science for a changing world

ofc

In cooperation with the

RAVALLI COUNTY BOARD OF COMMISSIONERS and the

BITTERROOT CONSERVATION DISTRICT

Hydrogeology and Aquifer Sensitivity of the 

Bitterroot Valley, Ravalli County, Montana

Water-Resources Investigations Report 99-4219

U.S. Department of the Interior 

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

U.S. Geological Survey

Hydrogeology and Aquifer Sensitivity of the 

Bitterroot Valley, Ravalli County, Montana

By David W. Briar and DeAnn M. Dutton

Water-Resources Investigations Report 99-4219

In cooperation with the

RAVALLI COUNTY BOARD OF COMMISSIONERS and the

BITTERROOT CONSERVATION DISTRICT
U.S. Department of the Interior 

BRUCE BABBITT, Secretary

U.S. Geological Survey

Charles G. Groat, Director

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

descriptive purposes only and does not imply endorsement by the 

U.S. Government

Helena, Montana 

February 2000

For additional information write to:

District Chief 

U.S. Geological Survey 

3162 Bozeman Avenue 

Helena, MT 59601-6456

Copies of this report may be purchased from:

U.S. Geological Survey 

Branch of Information Services 

Box 25286 

Denver, CO 80225-0286
CONTENTS

Page

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

Introduction......................................................................................^^ 2

Purpose and scope...................................................................................................................................................... 2

Previous investigations.............................................................................................................................................. 4

Location-numbering system....................................................................................................................................... 4

Acknowledgments............................................................................................_^ 4

Description of study area....................................................................................................................................................... 5

Physiography and drainage........................................................................................................................................ 5

Climate....................................................................................................................................................................... 6

Delineation of focus areas.......................................................................................................................................... 6

Hydrogeology........................................................................................................................................................................ 10

General geology......................................................................................................................................................^ 10

Hydraulic characteristics of basin-fill deposits.......................................................................................................... 12

Ground-water occurrence and movement.................................................................................................................. 14

Ground-water quality................................................................................................................................................. 21

Aquifer sensitivity................................................................................................................................................................^ 33

Summary and conclusions..................................................................................................................................................... 35

Selected refeiraces......................................................................................._ 37

Supplemental data.................................................................................................................................................................. 40

ILLUSTRATIONS

Figure 1. Map showing location of study area within the Bitterroot River drainage basin, Ravalli County, Montana... 3

2. Diagram showing location-numbering system.................................................................................................. 5

3. Map showing average annual precipitation in Ravalli County......................................................................... 7

4. Graph showing monthly precipitation for the study period and the mean monthly precipitation for the

1961-90 period of record at Hamilton, Montana......................................................................................... 8

5. Map showing locations of focus areas, inventoried wells, and surface-water sites, and corresponding

availability of water-quality analyses .......................................................................................................... 9

6. Map showing generalized surficial geology in the study area.......................................................................... 11

7. Boxplots showing range of static-water levels, yields, and specific capacities of wells based on

geologic unit and location............................................................................................................................ 13

8-10. Maps showing altitude of the water-level surface and location of monitoring wells in the:

8. Eightmile area, 1995 ................................................................................................................................ 16

9. Hamilton West area, 1995........................................................................................................................ 17

10. Hamilton Heights area, 1995 ................................................................................................................... 18

11. Map showing location of sediments, focus areas, and drainage areas upgradient from sediment

and focus areas............................................................................................................................................. 20

12. Boxplots showing specific conductance in well water grouped by location and geologic unit........................ 22

13. Boxplots showing nitrate concentration in well water grouped by location and geologic unit........................ 24

14. Graph showing nitrate concentration in well water versus depth to top of well casing open interval.............. 25

15-17. Maps showing distribution of nitrate concentration in well water from the:

15. Eightmile area, 1994-96........................................................................................................................... 27

16. Hamilton West area, 1994-96................................................................................................................... 28

17. Hamilton Heights area, 1994-96.............................................................................................................. 29

18. Graphs showing monthly variation in nitrate concentration in well water....................................................... 30

19. Modified trilinear diagram showing percentages of major ions in well water from the three focus areas....... 31

20. Graph showing population of Ravalli County by year, 1970-97 ...................................................................... 34

21. Hydrographs of water levels in wells of the monitoring network..................................................................... 69

CONTENTS iii
TABLES

Page

Table 1. Total annual precipitation in selected areas....................................................................................................... 19

2. Location and description of surface-water sites and one spring........................................................................ 32

3. Summary of specific conductance, nitrate concentration, well density, average precipitation, and

	percentage of wells completed in Tertiary alluvial-fan deposits in the three focus areas............................... 35

4. Records of selected wells................................................................................................................................... 41

5. Records of water levels in wells ........................................................................................................................ 54

6. Physical properties and major-ion concentrations for water from wells............................................................ 84

7. Trace-element and radon concentrations for water from wells.......................................................................... 106

8. Physical properties and major-ion concentrations for water from surface-water sites and one spring.............. 110

9. Trace-element concentrations for water from surface-water sites..................................................................... Ill

10. Physical properties and major-ion concentrations for deionized-water field blanks......................................... 112

11. Trace-element concentrations for deionized-water field blanks........................................................................ 113

12. Drinking-water regulations and guidelines for public water supply.................................................................. 114

CONVERSION FACTORS, VERTICAL DATUM, AND ABBREVIATED WATER-QUALITY UNITS

Multiply_________________By_______________To obtain

foot (ft) 

inch (in.) 

mile (mi)

acre

square mile (mi )

acre-foot (acre-ft)

acre-foot per year (acre-ft/yr) 

gallon per minute (gal/min) 

inch per year (in/yr)

foot per day 

[(ft3/d)/ft2 or ft/d]

gallon per minute per foot 

[(gal/min)/ft]

foot squared per day (f^/d) 

[((rWdyft^ftorfVVd]

Length

0.3048 

25.40 

1.609

Arcs

4,047

2.590

Volume

1,233

Flow

1,233 

0.06309 

25.40

Hydraulic Conductivity

0.3048

Specific Capacity

0.2070

Transmissivity

0.0929

meter (m) 

millimeter (mm) 

kilometer

square meter

square kilometer

cubic meter

cubic meter per year 

liter per second (L/s) 

millimeter per year

meter per day

liter per second per meter

meter squared per day

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

°C = 5/9(°F - 32) 

°F = 9/5(°C)+32

Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)~a geodetic datum derived from a general 

adjustment of the first-order level nets of both the United States and Canada, formerly called Sea Level Datum of 1929.

Abbreviated water-quality units used in this report: Acronyms used in this report:

Ug/L micrograms per liter GIS Geographic Information System

jaS/cm microsiemens per centimeter at 25 °C GWIC Montana Ground Water Information Center

mg/L milligrams per liter MBMG Montana Bureau of Mines and Geology

pCi/L picocuries per liter MCL Maximum Contaminant Level

NWQL USGS National Water Quality Laboratory

SMCL Secondary Maximum Contaminant Level

UM University of Montana

USGS U.S. Geological Survey

iv Hydrogeology and Aquifer Sensitivity of the Bitterroot Valley, Ravalli County, Montana
HYDROGEOLOGY AND AQUIFER SENSITIVITY OF 

THE BITTERROOT VALLEY, RAVALLI COUNTY, 

MONTANA

By David W. Briar and DeAnn M. Dutton 

Abstract

The population of the Bitterroot Valley in western Montana increased rapidly in the 1990s, creating 

concern about the potential for degradation of water in 

local aquifers. From August 1994 through October 

1997, the U.S. Geological Survey, in cooperation with 

the Ravalli County Board of Commissioners and the 

Bitterroot Conservation District, conducted a study of 

the aquifers underlying the Bitterroot Valley. This 

report describes the hydrogeology and assesses the sensitivity of the aquifers to degradation.

The 7-mile wide by 52-mile long Bitterroot Valley is drained by the north-flowing Bitterroot River, 

whose flood plain extends the length of the valley and 

is bounded by high terraces on the east and west. The 

valley is situated in a structural basin surrounded by 

intrusive, metasedimentary, metamorphic, and volcanic rocks. Tertiary sediments overlie bedrock and 

occur as two distinct geological units the ancestral 

Bitterroot River deposits, which generally are coarse 

grained, well sorted, and as much as 2,400 feet thick, 

and the overlying alluvial-fan deposits, which are composed of locally derived, poorly sorted erosional debris 

of the adjacent mountains. The bedrock and Tertiary 

sediments are overlain by Quaternary till, alluvial-fan 

deposits, alluvium, and terrace deposits.

Most wells in the Bitterroot Valley are completed 

in unconfined to semiconfined aquifers contained in 

Quaternary and Tertiary basin-fill deposits. On the 

basis of data from 9,424 wells, the shallowest staticwater levels and the largest values for yield and specific 

capacity typically are associated with wells completed 

in Quaternary deposits. Conversely, the deepest staticwater levels and smallest values for yield and specific 

capacity typically are associated with wells completed 

in Tertiary alluvial-fan deposits. Hydraulic characteristics of the ancestral Bitterroot River deposits are 

between these extremes. The hydraulic characteristics

of the aquifers did not vary significantly between the 

eastern and western sides of the valley.

Regionally, the direction of ground-water flow is 

from the mountain fronts along the basin margins 

toward the center of the basin and diagonally downvalley. Hydraulic gradients are steepest in the principal 

recharge areas near the mountain fronts and more gradual in discharge areas along the flood plain of the Bitterroot River. The basin-fill aquifers are recharged by 

infiltration of streamflow and irrigation water, subsurface inflow from bedrock, and direct infiltration of precipitation and snowmelt. Greater precipitation on the 

western side of the valley results in greater recharge 

there than on the eastern side of the valley. Groundwater discharge is by seepage to springs and streams, 

evapotranspiration, and withdrawals from wells.

Water in the basin-fill aquifers is primarily a calcium bicarbonate type. The median specific conductance of 240 ground-water samples was 246 

microsiemens per centimeter at 25 degrees Celsius and 

the median nitrate concentration in 239 samples was 

0.63 milligrams per liter as N. Samples from 20 wells 

had nitrate concentrations exceeding 3 milligrams per 

liter. The largest nitrate concentration was 5.9 milligrams per liter. Specific-conductance values and 

nitrate concentrations generally were greater on the 

east side of the valley. Nitrate concentration varied 

seasonally in water from 16 wells that were sampled 

approximately bimonthly for 1 year. The median radon 

concentration in 43 ground-water samples was 810 picocuries per liter; the concentration in 38 samples 

exceeded 300 picocuries per liter.

Although the relatively small nitrate concentrations indicate that the total nitrate load to the sampled 

aquifers has not resulted in nitrate concentrations that 

exceed recommended standards to date, some parts of 

the study area are more sensitive to degradation than 

others. The sensitivity of the area aquifers to nitrate 

loading is most strongly related to the total groundwater recharge-the greater the recharge, the less sensiAbstract
tive is the aquifer to nitrate loading. Ground-water 

recharge is directly related to the average annual precipitation and inversely related to the occurrence of 

low permeability surface deposits, such as Tertiary 

alluvial-fan deposits, in the respective area.

INTRODUCTION

The Bitterroot Valley is located in Ravalli 

County of western Montana (fig. 1). During the early 

1990s, the estimated population of Ravalli County 

increased at the fastest rate in the State (38 percent), 

changing from 25,075 in 1990 to 34,554 in 1997 (U.S. 

Bureau of the Census, issued annually). Most of the 

residents of Ravalli County live on the Bitterroot Valley floor within a few miles of the river. Much of the 

increase in population has been outside of established 

cities and towns and is generally concentrated in housing areas where each dwelling has its own well and septic system. Under unfavorable conditions, the local 

aquifers have the potential to become degraded owing 

to continued growth. However, sufficient data were not 

available to determine the effects of this growth and to 

identify the areas where the aquifer may be sensitive to 

potential degradation.

From August 1994 through October 1997, the 

U.S. Geological Survey (USGS), in cooperation with 

the Ravalli County Board of Commissioners and the 

Bitterroot Conservation District, conducted a study of 

the aquifers underlying the Bitterroot Valley. The 

study was designed to expand knowledge of the 

ground-water system through a systematic program of 

data collection, research, and analysis. The results of 

the study will be useful in developing a comprehensive 

management program for the use and protection of the 

ground-water resources of the Bitterroot Valley.

Purpose and Scope

This report describes the hydrogeology of the 

Bitterroot Valley and assesses the sensitivity of the 

aquifers underlying the benches along the west and east 

sides of the valley to degradation. Specific objectives 

were to:

1. Establish a ground-water-level and groundwater-quality monitoring network to obtain base-line 

information and to document changes in water levels 

and quality since previous studies.

2. Implement a geographically indexed, computer-based data framework to provide a basis for 

future assessment of effects from various ground-water 

management options.

3. Define ground-water flow paths, groundwater-recharge sources, and ground-water-discharge 

areas.

4. Characterize any potential sources of groundwater-quality degradation and identify areas with existing degradation.

The study was conducted at two different scales: 

a reconnaissance-level investigation of most of the valley floor and bench areas along the east and west margins of the valley, and a more detailed investigation of 

three "focus areas" on the benches. The reconnaissance-level investigation was designed to obtain baseline data in the valley where existing hydrologic data 

were sparse. Detailed investigations were aimed at 

areas undergoing development or likely to undergo 

development in the near future. The three focus areas, 

which were selected to be representative of specific 

hydrologic and physiographic settings in the valley, are 

all undergoing rapid residential development.

To determine the geometry and hydraulic properties of the basin-fill aquifers, and to identify any spatial 

trends in the data, a retrieval from the Montana Ground 

Water Information Center (GWIC) data base (Groundwater Information Center, Montana Bureau of Mines 

and Geology, unpub. data, 1996) was converted to geographic-information-system (GIS) format. This data 

base contains well-completion reports supplied by 

drillers for 9,424 wells in the study area. Water levels 

in 25 of these wells have been monitored quarterly by 

the Montana Bureau of Mines and Geology (MBMG) 

for the period 1993-96.

'A total of 263 wells were inventoried for this 

study and the information was entered into the USGS 

National Water Information System data base. When 

possible, data for these wells were cross-referenced 

with the GWIC data base. Water levels were measured 

in 221 of the wells. Fifty-four of the wells were 

selected a monitoring network, in which water levels 

were measured approximately bimonthly during the 

study. Specific conductance and water temperature 

were measured onsite at 240 wells, and water-quality 

samples were collected and analyzed for nitrate, chloride, and sulfate at 239 of these wells during the study. 

Additional data collected prior to this study and by

2 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
46

45°45

MILES

10 15 KILOMETERS

Base from Defense Mapping Agency digital data, 1:250,000, 1975, and

U.S. Geological Survey digital data, 1:100,000, 1983. Albers Equal Area

Conic Projection Standard parallels 44°00', and 48°00', central meridian -114°00'

Figure 1. Location of study area within the Bitterroot River drainage basin, Ravalli County, Montana.

FIGURE 1 3
MBMG are included in tables 4-7 in the Supplemental 

Data section at the back of this report.

Water samples were collected from 43 wells, 3 

streams, 1 irrigation canal, and 1 spring for laboratory 

analysis of major-ion and trace-element concentrations. Forty-three samples collected from wells were 

analyzed for radon. Results of an additional 24 waterquality analyses were obtained from MBMG for 22 of 

the 25 wells that they monitor in the study area and 

results of 26 analyses from previous USGS studies in 

the valley were included in the data tables.

Digital GIS datasets were compiled for the study 

area. Thematic layers compiled include hydrography, 

transportation, precipitation, public land survey, and 

digital elevation models. In addition, all project data 

were entered into the GIS data base to allow spatial 

analysis of the various data.

Previous Investigations

The USGS and MBMG conducted a study of the 

geology and water resources of the Bitterroot Valley 

from Florence south to Darby from 1955 to 1960 

(McMurtrey and others, 1972). The study included a 

detailed annual budget for surface water and a complete hydrologic budget for 1958 and 1959. Information compiled as part of the study included records of 

wells, multiple water-level measurements in about 30 

wells, water-quality analyses for 20 wells, and maps of 

basin-fill geology, water-table surface, and potential 

yield of wells. Norbeck (1980) presented a preliminary 

evaluation of deep aquifers in the valley based on test 

drilling of five wells in the valley, the deepest of which 

was 2,700 ft. Two recent University of Montana master's theses (Finstick, 1986; Uthman, 1988) have 

addressed the hydrogeology of parts of the Bitterroot 

Valley. These theses include information on monthly 

water levels in a series of observation wells and analyses of water samples collected from a network of wells. 

During 1991 and 1992, additional information collected by the USGS as part of a regional study (Clark 

and Dutton, 1996) included water levels in about 100 

wells and water-quality analyses for samples from 26 

wells. Water levels in five wells in the area have been 

measured at various intervals since 1960 as part of the 

USGS statewide monitoring network. Reports of additional investigations of the Bitterroot Valley are listed 

in the "Selected References" section at the back of this 

report.

Previous studies in the Bitterroot Valley provide 

information on the geologic history, surface-water 

quantity, and water-level fluctuations. However, the 

data are not sufficient to achieve the objects of this

study.

Location-Numbering System

In this report, wells, one spring, and surfacewater measurement sites are numbered according to 

geographic position within the rectangular grid system 

used for the subdivision of public lands (fig. 2). The 

location consists of as many as 14 characters. The first 

three characters specify the township and its position 

north (N) of the Montana Base Line. The next three 

characters specify the range and its position west (W) 

of the Montana Principal Meridian. The next two characters are the section number. The next three or four 

characters sequentially designate the quarter section 

(160-acre tract), quarter-quarter section (40-acre tract) 

quarter-quarter-quarter section (10-acre tract), and 

quarter-quarter-quarter-quarter section (2 1/2-acre 

tract), respectively, in which the well, spring, or surface-water site is located. The locations of subdivisions within a section are designated A, B, C, and D in 

a counterclockwise direction, beginning in the northeast quadrant. The final two characters are a sequence 

number assigned to differentiate multiple wells at a single site; for example, well 10N20W02ABBC01 (fig. 2) 

is the first well inventoried in the SW1/4NW1/4 

NW1/4NE1/4 of sec. 2, T. 10 N., R. 20 W.

Acknowledgments

The authors thank the members of the Bitterroot 

Water Forum a citizens' group addressing waterresource issues in the Bitterroot Valley for their support and interest during this study. In addition, we 

acknowledge the contribution of Ann M. Stewart, a 

graduate student from the University of Montana 

Department of Geology, who conducted much of the 

field work in the Eightmile focus area and assisted with 

water-quality sampling throughout the study area. 

Finally, we acknowledge the cooperation of the many 

landowners who provided access to their land and contributed valuable information about the occurrence and 

use of water resources in the Bitterroot Valley.

4 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Well 10N20W02ABBC01

Figure 2. Location-numbering system.

DESCRIPTION OF STUDY AREA

The Bitterroot Valley is situated in a north-trending intermontane basin in the Northern Rocky Mountains physiographic province (Fenneman, 1931). The 

valley is bordered on the west by the Bitterroot Mountains, on the east by the Sapphire Mountains, and on the 

southeast by the Anaconda Range (fig. 1). The valley 

averages about 7 mi wide and is about 52 mi long in the 

study area. Basin-fill sediments extend from near the 

confluence of the East and West Forks of the Bitterroot 

River in the southern part of the study area to the 

Ravalli County line north of Florence and encompass 

about 380 mi2, or about 16 percent of the 2,400 mi part 

of the drainage basin in Ravalli County.

Land use in the Bitterroot Valley historically has 

been dominated by irrigated agriculture with some dryland farming along the eastern margin. Most farms also 

have beef or dairy cattle and are smaller than 50 acres 

(McMurtrey and others, 1972). Currently, hay and pasture and some apple orchards are the main irrigated

crops. Dryland wheat and barley are grown on the eastern benches which are also used for rangeland (Kendy 

and Tresch, 1996). The conversion of agricultural land 

for residential development is the major land use 

change occurring in the Bitterroot Valley today.

Physiography and Drainage

The Bitterroot Valley contains two principal 

topographic features and related aquifers. In the center 

of the valley is the flood plain of the Bitterroot River, 

which generally is 1 to 2 mi wide and extends the 

length of the valley. Adjacent to the flood plain along 

the west and east sides of the valley are extensive high 

benches that range in width from 3 to 6 mi. These 

benches typically slope toward the flood plain at from 

4° or 5° near the basin margins to less than 1 ° near the 

flood plain. Benches on the east side of the basin have 

smooth topography and generally end in 50- to 150-ft 

scarps at the flood plain, whereas benches on the west 

side of the basin are dissected and merge gently with 

the flood plain. This report refers to all sediments east

Description of study area
of the Bitterroot River flood plain as east-side sediments and all sediments west of the Bitterroot River 

flood plain as west-side sediments. The Bitterroot Valley in the study area ranges in altitude from about 3,200 

ft where the Bitterroot River flows out of the study area 

on the north to about 5,500 ft on the highest terrace.

The major surface-water artery of the Bitterroot 

Valley is the Bitterroot River, which originates in the 

southern Bitterroot Mountains and the Anaconda 

Range and flows northward to its confluence with the 

Clark Fork about 15 mi north of the study area. About 

4 times as many tributaries join the river from the Bitterroot Mountains on the west as from the drier Sapphire Mountains on the east. Natural flows of the 

Bitterroot River and its tributaries typically peak in the 

spring, decline through the summer, and remain relatively stable through the winter. About 55 percent of 

the total annual streamflow in the river discharges in 

May and June in response to snowmelt and rainfall 

(McMurtrey and others, 1972). During the summer, 

irrigation withdrawals significantly reduce flow in the 

Bitterroot River and some of its tributaries; some 

reaches downstream from Hamilton routinely approach 

the minimum flows required to support fisheries (Nunnallee and Botz, 1976). However, part of the diverted 

water eventually drains back into the river system as 

irrigation return flow. The U.S. Soil Conservation Service (1947) estimated irrigation return flow to the Bitterroot River was about 280,000 acre-ft/yr when 

precipitation is normal, and about 216,000 acre-ft/yr 

when precipitation is below normal.

McMurtrey and others (1972) calculated water 

budgets for the Bitterroot River south of the Ravalli 

County line for water years 1958 and 1959. On average, 1,772,000 acre-ft/yr flowed into the basin. Of this 

total entry, 52 percent was from the west, 37 percent 

was from the south, and 11 percent was from the east. 

The average discharge of the Bitterroot River as it left 

the study area near Florence was 1,540,000 acre-ft/yr; 

thus, an estimated 232,000 acre-ft/yr, or 13 percent of 

the total surface-water inflow, was lost to irrigation, 

evapotranspiration, and other consumptive uses. Average annual streamflow at USGS gaging station 

12344000, Bitterroot River near Darby, was about 8 

percent greater during the present study period (water 

years 1994-97) than during the period analyzed by 

McMurtrey and others (1972).

Climate

The climate of the Bitterroot Valley is typical of 

mid-altitude intermontane basins of the Northern 

Rocky Mountains west of the Continental Divide, with 

cold winters, mild summers, and varied precipitation. 

On the basis of the 1961-90 period of record, the average annual precipitation at Hamilton (altitude 3,640 ft) 

is 13.28 in., and the average annual temperature is 44.8 

°F (National Oceanic and Atmospheric Administration, 1992). The average last occurrence of freezing 

temperatures is May 30, and the average first occurrence is September 10 (Natural Resources Conservation Service, U.S. Department of Agriculture, unpub. 

data., 1994). Thus, the average growing season is 

about 103 days long. Precipitation at higher altitudes 

of the Bitterroot Mountains along the western margin 

of the drainage basin is about 45 in/yr in the south and 

central parts of the valley and more than 80 in/yr in the 

north (fig. 3). In contrast, precipitation along the crest 

of the Sapphire Mountains on the eastern margin of the 

drainage basin is about 25 to 35 in/yr. Monthly precipitation for the study period and mean monthly precipitation for the period 1961 -90 at Hamilton are shown in 

figure 4.

Delineation of Focus Areas

To provide a more in-depth investigation of 

selected parts of the study area, three focus areas were 

chosen on the basis of physiography, geology, climate, 

effect of irrigation, and development pressure. These 

focus areas are referred to in this report as the Eightmile, Hamilton West, and Hamilton Heights areas 

(fig. 5).

The Eightmile area is located east of Florence 

and encompasses about 6.8 mi2 of the lower part of the 

Eightmile Creek drainage basin. The physiography of 

the area is dominated by the alluvial plain of Eightmile 

Creek, which is bounded on the north and south by low 

hills of Tertiary sediments. The geologic source area 

for the near-surface sediments in the Eightmile area is 

the Sapphire Mountains, which are composed predominantly of metasedimentary rocks (Tuck and others, 

1996). Precipitation in the area averages about 14 

in/yr. The maximum precipitation in the drainage area 

upgradient from the Eightmile Creek area is less than 

30 in/yr, making it the driest of the three focus areas. 

Limited diversion of Eightmile Creek locally supplies

6 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
46°15

45°45

EXPLANATION

-14- LINE OF EQUAL AVERAGE ANNUAL 

PRECIPITATION BASED ON 1961-90 

PERIOD OF RECORD -- Intervals 

4,10, and 20 inches.

15 MILES

15 KILOMETERS

Base from Defense Mapping Agency digital data, 1:250,000, 1975, and

U.S. Geological Survey digital data, 1:100,000, 1983. Albers Equal Area

Conic Projection Standard parallels 44° 00', and 48°00', central meridian -114°00'.

Figure 3. Average annual precipitation in Ravalli County. Digital precipitation data compiled by Oregon State University Climate Center 

(George Taylor, unpublished data, 1995).

FIGURE 3 7
CO A LU 4

o

3

I 2

cr 

o_

i i i i n i i i i i i i i i i i i i i i i \ i i i i i i i i i i

ASONDJFMAMJJASOND JFMAMJJASOND

1994 1995 1996

JFMAMJJASO 

1997

EXPLANATION

CH MONTHLY PRECIPITATION DURING STUDY 

PERIOD (AUG 1994-OCT 1997)

 MEAN MONTHLY PRECIPITATION FOR 

1961-90 PERIOD OF RECORD

Figure 4. Monthly precipitation for the study period and the mean monthly precipitation for the 1961-90 period of record at Hamilton, 

Montana. Data from the Western Regional Climate Center, Desert Research Institute, Reno, Nev., 1999.

some water for irrigation. The Bitterroot Irrigation 

District Canal terminates south of, and therefore does 

not provide irrigation water to, the Eightmile area.

The Hamilton West area is located just northwest 

of Hamilton and encompasses about 19.4 mi2. The 

Tertiary benches in the Hamilton West area have been 

intensively dissected by streams emanating from the 

Bitterroot Mountains, and the resulting valleys contain 

Quaternary alluvial-fan deposits and glacial outwash. 

The principal geologic source area for the near-surface 

sediments in the Hamilton West area is igneous rocks 

of the Bitterroot Mountains (Tuck and others, 1996). 

Precipitation in the area ranges from about 14 in/yr 

near the flood plain of the Bitterroot River to about 26 

in/yr at the mountain front. Precipitation in parts of the 

drainage area upgradient from the Hamilton West area 

is more than 60 in/yr. During the irrigation season 

nearly all water from local streams is diverted for 

growing crops.

The Hamilton Heights area is located northeast 

of Hamilton and encompasses about 19.2 mi2. The

Tertiary benches in the Hamilton Heights area are less 

dissected by streams than those in the Hamilton West 

area, and large areas of the gently sloping bench surface remains. The geologic source area for most of the 

near-surface sediments underlying the area is the Sapphire Mountains, which are composed primarily of 

metasedimentary rocks. Precipitation in the area 

ranges from about 14 in/yr near the flood plain of the 

Bitterroot River to about 18 in/yr along the Sapphire 

Mountains to the east of the area. Maximum precipitation in the drainage area upgradient from the Hamilton 

Heights area is about 35 in/yr. The Hamilton Heights 

area is the only focus area that receives irrigation water 

from outside its natural drainage area. Water for irrigation is supplied primarily by the Bitterroot Irrigation 

District Canal (fig. 5), which transports water from 

Lake Como in the Bitterroot Mountains northwest of 

Darby to most of the benches on the east side of the valley. Water for irrigation is also supplied by the Republican and Hedge Ditches (fig. 17), which divert water 

from the Bitterroot River south of Hamilton. The

8 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
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T.9N.

T.8N.

T.7N.

T.6N.

46°15'

T.5N.

T.4N.

T.3N.

T.2N.

Hamilton Heights - 

area tfigs. '& r7J*^

R.22W. R.21W.

EXPLANATION

BOUNDARY OF FOCUS AREA

INVENTORIED WELLS

Major-ion concentrations 

available (table 6)

Major ion concentrations 

not analyzed

SURFACE-WATER SITES AND SPRING

Major ion concentrations 

available (table 8)

Base from Defense Mapping Agency digital data, 1:250,000, 1975, and

U.S. Geological Survey digital data, 1:100,000, 1983. Albers Equal Area

Conic Projection Standard parallels 44° 00', and 48°00', central meridian -114°00'.

6 MILES

6 KILOMETERS
canals transport water from about mid-April through 

October.

HYDROGEOLOGY

Ground-water flow in the Bitterroot Valley is 

strongly controlled by the depositional history, topographic setting, and hydraulic character of the geologic 

units in the area. Recent work by Lonn and Sears 

(1998) indicates that the basin-fill geology of the Bitterroot Valley includes extensive coarse-grained, 

water-yielding deposits that are not found in other 

basins in southwest Montana.

