, 

deionized water, and stream water. Separate sieves 

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

between-site cleaning.

Quality assurance of analytical results for bed 

sediment included laboratory instrument calibration 

with standard solutions and analysis of quality-control 

samples designed to identify the presence and magnitude of bias (E.V. Axtmann, U.S. Geological Survey, 

written commun., 1994). Quality-control samples consisted of standard reference materials and procedural 

blanks. Each type of sample was analyzed in a proportion equivalent to about 10 to 20 percent of the total 

number of bed-sediment samples.

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

SRMs are used to indicate the reproducibility of analytical results and the ability of the method to accurately 

measure a known quantity of a constituent. Recovery 

efficiency of trace-element analyses of SRMs for bed 

sediment is summarized in table 16. Two SRMs consisting of agricultural soils representing low and high 

concentrations of trace elements were analyzed to test 

recovery efficiency for a range of concentrations generally similar to those occurring in the upper Clark 

Fork basin. The digestion process used to analyze bedsediment samples is not a "total" digestion (does not 

liberate elements associated with crystalline lattices); 

therefore, 100-percent recovery may not be achieved 

for elements strongly bound to the sediment. The percent recovery of trace elements in SRMs when using 

less than a total digestion is useful to indicate which 

trace elements display strong sediment-binding characteristics and whether analytical recovery is consistent 

between multiple sets of analyses.

Although data-quality objectives have not been 

established for bed sediment, percent recoveries are 

shown in table 16 to illustrate analytical performance. 

Elements with mean recoveries outside a 25-percent 

deviation from complete (100 percent) recovery were 

cadmium and chromium for the low-concentration 

range (SRM 2709), and chromium for the high-concentration range (SRM 2711). Silver was below the analytical detection limit in the low-range SRM (2709). 

Chromium recovery was consistently low for both 

SRM 2709 and 2711 (65.6 and 57.9 percent, respectively). The reason for the lack of measurable recover10 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
ies is believed to be the result of analyzing 

concentrations very close to the detection limit, coupled with signal enhancement resulting from matrix 

interference. No adjustments were made to trace-element concentrations in bed-sediment samples on the 

basis of recovery efficiencies.

Procedural blanks for bed-sediment samples 

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

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

added quantitatively to the dry residue to obtain the 

same dilution ratio as that used in the analysis of bed 

sediment. Procedural blanks, therefore, represent the 

same chemical matrix as the reagents used to digest and 

reconstitute bed-sediment samples. Analytical results 

for procedural blanks can indicate the presence and 

magnitude of potential contamination associated with 

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

blanks for bed sediment are in table 17.

Analytical results of procedural blanks are 

reported as a liquid-phase concentration, in /J.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 p.g/g, relative to the ambient concentration of the trace element in bed-sediment samples. 

Because sample weights of individual aliquots may 

vary, the relative significance of blank concentrations 

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

solid-phase concentration, then the blank concentration 

is subtracted to remove potential contamination bias. 

Almost all procedural blanks had concentrations less 

than analytical detection levels. Only copper in one 

procedural blank sample slightly exceeded the calculated limit of detection. None of the detectable concentrations in blanks were greater than 10 percent of the 

ambient concentration; therefore, no adjustments were 

made to trace-element concentrations in bed-sediment 

samples on the basis of procedural blanks.

BIOLOGICAL DATA

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

aquatic benthic insects. Insect samples are collected 

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

Methods

Insect samples were collected using protocols 

described in Hornberger and others (1997). Immature 

stages of aquatic benthic insects were collected using a 

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

of individuals was collected to provide sufficient mass 

for analysis. Targeted taxa for collection were Hydropsyche spp., Brachycentrus spp., and Arctopsyche 

grandis of the Order Trichoptera (caddisflies), and 

Claassenia sabulosa of the Order Plecoptera (stoneflies). Samples of each taxon were stored separately, 

by genus, in acid-washed plastic containers. Samples 

were frozen with dry ice within 1 hour of collection in 

a small amount of ambient river water. In previous 

years (1986-98), benthic insects were depurated for a 

period of 6-8 hours in an effort to evacuate gut contents. In 1998, a comparison of samples collected 

using both methods showed no significant difference in 

metal concentrations in benthic insects, with the exception of copper. Average copper concentrations in depurated samples were 8-25 percent lower than samples 

frozen within one hour of collection (M.I. Hornberger, 

unpub. data, 2000). The change in the field protocol 

minimizes the chance of metal loss through cell membranes and is consistent with methods established by 

Cain and Luoma( 1998).

Insect samples were processed and analyzed at 

the USGS National Research Program laboratory in 

Menlo Park, Calif. Insects were thawed and rinsed 

with ultra-pure deionized water to remove particulate 

matter, then sorted to their lowest possible taxonomic 

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

composited into replicate subsamples. Subsamples 

were placed in tared scintillation vials and oven-dried 

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

dry weight and digested by reflux using concentrated 

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

insect samples were evaporated to dryness on a hot 

plate. The dry residue was reconstituted in 0.6 N 

hydrochloric acid, filtered through a 0.45-jim filter, and 

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

BIOLOGICAL DATA
Results

Concentrations of trace elements in whole-body 

tissue of aquatic insects collected during August 1999 

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

sites reflects differences in insect abundance, with the 

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

analyzed in the reconstituted samples were converted 

to solid-phase concentrations using equation 4. As 

with bed sediment, minimum reporting levels may differ among sites as a result of variable sample weights. 

In general, the smaller the biological sample weight (a 

function of insect abundance), the higher the minimum 

reporting level. Therefore, higher minimum reporting 

levels do not necessarily imply a higher trace-element 

concentration in tissue.

Two species of Hydropsyche were targeted for 

collection in this study due to their occurrence at most, 

but not all, sites: Hydropsyche occidentalis and 

Hydropsyche cockerelli. Hydropsyche species that 

could not be positively identified were considered to 

belong to the morosa group and are categorized as 

Hydropsyche spp. or Hydropsyche morosa group. 

Arctopsyche grandis and Claasenia sabulosa also were 

collected, where available, to represent additional 

insect taxa that are fairly widely distributed in the 

upper Clark Fork basin.

Quality Assurance

The protocols for field collection and processing 

of biota samples are designed to prevent contamination 

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

processing equipment were employed in all sample 

collection. Equipment was acid-washed and rinsed in 

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

ambient stream water at each new mainstem station. 

New nets were used for the tributary stations. Biota 

samples were collected along an increasing concentration gradient to minimize effects from potential stationto-station carryover contamination.

Quality assurance of analytical results for biota 

samples included laboratory instrument calibration 

with standard solutions and analyses of quality-control 

samples designed to identify the presence and magnitude of bias. Quality-control samples consisted of 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 

recoveries were within 10 percent of complete (100 

percent) recovery for all trace metals, except chromium. A slightly low bias (confidence interval does 

not include 100 percent) is indicated for manganese 

and nickel and a slightly high bias is indicated for cadmium and lead. A higher bias was shown for chromium, which may have resulted because of 

interelement matrix interference. No adjustments were 

made to the trace-element concentrations for the insect 

samples on the basis of recovery efficiency.

Results of trace-element analyses of procedural 

blanks for biota are in table 20. Procedural blanks for 

biota consisted of the same reagents used to digest and 

reconstitute tissue of aquatic insects. The blanks were 

analyzed undiluted at a proportion of one blank per 

site. Analytical results for blanks indicated no significant contamination bias. With the exception of iron, all 

concentrations in the blanks were below detection levels. The detectable concentrations are within the range 

of instrument variability and are insignificant in relation to the measured concentrations in the insect samples; thus, no adjustments were made to trace-element 

concentrations in biota.

STATISTICAL SUMMARIES OF DATA

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

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

summaries include the period of record, number of 

samples, maximum, minimum, mean, and median of 

concentrations.

Statistical summaries of water-quality data (table 

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

period of record. They do not include supplemental 

single-vertical samples collected by a contract observer 

at Clark Fork at Turah Bridge near Bonner, Blackfoot 

River near Bonner, and Clark Fork above Missoula 

from 1997 to 1999. Inclusion of supplemental sample 

results would disproportionately skew the long-term 

statistics at these three sites relative to the other sites in

12 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
the network. Statistical summaries of bed-sediment 

(table 22 and 23) and biological data (table 24) are 

based on results of samples collected once-annually 

during the indicated years. Because not all stations 

were sampled for bed sediment and biota every year, 

these data do not represent a consecutive annual record.

Sample sizes and statistics for bed-sediment data 

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

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

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

individual years rather than the combined annual mean 

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

all years. The statistics for biota describe the full range 

of trace-element concentrations measured among all 

available composite samples. The abundance of 

aquatic insects at a particular site in a given year limits 

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

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

provided only as a general indication of the range of 

detection.

The presence or absence of insect species at a 

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

record. Because Hydropsyche insects were not sorted 

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

results of all Hydropsyche species combined. At some 

sites, statistics for the Hydropsyche morosa group are 

based on the combined results for two or more species 

because these samples could not be identified clearly to 

the species, but had morosa characteristics.

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treatment, and analysis of water samples, Montana 

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selected tributaries from Deer Lodge to Missoula, 

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

____1990, Water-quality data (October 1988 through 

September 1989) and statistical summaries (March 

1985 through September 1989) for the Clark Fork and 

selected tributaries from Galen to Missoula, Montana: 

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

1991, Water-quality and transport characteristics of 

suspended sediment and trace elements in streamflow 

of the upper Clark Fork basin from Galen to Missoula, 

Montana, 1985-90: U.S. Geological Survey WaterResources Investigations Report 91-4139, 73 p.

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

for laboratory analysis of suspended-sediment samples 

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

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

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

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

biological data (October 1993 through September 

1994) and statistical summaries of data for streams in 

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

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

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

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

biological data (October 1992 through September 

1993) and statistical summaries of water-quality data 

(March 1985 through September 1993) for streams in 

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

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

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

assessment of the form of trace metals in oxidized 

estuarine sediments employing chemical extractants: 

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

Porterfield, George, 1972, Computation of fluvial-sediment 

discharge: U.S. Geological Survey Techniques of 

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

66 p.

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

assurance/quality control manual National Water 

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

Report 92-495, 33 p.

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

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

631 p.

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

measurements: Chelsea, Mich., Lewis Publishers, 

328 p.

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

Services Catalog: U.S. Geological Survey Open-File 

Report 94-304, 103 p.

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

recommended methods for water-data acquisitionChap. 5, Chemical and physical quality of water and 

sediment: Office of Water Data Coordination, 193 p.

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

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

U.S. Geological Survey Open-File Report 90-140,71 p.

14 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
DATA

DATA 15
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999

[Abbreviations: ft3/s, cubic feet per second; °C, degrees Celsius; E, estimated; (ig/L, micrograms per liter; (iS/cm, microsiemens per centimeter at 25 °C; 

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

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

Date

NOV 1998

17...

FEB 1999

22..,

APR

27...

MAY

12...

30...

JUN

22..

AUG

12...

Time

0835

1000

1020

1425

1015

0845

1115

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

taneous onsite (standard water 

(frVs) (nS/cm) units) (°C)

8.2 286 79 4.5

6.1 294 8.2 3.0

14 236 8.0 7.0

15 231 8.1 9.5

31 185 7.7 6.5

13 237 7.8 11.5

83 283 8.1 12.5

Hardness, 

total 

(mg/L as 

CaCOj)

110

120

93

89

73

97

110

Calcium, 

dissolved 

(mg/L)

32

34

27

26

21

28

31

Magnesium, 

dissolved 

(mg/L)

7.8

8.4

6.5

6.2

5.0

6.7

7.6

Arsenic, 

total 

recoverable

2

2

4

4

8

7

5

Date

NOV 1998

17...

FEB 1999

22...

APR

27...

MAY

12...

30...

JUN

22...

AUG

12...

Arsenic, 

dissolved

(Mg/L)

2

2

2

3

5

6

3

Cadmium, ,. .. . Copper, total Cadmium, t(J£,

recoverable <SS°/iT recoverable (ng/L) vev (tlg/L}

<l <0.1 2

<1 <.l 2

<1 1 8

<1 <.l 5

<1 <.l 14

<1 <.l 5

<1 <.l 6

Copper, 

dissolved

(HB/L)

2

1

3

3

5

4

3

Iron, 

total 

recoverable

(Mg/L)

260

250

814

471

1,280

861

449

Iron, 

dissolved

(ng/L)

100

42

200

180

260

330

100

Lead, 

total 

recoverable 

(ng/L)

<1

<1

5

<1

3

<1

1

Date

NOV 1998

17...

FEB 1999

22...

APR

27...

MAY

12...

30...

JUN

22...

AUG

12...

Lead, 

dissolved

(Mg/L)

<0.5

<.5

.5

<5

<5

<5

<5

MneT Man^ Zinc' 

total nese- total recoverable dfi0'v?J recoverable

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

40 40 <10

40 38 <10

60 35 E21

41 29 <40

110 62 <40

92 71 <40

51 39 <40

Zinc, 

dissolved

(Mg/L)

<20

<20

<20

<20

<20

<20

3

Sediment, 

suspended 

(mg/L)

2

5

39

4

29

8

8

Sediment 

discharge, 

suspended 

(ton/d)

0.04

.08

1.5

.16

2.4

.28

18

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

59

94

92

97

81

93

84

16 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
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued) 

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

Date

NOV 1998

17...

FEB 1999

22...

APR

27...

MAY

12...

30...

JUN

22...

AUG

12...

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

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

"me taneous onsite (standard water (mE/Las , «! 

(ffYs) GiS/cm) units) (°C) CaCOj) \.mSM

1000 28 503 7.6 7.0 160 46

1115 21 514 7.6 6.0 170 47

1135 30 422 7.7 10.0 140 40

1340 30 414 7.8 10.5 140 39

1150 75 300 7.7 8.5 110 31

1015 29 447 7.6 14.0 150 42

1145 30 457 7.7 16.0 150 44

Magnesium, 

dissolved 

(m£/L)

12

12

10

9.7

7.4

10

11

Arsenic, 

total 

recoverable

10

10

9

8

20

11

11

Date

NOV 1998

17..

FEB 1999

22..

APR

27...

MAY

12...

30..

JUN

22...

AUG

12...

Arsenic, Cadmium, Cadmium, C° ?r' Copper, ! '

dissolved total ., dissolved tot"1 ., dissolved total ., " cecoverflble «».MW»»»,U recoverable * «« «»,u recoverflble

(ME/L) ^^ ' (ME/L) "1|* ' (ME/L)

622 73 14 650

62 .9 82 12 820

6 <l .7 41 13 670

7 <1 .7 40 14 583

13 2 .9 130 51 1,330

911 41 19 549

811 55 33 335

Iron, 

dissolved 

(^E/L)

35

34

74

72

120

81

23

Lead, 

total 

recoverable

9

10

5

4

20

3

5

Date

NOV 1998

17...

FEB 1999

22...

APR

27...

MAY

12...

30...

JUN

22...

AUG

12...

Lead, MneT M^~ ?»< .?" . Sediment,

d^f recoverable -£- -^ ^ ^^ (Hg/L) (ME/M (ME/M

<.5 440 410 540 500 14

<.5 410 390 500 430 20

<.5 419 390 254 210 13

<.5 409 390 265 220 11

.9 358 300 352 240 35

<.5 520 510 398 370 6

<.5 245 234 396 337 6

Sediment 

discharge, 

suspended 

(ton/d)

1.1

1.1

1.1

.89

7.1

.47

.49

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

88

82

85

84

83

94

98

TABLE 4 17
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

12323600-SILVER BOW CREEK AT OPPORTUNITY, MONT.

Date

NOV 1998

17...

FEE 1999

22...

APR

27...

MAY

12...

30...

JUN

04...

22...

AUG

12...

Time

1120

1245

1245

1220

1330

0940

1125

1345

Streamflow. 

instantaneous

(frVs)

45

36

72

67

189

207

88

37

Specific 

conductance, 

onsite 

(US/cm)

486

517

348

369

330

266

329

369

pH, Temper- Hardness, Calcium 

onsite ature, total dissolved 

(standard water (ing/Las Su 

units) (°C) CaC03) (m8/L)

84 2.5 170 50

8.2 1.5 180 54

8.8 10.5 130 38

8.6 9.5 130 39

8.0 5.0 130 38

7.9 8.5 98 30

8.3 11.5 130 38

8.9 18.0 130 38

Magnesium, 

dissolved 

(mg/L)

11

12

8.2

8.4

74

5.6

78

8.2

Arsenic, 

total 

recoverable

(HB/L)

14

19

16

12

120

60

13

32

Date

NOV 1998

17...

FEE 1999

22...

APR

27...

MAY

12...

30...

JUN

04...

22...

AUG

12...

Arsenic, 

dissolved

(HE/L)

8

10

9

10

11

10

9

14

Cadmium, 

total 

recoverable

2

2

1

1

7

4

<1

2

Cadmium, 

dissolved

1

2

.5

.6

.9

1

.7

.9

Copper, runner Ir°n' 

total dl 1 ed total d recoverable jr ^, , recoverable 

(Hg/L) w& ' (Hg/L)

100 37 490

160 32 910

96 44 782

83 34 608

1,200 61 9,320

620 62 4,990

80 34 478

340 63 1,490

Iron,

10

E9

26

22

100

120

19

15

Lead, 

total 

recoverable

(^ig/L)

12

22

15

10

310

130

9

49

Date

NOV 1998

17...

FEE 1999

22..

APR

27...

MAY

12..

30...

JUN

04..

22...

AUG

12...

Lead, 

dissolved

(ME/L)

<5

<.5

<.5

<.5

2

3

<.5

5

Manganese, 

total 

recoverable

490

570

359

386

1,690

884

314

598

Manganese, 

dissolved

(HE/L)

470

520

280

330

650

420

280

430

SS disced S^ '- 

recoverable (,E/D -J--

530 430 9

560 430 21

250 100 19

260 130 13

1,720 290 491

1,000 290 196

237 160 13

533 94 32

Sediment 

discharge, 

suspended 

(ton/d)

1.1

2.0

3.7

2.4

251

110

3.1

3.2

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

86

87

91

93

53

47

74

94

18 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
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

12323750-SILVER BOW CREEK AT WARM SPRINGS, MONT.

Date

NOV 1998

17...

FEE 1999

22..

APR

27..

MAY

11...

27..

JUN

10..

22..

AUG

13...

Time

1250

1325

1345

0950

1530

1040

1320

1115

Streamflow, Specific pH, Temper- Hardness, Calcium 

instan- conductance, onsite a hire, total dissolved' 

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

(ft3/s) (nS/cm) units) (°C) CaCO3) W&^>

74 535 8.9 3 5 220 62

59 602 8.8 3.5 250 73

112 427 8.5 12.0 160 47

128 425 8.4 7.0 160 45

263 287 8.8 15.0 110 31

288 306 9.0 8.0 120 35

252 249 9.1 13.0 97 28

53 425 9.3 17.0 180 51

Magnesium, 

dissolved 

(mg/L)

16

17

11

11

7.5

7.9

6.6

12

Arsenic, 

total 

recoverable

19

13

25

22

38

27

26

32

Date

NOV 1998

17...

FEE 1999

22...

APR

27...

MAY

11...

27...

JUN

10...

22...

AUG

13...

Arsenic, 

dissolved 

(ng/L)

15

11

21

22

28

23

25

32

ca-: <%= c-r', dSK <- ,

recoverable j l£j recoverable (eft.) recoverable

<1 <1 6 4 170

<1 <1 13 7 170

<1 <.l 13 6 368

<1 <.l 11 5 312

<1 <.l 22 7 909

<1 <.l 14 8 269

<l <.l 11 7 206

<1 <1 5 3 137

Iron, 

dissolved

(ng/L)

<10

<10

19

19

35

22

24

19

Lead, 

total 

recoverable

(ng/L)

<1

<1

2

2

5

2

1

<1

Date

NOV 1998

17...

FEE 1999

22..

APR

27..

MAY

11..

27..

JUN

10..

22..

AUG

13...

Lead, 

dissolved

<.5

<.5

<5

<.5

<.5

<.5

<.5

<5

JL & & * @

90 40 10 <20 3

200 120 40 E17 5

183 120 E30 <20 12

111 76 <40 E8 10

120 34 E23 <20 44

135 97 <40 <20 7

145 73 <40 <20 7

121 58 <40 2 3

Sediment 

discharge, 

suspended 

(ton/d)

0.60

.80

3.6

3.5

31

5.4

4.8

.43

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

91

82

95

92

86

86

87

87

TABLE 4 19
Table 4. Water-quality data for the upper Clark Fork basin. Montana, October 1998 through September 1999 (Continued)

12323770-WARM SPRINGS CREEK AT WARM SPRINGS, MONT.

Date

NOV 1998

17..

APR 1999

27...

MAY

27..

JUN

10...

22...

AUG

12...

