Prepared in cooperation with the Montana Department of Environmental Quality

Quantification of Trace-Element Loading 

in the Upper Tenmile Creek Drainage Basin 

near Rimini, Montana, September 2011

Scientific Investigations Report 2019–5126

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the Montana Department of Environmental Quality

Quantification of Trace-Element Loading 

in the Upper Tenmile Creek Drainage Basin 

near Rimini, Montana, September 2011
Cover photo. The Susie Lode adit discharge entering Tenmile Creek near Rimini, 

Montana. Photograph by Craig L. Bowers, U.S. Geological Survey, September 16, 2011.
Quantification of Trace-Element Loading 

in the Upper Tenmile Creek Drainage Basin 

near Rimini, Montana, September 2011

By Tom Cleasby and Sara L. Caldwell Eldridge

Prepared in cooperation with the Montana Department of Environmental Quality

Scientific Investigations Report 2019–5126

U.S. Department of the Interior

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

DAVID BERNHARDT, Secretary

U.S. Geological Survey

James F. Reilly II, Director

U.S. Geological Survey, Reston, Virginia: 2020

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Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Cleasby, T., and Eldridge, S.L.C., 2020, Quantification of trace element loading in the upper Tenmile Creek drainage 

basin near Rimini, Montana, September 2011: U.S. Geological Survey Scientific Investigations Report 2019–5126, 

40 p., https://doi.org/10.3133/sir20195126.

Associated data for this publication:

U.S. Geological Survey, 2016c, USGS water data for the Nation: U.S. Geological Survey National Water Information 

System database, accessed March 14, 2019, at https://doi.org/10.5066/F7P55KJN.

ISSN 2328-0328 (online)
iii

Acknowledgments

This study was conducted through a cooperative agreement with the Montana Department of 

Environmental Quality. Great appreciation is extended to the many people who supported and 

assisted this study. Special thanks to the City of Helena Water Department for their help during 

the study and to the land owners who allowed access to the study site by way of their property. 

Thanks to the employees of CDM-Smith; Neil Marsh, Angela Frandsen, Curt Cover, Dave Swanson, 

and David Shanight for sharing their knowledge and maps of the study area. Also, thanks to 

Mike Bishop of the U.S. Environmental Protection Agency (retired) for his assistance in data 

collection. Thanks to the many people in the U.S. Geological Survey who aided in both office 

and field work.

v

Contents

Acknowledgments........................................................................................................................................iii

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

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

Purpose and Scope ..............................................................................................................................3

Study Area..............................................................................................................................................3

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

Streamflow Estimation.........................................................................................................................8

Surface-Water-Quality Sampling.......................................................................................................9

Groundwater Sampling........................................................................................................................9

Quality Assurance/Quality Control..............................................................................................................9

Quantification of Trace-Element Loading ................................................................................................11

Streamflow...........................................................................................................................................11

Water Quality.......................................................................................................................................18

Surface Water.....................................................................................................................................18

Groundwater........................................................................................................................................23

Quantification of Trace-Element Loading .......................................................................................24

Comparison of Relative Sources and Sinks of Trace-Element Loads 

between 2011 and 1998 ........................................................................................................31

Summary and Conclusions.........................................................................................................................38

References Cited..........................................................................................................................................39

Figures

1. Locations of the study reaches, upper Tenmile Creek, Montana,

1998 and 2011.................................................................................................................................2

2. Locations of surface-water sites and selected mine sites, upper

enmile Creek, Montana, 2011......................................................................................................4

3. Locations of groundwater sites and selected mine sites, upper

Tenmile Creek, Montana, 2011....................................................................................................7

4. Time series of tracer dye concentrations at sites 7 and 24, upper

Tenmile Creek, Montana, 2011..................................................................................................12

5. Streamflow calculated by tracer injection, upper Tenmile Creek

drainage basin, Montana, 1998 and 2011................................................................................17

6. Values of pH measured in main-stem and inflow sites downstream from

the tracer-injection point, upper Tenmile Creek drainage basin, Montana,

1998 and 2011...............................................................................................................................20

7a. Concentrations of A. dissolved cadmium, B. total-recoverable cadmium, 

C. dissolved copper, D. total-recoverable copper, E. dissolved lead,

F. total-recoverable lead, G. dissolved zinc, H. total-recoverable zinc,

I. dissolved arsenic, and J. total-recoverable arsenic measured in main-stem

and inflow sites downstream from the tracer-injection point, upper

Tenmile Creek drainage basin, Montana, 1998 and 2011 .....................................................21
vi

Figures—Continued

7b. Concentrations of A. dissolved cadmium, B. total-recoverable cadmium, 

C. dissolved copper, D. total-recoverable copper, E. dissolved lead,

F. total-recoverable lead, G. dissolved zinc, H. total-recoverable zinc,

I. dissolved arsenic, and J. total-recoverable arsenic measured in main-stem

and inflow sites downstream from the tracer-injection point, upper

Tenmile Creek drainage basin, Montana, 1998 and 2011 .....................................................22

8. Tracer-calculated cadmium loads, upper Tenmile Creek drainage basin,

Montana, September 2011 ........................................................................................................28

9. Tracer-calculated copper loads, upper Tenmile Creek drainage basin,

Montana, September 2011 ........................................................................................................29

10. Tracer-calculated lead loads, upper Tenmile Creek drainage basin,

Montana, September 2011 ........................................................................................................30

11. Tracer-calculated zinc loads, upper Tenmile Creek drainage basin,

Montana, September 2011 ........................................................................................................30

12. Tracer-calculated arsenic loads, upper Tenmile Creek drainage basin,

Montana, September 2011 ........................................................................................................31

Tables

1. Sampled surface-water sites, upper Tenmile Creek drainage basin,

Montana, 2011 ...............................................................................................................................5

2. Sampled groundwater sites, upper Tenmile Creek drainage basin,

Montana, 2011 ...............................................................................................................................6

3. Concentrations of water-quality constituents and the relative percent

differences measured in primary and replicate samples from groundwater

and surface-water sites in the upper Tenmile Creek drainage basin, Montana,

September 2011...........................................................................................................................10

4. Results of streamflow calculated by tracer injection, surface-water inflow,

subsurface inflow, and associated water-quality analyses of samples collected

from upper Tenmile Creek drainage basin, Montana, September 2011 ............................13

5. Groundwater levels and results of water-quality analyses of groundwater

samples collected at wells adjacent to upper Tenmile Creek, Montana,

September 2011...........................................................................................................................19

6. Instantaneous loads of trace elements measured in surface-water samples,

upper Tenmile Creek drainage basin, Montana, September 2011......................................25

7. Instantaneous loads and cumulative instantaneous loads (in micrograms per

second) of total-recoverable trace elements measured in main-stem

surface-water samples, upper Tenmile Creek, Montana, 1998 and 2011..........................33
vii

Conversion Factors

U.S. customary units to International System of Units

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2

) 259.0 hectare (ha)

square mile (mi2

) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L) 

gallon (gal) 0.003785 cubic meter (m3

) 

gallon (gal) 3.785 cubic decimeter (dm3

) 

cubic yard (yd3

) 0.7646 cubic meter (m3) 

Flow rate

foot per second (ft/s) 0.3048 meter per second (m/s)

cubic foot per second (ft3

/s) 0.02832 cubic meter per second (m3/s)

International System of Units to U.S. customary units

Multiply By To obtain

Volume

cubic meter (m3

) 6.290 barrel (petroleum, 1 barrel = 42 gal)

liter (L) 33.82 ounce, fluid (fl. oz)

liter (L) 2.113 pint (pt)

liter (L) 1.057 quart (qt)

liter (L) 0.2642 gallon (gal)

Flow rate

liter per second (L/s) 15.85 gallon per minute (gal/min) 

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

°F = (1.8 × °C) + 32.

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

°C = (°F – 32) / 1.8.

Datum

Horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 27).
viii

Water-Year Definition

Water year is the 12-month period from October 1 through September 30 of the following 

calendar year. The water year is designated by the calendar year in which it ends. For example, 

water year 2011 is the period from October 1, 2010, through September 30, 2011.

Abbreviations

LRL laboratory reporting level

NWIS National Water Information System (U.S. Geological Survey database)

NWQL National Water Quality Laboratory

RPD relative percent difference

SCUFA self-contained underwater fluorescence apparatus

USGS U.S. Geological Survey
Quantification of Trace-Element Loading in the Upper 

Tenmile Creek Drainage Basin near Rimini, Montana, 

September 2011

By Tom Cleasby and Sara L. Caldwell Eldridge

Abstract

The principle sources of trace elements entering upper 

Tenmile Creek, Montana, during September 2011, four trace 

metals and the metalloid arsenic, were identified and quantified by combining and analyzing streamflow data determined 

from tracer injection with trace-element concentrations and 

related water-quality data determined from synoptic sampling. 

The study reach was along upper Tenmile Creek, beginning 

downstream from the city of Helena’s diversion and extending 5,020 feet downstream. Results from the 2011 study, 

completed by the U.S. Geological Survey in cooperation with 

the Montana Department of Environmental Quality, were 

compared to results from a similar study conducted in 1998 to 

assess the effectiveness of mine reclamation and remediation 

work to reduce trace-element loading to upper Tenmile Creek, 

which has been ongoing throughout the drainage basin.

Main-stem concentrations of most trace elements 

analyzed were generally greater in 1998 than in 2011. However, the State of Montana human-health criteria for totalrecoverable cadmium and arsenic were exceeded in parts of 

upper Tenmile Creek, and concentrations of cadmium and zinc 

exceeded the acute aquatic-life criteria at all main-stem sites 

during both studies. Total-recoverable copper concentrations 

observed in 2011 exceeded the chronic aquatic-life criterion 

upstream from the Lee Mountain adit, whereas, in 1998, all 

sites exceeded the acute aquatic-life criteria.

Direct comparison of loads from the 1998 and 2011 tracer 

studies were complicated by the differences in hydrologic 

conditions. Streamflow in 1998 was about 10 percent of the 

2011 streamflow. The Lee Mountain Mine and Susie Lode 

adit were identified as major contributors of trace elements to 

upper Tenmile Creek in both studies. However, trace-element 

loading from the Lee Mountain Mine area was substantially 

reduced between 1998 and 2011. Total-recoverable loads of all 

trace elements showed substantial loss in 1998 but increased 

in 2011 downstream from the Susie Lode adit to the end of 

the study reach. This reach was one of the primary sources of 

trace-element loading to upper Tenmile Creek in 2011. This 

difference indicated that the streambed may act as a sink or a 

source for trace elements, depending on hydrologic conditions.

Introduction

The upper Tenmile Creek drainage basin in west-central 

Montana (defined in this report as that part of the Tenmile 

Creek basin upstream from the Tenmile Water Treatment 

plant), is typical of many headwater areas in the western 

United States where acid drainage from mine lands has 

affected the quality of water and aquatic resources (Parrett 

and Hettinger, 2000). Tailings and other artifacts from more 

than 100 years of mining are scattered throughout the drainage basin (Metesh and others, 1998). Many of these mining 

artifacts are sources of trace-element (trace metals; primarily 

cadmium, copper, lead, iron, zinc, and the metalloid arsenic) 

loads to upper Tenmile Creek (Cleasby and Nimick, 2002). 

In 1998, a trace-element loading study was conducted by the 

U.S. Geological Survey (USGS) using tracer techniques and 

synoptic water-quality samples in a 9.8-mile reach of upper 

Tenmile Creek near Rimini, Montana (fig. 1). Study results 

identified and quantified several substantial trace-element 

loading sources to upper Tenmile Creek in the nearly 1-mile 

subreach that flowed through the town of Rimini (Cleasby and 

Nimick, 2002). In 1999, the U.S. Environmental Protection 

Agency designated upper Tenmile Creek as a Federal superfund site (U.S. Environmental Protection Agency, 2002). Since 

the superfund designation, extensive remediation work has 

been completed throughout the drainage basin with the goal 

of reducing trace-element loading to upper Tenmile Creek. 

Remediation work within the stream reach sampled for this 

study included the removal of more than 50,000 cubic yards 

of contaminated mine waste from the Lee Mountain Mine 

and the Susie Lode and the removal of contaminated soils in 

residential properties and roads in the town of Rimini. The adit 

portals (a horizontal passage leading into a mine for access 

or drainage) for the Lee Mountain Mine and the Susie Lode 

have been opened and rehabilitated, and pilot scale treatment 

options have been explored.

The USGS, in cooperation with the Montana Department 

of Environmental Quality, initiated a study in 2011 to quantify 

trace-element loading in the upper Tenmile Creek drainage 

basin to help assess the effectiveness of mine reclamation 

and remediation work to reduce trace-element loading to 
2 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Rol19-0021_Fig01

12

SILVER WAVE

46°35'00'' 46°35'00''

112°12'30''

112°12'30''

112°17'30''

112°17'30''

46°30'00'' 46°30'00''

Chessman

 Reservoir

Scott

 Reservoir

Poison

Creek

Beaver Creek

Ruby Creek

Tenmile

Creek

Monitor

Creek

Banner

Creek

Tenmile

Creek

Rimini

Walker Creek

Bear

Gulch

DeerCreek

Moose

Creek

Minnehaha

Creek

Creek Spring

CONTINENTAL

DIVIDE

Tenmile water 

treatment plant

Upper Tenmile Creek

 drainage basin boundary

LEWIS

 AND

CLARK

COUNTY

LEE MOUNTAIN

UPPER VALLEY FORGE

SUSIE LODE

RED WATER

LITTLE SAMPSON

BUNKER HILL

LOWER EVERGREEN

BUNKER MILE

ALLEY FRACTION

AVON MILL

W. COYNE

EUREKA

NORTH PACIFIC

Base modified from U.S. Geological Survey digital data, 1:24,000, 1961–89 (streams); 

U.S. Census Bureau digital data, 1:100,000, 1992 (roads) 

Albers Equal Area Conic projection 

Standard, parallels 46°00' N. and 48°00' N.

Central meridian 109° 30' W. 

North American Datum of 1927

Inactive mine or mill site and identifier

EXPLANATION

Location of the 2011 tracer study reach

Location of the 1998 tracer study reach

City diversion

EUREKA

U.S. Geological Survey streamgage 

and identifier 

06062500

06062500

Missouri

River

M O N T A N A

Tenmile Creek

drainage basin

Upper

Tenmile Creek

drainage basin Helena

0 1 2 MILES

0 1 2 KILOMETERS

Figure 1. Locations of the study reaches, upper Tenmile Creek, Montana, 1998 and 2011.
Methods 3

upper Tenmile Creek. The 2011 study was performed using 

tracer injection and synoptic water-quality sample collection 

methods similar to the 1998 study within the approximately 

1-mile subreach where the 1998 study identified substantial 

trace-element loading sources (fig. 2). Data collected in the 

2011 study were used to estimate trace-element loadings from 

various sources in this subreach of the upper Tenmile Creek 

drainage basin and were compared to results of the 1998 traceelement loading study. The two principal objectives of this 

study were (1) to identify and quantify the primary sources of 

trace-element loads entering a 5,020-foot reach of upper Tenmile Creek and (2) to compare the 2011 results (current study) 

with results from the trace-element loading study conducted in 

1998 to describe changes in the sources and overall transport 

of trace-element loads in upper Tenmile Creek after reclamation activity.

Purpose and Scope

The purposes of this report are to present the results of a 

trace-element study completed in September 2011 in the upper 

Tenmile Creek drainage basin and to provide a comparison 

of the 2011 results with results from a previous trace-element 

loading study conducted in 1998. Physical and chemical 

data collected at 19 upper Tenmile Creek main-stem sites, 

8 surface-water inflow sites, and 8 groundwater sites during 

September 13–14, 2011, are presented to describe the loading 

and downstream transport of trace elements in the study reach 

of upper Tenmile Creek. Quality-assurance data are presented 

for samples collected concurrently.

Study Area

Tenmile Creek originates on the eastern side of the Continental Divide and flows about 12 miles toward the Ten Mile 

Water Treatment Plant west of Helena, Mont. (fig. 1), draining 

about 200 square miles of mountain and valley terrain (Parrett 

and others, 2001). The reach of interest for this study starts 

just upstream from Rimini, Mont., about 5 miles downstream 

from the headwaters, and ends just downstream from Rimini. 

With a population of less than 100 people, the Rimini community consists primarily of single-family homes and cottages. Hard-rock mining for gold, lead, copper, and zinc took 

place from the 1870s through the 1930s, and some intermittent 

activity transpired until 1953 (U.S. Environmental Protection 

Agency, 2002). Remnants from the mining take form as acidmine drainage from flowing adits, tailings, and waste-rock 

piles scattered throughout the drainage basin and are potential 

sources of trace-element contamination. Trace elements from 

some of these sources have been mobilized throughout the 

drainage basin by surface-water movement, wind erosion, and 

groundwater leaching. Also, contaminated material has been 

moved from source sites and used as fill along roads and other 

areas within the drainage basin (U.S. Environmental Protection Agency, 2002).

Since the classification of upper Tenmile Creek as a 

superfund site on October 22, 1999, remediation of mining 

sites within the study reach included the removal of waste rock 

from the Lee Mountain Mine adit and the Susie Lode adit. 

