U.S. Department of the Interior 

U.S. Geological Survey

Water-Quality, Bed-Sediment, and Biological Data 

(October 1996 through September 1997) and 

Statistical Summaries of Data for Streams in the 

Upper Clark Fork Basin, Montana

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

Ellen V. Axtmann

Open-File Report 98-407

In cooperation with the

U.S. ENVIRONMENTAL PROTECTION AGENCY
U.S. Department of the Interior

BRUCE BABBITT, Secretary

U.S. Geological Survey

Thomas J. Casadevall, Acting Director

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

descriptive purposes only and does not imply endorsement by the 

U.S. Government

Helena, Montana 

August 1998

For additional information write to:

District Chief 

U.S. Geological Survey 

Federal Building, Drawer 10076 

Helena, MT 59626-0076

Copies of this report may be purchased from:

U.S. Geological Survey 

Branch of Information Services 

Box 25286 

Denver, CO 80225-0286
CONTENTS

Page

Abstract................................................................................................................................................................................. 1

Intrcxluction.............................................................................................................^ 1

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

Water-quality data .............................................................................................................................................................^ 4

Methods .................................................................................................................................................................^ 4

Results. .................................................................................................................................................................^ 5

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

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

Methods........................................................................................................._^ 9

Results.. ......................................................................................................................................^ 10

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

Biological data....................................................................................................................................................................... 11

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

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

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.................. 3

2. Properties and constituents analyzed in samples of water, bed sediment, and biota from the upper

Clark Fork basin, Montana.......................................................................................................................... 4

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 1996 through September 1997.......... 16

5.-7. Daily streamflow and suspended-sediment data, October 1996 through September 1997, 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 1997....... 53

15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, August 1997 ................... 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 1997......................................... 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 1997.............................................................................................................................. 61

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

August 1986 through August 1997.............................................................................................................. 76

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

through August 1997 ................................................................................................................................... 81

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

August 1997................................................................................................................................................. 86

CONVERSION FACTORS AND ABBREVIATED WATER-QUALITY UNITS

_________________ Multiply _______________ By _____________ To obtain

cubic foot per second (ft3/s) 0.0283 1 7 cubic meter per second

foot (ft) 0.3048 meter (m)

gallon (gal) 3.785 liter (L)

gallon (gal) 3,785 milliliter (ml)

inch (in.) 25.4 millimeter (mm)

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

mile (mi) 1 .609 kilometer

ounce (oz) 28.35 gram (g)

part per million 1 microgram per gram (ng/g)

square mile (mi ) 2.59 square kilometer 

___________ ton per day (ton/d) ______________ 907.2 ______________ kilogram per day

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

°F = 9/5 (°C) + 32 

Abbreviated water-quality units used in this report:

mcrograms per gram 

[ig/L micrograms per liter 

Hg/mL micrograms per milliliter

jaS/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.

iv Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Water-Quality, Bed-Sediment, and Biological Data 

(October 1996 through September 1997) and Statistical 

Summaries of Data for Streams in the Upper Clark Fork 

Basin, Montana

By Kent A. Dodge, Michelle I. Hornberger, and Ellen V. Axtmann

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 

1996 through September 1997 (water year 1997). 

Data for 15 bed-sediment and 15 biological stations were obtained in August 1997. 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 collected periodically 

during water year 1997. Daily values of streamflow, suspended-sediment concentration, and suspended-sediment discharge are given for three 

stations. Bed-sediment data include trace-element 

concentrations in the fine-grained and bulk fractions. Biological data include trace-element concentrations in whole-body tissue of aquatic benthic 

insects. Quality-assurance data are reported for 

analytical results of water, bed sediment, and 

biota. Statistical summaries of water-quality, bedsediment, and biological data are provided for the 

period of record at each station since 1985.

INTRODUCTION

The Clark Fork originates near Warm Springs in 

western Montana at the confluence of Silver Bow and 

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

of stream from Silver Bow Creek in Butte to the Clark 

Fork at Milltown Reservoir, six major tributaries enter: 

Blacktail Creek, Warm Springs Creek, Little Blackfoot 

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

Principal surface-water uses in the 6,000-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 may 

accumulate to potentially toxic levels.

Concern about the potential toxicity of tailings to 

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

to characterize the aquatic resources in the upper Clark 

Fork basin to guide and monitor remedial cleanup 

activities. A long-term data base was considered neeAbstract
Base from U.S. Geological 

Survey, State base map, 

1:1,000,000,1966

MONTANA 

.Helena

Study area

EXPLANATION

12324200 STATION AND NUMBER 

461903112440701 MISCELLANEOUS SITE AND NUMBER 

STREAMFLOW GAGING 

A Continuous record 

A Periodic measurement 

WATER QUALITY, BED SEDIMENT, BIOTA 

«V Periodic water quality 46 

V> Daily suspended sediment 

V" Once-annual bed sediment 

~V Once-annual biota

10 20 MILES

10 20 KILOMETERS

Figure 1 . Location of study area.

essary 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). Trace-element data for bed 

sediment and biota (aquatic benthic insects) have been 

collected intermittently since 1986 at selected sites as 

part of studies on bed-sediment contamination and 

bioaccumulation of metals conducted by the USGS

National Research Program (Axtmann and Luoma, 

1991; 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

2 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
pre-1996 status (water-quality sampling at the Clark 

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

annual variability in selected constituents.

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

15 bed-sediment and 15 biological stations in the upper 

Clark Fork basin collected from October 1996 through 

September 1997 (water year 1997). Quality-assurance 

data are presented for water quality, bed sediment, and 

biota. Statistical summaries also are provided for 

water-quality, bed-sediment, and biological data collected since 1985.

SAMPLING LOCATIONS AND TYPES OF 

DATA

Sampling stations in the upper Clark Fork basin 

are located on both 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. Data for 15 bedsediment 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 

1997 are listed in tables 4 through 20 at the back of the 

report. Statistical summaries of water-quality, bed-sedTable 1. Type and period of data collection at sampling stations in the upper Clark Fork basin, Montana

[Abbreviation: P, present (1997). Symbol: -, no data]

Station 

number («g. 1)

12323230

12323250

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324590

12324680

12331500

12331800

12334510

12334550

12340000

12340500

12353000

Station name

Blacktail Creek at Harrison

Avenue, at Butte

Silver Bow Creek below

Blacktail Creek, at Butte

Silver Bow Creek at

Opportunity

Silver Bow Creek at Warm

Springs

Warm Springs Creek at Warm

Springs

Clark Fork near Galen

Clark Fork below Lost Creek,

near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek

diversion, near Racetrack

Clark Fork at Deer Lodge

Little Blackfoot River near

Garrison

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge,

near Bonner

Blackfoot River near

Bonner

Clark Fork above Missoula

Clark Fork below Missoula3

Continuousrecord 

streamflow

10/83-P

07/88-P

03/72-09/79,

04/93-P

10/83-P

07/88-P

-

-

-

10/78-P

10/72-P

10/77-P

08/90-P

04/93-P

10/72-P

03/85-P

10/39-P

03/29-P

10/29-P

Periodic 

water quality1

03/93-08/95,

12/96-P

03/93-08/95,

12/96-P

03/93-08/95,

12/96-P

03/93-P

03/93-P

07/88-P

-

-

--

03/85-P

03/85-P

03/93-P

03/85-P

03/93-P

03/85-P

03/85-P

03/85-P

07/86-P

03/85-08/95

Daily 

suspended 

sediment

-

03/93-09/95

04/93-09/95

-

-

-

-

03/85-08/86,

04/87-P

-

-

-

-

-

03/85-P

07/86-03/87,

06/88-09/95

07/86-03/87,

06/88-01/96

03/96-P

-

Fine-grained 

bed sediment2

-

-

07/92-P

07/92-P

08/95, 08/97

08/87, 08/9 1-P

08/96-P

08/96-P

08/96-P

08/86, 08/87,

08/90-P

08/86, 08/87, 08/94

07/92-P

08/86, 08/89.

07/92-P

08/86, 08/87,

08/9 1-P

08/86, 08/87,

08/89, 08/9 1-P

08/86, 08/9 1-P

08/86, 08/87,

08/91,08/93-96

08/97

08/86, 08/90-P

Bulk 

bed , 

sediment2

-

08/93-08/95, 08/97

08/93, 08/95-P

08/95, 08/97

08/93-P

08/96-P

08/96-P

08/96-P

08/93-P

08/94

08/93-P

08/93-P

08/93-P

08/93-P

08/93-P

08/93-08/94

08/97

08/93-P

Biota2

-

07/92, 08/94,08/95, 08/97

07/92-P

08/95, 08/97

08/87, 08/9 1-P

08/96-P

08/96-P

08/96-P

08/86,08/87,08/90-P

08/87, 08/94

07/92-P

08/86, 07/92-P

08/86, 08/9 1-P

08/87, 08/9 1-P

08/86, 08/9 1-P

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

08/96

08/97

08/86, 08/90-P

'Onsite measurements of physical properties and laboratory analyses of selected major ions, trace elements, and suspended sediment.

laboratory analyses of trace elements.

3Bed sediment and biota sampled about 30 miles downstream from water-quality station to conform to previous sampling location.

SAMPLING LOCATIONS AND TYPES OF DATA
iment, and biological data collected since 1985 are 

given in tables 21-24 at the back of the report.

Quality assurance of data was maintained through 

the use of documented procedures designed to provide 

environmentally representative data. Acceptable performance of the procedures was verified with qualitycontrol samples that were collected systematically to 

provide a measure of the accuracy, precision, and bias 

of the environmental data and to identify problems 

associated with sampling, processing, or analysis.

WATER-QUALITY DATA

Water-quality data consist of measurements of 

physical properties and concentrations of chemical and 

physical constituents analyzed in stream samples. 

Samples were collected 5 to 8 times per year on a 

schedule designed to describe seasonal and hydrologic 

variability. In addition, 21 supplemental samples were 

collected by a contract observer at Clark Fork at Turah 

Bridge, near Bonner and Clark Fork above Missoula to 

better define chemical changes 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 

(1988). 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), USGS 

(1977), 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 Arvada, 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).

Table 2. Properties and constituents analyzed in samples of water, bed 

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

Property

Streamflow

Specific conductance

PH

Temperature

Water

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

4 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Ciark Fork Basin, Montana
Cross-sectional water samples also were collected for analysis of suspended sediment whenever 

periodic water-quality samples were collected. These 

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

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

the USGS sediment laboratory in Helena, Mont., 

according to methods described by Guy (1969) and 

Lambing and Dodge (1993).

At the three daily suspended-sediment stations 

(table 1), suspended-sediment samples were collected 

2 to 8 times per week. These samples were collected 

by local contracted 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 1996 through September 1997 

(water year 1997) 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 1997 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 (1988), 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 

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

WATER-QUALITY DATA
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. Replicate 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 laboratory analytical precision independent of 

possible effects on precision 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 limits for 

precision and bias of laboratory results. Comparisons 

of quality-control data to data-quality objectives are 

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

data in a consistent manner. Data that did not meet the 

objectives were evaluated for acceptability, and corrective action was taken, when appropriate.

The precision of analytical results for a constituent can be determined by estimating a standard deviation of the differences between replicate measurements for several sets of samples. These replicate measurements may consist either of individual analyses of 

a pair of samples considered to be essentially identical 

(field replicates) or multiple analyses of an individual 

sample (laboratory replicates). The differences in concentration between replicate analyses can be used to 

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

O (1)

where 

S standard deviation of the difference in 

concentration between replicate analyses,

difference in concentration between each 

pair of replicate analyses, and

number of pairs of replicate analyses.

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

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

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

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

6 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

Montana

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

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)

Detectability

Minimum 

reporting 

level, 

in units

0.02 mg/L

.01 mg/L

1 ng/L

1 (Jg/L

1 ng/L

.1 (Jg/L

1 |jg/L

1 |jg/L

10 ug/L

3 ug/L

1 ug/L

.5 ug/L

10 ug/L

1 ug/L

10 ug/L

3 ug/L

1 mg/L

1 percent

Data-quality objectives

Precision

Maximum relative 

standard deviation 

of laboratory 

replicate analyses, 

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

-

~

where

RSD 

S

RSD = - x 100 

x

= relative standard deviation, 

= standard deviation, and

(2)

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 20 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. Concentrations less than the minimum reporting 

level (censored values) were included in the calculations by arbitrarily substituting a value of one-half the 

reporting level.

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 were within

WATER-QUALITY DATA
the 20-percent relative standard deviation limits for all 

constituents (table 10). The precision data, therefore, 

indicate acceptable reproducibility of replicate analyses.

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 85.7 to 

106.4 percent. The mean spike recovery for spiked 

stream samples ranged from 84.3 to 107.1 percent. The

95-percent confidence intervals (Taylor, 1987) for the 

mean of spike recovery for each constituent analyzed 

in stream samples (table 12) did not exceed a 25-percent deviation from an expected 100-percent recovery, 

with the exception of dissolved arsenic and totalrecoverable copper and zinc. The exceedances outside 

of the acceptable 25-percent recovery limits were 

minor, ranging from 25.6 to 29 percent. The principal 

factor contributing to exceedance of the 25 percent 

deviation is the small number of spiked sample sets (3) 

used to complete the statistics. Because all mean spike 

recoveries were within the 25 percent limit, spike 

recoveries for each trace element were considered to be 

within the limits of data-quality objectives and indicate 

acceptable analytical performance for stream samples.

High or low bias is indicated if the confidence 

interval does not include 100 percent recovery. All 

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

percent, except for total-recoverable cadmium. Totalrecoverable cadmium recoveries were low, with a 95- 

percent confidence interval ranging from 75.0 to 93.6 

percent. Because of the small number of spiked sample 

sets (3), and mean spike recoveries that met data-quality objectives, no adjustments were made to analytical 

results for stream samples on the basis of spike recoveries.

Analytical results for field blanks are presented in 

table 13. A field blank with constituent concentrations 

equal to or less than the minimum reporting level for 

the analytical method indicates that the entire process

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

spike concentration

(3)

8 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
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 minimum reporting 

level (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 minimum reporting level 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 minimum reporting level 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 minimum reporting level. 

There was only one occurrence of a value equaling 

twice the minimum reporting level (calcium), 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 

fractions. Bed-sediment samples are collected onceannually during low, stable flow conditions to facilitate 

data comparisons among years.

Methods

Bed-sediment samples were collected in August 

1997 using protocols described by E.V. Axtmann (U.S. 

Geological Survey, written commun., 1994). Samples 

were collected from the surfaces of streambed deposits 

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

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

stream. Three composite samples of fine-grained bed 

sediment and one composite sample of bulk bed sediment were collected at each site.

Individual samples of fine-grained bed sediment 

were collected by scooping material from the surfaces 

of three to five randomly selected deposits along pool 

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

This collection process was repeated three times to 

obtain three composite samples. Each composite sample was wet-sieved onsite through a 0.064-mm 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 are not sieved and 

generally are 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 

Boulder, Colo. Fine-grained and bulk bed-sediment 

samples were oven-dried at 60 °C and ground using an 

acid-washed ceramic mortar and pestle. Duplicate aliquots of approximately 0.6 g of sediment from each of 

the three composite fine-grained bed sediment samples 

were digested using a hot, concentrated nitric acid 

reflux according to methods described by Luoma and 

Bryan (1981). Triplicate aliquots were 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-|im 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 

assigned a sequential number and submitted blind 

(without station identification) to the Geology Department at the University of Montana, Missoula, Mont., to 

be analyzed for cadmium, chromium, iron, lead, manganese, nickel, and zinc using Inductively Coupled 

Argon Plasma Emission Spectroscopy (1CAPES). 

Copper and silver were analyzed by flame atomic

BED-SEDIMENT DATA
absorption (AA) at the USGS National Research Program laboratory in Boulder, Colo.

Results

Concentrations of trace elements measured in 

samples of fine-grained and bulk bed sediment collected during August 1997 are summarized in tables 14 

and 15, respectively. Liquid-phase concentrations, in 

|^g/mL, that were analyzed in the reconstituted aliquots 

of digested bed sediment were converted to solid-phase 

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

, _ )^g/mL x volume of digested sample, in mL ,.. 

dry weight of sample, ing 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, 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 (SRM) are commercially prepared materials that have certified concentrations of trace elements. Replicate analyses of standard

reference materials 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 

standard reference materials for bed sediment is summarized in table 16. Two standard reference materials 

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 standard reference 

materials under such conditions serve 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, chromium, and silver for the low-concentration range (SRM 2709), and chromium for the highconcentration range (SRM 2711). Chromium had the 

lowest recovery (60.6 and 64.0 percent) of all the elements. There were two notable high recovery anomalies in the low-range SRM 301 percent for silver and 

296 percent for cadmium. The reason for both high 

recoveries is believed to be the result of analyzing concentrations very close to the detection limit, coupled 

with signal enhancement resulting from matrix interference. Because very few bed-sediment samples have 

cadmium and silver concentrations as low as SRM 

2709, 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

10 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
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 |ig/mL, 

which is equivalent to parts per million. Determination 

of the significance of a detectable blank concentration 

is based on the magnitude of the equivalent solid-phase 

concentration, in |ig/g, relative to the ambient concentration of the trace element in bed-sediment samples. 

Because sample weights of individual aliquots may 

vary, the relative significance of blank concentrations 

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

solid-phase concentration, then the blank concentration 

is subtracted to remove potential contamination bias. 

Almost all procedural blanks had concentrations less 

than analytical detection levels. No detectable concentrations were twice the detection level, except for iron. 

None of the detectable concentrations in blanks were 

greater than 10 percent of the ambient concentration, 

with the exception of the 1:10 dilution for sample G 

(table 17). Anomalously high concentrations of iron, 

lead, manganese, and zinc were measured in this one 

blank, but after reviewing all replicate analyses of the 

bed-sediment digests, no environmental samples 

appeared to be similarly affected. 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 analysis of trace elements 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., Order Trichoptera (caddisflies); Arctopsyche grandis, Order Trichoptera; and Claassenia 

sabulosa, Order Plecoptera (stoneflies). Samples of 

each taxon were stored separately, by genus, in acidwashed plastic containers. Containers were kept on ice 

in the field while the insects were allowed to evacuate 

the gut contents in ambient stream water for a period of 

six to eight hours. Excess water then was drained and 

insects were frozen for transport to the laboratory.

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-|im filter, and 

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

Results

Concentrations of trace elements in whole-body 

tissue of aquatic insects collected during August 1997 

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 in 

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 genera of Hydropsyche were collected for 

this study: Hydropsyche occidentalis and Hydropsyche morosa group. Two species of Hydropsyche 

were identified within the morosa group (H. cockerelli

BIOLOGICAL DATA 11
and//, tana). Results of analyses are listed for the individual species within the morosa group where positive 

identification was possible. In some instances, a sample was not positively identifiable as H. cockerelli 

although it could be identified as belonging to the 

morosa group. These samples are most likely H. cockerelli based on a distinct head pattern. However, the 

small size of the insect made it difficult to definitively 

determine the species. When positive identification of 

species was not possible, Hydropsyche spp. was used.

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 and depuration chambers were used for the 

tributary stations. Biota samples were collected along 

an increasing concentration gradient to minimize 

effects from station-to-station carryover contamination.

Quality assurance of analytical results for biota 

samples included laboratory instrument calibration 

with standard solutions and analyses of quality-control 

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

standard reference material 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 25 percent of 

complete (100 percent) recovery for all trace metals. A 

slight low bias is indicated for all constituents (confidence interval does not include 100 percent), except for 

chromium, which showed a high bias; however, no 

adjustments were made to trace-element concentrations for insect samples on the basis of recovery efficiency because mean recoveries were within 25 percent 

for all constituents.

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 

and zinc, most 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 1985. The 

summaries include the period of record, number of 

samples, maximum, minimum, mean, and median of 

concentrations.

Statistical summaries of water-quality data (table 

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

period of record. They do not include supplemental 

single-vertical samples collected by a contract observer 

at Clark Fork at Turah Bridge and Clark Fork above 

Missoula during 1997. Statistical summaries of bedsediment (table 22 and 23) and biological data (table 

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

stations were sampled for bed sediment and biota every 

year, 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

12 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
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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tributary inflows on the distribution of trace metals in 

fine-grained sediment and benthic insects of the Clark 

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

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

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Knapton, J.R., 1985, Field guidelines for collection, treatment, and analysis of water samples, Montana District: 

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308, 55 p.

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D.A., 1994, Water-quality, bed-sediment, and biological data (October 1992 through September 1993) and 

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14 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
DATA

DATA 15
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997

[Abbreviations: ft3/s, cubic feet per second; °C, degrees Celsius; e, estimated; ug/L, micrograms per liter; jiS/cm, microsiemens per centimeter at 25 °C; 

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

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

Date

Dec 1996

09...

Mar 1997

03...

20...

Apr

21...

May

05...

Jun

04...

25...

Aug

04...

Streamflow, Specific _H ___ . Temper- Hardness, 0-1-1,, 

instan- conduct- 7 , j jf ature, total ,! t^t 

Time taneous ance, onsite ^Jf-Hrfi water (mg/L as /^M

C

ff3/e\ /nC/s*m\ UnllSJ /Os*\ Oa/^rt \ \"*9'^/ II /&) mo/Ginj \ \+) \*o\s\J$)

1200 6.0 412 7.4 4.0 140 36

0845 5.3 309 7.7 3.0 120 35

1450 156 116 7.7 2.0 38 11

1115 24 206 7.6 4.0 80 23

1110 31 214 7.8 6.5 85 25

0915 23 207 7.8 11.5 80 23

1015 29 208 7.8 9.0 85 24

1000 14 280 7.8 14.0 110 32

Magnesium, 

dissolved

(mg/L)

11

8.5

2.7

5.5

5.8

5.3

5.9

7.6

Arsenic, 

total 

recoverable (ng/L)

3

2

18

7

7

11

8

9

Date

Dec 1996

09...

Mar 1997

03...

20...

Apr

21...

May

05...

Jun

04...

25...

Aug

04...

Arsenic, C-JjJ""' Cadmium, C°PPfr' Copper, gj| 

 "rtT1 recoverable dl"J"7«« recoverable "'WT1 recoverable ing/"-) (^g/L) mg/i-j ^g/L) ing/M (Mg/L)

2 <1 <0.1 4 2 470

1 <1 <.l 3 <10 390

10 <1 <.l 25 9 4,200

4 <1 <.l 7 4 1,100

4 <1 <.l 9 5 930

7 <l <.l 9 6 900

7 <1 <.l 6 4 760

6 <1 .143 570

Iron, 

dissolved

4)

66

220

430

360

330

440

230

Lead, 

total 

recoverable (ng/L)

2

<1

14

2

1

i

<1

<1

Date

Dec 1996

09...