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

Ti instan- conductance, onsite ature, total Hi«Milv«J sium, total 

taneous onsite (standard water (mg/Las uiwuiveu dissolved recoverable 

(ftVs) (|jS/cin) units) (°C) CaCO3) l^M (mg/L) (ng/L)

1220

1430

1430

1125

1210

1415

53 342 8.6 3.0 160 50 9.9 4

48 338 8.5 11.0 160 49 10 5

230 156 8.2 10.5 72 22 3,9 12

116 228 8.2 7.0 110 33 6.2 5

246 144 8.0 9.5 66 20 3.6 5

47 266 8.7 15.0 120 37 7.1 6

Date

NOV 1998

17...

APR 1999

27...

MAY

27...

JUN

10...

22...

AUG

12...

Arsenic, 

dissolved

(Mg/L)

2

4

6

4

4

5

Cadmium, Cadmium, C°PP?r' Copper, ! n.' Iron, *£$ 

referable * *- referable referable "? referable (Mg/L) IMPM (HE/L) IMPM (ng/L) IMPM <ng/L>

<1 <1 2 2 40 E7 <1

<1 <.l 9 2 122 E7 <1

<1 <1 61 5 1,070 15 6

<1 <.l 12 2 218 12 1

<1 <.l 19 3 461 11 2

<1 <1 8 2 84 13 <1

Date

NOV 1998

17..

APR 1999

27..

MAY

27...

JUN

10...

22...

AUG

12...

Lead, 

dissolved

<5

<5

<.5

<.5

<5

<5

Manca- «. « ,. Sediment. ia»6» Man z Zi Sediment r^v" ,\ 

nese, " . ,. . . aediment. ,. . suspenoeo 

total nese> total dissolved SUSnended discharge, (percent 

. _ ..-..M dissolved recoverable (HS/L) , n\ suspended «. «, » recoveraoie * n \ / n \ (mc/L>i >. ..^ nnertnan

(MB/L) ^B/L> ^E/L> <ton/d> 0.062mm)

210 210 <10 <20 2 .29 79

231 170 <40 <20 8 10 78

273 61 E29 <20 62 39 71

131 97 <40 <20 11 3.4 68

93 41 <40 <20 24 16 57

110 80 <40 <1 4 .51 74

20 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
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

12323800-CLARK FORK NEAR GALEN, MONT.

Date

NOV 1998

17...

FEB 1999

22...

APR

27...

MAY

11...

27...

JUN

10...

22...

AUG

13...

Streamflow, Specific pH, Temper- Hardness, Calcium 

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

llme taneous onsite (standard water (mg/Las aissoivea 

(ft3/*) friS/cm) units) ("C) CaCOj) C mE'L>

1355

1420

1520

1040

1345

1155

1415

1145

124 460 8.8 4.0 190 55

113 517 8.7 4.5 230 66

158 398 8.7 12.0 170 48

183 401 8.5 8.0 160 48

499 229 8.4 12.0 94 28

435 286 8.8 9.0 120 34

522 197 8.8 12.5 81 24

91 373 8.8 15.0 160 48

Magnesium, 

dissolved 

(mg/L)

13

15

11

11

5.9

7.3

5.1

10

Arsenic, 

total 

recoverable

frig/L)

12

9

18

17

31

22

17

20

Date

NOV 1998

17..

FEB 1999

22...

APR

27..

MAY

11..

27..

JUN

10..

22..

AUG

13...

Arsenic, 

dissolved

fg/L)

9

7

15

17

17

17

14

19

Cadminm, Cadmium, C°PPfr' Copper, \n. a: total . . * . total . . i I total 

recoverable dissolved recoverable dissolved recoverable 

frig/L) "*" ' frig/L) iMi'^J frig/L)

<1 <1 5 3 110

<1 <.l 12 5 140

<1 .1 15 5 296

<1 <.l 15 5 294

<1 <.l 71 7 1,480

<1 <1 17 6 293

<1 <.l 19 5 355

<1 <1 12 3 190

Iron, 

dissolved

dg/L)

<10

<10

E8

12

25

13

16

14

Lead, 

total 

recoverable

fg/L)

<1

<1

2

2

9

2

2

1

Date

NOV 1998

17...

FEB 1999

22...

APR

27...

MAY

11 ..

27...

JUN

10...

22...

AUG

13...

Lead, 

dissolved

frig/L)

<5

<5

<.5

<5

<5

<5

<.5

<.5

Maesf Manga- Zinc, Zinc, Sediment 

t 4 i nese, total dissolved \ 

« £H,. dissolved recoverable fr.g/L) suspended

Tg/L) fr'8/L) fcg/L)

120 89 <10 <20 3

200 150 20 <20 5

179 89 <40 <20 10

139 82 E25 <20 10

303 51 56 <20 77

130 75 <40 <20 18

116 40 <40 <20 16

143 54 <40 2 8

Sediment 

discharge, 

suspended 

(ton/d)

1.0

1.5

4.3

49

104

21

23

2.0

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

86

84

83

84

73

50

66

83

TABLE 4 21
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

12324200--CLARK FORK AT DEER LODGE, MONT.

Date

NOV 1998

17...

FEE 1999

22...

APR

27...

MAY

11...

27...

JUN

10...

22...

AUG

13...

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

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

lime taneous onsite (standard water (mg/Las ,,n\ 

(frVs) OiS/cm) units) (°C) CaCO3) (mW

1505 286 473 8.4 4.0 210 60

1540 225 502 8.6 4.0 230 67

1625 250 454 8.9 12.5 200 57

1200 281 460 8.6 8.5 200 57

1230 506 286 8.0 14.0 120 34

0910 500 341 8.2 9.0 140 42

1600 684 234 8.3 14.5 95 28

1340 132 467 8.6 170 200 59

Magnesium, 

dissolved 

(mg/L)

14

15

13

13

7.4

9.2

6.0

13

Arsenic, 

total 

recoverable

12

9

14

14

56

27

20

20

Date

NOV 1998

17...

FEE 1999

22...

APR

27...

MAY

11...

27...

JUN

10..

22..

AUG

13...

Arsenic, C"* f"1 ' Cadmium, <*** Copper, J ' 

dtSg/L)d recoverable *£$? recoverable '"j^f recoverable

9 <1 <.l 16 4 280

7 <1 .1 16 5 220

12 <1 <l 20 7 339

13 <1 <.l 24 6 408

19 I <1 260 11 3,750

17 <1 <.l 59 10 904

15 <1 <.l 70 10 927

18 <1 <.l 32 7 377

Iron, 

dissolved

<10

<10

<10

<10

23

16

18

E7

Lead, 

total 

recoverable 

(Hg/L)

2

2

2

3

31

8

7

4

Date

NOV 1998

17...

FEE 1999

22...

APR

27...

MAY

11...

27...

JUN

10...

22..

AUG

13...

Lead, Mna«3T ManSa- Zinc; ..Zin.c' . Sediment, 

dissolved total .. nes.e> H hi dissolved suspended 

(Hg/L) recoverable dissolved recoverable (Mg/L) (^

(no/I» (Hg/L) Oig/L) & ' lMg/L|

<.5 70 24 20 <20 15

<.5 91 51 30 <10 15

<5 77 25 E27 <20 14

<5 97 33 E36 E8 18

<5 582 47 188 <20 219

<5 159 23 E38 <20 48

<.5 132 16 51 <20 53

<.5 147 22 E38 5 25

Sediment 

discharge, 

suspended 

(ton/d)

12

9.1

94

14

299

65

98

8.9

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

60

72

69

73

67

59

48

90

22 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
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON, MONT.

Date

NOV 1998

17..

APR 1999

27...

MAY

24..

JUN

04...

23...

AUG

10...

Streamflow, 

T. instanTime taneous 

(ft3/s)

1610 83

1725 208

1820 455

1130 852

1730 208

1045 54

Specific pH, Temper- Hardness, ,. . 

conductance, onsite ature, total .. ., .' 

onsite (standard water (mg/L as ! , 

(MS/cm) units) (°C) CaCOj) I"1 *"-'

277 8.4 3.5 130 36

206 8.4 10.5 91 26

168 8.2 16.5 75 22

186 8.0 9.5 82 24

238 8.3 18.0 110 31

289 8.5 16.0 140 39

Magnesium, 

dissolved 

(mg/L)

8.5

6.2

5.0

5.5

7.2

9.0

Arsenic, 

total 

recoverable

5

5

8

9

5

6

Date

NOV 1998

17...

APR 1999

27...

MAY

24...

JUN

04..

23..

AUG

10...

Arsenic, Cad"»p 

"f able

3 <1

5 <1

5 <1

6 <\

6 <\

6 <1

Cadmium, C°WT< Copper, j£J

d;ss°!-d recoTrable "f recoverable 

WL} CuyL) t"^ ^,,/L)

<1 <1 1 60

<.l 3 1 367

<.l 5 2 1,290

<.l 6 3 1,950

<1 2 1 120

<.l 2 <l 92

Iron, 

dissolved 

(ng/L)

<10

56

41

90

14

13

Lead, 

total 

recoverable

fcg/L)

<1

<|

3

4

<1

<1

Date

NOV 1998

17...

APR 1999

27...

MAY

24..

JUN

04..

23...

AUG

10...

MangaLead, nese, 

dissolved total 

(ng/L) recoverable 

fcg/L)

<.5 <10

<.5 27

<.5 78

<.5 104

<.5 16

<.5 21

Manga- Zinc, Zinc, ,. 

nese, total dissolved . 1 

dissolved recoverable frig/L) "(niE/L)

5 <|0 <20 3

7 <40 <20 14

8 <40 <20 84

10 <40 <20 120

10 <40 <20 7

12 <40 <1 4

Sediment 

discharge, 

suspended 

(ton/d)

.67

7.9

103

276

3.9

.58

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

83

85

56

51

91

87

TABLE 4 23
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

12324680--CLARK FORK AT GOLDCREEK, MONT.

Date

NOV 1998

18...

FEE 1999

23...

APR

28...

MAY

11...

27...

JUN

07...

22...

AUG

13...

Time

0810

0830

0820

1300

1105

1455

1800

1430

Streamflow. Specific 

install- conductance, 

taneous onsite 

(ft3/s) (nS/cm)

466 436

350 458

575 369

620 357

1,180 237

1,720 251

1,080 266

248 406

pH, Temperensile ature, 

(standard water 

units) (°C)

8.2 2.5

8.5 1.5

8.2 8.5

8.6 9.5

8.1 12.0

8.2 12.5

8.4 16.0

8.7 18.5

Hardness, Calciulll> 

. to'al dissolved ago? <m^>

190 55

200 59

160 47

150 44

100 29

110 31

110 33

170 51

Magnesium, 

dissolved 

(mg/L)

12

13

11

10

6.4

6.7

7.2

11

Arsenic, 

total 

recoverable

(Mg/L)

10

8

12

10

25

18

16

12

Date

NOV 1998

18...

FEE 1999

23...

APR

28...

MAY

ll._

27...

JUN

07..

22...

AUG

13 .

Arsenic, 

dissolved

(HE/L)

7

6

7

8

13

11

12

11

Cadmium, ^ 

recoverable «? frig/D <^L>

<i <i

<i <.i

<i .1

<i <.i

<i <.i

<i <.i

<i <.i

<i <i

Copper, 

total 

recoverable 

(Hg/L)

17

16

35

19

100

48

47

16

C°PPer' lotal' 

issolve recoverable

V&V (ng/L)

3 270

4 230

4 725

4 426

6 2,240

8 1,140

8 725

6 209

Iron, 

dissolved

(Hg/L)

<10

<10

13

E8

33

29

15

E5

Lead, 

total 

recoverable

(Hg/L)

2

1

4

2

15

7

5

1

Date

NOV 1998

18...

FEB 1999

23...

APR

28...

MAY

11...

27...

JUN

07..

22...

AUG

13...

Lead, 

dissolved

(Hg/L)

<.5

<5

<.5

<.5

<.5

<5

<.5

<.5

Mn"eT

reco'ver'able di,SS«^d 

(Hg/L) ^g/L)

70 16

70 33

111 21

68 12

299 12

129 12

109 10

78 10

Zinc, 

total 

recoverable

(Hg/L)

20

20

<40

E23

102

44

48

E21

.Zinc' Sediment, dissolved . . 

. n . suspended

^g/L> (mg/L)

<20 12

E13 11

<20 38

<20 22

<20 126

<20 72

<20 41

2 11

Sediment 

discharge, 

suspended 

(ton/d)

15

10

59

37

401

334

120

74

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

81

83

83

81

75

51

60

86

24 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
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

12331500-FLINT CREEK NEAR DRUMMOND, MONT.

Date

NOV 1998

18...

FEB 1999

23...

APR

28...

MAY

11-

27...

JUN

07...

23...

AUG

10...

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

taneous onsite (standard water 

(ft^s) (nS/cm) units) (°C)

0915 174 324 8.4 3.0

0940 E120 307 8.6 1.5

0930 E240 214 8.3 7.0

1405 156 251 8.7 10.0

0955 253 146 8.3 8.0

1540 324 206 8.2 11.0

1620 172 265 8.6 17.0

1610 35 434 8.8 20.5

Hardness, 

total 

(mg/L as 

CaC03)

150

140

96

110

65

96

120

200

Calcium, 

dissolved 

(mg/L)

39

39

25

30

18

26

33

55

Magnesium, 

dissolved 

(mg/L)

12

12

8.0

9.2

4.8

7.3

9.1

16

Arsenic, 

total 

recoverable

(Hg/L)

8

8

51

13

19

20

13

12

Date

NOV 1998

18-

FEB 1999

23...

APR

28...

MAY

11...

27...

JUN

07...

23...

AUG

10...

Arsenic, ^"al""' Cadmium, C°PPJrd}s!i'!v?d recoverable ^nf recoverable 

(Hg/L) IMg/M (ng/L)

5 <1 <1 1

6 <\ <.\ 2

9 <1 .1 14

7 <1 <.l 6

7 <1 <.l 7

7 <1 <.l 5

8 <l <1 4

11 <1 <1 3

Copper, 

dissolved

1

<1

3

2

2

2

2

1

Iron, 

total 

recoverable

(Hg/L)

160

180

1,970

565

803

685

297

133

Iron, 

dissolved

(HB/L)

<10

E8

91

51

52

27

42

E10

Lead, 

total 

recoverable

2

2

32

8

14

14

5

1

Date

NOV 1998

18...

FEB 1999

23...

APR

28...

MAY

11

27..

JUN

07..

23...

AUG

10...

Lead, Mnensl,a" Mm^ fnc.' 

W recTUe -

<.5 60 20 <10

<.5 60 15 <10

.7 405 29 74

.6 124 23 E25

.5 192 19 40

.5 210 19 E34

<.5 104 28 <40

<.5 88 53 <40

Zinc, 

dissolved

<20

<20

<20

<20

<20

<20

E8

4

Sediment, 

suspended 

(mg/L)

8

8

133

29

51

55

19

7

Sediment 

discharge, 

suspended 

(ton/d)

3.8

2.6

86

12

35

48

&£

.66

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

86

90

86

90

80

59

74

89

TABLE 4 25
Table 4. Water-quality data for the upper Clark Fork basin. Montana, October 1998 through September 1999 (Continued)

12331800--CLARK FORK NEAR DRUMMOND, MONT.

Date

NOV 1998

18...

FEE 1999

24...

APR

28...

MAY

11...

27...

JUN

07...

23...

AUG

13...

Time

1020

0945

1030

1505

0810

1415

1500

1615

Streamflow, Specific pH, Temperinstan- conductance, onsite a hi re, 

taneous onsite (standard water 

(ft3/*) (uS/cm) units) (°C)

755 454 8.3 4.5

542 463 8.4 3.5

883 363 8.2 9.5

842 384 8.5 11.0

1,340 281 8.1 12.5

2,330 276 8.2 11.5

1,390 320 8.4 17.0

412 513 8.5 18.0

Hardness, Calcium,

(mg'/L'as * *? 

CaC03) C"^)

200 56

210 61

160 45

170 49

120 34

120 35

140 41

240 67

Magnesium, 

dissolved 

(mg/L)

14

15

11

12

8.1

8.0

94

17

Arsenic, 

total 

recoverable

10

8

20

11

28

22

15

13

Date

NOV 1998

18...

FEE 1999

24...

APR

28...

MAY

11...

27...

JUN

07...

23...

AUG

13...

Arsenic, 

dissolved

7

7

8

10

13

11

14

13

Cadmium. Cadmium Copper, 

recoverable I^E/LI recoverable

<1 <l 13

<l <1 12

<1 <1 34

<l <1 23

<1 <1 100

<1 <.l 71

<1 <1 37

<1 <1 19

Copper, E£f

dissolved L, 

, «v recoverable

3 220

4 200

4 1,040

5 515

6 2,360

9 1,790

8 695

5 373

Iron, 

dissolved

<10

E5

20

E8

30

26

11

<10

Lead, 

total 

recoverable

2

2

11

3

18

13

4

3

Date

NOV 1998

18...

FEE 1999

24..

APR

28...

MAY

11...

27...

JUN

07...

23...

AUG

13...

Lead, 

dissolved

<.5

<.5

<5

<.5

<5

<5

<.5

<5

MnaeT Mane"- Zinc' 

T^r total  

ncse' total reC(°^a>bl£

70 10 20

50 20 20

172 13 43

82 13 E25

337 10 142

219 12 96

96 11 44

128 8 E34

dissolved Sediment,

<20 11

<20 13

<20 63

<20 29

<20 143

E8 122

<20 38

3 25

Sediment 

discharge, 

suspended 

(ton/d)

22

19

150

66

517

768

143

28

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

87

73

80

78

82

56

63

89

26 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
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

12334510-ROCK CREEK NEAR CLINTON, MONT.

Date

NOV 1998

18..

APR 1999

28...

MAY

26...

JUN

09...

23...

AUG

13...

Streamflow, Specific pH, Temper- Hardness, falc' 

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

"me taneous onsite (standard water (mg/L as «"*»"yeu 

(ft3/s) (MS/cm) units) (°C) CaCOj) (mg/L)

1145 252 142 8.5 4.0 63 16

1245 1,000 85 8.2 6.0 37 9.4

1045 3,040 53 7.8 9.0 23 6.0

1320 2,190 68 7.8 7.0 30 7.8

1310 1,730 81 8.0 12.0 37 97

1720 358 133 8.8 15.5 61 16

Magnesium, 

dissolved 

(ms/L)

5.6

3.3

1.9

2.5

3.0

5.1

Arsenic, 

total 

recoverable

(MS/L)

<1

<1

1

<1

<1

<1

Date

NOV 1998

18...

APR 1999

28...

MAY

26...

JUN

09...

23..

AUG

13..

Arsenic, C»d um' Cadmium, C°P Copper, J '

*"< **d recoverable "*d recoverable djsso'vf recoverable 

<W (MB/L) (M^L) (ME/L) <««-) <Mg/L)

<1 <1 <.l <1 <1 30

<1 <1 <.l 3 2 389

<l <l <1 3 <1 1,340

<1 <1 <.l 2 1 189

<1 <1 <1 1 <1 147

<l <1 <.l <l <1 35

Iron, 

dissolved 

(MB/D

E6

94

74

48

33

11

Lead, 

total 

recoverable

(MS/L)

<1

<1

1

<1

<1

<1

Date

NOV 1998

18...

APR 1999

28..

MAY

26..

JUN

09..

23..

AUG

13...

"S" Jvlble *g- reC5)b'e ^S? (ME/L) IME/M (MS/M

<5 <IO <4 <10 <20 2

<5 16 E2 <40 <20 20

<.5 64 4 <40 <20 205

<.5 9 E3 <40 E7 14

<5 7 E3 <40 <20 9

<.5 3 1 <40 2 2

Sediment 

discharge, 

suspended 

(ton/d)

14

54

1,680

83

42

1 9

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

62

71

35

55

69

70

TABLE 4 27
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

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

Date

NOV 1998

18...

FEE 1999

24...

APR

28...

MAY

12...

'25...

'26..

26

'28..

JUN

'02..

'04..

'07..

07

'09..

23...

AUG

10 .

'15

'19..

"22..

'25...