Both adits were opened, and experimental treatment of the 

acid-mine drainage water was attempted at each site. 

At the Lee Mountain Mine, the adit discharge was treated 

with lime to increase the pH and precipitate the trace elements 

before entering upper Tenmile Creek. As part of the treatment system at the Lee Mountain Mine, the land surface was 

re-contoured to direct as much of the mine drainage into the 

treatment system as possible. Before remediation, the drainage 

from the mine was diffuse, and discharge from the adit percolated into the ground and, depending on flow paths, traveled a 

considerable distance before seeping into upper Tenmile Creek 

(Cleasby and Nimick, 2002). The passive lime treatment was 

discontinued because of the costly maintenance needed to 

replenish the lime and remove the precipitate from the settling 

ponds. An experimental treatment system at the Susie Lode 

adit operated for a short time. However, this was discontinued 

because the adit was deemed unstable, and the operation of 

the treatment system was unsafe. More recently, waste rock, 

tailings, and fill used for roads and landscaping previously 

suspected of being trace-element loading sources have been 

removed and replaced with clean fill material.

Methods

This study was designed to provide a snapshot of the 

loading and downstream transport of trace elements in the 

study reach. Tracer injection was used to determine streamflow, and synoptic water-quality sampling was used to determine concentrations of trace elements and other constituents.

A reconnaissance of the study reach was conducted 

1 week before the start of the tracer injection. Sites to be 

sampled were selected, marked with flagging, and their 

locations were determined using a handheld global position 

system (table 1, fig. 2) receiver. When possible, sites that 

were sampled in the 1998 trace-element loading study were 

included in the current study. Sampling sites were selected on 

upper Tenmile Creek upstream and downstream from surfacewater inflows, tailing piles, and other mining-related features, 

which might provide trace-element loadings to the creek. 

Eight groundwater monitoring wells were sampled near the 

Lee Mountain Mine to evaluate trace-element loading from 

groundwater to upper Tenmile Creek (table 2, fig. 3). Two 

wells were located on the right bank (looking downstream) 

and six were on the left bank, where most of the disturbances 

from the Lee Mountain Mine were located. Three of the wells 

on the left bank were preexisting and located to the north of 

(downstream from) the Lee Mountain Mine adit (LMLB–4, 

5, and 6). These three wells were installed during reclamation that included the recontouring of the Lee Mountain Mine 

adjacent to the left bank of upper Tenmile Creek (fig. 3). 
4 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Rol19-0021_Fig02

17a

9

8

7

6

5

4

3

2

24

23

22

21

20

19

17 16

14

13

12

11

5.5

1

18

15

10 8.5

6.5

6.75

0

112°15'00'' 112°14'45"

46°29'30"

46°29'15"

46°29'00''

LEE MOUNTAIN

MINE

SUSIE LODE

LITTLE LILY MINE

Base modified from Montana National Agriculture Imagery Program, 2011 

Scale 24-Kilometer tiles, 2012, State Plane coordinate system, Zone 2500 

Standard parallel 45°00' N. and 49°00' N.

Central meridian 109°30' W. 

North American Datum 1983 (NAD 83)

0 0.1 MILE

0 0.1 KILOMETER

Tenmile Creek

Tenmile Creek

Beaver Creek

Moore’s Spring 

Creek

Spring Creek

EXPLANATION

Surface-water main-stem site 

and site number (table 1)

Surface-water inflow site and 

site number (table 1)

Mine site and identifier

14

8

City diversion

Town of 

Rimini

Figure 2. Locations of surface-water sites and selected mine sites, upper Tenmile Creek, Montana, 2011.
Methods 5

Table 1. Sampled surface-water sites, upper Tenmile Creek drainage basin, Montana, 2011.

[Surface-water inflow sites are bold. USGS, U.S. Geological Survey; ft, foot; ab, above; nr, near; bl, below; LB, left bank (looking downstream); 

RB, right bank (looking downstream); ---, number not assigned]

Site number1

(fig. 2) Station description USGS stationidentification number

Distance downstream 

from injection site 

(ft)

0 Tenmile Creek ab City Diversion, nr Rimini, MT2 462853112144101 –50

1 Tenmile Creek bl City Diversion, at Rimini (injection site) 462902112144401 0

2 Tenmile Creek 365 ft bl City Diversion, at Rimini 462902112144101 365

3 Tenmile LB seep 665 ft bl City Diversion, at Rimini 462903112144501 665

4 Tenmile Creek 695 ft bl City Diversion at Rimini 462904112144501 695

5 Tenmile Creek 1,115 ft bl City Diversion, at Rimini 462907112144602 1,115

5.5 Tenmile Creek 1,215 ft bl City Diversion, at Rimini 462909112144501 1,215

6 Tenmile RB discharge pipe 1,245 ft bl City Diversion 462910112144501 1,245

6.5 Tenmile Creek 1,350 ft bl City Diversion, at Rimini 462911112144502 1,350

6.75 Lee Mountain Mine adit discharge, at Rimini 462911112144601 1,400

7 Tenmile Creek 1,780 ft bl City Diversion, at Rimini 462912112144601 1,780

8 LB seep from Lee Mountain Mine2 --- 1,800

8.5 Tenmile Creek RB seep 1,970 bl City Diversion, at Rimini 462914112144702 1,970

9 Tenmile Creek 1,985 ft bl City Diversion, at Rimini 462914112144703 1,985

10 Beaver Creek at mouth, at Rimini 462914112144801 2,000

11 Tenmile Creek 2,120 ft bl City Diversion, at Rimini 462915112144801 2,120

12 Tenmile Creek 2,420 ft bl City Diversion, at Rimini 462917112145001 2,420

13 Tenmile Creek ab Susie Lode Adit, at Rimini 462920112145501 2,765

14 Tenmile Creek 3,015 ft bl City Diversion, at Rimini 462922112145301 3,015

15 Susie Lode Adit discharge at mouth, at Rimini 462923112145301 3,040

16 Tenmile Creek 3,250 ft bl City Diversion, at Rimini 462925112145501 3,250

17 Spring Creek at Mouth, at Rimini 462921112145701 3,305

18 Tenmile Creek 3,415 ft bl City Diversion, at Rimini 462925112145701 3,415

17a Spring Creek Fork2 --- 3,500

19 Tenmile Creek 3,575 ft bl City Diversion, at Rimini 462926112145801 3,575

20 Tenmile Creek 3,850 ft bl Spring Creek, at Rimini 462922112145401 3,850

21 Tenmile Creek 4,180 ft bl City Diversion, at Rimini 462932112150101 4,180

22 Tenmile Creek 4,675 ft bl City Diversion, at Rimini 462935112150401 4,675

23 Moore's Spring Creek at mouth, at Rimini 462932112145801 4,890

24 Tenmile Creek 5,020 ft bl City Diversion, at Rimini 462937112150501 5,020

1

Sites identified as whole numbers were sampled in 1998 and 2011. Sites 5.5, 6.5, and 6.75 were only sampled in 2011. Site 17a is a fork of 

Spring Creek and was not sampled. Streamflow at 17a was combined with site 17 streamflow for load calculations. 

2

Not sampled in 2011.

The preexisting wells were constructed of 4-inch diameter 

polyvinyl chloride casing and were perforated along their 

entire length. Five wells, LMRB–1, LMRB–2, LMLB–1, 

LMLB–2, and LMLB–3, were hand-driven near upper Tenmile Creek (fig. 3). The large boulder substrate in the area 

constrained the locations of the hand-driven wells, and several 

attempts were made before the final wells were successfully 

installed. The new wells were constructed with 1.25-inch 

diameter galvanized pipe with perforations over the lower 

0.1-foot of the pipe (just above the drive point). The six 

wells on the left bank were located downgradient from the 

Lee Mountain Mine adit.
6 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Table 2. Sampled groundwater sites, upper Tenmile Creek drainage basin, Montana, 2011.

[USGS, U.S. Geological Society; ft, foot; in., inch; PVC, polyvinyl chloride]

Site

number1

(fig. 3)

USGS station 

identification 

number

Distance 

downstream 

from injection 

site (ft)

Well

depth

(ft)

Open 

interval 

top (ft)

Water 

level

(ft)

Remarks

Right stream bank wells1

LMRB–1 462907112144601 1,115 3.9 3.7 2.20 85 ft from Tenmile Creek, 380 ft upstream from bridge, 

1.25-in. diameter galvanized casing.

LMRB–2 462911112144501 1,700 5.3 5.1 1.12 50 ft from Tenmile Creek, 20 ft upstream from bridge, 

1.25-in. diameter galvanized casing.

Left stream bank wells1

LMLB–1 462908112144601 1,145 9.5 9.3 6.89 10 ft from Tenmile Creek 380 ft upstream from bridge, 

1.25-in. diameter galvanized casing.

LMLB–2 462909112144701 1,400 9.4 0 3.56 Near adit, 80 ft from Tenmile Creek, 220 ft upstream 

from bridge, 4-in. diameter PVC casing.

LMLB–3 462910112144601 1,600 13.3 0 8.04 135 ft from Tenmile Creek, 150 ft upstream from bridge, 

4-in. diameter PVC casing.

LMLB–4 462913112144801 2,000 9.5 0 0.65 50 ft from Tenmile Creek, 200 ft downstream from 

bridge, located in shallow pit, 4-in. diameter PVC 

casing.

LMLB–5 462913112144701 2,000 4.3 4.1 0.51 Near Tenmile Creek, 200 ft downstream from bridge, 

1.25-in. diameter galvanized casing.

LMLB–6 462914112144701 2,100 4.9 4.7 0.90 Near Tenmile Creek, 250 ft downstream from bridge, 

1.25-in. diameter galvanized casing.

1

Left-bank and right-bank designations refer to Tenmile Creek.
Methods 7

Rol19-0021_Fig03

LMLB–6

LMLB–5

LMLB–4

LMLB–3

LMLB–2

LMLB–1

LMRB–2

LMRB–1

LEE MOUNTAIN

MINE

LITTLE LILY MINE

LITTLE LILY MINE

LEE MOUNTAIN ADIT

0 0.05 0.1 MILE

0 0.05 0.1 KILOMETER

EXPLANATION

Groundwater site and site number

Mine site and identifier

LMLB–4

Base modified from Montana National Agriculture Imagery Program, 2011 

Scale 24-Kilometer tiles, 2012, State Plane coordinate system, Zone 2500 

Standard parallel 45°00' N. and 49°00' N.

Central meridian 109°30' W.

North American Datum 1983 (NAD 83)

5

5

112°15'00'' 112°14'45"

46°29'15"

46°29'08" Beaver Creek

Spring Creek

Tenmile Creek

Tenmile Creek

Surface-water site, main stem 

and site number (table 1)

Figure 3. Locations of groundwater sites and selected mine sites, upper Tenmile Creek, Montana, 2011. 
8 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Streamflow Estimation

Streamflow can be determined using tracer injection and 

dilution. Streamflow measurements by tracer injection are 

recommended only for those sites where conventional methods cannot be accurately applied owing to shallow depths, 

extremely high velocities, excessive turbulence, or excessive 

hyporheic flow (Kilpatrick and Cobb, 1984). These conditions

were present within the study reach of upper Tenmile Creek. 

Streamflow cannot be determined using tracer injection and 

dilution in a losing stream reach because the tracer concentration would remain constant through flow decreases. Tracer 

injection using Rhodamine WT dye as the tracer (Kilpatrick 

and Cobb, 1984; Wilson and others, 1986; Kimball, 1997; 

Cleasby and others, 2000; Cleasby and Nimick, 2002) was 

used to calculate streamflow. The tracer-injection rate, a tracer

solution dilution factor, and instream concentrations of the 

tracer at equilibrium were required to calculate streamflow at 

any location downstream from the injection point.

A tracer solution was prepared in a 50-gallon barrel 

by mixing 0.5-liters of Rhodamine WT dye (stock solution 

2.0×108

 micrograms per liter [μg/L]) with about 140 liters of 

stream water before the tracer injection. Starting at 7:10 a.m. 

on September 13, 2011, and ending at 12:30 p.m. on September 14, 2011, this solution was injected continuously into 

upper Tenmile Creek surface-water sites at a rate of 92 milliliters per minute (0.00153 liters per second [L/s]) using a 

positive-displacement metering pump system. During the 

injection, three samples were collected from the premixed 

tracer solution to document the relative dye concentration in 

the injected tracer solution. These samples were collected in 

glass bottles and stored out of direct sunlight in a dark cooler. 

Samples were transported to the USGS Wyoming-Montana 

Water Science Center (Helena, Mont.), where they were 

diluted serially using de-ionized water. The diluted tracer 

samples were then analyzed with the stream samples using a 

Turner Design 10A bench fluorometer.

Throughout synoptic sampling and the tracer injections, 

instream dye concentrations were monitored continuously 

at two sites (7 and 24, fig. 2) downstream from the injection 

point to document the movement and equilibrium concentrations of the injected dye. At each tracer monitoring site, a 

calibrated self-contained underwater fluorescence apparatus 

(SCUFA) was placed near the centroid of streamflow. SCUFAs were programmed to measure and log dye concentrations

every 10 minutes.

Additional streamflow measurements were made at 

selected upper Tenmile Creek sites and at all surface-water 

inflow sites using either traditional current-meter measurements (Rantz and others, 1982) or volumetric measurements 

using a calibrated collection container and stopwatch as 

described in Buchanan and Somers (1969).

For a continuous tracer injection to yield accurate results

the mass of the tracer must be conserved as it moves downstream. The duration of the injection must be enough to allow

tracer concentrations to achieve an equilibrium or plateau 

-

, 

throughout the entire study reach. Also, the reach length 

must be enough for complete lateral mixing of the dye. Once

equilibrium plateau concentrations have been achieved through 

the entire reach, streamflow at any site downstream from the 

injection point can be calculated from the conservation of mass 

equation (eq. 1):

 qC=Qc (1)

where

q is the tracer-injection rate, in liters per second, 

and is assumed to be very small relative to 

Q;

C is the concentration of the injected tracer 

solution, in milligrams per liter. This is 

assumed to be large relative to c;

Q is the streamflow, in liters per second; and

c is the resulting plateau concentration of the 

tracer in the stream after dilution by Q in 

milligrams per liter.

Concentrations of C and c in equation 1 can be measured 

in any consistent concentration unit because C/c is a ratio (the 

units cancel out). To evaluate the relative concentrations of C

and c, an injectate sample was retained from the mixed tracer 

solution. A three-step serial dilution was performed on the 

sample of the injectate tracer solution (C) by dilution to concentrations about equal to what was expected in the stream (c). 

The diluted injectate sample was analyzed at the same time as 

the stream sample, using the same fluorometer, and in the same 

laboratory conditions as the stream samples to cancel or minimize errors. This relative comparison method prevented errors, 

given that the concentration of the injectate solution was not 

known precisely. The relative ratio of fluorometer dial readings 

for the diluted injectate sample compared to the stream samples 

were used to calculate streamflow using equation 2:

Q=q (2) R

r x 1

D

where

Q is streamflow, in liters per second;

q is the tracer-injection rate, in liters per second;

R is the net fluorometer dial reading of the 

diluted injectate sample;

r is the net fluorometer dial reading of the 

stream samples; and

D is the dilution of the injectate sample.

The three-step serial dilution was conducted by diluting 

the injectate tracer solution by a factor of 2.052x10-5. 

The diluted sample was then analyzed simultaneously with 

the stream samples using the same fluorometer settings. 

The net fluorometer dial reading for the diluted injectate 

sample was 15.9.
Quality Assurance/Quality Control 9

Surface-Water-Quality Sampling

Synoptic water-quality samples were collected at 19 mainstem sites in upper Tenmile Creek and at 8 surface-water inflow 

sites on September 14, 2011, between 8:00 a.m. and 11:15 a.m. 

after the dye reached an equilibrium plateau as determined by the 

deployed SCUFAs. Two sampling crews collected water samples 

in an upstream direction. One crew started from the center of the 

study reach and worked toward the top of the study reach, and the 

other crew started at the bottom of the study reach and worked 

toward the middle of the study reach. Dip samples were collected 

at each site by dipping sample bottles at a single vertical near the 

centroid of streamflow (U.S. Geological Survey, 2006). Samples 

were processed, filtered, and preserved as described in Ward and 

Harr (1990), Horowitz and others (1994), and U.S. Geological 

Survey (variously dated). Quality assurance for processing waterquality samples was performed as described by U.S. Geological 

Survey (variously dated) and Lambing (2006). Onsite measurements of pH, specific conductance, and water temperature 

were made during collection of water samples according to the 

U.S. Geological Survey (variously dated). Onsite sample processing, including filtration and preservation, was completed according to procedures described by Ward and Harr (1990), Horowitz 

and others (1994), and the U.S. Geological Survey (variously 

dated).Water samples were analyzed for calcium, magnesium, 

and selected trace-element concentrations at the USGS National 

Water Quality Laboratory (NWQL) in Denver, Colorado, using 

methods described by Fishman (1993), Garbarino and Struzeski 

(1998), Hoffman and others (1996), and Garbarino and others 

(2006). Tracer concentrations were determined at the USGS 

laboratory in Helena, Mont., using a Turner Design 10A bench 

fluorometer following methods described in Wilson and others 

(1986).