Mar 1997

03...

20...

Apr

21...

May

05...

Jun

04...

25...

Aug

04...

Manga- Man^a 7lnt* 7inf* 

. lnclll(]cl- £.1111*, 4*nii*, e^k^jiMn^k*** Lead, nese, ««^L tntai ^i<.<.ni..<»i oeoiment, 

dissolved total j,"68,6' ^ total ^, dissolved suspended aissuivea 10101 dissolved recoverable (i^g/L) /ma/Li

<0.5 60 57 10 4 11

<.5 60 44 <10 5 5

.6 240 100 40 5 139

<.5 50 28 <10 <3 11

<.5 40 26 <10 <3 17

<.5 60 38 <10 4 12

<.5 40 31 <10 <3 6

<.5 30 22 <10 <3 3

Sediment 

discharge, 

suspended 

(ton/d)

0.18

.07

59

.71

1.4

.75

.47

.11

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

96

93

68

86

76

71

82

86

16 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued) 

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

Date

Dec 1996 

09...

Mar 1997

03...

20...

Apr

21...

May

05...

Jun

04...

25...

Aug

04...

Time tank's

1345 23

1035 22

1320 134

1245 42

1245 40

1100 41

1140 46

1140 31

Specific T«««« 

onduct- pH, onsite T®mp.f 

ance, (standard JJJJJ®

uS/cm) ( ^

597 7.4 6.5

522 7.5 5.0

226 7.2 3.0

425 7.3 6.5

418 7.2 9.5

416 7.4 13.0

409 7.5 11.5

520 7.6 15.0

total 

(mg/L as

180

160

66

140

140

140

140

180

Calcium, 

dissolved

49

45

19

39

40

41

40

50

Magnesium, 

dissolved 

(mg/L)

13

12

4.5

9.2

10

9.9

9.7

13

Arsenic, 

total 

recoverable

13

14

45

il

10

12

11

11

Date

Dec 1996

09...

Mar 1997

03...

20...

Apr

21...

May

05...

Jun

04...

25...

Aug

04...

Arsenic, CadQmaum' 

?SQ/L) recoverable

6 4

4 3

9 4

5 6

5 3

5 5

5 5

5 6

Cadmium, ^JSSf1

"FUS* recoverable

(^a/L) (ng/L)

3 220

3 300

1 370

5 300

3 190

5 430

4 200

5 180

Copper, 

dissolved (Mg/L)

120

160

120

250

130

300

110

98

Iron, 

total 

recoverable (Mg/L)

700

740

5,900

900

820

860

690

530

Iron, 

dissolved (Mg/L)

110

100

210

200

180

180

97

26

Lead, 

total 

recoverable

(Mg/L)

4

13

130

6

4

10

5

8

Date

Dec 1996

09...

Mar 1997

03...

20...

Apr

21...

May

05...

Jun

04...

25...

Aug

04...

MangaLead, nese, 

dissolved total 

(ng/L) recoverable 

(Mg/L)

<0.5 680

<.5 760

1.9 840

.8 880

<.5 600

1 .6 990

<.5 770

.6 990

Manga- Zinc, 

nese, total 

dissolved recoverable

(ng/L) (M9/L)

720 1,300

730 1,200

410 980

880 1,600

620 980

960 1,500

750 1,300

1,000 1,800

Zinc, 

dissolved (Mg/L)

1,200

1,000

490

1,500

940

1,500

1,200

1,800

Sediment, 

suspended

(mg/L)

9

11

194

12

11

11

15

6

Sediment 

discharge, 

suspended 

(ton/d)

0.56

.65

70

1.4

1.2

1.2

1.9

.50

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

83

86

76

88

91

90

50

91

TABLE 4 17
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

12323600--SILVER BOW CREEK AT OPPORTUNITY, MONT.

Date

Dec 1996

09...

Mar 1997

04...

20...

Apr

21...

May

06...

Jun

04...

25...

Aug

04...

^Int ,!!0*' coSucf- pH.onsite Temper- HaSss' Calcium, 

Time taneous ance> (standard aturej water (mg/L as dissolved

1515 47 501 8.2 1.5

1000 44 493 8.1 0.0

0620 361 202 7.6 0.0

1405 103 308 7.7 8.0

0915 126 269 7.6 6.0

1305 296 218 8.1 11.0

1310 148 300 8.2 11.5

1330 59 448 8.8 17.0

160 45

170 50

60 18

110 33

100 30

86 26

110 34

170 49

Magnesium, 

dissolved 

(mg/L)

11

11

3.4

7.2

6.3

5.0

7.0

11

Arsenic, 

total 

recoverable

16

19

230

27

27

22

18

17

Date

Dec 1996

09...

Mar 1997

04...

20...

Apr

21...

May

06...

Jun

04...

25...

Aug

04...

Arsenic, Ca<}of' Cadmium, C°P,PJr'

difS^/'|Vfd recoverable ""f^ST1 recoverable

^9/L> (^g/L) <^/L> (ng/L)

6 3 2 160

8 3 2 200

14 12 2 1,900

9 3 2 220

9 2 1 180

11 2 1 160

9 2 1 130

8 3 2 190

*»____, Iron, 

copper, Joja|

dlfSJ?/iV\ recoverable

<K9/L> (ng/L)

39 910

46 1,100

160 24,000

68 1,700

59 1,800

51 2,600

53 1,000

54 630

Iron, 

dissolved (ng/L)

13

10

310

54

110

120

67

16

Lead, 

total 

recoverable (ng/L)

21

23

650

42

45

32

17

14

Date

Dec 1996

09...

Mar 1997

04...

20...

Apr

21...

May

06...

Jun

04...

25...

Aug

04...

"IS?- Mnans|a- {ft 

d1SST rec^j-able "^ »ff»

<0.5 620 590 760

<.5 730 690 910

5.1 2,000 690 2,300

.7 570 480 720

1.0 420 320 500

1.5 340 240 390

.5 470 400 500

<.5 880 840 790

Hiezj"cj , Sediment, 

f n/if^ suspended 

f^1-) (mg/L)

520 20

660 27

580 801

430 66

310 61

180 109

330 38

210 10

Sediment 

discharge, 

suspended 

(ton/d)

2.5

3.2

781

18

21

87

15

1.6

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

79

84

65

63

61

37

48

86

18 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

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

Date

Dec 1996

09...

Mar 1997

04...

Apr

21...

May

06...

17...

Jun

01...

23...

Aug

08...

St insTafnOW' SSK- pH, onsite Temper- Hafflss' Calcium, 

Time taneous ance' (standard atured water (my/fas dissolved

1615

1115

1555

1100

0815

0830

1220

1645

81 545 8.3 2.0 240 68

69 568 8.6 2.0 240 70

210 386 8.6 8.5 150 45

307 353 8.7 8.0 140 41

634 300 8.9 12.0 120 35

662 265 8.9 13.0 110 34

527 290 9.3 12.5 130 39

135 384 9.0 21.0 160 46

Magnesium, 

dissolved 

(mg/L)

16

16

9.4

8.8

6.8

5.9

6.6

11

Arsenic, 

total 

recoverable fog/L)

18

18

37

41

53

49

34

41

Date

Dec 1996

09...

Mar 1997

04...

Apr

21...

May

06...

17...

Jun

01...

23...

Aug

08...

Arsenic, 

dissolved fog/L)

14

14

28

30

38

38

29

39

Cadmium, r<.Hminm Copper, < »«.» «», lron> total Cadm urn, t££, C°PPer' tota iwiai dissolved wioi dissolved »wi«i recoverable 7 «/i \ recoverable 7 «/i \ recoverable

fog/L) (^9/L) fog/L) (^/L> fog/L)

<1 <0.1 12 6 280

<1 .2 24 11 300

<1 <.l 24 11 570

<1 .1 25 13 480

<1 <.l 19 14 840

<1 <.l 29 17 380

<1 .1 33 17 310

<1 <.l 12 8 150

Iron, 

dissolved fog/L)

6

7

24

24

50

34

27

15

Lead, 

total 

recoverable fog/L)

2

2

4

4

5

3

4

1

Date

Dec 1996

09...

Mar 1997

04...

Apr

21...

May

06...

17...

Jun

01...

23...

Aug

08...

Lead, 

dissolved fog/L)

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

HJ tat a JSed ---a «&. -jssy- «5sr <>*L> -rar

120 100 40 23 6

280 240 110 33 5

120 23 50 6 19

110 12 40 <3 22

100 39 30 <3 37

80 41 30 7 17

100 41 50 4 11

70 37 10 <3 7

Sediment 

discharge, 

suspended 

(ton/d)

1.3

.93

11

18

63

30

16

2.6

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

87

87

88

80

80

78

43

44

TABLE 4 19
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

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

Date

Dec 1996

09...

Apr 1997

21...

May

17...

Jun

01...

23...

Aug

08...

Streamflow, SSSX. DH onsite Tfemner- Hardness, inetan COMUUCl" prl, OnSllc IGHlpCr" »/\#al

711116 taneous ance> (standard ature^ water (mg/L as

1645 e54 347 8.3 3.0 170

1515 64 356 8.3 7.5 170

0945 280 173 8.2 7.0 80

0945 420 139 7.9 7.0 72

1300 275 191 8.3 9.0 91

1730 128 257 8.5 16.0 120

Calcium, 

dissolved

51

51

25

22

28

37

Magnesium, 

dissolved 

(mg/L)

10

11

4.2

3.9

5.1

6.8

Arsenic, 

total 

recoverable

5

6

17

27

8

7

Date

Dec 1996

09...

Apr 1997

21...

May

17...

Jun

01...

23...

Aug

08...

Arsenic, ^SJSaP' Cadmium, ^fiST Copper, 

/ , » recoverable (ua/L) recoverable fuo/L)

5 <1 <0.1 11 3

5 <1 <.l 10 2

4 <1 <.l 82 7

11 <1 <.l 97 14

6 <1 <.l 25 4

6 <1 <.l 11 4

Iron, 

recoverable

170

160

1,700

1,300

360

130

Iron, 

dissolved

6

3

26

29

10

11

Lead, 

total 

recoverable

<l

<1

9

9

2

1

Date

Dec 1996

09...

Apr 1997

21...

May

17...

Jun

01...

23...

Aug

08...

IOOH "SlSr Manga- Zinc, Zinc, 

Hi«S»H 725' nes«- total dissolved ?ua/L) reco!erable dissolved recoverable (Mg/L) 

( Mg/L) ^J^/L) 6 (M9/L) (M9/D

<0.5 240 210 <10 <3

<.5 270 220 <10 <3

<.5 300 66 40 8

<.5 170 43 30 <3

<.5 110 62 10 5

<.5 90 77 <10 4

Sediment, 

suspended 

(mg/L)

9

9

100

77

22

10

Sediment 

discharge, 

suspended 

(ton/d)

el.3

1.6

76

87

16

3.5

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

75

83

75

77

65

55

20 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

12323800--CLARK FORK NEAR GALEN, MONT.

Date

Dec 1996 

10...

Mar 1997

04...

Apr

21...

May

06...

17...

Jun

01...

23...

Aug

08...

Streamflow, ' 

T, instannme tangous

0810 136

1210 109

1705 251

1 140 342

1040 907

1035 1,050

1050 809

1845 248

:onduct- pH.onsite Temper- ^tnEfi88' Calcium, 

ance, (standard ature, water (mg/L as dissolved

486 8.0 1.5 210 59

511 8.4 1.5 230 66

383 8.6 8.0 160 47

357 8.5 9.0 150 43

266 8.7 10.5 110 33

237 8.7 12.0 100 31

265 9.0 11.0 120 36

329 8.8 19.0 140 43

Magnesium, 

dissolved 

(mg/L)

14

15

10

9.2

6.2

5.5

6.3

8.7

Arsenic, 

total 

recoverable (ng/L)

12

11

31

37

47

41

28

25

Date

Dec 1996

10...

Mar 1997

04...

Apr

21...

May

06...

17...

Jun

01...

23...

Aug

08...

Arsenic, Cado m'

 "SSST °;*able 

^ (ng/L)

10 <1

8 <1

25 <1

27 <1

27 <1

26 <1

21 <1

24 <1

Cadmium, ^fiST' Copper, 1 ; 

d'(S/L)ed recoverable 6l**$\j* recoverable

<0.1 12 5 240

.1 21 8 270

<.l 26 9 560

<1 38 12 710

<.l 92 15 1,500

.1 64 21 770

<.l 38 13 400

<1 11 7 150

Iron, 

dissolved (ng/L)

5

<3

14

15

39

30

22

12

Lead, 

total 

recoverable (ng/L)

i

2

4

6

10

6

4

1

Date

Dec 1996

10...

Mar 1997

04...

Apr

21...

May

06...

17...

Jun

01...

23...

Aug

08...

MangaLead, nese, 

dissolved total 

(ng/L) recoverable

<0.5 170

<.5 310

<.5 160

<.5 210

<.5 270

<.5 120

<.5 110

<.5 80

Manga- Zinc, Zinc, ooHiman* 

nese, total dissolved ^l",;!!^ 

dissolved recoverable (ng/L) (mg/L)

130 30 13 6

270 80 31 7

58 50 9 23

31 50 5 26

41 80 3 74

39 50 12 43

50 40 8 30

44 <10 <3 6

Sediment 

discharge, 

suspended 

(ton/d)

2.2

2.1

16

24

181

122

66

4.0

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

78

88

80

72

65

62

41

78

TABLE 4 21
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

12324200--CLARK FORK AT DEER LODGE, MONT.

Date

Dec 1996

10...

Mar 1997

04...

Apr

21...

May

06...

17...

Jun

01...

23...

Aug

09...

^BIS1 "* %£!£. PH,onsite Temper- Ha±jss' Calcium, 

Time taneous ance> (standard aturej water (mg/L as dissolved

0925 302 503 8.1 1.5 210 62

1345 233 511 8.3 3.0 230 67

1810 437 425 8.3 9.0 180 53

1335 532 403 8.2 10.0 170 50

1230 1,080 285 8.2 13.0 120 35

1215 1,260 286 8.1 12.5 120 36

1430 1,170 296 8.5 12.5 130 40

0640 313 395 8.3 14.0 180 53

Magne- Arsenic, 

sium, total 

dissolved recoverable 

(mg/L) (ng/L)

14 15

15 12

12 30

11 32

6.7 70

6.8 44

7.5 37

11 27

Date

Dec 1996

10...

Mar 1997

04...

Apr

21...

May

06...

17...

Jun

01...

23...

Aug

09...

A»A«i^ Cadmium, r-aH«i,,m Copper, r*nnno, lr°n > Arsenic, tota| Cadmium, to*£| Copper, totaj

<"fs°/'i\ed recoverable <"fs«/iV?d recoverable fs«/i \ recoverable

<ng/L> (ng/L) IWI'L' (ng/L) ^9/L; (ng/L)

11 <1 <0.l 36 5 660

8 <1 <.l 23 5 360

16 <1 <.l 75 11 1,100

20 <1 <.l 60 12 930

22 1 .1 300 30 4,300

22 <1 .2 130 32 1,600

21 <1 .1 92 18 1,100

24 <1 <.l 47 10 470

Iron, read,

""reST1 referable 

<^/L> (HQ/L)

10 4

<3 3

11 9

11 7

37 40

30 15

21 11

11 5

Date

Dec 1996

10...

Mar 1997

04...

Apr

21...

May

06...

17...

Jun

01...

23...

Aug

09...

Lead, "eT ^ gg 6£^ Sediment, 

dissolved total dissolved recoSLrable tSX) suspended 

(^g/L) racJ2/L)bto TS/D (S (m9/L)

<0.5 120 40 50 11 33

<.5 100 63 40 19 16

<.5 160 24 70 6 68

<.5 170 15 60 6 52

<.5 430 34 230 13 295

<.5 190 34 110 23 113

<.5 160 55 80 8 65

<.5 90 30 40 10 20

c<»HimAnt Sediment, SSSSS. "SSSSf

«SSjk finlrTan (ton/d) 0 062 mm)

27 70

10 71

80 59

75 54

860 46

384 50

205 56

17 77

22 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON, MONT.

Date

Dec 1996 

10...

Apr 1997

23...

May

13...

Jun

01...

23...

Aug

09...

StKn°W' 2SS PH,onsite Temper- Hirdn.-, Calcium, 

Time tarSous anc.e' (standard aturej water (nSS a8 dissolved

<ft/s> Sm) Un' S Cac°3) (m9/

1125 64 279 8.4 2.0 120 36

0905 416 211 8.2 3.5 94 27

1100 854 157 8.0 9.0 69 20

1405 1,040 179 8.1 13.0 80 23

1640 361 220 8.2 12.5 100 29

0850 126 278 8.2 11.5 130 38

Magnesium, 

dissolved

(mg/L)

X4

64

4.6

5.4

6.9

8.5

Arsenic, 

total 

recoverable (Mg/L)

4

6

11

9

7

7

Date

Dec 1996

10...

Apr 1997

23...

May

13...

Jun

01...

23...

Aug

09...

Arsenic, Cafi2i m> Cadmium, C°P^fr' Copper, | j

d'f^Lfd recoverable dlf^jT1 recoverable ^fe* recoverable

<^/L> (ng/L) <^/L) (Mg/L) (^/L) (ng/L)

4 <1 <0.1 2 <1 90

4 <1 <.l 3 2 710

5 <1 <.l 7 3 3,000

6 <1 <.l 5 3 1,200

5 <1 <.l 2 <1 180

6 <1 <.l <1 1 180

Iron, 

dissolved

5

91

110

67

26

16

Lead, 

total 

recoverable 

(MO/L)

<1

2

7

3

<1

<1

Date

Dec 1996

10...

Apr 1997

23...

May

13...

Jun

01...

23...

Aug

09...

Load "MM* Manga- Zinc, Zinc, sediment Lead, nese, noco tntal HieeoluaH oeulmenl,

dissolved total di«oived recoverable fua/U suspended (Mg/D <"**;*$»* d &Td TSB (mg/L)

<0.5 20 6 <10 <3 3

<.5 50 6 <10 <3 34

<.5 150 11 30 3 190

<.5 60 13 <10 <3 85

<.5 30 15 <10 <3 7

<.5 30 12 <10 <3 6

Sediment 

discharge, 

suspended 

(ton/d)

0.52

38

438

239

6.8

2.0

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

88

68

53

53

76

86

TABLE 4 23
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

12324680--CLARK FORK AT GOLDCREEK. MONT.

Date

Dec 1996 

10...

Mar 1997

04...

Apr

23...

May

06...

17...

Jun

01...

23...

Aug

09...

Streamflow, .

W

1235 441

1535 356

1015 894

1515 1,150

1410 2,820

1530 3,120

0915 1,950

1015 612

jonduct- pH.onsite Temper- HaSl^ss' 

ance, (standard ature, water (ma/Las

461 8.5 2.0 210

462 8.7 3.0 210

349 8.3 6.0 150

312 8.2 9.5 130

207 8.1 11.5 86

233 8.1 13.5 99

294 8.3 11.0 130

378 8.4 13.5 170

Calcium, 

dissolved

59

61

44

39

26

30

39

51

Magnesium, 

dissolved 

(mg/L)

14

14

9.8

8.4

5.1

6.0

7.7

11

Arsenic, 

total 

recoverable

14

9

17

20

43

32

30

20

Date

Dec 1996

10...

Mar 1997

04...

Apr

23...

May

06...

17...

Jun

01...

23...

Aug

09...

Arsenic, total '

Hicenli/oH luiai uiaoirivcu recoverable

(ng/L) ^g/L)

7 <1

8 <1

11 <l

12 <l

15 <1

15 <1

20 <l

17 <1

Cadmium, totaf' Copper, 

/ _/i \ recoverable / _, \

luy/Ll / .I \ lug/Li \^» / (ng/L) lf*»

<0.1 35 5

<.l 16 4

<. 1 44 7

<J 48 9

<.l 200 17

<1 110 18

.2 78 14

<. 1 29 9

Iron, 

total 

recoverable (ng/L)

590

240

1,000

1,200

5,000

3,100

1,000

420

Iron, 

dissolved

6

<3

28

36

66

47

23

13

Lead, 

total 

recoverable

4

2

6

8

36

16

8

3

Date

Dec 1996

10...

Mar 1997

04...

Apr

23...

May

06...

17...

Jun

01...

23...

Aug

09...

MangaLead, nese, 

dissolved total 

(ng/L) recoverable

<0.5 110

<.5 60

<5 120

<5 150

<.5 390

<.5 230

<5 130

<.5 70

Manga- Zinc, Zinc, 

nese, total dissolved 

dissolved recoverable (ng/L) 

(ng/L) (ng/L)

25 50 <3

32 30 12

11 50 <3

10 50 4

19 190 19

23 110 8

40 70 12

20 30 9

(mg/L)

28

10

57

68

367

219

54

20

Sediment 

discharge, 

suspended 

(ton/d)

33

9.6

138

211

2,790

1,840

284

33

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

81

84

66

62

48

51

63

81

24 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

12331500--FLINT CREEK NEAR DRUMMOND, MONT.

Date

Dec 1996

10...

Mar 1997

05...

Apr

23...

May

06...

17...

Jun

01...

23...

Aug

09...

St insSn- W> SSK- PH,onsite Temper- **$£* 

Time tano«ne ance- (standard ature, water , lo)f ' lan^ous onsite units) ( C) irng/L as

1405 140 314 8.5 1.0 150

0820 136 311 8.4 .5 150

1140 362 209 8.2 5.5 92

1700 366 215 8.2 8.5 98

1540 700 134 8.2 12.0 59

1645 722 166 8.1 12.0 74

0740 484 230 8.3 9.5 110

1145 99 363 8.6 13.5 170

Calcium, 

dissolved 

(mg/L)

39

40

24

26

16

20

31

46

Magnesium, 

dissolved 

(mg/L)

12

13

7.5

77

4.4

5.6

8.4

14

Arsenic, 

total 

recoverable (pg/L)

10

9

17

24

28

29

23

14

Date

Dec 1996

10...

Mar 1997

05...

Apr

23...

May

06...

17...

Jun

01...

23...

Aug

09...