Time

1350

1120

1445

0905

1025

0900

1250

0825

1100

1020

0900

1210

0905

1120

1330

1220

1030

0800

0945

Streamflow, 

instantaneous 

(ft3/s)

1,070

820

2,100

1,780

3,360

3,940

4,030

4,330

4,630

6,410

5,360

5,310

4,560

3,380

648

831

730

639

596

Specific 

conductance, 

onsite 

(nS/cm)

373

380

227

268

160

143

141

138

163

153

164

165

184

192

329

346

360

360

360

pH, 

onsite 

(standard 

units)

86

8.6

8.2

8.4

79

7.8

8.1

7.8

8.1

7.7

7.8

8.1

8.0

8.3

8.8

8.5

8.4

8.3

8.4

Temperature, 

water <°C)

5.0

4.0

8.0

8.5

13.0

12.0

12.0

11.0

11.0

10.0

9.0

9.5

8.0

13.0

19.5

15.0

18.0

15.0

15.0

Hardness, 

total 

(mg/Las 

CaC03)

160

170

100

120

68

62

59

60

70

65

69

70

82

84

140

160

160

160

160

Calcium, 

dissolved 

(mg/L)

46

48

28

32

19

17

16

17

20

19

20

20

23

24

40

44

45

45

45

Magnesium, 

dissolved 

(mg/L)

12

12

7.6

8.6

4.9

4.5

4.3

4.4

5.0

4.5

4.9

5.0

5.9

60

11

12

12

12

12

Arsenic, 

total 

recoverable

<Mg/L)

7

6

8

6

10

10

11

9

11

16

10

12

9

7

6

8

8

8

7

28 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
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued) 

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

Date

NOV 1998

18...

FEB 1999

24...

APR

28...

MAY

12...

'25...

'26...

26...

'28...

JUN

'02...

'04...

'07...

07..

'09...

23...

AUG

10...

'15...

'19...

'22...

'25...

Arsenic, 

dissolved

(Mg/L)

5

5

5

5

4

5

5

5

6

6

6

6

6

5

6

7

8

7

8

Cadmium, Cadmiunl, Copper,

recoverable *~*tf ble

(Mg/L) (M8/L) (Mg/L)

<1 <1 8

<1 <.l 7

<1 <1 22

<1 <1 13

<1 <1 57

<1 <.l 61

<1 <1 60

<1 <.l 46

<1 <.l 59

<1 <1 92

<1 <1 47

<1 <.l 40

<1 <.l 40

<1 <.l 19

<1 <1 6

<1 <1 12

<.l <.l 12

<1 <1 9

<.l <.l 7

Copper, 

dissolved

(Mg/L)

3

3

4

3

4

5

4

5

6

9

7

6

6

4

3

3

3

3

3

Iron, 

total 

recoverable

(Mg/L)

150

100

773

313

2,010

2,680

2,010

1,720

1,540

3,450

1,420

1,130

1,060

389

53

189

150

127

84

Iron, 

dissolved

(Mg/L)

<10

<10

49

16

32

45

51

46

32

49

31

37

24

21

<10

<10

<10

<10

<10

Lead, 

total 

recoverable

(Mg/L)

1

<1

5

2

9

12

10

8

9

17

8

7

13

2

<1

1

1

E.8

E.5

TABLE 4 29
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued) 

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

Date

NOV 1998

18..

FEE 1999

24...

APR

28...

MAY

12...

'25...

'26...

26...

'28...

JUN

'02...

'04...

'07...

07...

'09...

23...

AUG

10...

'15...

'19...

'22...

'25...

Lead, 

dissolved 

(HB/L)

<.5

<.5

<5

<.5

<.5

<5

<5

<.5

<5

<.5

<.5

<.5

<.5

<5

<.5

<5

<.5

<.5

<5

Manganese, 

total 

recoverable 

(Hg/L)

40

20

90

46

194

261

224

172

157

326

144

129

104

48

19

56

47

40

28

Manganese, 

dissolved 

(Hg/L)

E3

7

9

5

1

2

14

3

3

2

3

9

4

6

4

<l

1

<1

<1

Zinc, 

total 

recoverable 

(HB/L)

10

10

E38

<40

87

113

264

73

81

143

64

68

60

<40

<40

<31

E19

<31

<31

Zinc, 

dissolved 

(Hg/L)

<20

<20

<20

<20

4

4

<20

3

5

6

6

<20

5

<20

2

2

2

3

2

Sediment, 

suspended 

(mg/L)

9

7

52

18

133

220

196

142

101

320

105

82

78

24

5

12

10

10

6

Sediment 

discharge, 

suspended 

(ton/d)

26

15

295

87

1,210

2,340

2,130

1,660

1,260

5,540

1,520

1,180

960

219

8.7

27

20

17

9.7

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

93

84

66

84

52

-

_.

-

-

62

65

70

__

__

__

-

30 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
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

I2340000--BLACKFOOT RIVER NEAR BONNER, MONT.

Date

NOV 1998

18..

APR 1999

29...

MAY

26...

JUN

09...

23...

AUG

15...

'15...

'19...

'22...

'25...

Time

1600

0810

1435

0920

0745

1010

1340

1130

0915

1125

Streamflow, Specific 

instan- conductance, 

taneous onsite

(ffVs) friS/cm)

634 276

3,900 163

8,990 139

5,800 171

5,310 160

990 255

990 249

862 259

794 260

750 260

pH, Temper- Hardness, 

onsite ature, total 

(standard water (mg/L as

units) (°C) CaCOj)

8.7 4.5 130

8.3 6.0 80

8.5 10.0 70

8.2 8.5 86

8.2 11.0 81

8.7 13.5 130

8.6 15.0 130

8.5 18.0 130

8.5 16.0 130

8.5 16.0 130

Calcium, 

dissolved

(mg/L)

33

21

18

22

21

33

32

33

33

33

Magnesium, 

dissolved

(mg/L)

12

7.0

5.7

7.3

6.9

11

12

12

12

12

Arsenic, 

total 

recoverable

frig/L)

<1

<1

3

1

<1

1

1

1

1

2

Date

NOV 1998

18...

APR 1999

29...

MAY

26..

JUN

09..

23..

AUG

15..

'15..

'19..

'22..

'25...

Arsenic, 

dissolved

frig/L)

<1

<1

<1

1

1

<1

<1

1

<]

<1

Ca?.tr cdfmiumrecoverable . **

frtg/L) VSM

<1 .1

<1 <1

<1 <1

<1 <1

<1 <1

<1 <1

<.l <.l

<1 <.l

<] <i

<.l <1

czr c°pp"'

recoverable "?"

frig/L) WV

<1 <1

2 <1

13 2

2 1

3 2

<1 <1

<1 <1

<1 <1

<1 <1

<1 <1

Iron, 

total 

recoverable

(HE/L)

60

338

2,410

416

307

45

47

32

34

25

Iron, 

dissolved

(|Jg/L)

<10

35

47

18

14

E6

<10

<10

<10

<10

Lead, 

total 

recoverable

(jig/L)

<1

<1

4

<1

<1

<1

1

<]

<]

<1

Date

NOV 1998

18...

APR 1999

29..

MAY

26..

JUN

09

23..

AUG

15..

'15...

'19...

'22...

'25...

Lead, 

dissolved 

(ng/L)

<5

<5

<5

<.5

<5

<5

<5

<5

<5

<5

total di"85]'' d 

recoverable (UE/L)

<10 E2

31 E2

165 5

30 3

20 E2

7 1

7 <1

6 <1

7 <1

5 <1

Zinc, Zinc, 

total dissolved 

recoverable (jag/L)

<10 <20

<40 <20

<40 <20

<40 <20

<40 <20

<40 <1

<31 <1

<31 <1

<31 <1

<31 <1

Sediment, 

suspended

4

25

265

36

28

4

2

3

3

2

Sediment 

discharge, 

suspended 

(ton/d)

6.8

263

6,430

564

401

11

5.3

7.0

6.4

4.1

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

82

85

77

85

76

80

-

TABLE 4 31
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

12340500-CLARK FORK ABOVE M1SSOULA, MONT.

Date

NOV 1998

19..

FEE 1999

24..

APR

29...

MAY

11...

'25...

'26...

26...

'28...

JUN

'02...

'04...

'07...

09...

'09...

23...

AUG

15...

'15...

'19...

'22...

'24...

'25...

'27...

Time

0900

1350

0940

1730

1155

1115

1610

1135

1300

1245

1130

1055

1200

0915

1150

1515

1245

1045

1110

1240

1120

Streamflow, 

instantaneous 

(ft3/*)

1,700

1,090

5,880

4,710

11,000

12,900

13,400

12,600

11,200

14,200

12,400

10,300

10,300

8,580

,870

,830

,610

,450

,460

920

1,330

Specific 

conductance, onsite

(jaS/cm)

330

326

188

212

157

146

142

146

164

156

164

177

177

173

293

293

303

300

299

306

299

pH,

onsite 

(standard 

units)

8.4

8.6

8.2

8.5

8.0

8.1

8.1

8.0

8.1

7.7

7.8

8.3

8.1

8.2

8.7

8.4

8.4

8.5

8.4

8.2

8.6

Temperature, 

water <°C)

4.0

4.0

6.5

9.0

13.0

12.0

12.0

12.0

11.0

11.0

10.0

8.5

12.0

12.0

14.5

15.0

20.0

18.0

17.0

18.0

19.0

Hardness, 

total 

(mg/L as 

CaC03)

150

150

88

99

75

70

68

70

76

72

76

83

84

81

140

140

140

140

140

140

140

Calcium, 

dissolved 

(mg/L)

41

41

23

26

20

19

18

19

21

20

20

22

23

22

36

37

38

37

37

38

37

Magnesium, 

dissolved 

(mg/L)

12

12

7.2

8.1

6.0

5.5

5.4

5.6

6.1

5.6

6.0

6.6

6.7

6.5

11

12

12

12

12

12

12

Arsenic, 

total 

recoverable 

(Mg/M

5

4

4

2

4

5

5

5

5

8

5

5

4

3

4

5

5

5

5

7

5

32 Water-quality, bed-sediment, and biological data (October 1998 through September 1999) and statistical summaries of data for streams in tbe 

Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

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

Date

NOV 1998

19...

FEE 1999

24...

APR

29...

MAY

11...

'25...

'26...

26...

'28...

JUN

'02...

'04...

'07...

09...

'09...

23...

AUG

15...

'15...

'19...

'22...

'24...

'25...

'27...

Arsenic, 

dissolved 

<Mg/L)

4

3

1

2

3

3

2

3

3

3

3

3

3

2

3

4

4

5

4

5

4

Cadmium, ~ . . Copper, total Ca dm,um, , £,

recoverable / "nT recoverable 

<Mg/L) <Mg/L' (ng/L)

<1 <.l 4

<1 <.l 4

<l .1 8

<1 <.l 6

<1 <l 19

<1 <1 20

<1 <.l 22

<1 <1 20

<1 <.l 32

<1 <l 50

<1 <1 25

<1 <.l 18

<1 <.l 32

<1 <.l 11

<1 <.l 7

<.l <1 5

<.l <1 6

<.l <1 6

<1 <.l 8

.4 <.l 25

<.l <1 3

Copper, 

dissolved 

<Mg/L)

2

2

3

2

3

2

2

3

3

5

4

4

4

3

3

2

2

2

1

2

1

Iron, 

total 

recoverable 

<Mg/L)

100

80

414

204

1,570

2,050

2,200

1,450

912

1,860

970

607

709

392

110

107

138

163

210

601

71

Iron, 

dissolved

<Mg/D

<10

E6

46

15

23

34

49

32

23

29

23

24

19

50

E7

<10

<10

<IO

E6

<IO

<IO

Lead, 

total 

recoverable 

<Mg/L)

<1

<1

2

<1

4

5

5

4

4

8

4

3

4

2

<]

<!

E.8

E.7

1

9

<1

TABLE 4 33
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1998 through September 1999 (Continued)

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

Date

NOV 1998

19...

FEE 1999

24...

APR

29...

MAY

11...

'25.,

'26..

26...

'28...

JUN

'02...

'04...

'07...

09...

'09...

23...

AUG

15...

'15...

'19...

'22...

'24...

'25...

'27...

MangaLead, nese, 

dissolved total 

(Hg/L) recoverable 

(Hg/L)

<5 30

<5 40

<.5 47

<5 26

<.5 126

<.5 153

<.5 176

<.5 110

<.5 84

<5 169

<.5 82

<.5 66

<.5 62

<.5 39

<.5 24

<.5 23

<.5 46

<.5 49

<.5 57

<5 156

<5 26

Manganese, 

dissolved 

(Mg/L)

13

36

12

13

1

2

15

3

4

1

3

9

4

11

11

<]

<1

1

6

1

<1

Zinc, 

total 

recoverable

(ug/L)

<10

<10

<40

<40

E28

E33

40

E30

42

82

E37

E22

E34

<40

<40

<31

<31

<31

<31

32

<31

Zinc, 

dissolved 

(Hg/L)

<20

E7

<20

<20

1

1

<20

1

2

4

3

<20

3

<20

1

1

<1

2

1

2

<1

Sediment, 

suspended 

(mg/L)

5

3

25

13

110

154

200

109

60

128

68

43

42

28

9

6

8

9

13

32

8

Sediment 

discharge, 

suspended 

(ton/d)

23

8.8

397

165

3,270

5,360

7,240

3,710

1,810

4,910

2,280

1,200

1,170

649

45

30

35

35

51

79

29

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

95

95

92

92

-

85

-

-

83

_

89

95

__

__

__

-

'Supplemental samples collected to better define changes in trace-element concentrations and transport during extended high flows, and during the lowering of Milltown 

Reservoir water levels for dam maintenance.

34 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
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana. October 1998 through September 1999 

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

Day

,

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ffVs)

225

240

252

258

257

272

269

264

261

272

289

272

281

282

288

283

274

272

269

265

265

265

260

252

255

258

257

257

254

251

249

8,168

263

289

225

Suspended sediment

Mean 

concentration 

<mg/L)

October

20

25

29

29

27

36

21

21

21

22

22

22

22

21

20

17

15

14

14

15

18

19

18

16

13

11

11

11

14

11

11

_

19

36

11

Discharge 

(ton/d)

12

16

20

20

19

26

15

15

15

16

17

16

17

16

16

13

11

10

10

11

13

14

13

11

9.0

7.7

7.6

7.6

9.6

7.5

7.4

418.4

13

26

7.4

Mean 

streamflow 

(frVs)

248

248

253

255

258

273

270

277

291

304

290

297

300

321

313

293

286

300

300

291

295

315

302

300

290

276

254

251

257

253

...

8,461

282

321

248

Suspended sediment

Mean 

concentration 

< g/L)

1998

November

II

11

II

11

13

16

17

18

18

19

20

20

23

25

25

20

16

16

16

16

16

16

17

16

16

15

15

15

16

16

_

17

25

11

Discharge 

(ton/d)

7.4

7.4

7.5

7.6

9.1

12

12

13

14

16

16

16

19

22

21

16

12

13

13

13

13

14

14

13

13

11

10

10

11

II

3870

13

22

74

Mean 

streamflow 

(fr'/s)

248

248

252

250

230

221

222

217

225

222

232

244

254

262

246

246

252

230

163

149

e)40

el 40

e!50

el 50

e)60

175

198

215

241

276

259

6,717

217

276

140

Suspended sediment

Mean 

concentration 

<mg/L)

December

16

17

19

21

21

21

20

20

20

20

20

20

20

20

20

20

20

19

19

20

22

22

21

19

17

16

17

23

30

30

30

_

21

30

16

Discharge 

(ton/d)

II

11

13

14

13

13

12

12

12

12

13

13

14

14

13

13

14

12

8.4

8.0

8.3

8.3

8.5

7.7

7.3

7.6

9 1

13

20

22

21

378.2

12

22

73

TABLE 5 35
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1998 through September 1999 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

IS

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/*)

260

259

e230

242

253

260

256

248

247

251

266

264

257

255

266

257

248

249

252

252

251

245

241

236

230

237

238

250

242

251

234

7,727

249

266

230

Suspended sediment

Mean 

concentration 

(mg/L)

January

30

30

31

33

37

39

38

35

30

25

21

20

19

19

19

20

20

20

20

19

18

17

16

17

24

36

35

30

26

23

21

25

39

16

Discharge 

(ton/d)

21

21

19

22

25

27

26

23

20

17

15

14

13

13

14

14

13

13

14

13

12

11

10

11

15

23

22

20

17

16

13

527

17

27

10

Mean 

streamflow 

(frVs)

e220

220

248

227

234

225

231

230

242

248

236

246

262

237

231

232

233

230

232

226

228

228

234

243

267

268

246

265

6,669

238

268

220

Suspended sediment

Mean 

concentration 

(mg/L)

1999

February

20

20

28

23

21

23

28

31

29

26

25

25

25

25

25

25

24

22

20

18

16

17

19

24

24

22

23

28

-

_

23

31

16

Discharge 

(ton/d)

12

12

19

14

13

14

17

19

19

17

16

17

18

16

16

16

15

14

13

11

98

10

12

16

17

16

15

20

423.8

15

20

9.8

Mean 

streamflow 

(tf/s)

280

241

227

206

206

216

213

210

217

221

224

221

226

239

247

250

236

234

244

248

250

271

286

290

305

305

298

280

281

274

271

7,717

249

305

206

Suspended sediment

Mean 

concentration 

(mg/L)

March

62

30

18

20

21

24

22

26

23

24

29

21

24

26

33

34

24

31

32

40

40

54

55

52

69

59

42

32

34

36

34

_

35

69

18

Discharge 

(ton/d)

47

20

11

11

12

14

13

15

13

14

18

13

15

17

22

23

15

20

21

27

27

40

42

41

57

49

34

24

26

27

25

753

24

57

11

36 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
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1998 through September 1999 

(Continued)

Day

, '

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/*;)

249

238

246

243

238

232

226

226

223

219

218

217

214

210

212

212

214

215

219

220

245

246

244

240

237

237

249

278

281

276

7,024

234

281

210

Suspended sediment

Mean 

concentration 

(mg/L)

April

25

27

27

24

23

24

22

21

22

19

20

25

19

18

20

20

22

17

16

18

23

21

15

16

12

11

13

29

20

22

...

_

20

29

11

Discharge 

(ton/d)

17

17

18

16

15

15

13

13

13

11

12

15

11

10

1)

11

13

9.9

9.5

11

15

14

9.9

10

7.7

7.0

8.7

22

15

16

386.7

13

22

7.0

Mean 

streamflow 

(ft3/s)

273

280

292

303

289

274

266

258

274

287

280

265

258

245

241

245

238

230

253

262

278

324

363

333

352

408

483

488

547

733

690

10,312

333

733

230

Suspended sediment

Mean 

concentration 

(mg/L)

1999

May

22

18

22

39

23

20

22

18

18

18

18

16

16

14

16

17

16

16

24

27

31

70

90

70

92

135

205

150

160

230

135

57

230

14

Discharge 

(ton/d)

16

14

17

32

18

15

16

13

13

14

14

11

11

9.3

10

11

10

9.9

16

19

23

61

88

63

87

149

267

198

236

455

252

2,1682

70

455

9.3

Mean 

streamflow 

(ft3/s)

606

620

681

796

773

703

655

614

585

491

429

390

376

390

444

525

641

697

738

725

649

660

618

540

508

492

437

396

360

346

...

16,885

563

796

346

Suspended sediment

Mean 

concentration 

(mg/L)

June

85

90

102

112

90

80

75

61

50

46

37

34

34

39

61

79

97

95

94

80

58

51

46

39

36

34

26

18

12

II

...

...