Groundwater Sampling

Groundwater levels in each well were measured according 

to Cunningham and Schalk (2011) before sampling, and adjacent 

stream levels were marked for follow-up elevation surveys to 

document the gradient between groundwater and surface water 

at the time of sampling. The elevation of the wells and marked 

stream levels were surveyed using standard-differential leveling 

methods (Kenney, 2010).

Groundwater samples were collected from eight shallow 

wells on September 13, 2011, 1 day before the surface-water 

samples were collected. Before sampling, wells with enough 

water were purged using a peristaltic pump by evacuating three 

casing volumes of water. Low-yielding wells were pumped dry 

and allowed to recover. Sampling was performed as described 

by U.S. Geological Survey (variously dated). Groundwater 

samples were analyzed for water temperature, specific conductance, and pH following methods by U.S. Geological Survey 

(variously dated). Groundwater samples were analyzed for dissolved concentrations of calcium, magnesium, and selected trace 

elements at the NWQL using methods described previously for 

surface-water samples.

Quality Assurance/Quality Control

Data collection and analytical procedures used in this 

study incorporated practices designed to control, verify, and 

assess bias and variability in data that resulted from the collection, processing, shipping, and handling of samples. Qualityassurance procedures used for the collection and field processing of water samples were as described by Ward and Harr 

(1990), Horowitz and others (1994), Edwards and Glysson 

(1999), Lambing (2006), and the U.S. Geological Survey (variously dated). Standard procedures used by the NWQL for internal sample handling and quality assurance were as described 

by Friedman and Erdmann (1982), Jones (1987), 

and Pritt and Raese (1995).

Analytical results reported for primary (environmental) 

water samples were evaluated using quality-control samples 

collected and analyzed concurrently with primary samples. 

These quality-control samples consisted of three sets of sequential replicate samples and one blank sample (inorganic blank 

water; de-ionized water that was laboratory produced and that 

carries a certificate of analyte concentrations for each grade and 

lot of water produced) to provide quantitative information on 

the precision and bias of the overall field and laboratory processes. The total number of quality-control samples represented 

about 10 percent of the total number of all samples.

Precision of analytical results is affected by numerous 

sources of potential variability within the field and laboratory 

environments, including sample collection, sample processing, and sample analysis. To assess this variability, sequential 

replicate samples were collected and processed immediately 

after collecting the primary samples from the same site and 

were subjected to identical laboratory analyses as the primary 

samples. The relative percent differences (RPD) between the 

primary (sample 1) and replicate (sample 2) samples were 

calculated using equation 3:

Q=q

R

r x 1

D

RPD=|(sample 1−sample 2)/ / |(sample 1+sample 2) 2| |*100

Two surface-water replicates and one groundwater replicate were collected. RPDs were calculated for each constituent pair (31 total) and are reported in table 3. RPDs for most 

constituents were less than 20 percent and did not preclude 

the use of the data. Four out of 31 replicate pairs for filtered 

constituents showed RPDs greater than 20 percent, 3 of which 

occurred from 1 replicate pair. At surface-water site 24, the 

RPDs for dissolved copper, lead, and arsenic were 23.6 percent, 

74.4 percent, and 67.3 percent, respectively. At groundwater 

site LMRB–1, the RPD for dissolved lead was 50.0 percent. 

All replicate pairs with RPDs exceeding 20 percent were 

re-analyzed, and the differences between sample concentrations 

were confirmed.

A field blank sample (inorganic blank water) was analyzed 

to identify the presence and magnitude of contamination that 

could bias analytical results. Field blanks were collected and 

processed in the same manner and using the same equipment 

as the environmental samples. A field blank with constituent 
10 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Table 3. Concentrations of water-quality constituents and the relative percent differences measured in primary and replicate 

samples from groundwater and surface-water sites in the upper Tenmile Creek drainage basin, Montana, September 2011.

[mg/L, milligram per liter; μg/L, microgram per liter]

Constituent Primary sample Replicate sample Relative percent difference

Site LMRB–11 

Calcium, dissolved, mg/L 9.59 9.65 0.62

Magnesium, dissolved, mg/L 2.29 2.27 0.88

Cadmium, dissolved, μg/L 1.04 1.03 0.97

Copper, dissolved, μg/L 2.1 2.1 0.00

Lead, dissolved, μg/L 0.20 0.12 50.00

Zinc, dissolved, μg/L 379 354 6.82

Arsenic, dissolved, μg/L 4.80 4.80 0.00

Site 6.751

Calcium, dissolved, mg/L 215 220 2.30

Magnesium, dissolved, mg/L 54.6 55.0 0.73

Cadmium, dissolved, μg/L 313 368 16.15

Cadmium, total-recoverable, μg/L 299 297 0.67

Copper, dissolved, μg/L 219 223 1.81

Copper, total-recoverable, μg/L 299 309 3.29

Lead, dissolved, μg/L 22.1 20.2 8.98

Lead, total-recoverable, μg/L 26.6 27.8 4.41

Zinc, dissolved, μg/L 67,900 64,500 5.14

Zinc, total-recoverable, μg/L 57,100 56,700 0.70

Arsenic, dissolved, μg/L 544 581 6.58

Arsenic, total-recoverable, μg/L 646 636 1.56

Site 241

Calcium, dissolved, mg/L 12.9 13.2 2.30

Magnesium, dissolved, mg/L 3.65 3.7 1.36

Cadmium, dissolved, μg/L 8.11 7.98 1.62

Cadmium, total-recoverable, μg/L 7.84 7.84 0.00

Copper, dissolved, μg/L 12.3 9.7 23.64

Copper, total-recoverable, μg/L 26.6 26.4 0.75

Lead, dissolved, μg/L 1.07 0.49 74.36

Lead, total-recoverable, μg/L 3.56 3.55 0.28

Zinc, dissolved, μg/L 1,410 1,260 11.24

Zinc, total-recoverable, μg/L 1,170 1,170 0.00

Arsenic, dissolved, μg/L 45.7 22.7 67.25

Arsenic, total-recoverable, μg/L 110 108 1.83

1

Site numbers are defined on tables 1 and 2.
Quantification of Trace-Element Loading 11

concentrations equal to or less than the laboratory reporting 

limit (LRL) for the analytical method indicates that the entire 

process of sample collection, field processing, and laboratory 

analysis is presumably free of contamination. In the 2011 study, 

one field blank sample was collected at surface-water site 13. 

Trace-element concentrations in this sample were less than the 

LRL except for total-recoverable arsenic (0.12 μg/L), which 

had an LRL of 0.10 μg/L. Because the arsenic concentration in 

the blank sample was near the LRL and was much less than the 

concentrations in all the environmental samples, it is assumed 

that no substantial bias was present in the environmental 

samples.

In addition to the use of quality-control samples submitted from the field, internal quality-assurance practices were 

performed systematically by the NWQL to provide quality 

control of analytical procedures in the laboratory (Pritt and 

Raese, 1995; Maloney, 2005). These internal practices include 

analyses of quality-control samples, such as calibration with 

standard samples, standard reference water samples, replicate 

samples, blank samples, or spiked samples at a proportion 

equivalent to at least 10 percent of the total number of collected 

samples. The NWQL participates in a blind sample program in 

which 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 number of collected samples (https://bqs.usgs.gov/). The 

laboratory also participates in external evaluation studies and 

audits with the National Environmental Laboratory Accreditation Program, U.S. Environmental Protection Agency, Environment Canada, and the USGS Branch of Quality Systems to 

assess analytical performance. Dissolved zinc at most sites in 

the current study exceeded the total-recoverable concentrations 

by as much as 20 percent. This anomaly may be due to matrix 

interference (a shift in analytical results caused by specific constituents, chemical components, or physicochemical properties 

in the matrix). The differences in the measured concentrations 

are usually within precision of the analytical methods. As such, 

it is assumed that most of the zinc is dissolved.

Quantification of Trace-Element 

Loading

Synoptic streamflow and concentrations of water-quality 

constituents are essential to develop a mass loading profile 

along a stream reach. Such a profile can reveal notable spatial 

differences in loads, identify the location of constituent sources, 

and indicate where geochemical reactions affect instream 

concentrations and loads. Load is the product of streamflow and 

constituent concentration, so accurate load estimations require 

accurate streamflow measurements. Using tracer injection to 

determine streamflow is a good alternative to traditional currentmeter methods, which are hampered by irregular channel cross 

sections or turbulent flow typical of many mountain streams and 

do not account for shallow hyporheic flow. Another advantage 

of the tracer-injection method is that the information needed 

to calculate streamflow can be collected more quickly than 

individual current-meter measurements, minimizing potential 

fluctuations in streamflow and trace-element concentrations that 

can occur diurnally and complicate loading calculations.

Streamflow

Tracer-dye concentration data, collected continuously 

with the SCUFAs at surface-water sites 7 and 24 (1,780 and 

5,020 feet (ft) downstream from the tracer-injection point), 

were used to graphically display the temporal variation of dye 

concentrations during the tracer injection as the dye moved 

downstream (fig. 4). Ideally, these graphs have three distinct 

periods that show the arrival, plateau, and departure of the 

injected tracer.

A generally stable plateau concentration indicates that 

the injected dye has reached equilibrium at a downstream site. 

As the tracer moves downstream during the plateau period, 

it becomes diluted by inflows. Therefore, in a gaining stream 

system, the magnitude of the plateau concentration decreases 

downstream as the instream flow increases. Tracer concentration 

data collected at sites 7 and 24 in this study were used to document that a relatively stable plateau concentration was reached 

before the collection of synoptic samples (fig. 4). Changes in 

tracer concentrations were observed during the plateau period 

possibly due to natural streamflow variations, changes in the 

tracer-injection rate, or measurement variability. Streamflow 

data from USGS streamgage 06062500 (U.S. Geological Survey, 2016) indicated that streamflow variations did occur during 

the study period, but it is likely that other factors also contributed to the observed changes in plateau concentrations.

Mean travel times through the upper Tenmile Creek system 

computed from the dye tracer response curve (fig. 4) indicated that the tracer achieved plateau concentrations at the two 

tracer-monitoring sites relatively quickly. Dye concentrations 

at surface-water site 7, which was 1,780 ft downstream from 

the injection point, reached a stable plateau in approximately 

100 minutes and traveled at a mean rate of 0.30 feet per second. 

Plateau concentrations at surface-water site 24, which was 

5,020 ft downstream from the injection point, were measured 

in about 240 minutes after the injection was initiated, and the 

mean travel time at this site in the lower reach was 0.35 feet per 

second. At 5,020 ft downstream from the injection point, the 

mean travel time for the entire study reach was about 0.35 feet 

per second. After termination of the tracer injections at sites 7 

and 24, the times needed to reach the near baseline tracer concentrations were like the arrival times. However, the lingering 

presence of small dye concentrations at both sites indicated 

that some dye was being retained in slower moving pools or in 

hyporheic zones within the study reach.

Streamflow during the 2011 study was determined using 

the results of the fluorometric dial readings for dye samples 

collected at the 19 main-stem sites during the synoptic sampling 

and equation 3 (table 4; fig. 5). Streamflow data collected during 

the 1998 and 2011 trace-element loading studies are presented 

on figure 5 for comparisons.
12 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Rol19-0021_fig04

EXPLANATION

Site 7 (1,780 feet downstream from injection site) Site 24 (5,020 feet downstream from injection site) 

September 13, 2011 

12:00 p.m. 

September 14, 2011

12:00 p.m. 

September 14, 2011

 12:00 a.m. 

September 15, 2011

12:00 a.m. 

Date and time

Dye concentration, in micrograms per liter

20

Synopticsampling

period

terminated

Injection Injection

started

5

10

0

15

Figure 4 Time series of tracer dye concentrations at sites 7 and 24, upper Tenmile Creek, Montana, 2011.

In the 5,020-ft study reach, streamflow increased in 

upper Tenmile Creek from 57.8 L/s at the tracer-injection 

point (site 1) to 96.4 L/s at the end of the study reach (site 24), 

an increase of 38.6 L/s. Total surface inflows accounted for 

5.75 L/s, or about 15 percent of the increase, leaving 32.9 L/s 

of the increase attributable to subsurface inflow. The largest increase in streamflow (12.3 L/s) occurred between sites 

5.5 and 6.5 just upstream from the Lee Mountain Mine adit 

discharge. Although surface inflow at site 6 entered the creek 

between these main-stem sites, surface inflow accounted 

for only 0.057 L/s. The historic confluence of Beaver Creek 

and upper Tenmile Creek was once located in this area of 

large subsurface inflow. The Beaver Creek channel has since 

been moved and now flows parallel to upper Tenmile Creek 

for about 800 ft to its confluence with upper Tenmile Creek 

(surface-water inflow site 10). A berm composed of large 

cobbles and boulders was constructed along this 800-ft reach 

between Beaver Creek and upper Tenmile Creek; however, 

it is possible that substantial subsurface flows took place 

through the berm substrate. Site reconnaissance for the 2011 

study indicated that surface flow was only in the lower 100 ft 

of Beaver Creek, indicating that upstream inflows to Beaver 

Creek were all subsurface flows.

Instantaneous streamflow was measured by current meter 

at four main-stem sites during synoptic sample collection. 

Three of these measurements were made at sites within the 

tracer study reach to confirm the streamflow calculated by 

tracer injection. Instantaneous streamflow also was measured 

at a main-stem site (surface-water site 0; table 1) just upstream 

from the city diversion to estimate flow diverted between 

surface-water sites 0 and 1 to the Ten Mile Water Treatment 

Plant and to calculate trace-element loads in upper Tenmile 

Creek upstream from the city diversion.

Current-meter measurements conducted near the top and 

middle of the study reach (surface-water sites 5 and 12) were 

both within 10 percent of the streamflow calculated by tracer 

injection (table 4), indicating agreement between the two 

methods and possibly a lack of hyporheic flow in the top and 

middle sections. The current-meter measurement conducted 

at the bottom of the study reach (surface-water site 24) was 

about 21 percent less than the tracer-calculated value. Because 

current-meter measurements do not measure hyporheic flow, 

the difference between the two methods indicated that there 

was more hyporheic flow near the bottom of the study reach. 

At the lower end of the reach, about 21 percent of the streamflow was subsurface hyporheic flow.
Quantification of Trace-Element Loading 13

Table 4. Results of streamflow calculated by tracer injection, surface-water inflow, subsurface inflow, and 

associated water-quality analyses of samples collected from upper Tenmile Creek drainage basin, Montana, 

September 2011.

[Subsurface inflows were assigned point of inflow but occurred between upstream and downstream points within the reach. Sites were 

assigned short numbers (Site number), defined in table 1, and displayed on figure 2. Surface-water inflow sites are bold. ft, foot; mg/L, milligram per liter; L/s, liter per second; μS/cm, microseimen per centimeter; CaCO3, calcium carbonate; μg/L, microgram per liter; ab, above; 

nr, near; --, no data; bl, below; E, estimated; LB, left bank (looking downstream); RB, right bank (looking downstream); <, less than]

Site

Distance 

downstream 

from 

injection site 

(ft)

Station description

Dye concentration 

(mg/L)

Tracercalculated 

streamflow 

(L/s) 

0 –50 Tenmile Creek ab City Diversion, at Rimini (36u) -- --

1 0 Tenmile Creek bl City Diversion, at Rimini (injection site)1 20.1 E57.8

2 365 Tenmile Creek 365 ft bl City Diversion, at Rimini 20.5 57.8

3 665 Tenmile LB seep 665 ft bl City Diversion, at Rimini -- --

4 695 Tenmile Creek 695 ft bl City Diversion at Rimini 20.0 59.3

5 1,115 Tenmile Creek 1,115 ft bl City Diversion , at Rimini 19.8 59.9

5.5 1,215 Tenmile Creek 1,215 ft bl City Diversion, at Rimini 19.8 59.9

6 1,245 Tenmile RB discharge pipe 1,245 ft bl City Diversion -- --

6.5 1,350 Tenmile Creek 1,350 ft bl City Diversion, at Rimini 16.4 72.3

6.75 1,400 Lee Mountain Mine adit discharge, at Rimini -- --

7 1,780 Tenmile Creek 1,780 ft bl City Diversion, at Rimini 16.2 73.2

8 1,800 LB seep from Lee Mountain Mine -- --

8.5 1,970 Tenmile Creek RB seep 1,970 bl City Diversion, at Rimini -- --

9 1,985 Tenmile Creek 1,985 ft bl City Diversion, at Rimini2 15.0 E73.6

10 2,000 Beaver Creek at mouth, at Rimini -- --

11 2,120 Tenmile Creek 2,120 ft bl City Diversion, at Rimini 16.0 74.1

12 2,420 Tenmile Creek 2,420 ft bl City Diversion, at Rimini 15.9 74.6

13 2,765 Tenmile Creek ab Susie Lode Adit, at Rimini 15.2 78.0

14 3,015 Tenmile Creek 3,015 ft bl City Diversion, at Rimini 15.1 78.5

15 3,040 Susie Lode Adit discharge at mouth, at Rimini -- --

16 3,250 Tenmile Creek 3,250 ft bl City Diversion, at Rimini 14.5 81.8

17 3,305 Spring Creek at Mouth, at Rimini -- --

18 3,415 Tenmile Creek 3,415 ft bl City Diversion, at Rimini 14.1 84.1

17a 3,500 Spring Creek Fork2 -- --

19 3,575 Tenmile Creek 3,575 ft bl City Diversion, at Rimini 14.0 84.7

20 3,850 Tenmile Creek 3,850 ft bl Spring Creek, at Rimini 13.1 90.5

21 4,180 Tenmile Creek 4,180 ft bl City Diversion, at Rimini 13.1 90.5

22 4,675 Tenmile Creek 4,675 ft bl City Diversion, at Rimini 12.9 91.9

23 4,890 Moore's Spring Creek at mouth, at Rimini -- --

24 5,020 Tenmile Creek 5,020 ft bl City Diversion, at Rimini 12.3 96.4

1

A tracer-calculated streamflow could not be determined at this site because the dye was not fully mixed in Tenmile Creek. A streamflow 

value equal to the value at site 2 was used.