Arsenic, CafQmlVm> Cadmium, c°PPfr' Copper,

difS£ned recoverable difs£tfd recoverable difs±ed

<^/L> (ng/L) <^/L> (ng/L) <^/L>

6 <1 <0.1 3 <1

5 <1 <.l 2 <1

6 <1 <.l 9 4

6 <1 <.l 7 2

8 <1 <.l 11 4

13 <1 <.l 11 3

14 <1 <.l 4 <1

13 <1 <.l 3 1

Iron, 

total 

recoverable (ng/L)

310

220

1,500

1,400

1,600

1,400

530

310

Iron, 

dissolved

19

<3

140

130

110

59

31

12

Lead, 

total 

recoverable

(pg/D

4

3

12

16

21

24

9

3

Date

Dec 1996

10...

Mar 1997

05...

Apr

23...

May

06...

17...

Jun

01...

23...

Aug

09...

la*./* ^fJIi8" Manga- Zinc, Zinc, 

dissolved total' nese' total dissolved 

d !Sffd recoverable dgjjj* ^Sf 6 (^g/L) 

(l^g/L)

<0.5 80 23 10 <3

<.5 60 20 10 8

<.5 210 14 40 <3

<.5 260 20 50 <3

.7 320 29 60 4

.7 340 42 50 5

<.5 180 46 30 <3

<.5 90 41 10 <3

Sediment, 

suspended 

(mg/L)

15

12

103

97

113

121

35

17

Sediment 

discharge, 

suspended 

(ton/d)

5.7

4.4

101

96

214

236

46

4.5

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

86

82

82

68

62

59

69

87

TABLE 4 25
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

12331800--CLARK FORK NEAR DRUMMOND, MONT.

Date

Dec 1996 

10...

Mar 1997

05...

Apr

23...

May

07...

17...

Jun

01...

22...

Aug

11...

StlE!ltanOW' conduct- pH,onslte Temper- HaS2iil Calcium, 

Time taniSus ance> (standard aturej water (nig/Las dissolved

1520

0955

1300

0820

1715

1810

1315

1510

663 465

584 473

1,410 340

1,620 323

3,480 226

3,860 252

2,890 309

716 431

8.3 3.0 210

8.3 2.5 210

8.2 7.5 150

8.1 8.0 140

8.1 14.0 94

8.1 15.0 110

8.2 13.5 140

8.4 18.0 200

59

61

43

40

28

32

41

57

Magnesium, 

dissolved 

(mg/L)

14

15

II

9.3

5.9

6.8

8.8

14

Arsenic, 

total 

recoverable

13

II

18

25

49

38

30

16

Date

Dec 1996

10...

Mar 1997

05...

Apr

23...

May

07...

17...

Jun

01...

22...

Aug

11...

Arsenic, 

dissolved (ng/L)

7

9

9

10

15

19

20

15

Cadmium, ^-H^III . tntal v/aamium,

recoverable ff?/i\ 

(Mg/L) <^/L>

<1 <0.1

<1 <.l

<l <1

<1 <.l

1 <.l

<1 <.l

<1 .1

<1 <1

C2£T Copper, 

recoverable *-*£«' 

(MO/L) (M9/L)

33 4

21 4

50 7

67 8

220 17

150 18

77 12

16 6

Iron, 

total 

recoverable (ng/L)

660

450

1,500

1,900

5,300

3,500

1,400

230

Iron, 

dissolved

5

<3

68

57

60

42

21

3

Lead, 

total 

recoverable

5

3

9

13

36

25

10

2

Date

Dec 1996

10...

Mar 1997

05...

Apr

23...

May

07...

17...

Jun

01...

22...

Aug

11...

Lead, 

dissolved (Mg/L)

<0.5

<.5

<.5

<.5

<5

<5

<.5

<5

"S3T ^fl8-

total H8S8, 

dissolved recoverable /.Tn/i \ 

(Mg/L) ^9/L>

120 18

70 25

160 11

230 11

500 27

340 31

170 48

50 16

Zinc, Zinc, 

total dissolved 

recoverable (ng/L)

50 5

40 11

70 <3

100 6

290 12

180 11

90 4

20 <3

Sediment, 

suspended 

(mg/L)

36

22

96

111

356

238

91

13

Sediment 

discharge, 

suspended 

(ton/d)

64

35

365

485

3,340

2,480

710

25

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

81

79

65

65

64

63

60

82

26 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

12334510--ROCK CREEK NEAR CLINTON, MONT.

Date

Dec 1996 

11...

Apr 1997

22...

May

19...

Jun

02...

22...

Aug

11...

Stros inflow opocim* Hsrdnoss 

Time taifeous ance> (standard ature^ water (mg/Las dissolved 

(fr/s) (MS/cm) CaCO3)

1545 284 133 8.1 1.5 59 15

1445 1,140 93 7.9 6.5 40 10

1030 4,940 55 7.7 5.5 22 5.9

0730 5,060 59 7.7 8.5 25 6.6

1130 2,260 82 7.9 9.5 38 9.9

1340 435 128 8.3 15.5 59 16

Magnesium, 

dissolved 

(mg/L)

5.2

3.5

1.9

2.1

3.1

4.9

Arsenic, 

total 

recoverable

(ng/L)

3

<1

2

2

<1

<1

Date

Dec 1 996

11...

Apr 1997

22...

May

19...

Jun

02...

22...

Aug

11...

Arsenic, Cadmaum' Cadmium, <*PPfr' Copper, gj 

"oSST1 recoverable * $ * recoverable <"JJJ* recoVe'rabie

<1 <1 <0.1 <1 <1 40

<1 <1 <.l 2 <1 390

1 <1 <.l 3 1 1,200

1 <1 <.l 3 1 1,200

<1 <1 <.l 2 <1 220

<1 <1 <.l <1 <1 60

iron, 

dissolved

(ng/U

10

160

98

83

44

16

Lead, 

total 

recoverable

<[

<i

i

l

<l

<i

Date

Dec 1996

11...

Apr 1997

22...

May

19...

Jun

02...

22...

Aug

11...

i«»^ ^llli8" Manga- Zinc, Zinc, c^im^r,* Lead, nese, _. " ioifl,' HI««O|U«»H Sediment, _ii»»_.i..__i *.«.»«ki nose, loiai QissoivGu ^.I^MMAM^IM^J disr .jsru. -J3J7- "°x$r -wsr

<0.5 <10 <1 30 <3 2

<.5 <10 2 <10 <3 14

<.5 40 4 <10 <3 117

<.5 40 4 <10 <3 223

<.5 10 4 <10 <3 17

<.5 <10 3 <10 <3 2

Sediment 

discharge, 

suspended 

(ton/d)

1.5

43

1,560

3,050

104

2.3

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

73

69

66

39

61

67

TABLE 4 27
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued) 

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

Date

Dec 1996

11...

Mar 1997

05...

Apr

22...

May

07...

'13...

'14...

'15...

'16...

'18...

'19...

19...

'20...

'21...

'22...

'23...

Jim

'01...

'02...

02...

'03...

'04...

22...

Jul

'01...

'03...

'07...

'11...

'15...

'17...

'19...

Aug

11...

Time

1345

1140

1130

1100

1600

1030

1045

1300

0800

0925

1320

1415

1215

1030

0945

1730

0945

0950

1440

0940

1540

1515

1105

0615

1025

0940

0830

1030

1210

Streamflow, 

Instantaneous 

(ft3/s)

987

845

3,150

3,840

6,660

6,420

7,500

8,480

8,940

8,910

8,880

8,180

7,760

7,700

7,530

9,410

9,650

9,560

9,030

8,620

5,670

4,140

4,120

2,880

2,430

1,870

1,790

1,970

1,160

Specific 

conductance, 

onsite 

(jiS/cm)

374

392

234

213

156

163

149

143

136

143

140

152

153

151

150

156

160

160

168

175

225

244

258

265

272

283

282

275

329

pH, onsite 

(standard 

units)

8.5

8.4

8.1

7.9

8.0

7.9

7.8

7.9

7.9

8.0

8.0

7.9

7.9

7.9

8.1

8.1

8.1

8.1

8.0

8.1

8.2

8.3

8.2

8.2

8.3

8.2

8.2

8.3

8.4

Temperature, water (dC)

2.0

3.0

7.0

8.5

13.0

13.0

11.0

15.0

9.0

9.0

9.0

13.0

12.0

12.0

11.0

15.0

13.0

11.0

14.0

12.0

13.5

13.0

13.0

15.0

13.0

16.0

17.0

16.0

16.0

Hardness, 

total 

(mg/L as 

CaC03)

170

180

98

92

68

72

65

62

58

60

58

65

65

64

64

66

67

67

72

72

100

100

110

110

120

120

120

120

150

Calcium, 

dissolved 

(mg/L)

4i

50

27

26

19

20

19

18

17

17

17

19

19

18

18

19

19

19

21

21

29

30

32

33

34

35

36

35

42

Magnesium, 

dissolved 

(mg/L)

12

13

7.3

6.7

4.8

5.1

4.5

4.2

3.9

4.1

3.9

4.4

4.4

4.4

4.3

4.4

4.5

4.6

4.8

4.8

6.8

7.0

7.5

7.7

8.0

8.3

8.6

8.3

11

Arsenic, 

total 

recoverable

(M9/L)

7

7

li

12

19

18

20

22

23

21

20

17

14

13

12

18

20

22

18

16

18

13

15

13

11

10

10

11

10

28 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued) 

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

Date

Dec 1996

11...

Mar 1997

05...

Apr

22...

May

07...

'13...

'14...

'15...

'16...

'18...

'19...

19...

'20...

'21...

'22...

'23...

Jun

'01...

'02...

02...

'03...

'04...

22...

Jul

'01...

'03...

'07...

Ml...

'15...

'17...

'19...

Aug

11...

Arsenic, 

dissolved (MQ/L)

5

6

5

6

7

7

7

8

8

8

8

8

7

8

6

7

9

8

9

8

13

8

11

10

10

9

9

9

10

Cadmium, cadmium, C°PPfr' 

total rticfnhiati total 

recoverable [JSu recoverable

(n9/L) *"" ' (M9/L)

<1 <0. 1 14

<1 . <.l 10

<1 <.l 36

<1 <.l 37

<1 <.l 93

<1 <.l 73

<1 <.l 92

<1 <.l 99

<1 <.l 110

<1 <.l 92

<1 <.l 85

<1 <.l 66

<1 <.l 49

<1 <1 42

<1 .1 48

<1 <.l 87

<1 <.l 100

<1 <.l 86

<1 <.l 70

<1 <.) 57

<1 .1 43

<1 .1 26

<1 <.l 25

<1 <.l 18

<1 <.l 13

<1 <.l 13

<1 <.l 13

<1 <.l 16

<1 <.l 9

Copper, 

dissolved 

(MQ/L)

4

3

6

5

13

10

12

20

13

13

12

11

10

10

10

11

13

12

13

12

9

9

10

7

6

10

6

6

4

Iron, 

total 

recoverable (MO/L)

270

190

1,600

1,400

3,100

2,900

3,700

4,000

4,300

3,500

3,000

2,200

1,700

1,600

1,400

2,900

3,400

2,900

1,900

1,500

960

750

680

420

290

240

200

310

160

Iron, 

dissolved

5

<3

94

74

91

79

75

95

120

110

76

82

67

50

49

50

71

69

40

37

25

12

14

11

9

7

4

8

5

Lead, 

total 

recoverable

2

1

7

7

16

14

18

20

21

16

14

11

9

8

7

15

17

i5

10

9

6

4

4

3

2

2

2

2

1

TABLE 4 29
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued) 

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

Date

Dec 1996

11...

Mar 1997

05...

Apr

22...

May

07...

'13...

'14...

'15...

'16...

'18...

'19...

19...

'20...

'21...

'22...

'23...

Jun

'01...

'02...

02...

'03...

'04...

22...

Jul

'01...

'03...

'07...

Ml...

M5...

M7...

'19...

Aug

11...

MangaLead, nese, 

dissolved total 

(ng/L) recoverable

(M9/L)

<0.5 60

<.5 30

<5 140

<.5 130

<.5 280

<.5 270

<.5 340

<.5 410

<.5 390

<.5 370

<.5 260

<.5 200

<.5 160

<.5 150

<.5 130

<.5 270

.8 330

<.5 270

<.5 190

<.5 160

<5 120

<.5 90

<.5 80

<.5 60

<5 50

<.5 40

<.5 40

<.5 50

<.5 30

Manganese, 

dissolved (ng/L)

4

10

7

11

3

3

2

3

4

5

16

7

13

3

1

7

9

19

3

3

37

<1

1

6

<1

<1

<1

<1

9

Zinc, 

total 

recoverable

20

20

60

60

150

130

180

200

210

180

150

110

90

80

70

150

180

150

110

90

60

40

40

30

20

20

20

20

10

Zinc, 

dissolved

(M9/L)

<3

12

<3

5

5

7

8

10

6

4

9

9

10

7

6

6

4

6

6

9

7

<3

<3

<3

5

5

3

12

7

Sediment, 

suspended 

(mg/L)

16

8

86

99

442

332

348

411

315

244

207

169

126

128

108

328

326

244

202

151

64

44

38

26

18

14

10

18

8

Sediment 

discharge, 

suspended 

(ton/d)

43

18

731

1,030

7,950

5,750

7,050

9,410

7,600

5,870

4,960

3,730

2,640

2,660

2,200

8,330

8,490

6,300

4,920

3,510

980

492

423

202

118

71

48

96

25

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

87

87

67

52

-

-

-

-

--

66

..

~

~

--

-

-

60

-

-

67

-

-

-

-

--

--

--

83

30 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

12340000-BLACKFOOT RIVER NEAR BONNER, MONT.

Date

Dec 1996

11...

May 1997

19...

Jun

02...

22...

Aug

11...

St iS5n°W> 2B2* PH,onsite Temper- Har£ ,ss' Calcium, 

Time tanAnus ance> (standard ature, water /Jn/i «« dissolved 

(frVs) onsite unlts) ( C) CaCO ) (mg/L)

1120 701 258 8.5 1.0 130 33

1945 13,400 150 8.3 9.0 72 19

1155 11,800 147 8.3 10.0 72 19

0935 5,130 179 8.4 11.5 91 24

0920 1,160 258 8.4 14.5 130 33

Magnesium, 

dissolved 

(mg/L)

12

5.9

5.8

7.7

12

Arsenic, 

total 

recoverable 

<HO/L)

<l

3

2

<1

1

Date

Dec 1996

11...

May 1997

19...

Jun

02...

22...

Aug

11...

Arsenic, ^f' Cadmium, c°PPfr' Copper, 'r°"j 

dWL?d recoverable ^gf recoverable ^f 1 recoverable

(}jg/L) (^g/L) (^g/L)

<l <l <0.l 1 <l 50

1 <1 <.l 8 2 1,900

1 <1 <.l 34 2 1,300

1 <1 <.l 3 <1 330

1 <1 <.l <1 <1 60

Iron, 

dissolved

(ng/ )

3

43

47

13

4

Lead, 

total 

recoverable (ng/L)

<i

3

2

<1

<1

Date

Dec 1996

11...

May 1997

19...

Jun

02...

22...

Aug

11...

Lead, T2T Mna"9a- Z!"C,' diSad Sediment, 

dissolved total JSSSnd recoverable fuiyL) suspended (ng/L) recoverable fv/n recoverame (ngii.) (mg/L) 

(Mg/L) ^9/LJ ^g/L'

<0.5 <10 <1 <10 <3 2

<5 110 6 <10 <3 212

<5 80 4 <10 <3 157

<5 30 4 <10 <3 23

<.5 <10 1 <10 <3 3

Sediment 

discharge, 

suspended

(ton/d)

3.8

7,670

4.990

319

9.4

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

83

68

67

84

93

TABLE 4 31
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

12340500--CLARK FORK ABOVE MISSOULA, MONT.

Date

Dec 1996

11...

Mar 1997

05...

Apr

22...

May

07...

'13...

'14...

'15...

'16...

'18...

'19...

20...

'20...

'21...

'22...

'23...

Jun

'01...

'02...

02...

'03...

'04...

22...

Jul

'01...

'03...

'07...

'11...

'15...

'17,.

'19...

Aug

11...

Time

0930

1415

0900

1445

1700

1145

1150

1415

0930

1045

0715

1505

1300

1125

1055

1820

1030

1345

1545

1030

1740

1615

1210

0710

1145

1040

1030

1130

1040

Streamflow, instantaneous 

(fp/s)

1,700

1,450

8,680

10,800

17,000

17,500

20,900

23,600

26,700

24,200

21,600

20,600

18,900

17,700

17,300

20,400

21,100

21,100

19,000

18,200

10,100

7,940

7,730

6,210

5,340

4,330

3,980

4,220

2,470

Specific 

conductance, 

onsite

(US/Cm)

323

330

196

181

150

154

147

147

141

147

154

157

157

155

154

150

152

153

157

161

204

219

232

235

243

253

254

253

293

pH, onsite 

(standard 

units)

8.3

8.4

8.0

8.0

8.0

8.0

7.8

8.0

8.2

8.1

8.1

8.0

7.9

7.9

8.2

8.1

8.2

8.2

8.1

8.2

8.3

8.3

8.2

8.2

8.3

8.2

8.3

8.3

8.5

Temperature, water (dC)

1.0

2.5

6.0

8.0

12.0

12.0

11.0

13.0

9.0

9.0

9.5

13.0

11.0

12.0

12.0

13.0

13.0

11.5

15.0

12.0

14.0

13.0

13.0

15.0

15.0

18.0

17.0

17.0

16.0

Hardness, 

total 

(mg/L as 

CaC03)

150

150

89

84

71

73

69

69

67

69

69

72

73

71

72

69

70

70

73

75

96

99

100

110

110

120

120

120

140

Calcium, 

dissolved 

(mg/L)

41

42

24

22

19

20

19

19

19

19

19

20

20

19

20

19

19

19

20

21

26

27

29

29

30

32

32

32

38

Magnesium, 

dissolved 

(mg/L)

12

12

7.2

6.7

5.5

5.6

5.2

5.1

5.0

5.2

5.3

5.5

5.6

5.5

5.5

5.2

5.2

5.3

5.4

5.6

7.3

7.4

7.8

8.0

8.3

8.8

9.1

8.8

11

Arsenic, 

total 

recoverable (ng/L)

4

4

5

5

10

8

10

14

14

12

to

9

8

7

6

8

10

11

9

7

9

7

9

7

7

8

7

6

7

32 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

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

Date

Dec 1996

11...

Mar 1997

05...

Apr

22...

May

07...

'13...

'14...

'15...

'16...

'18...

'19...

20...

'20...

'21...

'22...

'23...

Jun

'01...

'02...

02...

'03...

'04...

22...

Jul

'01...

'03...

'07...

'11...

'15...

'17...

'19...

Aug

11...

Arsenic, 

dissolved

(H9/L)

3

4

3

3

4

4

4

4

4

4

4

4

4

4

3

3

4

4

5

4

7

6

6

6

6

5

6

5

6

Cadmium, r*0.im\. m Copper, t«t«.i Cadmium, »J»§!»i total dissolved total recoverable r.Tn/n recoverable

(H9/L) (^g/L) (ng/L)

< 1 <0. 1 6

<1 <. 1 7

<1 <.l 14

<1 <.l 20

<1 <.l 47

<1 <.l 37

<1 <.l 42

<1 <.l 62

<1 <.l 63

<1 <.l 53

<1 <.l 50

<1 <.l 36

<1 <.l 30

<1 <.l 24

<1 <.l 23

<1 <.l 39

<1 <.l 45

<1 <.l 49

<1 <.l 38

<1 .1 27

<1 <.l 22

<1 <.l 22

<1 <.l 20

<1 <.l 15

<1 <.l 19

<1 <.l 23

<1 <.l 23

<1 <.l 9

<1 <.l 6

Copper, 

dissolved

(H9/L)

2

2.

3

4

5

5

5

7

6

6

6

6

5

6

6

8

7

7

7

7

4

7

7

4

4

4

4

4

3

Iron, 

total 

recoverable

(H9/L)

130

170

990

800

2,900

2,100

3,500

4,700

5,000

3,700

3,000

2,200

1,600

1,400

1,300

2,000

2,200

2,200

1,500

1,200

560

400

450

300

430

500

400

160

100

Iron, 

dissolved

<3

<3

110

59

61

64

73

76

71

77

65

44

54

41

39

45

53

44

32

30

17

10

11

5

4

<3

<3

<3

7

Lead, 

total 

recoverable

(H9/L)

<l

1

3

3

10

7

10

13

14

11

9

7

5

4

4

7

9

9

6

5

3

3

2

2

2

3

3

1

<1

TABLE 4 33
Table 4. Water-quality data for the upper Clark Fork basin, Montana, October 1996 through September 1997 (Continued)

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

Date

Dec 1 996

11...

Mar 1997

05...

Apr

22...

May

07...

'13...

'14...

'15...

'16...

'18...

'19...

20...

'20...

'21...

'22...

'23...

Jun

'01...

'02...

02...

'03...

'04...

22...

Jul

'01...

'03...

'07...

'11...

'15...

'17...

'19...

Aug

11...

Lead, 

dissolved (Mg/L)

<0.5

<5

<5

<.5

<.5

<5

<5

<5

<.5

<.5

<.5

<.5

<5

<.5

<.5

<5

<5

<5

<5

<5

<.5

<5

<5

<.5

<.5

<5

<.5

<.5

<5

Manganese, 

total 

recoverable

(M9/L)

30

30

80

70

220

170

250

300

320

260

180

160

130

110

90

140

170

190

120

100

70

50

50

40

50

60

40

30

30

Manganese, 

dissolved

(Mg/U

12

19

11

16

5

3

2

3

3

8

15

6

11

3

1

5

9

17

4

3

24

<1

<1

5

1

<1

<1

<1

20

Zinc, 

total 

recoverable (ng/L)

10

20

30

20

100

60

100

120

130

120

90

70

60

50

40

60

80

80

60

50

30

20

30

20

30

40

30

10

<10

Zinc, 

dissolved

(ng/D

<3

3

<3

<3

3

<3

<3

<3

<3

4

4

5

<3

8

7

4

8

5

<3

8

<3

<3

<3

4

<3

3

5

<3

7

Sediment, 

suspended 

(mg/L)

6

8

61

54

182

272

360

436

518

338

260

212

146

124

106

173

182

187

129

97

37

22

26

18

29

42

34

14

4

Sediment 

discharge, 

suspended 

(ton/d)

28

31

1,430

1,570

8,350

12,900

20,300

27,800

37,300

22,100

15,200

11,800

7,450

5,930

4,950

9,530

10,400

10,700

6,620

4,770

1,010

472

543

302

418

491

365

160

27

Sediment, 

suspended 

(percent 

finer than 

0.062 mm)

87

95

85

80

-

-

--

--

--

--

52

--

--

-

--

-

--

66

--

-

78

--

-

--

--

--

--

--

93

'Supplemental sampling to better define chemical changes during extended high-water runoff, and the lowering of Milltown Reservoir levels for dam structure maintenance.