General Geology

The Bitterroot Valley is situated in a structural 

basin most probably formed by crustal extension during the middle Eocene Epoch (Hodges and Applegate, 

1993). Gravity data indicate a distinct, relatively 

straight western basin margin along the Bitterroot 

Mountains, in contrast to an irregular eastern margin 

along the Sapphire Mountains (Noble and others, 

1982). Gravity and magnetic data indicate that basinfill sediments attain a maximum thickness of at least 

3,000 ft near Corvallis and Hamilton (Noble and others, 1982; Crosby, 1976). A surficial geology map of 

the study area is presented as figure 6.

Intrusive, metasedimentary, metamorphic, and 

volcanic rocks border the Bitterroot Valley. West and 

south of the basin, the Bitterroot, Anaconda, and southern Sapphire Mountains are composed of Cretaceous 

granitic rocks associated with the Idaho Batholith. 

These rocks are mostly gray quartz monzonite with 

some granodiorite and anorthite. Along the western 

basin margin, the granitic rocks are bordered by gneiss, 

which averages about 2,000 ft thick. East of the basin, 

the Sapphire Mountains are composed mostly of 

metasedimentary rocks of the Middle Proterozoic Belt 

Supergroup that include quartzites, quartzitic and calcareous argillite, and argillaceous limestone. Tertiary 

volcanic rocks, ranging in composition from acidic to 

basic, crop out locally near fault zones along basin margins (McMurtrey and others, 1972).

Tertiary sediments overlie bedrock throughout 

the basin and crop out on the eastern and, to a lesser 

extent, western benches. Tertiary sediments also occur 

at depth beneath the benches, beneath a veneer of Quaternary alluvium along the Bitterroot River flood plain,

and beneath Quaternary alluvial fans along the floors of 

tributary valleys. These unconsolidated to semiconsolidated Tertiary deposits are composed of gravel, sand, 

silt, and clay that occur as two distinct geologic units: 

the ancestral Bitterroot River deposits and the Sixmile 

Creek Formation (Lonn and Sears, 1998).

The ancestral Bitterroot River deposits the 

lower of the two Tertiary units in the basin are composed of well-sorted, well-rounded, well-stratified, 

light-gray to white cobbles, gravel, and sand that are 

locally interbedded with silt and clay (Lonn and Sears, 

1998). Clast lithologies are representative of rocks 

from the entire drainage basin, with several distinctive 

clast types indicating transport from the far southwestern end of the basin and possibly even beyond. The 

remote source area for many of the rocks, the wellsorted and well-stratified nature of the deposit, and the 

age dates of ash and gneiss pebbles of 39 and 45 million 

years, respectively, indicate that the ancestral Bitterroot 

River deposits were most likely deposited by a northward through-flowing river of regional scale during the 

middle Eocene to middle Miocene Epochs (James 

Sears, Department of Geology, University of Montana, 

written commun., 1997). Deep drill holes show that 

unconsolidated sediments similar to the ancestral Bitterroot River deposits are as much as 2,400 ft thick in 

places (Norbeck, 1980).

The Sixmile Creek Formation, which overlies 

the ancestral Bitterroot River deposits, is composed of 

brown, unconsolidated to weakly lithified, poorly 

sorted, moderately stratified, subangular to rounded 

boulders and cobbles in a sandy silt and clay matrix 

deposited in alluvial-fan environments. These sediments represent the locally derived, poorly sorted erosional debris of the adjacent mountains deposited in 

arid conditions during the late Miocene and Pliocene 

Epochs, when flash floods are thought to have transported loose rock and soil from adjacent canyons in 

massive mud-rock slurries. This formation is identified 

as Tertiary alluvial-fan deposits in figure 6. The 

Sixmile Creek Formation contains abundant brown, 

massive, micaceous silt beds and clasts commonly 

coated by iron oxide or caliche (Lonn and Sears, 1998). 

Bedding typically dips more steeply than the present 

surfaces of these deposits; therefore, the present surfaces represent erosional pediment surfaces.

Quaternary glacial till underlies many of the high 

benches along the Bitterroot Mountains, especially in 

the southern part of the study area west of Darby.

10 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
O

o

I 

I

w

I 

O

5]

OQ

3

3-

T.1ON.

T.9N.

T.8N.

T.7N.

T.6N.

46°15' T--

T.5N.

T.4N.

T.3N.

T.2N.

R.22W. R.21W.

Modified from Lonn and Sears (1998)

R.20W. R.19W. R.18W.

EXPLANATION

Qalt-- Quaternary alluvium 

and terrace deposits

Qaf-- Quaternary alluvial-fan 

deposits

Qgt- - Quaternary glacial till

Taf Tertiary alluvial fan 

deposits (Sixmile Creek 

Formation)

Tabr- - Tertiary ancestral 

Bitterroot River deposits

TYb Tertiary through Middle 

Proterozoic bedrock

Contact

6 MILES

6 KILOMETERS
These unsorted, unstratified deposits consist of 

boulders, cobbles, gravel, sand, silt, and a large 

amount of clay (Lonn and Sears, 1998). Moraines 

indicate at least three stages of glaciation beginning in 

early Pleistocene (Weber, 1972).

Quaternary alluvial-fan deposits are present 

along much of the western side of the valley and along 

the larger tributary streams on the eastern side of the 

valley. These unconsolidated deposits are composed of 

well-rounded, unweathered cobbles and boulders in a 

matrix of sand and gravel that were locally derived 

from bedrock and the reworking of older unconsolidated sediments (Lonn and Sears, 1998). These fans 

were deposited in braided stream environments and are 

generally less than 40 ft thick (McMurtrey and others, 

1972). Sorting and grain size decrease with distance 

from the mouths of tributary canyons. On the western 

side of the valley, Quaternary alluvial-fan deposits 

include abundant glacial outwash.

Quaternary alluvium and terrace deposits occur 

along the present flood plain of the Bitterroot River. 

Alluvium underlies the flood plain of the Bitterroot 

River and the channels of its major tributaries. Well 

logs indicate the alluvium has an average thickness of 

40 ft (McMurtrey and others, 1972). Quaternary terraces occur adjacent to and 10 to 30 ft above the Bitterroot River flood plain. Both the alluvium and the 

terrace deposits are composed of material essentially 

indistinguishable from reworked material of the ancestral Bitterroot River deposits (Lonn and Sears, 1998).

Hydraulic Characteristics of Basin-Fill 

Deposits

Most wells in the Bitterroot Valley are completed 

in basin-fill deposits of Quaternary and Tertiary age. 

The bedrock surrounding and underlying the basin is 

not a major aquifer, although wells completed in bedrock may yield small amounts of water from fractures 

and weathered zones.

Aquifers in the various basin-fill deposits are 

either unconfined, semiconfined, or confined. Most 

aquifers in Quaternary alluvium, terrace deposits, and 

alluvial-fan deposits are unconfined to semiconfined 

and yield abundant water to wells. These deposits can 

best be described as a sequence of complexly stratified 

lenses of cobbles, gravel, and sand with varying 

amounts of intercalated silt and clay. The greater the 

percentage of silt and clay, the greater the likelihood

that the aquifer will be semiconfined. In some parts of 

the study area, aquifers in Quaternary alluvial-fan 

deposits are confined by overlying till.

Abundant fine-grained layers within Tertiary 

alluvial-fan deposits of the Sixmile Creek Formation 

confine water in more permeable layers. With depth, 

these fine-grained layers become more consolidated 

and, therefore, less permeable. Aquifers in the Tertiary 

ancestral Bitterroot River deposits range from unconfined where exposed at the surface to confined where 

overlain by till or Tertiary alluvial-fan deposits. 

Although present in relatively small percentages in the 

ancestral Bitterroot River deposits, silt and clay form 

confining layers at depths greater than a few hundred 

feet.

Although some Tertiary deposits contain productive aquifers, knowledge of the extent and hydraulic 

character of these water-yielding zones is limited. 

Aquifers in Quaternary and Tertiary deposits within the 

basin generally are assumed to be hydraulically connected, with local exceptions.

To assess certain hydraulic characteristics of the 

geologic units in the valley, the GWIC data base for the 

study area (9,424 wells as of 1994) was input to a GIS 

and combined with the geologic map data shown in figure 6 to enable the assignment of a geologic unit to each 

well. Several assumptions were made during the process of assignment. Wells that were deeper than 40 ft 

and located in map areas identified as Quaternary alluvium and terrace deposits, Quaternary alluvial-fan 

deposits, or Quaternary glacial till were assumed to be 

completed in the underlying ancestral Bitterroot River 

deposits. Likewise, wells that were deeper than 300 ft 

and located in map areas identified as Tertiary alluvialfan deposits were assumed to be completed in the 

underlying ancestral Bitterroot River deposits. The 

resulting GIS data base was used to produce statistics 

characterizing the depth to static-water level, yield, and 

specific capacity of wells completed in various geologic units and in various areas of the valley (fig. 7).

Depth to static-water level represents the depth 

to the water table in an unconfined aquifer and the pressure head in a confined aquifer. An unconfined aquifer 

with a shallow depth to water is generally more economical to develop given the shallow well-completion 

depth required, but is also more vulnerable to contamination from surface sources than an aquifer with a 

greater depth to water. The depth to static-water level

12 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
2 

cRT

i 

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£ 

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tatic-wa

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2.

S

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o

I

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SPECIFIC CAPACITY, IN GALLONS 

PER MINUTE PER FOOT

STATIC-WATER LEV

BELOW LAND SU

 ' w o> co ro c O W O> CO tOO O O O O C

Qalt QfTabrYb 

EXPLANATION

(772) Number ofobservations GEOLOGIC UNIT

i ----- 90th percentile Qalt-Quaternary alluvil

X.. StSSEKSE I - Median Tabr-Tertiary ancestra 

1 _ \ __.. ... TYb-Tertiary through ^

*-| ',- -25th percentlle J a

'---- 10th percentile

I^Hll » ? JJ^/5 52. 3 ?

Qaf Tabr

deposits

ile CreekFormation) deposits 

ic bedrock

i i i i i i i . i i i

H

I \ N

1 1 j3

IT] 1

, . i . i i , , i . .

i i i i i i i i i i i

o-l

03~1

i . i , i i . i i i i

i i . . , . i i i i 

i i i i , i . i i . ,

i i i . , i . i i i

-1 1 1 . to

1 1 ...... 1 CO

"" "'"" O)

ni 1 

on 1

i . i , i i i i i , ,

n i "3 -LLJ s

in 1

' ' '.' ' ' ' ' ' 1 '

 m 1

-m |

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3 S 8 

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fn 1

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in a confined aquifer generally is not definitively 

related to the depth of the water-bearing strata.

Well yield is dependent on the capacity of the 

installed pump, the efficiency of the well, and the ability of the aquifer to supply water to the well. Domestic 

well yields of less than 10 gal/min are probably indicative of poor aquifers.

Specific capacity is an expression of the productivity of a well obtained by dividing the well yield by 

the pumping-induced drawdown in the well. For 

example, a well that yielded 10 gal/min with 5 ft of 

drawdown would have a specific capacity of 2 gal/min 

per foot of drawdown. This well would be twice as productive as a well that yielded the same 10 gal/min but 

had a pumping-induced drawdown of 10 ft resulting in 

a specific capacity of 1 gal/min per foot. Specific 

capacity is dependent on both the efficiency of the well 

and the ability of the aquifer to supply water to the well. 

Assuming that most domestic wells in the study area 

have similar efficiencies and that variations in well 

efficiency are randomly distributed throughout the 

study area, differences in specific-capacity values 

reported in this analysis could be attributed to differences in the water-yielding capability of the various 

basin-fill deposits in which the wells are completed.

One limitation of this analysis deserves noting. 

The GWIC data base contains information about the 

vast majority of wells completed in the study area but 

does not contain information about "dry holes" or wells 

that were never completed because insufficient yield 

made them unsuitable for their intended use. Therefore, statistics shown in figure 7 for wells completed in 

geologic units that are relatively poor aquifers such as 

the Tertiary alluvial-fan deposits might overestimate 

the median yield and specific capacity of the aquifer.

Wells completed in Quaternary alluvium and terrace deposits had the shallowest static-water levels and 

the largest values of yield and specific capacity of all 

geologic units analyzed. These conditions are most 

likely due to the well-sorted, coarse-grained character 

of the deposits and their occurrence along the main Bitterroot River flood plain, which is the primary groundand surface-water discharge area for the valley. On the 

basis of 12 aquifer tests for Quaternary alluvium and 

terrace deposits, McMurtrey and others (1972) calculated transmissivity values ranging from 2,000 to 

38,000 ft2/d.

Wells completed in Quaternary alluvial-fan 

deposits had static-water levels essentially identical to

those for Quaternary alluvium and terrace deposits, but 

had smaller values for yield and specific capacity. 

These smaller values are most likely related to the Quaternary alluvial-fan deposits being less well-sorted and 

finer grained than the alluvium and terrace deposits.

In contrast to wells completed in Quaternary 

deposits, wells completed in Tertiary alluvial-fan 

deposits had the deepest static-water levels and smallest values of yield and specific-capacity of all geologic 

units analyzed. The deep static-water levels in the Tertiary alluvial-fan deposits are due largely to thenpresent topographic position high on the basin margins 

above the altitude of tributary streams that supply 

recharge to the Quaternary deposits. The small values 

for yield and specific capacity of wells completed in 

Tertiary alluvial-fan deposits result from their finegrained, poorly sorted character and substantial postdeposition compaction, cementation, and weathering, 

which further reduce permeability.

Wells completed in the ancestral Bitterroot 

River deposits had values for static-water level, yield, 

and specific capacity between those for Quaternary 

deposits and those for Tertiary alluvial-fan deposits. 

The range in static-water levels in these wells can 

largely be explained by the topographic position of the 

parts of the formation that wells penetrate generally 

higher in altitude than the Quaternary deposits but 

lower in altitude than the Tertiary alluvial-fan deposits. 

The range in values for yield and specific capacity is 

due largely to the permeability of the deposits which, 

owing to compaction with time, is less than the permeability of Quaternary deposits but greater than the permeability of the poorly sorted, silt- and clay-rich 

Tertiary alluvial-fan deposits. Hydraulic-conductivity 

values for five aquifer tests presented by Norbeck 

(1980) for two deep test wells (2,627 and 1,110 ft) completed in the ancestral Bitterroot River deposits range 

from 2.6 to 6.2 ft/d, which are within the range of 

expected values for silty to clean sand (Freeze and 

Cherry, 1979). Based on the geologic origin of these 

sediments, the deep test-well data, and the extensive 

statistical summary provided by the GWIC data base 

analysis, the ancestral Bitterroot River deposits are 

likely to be a productive aquifer at most locations or 

depths in the study area.

Ground-Water Occurrence and Movement

Regionally, the direction of ground-water flow in 

the Bitterroot Valley is from the mountain front along

14 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
114°02'30"

46°38'30"

T. 10 N.

46°37'30" -

R. 20 W. R. 19 W.

Base from U.S. Geological Survey digital data, 1:24,000, 1979 to present. 

Albers Equal Area Conic Projection Standard parallels 44°00', and 48°00', 

central meridian -114° 00'

0.25 0.5 0.75 1 MILE

0.25 0.5 0.75 1 KILOMETER

EXPLANATION

GENERAL WATER-LEVEL CONTOUR-Shows altitude at which 

water level would have stood in 

tightly cased wells completed in 

various unconsolidated geologic 

units, August-December 1995 

(table 4). Dashed where approximately located. Contour interval 25 

feet. Datum is sea level

SHALLOW WATER-YIELDING ZONES 

ABSENT

INVENTORIED WELL

 Well in water-level

monitoring network

? Well in water-level and 

nitrate monitoring 

networks

o Well not in monitoring 

network

3,413 MEASURED ALTITUDE OF WATER 

LEVEL; -, no data for AugustDecember 1995.

Figure 8. Altitude of the water-level surface and location of monitoring wells in the Eightmile area, 1995.

16 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
the basin margins toward the center of the basin and 

diagonally downvalley (Briar and others, 1996). The 

configuration of the water-level surface generally 

reflects topography, with steeper hydraulic gradients 

in the recharge areas along the mountain front than in 

discharge areas along the flood plain of the Bitterroot 

River. The direction of flow in deeper aquifers might 

be somewhat different owing to confining strata, 

faulting, or other deep structural controls (Briar and 

others, 1996).

Water levels were measured approximately 

bimonthly in most of the 54 wells of the monitoring 

network (table 5 and figure 21 in the Supplemental 

Data section at the back of this report). The altitudes of 

monitoring wells in the Eightmile area were determined to within + 0.5 ft by instrument leveling from 

points of known altitude. The altitude of land surface 

at monitoring wells in the Hamilton West and Hamilton 

Heights areas was determined from l:24,000-scale 

topographic maps and is accurate to within about onehalf the contour interval (±10 ft).

The configuration of the water-level surface in 

the three focus areas was determined from water levels 

measured from August through December 1995 (figs. 

8-10). Water-levels were manually contoured at a scale 

of 1:24,000. Topography and the altitude of streams 

and springs were used to position contours between 

data points. The direction of ground-water flow is perpendicular to the water-level contours and downgradient.

The contours shown in figures 8-10 represent 

water levels in the depth interval of basin fill in which 

most wells in the area are completed. Water levels vary 

with well depth in areas having a vertical component of 

ground-water flow. Recharge areas along the basin 

margins commonly have a downward component of 

flow, whereas discharge areas near streams and rivers 

in the central parts of the basin have an upward component of flow. Consequently, water-level measurements 

in individual wells might differ from water levels 

shown in the figures by tens of feet in some areas. In 

addition, wells may be completed at different depths 

and open to different water-yielding zones. For example, well 10N19W06DDCC01 has a water-level altitude in figure 8 of 3,241 feet which differs from the 

adjacent contours by 60-80 feet. This well is completed in a deeper water-yielding zone than adjacent 

wells.

Water-level contours reflect recent hydrologic 

conditions and development. Seasonal water-level 

fluctuations in most wells typically range from a few 

feet to a few tens of feet but do not significantly change 

the location or shape of the water-level contours at the 

scale shown. Quarterly water-level data dating back to 

the late 1950's for three wells (10N20W13ABA01, 

08N20W19BAAD03,08N19W07CBBD01) in the Bitterroot River flood plain near Florence and Hamilton 

are not significantly different from present conditions. 

However, changes in irrigation practices and increased 

withdrawals for domestic use have probably had some 

effect on water levels in the bench areas. Unfortunately, insufficient data are available to determine 

long-term changes in ground-water levels throughout 

most of the study area.

Basin-fill aquifers in the Bitterroot Valley are 

recharged by infiltration of streamflow and irrigation 

water, subsurface inflow from surrounding bedrock 

(which is primarily recharged by melting snowpack), 

and direct infiltration of precipitation and snowmelt. 

Discharge from basin-fill aquifers is by seepage to 

springs and streams, evapotranspiration, withdrawals 

by wells, and subsurface flow to the north out of the 

basin.

The potential for natural ground-water recharge 

to an area is dependent upon the quantity of precipitation that falls on and upgradient from the area. For this 

discussion, the total area receiving precipitation which 

could potentially recharge an aquifer through direct 

infiltration, inflow from bedrock, and leakage from 

streams, is referred to as the "potential recharge source 

area." As shown in figure 3, the west side of the Bitterroot Valley receives significantly more precipitation 

than the east side. The potential recharge source area 

on the west side is 415,673 acres; this area includes 

upgradient bedrock and sedimentary deposits on the 

western side of the valley (areas A and B in fig. 11) and 

extends from near the confluence of the East and West 

Forks of the Bitterroot River in the south to the Ravalli 

County line in the north. This potential recharge source 

area was combined with the precipitation data presented in figure 3 using a GIS. The analysis indicates 

that west-side sediments and bedrock receive a total of 

1,462,586 acre-ft/yr of precipitation, for an average 

annual rate of 3.52 ft (42.22 in.) (table 1). In contrast, 

the potential recharge source area on the east side is 

333,560 acres; this area includes upgradient bedrock

Hydrogeology 15
R. 21 W. R. 20 W.

T. 7N. 

T. 6N.

1

vo

>

Io 

o

Cu §"

46°17'30"

46°15'

£

O

o

ffi

vc ^

Base from U.S. Geological Survey digital data, 1:24,000, 1979 to present. 

Albers Equal Area Conic Projection Standard parallels 44°00', and 48°00', 

central meridian -114° 00'.

0.25 0.5 0.75 1 MILE

EXPLANATION

GENERAL WATER-LEVEL CONTOUR-Shows altitude at which 

water level would have stood in 

tightly cased wells completed in 

various unconsolidated geologic 

units, August-December 1995 

(table 4). Dashed where approximately located. Contour interval 50 

feet. Datum is sea level

0 0.25 0.5 0.75 1 KILOMETER

INVENTORIED WELL

 Well in water-level

monitoring network

it Well in water-level and 

nitrate monitoring 

networks

o Well not in monitoring 

network

3,563 MEASURED ALTITUDE OF WATER 

LEVEL; -, no data for AugustDecember 1995

114°05' 114°02'30" R. 20 W. R. 19 W.

46°18'30" ~

46°17'30"

Base from U.S. Geological Survey digital data, 1:24,000, 1979 to present. 

Albers Equal Area Conic Projection Standard parallels 44°00', and 48°00', 

central meridian -114° 00'.

3,484

EXPLANATION

GENERAL WATER-LEVEL CONTOUR--Shows altitude at which 

water level would have stood in 

tightly cased wells completed in 

various unconsolidated geologic 

units, August-December 1995 

(table 4). Dashed where approximately located. Contour interval 50 

feet. Datum is sea level

INVENTORIED WELL

Well in water-level 

monitoring network

Well in water-level and 

nitrate monitoring 

networks

Well not in monitoring 

network

MEASURED ALTITUDE OF WATER 

LEVEL; -, no data for AugustDecember 1995

0.25 0.5 0.75 1 MILE

0 0.25 0.5 0.75 1 KILOMETER

Figure 10. Altitude of the water-level surface and location of monitoring wells in the Hamilton Heights area, 1995.

FIGURE 10 18

Table. 1 Total annual precipitation in selected areas

Area 

(see fig. 11)

West-side sediments and bedrock (A + B)

East-side sediments and bedrock (C + D)

Eightmile focus area plus upgradient area (1 + E)

Hamilton West focus area plus upgradient area (2 + F)

Hamilton Heights focus area plus upgradient area (3 + G)

Combined 

surface area 

(acres)

415,673

333,560

25,259

50,703

36,532

Total annual 

precipitation volume 

(acre-feet)

1,462,586

612,310

41,449

174,671

64,750

Average annual 

precipitation 

(inches)

42.22

22.03

19.69

41.34

21.27

and sedimentary deposits on the eastern side of the 

valley (areas C and D in fig. 11) and extends from near 

the Skalkaho Highway in the south to the Ravalli 

County line in the north. East-side sediments and 

bedrock are calculated to receive a total of 612,310 

acre-ft/yr of precipitation, for an average annual rate 

of 1.84 ft (22.03 in.). The almost two-fold difference 

in the quantity of precipitation falling on the western 

as opposed to the eastern sides of the valley is 

probably the most significant factor affecting the 

quantity and quality of ground water in the study area.

The potential recharge source area upgradient 

from and including each of the three focus areas is also 

shown in figure 11. The drainage area, total annual precipitation volume, and average annual precipitation in 

each of the three focus areas is presented in table 1. As 

shown in the table, average annual precipitation in the 

area upgradient from and including the Hamilton West 

area is about twice that of the Eightmile and Hamilton 

Heights area.

The quantity of precipitation falling in an area 

represents the upper limit, or maximum potential for 

natural recharge, not the actual quantity of recharge to 

underlying aquifers. The percentage of the total available water that actually recharges a specific aquifer is 

dependent on many complex and interrelated factors 

whose precise determination is beyond the scope of this 

study. For example, most precipitation in the areas 

shown in table 1 occurs at higher altitudes in the mountainous bedrock parts of the drainage. Water that is not 

lost to evaporation, transpiration by trees and mountain 

vegetation, or sublimation of snow will either flow 

overland to mountain streams or will infiltrate fractures 

in the bedrock. Water that infiltrates bedrock will eventually either flow back into mountain streams or 

recharge basin-fill sediments along the mountain front.

As the mountain streams flow onto the valley floor, 

they commonly lose flow to infiltration into basin-fill 

sediments, thereby recharging basin-fill aquifers. 

Diversion of streamflow for irrigation essentially 

spreads water over a larger area, further increasing 

recharge to the basin-fill aquifers.

Sediments along the east side of the valley are 

also recharged by the diversion of irrigation water from 

surface-water sources outside their natural drainage 

area. The Bitterroot Irrigation District Canal transports 

water to most of the eastern benches from Lake Como, 

which is located about 4 mi northwest of Darby. The 

canal facilitates a net transfer of about 70,000 to 75,000 

acre-ft/yr of water from the west side of the valley to 

the eastern benches (Gary Shatzer, Bitterroot Irrigation 

District, oral commun., 1998). The Bitterroot Irrigation Canal supplies about 7,500 acre-ft/yr of water to 

the eastern upgradient end of the Hamilton Heights 

area (Gary Shatzer, written commun., 1998). The 

Republican and Hedge Ditches supply about 4,400 

acre-ft/yr of water diverted from the Bitterroot River to 

the western downgradient one-third of the Hamilton 

Heights area (Barry Persson, Daly Ditches Irrigation 

District, written commun., 1998).

The largest component of discharge from basinfill aquifers is most likely seepage to streams and 

springs primarily in lower altitude, downgradient 

parts of bench areas and along the flood plain of the 

Bitterroot River. Evapotranspiration from these discharge areas is probably the second largest component 

of discharge during the growing season. Withdrawals 

by wells, primarily domestic, is also a discharge component from basin-fill aquifers, although much of the 

water is returned to aquifers through septic systems.

Water-level contours in the Eightmile area (fig. 

8) display several features pertinent to recharge and

Hydrogeology 19
45°45'

EXPLANATION 

Area of west-side sediments

Bedrock drainage area upgradient 

from west side sediments

Area of east side sediments

Bedrock drainage area upgradient 

from east-side sediments

Drainage area upgradient from 

Eightmile focus area

Drainage area upgradient from 

Hamilton West focus area

Drainage area upgradient from 

Hamilton Heights focus area

Focus area and number

1. Eightmile

2. Hamilton West

3. Hamilton Heights

0 5 10 15 KILOMETERS

U.S. Geological Survey digital data, 1:100,000, 1983. Albers Equal Area

Conic Projection Standard parallels 44°00', and 48°00', central meridian -114°00'.

Figure 11. Location of sediments, focus areas, and drainage areas upgradient from sediment and focus areas. 

20 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
discharge in that area. The downgradient bulge 

(convex westward) in the 3,250, 3,275, and 3,300 ft 

contours near Eightmile Creek indicates that the creek 

is losing water to the underlying aquifer and thereby 

creating a ground-water mound in that area. Also, the 

orientation of the water-level contours near the 

northern and eastern boundaries of the area indicate a 

direction of ground-water flow from the hills north and 

east of the area toward the southwest, thereby 

providing subsurface recharge to the alluvial-fan 

deposits underlying the Eightmile area. Lastly, the 

altitude of water levels in the northeast part of the area, 

where shallow water-yielding zones are absent (fig. 8) 

and wells are completed in a deep, confined aquifer, 

are on average more than 100 ft deeper than water 

levels in nearby wells completed in the shallower 

aquifer. The water-level altitude in these deep wells is 

nearly the same as the altitude of the Bitterroot River 2 

miles to the west indicating that the direction of 

ground-water flow in the deep aquifer may not be to 

the west as it is in the shallower aquifer. This study 

could not determine from the available data whether 

the deep aquifer is actually a discontinuous gravel lens 

that does not discharge to the Bitterroot River or 

represents a gravel layer that extends under the hills 

north of the Eightmile area and allows ground water to 

flow to the northwest and eventually discharge to the 

Bitterroot River north and downgradient from the 

study area.

Water-level contours in the Hamilton West area 

are strongly affected by topography (fig. 9). The three 

major streams-Mill Creek, Blodgett Creek, and Canyon Creek-are all deeply incised into the basin-fill 

deposits as they emanate from the mountain front. 

Water-level contours indicate a general direction of 

ground-water flow from the mountain front eastward 

toward the Bitterroot River. Locally the direction of 

ground-water flow is toward the incised streams, indicating that these streams do not directly recharge the 

adjacent alluvial-fan deposits. The alluvial-fan deposits are most likely recharged by smaller streams emanating from the mountain front, flow from the major 

streams diverted for irrigation, subsurface inflow from 

the mountain bedrock, and precipitation and snowmelt 

directly on the fan deposits.

Water-level contours in the Hamilton Heights 

area are also strongly affected by topography (fig. 10). 

The contours indicate a general direction of groundwater flow from the high benches along the mountain

front westward toward the Bitterroot River. Locally the 

direction of ground-water flow is toward the incised 

channels of Coalpit, Willow, and Cow Creeks, indicating that these streams do not directly recharge the nearsurface Tertiary sediments underlying the benches. 

Recharge to the benches is most likely from irrigation 

water derived from the Bitterroot Irrigation District 

Canal and the Republican and Hedge Ditches, and from 

subsurface inflow from the mountain bedrock. 