59

112

11

Discharge 

(ton/d)

139

151

188

241

188

152

133

101

79

61

43

36

35

41

73

112

168

179

187

157

102

91

77

57

49

45

31

19

12

10

2,957

99

241

10

TABLE 5 37
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1998 through September 1999 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/*)

351

327

307

288

274

247

228

217

207

192

181

173

156

143

124

121

121

121

110

103

104

95

88

78

78

74

67

63

63

63

59

4,823

156

351

59

Suspended sediment

Mean 

concentration 

(mg/L)

July

11

10

9

7

5

5

6

6

5

5

5

6

6

6

5

4

3

4

4

5

6

5

4

4

3

3

3

4

4

3

4

5

11

3

Discharge 

(ton/d)

10

8.8

7.5

5.4

3.7

33

3.7

3.5

2.8

2.6

2.4

2.8

2.5

2.3

1.7

1 3

.98

1.3

1.2

1.4

1.7

1.3

.95

.84

,63

.60

.54

.68

.68

.51

.64

78.25

2.5

10

.51

Mean 

streamflow 

(ft3*)

1999

52

57

62

68

97

81

82

78

74

75

80

113

126

116

111

110

107

101

96

91

91

99

96

97

102

101

95

100

117

107

112

2,894

934

126

52

Suspended sediment

Mean 

concentration 

(mg/L)

August

7

16

18

21

49

9

8

7

6

5

7

19

23

14

13

13

13

12

12

11

10

10

9

9

7

7

7

9

10

8

8

12

49

5

Discharge 

(ton/d)

.98

2.5

3.0

3.9

13

2.0

1.8

1.5

1.2

1.0

1.5

5.8

7.8

4.4

3.9

3.9

3.8

3.3

3.1

2.7

2.5

2.7

2.3

2.4

1.9

1.9

1.8

2.4

3.2

2.3

2.4

96.88

3.1

13

.98

Mean 

streamflow 

(fr'/s)

118

122

135

153

166

161

157

160

165

165

150

153

160

157

157

150

150

156

163

162

154

151

144

132

145

150

154

160

166

163

4,579

153

166

118

Suspended sediment

Mean 

concentration 

(mg/L)

September

8

8

9

9

9

8

8

8

7

7

8

10

14

15

13

11

10

10

10

11

14

18

14

10

9

10

11

11

12

12

 -

10

18

7

Discharge 

(ton/d)

2.5

2.6

3.3

3.7

4.0

3.5

3.4

3.5

3.1

3.1

3.2

4.1

6.0

6.4

5.5

4.5

4.1

4.2

4.4

4.8

5.8

7.3

5.4

3.6

3.5

4.1

4.6

4.8

5.4

5.3

129.7

4.3

7.3

2.5

TOTAL FOR WATER YEAR 1999:

STREAMFLOW--91,976 ft3/s 

SEDIMENT DISCHARGE 8,704.13 tons

38 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
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1998 through 

September 1999

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

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/*)

955

982

1,030

1,050

1,060

1,050

1,060

1,050

1,050

1,090

1,150

1,130

1,110

1,110

1,130

1,150

1,120

1,100

1,090

1,090

1,100

1,090

1,080

1,080

1,060

1,050

1,040

1,030

1,010

1,010

1,000

33,107

1,068

1,150

955

Suspended sediment

Mean 

concentration 

(mg/L)

October

12

11

11

11

11

11

12

13

16

18

19

18

18

16

14

12

10

9

8

8

8

9

9

8

8

8

8

7

5

5

5

11

19

5

Discharge 

(ton/d)

31

29

31

31

31

31

34

37

45

53

59

55

54

48

43

37

30

27

24

24

24

26

26

23

23

23

22

19

14

14

14

982

32

59

14

Mean 

streamflow 

(ft3/*)

990

996

998

998

989

996

1,000

1,010

1,020

1,020

1,010

1,000

1,050

1,100

1,120

1,110

1,090

1,080

1,080

1,060

1,070

1,250

1,230

1,200

1,170

1,150

1,130

1,110

1,090

1,080

32,197

1,073

1,250

989

Suspended sediment

Mean 

concentration 

(mg/L)

1998

November

5

5

5

4

4

3

3

5

6

7

8

10

13

14

13

10

9

9

9

9

10

16

14

11

10

9

9

9

8

8

8

16

3

Discharge 

(ton/d)

13

13

13

11

11

8.1

8.1

14

17

19

22

27

37

42

39

30

26

26

26

26

29

54

46

36

32

28

27

27

24

23

754.2

25

54

8.1

Mean 

streamflow 

(fr'/s)

1,080

1,090

1,130

1,110

1,050

942

896

906

895

831

828

963

963

973

955

927

943

1,000

743

350

200

300

400

500

600

700

750

800

850

950

1,060

25,685

829

1,130

200

Suspended sediment

Mean 

concentration 

(mg/L)

December

7

8

8

7

5

4

5

5

5

5

7

8

8

8

8

8

8

8

8

9

10

12

14

10

8

56

52

50

50

37

27

...

15

56

4

Discharge 

(ton/d)

20

24

24

21

14

10

12

12

12

11

16

21

21

21

21

20

20

22

16

8.5

5.4

9.7

15

14

13

106

105

108

115

95

77

1,009.6

33

115

54

TABLE 6 39
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1998 through 

September 1999 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(frVs)

1,010

963

923

850

938

996

1,020

990

959

957

1,010

1,080

1,020

963

1,000

1,040

972

940

927

915

907

885

850

750

700

750

819

763

794

785

807

28,283

912

1,080

700

Suspended sediment

Mean 

concentration 

(mg/L)

January

10

8

8

8

8

8

9

10

15

21

26

28

26

24

22

20

19

17

15

14

12

11

10

9

8

7

8

10

12

12

13

14

28

7

Discharge 

(ton/d)

27

21

20

18

20

22

25

27

39

54

71

82

72

62

59

56

50

43

38

35

29

26

23

18

15

14

18

21

26

25

28

1,084

35

82

14

Mean 

streamflow 

(ft3/*)

800

807

806

817

796

794

818

817

812

750

700

707

725

807

813

771

794

789

776

775

760

762

798

811

949

1,010

930

911

...

22,605

807

1,010

700

Suspended sediment

Mean 

concentration 

(mg/L)

1999

February

12

10

10

9

9

9

9

9

9

8

8

7

6

5

5

6

8

8

6

5

5

5

5

5

22

25

20

28

...

...

_

10

28

5

Discharge 

(ton/d)

26

22

22

20

19

19

20

20

20

16

15

13

12

II

11

12

17

17

13

10

10

10

II

II

56

68

50

69

...

...

620

22

69

10

Mean 

streamflow

(frVs)

1,430

1,280

1,120

1,020

917

884

842

875

880

888

885

868

869

957

1,130

1,330

1,240

1,130

1,190

1,370

1,560

1,770

1,790

1,720

1,760

1,880

1,860

1,660

1,540

1,500

1,430

39,575

1,277

1,880

842

Suspended sediment

Mean 

concentration 

(mg/L)

March

207

75

30

19

13

10

10

11

12

II

10

10

12

18

30

50

37

23

30

46

67

100

84

62

60

76

60

33

30

24

21

_

41

207

10

Discharge 

(ton/d)

799

259

91

52

32

24

23

26

29

26

24

23

28

47

92

180

124

70

96

170

282

478

406

288

285

386

301

148

125

97

81

5,092

164

799

23

40 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
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1998 through 

September 1999 (Continued)

Day

,

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

M1N

Mean 

streamflow 

(frVs)

1,360

1,290

1,250

1,240

1,210

1,170

1,140

1,140

1,160

1,170

1,180

1,190

1,200

1,210

1,230

1,230

1,250

1,340

1,520

1,790

1,930

1,880

1,780

1,720

1,720

1,820

1,960

2,070

2,040

1,950

44,140

1,471

2,070

1,140

Suspended sediment

Mean 

concentration 

(mg/L)

April

20

17

17

17

14

12

10

II

11

10

9

8

10

12

II

12

16

18

34

56

58

43

35

28

27

31

45

57

50

34

24

58

8

Discharge 

(ton/d)

73

59

57

57

46

38

31

34

34

32

29

26

32

39

37

40

54

65

140

271

302

218

168

130

125

152

238

319

275

179

3,300

no

319

26

Mean 

streamflow 

(ft3/s)

1,890

1,940

1,990

1,990

1,920

1,830

1,800

1,820

1,830

1,840

1,820

1,790

1,770

1,710

1,610

1,560

1,570

1,590

1,780

1,980

2,120

2,380

2,610

2,900

3,430

4,130

4,540

4,440

4,610

5,390

5,160

77,740

2,508

5,390

1,560

Suspended sediment

Mean 

concentration 

(mg/L)

1999

May

33

32

32

30

28

22

21

18

19

18

18

19

18

13

II

10

II

II

16

26

39

47

55

81

116

178

148

107

no

186

138

_

52

186

10

Discharge 

(ton/d)

168

168

172

161

145

109

102

88

94

89

88

92

86

60

48

42

47

47

77

139

223

302

388

634

1,070

1,980

1,810

1,280

1,370

2,710

1,920

15,709

507

2,710

42

Mean 

streamflow

(ft3/!.)

4,570

4,630

5,050

6,340

6,440

5,930

5,310

4,810

4,510

4,020

3,530

3,210

3,070

3,180

3,420

3,750

4,240

4,260

4,170

4,020

3,740

3,520

3,390

3,070

2,960

2,870

2,630

2,430

2,210

2,110

117,390

3,913

6,440

2,110

Suspended sediment

Mean 

concentration 

(mg/L)

June

82

75

98

212

166

123

84

64

59

48

44

40

37

39

40

50

72

65

59

51

42

29

26

27

25

21

20

16

12

13

_

58

212

12

Discharge 

(ton/d)

1,010

938

1,340

3.630

2,890

1,970

1,200

831

718

521

419

347

307

335

369

506

824

748

664

554

424

276

238

224

200

163

142

105

72

74

-

22,039

735

3,630

72

TABLE 6 41
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1998 through 

September 1999 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/*)

2,130

2,100

2,020

1,950

1,880

1,790

1,710

1,620

1,550

1,480

1,410

1,340

1,280

1,230

1,190

1,150

1,130

1,120

1,100

1,070

1,060

1,050

1,010

963

945

903

859

813

766

728

674

40,021

1,291

2,130

674

Suspended sediment

Mean 

concentration 

<mg/L)

July

13

11

11

9

8

7

7

6

5

4

4

4

4

4

4

4

3

3

3

3

3

3

3

3

3

3

3

3

3

2

2

_

5

13

2

Discharge 

(ton/d)

75

62

60

47

41

34

32

26

21

16

15

14

14

13

13

12

9.2

9.1

8.9

8.7

8.6

8.5

8.2

7.8

7.7

7.3

7.0

6.6

6.2

3.9

3.6

606.3

20

75

3.6

Mean 

streamflow 

(ft3/*)

635

616

638

654

683

729

734

714

654

643

638

692

791

833

834

828

785

752

733

700

661

635

621

602

619

625

595

601

629

646

653

21,173

683

834

595

Suspended sediment

Mean 

concentration 

(mg/L)

1999

August

2

2

2

3

3

3

3

4

4

4

4

5

10

11

12

13

10

9

10

8

8

9

7

6

6

6

6

7

9

9

9

_

7

13

2

Discharge 

(ton/d)

3.4

3.3

3.4

5.3

5.5

5.9

5.9

7.7

7.1

6.9

6.9

9.3

21

25

27

29

21

18

20

15

14

15

12

98

10

10

9.6

11

15

16

16

385.0

12

29

33

Mean 

streamflow 

(ft3/*)

669

658

679

735

747

732

711

688

679

673

657

647

641

645

649

656

645

634

637

649

638

617

597

579

571

591

615

627

645

677

19,588

653

747

571

Suspended sediment

Mean 

concentration 

<mg/L)

September

9

10

10

10

10

9

8

7

7

7

6

6

6

6

6

6

6

5

5

5

5

5

5

5

5

5

5

5

5

5

_

6

10

5

Discharge 

(ton/d)

16

18

18

20

20

18

15

13

13

13

11

10

10

10

11

11

10

8.6

8.6

8.8

8.6

8.3

8.1

7.8

7.7

8.0

8.3

8.5

8.7

9.1

-

346.1

12

20

77

TOTAL FOR WATER YEAR 1999

STREAMFLOW-501,504 ft3/s 

SEDIMENT DISCHARGE-51,927.2 tons

42 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
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1998 through September 1999 

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

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(fr'/s)

1,460

1,500

1,540

1,570

1,600

1,580

1,570

1,560

1,560

1,600

1,690

1,710

1,670

1,680

1,670

1,680

1,680

1,670

1,640

1,620

1,610

1,610

1,600

1,610

1,600

1,590

1,580

1,580

1,570

1,560

1,560

49,720

1,604

1,710

1,460

Suspended sediment

Mean 

concentration 

(mg/L)

October

6

6

5

5

5

4

5

5

5

6

6

6

7

7

7

7

7

6

6

5

5

5

5

5

5

5

5

5

5

4

4

_

5

7

4

Discharge 

(ton/d)

24

24

21

21

22

17

21

21

21

26

27

28

32

32

32

32

32

27

27

22

22

22

22

22

22

21

21

21

21

17

17

737

24

32

17

Mean 

streamflow 

(ft3/*)

1,540

1,540

1,560

1,550

1,530

1,560

1,560

1,580

1,570

1,540

1,560

1,520

1,580

1,700

1,780

1,780

1,730

1,720

1,680

1,660

1,660

1,880

1,940

1,920

1,850

1,800

1,780

1,820

1,830

1,790

50,510

1,684

1,940

1,520

Suspended sediment

Mean 

concentration 

(mg/L)

1998

November

4

4

4

3

3

3

3

3

3

4

5

5

6

6

6

6

5

5

5

5

5

6

6

5

5

5

5

6

6

6

_

5

6

3

Discharge 

(ton/d)

17

17

17

13

12

13

13

13

13

17

21

21

26

28

29

29

23

23

23

22

22

30

31

26

25

24

24

29

30

29

660

22

31

12

Mean 

streamflow 

(fr'/s)

1,770

1,790

1,850

1,830

1,760

1,590

1,550

1,560

1,520

1,420

1,430

1,560

1,570

1,570

1,550

1,500

1,530

1,520

el, 050

e600

e500

e450

e550

e700

e900

el, 100

el,300

el, 400

el, 600

el, 700

el, 800

42,520

1,372

1,850

450

Suspended sediment

Mean 

concentration 

(mg/L)

December

5

5

5

4

4

5

5

5

4

4

5

6

7

6

6

5

5

4

4

4

4

3

3

3

4

7

10

9

8

6

6

_

5

10

3

Discharge 

(ton/d)

24

24

25

20

19

21

21

21

16

15

19

25

30

25

25

20

21

16

11

6.5

5.4

3.6

4.5

5.7

9.7

21

35

34

35

28

29

6154

20

35

36

TABLE 7 43
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula. Montana. October 1998 through September 1999 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/*)

el,900

el,800

1,610

1,520

1,570

1,630

1,670

1,610

1,590

1,570

1,690

1,680

1,650

1,620

1,640

1,680

1,660

1,600

1,550

1,540

1,520

1,470

1,460

1,350

1,180

1,190

1,330

1,450

1,430

1,550

1,430

48,140

1,553

1,900

1,180

Suspended sediment

Mean 

concentration 

(mg/L)

January

4

3

2

3

5

4

4

4

4

4

6

8

9

8

8

8

8

8

9

9

10

9

8

6

4

4

4

4

3

4

4

_

6

10

2

Discharge 

(ton/d)

21

15

87

12

21

18

18

17

17

17

27

36

40

35

35

36

36

35

38

37

41

36

32

22

13

13

14

16

12

17

15

750.7

24

41

8.7

Mean 

streamflow 

(ffVs)

1,430

1,380

1,370

1,370

1,370

1,330

1,380

1,350

1,350

1,350

1,300

1,170

1,210

1,340

1,340

1,300

1,340

1,320

1,310

1,320

1,300

1,310

1,360

1,330

1,470

1,550

1,460

1,500

_

...

37,910

1,354

1,550

1,170

Suspended sediment

Mean 

concentration 

(mg/L)

1999

February

4

4

4

4

3

4

4

4

4

4

3

2

2

3

3

4

4

4

3

3

3

3

3

3

3

4

6

7

...

. 

4

7

2

Discharge 

(ton/d)

15

15

15

15

11

14

15

15

15

15

11

6.3

6.5

11

11

14

14

14

11

11

11

11

11

11

12

17

24

28

379.8

14

28

6.3

Mean 

streamflow 

(tf/s)

1,940

1,890

1,750

1,680

1,510

1,460

1,410

1,450

1,420

1,430

1,440

1,430

1,420

1,500

1,690

2,000

2,280

1,940

1,900

2,120

2,650

3,150

3,330

3,210

3,230

3,630

3,720

3,390

3,190

3,050

2,970

69,180

2,232

3,720

1,410

Suspended sediment

Mean 

concentration 

(mg/L)

March

18

33

12

7

6

5

4

7

6

5

6

4

5

6

7

10

16

12

11

17

17

27

29

21

17

23

24

17

14

14

14

13

33

4

Discharge 

(ton/d)

94

168

57

32

24

20

15

27

23

19

23

15

19

24

32

54

98

63

56

97

122

230

261

182

148

225

241

156

121

115

112

2,873

93

261

15

44 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
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1998 through September 1999 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/!!)

2,810

2,620

2,570

2,510

2,430

2,340

2,350

2,370

2,470

2,430

2,320

2,380

2,450

2,570

2,650

2,640

2,760

3,010

3,520

4,420

4,940

4,900

4,720

4,610

4,710

5,120

5,710

6,110

5,970

5,600

-

106,010

3,534

6,110

2,320

Suspended sediment

Mean 

concentration 

(rog/L)

April

12

10

10

9

7

7

7

8

7

6

6

7

8

8

8

8

9

10

13

18

23

21

17

16

17

20

23

26

24

20

13

26

6

Discharge 

(ton/d)

91

71

69

61

46

44

44

51

47

39

38

45

53

56

57

57

67

81

124

215

307

278

217

199

216

276

355

429

387

302

...

4,322

144

429

38

Mean 

streamflow

(ft'/s)

5,340

5,340

5,460

5,430

5,250

4,950

4,860

4,880

4,900

4,890

4,790

4,640

4,560

4,380

4,210

4,150

4,160

4,330

4,840

5,540

6,210

7,230

7,960

9,020

10,800

13,000

13,500

13,100

13,000

13,500

12,700

216,920

6,997

13,500

4,150

Suspended sediment

Mean 

concentration 

(mg/L)

1999

May

19

18

18

17

16

14

14

10

12

12

12

13

13

12

10

11

10

10

12

18

29

41

53

65

110

162

140

108

93

105

96

41

162

10

Discharge 

(ton/d)

274

260

265

249

227

187

184

132

159

158

155

163

160

142

114

123

112

117

157

269

486

800

1,140

1,580

3,210

5,690

5,100

3,820

3,260

3,830

3,290

35,813

1,160

5,690

112

Mean 

streamflow 

(«rVs)

11,500

11,200

11,900

14,000

14,400

13,500

12,300

11,100

10,300

9,300

8,400

7,790

7,560

7,870

8,760

9,530

10,400

10,500

10,400

10,200

9,510

8,940

8,590

7,910

7,770

7,650

6,900

6,270

5,820

5,620

285,890

9,530

14,400

5,620

Suspended sediment

Mean 

concentration 

(mg/L)

June

63

59

65

118

114

90

68

50

43

39

32

27

24

25

32

40

48

50

49

41

36

29

26

25

22

22

20

16

12

14

-

_

43

118

12

Discharge 

(ton/d)

1,960

1,780

2,090

4,460

4,430

3,280

2,260

1,500

1,200

979

726

568

490

531

757

1,030

1,350

1,420

1,380

1,130

924

700

603

534

462

454

373

271

189

212

38,043

1,270

4,460

189

TABLE 7 45
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1998 through September 1999 

(Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(frVs)

5,890

5,900

5,610

5,290

5,030

4,710

4,500

4,290

4,100

3,950

3,710

3,540

3,430

3,290

3,120

3,020

2,930

2,810

2,720

2,650

2,530

2,530

2,410

2,250

2,260

2,200

2,110

2,010

1,940

1,870

1,800

104,400

3,368

5,900

1,800

Suspended sediment

Mean 

concentration 

(mg/L)

July

14

14

14

12

12

10

7

6

8

9

10

10

11

9

7

6

6

6

6

6

6

6

5

5

5

6

6

6

6

6

5

_

8

14

5

Discharge 

(ton/d)

223

223

212

171

163

127

85

69

89

96

100

96

102

80

59

49

47

46

44

43

41

41

33

30

31

36

34

33

31

30

24

2,488

80

223

24

Mean 

streamflow 

(frVs)

1,730

1,710

1,690

1,680

1,680

1,710

1,740

1,730

1,610

1,580

1,550

1,580

1,780

1,810

1,820

1,830

1,780

1,700

1,630

1,600

1,510

1,500

1,450

1,430

1,290

1,220

1,250

1,400

1,340

1,410

1,380

49,120

1,585

1,830

1,220

Suspended sediment

Mean 

concentration 

(mg/L)

1999

August

6

6

7

7

7

8

8

8

8

8

8

8

7

7

8

7

7

8

9

9

9

9

12

13

19

10

7

5

5

5

6

_

8

19

5

Discharge 

(ton/d)

28

28

32

32

32

37

38

37

35

34

33

34

34

34

39

35

34

37

40

39

37

36

47

50

66

33

24

19

18

19

22

1,063

34

66

18

Mean 

streamflow

(frVs)

1,420

1,400

1,420

1,500

1,530

1,530

1,480

1 360

1,380

1,340

1,350

1,340

1,290

1,340

1,330

1,330

1,300

1,290

1,260

1,290

1,300

1,260

1,250

1,190

1,200

1,240

1,280

1,290

1,290

1,320

-

40,100

1,337

1,530

1,190

Suspended sediment

Mean 

concentration 

<mg/L)

September

6

6

7

7

8

8

8

7

6

6

5

5

5

5

6

6

6

6

6

6

7

7

7

6

6

5

5

5

5

4

_

6

8

4

Discharge 

(ton/d)

23

23

27

28

33

33

32

26

22

22

18

18

17

18

22

22

21

21

20

21

25

24

24

19

19

17

17

17

17

14

660

22

33

14

TOTAL FOR WATER YEAR 1999

STREAMFLOW-1,100,420 ft3/s 

SEDIMENT DISCHARGE-88,404.9 tons

46 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
Table 8. Chemical and suspended-sediment analyses of field replicates for water samples, upper Clark Fork basin, Montana 

[Abbreviations: ng/L, micrograms per liter; mg/L, milligrams per liter; mm, millimeter. Symbols: <, less than laboratory reporting level]

Station 

number Station name Date

H<1todtaTSS' Calcium, Magnesium, A£ c'

CaCO ,) 1 UIB/|J7 V"1 ^^

12323230

12323770

12324200

12331800

12334550

12340500

Blacktail Creek at Harrison Avenue,

at Butte

04-27-99

04-27-99

Warm Springs Creek at Warm Springs 06-22-99

Clark Fork at Deer Lodge

Clark Fork near Drummond

06-22-99

02-22-99

02-22-99

08-13-99

08-13-99

Clark Fork at Turah Bridge, near Bonner 05- 1 2-99

Clark Fork above Missoula

05-12-99

05-26-99

05-26-99

1020

1025

1210

1215

1540

1545

1615

1620

0905

0910

1610

1615

93

94

66

67

230

220

240

230

120

120

68

68

27

27

20

21

67

66

67

66

32

32

18

18

6.5

6.6

3.6

3.7

15

15

17

16

8.6

8.6

5.4

5.4

(Hg/L)

4

4

5

5

9

9

13

14

6

6

5

6

Arsenic,

(Hg/L)

2

4

4

3

7

7

13

13

5

5

2

3

Station 

number

12323230

12323770

12324200

12331800

12334550

12340500

Cadmium, 

Date recoverable

(Hg/D

04-27-99 <1

04-27-99 <1

06-22-99 <1

06-22-99 <1

02-22-99 <1

02-22-99 <1

08-13-99 <1

08-13-99 <1

05-12-99 <1

05-12-99 <1

05-26-99 <1

05-26-99 <1

Cadmium, 

dissolved

(HB/L)

0.1

<.l

<.]