34 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1996 through 

September 1997

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

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/s)

189

183

181

176

175

172

176

179

183

188

197

206

207

206

206

209

210

215

225

240

240

241

254

264

258

254

252

258

266

274

262

6,746

218

274

172

Suspended sediment

Mean 

concentration 

(mg/L)

October

15

19

22

23

21

18

15

12

21

32

29

25

22

18

14

11

11

12

12

13

13

14

18

24

23

21

19

18

19

19

21

...

19

32

11

Discharge 

(ton/d)

7.7

9.4

11

11

9.9

8.4

7.1

5.8

10

16

15

14

12

10

7.8

6.2

6.2

7.0

7.3

8.4

8.4

9.1

12

17

16

14

13

13

14

14

15

335.7

11

17

5.8

Mean 

streamflow 

(tf/s)

264

272

274

280

283

281

283

288

293

291

282

278

278

285

279

256

243

264

278

339

299

307

300

280

295

287

275

293

298

275

...

8,500

283

339

243

Suspended sediment

Mean 

concentration 

(mg/L)

1996

November

25

24

21

20

19

19

19

19

21

22

21

18

16

15

15

14

14

14

15

28

31

31

29

22

19

19

19

20

21

21

...

...

20

31

14

Discharge 

(ton/d)

18

18

16

15

15

14

15

15

17

17

16

14

12

12

11

9.7

9.2

10

11

26

25

26

23

17

15

15

14

16

17

16

...

474.9

16

26

9.2

Mean 

streamflow 

(tf/s)

289

270

253

246

254

257

254

276

328

311

310

295

279

284

264

276

230

214

236

241

e230

e220

e200

e!90

e!80

el 70

e!70

e200

254

512

653

8,346

269

653

170

Suspended sediment

Mean 

concentration 

(mg/L)

December

21

20

19

18

19

20

24

28

34

38

55

45

35

27

23

22

22

24

30

25

18

12

10

10

10

10

12

14

16

479

760

...

61

760

10

Discharge 

(ton/d)

16

15

13

12

13

14

16

21

30

32

46

36

26

21

16

16

14

14

19

16

11

7.1

5.4

5.1

4.9

4.6

5.5

7.6

11

662

1340

2,470.2

80

1,340

4.6

TABLE 5 35
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1996 through 

September 1997 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow

(ft3/s)

1,040

766

565

484

432

359

363

350

336

323

e250

e!90

el 70

e!60

e!70

e!90

e220

285

328

316

308

322

288

271

e250

e240

e230

249

243

299

424

10,421

336

1,040

160

Suspended sediment

Mean 

concentration 

(mg/L)

January

785

235

110

70

45

35

30

28

26

25

23

20

18

16

17

25

32

35

33

28

22

18

19

20

21

22

22

22

21

29

39

...

61

785

16

Discharge 

(ton/d)

2,200

486

168

91

52

34

29

26

24

22

16

10

8.3

6.9

7.8

13

19

27

29

24

18

16

15

15

14

14

14

15

14

23

45

3,496.0

113

2,200

6.9

Mean 

streamflow 

(ft3/s)

393

361

312

271

e230

e220

e210

235

235

232

245

260

264

269

280

325

321

295

290

279

274

274

267

259

262

265

249

235

...

...

...

7,612

272

393

210

Suspended sediment

Mean 

concentration 

(mg/L)

1997

February

33

31

28

26

23

20

18

17

17

23

30

31

31

31

31

31

31

31

30

29

26

23

22

21

20

19

17

15

...

...

...

...

25

33

15

Discharge 

(ton/d)

35

30

24

19

14

12

10

11

11

14

20

22

22

23

23

27

27

25

23

22

19

17

16

15

14

14

11

9.5

...

...

...

529.5

19

35

9.5

Mean 

streamflow

(ft3/s)

240

235

235

237

232

236

244

246

229

245

258

278

279

269

274

321

372

364

414

431

445

503

492

453

373

352

349

341

319

321

324

9,911

320

503

229

Suspended sediment

Mean 

concentration 

(mg/L)

March

15

17

21

18

20

19

24

33

17

20

49

39

27

18

39

107

303

111

163

174

136

180

111

84

59

52

43

40

33

30

32

...

66

303

15

Discharge 

(ton/d)

9.7

11

13

12

13

12

16

22

11

13

34

29

20

13

29

93

304

109

182

202

163

244

147

103

59

49

41

37

28

26

28

2,072.7

67

304

9.7

36 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1996 through 

September 1997 (Continued)

Day

l

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

M1N

Mean 

streamflow 

(ft3/s)

324

328

330

322

297

304

323

312

308

294

286

298

299

294

293

305

311

334

364

414

436

434

434

500

490

481

480

506

524

544

...

11,169

372

544

286

Suspended sediment

Mean 

concentration 

(mg/L)

April

28

29

29

23

29

32

27

25

23

25

28

31

31

20

26

24

35

34

46

75

73

66

60

115

79

67

60

61

94

77

...

...

46

115

20

Discharge 

(ton/d)

24

26

26

20

23

26

24

21

19

20

22

25

25

16

21

20

29

31

45

84

86

77

70

155

105

87

78

83

133

113

...

1,534

51

155

16

Mean 

streamflow 

(fr'/s)

563

576

545

510

509

534

615

600

614

623

684

736

775

836

888

957

1,070

1,130

1,140

1,040

989

965

956

1,040

1,270

1,270

1,170

1,050

1,040

1,120

1,190

27,005

871

1,270

509

Suspended sediment

Mean 

concentration 

(mg/L)

1997

May

88

86

68

59

54

91

100

95

73

77

126

169

172

172

239

251

286

219

166

135

113

98

96

108

152

121

81

75

74

86

96

...

123

286

54

Discharge 

(ton/d)

134

134

100

81

74

131

166

154

121

130

233

336

360

388

573

649

826

668

511

379

302

255

248

303

521

415

256

213

208

260

308

9,437

304

826

74

Mean 

streamflow 

(ft3/s)

1,260

1,370

1,360

1,360

1,430

1,660

1,770

1,880

1,900

1,830

1,860

1,950

1,900

1,980

1,860

1,740

1,680

1,670

1,640

1,530

1,390

1,250

1,150

1,070

1,000

919

818

774

737

765

...

43,503

1,450

1,980

737

Suspended sediment

Mean 

concentration

(mg/L)

June

108

116

93

82

86

97

101

93

82

73

67

77

79

86

59

57

60

59

55

53

53

58

64

60

59

57

55

49

41

41

...

...

71

116

41

Discharge 

(ton/d)

367

429

341

301

332

435

483

472

421

361

336

405

405

4hO

296

268

272

266

244

219

199

196

199

173

159

141

121

102

82

85

...

8,570

286

483

82

TABLE 5 37
Table 5. Daily streamflow and suspended-sediment data for Clark Fork at Deer Lodge, Montana, October 1996 through 

September 1997 (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

(fl3/s)

994

963

900

841

772

759

722

632

586

566

559

521

486

443

384

334

335

354

394

715

582

515

468

432

399

375

354

338

335

337

342

16,737

540

994

334

Suspended sediment

Mean 

concentration 

(mg/L)

July

83

47

35

32

29

28

27

26

26

25

24

22

21

20

19

19

19

19

23

173

36

23

20

19

19

19

19

19

20

18

16

--

30

173

16

Discharge 

(ton/d)

223

122

85

73

60

57

53

44

41

38

36

31

28

24

20

17

17

18

24

334

57

32

25

22

20

19

18

17

18

16

15

1,604

52

334

15

Mean 

streamflow

(ft3/s)

381

408

382

330

370

418

382

354

317

308

300

292

284

288

264

320

348

367

399

357

360

350

333

323

322

325

337

329

315

298

295

10,456

337

418

264

Suspended sediment

Mean 

concentration 

(mg/L)

1997

August

20

22

23

23

23

26

24

17

20

17

14

11

10

10

10

15

17

17

18

14

12

11

11

10

10

10

17

10

9

8

7

--

15

26

7

Discharge 

(ton/d)

21

24

24

20

23

29

25

16

17

14

11

8.7

7.7

7.8

7.1

13

16

17

19

13

12

10

9.9

8.7

8.7

8.8

15

8.9

7.7

6.4

5.6

435.0

14

29

5.6

Mean 

streamflow

(ft3/s)

292

285

283

305

294

297

292

291

287

277

283

305

313

317

316

330

329

323

317

324

337

338

334

310

294

288

295

300

297

291

--

9,144

305

338

277

Suspended sediment

Mean 

concentration 

(mg/L)

September

8

8

9

9

9

9

8

8

7

7

7

7

7

8

8

9

8

8

8

7

8

8

9

10

10

10

10

10

10

10

--

--

8

10

7

Discharge 

(ton/d)

6.3

6.2

6.9

7.4

7.1

7.2

6.3

6.3

5.4

5.2

5.3

5.8

5.9

6.8

6.8

8.0

7.1

7.0

6.8

6.1

7.3

7.3

8.1

8.4

7.9

7.8

8.0

8.1

8.0

7.9

--

208.7

7.0

8.4

5.2

TOTAL FOR WATER YEAR 1997:

STREAMFLOW--169,550 ft3/s 

SEDIMENT DISCHARGE-31,167.7 tons

38 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1996 

through September 1997

[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

M1N

Mean 

streamflow

(fl3/s)

905

879

871

873

864

849

855

856

849

853

872

873

872

883

909

920

921

921

940

937

925

914

932

940

933

931

924

915

930

935

913

27,894

900

940

849

Suspended sediment

Mean 

concentration 

(mg/L)

October

11

10

9

8

8

8

7

7

7

7

7

7

9

9

9

8

8

8

7

7

7

8

9

9

10

10

10

9

9

9

8

...

8

11

7

Discharge 

(ton/d)

27

24

21

19

19

18

16

16

16

16

16

16

21

21

22

20

20

20

18

18

17

20

23

23

25

25

25

22

23

23

20

630

20

27

16

Mean 

streamflow

(fl3/s)

884

897

909

915

920

916

913

918

916

914

909

907

904

911

914

862

798

844

929

937

985

917

937

860

900

923

888

901

926

894

...

27,148

905

985

798

Suspended sediment

Mean 

concentration 

(mg/L)

1996

November

8

7

7

7

6

6

6

6

6

6

7

7

6

6

6

6

6

5

6

6

7

6

14

13

14

14

10

10

12

11

...

...

8

14

5

Discharge

(ton/d)

19

17

17

17

15

15

15

15

15

15

17

17

15

15

15

14

13

11

15

15

19

15

35

30

34

35

24

24

30

27

...

580

19

35

11

Mean 

streamflow 

(ft3/s)

867

891

846

807

814

836

830

860

944

999

987

960

897

852

858

861

781

e650

e680

e720

e750

e660

e540

e580

e590

e450

e400

e640

e800

el, 000

el, 500

24,850

802

1,500

400

Suspended sediment

Mean 

concentration 

(mg/L)

December

7

7

7

8

9

9

8

6

5

16

17

12

9

8

8

8

8

8

12

11

7

4

4

4

4

4

4

4

5

34

81

...

11

81

4

Discharge 

(ton/d)

16

17

16

17

20

20

18

14

13

43

45

31

22

18

19

19

17

14

22

21

14

7.1

5.8

6.3

6.4

4.9

4.3

6.9

11

92

328

908.7

29

328

4.3

TABLE 6 39
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1996 

through September 1997 (Continued)

Day

1

2

3

4

5

6

1

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

M1N

Mean 

streamflow 

(ft3/s)

2,080

3,230

2,360

1,860

1,600

1,330

1,240

1,260

1,210

1,210

1,130

e800

e600

e520

e540

e580

e700

e800

el, 000

el, 050

el, 040

el, 040

el, 000

e950

e950

e850

e800

e800

e900

el, 000

el, 200

35,630

1,149

3,230

520

Suspended sediment

Mean 

concentration 

(mg/L)

January

114

490

277

100

62

52

44

39

37

36

34

32

32

34

36

37

38

39

40

41

42

40

33

22

16

17

19

21

23

25

35

62

490

16

Discharge 

(ton/d)

640

4,270

1,770

502

268

187

147

133

121

118

104

69

52

48

52

58

72

84

108

116

118

112

89

56

41

39

41

45

56

68

113

9,697

313

4,270

39

Mean 

streamflow

(ft3/s)

1,300

1,340

1,250

1,050

e850

e800

e750

e700

e750

e800

e850

e900

918

910

936

985

1,010

1,030

1,020

998

959

951

937

918

888

909

915

885

-

26,509

947

1,340

700

Suspended sediment

Mean 

concentration 

(mg/L)

1997

February

53

46

35

25

24

24

23

22

22

22

22

22

18

12

18

28

33

37

38

38

36

32

29

28

27

25

22

18

...

...

--.

28

53

12

Discharge 

(ton/d)

186

166

118

71

55

52

47

42

45

48

50

53

45

29

45

74

90

103

105

102

93

82

73

69

65

61

54

43

...

...

...

2,066

74

186

29

Mean 

streamflow

(ft3/s)

858

876

862

845

840

835

846

876

878

902

972

1,020

999

913

889

952

1,310

1,590

2,060

2,740

2,860

2,720

2,620

2,470

2,350

2,510

3,070

2,790

2,460

2,280

2,250

50,443

1,627

3,070

835

Suspended sediment

Mean 

concentration 

(mg/L)

March

13

13

12

9

9

9

9

10

11

13

20

28

29

18

11

16

105

169

380

468

320

107

121

80

69

86

180

80

44

41

39

...

81

468

9

Discharge 

(ton/d)

30

31

28

21

20

20

21

24

26

32

52

77

78

44

26

41

371

726

2.110

3,460

2,470

786

856

534

438

583

1,490

603

292

252

237

15,779

509

3,460

20

40 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1996 

through September 1997 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/s)

2,130

2,000

1,950

1,910

1,810

1,700

1,690

1,680

1,620

1,560

1,430

1,400

1,420

1,450

1,510

1,580

1,760

2,050

2,270

2,760

3,190

3,130

3,010

3,110

3,110

3,050

3,150

3,420

3,470

3,360

67,680

2,256

3,470

1,400

Suspended sediment

Mean 

concentration 

(mg/L)

April

32

29

28

26

22

18

20

20

17

15

15

15

13

14

15

14

22

41

55

106

130

90

72

66

70

60

65

94

81

62

...

...

44

130

13

Discharge 

(ton/d)

184

157

147

134

108

83

91

91

74

63

58

57

50

55

61

60

105

227

337

790

1,120

761

585

554

588

494

553

868

759

562

...

9,776

326

1,120

50

Mean 

streamflow 

(tt3/s)

3,300

3,140

3,050

3,050

3,210

3,450

3,790

3,790

3,760

4,100

4,880

5,370

5,800

6,640

7,500

8,340

8,680

8,920

8,910

8,180

7,760

7.700

7,610

7,960

8,840

8,910

8,300

7,700

7,580

8,070

8,420

196,710

6,345

8,920

3,050

Suspended sediment

Mean 

concentration 

(mg/L)

1997

May

51

45

39

37

41

56

97

103

84

132

222

257

316

318

326

370

335

307

220

154

122

116

99

117

192

182

116

97

97

121

189

...

160

370

37

Discharge 

(ton/d)

454

382

321

305

355

522

993

1,050

853

1,460

2,930

3,730

4,950

5,700

6,600

8,330

7,850

7,390

5,290

3,400

2,560

2,410

2,030

2,510

4,580

4,380

2,600

2,020

1,990

2,640

4,300

94,885

3,060

8,330

305

Mean 

streamflow 

(tt3/s)

8,930

9,530

9,060

8,710

8,870

9,060

8,590

8,540

8,800

8,060

8,050

8,280

8.220

8,450

8,430

8,150

7,720

7,760

7,460

6,640

6,210

5,700

5,270

4,940

4.580

4,210

3,820

3,450

3,330

3,870

...

212,690

7,090

9,530

3,330

Suspended sediment

Mean 

concentration 

(mg/L)

June

239

248

|7)

130

147

147

114

132

143

110

106

144

120

133

134

149

124

93

111

96

73

61

48

45

42

39

37

34

34

43

...

...

108

248

34

Discharge 

(ton/d)

5,760

6,380

4,180

3,060

3,520

3,600

2,640

3,040

3,400

2,390

2,300

3,220

2,660

3,030

3,050

3,280

2,580

1,950

2,240

1,720

1,220

939

683

600

519

443

382

317

306

449

...

69,858

2,330

6,380

306

TABLE 6 41
Table 6. Daily streamflow and suspended-sediment data for Clark Fork at Turah Bridge, near Bonner, Montana, October 1996 

through September 1997 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/s)

4,050

4,470

4,080

3,670

3,250

3,010

2,870

2,660

2,500

2,480

2,430

2,320

2,180

2,080

1,970

1,870

1,790

1,870

2,010

2,290

2,400

2,160

1,990

1,860

1,780

1,680

1,620

1.570

1,530

1.500

1,430

73,370

2,367

4,470

1,430

Suspended sediment

Mean 

concentration 

(mg/L)

July

43

66

40

32

34

27

25

21

20

20

18

18

15

14

13

10

10

17

24

53

59

32

20

17

15

15

14

14

13

13

12

24

66

10

Discharge 

(ton/d)

470

797

441

317

298

219

194

151

135

134

118

113

88

79

69

50

48

86

130

328

382

187

107

85

72

68

61

59

54

53

46

5,439

175

797

46

Mean 

streamflow

(ft3/s)

1,390

1,400

1,400

1,340

1,270

1,290

1,320

1,360

1,270

1,190

1.160

1,110

1,070

1,050

1,050

1,030

1,130

1,150

1,140

1,140

1,110

1,110

1,070

1,070

1,060

1.050

1,020

1,020

1,020

989

962

35,741

1,153

1,400

962

Suspended sediment

Mean 

concentration 

(mg/L)

1997

August

12

11

11

10

10

10

9

9

8

8

8

8

8

7

6

3

4

6

4

3

3

3

3

4

4

4

4

4

4

6

7

6

12

3

Discharge 

(ton/d)

45

42

42

36

34

35

32

33

27

26

25

24

23

20

17

8.3

12

19

12

9.2

9.0

9.0

8.7

12

11

11

11

11

11

16

18

649.2

21

45

8.3

Mean 

streamflow

(frVs)

946

939

955

988

988

984

965

950

943

938

e930

e970

1,010

1,030

1,060

1,110

1,120

1,120

1,100

1.090

1,090

1,090

1,090

1,090

1,090

1,070

1.110

1,130

1,120

1,110

...

31,126

1,038

1,130

930

Suspended sediment

Mean 

concentration 

(mg/L)

September

7

8

7

7

7

7

6

6

6

6

4

6

7

8

10

11

12

II

10

9

8

8

8

8

8

8

8

8

7

7

...

...

8

12

4

Discharge 

(ton/d)

18

20

18

19

19

19

16

15

15

15

10

16

19

22

29

33

36

33

30

26

24

24

24

24

24

23

24

24

21

21

...

661

22

36

10

TOTAL FOR WATER YEAR 1997:

STREAMFLOW-809,791 ft3/sec 

SEDIMENT DISCHARGE-210,929 tons

42 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1996 through 

September 1997

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

Day

Mean 

streamflow 

(ft3/s)

Suspended sediment

Mean 

concentration 

(mg/L)

October

Discharge 

(ton/d)

Suspended sediment

UAan

stream- Mean 

flow concen- 

(ft3/s) tration 

(mg/L)

1996 

November

Discharge 

(ton/d)

Suspended sediment

Uaan

stream- Mean 

flow concen- 

(ft*/s) tration 

(mg/L)

December

Discharge 

(ton/d)

l

2

3

4

5

6

7

8

9

10

II

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

1,570

1,560

1,530

1,540

1,530

1,490

1,490

1,480

1,470

1,470

1,480

1,500

1,500

1,530

1,550

1,590

1,570

1,590

1,630

1,650

1,660

1,650

1,710

1,660

1,680

1,660

1,660

1,580

1,660

1,620

1,440

48,700

1,571

1,710

1,440

5

6

6

6

5

5

5

5

5

5

6

5

4

4

4

4

4

4

4

4

5

6

6

6

7

8

8

8

8

18

10

...

6

18

4

21

25

25

25

21

20

20

20

20

20

24

20

16

17

17

17

17

17

18

18

22

27

28

27

32

36

36

34

36

79

39

794

26

79

16

1,320

1,450

1,560

1,560

1.560

1,580

1,540

1,560

1,550

1,570

1,560

1,540

1,560

1,560

1,560

1,490

1,370

1,420

1,290

1,520

1,500

1,550

1,570

1.440

1,520

1,610

1,550

1,580

1,620

1,570

...

45,630

1,521

1,620

1,290

6

6

6

6

6

8

9

8

7

5

5

5

5

5

5

5

5

4

3

3

3

3

4

4

4

4

4

5

5

5

...

...

5

9

3

21

23

25

25

25

34

37

34

29

21

21

21

21

21

21

20

18

15

10

12

12

13

17

16

16

17

17

21

22

21

...

626

21

37

10

1,540

1,560

1,500

1,400

1,380

1,470

1,460

1,480

1,650

1,710

1,720

1,660

1,520

1,490

1,490

el, 450

el, 300

el, 100

el, 150

el, 400

el, 400

el, 200

el, 050

el, 150

el, 150

e900

e900

el, 200

el, 500

el, 900

2,470

44,250

1,427

2,470

900

4

4

4

4

5

6

6

7

12

10

6

6

6

5

5

5

6

9

10

10

9

8

8

8

8

8

8

8

8

8

18

...

7

18

4

17

17

16

15

19

24

24

28

53

46

28

27

25

20

20

20

21

27

31

38

34

26

23

25

25

19

19

26

32

41

120

906

29

120

15

TABLE 7 43
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1996 through 

September 1997 (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 

(tt3/s)

3,250

4,660

3,520

2,860

2,360

2,210

2,090

2,110

2,040

2,070

el, 800

el, 300

el, 000

el, 000

el, 150

el, 400

el, 800

2,190

2,050

2.050

2,100

2,050

1,970

el,850

el, 700

el, 500

el, 300

el, 400

el, 600

1,760

1,990

62,130

2,004

4,660

1,000

Suspended sediment

Mean 

concentration 

(mg/L)

January

37

182

100

48

44

36

22

14

11

10

9

9

10

11

14

19

26

22

16

12

9

8

7

 6

6

5

6

9

14

16

17

...