Although snowmelt on the benches may at times contribute a minor amount of recharge, precipitation during the growing season is probably insufficient to 

exceed evapotranspiration and the soil-moisture deficit.

Ground-Water Quality

Water samples were collected from 240 wells in 

the study area for onsite determination of specific conductance and temperature (table 4 in the Supplemental 

Data section at the back of this report). Water samples 

also were collected from 239 wells (fig. 5) in accordance with guidelines described by Knapton (1985) 

and analyzed in the laboratory for sulfate, chloride, and 

nitrate concentration. Of these wells, 63 were in the 

Eightmile area, 60 were in the Hamilton West area, 51 

were in the Hamilton Heights area, and the remaining 

65 were distributed in other parts of the study area. 

Results of these analyses are presented in table 6 in the 

Supplemental Data section at the back of this report. 

Values and statistics presented in the remainder of this 

section pertain to the samples collected during this 

study and do not include data in table 6 that were collected by MBMG or previous USGS investigations.

Specific conductance is a measure of the ability 

of water to transmit an electric current, which is related 

to the concentration and electrical charge of ions 

present in the water. In natural waters, specific conductance typically is proportional to the dissolved-solids 

concentration of the water-the larger the dissolved-solids concentration, the larger the specific conductance. 

The median ratio of specific conductance to dissolvedsolids concentration for 62 analyses in table 6 is 1.5:1. 

The distribution of specific-conductance values for 

ground water in various locations in the study area is 

shown in figure 12. The median specific-conductance 

value for water from all 240 wells measured was 246 

jj,S/cm. The highest specific-conductance value measured in the study area was 864 ja,S/cm; 54 samples had

Hydrogeology 21
1,000

800

600

400

200

(240) (141)

(85) 

I

(51)

(61)

STUDY AREA 

GEOLOGIC UNITS

WEST-SIDE 

SEDIMENTS

EAST-SIDE 

SEDIMENTS

HAMILTON WEST HAMILTON HEIGHTS 

AREA AREA

EIGHTMILE 

AREA

1,000

- 800

tif O

600

400

200

(24) (8)

(36)

(18)

(87)

Qaf Taf

WEST-SIDE SEDIMENTS

Tabr Qaf Taf 

EAST-SIDE SEDIMENTS

Tabr

EXPLANATION

(24) Number of observations

 Outlier data value less than or equal to 3 

and more than 1.5 times the 

interquartile range outside the quartile

- - Data value less than or equal to 1.5 times the 

interquartile range outside the quartile

- - 75th percentile

---- Median

- - - 25th percentile

- Data value more than or equal to 1.5 times the 

interquartile range outside the quartile

GEOLOGIC UNIT

Oaf-Quaternary alluvial-fan deposits 

Taf~Tertiary alluvial-fan deposits 

Tabr-Tertiary ancestral Bitterroot River deposits

Figure 12. Specific conductance in well water grouped by location and geologic unit. 

22 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
specific-conductance values less than 100 jiS/cm. The 

median specific-conductance value obtained from 

water samples from the 85 wells completed in westside sediments was 90 jiS/cm and from the 141 wells 

completed in east-side sediments was 347 jiS/cm. 

Thus, the median specific-conductance value for water 

from wells completed in east-side sediments was 

almost 4 tunes the median value for west-side 

sediments.

The difference in the median specific-conductance values between west-side and east-side sediments 

is also reflected in the three focus areas (fig. 12). The 

median specific-conductance value obtained from 

water in 61 wells in the Hamilton West area was 87 

jlS/cm--almost identical to the median specific-conductance value obtained from water in all wells completed in west-side sediments. In contrast, the median 

specific-conductance values obtained from water in 51 

wells in the Hamilton Heights area and 61 wells in the 

Eightmile area both of which are located on east-side 

sediments-were 453 and 286 jlS/cm, respectively.

The range of specific-conductance values for 

water samples from wells completed in selected geologic units in the study area is also shown in figure 12. 

The limited number of measurements from water in 

wells completed in Quaternary alluvium and terraces 

(3), Quaternary glacial till (1), and Tertiary through 

Middle Proterozoic bedrock (5) are too small to be statistically significant and are not shown. As shown in 

figure 12, the specific conductance of ground water is 

more dependent on which side of the valley the well is 

located than on the geologic unit in which the well is 

completed. When each side of the valley is considered 

separately, the median specific-conductance value for 

water from wells completed in Tertiary alluvial-fan 

deposits is slightly larger than the median specificconductance values obtained from water in wells completed in the other two geologic units. The slightly 

larger specific-conductance values for Tertiary alluvial-fan deposits could be the result of the geochemical 

characteristics of the sediments, but more probably is 

due to the smaller permeability of that unit, which 

thereby limits recharge and its diluting effects. Likewise, the difference in median specific-conductance 

concentration in water from wells completed in Tertiary alluvial-fan deposits on the east versus the west 

side of the valley could in part be due to the different 

geochemical characteristics of the source rock for the 

sediments but more probably is due to the more limited

quantity of precipitation and therefore recharge available on the east versus the west side of the valley.

The concentration of nitrate can be used as an 

indicator of the effects of human activities on water 

quality. Except in rare instances, nitrate is not available 

as a soluble compound in rocks and minerals. Nitrate 

concentrations in natural waters typically are less than 

2 mg/L (Mueller and others, 1995). Nitrate concentrations that exceed background levels commonly are due 

to human activities such as sewage disposal and fertilizer application.

Large concentrations of nitrate in ground water 

are cause for concern. Studies have shown that infants 

can be seriously harmed, sometimes fatally, by continual ingestion of water containing more than 10 mg/L 

of nitrate, expressed as elemental nitrogen (National 

Academy of Sciences and National Academy of Engineering, 1974). The U.S. Environmental Protection 

Agency (1996) Primary Drinking-Water Regulations 

specify a Maximum Contaminant Level (MCL) of 10 

mg/L for nitrate (as nitrogen) in public drinking-water 

supplies. Large concentrations of nitrate also can be 

indicative of other undesirable contaminants, which 

may include fertilizers, pesticides, or pathogenic bacteria and viruses from sewage.

The median nitrate concentration for the 239 

wells sampled during this study was 0.63 mg/L (fig. 

13). Water from 20 wells sampled during this study 

had nitrate concentrations exceeding 3 mg/L. The largest nitrate concentration sampled in the study area was 

5.9 mg/L; 57 samples had nitrate concentrations below 

the minimum reporting level of 0.15 mg/L. The 

median nitrate concentration for samples collected 

from the 83 wells completed in west-side sediments 

was 0.17 mg/L. The median nitrate concentration for 

samples collected from the 143 wells completed in 

east-side sediments was 1.05 mg/L~or about 6 times 

larger than the median for west-side sediments.

The difference in the median nitrate concentration between west-side and east-side sediments is also 

reflected in the three focus areas. The median nitrate 

concentration for samples collected from 60 wells 

completed in west-side sediments of the Hamilton 

West area was identical to the median for all samples 

collected on the west side of the valley, 0.17 mg/L. In 

contrast, the median nitrate concentrations for 51 wells 

sampled in the Hamilton Heights area and 63 wells 

sampled in the Eightmile area-both areas containing

Hydrogeology 23
(239) 

o 

o

(83) 

o

(60) 

o

(51)

(63)

1 °

2 STUDY AREA

- GEOLOGIC UNITS 

g

WEST-SIDE 

SEDIMENTS

EAST-SIDE 

SEDIMENTS

HAMILTON WEST HAMILTON HEIGHTS 

AREA AREA

EIGHTMILE 

AREA

(24)

(51) 

O

(36) 

o

(89)

(18)

Qaf Taf 

WEST-SIDE SEDIMENTS

Tabr Qaf Taf 

EAST-SIDE SEDIMENTS

Tabr

EXPLANATION

(24) 

o

Number of observations

Outlier data value more than 3 times the 

interquartile range outside the quartile

Outlier data value less than or equal to 3 

and more than 1.5 times the 

interquartile range outside the quartile

 Data value less than or equal to 1.5 times the 

interquartile range outside the quartile

75th percentile

Median

25th percentile

Data value more than or equal to 1.5 times the 

interquartile range outside the quartile

Minimum reporting level

GEOLOGIC UNIT

Oaf-Quaternary alluvial-fan deposits 

Taf-Tertiary alluvial-fan deposits 

Tabr-Tertiary ancestral Bitterroot River deposits

Figure 13. Nitrate concentration in well water grouped by location and geologic unit.

24 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
east-side sediments were 1.40 and 0.91 mg/L, 

respectively.

The range of nitrate concentrations in water from 

wells completed in selected geologic units in the study 

area is also shown in figure 13. As with specific conductance, the concentration of nitrate in ground water 

is more dependent on which side of the valley the well 

is located than on the geologic unit in which the well is 

completed. Also similar to the distribution of specific 

conductance, the median nitrate concentration for samples from wells completed in Tertiary alluvial-fan 

deposits is slightly larger than the median for the other 

two geologic units when each side of the valley is considered separately. The slightly larger nitrate concentrations in Tertiary alluvial-fan deposits is most likely 

also due to the lower permeability of that unit, which 

limits the diluting effects of recharge on nitrate concentration.

The relation between nitrate concentration and 

shallowest well open interval is presented in figure 14. 

Data for 43 wells that lack depth information are not

shown. The percentage of wells with nitrate concentrations exceeding 3 mg/L~fifty percent greater than the 

assumed background concentration for the area was 

5.6 for all 195 wells, 8.0 for the 144 wells with depth to 

top of open interval less than 125 feet, and 16.2 for the 

37 wells with depth to top of open interval less than 40 

feet.

The occurrence of larger nitrate concentrations at 

shallower well depths is probably best understood by 

the fact that nitrate enters the ground-water system primarily from surface sources and slowly moves deeper 

into the aquifer if the vertical component of the hydraulic gradient is downward. Nitrate can be removed from 

an aquifer through the process of denitrification, which 

involves microbial conversion of nitrate to nitrogen gas 

in reducing (anoxic) environments a condition more 

common in deeper parts of an aquifer. However, data 

are insufficient to determine the extent of denitrification in the study area. The general relation between 

nitrate concentration and well depth does not seem to 

be dependent on sample location in the valley.

50

100

150

200

250

300 S 

o 

o

2 350 (0

S

400

450

500

550

n 

@ AQ^D p *n

- *i D ° - ann

DA D

~n LJ " n fiA

«P .n n A D

A n D .

.o A D nS *

n

-o

DD

3 MILLIGRAM PER LITER 

REFERENCE

EXPLANATION 

A EIGHTMILE AREA 

0 HAMILTON WEST AREA 

D HAMILTON HEIGHTS AREA 

 OUTSIDE OF FOCUS AREAS

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 

NITRATE CONCENTRATION AS N, IN MILLIGRAMS PER LITER

6.0

Figure 14. Nitrate concentration in well water versus depth to top of well casing open interval.

Hydrogeology 25
The distribution of nitrate concentrations in 

water from wells in each of the three focus areas is 

shown in figures 15-17. To determine the timing and 

magnitude of any seasonal fluctuation in the concentration of nitrate in ground water, 16 wells were sampled 

approximately bimonthly from November 1996 

through October 1997. The changes in nitrate concentration of samples from the 15 wells located in the three 

focus areas are shown in figure 18. Of the three areas, 

samples from the five wells in the Eightmile area show 

the clearest pattern of nitrate concentration fluctuations 

with season; the smallest concentrations occur in AprilJune and the largest in January. Whereas the magnitude of change in nitrate concentration in the Hamilton 

West and Hamilton Heights areas can be as large as in 

the Eightmile area, samples from the five wells in each 

of the Hamilton West and Hamilton Heights areas do 

not show the same pattern as in the Eightmile area.

The precise cause of the seasonal variability in 

nitrate concentration cannot be determined from the 

available data. However, it is important to note the seasonal variability when interpreting the data or attempting long-term trend analysis. The nitrate data 

presented in figures 15-17 are based on samples collected at different times in the 1994,1995, and 1996 

field seasons; therefore, the data contain both seasonal 

variability and spatial differences. For example, on the 

basis of August 1994 samples, water from well 

10N19W07BAAD01 is shown in figure 15 as having a 

nitrate concentration of 3.2 mg/L, which is noticeably 

larger than the nitrate concentrations shown for nearby 

wells. When the well was resampled in August, 3 years 

later, the water had a similar nitrate concentration of 

3.1 mg/L. However, when the well was sampled in 

April 1997, the nitrate concentration was 1.9 mg/L. If 

the data presented for well 10N19W07BAAD01 in figure 15 had by chance been based on an April rather than 

August sample, the relation of nitrate concentration in 

nearby wells would probably have been different from 

that shown.

In addition to the variability caused by actual 

environmental conditions, uncertainty is introduced 

during the course of sample collection and laboratory 

analysis. In an attempt to assess the degree to which 

these uncertainties are present in the data, 48 blind replicate samples were collected and submitted concurrently from the field along with 391 separate samples 

collected from the 239 wells. Results are included in 

table 6. An additional replicate sample listed in table 6

(07N21W13BBAD01) was from a previous study 

which did not include nitrate. The median difference in 

nitrate concentration between replicates of 48 samples 

was 0.01 mg/L. The 5 largest differences in nitrate concentration between replicates were 1.0, 0.9, 0.5,0.5, 

and 0.4 mg/L, and 23 replicates had no difference (0.0 

mg/L). The median difference for the 48 replicates was 

2 percent, and 33 replicates (68 percent of the total) had 

a 10 percent or smaller difference.

The use of these data in the interpretation of 

long-term trends should proceed only with a full understanding of the temporal variability and procedural 

uncertainty presented above. Any attempts at longterm trend analysis of nitrate concentration in the study 

area should be based on an extensively quality-assured 

dataset of sufficient temporal and spatial continuity to 

allow for a statistically significant separation of analytical and seasonal variability from long-term trends in 

the data.

Additional water samples were collected from 43 

wells, 3 streams, 1 irrigation canal, and 1 spring for laboratory analysis of major-ion and trace-element concentrations. Water samples from the 43 wells were also 

analyzed for radon concentration. The locations of surface-water sites and the one spring are listed in table 2. 

Major-ion and trace-element concentrations in water 

samples collected during this and previous studies are 

presented in tables 6-9 in the Supplemental Data section at the back of this report. The dominant cations 

and anions in samples from the three focus areas are 

graphically summarized in figure 19. On the basis of 

the data presented, water from wells in all three focus 

areas is primarily a calcium bicarbonate type. However, water in the Hamilton West and Hamilton Heights 

areas tends to have a slightly larger percentage of 

sodium than does water in the Eightmile area, with one 

sample in the Hamilton West area and two samples in 

the Hamilton Heights area being classified as sodium 

bicarbonate type.

The suitability of water for public drinking-water 

supply is established by the U.S. Environmental Protection Agency Primary and Secondary DrinkingWater Regulations (table 12). National Primary Drinking-Water Regulations are established for contaminants which, if present in drinking water, may cause 

adverse human health effects. Either an MCL or a treatment technique is specified by these regulations for 

regulated contaminants. MCL's are health based and

26 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
114°02'30

46°38'30" -

T. 10 N

46°37'30

R. 20 W. R. 19 W.

Base from U.S. Geological Survey digital data, 1:24,000, 1979 to present. 

Albers Equal Area Conic Projection Standard parallels 44°00', and 48°00', 

central meridian -114° 00'.

0.25 0.5 0.75 1 MILE

0 0.25 0.5 0.75 1 KILOMETER

EXPLANATION 

INVENTORIED WELL

 Well in water-level

monitoring network

? Well in water-level and 

nitrate monitoring 

networks

o Well not in monitoring 

network

0.75 NITRATE CONCENTRATION, 

IN MILLIGRAMS PER LITER; 

-, no data; br, below minimum 

reporting level

Figure 15. Distribution of nitrate concentration in well water from the Eightmile area, 1994-96.

FIGURE 15 27

114°12'30"

TO" 3 

5.

r

46°17'30

46°15

r

3- 

o

ffi

Base from U.S. Geological Survey digital data, 1:24,000, 1979 to present. 

Albers Equal Area Conic Projection Standard parallels 44°00', and 48°00', 

central meridian -114° 00'

0.25 0.5 0.75 1 MILE

EXPLANATION 

INVENTORIED WELL

 Well in water-level

monitoring network

X Well in water-level and 

nitrate monitoring 

networks

o Well not in monitoring 

network

0.75 NITRATE CONCENTRATION, 

IN MILLIGRAMS PER LITER; 

-, no data; br, below minimum 

reporting level

\ r

0 0.25 0.5 0.75 1 KILOMETER

114°05' 114°02'30" R. 20 W. R. 19 W.

46°18'30" 

46°17'30" -

EXPLANATION

INVENTORIED WELL

 Well in water-level

monitoring network

X Well in water-level and 

nitrate monitoring 

networks

o Well not in monitoring 

network

0.75 NITRATE CONCENTRATION, 

IN MILLIGRAMS PER LITER; 

-, no data; br, below minimum 

reporting level

Base from U.S. Geological Survey digital data, 1:24,000, 1979 to present. 

Albers Equal Area Conic Projection Standard parallels 44''00', and 48°00', 

central meridian -114° 00'.

0 0.25 0.5 0.75 1 MILE

0 0.25 0.5 0.75 1 KILOMETER

Figure 17. Distribution of nitrate concentration in well water from the Hamilton Heights area, 1994-96.

FIGURE 17 29
oc

UJ 5 5

oc

LU 

Q. 

(0

UJ §'

o

LUi o

EXPLANATION

EIGHTMILE AREA 

4 10N20W12DADA01 

O- 10N19W08ABBC01 

D 10N19W08CBDD01 

 10N19W08DCCB01 

He- 10N19W07BAAD01

HAMILTON WEST AREA

-A 06N21W02ABBD01

-O- 06N21W03CAAC01

-O 06N21W13BBAB01

- 06N21W24CCAC01

-* 06N21W27ADBC01

HAMILTON HEIGHTS AREA

-A 06N20W01CDCD01

-O 06N20W04ADCD01

-O 06N20W04DCCB01

- 06N20W10AADC01 

^ 06N20W12CCCD01

NDJFMAMJJASO 

1996 1997

Figure 18. Monthly variation in nitrate concentration in well water.

30 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
EXPLANATION

FOCUS AREA 

A Eightmile area 

+ Hamilton West area 

X Hamilton Heights area

WATER TYPE

I Calcium bicarbonate

II Calcium sulfate 

Hi Sodium sulfate 

IV Sodium bicarbonate

Figure 19. Modified trilinear diagram showing percentages of major ions in well water from the three focus areas. Data were converted 

from milligrams per liter to millequivalents per liter, then values for each cation and anion were plotted on the diagram as a percentage of 

total milliequivalents per liter.

FIGURE 19 31
Table 2. Location and description of surface-water sites and one spring (shown in downvalley order)

Location number Site description

06N21W20AABB01 

06N20W12AACD01 

06N20W12AACD02 

08N20W02ACBD01 

10N19W03DCCD01

Blodgett Creek on west side of Blodgett Canyon Campground Bridge, about 5 miles west of Hamilton 

Bitterroot Irrigation District Canal where it crosses Willow Creek, about 5 miles southeast of Corvallis 

Willow Creek east of where the Bitterroot Irrigation District Canal crosses, about 5 miles southeast of Corvallis 

Spring at 373 Pine Hollow Road, about 2 miles southeast of Stevensville 

Eightmile Creek where Granite Creek Road crosses on northeast side, about 6 miles east of Florence

enforceable (U.S. Environmental Protection Agency, 

1996). National Secondary Drinking-Water 

Regulations are established for contaminants that can 

adversely affect the odor or appearance of water and 

result in discontinuation of use of the water. These 

regulations specify Secondary Maximum Contaminant 

Levels (SMCLs) that are esthetically based and 

nonenforceable (U.S. Environmental Protection 

Agency, 1996).

The major-ion and trace-element concentrations 

shown in tables 6-9 are all less than the MCL's except 

for one occurrence of cadmium equal to the MCL of 5 

|Llg/L. One sample has a fluoride concentration larger 

than the SMCL of 2 |Llg/L, six samples have iron concentrations larger than the SMCL of 300 |Ug/L, and five 

samples have manganese concentrations larger than the 

SMCLof50|Llg/L.

In an attempt to assess the degree of uncertainty 

in the major-ion, trace-element, and radon data due to 

sample collection and laboratory analysis, five blind 

replicate samples and two field blanks were processed 

and submitted concurrently from the field. Results of 

the replicate analyses are included in tables 6 and 7. 

Agreement between constituent concentrations in replicate samples generally was good, with several exceptions: one instance of a 13-percent difference in 

chloride concentration, one instance of a 25-percent 

difference in potassium concentration, and one 

instance of a 58-percent difference in iron concentration and 3 3-percent difference in manganese concentration at magnitudes near the minimum reporting 

levels for these constituents. Results of the field-blank 

analyses are shown in tables 10 and 11 in the Supplemental Data section at the back of this report. All analyzed constituents in field blanks were below the 

minimum reporting level, except for one instance of 

potassium concentration at 0.19 mg/L and silica concentrations of 20 mg/L in two blanks. The silica present 

in the blank samples has been recognized previously as

being due to contamination by the deionizing filters 

used to prepare the blank in the laboratory. Silica contamination of well-water samples due to sample preparation is probably minimal and was not of concern for 

this study.

Radon is a naturally occurring, odorless, tasteless, inert gas formed by the natural radioactive decay 

of uranium, which is present to some extent in nearly 

all rocks. Granitic rocks such as those surrounding 

much of the Bitterroot Valley commonly contain uranium. The presence of radon is a cause for concern 

because inhalation of its radioactive decay products at 

sufficiently elevated concentrations is known to cause 

lung cancer. The average overall world indoor radon 

concentration in air is about 0.4 pCi/L. However, indications are that average concentrations in the United 

States are higher (Cothern, 1987). To minimize exposure and possible health risks, the U.S. Environmental 

Protection Agency (1992) recommends that the average radon concentration in indoor air not exceed 4.0 

pCi/L.

The primary source of radon in indoor air is the 

soil; radon from the soil can infiltrate houses through 

cracks, vents, joints, or other openings in basement 

floors and walls. The next largest source of radon in 

indoor air is from degassing from well water used for 

household purposes. A radon concentration of 10,000 

pCi/L in water is estimated to produce a 1 pCi/L 

increase in radon concentration in air, given the typical 

usage and household characteristics in the United 

States (Cothern, 1987). To keep radon concentrations 

in indoor air to a minimum, the U.S. Environmental 

Protection Agency (1996) established an MCL for 

radon in water of 300 pCi/L but subsequently withdrew 

the regulation in July 1997 at the direction of the U.S. 

Congress (U.S. Environmental Protection Agency, 

1997). Congress has directed the U.S. Environmental 

Protection Agency to propose new regulations for

32 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
radon-222 by August 1999 and promulgate a final regulation by August 2000.

The 43 radon concentrations shown in table 7 

range from 150 to 3,700 pCi/L and have a median of 

810 pCi/L. By focus area, the median radon concentration was 710 pCi/L for 15 samples in the Eightmile 

area, was 1,205 pCi/L for 10 samples in the Hamilton 

West area, and was 215 pCi/L for 8 samples in the 

Hamilton Heights area. Effective treatments for the 

removal of radon from ground water are available (U.S. 

Environmental Protection Agency, 1992).

AQUIFER SENSITIVITY

Water contamination can include any chemical, 

physical, or biological constituent, compound, or characteristic that is considered to be undesirable for an 

intended use of the water. Dissolved contaminants generally are transported in the direction of ground-water 

flow, although some transport can occur by diffusion. 

However, contaminants that do not dissolve in water 

can move in directions that differ from the direction of 

ground-water flow, although some transport can occur 

by diffusion. For example, compounds that are more 

dense than water can move downward through the 

aquifer, even in areas where the vertical component of 

hydraulic gradient and vertical component of flow are 

upward. Compounds that are less dense than water can 

mound on the water table and move in directions other 

than the direction of ground-water flow. The contaminants considered in this study generally are dissolved 

chemical constituents or compounds.

Aquifers in many parts of the study area are relatively susceptible to potential contamination from surface or near-surface sources because the coarse-grained 

character of the near-surface sediments could allow 

contaminants to readily infiltrate. In these areas, the 

underlying aquifers are commonly unconfined and can 

be contaminated by septic-system overflow or failure, 

fuel from surface spills or leaking underground storage 

tanks and pipe lines, leachate from landfills and sewage 

lagoons, agricultural and residential chemicals, and 

other sources of inorganic and organic compounds. For 

example, part of the alluvial aquifer in the northern part 

of the study area has been affected by leachate from a 

landfill, resulting in contamination of water in the area 

of several downgradient wells (Ravalli County Sanitarian's Office, written commun., 1998). Other potential 

sources of contamination include urban storm-water

runoff, effluent from municipal waste water disposal, 

and dry sumps. Most of the documented and potential 

sources of contamination to the aquifers are point specific and affect only relatively localized areas. This 

study focused on characterizing the overall water quality in the Bitterroot Valley and did not address known 

point-source water-quality problems.

Rapid and continued population growth and the 

resulting widespread residential development probably 

represent the greatest potential for change to water 

quality in the study area. As shown in figure 20, population growth in Ravalli County has been greatest since 

1990, and most of this growth has occurred within the 

rural parts of the study area. The nitrate concentration 

data collected by this study can, with certain limitations, serve as a surrogate to measure human effects on 

the aquifers underlying the study area.

Although rural septic input, residential fertilizers, and domestic animal waste can all contribute to 

nitrate loading of an aquifer and may be expected to 

increase with increased rural population, most of the 

study area currently undergoing new residential development was previously used for agriculture. Agricultural activity also can be a source of nitrate loading, 

primarily from inorganic fertilizers and animal manure. 

Therefore, the nitrate-concentration data presented in 

this report probably reflect nitrate loading from multiple sources. Analytical techniques using nitrogen isotopes can potentially differentiate between animal 

waste which includes septic effluent and inorganic 

fertilizer sources but employment of those analytical 

techniques was beyond the resources available for this 

study.

Although the dominant source of nitrate loading 

cannot be uniquely identified at most sample sites, the 

relatively small nitrate concentrations in the 239 wells 

sampled for this study indicate that the total nitrate load 

to the sampled aquifers has not resulted in nitrate concentrations that exceed the U.S. Environmental Protection Agency (1996) MCL to date. Localized areas of 

some aquifers might have nitrate concentrations larger 

than those reported in this study, but no areas were 

identified from the data.

Two qualifications are worth noting with respect 

to the relation between the relatively small nitrate concentrations presented in this report and the potential 

water-quality effects resulting from increased populaAquifer sensitivity 33
35,000

30,000 -

25,000 -

20,000 -

15,000 -

10,000

YEAR

Figure 20. Population of Ravalli County by year, 1970-97. Numbers are estimates, except for 1970, 1980, and 1990, which are from the 

decennial census. Data from U.S. Bureau of the Census (issued annually; issued decennially).

tion and development in the study area. Whereas the 

nitrate data do not indicate any widespread problems 

at the time the samples were collected, the lag between 

the time when a change in land use causes a change in 

nitrate loading to an area and the time when any 

resulting change in nitrate concentration can be 

detected at a downgradient sample site cannot be 

determined from the available data. Given this 

uncertainty, the samples collected during this study 

might be the result of the nitrate loading patterns 

dominant many years prior to sample collection. If this 

were true, changes in nitrate loading patterns due to 

present land use changes might not be detectable in 

samples until some time in the future.

The second qualification is that the response of 

the aquifers to nitrate loading, as measured by nitrate 

concentration in well water, is not necessarily directly 

proportional to the total nitrate load to the aquifer. As a 

hypothetical example, if nitrogen uptake by plants in a 

shallow ground-water area just downgradient from a 

small residential subdivision using septic systems is 

capable of removing just enough nitrate to maintain a 

concentration in ground water of 0.5 mg/L, doubling 

the size of the subdivision and the resulting nitrate load 

could potentially more than double the downgradient 

nitrate concentration if the capacity of the plants to 

remove nitrate were exceeded by the additional loading. A "threshold effect" similar to the one described 

could apply to other chemical constituents and buffering mechanisms as well.

Although the specific conductance and nitrate 

concentrations in ground water sampled in the study 

area were generally small, differences were significant 

between different parts of the study area, which is pertinent to the sensitivity of the aquifers in those areas to 

contamination. The Hamilton West area had the smallest median values for specific conductance and nitrate 

concentration of the three focus areas even though it 

had the largest population, and presumably septic-tank 

density, indicated by the density of wells (table 3). 

Conversely, the Hamilton Heights area had the largest 

median values for specific conductance and nitrate 

concentration and the smallest population density indicated by the density of wells. Specific conductance and 

nitrate concentration in the Eightmile area fell in 

between these two extremes.

The sensitivity of the focus-area aquifers to 

nitrate loading is most strongly related to the total 

ground-water recharge to each area-the greater the 

recharge (and hence dilution), the less sensitive is the 

aquifer (as measured by nitrate concentration in water 

from wells) to a given nitrate load. The quantity of 

ground-water recharge in the three areas is primarily 

controlled by two factors the average annual precipi34 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 3. Summary of specific conductance, nitrate concentration, well density, average precipitation, and percentage of wells 

completed in Tertiary alluvial-fan deposits in the three focus areas. Table ordered by increasing values of specific conductance and 

nitrate concentration

[Abbreviations: uS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L, milligrams per liter]

Focus area

Hamilton West 

Eightmile 

Hamilton Heights

Median specific 

conductance in 

(uS/cm)

87 

286 

453

Median nitrate 

concentration 

(mg/L)

0.17 

.91 

1.40

Average number 

of wells per square 

mile

62 

51 

31

Average 

precipitation 

(inches)

41.28 

19.68 

21.24

Percentage of 

sampled wells 

completed in 

Tertiary alluvialfan deposits

6.3 

0 

43.3

tation and, to a lesser degree, the percentage of 

Tertiary alluvial-fan deposits in the respective area.