<.]

<.|

<1

<.

<.

<.

<.

<.

<.

Copper, 

total 

recoverable

(Hg/L)

8

8

19

20

16

18

19

18

13

12

22

22

Copper, 

dissolved

(Hg/L)

3

3

3

3

5

4

5

5

3

3

2

2

Iron, 

total 

recoverable

(Hg/L)

810

810

460

380

220

260

370

360

310

320

2,200

2,400

Iron, 

dissolved

(Hg/L)

200

210

11

12

<10

<10

<10

<10

16

18

49

45

Lead, 

total 

recoverable

(Hg/L)

5

5

2

2

2

2

3

3

2

2

5

6

Station 

number

12323230

12323770

12324200

12331800

12334550

12340500

Lead, 

Date dissolved

04-27-99 .5

04-27-99 <.5

06-22-99 <.5

06-22-99 <.5

02-22-99 <.5

02-22-99 <.5

08-13-99 <.5

08-13-99 <.5

05-12-99 <5

05-12-99 <.5

05-26-99 <.5

05-26-99 <5

Manganese, 

total 

recoverable

60

60

93

94

91

90

130

130

46

49

ISO

180

Manganese, 

dissolved

(Hg/L)

35

36

41

41

51

52

8

8

5

6

15

14

Zinc, 

total 

recoverable

(Hg/

21

<40

<40

<40

30

20

34

30

<40

<40

40

36

Zinc, 

dissolved

(Hg/L)

<20

<20

<20

<20

<10

9

3

3

<20

<20

<20

<20

Sediment, 

suspended 

(Hg/L)

39

41

24

23

15

16

25

25

18

19

200

201

Sediment, 

suspended, 

diameter, 

percent finer

than 0.062 mm

92

92

57

59

72

74

89

86

84

82

85

84

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

samples, upper Clark Fork basin, Montana

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

Constituent and reporting unit

Calcium, dissolved, mg/L

Magnesium, dissolved, mg/L

Arsenic, total recoverable, ng/L

Arsenic, dissolved, ng/L

Cadmium, total recoverable, ng/L

Cadmium, dissolved, ng/L

Copper, total recoverable, ng/L

Copper, dissolved, (ig/L

Iron, total recoverable, ng/L

Iron, dissolved, ng/L

Lead, total recoverable, ng/L

Lead, dissolved, ng/L

Manganese, total recoverable, ng/L

Manganese, dissolved, ng/L

Zinc, total recoverable, ng/L

Zinc, dissolved, ng/L

Sediment, suspended, mg/L

Sediment, suspended, percent finer than 0.062 mm

Number of 

replicate pairs

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

Standard 

deviation, 

in units (+/-)

0.50

.29

.41

.71

.0

.0

.76

.29

63

3.2

.29

.0

.96

.58

3.3

.29

.82

1.4

Relative 

standard 

deviation, 

in percent (+/-)

1.3

3.1

5.7

12

.0

.0

4.7

8.5

8.5

6.3

8.9

.0

1.0

2.2

10

1.8

1.5

1.7

48 \\ater-qualit), bed-sediment, and biological data (October 1998 through September 1999) and statistical summaries of data for streams in the 

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

[Abbreviations. ng/L. micrograms per liter; mg/L. milligrams per liter]

Constituent and reporting unit

Calcium, dissolved, mg/L

Magnesium, dissolved, mg/L

Arsenic, total recoverable, ng/L

Arsenic, dissolved, ng/L

Cadmium, total recoverable, ng/L

Cadmium, dissolved, ng/L

Copper, total recoverable, ng/L

Copper, dissolved, ng/L

Iron, total recoverable, ng/L

Iron, dissolved, ng/L

Lead, total recoverable, ng/L

Lead, dissolved, ng/L

Manganese, total recoverable, ng/L

Manganese, dissolved, ng/L

Zinc, total recoverable, ng/L

Zinc, dissolved, ng/L

Number of 

replicate pairs

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

10

Standard 

deviation, 

in units (+/-)

0.16

.12

.44

.25

.02

.00

.43

.34

5.6

.73

.23

.00

.64

.31

3.0

.89

Relative 

standard 

deviation, 

in percent (+/-)

0.5

1.6

5.6

4.1

16

<1

3.8

9.9

.9

.8

10

<.l

.8

.9

18

36

Within limits of 

data-quality 

objective

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

'No

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

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

[Abbreviation ng/L, micrograms per liter]

Constituent and reporting unit

Arsenic, total recoverable, ng/L

Arsenic, dissolved, ng/L

Cadmium, total recoverable, ng/L

Cadmium, dissolved, ng/L

Copper, total recoverable, ng/L

Copper, dissolved. ng/L

Iron, total recoverable, ng/L

Iron, dissolved, ng/L

Lead, total recoverable, ng/L

Lead, dissolved, ng/L

Manganese, total recoverable, ng/L

Manganese, dissolved, ng/L

Zinc, total recoverable, ng/L

Zinc, dissolved, ng/L

Number of 

samples

5

5

5

5

5

5

5

5

5

5

5

5

5

5

95- percent 

confidence 

interval for spike 

recovery, 

in percent

97.8-108

95.4-122

99.9-107

92.6-109

102-108

99.5-116

94.3-101

90.0-103

85.2-107

87.9-107

91.8-100

86.3-106

88.9-97.7

92.9-101

Mean spike 

recovery, 

in percent

102.9

108.9

103.4

100.9

105.0

107.5

97.7

96.5

96.2

97.4

96.0

95.9

93.3

96.9

Within limits of 

data-quality 

objective

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

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

[Abbreviation: ng/L, micrograms per liter]

Constituent and reporting unit Number of samples

95-percent

confidence interval for

spike recovery,

in percent

Mean spike 

recovery, 

in percent

Within limits of

data-quality

objective

Arsenic, total recoverable, (ig/L 

Arsenic, dissolved, (ig/L 

Cadmium, total recoverable, |ig/L 

Cadmium, dissolved, ng/L 

Copper, total recoverable, (ig/L 

Copper, dissolved, (ig/L 

Iron, total recoverable, ng/L 

Iron, dissolved, (ig/L 

Lead, total recoverable, (ig/L 

Lead, dissolved, (ig/L 

Manganese, total recoverable, (ig/L 

Manganese, dissolved, ^ig/L 

Zinc, total recoverable, 

Zinc, dissolved, ng/L

5

5

5

5

5

5

5

5

5

5

5

5

5

5

96.4-111 

97.5-113 

100-106 

92.4-113 

97.5-104 

89.1-116 

93.5-101 

90.6-109 

93.7-108 

94.0-106 

92.8-107 

89.3-108 

91.1-101 

957-102

103.6

105.2

103.0

102.6

100.5

102.7

97.2

99.9

101.1

100.2

99.8

98.8

962

98.6

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes

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

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

Symbol: <, less than laboratory reporting level]

Specific 

conduct- p .' Calcium, 

Date Time ance, °ns'te . dissolved

onsile unitJ (mg/L) 

(MS/cm) unlts)

NOV 1998

17... 1800 3 5.5 E001

FEE 1999

22... 1800 2 5.6 E02

APR

28... 1600 3 5.4 E.01

MAY

11... 1700 2 5.5 <02

27... 0845 3 5.6 E.02

JUN

10... 0900 2 5.6 E.01

23... 0700 2 5.7 E.01

AUG

13.. 1245 2 62 .01

M?Bne- AIoetat' Arsenic, Crfntam. Cadmium, C^r'

Sf 5 *"- '^ -Sr

E0.002 <1 <1 <1 <0.1 <1

E003 <1 <1 <1 <1 <1

E.002 <1 <1 <1 < 1 <1

<.004 <1 <1 <1 <.l <1

.006 <1 <1 <1 <1 <1

<.004 <1 <1 <1 <1 <1

E.002 <1 <1 <1 <1 <1

E002 <1 <1 <1 <1 <1

Copper, ! n: Iron, \' 

Date dissolved . dissolved 

(MH/L) ra£^L1,l*! <Hg/L) "*£

NOV 1998

17.. <1 <10 <10 <1

FEE 1999

22... <1 <10 <10 <1

APR

28... <1 <14 <10 <1

MAY

11... <1 <14 <10 <1

27... <1 <14 <10 <1

JUN

10... <1 <14 <10 <1

23... <1 <14 <10 <1

AUG

13... <1 36 <10 <1

'ad,' Lead, ne^e? Manganese, Z'nc: Zinc, 

>tal . . dissolved total dissolved M. dissolved 

*5* (Mg/L) recoverable ,Mg/L) -'"e (Mg/L)

<0.5 <10 <4 <10 <20

<.5 <10 <3 <10 <20

<.5 <3 <3 <40 <20

<.5 <3 <3 <40 <20

<.5 <3 <3 <40 <20

<.5 <3 <3 <40 <20

<.5 <3 <3 <40 <20

<.5 <3 <1 <40 <1

52 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
Table 14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, August 1999

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

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

Station number 

(fig- 1)

12323600

12323750

12323770

12323800

461415112450801

461559112443301

4619031 12440701

12324200

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Spnngs

Warm Springs Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, 

near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek 

diversion, near Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, 

near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula 1

Number o: 

composite 

samples

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

f

Cadmium

26.5

4.5

1.3

4.0

6.5

5.0

4.3

4.4

3.5

<2

2.6

<.2

3.9

<2

1.5

1.2

Concentration, in |ag/g

Chromium

24.8

23.6

27.5

27.0

27.5

24.9

26.4

32.5

29.4

20.4

27.0

20.3

27.7

21.6

20.8

17.2

Copper

5,970

223

779

991

1,440

1,390

766

1,070

780

63

491

16

479

27

219

141

Iron

34,600

20,000

20,600

26,800

31,700

28,600

28,300

30,200

25,300

23,400

23,200

19,300

24,400

20,100

20,400

17,300

Lead

852

62

85

136

174

186

117

150

119

162

94

15

102

19

47

41

Manganese

2,200

3,100

6,030

6,330

5,000

4,030

1,810

4,910

1,660

4,570

1,740

478

1,080

544

1,370

1,080

Nickel

14.2

15.7

19.6

19.0

18.7

17.0

15.1

20.1

15.9

12.7

15.0

14.8

19.1

14.3

15.8

12.5

Silver

18.9

1.6

3.1

3.6

5.6

4.8

2.7

4.5

3.2

5.8

2.3

<4

1.0

<4

.8

.4

Zinc

6,600

686

396

1,120

1,490

1,430

907

1,320

1,080

650

947

47

1,080

67

547

380

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

TABLE 14 53
Table 15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, August 1999

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

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

Station number 

(fig. 1)

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

1234000

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Warm Springs Creek at Warm Springs

Clark Fork near Galen

Clark Fork below Lost Creek, near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek diversion, 

near Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, near Bonner

Blackfoot River near Bonner

Clark Fork above Missoula

Clark Fork below Missoula1

Number 

of composite r . 

samPles mium

2 4.2

2 <9

2 <.9

2 <.9

2 <.9

2 <.9

2 1.5

2 1.0

2 I.I

2 <2

2 1.0

2 <.2

2 .4

2 <.2

2 .4

2 <2

Concentration,

Chromium

11.8

9.1

12.0

15.0

9.3

14.7

13.0

15.3

17.9

6.5

16.7

6.4

10.1

8.7

10.2

6.8

Copper

902

30

238

318

238

440

244

356

278

18

223

3

84

12

72

16

Iron

18,300

9,600

12,700

20,600

12,600

19,700

16,400

16,300

16,000

10,100

15,200

5,290

9,270

11,500

13,800

8,420

Lead

198

10

38

48

41

76

47

61

48

63

50

<3

22

6

18

6

iniig/g

Manganese

748

1,000

2,440

1,900

1,290

1,280

876

709

554

1,800

949

72

299

207

810

150

Nickel

6.5

5.4

8.5

6.9

4.2

6.5

6.5

8.4

9.2

4.5

9.8

3.6

6.7

7.5

9.2

3.9

Silver

3.2

<8

<.8

.9

.8

1.4

<8

.9

.6

4.1

.7

<4

<4

<4

<4

<4

Zinc

1,730

131

275

477

365

626

368

471

525

220

603

10

271

34

263

58

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

54 Water-quality, bed-sediment, and biological data (October 1998 through September 1999) and statistical summaries of data for streams in the 

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

[Abbreviations: 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 for lead and silver]

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number of 

measurements

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

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

(Mg/g)

SRM sample 2709

0.4

130

35

35,000

19

538

88

.4

106

SRM sample 2711

41.7

47.0

114

28,900

1,160

638

20.6

4.6

350

Mean SRM recovery 

(percent)

133.9

65.6

90.0

88.0

87.0

94.0

87.9

-

95.0

98.5

57.9

95.9

83.0

95.6

85.1

91.8

76.9

100.9

95-percent confidence 

interval for SRM 

recovery 

(percent)

83.5-184

61.2-70.0

85.8-94.2

85.7-90.3

82.2-91.8

91.2-96.8

85.9-89.9

-

89.4-100

97.1-99.9

54.9-60.9

93.2-98.6

81.1-84.9

94.1-97.1

83.9-86.3

85.9-97.7

73.8-80.0

92.3-109.5

TABLE 16 55
ater-quality, bed-sediment, andbiologii 

1 Clark Fork Basin, Montana

S

0.

»S

£S

f

^*se

s 1

eraB1

if as

3

?^*

»B O.

itatistical si

ummaries of0.

» 

S Si S

t/1

I

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 hydrochloric acid used for reconstituting dried residue. Symbols: <, less than]

Station number Station name

1 2323600 S ilver Bow Creek at Opportunity 

12323750 Silver Bow Creek at Warm Springs

12323770 Warm Springs Creek at Warm Springs12323800 Clark Fork near Galen

46 1 4 1 5 1 1 245080 1 Clark Fork below Lost Creek, near Galen 4615591 12443301 Clark Fork near Racetrack46 1 903 1 1 244070 1 Clark Fork at Dempsey Creek diversion, near Racetrack 

12324200 Clark Fork at Deer Lodge

1 2324680 Clark Fork at Goldcreek 12331500 Flint Creek near Drummond

1233 1800 Clark Fork near Drummond1 23 345 1 0 Rock Creek near Clinton

12334550 Clark Fork at Turah Bridge, near Bonner1 2340000 Blackfoot River near Bonner 12340500 Clark Fork above Missoula1 23 53000 Clark Fork below Missoula

Dilution 

ratio

1:10 

1:101:10

1:10

1:10 

1:101:10 

1:101:5 

1:5

1:5

1:51:51:5 1:5

1:5

Trace-element concentration, in ng/mL

Cadmium

<0.005 

<.005<.005

<.005<.005 <.005<.005 <.005<.005 <.005

<.005

<.005<.005

<.005 

<.005

<.005

Chromium

<0.004 

<.004

<.004<.004

<.004 

<.004<.004 

<.004<.004 

<.004<.004<.004<.004

<.004 

<.004<.004

Copper

<0.008 

<.008<.008

<.008

<.008 

<.008<.008 <.008

<.008 

<.008<.008<.008<.008

<.008 

<.008

.010

Iron

<0.37

<.37<.37<.37

<.37 <.37<.37 <.37<.37 <.37

<.37

<.37<.37<.37 <.37

<.37

Lead

<0.018 

<.018<.018<.018

<.018 

<.018<.018 

<.018<.018 

<.018<.018<.018<.018

<.018 

<.018

<.018

Manganese

<0.036 

<.036<.036<.036

<.036 <.036

<.036 

<.036<.036 

<.036<.036<.036<.036

<.036 <.036

<.036

Nickel

<0.007 

<.007<.007

<.007

<.007 <.007

<.007 

<.007<.007 

<.007<.007<.007

<.007<.007 

<.007

<.007

Silver

<0.002 

<.002<.002<.002

<.002 <.002

<.002 

<.002<.002 

<.002<.002<.002

<.002

<.002 <.002<.002

Zinc

<0.020 

<.020

<.020

<.020

<.020 

<.020

<.020 <.020<.020 

<.020<.020<.020<.020

<.020 

<.020

<.020
Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 1999

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

Number of Concentration, in ng/g

Taxon

Brachycentrus spp.

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Hydropsyche occidentalis

Hydropsyche cockerelli

Hydropsyche occidentalis 

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche spp.

Hydropsyche cockerelli

Hydropsyche occidentalis

posite Cad- Chro- Cop- Jron 

samples mium mium per

12323600 Silver Bow Creek at Opportunity

1 5.8 0.7 846 730

12323750 Silver Bow Creek at Warm Springs

1 <.4 <4 22.4 453

5 .2 1.0 28.9 761

12323770 Warm Springs Creek at Warm Springs

1 1.9 2.9 102 872

2 .7 3.2 182 2,010

12323800 Clark Fork near Galen

1 1.4 1.5 48.7 816

Lead

17.9

<2.1

3.7

<8.7

7.4

6.3

4 .7 1.4 67.5 1,100 6.1 

461415112450801 Clark Fork below Lost Creek, near Galen

1 2.3 1.0 48.8 706

4 1.1 1.7 93.6 1,380

1 1.3 1.0 45.1 533

461SS9112443301 Clark Fork near Racetrack

1 <2.2 2.2 50.0 846

2 .8 1.3 64.1 1,190

<3.0

10.0

4.1

<10.9

6.7

Manganese

503

657

1,690

1,800

2,440

1,370

1,950 

1,230

3,240

1,230

1,690

3,220

Nickel

1.9

<1.7

.9

<7.0

3.2

<4.3

1.3

<2.4

1.5

<1.6

<8.7

1.3

Zinc

629

115

174

180

169

155

178 

151

254

143

155

194

461903112440701 Clark Fork at Dempsev Creek diversion, near Racetrack

Hydropsyche occidentalis

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Hydropsyche spp.