24

182

5

Discharge 

(ton/d)

325

2,290

950

371

280

215

124

80

61

56

44

32

27

30

43

72

126

130

89

66

51

44

37

30

28

20

21

34

60

76

91

5,903

190

2,290

20

Mean 

streamflow

(ft3/s)

2,130

2,120

1,970

1,800

el, 600

el, 450

el, 300

el, 200

el, 300

el, 400

1,530

1,570

1,630

1,640

1,610

1,690

1,750

1,800

1,860

1,750

1,690

1,670

1,670

1,670

1,590

1,600

1,600

1,570

...

...

46,160

1,649

2,130

1,200

Suspended sediment

Mean 

concentration 

(mg/L)

1997

February

17

16

15

12

10

10

9

8

8

8

8

9

9

10

10

10

10

10

14

26

27

26

22

18

15

15

15

12

...

...

...

...

14

27

8

Discharge 

(ton/d)

98

92

80

58

43

39

32

26

28

30

33

38

40

44

43

46

47

49

70

123

123

117

99

81

64

65

65

51

...

...

...

1,724

62

123

26

Mean 

streamflow

(ft3/s)

1,530

1,550

1,540

1,490

1,470

1,460

1,470

1,520

1,540

1,600

1,730

1,760

1,840

1,610

1,500

1,630

1,990

2,290

2,790

3,950

4,310

4,310

4,380

4,230

4,190

4,470

5,680

5,620

4,910

4,580

4,470

87,410

2,820

5,680

1,460

Suspended sediment

Mean 

concentration 

(mg/L)

March

ll

8

10

8

8

10

12

8

9

9

12

15

17

11

7

9

13

33

56

127

84

61

50

39

41

45

60

58

38

28

26

...

30

127

7

Discharge 

(ton/d)

45

33

42

32

32

39

48

33

37

39

56

71

84

48

28

40

70

204

422

1,350

978

710

591

445

464

543

920

880

504

346

314

9,448

305

1,350

28

44 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1996 through 

September 1997 (Continued)

Day

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

TOTAL

MEAN

MAX

MIN

Mean 

streamflow 

(ft3/s)

4,290

3,960

3,970

3,940

3,660

3,460

3,370

3,360

3,220

3,190

2,910

2,850

2,890

3,080

3,240

3,490

4,070

5,120

5,610

6,840

8,190

8,450

8,430

8,400

8,060

8,180

8,740

9,550

9,800

9,590

...

163,910

5,464

9,800

2,850

Suspended sediment

Mean 

concentration 

(mg/L)

April

22

20

20

21

16

13

14

15

16

14

13

12

12

12

14

17

22

36

35

52

73

57

43

81

79

42

40

48

49

44

32

81

12

Discharge 

(ton/d)

255

214

214

223

158

121

127

136

139

121

102

92

94

100

122

160

242

498

530

960

1,610

1,300

979

1,840

1,720

928

944

1,240

1,300

1,140

...

17,609

587

1,840

92

Mean 

streamflow 

(ft3/s)

9,420

8,920

8,590

8,720

9,230

9,880

10,700

10,800

10,800

11,700

13,500

14,900

16,300

18,400

20,900

23,000

25,200

26,400

24,100

21,000

18,800

17,800

17,400

18,200

20,200

19,800

18,000

16,800

16,300

16,700

17,700

500,160

16,130

26,400

8,590

Suspended sediment

Mean 

concentration 

(mg/L)

1997

May

39

33

31

30

33

42

52

54

57

71

121

158

184

316

431

510

557

592

399

254

180

145

125

133

177

172

118

101

83

81

100

...

174

592

30

Discharge 

(ton/d)

992

795

719

706

822

1,120

1,500

1,570

1,660

2,240

4,410

6,360

8,100

15,700

24,300

31,700

37,900

42,200

26,000

14,400

9,140

6,970

5,870

6,540

9,650

9,200

5,730

4,580

3,650

3,650

4,780

292,954

9,450

42,200

706

Mean 

streamflow

(ft3/s)

19,600

21,000

19,400

18,300

19,800

20,600

19,100

18,000

18,000

16,700

16,700

17,500

17,100

16,600

16,300

15,700

14,800

14,300

13,800

12,600

11,300

10,300

9,590

9,080

8680

8,110

7,630

7,320

7,160

7,750

...

432,820

14,430

21,000

7,160

Suspended sediment

Mean 

concentration 

(mg/L)

June

154

183

135

105

128

168

119

107

106

95

82

95

85

75

76

68

62

56

53

48

41

38

33

29

27

25

23

20

18

24

...

...

76

183

18

Discharge 

(ton/d)

8,150

10.400

7,070

5,190

6,840

9,340

6,140

5,200

5,150

4,280

3,700

4,490

3,920

3,360

3,340

2,880

2,480

2,160

1,970

1,630

1,250

1,060

854

711

633

547

474

395

348

502

...

104,464

3,480

10,400

348

TABLE 7 45
Table 7. Daily streamflow and suspended-sediment data for Clark Fork above Missoula, Montana, October 1996 through 

September 1997 (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/*)

7,840

8,190

7,740

7,250

6,730

6,410

6,150

5,840

5,510

5,430

5,300

5,050

4,800

4,580

4,370

4,140

3,800

3,770

4,170

4,670

5,090

64,500

e4,200

e3,900

e3,700

e3,500

e3,300

e3,200

3,170

3160

3,040

152,500

4,919

8,190

3,040

Suspended sediment

Mean 

concentration 

(mg/L)

July

23

32

27

22

21

19

18

19

23

25

29

34

47

50

42

37

30

12

14

13

15

14

7

6

6

6

6

6

6

6

6

_.

20

50

6

Discharge 

(ton/d)

487

708

564

431

382

329

299

300

342

367

415

464

609

618

496

414

308

122

158

164

206

170

79

63

60

57

53

52

51

51

49

8,868

286

708

49

Mean 

streamflow 

(ft3/*)

2,940

2,920

2,880

2,870

2,660

2,650

2,690

2,690

2,620

2,520

2,460

2,400

2,470

2,290

2,230

2,250

2,370

2,,390

2,370

2,310

2,240

2,230

2,170

2,150

2,180

2,140

2,090

2,060

2,030

1,990

1,950

74,210

2394

2,940

1,950

Suspended sediment

Mean 

concentration 

(mg/L)

1997

August

5

5

5

5

5

5

5

6

6

5

4

5

7

7

7

7

6

5

5

5

5

5

5

5

5

5

5

5

5

4

4

...

5

7

4

Discharge 

(ton/d)

40

39

39

39

36

36

36

44

42

34

27

32

47

43

42

43

38

32

32

31

30

30

29

29

29

29

28

28

27

21

21

1,053

34

47

21

Mean 

streamflow

(tf/s)

1,920

1,900 i

1,930

1,940

1,950

1,950

1,920

1,860

1,830

1,830

1,820

1,830

1,870

1,900

1,950

2,060

2,090

2,080

1,990

1,950

1,940

1,920

1,900

1,890

1,870

1,880

1,920

1,900

1,900

1,900

...

57,590

1,920

2,090

1,820

Suspended sediment

Mean 

concentration 

(mg/L)

September

4

5

5

5

5

5

6

6

6

5

5

5

8

8

9

9

7

7

6

6

6

5

5

5

5

5

5

5

4

4

...

...

6

9

4

Discharge 

(ton/d)

21

26

26

26

26

26

31

30

30

25

25

25

40

41

47

50

40

39

32

32

31

26

26

26

25

25

26

26

21

21

...

891

30

50

21

TOTAL FOR WATER YEAR 1997:

STREAMFLOW--1,715,470 frVsec 

SEDIMENT DlSCHARGE-445,240 tons

46 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
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 minimum reporting level; --, no data]

Station 

number

12324200

12324590

12324680

12334550

12340500

Station name

Clark Fork at Deer Lodge

Little Blackfoot River near Garrison

Clark Fork at Goldcreek

Clark Fork at Turah Bridge, near Bonner

Clark Fork above Missoula

Date

03-04-97

03-04-97

08-09-97

08-09-97

06-23-97

06-23-97

04-23-97

04-23-97

05-07-97

05-07-97

05-19-97

05-19-97

06-02-97

06-02-97

Hard- ^a'" 

 n«« "ess total <*j'"l> 

TIme (mg/L as ^

1345

1350

0640

0645

1640

1645

1015

1020

1100

1105

1320

1325

1345

1350

230

230

180

180

100

100

150

150

92

92

58

58

70

170

67

67

53

53

29

30

44

44

26

26

17

17

19

19

Magnesium, 

dissolved 

(mg/L)

15

15

11

11

6.9

7.0

9.8

9.6

6.7

6.7

3.9

4.0

5.3

5.3

Arsenic, 

total recoverable

(Mg/L)

12

11

27

27

7

6

17

17

12

13

20

19

11

11

Station 

number

12324200

12324590

12324680

12334550

12340500

Date

03-04-97

03-04-97

08-09-97

08-09-97

06-23-97

06-23-97

04-23-97

04-23-97

05-07-97

05-07-97

05-19-97

05-19-97

06-02-97

06-02-97

Arsenic, 

dissolved

(M9/L)

8

9

24

24

5

6

11

10

6

5

8

7

4

4

Cadmium, 

total 

recoverable

(M9/L)

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

Cadmium, 

dissolved

<0.1

<.i

<.i

<.

<.

<.

<.

<.

<.

<.

<.

<.i

<.i

<.i

Copper, 

total

(M9/L)

23

22

47

47

2

2

44

49

37

40

85

86

49

49

solved

5.0

5.0

10

9.8

<1

<1

7.2

7.3

5.3

5.3

12

12

6.5

9.7

(M9/L)

360

350

470

470

180

180

1,000

1,000

1,400

1,400

3,000

2,900

2,200

2,100

Iron, 

dissolved

(M9/L)

<3

<3

11

12

26

27

28

28

74

83

76

77

44

47

Lead, 

total 

recoverable

(M9/L)

3

3

5

5

<1

<1

6

9

7

8

14

14

9

8

Station 

number

12324200

12324590

12324680

12334550

12340500

Date

03-04-97

03-04-97

08-09-97

08-09-97

06-23-97

06-23-97

04-23-97

04-23-97

05-07-97

05-07-97

05-19-97

05-19-97

06-02-97

06-02-97

Lead, 

dissolved

(M9/L)

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.S

Manganese, 

total 

recoverable

(Mg/L)

100

100

93

91

29

23

120

120

130

130

260

270

190

180

Manganese, Zn°.' Zinc, "ssr TEST di$r

63

62

30

29

15

16

11

11

11

11

16

17

17

17

40

40

40

40

<10

<10

50

50

60

60

150

160

80

90

19

20

9.9

9.0

<3

<3

<3

3.0

4.6

3.0

9.3

10

4.7

3.2

Sediment, 

suspended 

(mg/L)

16

15

20

20

7

7

57

59

99

96

207

213

187

188

Sediment, 

suspended, 

diameter, 

percent 

finer than 

0.062 mm

71

77

77

79

76

71

66

65

52

54

66

65

66

65

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

samples, upper Clark Fork basin, Montana

[Abbreviations: fig/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, 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, mg/L

Sediment, suspended, percent finer than 0.062 mm

Number of 

replicate pairs

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

7

Standard 

deviation, 

in units (+/-)

0.27

.07

.53

.60

.0

.0

1.6

.86

38

2.6

.89

.0

4.1

.53

3.8

.71

1.9

2.3

Relative 

standard 

deviation, 

in percent (+/-)

0.74

.84

3.5

6.4

.0

.0

3.8

12

3.1

6.8

14

.0

3.1

2.3

6.1

9.8

2.2

3.4

48 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
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, |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, |ig/L

Iron, dissolved, |ig/L

Lead, total recoverable, |ig/L

Lead, dissolved, |ig/L

Manganese, total recoverable, |ig/L

Manganese, dissolved, |ig/L

Zinc, total recoverable, |ig/L

Zinc, dissolved, |ig/L

Number of 

replicate pairs

11

11

11

11

11

11

11

11

11

11

11

11

11

11

11

11

Standard 

deviation, 

in units (+/-)

0.33

.08

.16

.51

.01

.02

.94

.33

20

1.7

.26

.0

1.8

2.5

1.3

6.1

Relative 

standard 

deviation, 

in percent (+/-)

1.0

1.1

1.1

4.9

1.8

6.0

1.9

1.9

1.8

1.4

5.2

.0

1.0

2.8

.8

5.6

Within limits 

of dataquality 

objective

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

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

[Abbreviation: ng/L, micrograms per liter]

Constituent and reporting unit

Arsenic, total recoverable, jag/L

Arsenic, dissolved, ng/L

Cadmium, total recoverable, |xg/L

Cadmium, dissolved, |xg/L

Copper, total recoverable, |xg/L

Copper, dissolved, |xg/L

Iron, total recoverable, |xg/L

Iron, dissolved, |xg/L

Lead, total recoverable, ng/L

Lead, dissolved, |ig/L

Manganese, total recoverable, |xg/L

Manganese, dissolved, |xg/L

Zinc, total recoverable, |xg/L

Zinc, dissolved, |xg/L

Number of 

samples

3

3

3

3

3

3

3

3

3

3

3

3

3

3

95-percent 

confidence 

interval for 

spike recovery, 

in percent

104-108

87.8-100

77.7-93.7

92.1-105

82.0-131

86.2-116

78.5-111

80.2-112

88.9-113

93.4-109

82.7-97.9

95.8-103

86.4-99.0

78.1-118

Mean spike 

recovery, 

in percent

106.1

93.9

85.7

98.5

106.4

101.1

94.7

96.1

101.1

101.0

90.3

99.3

92.7

97.9

Within limits 

of dataquality 

objective

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

50 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

Montana

[Abbreviation: ug/L, micrograms per liter]

Constituent and reporting unit Number of samples

95-percent 

confidence interval 

for spike recovery,

in percent

Mean spike 

recovery, 

in percent

Within limits of

data-quality

objective

Arsenic, total recoverable, 

Arsenic, dissolved, ^g/L 

Cadmium, total recoverable, 

Cadmium, dissolved, |*g/L 

Copper, total recoverable, 

Copper, dissolved, ug/ 

Iron, total recoverable, 

Iron, dissolved, |*g/L 

Lead, total recoverable, 

Lead, dissolved, ng/L 

Manganese, total recoverable, \ig/L 

Manganese, dissolved, ng/L 

Zinc, total recoverable, \igfL 

Zinc, dissolved,

99.9-114

73.5-113

75.0-93.6

83.5-113

71.9-129

88.3-106

81.0-118

78.2-117

99.1-105

91.6-110

84.0-102

94.5-105

74.4-111

89.9-104

107.1

93.3

84.3

98.1

100.5

97.3

99.3

97.5

102.1

100.8

93.0

99.8

92.7

97.0

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; ^iS/cm, microsiemens per centimeter at 25 °C; mg/L, milligrams per liter. 

Symbol: <, less than minimum reporting level]

Specific H Maane- Arsenic, 

conduct- onsite Calcium, S|Jm total Dal> T1°" *££ «»*«' "Sf "to""* SS2 tSSt " » **" ""«"-' SK

Dec 1996

11.. 0830 3 5.7 <0.02 <0.01 <1

Mar 1997

04... 1800 3 5.5 <02 <01 <1

Apr

22... 1330 3 5.4 <02 <01 <1

May

18... 0600 3 5.6 .04 .01 <1

Jun

01... 1900 2 5.7 <02 <.01 <1

23... 1600 3 5.6 <.02 <01 <1

Aug

10... 1700 2 5.6 <02 <01 <1

Arsenic, »*£» Cadmium, Ogf 

dissolved recoverab,e dl««°f'«d recoverable 

<^/L> (W/L) ^/L) (M/L)

<1 <1 <0.1 <1

<1 <1 <.l <1

<1 <1 <.l <1

<1 <1 <.l <1

<1 <1 <.l <1

<1 <1 <1 <1

<1 <1 <.l <1

Iron L&fld Copper, |"J"j Iron, TTv Lead, 

Date dissolved nowunUt dissolved recoverable dissolved 

(n9/L) ((lfl/L) fog/L) ((jg/L) (ng/L) r«

Dec 1996

11.. <1 <10 <3 <1 <0.5

Mar 1997

04... <1 <10 <3 <1 <.5

Apr

22... <1 <10 <3 <1 <5

May

18... <1 <10 <3 <1 <.5

Jun

01... <1 <10 <3 <1 <5

23... <1 <10 <3 <1 <.5

Aug

10... <1 <10 <3 <1 <5

nese, Manganese, f"f,' Zinc, 

total dissolved ^^ dissolved 

xwerable (ng/L) t«wwo«ia (\iglL) 

(ua/u tw1-/

<10 <1 <10 <3

<10 <1 <10 4

<10 <1 <10 <3

<10 <1 <10 <3

<10 <1 <10 <3

<10 <1 <10 3

<10 <1 <10 <3

52 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 14. Trace-element analyses of fine-grained bed sediment, upper Clark Fork basin, Montana, August 1997

[Fine-grained sediment is material less than 0.064 millimeter in diameter. 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

(«g. 1)

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340050

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Warm Springs Creek at Warm 

Springs

Clark Fork near Galen

Clark Fork below Lost Creek, 

near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek 

diversion, near Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, 

near Bonner

Clark Fork above Missoula

Clark Fork below Missoula 1

Number 

of composite 

samples

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

Concentration

Cadmium

25.5

5.3

2.6

7.6

8.4

7.5

6.9

6.0

5.5

2.4

4.3

<8

4.4

3.7

1.8

Chromium

31.0

24.3

30.8

33.9

34.5

33.3

31.1

35.7

36.8

23.9

32.6

21.4

30.3

28.5

20.9

Copper

4,810

268

848

1,540

2,050

1,610

1,550

1,500

1,080

70

747

14

635

516

192

Iron

40,600

21,700

22,400

30,900

31,400

29,800

30,200

31,000

28,600

23,400

24,500

17,200

23,000

21,800

17,500

Lead

788

61

86

152

190

153

152

159

118

178

105

<10

85

63

27

, in \aglg

Manganese

1,840

1,670

2,020

2,780

3,540

2,680

2,630

1,630

1,840

2,360

1,560

618

1,700

1,160

1,270

Nickel

16.2

12.5

17.6

18.2

18.7

16.5

15.8

17.6

17.8

11.7

15.7

11.6

16.2

14.5

11.8

Silver

16.4

2.1

3.7

5.3

7.0

6.0

6.2

5.9

4.8

7.5

4.7

.4

3.9

2.9

1.7

Zinc

7,130

639

372

1,160

1,460

1,190

1,260

1,140

1,070

648

1,000

45

1,050

924

437

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

TABLE 14 53
Table 15. Trace-element analyses of bulk bed sediment, upper Clark Fork basin, Montana, August 1997

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

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

Station number

(«g. 1)

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340500

12353000

Station name

Silver Bow Creek at Opportunity

Silver Bow Creek at Warm Springs

Warm Springs Creek at Warm 

Springs

Clark Fork near Galen

Clark Fork below Lost Creek, 

near Galen

Clark Fork near Racetrack

Clark Fork at Dempsey Creek 

diversion, near Racetrack

Clark Fork at Deer Lodge

Clark Fork at Goldcreek

Flint Creek near Drummond

Clark Fork near Drummond

Rock Creek near Clinton

Clark Fork at Turah Bridge, 

near Bonner

Clark Fork above Missoula

Clark Fork below Missoula1

Number 

of com- . 

posite 

samples

l

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Concentration, in ng/g

Cadmium

5.4

1.3

<.8

1.9

3.1

1.9

1.8

2.9

4.4

.9

3.4

<.8

1.6

<.8

<.8

Chromium

16.2

11.6

11.8

8.7

17.5

12.4

16.3

24.5

33.2

10.7

29.5

8.1

16.6

9.7

7.8

Copper

775

66

203

315

763

361

424

691

858

34

605

6

247

43

49

Iron

29,300

11,000

10,900

13,200

21,000

16,200

20,900

25,000

24,900

13,400

21,800

7,400

14,100

11,500

8,830

Lead

263

<10

18

52

104

66

58

84

86

80

78

<10

35

7

<10

Manganese

504

209

1,220

899

1,260

759

825

1,020

1,570

2,240

1,510

186

347

228

403

Nickel

6.0

5.3

5.7

5.4

8.2

5.5

5.5

10.4

15.2

5.3

14.2

5.1

10.7

8.2

6.0

Silver

4.1

1.3

1.1

1.1

2.8

1.9

2.0

2.8

3.7

5.8

3.5

.3

1.5

.6

.4

Zinc

1,720

157

146

417

787

472

448

777

927

332

911

16

508

145

121

'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 1996 through September 1997) 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: ug/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 of 10.0 ug/g for lead]

Constituent

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Number of 

measurements

10

10

10

10

10

10

10

10

10

14

14

14

14

14

14

14

14

14

Dilution ratio

1:5

1:5

1:5

1:5

1:5

1:5

1:5

1:1

1:5

1:10

1:10

1:10

1:10

1:10

1:10

1:10

1:1

1:10

Certified 

concentration

(ng/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)

296

64.0

98.5

82.7

--

82.7

81.6

301

88.8

101

60.6

103

83.1

101

81.4

80.7

106

93.5

95-percent confidence 

interval for SRM 

recovery 

(percent)

287-306

60.7-67.3

92.6-104

81.2-84.2

--

81.5-83.9

80.5-82.7

287-315

86.2-91.4

98.1-103

55.8-65.4

95.9-110

78.8-87.4

98.6-104

79.3-83.5

77.7-83.7

99.0-114

90.9-96.1

TABLE 16 55
Table 17. Trace-element analyses of procedural blanks for bed sediment

[Abbreviation: ug/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; , no data]

Sample 

identification

A

A

A

B

B

B

C

C

C

D

D

D

E

E

E

F

F

F

G

G

G

H

H

H

I

I

I

J

J

J

Dilution 

ratio

1:1

1:5

1:10

1:1

1:5

1:10

1:1

1:5

1:10

1:1

1:5

1:10

1:1

1:5

1:10

1:1

1:5

1:10

1:1

1:5

1:10

1:1

1:5

1:10

1:1

1:5

1:10

1:1

1:5

1:10

Trace-element concentration, in ug/mL

Cadmium

..