The difference in average annual precipitation in 

and upgradient of the three areas and the resulting 

quantity of water available for recharge is most probably the cause of the substantially smaller values for specific conductance and nitrate concentration in the 

Hamilton West area as compared to the Eightmile and 

Hamilton Heights areas (table 3). The drainage area of 

the Hamilton West area receives about twice the annual 

precipitation of the other two focus areas. Thus, the 

larger quantity of water available for recharge in the 

Hamilton West area probably has a diluting effect on 

the specific conductance and nitrate concentration.

The extensive Tertiary alluvial-fan deposits in 

the Hamilton Heights area are probably the cause of the 

larger specific conductance and nitrate concentrations 

as compared to the Eightmile area (table 3). Because 

the Tertiary alluvial-fan deposits are generally less permeable, recharge to the Hamilton Heights area is more 

limited than in the Eightmile area. The smaller quantity 

of recharge to the Tertiary alluvial-fan deposits limits 

dilution in those areas.

Although aquifers in west-side sediments have 

smaller values for specific conductance and nitrate 

concentration than those on the east side of the valley, 

the west-side sediments might contribute more constituent loading to the Bitterroot River than the east-side 

sediments. The total constituent load to a system is a 

function of the concentration of a constituent in the 

source water multiplied by the total volume of that 

water that recharges the system. Even though constituent concentrations in ground water on the west side of

the valley are generally much smaller than those on the 

east side, data presented in this report indicate that the 

rate of ground-water flow through the west-side sediments and eventually discharging to the Bitterroot 

River is considerably larger than that of the east side. 

However, data of sufficient precision to accurately 

determine the extent of loading in the study area are not 

available.

SUMMARY AND CONCLUSIONS

The Bitterroot Valley is located in Ravalli 

County of western Montana. During the early 1990s, 

the Ravalli County estimated population increased at 

the fastest rate in the State, with much of the increase 

occurring outside of established cities and towns. The 

potential for degradation of local aquifers due to continued growth is large. This study was initiated to 

establish a ground-water monitoring network, implement a geographically indexed computer-based data 

framework, define ground-water flow paths, describe 

ground-water recharge sources and discharge areas, 

characterize any potential sources of ground-water 

degradation, and identify any areas with existing degradation.

The Bitterroot Valley is situated in a 7-mi wide 

by 5 2-mi long north-trending intermontane basin in the 

Northern Rocky Mountains physiographic province. 

The Bitterroot Valley contains two principal topographic features and related aquifers-the flood plain of 

the Bitterroot River, which extends the length of the 

valley, and the adjacent extensive high benches along 

the east and west sides of the valley.

Summary and conclusions 35
The major surface-water artery of the Bitterroot 

Valley is the Bitterroot River, which originates in the 

southern Bitterroot Mountains and the Anaconda 

Range and flows northward through the basin to its 

confluence with the Clark Fork about 15 mi north of the 

study area. About 4 times as many tributaries join the 

river from the Bitterroot Mountains on the west as from 

the drier Sapphire Mountains on the east.

To provide a more in-depth investigation of 

selected areas of the valley, three focus areas were 

selected on the basis of physiography, geology, climate, 

effect of irrigation, and development pressure. The 

three areas are referred to as the Eightmile, Hamilton 

West, and Hamilton Heights areas.

The Bitterroot Valley is situated in a structural 

basin most probably formed by crustal extension during the middle Eocene Epoch. Intrusive, metasedimentary, metamorphic, and volcanic rocks border the 

valley and Tertiary sediments overlie bedrock and crop 

out on the eastern, and to a lesser extent, western 

benches. Tertiary sediments also occur at depth 

beneath the benches, beneath a veneer of Quaternary 

alluvium along the Bitterroot River flood plain, and 

beneath Quaternary alluvial fans along the floors of 

tributary valleys. These unconsolidated to semiconsolidated Tertiary deposits are composed of gravel, sand, 

silt, and clay that occur as two distinct geological units: 

the ancestral Bitterroot River deposits and the Sixmile 

Creek Formation.

The ancestral Bitterroot River deposits the 

lower of the two Tertiary units in the basin are composed of rocks derived from the entire drainage basin, 

with several distinctive clast types indicating transport 

from the far southwestern end of the basin and possibly 

even beyond. The ancestral Bitterroot River deposits 

most likely result from deposition by a northward 

through-flowing river of regional scale during the middle Eocene to middle Miocene epochs. The Sixmile 

Creek Formation overlies the ancestral Bitterroot River 

deposits and is composed of locally derived, poorly 

sorted erosional debris of the adjacent mountains.

Quaternary glacial till underlies many of the high 

benches along the Bitterroot Mountains, especially in 

the southern part of the study area west of Darby. Quaternary alluvial-fan deposits are present along much of 

the western side of the valley and along the larger tributary streams on the eastern side of the valley. Quaternary alluvium and terrace deposits occur along the

present flood plain of the Bitterroot River. The configuration of the water-level surface in the three focus 

areas was determined from water levels measured from 

August through December 1995.

Most wells in the Bitterroot Valley are completed 

in unconfined to semiconfined aquifers contained in 

basin-fill deposits of Quaternary and Tertiary age. 

These deposits can best be described as a sequence of 

complexly stratified lenses of cobbles, gravel, and sand 

with varying amounts of intercalated silt and clay.

Data for 9,424 wells were combined with the 

geologic map information to produce statistics characterizing the depth to static-water level, yield, and specific capacity of wells completed in various geologic 

units and in various areas of the valley. Wells completed in Quaternary alluvium and terrace deposits had 

the shallowest static-water levels and the largest values 

for yield and specific-capacity. Wells completed in 

Quaternary alluvial-fan deposits had similar staticwater levels but smaller values for yield and specific 

capacity. Wells completed in Tertiary alluvial-fan 

deposits had the deepest static-water levels and smallest yield and specific-capacity values of all basin-fill 

units analyzed. Hydraulic characteristics of the ancestral Bitterroot River deposits are between those of Quaternary deposits and Tertiary alluvial-fan deposits.

Regionally, the direction of ground-water flow 

in the Bitterroot Valley is from the mountain front 

along the basin margins toward the center of the basin 

and diagonally downvalley. The configuration of the 

water-level surface generally reflects topography, with 

steep hydraulic gradients in the recharge areas along 

the mountain front and more gradual gradients in discharge areas along the flood plain of the Bitterroot 

River. The configuration of the water-level surface in 

the three focus areas was determined from water levels 

measured from August through December 1995.

Basin-fill aquifers in the Bitterroot Valley are 

recharged by infiltration of streamflow and irrigation 

water, subsurface inflow from surrounding bedrock, 

and direct infiltration of precipitation and snowmelt. 

The western side of the valley receives about twice as 

much precipitation as the eastern side of the valley, 

which is probably the most significant factor affecting 

the quantity of recharge in those areas. Sediments 

along the east side of the valley are also recharged by 

the diversion of irrigation water from surface-water 

sources outside their natural drainage area.

36 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
The largest component of discharge from basinfill aquifers is most likely seepage to streams and 

springs which occurs primarily in lower altitude, downgradient parts of bench areas and along the flood plain 

of the Bitterroot River. Evapotranspiration is probably 

the second largest component of discharge during the 

growing season. Withdrawals by wells, primarily 

domestic, also discharge basin-fill aquifers, although 

much of the water is returned to the aquifers through 

septic systems.

The median specific-conductance value for 

water from the 240 wells measured in the study area 

was 246 jiS/cm. The largest specific-conductance 

value measured was 864 jiS/cm; 54 wells had specificconductance values less than 100 |o,S/cm. The median 

specific-conductance value obtained from water samples from 141 wells on the east-side sediments of the 

valley was 347 jiS/cm, which was about 4 times as 

large as the median specific-conductance value of 90 

flS/cm obtained from the 85 wells measured on the 

west-side sediments side of the valley. The specific 

conductance of ground water is more dependent on 

which side of the valley the well is located than on the 

geologic unit in which the well is completed.

The median nitrate concentration for the 239 

wells sampled in the study area was 0.63 mg/L. Water 

from 20 wells sampled had nitrate concentrations 

exceeding 3 mg/L. The largest nitrate concentration 

was 5.9 mg/L; 57 samples had nitrate concentrations 

below the minimum reporting level. The median 

nitrate concentration for samples collected from the 

143 wells in the east-side sediments of the valley was 

1.05 mg/L~or about 6 times larger than the median of 

0.17 mg/L for samples from the 83 wells completed in 

west-side sediments. The concentration of nitrate in 

ground water is more dependent on which side of the 

valley the well is located than on the geologic unit in 

which the well is completed. Data for 16 wells sampled 

approximately bimonthly from November 1996 

through October 1997 indicate a significant seasonal 

variability in nitrate concentration in those wells.

On the basis of water samples collected from 43 

wells, ground water in the three focus areas is primarily 

a calcium bicarbonate type. However, one sample in 

the Hamilton West area and two samples in the Hamilton Heights area are a sodium bicarbonate type. All 

constituent concentrations were less than MCL's 

except for one occurrence of cadmium equal to the

MCL of 5 Jig/L. One sample had a fluoride concentration larger than the SMCL of 2 jig/L, six samples had 

iron concentrations larger than the SMCL of 300 Jig/L, 

and five samples had manganese concentrations larger 

than the SMCL of 50 (ig/L. Radon concentrations for 

samples from 43 wells range from 150 to 3,700 pCi/L 

and have a median of 810 pCi/L.

Rapid and continued population growth and the 

resulting widespread residential development probably 

represent the greatest potential for change to water 

quality in the study area. Although the relatively small 

nitrate concentrations in the 239 wells sampled for this 

study indicate that the total nitrate load to the sampled 

aquifers has not resulted in nitrate concentrations that 

exceed recommended standards to date, significant differences exist between different parts of the study area 

which are pertinent to the sensitivity of the aquifers in 

those areas to contamination. The sensitivity of the 

focus-area aquifers to nitrate loading is most strongly 

related to the total ground-water recharge to each 

area the greater the recharge, the less sensitive the 

aquifer is to nitrate loading. The quantity of recharge 

is directly related to the average annual precipitation 

and inversely related to the occurrence of low-permeability surface deposits, such as Tertiary alluvial-fan 

deposits in the area.

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Selected references 39
SUPPLEMENTAL DATA

40 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 4. Records of selected wells

Location number numbering system described in text. 

Altitude of land surface in feet above sea level.

Geologic unit--Qaf, Quaternary alluvial-fan deposits; Qalt, Quaternary alluvium and terrace deposits; Tabr, Tertiary ancestral Bitterroot River deposits; 

Taf, Tertiary alluvial-fan deposits; TYb, Tertiary through Middle Proterozoic bedrock.

Depth of well in feet below land surface.

Casing diameter in inches.

Type of finish O, open end; P, perforated or slotted; S, screen.

Depth to top of open interval in feet below land surface.

Type of log available D, driller.

Primary use of water C, commercial; F, fire; H, domestic; I, irrigation; P, public supply; S, stock; U, unused.

Depth to water in feet below land surface; flowing, water level above land surface.

Yield-in gallons per minute, reported to nearest whole number.

Specific capacity~in gallons per minute per foot of drawdown in a well.

Source of yield data~D, driller; O, owner; R, Reported; S, USGS.

Abbreviations- °C, degrees Celsius; ft, feet; gal/min, gallons per minute; [(gal/min)/ft], gallons per minute per foot; in., inch; (iS/cm, microsiemens per 

centimeter at 25 °C.

Symbols: <, less than; , no data or not applicable.

TABLE 4 41
Table 4. Records of selected wells (Continued)

Location number

10N20W02ABBC01

10N20W10ACBC01

10N20W10CBBD01

10N20W11CDCD01

10N20W12ACDB01

10N20W12ADCB01

10N20W12ADDC01

10N20W12DAAA01

10N20W12DABD01

10N20W12DADA01

10N20W12DDDC01

10N20W13BBA01

10N19W05CCCC01

10N19W05CCCD01

10N19W05CDCC01

10N19W05DCDD01

10N19W06CDCB01

10N19W06CDDA01

10N19W06CDDD01

10N19W06DCCC01

10N19W06DCDA01

10N19W06DDCC01

10N19W07ADBC01

10N19W07BAAD01

10N19W07BACB01

10N19W07BCBB01

10N19W07BDAD01

10N19W07BDBB01

10N19W07CAAB01

10N19W07CABD01

10N19W07CACC01

10N19W07CDAA01

10N19W07CDBA01

10N19W07CDCC01

10N19W07DABB01

10N19W07DBBC01

10N19W07DBDA01

10N19W07DDCD01

10N19W07DDDC01

10N19W08ABBC01

10N19W08ADAD01

10N19W08ADDC01

10N19W08BADD01

10N19W08BBDD01

10N19W08BCAD01

Altitude of 

land 

surface 

(ft)

3,225

3,540

3,555

3,250

3,214

3,226

3,236

3,244

3,226

3,243

3,220

3,204

3,380

3,388

3,399

3,470

3,288

3,306

3,310

3,314

3,340

3,352

3,346

3,306

3,283

3,262

3,306

3,292

3,300

3,282

3,273

3,296

3,282

3,268

3,340

3,310

3,330

3,326

3,334

3,448

3,500

3,490

3,442

3,408

3,402

Geologic 

unit

Qaf

Tabr

Tabr

Tabr

Tabr

Tabr

Qaf

Qaf

Qaf

Tabr

Qaf

Tabr

Qaf

Qaf

Tabr

Qaf

Tabr

Qaf

Tabr

Qaf

Tabr

Tabr

Qaf

Tabr

Tabr

Tabr

Qaf

Tabr

Tabr

Qaf

Tabr

Qaf

Tabr

Tabr

Tabr

Qaf

Tabr

Qaf

Qaf

Tabr

Tabr

Tabr

Qaf

Qaf

Tabr

Depth of 

well 

(ft)

193

50

339

75

90

~

57

__

51

~

-

80

80

109

-

71

135

85

120

75

--

104

73

39

110

~

59

140

120

_.

72

~

~

120

340

287

-

320

Casing 

diameter 

(in.)

6.0

6.0

6.0

6.0

_

«

~

6.0

._

6.0

~

60.0

6.0

6.0

-

6.0

--

6.0

6.0

--

6.0

6.0

6.0

--

6.0

6.0

6.0

6.0

--

6.0

6.0

__

6.0

~

6.0

6.0

6.0

-

6.0

Type of 

finish

-

O

P

P

O

.

-

-

-

O

-

O

-

-

P

-

P

-

P

-

P

s

-

O

O

O

-

P

P

O

P

-

P

-

P

-

s

-

-

P

P

s

-

-

P

Depth to 

top 

of open 

interval

~

~

30

113

--

-

-

-

~

--

--

-

70

65

-

101

--

50

127

-

--

--

--

70

65

--

93

--

51

90

64

--

-

85

325

238

--

-

303

WfH . Type of log completion ., . , 

, available date

~

09-21-77

06-30-86

08-28-80

11-06-84

-

~

~

10-07-77

05-14-59

-

~

04-27-92

06-26-90

-

10-10-84

--

10-27-83

09-17-91

-

04-06-82

11-19-78

11-06-84

-

03-04-94

07-09-89

09-04-78

09-01-93

~

09-10-85

01-29-91

09-02-91

-

~

02-02-93

01-06-90

10-17-92

-

~

04-28-94

-

D

D

D

D

-

D

-

-

D

-

-

-

-

D

-

D

-

D

-

D

D

-

D

D

D

-

D

D

D

D

-

D

-

D

-

D

-

-

D

D

D

-

-

D

Primary 

use of 

water

H

H

H

F

H

H

H

H

H

H

H

U

H

I

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

42 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Water level

Date of 

measurement

08-03-94

07-26-91

12-19-95

12-19-95

11-17-95

11-17-95

11-19-95

11-17-95

08-24-95

11-18-95

11-17-95

12-13-95

11-18-95

11-18-95

11-18-95

11-17-95

11-17-95

09-18-95

11-17-95

11-18-95

11-19-95

11-18-95

11-19-95

11-17-95

11-17-95

__

11-17-95

11-17-95

11-18-95

11-19-95

11-18-95

11-18-95

11-17-95

11-17-95

11-18-95

11-19-95

11-17-95

11-17-95

11-18-95

11-18-95

11-18-95

11-17-95

09-20-95

11-18-95

Depth to 

water 

(ft)

31.62

40.21

11.39

48.16

23.44

35.71

23.05

29.43

33.67

30.13

4.04

4.95

13.90

3.04

13.54

10.63

47.61

61.54

64.09

58.58

15.48

111.48

92.72

62.10

61.67

._

64.34

48.03

33.22

22.04

46.07

23.56

20.32

31.72

63.93

37.38

33.33

38.99

31.84

91.93

100.52

236.79

204.02

196.85

Yield 

(gal/min)

20

25

75

30

_

~

25

_

30

_.

25

10

-

30

30

30

50

30

~

15

15

22

20

30

~

30

__

10

20

20

8

20

Source of 

yield 

data

-

D

D

D

D

_

-

-

-

D

_

-

-

-

D

_

D

-

D

-

D

D

-

D

D

D

-

D

D

D

D

-

D

-

D

_

D

-

-

D

D

D

-

-

D

Specific 

capacity 

|(gal/min)/ 

ft]

0.1

2.1

1.1

2.5

..

~

2.5

_

~

1.3

_

1.3

~

-

2.0

6.0

.9

-

2.5

.6

2.4

..

.9

1.4

__

.4

1.1

2.2

.1

1.0

Date of field 

waterquality 

parameter 

measurement

08-03-94

07-25-91

10-25-95

10-25-95

08-22-94

08-28-95

08-16-94

08-15-94

08-24-95

08-15-94

09-28-94

08-18-95

08-28-95

08-04-94

08-02-94

08-18-94

08-17-95

08-09-94

08-10-94

08-09-94

08-10-94

08-04-94

08-08-94

08-18-94

08-24-94

08-23-94

08-10-94

08-15-94

08-16-94

08-18-94

08-24-94

08-16-94

08-28-94

08-17-95

08-15-94

08-17-95

08-22-94

08-19-94

08-03-94

08-02-94

08-02-94

08-23-94

08-03-94

08-15-94

Specific

conduct- I; ' field 

ance, , . . 

, ,7 (stand- field v . ._. 

. . . ard units) (US/cm)

138

110 7.0

63.0 6.6

143 7.2

264

354

338

286

283

292

216

._

297

443

340

504

306

421

404

409

419

277

359

386

306

366

351

353

267

272

327

214

228

276

334

263

199

124

185

274

339

343

337

315

271

Water 

temperature, 

field 

(°C)

14.5

12.0

11.0

14.0

13.5

12.5

13.0

13.5

14.0

13.0

13.5

11.0

16.0

11.5

10.5

13.5

12.5

12.0

11.0

11.5

12.5

12.5

12.0

13.5

13.5

14.0

12.5

12.5

12.0

12.0

11.0

11.5

11.5

12.0

13.0

11.5

11.0

10.5

12.0

14.0

12.5

15.5

15.5

16.5

Location number

10N20W02ABBC01

10N20W10ACBC01

10N20W10CBBD01

10N20W11CDCD01

10N20W12ACDB01

10N20W12ADCB01

10N20W12ADDC01

10N20W12DAAA01

10N20W12DABD01

10N20W12DADA01

10N20W12DDDC01

10N20W13BBA01

10N19W05CCCC01

10N19W05CCCD01

10N19W05CDCC01

10N19W05DCDD01

10N19W06CDCB01

10N19W06CDDA01

10N19W06CDDD01

10N19W06DCCC01

10N19W06DCDA01

10N19W06DDCC01

10N19W07ADBC01

10N19W07BAAD01

10N19W07BACB01

10N19W07BCBB01

10N19W07BDAD01

10N19W07BDBB01

10N19W07CAAB01

10N19W07CABD01

10N19W07CACC01

10N19W07CDAA01

10N19W07CDBA01

10N19W07CDCC01

10N19W07DABB01

10N19W07DBBC01

10N19W07DBDA01

10N19W07DDCD01

10N19W07DDDC01

10N19W08ABBC01

10N19W08ADAD01

10N19W08ADDC01

10N19W08BADD01

10N19W08BBDD01

10N19W08BCAD01

TABLE 4 43
Table 4. Records of selected wells (Continued)

Location number

10N19W08BCBB01

10N19W08BCCC01

10N19W08BDAB01

10N19W08BDBB01

10N19W08CBAA01

10N19W08CBDD01

10N19W08CDAC01

10N19W08CDBD01

10N19W08DAAC01

10N19W08DBBD01

10N19W08DCCB01

10N19W08DCCC01

10N19W08DCCC02

10N19W08DCCD01

10N19W09ABCC01

10N19W09BCCC01

10N19W16BBBC01

10N19W17BAAA01

10N19W17BBDA01

10N19W17BCAB01

10N19W17BCCC01

10N19W17DBBC01

10N19W18AAAA01

10N19W18AADB01

10N19W18ABAD01

10N19W18ADDC01

10N19W18BCCB01

10N19W18DBBA01

10N19W19BDAD01

10N19W19DDAA01

10N19W20BAAD01

10N19W21CBBA01

10N19W29ABAC01

10N19W30CACD01

09N20W19ADCA01

09N20W20ACAB01

09N20W20ACAD01

09N20W20CDCD01

09N20W21ACCB01

09N20W21CCAC01

09N20W26BACC02

09N20W28CCBB01

09N20W29ADCC01

09N19W33BDBC01

08N21W27DCBC01

Altitude of 

land 

surface 

(ft)

3,382

3,380

3,433

3,416

3,400

3,374

3,406

3,397

3,482

3,438

3,454

3,462

3,460

3,468

3,575

3,492

3,518

3,436

3,412

3,388

3,372

3,485

3,342

3,326

3,310

3,352

3,220

3,306

3,280

3,490

3,490

3,595

3,672

3,470

3,870

3,492

3,475

3,500

3,330

3,348

3,363

3,190

3,390

3,812

3,650

Geologic 

unit

Tabr

Tabr

Tabr

Tabr

Qaf

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Qaf

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Taf

Tabr

Tabr

Tabr

Qaf

Tabr

Tabr

Qaf

Tabr

Qaf

Qaf

Depth of 

well 

(ft)

200

158

319

295

--

69

124

107

210

261

220

~

168

187

-

290

~

--

~

--

._

215

75

95

65

122

50

140

65

~

400

389

356

211

90

60

198

160

37

125

552

40

75

228

30

Casing 

diameter 

(in.)

6.0

6.0

6.0

6.0

--

6.0

6.0

6.0

6.0

--

__

-

6.0

6.0

-

6.0

--

~

«

-

__

6.0

6.0

6.0

--

6.0

~

--

6.0

--

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

-

6.0

6.0

~

6.0

6.0

6.0

Type of 

finish

P

P

S

P

-

P

P

P

S

-

-

-

P

S

-

S

-

-

-

-

-

o

P

P

-

S

-

-

P

-

.

P

P

o

P

P

P

P

-

P

P

-

-

P

P

Depth to 

top 

of open 

interval

180

150

311

287

-

64

114

99

143

-

~

160

182

-

235

~

-

--

--

67

59

-

114

~

-

57

~

__

381

300

-

20

20

40

60

~

100

310

~

~

60

22

Well 

completion 

date

06-26-90

07-06-89

04-30-90

06-23-89

~

02-23-84

09-14-89

08-17-88

06-20-91

-

-

06-04-91

11-12-92

-

04-24-92

~

~

~

-

09-14-78

07-04-89

06-01-83

~

07-23-91

-

-

09-27-77

~

00-00-93

05-24-95

10-25-77

03-26-79

01-01-78

01-01-69

05-24-93

08-08-87

--

04-20-93

04-28-90

~

00-00-89

10-21-78

05-24-78

Type of log 

available

D

D

D

D

-

D

D

D

D

-

-

-

D

D

-

D

-

-

-

-

-

D

D

D

-

D

-

-

D

-

-

D

D

D

D

-

D

D

-

D

D

-

-

D

D

Primary 

use of 

water

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

I

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

S

u

H

H

H

H

44 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Water level

Date of 

measurement

11-18-95

11-19-95

11-17-95

08-08-94

08-03-94

11-17-95

11-17-95

~

11-17-95

11-17-95

11-17-95

08-19-94

12-19-95

06-06-95

~

11-17-95

11-18-95

11-17-95

11-17-95

11-17-95

11-17-95

12-11-95

08-24-94

11-17-95

11-17-95

11-17-95

01-21-95

11-19-95

10-25-95

10-25-95

10-24-95

10-24-95

10-24-95

10-23-95

10-11-95

12-19-95

09-14-95

10-11-95

12-14-95

12-19-95

--

10-23-95

~

12-19-95

Depth to 

water 

(ft)

144.77

128.79

227.08

214.34

61.22

51.01

74.39

68.53

198.23

115.69

136.80

139.97

150.85

-

56.95

203.84

119.35

90.62

84.35

93.95

179.32

45.23

42.91

30.28

81.93

26.95

68.82

50.60

167.94

205.56

362.63

312.98

16.38

32.95

27.39

22.13

10.51

.21

79.14

~

47.29

~

7.11

Yield 

(gal/min)

10

30

15

18

~

30

30

30

5

~

_

20

50

~

9

~

__

15

30

40

~

40

12

~

__

10

12

10

3

2

4

10

~

15

218

~

~

8

40

Source of 

yield 

data

D

D

D

D

-

D

D

D

D

-

_

-

D

D

-

D

-

-

-

-

.

D

D

D

-

D

-

-

D

-

_

D

D

D

-

0

D

D

-

D

D

-

-

D

D

Specific 

capacity 

[(gal/min)/ 

ft]

.5

1.5

.7

.7

~

1.8

.8

3.0

~

_

~

.3

1.4

~

26.7

~

~

~

_

.4

1.5

3.3

~

2.0

.8

--

..

.5

.6

5.0

.1

.1

.3

.1

~

4.8

~

~

2.5

Date of field 

waterquality 

parameter 

measurement

08-16-94

08-10-94

08-08-94

08-08-94

08-03-94

08-16-94

08-09-94

08-18-95

08-23-94

08-28-95

08-28-95

08-19-94

10-26-95

~

08-02-94

08-18-94

08-24-94

08-08-94

08-19-94

08-19-94

_

12-11-95

08-24-94

08-28-95

--

_

09-13-95

10-25-95

10-25-95

10-24-95

10-24-95

10-24-95

10-24-95

10-23-95

10-11-95

06-03-96

09-14-95

10-11-95

12-14-95

..

10-11-95

10-23-95

08-22-95

06-03-96

Specific 

conductance, 

field

(jaS/cm)

294

386

243

291

306

198

338

257

168

195

274

280

258

341

201

184

237

182

193

_

210

168

175

~

_

186

214

210

191

243

274

236

141

118

128

230

42.9

287

__

193

256

177

70.6

pH,

field 

(standard units)

~

_.

-

_

7.2

~

__

~

_

7.3

~

__

6.9

7.0

7.3

7.1

7.0

7.4

7.2

6.4

6.5

6.5

8.3

6.2

7.4

._

6.6

6.8

7.4

6.6

Water 

temperature, 

field 

(°C)

15.0

12.0

15.0

15.5

11.0

10.0

10.5

10.0

13.5

13.5

11.0

11.0

11.0

11.0

11.0

13.5

11.5

9.5

10.5

__

12.0

11.5

11.0

~

__

10.0

10.5

14.0

13.5

14.5

13.5

11.0

12.0

11.0

10.0

10.0

12.5

10.5

..