2

The dye concentration at this site was anomalous; therefore, an estimated streamflow value equal to site 7 plus one-half of the difference 

from sites 7 to 11 was assigned to this site.

3

Streamflow (0.23 L/s) at this site, a fork of Spring Creek, was added to site 17 to calculate loads for Spring Creek.
14 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Table 4. Results of streamflow calculated by tracer injection, surface-water inflow, subsurface inflow, and 

associated water-quality analyses of samples collected from upper Tenmile Creek drainage basin, Montana, 

September 2011.—Continued

[Subsurface inflows were assigned point of inflow but occurred between upstream and downstream points within the reach. Sites were 

assigned short numbers (Site number), defined in table 1, and displayed on figure 2. Surface-water inflow sites are bold. ft, foot; mg/L, milligram per liter; L/s, liter per second; μS/cm, microseimen per centimeter; CaCO3, calcium carbonate; μg/L, microgram per liter; ab, above; 

nr, near; --, no data; bl, below; E, estimated; LB, left bank (looking downstream); RB, right bank (looking downstream); <, less than]

Site

Current 

meter 

streamflow 

(L/s)

Surface 

inflow 

(volumetric, 

L/s)

 Subsurface 

inflow

(calculated, 

L/s)

Sample

start

time

pH

(standard 

units)

Specific 

conductance 

(μS/cm)

Calcium, 

dissolved 

(mg/L)

0 83.5 -- -- -- -- -- --

1

1 -- -- -- 1115 6.8 75 7.82

2 -- -- -- 1100 6.9 75 7.98

3 -- 0.057 1.44 1050 6.5 85 8.29

4 -- -- -- 1045 7.2 76 7.75

5 64.8 -- -- 1035 6.9 76 7.83

5.5 -- -- -- 1020 6.9 77 7.82

6 -- 0.057 12.3 1100 8.1 3,070 16.3

6.5 -- -- -- 0955 6.8 79 8.06

6.75 -- 0.41 0.49 0945 2.9 2,230 215

7 -- -- -- 0925 6.8 91 9.35

8 -- -- -- -- -- -- --

8.5 -- 0.085 0.32 0910 6.4 103 10.3

2

9 -- -- -- 0855 6.7 92 9.53

10 -- 0.028 0.47 0845 6.8 113 11.0

11 -- -- -- 0835 6.6 95 9.63

12 71.4 -- -- 0820 6.7 98 10.2

13 -- -- -- 1010 6.6 95 9.89

14 -- -- -- 1000 6.6 97 10.3

15 -- 0.91 2.39 0955 3.3 1,930 155

16 -- -- -- 0945 6.6 123 12.1

17 -- 3.26 2.34 0940 6.7 44 3.81

18 -- -- -- 0930 6.4 119 11.3

3

17a -- 0.23 0.37 -- -- -- --

19 -- -- -- 0915 6.6 119 11.5

20 -- -- -- 0905 6.4 120 11.6

21 -- -- -- 0850 6.9 123 11.6

22 -- -- -- 0840 6.8 127 12.1

23 -- 0.71 3.79 0825 7.3 227 24.1

24 76.5 -- -- 0800 6.8 138 12.9

1

A tracer-calculated streamflow could not be determined at this site because the dye was not fully mixed in Tenmile Creek. A streamflow 

value equal to the value at site 2 was used.

2

The dye concentration at this site was anomalous; therefore, an estimated streamflow value equal to site 7 plus one-half of the difference 

from sites 7 to 11 was assigned to this site.

3

Streamflow (0.23 L/s) at this site, a fork of Spring Creek, was added to site 17 to calculate loads for Spring Creek.
Quantification of Trace-Element Loading 15

Table 4. Results of streamflow calculated by tracer injection, surface-water inflow, subsurface inflow, and 

associated water-quality analyses of samples collected from upper Tenmile Creek drainage basin, Montana, 

September 2011.—Continued

[Subsurface inflows were assigned point of inflow but occurred between upstream and downstream points within the reach. Sites were 

assigned short numbers (Site number), defined in table 1, and displayed on figure 2. Surface-water inflow sites are bold. Abbreviations: 

ft, feet; mg/L, milligrams per liter; L/s, liters per second; μS/cm, microseimens per centimeter; CaCO3, calcium carbonate; μg/L, micrograms 

per liter; ab, above; nr, near; --, no data; bl, below; E, estimated; LB, left bank (looking downstream); RB, right bank (looking downstream); 

<, less than]

Site Magnesium, 

dissolved (mg/L)

Hardness, 

dissolved 

(mg/L as 

CaCO3

) 

Cadmium, dissolved (μg/L)

Cadmium, total 

recoverable 

(μg/L)

Copper, 

dissolved (μg/L)

Copper, total 

recoverable 

(μg/L)

0 -- -- -- -- -- --

1

1 1.80 26.9 1.22 1.22 2.63 3.09

2 1.83 27.5 1.22 1.20 2.72 3.09

3 1.98 28.8 0.56 0.53 2.51 2.76

4 1.80 26.8 1.18 1.16 2.57 3.11

5 1.83 27.1 1.19 1.15 2.64 2.97

5.5 1.83 27.1 1.18 1.15 2.53 2.92

6 4.76 60.3 1.42 1.96 <1.0 323

6.5 1.86 27.8 1.15 1.06 2.45 2.70

6.75 54.6 761 313 299 219 299

7 2.15 32.2 2.77 2.56 4.33 5.50

2

8 -- -- -- -- -- --

8.5 2.71 36.9 1.23 1.08 6.34 8.55

2

9 2.23 33.0 2.75 2.55 4.38 5.86

10 2.99 39.9 0.62 0.54 7.21 9.12

11 2.23 33.2 3.15 2.85 5.54 7.11

12 2.38 35.2 3.38 2.81 5.76 7.59

13 2.34 34.3 2.99 2.78 5.69 7.88

14 2.38 35.6 3.06 2.84 5.22 7.74

15 60.5 636 506 476 1,520 1,490

16 3.24 43.5 8.73 8.54 13.3 28.1

17 1.03 13.7 0.85 0.87 6.53 8.33

18 3.09 41.1 6.77 8.05 5.30 27.0

3

17a -- -- -- -- -- --

19 3.12 41.5 8.81 7.99 10.0 27.2

20 3.14 42.0 8.89 8.11 9.10 27.3

21 3.17 42 8.63 8.2 12.8 27.9

22 3.34 43.8 8.04 8.11 10.7 30.6

23 7.68 91.7 6.39 5.91 5.76 6.68

24 3.65 47.2 8.11 7.84 12.3 26.6

1

A tracer-calculated streamflow could not be determined at this site because the dye was not fully mixed in Tenmile Creek. A streamflow 

value equal to the value at site 2 was used.

2

The dye concentration at this site was anomalous; therefore, an estimated streamflow value equal to site 7 plus one-half of the difference 

from sites 7 to 11 was assigned to this site.

3

Streamflow (0.23 L/s) at this site, a fork of Spring Creek, was added to site 17 to calculate loads for Spring Creek.
16 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Table 4. Results of streamflow calculated by tracer injection, surface-water inflow, subsurface inflow, and 

associated water-quality analyses of samples collected from upper Tenmile Creek drainage basin, Montana, 

September 2011.—Continued

[Subsurface inflows were assigned point of inflow but occurred between upstream and downstream points within the reach. Sites were 

assigned short numbers (Site number), defined in table 1, and displayed on figure 2. Surface-water inflow sites are bold. Abbreviations: 

ft, feet; mg/L, milligrams per liter; L/s, liters per second; μS/cm, microseimens per centimeter; CaCO3, calcium carbonate; μg/L, micrograms per liter; ab, above; nr, near; --, no data; bl, below; E, estimated; LB, left bank (looking downstream); RB, right bank (looking 

downstream); <, less than]

Site

Lead, 

dissolved 

(μg/L)

Lead, 

total 

recoverable 

(μg/L)

Zinc, 

dissolved 

(μg/L)

Zinc, 

total 

recoverable 

(μg/L)

Arsenic, 

dissolved 

(μg/L)

Arsenic, 

total 

recoverable 

(μg/L)

0 -- -- -- -- -- --

1

1 0.78 1.72 331 298 8.40 10.1

2 0.80 1.73 302 289 8.59 10.3

3 0.35 0.76 185 164 10.4 10.7

4 0.77 1.77 318 285 8.69 10.4

5 0.76 1.76 317 280 8.70 10.3

5.5 0.75 1.69 314 289 8.81 10.3

6 0.04 43.9 95.7 134 28.0 25.1

6.5 1.10 2.16 314 289 9.43 10.5

6.75 22.1 26.6 62,200 57,100 544 646

7 1.13 2.74 559 514 7.19 11.5

2

8 -- -- -- -- -- --

8.5 0.16 0.23 162 145 17.7 17.9

2

9 1.1 3.04 600 538 6.94 13.0

10 0.25 0.52 185 168 20.7 21.4

11 1.21 3.24 620 569 7.02 12.2

12 1.35 3.22 670 547 7.39 12.0

13 1.30 3.58 573 559 7.27 13.3

14 1.11 3.53 580 527 7.03 13.5

15 20.9 46.9 41,500 41,800 2,980 8,430

16 0.92 4.07 1,110 1,090 33.3 115

17 0.09 0.36 72.5 71.5 8.99 9.29

18 0.15 3.87 1,050 1,040 57.6 108

3

17a -- -- -- -- -- --

19 0.69 3.81 1,090 1,040 33.9 112

20 0.54 3.90 1,070 1,070 27.9 112

21 0.99 3.61 1,100 1,080 43.0 111

22 0.74 4.23 1,200 1,150 32.4 137

23 0.15 1.18 1,040 969 61.2 59.6

24 1.07 3.56 1,220 1,170 45.7 110

1

A tracer-calculated streamflow could not be determined at this site because the dye was not fully mixed in Tenmile Creek. A streamflow 

value equal to the value at site 2 was used.

2

The dye concentration at this site was anomalous; therefore, an estimated streamflow value equal to site 7 plus one-half of the difference from sites 7 to 11 was assigned to this site.

3

Streamflow (0.23 L/s) at this site, a fork of Spring Creek, was added to site 17 to calculate loads for Spring Creek.
Quantification of Trace-Element Loading 17

The current-meter measurement conducted upstream 

from the city diversion (surface-water site 0) yielded a result 

of 83.5 L/s or about 30 percent more than the streamflow 

at surface-water site 1 (57.8 L/s) just downstream from the 

diversion, indicating that about 26 L/s of the streamflow in 

upper Tenmile Creek was being diverted to the treatment plant 

during the study.

Comparison of streamflow calculated by tracer injection determined in this study (fig. 5) and those observed in 

the 1998 trace-element loading study (Cleasby and Nimick, 

2002) indicated that streamflow values were about an order 

of magnitude less in 1998. In the 1998 study, streamflow in 

upper Tenmile Creek upstream from the city diversion was 

185 L/s, but about 5 L/s was measured in upper Tenmile Creek 

downstream from the city diversion. This small amount of 

streamflow in 1998 was evident throughout the study reach 

with minimal gains downstream to site 24.

2011 streamflow entering 

study reach upstream

1998 streamflow 

2011 streamflow

1998 surface-water inflow

2011 surface-water inflow

EXPLANATION

Site number (table 1; fig. 2)

5.5

13

18

0 6,000

1

9

11

12

14

16

19

20

21

22

24

4

6

8

10

60

50

70

80

90

100

1,000 2,000 3,000 4,000 5,000

Streamflow, in liters per second

0

2

2

4

5

6.5

7

Distance downstream from injection site, in feet

Figure 5. Streamflow calculated by tracer injection, upper Tenmile Creek drainage basin, Montana, 1998 and 2011.
18 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Water Quality

Results of water-quality sampling in this study indicated 

that overall trace-element concentrations measured in 2011 

were lower than those measured in 1998, but concentrations of 

trace elements originating from mine adits did not change substantially. The observed decreases in trace-element concentrations since 1998 were likely caused by dilution from increased 

streamflow rather than from reduced trace-element concentrations introduced from mining.

Synoptic water-quality samples were collected at the 

19 main-stem sites in upper Tenmile Creek and the 8 surfacewater inflow sites and were analyzed for physical properties, 

hardness (calcium and magnesium), and selected dissolved 

and total-recoverable trace-element concentrations. The 

groundwater samples were analyzed for the same suite of constituents as surface-water samples except for total-recoverable 

trace elements. It was assumed that dissolved concentrations 

would be about the same as total-recoverable concentrations 

because groundwater samples should not contain sediment. 

Results are listed in table 4 and table 5, and selected constituents are graphically displayed in figures 6 and 7. Water-quality 

data collected for the 2011 study also are available in the 

USGS National Water Information System (NWIS) database 

(U.S. Geological Survey, 2018). Results of the 1998 tracer 

study and applicable Montana water-quality standards for cadmium, copper, lead, zinc, and arsenic (Montana Department of 

Environmental Quality, 2017) also are shown in figure 7.

Two criteria levels for selected trace-element concentrations, chronic and acute, are established for freshwater 

habitats. Chronic criteria are established for the protection 

against long-term exposure to moderately elevated concentrations. If concentrations exceed the chronic criteria for long 

periods, detrimental effects on growth and reproduction might 

be seen in aquatic populations. Acute criteria are established 

for protection against short-term exposure to highly elevated 

concentrations that can be lethal to aquatic organisms. Because 

tolerance to trace-element exposure can vary among species, 

or between individuals within the same species, aquatic-life 

criteria are only general guidelines. The Montana criteria for 

trace-element toxicity are based on total-recoverable concentrations, but dissolved and total-recoverable trace-element 

concentrations are compared to the criteria in this report. 

Aquatic-life criteria for cadmium, copper, lead, and zinc vary 

with water hardness (Montana Department of Environmental 

Quality, 2017), with trace-element toxicity decreasing with 

increasing hardness. The aquatic-life criteria shown in figure 7 

were calculated using a hardness of 35 milligrams per liter 

measured as calcium carbonate, the mean hardness measured 

at the main stem sites during the tracer injection. Overall, the 

State of Montana human-health criteria for total-recoverable 

cadmium and arsenic were exceeded in parts of upper Tenmile 

Creek.

Surface Water

The pH in upper Tenmile Creek remained relatively constant (ranging from 6.4 to 7.2) during the 2011 study compared 

to the pH during 1998, which ranged from 5.0 to 7.4 (fig. 6). 

During both studies, the pH was near neutral in the upper portion of the study reach from surface-water sites 1 through 10. 

In 1998, the main-stem pH declined to less than 5.5 downstream from surface-water site 11 (2,120 ft) and remained 

below 6.0 for an almost 1,300-ft reach of upper Tenmile Creek 

between surface-water sites 11 (2,120 ft) and 18 (3,415 ft). 

The area around Lee Mountain Mine and the Susie Lode adit 

contributed acidic water that depressed pH in this stream 

reach during the 1998 study. The Lee Mountain Mine adit was 

a diffuse source to upper Tenmile Creek in 1998. Discharge 

from this area was not channelized, and water percolated into 

the unconsolidated mine waste, seeping into upper Tenmile 

Creek over a broader reach. The small volume of streamflow 

in upper Tenmile Creek in 1998 resulted in little neutralization 

of the acidic inflows from these sources. Although pH values 

in the two acidic inflows were similar during both studies, 

they did not have a substantial effect on upper Tenmile Creek 

during 2011 because of the larger volume of streamflow. The 

pH increased downstream from Spring Creek during the 1998 

study such that pH values at the most downstream site in 1998 

and 2011 were roughly equivalent. The highest pH during 

both studies was measured at the surface-water inflow site 6 

(1,245 ft). At site 6, the pH was over 8.0 during both studies. 

This inflow was a pipe with a small discharge.

The 2011 concentration profiles for cadmium, copper, and 

zinc through the study reach displayed similar patterns (fig. 7). 

Main-stem concentrations for these trace elements increased 

substantially in response to contributions from the Lee Mountain Mine adit (site 6.75) and the Susie Lode adit (site 15). 