<0.005

<.005

_

<.005

<.005

_

<.005

<.005

__

<.005

<.005

__

<.005

<.005

_

<.005

<.005

_

<.005

<.005

<.005

<.005

_

<.005

<.005

_

<.005

<.005

Chromium

<0.005

<.005

__

<.005

<.005

__

<,005

<.005

<.005

<.005

~

<.005

<.005

__

<.005

<.005

._

<.005

<.005

<.005

<.005

._

<.005

<.005

_

<.005

<.005

tr «»

_.

<0.011 0.057

<.011 .031

_.

<.011 <.015

<.011 .016

<.011 .022

<.011 .036

<.011 .023

<.011 .022

<.011 <.015

<.011 <.015

__

<.011 <.015

<.011 <.015

_.

<.011 .022

<.011 .308

..

<.011 .017

.014 <.015

._

<.011 .022

<.011 <.015

..

<.011 .021

<.011 <.015

Lead

<0.06

<.06

__

<.06

<.06

__

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

<.06

1.11

<.06

<.06

<.06

<.06

<.06

<.06

Manganese

<0.005

<.005

__

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

<.005

.062

__

<.005

<.005

<.005

<.005

<.005

<.005

Nickel

<0.015

<.015

__

<.015

<.015

__

<.015

<.015

<015

<.015

<015

<.015

<015

<.015

<.015

<.015

__

<015

<015

<.015

<.015

<.015

<.015

Silver Zinc

<0.011

0.005

<.005

<.011

<.005

<.005

<.011

<.005

.005

<011

<.005

.007

<011

.006

<.005

<011

<.005

<.005

<011

<.005

2.05

<.011

.010

<.005

<011

.006

<.005

<.011

.005

<.005

56 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana
Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 1997

[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]

Taxon

Brachycentrus spp.

Hydropsyche cockerelli

Hydropsyche spp. 

Hydropsyche spp.

Arctopsyche grandis

Hydropsyche cockerelli

Hydropsyche occidentalis 

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche spp.

Hydropsyche cockerelli

Hydropsyche occidentalis 

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche spp.

Arctopsyche grandis

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Number o 

composite 

samples

1

2

if Concentration, in ug/g

Cad- Chro- Cop- , 

mlum mlum per

12323600 Silver Bow Creek at Opportunity

11.6 0.7 587 335

12323750 Silver Bow Creek at Warm Springs

.6 .7 42.7 675

2 .5 .8 37.6 667 

12323770 Warm Snrines Creek at Warm Sorines

1

1

1

<9.3 1.6 94.8 1,150

2.1 1.4 95.6 1,040

12323800 Clark Fork near Galen

2.1 2.6 72.8 1,510

Lead

7.4

3.6

3.3 

<16.7

<6.3

11.0

4 1.0 2.2 101 1,700 10.2 

461415112450801 Clark Fork below Lost Creek, near Galen

1

3

1

2

2.5 2.5 141 1,840

1.7 2.3 148 1,740

1.2 1.5 122 1,410

461559112443301 Clark Fork near Racetrack

1.7 1.9 100 1,220

12.1

10.9

7.2

7.7

4 2.0 2.4 151 1,720 10.8 

461903112440701 Clark Fork at Demosev Creek diversion, near Racetrack

1

1

1

1

1

3

4

2

3

2

3

1

1

4

3

4

I

1.6 1.3 143 1,290

1.7 1.9 163 1,590

1.7 2.1 140 1,610

12324200 Clark Fork at Deer Lodge

<4.2 1.0 34.9 537

<4.9 2.1 102 1,340

1.0 2.3 152 1,750

12324680 Clark Fork at Goldcreek

1.7 2.9 108 1,980

3.2 .6 67.0 286

1.3 4.3 170 2,980

1.0 3.2 140 2,360

12331500 Flint Creek near Drummond

.3 1.2 10.7 798

<1.0 2.1 15.8 1,870

.6 2.1 18.0 1,370

12331800 Clark Fork near Drummond

3.1 1.7 63.6 1,140

2.2 .5 65.6 148

2.2 3.4 134 2,440

2.0 2.8 118 2,060

8.4

10.3

13.2

3.8

<8.9

11.8

8.9

1.4

14.7

13.8

5.6

16.2

14.6

6.8

.8

14.4

13.5

Manganese

231

506

498 

956

1,340

1,070

1,280 

1,250

1,320

799

699

1,100 

487

826

638

379

396

667

679

85.9

662

111

831

725

1,780

742

92.6

704

861

Nickel Zinc

1.0

.4

.5 

2.0

1.8

1.9

1.5 

1.2

1.6

1.4

1.3

1.5 

1.6

1.4

1.6

<1.7

.9

1.2

1.6

.3

2.1

1.7

.7

2.3

1.8

1.1

.2

1.9

1.8

888

214

167 

129

197

182

203 

250

246

179

186

250 

180

224

212

140

147

210

207

266

229

223

185

183

183

206

237

235

226

TABLE 18 57
Table 18. Trace-element analyses of biota, upper Clark Fork basin, Montana, August 1997 (Continued)

Taxon

Number of 

composite 

samples

Concentration, in jag/g

CadmiumChromiumCopper

Iron Lead

Manganese

Nickel Zinc

12334510 Rock Creek near Clinton

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche spp.

3

2

1

.4

.2

.3

1.5

.5

1.7

9.3

31.8

16.2

896

116

1,030

<2.3

<.9

<1.8

402

55.7

436

1.0

.4

1.3

131

228

117

T 2334550 Clark Fork at Turah Bridee. near Bonner

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Hydropsyche spp.

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

Arctopsyche grandis

Claassenia sabulosa

Hydropsyche cockerelli

Hydropsyche occidentalis

5

3

3

2

1

3

2

3

1

4

2

3

1

2.5

1.8

1.7

1.8

1.3

12340500

1.4

1.8

1.2

1.0

12353000

.8

1.1

.7

.7

3.1

.5

3.2

3.0

2.4

92.9

64.2

109

101

84.1

2,160

125

2,350

2,240

1,800

9.5

<1.1

11.3

11.7

<7.8

768

93.4

706

769

537

2.0

.2

1.7

1.7

1.3

243

241

218

230

171

Clark Fork above Missoula

2.2

.8

3.5

2.9

54.6

44.4

89.2

76.5

1,690

116

2,890

2,240

5.7

<2.6

6.0

7.7

724

92.9

823

939

1.5

<.6

2.2

1.9

188

250

218

210

Clark Fork below Missoula1

1.6

.5

2.3

1.7

28.6

49.7

42.1

38.2

1,170

219

1,800

1,380

2.3

.4

2.9

2.0

607

97

649

637

1.3

.2

1.4

1.2

145

205

146

144

'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 1996 through September 1997) and statistical summaries off data ffor 

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

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

95-percent confidence

Constit nt Number of Certified concentration Mean SRM recovery interval for SRM 

measurements (nfl/g) (percent) recovery

(percent)

SRM sample TORT-2

Cadmium 9 26.7 92.0 86.4-97.6

Chromium 9 .77 110 100-121

Copper 9 106 93.3 89.0-97.7

Iron 9 105 86.2 80.9-91.6

Lead 9 .35 88.4 84.7-92.0

Manganese 9 13.6 88.2 82.9-93.6

Nickel 9 2.5 76.1 71.6-80.7

Zinc 9 180 91.4 85.9-96.9

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

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

Station 

number

Station 

name

Dilution - 

ratio

Trace-element concentration, in ng/mL

CadmiumChromium Copper Iron Lead Nickel Zinc

12323600

12323750

12323770

12323800

461415112450801

461559112443301

461903112440701

12324200

12324680

12331500

12331800

12334510

12334550

12340500

12353000

Silver Bow Creek at Opportunity 1 : 1

Silver Bow Creek at Warm Springs 1 : 1

Warm Springs Creek at Warm Springs 1 : 1

Clark Fork near Galen 1 : 1

Clark Fork below Lost Creek, near Galen 1 : 1

Clark Fork near Racetrack 1 : 1

Clark Fork at Dempsey Creek diversion, 1 : 1 

near Racetrack

Clark Fork at Deer Lodge 1 : 1

Clark Fork at Goldcreek 1 : 1

Flint Creek near Drummond 1 : 1

Clark Fork near Drummond 1 : 1

Rock Creek near Clinton 1 : 1

Clark Fork at Turah Bridge, near Bonner 1 : 1

Clark Fork above Missoula 1 : 1

Clark Fork below Missoula 1 : 1

<0.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<.004

<004

<.004

<.004

<.004

<.004

<.004

0.02 <0.01 <0.10 <0.02

<.01 <.01 <.10 <.02

<.01 .05 <.10 <.02

.04 <.01 <.10 <.02

<.01 .03 .25 <.02

.02 <.01 <.10 <.02

<.01 <.01 <.10 <.02

.02 <.01 .36 <.02

<.01 .04 .17 <.02

<.01 <.01 .21 <.02

<.01 <.01 .29 <.02

<.01 <.01 <.10 <.02

<.01 <.01 .17 <.02

<.01 <.01 <.10 <.02

<.01 <.01 <.10 <.02

0.01 <0.01 0.01

<.01 <.01 .02

.01 <.01 .03

.01 <.01 .01

.02 <.01 .02

<.01 <.01 <.01

.02 <.01 <.01

.02 <.01 .03

<.01 <01 .02

<.01 <.01 .04

<01 <01 .19

<.01 <.01 <.01

<.01 <.01 <.01

.01 <.01 .03

<.01 <.01 .02

60 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

through September 1997

[Abbreviations: fVVs, cubic feet per second; °C, degrees Celsius; ug/L, micrograms per liter; uS/cm, microsiemens per centimeter at 25 °C; mg/L, 

milligrams per liter; mm, millimeter; ton/d, tons per day. Symbols: <, less than minimum 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 (ft /s)

Specific conductance, onsite (nS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCC^)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (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)

Mean

MONT,

Median

: March 1993-August 1995, December 199 6 -September 1997

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36

156

412

17.0

8.2

140

39

11

18

13

<1

.1

52

10

4,200

440

47

1

240

100

130

11

139

59

96

3.1

116

2.0

7.3

38

11

2.7

2

1

<1

<.l

2

<1

260

24

<1

<.5

30

17

<10

<3

2

.04

50

19

253

8.1

7.8

100

29

6.9

7

5

--

--

10

24

929

190

24

2.2

68

42

2 15

25

22

2.8

83

9.2

248

7.0

7.8

100

30

6.8

7

4

<1

<.l

7

4

610

180

1

<.5

60

40

<10

4

8

.2

87

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

through September 1997 (Continued)

Property or constituent and reporting unit

Number of 

samples

12323250-SILVER BOW CREEK BELOW BL

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 (|*g/L)

Iron, total recoverable (|*g/L)

Iron, dissolved (p.g/L)

Lead, total recoverable (|ag/L) 

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (|*g/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)

Maximum Minimum

ACKTAIL CREEK. AT BU1

Mean

PTE. MONT.

: March 1993- August 1995, December 1996-September 1997

36 134 15 35

36

36

36

36

36

36

36

36

36

36

36

36

36

36

36 

36

36

36

36

36

35

35

35

691

17.0

7.8

180

50

13

45

13

6

6.2

550

300

7,400

270

250 

2.4

1,600

1,700

2,200

2,200

194

70

93

226

1.5

7.2

66

19

4.5

10

4

1

.5

85

22

310

26

3 

<.5

320

210

350

200

3

.14

42

458

10.0

7.5

142

41

10

17

8

3

2.4

207

91

1,580

116

33 

2.9

780

708

1,020

829

37

5.3

81

Median

27

466

9.0

7.5

145

42

10

16

8

3

2.1

185

78

870

110

13 

.8

750

690

965

765

16

1.2

86

62 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for streams 

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

through September 1997 (Continued)

Property or constituent and reporting unit

Number of 

samples

12323600-SILVER BOW CREEK

Maximum Minimum Mean Median

AT OPPORTUNITY. MONT.

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

Streamflow, instantaneous (ftVs) 38 361 26 98

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 (|J.g/L) 

Lead, dissolved (ng/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L)

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

Zinc, dissolved (ng/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

37

37

37

37

37

37

37

37

37

37

37

37

37

37

37 

37

37

37

37

37

38

38

38

593

18.0

8.9

200

54

15

230

34

49

41

3,900

450

24,000

310

650 

5.1

10,000

9,300

15,000

13,000

801

781

92

202

0.0

7.2

60

18

3.4

11

1

1

.5

79

25

290

3

7 

<.5

230

190

230

110

6

.42

37

359

8.5

8.2

128

38

8.1

37

10

4

2.4

355

75

2,450

67

60 

2.9

890

754

998

657

80

41

74

1997

60

368

8.5

8.1

130

40

8.1

19

9

2

1.2

160

54

1,000

45

18 

.5

610

500

580

310

25

4.2

78

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

through September 1997 (Continued)

Property or constituent and reporting unit

12323750-SILVER

Number of 

samples Maximum Minimum Mean Median

BOW CREEK AT WARM SPRINGS. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s) 44

Specific conductance, onsite (fiS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCC^)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (fig/L)

Arsenic, dissolved (f*g/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (f*g/L)

Copper, dissolved (fig/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L) 

Lead, total recoverable (ng/L)

Lead, dissolved (f*g/L)

Manganese, total recoverable (ng/L)

Manganese, dissolved (ng/L) 

Zinc, total recoverable (ng/L) 

Zinc, dissolved (fig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

42

43

42

42

42

42

42

42

42

42

42

42

42

42 

42

42

42

42 

42 

42

44

44

43

March

662

614

22.0

9.3

260

78

19

94

60

<1

.3

80

40

3,000

93 

15

1.0

600

530 

180

73

229

279

97

1993-September 1997

24

265

.5

8.0

110

34

5.9

12

8

<1

<.l

10

6

130

3

<.5

70

12 

<3

2

.26

43

191

434

11.0

8.8

182

54

12

28

22

--

2 .1

29

15

479

19

23

--

210

135 

264 

2 14

17

14

81

148

431

12.0

8.8

175

52

12

24

20

<1

<.l

24

12

385

15

2

<.5

180

98 

50 

9

8

2.6

82

64 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for streams 

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

through September 1997 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12323770-WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

Period of record for water quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (jaS/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 (jag/L)

Arsenic, dissolved (jag/L)

Cadmium, total recoverable (jag/L)

Cadmium, dissolved (jag/L)

Copper, total recoverable (ng/L)

Copper, dissolved (jag/L)

Iron, total recoverable (jag/L)

Iron, dissolved (jag/L)

Lead, total recoverable (jag/L)

Lead, dissolved (jag/L)

Manganese, total recoverable (jag/L)

Manganese, dissolved (jag/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)

28

27

28

27

27

27

27

27

27

27

27

27

27

27

27

27

27

27

27

27

27

28

27

28

March

420

795

16.0

8.6

420

130

22

27

14

<1

<.l

97

16

1,700

30

14

1.8

1,400

570

60

10

100

87

88

1993-September 1997

2.8

139

.5

7.4

72

22

3.8

3

3

<1

<.l

4

1

40

3

<1

<.5

90

43

<10

<3

3

.14

55

127

309

8.3

8.2

152

46

8.8

9

5

~

-

29

5

461

12

23

~

307

172

2 17

23

28

17

76

92

267

8.0

8.2

130

40

7.3

6

5

<1

<.l

11

3

160

10

1

<.5

270

110

10

<3

12

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 1997 (Continued)

Property or constituent and reporting unit

12323800-CL

Number of 

samples Maximum Minimum Mean Median

ARK FORK NEAR GALEN. MONT.

Period of record for water-quality data: July 1988-September 1997

Streamflow, instantaneous (ft3/s) 85 1,050 14

Specific conductance, onsite (^iS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCC^)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (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 (jig/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)

73

84

72

71

71

71

71

71 

71

71

70

71

71

71 

71 

71

71

71

71

71

85

85

84

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

220

.0

7.5

96

29

5.5

3

4

<1

8

3

90

3

80

31

10

3

2

.12

41

231

434

9.5

8.4

191

57

12

21

15

2.3

2.1

42

12

711

19

25 

2 .4

304

130

67

17

24

30

78

136

438

9.2

8.4

190

57

12

16

12

<1

30

10

350

12 

3

250

110

50

12

9

2.9

78

66 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for streams 

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

through September 1997 (Continued)

Property or constituent and reporting unit

12324200-CL

Number of 

samples Maximum

ARK FORK AT DEER LODGE,

Period of record for water-quality data

Streamflow, instantaneous (ft3/s) 137

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 (^g/L)

Arsenic, dissolved (^g/L) 

Cadmium, total recoverable (jag/L) 

Cadmium, dissolved (^ig/L)

Copper, total recoverable (^ig/L)

Copper, dissolved (^ig/L)

Iron, total recoverable (^ig/L) 

Iron, dissolved (^ig/L) 

Lead, total recoverable (^ig/L) 

Lead, dissolved (Mg/L)

Manganese, total recoverable (^ig/L)

Manganese, dissolved (ng/L)

Zinc, total recoverable (^ig/L)

Zinc, dissolved (^ig/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

120

136

85

77

77

77

87

87 

87 

87

86

87

87 

87 

87 

87

87

87

87

87

137

137

128

Minimum

. MONT.

: March 1985-September 1997

1,920 23

642

23.0

8.7

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

242

.0

7.4

100

32

5.9

8

7 

<1 

<.l

11

4

Mean

308

495

9.3

8.2

207

61

13

29

15

2 .7

2.1

121

14

60 2,400 

<3 2 18 

<1 2 16 

<.5 2.6

30

1

10

3

2

.29

40

350

47

138

18

94

223

70

Median

219

514

10.0

8.2

210

62

14

18

13 

<1 

<]

52

10

820 

10 

6 

<1

190

34

70

13

25

15

71

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

through September 1997 (Continued)

Property or constituent and reporting unit

12324590-LITTLE BL

Number of 

samples Maximum Minimum Mean Median

ACKFOOT RIVER NEAR GARRISON. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (frVs)

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 (|J.g/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)

72

60

71

59

54

54

54

59

59

59

59

58

59

59

59

59

58

59

59

59

59

72

72

72

March 1985-September 1997

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

95

21

120

.0

7.0

51

14

3.3

4

3

<1

<.l

<1

<1

20 1,

<3

<1

<.5

<10

1

<10

<3

1

.08

49

319

219

7.5

8.0

100

29

6.8

7

5

2 .3

--

25

22

520

238

24

2 .5

288

8

2 17

24

63

184

74

186

215

7.0

8.0

99

28

6.8

6

5

<1

<1

3

2

330

26

1

<1

30

7

<10

3

10

6.6

78

68 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for streams 

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

through September 1997 (Continued)

Property or constituent and reporting unit

12324680-CL

Number of 

samples Maximum Minimum Mean Median

,ARK FORK AT GOLDCREEK MONT.

Period of record for water-quality data

Streamflow, instantaneous (ft3/s) 43

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 (|ag/L)

Copper, total recoverable (\igTL)

Copper, dissolved (ng/L)

Iron, total recoverable (ng/L) 

Iron, dissolved (|^g/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)

42

43

42

42

42

42

42

42

42

42

41

41

42 

42 

41

41

42

42

42 

42

43

43

43

: March 1993-September

3,920 87

496

20.0

8.7

230

68

15

75

20

2

<.2

440

36

12,000 

100

73

.6

1,100

43

510 

26

752

7,960

93

207

.0

7.9

86

26

5.1

8

6

<1

<.l

8

3

60 

<3 

<1

<.5

30

10

10 

<3

2

.94

43

1997

954

360

8.8

8.3

158

47

10

19

11

-

--

64

9

1,430 

224 

29

-

177

22

76 

29

84

456

74

721

372

8.0

8.3

160

49

10

16

10

<1

<.l

43

7

810 

16 

6

<5

130

20

50 

8

39

53

78

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

through September 1997 (Continued)

Property or constituent and reporting unit Number of 

samples Maximum Minimum Mean Median

12331SOft-F^INT CREEK NEAR DRUMMOND. MONT.

Period of record for water-quality data:

Streamflow, instantaneous (frVs) 92

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)

81

90

78

71

71

71

78

78 

78

78

77 

78

78

78 

78 

78

78

78 

78 

78

92

92

92

March

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

1985-September 1997

4.2

134

.0

7.5

59

16

4.3

7

5 

<1

<.l

1 

<1

70 1

3 

<1

<.5

50

14 

<10

<3

3

.03

28

201

293

8.5

8.2

138

37

11

19

9

2 .2

--

8

22

,120

45 

2 14

2 1

245

41 

247 

26

59

55

80

126

294

9.0

8.3

140

38

11

15

9

<1

<.l

7 

2

610

28 

9 

<5

160

36 

30 

4

32

9.6

84

70 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summariea of data for atreams 

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 1997 (Continued)

Property or constituent and reporting unit

12331800-CL

Number of 

samples

ARK FORK NEAR

Period of record for water-quality data:

Streamflow, instantaneous (ft3/s)

Specific conductance, onsite (jaS/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 (jag/L)

Arsenic, dissolved (jag/L)

Cadmium, total recoverable (ng/L)

Cadmium, dissolved (jag/L)

Copper, total recoverable (ng/L)

Copper, dissolved (jag/L)

Iron, total recoverable (jag/L)

Iron, dissolved (jag/L)

Lead, total recoverable (jag/L)

Lead, dissolved (ng/L)

Manganese, total recoverable (jag/L)

Manganese, dissolved (|ag/L)

Zinc, total recoverable (ng/L)

Zinc, dissolved (jag/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

43

42

43

42

42

42

42

42

42

42

42

40

40

42

42

38

38

42

42

42

42

43

43

43

Maximum Minimum Mean Median

DRUMMOND. MONT.

March

3,860

630

21.0

8.5

300

83

22

62

20

2

.2

360

21

8,800

150

56

1.2

880

50

490

21

530

4,720

91

1993-September 1997

149 1,310

189

.5

7.8

74

21

5.2

8

7

<1

<.l

5

1

50 1

<3

<1

<.5

20

8

<10

<3

2

1.9

38

384

9.8

8.2

173

50

12

21

11

-

-

66

8

,580

227

2 13

2 .3

209

19

299

29

98

576

72

985

401

9.0

8,2

180

52

12

16

11

<1

<.l

40

6

895

14

9

<.5

150

16

65

7

45

107

72

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

through September 1997 (Continued)

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

12334510-ROCK CREEK NEAR CLINTON. MONT. 