10.5

10.5

18.0

8.5

Location number

10N19W08BCBB01

10N19W08BCCC01

10N19W08BDAB01

10N19W08BDBB01

10N19W08CBAA01

10N19W08CBDD01

10N19W08CDAC01

10N19W08CDBD01

10N19W08DAAC01

10N19W08DBBD01

10N19W08DCCB01

10N19W08DCCC01

10N19W08DCCC02

10N19W08DCCD01

10N19W09ABCC01

10N19W09BCCC01

10N19W16BBBC01

10N19W17BAAA01

10N19W17BBDA01

10N19W17BCAB01

10N19W17BCCC01

10N19W17DBBC01

10N19W18AAAA01

10N19W18AADB01

10N19W18ABAD01

10N19W18ADDC01

10N19W18BCCB01

10N19W18DBBA01

10N19W19BDAD01

10N19W19DDAA01

10N19W20BAAD01

10N19W21CBBA01

10N19W29ABAC01

10N19W30CACD01

09N20W19ADCA01

09N20W20ACAB01

09N20W20ACAD01

09N20W20CDCD01

09N20W21ACCB01

09N20W21CCAC01

09N20W26BACC02

09N20W28CCBB01

09N20W29ADCC01

09N19W33BDBC01

08N21W27DCBC01

TABLE 4 45
Table 4. Records of selected wells (Continued)

Location number

08N20W01ACCB01

08N20W01DAAD01

08N20W01DABD01

08N20W02CBDB01

08N20W11BDAA01

08N20W11CCAD01

08N20W12BAAA01

08N20W13BBDB01

08N20W14ABDB01

08N20W19BAAD03

08N20W23CDDD01

08N20W26BAAC01

08N20W30CDAB01

08N19W04BDAA01

08N19W07CBBD01

08N19W10BBCA01

08N19W11CDBB01

07N21W13BBAD01

07N21W25CABC01

07N21W36DDDC01

07N20W32DDDA02

07N20W34CCCD01

07N20W34CDDB01

07N20W36CCCA01

06N21W01ACDA01

06N21W01CADD01

06N21W01CBAB01

06N21W01CBAB02

06N21W02ABBD01

06N21W02CADD01

06N21W03ACBA01

06N21W03CAAC01

06N21W03CCDD01

06N21W03CDAC01

06N21W03DDAA01

06N21W09DADA01

06N21W10BDDD01

06N21W11ABAA01

06N21W11CAAA01

06N21W11CBCA01

06N21W11CBDC01

06N21W11CDCB01

06N21W11DCCA01

06N21W12ABAB01

06N21W12BDDD01

Altitude of 

land 

surface 

(ft)

3,762

3,828

3,822

3,535

3,585

3,610

3,810

3,802

3,690

3,393

3,545

3,510

3,407

3,950

3,893

4,079

4,260

3,590

3,489

3,487

3,473

3,546

3,568

3,741

3,520

3,547

3,590

3,590

3,750

3,692

3,839

3,852

3,965

3,825

3,760

4,045

3,885

3,632

3,632

3,695

3,705

3,630

3,630

3,502

3,545

Geologic 

unit

Taf

Taf

Taf

Taf

Tabr

Tabr

Taf

Tabr

Tabr

Tabr

Taf

Tabr

Qaf

Tabr

Taf

Tabr

Tabr

Tabr

Tabr

Qalt

Qalt

Tabr

Tabr

Taf

Qaf

Tabr

Tabr

Qaf

Taf

Tabr

Tabr

Tabr

Taf

Tabr

Qaf

Tabr

Taf

Tabr

Tabr

Qaf

Tabr

Tabr

Qaf

Tabr

Tabr

Depth of 

well 

(ft)

135

70

132

222

279

308

108

525

367

52

232

440

39

56

117

70

50

100

48

31

40

90

94

35

63

80

89

137

42

42

40

320

34

412

136

60

36

180

75

42

270

Casing 

diameter 

(in.)

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

48

6.0

6.0

6.0

6.0

6.0

8.0

6.0

6.0

_.

8.0

6.0

6.0

4.0

5.5

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

«

4.0

6.0

Type of 

finish

P

0

0

-

P

o

P

o

P

0

0

P

P

P

0

o

P

0

P

P

0

0

0

.

-

o

-

-

-

s

0

P

s

P

P

P

-

P

-

o

0

P

-

-

P

Depth to 

top 

of open 

interval

127

~

~

-

271

100

~

362

-

145

34

51

--

..

42

35

23

__

..

-

_

108

_

37

20

26

352

128

-

_

67

__

45

Well 

completion 

date

04-15-89

08-10-77

01-27-78

00-00-80

11-25-77

08-06-85

01-01-89

01-01-69

01-01-88

06-20-57

07-20-84

09-30-92

08-09-89

02-28-85

00-00-56

02-15-45

12-21-79

06-13-79

10-17-87

10-20-76

00-00-62

06-09-80

03-05-94

._

00-00-30

10-25-78

00-00-92

10-24-77

10-29-73

11-16-71

04-01-91

03-07-78

04-10-78

09-04-81

02-08-79

07-26-78

04-22-94

09-22-90

06 - 53

06-22-76

Type of log 

available

D

D

D

-

D

D

D

-

-

D

D

D

D

D

-

_

D

D

D

D

_

D

D

_

D

D

.

-

-

D

D

D

D

D

D

D

_

D

_

D

D

D

-

_

D

Primary 

use of 

water

H

U

H

H

H

H

H

H

H

U

H

H

P

H

H

H

H

H

H

H

F

H

H

H

H

H

H

U

H

H

H

H

H

U

H

H

H

H

H

H

H

H

H

H

H

46 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
1 1

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o o o o o
Table 4. Records of selected wells (Continued)

Location number

06N21W13BADC01

06N21W13BBAB01

06N21W13CCCD01

06N21W13DBBD01

06N21W14BCBD01

06N21W14BDAC01

06N21W14DAAD01

06N21W15ABBB01

06N21W15ADBC01

06N21W15CDDD01

06N21W21ADDB01

06N21W22AADC01

06N21W22BCCA01

06N21W22CACA01

06N21W23ADAA01

06N21W23BABB01

06N21W23BDDD01

06N21W23CABC01

06N21W23CBCB01

06N21W23CDCB01

06N21W23DADA01

06N21W23DADD01

06N21W23DBDA01

06N21W23DDAA01

06N21W23DDAD01

06N21W23DDBB01

06N21W23DDCB01

06N21W23DDDA01

06N21W24BAAC01

06N21W24BDCC01

06N21W24CCAC01

06N21W24CCBB01

06N21W24CCBB02

06N21W24CCCB01

06N21W25DBAA01

06N21W26AADD01

06N21W26ABAD01

06N21W26BBCA01

06N21W26CBAB01

06N21W26DBAD01

06N21W26DBDD01

06N21W27ADBC01

06N21W27BABA01

06N21W27BBAA01

06N21W34ABCD01

Altitude of 

land 

surface 

(ft)

3,582

3,662

3,622

3,542

3,818

3,718

3,630

3,885

3,850

3,918

4,190

3,820

4,100

3,985

3,638

3,750

3,705

3,815

3,862

3,775

3,618

3,610

3,665

3,610

3,598

3,641

3,615

3,595

3,562

3,590

3,575

3,599

3,601

3,588

3,570

3,565

3,695

3,779

3,705

3,613

3,601

3,835

3,892

4,030

3,762

Geologic 

unit

Tabr

Tabr

Qaf

Qaf

Tabr

Tabr

Tabr

Taf

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Qaf

Qaf

Qaf

Tabr

Tabr

Tabr

Qaf

Tabr

Qaf

Qaf

Qaf

Qaf

Qaf

Qaf

Qaf

Tabr

Tabr

Tabr

Qaf

Qaf

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Qaf

Depth of 

well 

(ft)

43

138

-

-

99

48

54

132

300

120

162

41

132

81

40

29

135

160

86

33

42

30

38

35

38

40

15

40

112

50

16

33

43

66

50

128

60

60

79

174

60

278

126

39

Casing 

diameter 

(in.)

6.0

6.0

~

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

~

6.0

6.0

6.0

6.0

6.0

6.0

-

6.0

6.0

6.0

6.0

12.0

6.0

4.0

6.0

6.0

6.0

6.0

12.0

6.0

6.0

6.0

-

6.0

6.0

6.0

6.0

6.0

-

Type of 

finish

-

P

-

-

P

P

P

-

P

P

P

-

P

P

-

-

P

O

P

0

-

-

-

P

-

P

0

-

O

-

O

-

P

O

-

0

O

-

-

P

P

P

P

0

-

Depth to 

top 

of open 

interval

-

120

-

--

91

40

49

~

100

70

154

--

124

73

~

24

--

140

--

-

--

30

~

30

~

-

--

~

~

26

-

~

-

-

-

74

140

52

140

-

-

Well 

completion 

date

00-00-86

05-19-92

~

--

01-11-79

06-25-92

04-28-69

09-19-62

07-12-80

10-01-79

12-13-90

04-12-55

05-10-89

02-07-83

00-00-38

08-03-73

06-10-85

08-16-78

01-16-80

~

~

~

07-01-91

07 « 47

04-14-89

08-14-68

06 ~ 54

11-27-78

00-00-43

04-27-77

~

08-04-73

-

04-10-46

08-12-68

09-27-67

00-00-83

~

01-15-81

04-22-94

09-26-77

08-16-83

06-12-75

00-00-81

Type of log 

available

-

D

-

-

D

D

D

-

D

D

D

-

D

D

-

-

D

D

D

D

-

-

-

D

-

D

D

-

D

-

D

-

D

-

-

D

D

-

-

D

D

D

D

D

-

Primary 

use of 

water

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

U

U

H

P

H

H

H

H

I

I

H

H

H

H

48 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Water level

Date of 

measurement

10-20-95

~

~

10-20-95

10-26-94

10-20-95

10-20-95

10-20-95

10-20-95

10-20-95

~

-

_.

~

10-20-95

10-20-95

10-20-95

10-20-95

10-20-95

~

-

10-20-95

10-20-95

10-20-95

10-20-95

10-20-95

10-20-95

10-20-95

08-31-94

10-20-95

~

-

10-20-95

10-20-95

10-20-95

10-20-95

12-19-95

10-20-95

10-20-95

10-20-95

12-19-95

08-04-95

Depth to 

water 

(ft)

66.68

~

~

13.39

4.14

89.85

135.60

44.87

129.19

91.49

~

-

..

102.25

94.92

48.52

5.22

6.78

~

-

8.14

4.69

3.52

4.38

17.71

54.92

20.83

9.36

7.41

-

35.98

36.58

34.54

15.14

31.37

37.74

44.38

66.34

81.27

16.46

Yield 

(gal/min)

_.

25

15

22

20

50

5

9

10

60

12

4

-

._

20

10

10

12

_.

-

50

~

50

40

7

~

15

15

15

480

40

8

10

30

20

5

9

Source of 

yield 

data

.

D

-

-

D

D

D

O

D

S

D

0

D

D

-

_

D

D

D

D

_

-

-

D

-

D

D

-

D

-

D

-

D

R

R

D

D

-

-

D

D

D

D

D

-

Specific 

capacity 

[(gal/min)/ 

ft]

__

3.1

.8

.8

4.0

.1

2.0

.7

~

.2

~

_

1.0

.2

.2

1.2

_

1.7

~

1.9

1.3

.4

~

.9

15.0

-

4.0

.1

.2

.3

1.7

.8

Date of field 

waterquality 

parameter 

measurement

04-18-95

04-18-95

10-26-94

05-01-95

04-19-95

10-26-94

10-26-94

04-19-95

06-12-95

10-26-94

10-25-94

04-20-95

08-29-94

08-29-94

10-25-94

10-25-94

08-30-94

06-12-95

09-13-94

08-30-94

09-01-94

08-31-94

07-10-95

08-31-94

08-31-94

08-31-94

08-31-94

08-31-94

10-25-94

04-19-95

08-31-94

08-31-94

08-31-94

08-30-94

12-14-95

08-19-94

08-18-94

08-30-94

08-30-94

-

09-13-94

08-29-94

08-30-94

08-15-95

08-04-95

Specific 

conductance, 

field

(p.S/cm)

143

90.0

89.9

106

57.3

82.2

58.3

75.8

101

50.3

122

40.1

124

120

47.2

28.4

36.2

79.0

110

105

48.4

54.0

43.9

50.8

51.7

51.4

73.3

59.2

92.9

175

63.3

60.2

57.3

69.3

293

90.3

212

45.3

97.9

-

107

108

99.2

83.9

100

pH, 

field 

(standard units)

7.8

7.6

6.2

6.4

7.0

7.1

6.1

6.7

7.7

6.4

7.2

6.7

7.0

6.4

6.2

6.1

6.3

7.1

7.1

6.6

6.1

6.1

6.7

6.3

6.3

6.3

6.6

6.2

6.6

9.4

6.2

6.3

6.5

6.3

7.2

6.6

7.2

6.3

6.7

~

7.2

6.4

6.7

7.8

6.6

Water 

temperature, 

field

(°Q

11.5

11.0

11.5

11.0

10.0

12.0

9.0

10.0

12.0

9.5

11.0

9.5

11.0

13.5

11.5

11.5

12.5

10.0

11.0

12.0

10.5

11.0

11.0

14.5

12.5

10.0

10.0

11.0

9.0

11.0

12.5

14.0

14.5

11.0

12.0

10.0

11.5

10.5

11.5

~

13.0

10.0

12.0

11.0

11.0

Location number

06N21W13BADC01

06N21W13BBAB01

06N21W13CCCD01

06N21W13DBBD01

06N21W14BCBD01

06N21W14BDAC01

06N21W14DAAD01

06N21W15ABBB01

06N21W15ADBC01

06N21W15CDDD01

06N21W21ADDB01

06N21W22AADC01

06N21W22BCCA01

06N21W22CACA01

06N21W23ADAA01

06N21W23BABB01

06N21W23BDDD01

06N21W23CABC01

06N21W23CBCB01

06N21W23CDCB01

06N21W23DADA01

06N21W23DADD01

06N21W23DBDA01

06N21W23DDAA01

06N21W23DDAD01

06N21W23DDBB01

06N21W23DDCB01

06N21W23DDDA01

06N21W24BAAC01

06N21W24BDCC01

06N21W24CCAC01

06N21W24CCBB01

06N21W24CCBB02

06N21W24CCCB01

06N21W25DBAA01

06N21W26AADD01

06N21W26ABAD01

06N21W26BBCA01

06N21W26CBAB01

06N21W26DBAD01

06N21W26DBDD01

06N21W27ADBC01

06N21W27BABA01

06N21W27BBAA01

06N21W34ABCD01

TABLE 4 49
Table 4. Records of selected wells (Continued)

Location number

06N20W01BABA01

06N20W01BABB01

06N20W01CDCD01

06N20W02AADC01

06N20W02BBDA01

06N20W02CCAA01

06N20W02DCDC01

06N20W03BDBB01

06N20W03BDCC01

06N20W03CCDB01

06N20W04AABC01

06N20W04ACCD01

06N20W04ADCD01

06N20W04CCCD01

06N20W04DCCB01

06N20W09BDDD01

06N20W09CBCC01

06N20W09CCDB01

06N20W09DCAB01

06N20W10AADC01

06N20W10ABDB01

06N20W10BCAC01

06N20W10CACB01

06N20W10DADD01

06N20W10DBBB01

06N20W10DCAB01

06N20W11CCBD01

06N20W11DBAA01

06N20W12ABDB01

06N20W12CCCD01

06N20W13BADD01

06N20W13BCAC01

06N20W14ACDD01

06N20W14BADB01

06N20W14BBBB01

06N20W14CAAA01

06N20W14CDAB01

06N20W14DAAA01

06N20W15AACD01

06N20W15BBCC01

06N20W15CACC01

06N20W16AABD01

06N20W16ACCB01

06N20W16ADCB01

06N20W16BAAD01

Altitude of 

land 

surface 

(ft)

3,830

3,810

3,845

3,765

3,679

3,682

3,735

3,570

3,585

3,625

3,528

3,545

3,542

3,504

3,562

3,578

3,562

3,585

3,585

3,722

3,705

3,690

3,722

3,772

3,730

3,742

3,788

3,790

3,875

3,883

3,945

3,948

3,884

3,842

3,792

3,830

3,775

3,922

3,750

3,640

3,694

3,591

3,622

3,672

3,626

Geologic 

unit

Taf

Taf

TYb

TYb

Taf

Qaf

TYb

Tabr

Qaf

Tabr

Qaf

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Tabr

Taf

Taf

Taf

Taf

Taf

Taf

Taf

Taf

Taf

Qaf

Taf

TYb

Taf

Taf

Taf

Tabr

Taf

Taf

Taf

Taf

Tabr

Taf

Tabr

Tabr

Tabr

Tabr

Depth of 

well 

(ft)

45

265

120

115

--

__

25

43

-

34

55

100

50

58

125

90

99

~

160

66

167

200

60

46

68

174

135

22

63

35

-

120

80

1,110

78

75

~

65

--

59

74

150

110

180

Casing 

diameter 

(in.)

6.0

6.0

8.0

6.0

--

..

6.0

6.0

-

6.0

6.0

6.0

6.0

6.0

6.0

6.0

~

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

~

6.0

__

~

6.0

6.0

4.0

6.0

6.0

~

-

6.0

6.0

6.0

6.0

6.0

Type of 

finish

0

P

P

P

-

-

-

P

-

-

0

O

0

0

P

-

-

0

-

P

P

O

O

-

P

_

s

P

-

O

-

-

P

P

P

s

-

-

-

-

s

O

P

O

P

Depth to 

top 

of open 

interval

40

20

50

-

-

36

--

--

-

--

50

-

--

--

130

47

~

--

--

38

111

95

--

~

--

80

50

209

54

-

--

--

34

-

120

-

140

Well 

completion 

date

04-18-69

03-10-78

06-21-79

08-03-91

--

00-00-20

07-10-73

-

~

01-04-75

03-04-93

05-09-77

04-06-83

12-13-91

~

08-01-90

~

05-27-88

04-28-87

~

11-07-74

~

07-07-93

__

04-27-95

11-22-77

~

09-26-73

~

03-22-83

06-24-76

04-06-79

05-13-93

00-00-82

00-00-79

~

~

05-13-93

06-23-77

08-28-79

01-12-78

04-07-78

Type of log 

available

D

D

D

D

-

-

-

D

-

-

D

D

D

D

D

-

-

D

-

D

D

D

D

-

D

.

D

D

-

D

-

-

D

D

D

D

-

-

-

-

D

D

D

D

D

Primary 

use of 

water

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

H

I

H

H

S

H

U

H

H

H

H

H

H

H

H

S

H

50 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Water level

Date of 

measurement

08-24-95

11-10-95

11-10-95

11-10-95

11-10-95

07-27-95

11-10-95

11-10-95

12-19-95

~

11-10-95

11-10-95

06-14-95

11-10-95

11-10-95

11-10-95

11-10-95

11-10-95

11-10-95

11-10-95

11-10-95

~

11-10-95

11-10-95

11-10-95

~

05-03-95

06-14-95

11-10-95

~

~

11-10-95

12-19-95

11-10-95

08-01-95

08-21-95

11-10-95

11-10-95

11-10-95

~

11-10-95

11-10-95

11-10-95

Depth to 

water 

(ft)

8.08

13.20

4.55

45.25

7.93

1.34

8.23

17.52

23.68

~

7.26

34.02

24.93

19.67

35.00

49.44

60.35

67.74

36.00

27.80

15.68

~

137.32

18.22

22.24

43.24

6.48

29.54

-

14.21

66.80

15.56

flowing

94.59

30.62

61.15

21.73

-

74.80

73.19

87.33

Yield 

(gal/min)

3

2

15

3

~

__

~

25

~

12

15

8

50

18

__

20

~

15

35

~

20

20

10

_.

30

20

10

~

25

20

32

20

~

~

~

20

35

10

10

15

Source of 

yield 

data

D

D

D

D

-

_

-

D

-

-

D

D

D

D

D

_

-

D

-

D

D

-

D

0

D

_

D

D

-

D

-

-

D

D

D

D

-

-

-

-

D

D

D

D

D

Specific 

capacity 

[(gal/min)/ 

ft]

.1

.2

-

_.

1.1

«

~

_

.2

2.2

1.5

~

.1

1.5

.7

.8

_.

.3

.4

.3

~

.6

.6

.7

.5

~

~

.9

1.8

.2

.3

.2

Date of field 

waterquality 

parameter 

measurement

07-26-95

06-14-95

07-24-95

07-11-95

07-26-95

07-12-95

07-24-95

07-12-95

05-04-95

07-24-95

07-27-95

06-14-95

05-04-95

06-14-95

07-26-95

08-03-95

05-02-95

05-03-95

07-12-95

05-04-95

07-12-95

06-14-95

07-25-95

07-25-95

07-25-95

06-13-95

05-03-95

06-14-95

05-04-95

06-13-95

07-12-95

05-03-95

05-02-95

~

06-12-95

08-01-95

08-21-95

06-13-95

05-04-95

07-25-95

08-03-95

05-02-95

07-27-95

05-04-95

Specific 

conductance, 

field

(^iS/cm)

396

395

453

661

558

532

328

505

463

449

385

359

363

436

595

332

375

588

775

419

429

600

420

411

384

598

582

232

750

864

637

578

440

~

248

555

517

580

481

505

526

484

577

364

pH, 

field 

(standard units)

8.0

7.4

7.3

7.9

7.6

7.5

7.7

7.2

7.6

7.3

7.4

7.6

7.5

7.5

7.4

7.5

7.5

7.2

7.6

8.0

7.8

7.9

7.7

7.9

8.0

7.8

7.5

7.8

7.6

7.3

7.6

7.6

7.6

~

7.3

7.5

8.1

7.6

7.5

7.5

7.5

7.5

7.5

7.5

Water 

temperature, 

field

(°C)

14.5

10.5

15.0

12.5

10.5

12.0

12.0

11.5

10.5

11.5

12.5

12.0

10.5

13.0

12.0

13.0

12.5

12.0

12.5

10.0

12.0

13.0

13.0

12.0

10.5

12.5

11.5

11.0

11.5

12.0

12.5

9.5

11.0

~

10.0

14.5

18.0

12.0

11.5

11.5

15.0

11.5

14.5

10.0

Location number

06N20W01BABA01

06N20W01BABB01

06N20W01CDCD01

06N20W02AADC01

06N20W02BBDA01

06N20W02CCAA01

06N20W02DCDC01

06N20W03BDBB01

06N20W03BDCC01

06N20W03CCDB01

06N20W04AABC01

06N20W04ACCD01

06N20W04ADCD01

06N20W04CCCD01

06N20W04DCCB01

06N20W09BDDD01

06N20W09CBCC01

06N20W09CCDB01

06N20W09DCAB01

06N20W10AADC01

06N20W10ABDB01

06N20W10BCAC01

06N20W10CACB01

06N20W10DADD01

06N20W10DBBB01

06N20W10DCAB01

06N20W11CCBD01

06N20W11DBAA01

06N20W12ABDB01

06N20W12CCCD01

06N20W13BADD01

06N20W13BCAC01

06N20W14ACDD01

06N20W14BADB01

06N20W14BBBB01

06N20W14CAAA01

06N20W14CDAB01

06N20W14DAAA01

06N20W15AACD01

06N20W15BBCC01

06N20W15CACC01

06N20W16AABD01

06N20W16ACCB01

06N20W16ADCB01

06N20W16BAAD01

TABLE 4 51
Table 4. Records of selected wells (Continued)

Location number

06N20W16DDDB01

06N20W17AACA01

06N20W17ADCC01

06N20W19CCCC02

06N20W29BADB01

06N20W30DBCC01

06N19W06CBCA01

06N19W07BABC01

05N21W03ACBA01

05N21W12BCAB01

05N21W15AABD01

05N21W15AADB01

05N21W22CDAD01

05N21W23BBAA01

05N21W27DDBD01

05N21W36DCC02

05N20W10BAAC01

05N20W17BADC01

05N20W17CBAB01

05N20W17CDDB01

05N20W18ABDA01

05N20W18ADBA01

05N20W18CACC01

05N20W18DACA01

05N20W18DBAA01

05N20W18DCDB01

05N20W30BDCD01

04N21W14CBAA01

04N21W16DDDD01

04N21W35CCBA01

03N21W10DADD01

03N21W14BBAC01

03N21W14CAAA01

03N21W15CBBB01

03N21W15CCCD01

02N21W01CACD01

02N20W07BCCC01

02N20W07CABC01

Altitude of 

land 

surface 

(ft)

3,702

3,539

3,602

3,560

3,610

3,581

4,100

3,965

3,818

3,655

3,925

3,900

4,085

3,882

3,770

3,702

3,998

3,805

3,825

3,942

3,810

3,846

3,678

3,905

3,885

3,880

3,728

3,795

4,085

3,844

3,888

3,880

3,895

4,095

4,140

4,120

4,055

4,045

Geologic 

unit

Taf

Tabr

Qaf

Qalt

Qaf

Qalt

TYb

Tabr

Tabr

Tabr

Tabr

Qgt

Tabr

Taf

Tabr

Qalt

Taf

Tabr

Taf

Taf

Taf

Taf

Tabr

Taf

Taf

Taf

Qaf

Tabr

Taf

Tabr

Tabr

Tabr

Tabr

Taf

Taf

Tabr

Tabr

Qalt

Depth of 

well 

(ft)

124

-

~

40

85

109

420

220

55

67

301

25

110

54

129

29

80

260

26

78

154

269

75

85

93

88

36

56

165

100

70

85

80

124

111

280

60

--

Casing 

diameter 

(in.)

6.0

~

~

6.0

6.0

12.0

6.0

6.0

6.0

--

6.0

--

~

6.0

6.0

8.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

6.0

8.0

8.0

6.0

6.0

6.0

6.0

6.0

Type of 

finish

0

-

-

O

0

p

p

p

s

-

p

-

-

p

p

p

0

p

p

p

s

p

-

-

s

p

p

p

-

-

p

-

p

p

p

_

O

-

Depth to 

top 

of open 

interval

~

--

-

-

~

87

120

40

50

--

220

-

--

28

124

14

145

18

66

146

154

85

76

26

48

-

40

61

116

101

__

-

Well 

completion 

date

03-24-77

~

~

09-04-70

05-16-84

06-18-75

02-23-77

05-01-86

09-17-91

~

09-08-72

-

-

06-26-84

04-27-92

06-28-85

08-23-77

07-30-87

07-21-91

12-18-92

03-07-90

00-00-78

01-27-64

~

07-13-91

04-29-83

09-12-83

01-18-89

~

~

09-03-73

~

11-12-81

06-06-82

08-08-76

05-03-78

~

Type of log 

available

D

-

-

-

D

D

D

D

D

-

D

-

-

D

D

D

D

D

D

D

D

-

D

-

D

D

D

D

-

-

D

-

D

D

D

_

D

-

Primary 

use of 

water

H

H

H

U

C

P

H

H

H

H

H

S

H

H

H

I

S

H

H

H

H

H

S

H

H

H

H

H

H

I

P

P

P

U

H

H

U

H

52 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Water level

Date of 

measurement

-

05-02-95

12-13-95

12-19-95

07-16-91

07-27-95

12-19-95

08-04-95

12-12-95

07-15-91

12-14-95

08-03-95

12-12-95

08-03-95

06-04-96

12-12-95

08-02-95

08-02-95

08-21-95

08-02-95

~

12-14-95

08-02-95

08-02-95

08-02-95

12-19-95

12-13-95

12-13-95

07-12-91

07-12-91

~

07-12-91

12-19-95

06-04-96

12-19-95

07-11-91

12-13-95

Depth to 

water 

(ft)

69.97

12.09

16.81

4.97

229.51

28.88

24.38

50.05

156.96

8.21

91.76

17.04

20.50

4.65

25.98

26.29

2.11

36.64

120.49

~

50.20

26.65

70.00

57.76

22.42

30.79

66.24

10.92

11.77

7.53

69.84

68.11

24.00

29.48

35.65

Yield 

(gal/min)

75

40

500

9

10

20

~

16

5

5

30

99

20

12

18

16

20

~

30

12

9

100

30

8

-

500

250

10

8

..

20

~

Source of 

yield 

data

D

-

-

-

D

D

D

D

D

-

D

S

-

D

D

D

D

D

D

D

D

-

0

-

D

D

D

D

S

-

D

-

D

D

D

_

D

-

Specific 

capacity 

[(gal/min)/ 

ft]

.8

1.0

6.9

.1

.7

-

.1

~

.2

.3

9.0

.7

.1

1.8

.7

.8

-

.6

.5

7.7

2.8

.4

~

__

.1

.3

_.