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

5 1.0 1.8 88.3 1,530

12324200 Clark Fork at Deer Lodge

1 1.8 1.6 57.4 977

4 1.2 1.5 94.3 1,190

12324680 Clark Fork at Goldcreek

4 4.1 1.2 54.6 518

2 .7 .8 69.0 223

1 2.4 1.8 58.6 1,080

2 1.7 1.7 64.6 1,070

12331500 Flint Creek near Drummond

2 5 1.6 16.1 1,260

1 <.3 1.4 12.5 1,440

12331800 Clark Fork near Drummond

2 1.9 1.2 36.8 614

3 1.6 1.2 106 335

2 1.0 1.3 43.8 927

2 1.2 2.1 57.6 1,300

11.8

<7.6

7.7

4.0

1.2

5.7

6.2

9.1

4.5

3.6

1.9

2.4

8.8

3,610

772

1,640

1,020

125

900

1,290

1,530

1,320

1,120

343

784

1,860

1.7

2.2

1.6

.6

.4

1.2

1.0

1.6

1.3

<1.2

.5

1.3

1.7

277

134

216

306

255

206

228

202

130

220

368

142

249

TABLE 18 57
Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 1999 (Continued)

Taxon

Number o 

composite 

samples

if Concentration, in |ig/g

Cad- Chromium mium

Copper

Iron Lead

Manganese

Nickel Zinc

12334510 Rock Creek near Clinton

Arctopsyche grandis 1 .3 .8

12334550 Clark Fork at Tnrah

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelh

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

3

1

1

2

3

2

1

2

3

2

2

2

1.5

1.0

1.0

1.1

12340500

.8

.8

.8

.7

12353000

1.2

.8

.7

.5

2.2

.4

2.5

2.3

81 471 <1.4 152 1 1 101

Bridec, near Bonner

48.5

39.3

62.6

56.6

1,310

90

1,510

1,370

5.1

.6

5.8

6.1

713

66

651

744

1.7

<.3

16

1.5

229

196

220

227

Clark Fork above Missoula

1.7

.9

2.1

3.2

40.0

51.5

40.4

51.3

1,070

218

1,900

2,300

2.8

.5

<2.7

5.5

988

122

931

2,370

1.4

<.8

2.3

2.3

200

249

156

230

Clark Fork below Missoula1

1.7

.6

2.2

1.5

27.7

62.5

38.4

25.1

987

152

1,560

1,000

2.0

.5

2.7

1.9

833

115

841

682

1.1

<.4

15

8

201

251

167

134

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

58 Water-quality, bed-sediment, and biological data (October 1998 through September 1999) and statistical summaries of data for streams in the 

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

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

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of measurements

12

12

12

12

'4

12

12

12

Certified concentration

(Mg/g)

SRM sample TORT-2

26.7

.77

106

105

.35

13.6

2.5

180

Mean SRM recovery 

(percent)

102

156

101

100

108

97.2

96.0

103

95-percent confidence 

interval for SRM 

recovery 

(percent)

101-104

155-156

97.1-104

94.5-106

108-109

96.6-97.7

95.9-96.1

93.7-112

Eighi samples were at or below the analytical detection limns

TABLE 19 59
Table 20. Trace-element analyses of procedural blanks for biota

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

Trace-element concentration, in ng/mL

Station 

number

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340500

12353000

Station Dilution 

name ratio Cadmium

Silver Bow Creek at Opportunity 1:1 <0.01

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

Warm Springs Creek at Warm Springs 1:1 <.01

Clark Fork near Galen 1:1 <.01

Clark Fork below Lost Creek, near Galen 1:1 <.01

Clark Fork near Racetrack 1:1 <.0 1

Clark Fork at Dempsey Creek diversion, 1:1 <.01 

near Racetrack

Clark Fork at Deer Lodge 1:1 <01

Clark Fork at Goldcreek 1:1 <.01

Flint Creek near Drummond 1:1 <.01

Clark Fork near Drummond 1:1 <.0 1

Rock Creek near Clinton 1:1 <.0 1

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

Clark Fork above Missoula 1:1 <.0 1

Clark Fork below Missoula 1:1 <.0 1

Chro- Copper Iron mium

<0.01 <0.03 <0.10

<.01 <.03 <.10

<01 <03 .37

<.01 <.03 <.10

<.01 <.03 <.10

<.01 <.03 <.10

<.01 <03 <.10

<.01 <03 <57

<.01 <03 .45

<01 <.03 <.10

<.01 <03 17

<.01 <03 <.10

<01 <.03 <.10

<.01 <.03 <10

<01 <.03 <.10

Lead

<0.05

<05

<05

<05

<05

<.05

<05

<05

<05

<.05

<.05

<05

<05

<05

<05

Manganese

<0.03

<.03

<03

<.03

<.03

<.03

<.03

<03

<.03

<.03

<.03

<.03

<03

<.03

<.03

Nickel

<004

<04

<.04

<04

<.04

<.04

<04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

Zinc

<0.04

<.04

<.04

<.04

<.04

<04

<.04

<.04

<.04

<.04

<.04

<04

<.04

<.04

<.04

60 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
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1999

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

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

insufficient data greater than minimum reporting level to compute statistic]

Property or constituent and reporting unit

Number of 

samples

Maximum Minimum

12323230-BLACKTAIL CREEK AT HARRISON AVENUE, AT BUTTE,

Period of record for water-quality data

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (uS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ug/L)

Arsenic, dissolved (ug/L)

Cadmium, total recoverable (ug/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L)

Lead, total recoverable (ug/L)

Lead, dissolved (ug/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

: March 1993-August 1995,

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

51

156

412

17.0

8.2

140

39

11

18

13

<1

.5

52

10

4,200

480

47

1

240

100

130

11

139

59

97

Mean

MONT.

Median

December 1996-Sep tern her 1999

3.1

116

2.0

7.3

38

11

2.7

2

1

<1

<.l

2

<1

250

24

<1

<5

30

17

<10

<3

2

.04

50

19

251

8.0

7.8

100

28

6.9

7

4

-

-

8

24

858

199

23

2 .3

65

42

2 12

24

19

2.2

83

9.3

245

7.0

7.8

100

29

6.7

6

4

<1

<.l

6

4

620

190

1

<.5

60

39

<10

<20

8

.2

86

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

through September 1999 (Continued)

Number of

Property or constituent and reporting unit Maximum Minimum Mean Median

samples

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

Period of record for water-quality data: March 1993-August 1995, December 1996-September 1999

Streamflow, instantaneous (ft3/s) 51 134 15 35 29

Specific conductance, onsite (uS/cm) 51 691 226 451 460

Temperature, water (°C) 51 17.0 1.5 9.9 9.0

pH, onsite (standard units) 51 7.8 7.2 7.5 7.5

Hardness, total (mg/L as CaCO3) 51 180 66 143 150

Calcium, dissolved (mg/L) 51 52 19 41 42

Magnesium, dissolved (mg/L) 51 13 4.5 10 10

Arsenic, total recoverable (ug/L) 51 45 8 16 14

Arsenic, dissolved (ug/L) 51 13 4 7 7

Cadmium, total recoverable (ug/L) 51 6 1 3 2

Cadmium, dissolved (ug/L) 51 6.2 .5 2.1 1.6

Copper, total recoverable (ug/L) 51 550 40 169 150

Copper, dissolved (ug/L) 51 300 12 73 60

Iron, total recoverable (ug/L) 51 7.400 250 1,480 820

Iron, dissolved (ug/L) 51 270 20 108 100

Lead, total recoverable (ug/L) 51 250 3 27 11

Lead, dissolved (ug/L) 51 2.4 <.5 2.8 .6

Manganese, total recoverable (ug/L) 51 1,600 245 682 670

Manganese, dissolved (ug/L) 51 1,700 210 619 630

Zinc, total recoverable (ug/L) 51 2,200 254 856 790

Zinc, dissolved (ug/L) 51 2,200 200 702 600

Sediment, suspended concentration (mg/L) 50 405 3 40 16

Sediment, suspended discharge (ton/d) 50 70 .14 5.2 1.2

Sediment, suspended (percent finer than 0.062 mm) 50 98 42 83 86

62 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
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1999 (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 (j^S/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

: March 1993-August 1995, December 1996-September 1999

54

53

53

53

53

53

53

53

53

53

53

53

53

53

53

53

53

53

53

53

53

54

54

54

361

593

18.0

8.9

200

55

15

240

34

49

41

3,900

450

24.000

310

650

51

10,000

9,300

15,000

13,000

801

781

95

26

202

0.0

7.2

60

18

3.4

11

1

1

.1

79

25

290

3

7

<.5

230

190

230

94

6

42

37

94

368

8.8

8.3

131

39

8.3

34

10

3

2.0

324

66

2,230

59

56

2 .8

801

660

866

534

76

37

76

64

368

9.0

8.2

130

39

8.2

18

9

2

1.2

160

51

990

33

21

.5

598

490

533

290

24

3.7

79

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

through September 1999 (Continued)

Property or constituent and reporting unit Maximum Minimum Mean Median

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT. 

Period of record for water-quality data: March 1993-September 1999

Streamflow, instantaneous (ft3/s) 60 662 24 181 141

Specific conductance, onsite (nS/cm) 58 614 249 430 426

Temperature, water (°C) 59 22.0 .5 10.8 12.0

pH, onsite (standard units) 58 9.3 8.0 8.8 8.8

Hardness, total (mg/L as CaCO3 ) 58 260 97 179 170

Calcium, dissolved (mg/L) 58 78 28 52 50

Magnesium, dissolved (mg/L) 58 19 5.9 12 11

Arsenic, total recoverable (ng/L) 58 94 12 27 24

Arsenic, dissolved (ng/L) 58 60 8 22 21

Cadmium, total recoverable (ng/L) 58 <1 <1 <1

Cadmium, dissolved (ng/L) 58 .3 <.l 2.1 <.l

Copper, total recoverable (ng/L) 58 80 5 25 21

Copper, dissolved (ng/L) 58 40 3 12 10

Iron, total recoverable (ng/L) 58 3,000 130 431 340

Iron, dissolved (ng/L) 58 93 <5 2 18 15

Lead, total recoverable (ng/L) 58 15 <1 23 2

Lead, dissolved (ng/L) 58 1.0 <.5 - <.5

Manganese, total recoverable (ng/L) 58 600 60 192 155

Manganese, dissolved (ng/L) 58 530 12 120 86

Zinc, total recoverable (ng/L) 58 180 <10 253 40

Zinc, dissolved (ng/L) 58 73 <3 2 12 7

Sediment, suspended concentration (mg/L) 60 229 2 15 8

Sediment, suspended discharge (ton/d) 60 279 .26 12 2.6

Sediment, suspended (percent finer than 0.062 mm) 59 97 43 82 85

64 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
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1999 (Continued)

Property or constituent and reporting unit

12323770-WARM

Number of 

samples Maximum Minimum Mean Median

SPRINGS CREEK AT WARM SPRINGS, MONT.

Period of record for water quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (ng/L)

Copper, dissolved (|ig/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (|ig/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

40

39

40

39

39

39

39

39

39

39

39

39

39

39

39

39

39

39

39

39

39

40

39

40

March 1993-September 1999

420

795

16.0

8.7

420

130

22

27

14

<1

<1

97

16

1,700

30

14

1.8

1,400

570

60

10

100

87

88

2.8

139

.5

7.4

66

20

3.6

3

2

<1

<.l

2

1

40

3

<1

<5

90

41

<10

<1

2

.09

55

124

295

8.6

8.3

144

44

8.3

8

5

-

-

25

4

408

11

23

-

261

153

2 15

2 3

25

14

75

95

266

9.0

8.3

130

39

7.3

6

4

<1

<1

11

3

160

10

1

<5

200

110

<40

<10

11

3.0

76

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

through September 1999 (Continued)

Property or constituent and reporting unit Number of 

samples

12323800--CLARK FORK

Period of record for water-quality

Streamflow, instantaneous (ftVs)

Specific conductance, onsite (|iS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (|ig/L)

Arsenic, dissolved (|ig/L)

Cadmium, total recoverable (|ig/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L)

Lead, total recoverable (ug/L)

Lead, dissolved (|ig/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

101

89

100

88

87

87

87

87

87

87

87

86

87

87

87

87

87

87

87

87

87

101

101

100

Maximum

NEAR GALEN,

Minimum

MONT.

Mean Median

data: July 1988-Sep tern her 1999

1,050

720

22.5

9.0

370

110

22

78

53

3

1

240

50

9,200

110

28

3

1,400

380

360

110

338

459

97

14

197

0.0

7.5

81

24

5.1

3

4

<1

<1

5

3

90

<3

<1

<5

80

31

<10

<3

2

12

41

235

422

9.5

8.5

185

55

12

21

15

2.3

2.1

38

11

649

2 18

24

2 .3

279

121

2 59

2 15

23

28

78

149

423

9.2

8.5

180

54

11

17

13

<1

<1

24

9

330

12

2

<5

200

89

50

10

10

3.3

78

66 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
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1999 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum

12324200-CLARK FORK AT DEER LODGE,

Period of record for water-quality data

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3 )

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (Hg/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

153

136

152

101

93

93

93

103

103

103

103

102

103

103

103

103

103

103

103

103

103

153

153

144

Minimum

MONT.

: March 1985-September

1,920

642

23.0

8.9

270

81

18

220

39

5

2

1,500

120

29,000

190

200

6

4,600

400

1,700

230

2,250

8,690

99

23

234

0.0

7.4

95

28

5.9

8

7

<1

<-l

10

4

60

<3

<1

<-5

30

1

10

<10

2

.29

40

Mean

1999

313

485

9.4

8.2

202

60

13

28

15

2 .6

2 -l

110

13

2,150

2 17

2 14

2 .5

319

44

124

2 16

89

205

70

Median

231

505

10.0

8.2

210

61

13

18

13

<1

<1

51

10

780

10

5

<.6

180

32

70

11

25

15

70

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

through September 1999 (Continued)

Property or constituent and reporting unit

12324590-LITTLE

Number of 

samples Maximum Minimum Mean Median

BLACKFOOT RIVER NEAR GARRISON, MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (|ig/L)

Arsenic, dissolved (|ig/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (|ig/L)

Copper, total recoverable (ng/L)

Copper, dissolved (|ig/L)

Iron, total recoverable (|ig/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (|ig/L)

Manganese, total recoverable (|ig/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

84

72

83

71

66

66

66

71

71

71

71

70

71

71

71

71

70

71

71

71

71

84

84

84

March 1985-September 1999

2,080

300

22

8.5

140

43

9.4

17

7

2

1

45

7

25.000

120

25

6

1,100

30

140

24

1,410

7,920

97

21

120

0.0

7.0

51

14

3.3

4

3

<1

<.l

<1

<1

20

<3

<1

<.5

<10

1

<10

<1

1

.08

49

313

221

8.1

8.0

101

29

6.8

7

5

2.3

-

2 5

22

1,330

237

23

2 .5

2?9

9

2 15

24

58

163

74

198

215

8.0

8.1

99

28

6.8

6

5

<1

<.l

3

2

310

27

<5

<6

30

8

<10

<20

10

6.6

78

68 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
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1999 (Continued)

Property or constituent and reporting unit

12324680-C1

Number of 

samples Maximum Minimum

ARK FORK AT GOLDCREEK MONT.

Period of record for water-quality data

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (uS/cm)

Temperature, water (°C)

pH. onsite (standard units)

Hardness, total (mg/L as CaCO3 )

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ug/L)

Arsenic, dissolved (ug/L)

Cadmium, total recoverable (ug/L)

Cadmium, dissolved (ug/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L)

Lead, total recoverable (ug/L)

Lead, dissolved (ug/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

59

58

59

58

58

58

58

58

58

58

58

57

57

58

58

57

57

58

58

58

58

59

59

59

: March 1993-September

3,920

496

20.0

8.7

230

68

15

75

20

2

.2

440

36

12,000

100

73

.8

1,100

43

510

26

752

7,960

93

87

207

0.0

7.9

86

26

5.1

8

6

<1

<.l

8

3

60

<3

<1

<.5

30

10

10

<3

2

.94

43

Mean

1999

902

358

9.1

8.3

157

46

10

18

10

-

--

56

8

1,220

221

28

--

157

21

65

28

71

360

74

Median

620

368

9.5

8.3

160

48

10

14

10

<1

<1

38

7

680

14

5

<5

116

20

49

5

28

47

78

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

through September 1999 (Continued)

Property or constituent and reporting unit Number of 

samples

12331500-FLINT CREEK NEAR

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

108

97

106

94

87

87

87

94

94

94

94

93

94

94

94

94

94

94

94

94

94

108

106

108

Maximum Minimum

DRUMMOND, MONT.

Mean Median

March 1985-September 1999

892

507

21.0

8.8

260

73

20

57

20

3

.1

32

7

7,200

240

87

7

1,600

120

290

27

556

904

98

4.2

134

0.0

7.5

59

16

4.3

7

5

<1

<.l

1

<1

70

3

<1

<5

50

14

<10

<3

3

.03

28

203

289

8.7

8.3

136

37

11

19

9

2.2

-

7

22

1,020

43

2 13

2.8

227

39

243

26

55

51

80

138

290

9.0

8.3

140

37

11

15

8

<1

<.l

5

2

572

28

8

<1

150

34

30

3

30

96

84

70 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
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1999 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean

149 

189 

.5

7.8 

74 

21

5.2

8

7 

<1

<.l

1,260

384

10.1

8.3

173

50

12

19

11

Median

12331800-CLARK FORK NEAR DRUMMOND, MONT. 

Period of record for water-quality data: March 1993-September 1999

Streamflow, instantaneous (ft3/s) 59 3,860

Specific conductance, onsite (|j.S/cm) 58 630

Temperature, water (°C) 59 21.0

pH, onsite (standard units) 58 8.5

Hardness, total (mg/L as CaCO3 ) 58 300

Calcium, dissolved (mg/L) 58 83

Magnesium, dissolved (mg/L) 58 22

Arsenic, total recoverable (ng/L) 58 62

Arsenic, dissolved (Mg/L) 58 20

Cadmium, total recoverable (ug/L) 58 2

Cadmium, dissolved ^g/L) 58 .2

907

392

11.0

8.3

180

52

12

16

10

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

56

56

58

58

54

54

58

58

58

58

59

59

59

360

21

8,800

150

56

1.2

880

50

490

21

530

4,720

91

5

1

50

<3

<1

<.5

20

8

<10

<3

2

1.9

38

56

7

1,360

223

2 11

2.3

184

18

285

28

85

475

73

33

6

698

11

5

<5

129

15

50

6

40

103

74

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

through September 1999 (Continued)

Property or constituent and reporting unit Number of ,. . , Maximum samples

12334510-ROCK CREEK

Period of record for water-quality

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ug/L)

Cadmium, dissolved (ug/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L)

Lead, total recoverable (Ug/L)

Lead, dissolved (ug/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (ug/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

83

74

83

73

65

65

65

71

71

71

71

69

70

71

71

69

69

71

71

71

71

83

83

83

NEAR CLINTON,

Minimum

MONT.

Mean Median

data: March 1985-September 1999

5,060

155

18

8.8

90

23

8.8

3

1

3

1

41

6

2,100

160

19

5

90

8

60

15

223

3,050

95

113

53

0.0

6.9

22

5.9

1.9

<1

<1

<1

<.l

<]

<1

20

5

<]

<5

<10

<1

<10

<3

1

31

35

1,060

103

8.0

7.9

48

13

4.1

2 .9

2 1

2 .4

-

24

2 1

357

39

22

2.6

2 18

22

29

23

25

172

69

660

94

8.0

7.9

43

11

3.7

<1

<1

<1

<.l

2

<1

180

35

<5

<.6

10

2

<10

<3

7

16

69

72 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
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin. Montana, March 1985 

through September 1999 (Continued)

 * . * * Number of Property or constituent and reporting unit

12334550-CLARK

Period of record

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3 )

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Maximum

FORK AT TURAH BRIDGE, NEAR

for water-quality data

156

131

155

102

92

92

92

101

101

101

101

99

100

101

101

97

97

101

101

101

101

156

156

Sediment, suspended (percent finer than 0.062 mm) 145

Minimum

BONNER,

: March 1985-September

9,560

483

22.0

8.8

210

59

14

110

17

4

1

500

25

19,000

190

100

7

2,000

37

1,100

39

1,370

34,700

98

296

140

0.0

7.4

58

16

3.9

5

4

<1

<.l

3

2

53

<3

<1

<5

10

1

<10

<3

2

3.5

27

Mean

MONT.

1999

1,950

306

9.1

82

133

37

9.4

11

6

2.4

-

46

6

1,400

22?

2 10

2.4

161

9

283

28

67

781

72

Median

1,170

327

9.5

8.2

135

38

9.4

8

5

<1

<.l

23

4

530

16

5

<.6

90

7

40

6

23

67

72

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

through September 1999 (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 (|aS/cm)

Temperature, water (°C)

pH. onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ug/L)

Copper, dissolved (ug/L)

Iron, total recoverable (ug/L)

Iron, dissolved (ug/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ug/L)

Manganese, total recoverable (ug/L)

Manganese, dissolved (ug/L)

Zinc, total recoverable (ug/L)

Zinc, dissolved (ug/L)

Sediment, .suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

114

91

114

74

67

67

67

74

74

74

74

71

72

74

74

70

70

74

74

74

74

114

114

112

March 1985-September 1999

13,400

294

20.5

8.7

140

37

13

4

2

2

1

34

7

3,600

100

25

8

180

11

60

15

271

7,670

98

344

130

0.0

7.5

55

14

4.9

<1

<1

<1

<1

<1

<1

20

<3

<1

<.5

<10

<1

<10

<1

1

1.1

42

2,820

204

8.9

8.2

100

26

8.8

2 1

2 .9

2 .4

-

27

22

583

220

24

2 1

238

23

2 10

23

35

642

79

1,340

200

9.0

8.3

94

24

8.3

1

<1

<1

<.l

5

1

250

14

1

<1

20

2

<10

<10

10

31

81

74 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
Table 21. Statistical summary of water-quality data for the upper Clark Fork basin, Montana, March 1985 

through September 1999 (Continued)

Property or constituent and reporting unit Number of ,, 

. Maximum samples

12340500-CLARK FORK ABOVE MISSOULA

Period of record

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite ((iS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (Hg/L)

Cadmium, dissolved (Hg/L)

Copper, total recoverable (ng/L)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (ng/L)

Lead, dissolved (ng/L)

Manganese, total recoverable ((ig/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

for water-quality data

122

99

119

79

79

79

79

79

79

79

79

77

78

79

79

74

74

79

79

79

79

122

122

Sediment, suspended (percent finer than 0.062 mm) 1 1 7

Minimum

, MONT.