Period of record for water-quality data: March 1985-September 1997

Streamflow, instantaneous (ft3/s) 71 5,060 113 1,040 558

Specific conductance, onsite (MS/cm) 62 155 55 104 94

Temperature, water (°C) 71 18 .0 7.9 8.0

pH, onsite (standard units) 61 8.6 6.9 7.9 7.9

Hardness, total (mg/L as CaCO3) 53 90 22 49 49

Calcium, dissolved (mg/L) 53 23 5.9 13 13

Magnesium, dissolved (mg/L) 53 8.0 1.9 4.2 4.0

Arsenic, total recoverable (Mg/L) 59 3 <1 2 .9 <1

Arsenic, dissolved (Mg/L) 59 1 <1 2 1 <1

Cadmium, total recoverable (Mg/L) 59 3 <1 2 .4 <1

Cadmium, dissolved (Mg/L) 59 1 <.l - <1

Copper, total recoverable (Mg/L) 57 41 <1 25 3

Copper, dissolved (Mg/L) 58 6 <1 2 1 1

Iron, total recoverable (Mg/L) 59 2,100 20 381 200

Iron, dissolved (Mg/L) 59 160 5 40 35

Lead, total recoverable (Mg/L) 57 19 <1 22 <5

Lead, dissolved (Mg/L) 57 5 <.5 2 .7 <1

Manganese, total recoverable (Mg/L) 59 90 <10 2 19 10

Manganese, dissolved (Mg/L) 59 8 <1 2 2

Zinc, total recoverable (Mg/L) 59 60 <10 2 10 <10

Zinc, dissolved (Mg/L) 59 15 <3 22 <3

Sediment, suspended concentration (mg/L) 71 223 1 25 6

Sediment, suspended discharge (ton/d) 71 3,050 .31 173 14

Sediment, suspended (percent finer than 0.062 mm) 71 95 35 69 70

72 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for streams 

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

through September 1997 (Continued)

Property or constituent and reporting unit

12334550-CLARK FORK

Number of 

samples Maximum Minimum

AT TURAH BRIDGE. NEAR BONNER.

Period of record for water-quality data

Streamflow, instantaneous (ft3/s) 140

Specific conductance, onsite (|aS/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCC^)

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (ng/L)

Arsenic, dissolved (ng/L)

Cadmium, total recoverable (|ag/L)

Cadmium, dissolved (ng/L)

Copper, total recoverable (ng/L)

Copper, dissolved (|Jg/L)

Iron, total recoverable (|ag/L) 

Iron, dissolved (|ag/L)

Lead, total recoverable (ng/L) 

Lead, dissolved (ng/L)

Manganese, total recoverable (|Jg/L)

Manganese, dissolved (jag/L) 

Zinc, total recoverable (|ag/L) 

Zinc, dissolved (|ag/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

115

139

86

76

76

76

85

85

85

85

83

84

85 

85

81 

81

85

85 

85 

85

140

: March

9,560

483

22.0

8.7

210

59

14

110

17

4

1

500

25

19,000 

190

100

7

2,000

37 

1,100 

39

1,370

140 34,700

129 98

Mean

MONT.

1985-September 1997

296 1,900

140

.0

7.4

58

17

3.9

5

4

<1

<-l

3

2

60

<3

<l

10

1

<3

2

3.5

27

311

9.0

8.2

136

38

9.6

12

6

2 .5

--

52

6

1,560

229

2 .5

178

9 

2 91 

29

70

828

71

Median

1,120

329

9.5

8.2

140

39

9.5

8

6

<1

<1

27

5

590 

16

6

90

7 

40

7

23

66

72

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

through September 1997 (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 (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 (|ig/L)

Copper, dissolved (|ig/L)

Iron, total recoverable (ng/L)

Iron, dissolved (ng/L)

Lead, total recoverable (|ig/L)

Lead, dissolved (|ig/L)

Manganese, total recoverable (|ig/L)

Manganese, dissolved (|ig/L)

Zinc, total recoverable (|ig/L)

Zinc, dissolved (i^g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

101

78

101

61

54

54

54

61

61

61

61

58

59

61

61

57

57

61

61

61

61

101

101

99

March

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

1985-September 1997

344 2

130

.0

7.5

55

14

4.9

<1

<1

<1

<.l

<1

<1

20

<3

<1

<.5

<10

<1

<10

<3

1

1.1

42

,750

205

8.8

8.2

100

26

8.9

2 1

2.9

2 .4

--

29

22

628

221

2 5

2 1

240

23

2 11

24

35

639

78

1,260

202

8.5

8.3

94

24

8.4

1

<1

<1

<1

6

2

260

14

2

<1

20

2

<10

<3

8

29

80

74 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for streams 

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

through September 1997 (Continued)

Property or constituent and reporting unit

12340500-CL

Number of .. . samples Maximum

ARK FORK ABOVE MISSOUl

Period of record for water-quality data

Streamflow, instantaneous (ft /s)

Specific conductance, onsite (|o.S/cm)

Temperature, water (°C)

pH, onsite (standard units)

Hardness, total (mg/L as CaCO3 )

Calcium, dissolved (mg/L)

Magnesium, dissolved (mg/L)

Arsenic, total recoverable (|4.g/L)

Arsenic, dissolved (ng/L)

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

Cadmium, dissolved (|o.g/L)

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

Copper, dissolved (|4.g/L)

Iron, total recoverable (ng/L)

Iron, dissolved (|4.g/L)

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

Lead, dissolved (|o.g/L)

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

Manganese, dissolved (|4.g/L)

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

Zinc, dissolved (|4.g/L)

Sediment, suspended concentration (mg/L)

Sediment, suspended discharge (ton/d)

Sediment, suspended (percent finer than 0.062 mm)

106

83

103

63

63

63

63

63

63

63

63

61

62

63

63

58

58

63

63

63

63

106

106

101

Minimum

,A. MONT.

Mean Median

: July 1986-September 1997

21,600

399

19.5

8.6

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 4,

145

.0

7.9

61

14

5.3

2

1

<1

<.l

2

1

60

<3

<1

<.5

10

7

<10

<3

2

6.1 1,

44

570

257

9.0

8.2

118

32

9.2

6

3

-

-

21

3

811

226

24

2.6

80

19

243

25

43

190

86

2,320

261

8.5

8.3

120

32

9.2

4

3

<1

<-l

8

2

310

16

2

<.5

50

15

20

4

10

60

89

'Multiple minimum reporting levels during the period of record may result in varying values identified with a less-than (<) symbol.

2 Value is estimated by using a log-probability regression to predict the values of data less than the minimum reporting level (Helsel and Cohn, 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 1997

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

weight. Symbols: <, less than minimum reporting level; --, indicates either too few samples or 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. Values for single samples are 

arbitrarily listed in the "Mean" column]

_ ... . Number of Constituent . samples

Maximum

Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY. MONT.

Period of record for fine-grained bed-sediment data: 1992-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

6

5

6

6

6

6

5

6

6

42.0

31.0

6,280

41,200

1,030

3,940

21.4

19.6

10,800

25.5 33.1

23.2 27.2

4,560 4,980

34,400 38,600

752 856

1,680 2,590

14.5 16.9

13.7 16.5

6,850 8,480

33.0

27.6

4,740

39,000

833

2,440

16.2

16.8

8,340

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.

Period of record for fine-grained bed-sediment data: 1992-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

6

5

6

6

6

6

5

6

6

12.2

24.8

769

26,000

99

17,700

16.5

2.1

2,220

5.3 8.2

12.8 20.3

259 482

19,500 21,500

58 75

1,470 7,460

12.5 14.8

.3 1.3

620 1,300

7.4

22.9

440

20,800

74

7,630

14.6

1.1

1,150

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

2

2

2

2

2

2

2

2

2

3.9

33.4

892

22,400

86

8,790

21.9

3.7

421

2.6 3.2

30.8 32.1

848 870

21,900 22,100

85 86

2,020 5,400

17.6 19.8

3.2 3.4

372 396

~

~

--

--

--

-

--

76 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1986 through August 1997 (Continued)

Constituent . * ^ Minimum Mean Median

12323800-CLARK FORK NEAR GALEN. MONT.

Period of record for fine-grained bed-sediment data: 1987, 1991-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

8

5

8

8

8

8

5

8

8

20.1

33.9

2,300

39,800

235

15,600

23.2

5.5

3,560

7.5 11.7

22.1 28.0

1,140 J,430

22,600 29,300

116 155

2,780 9,150

17.7 20.1

2.8 4.1

1,160 2,100

11.2

29.9

1,250

28,400

144

10,400

19.7

3.9

2,080

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

Period of record for fine-grained bed-sediment data: 1996-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

2

2

2

2

2

2

2

2

2

9.0

34.5

2,050

31,400

197

5,900

19.9

7.0

1,680

8.4 8.7

32.9 33.7

1,730 1,890

30,800 31,100

190 194

3,540 4,720

18.7 19.3

6.8 6.9

1,460 1,570

--

-

--

-

--

-

-

--

~

461559112443301-CLARK FORK NEAR RACETRACK. MONT.

Period of record for fine-grained bed-sediment data: 1996-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

2

2

2

2

2

2

2

2

2

8.5

33.3

1,610

29,800

155

2,680

18.4

6.1

1,550

7.5 8.0

30.1 31.7

1,370 1,490

29,000 29,400

153 154

2,390 2,540

16.5 17.4

6.0 6.0

1,190 1,370

-

--

--

--

-

-

--

--

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

Period of record for fine-grained bed-sediment data: 1996-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

2

2

2

2

2

2

2

2

2

8.1

31.1

1,550

30,200

152

3,910

16.9

6.2

1,570

6.9 7.5

28.9 30.0

1,280 1,420

28,200 29,200

152 152

2,630 3,270

15.8 16.4

6.2 6.2

1,260 1,420

--

--

--

--

--

--

--

-

--

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

August 1986 through August 1997 (Continued)

Constituent Numbe[ of Maxi' 

samples mum Minimum Mean Median

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1990-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

10

5

10

10

10

10

5

10

10

9.0

36.5

4,180

31,700

242

6,020

19.0

7.9

1,730

5.1 7.1

19.5 31.1

837 1,610

22,600 27,900

121 165

1,460 2,670

15.0 16.7

2.4 4.8

977 1,370

7.5

35.4

1,220

28,900

159

2,380

16.8

4.9

1,420

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

3

1

3

3

3

3

1

3

3

.9

85

26,400

53

2,700

.9

180

.2 .6

22.1

38 54

16,100 22,100

37 43

907 1,550

13.6

<5 1 .5

161 170

.7

~

40

23,800

40

1,040

.3

170

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for fine-grained bed-sediment data: 1992-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

6

5

6

6

6

6

5

6

6

6.2

37.8

1,080

28,600

152

2,610

17.8

4.8

1,320

5.4 5.7

31.6 34.5

653 849

20,500 25,200

88 113

1,180 2,020

15.0 16.7

2.3 3.5

1,070 1,180

5.8

34.5

797

25,400

112

2,070

17.0

3.5

1,170

mtlSOO-FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for fine-grained bed-sediment data: 1986, 1989, 1992-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

8

5

8

8

8

8

5

7

8

4.5

27.9

73

28,100

240

5,510

14.9

7.8

111

<1.0 1 2.6

21.1 24.6

55 63

21,100 24,000

151 186

2,360 3,790

11.7 12.9

5.0 6.5

610 679

2.8

24.3

64

23,500

179

3,740

12.5

6.5

673

78 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1986 through August 1997 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

« ... . Number of Maxi- ... . .. Consftuent Mmp|es mum Mm.mum Mean

12331800-CLARK FORK NEAR DRUMMOND. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 1991-97

9 5.4 4.1 4.7

5 35.4 17.0 29.8

9 747 469 578

9 26,100 16,500 22,400

9 135 83 102

9 2,780 1,220 1,860

5 16.8 14.0 15.6

9 4.7 2.1 3.2

9 1,230 1,000 1,110

12334510-ROCK CREEK NEAR CLINTON. MONT.

Period of record for fine-grained bed-sediment data: 1986-87, 89, 1991-97

10 <1.5 <.3 -- 1

5 27.9 16.5 22.3

10 15 3 12

10 21,400 13,100 17,700

10 16 <3 1 S

10 618 126 366

5 13.7 10.8 12.4

9 .8 <.3 '.3

10 58 36 47

1 2TU550-CLARK FORK AT TURAH BRIDGE. NEAR BONNER. MONT.

Period of record for fine-grained bed-sediment data: 1986, 1991-97

8 5.2 3.1 3.8

5 34.7 15.3 25.2

8 635 300 414

8 23,200 15,100 19,400

8 115 49 77

8 1,700 671 1,160

5 16.2 11.6 14.4

8 3.9 1.3 2.3

8 1,160 775 927

12340000-BLACKFOOT RIVER NEAR BONNER. MONT.

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

7 <1.5 <.3 - 1

4 24.7 15.1 19.3

7 25 16 21

7 19,100 12,400 16,300

7 20 <13 '12

7 672 298 497

4 13.3 11.7 12.6

7 .7 <.3 '.3

7 73 54 63

Median

4.8

32.6

579

23,800

102

1,880

15.7

3.1

1,120

'<.8

21.4

13

17,800

8

330

12.7

<.5

48

3.6

26.7

339

19,500

72

1,200

15.9

2.3

898

'<.8

18.6

21

15,800

11

497

12.6

l<.5

61

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

August 1986 through August 1997 (Continued)

Constituent Number of 

samples

Maximum

Minimum Mean Median

12340500-CLARK FORK ABOVE MISSOULA. MONT. 

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

Cadmium 1 ~ ~ 3.7 

Chromium 1 - - 28.5 

Copper 1 -- -- 516 

Iron 1 -- -- 21,800 

Lead 1 ~ ~ 63 

Manganese 1 -- -- 1,160 

Nickel 1 - - 14.5 

Silver 1 -- -- 2.9 

Zinc 1 ~ - 924

12353000-CLARK FORK BELOW MISSOULA. MONT.2

Period of record for fine-grained bed-sediment data: 1986, 1990-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

9

5

9

9

9

9

5

9

9

2.6

27.6

293

21,100

58

2,530

14.1

2.1

675

1.1

18.8

98

14,500

12

752

11.8

.4

319

1.7

22.9

166

18.600

37

1,480

13.2

1.2

433

1.8

21.5

138

19,500

35

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. 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 1996 through September 1997) 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 1997

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

Symbols: <, less than minimum reporting level; , indicates either too few samples or 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. Values for single samples are arbitrarily 

listed in the "Mean" column]

- ... . Number of Constituent samp|es Maximum Minimum Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY. MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

4

4

4

4

4

4

4

4

4

12.7

16.2

1,550

29,300

300

1,670

8.9

4.8

3,420

5.4 8.3

9.6 13.3

775 1,030

18,600 23,700

221 258

504 898

6.0 6.9

3.4 4.0

1,720 2,360

7.6

13.8

904

23,400

255

708

6.4

4.0

2,160

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.

Period of record for bulk bed-sediment data: 1993, 1995-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

4

4

4

4

4

4

4

4

4

1.7

11.8

111

12,300

33

884

9.2

1.3

303

<1.1 '1.2

9.9 10.8

42 76

9,160 10,900

<10 ! 18

209 617

5.3 7.0

<.3 '.7

137 209

'1.2

10.9

76

11,100

16

687

6.8

'.6

198

12327700-WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

2

2

2

2

2

2

2

2

2

1.0

11.8

205

10,900

34

2,650

7.8

1.1

148

<8 7

9.7 10.8

203 204

8,980 9,960

18 26

1,220 1,930

5.7 6.8

.9 1.0

146 147

--

-

-

--

--

-

--

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

August 1993 through August 1997 (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

Constituent . " Minimum Mean

12323800-CLARK FORK NEAR GALEN. MONT.

Period of record for bulk bed-sediment data: 1993-97

5 6.0 1.5 3.2

5 23.0 4.2 13.8

5 685 223 435

5 31,300 9,930 20,600

5 87 41 65

5 5,410 899 2,200

5 12.5 4.9 8.3

5 1.9 .7 1.4

5 1,280 417 709

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

Period of record for bulk bed-sediment data: 1996-97

2 3.1 2.5 2.8

2 17.5 12.0 14.8

2 763 455 609

2 21,000 16,000 18,500

2 104 72 88

2 1,740 1,260 1,500

2 8.2 7.7 8.0

2 2.8 2.1 2.4

2 787 632 710

4615591 12443301-CLARK FORK NEAR RACETRACK. MONT.

Period of record for bulk bed-sediment data: 1996-97

2 3.4 1.9 2.6

2 16.4 12.4 14.4

2 594 361 478

2 18,200 16,200 17,200

2 87 66 76

2 1,500 759 1,130

2 9.9 5.5 7.7

2 2.6 1.9 2.2

2 743 472 608

Median

2.6

14.8

408

22,500

64

1,540

8.8

1.6

653

-

--

--

--

--

--

-

--

--

~

~

--

--

--

461 9031 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: 1996-97

2 3.9 1.8 2.8

2 17.3 16.3 16.8

2 651 424 538

2 20,900 20,100 20,500

2 89 58 74

2 1,860 825 1,340

2 10.0 5.5 7.8

2 2.8 2.0 2.4

2 804 448 626

-

-

--

~

--

--

~

--

~

82 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1993 through August 1997 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

-, ... . Number of Maxi- ... . .. Constituent ...».,i.«. «., Minimum Mean samples mum

12324200-CLARK FORK AT DEER LODGE. MONT.

Period of record for bulk bed-sediment data: 1993-97

5 3.1 2.0 2.5

5 24.5 12.1 17.1

5 691 281 435

5 25,000 13,200 18,400

5 85 45 71

5 2,060 653 1,160

5 10.4 7.7 9.3

5 2.8 <.7 '1.6

5 777 456 596

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

Period of record for bulk bed-sediment data: 1994

1 -- -- <1.2

1 -- -- 14.7

1 - - 19

1 - - 15,600

1 - - 12

1 - -- 420

1 - - 8.6

1 -- -- <.7

1 - -- 73

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for bulk bed-sediment data: 1993-97

5 5.2 2.3 3.5

5 33.2 17.6 24.8

5 858 282 546

5 24,900 15,500 20,300

5 86 46 70

5 2,600 649 1,350

5 15.9 9.1 12.9

5 3.7 <.7 '2.2

5 1,020 549 774

12331500-FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-97

5 3.2 .3 1.5

5 13.9 4.9 10.2

5 40 19 30

5 15,000 8,630 13,000

5 120 51 83

5 3,200 1,150 2,250

5 8.0 5.3 6.4

5 5.8 3.3 4.7

5 429 190 314

Median

2.4

16.1

383

17,900

74

1,020

10.1

1.6

599

~

--

~

-

--

-

--

~

3.4

23.4

471

19,600

72

1,190

12.4

1.6

696

1.5

10.7

30

13,400

80

2,240

6.0

5.1

332

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

August 1993 through August 1997 (Continued)

- ... . Number of Constituent samples

Maxi- ... . .. Minimum Mean

mum

Median

12331800-CLARK FORK NEAR DRUMMOND. MONT.

Period of record for bulk bed-sediment data: 1993-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

5

5

5

5

5

5

5

5

5

3.9 1.5 2.5

29.5 13.8 22.0

605 173 356

21,800 14,100 17,800

78 35 55

1,510 711 1,040

14.2 9.0 11.7

3.5 .5 1.9

939 434 680

1.8

23.1

276

16,600

58

1,210

11.0

1.7

621

12334510-ROCK CREEK NEAR CLINTON. MONT.

Period of record for bulk bed-sediment data: 1993-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

5

5

5

5

5

5

5

5

5

<1.5 <.8 --'

14.3 6.6 9.7

746

11,100 6,380 8,740

<13 5 '5

258 91 175

8.2 4.9 6.0

.4 .1 '.3

29 16 20

J <1.1

8.9

6

8,960

'5

186

5.7

'.3

20

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

Period of record for bulk bed-sediment data: 1993-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

5

5

5

5

5

5

5

5

5

2.9 .5 J 1.5

23.8 6.9 14.4

336 75 192

17,900 9,530 13,100

49 21 34

1,320 234 560

14.0 6.4 9.3

2.0 <.3 '.9

769 281 483

1.6

15.5

182

13,200

35

414

8.8

] <.7

508

12340000--BLACKFOOT RIVER NEAR BONNER. MONT.

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

2

2

2

2

2

2

2

2

2

<1.2 <.8 --

17.7 6.7 12.2

19 14 16

16,600 10,300 13,400

10 8 9

305 179 242

9.8 7.6 8.7

<.7 <.5 --'

58 33 46

--

--

--

~

~

--

--

84 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1993 through August 1997 (Continued)

Constituent Number of 

samples

Maxi- ... . Minimum 

mum

Mean Median

12340500-CLARK FORK ABOVE MISSOULA. MONT.

Period of record for bulk bed-sediment data: 1997

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

1

1

1

1

1

1

1

1

1

12353000-CLARK FORK

_.

11

-.

..

..

BELOW MISSOULA. MONT.2

<.8

9.7

43

,500

7

228

8.2

.6

145

-

--

-

-

--

Period of record for bulk bed-sediment data: 1993-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Silver

Zinc

5

5

5

5

5

5

5

5

5

<1.5 <.8

12.6 4.4

77 22

'.6

7.8

47

11,300 6,160 8,680

19 <10

444 223

7.1 3.5

.6 <.3

172 88

4o

361

5.6

U

129

<l.l

7.8

49

8,830

'8

381

6.0

U

121

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. 

2 Samples 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 1997

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

too few samples 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

Mean Median

12323600-SILVER BOW CREEK AT OPPORTUNITY. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

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

Brachvcentrus spp.

1

1

1

1

1

1

1

1

Hydropsyche cockeretti

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

1997

11.6

.7

587

335

7.4

231

1.0

888

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

--

-

-

-

--

-

4.7

3.1

333

953

20.1

434

1.6

805

6.9

1.8

298

1,050

18.3

675

1.6

1,020

12323750-SILVER BOW CREEK AT WARM SPRINGS. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1992-97

Hydropsyche cockeretti

16 2.1 .5

16 1.3 .5

16 96.9 25.1

16 1,240 553

16 5.7 .3

16 2,450 491

16 1.8 .4

16 276 118

1.0

.8

51.0

783

3.5

1,060

.9

193

.7

.8

43.9

758

3.5

873

.8

195

86 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1997 (Continued)

Number of M . 