Other than the two concentration increases attributed to 

discharge contributions from these adits, main-stem concentrations remained relatively unchanged. Dissolved concentrations 

increased about 6.5, 5, and 3 times over the entire study reach 

for cadmium, copper, and zinc, respectively. For these trace 

elements, main-stem dissolved and total-recoverable concentrations were roughly equivalent, indicating that they existed 

mostly in the dissolved form. The exception to this was that 

downstream from the Susie Lode adit discharge (surface-water 

inflow site 15), the increase in main-stem concentrations of 

total-recoverable copper (from 7.74 to 28.1 μg/L) was higher 

than it was for the dissolved concentrations (from 5.22 μg/L to 

13.3 μg/L; table 4).
Table 5. Groundwater levels and results of water-quality analyses of groundwater samples collected at wells adjacent to upper Tenmile Creek, Mon[USGS, U.S. Geological Survey; hh, hour; mm, minute; ft, foot; --, not determined; μS/cm, microsiemen per centimeter; mg/L, milligram per liter; μg/L, microgram per liter]

Site

number

table 2;

fig. 3)1

USGS station 

identification

number

Sample 

date

Sample 

time

(hhmm)

Land

surface 

elevation 

(ft)

Water level 

(ft)

 Groundwater 

level 

elevation 

(ft)

Surface water 

elevation

(ft)

Right bank wells1

LMRB–1 462907112144601 9/13/2011 0900 5,265 2.20 5,262.80 5,263.55 

LMRB-2 462911112144501 9/13/2011 1100 5,244 1.12 5,242.85 5,242.94 

Left bank wells1

LMLB–1 462908112144601 9/13/2011 1000 5,270 6.89 5,262.83 5,263.61 

LMLB–2 462909112144701 9/13/2011 1200 5,261 3.56 5,257.24 -- 

LMLB–3 462910112144601 9/13/2011 1400 5,259 8.04 5,251.28 -- 

LMLB–4 462913112144801 9/13/2011 1500 5,242 0.65 5,241.01 -- 

LMLB–5 462913112144701 9/13/2011 1400 5,238 0.51 5,237.46 5,237.65 

LMLB–6 462914112144701 9/13/2011 1500 5,237 0.90 5,236.03 5,235.67 

Site

number

table 2;

fig. 3)1

pH

(standard units)

Specific

conductance

(μS/cm)

Calcium,

 water, 

dissolved 

(mg/L)

 Magnesium, 

water, 

dissolved 

(mg/L)

Cadmium, 

water, 

dissolved 

(μg/L)

Copper, 

water, 

dissolved 

(μg/L)

Lead, 

water, 

dissolved 

(μg/L)

 

Right bank wells1

LMRB–1 7.3 96 9.59 2.29 1.04 2.1 0.203 

LMRB–2 6.2 107 9.66 2.54 2.48 0.55 0.218 

Left bank wells1

LMLB–1 6.9 366 40.3 13.1 1.75 1.41 0.116 

LMLB–2 4.4 161 11.0 3.27 29.4 69.9 13.3 

LMLB–3 3.2 608 23.0 5.56 91.6 296 534 

LMLB–4 3.5 2,110 180 51.0 7,900 46,200 18.7 1,

LMLB–5 7.0 322 31.8 9.21 0.751 0.54 3.4 

LMLB–6 7.1 390 40.8 11.8 0.345 0.51 0.817 

1Left bank and right bank are relative to Tenmile Creek facing downstream.2Positive value indicates groundwater level higher than stream level and negative value (‒) indicates groundwater level lower than stream level.
20 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Rol19-0021_fig06

1 6.75 10 15 17 23

Surface-water inflow site 

Tenmile Creek main-stem sites 

EXPLANATION

6,000

Site number (table 1; fig. 2)

pH, in standard units

2011

1998

2011

1998

2

3

4

5

6

7

8

9

10

0 1,000 2,000 3,000 4,000 5,000

Distance downstream from injection point, in feet

3

Figure 6. Values of pH measured in main-stem and inflow sites downstream from the tracer-injection point, upper Tenmile 

Creek drainage basin, Montana, 1998 and 2011.

Comparison between results of the 1998 and 2011 studies 

indicated that increases in main-stem trace-element concentrations after flowing through the Lee Mountain Mine area 

(downstream from inflow site 6.75) were substantially greater 

in 1998 than in 2011 (fig. 7). Concentrations of cadmium and 

zinc were approximately equal in both studies in the upper 

portion of the study reach from surface-water sites 1 to 5 

upstream from the Lee Mountain Mine adit. However, mainstem copper concentrations in this area were about twice as 

high in 1998 as in 2011. In 1998, main-stem concentrations of 

cadmium, copper, and zinc steadily increased over an approximately 1,000-ft reach in the Lee Mountain Mine area from 

surface-water sites 5 to 11. In contrast, the 2011 increases in 

main-stem concentrations for theses trace elements occurred 

more as a point source from the channelized Lee Mountain 

Mine adit discharge at site 6.75 (table 4). In 1998, mainstem cadmium concentrations increased by about 17 times 

through this reach, copper increased by about 7 times, and 

zinc increased by about 11 times (Cleasby and Nimick, 2002). 

In 2011, concentrations of cadmium, copper, and zinc in this 

area increased by less than three times. At the time of the 1998 

study, there was no surface-water inflow observed in the mine 

area, and the increases in trace-element concentrations were 

attributed to subsurface inflow.

Concentration profiles for lead were different than those 

for cadmium, copper, or zinc (fig. 7). In 2011, dissolved 

lead concentrations were relatively constant downstream 

from the Lee Mountain Mine adit (site 6.75). Downstream 

from the Susie Lode adit (site 15), concentrations decreased, 

and total-recoverable lead concentrations steadily increased 

from surface-water site 5 to the end of the study reach. This 

indicates that main-stem conditions may have favored the 

precipitation of lead downstream from site 5 to the end of the 

study reach. This partitioning from dissolved lead to particulate lead was expected because, at near-neutral pH, dissolved 

lead forms colloids and is converted to the particulate fraction 

(Hem, 1985).

Similar to the other measured trace elements, lead concentrations in upper Tenmile Creek substantially increased 

as it flowed through the Lee Mountain Mine area in 1998 

(surface-water sites 5–11; fig. 7). This increase was not as large 

in 2011, although concentrations in the Lee Mountain Mine 

adit discharge (site 6.75) exceeded 20 μg/L for both dissolved 

and total-recoverable lead (table 4). The difference in upper 

Tenmile Creek lead concentrations between 1998 and 2011 was 

due to the difference in pH associated with smaller streamflow volumes in 1998. In 1998, downstream from the Susie 

Lode adit (site 15), where the main-stem pH increased (fig. 6), 
Quantification of Trace-Element Loading 21

Rol19-0021_fig07a

Human-health standard

Acute aquatic-life criterion

Chronic aquatic-life criterion

1998

2011

Tenmile Creek 

main-stem sites

Surface-water 

inflow site

1998

2011

Water-quality standard (from Montana 

Department of Environmental Quality, 2017)

Trace-element concentration, in micrograms per liter

A. Dissolved cadmium B. Total-recoverable 

cadmium

D. Total-recoverable 

copper

F. Total-recoverable 

lead

E. Dissolved lead

C. Dissolved copper

Site number (table 1; fig. 2)

0 1,000 2,000 3,000 4,000 5,000 6,000 0 1,000 2,000 3,000 4,000 5,000 6,000

EXPLANATION

3 

6 

6.75 

10 

15

17

23

Distance downstream from injection point, in feet

0.1

1

10

100

1,000

1

10

100

1,000

10,000

1

0.1

10

100

3 

6 

6.75 

10 

15

17

23

Figure 7a. Concentrations of A. dissolved cadmium, B. total-recoverable cadmium, C. dissolved copper, D. total-recoverable copper, 

E. dissolved lead, F. total-recoverable lead, G. dissolved zinc, H. total-recoverable zinc, I. dissolved arsenic, and J. total-recoverable

arsenic measured in main-stem and inflow sites downstream from the tracer-injection point, upper Tenmile Creek drainage basin,

Montana, 1998 and 2011.
22 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

10

100

1,000

10,000

100,000

0 1,000 2,000 3,000 4,000 5,000

1

10

100

1,000

10,000

0 1,000 2,000 3,000 4,000 5,000

Distance downstream from injection point, in feet

6,000 6,000

Trace-element concentration, in micrograms per liter

Human-health standard

Acute aquatic-life criterion

Chronic aquatic-life criterion

1998

2011

Tenmile Creek 

main-stem sites

Surface-water 

inflow site

1998

2011

Water-quality standard (from Montana 

Department of Environmental Quality, 2017)

G. Dissolved zinc

I. Dissolved arsenic

H. Total-recoverable

zinc

J. Total-recoverable

arsenic

3 

6 

6.75 

10 

15

17

23

3 

6 

6.75 

10 

15

17

23

Site number (table 1; fig. 2)

EXPLANATION

Figure 7b. Concentrations of A. dissolved cadmium, B. total-recoverable cadmium, C. dissolved copper, D. total-recoverable copper, 

E. dissolved lead, F. total-recoverable lead, G. dissolved zinc, H. total-recoverable zinc, I. dissolved arsenic, and J. total-recoverable

arsenic measured in main-stem and inflow sites downstream from the tracer-injection point, upper Tenmile Creek drainage basin,

Montana, 1998 and 2011.
Quantification of Trace-Element Loading 23

dissolved lead concentrations decreased, and at the end of the 

study reach (site 24), dissolved lead concentrations were like 

those measured in 2011. Concentrations of total-recoverable 

lead at site 24 were about 4 times higher in 1998 than in 2011.

Dissolved and total-recoverable arsenic concentrations in 

2011 were relatively low, except for one concentration peak 

from the Susie Lode adit discharge at site 15 (fig. 7). This 

source contributed most of the main-stem arsenic concentration, which increased by 5 times in the dissolved fraction and 

by 10 times in the total-recoverable arsenic fraction throughout the study reach. Downstream from this large increase, the 

concentrations of both dissolved and total-recoverable arsenic 

remained relatively constant.

Total-recoverable arsenic concentrations were similar 

between 1998 and 2011, but dissolved arsenic concentrations were much more variable between these years. In 1998, 

dissolved arsenic concentrations in upper Tenmile Creek 

decreased sharply as it flowed through the Lee Mountain Mine 

area (site 6.75), but not in 2011. This is the same stream reach 

where concentrations of cadmium, copper, and zinc increased 

in both years. This decrease in dissolved arsenic concentrations in 1998 was likely caused by adsorption and (or) 

coprecipitation of dissolved arsenic with visible iron particulates in the main stem of upper Tenmile Creek (Cleasby and 

Nimick, 2002). As previously mentioned, there was no surface 

inflow to upper Tenmile Creek in this reach during the 1998 

study and arsenic, therefore, entered upper Tenmile Creek 

through diffuse subsurface inflow. The reclamation work done 

in this area after 1998 included re-contouring the mine area 

to concentrate and confine the diffuse subsurface flow into 

one conduit flowing into a lime treatment pond. Although the 

lime pond was not being maintained during the 2011 study, 

some iron particulates likely precipitated through oxidation, 

depending on the redox conditions, as the water was exposed 

to air converting ferrous iron into ferric iron as the water 

entered upper Tenmile Creek. Therefore, dissolved arsenic 

concentrations in 2011 may have been higher than in 1998 in 

the absence of iron colloids formed in the lime treatment pond 

flowing into upper Tenmile Creek from the Lee Mountain 

Mine area.

Trace-element concentrations in upper Tenmile Creek 

were lower, overall, in 2011 than in 1998. Dissolved and totalrecoverable cadmium concentrations downstream from the 

Susie Lode adit (site 15) exceeded the human-health standard 

of 5 μg/L in 2011. The human-health standard of 10 μg/L for 

total-recoverable arsenic was exceeded at main-stem sites 

throughout the entire 5,020-ft study reach. Total-recoverable 

zinc concentrations in 2011 approached the human-health 

standard of 2,000 μg/L in the stream reach downstream from 

the Susie Lode adit but did not exceed it.

Exceedances of the calculated acute aquatic-life criteria 

were observed at several main-stem sites for total-recoverable 

lead (17.6 μg/L) in 1998, at several sites for total-recoverable 

copper (4.5 μg/L) in 2011, and at all sites for cadmium 

(0.63 μg/L) and zinc (43.2 μg/L) in both 1998 and 2011. In 

2011, total-recoverable copper concentrations exceeded the 

acute aquatic-life criterion from site 7, just downstream from 

the Lee Mountain Mine adit discharge, to the end of the study 

reach, whereas, in 1998, the total-recoverable copper criterion 

was exceeded throughout the study reach. Main-stem dissolved and total-recoverable lead concentrations exceeded the 

chronic aquatic-life criterion throughout the study reach in 

2011 except for site 20, where dissolved lead concentrations 

were lower than the criterion. In 1998, lead concentrations at 

all main-stem sites exceeded the chronic aquatic-life criterion 

(0.69 μg/L), and several sites exceeded the acute aquatic-life 

lead criterion, but concentrations were generally lower in 2011 

than in 1998.

Groundwater

In 1998, a sample collected from along the left bank of 

upper Tenmile Creek in the Lee Mountain Mine area (site 8) 

contained the highest constituent concentrations of nearly all 

the samples collected that year (Cleasby and Nimick, 2002). 

Following that 1998 study, this area underwent substantial 

reclamation. In 2011, groundwater-levels were measured and 

water-quality samples were collected and analyzed for physical properties and dissolved trace-element concentrations from 

eight shallow wells in the Lee Mountain Mine area (table 5) 

to evaluate differences in diffuse trace-element loading from 

groundwater to upper Tenmile Creek between 1998 and 2011. 

Groundwater level and water-quality data collected during this 

study also are available in the NWIS database (U.S. Geological Survey, 2018).

Water levels were used to determine the general groundwater-flow gradient and to determine the interactions between 

the groundwater and surface water in the Lee Mountain Mine 

area. Upper Tenmile Creek is a moderately steep gradient 

stream as it flows through the Lee Mountain Mine area, dropping about 28 ft as it flows along the 985-ft reach from well 

LMLB–1 to LMLB–6 (fig. 3). Similarly, groundwater flows 

from areas of higher water-level elevation to areas of lower 

water-level elevation. Closely following the stream gradient, 

groundwater elevations declined in the downstream direction about 27 ft between the near-stream wells LMLB–1 and 

LMLB–6 (fig. 3; table 5), indicating down-valley groundwater flow as seen in many valley systems (Briar and Madison, 

1992).

The degree of interaction between the groundwater and 

upper Tenmile Creek is dependent on the groundwater level 

and stream level, as well as the hydraulic conductivity of the 

streambed material and the adjacent alluvium. Groundwater 

levels on September 13, 2011, indicated that 4 of 5 nearstream wells had groundwater elevations that were 0.08 to 

0.78 ft lower than the adjacent level in upper Tenmile Creek 

(table 5). These gradients indicated losing streamflow conditions (waterflow from upper Tenmile Creek to the groundwater) through that stream reach (between 1,115 ft and 2,000 ft 

downstream from the injection point). The most downstream 

well adjacent to the river (well LMLB–6; table 5) had a higher 
24 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

groundwater elevation relative to the surface water elevation in 

upper Tenmile Creek, indicating gaining streamflow conditions 

(waterflow from the groundwater to upper Tenmile Creek).

Trace-element concentrations in groundwater samples 

ranged from being like concentrations in upper Tenmile 

Creek to being extremely elevated (table 5). Concentrations in groundwater from the right-bank wells (LMRB–1 

and LMRB–2) were generally lower than in those from the 

left-bank wells. Trace-element concentrations measured in 

LMRB–1 samples were like concentrations found in upper 

Tenmile Creek (surface-water site 5 is closest to LMRB–1; 

figs. 2–3; tables 4–5), and concentrations of cadmium and 

zinc in LMRB–2 samples were greater than concentrations 

in upper Tenmile Creek. The wells sampled on the left-bank 

side of upper Tenmile Creek had variable trace-element 

concentrations, and many concentrations were higher than 

concentrations measured in upper Tenmile Creek. The three 

wells that were in place before the study (LMLB–2, 3, and 4) 

were installed into the re-contoured fill material 50 to 135 ft 

away from the upper Tenmile Creek bank. The pH in water 

from these wells were all acidic (3.2–4.4), and trace-element 

concentrations in samples were generally elevated compared 

to the wells sampled immediately adjacent to the streambed, 

perhaps because the near-stream well concentrations were 

affected by flows from the stream to the adjacent groundwater. 

Concentrations of dissolved cadmium (7,900 μg/L), copper 

(46,200 μg/L), and zinc (1,040,000 μg/L) in LMLB–4 samples 

were, by far, the highest observed during this study.