1.0

-

Date of field 

waterquality 

parameter 

measurement

05-03-95

05-03-95

05-02-95

08-21-95

_

07-27-95

07-26-95

08-04-95

08-03-95

12-14-95

12-14-95

08-03-95

08-03-95

08-03-95

06-04-96

12-12-95

08-02-95

08-02-95

08-21-95

08-02-95

08-02-95

12-14-95

08-02-95

08-02-95

08-02-95

12-14-95

12-13-95

12-13-95

~

__

08-19-92

06-04-96

12-13-95

12-13-95

Specific 

conductance, 

field

(jAS/cm)

453

284

307

409

_

739

391

106

42.1

158

40.3

95.8

40.0

108

102

622

424

427

435

426

415

244

310

288

243

188

284

70.4

~

__

159

151

215

69.9

pH,

field 

(standard units)

7.5

6.9

7.2

7.8

_

7.0

7.6

6.3

6.4

8.0

6.8

7.3

6.3

6.6

6.4

7.9

7.8

7.1

8.0

7.7

7.5

7.2

7.8

7.6

7.7

6.8

6.8

6.8

-

__

6.5

6.8

7.1

6.8

Water 

temperature, 

field

(°C)

9.5

10.0

10.5

12.5

__

14.5

12.0

9.0

11.0

11.0

7.5

13.5

11.5

11.5

7.5

9.0

13.5

15.0

11.0

14.5

13.5

10.0

12.5

11.5

13.0

10.0

10.0

10.0

-

._

10.5

9.5

9.5

9.0

Location number

06N20W16DDDB01

06N20W17AACA01

06N20W17ADCC01

06N20W19CCCC02

06N20W29BADB01

06N20W30DBCC01

06N19W06CBCA01

06N19W07BABC01

05N21W03ACBA01

05N21W12BCAB01

05N21W15AABD01

05N21W15AADB01

05N21W22CDAD01

05N21W23BBAA01

05N21W27DDBD01

05N21W36DCC02

05N20W10BAAC01

05N20W17BADC01

05N20W17CBAB01

05N20W17CDDB01

05N20W18ABDA01

05N20W18ADBA01

05N20W18CACC01

05N20W18DACA01

05N20W18DBAA01

05N20W18DCDB01

05N20W30BDCD01

04N21W14CBAA01

04N21W16DDDD01

04N21W35CCBA01

03N21W10DADD01

03N21W14BBAC01

03N21W14CAAA01

03N21W15CBBB01

03N21W15CCCD01

02N21W01CACD01

02N20W07BCCC01

02N20W07CABC01

TABLE 4 53
Table 5. Records of water levels in wells

[*; Asterisk following well number indicates well that is in the monitoring network. Water-level data shown in a hydrograph in figure 21 (following). Water level Depth, in feet below land 

surface. MS, conditions of measurement First column (M) is method of measurement--R, reported; S, steel tape; T, electric tape. Second column (S) is site status-P, pumping; R, recently 

pumped; S, nearby pumping; Z, other]

10N20W10CBBD01 10N20W12ADCBQ1 cont. 1QN20W12DDDC01*

DATE

08-27-93

12-06-93

03-10-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

10.16

12.27

12.66

7.79

12.19

13.01

12.27

9.14

11.70

11.39

10.65

7.12

11.17

11.58

8.93

10.75

MS

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

10N20W11CDCD01

DATE

08-26-93

12-06-93

03-10-94

06-16-94

09-27-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-18-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

48.26

51.82

58.24

52.24

53.17

55.16

47.18

40.16

48.16

52.04

51.73

52.99

46.81

45.81

MS

R

R

R

R

R

R

R

R

R

R

R

R

R

R

10N20W12ACDB01*

DATE

08-22-94

10-30-94

01-16-95

03-31-95

06-03-95

08-19-95

09-22-95

11-17-95

02-25-96

05-16-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

25.13

24.47

24.37

24.28

21.45

24.37

24.28

23.44

23.22

20.29

23.79

23.84

24.05

23.41

23.79

40.52

18.92

20.99

23.66

24.63

MS

S

S

S

S

S

S

S

S

SR

S

T

T

S

S

S

s

s

s

s

s

10N20W12ADCB01

DATE

08-19-95

11-17-95

WATER

LEVEL

36.52

35.71

MS

s

s

DATE

02-26-96

05-15-96

WATER

LEVEL MS

35.49 S

32.80 S

10N20W12ADDC01

DATE

10-30-94

01-19-95

03-26-95

06-03-95

08-22-95

09-22-95

11-19-95

05-17-96

WATER

LEVEL MS

24.04 S

23.55 S

23.39 S

24.20 S

25.28 SR

23.46 S

23.05 S

21.32 S

10N20W12DAAA01

DATE

10-25-94

01-18-95

03-31-95

06-03-95

08-19-95

09-22-95

11-17-95

02-24-96

05-15-96

WATER

LEVEL MS

30.08 S

30.08 S

29.99 S

30.30 S

30.34 S

29.97 S

29.43 S

28.48 S

27.66 S

10N20W12DABD01

DATE

08-24-95

09-22-95

11-18-95

02-26-96

05-15-96

WATER

LEVEL MS

33.67 S

33.58 S

32.88 S

32.42 S

29.82 S

10N20W12DADA01*

DATE

08-15-94

10-30-94

01-18-95

03-31-95

06-03-95

08-19-95

09-22-95

11-18-95

02-25-96

05-15-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL MS

30.76 S

30.66 S

30.43 S

30.42 S

30.38 S

30.34 S

30.35 S

30.13 S

26.73 S

26.73 S

36.97 TP

28.90 T

28.73 S

28.28 S

23.53 S

23.33 S

24.20 S

24.49 S

16.59 S

26.12 S

DATE

09-28-94

03-31-95

06-03-95

08-19-95

09-15-95

11-17-95

02-24-96

05-17-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

5.69

5.05

4.39

4.87

4.74

4.04

2.84

1.09

4.26

3.19

2.92

2.44

2.29

1.16

.04

.08

1.31

.30

MS

S

S

S

S

S

S

S

S

T

T

S

S

S

s

s

s

s

s

10N20W13BBA01

DATE

05-14-59

06-15-59

07-11-59

08-19-59

09-10-59

10-16-59

11-18-59

12-16-59

01-25-60

02-09-60

03-06-60

04-11-60

05-02-60

06-17-60

07-24-60

08-25-60

09-05-60

10-14-60

11-14-60

12-14-60

01-06-61

02-15-61

03-22-61

04-08-61

05-15-61

06-05-61

07-07-61

08-12-61

09-05-61

10-10-61

11-22-61

12-06-61

01-10-62

02-15-62

03-16-62

04-27-62

05-26-62

06-17-62

07-24-62

08-15-62

09-17-62

10-16-62

11-19-62

12-20-62

01-10-63

03-19-63

WATER

LEVEL

5.42

2.48

4.64

5.60

4.79

4.52

5.69

5.95

6.49

6.39

6.89

5.54

6.05

3.21

5.56

5.27

4.90

5.19

6.50

6.78

6.95

6.47

6.78

6.38

6.00

3.04

4.87

6.00

5.00

6.08

6.37

6.20

6.24

6.00

6.69

5.09

4.09

3.70

5.24

5.43

4.60

4.50

6.01

5.50

6.23

6.29

MS

-

-

-

-

_

-

_

_

_

-

-

_

-

-

-

..

-

_

_

-

-

-

..

-

-

~

-

-

-

..

..

-

 .

_

_

_

-

-

-

-

-

-

-

54 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 5. Records of water levels in wells (Continued) 

10N20W13BBA01 cont.

DATE MS

04-15-63

05-24-63

06-05-63

07-01-63

07-23-63

09-06-63

10-01-63

11-04-63

12-03-63

03-13-64

03-05-65

09-03-65

03-08-66

09-07-66

11-30-66

03-06-67

06-05-67

09-11-67

11-30-67

03-07-68

05-28-68

08-21-68

12-11-68

06-10-69

09-04-69

12-16-69

03-11-70

06-24-70

11-12-70

02-17-71

06-02-71

09-13-71

12-21-71

03-13-72

06-26-72

09-20-72

12-19-72

03-29-73

06-21-73

09-18-73

12-03-73

03-19-74

06-27-74

10-10-74

01-14-75

04-15-75

06-30-75

08-26-75

11-24-75

02-10-76

05-26-76

08-29-76

11-20-76

02-14-77

06-20-77

09-21-77

12-20-77

02-15-78

05-10-78

08-23-78

11-29-78

02-21-79

05-21-79

09-19-79

03-11-80

06-10-80

10-08-80

01-14-81

04-07-81

07-14-81

05-18-82

08-24-82

WATER

LEVEL

6.40

4.05

3.38

4.22

5.41

5.23

6.07

6.32

6.34

7.03

5.96

5.00

6.55

5.26

6.50

6.70

3.75

6.44

6.10

5.94

4.92

5.30

5.79

4.00

6.31

6.47

6.19

3.85

5.82

5.82

3.21

5.67

6.59

5.57

3.66

5.95

6.79

7.21

5.28

6.66

6.60

6.30

2.77

6.34

7.44

7.55

4.58

5.59

5.68

6.44

4.13

6.15

6.62

8.04

6.16

7.21

6.08

6.88

5.79

6.25

6.71

6.92

5.80

6.74

6.97

5.05

6.81

6.68

6.94

5.74

5.68

6.50

10N20W13BBA01cont. 10N19W05DCDD01 cont.

DATE

10-03-91

11-12-91

02-04-92

05-06-92

06-17-92

07-29-92

10-19-92

01-12-93

04-06-93

08-13-93

10-21-93

02-02-94

06-01-94

10-04-94

12-27-94

05-10-95

07-05-95

07-25-95

10-18-95

12-13-95

02-13-96

05-16-96

08-08-96

10-04-96

11-26-96

01-07-97

12-13-95

02-19-97

04-15-97

06-19-97

08-20-97

10-16-97

WATER

LEVEL

6.26

6.36

6.55

5.45

5.39

6.25

6.32

6.63

6.18

6.00

5.86

6.42

4.86

6.39

6.52

5.86

5.54

5.54

5.62

4.95

4.70

4.28

5.91

6.12

6.23

5.49

4.95

6.15

5.52

3.46

5.87

5.68

MS

-

-

S

S

S

S

S

S

-

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

-

S

S

S

S

S

10N19W05CCCC01

DATE

09-21-95

11-18-95

02-23-96

05-16-96

WATER

LEVEL

13.27

13.90

13.50

14.96

MS

S

S

S

S

10N19W05CCCD01

DATE

09-21-95

11-18-95

02-23-96

05-16-96

WATER

LEVEL

3.26

3.04

3.44

4.85

MS

S

S

S

S

10N19W05CDCC01

DATE

10-30-94

01-19-95

04-03-95

06-05-95

08-18-95

09-22-95

11-18-95

02-23-96

05-15-96

WATER

LEVEL

15.44

15.19

18.03

11.59

11.77

13.89

13.54

15.34

16.40

MS

S

S

S

S

S

SR

S

S

S

10N19W05DCDD01

DATE

10-30-94

WATER

LEVEL

11.47

MS

S

DATE

01-19-95

03-26-95

06-04-95

08-18-95

09-12-95

11-17-95

02-23-96

05-16-96

WATER

LEVEL

12.53

13.58

14.20

11.68

10.57

10.63

11.79

11.01

MS

S

S

S

S

S

S

S

S

10N19W06CDCB01

DATE

10-30-94

01-18-95

03-31-95

06-03-95

08-17-95

09-18-95

11-17-95

02-23-96

WATER

LEVEL

47.82

47.58

47.76

48.12

48.40

48.18

47.61

46.18

MS

S

S

S

S

S

S

S

S

10N19W06CDDA01

DATE

09-18-95

11-18-95

02-23-96

05-15-96

WATER

LEVEL

61.54

60.73

59.40

58.93

MS

S

S

S

S

10N19W06CDDD01*

DATE

08-09-94

10-30-94

01-19-95

04-03-95

06-05-95

08-17-95

09-18-95

11-17-95

02-23-96

05-15-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-21-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

65.66

65.23

64.69

64.80

65.40

65.93

65.21

64.09

62.84

62.27

63.58

61.26

59.86

59.34

58.70

58.25

57.71

52.62

48.89

46.90

MS

S

S

S

S

S

S

S

S

S

S

TR

T

S

S

S

S

S

S

S

S

10N19W06DCCC01

DATE

10-30-94

04-03-95

06-05-95

08-17-95

09-20-95

11-18-95

02-23-96

05-15-96

WATER

LEVEL

60.52

60.01

60.72

61.05

59.95

58.58

57.44

57.35

MS

S

S

S

S

S

S

S

S

TABLE 5 55
Table 5. Records of water levels in wells (Continued) 

10N19W06DCDA01

DATE

10-27-94

01-19-95

03-31-95

06-05-95

08-18-95

09-12-95

11-19-95

02-23-96

05-15-96

WATER

LEVEL

16.52

17.27

17.58

18.09

13.41

14.00

15.48

15.52

16.36

MS

S

S

S

S

S

S

S

SR

S

10N19W06DDCC01*

DATE

08-10-94

10-31-94

01-19-95

03-31-95

06-05-95

08-17-95

09-20-95

11-18-95

02-23-96

05-15-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

111.87

111.44

111.88

111.52

111.94

112.50

112.32

111.48

110.40

109.97

110.47

109.59

112.31

108.09

106.86

106.65

106.44

106.22

105.05

104.92

MS

s

s

s

s

s

s

s

s

s

s

TR

T

S

S

S

S

S

S

S

S

10N19W07ADBC01

DATE

10-30-94

01-19-95

04-05-95

06-06-95

08-17-95

09-13-95

11-19-95

02-24-96

05-16-96

WATER

LEVEL

95.47

95.82

96.37

96.94

96.95

95.39

92.72

92.45

92.70

MS

S

S

S

S

S

S

S

SR

SR

10N19W07BAAD01*

DATE

09-08-94

10-20-94

01-19-95

03-26-95

06-05-95

08-17-95

09-18-95

11-17-95

02-23-96

05-15-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

WATER

LEVEL

63.60

63.40

62.94

63.07

63.58

64.09

63.57

62.10

60.83

60.07

62.35

59.07

58.18

56.94

56.27

58.83

54.97

53.27

MS

S

S

S

S

S

S

S

S

S

S

TR

T

S

S

S

S

S

S

1QN19W07BACB01 10N19W07CABDQ1* cont.

DATE

08-19-97

10-15-97

10-30-94

01-18-95

03-31-95

06-03-95

08-19-95

09-12-95

11-17-95

WATER

LEVEL

47.97

45.52

62.15

61.88

61.79

64.72

62.88

63.45

61.67

MS

S

S

S

S

SR

S

S

S

S

10N19W07BDAD01

DATE

10-27-94

01-19-95

06-05-95

08-19-95

09-22-95

11-17-95

02-23-96

05-15-96

WATER

LEVEL

65.95

65.67

66.39

66.66

65.85

64.34

62.95

62.08

MS

S

S

S

S

S

S

S

S

10N19W07BDBB01

DATE

10-25-94

01-18-95

04-03-95

06-05-95

08-18-95

09-22-95

11-17-95

02-24-96

05-15-96

WATER

LEVEL

48.74

48.50

48.60

49.08

49.42

48.98

48.03

47.83

46.08

MS

S

S

S

S

S

S

S

S

S

10N19W07CAAB01

DATE

10-25-94

01-18-95

04-05-95

06-03-95

08-18-95

09-15-95

11-18-95

02-24-96

05-16-96

WATER

LEVEL

33.89

34.17

34.57

35.29

34.74

34.53

33.22

30.82

29.76

MS

S

S

S

S

S

S

S

S

S

10N19W07CABD01*

DATE

08-16-94

10-25-94

01-18-95

06-03-95

08-18-95

11-19-95

02-24-96

05-16-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

WATER

LEVEL

24.38

22.67

22.85

24.00

22.95

22.04

18.30

18.31

22.52

19.15

19.27

18.23

16.78

15.84

18.45

MS

S

S

S

S

S

SR

S

S

T

T

S

S

S

S

S

DATE

06-24-97

08-19-97

10-15-97

WATER

LEVEL

16.42

18.69

15.72

MS

s

s

s

10N19W07CACC01

DATE

10-30-94

01-18-95

03-31-95

06-03-95

08-19-95

09-22-95

11-18-95

02-26-96

05-15-96

WATER

LEVEL

47.00

48.04

47.01

47.34

47.46

46.74

46.07

44.37

43.53

MS

s

s

s

s

SR

S

s

s

SR

10N19W07CDAA01

DATE

10-3U94

01-19-95

04-05-95

06-03-95

08-18-95

09-22-95

11-18-95

02-25-96

05-15-96

WATER

LEVEL

24.53

24.98

25.49

25.12

24.54

23.91

23.56

20.04

20.23

MS

S

S

S

S

S

S

S

S

SR

10N19W07CDBA01

DATE

10-27-94

01-19-95

04-05-95

06-03-95

08-18-95

09-22-95

11-17-95

02-25-96

05-15-96

WATER

LEVEL

21.53

21.66

22.12

22.93

21.81

21.12

20.32

16.59

16.34

MS

s

s

s

SR

S

SR

S

s

s

10N19W07CDCC01*

DATE

09-28-94

01-21-95

03-31-95

06-03-95

08-18-95

09-13-95

11-17-95

02-25-96

05-16-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

37.80

34.01

33.53

36.63

32.18

33.43

31.72

30.07

29.22

39.35

29.52

28.84

28.37

29.44

29.43

27.01

32.25

25.04

MS

SR

S

S

s

s

T

S

S

S

TR

T

S

S

S

S

Ps

s

s

56 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 5. Records of water levels in wells (Continued) 

10N19WQ7DABB01*

DATE

08-17-95

09-21-95

11-18-95

05-16-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

64.38

63.33

63.93

59.70

58.18

56.46

58.07

55.35

55.85

54.57

53.93

49.47

41.70

MS

S

S

S

s

TR

T

S

S

S

S

S

S

PS

10N19W07DBDA01

DATE

09-21-95

11-19-95

02-24-96

05-16-96

WATER

LEVEL

37.67

37.38

35.59

31.48

MS

S

S

S

S

10N19W07DDCD01

DATE

11-02-94

01-18-95

06-06-95

08-18-95

09-20-95

11-17-95

02-24-96

05-16-96

WATER

LEVEL

35.25

38.63

36.15

33.76

33.04

33.33

29.50

26.47

MS

S

S

S

S

s

s

SR

S

10N19W07DDDC01

DATE

11-02-94

01-18-95

04-05-95

06-06-95

08-19-95

09-18-95

11-17-95

02-24-96

05-16-96

WATER

LEVEL

42.12

44.36

43.64

41.29

39.39

38.86

38.99

35.19

32.17

MS

S

S

S

s

s

s

s

s

s

10N19W08ABBC01*

DATE

08-03-94

10-31-94

01-18-95

04-05-95

06-03-95

08-18-95

09-20-95

11-18-95

02-24-96

05-15-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

WATER

LEVEL

30.60

36.52

33.17

37.34

28.66

28.72

31.24

31.84

34.80

35.40

26.46

26.53

29.41

35.55

31.67

MS

S

S

s

s

s

s

s

s

s

s

T

T

S

SR

S

10N19W08ABBC01* cont. 10N19W08BCAD01*cont.

DATE

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

28.18

21.19

21.12

22.56

28.48

MS

s

s

s

s

s

10N19W08ADAD01

DATE

10-25-94

01-14-95

03-26-95

06-03-95

08-15-95

09-20-95

11-18-95

02-23-96

05-15-96

WATER

LEVEL

103.56

89.95

86.92

102.81

108.19

100.82

91.93

93.78

86.11

MS

s

s

s

s

SR

S

S

SR

SR

10N19W08ADDC01

DATE

10-25-94

01-18-95

04-03-95

06-03-95

08-15-95

09-12-95

11-18-95

02-26-96

05-17-96

WATER

LEVEL

117.44

100.63

92.15

115.97

113.36

110.65

100.52

101.14

98.31

MS

SR

S

S

SR

S

T

S

SR

SR

10N19W08BADD01

DATE

10-31-94

01-16-95

03-27-95

06-04-95

08-15-95

09-22-95

11-17-95

02-23-96

05-15-96

WATER

LEVEL

237.01

237.26

237.13

237.21

238.92

237.26

236.79

235.95

235.75

MS

S

S

S

S

s

s

s

s

s

10N19W08BBDD01

DATE

01-18-95

06-05-95

08-15-95

09-20-95

05-17-96

WATER

LEVEL

203.48

203.70

205.41

204.02

202.51

MS

S

S

S

s

s

10N19W08BCAD01*

DATE

08-15-94

10-31-94

01-18-95

04-05-95

06-06-95

08-15-95

09-13-95

11-18-95

WATER

LEVEL

200.02

197.42

196.78

196.85

196.68

200.40

198.07

196.85

MS

s

s

s

s

s

s

T

s

DATE

02-26-96

05-15-96

07-25-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

196.57

195.98

204.27

197.74

198.02

199.83

199.90

195.68

204.99

204.99

201.16

MS

s

SR

TR

T

S

S

s

s

ps

s

s

10N19W08BCBB01

DATE

10-27-94

01-16-95

03-26-95

06-05-95

08-16-95

09-22-95

11-18-95

02-24-96

05-15-96

WATER

LEVEL

145.18

144.38

144.93

144.40

145.75

145.57

144.77

147.08

142.82

MS

S

s

s

s

s

s

s

s

s

10N19W08BCCC01

DATE

10-31-94

01-19-95

03-31-95

06-05-95

08-17-95

09-20-95

11-19-95

02-23-96

05-15-96

WATER

LEVEL

129.60

130.22

130.10

130.40

130.45

130.35

128.79

126.82

125.98

MS

S

s

s

s

s

s

s

s

s

10N19W08BDAB01

DATE

10-30-94

01-16-95

03-27-95

06-05-95

08-15-95

09-22-95

11-17-95

02-24-96

05-17-96

WATER

LEVEL

228.10

227.77

227.29

227.26

229.19

227.42

227.08

227.32

226.32

MS

SR

S

S

S

S

s

s

SR

S

10N19W08CBDD01*

DATE

08-23-94

10-31-94

01-18-95

03-27-95

06-06-95

08-16-95

09-22-95

11-17-95

02-25-96

05-16-96

07-25-96

WATER

LEVEL

51.75

56.08

57.68

55.83

52.30

49.79

49.48

51.01

47.73

45.67

43.72

MS

S

S

s

s

s

s

s

s

s

s

T

TABLE 5 57
Table 5. Records of water levels in wells (Continued) 

1QN19W08CBDDQ1* cont.

DATE

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

43.95

46.88

44.54

43.53

43.47

42.52

35.81

32.00

34.95

MS

T

S

S

S

S

S

S

S

S

10N19W08CDAC01

DATE

10-31-94

01-19-95

03-27-95

06-06-95

08-16-95

09-13-95

11-17-95

02-25-96

05-17-96

WATER

LEVEL

77.50

79.02

78.91

77.99

72.99

73.48

74.39

72.48

71.48

MS

S

S

S

S

S

S

S

S

S

10N19W08DAAC01

DATE

11-02-94

01-18-95

03-27-95

06-04-95

08-17-95

09-22-95

11-17-95

02-25-96

05-16-96

WATER

LEVEL

71.58

68.05

66.96

77.19

73.15

73.04

68.53

65.83

65.46

MS

S

SR

S

S

S

S

S

S

S

10N19W08DBBD01

DATE

08-15-95

11-17-95

02-26-96

05-17-96

WATER

LEVEL

199.75

198.23

198.77

196.68

MS

S

S

S

S

10N19W08DCCB01*

DATE

08-19-95

11-17-95

02-23-96

05-16-96

07-25-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

115.90

115.69

117.79

114.14

113.03

112.33

111.94

112.18

111.73

111.78

110.79

107.97

106.55

107.01

MS

S

S

S

S

T

T

S

S

S

S

S

S

S

S

10N19WQ8DCCC01 1QN19W17BAAAQ1 cont.

DATE

08-19-94

10-31-94

01-16-95

WATER

LEVEL

136.80

136.73

137.81

MS

-

S

S

10N19W08DCCC02

DATE

08-26-93

12-06-93

03-10-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

150.52

141.15

140.82

140.84

141.84

143.32

143.05

141.87

140.19

139.97

138.39

136.82

135.56

135.35

133.94

128.30

MS

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

10N19W09BCCC01*

DATE

01-14-95

03-26-95

06-03-95

08-17-95

11-17-95

02-24-96

05-16-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

51.59

49.13

79.13

77.78

56.95

48.87

47.25

57.21

59.03

54.77

48.94

47.97

36.71

60.69

53.22

81.95

52.34

MS

S

S

S

S

SR

S

S

TR

T

S

S

S

S

S

S

S

S

10N19W16BBBC01

DATE

10-31-94

01-14-95

03-27-95

06-06-95

08-16-95

09-15-95

11-18-95

02-25-96

05-16-96

WATER

LEVEL

204.12

204.10

205.04

204.44

204.73

204.56

203.84

203.62

201.76

MS

s

S

s

s

s

SR

S

SR

S

10N19W17BAAA01

DATE

10-31-94

01-14-95

03-27-95

06-06-95

08-16-95

WATER

LEVEL

121.44

122.96

123.18

121.20

119.81

MS

S

s

s

s

s

DATE

09-21-95

11-17-95

02-23-96

05-18-96

WATER

LEVEL

119.64

119.35

117.03

115.44

MS

S

S

S

S

10N19W17BBDA01

DATE

11-02-94

01-16-95

03-27-95

06-06-95

08-16-95

09-18-95

11-17-95

02-25-96

05-17-96

WATER

LEVEL

93.22

94.99

94.29

91.64

90.45

90.84

90.62

88.01

84.89

MS

S

S

S

S

S

SR

SR

SR

S

10N19W17BCAB01

DATE

11-02-94

01-16-95

03-27-95

06-06-95

08-17-95

09-18-95

11-17-95

WATER

LEVEL

90.49

91.71

89.54

89.54

88.37

88.40

84.35

MS

S

S

S

S

S

S

SR

10N19W17BCCC01

DATE

08-19-95

09-18-95

11-17-95

02-24-96

05-17-96

WATER

LEVEL

94.95

94.18

93.95

91.86

88.74

MS

S

S

S

SR

S

10N19W18AAAA01

DATE

08-24-94

11-02-94

01-19-95

03-26-95

06-06-95

WATER

LEVEL

45.23

46.45

48.53

48.03

45.17

MS

S

S

S

S

S

10N19W18AADB01*

DATE

08-16-95

09-13-95

11-17-95

02-25-96

05-16-96

07-25-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

42.98

42.58

42.91

39.36

35.28

40.94

36.18

37.17

37.79

34.31

33.38

38.69

29.48

35.73

31.23

MS

SR

T

S

S

S

TR

T

S

S

S

S

S

S

S

S

58 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 5. Records of water levels in wells (Continued) 

10N19W18ABAD01

DATE

08-16-95

09-18-95

11-17-95

02-23-96

05-16-96

WATER

LEVEL

30.30

29.68

30.28

26.09

22.67

MS

S

S

S

S

S

10N19W18ADDC01*

DATE

01-21-95

06-06-95

08-22-95

09-18-95

11-17-95

02-26-96

05-17-96

07-25-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

85.66

87.59

81.84

81.37

81.93

78.86

75.65

76.27

76.86

79.47

78.86

75.65

74.33

73.85

70.58

71.38

74.32

MS

S

S

S

S

S

SR

S

T

T

S

S

S

S

S

S

S

S

10N19W18DBBAOI

DATE

01-21-95

06-08-95

08-22-95

09-13-95

11-19-95

02-26-96

05-17-96

WATER

LEVEL

71.09

70.74

67.77

67.45

68.82

67.36

64.40

MS

S

S

S

T

S

S

S

09N20W20ACAD01

DATE

08-22-95

09-28-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

27.26

25.17

27.39

24.57

24.83

22.70

22.25

22.96

20.69

MS

R

R

R

R

R

R

R

R

R

09N20W26BACC02

DATE

08-26.93

12-07-93

03-09-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-03-96

WATER

LEVEL

80.08

81.45

60.76

79.65

80.80

80.52

80.31

79.02

79.68

79.14

79.68

79.54

MS

R

R

R

R

R

R

R

R

R

R

R

T

09N20W26BACC02 cont. 08N2QW19BAAD03 cont.

DATE

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL MS

78.80 R

78.17 R

79.91 R

78.45 R

79.70 R

08N21W27DCBC01

DATE

08-26-93

12-07-93

03-13-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-03-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL MS

6.56 R

11.70 R

11.88 R

2.75 R

13.65 R

12.95 R

10.80 R

2.39 R

8.46 R

7.11 R

4.36 R

4.66 T

2.47 R

8.08 R

11.53 R

1.78 R

8.62 R

08N20W12BAAA01*

DATE

10-10-95

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL MS

54.99 S

46.46 S

47.73 S

45.18 S

51.46 S

45.32 S

42.29 S

40.77 S

40.47 S

08N20W19BAAD03

DATE

07-03-57

08-13-57

09-05-57

11-06-57

12-06-57

01-02-58

02-11-58

03-07-58

04-01-58

05-06-58

06-17-58

07-03-58

08-05-58

09-03-58

00-02-58

01-03-58

02-09-58

01-02-59

02-06-59

03-05-59

04-01-59

04-10-59

05-10-59

06-05-59

07-10-59

WATER

LEVEL MS

14.64

14.98

15.50

15.64

16.04

16.32

16.54

16.21

16.35

14.81

14.27

14.01

14.26

14.68

14.53

15.13

15.11

15.30

16.22

16.29

16.49

16.14

14.28

13.52

13.76

WATER

DATE

08-05-59

09-16-59

00-05-59

01-20-59

02-10-59

01-10-60

02-10-60

03-16-60

04-08-60

05-24-60

06-06-60

07-07-60

08-02-60

09-01-60

10-10-60

11-16-60

12-18-60

01-02-61

02-06-61

03-03-61

04-02-61

05-02-61

06-06-61

07-07-61

08-13-61

09-02-61

10-09-61

11-22-61

12-30-61

03-02-62

08-27-62

03-04-63

09-06-63

03-13-64

03-05-65

09-03-65

03-08-66

09-07-66

11-30-66

03-06-67

06-05-67

09-11-67

11-30-67

03-07-68

05-28-68

08-21-68

12-11-68

06-10-69

09-04-69

12-17-69

03-11-70

06-24-70

09-10-70

11-12-70

02-17-71

06-02-71

09-13-71

12-21-71

03-13-72

06-26-72

09-20-72

03-29-73

06-21-73

12-03-73

03-19-74

06-27-74

10-09-74

01-14-75

04-15-75

06-30-75

08-26-75

11-24-75

02-10-76

LEVEL

13.76

12.74

13.65

14.70

15.07

15.95

16.37

17.03

16.58

13.03

13.54

12.97

12.91

13.61

14.13

14.16

15.42

15.61

16.15

15.84

16.28

13.93

13.23

12.69

12.88

12.39

13.15

14.68

15.06

16.86

14.12

15.60

13.92

16.47

16.20

14.65

18.03

15.32

15.90

16.87

14.35

15.08

15.70

16.70

14.56

14.48

16.36

14.48

15.58

17.21

18.09

15.14

14.71

16.01

17.07

14.52

15.07

16.52

16.67

16.23

16.34

19.76

15.87

17.71

18.86

16.48

16.87

19.02

18.19

16.14

15.90

17.86

19.22

MS

TABLE 5 59
Table 5. Records of water levels in wells (Continued) 

08N20W19BAAD03 cont.