Constituent composite " Minimum 

samples mum

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: 1992-97

Hydropsyche occidentalis

3 1.1 .4

3 .9 .3

3 46.5 38.6

3 1,040 372

3 <3.6 <2.3

3 2,250 1,780

3 1.5 .7

3 202 149

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

.8

.6

41.5

803

'1.6

2,060

1.0

184

1.1

.8

40.9

680

2.9

725

'.8

195

.9

.7

39.4

998

'1.7

2,140

.9

201

.9

1.2

40.6

693

4.7

678

'.5

177

12323770- WARM SPRINGS CREEK AT WARM SPRINGS. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1995, 1997

Arctopsyche grandis

2 2.4 2.1

2 1.9 1.4

2 98.8 95.6

2 1,040 684

2 5.6 <6.3

2 2,280 1,340

2 2.3 1.8

2 222 197

Hydropsyche spp.

1

1

1

1

1

1

1

1

2.2

1.6

97.2

862

! 4.4

1,810

2.0

210

<9.3

1.6

94.8

1,150

<16.7

956

2.0

129

--

--

--

--

--

--

--

-

--

--

--

--

--

--

--

-

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

August 1997 (Continued)

Constituent

Number of 

composite 

samples

Maxi- ... . ^ Minimum 

mum

Mean Median

12323800-CLARK FORK NEAR GALEN. MONT.

Period of record for biological data: 1987, 1991-97

Hydropsyche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

12

12

12

12

12

12

12

12

2.7 1.3

3.3 .8

181 72.8

1,510 902

11.0 1.2

2,950 1,070

3.1 1.0

299 136

1.8

1.4

100

1,200

6.3

1,980

1.6

216

1.8

1.2

98.1

1,170

7.6

1,980

1.5

222

Hydropsyche morosa group

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

5

5

5

5

5

5

5

5

3.2 2.4

4.6 1.8

185 156

1,890 1,360

12.4 7.1

3,960 2,360

3.6 1.9

349 292

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 occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

20

20

20

20

20

20

20

20

1.7 .9

6.6 .7

106 66.7

1,920 642

13.5 1.6

4,070 1,220

3.5 1.1

278 170

1.2

1.8

84.7

1,210

6.6

2,480

1.7

206

1.2

1.6

83.1

1,220

6.3

2,360

1.6

201

Hydropsyche tana

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

1

1

1

1

1

1

1

1

_.

._

--

..

__

--

-

--

1.5

1.4

92.9

1,340

9.0

2,160

2.1

206

-

--

--

--

--

--

--

--

Hydropsyche spp.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

4

0

4

4

4

0

0

4

3.5 2.6

._

154 135

1,540 1,190

13.5 10.5

..

__

329 279

3.0

-

148

1,400

12.2

--

-

308

3.0

-

152

1,450

12.4

--

--

313

88 Water-quality, bed-sediment, and bioiogical data (October 1996 through September 1997) 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 1997 (Continued)

Number of M .

Constituent composite ax'~ Minimum

samples mum

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: 1996-97

Hydropsyche cockerelli

4 2.8 2.2

4 2.5 1.8

4 147 121

4 1,900 1,560

4 14.8 12.1

4 1,850 1,250

4 1.9 1.1

4 250 221

Hydropsyche occidentalis

6 1.8 1.4

6 2.5 1.7

6 157 121

6 1,920 1,360

6 12.4 9.8

6 2,190 1,270

6 1.7 1.4

6 252 230

Hydropsyche spp.

2 1.8 1.2

2 2.4 1.5

2 122 120

2 1,410 1,340

2 20.5 7.2

2 1,950 799

2 2.8 1.4

2 225 179

461559112443301--CLARK FORK NEAR RACETRACK.

Period of record for biological data: 1996-97

Hydropsyche cockerelli

4 1.7 1.1

4 2.5 .7

4 109 70.6

4 1,370 862

4 9.3 6.1

4 1,050 646

4 1.4 1.0

4 199 139

2.4

2.1

138

1,760

13.1

1,590

1.6

234

1.6

2.0

136

1,600

11.2

1,730

1.5

241

1.5

2.0

121

1,380

13.8

1,370

2.1

202

MONT.

1.4

1.5

92.4

1,130

7.7

831

1.2

175

2.4

2.0

142

1,780

12.7

1,630

1.6

233

1.6

1.9

135

1,580

11.1

1,730

1.5

241

--

--

--

--

--

--

-

-

1.4

1.4

94.8

1,140

7.7

815

1.2

180

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

August 1997 (Continued)

Number of 

Constituent composite Minimum 

samples mum

Mean Median

461559112443301-CLARK FORK NEAR RACETRACK. MONT. -Cnntinued

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-97

Hydropsvche occidentalis

6 2.2 1.4

6 2.6 1.5

6 160 93.5

6 1,880 1,300

6 11.7 9.7

6 2,640 1,090

6 1.7 1.2

6 255 229

Hydropsvche spp.

1

1

1

1

1

1

1

1

1.8

2.1

134

1,580

10.6

1,610

1.4

243

1.0

.7

82.9

1,140

5.7

910

1.1

151

1.9

2.3

145

1,600

10.4

1,110

1.4

246

~

~

-

-

~

--

-

--

4S1903112440701-CLARK FORK AT DEMPSEY CREEK DIVERSION. NEAR RACETRACK. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1996-97

Arctopsvche grandis

1

1

I

1

1

1

I

I

Hydropsvche 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

~

--

-

-

-

-

--

--

--

-

--

--

--

-

-

90 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1997 (Continued)

Constituent

Number of M , 

composite Minimum Mean 

samples mum

Median

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

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: 1996-97

Hydropsvche occidentalis

3 1.7 1.4 1.5

3 1.9 1.2 1.5

3 163 117 135

3 1,590 1,100 1,290

3 10.3 9.7 10.0

3 2,280 826 1,760

3 1.4 1.2 1.3

3 240 224 232

Hydropsvche spp.

2 1.7 1.6 1.6

2 2.1 1.4 1.8

2 140 104 122

2 1,610 1,070 1,340

2 13.2 10.5 11.8

2 1,150 638 892

2 1.6 1.6 1.6

2 212 191 202

lM24200-rrARK FORK AT DEER LODGE. MONT.

Period of record for biological data: 1986-87, 1990-97

Arctopsyche grandis

2 2.4 <4.2 '2.2

2 1.0 <1.3 '.8

2 69.1 34.9 52.0

2 676 537 606

2 <7.8 3.8 '3.8

2 727 380 554

2 <1.7 <1.3 '--

2 178 140 159

Hydropsvche cockereUi

17 2.3 .8 1.3

17 3.2 .4 1.7

17 136 54.7 96.8

17 3,340 490 1,180

17 18.2 4.3 8.9

17 1,030 396 683

17 2.4 .3 1.2

17 391 132 186

1.5

1.3

125

1,180

10.1

2,170

1.2

232

-

--

-

~

--

--

-

--

--

--

-

--

--

--

--

1.3

1.9

102

1,050

8.9

679

1.1

184

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

August 1997 (Continued)

Number of Mgx| 

Constituent composite _ Minimum

samples mum

Mean Median

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

Period of record for biological data: 1986-87, 1990-97

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Hydropsyche occidentalis

22 2.7 .8

22 2.6 .6

22 162 49.5

22 1,930 558

22 16.2 6.3

22 2,840 649

22 12.9 1.0

22 299 196

Hvdropsvche spp.

3 2.0 1.2

0

3 222 103

3 2,220 1,110

3 15.0 5.6

0

0

3 203 185

1.4

1.9

119

1,420

11.4

1,640

2.0

239

1.6

--

145

1,520

8.8

--

-

195

1.3

2.0

113

1,460

11.4

1,740

1.4

230

1.6

--

111

1,240

5.7

-

--

197

12324590-LITTLE BLACKFOOT RIVER NEAR GARRISON. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1987, 1994

Arctopsyche grandis

9 .4 .2

9 .8 .6

9 14.0 9.1

9 325 177

9 1.3 .5

9 596 318

9 .6 .4

9 179 113

Claassenia sabulosa

4 .3 .1

4 .8 .7

4 34.0 20.0

4 200 98

4 <.7 <.4

4 62.1 46.7

4 .7 .5

4 233 191

.3

.7

11.5

242

.8

471

.5

146

.2

.8

27.9

138

-- 1

53.4

.6

206

.3

.8

11.8

230

.8

492

.5

145

.2

.8

28.8

127

<.6

51.3

.5

201

92 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1997 (Continued)

Number of Maxj 

Constituent composite " Minimum 

samples mum

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

Hydropsyche cockeretti

1

1

1 

1

1

1 

1

1

Hydropsyche occidentalis

1

1

1 

1

1

1 

1

1 

12324680-CLARK FORK AT GOLDCREEK. MONT.

Period of record for biological data: 1992-97

Arctopsyche grandis

14 6.6 1.4

14 3.3 .8

14 129 28.8 

14 2,360 339

14 10.9 2.3

14 1,100 592 

14 1.8 .2

14 309 165

Claassenia sabulosa

12 3.5 .6

12 1.6 .3

12 67.7 33.0 

12 296 63.0

12 1.7 .5

12 179 65.1

12 .7 .2

12 296 166

.6

1.6

28.4 

478

3.6

399

1.2

123

<.7

1.3

15.1 

426

<3.7

434 

.8

110

2.4

1.6

63.6 

961

5.0

810 

.9

199

1.7

.7

54.5 

173

1.1

101

.3

244

~

~

-

~

--

--

--

;;

2.2

1.1

59.5 

682

3.8

776 

.8

187

1.4

.6

53.5 

174

1.1

91.0

.3

258

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

August 1997 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of 

Constituent composite Minimum Mean

. mum samples

12324680-CLARK FORK AT GOLDCREEK. MONT.-Continued

Period of record for biological data: 1992-97

Hvdropsvche cockerelli

12 2.6 .6 1.8

12 4.7 .7 2.6

12 188 33.5 98.3

12 3,250 589 1,420

12 16.2 4.5 8.7

12 954 538 699

12 2.3 .6 1.4

12 240 137 196

Hvdropsvche morosa group

4 1.7 1.1 1.4

4 1.4 1.3 1.4

4 72.9 43.8 60.5

4 1,320 612 1,050

4 6.9 2.4 4.6

4 1,030 538 804

4 1.4 .9 1.2

4 190 137 167

Hvdropsvche occidentals

10 1.7 .7 1.2

10 3.9 .4 1.5

10 156 26.4 65.2

10 2,720 466 1,100

10 15.7 2.9 7.2

10 1,800 530 1,070

10 1.9 .8 1.1

10 242 97 179

12331500-FLINT CREEK NEAR DRUMMOND. MONT.

Period of record for biological data: 1986, 1992-97

Arctopsvche grandis

30 .8 .2 .4

30 4.7 .6 1.9

30 21.7 8.7 15.2

30 2,460 606 1,370

30 17.5 3.7 9.1

30 2,480 679 1,520

30 2.7 .6 1.3

30 275 151 202

Median

1.8

2.2

87.7

1,030

7.6

650

1.3

204

1.4

1.4

62.7

1,130

4.6

822

1.2

170

1.2

1.2

47.0

787

5.8

931

1.1

180

.4

1.8

15.1

1,360

8.1

1,340

1.2

195

94 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1997 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of 

Constituent composite Minimum Mean

samples mum

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

Period of record for biological data: 1986, 1992-97

Hydropsyche cockerelli

1 .7 .2 A

1 2.2 1.0 1.5

7 28.3 9.5 18.1

7 2,180 996 1,560

7 17.9 3.1 10.6

7 1,440 401 994

7 2.3 .9 1.9

7 193 85 153

Hydropsyche occidentalis

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

Hydropsyche tana

2 <1.2 <1 -- 1

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

1 2331 800-CL ARK FORK NEAR DRUMMOND. MONT.

Period of record for biological data: 1986, 1991-97

Arctopsyche grandis

21 3.8 .7 1.6

21 2.5 .2 1.0

21 89.2 18.2 38.1

21 1,660 240 660

21 11.8 2.1 5.0

21 2,010 462 844

21 1.9 .2 .7

21 308 142 193

Median

.4

1.2

18.0

1,500

11.1

1,070

2.2

180

.6

1.8

18.0

1,780

19.3

1,760

2.9

185

-

--

--

--

--

--

--

--

1.5

1.0

32.0

576

4.2

710

.7

189

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

August 1997 (Continued)

Number of __. 

Constituent composite " Minimum 

samples mum

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, 1991-97

Claassenia sabulosa

27 2.8 .3

27 3.3 .3

27 130 18.0

27 290 76.1

27 2.2 .2

27 270 45.9

27 1.1 .1

27 469 140

Hydropsyche cockerelli

15 2.3 .7

15 3.5 .4

15 156 37.9

15 2,500 506

15 15.0 5.1

15 929 549

15 2.0 .5

15 240 164

Hydropsyche morosa group

6 1.3 1.1

6 2.8 1.9

6 57.4 50.2

6 1,730 1,380

6 10.8 7.0

6 1,940 1,260

6 1.7 1.3

6 250 227

Hydropsyche occidentalis

10 2.0 .7

10 8.1 .4

10 118 13.3

10 2,060 424

10 13.5 2.9

10 2,920 619

10 2.4 .5

10 283 157

Hydropsyche spp.

\

0

1

1

1

0

0

I

1.4

.8

60.4

138

.8

128

.3

258

1.6

1.9

78.3

1,310

8.9

745

1.2

197

1.2

2.3

55.2

1,570

8.9

1,610

1.5

239

1.1

2.3

54.3

1,170

7.9

1,500

1.4

220

2.6

--

85.0

940

9.1

--

--

260

1.4

.6

52.6

117

.8

125

.2

241

1.7

1.7

67.2

1,060

7.7

743

1.1

195

1.2

2.2

55.8

1,600

9.0

1,620

1.5

240

1.2

2.3

52.1

972

8.7

1,160

1.7

222

--

--

--

--

--

--

-

~

96 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1997 (Continued)

Constituent

Number of 

composite 

samples

Maxi- ... . «..». Minimum mum

Mean Median

12334510-ROCK CREEK NEAR CLINTON. MONT.

Period of record for biological data: 1987, 1991-97

Arctopsyche grandis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

28

28

28

28

28

28

28

28

.4 .06

2.9 .5

12.3 4.7

991 191

<2.9 .1

454 113

1.6 .2

189 84

.2

1.2

8.3

508

U

244

.8

125

.2

1.0

8.1

436

U

226

.7

122

Claassenia sabulosa

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

15

15

15

15

15

15

15

15

.3 .05

1.8 .4

40.7 18.1

129 49.8

1.0 .1

76.3 15.7

.9 .1

264 164

.2

.8

29.6

89.7

.3

34.7

.3

206

.1

.6

29.3

90.4

.3

32.9

.3

211

Hydropsyche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

3

3

3

3

3

3

3

3

<.2 <.2

1.0 .9

13.1 6.0

609 485

<1.1 <1.1

258 192

.9 .4

99 82

__i

.9

8.6

530

-- 1

219

.6

89

<.2

.9

6.6

497

<1.1

208

.4

86

Hydropsyche occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

4

4

4

4

4

4

4

4

<1.0 <.3

2.4 .9

17.6 9.6

752 520

6.0 1.2

268 169

1.7 .6

144 99

-- 1

1.6

12.0

642

3.0

228

1.2

121

<.3

.9

10.2

648

1.2

215

.9

117

TABLE 24 97
Table 24. Statistical summary of biological data for the upper Clark Fork basin, Montana, August 1986 through 

August 1997 (Continued)

Number of .. .

Constituent composite '" Minimum

samples mum

Mean Median

12334510-ROCK CREEK NEAR CLINTON. MONT.-Continued

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1987, 1991-97

Hydropsyche spp.

2 .3 <.5

2 1.7 . 1.1

2 16.2 15.0

2 1,030 837

2 <3.1 <1.8

2 437 299

2 1.3 .8

2 135 117

'.3

1.4

15.6

932

! --

368

1.0

126

~

-

-

-

-

~

--

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

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1986, 1991-97

Arctopsvche grandis

25 2.7 .6

25 4.1 .6

25 125 20.1

25 2,870 420

25 13.2 2.1

25 893 351

25 2.6 .4

25 276 152

Claassenia sabulosa

20 2.5 .3

20 2.0 .4

20 76.5 38.3

20 181 58.6

20 1.1 .2

20 125 42.0

20 .6 .1

20 283 144

Hydropsyche cockerelli

18 1.7 .6

18 8.0 1.0

18 118 26.4

18 2,530 688

18 12.1 2.2

18 788 426

18 2.6 .6

18 228 148

1.4

1.7

41.7

1,010

4.4

599

1.0

196

1.2

.8

56.0

103

.5

72.1

.2

222

1.0

2.2

52.0

1,260

5.3

578 .

1.2

187

1.2

1.4

28.9

790

3.1

593

.8

187

.9

.6

53.9

101

.6

68.5

.2

232

.8

1.6

40.5

1,060

4.7

549

1.1

180

98 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1997 (Continued)

Number of . 

Constituent composite Minimum 

samples mum

Mean Median

12334550-CLARK FORK AT TURAH BRIDGE. NEAR BONNER. 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: 1986, 1991-97

Hydropsyche morosa group

1

1

1

1

1

1

1

1

Hydropsyche occidentalis

12 1.8 .3

12 3.1 .6

12 102 34.1

12 2,310 472

12 12.2 3.0

12 1,510 454

12 1.9 .6

12 235 145

Hydropsyche spp.

1

1

1

1

\

1

1

1

1.1

4.6

26.8

986

6.6

1,320

1.7

231

.9

1.8

48.8

1,100

5.7

774

1.0

190

1.3

2.4

84.1

1,800

<7.8

537

1.3

171

~

~

--

-

~

--

-

-

.8

1.5

38.7

951

4.7

672

.9

183

-

--

--

--

--

--

-

-

12340000-BLACKFOOT RIVER NEAR BONNER. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

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

Arctopsyche grandis

6 .3 <.l

0

6 17.9 12.1

6 483 108

6 2.1 <.6

0

0

6 366 123

1996

'.2

--

14.3

327

'1.1

-

-

223

'.2

--

13.1

431

1 <1.9

-

--

136

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

August 1997 (Continued)

Number of Maxj 

Constituent composite " Minimum 

samples mum

Mean Median

12340000-BLACKFOOT RIVER NEAR BONNER. 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: 1986-87, 1991, 1993,

Claassenia sabulosa

9 .6 .1

0

9 51.0 32.0

9 199 68.0

9 .6 <.3

0

0

9 233 184

Hvdropsvche occidentalis

9 .5 .1

9 2.1 .8

9 20.6 13.0

9 1,530 1,060

9 1.9 1.1

9 527 414

9 1.8 .9

9 150 123

Hydropsyche spp.

1

1

1

1

1

1

1

1

1996

.4

43.0

116

'.3

-

~

203

.2

1.5

14.9

1,270

1.3

463

1.2

138

.6

1.6

13.9

1,120

2.9

525

2.8

132

.5

44.0

113

<.5

--

--

197

.2

1.5

14.5

1,260

1.6

452

1.2

144

--

--

--

--

--

--

--

--

12340500-CLARK FORK ABOVE MISSOULA. MONT.

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Period of record for biological data: 1997

Arctopsyche grandis

3 1.8 1.2

3 3.0 1.8

3 77.6 40.6

3 2,340 1,360

3 6.8 1.2

3 924 585

3 2.0 1.2

3 235 155

1.4

2.2

54.7

1,690

4.2

725

1.5

188

1.2

1.8

45.8

1,370

4.6

665

1.4

173

100 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

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

August 1997 (Continued)

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Number of _. . 

Constituent composite " Minimum Mean

samples mum

12340500-CLARK FORK ABOVE MISSOULA. MONT.-Continued

Period of record for biological data: 1997

Claassenia sabulosa

2 2.0 1.7 1.8

2 1.1 .5 .8

2 51.0 37.8 44.4

2 136 95.3 116

2 <3.8 <1.4 1 «

2 111 75.2 93.1

2 <.9 <.3 1 --

2 273 226 250

Hvdropsvche cockerelli

3 1.3 1.1 1.2

3 4.1 3.1 3.5

3 96.1 83.5 89.2

3 3,590 2,430 2,890

3 6.3 5.5 6.0

3 878 781 823

3 2.4 1.9 2.2

3 226 207 218

Hvdropsvche occidentalis

1 - - 1.0

1 - -- 2.9

1 -- -- 76.5

1 - -- 2,240

1 - - 7.7

1 - - 939

1 - - 1.9

1 - - 210

12353000-CLARK FORK BELOW MISSOULA. MONT.2

Period of record for biological data: 1986, 1990-97

Arctopsyche grandis

13 1.1 .3 .5

13 2.7 .5 1.3

13 38.0 9.4 19.1

13 1,500 343 714

13 3.2 .9 1.6

13 1,090 511 685

13 1.6 .4 .9

13 169 106 139

Median

--

--

-

~

-

1.1

3.3

88.1

2,650

6.2

809

2.2

220

--

--

--

-

-

-

--

--

.5

1.2

17.1

545

1.4

640

.8

137

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

August 1997 (Continued)

Constituent

Number of 

composite 

samples

Maximum

Minimum Mean Median

123S3000-CLARK FORK BELOW MISSOULA. MONT.2-Continued 

Period of record for biological data: 1986,1990-97

Claassenia sabulosa

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

27

27

27

27

27

27

27

27

1.3

1.2

61.5

240

1.3

168

.3

286

.2

.05

31.1

66.6

.1

48.9

.1

146

.5

.5

46.4

105

.4

98.4

.2

202

.4

.5

46.5

91.9

.3

93.0

.2

200

Hydropsvche cockerelli

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

24

24

24

24

24

24

24

24

.9

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

29.3

1,240

2.2

715

1.2

144

.6

1.9

29.5

1,260

2.0

663

1.2

151

Hydropsvche occidentalis

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

Cadmium

Chromium

Copper

Iron

Lead

Manganese

Nickel

Zinc

9

9

9

9

9

9

9

9

1

1

1

1

1

1

1

1

.9

3.5

38.2

1,420

3.5

1,460

2.2

193

Hydropsvche spp.

-

-

-

~

-

-

.2

.2

18.9

482

.7

667

.5

116

~

--

--

--

~

-

-

-

.4

1.4

25.0

878

1.9

915

1.0

141

.5

.8

20.8

894

1.1

756

1.1

124

.3

1.6

21.0

741

1.9

891

.9

132

-

-

--

--

-

--

--

--

'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. 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.

102 Water-quality, bed-sediment, and biological data (October 1996 through September 1997) and statistical summaries of data for 

streams in the Upper Clark Fork Basin, Montana

3rU.S. GOVERNMENT PRINTING OFFICE:1998-676-285/8J055