Surface-water elevations in upper Tenmile Creek were 

higher than the groundwater elevations measured in nearby 

wells on both the left and right banks near the Lee Mountain 

Mine, indicating that upper Tenmile Creek may have been 

losing surface flow to the groundwater in this area. Under losing conditions, streamflows and trace-element concentrations 

from upper Tenmile Creek may have affected trace-element 

concentrations in the groundwater wells. Measured traceelement concentrations in the groundwater wells were greater 

than in upper Tenmile Creek, but groundwater concentrations could have been much greater if the creek was gaining 

rather than losing in this area. The down-valley gradient of the 

groundwater indicated that groundwater flows were toward 

upper Tenmile Creek farther downstream. The groundwater 

elevation of the farthest downstream well (LMLB–6) was 

greater than the adjacent surface-water elevations in upper 

Tenmile Creek, indicating that the creek was gaining in this 

area. Streamflows determined by dye tracer data indicated that 

upper Tenmile Creek gained 4.4 L/s between sites 11 and 14 

(table 4); however, trace-element concentrations for these sites 

did not substantially increase. Long-term monitoring might be 

warranted to fully understand the groundwater/surface-water 

interactions and trace-element loading from the Lee Mountain 

Mine area under various hydrologic conditions.

Quantification of Trace-Element Loading

Estimation of trace-element load is critical for determining the mass of specific trace elements delivered to upper 

Tenmile Creek and for measuring the changes in trace-element 

loads following implementation of remediation or management actions. Load is the mass of a constituent transported 

downstream during a given period and is calculated as the 

product of a constituent concentration and streamflow. For 

chemically conservative constituents, inflows contribute their 

load in a cumulative manner to the overall load in the stream. 

Loads and instream concentrations are dependent on the 

volume of water transporting the constituent of interest. For 

comparative purposes, loads are commonly expressed in terms 

of mass transported per unit time (for example, micrograms 

per second (μg/s) for instantaneous loads or kilograms per 

year for annual loads). Instantaneous loads for dissolved and 

total-recoverable cadmium, copper, lead, zinc, and arsenic 

were calculated for the 19 main-stem and 8 surface-water 

inflow sites sampled during this study (table 6).

Loading profiles illustrate the longitudinal distribution of 

load and can be used to identify locations of important sources 

and sinks that contribute to or subtract from the overall constituent load. Main-stem segments where constituent loads are 

added to or removed from the water column can be identified 

by comparing the main-stem loads and the cumulative load 

from surface-water inflows. The profile of main-stem load 

represents the measured load at each main-stem sampling site. 

This load is the net result of contributions from the sampled 

and unsampled (groundwater and seeps) surface inflows, 

load loss from particulate deposition, and streamflow loss to 

groundwater. The main-stem load profile reflects the actual 

instream load and the net effect of all inputs and losses. The 

partitioning of elements between the dissolved and particulate 

fractions can be assessed by comparing the dissolved and 

total-recoverable (dissolved plus particulate) instream loads. 

Loads containing approximately equal portions of dissolved 

and total-recoverable fractions are considered mostly dissolved. Subtracting the dissolved load from the total-recoverable load provides an estimate of the instream particulate load, 

which is assumed to be primarily colloidal.

The cumulative surface-water inflow profile illustrates 

the sum of the load accrued from all the sampled surface-water 

inflows up to that location on the main stem. The cumulative 

surface-water inflow profile only represents the measured 

surface-water inflows and does not account for subsurface 

inflows. Loads from subsurface inflows can be calculated as 

the difference between the main-stem load and the cumulative 

surface-water inflow load. Less main-stem load than cumulative surface-water inflow load indicates load loss by geochemical precipitation, streambed deposition, or streamflow loss to 

groundwater.
Quantification of Trace-Element Loading 25

Table 6. Instantaneous loads of trace elements measured in surface-water samples, upper Tenmile Creek drainage basin, Montana, 

September 2011.

[Surface-water inflow sites are bold. μg/s, microgram per second; ab, above; bl, below; ft, foot; LB, left bank (looking downstream); <, less than calculated 

load; RB, right bank (looking downstream)]

Site 

number

(table 1; 

fig. 2)

Station description

Cadmium 

load, 

dissolved 

(μg/s)

Cadmium load, 

total 

recoverable 

(μg/s)

Copper load, 

dissolved 

(μg/s)

Copper load, 

total 

recoverable 

(μg/s)

0 Tenmile Creek ab City Diversion at Rimini1 102 102 225 264

1 Tenmile Creek bl City Diversion at Rimini (injection point) 70.5 70.5 152 179

2 Tenmile Creek 365 ft bl City Diversion at Rimini 70.6 69.4 157 179

3 Tenmile LB seep 665 ft bl City Diversion at Rimini 0.03 0.03 0.14 0.16

4 Tenmile Creek 695 ft bl City Diversion at Rimini 69.9 68.8 152 184

5 Tenmile Creek 1,115 ft bl City Diversion at Rimini 71.3 68.9 158 178

5.5 Tenmile Creek 1,215 ft bl City Diversion at Rimini 70.7 68.9 151 175

6 Tenmile RB discharge pipe 1,245 ft bl City Diversion 0.08 0.11 <0.06 18.3

6.5 Tenmile Creek 1,350 ft bl City Diversion at Rimini 83.1 76.6 177 195

6.75 Lee Mountain Mine adit discharge at Rimini 128 123 89.9 123

7 Tenmile Creek 1,780 ft bl City Diversion at Rimini 203 187 317 402

8.5 Tenmile Creek RB seep 1,970 bl City Diversion at Rimini 0.10 0.09 0.54 0.73

9 Tenmile Creek 1,985 ft bl City Diversion at Rimini 202 188 322 431

10 Beaver Creek at mouth at Rimini 0.02 0.02 0.20 0.26

11 Tenmile Creek 2,120 ft bl City Diversion at Rimini 233 211 410 527

12 Tenmile Creek 2,420 ft bl City Diversion at Rimini 252 210 429 566

13 Tenmile Creek ab Susie Lode Adit at Rimini 233 217 444 615

14 Tenmile Creek 3,015 ft bl City Diversion at Rimini 240 223 410 608

15 Susie Lode Adit discharge at mouth at Rimini 459 431 1,380 1,350

16 Tenmile Creek 3,250 ft bl City Diversion at Rimini 714 698 1,090 2,300

17 Spring Creek at Mouth at Rimini

2 2.98 3.04 22.8 29.1

18 Tenmile Creek 3,415 ft bl City Diversion at Rimini 569 677 446 2,270

19 Tenmile Creek 3,575 ft bl City Diversion at Rimini 746 677 847 2,300

20 Tenmile Creek bl Spring Creek at Rimini 805 734 824 2,470

21 Tenmile Creek 4,180 ft bl City Diversion at Rimini 781 742 1,158 2,520

22 Tenmile Creek 4,675 ft bl City Diversion at Rimini 739 745 983 2,810

23 Moore's Spring Creek at mouth at Rimini 4.52 4.18 4.08 4.73

24 Tenmile Creek 5,020 ft bl City Diversion at Rimini 782 756 1,190 2,560

1

Load values at site 0 were calculated using streamflow values that were measured using current meter methods and concentration data from site 1.

2

Two forks of Spring Creek were entering Tenmile Creek (sites 17 and 17a; table 1). Only site 17 was sampled, and loads were computed by using the 

combined streamflow of both forks.
26 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Table 6. Instantaneous loads of trace elements measured in surface-water samples, upper Tenmile Creek drainage basin, Montana, 

September 2011.—Continued

[Surface-water inflow sites are bold. μg/s, microgram per second; ab, above; bl, below; ft, foot; LB, left bank (looking downstream); <, less than calculated 

load; RB, right bank (looking downstream)]

Site 

number

(table 1; 

fig. 2)

Station description

Lead load, 

dissolved 

(μg/s)

Lead load, 

total 

recoverable 

(μg/s)

Zinc load, 

dissolved 

(μg/s)

Zinc load, 

total 

recoverable 

(μg/s)

0 Tenmile Creek ab City Diversion at Rimini1 66.6 147 28,300 25,500

1 Tenmile Creek bl City Diversion at Rimini (injection point) 45.0 99.4 19,100 17,200

2 Tenmile Creek 365 ft bl City Diversion at Rimini 46.4 100 17,500 16,700

3 Tenmile LB seep 665 ft bl City Diversion at Rimini 0.02 0.04 10.5 9.29

4 Tenmile Creek 695 ft bl City Diversion at Rimini 45.9 105 18,800 16,900

5 Tenmile Creek 1,115 ft bl City Diversion at Rimini 45.4 105 18,900 16,800

5.5 Tenmile Creek 1,215 ft bl City Diversion at Rimini 44.8 101 18,800 17,300

6 Tenmile RB discharge pipe 1,245 ft bl City Diversion 0.00 2.49 5.42 7.59

6.5 Tenmile Creek 1,350 ft bl City Diversion at Rimini 79.5 156 22,700 20,900

6.75 Lee Mountain Mine adit discharge at Rimini 9.06 10.9 25,500 23,400

7 Tenmile Creek 1,780 ft bl City Diversion at Rimini 82.7 201 40,900 37,600

8.5 Tenmile Creek RB seep 1,970 bl City Diversion at Rimini 0.01 0.02 13.8 12.3

9 Tenmile Creek 1,985 ft bl City Diversion at Rimini 81.0 224 44,200 39,600

10 Beaver Creek at mouth at Rimini 0.01 0.01 5.24 4.76

11 Tenmile Creek 2,120 ft bl City Diversion at Rimini 89.7 240 45,900 42,200

12 Tenmile Creek 2,420 ft bl City Diversion at Rimini 101 240 50,000 40,800

13 Tenmile Creek ab Susie Lode Adit at Rimini 101 279 44,700 43,600

14 Tenmile Creek 3,015 ft bl City Diversion at Rimini 87.1 277 45,500 41,400

15 Susie Lode Adit discharge at mouth at Rimini 18.9 42.5 37,600 37,900

16 Tenmile Creek 3,250 ft bl City Diversion at Rimini 75.1 333 90,800 89,100

17 Spring Creek at Mouth at Rimini

2 0.32 1.27 253 250

18 Tenmile Creek 3,415 ft bl City Diversion at Rimini 12.5 325 88,300 87,400

19 Tenmile Creek 3,575 ft bl City Diversion at Rimini 58.3 323 92,300 88,100

20 Tenmile Creek bl Spring Creek at Rimini 49.1 353 96,800 96,800

21 Tenmile Creek 4,180 ft bl City Diversion at Rimini 89.1 327 99,500 97,700

22 Tenmile Creek 4,675 ft bl City Diversion at Rimini 67.7 389 110,000 106,000

23 Moore's Spring Creek at mouth at Rimini 0.11 0.84 736 686

24 Tenmile Creek 5,020 ft bl City Diversion at Rimini 103 343 118,000 113,000

1

Load values at site 0 were calculated using streamflow values that were measured using current meter methods and concentration data from site 1.

2

Two forks of Spring Creek were entering Tenmile Creek (sites 17 and 17a; table 1). Only site 17 was sampled, and loads were computed by using the 

combined streamflow of both forks.
Quantification of Trace-Element Loading 27

Table 6. Instantaneous loads of trace elements measured in surface-water samples, upper Tenmile Creek drainage basin, Montana, 

September 2011.—Continued

[Surface-water inflow sites are bold. μg/s, microgram per second; ab, above; bl, below; ft, foot; LB, left bank (looking downstream); <, less than calculated 

load; RB, right bank (looking downstream)]

Site 

number

(table 1; 

fig. 2)

Station description

Arsenic load, 

dissolved 

(μg/s)

Arsenic load, 

total 

recoverable 

(μg/s)

0 Tenmile Creek ab City Diversion at Rimini1 719 864

1 Tenmile Creek bl City Diversion at Rimini (injection point) 486 584

2 Tenmile Creek 365 ft bl City Diversion at Rimini 497 596

3 Tenmile LB seep 665 ft bl City Diversion at Rimini 0.59 0.61

4 Tenmile Creek 695 ft bl City Diversion at Rimini 515 616

5 Tenmile Creek 1,115 ft bl City Diversion at Rimini 521 617

5.5 Tenmile Creek 1,215 ft bl City Diversion at Rimini 528 617

6 Tenmile RB discharge pipe 1,245 ft bl City Diversion 1.59 1.42

6.5 Tenmile Creek 1,350 ft bl City Diversion at Rimini 682 759

6.75 Lee Mountain Mine adit discharge at Rimini 223 264

7 Tenmile Creek 1,780 ft bl City Diversion at Rimini 526 842

8.5 Tenmile Creek RB seep 1,970 bl City Diversion at Rimini 1.50 1.52

9 Tenmile Creek 1,985 ft bl City Diversion at Rimini 511 957

10 Beaver Creek at mouth at Rimini 0.59 0.61

11 Tenmile Creek 2,120 ft bl City Diversion at Rimini 520 904

12 Tenmile Creek 2,420 ft bl City Diversion at Rimini 551 895

13 Tenmile Creek ab Susie Lode Adit at Rimini 567 1,040

14 Tenmile Creek 3,015 ft bl City Diversion at Rimini 552 1,060

15 Susie Lode Adit discharge at mouth at Rimini 2,700 7,640

16 Tenmile Creek 3,250 ft bl City Diversion at Rimini 2,730 9,400

17 Spring Creek at Mouth at Rimini

2 31.4 32.4

18 Tenmile Creek 3,415 ft bl City Diversion at Rimini 4,840 9,080

19 Tenmile Creek 3,575 ft bl City Diversion at Rimini 2,870 9,480

20 Tenmile Creek bl Spring Creek at Rimini 2,520 10,100

21 Tenmile Creek 4,180 ft bl City Diversion at Rimini 3,890 10,000

22 Tenmile Creek 4,675 ft bl City Diversion at Rimini 2,980 12,600

23 Moore's Spring Creek at mouth at Rimini 43.3 42.20

24 Tenmile Creek 5,020 ft bl City Diversion at Rimini 4,400 10,600

1

Load values at site 0 were calculated using streamflow values that were measured using current meter methods and concentration data from site 1.

2

Two forks of Spring Creek were entering Tenmile Creek (sites 17 and 17a; table 1). Only site 17 was sampled, and loads were computed by using the 

combined streamflow of both forks.
28 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

The main-stem total-recoverable cadmium load in 2011 

(fig. 8) increased from 70.5 μg/s at the injection point to 

756 μg/s at the bottom of the study reach (table 7), a nearly 

elevenfold increase along the 5,020-ft study reach. Loads of 

dissolved and total-recoverable cadmium in the main-stem 

sites were generally equivalent (table 6), indicating that the 

dissolved fraction comprised nearly all the cadmium load in 

upper Tenmile Creek. About 81 percent of the increase in dissolved cadmium load in the upper Tenmile Creek study reach 

was accounted for by the incoming load from the two adits. 

The Lee Mountain Mine adit and Susie Lode adits contributed 

about 18 percent and 69 percent, respectively, of the 685 μg/s 

of load accrued in the reach. Diffuse total-recoverable cadmium loading also occurred in the 1,770-ft reach from site 16, 

3,250 ft downstream from the injection point, to the end of the 

study reach. This reach accounted for about 8.5 percent of the 

cadmium loading within the entire study reach.

The main-stem copper load in 2011 increased almost 

eightfold, from 225 μg/s upstream from the injection point 

(site 0) to 1,190 μg/s at the end of the study reach, for dissolved copper and fourteenfold, from 264 μg/s to 2,560 μg/s, 

for total-recoverable copper (table 6; fig. 9). Unlike cadmium, 

the copper load was primarily in the dissolved form only in 

the upper portion of the study reach (from the injection point 

to 1,245 ft downstream from the injection point). Just downstream from the Lee Mountain Mine adit, about 1,400 ft downstream from the injection point, the total load was markedly 

dominated by the total-recoverable fraction. Downstream from 

the Susie Lode adit, about 3,040 ft downstream from the injection point to the end of the study reach, the total-recoverable 

load comprised more than one-half of the copper load in upper 

Tenmile Creek (fig. 9). The Susie Lode adit (near site 15) 

was the largest contributor of total-recoverable copper to the 

main stem during the study. This source accounted for most 

of the total-recoverable copper load introduced to the study 

reach. The Lee Mountain Mine adit accounted for only about 

5 percent of the increase in the total-recoverable copper load. 

Other surface-water inflows accounted for only about 2 percent of the total-recoverable copper load entering the main 

stem during this study. About one-third of the total-recoverable copper load entering upper Tenmile Creek was from diffuse sources such as groundwater or re-mobilization of copper 

from the streambed. Two stream reaches, between 2,120 ft 

and 3,015 ft and between 3,250 ft and 5,020 ft downstream 

from the injection point, accounted for most of the diffuse 

load entering upper Tenmile Creek. A total-recoverable copper 

load increase of about 81 μg/s, or about 4 percent of the total 

reach accrual, occurred near Beaver Creek, between 2,120 ft 

and 3,015 ft downstream from the injection point, but the 

contribution from the surface inflow of Beaver Creek was less 

than 1 μg/s of this increase. The 1,770-ft stream reach between 

3,250 ft downstream from the injection point to the end of the 

study reach contributed about 260 μg/s of the total-recoverable 

copper loading to upper Tenmile Creek.