Mean Median

: July 1986-September 1999

21,600

399

19.5

8.7

170

46

13

69

9

5

.1

400

11

13,000

200

78

1

1,100

230

1,100

16

824

21,900

99

720

142

0.0

7.9

61

14

5.3

2

1

<1

<.]

2

1

60

<3

<]

<.5

10

7

<10

<3

2

6.1

44

4,670

254

9.0

8.3

117

31

9.2

6

3

-

-

19

3

728

225

24

2.6

74

19

237

25

41

1,130

86

2.380

261

8.5

8.3

120

32

9.2

4

3

<]

<.l

8

2

270

16

2

<.5

40

15

20

3

12

66

90

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

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

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

August 1986 through August 1999

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

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

Number of samples represents the number of years that the constituent was analyzed, with each year represented by a single mean concentration of 

composite samples]

Number

Constituent of

samples

Maximum

Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY, MONT.

Period of record for fine-grained bed-sediment data: 1992-99

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

8

7

8

8

8

8

7

8

8

42.0

32.4

6,280

41,200

1,030

3,940

21.4

19.6

10,800

23.7 31.1

23.2 27.6

4,220 5,010

34,400 38,400

752 848

1.680 2,540

14.2 16.4

13.7 16.6

6,660 8,060

28.2

27.6

4,740

39.000

833

2,440

16.1

16.8

7,570

12323750-SILVER BOW CREEK AT WARM SPRINGS, MONT.

Period of record for fine-grained bed-sediment data: 1992-99

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

8

7

8

8

8

8

7

8

8

12.2

34.1

769

27,200

100

17,700

19.1

2.1

2,220

4.5 7.5

12.8 22.7

223 434

19,500 22,100

58 76

1,470 6,480

12.5 15.5

.3 M.4

620 1,160

6.7

23.6

351

20,800

74

5,590

15.7

'1.4

830

12323770-WARM SPRINGS CREEK AT WARM SPRINGS, MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

3

3

3

3

3

3

3

3

3

3.9

33.4

892

22,400

86

8,790

21.9

3.7

421

1.3 2.6

27.5 30.6

779 840

20,600 21,600

85 85

2,020 5,610

17.6 19.7

3.1 3.3

372 396

2.6

30.8

848

21,900

85

6.030

19.6

3.2

396

76 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
Table 22. Statistical summary of fine-grained bed-sediment data for the upper Clark Fork basin, Montana, 

August 1986 through August 1999 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number

MaxiConstituent of Minimum Mean

mum

samples

12323800-CLARK FORK NEAR GALEN, MONT.

Period of record for fine-grained bed-sediment data: 1987, 1991-99

10 20.1 4.0 10.4

7 33.9 22.1 28.3

10 2,300 991 1,350

10 39,800 22,600 29,600

10 235 116 152

10 15,600 2,780 8,460

7 23.2 17.7 19.8

10 5.5 <3.2 '3.8

10 3,560 1,120 1,920

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

Period of record for fine-grained bed-sediment data: 1996-99

4 9.0 6.5 7.7

4 34.5 27.5 31.7

4 2,050 1,360 1,650

4 32,700 30,800 31,600

4 197 168 182

4 5,900 3,540 4,600

4 19.9 17.8 18.8

4 7.0 4.2 5.9

4 1,680 1,280 1,480

461559112443301-CLARK FORK NEAR RACETRACK, MONT.

Period of record for fine-grained bed-sediment data: 1996-99

4 8.5 5.0 6.6

4 33.3 24.9 29.6

4 1,610 946 1,330

4 31,700 28,600 29,800

4 186 134 157

4 4,030 2,390 3,060

4 18.4 16.5 17.1

4 6.1 <3.3 '4.6

4 1,550 1,030 1,300

Median

92

29.9

1,230

28,400

144

7,440

19.3

'3.7

1,600

7.6

32.5

1,580

31,600

182

4,490

18.7

6.2

1,470

6.5

30.0

1,380

29,400

154

2.900

16.8

'5.4

1,310

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Period of record for fine-grained bed-sediment data: 1996-99

4 8.1 4.3 6.0

4 34.1 26.4 30.1

4 1,550 766 1,110

4 33,700 28,200 30,100

4 152 115 134

4 3,910 1,810 2,760

4 16.9 15.1 16.1

4 6.2 2.7 4.7

4 1,570 900 1,160

5.9

30.0

1.060

29,200

134

2,660

16.3

4.9

1,080

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

August 1986 through August 1999 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number

MaxiConstituent of Minimum Mean

mum

samples

12324200-CLARK FORK AT DEER LODGE, MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1990-99

12 9.0 4.4 6.8

7 43.9 19.5 33.1

12 4,180 837 1,510

12 35,300 22,600 28,700

12 242 121 161

12 6,020 1,460 2,820

7 21.1 15.0 17.8

12 7.9 2.4 4.7

12 1,730 977 1,340

12324590-HTTLE BLACKFOOT RIVER NEAR GARRISON, MONT.

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

4 1.5 .2 .8

2 52.9 22.1 37.5

4 85 38 60

4 30,700 16,100 24,200

4 53 36 41

4 2,700 905 1,390

2 21.9 13.6 17.8

4 .9 <.5 '.6

4 204 161 179

12324680--CLARK FORK AT GOLDCREEK, MONT.

Period of record for fine-grained bed-sediment data: 1992-99

8 6.2 3.5 5.4

7 48.9 29.4 35.8

8 1,080 653 833

8 30,600 20,500 25,900

8 152 88 114

8 2,610 1,180 1.940

7 18.6 15.0 16.8

8 4.8 2.3 3.5

8 1,320 1,070 1,160

12331500-FLINT CREEK NEAR DRUMMOND, MONT.

Period of record for fine-grained bed-sediment data: 1986, 1989, 1992-99

10 4.5 <2 '2.3

7 29.2 20.4 24.7

10 73 55 62

10 28,100 21,100 24.100

10 240 150 180

10 5,510 2,370 3,790

7 14.9 11.7 13.1

9 7.8 5.0 6.3

10 777 577 666

Median

6.8

35.4

1,140

29,500

157

2,380

17.6

4.5

1,350

.8

59

25,100

38

974

..

'.6

175

5.7

34.5

786

25,800

119

1,810

17.0

3.5

1,140

'2.4

24.3

63

23,500

176

3,740

12.7

6.4

661

78 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
Table 22. Statistical summary of fine-grained bed-sediment data for the upper Clark Fork basin, Montana, 

August 1986 through August 1999 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number

MaxiConstituent of Minimum Mean

mum

samples

12331800-CLARK FORK NEAR DRUMMOND, MONT.

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

II 5.4 2.6 4.4

7 35.4 17.0 30.0

II 747 469 560

11 27,000 16,500 22,900

11 135 83 101

11 2,780 1,220 1,850

7 16.8 15.6 15.6

11 4.7 <3.2 '3.0

II 1,230 939 1,080

12334510-ROCK CREEK NEAR CLINTON, MONT.

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

12 <l.5 <.2 '--

7 27.9 16.5 22.6

12 16 3 12

12 21,400 13,100 18,100

12 16 <3 '8

12 724 126 405

7 14.8 10.8 12.9

11 .8 <.3 '.4

12 58 36 48

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

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

10 5.2 3.1 3.8

7 34.7 15.3 26.4

10 635 300 420

10 24,400 15,100 20,400

10 115 49 80

10 2,270 671 1,260

7 19.1 11.6 15.3

10 3.9 1.0 2.2

10 1,160 775 941

12340000-BLACKFOOT RIVER NEAR BONNER, MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1991, 1993-96, 1998-99

9 <1.5 <.2 '--

6 25.8 15.1 20.7

9 27 16 22

9 20,200 17,100 17,100

9 20 <13 '12

9 672 298 500

6 14.3 11.7 13.0

9 .7 <.3 '.4

9 73 54 63

Median

4.3

32.6

551

23,800

99

1,880

15.7

'2.9

1,100

'<8

21.4

14

18,500

'8

403

13.0

'<5

48

3.7

27.7

384

22,000

80

1,200

16.2

2.2

913

'<7

21.8

21

18,100

'11

497

13.0

'<5

63

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

August 1986 through August 1999 (Continued)

Constituent

Number

of

samples

MaxiMinimum Mean

mum

Median

12340500-CLARK FORK ABOVE MISSOULA, MONT.

Period of record for fine-grained bed-sediment data: 1997-99

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

3

3

3

3

3

3

3

2

3

3.7 1.5 2.5

30.6 20.8 26.6

516 219 339

24,300 20,400 22,200

63 47 57

1,370 1,160 1,270

15.8 14.5 15.1

2.9 <3.2 '1.8

924 547 722

2.3

28.5

282

21,800

60

1,290

15.0

'.8

696

12353000-CLARK FORK BELOW MISSOULA. MONT.2 

Period of record for fine-grained bed-sediment data: 1986,1990-99

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

11

7

11

11

11

11

7

11

11

2.6

27.6

293

21.100

58

2,530

14.1

2.1

675

1.1

17.2

98

14,500

12

752

11.8

.4

319

1.7

22.2

163

18,600

38

1,440

13.0

1.2

430

1.8

21.5

141

19,500

38

1,270

13.3

1.3

436

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

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

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

values are below the detection level.

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

80 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
Table 23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, 

August 1993 through August 1999

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

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

of samples represents the number of years that the constituent was analyzed, with each year represented by a single mean concentration of composite 

samples]

Number

MaxiConstituent of

mum

samples

Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY, MONT.

Period of record for bulk bed-sediment data: 1993-95, 1997-99

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

6 12.7

6 16.2

6 1,550

6 29,300

6 300

6 1,670

6 8.9

6 4.8

6 3,420

4.2 7. 1

9.6 12.8

670 951

18,300 22,300

198 243

504 847

6.0 6.7

3.2 3.8

1,720 2,160

6.1

12.3

867

20,200

240

743

6.3

3.7

1,900

12323750-SILVER BOW CREEK AT WARM SPRINGS, MONT.

Period of record for bulk bed-sediment data: 1993, 1995-99

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

6 1.7

6 11.8

6 111

6 12,300

6 33

6 1,000

6 9.2

6 1.3

6 303

<0.9 'l.O

9.1 10.3

20 59

7,200 10,100

<10 '15

209 698

4.8 6.4

<.3 '.5

93 177

'.9

10.0

54

10,300

'11

776

5.5

'.6

147

12327700-WARM SPRINGS CREEK AT WARM SPRINGS, MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

3 1.0

3 12.0

3 238

3 12,700

3 38

3 2,650

3 8.5

3 1.1

3 275

<8 '.6

9.7 11.2

203 215

8,980 10,900

18 30

1,220 2,100

5.7 7.3

<.8 '.8

146 190

'<9

11.8

205

10,900

34

2,440

7.8

'.9

148

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

August 1993 through August 1999 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number

MaxiConstituent of Minimum Mean

mum

samples

12323800-CLARK FORK NEAR GALEN, MONT.

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

7 6.0 <.9 '3.0

7 23.0 4.2 13.6

7 685 223 392

7 31,300 9,930 20,400

7 158 41 76

7 5,410 900 2,000

7 12.5 4.9 7.7

7 1.9 .7 '1.3

7 1,280 417 671

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

Period of record for bulk bed-sediment data: 1996-99

4 3.1 <.9 '2.0

4 17.5 9.3 13.0

4 763 238 463

4 21,000 12,600 16,700

4 104 41 74

4 1,740 1,260 1,420

4 8.2 4.2 6.7

4 2.8 <3.4 '1.9

4 787 365 577

4615591 12443301-CLARK FORK NEAR RACETRACK, MONT.

Period of record for bulk bed-sediment data: 1996-99

4 3.4 <.9 '2.0

4 16.4 12.4 14.0

4 594 361 442

4 19,700 16,200 18,000

4 87 66 77

4 1.680 759 1,300

4 9.9 5.5 7.3

4 2.6 <3.2 '1.9

4 743 472 594

Median

'2.6

14.8

318

20,600

64

1,540

6.9

'1.6

653

'2.2

12.5

426

16.600

75

1,340

7.2

'1.9

577

'2.0

13.7

407

18,000

77

1,390

6.9

'1.7

581

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Period of record for bulk bed-sediment data: 1996-99

4 3.9 1.5 2.5

4 20.9 13.0 16.9

4 651 244 474

4 25,400 16,400 20,700

4 89 47 70

4 1,940 825 1,380

4 12.8 5.5 8.7

4 2.8 <8 '1.7

4 804 368 556

2.4

16.8

501

20.500

73

1,360

8.2

'1.8

526

82 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
Table 23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, 

August 1993 through August 1999 (Continued)

Number

MaxiConstituent of

mum

samples

Minimum Mean Median

12324200-CLARK FORK AT DEER LODGE, MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

7 3.1

7 24.5

7 691

7 25,000

7 85

7 2,060

7 12.3

7 2.8

7 777

1.0 2.2

12.1 17.4

281 424

13,200 18,700

45 71

653 1,090

7.7 9.6

<.7 'l.5

456 565

2.1

16.1

383

17,900

74

1,020

10.1

'1.6

529

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON, MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

2 .7

2 33.2

2 20

2 21,000

2 18

2 420

2 15.2

2 <1.6

2 86

<1.2 '.6

14.7 23.9

19 20

15,600 18,300

12 15

308 364

8.6 11.9

<.7 '--

73 79

-

-

-

12324680-CLARK FORK AT GOLDCREEK, MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

7 5.2

7 33.2

7 858

7 24,900

7 86

7 2,600

7 15.9

7 3.7

7 1,020

1.1 3.0

17.6 23.3

243 464

15,500 19,400

46 65

554 1,220

9.1 12.0

<.7 'l.8

525 717

2.4

21.1

370

18,600

71

1,191

12.0

'1.6

676

12331500-FLINT CREEK NEAR DRUMMOND, MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

7 3.2

7 13.9

7 40

7 15,700

7 120

7 3.200

7 8.0

7 5.8

7 429

<.2 'l.2

4.9 9.8

18 27

8,630 12,900

51 82

1,150 2,230

4.5 6.0

3.3 4.4

190 302

'.9

10.7

25

13,400

80

2,240

5.9

4.1

325

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

August 1993 through August 1999 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number

MaxiConstituent of Minimum Mean

mum

samples

12331800-CLARK FORK NEAR DRUMMOND, MONT.

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

7 3.9 <l.6 '2.0

7 29.5 13.8 21.0

7 605 173 314

7 21,800 14,100 17,200

7 78 35 53

7 1,510 711 1.110

7 14.2 9.0 11.2

7 3.5 .5 '1.7

7 939 434 646

12334510-ROCK CREEK NEAR CLINTON. MONT.

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

7 <1.5 <2 '--

7 

7735

14.3 6.4 9.1

7 11,100 5,290 8.040

7 <13 <3 '5

7 265 72 170

7 8.2 3.6 5.5

7 <1.6 .1 '.3

7 29 10 18

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

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

7 2.9 .4 '1.4

7 23.8 6.9 15.1

7 336 75 189

7 19,100 9,270 13,400

7 67 21 37

7 1,470 234 650

7 14.0 6.4 9.4

7 2.9 <3 'l.O

7 769 271 475

12340000-BLACKFOOT RIVER NEAR BONNER, MONT.

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

3 <1.2 <2 '--

3 17.7 6.7 11.0

3 19 12 15

3 16,600 10,300 12,800

3 10 6 8

3 305 179 230

3 9.8 7.5 8.3

3 <7 <4 '--

3 58 33 42

Median

'1.8

20.1

235

16,300

50

1.140

10.4

'1.6

603

'<8

8.8

5

7,410

'5

186

5.1

'.3

17

'1.6

15.5

182

13,200

35

414

8.8

'.4

508

'<8

8.7

14

11,500

8

207

7.6

'<5

34

84 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
Table 23. Statistical summary of bulk bed-sediment data for the upper Clark Fork basin, Montana, 

August 1993 through August 1999 (Continued)

Constituent

Number 

of

samples

MaxiMinimum

mum

Mean Median

12340500-CLARK FORK ABOVE MISSOULA, MONT.

Cadmium

Chromium

Copper 

Iron

Lead

Manganese 

Nickel 

Silver

Zinc

Period of record for bulk bed-sediment data: 1997-99

3 <1.6 .4

3

3 

3

3

3 

3 

3

3

18.2 9.7

129 43 

16,000 11,500 13,

30 7

810 228 

10.3 8.2 

<3.3 <.4

387 145

'.5

12.7

81

800

18

530 

9.2 

'.8

265

<.8

10.2

72 

13,800

18

553 

9.2 

'.6

263

12353000--CLARK FORK BELOW MISSOULA, MONT.2

Cadmium

Chromium

Copper 

Iron 

Lead

Manganese 

Nickel 

Silver

Zinc

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

7 <1.5 <.2

7

7 

7 

7

7 

7 

7

7

12.6 4.4

77 16 

11.300 5,830 8, 

19 <10

444 150 

7.1 3.5 

<1.6 <.3

172 58

'.5

7.4

40 

230 

'8

332 

5.1 

'.4

112

'<.5

6.8

30 

8,420 

'6

368 

4.5 

'.4

101

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

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

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

values are below the detection level.

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

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

August 1999

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

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

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

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

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

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

Number of

Constituent composite Maximum Minimum

samples

12323600-SILVER BOW CREEK AT OPPORTUNITY,

Mean

MONT.

Median

Period of record for biological data: 1992, 1994-95, 1997-99

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

Brachycentrus spp.

3 12.5 5.8

3 1.1 .7

3 846 587

3 730 335

3 17.9 7.4

3 503 231

3 1.9 <.l

3 888 629

Hydropsyche cockerelli

5 6.3 4.1

5 8.0 1.0

5 462 269

5 1,180 689

5 21.7 19.0

5 718 180

5 2.1 .7

5 898 749

Hydropsyche tana

6 9.2 4.8

6 11.5 .9

6 456 10.5

6 1,520 857

6 21.0 15.6

6 969 307

6 1.8 .7

6 1,070 760

12323750-SILVER BOW CREEK AT WARM SPRINGS

Period of record for biological data: 1992-99

Hydropsyche cockerelli

21 2.1 .2

21 1.3 .5

21 96.9 22.4

21 1,240 351

21 5.7 .3

21 2,450 491

21 1.8 .3

21 276 115

10.0

.8

675

476

11.1

364

1.0

735

4.9

3.7

365

931

20.3

460

1.4

818

6.8

4.5

236

1.100

18.6

634

1.4

961

, MONT.

.8

.8

45.4

691

3.3

981

.8

184

11.6

.7

592

363

7.9

357

1.0

687

4.7

3.1

333

953

20.1

434

1.6

805

6.9

1.8

298

1,050

18.3

675

1.6

1,020

.6

.8

42.5

732

3.0

828

.8

174

86 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
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1999 (Continued)

Number of

Constituent composite Maximum Minimum

samples

Mean Median

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1992-99

Hydropsyche occidentalis

9 1.1 .2

9 1.7 .3

9 46.5 22.8

9 1,040 372

9 4.3 <2.3

9 2,250 1,200

9 1.8 .7

9 202 149

Hydropsyche spp.

4 2.3 .4

4 1.4 .5

4 47.6 34.9

4 773 561

4 5.1 1.9

4 1,100 443

4 1.9 <4

4 285 141

12323770-WARM SPRINGS CREEK AT WARM SPRINGS

.5

.9

32.4

744

'3.4

1,760

1.1

175

1.1

.8

40.9

680

2.9

725

'.8

195

, MONT.

.3

.9

29.7

764

'3.6

1,780

1.0

174

.9

1.2

40.6

693

4.7

678

'.5

177

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arctopsyche erandis

3 2.4 1.9

3 2.9 1.4

3 102 95.6

3 1,040 684

3 5.6 <6.3

3 2,280 1,340

3 <7.0 1.8

3 222 180

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.

-

-

-

..

2.2

2.0

98.9

866

'4.4

1,810

'2.5

200

.8

3.2

182

2,010

7.4

2,440

3.2

169

<9.3

1.6

94.8

1,150

<16.7

956

2.0

129

2.1

1.8

98.8

872

<8.7

1,800

2.3

197

--

-

-

-

--

-

-

-

--

-

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

August 1999 (Continued)

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

12323800-CLARK FORK NEAR GALEN, MONT.