DATE

05-26-76

08-29-76

11-10-76

02-14-77

06-20-77

09-21-77

12-20-77

02-15-78

05-10-78

08-23-78

11-29-78

02-21-79

05-21-79

09-19-79

03-11-80

06-10-80

07-14-81

05-18-82

08-24-82

10-12-83

10-11-84

10-30-86

10-25-89

09-13-90

04-25-91

09-17-91

09-09-92

03-10-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-04-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

16.12

16.67

17.00

19.69

16.26

16.58

17.19

18.67

17.01

16.29

17.68

18.18

15.71

15.71

17.38

14.20

15.10

15.78

14.36

14.58

15.09

14.86

14.80

14.42

16.12

14.34

14.78

16.62

14.07

15.15

15.63

17.02

13.57

13.25

14.10

14.61

14.99

13.39

13.92

14.55

13.50

13.68

MS

-

-

-.

..

-

_

-

..

-

-

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

R

R

R

R

R

R

R

R

R

T

R

R

R

R

R

08N20W26BAAC01

DATE

08-26-93

12-07-93

03-10-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

09-04-97

WATER

LEVEL

189.26

179.82

180.41

186.26

189.83

182.76

181.69

182.01

179.91

180.49

180.59

185.70

177.69

180.85

202.81

MS

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

08N20W30CDAB01

DATE

08-26-93

12-07-93

03-09-94

06-16-94

WATER

LEVEL

16.05

18.25

22.30

16.35

MS

R

R

R

R

08N20W30CDAB01 cont.

DATE

09-27-94

12-20-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

19.09

22.62

26.06

18.58

16.58

18.01

19.17

16.14

15.94

18.89

15.46

15.08

MS

R

R

R

R

R

R

R

R

R

R

R

R

08N19W04BDAA01

DATE

08-26-93

12-07-93

03-09-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

18.61

17.63

22.10

14.85

22.16

22.25

13.03

13.28

18.01

15.39

17.78

10.65

17.94

19.94

9.72

17.80

MS

R

R

R

R

R

R

R

RR

R

R

R

R

R

R

R

R

08N19W07CBBD01

DATE

04-18-56

05-07-56

06-05-56

07-06-56

08-06-56

09-10-56

10-01-56

11-06-56

12-05-56

03-11-57

04-12-57

04-30-57

06-11-57

07-05-57

08-13-57

09-13-57

10-04-57

11-06-57

12-06-57

01-13-58

02-03-58

03-10-58

04-02-58

05-16-58

05-30-58

06-20-58

06-28-58

07-03-58

07-11-58

07-17-58

07-25-58

08-01-58

08-08-58

WATER

LEVEL

91.76

92.38

93.20

94.16

92.63

89.34

87.68

85.74

83.51

84.65

86.36

87.66

89.80

89.49

88.72

87.50

86.63

85.31

84.44

84.66

84.97

87.08

88.37

90.88

92.03

92.80

92.69

93.05

94.04

94.03

93.27

92.98

92.47

MS

-

_

_

-

-

-

-

-

-

-

-

-.

_

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

08N19W07CBBD01 cont. 

WATER

DATE

08-15-58

08-22-58

08-29-58

09-05-58

09-12-58

09-19-58

09-26-58

10-03-58

10-10-58

10-17-58

10-24-58

10-31-58

11-07-58

11-14-58

11-24-58

11-28-58

12-05-58

12-12-58

12-19-58

12-26-58

01-02-59

01-09-59

01-23-59

01-30-59

02-06-59

02-13-59

02-20-59

02-27-59

03-13-59

03-20-59

03-27-59

04-02-59

04-17-59

04-24-59

05-08-59

05-15-59

05-22-59

06-05-59

06-12-59

06-19-59

06-26-59

07-10-59

07-17-59

07-23-59

07-31-59

08-07-59

08-21-59

08-28-59

09-04-59

09-18-59

09-25-59

10-02-59

10-09-59

10-16-59

10-23-59

11-27-59

12-04-59

12-11-59

12-18-59

12-26-59

12-31-59

01-29-60

02-05-60

02-12-60

02-19-60

02-26-60

03-11-60

03-18-60

03-25-60

04-01-60

04-08-60

04-15-60

04-22-60

LEVEL

92.17

91.80

91.06

90.68

89.70

89.57

89.63

89.25

88.85

88.21

88.72

87.70

87.79

87.47

87.00

87.52

88.26

87.17

87.04

87.62

86.92

87.18

87.31

88.48

87.63

88.59

89.30

88.83

91.04

89.88

90.01

90.70

91.47

91.19

92.04

92.37

93.17

93.82

94.06

94.50

94.64

95.49

95.65

95.70

95.83

95.73

94.90

95.01

94.47

93.76

93.38

93.23

92.79

92.92

93.00

91.46

91.33

90.78

90.96

91.14

90.65

91.65

91.77

92.27

92.39

92.62

93.23

93.75

94.35

94.92

94.82

95.23

95.40

MS

..

-

-

-

-

..

-

-

-

-

-P

-

-

-

-

-

_

..

-

..

-

-

-P

-

-

_

-

-P

-P

-

-

-

-.

..

-

-

-

-

_

_

_

_

-

_

_

_

_

_

_

-

-

_

_

-

-

60 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 5. Records of water levels in wells (Continued) 

08N19W07CBBD01 cont.

DATE

05-20-60

05-27-60

06-03-60

06-17-60

06-24-60

07-01-60

07-08-60

07-15-60

07-29-60

08-05-60

09-09-60

10-07-60

11-04-60

12-02-60

02-06-61

03-03-61

03-31-61

05-02-61

06-02-61

07-05-61

08-04-61

03-02-62

08-27-62

03-04-63

09-11-63

03-13-64

11-29-78

02-21-79

05-21-79

09-19-79

03-11-80

06-10-80

10-08-80

01-14-81

04-07-81

07-14-81

01-05-82

05-18-82

08-24-82

10-12-83

10-11-84

10-30-86

10-25-89

09-13-90

09-17-91

09-09-92

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

08-22-95

09-28-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

96.22

97.65

97.94

98.06

98.82

99.32

100.66

100.84

100.06

99.87

98.14

96.15

95.57

93.85

93.89

95.00

96.32

98.38

99.60

100.60

99.86

97.87

102.16

95.87

95.77

91.87

95.09

94.56

99.80

97.66

95.24

100.65

95.49

88.53

90.97

96.82

84.35

89.87

88.45

79.25

80.79

93.68

101.40

99.15

99.30

104.14

105.91

101.81

101.39

101.34

106.88

107.04

102.45

98.17

97.14

99.97

90.60

82.27

83.33

76.49

MS

-

-

-

-P

_

_

_

_

-

-

_

-

-

_

-

-

-

..

..

-

-

..

-

-

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

R

R

R

R

R

S

R

R

R

R

R

R

R

R

07N21W36DDDC01

DATE

08-27-93

12-07-93

03-09-94

06-16-94

09-27-94

12-20-94

03-23-95

WATER

LEVEL

9.05

12.01

12.53

8.46

12.30

12.28

12.75

MS

R

R

R

R

R

R

R

07N21W36DDDC01 cont. Q7N2QW34CCCD01

DATE

06-27-95 

09-28-95 

12-19-95 

03-14-96 

06-18-96

WATER 

LEVEL

8.78

12.40

12.52

13.04

7.74

Q7N20W32DDDA02

MS

R

R

R

R

R

DATE

06-26-72

09-20-72

12-20-72

03-29-73

06-21-73

09-18-73

12-03-73

03-19-74

06-27-74

10-10-74

01-14-75

04-15-75

06-30-75

08-26-75

11-24-75

02-10-76

05-26-76

08-29-76

11-10-76

02-14-77

06-20-77

09-21-77

12-20-77

05-10-78

08-23-78

11-29-78

02-21-79

05-21-79

09-19-79

03-11-80

06-10-80

10-07-80

01-14-81

04-07-81

07-14-81

01-05-82

05-18-82

08-24-82

07-23-91

08-25-93

12-07-93

03-09-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

08-21-95

09-28-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

5.94

5.10

9.40

11.79

5.53

5.13

8.52

11.53

5.76

6.39

10.54

12.33

5.93

5.01

8.44

11.41

8.24

4.94

8.19

11.56

5.54

4.93

9.68

10.72

4.03

9.48

11.52

8.28

5.90

11.68

7.92

6.48

10.91

13.21

6.14

9.46

11.05

5.41

7.03

4.16

8.47

12.20

7.04

5.99

10.10

12.75

6.62

5.85

5.37

8.97

11.12

7.44

5.49

9.40

6.51

4.67

MS

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

R

R

R

R

R

R

R

R

S

R

R

R

R

R

R

R

R

DATE

08-23-95

11-10-95

WATER

LEVEL MS

10.33 S

13.38 S

07N20W34CDDB01*

DATE

08-24-95

11-10-95

02-21-96

04-02-96

05-15-96

07-23-96

09-23-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL MS

21.14 SR

22.23 S

28.17 S

30.26 S

31.70 TR

20.56 T

18.09 T

23.13 S

24.34 S

27.50 S

29.13 S

32.39 S

22.81 S

28.57 S

19.94 S

06N21W01CBAB02*

DATE

04-19-95

05-26-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL MS

38.13 S

37.81 S

38.15 S

37.79 S

38.05 S

38.08 T

37.73 T

38.17 T

39.29 S

38.01 S

38.35 S

38.53 S

38.12 S

38.09 S

38.32 S

38.41 S

06N21W02ABBD01*

DATE

08-25-93

12-07-93

03-09-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-28-95

12-19-95

02-23-96

03-13-96

04-02-96

05-14-96

06-18-96

07-24-96

09-23-96

09-24-96

11-18-96

12-19-96

01-06-97

02-25-97

04-02-97

WATER

LEVEL MS

38.83 R

49.10 R

53.40 R

43.62 R

47.02 R

52.54 R

54.90 R

39.58 R

42.76 R

42.18 R

57.14 SR

50.89 R

56.38 S

56.21 T

45.58 R

46.41 S

48.64 S

44.81 R

53.56 S

52.03 R

54.76 S

58.11 S

PTABLE 5 61
Table 5. Records of water levels in wells (Continued)

06N21W02ABBD01* cont. 06N21W03DDAA01* cont. 06N21W11CBDCOI* cont.

DATE

05-19-97

06-17-97

06-23-97

08-18-97

09-04-97

10-14-97

WATER

LEVEL

53.56

44.39

47.16

45.37

41.98

50.75

MS

S

R

S

S

R

S

06N21W03ACBA01

DATE

05-26-95

08-11-95

10-20-95

WATER

LEVEL

22.80

25.20

16.55

MS

S

S

S

06N21W03CAAC01*

DATE

04-20-95

05-26-95

08-11-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

10.26

5.95

9.31

12.09

8.57

11.67

7.56

7.47

11.58

12.78

5.74

10.07

10.12

8.22

8.46

6.41

12.25

MS

S

S

SR

S

S

S

T

T

T

S

S

S

S

S

S

S

S

06N21W03CDAC01

DATE

08-25-93

12-07-93

03-09-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

34.62

34.95

35.39

34.77

35.74

35.69

35.63

34.82

35.01

34.87

34.02

34.57

33.91

35.32

34.59

34.77

MS

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

06N21W03DDAA01*

DATE

04-20-95

05-26-95

08-11-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

WATER

LEVEL

18.13

16.68

6.87

15.11

6.25

8.66

9.31

12.85

MS

S

S

S

SR

S

S

T

T

DATE

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL MS

14.96 T

19.86 S

18.10 S

11.88 S

6.54 S

16.58 S

8.01 S

11.23 S

16.35 S

06N21W10BDDD01

DATE

05-26-95

08-11-95

10-20-95

WATER

LEVEL MS

44.33 S

42.89 SR

45.75 SR

06N21W11CAAA01*

DATE

04-18-95

05-26-95

08-11-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL MS

6.36 S

3.92 S

3.84 S

4.06 S

2.30 S

3.70 S

2.49 T

3.25 T

3.75 T

3.96 S

2.05 S

4.68 S

3.01 S

2.23 S

2.41 S

2.98 S

5.36 S

06N21W11CBCA01*

DATE

04-19-95

05-26-95

08-11-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL MS

15.39 S

9.13 S

11.86 S

14.03 S

13.89 S

12.78 S

14.54 T

12.58 T

12.98 T

13.62 S

12.75 S

14.53 S

14.28 S

15.40 S

13.11 S

12.88 S

13.53 S

06N21W11CBDC01*

DATE

04-19-95

05-26-95

08-11-95

10-20-95

WATER

LEVEL MS

37.97 S

38.10 S

41.65 SR

32.10 S

DATE

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

36.82

38.47

34.29

30.35

61.40

36.28

36.37

44.53

37.11

36.13

30.07

31.62

40.19

MS

SR

S

T

T

TR

S

S

S

S

S

S

S

S

06N21W11CDCB01

DATE

08-11-95

10-20-95

WATER

LEVEL

14.62

14.40

MS

S

S

06N21W13BBAB01*

DATE

04-18-95

05-26-95

08-11-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

81.73

78.28

67.99

66.68

76.17

77.62

77.50

70.79

67.80

70.38

74.66

77.09

79.39

79.06

76.72

64.77

67.87

MS

S

S

S

S

S

S

T

T

T

S

S

S

S

S

S

S

S

06N21W14BDAC01*

DATE

10-26-94

01-26-95

03-31-95

05-24-95

08-11-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

19.39

27.47

20.66

16.60

12.22

13.39

24.67

20.96

19.89

16.89

15.33

16.19

19.53

25.28

21.59

19.40

17.00

12.42

13.23

MS

S

S

S

S

S

S

S

S

T

TR

T

S

S

S

S

S

S

S

S

62 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 5. Records of water levels in wells (Continued) 

06N21W15ABBB01

DATE

05-26-95

08-11-95

10-20-95

WATER

LEVEL

111.33

108.46

89.85

MS

S

SS

SS

06N21W15ADBC01*

DATE

06-12-95

08-11-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

133.93

138.15

135.60

134.49

136.09

135.69

144.35

131.08

136.02

136.57

134.70

132.04

126.43

124.88

131.60

146.60

MS

S

SR

SR

S

S

TR

TR

T

S

S

S

S

S

S

S

S

06N21W15CDDD01*

DATE

10-26-94

01-26-95

03-31-95

05-24-95

08-11-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-26-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

58.08

67.65

68.58

60.32

45.14

44.87

63.89

64.33

60.77

41.48

45.16

51.91

62.31

65.87

64.92

53.37

43.11

46.31

47.04

MS

S

S

S

S

S

S

S

S

T

T

T

S

S

S

S

S

S

S

S

06N21W21ADDB01*

DATE

10-25-94

01-25-95

03-30-95

05-23-95

08-10-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

130.69

133.41

135.27

136.52

! 33.97

129.19

133.03

135.70

133.65

134.01

128.87

127.67

130.29

131.91

133.25

133.74

133.29

129.62

124.77

MS

S

S

S

S

S

S

S

SR

S

T

S

S

S

S

S

S

S

S

S

06N21W22BCCA01 06N21W23DDAD01

DATE

01-25-95

03-30-95

05-24-95

08-10-95

10-20-95

WATER

LEVEL

98.96

101.83

103.28

94.23

91.49

MS

SR

S

S

S

S

06N21W23CABC01*

DATE

06-12-95

08-10-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

101.99

102.48

102.25

101.68

103.12

102.32

108.80

103.95

106.49

101.71

102.38

102.22

100.80

101.28

103.19

103.00

MS

S

SR

S

S

S

T

TP

T

SR

S

S

S

S

S

S

S

06N21W23CBCB01

DATE

01-25-95

03-30-95

05-24-95

08-10-95

10-20-95

WATER

LEVEL

96.59

97.04

97.47

94.82

94.92

MS

S

S

S

S

S

06N21W23CDCB01

DATE

01-25-95

03-30-95

05-23-95

08-10-95

10-20-95

WATER

LEVEL

51.76

53.23

48.40

44.45

48.52

MS

S

SR

S

S

SR

06N21W23DADA01

DATE

01-25-95

03-30-95

05-24-95

08-08-95

10-20-95

WATER

LEVEL

17.17

17.24

5.89

3.05

5.22

MS

S

S

S

S

S

06N21W23DADD01

DATE

01-26-95

03-30-95

05-24-95

08-08-95

10-20-95

WATER

LEVEL

16.04

16.17

13.25

4.89

6.78

MS

S

S

S

S

S

DATE

08-08-95

10-20-95

WATER

LEVEL MS

6.10 S

8.14 S

06N21W23DDBB01*

DATE

08-31-94

01-25-95

03-30-95

05-24-95

08-08-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL MS

5.52 S

9.81 S

9.86 S

6.23 S

3.85 S

4.69 S

5.68 S

8.02 S

8.33 T

3.44 T

5.65 T

7.94 S

2.91 T

7.22 S

8.12 S

6.55 S

3.84 S

4.26 S

5.53 S

06N21W23DDCB01

DATE

01-25-95

03-30-95

05-24-95

08-08-95

10-20-95

WATER

LEVEL MS

6.55 S

6.99 S

5.55 S

3.22 S

3.52 SR

06N21W23DDDA01

DATE

01-25-95

03-30-95

05-24-95

08-08-95

10-20-95

WATER

LEVEL MS

9.48 S

9.75 S

7.82 S

3.44 S

4.38 S

06N21W24BAAC01*

DATE

10-25-94

01-25-95

03-31-95

05-24-95

08-11-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL MS

17.77 S

18.65 S

18.97 S

18.07 S

17.86 S

17.71 S

18.41 SR

19.69 SR

18.63 T

17.68 T

17.95 T

18.01 S

16.68 S

18.41 S

18.90 S

17.83 S

20.02 S

17.83 S

17.83 S

TABLE 5 63
Table 5. Records of water levels in wells (Continued) 

06N21W24BDCC01

DATE

05-26-95

08-11-95

10-20-95

WATER

LEVEL

58.28

58.18

54.92

MS

s

s

s

06N21W24CCAC01*

DATE

08-31-94

01-25-95

03-30-95

05-24-95

08-08-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

21.11

25.88

26.50

27.65

19.29

20.83

22.33

23.76

24.18

19.57

22.39

23.57

20.09

20.67

23.62

23.91

19.84

20.63

22.65

MS

s

s

s

s

s

s

s

s

T

T

T

S

S

S

S

S

S

S

S

06N21W24CCBB02

DATE

01-25-95

03-30-95

05-24-95

08-08-95

10-20-95

WATER

LEVEL

15.56

15.78

16.33

7.37

7.41

MS

S

s

ss

ss

s

06N21W26AADD01

DATE

01-26-95

03-30-95

05-24-95

08-10-95

10-20-95

WATER

LEVEL

38.89

37.98

36.26

36.67

35.98

MS

S

s

s

s

s

06N21W26ABAD01*

DATE

08-18-94

01-25-95

03-31-95

05-24-95

08-10-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

37.14

38.98

40.54

36.46

36.53

36.58

37.59

38.43

37.01

36.11

38.84

37.06

36.39

45.04

36.99

39.84

MS

s

s

s

s

s

s

s

s

T

T

S

s

s

s

s

s

Q6N21W26BBCA01 06N21W27ADBC01*

DATE

01-25-95

03-30-95

05-23-95

08-10-95

10-20-95

WATER

LEVEL

36.85

37.32

37.68

32.74

34.54

MS

S

S

s

s

s

06N21W26CBAB01

DATE

01-25-95

03-30-95

05-23-95

08-09-95

10-20-95

WATER

LEVEL

17.49

15.68

16.29

14.73

15.14

MS

s

s

SR

SR

S

06N21W26DBAD01*

DATE

08-25-93

12-07-93

03-08-94

06-16-94

09-13-94

09-27-94

12-20-94

01-25-95

03-23-95

03-30-95

05-23-95

06-27-95

08-09-95

09-27-95

10-20-95

12-19-95

02-21-96

03-14-96

04-02-96

05-14-96

06-18-96

07-23-96

09-23-96

09-24-96

11-18-96

12-19-96

01-06-97

02-25-97

04-02-97

05-19-97

06-17-97

06-23-97

08-18-97

09-04-97

10-14-97

WATER

LEVEL

30.35

32.27

33.68

32.75

32.52

32.93

34.38

34.51

34.25

34.37

33.60

32.52

32.48

32.18

32.60

31.37

30.13

31.10

31.49

31.46

30.61

31.63

31.64

32.57

36.21

33.50

31.45

31.21

32.16

31.87

30.54

30.93

31.82

32.20

32.95

MS

R

R

R

R

S

R

R

S

R

S

S

R

S

R

S

R

S

R

S

S

R

S

S

R

S

R

T

S

S

S

R

S

S

R

S

06N21W26DBDD01

DATE

01-25-95

03-30-95

05-23-95

08-09-95

10-20-95

WATER

LEVEL

38.08

38.02

38.28

39.11

37.74

MS

S

S

s

SR

S

DATE

08-29-94

01-25-95

03-30-95

05-24-95

08-10-95

10-20-95

02-21-96

04-02-96

05-14-96

07-23-96

09-23-96

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

WATER

LEVEL

45.04

46.39

48.23

47.52

46.12

44.38

44.25

45.53

44.32

42.47

44.03

44.67

45.05

43.91

43.57

44.55

43.25

43.03

42.71

MS

s

s

sz

s

s

s

s

s

T

T

T

T

T

S

S

S

S

S

S

06N21W27BABA01

DATE

01-25-95

03-30-95

05-23-95

08-10-95

10-20-95

WATER

LEVEL

66.89

66.78

67.65

74.42

66.34

MS

S

S

s

SR

SR

06N21W27BBAA01

DATE

08-25-93

12-07-93

03-08-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-27-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

81.23

81.10

80.76

82.17

83.99

81.80

83.55

81.95

80.95

81.27

86.28

81.64

82.00

80.95

82.13

79.18

MS

R

R

R

R

RP

R

R

R

R

R

R

R

R

R

R

R

06N20W01BABA01

DATE

08-24-95

05-15-96

WATER

LEVEL

8.08

21.77

MS

SR

T

06N20W01BABB01*

DATE

07-26-95

08-24-95

11-10-95

02-21-96

04-02-96

05-15-96

07-23-96

09-23-96

WATER

LEVEL

10.63

9.64

13.20

19.11

28.67

37.35

11.13

8.42

MS

s

s

s

s

SR

TR

T

T

64 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 5. Records of water levels in wells (Continued) 

06N20W01BABB01* cont.

DATE

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

16.43

17.61

19.17

29.85

15.23

10.85

11.41

MS

S

S

S

S

S

S

S

06N20W01CDCD01*

DATE

06-14-95

08-23-95

11-10-95

02-22-96

04-03-96

05-15-96

07-24-96

09-23-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

5.49

4.05

4.55

8.31

8.42

5.99

3.88

3.11

5.72

7.87

7.84

3.52

4.31

3.96

4.26

MS

S

S

s

SR

S

T

T

T

S

S

S

S ^

S

s

s

06N20W02AADC01

DATE

08-23-95

11-10-95

WATER

LEVEL

33.87

45.25

MS

S

s

06N20W02BBDA01

DATE

08-23-95

11-10-95

WATER

LEVEL

3.64

7.93

MS

S

S

06N20W02DCDC01*

DATE

07-12-95

08-23-95

11-10-95

02-22-96

04-02-96

05-15-96

07-24-96

09-23-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

5.90

7.09

8.23

7.62

7.85

7.99

8.25

8.13

14.52

6.76

8.26

7.84

8.06

7.61

6.77

7.14

MS

S

S

S

S

S

T

T

T

S

S

S

S

S

S

S

S

06N20W03BDBB01

DATE

08-23-95

11-10-95

WATER

LEVEL

17.43

17.52

MS

S

S

06N20W03BDCC01 06N20W04DCCB01*

DATE

08-25-93

12-07-93

03-09-94

06-16-94

WATER

LEVEL

22.93

19.40

32.77

30.56

MS

R

R

R

R

06N20W03BDCC01

DATE

09-27-94

12-20-94

03-23-95

06-27-95

08-24-95

09-28-95

11-11-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

21.97

27.73

32.78

31.91

24.23

21.41

22.61

23.68

29.10

28.69

20.94

25.58

27.03

19.52

MS

R

R

R

RP

S

R

S

R

R

R

R

R

R

R

06N20W04AABC01

DATE

08-24-95

11-10-95

WATER

LEVEL

3.96

7.26

MS

S

S

06N20W04ACCD01

DATE

08-24-95

11-10-95

WATER

LEVEL

32.13

34.02

MS

S

S

06N20W04ADCD01*

DATE

06-14-95

02-22-96

04-02-96

05-15-96

07-23-96

09-23-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

24.93

23.74

25.14

25.89

20.66

18.87

21.13

21.99

23.57

24.84

26.27

19.82

19.64

21.03

MS

S

S

S

T

T

T

S

S

S

S

S

S

S

S

06N20W04CCCD01

DATE

08-24-95

11-10-95

WATER

LEVEL

15.91

19.67

MS

S

S

DATE

06-15-95

08-24-95

11-10-95

02-21-96

04-02-96

05-15-96

07-23-96

09-23-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

36.94

33.09

35.00

38.00

38.05

39.49

33.30

32.76

35.56

36.64

37.73

38.62

38.97

34.03

33.43

33.55

MS

S

S

S

S

S

TR

T

T

S

S

S

S

S

S

S

S

06N20W09BDDD01

DATE

08-24-95

11-10-95

WATER

LEVEL

49.07

49.44

MS

S

S

06N20W09CBCC01*

DATE

08-03-95

08-24-95

11-10-95

02-21-96

04-02-96

05-15-96

07-23-96

09-23-96

11-19-96

01-07-97

02-26-97

04-02-97

05-20-97

06-24-97

08-19-97

10-14-97

WATER

LEVEL

55.81

54.49

60.35

63.83

65.99

63.89

59.18

55.26

60.92

62.44

63.64

64.39

65.02

60.91

56.84

57.75

MS

s

s

SR

s

s

T

TR

T

S

S

s

s

s

s

s

s

06N20W09CCDB01

DATE

08-24-95

11-10-95

WATER

LEVEL

62.56

67.74

MS

s

s

06N20W09DCAB01

DATE

08-24-95

11-10-95

WATER

LEVEL

35.87

36.00

MS

S

S

06N20W10AADC01*

DATE

07-12-95

11-10-95

02-21-96

04-02-96

05-15-96

07-23-96

09-23-96

WATER

LEVEL

21.84

27.80

32.86

36.84

32.82

21.96

15.86

MS

S

S

S

SR

T

T

T

TABLE 5 65
Table 5. Records of water levels in wells (Continued) 

06N20W10AADCQ1* cont.

DATE

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-14-97

WATER

LEVEL

28.32

32.38

29.50

30.87

30.03

27.24

21.56

22.67

MS

s

s

s

s

s

s

s

s

06N20W10ABDB01

DATE

08-24-95

11-10-95

WATER

LEVEL

11.58

15.68

MS

s

s

06N20W10CACB01*

DATE

06-14-95

08-24-95

11-10-95

02-21-96

04-02-96

05-15-96

07-23-96

09-23-96

11-19-96

01-07-97

02-26-97

04-02-97

05-20-97

06-24-97

08-19-97

10-14-97

WATER

LEVEL

140.00

139.25

137.32

137.06

138.19

138.57

138.63

137.24

136.99

138.11

137.32

138.19

140.48

139.76

141.51

140.26

MS

s

s

s

s

s

s

s

s

s

s

s

s

s

s

s

s

06N20W10DBBB01

DATE

08-24-95

11-10-95

WATER

LEVEL

13.28

18.22

MS

s

s

06N20W10DCAB01

DATE

08-24-95

11-10-95

WATER

LEVEL

17.87

22.24

MS

s

s

06N20W12CCCD01*

DATE

05-04-95

08-23-95

11-10-95

02-22-96

04-02-96

05-15-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

38.58

23.10

29.54

32.86

33.67

35.36

23.17

24.73

29.95

32.09

32.34

33.81

34.96

25.18

21.23

27.30

MS

SR

s

s

s

s

TR

T

T

S

s

s

s

s

s

s

s

06N20W14ACDD01* Q6N20W14DAAA01* cont.