Site number (table 1; fig. 2)

Cadmium load, in micrograms per second

Distance downstream from injection point, in feet

0

200

400

600

800

1,000

0 6.75 10 15 17 23

0 1,000 2,000 3,000 4,000 5,000

−50

6,000

2011 dissolved load

2011 total recoverable load

2011 cumulative 

dissolved load 

2011 cumulative 

total recoverable load 

EXPLANATION

Tenmile Creek main-stem sites 

Surface-water inflow 

Loads entering the 2011 

study reach upstream 

from site 0 (table 1)

Figure 8. Tracer-calculated cadmium loads, upper Tenmile Creek drainage basin, Montana, September 2011.
Quantification of Trace-Element Loading 29

Rol19-0021_fig09 Copper load, in micrograms per second

Distance downstream from injection point, in feet

0

500

1,000

1,500

2,000

2,500

3,000 0 6.75 10 15 17 23

0 1,000 2,000 3,000 4,000 5,000 6,000

−50

Site number (table 1; fig. 2)

2011 dissolved load

2011 total recoverable load

2011 cumulative 

dissolved load 

2011 cumulative 

total recoverable load 

EXPLANATION

Tenmile Creek main-stem sites 

Surface-water inflow 

Loads entering the 2011 

study reach upstream 

from site 0 (table 1)

Figure 9. Tracer-calculated copper loads, upper Tenmile Creek drainage basin, Montana, September 2011.

The main-stem total-recoverable lead load in 2011 (fig. 

10) increased by nearly 3.5-fold, from 99.4 μg/s to 343 μg/s,

in the 5,020-ft study reach. As predicted by the near-neutral

pH, lead in the main stem was primarily in the particulate form

(fig. 10). The main-stem total-recoverable lead load in the

upper portion of the study reach, between the injection point

to 1,215 ft downstream from the injection point, was relatively

constant. Downstream from this reach, the total-recoverable

lead load steadily increased through the end of the study reach.

The total-recoverable lead load entering upper Tenmile Creek

from surface-water inflows accounted for about 24 percent of

the total load increase (table 6; fig. 10), indicating that 76 percent of the total-recoverable lead load entered the main stem

through lead-rich bed material. This contribution from surfacewater inflows was mostly from the Lee Mountain Mine adit

(about 4.5 percent) and the Susie Lode adit (17 percent). The

right-bank discharge entering upper Tenmile Creek from a

small pipe at 1,245 ft downstream from the injection point had

very little discharge and a relatively high total-recoverable

lead concentration of 43.9 μg/L (table 4). However, the load

contribution from this source was only 2.49 μg/s (table 6), or

about 4.5 percent of the lead entering the main stem between

1,215 and 1,350 ft downstream from the injection point.

The main-stem dissolved zinc load in 2011 

(fig. 11) increased by more than sixfold over the study 

reach, from 19,100 μg/s to 118,000 μg/s. The dissolved and 

total-recoverable zinc loads in the main-stem sites were 

generally equal, indicating that the zinc load was primarily dissolved. The primary sources of zinc and their relative 

contributions to the load in upper Tenmile Creek were like 

those for cadmium, but zinc loads were more than 2 orders of 

magnitude larger than cadmium loads. About 64 percent of the 

increase in the dissolved zinc loads to upper Tenmile Creek 

was from the two adits. The Lee Mountain Mine adit contributed about 26 percent of the 5,020-ft study reach accrual, 

whereas the Susie Lode adit contributed about 38 percent. 

From 3,250 ft downstream from the injection point to the end 

of the study reach, about 27 and 25 percent, respectively, of 

the dissolved and total-recoverable zinc load was accrued. The 

load in the downstream reach could not be attributed to surface 

inflows. Rather, the load likely entered through groundwater.

The total-recoverable arsenic load in 2011 (fig. 12) 

increased by more than eighteenfold, from 584 μg/s to 

10,600 μg/s (table 7), proportionately, the largest increase 

observed. The Susie Lode adit was the primary source of arsenic, accounting for more than 76 percent of the increase in the 

total-recoverable arsenic load in the study reach. As with zinc, 

the total-recoverable arsenic load in the main-stem increased 

dramatically 3,250 ft downstream from the injection point. 

However, the dissolved load, originating almost entirely from 

the Susie Load adit, accounted for about one-half of the totalrecoverable load downstream from the adit.
30 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Rol19-0021_fig10

Site number (table 1; fig. 2)

Lead load, in micrograms per second

Distance downstream from injection point, in feet

0

200

 400

600

800 0 6.75 10 15 17 23

0 1,000 2,000 3,000 4,000 5,000 6,000

−50

2011 dissolved load

2011 total recoverable load

2011 cumulative 

dissolved load 

2011 cumulative 

total recoverable load 

EXPLANATION

Tenmile Creek main-stem sites 

Surface-water inflow 

Loads entering the 2011 

study reach upstream 

from site 0 (table 1)

Figure 10. Tracer-calculated lead loads, upper Tenmile Creek drainage basin, Montana, September 2011.

Site number (table 1; fig. 2)

Zinc load, in micrograms per second

Distance downstream from injection point, in feet

0

40,000

20,000

60,000

100,000

80,000

120,000 0 6.75 10 15 17 23

0 1,000 2,000 3,000 4,000 5,000 6,000

−50

2011 dissolved load

2011 total recoverable load

2011 cumulative 

dissolved load 

2011 cumulative 

total recoverable load 

EXPLANATION

Tenmile Creek main-stem sites 

Surface-water inflow 

Loads entering the 2011 

study reach upstream 

from site 0 (table 1)

Figure 11. Tracer-calculated zinc loads, upper Tenmile Creek drainage basin, Montana, September 2011.
Quantification of Trace-Element Loading 31

Rol19-0021_fig12

Site number (table 1; fig. 2)

Arsenic load, in micrograms per second

Distance downstream from injection point, in feet

0

4,000

2,000

6,000

10,000

8,000

12,000

14,000 0 6.75 10 15 17 23

0 1,000 2,000 3,000 4,000 5,000 6,000

−50

2011 dissolved load

2011 total recoverable load

2011 cumulative 

dissolved load 

2011 cumulative 

total recoverable load 

EXPLANATION

Tenmile Creek main-stem sites 

Surface-water inflow 

Loads entering the 2011 

study reach upstream 

from site 0 (table 1)

Figure 12. Tracer-calculated arsenic loads, upper Tenmile Creek drainage basin, Montana, September 2011.

Comparison of Relative Sources and Sinks of 

Trace-Element Loads between 2011 and 1998

Comparison of trace-element loads measured in the current study (2011) with those measured in 1998 was complicated by differences in hydrologic conditions between these 

years. In 1998, the streamflow in the study reach ranged from 

5.0 L/s at site 1 to 10.2 L/s at site 24 (Cleasby and Nimick, 

2002). In 2011, the streamflow ranged from 57.8 L/s at site 

1 to 96.4 L/s at site 24 (table 4). Furthermore, at the USGS 

streamgage upper Tenmile Creek near Rimini (06062500), 

the mean daily streamflow measured in water year 2011 was 

40.2 cubic feet per second, much higher than the mean daily 

streamflow of 17.1 cubic feet per second measured in water 

year 1998 (U.S. Geological Survey, 2016). The mean daily 

streamflow for the period of record from 1915 to 2011 was 

17.0 cubic feet per second, indicating that streamflow conditions in 1998 were about average and that 2011 conditions 

were well above average. The smaller streamflow volume and 

extremely dry antecedent conditions in 1998 resulted in traceelement loads that were substantially less than loads in 2011. 

In contrast, 2011 was wetter than normal, and the streamflow 

and discharge from the mine adits and other sources were 

much larger.

A comparison of the differences of cumulative totalrecoverable loads within the study reach, which is the cumulative downstream sum of all the sampled surface-water inflows, 

can be made between the two years. Subsurface inflows are 

not included in the determination of cumulative load, so the 

cumulative surface-water inflow load represents the minimum 

loading to the stream. Direct comparison of instantaneous 

loads and cumulative instantaneous loads of total-recoverable 

trace elements measured in 1998 versus 2011 (table 7) indicated that, although trace-element concentrations measured in 

2011 were less than those measured in 1998, instantaneous, 

total-recoverable trace-element loads were larger in 2011 at 

every site sampled in both years. Considering the total cumulative instream total-recoverable loads, copper and arsenic 

showed the largest increases in 2011 over 1998 (table 7); the 

total cumulative load of total-recoverable copper increased by 

560 percent, and the total cumulative load of total-recoverable 

arsenic increased by 735 percent across the study reach.

Upstream from the study reach at site 0 (fig. 2.), a portion 

of the streamflow and loads were diverted (city diversion) 

to the Ten Mile Water Treatment Plant in both 1998 and 

2011. Streamflow and loads upstream from the city diversion 

included the accumulation of all upstream sources. It is possible that streamflow in upper Tenmile Creek could have been 
32 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

augmented from storage in Scott Reservoir or from Banner 

Creek (fig. 1). These upstream sources of water could have 

been diverted into or away from upper Tenmile Creek. The 

origin and relative amount of the water entering upper Tenmile 

Creek from these upstream sources was unknown during this 

study. The 1998 loads were described in Cleasby and Nimick 

(2002), and the 2011 loads are listed in table 6.

Between sites 1 and 5, there was relatively little loading of streamflow and trace elements in both 1998 and 2011. 

Losses of total-recoverable cadmium, copper, and zinc loads, 

and small gains in total-recoverable lead and arsenic loads, 

were observed in both studies (table 7). Small contributions of 

total-recoverable lead to upper Tenmile Creek were observed 

at sites 1, 2, 4, and 5 in 2011, but, in 1998, only site 4 within 

this area showed a gain in the total-recoverable lead load. 

Losses in total-recoverable zinc also were found at these sites 

in 1998, but a substantial gain in the total-recoverable zinc 

load was observed at site 4 in 2011. Increases in total-recoverable arsenic were measured at sites 2 and 4 in both years, and 

the arsenic contributions to upper Tenmile Creek were greater 

in 2011.

Between the Lee Mountain Mine area and the Susie 

Lode adit (sites 7–14), trace-element loading in upper Tenmile 

Creek decreased between 1998 and 2011 for total-recoverable 

lead, increased slightly for total-recoverable cadmium, and 

increased substantially for total-recoverable copper, zinc, 

and arsenic. In 2011, instantaneous loads of total-recoverable 

cadmium, copper, zinc, and arsenic increased substantially just 

below the Lee Mountain Mine adit (at site 7). Despite overall 

gains in loads, small losses in some reaches were observed 

between sites 11 and 14 in the total-recoverable copper and 

arsenic loads between Lee Mountain Mine and Suzie Load 

adits in 1998, and greater losses were observed in 2011 for 

zinc and arsenic loads, primarily between sites 11 and 14.

In 1998, the Susie Lode adit (site 15) was the primary 

source of total-recoverable cadmium, zinc, and arsenic. During 

the 2011 study, the Susie Lode adit also was a primary source 

of these trace elements and copper. In 2011, the instantaneous load at site 16 (the next site downstream from the Susie 

Lode adit) increased from 223 μg/s (site 14) to 698 μg/s 

for total-recoverable cadmium, from 608 μg/s (site 14) to 

2,300 μg/s for total-recoverable copper, from 41,400 μg/s 

(site 14) to 89,100 μg/s for total-recoverable zinc, and from 

1,060 μg/s (site 14) to 9,400 μg/s for total-recoverable arsenic. 

A small increase in total-recoverable lead was observed at 

site 16 in 2011, and this increase was very slight at this site 

in 1998 (table 7). Trace-element loads generally decreased 

in 1998 from site 18 to the end of the study reach at site 24 

for total-recoverable cadmium, copper, lead, and arsenic. 

Loads of total-recoverable zinc in 1998 also decreased in 

this area between sites 16 and 22, but then notably increased 

again between sites 20 and 24. In 2011, instantaneous loads 

increased overall downstream from site 16 for total-recoverable cadmium, copper, and zinc. However, relatively large 

decreases were observed in 2011 at the most downstream site 

in the study reach (site 24) for instantaneous loads of totalrecoverable copper, lead, and arsenic.

The most notable differences in trace-element loadings 

between 1998 and 2011 was in the reach downstream from 

the Susie Lode adit from site 16 to site 24 at the bottom of 

the study area (table 7). In 1998, all the total-recoverable 

trace-element loads indicated substantial losses, whereas, in 

2011, all trace-element loads downstream from the Susie Lode 

adit increased. This increase in 2011 from 1998 conditions 

indicated that there were substantial contributions from traceelement sources in this area, through surface-water inflows or 

from resuspension of channel sediments, and the two surfacewater inflows in this reach, Spring Creek and Moore’s Spring 

Creek, contributed relatively small loads to upper Tenmile 

Creek. The load losses downstream from the Susie Lode adit 

in 1998 and the load gains in 2011 reflected differences in 

the hydrologic conditions between these years. In 1998, the 

streambed appeared to have acted as a sink, with dissolved 

trace elements precipitating from solution and sediment-associated trace elements falling out of the water column. In 2011, 

the increased stream velocity re-suspended the accumulated 

sediment and associated trace elements, which caused the 

reach downstream from the Susie Lode adit to act as a source 

of trace elements to the stream. Notably, the reach downstream 

from the Susie Lode adit contributed less than one-half of the 

total streamflow in 1998 and about 15 percent in 2011, indicating that groundwater discharge to upper Tenmile Creek during 

low streamflow conditions in this area was an important 

source of trace-element free water.
Quantification of Trace-Element Loading 33

Table 7. Instantaneous loads and cumulative instantaneous loads (in micrograms per second) of total-recoverable trace elements 

measured in main-stem surface-water samples, upper Tenmile Creek, Montana, 1998 and 2011.

[The adits are indicated at their relative site locations, but loads from these sites were not included. Surface-water inflow sites or sites sampled only in 2011 

are not included. Cumulative loads from 1998 include sites 0–24 in the lower reach. Sites were assigned short numbers (Site number), defined in table 1, 

and displayed on figure 2 (2011 only). bl, below; NA, data not available; ft, foot; ab, above]

Site Station description

Load

1998

Load

difference 

1998

Cumulative 

load 

1998

Load 

2011

Load 

difference 

2011

Cumulative 

load

2011

Cadmium

1 Tenmile Creek bl City Diversion at Rimini 

 (injection point) 7.03 NA NA 70.5 NA NA

2 Tenmile Creek 365 ft bl City Diversion at Rimini 7.03 0.00 7.03 69.4 −1.12 70.5

4 Tenmile Creek 695 ft bl City Diversion at Rimini 6.62 −0.41 7.03 68.8 −0.64 70.5

5 Tenmile Creek 1,115 ft bl City Diversion at Rimini 6.13 −0.49 7.03 68.9 0.10 70.6

6.8 Lee Mountain Mine adit Lee Mountain Mine adit

7 Tenmile Creek 1,780 ft bl City Diversion at Rimini 14.9 8.77 15.8 187 118 189

9 Tenmile Creek 1,985 ft bl City Diversion at Rimini 57.7 42.8 58.6 188 0.33 189

11 Tenmile Creek 2,120 ft bl City Diversion at Rimini 122 64.3 123 211 23.5 213

12 Tenmile Creek 2,420 ft bl City Diversion at Rimini 135 13.0 136 210 −1.65 213

13 Tenmile Creek ab Susie Lode Adit at Rimini 136 1.00 137 217 7.31 220

14 Tenmile Creek 3,015 ft bl City Diversion at Rimini 144 8.00 145 223 6.15 226

15 Susie Load adit Susie Load adit

16 Tenmile Creek 3,250 ft bl City Diversion at Rimini 271 127 272 698 475 702

18 Tenmile Creek 3,415 ft bl City Diversion at Rimini 216 −55.0 272 677 −21.4 702

19 Tenmile Creek 3,575 ft bl City Diversion at Rimini 210 −6.00 272 677 −0.25 702

20 Tenmile Creek bl Spring Creek at Rimini 205 −5.00 272 734 57.3 759

21 Tenmile Creek 4,180 ft bl City Diversion at Rimini 228 23.0 295 742 8.14 767

22 Tenmile Creek 4,675 ft bl City Diversion at Rimini 209 −19.0 295 745 3.23 771

24 Tenmile Creek 5,020 ft bl City Diversion at Rimini 183 −26.0 295 756 10.3 781

Percent increase in 2011 (versus 1998) at site 24 NA NA NA NA NA 165
34 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011

Table 7. Instantaneous loads and cumulative instantaneous loads (in micrograms per second) of total-recoverable trace elements 

measured in main-stem surface-water samples, upper Tenmile Creek, Montana, 1998 and 2011.—Continued

[The adits are indicated at their relative site locations, but loads from these sites were not included. Surface-water inflow sites or sites sampled only in 2011 

are not included. Cumulative loads from 1998 include sites 0-24 in the lower reach. Sites were assigned short numbers (Site number), defined in table 1, and 

displayed on figure 2 (2011 only). bl, below; NA, data not available; ft, foot; ab, above]