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

Hvdrousvche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

14

14

14

14

14

14

14

14

2.7

3.3

181

1,510

11.0

2,950

3.1

299

1.3

.8

48.7

816

1.2

1,070

1.0

136

1.7

1.6

92.9

1,170

7.0

1,920

1.6

209

1.6

1.5

91.9

1,160

7.7

1,840

1.3

210

Hvdropsvche morosa group

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

5

5

5

5

5

5

5

5

3.2

4.6

185

1,890

12.4

3,960

3.6

349

2.4

1.8

156

1,360

7.1

2,360

1.9

292

2.5

2.6

173

1,510

8.5

3,500

2.3

309

2.4

2.2

175

1.430

7.9

3,860

2.1

303

Hvdropsvche accidentally

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

28

28

28

28

28

28

28

28

1.7

6.6

106

1,920

13.5

4,070

3.5

278

.6

.7

49.2

642

1.6

1,220

.8

170

1.1

1.7

77.5

1,180

6.5

2,340

1.5

197

1.0

1.4

74.5

1,140

6.2

2,170

1.4

193

Hvdropsvche tana

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc - -

1.5

1.4

92.9

1.340

9.0

2,160

2.1

206 -

Hvdropsvche spp.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

4

0

4

4

4

0

0

4

3.5

154

1,540

135

329

2.6

..

135

1.190

10.5

279

3.0

148

1.400

12.2

308

3.0

__

152

1,450

12.4

313

88 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
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1999 (Continued)

Number of

Constituent composite Maximum Minimum

samples

Mean Median

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-99

Hvdropsvche cockerelli

5 2.8 2.2

5 2.5 1.0

5 147 48.8

5 1,900 706

5 14.8 12.1

5 1,850 1.230

5 1.9 1.1

5 250 151

Hvdropsvche occidentalis

14 1.8 .9

14 3.3 1.3

14 157 52.1

14 1,920 963

14 12.4 6.6

14 3,440 1,270

14 1.7 .9

14 283 174

Hvdropsvche spp.

4 1.8 1.2

4 2.4 .9

4 122 45.1

4 1,410 533

4 20.5 4.1

4 1,980 799

4 2.8 1.4

4 225 143

461559112443301-CLARK FORK NEAR RACETRACK,

Period of record for biological data: 1996-99

Hvdropsvche cockerelli

6 1.9 1.1

6 2.7 .7

6 109 50.0

6 1,370 846

6 10.5 6.1

6 1,690 646

6 1.4 1.0

6 199 139

2.4

1.9

120

1,550

13.1

1,520

1.6

218

1.3

1.9

102

1,400

9.7

2,280

1.3

230

1.4

1.6

89.0

1,120

10.4

1,490

1.9

183

MONT.

1.5

1.8

78.3

1,060

8.3

1.090

1.2

172

2.3

2.0

141

1,730

12.7

1,590

1.6

231

1.6

1.9

120

1,520

11.5

1,850

1.5

231

1.4

1.6

94.3

1,270

8.5

1,590

1.4

183

1.6

1.8

81.0

1,030

8.7

963

1.3

177

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

August 1999 (Continued)

Number of

Constituent composite Maximum Minimum

samples

Mean Median

461559112443301-CLARK FORK NEAR RACETRACK. MONT. -Continued

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-99

Hydropsyche ocddentalis

\ 1 2.2 .7

11 2.6 1.1

11 160 59.5

11 1,880 1,030

11 11.7 4.3

11 3,480 1,090

11 1.7 1.1

11 255 181

Hydropsyche spp.

..

..

..

-

1.3

1.9

103

1,470

9.6

2,030

1.3

225

1.0

.7

82.9

1,140

5.7

910

1.1

151

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-99

Arctopsyche erandis

..

..

-

--

Hydropsyche cockerelli

2 1.6 .9

2 1.3 1.0

2 143 87.6

2 1,290 831

2 8.4 6.8

2 697 487

2 1.9 1.6

2 180 162

1.7

<2.4

30.8

340

<14.5

510

1.0

87

1.2

1.2

115

1,060

7.6

592

1.8

171

1.4

2.0

93.5

1,450

9.7

2,100

1.2

229

-

-

-

-

-

MONT.

-

-

-

-

90 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
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1999 (Continued)

Constituent

Number of 

composite Maximum Minimum 

samples

Mean Median

461903112440701-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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-99

Hvdropsyche occidentalis

12 1.7 .7

12 2.0 1.2

12 163 74.9

I.I

1.7

98.1

12 1,660 1,100 1,480

12 13.8 9.7

12 3,990 826 2,

12 2.4 1.2

12 292 222

Hydropsyche spp.

2 1.7 1.6

2 2.1 1.4

2 140 104

2 1,610 1,070 1,

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, 1990-99

Arctopsyche srandis

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

18 2.3 .8

18 3.2 .4

18 136 54.7

11.3

710

1.5

250

1.6

1.8

122

340

11.8

892

1.6

202

'2.2

'.8

52.0

606

'3.8

554

l_

159

1.4

1.7

94.6

18 3,340 490 1,170

18 18.2 4.3

18 1,030 396

18 2.4 .3

18 391 132

9.4

689

1.3

183

1.0

1.8

87.1

1,500

11.3

2,370

1.4

238

-

-

_

-

-

1.3

1.8

100

1,050

8.9

686

1.3

180

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

August 1999 (Continued)

Number of

Constituent composite Maximum Minimum

samples

Mean Median

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1986-87, 1990-99

Hydropsyche occidentalis

30 2.7 .8

30 2.6 .6

30 162 49.5

30 1,930 558 1

30 16.2 3.5

30 2,840 649 1

30 12.9 1.0

30 299 166

Hydropsyche spp.

3 2.0 1.2

0

3 222 103

3 2,220 1,110 1

3 15.0 5.6

0

0

3 203 185

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON

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

Arctopsyche erandis

10 .5 .2

10 1.6 .6

10 14.0 9.1

10 654 177

10 1.3 .5

10 596 318

10 .6 .4

10 179 113

Claassenia sabulosa

5 .5 .1

5 .9 .7

5 36.1 20.0

5 319 98

5 <1.2 <4

5 71.0 46.7

5 .7 .5

5 233 191

1.3

1.9

111

.420

10.9

,650

1.9

233

1.6

145

,520

8.8

195

, MONT.

.3

.8

11.4

284

.8

479

.5

149

.3

.8

29.5

174

l__

57.8

.6

205

1.3

1.9

110

1,460

10.8

1,720

1.5

227

1.6

Ill

1,240

5.7

197

.3

.8

11.5

235

.8

496

.5

145

.2

.8

31.4

144

'<6

56.7

.5

202

92 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
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1999 (Continued)

Number of 

Constituent composite Maximum Minimum 

samples

Mean Median

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

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

Hvdropsvche cockerelti

..

..

..

..

..

..

Hvdropsvche occidentalis

2 <.7 .3

2 2.3 1.3

2 15.2 15.1

2 1,340 426

2 2.3 <3.7

2 554 434

2 1.1 .8

2 137 110

12324680-CLARK FORK AT GOLDCREEK, MONT.

Period of record for biological data: 1992-99

Arctovsvche srandis

21 6.6 1.4

21 3.3 .8

21 129 28.8

21 2,360 339

21 10.9 2.3

21 1,220 592

21 1.8 .2

21 326 165

Claassenia sabulosa

15 3.5 .6

15 1.6 .3

15 81.7 33.0

15 296 63.0

15 1.7 .5

15 179 50.6

15 .7 .2

15 296 166

.6

1.6

28.4

478

3.6

399

1.2

123

.3

1.8

15.2

883

2.1

494

1.0

124

2.7

1.4

57.9

817

4.5

843

.8

217

1.6

.7

55.7

174

1.0

101

.3

247

-

-

-

-

-

-

-

-

--

2.5

1.0

55.6

610

3.7

842

.7

190

1.1

.6

56.2

178

1.1

91.6

.3

258

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

August 1999 (Continued)

Number of

Constituent composite Maximum Minimum

samples

Mean Median

12324680-CLARK FORK AT GOLDCREEK, MONT.-Continued

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1992-99

Hydropsyche cockerelli

14 26 .6

14 4.7 .7

14 188 33.5

14 3,250 589

14 16.2 4.5

14 954 538

14 2.3 .6

14 240 137

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

14 1.7 .7

14 3.9 .4

14 156 26.4

14 2,720 466

14 15.7 2.9

14 1,800 530

14 2.5 .8

14 242 97

1.8

2.5

92.8

1,390

8.3

719

1.4

195

1.4

1.4

60.5

1,050

4.6

804

1.2

167

1.3

1.5

64.8

1,130

6.9

1,090

1.2

189

1.8

2.0

66.9

1,210

6.5

670

1.3

204

1.4

1.4

62.7

1.130

4.6

822

1.2

170

1.4

1.5

58.4

1,040

6.0

1,020

1.1

190

12331500-FLINT CREEK NEAR DRUMMOND, MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1986, 1992-99

Arctopsyche erandis

35 .8 .1

35 4.7 .6

35 21.7 8.7

35 2,460 606

35 17.5 3.7

35 2,480 679

35 2.7 .6

35 275 141

.4

1.9

15.0

1,370

8.8

1,470

1.3

198

.4

1.8

15.0

1,330

7.8

1,340

1.3

188

94 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
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1999 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of

Constituent composite Maximum Minimum Mean

samples

12331500-FLINT CREEK NEAR DRUMMOND, MONT.-Continued

Period of record for biological data: 1986, 1992-99

Hydropsvche cockerelli

8 .7 .2 .4

8 4.0 1.0 1.8

8 28.3 9.5 18.1

8 3,290 996 1,780

8 17.9 3.1 11.3

8 1,440 401 1.020

8 2.3 .9 1.9

8 193 85 157

Hydropsyche occidentatts

6 1.0 .2 .6

6 17.6 .7 4.6

6 26.4 15.1 19.3

6 2,550 912 1,720

6 29.2 5.8 17.7

6 2,690 1,400 1,860

6 6.9 .8 3.2

6 243 128 182

Hvdrovsyche spp.

< 3

14

12.5

1,440

4.5

1,320

1.3

130

Hydropsyche tana

2 <1.2 <.l '--

2 10.3 .6 5.4

2 16.0 5.4 10.7

2 1,320 729 1,020

2 15.3 5.0 10.2

2 1,400 1,180 1,290

2 3.1 .5 1.8

2 139 107 123

12331800-CLARK FORK NEAR DRUMMOND, MONT.

Period of record for biological data: 1986, 1991-99

Arctopsvche erandis

24 3.8 .7 1.7

24 2.5 .2 1.1

24 89.2 18.2 38.7

24 1,660 240 666

24 11.8 2.1 4.9

24 2,010 462 884

24 1.9 .2 .7

24 308 142 196

Median

.4

1.5

18.1

1,680

12.0

1,130

2.2

180

.6

1.8

18.0

1,780

19.3

1,760

2.9

185

-

-

--

-

-

-

-

1.5

1.0

35.1

613

4.2

736

.7

190

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

August 1999 (Continued)

Number of 

Constituent composite Maximum Minimum 

samples

Mean Median

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1986, 1991-99

Claassenia sabulosa

27 2.8 .3

27 3.3 .3

27 130 18.0

27 380 76.0

27 2.9 .2

27 410 45.9

27 1.1 .1

27 469 140

Hydropsyche cockerelli

18 2.3 .7

18 3.5 .4

18 156 37.2

18 2,500 506

18 15.0 5.1

18 982 549

18 2.0 .5

18 240 134

Hydropsvche 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

14 2.0 .7

14 8.1 .4

14 118 13.3

14 2,060 424

14 13.5 2.9

14 2,920 619

14 2.4 .5

14 283 157

Hydropsyche spp.

1

0

1

1

1

0

0

1

1.4

.8

66.7

161

1.0

156

.3

271

1.5

1.9

74.2

1,300

9.1

762

1.2

191

1.2

2.3

55.2

1,570

8.9

1,610

1.5

239

1.2

2.4

56.9

1,240

8.8

1,510

1.4

221

2.6

85.0

940

9.1

«

260

1.5

.6

63.2

127

.8

144

.2

248

1.6

1.7

63.1

1,030

8.0

753

1.2

191

1.2

2.2

55.8

1,600

9.0

1,620

1.5

240

1.2

2.1

55.7

1,300

8.7

1,210

1.6

222

96 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
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1999 (Continued)

Constituent

Number of 

composite 

samples

Maximum Minimum Mean Median

12334510-ROCK CREEK NEAR CLINTON, MONT.

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

Arctopsvche erandis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

32

32

32

32

32

32

32

32

.4

2.9

15.7

991

<2.9

454

1.6

189

.06

.5

4.7

191

.1

113

.2

84

.2

1.2

8.6

517

'.4

249

.8

127

.2

1.0

8.3

464

'.4

226

.9

124

Claassenia sabulosa

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

16

16

16

16

16

16

16

16

.3

1.8

40.7

129

1.0

76.3

.9

264

.05

.4

18.1

49.8

.1

15.7

.1

164

.2

.8

29.8

90.7

.3

35.0

.3

205

.1

.6

30.0

93.1

.3

33.6

.3

207

Hvdropsvche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

3

3

3

3

3

3

3

3

<.2

1.0

13.1

609

<1.1

258

.9

99

<.2

.9

6.0

485

<1.1

192

.4

82

'--

.9

8.6

530

'--

219

.6

89

<2

.9

6.6

497

<I.l

208

.4

86

Hvdropsvche occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

4

4

4

4

4

4

4

4

<1.0

2.4

17.6

752

6.0

268

1.7

144

<.3

.9

9.6

520

1.2

169

.6

99

'--

1.6

12.0

642

3.0

228

1.2

121

<.3

.9

10.2

648

1.2

215

.9

117

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

August 1999 (Continued)

Number of

Constituent composite Maximum

samples

Minimum Mean Median

12334510-ROCK CREEK NEAR CLINTON, MONT.-Continued

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data:

Hydropsyche spp.

3 .3

3 2.1

3 16.2

3 1,140

3 <3.1

3 462

3 1.3

3 135

12334550-CLARK FORK AT TURAH BRIDGE,

Period of record for biological data:

Arctopsyche grandis

32 2.7

32 4.1

32 125

32 2,870

32 13.2

32 893

32 2.6

32 276

Claassenia sabulosa

23 2.5

23 2.0

23 79.2

23 181

23 1.6

23 139

23 .6

23 283

Hydropsyche cockerelli

21 1.7

21 8.0

21 118

21 2,530

21 12.1

21 788

21 26

21 228

1987, 1991-99

<5

1.1

11.6

837

<1.8

299

.8

117

'.2

1.6

14.3

1,000

!__

399

1.1

126

.2

1.7

15.0

1,030

<2.9

437

1.1

126

NEAR BONNER, MONT.

1986, 1991-99

.6

.6

20.1

420

2.1

351

.4

152

.3

.4

38.3

58.6

.2

42.0

.1

144

.6

1.0

26.4

688

2.2

426

.6

148

1.4

1.8

42,2

1,060

4.5

625

1.1

201

1.2

.7

56.9

105

.6

78.1

.2

221

1.0

2.2

52.0

1.280

5.4

584

1.2

186

1.5

1.7

34.1

908

3.7

625

.9

197

.9

.6

54.4

102

.6

696

.1

230

.9

1.7

42.5

1,060

5.0

560

1.2

180

98 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
Table 24. Statistical summary of biological data for the upper Clark Fork basin. Montana. August 1986 through 

August 1999 (Continued)

Number of

Constituent composite Maximum Minimum

samples

Mean Median

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

Period of record for biological data: 1986, 1991-99

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Hydropsyche morosa group

2 1.3 1.1

2 4.6 2.4

2 84.1 26.8

2 1,800 986

2 6.6 <7.8

2 1,320 537

2 1.7 1.3

2 231 171

Hydropsy che occidentalis

16 1.8 .3

16 3.1 .6

16 102 34.1

16 2,310 472

16 12.2 3.0

16 1,510 454

16 1.9 .6

16 235 145

Hydropsyche spp.

..

..

..

..

..

..

-

12340000-BLACKTOOT RIVER NEAR BONNER,

1.2

3.5

55.4

1,390

5.2

928

1.5

201

.9

1.8

49.6

1,140 1,

6.1

756

1.1

192

1.3

2.4

84.1

1,800

<7.8

537

1.3

171

MONT.

-

-

-

--

.9

1.6

42.2

010

5.4

672

1.0

183

-

-

-

-

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Arctopsyche srandis

9 .3 <.l

3 1.8 1.2

9 13.4 9.9

9 1,230 108

9 2.1 .5

3 517 389

3 1.2 .8

9 143 123

'.2

1.4

11.8

596

1.2

435

1.0

134

'.2

1.3

12.0

617

.9

398

.9

135

TABLE 24 99
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1999 (Continued)

Number of 

Constituent composite Maximum 

samples

Minimum Mean Median

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

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Claassenia sabulosa

9 .2

3 .9

9 88.5

9 199

9 .6

3 127

3 .3

9 329

Hydropsyche occidentalis

12 .5

12 2.7

12 20.6

12 1,930

12 1.9

12 527

12 1.8

12 150

Hydropsyche spp.

.1

.5

19.0

68.0

.4

44.2

.1

117

.1

.8

12.0

1,050

.8

414

.9

117

1996, 1998

.1

.7

44.5

124

.5

74.6

.2

204

.2

1.8

14.6

1,410

1.3

472

1.3

134

.6

1.6

13.9

1,120

2.9

525

28

132

.1

.7

41.0

114

.6

52.6

.2

194

.2

1.7

14.4

1,380

1.2

460

1.2

130

-

-

-

100 Water-quality, bed-sediment, and biological data (October 1998 through September 1999) and statistical summaries of data for streams in the 

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

August 1999 (Continued)

Constituent

Number of

composite Maximum Minimum

samples

Mean Median

12340500-CLARK FORK ABOVE MISSOULA, MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1997-99

Arctopsvche erandis

11 1.8 .5

11 3.0 1.3

11 77.6 22.3

II 2,340 708

11 6.8 1.2

11 1,040 476

1 1 2.0 .7

11 235 155

Claassenia sabulosa

4 2.0 .6

4 1.1 .4

4 61.9 37.8

4 246 95.0

4 3.1 .5

4 136 75.2

4 <1.3 <.3

4 307 191

Hydropsyche cockeretti

6 1.3 .8

6 4.1 2.1

6 96.1 40.4

6 3,590 1,900

6 6.3 5.3

6 1,180 781

6 2.4 1.4

6 226 156

Hydropsyche occidentalis

4 1.1 .7

4 3.2 2.8

4 76.5 46.5

4 2.400 2,010

4 7.7 5.0

4 2,460 939

4 2.3 1.9

4 232 210

.9

1.7

36.9

1,160

3.3

779

1.2

187

1.3

.8

47.9

167

M.4

107

l_

250

1.0

3.2

66.6

2,450

5.8

930

2.0

199

.9

3.0

57.2

2,220

6.5

1,930

2.1

225

.8

1.7

36.8

1,050

3.3

782

1.2

177

1.3

.9

46.0

163

'.5

109

'<.7

250

1.0

3.2

64.7

2,250

5.9

904

2.1

200

.9

3.0

52.9

2,220

6.6

2,160

2.2

230

12353000-CLARK FORK BELOW MISSOULA, MONT.2

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1986, 1990-99

Arctopsvche erandis

20 1.5 .3

20 2.7 .5

20 38.0 9.4

20 1,500 343

20 3.2 .9

20 1,090 511

20 1.6 .4

20 217 106

.8

1.4

22.0

810

1.9

713

.9

154

.8

1.4

20.3

832

1.9

710

.9

148

TABLE 24 101
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1999 (Continued)

Number of 

Constituent composite 

samples

Maximum Minimum

12353000-CLARK FORK BELOW MISSOULA

Mean Median

, MONT.2-Continued

Period of record for biological data: 1986, 1990-99

Claassenia sabulosa

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

31

31

31

31

31

31

31

31

1.3

1.2

66.4

240

1.3

168

.3

286

.2

.05

31.1

66.6

.1

48.9

.1

146

.6

.5

47.5

109

.4

99.9

.2

209

.6

.5

47.1

101

.4

99.3

.2

203

Hydropsvche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

28

28

28

28

28

28

28

28

1.1

3.4

45.7

2,000

3.6

1,180

1.7

172

.2

.8

12.4

645

1.2

353

.5

77.4

.5

2.0

30.6

1,300

2.3

720

1.2

147

.6

2.0

34.2

1,320

2.4

663

1.3

156

Hydropsvche ocddentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

13

13

13

13

13

13

13

13

1.1

3.5

38.2

1,420

4.2

1,460

2.2

193

.2

.2

18.9

482

.7

575

.5

112

.5

1.5

26.1

959

2.2

859

1.0

142

.5

1.6

27.6 

1,000

1.9

812

.9

145

Hydropsyche spp.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

-

-

-

-

-

-

-

-

.5

.8

20.8

894

1.1

756

1.1

124

-

-

-

-

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

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

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

all values are below the detection level. 

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

102 Water-quality, bed-sediment, and biological data (October 1998 through September 1999) and statistical summaries of data for streams in the 

Upper Clark Fork Basin, Montana