Site Station description

Load

1998

Load

difference 

1998

Cumulative 

load 

1998

Load 

2011

Load 

difference 

2011

Cumulative 

load

2011

Copper

1 Tenmile Creek bl City Diversion at Rimini 

(injection point) 33.6 NA NA 179 NA NA

2 Tenmile Creek 365 ft bl City Diversion at Rimini 32.2 −1.40 33.6 179 0.10 179

4 Tenmile Creek 695 ft bl City Diversion at Rimini 36.2 4.00 37.6 184 5.65 184

5 Tenmile Creek 1,115 ft bl City Diversion at Rimini 33.2 −3.00 37.6 178 −6.52 184

6.8 Lee Mountain Mine adit Lee Mountain Mine adit

7 Tenmile Creek 1,780 ft bl City Diversion at Rimini 42.3 9.10 46.7 402 225 409

9 Tenmile Creek 1,985 ft bl City Diversion at Rimini 110 67.7 114 431 28.8 437

11 Tenmile Creek 2,120 ft bl City Diversion at Rimini 295 185 299 527 95.5 533

12 Tenmile Creek 2,420 ft bl City Diversion at Rimini 326 31.0 330 566 39.1 572

13 Tenmile Creek ab Susie Lode Adit at Rimini 298 −28.0 330 615 48.7 621

14 Tenmile Creek 3,015 ft bl City Diversion at Rimini 288 −10.0 330 608 −6.92 621

15 Susie Load adit Susie Load adit

16 Tenmile Creek 3,250 ft bl City Diversion at Rimini 362 74.0 404 2,300 1,692 2,313

18 Tenmile Creek 3,415 ft bl City Diversion at Rimini 309 −53.0 404 2,270 −30.0 2,313

19 Tenmile Creek 3,575 ft bl City Diversion at Rimini 268 −41.0 404 2,300 30.0 2,343

20 Tenmile Creek bl Spring Creek at Rimini 296 28.0 432 2,470 170 2,513

21 Tenmile Creek 4,180 ft bl City Diversion at Rimini 292 −4.00 432 2,520 50.0 2,563

22 Tenmile Creek 4,675 ft bl City Diversion at Rimini 257 −35.0 432 2,810 290 2,853

24 Tenmile Creek 5,020 ft bl City Diversion at Rimini 244 −13.0 432 2,560 −250 2,853

Percent increase in 2011 (versus 1998) at site 24 NA NA NA NA NA 165
Quantification of Trace-Element Loading 35

Table 7. Instantaneous loads and cumulative instantaneous loads (in micrograms per second) of total-recoverable trace elements 

measured in main-stem surface-water samples, upper Tenmile Creek, Montana, 1998 and 2011.—Continued

[The adits are indicated at their relative site locations, but loads from these sites were not included. Surface-water inflow sites or sites sampled only in 2011 

are not included. Cumulative loads from 1998 include sites 0-24 in the lower reach. Sites were assigned short numbers (Site number), defined in table 1, 

and displayed on figure 2 (2011 only). bl, below; NA, data not available; ft, foot; ab, above]

Site Station description

Load

1998

Load

difference 

1998

Cumulative 

load 

1998

Load 

2011

Load 

difference 

2011

Cumulative 

load

2011

Lead

1 Tenmile Creek bl City Diversion at Rimini 

(injection point) 22.1 NA NA 99.4 NA NA

2 Tenmile Creek 365 ft bl City Diversion at Rimini 21.6 −0.50 22.1 100 0.63 100

4 Tenmile Creek 695 ft bl City Diversion at Rimini 56.0 34.4 56.5 105 4.87 105

5 Tenmile Creek 1,115 ft bl City Diversion at Rimini 34.7 −21.3 56.5 105 0.46 105

6.8 Lee Mountain Mine adit Lee Mountain Mine adit

7 Tenmile Creek 1,780 ft bl City Diversion at Rimini 95.4 60.7 117 201 95.1 201

9 Tenmile Creek 1,985 ft bl City Diversion at Rimini 215 120 237 224 23.2 224

11 Tenmile Creek 2,120 ft bl City Diversion at Rimini 215 0 237 240 16.3 240

12 Tenmile Creek 2,420 ft bl City Diversion at Rimini 215 0 237 240 0.02 240

13 Tenmile Creek ab Susie Lode Adit at Rimini 217 2.00 239 279 39.1 279

14 Tenmile Creek 3,015 ft bl City Diversion at Rimini 238 21.0 260 277 −2.08 279

15 Susie Load adit Susie Load adit

16 Tenmile Creek 3,250 ft bl City Diversion at Rimini 239 1.00 261 333 55.6 335

18 Tenmile Creek 3,415 ft bl City Diversion at Rimini 208 −31.0 261 325 −7.38 335

19 Tenmile Creek 3,575 ft bl City Diversion at Rimini 168 −40.0 261 323 −2.76 335

20 Tenmile Creek bl Spring Creek at Rimini 164 −4.00 261 353 30.3 365

21 Tenmile Creek 4,180 ft bl City Diversion at Rimini 164 0 261 327 −26.2 365

22 Tenmile Creek 4,675 ft bl City Diversion at Rimini 133 −31.0 261 389 62.0 427

24 Tenmile Creek 5,020 ft bl City Diversion at Rimini 142 9.00 270 343 −45.6 427

Percent increase in 2011 (versus 1998) at site 24 NA NA NA NA NA 58
36 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011

Table 7. Instantaneous loads and cumulative instantaneous loads (in micrograms per second) of total-recoverable trace elements 

measured in main-stem surface-water samples, upper Tenmile Creek, Montana, 1998 and 2011.—Continued

[The adits are indicated at their relative site locations, but loads from these sites were not included. Surface-water inflow sites or sites sampled only in 2011 

are not included. Cumulative loads from 1998 include sites 0-24 in the lower reach. Sites were assigned short numbers (Site number), defined in table 1, and 

displayed on figure 2 (2011 only). bl, below; NA, data not available; ft, feet; ab, above]

Site Station description

Load

1998

Load

difference 

1998

Cumulative 

load 

1998

Load 

2011

Load 

difference 

2011

Cumulative 

load

2011

Zinc

1 Tenmile Creek bl City Diversion at Rimini 

(injection point) 1,580 NA NA 17,200 NA NA

2 Tenmile Creek 365 ft bl City Diversion at Rimini 1,480 −100 1,580 16,700 -500 17,200

4 Tenmile Creek 695 ft bl City Diversion at Rimini 1,400 −80.0 1,580 16,900 200 17,400

5 Tenmile Creek 1,115 ft bl City Diversion at Rimini 1,310 −90.0 1,580 16,800 −100 17,400

6.8 Lee Mountain Mine adit Lee Mountain Mine adit

7 Tenmile Creek 1,780 ft bl City Diversion at Rimini 2,540 1,230 2,810 37,600 20,800 38,200

9 Tenmile Creek 1,985 ft bl City Diversion at Rimini 7,980 5,440 8,250 39,600 2,000 40,200

11 Tenmile Creek 2,120 ft bl City Diversion at Rimini 15,700 7,720 15,970 42,200 2,600 42,800

12 Tenmile Creek 2,420 ft bl City Diversion at Rimini 17,000 1,300 17,270 40,800 −1,400 42,800

13 Tenmile Creek ab Susie Lode Adit at Rimini 17,400 400 17,670 43,600 2,800 45,600

14 Tenmile Creek 3,015 ft bl City Diversion at Rimini 18,600 1,200 18,870 41,400 −2,200 45,600

15 Susie Load adit Susie Load adit

16 Tenmile Creek 3,250 ft bl City Diversion at Rimini 34,600 16,000 34,870 89,100 47,700 93,300

18 Tenmile Creek 3,415 ft bl City Diversion at Rimini 26,200 −8,400 34,870 87,400 −1,700 93,300

19 Tenmile Creek 3,575 ft bl City Diversion at Rimini 25,600 -600 34,870 88,100 700 94,000

20 Tenmile Creek bl Spring Creek at Rimini 24,700 -900 34,870 96,800 8,700 102,700

21 Tenmile Creek 4,180 ft bl City Diversion at Rimini 27,200 2,500 37,370 97,700 900 103,600

22 Tenmile Creek 4,675 ft bl City Diversion at Rimini 30,900 3,700 41,070 106,000 8,300 111,900

24 Tenmile Creek 5,020 ft bl City Diversion at Rimini 31,000 100 41,170 113,000 7,000 118,900

Percent increase in 2011 (versus 1998) at site 24 NA NA NA NA NA 189
Quantification of Trace-Element Loading 37

Table 7. Instantaneous loads and cumulative instantaneous loads (in micrograms per second) of total-recoverable trace elements 

measured in main-stem surface-water samples, upper Tenmile Creek, Montana, 1998 and 2011.—Continued

[The adits are indicated at their relative site locations, but loads from these sites were not included. Surface-water inflow sites or sites sampled only in 2011 

are not included. Cumulative loads from 1998 include sites 0-24 in the lower reach. Sites were assigned short numbers (Site number), defined in table 1, 

and displayed on figure 2 (2011 only). bl, below; NA, data not available; ft, feet; ab, above]

Site Station description

Load

1998

Load

difference 

1998

Cumulative 

load 

1998

Load 

2011

Load 

difference 

2011

Cumulative 

load

2011

Arsenic

1 Tenmile Creek bl City Diversion at Rimini 

(injection point) 35.1 NA NA 584 NA NA

2 Tenmile Creek 365 ft bl City Diversion at Rimini 45.2 10.1 45.2 596 11.9 596

4 Tenmile Creek 695 ft bl City Diversion at Rimini 61.1 15.9 61.1 616 20.8 616

5 Tenmile Creek 1,115 ft bl City Diversion at Rimini 51.1 −10.0 61.1 617 0.24 616

6.8 Lee Mountain Mine adit Lee Mountain Mine adit

7 Tenmile Creek 1,780 ft bl City Diversion at Rimini 71.5 20.4 81.5 842 225 841

9 Tenmile Creek 1,985 ft bl City Diversion at Rimini 104 32.5 114 957 115 957

11 Tenmile Creek 2,120 ft bl City Diversion at Rimini 123 19.0 133 904 −52.8 957

12 Tenmile Creek 2,420 ft bl City Diversion at Rimini 117 −6.00 133 895 −9.23 957

13 Tenmile Creek ab Susie Lode Adit at Rimini 118 1.00 134 1,040 145 1,102

14 Tenmile Creek 3,015 ft bl City Diversion at Rimini 112 −6.00 134 1,060 19.9 1,122

15 Susie Load adit Susie Load adit

16 Tenmile Creek 3,250 ft bl City Diversion at Rimini 1,480 1,368 1,502 9,400 8,340 9,462

18 Tenmile Creek 3,415 ft bl City Diversion at Rimini 1,040 −440 1,502 9,080 −320 9,462

19 Tenmile Creek 3,575 ft bl City Diversion at Rimini 839 −201 1,502 9,480 400 9,862

20 Tenmile Creek bl Spring Creek at Rimini 903 64.0 1,566 10,100 620 10,482

21 Tenmile Creek 4,180 ft bl City Diversion at Rimini 775 −128 1,566 10,000 −100 10,482

22 Tenmile Creek 4,675 ft bl City Diversion at Rimini 676 −99.0 1,566 12,600 2,600 13,082

24 Tenmile Creek 5,020 ft bl City Diversion at Rimini 662 −14.0 1,566 10,600 −2,000 13,082

Percent increase in 2011 (versus 1998) at site 24 NA NA NA NA NA 735
38 Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011 

Summary and Conclusions

The upper Tenmile Creek drainage basin in west-central 

Montana is typical of many headwater areas in the Western 

United States where acid drainage from mine lands has 

affected water quality. In 1998, a trace-element loading study, 

using tracer techniques and synoptic water-quality sampling, 

was conducted in a 9.8-mile reach of the creek near Rimini, 

Montana. Results of the 1998 study identified and quantified 

substantial loads of trace elements entering the approximately 

1-mile reach of upper Tenmile Creek that flows through the 

town of Rimini. Following remediation work that had been 

ongoing since 1998, a follow-up study was conducted in 2011 

by the U.S. Geological Survey in cooperation with the Montana Department of Environmental Quality within the 1-mile 

subreach of upper Tenmile Creek that flows through Rimini.

The two principal objectives of the current (2011) study 

were to identify and quantify the principal sources of traceelement loads entering a subreach of upper Tenmile Creek 

and to compare these results to those from 1998. Physical 

and chemical data were collected from 19 main-stem sites, 

8 surface-water inflow sites, and 8 groundwater monitoring 

wells on September 13 and 14, 2011. Trace-element loads 

in upper Tenmile Creek and surface-water inflow sites were 

quantified using streamflow data calculated using an injected 

dye tracer and water-quality data. Groundwater samples were 

collected to evaluate the diffuse loading to upper Tenmile 

Creek. Within the study reach that flows through Rimini, 

Mont., acid-mine drainage from the Lee Mountain Mine 

adit and the Susie Lode adit were identified as trace-element 

sources in the 1998 study.

In this study, streamflow in upper Tenmile Creek 

increased from 57.8 liters per second (L/s) at the tracer-injection point to 96.4 L/s at the lower end of the 5,020-foot study 

reach. Surface-water inflows accounted for about 15 percent 

of the increase, and subsurface inflow accounted for the rest. 

Current-meter measurements conducted in upper Tenmile 

Creek just upstream from the study reach indicated that about 

26 L/s of the 83.5 L/s streamflow in this area was diverted to 

the treatment plant. In 1998, streamflow upstream from the 

city diversion was 185 L/s, however only about 5 L/s was 

measured in upper Tenmile Creek downstream from the city 

diversion. Throughout the entire study reach, streamflow in 

1998 was about an order of magnitude less than the streamflow measured during the 2011 study.

Main stem trace-element concentrations were generally 

higher in 1998 than in 2011, but exceedances of the State of 

Montana human-health criteria were observed in upper Tenmile 

Creek in both studies. In 2011, the total-recoverable cadmium 

standard was exceeded downstream from the Susie Lode adit 

to the end of the study area but indicated a slight improvement over 1998. The standard for total-recoverable arsenic was 

exceeded throughout the study reach in both years. Total-recoverable zinc concentrations were less than the human-health 

standard for all sites in 2011 and were greater than the standard 

downstream from Beaver Creek through the end of the study 

reach in 1998. Throughout the study reach, acute aquatic-life 

criteria were exceeded at all main stem sites for cadmium and 

zinc in 1998 and 2011. Downstream from the Lee Mountain 

Mine adit, total-recoverable copper concentrations exceeded 

the chronic aquatic criterion in 2011, and main-stem concentrations exceeded the acute aquatic criterion throughout the study 

reach in 1998. Most main-stem sites exceeded the chronic 

aquatic-life criterion for lead in both years, and several sites 

also exceeded the acute criterion in 1998.

Groundwater level and water-quality data collected in the 

Lee Mountain area in 1998 indicated that a left-bank seep near 

the Lee Mountain Mine had the highest measured constituent 

concentrations of nearly all the samples collected that year. 

In 2011, trace-element concentrations in groundwater samples 

ranged from being like upper Tenmile Creek to being much 

greater than upper Tenmile Creek. Trace-element concentrations in wells from the right bank were generally lower than 

in those from the left bank. The pH in left-bank wells adjacent 

to the Lee Mountain Mine adit were acidic, and trace-element 

concentrations in left-bank wells were generally elevated compared to the right-bank wells adjacent to the streambed.

Loading over the entire study reach in 2011 increased 

elevenfold for total-recoverable cadmium, fourteenfold for 

total-recoverable copper, 3.5-fold for total-recoverable lead, 

sixfold for total-recoverable zinc, and eighteenfold for totalrecoverable arsenic. The largest source of trace elements was 

the Susie Lode adit, and the second largest source of traceelement loading to upper Tenmile Creek was the Lee Mountain Mine adit. Diffuse loading in the 1,770-feet stream reach 

just upstream from Spring Creek to the end of the study reach 

also contributed large amounts of total-recoverable cadmium, 

copper, zinc, and arsenic to upper Tenmile Creek.

Direct comparisons of trace-element loading to upper 

Tenmile Creek between 1998 and 2011 were complicated by 

the difference in hydrologic conditions. Streamflow throughout 

the study reach during the 1998 study was about 10 percent of 

the 2011 streamflow. However, analysis of the relative contributions of different sources to the total loading showed that the 

Lee Mountain Mine area and the Susie Lode adit were major 

trace-element contributors to upper Tenmile Creek in both 

years. The most notable difference in trace-element loading 

between 1998 and 2011 was the difference in loading between 

the Susie Lode adit and the end of the study reach. In 1998, all 

the total-recoverable trace-element loads showed a substantial 

loss in this reach despite the contribution of a larger proportion of the streamflow relative to 2011. In the current (2011) 

study, all the total-recoverable trace-element loads increased 

in this reach. Differences in trace-element loading between 

1998 and 2011 in this reach indicated that the streambed may 

act as either a source or sink for trace elements, depending on 

hydrologic conditions.
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For more information about this publication, contact:

Director, USGS Wyoming-Montana Water Science Center, Helena Office

3162 Bozeman Avenue

Helena, MT 59601

406–457–5990

For additional information, visit: https://www.usgs.gov/centers/wy-mt-water

Publishing support provided by the Madison and Rolla 

Publishing Service Centers
Cleasby and Eldridge—Quantification of Trace-Element Loading in the Upper Tenmile Creek Drainage Basin near Rimini, Montana, September 2011—Scientific Investigations Report 2019–5126

ISSN 2328-0328 (online)

https://doi.org/10.3133/sir20195126