DATE

02-22-96

04-02-96

05-15-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

67.99

66.45

69.70

67.23

64.90

67.58

67.19

67.35

68.13

68.98

66.82

66.86

66.00

MS

SR

S

T

T

T

S

S

S

S

S

S

S

S

06N20W14BADB01*

DATE

05-02-95

08-23-95

11-10-95

02-22-96

04-03-96

05-15-96

07-24-96

09-24-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

27.26

11.17

14.21

17.02

19.28

17.15

10.41

11.73

13.20

15.97

16.83

15.32

11.29

10.96

12.67

MS

S

S

SR

S

S

T

T

T

S

S

S

S

S

S

S

06N20W14BBBB01

DATE

08-25-93

12-07-93

03-09-94

06-16-94

03-23-95

06-27-95

09-28-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-17-97

09-04-97

WATER

LEVEL

66.97

66.25

88.57

68.32

68.27

68.68

66.61

66.80

67.78

68.31

66.34

66.60

67.60

66.94

MS

R

R

R

R

R

R

R

R

R

R

R

R

R

R

06N20W14CAAA01

DATE

08-23-95

11-10-95

WATER

LEVEL

8.22

15.56

MS

S

SR

06N20W14DAAA01*

DATE

08-21-95

02-22-96

04-02-96

05-15-96

07-24-96

09-24-96

01-07-97

WATER

LEVEL

94.59

97.68

99.18

99.24

95.89

93.13

96.18

MS

S

SR

S

T

T

T

S

DATE

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL MS

96.67 S

98.04 S

98.82 S

96.06 S

90.67 S

90.15 S

06N20W15AACD01*

DATE

08-24-95

11-10-95

02-21-96

04-03-96

05-15-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL MS

29.99 S

30.62 S

31.80 S

33.00 S

33.01 T

30.90 T

30.50 T

30.30 S

31.69 S

31.25 S

31.86 S

32.64 S

25.93 S

31.71 S

32.96 S

06N20W15BBCC01

DATE

08-23-95

11-10-95

WATER

LEVEL MS

62.29 S

61.15 S

06N20W15CACC01*

DATE

07-25-95

08-23-95

11-10-95

02-22-96

04-03-96

05-15-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL MS

21.35 S

19.88 S

21.73 S

25.10 S

26.12 S

26.91 TR

19.91 T

18.30 T

21.87 SR

22.87 S

22.89 S

26.24 S

25.77 S

19.62 S

24.89 S

24.94 S

06N20W16ACCB01

DATE

08-24-95

11-10-95

WATER

LEVEL MS

71.43 S

74.80 SR

06N20W16ADCB01*

DATE

07-27-95

08-23-95

11-10-95

02-22-96

04-03-96

WATER

LEVEL MS

75.01 S

75.09 S

73.19 S

75.00 SR

75.71 S

66 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 5. Records of water levels in wells (Continued) 

Q6N2QW16ADCB01* cont.

DATE

05-15-96

07-24-96

09-24-96

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

WATER

LEVEL

76.05

76.55

71.52

72.97

74.18

74.47

78.30

79.36

75.86

73.12

72.26

MS

TR

TRTSSSSSSSS

06N20W16BAAD01*

DATE

05-04-95

08-24-95

11-10-95

02-21-96

04-02-96

05-15-96

07-23-96

09-23-96

11-19-96

01-07-97

02-26-97

04-02-97

05-19-97

06-24-97

08-19-97

10-14-97

WATER

LEVEL

92.68

85.74

87.33

90.89

92.73

91.96

86.03

84.16

85.68

89.27

88.39

91.51

91.74

87.36

85.84

88.24

MSSsss

SRTTTSSssssss

06N20W19CCCC02

DATE

09-10-70

09-28-70

10-26-70

11-23-70

12-23-70

01-17-71

01-26-71

02-17-71

02-22-71

03-25-71

04-27-71

05-24-71

06-24-71

07-21-71

08-24-71

09-22-71

10-26-71

11-23-71

12-23-71

01-27-72

02-22-72

03-27-72

04-24-72

05-25-72

06-22-72

07-24-72

08-23-72

09-21-72

10-26-72

11-28-72

12-26-72

01-25-73

02-26-73

03-27-73

WATER

LEVEL

5.78

7.20

10.05

12.09

13.60

15.85

14.28

14.99

15.12

15.77

15.85

8.97

6.06

6.16

6.24

6.35

9.80

11.78

13.20

13.53

14.24

14.22

14.79

10.15

6.18

5.83

5.72

6.58

9.32

11.78

13.04

14.01

15.04

15.89

MS---

..s-ss----

----_-_

.--------

Q6N2QW19CCCCQ2 cont.

DATE

03-29-73

04-26-73

05-25-73

06-26-73

07-24-73

08-27-73

09-18-73

09-26-73

10-24-73

11-27-73

12-03-73

12-20-73

01-28-74

02-25-74

03-19-74

03-25-74

04-24-74

05-29-74

06-19-74

07-24-74

08-26-74

09-25-74

10-23-74

11-20-74

12-20-74

01-22-75

02-24-75

03-25-75

04-23-75

05-21-75

06-21-75

07-28-75

08-22-75

09-24-75

10-28-75

11-21-75

12-22-75

01-22-76

02-23-76

03-24-76

04-20-76

05-24-76

06-21-76

07-22-76

08-20-76

09-23-76

10-21-76

11-18-76

12-22-76

01-24-77

02-22-77

03-28-77

04-26-77

05-25-77

06-21-77

07-26-77

08-23-77

09-20-77

10-20-77

11-17-77

12-20-77

01-20-78

02-15-78

02-22-78

03-23-78

04-24-78

05-10-78

05-24-78

06-26-78

07-20-78

08-23-78

09-21-78

10-19-78

WATER

LEVEL

16.01

16.87

9.59

5.94

5.57

5.88

6.95

7.44

10.48

11.77

12.05

12.85

13.17

13.60

14.27

14.47

15.40

7.57

5.95

6.45

5.41

7.60

9.72

11.80

13.60

15.27

16.20

16.72

17.39

17.42

6.52

5.77

6.01

8.16

10.20

11.82

13.27

14.42

15.54

16.16

16.68

14.66

5.19

5.60

6.03

7.42

10.20

12.40

14.32

15.70

16.60

17.35

17.86

9.74

5.80

5.55

6.00

7.14

9.74

12.28

13.81

14.85

15.68

15.88

16.60

17.12

17.08

13.78

6.51

6.28

6.19

7.01

9.72

Q6N2QW19CCCCQ2 cont. 

WATER

MS DATE

11-28-78

12-19-78

01-25-79

02-21-79

03-27-79

04-25-79

05-24-79

06-25-79

07-25-79

08-29-79

10-11-79

11-20-79

12-20-79

01-16-80

01-22-80

02-26-80

04-08-80

04-21-80

06-06-80

07-24-80

09-03-80

09-23-80

10-16-80

12-02-80

02-26-81

03-05-81

04-14-81

04-21-81

05-20-81

06-24-81

09-16-81

09-22-81

11-04-81

12-16-81

01-27-82

02-26-82

03-08-82

04-20-82

05-28-82

07-13-82

08-24-82

10-07-82

11-16-82

12-28-82

02-08-83

05-04-83

07-07-83

08-02-83

09-13-83

11-03-83

12-14-83

03-13-84

04-24-84

06-06-84

07-17-84

08-28-84

10-10-84

11-27-84

01-17-85

01-23-85

03-01-85

03-06-85

05-22-85

08-15-85

10-01-85

11-14-85

01-09-86

02-19-86

04-10-86

05-29-86

11-19-86

02-18-87

03-24-87

LEVEL

12.85

14.13

15.82

15.67

16.35

16.65

14.38

5.96

6.33

5.52

8.54

12.01

13.67

13.76

14.13

15.43

16.43

16.74

6.52

6.17

6.62

6.84

9.11

12.97

16.45

16.59

17.25

17.34

12.42

6.96

6.61

6.57

10.88

13.36

14.68

15.00

15.07

16.67

8.35

6.69

6.94

7.57

11.55

13.90

15.45

17.81

6.48

5.82

7.27

11.27

13.63

16.68

17.28

7.92

6.75

6.97

8.70

12.58

15.37

15.57

16.44

16.54

14.41

6.35

8.86

12.15

15.19

15.46

16.28

9.80

12.74

16.22

16.81

M----------ss-s-sssss-ss-ss--ss_sss_sssssssssssssssssssssssssss_sssssssss

TABLE 5 67
Table 5. Records of water levels in wells (Continued) 

06N20W19CCCCQ2 cont.

DATE

05-07-87

06-09-87

09-10-87

10-27-87

12-02-87

04-12-88

06-28-88

07-13-88

08-17-88

09-27-88

10-27-88

12-21-88

02-10-89

03-15-89

05-04-89

07-26-89

09-13-89

10-24-89

12-05-89

01-23-90

03-06-90

04-17-90

05-30-90

07-17-90

08-29-90

10-10-90

11-27-90

01-14-91

02-25-91

04-02-91

05-28-91

06-25-91

08-07-91

10-01-91

11-13-91

02-04-92

03-24-92

05-05-92

06-17-92

09-08-92

10-19-92

12-02-92

02-23-93

06-29-93

08-12-93

10-04-93

10-21-93

02-01-94

06-01-94

10-04-94

02-10-95

03-21-95

05-10-95

07-25-95

10-18-95

12-13-95

02-13-96

05-15-96

08-08-96

10-03-96

WATER

LEVEL

16.25

7.37

6.70

10.50

13.20

17.34

6.85

6.47

6.73

7.48

10.72

14.13

16.04

16.26

16.08

6.54

7.06

10.31

13.07

15.40

16.48

17.20

8.22

6.52

6.95

9.12

12.77

15.02

16.34

16.95

10.87

6.53

6.51

7.33

11.59

15.36

16.55

15.99

16.01

7.50

10.10

12.98

15.76

6.90

7.54

9.77

9.77

15.22

8.84

9.80

15.90

16.73

16.47

7.74

9.87

12.09

13.80

15.07

7.08

8.60

MS

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

-

-

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

S

06N20W19CCCCQ2 cont. 05N20W30BDCD01

DATE

11-26-96

01-07-97

WATER

LEVEL

12.58

12.45

MS

S

S

06N20W29BADB01

DATE

08-25-93

12-07-93

03-09-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

09-27-95

12-19-95

03-14-96

06-18-96

09-24-96

12-19-96

06-16-97

09-04-97

WATER

LEVEL

11.87

15.75

18.80

15.03

13.67

17.72

17.75

15.46

13.84

16.81

18.34

15.69

12.54

15.00

13.87

14.10

MS

R

R

RR

R

R

R

R

R

R

R

R

R

R

R

R

R

Q6N19W07BABCQ1* 

WATER

DATE

03-09-94

06-16-94

09-27-94

12-20-94

03-23-95

06-27-95

08-23-95

09-28-95

11-10-95

12-19-95

02-22-96

03-14-96

04-03-96

05-15-96

06-18-96

07-24-96

09-23-96

09-24-96

11-19-96

12-19-96

01-07-97

02-26-97

04-03-97

05-20-97

06-17-97

06-24-97

08-19-97

09-04-97

10-15-97

LEVEL

28.74

23.27

26.17

28.67

29.48

26.65

23.16

26.28

26.45

28.88

31.01

28.50

29.55

26.97

24.38

24.32

25.74

26.36

26.79

27.47

26.44

28.08

28.12

26.09

27.30

23.71

23.95

25.06

27.13

MS

R

R

R

R

R

R

S

R

S

R

SR

R

S

T

R

TR

T

R

S

R

S

S

S

S

R

S

S

R

S

DATE

08-24-93

12-07-93

03-08-94

06-15-94

09-26-94

12-20-94

03-23-95

06-27-95

09-27-95

12-19-95

03-14-96

06-17-96

09-24-96

12-19-96

06-16-97

09-04-97

WATER

LEVEL

21.81

16.80

27.52

20.76

21.96

24.93

21.88

22.37

20.17

22.42

23.59

22.95

22.20

24.44

22.04

22.48

MS

R

R

R

R

R

R

R

RP

R

R

R

R

R

R

R

R

03N21W15CBBB01

DATE

08-24-93

12-07-93

03-08-94

06-15-94

09-26-94

12-20-94

03-22-95

06-26-95

09-27-95

12-19-95

03-13-96

06-17-96

WATER

LEVEL

67.38

70.95

75.45

72.28

68.85

75.43

77.43

72.01

66.41

69.84

71.88

70.61

MS

R

R

R

R

R

R

R

R

R

R

R

R

03N21W15CBBB01

DATE

09-23-96

12-18-96

06-16-97

09-04-97

WATER

LEVEL

65.29

71.78

67.30

63.50

MS

R

R

R

R

02N21W01CACD01

DATE

03-08-94

06-15-94

09-26-94

12-20-94

03-22-95

06-26-95

09-27-95

12-19-95

03-13-96

06-17-96

09-23-96

12-18-96

06-16-97

09-04-97

WATER

LEVEL

25.76

25.20

19.67

25.50

26.96

23.98

18.02

24.00

25.39

26.32

16.64

22.14

17.49

13.06

MS

R

R

R

R

R

R

R

R

R

R

R

R

R

R

68 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
15

20

25

30

10N20W12ACDB01

15

20

25

LU

\JL 30 DC

CO

Q

! 35

10N20W12DADA01

-5

10

10N20W12DDDC01

45

50

55

60

65

70

10N19W06CDDD01

A S O N D 

1994

JFMAMJJASOND 

1995

JFMAMJJASOND 

1996

JFMAMJJASON 

1997

Figure 21. Hydrographs of water levels in wells of the monitoring network.

FIGURE 21 69
100

105

110

115

10N19W06DDCC01

.V

45

50

60

65

10N19W07BAAD01

15

20

25

10N19W07CABD01

A. 

V

I I I I I I I I I I I I I I I I I I 1 I I I I I I I I I I I I I I I I I

20

25

30

35

40

10N19W07CDCC01

\ / 

V

*. .' \ i

\ i

\ i

\ i

\i

ASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASON 

1994 1995 1996 1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

70 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
40

45

50

55

60

65

20

25

10N19W07DABB01

I I I I I

,- so

35

40

10N19W08ABBC01 / >

\ / ' 

hamplota

190

195

200

205

10N19W08BCAD01

\ r"

\ i

V

I I I I A S O N D 

1994

JFMAMJJASOND 

1995

JFMAMJJASOND 

1996

J FMAMJ J ASON 

1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

FIGURE 21 71
30

35

40

50

55

60

- 10N19W08CBDD01 A.

105

110

115

120

: 10N19W08DCCB01

A S O N D 

1994

JFMAMJJASOND 

1995

JFMAMJJASOND 

1996

JFMAMJ JASON 

1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

72 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
35

40

45

50

55

60

65

">

75

80

10N19W09BCCC01

\ /

\ ./

\ /

\ 4

\ /

\ /

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I I I I I I

25

30

35

40

45

10N19W18AADB01

i i i i i i i i i

ASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASON 

1994 1995 1996 1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

FIGURE 21 73
70

75

80

85

90

10N19W18ADDC01

40

45

g 50

if 

cc

55

60

08N20W12BAAA01

m 15

_r 20

25

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07N20W34CDDB01

V /

v

30

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40

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: 06N21W01CBAB02

A S O N D 

1994

JFMAMJJASOND 

1995

JFMAMJJASOND 

1996

JFMAMJ JASON 

1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

74 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
35

40

45

50

55

60

10

15

06N21W02ABBD01

r" \

i i i i i i i i

i i i i r

06N21W03CAAC01 / X f - ,

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v V /

10

15

20

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i i i i i i i r

06N21W03DDAA01

 ' 

10

06N21W11CAAA01

A S O N D 

1994

JFMAMJJASOND 

1995

JFMAMJJASOND 

1996

JFMAMJJASON 

1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

FIGURE 21 75
06N21W11CBCA01

10

15

20

25

30

35

40

45

06N21W11CBDC01

i i i i i i i i i i i i i i

60

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70

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06N21W13BBAB01

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ASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASON 

1994 1995 1996 1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

76 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
10

15

20

25

30

120

125

130

135

140

2 145

06N21W14BDAC01

V

150

40

45

50

55

60

65

70

06N21W15ADBC01

I I I I I I I

06N21W15CDDD01

/ KX

/ > 

/

JL

ASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASON 

1994 1995 1996 1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

FIGURE 21 77
120

125

130

135

140

95

100

105

110

06N21W21ADDB01

06N21W23CABC01

^*-v

10

15

10

15

20

25

[ 06N21W23DDBB01

*

x. /

06N21W24BAAC01

A S O N D 

1994

JFMAMJJASOND 

1995

JFMAMJJASOND 

1996

JFMAMJJASON 

1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

78 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
15

20

25

30

\ II I I I I I I I I I I I I I I I 1 T I T I

06N21W24CCAC01

30

35

40

45

50

06N21W26ABAD01

25

30

35

40

06N21W26DBAD01

 

 .

40

45

50

06N21W27ADBC01

I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I

ASONDJ FMAMJ JASONDJ FMAMJ JASONDJFMAMJ JASON 

1994 1995 1996 1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

FIGURE 21 79
10

15

20

25

06N20W01BABB01

9' \

10

06N20W01CDCD01

I I I I I I I I I I

V-V

06N20W02DCDC01

15

20

25

35

40

06N20W04ADCD01

06N20W04DCCB01

1 1 1 1

I I I

ASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASON 

1994 1995 1996 1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

80 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
50

55

60

65

70

06N20W09CBCC01

I I I I I I 1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I

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ASONDJFMAMJ JASONDJ FMAMJ JASONDJFMAMJ J ASON 

1994 1995 1996 1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

FIGURE 21 81
60

65

70

75

10

15

20

LU 25

u_

CC 

CO

Q 30

85

: 06N20W14ACDD01

06N20W14BADB01 /

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06N20W15AACD01

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A S O N D 

1994

JFMAMJJASOND 

1995

JFMAMJJASOND 

1996

JFMAMJJASON 

1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued) 

82 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
70

75

80

06N20W16ADCB01

80

85

90

£ 95

06N20W16BAAD01

20

25

30

35

: 06N19W07BABC01

A S O N D 

1994

JFMAMJJASOND 

1995

JFMAMJJASOND 

1996

JFMAMJJASON 

1997

Figure 21. Hydrographs of water levels in wells of the monitoring network (Continued)

FIGURE 21 83
Table 6. Physical properties and major-ion concentrations for water from wells

[Location number numbering system described in text. Constituents are dissolved, except as indicated. Collecting agency: MBMG, Montana Bureau of 

Mines and Geology, Butte, Mont.; USGS, U.S. Geological Survey, Helena, Mont. Analyzing agency: MBMG, Montana Bureau of Mines and Geology, 

Analytical Division, Butte, Mont; UM, University of Montana, Missoula, Mont.; NWQL, USGS National Water Quality Laboratory, Arvada, Colo. 

Abbreviations: (AS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; mg/L, milligrams per liter. Symbols: <, less than minimum 

reporting level; , no data]

Location 

number

10N20W02ABBC01

10N20W10ACBC01

10N20W10CBBD01

10N20W11CDCD01

10N20W12ACDB01

10N20W12ADCB01

10N20W12ADDC01

10N20W12DAAA01

10N20W12DABD01

10N20W12DADA01

10N20W12DDDC01

10N20W13BBA01

10N19W05CCCC01

10N19W05CCCD01

10N19W05CDCC01

10N19W05DCDD01

10N19W06CDCB01

10N19W06CDDA01

10N19W06CDDD01

10N19W06DCCC01

10N19W06DCDA01

10N19W06DDCC01

10N19W07ADBC01

Date

08-03-94

06-23-80

03-10-94

10-26-95

03-10-94

12-14-95

08-24-94

08-28-95

09-13-95

08-15-94

08-15-94

08-28-95

08-15-94

11-19-96

01-07-97

02-26-97

04-03-97

05-19-97

06-24-97

06-24-972

08-19-97

10-15-97

09-27-94

09-15-95

05-12-80

08-29-95

08-29-95

08-10-94

08-10-942

08-15-94

08-03-94

06-08-95

09-12-95

09-27-94

06-08-95

08-28-95

08-10-94

08-10-94

08-10-942

08-10-94

09-12-95

08-15-94

08-10-94

08-15-94

09-13-95

09-13-952

Specific 

conductance, 

field 

(US/cm)

138

97.0

46.0

63.0

106

143

264

354

344

338

286

283

292

294

303

304

305

287

292

292

298

-

216

209

-

297

443

340

340

-

504

-

572

306

-

421

404

409

409

419

400

277

359

-

375

375

pH, 

field 

(standard 

units)

-

-

6.5

6.6

6.6

7.2

-

-

7.2

-

-

-

-

-

~

-

-

-

-

-

-

-

-

7.1

-

-

-

-

-

-

-

-

7.2

-

-

-

3.0

-

-

-

7.2

-

-

-

7.4

7.4

Temper- Oxygen' Cai- Magne- _ .. Potas- Bicar- dis- . . Sodium . i 

ature, . . cium sium , sium Donate solved, . . (mg/L as water (mg/L as (mg/L as r^ (mg/L as (mg/L as

<°C) (me^} Ca) Mg) mj K) HC03)

14.5

11.5 - 8.5 2.0 7.3 1.5

6.0 - 5.1 1.6 2.5 .60

n.o

11.5 - 9.1 2.6 9.0 1.6

14.0

13.5 .. .. .. ,

12.5

12.5 8.6 48 12 8.6 2.4 210

13.0

13.5

14.0

13.0

13.0

11.5

11.5

11.9

13.5

12 6

12.6

12.0

..

13.5

13.0 8.5 28 6.8 5.7 2.5 124

8.5 1.9 4.2 1.1

no

16.0

11.5

11.5

10.5

_

11.5 8.8 70 20 24 4.2 322

13.5

-

12 5

12.0

no

n.o

11.5

10.5 7.6 49 13 16 4.0 235

12.5

12.5

11.5 9.4 53 13 6.2 2.6 203

11.5 9.4 53 13 6.1 2.4 203

Carbonate1 

(mg/L as 

C03)

-

-

~

~

-

-

-

-

0

-

-

-

~

»

-

-

-

-

-

-

~

-

-

0

-

-

-

-

-

-

-

0

-

-

-

-

-

-

0

-

-

0

0

84 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
ON ON , 

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ABBCOl ACBCOl
Table 6. Physical properties and major-ion concentrations for water from wells (Continued)

Location 

number

10N19W07BAAD01

10N19W07BACB01

10N19W07BCBB01

10N19W07BDAD01

10N19W07BDBB01

10N19W07CAAB01

10N19W07CABD01

10N19W07CACC01

10N19W07CDAA01

10N19W07CDBA01

10N19W07CDCC01

10N19W07DABB01

10N19W07DBBC01

10N19W07DBDA01

10N19W07DDCD01

10N19W07DDDC01

10N19W08ABBC01

10N19W08ADAD01

10N19W08ADDC01

10N19W08BADD01

10N19W08BBDD01

10N19W08BCAD01

Date

08-10-94

11-19-96

01-07-97

02-26-97

04-03-97

05-20-97

05-20-972

06-24-97

08-19-97

10-15-97

09-27-94

09-27-942

06-08-95

09-12-95

08-24-94

09-27-94

08-10-94

08-15-94

09-15-95

08-15-94

09-27-94

09-27-94

08-15-94

09-27-94

09-13-95

08-28-95

08-28-952

08-15-94

08-28-95

08-24-94

08-24-94

08-24-942

08-02-94

11-19-96

01-07-97

02-26-97

04-03-97

04-03-972

05-20-97

06-23-97

08-19-97

10-15-97

08-02-94

06-08-95

08-02-94

06-08-95

09-12-95

09-27-94

08-02-94

08-02-942

08-10-94

Specific pH, 

conduct- field 

ance, (standfield ard 

(|iS/cm) units)

386

367

378

378

372

360

360

365

396

306

306

295 7.2

366

351

353

267

251 7.2

272

327

214

228

267 6.9

267 6.9

334

334

263

199

124

185

185

274

403

443

434

404

404

288

273

445

..

339

_

343

343

341 8.1

337

315

315

271

Temperature, 

water

(°C)

12.0

12.0

10.8

11.1

11.5

11.8

11.8

11.0

11.2

-

11.5

11.5

-

13.0

13.5

14.0

12.5

12.5

11.0

12.0

12.0

11.0

11.5

11.5

11.5

12.0

12.0

13.0

11.5

11.0

10.5

10.5

12.0

11.2

11.1

8.3

11.3

11.3

10.9

10.9

10.8

-

14.0

-

12.5

12.5

13.5

15.5

15.5

15.5

16.5

Oxygen, ca_ Magne_ Potas. Bicar. Carbondis- . . Sodium . i i 

, , cium sium , sium bonate* ate* solved, , , _ (mg/L as , _ , _ , (mg/L as (mg/L as rl . (mg/L as (mg/L as (mg/L as

(mg^L) Ca) Mg) K) HC03) C°3)

_

..

..

_

..

..

..

..

..

9.0 40 9.6 8.8 2.5 178 0

..

..

..

_

8.7 33 10 3.7 1.7 145 0

..

..

_

..

7.4 36 9.7 4.9 1.8 159 0

..

..

..

..

..

..

..

-

..

..

..

..

-

..

..

..

..

36 12 20 3.2 187 0

..

-

86 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Alkalinity1 

(ing/Las 

CaC03)

--

--

--

--

--

--

-

-

-

-

-

-

--

146

--

--

--

--

119

-

-

--

-

--

130

-

--

--

-

--

-

--

--

-

-

-

-

-

--

-

--

-

-

-

-

-

153

--

--

-

-

Sulfate 

(ing/Las 

S04)

8.8

8.5

9.1

8.9

7.6

8.6

9.1

9.4

7.3

8.4

4.7

4.7

4.8

5.0

5.1

5.0

4.9

4.7

5.0

5.3

4.5

5.1

5.0

4.8

5.0

5.1

5.3

4.7

5.2

5.6

6.6

4.8

5.0

6.5

7.6

7.8

7.6

7.2

6.1

6.8

8.6

9.6

18.0

18.0

19.0

19.0

20

17.0

37.0

37.0

18.0

Chloride Fluoride Silica 

(mg/L (mg/L as (mg/L 

as Cl) F) as SiO2)

5.7

..

5.0

5.0

3.9

4.7

5.1

5.2

59

6.0

1.5

1.5

1.8

1.5 .20 34

2.0

1.6

2.7

1.5

1.0 .10 16

1.4

1.3

1.5

1.3

1.2

1.0 <.10 19

2.0

2.0

4.5

1.2

1.1

1.1

1.2

1.6

-

2.3

3.0

3.1

2.6

2.6

3.0

3.7

2.0

5.1

5.1

5.2

5.1

5.5 .50 18

4.9

7.1

7.1

5.3

Dissolved 

solids, Nitrate 

calcu- (mg/L as 

lated N) 

(mg/L)

3.2

3.2

2.9

2.8

1.9

2.0

2.9

2.8

3.1

2.7

.72

.72

.72

193 .75

.63

1.9

1.3

.86

150 1.8

1.1

1.9

.91

1.5

1.3

163 1.5

2.0

1.9

.8

.82

.73

.63

.64

2.6

4.6

4.9

4.1

2.9

3.9

2.6

2.6

3.4

4.0

<15

<.15

<15

<15

208 <.05

<15

<.15

<.15

<15

Phosphorus Collecting 

(mg/L as agency 

P)

uses

USGS

USGS

uses

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<.20 USGS

USGS

USGS

USGS

USGS

<.20 USGS

USGS

USGS

USGS

USGS

USGS

<20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<.20 USGS

USGS

USGS

USGS

USGS

Analyzing 

agency

UM

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

UM

UM

UM

MBMG

UM

UM

UM

UM

MBMG

UM

UM

UM

UM

UM

MBMG

UM

UM

UM

UM

UM

UM

UM

UM

MBMG

MBMG

MBMG

MBMG

NWQL

MBMG

MBMG

MBMG

MBMG

UM

UM

UM

UM

MBMG

UM

UM

UM

UM

Location 

number

10N19W07BAAD01

10N19W07BACB01

10N19W07BCBB01

10N19W07BDAD01

10N19W07BDBB01

10N19W07CAAB01

10N19W07CABD01

10N19W07CACC01

10N19W07CDAA01

10N19W07CDBA01

10N19W07CDCC01

10N19W07DABB01

10N19W07DBBC01

10N19W07DBDA01

10N19W07DDCD01

10N19W07DDDC01

10N19W08ABBC01

10N19W08ADAD01

10N19W08ADDC01

10N19W08BADD01

10N19W08BBDD01

10N19W08BCAD01

TABLE 6 87
Table 6. Physical properties and major-ion concentrations for water from wells (Continued)

Location 

number

10N19W08BCBB01

10N19W08BCCC01

10N19W08BDAB01

10N19W08BDBB01

10N19W08CBAA01

10N19W08CBDD01

10N19W08CDAC01

10N19W08CDBD01

10N19W08DAAC01

10N19W08DBBD01

10N19W08DCCB01

10N19W08DCCC01

10N19W08DCCC02

10N19W09ABCC01

10N19W09BCCC01

10N19W16BBBC01

10N19W17BAAA01

10N19W17BBDA01

10N19W17BCAB01

10N19W17DBBC01

10N19W18AAAA01

10N19W18AADB01

10N19W18ABAD01

10N19W18ADDC01

10N19W18DBBA01

Date

09-13-95

08-15-94

08-10-94

08-10-94

08-10-94

08-02-94

08-15-94

11-19-96

01-07-97

02-27-97

04-03-97

05-20-97

08-19-97

10-15-97

08-10-94

06-08-95

09-13-95

08-28-95

08-24-94

08-28-95

09-12-95

08-28-95

09-13-95

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

03-24-94

08-28-95

03-10-94

10-26-95

08-02-94

06-08-95

09-27-94

06-08-95

08-24-94

09-15-95

08-10-94

08-24-94

08-24-94

12-14-95

08-24-94

08-28-95

09-13-95

06-08-95

06-08-952

06-08-95

06-08-95

Specific 

conductance, 

field

264

294

386

243

291

306

198

205

219

254

255

236

228

-

338

338

328

257

168

195

187

274

264

-

277

274

269

-

288

-

280

280

266

258

341

341

201

201

184

165

237

182

193

210

168

175

171

-

-

-

186

pH, 

field 

(standard 

units)

7.3

-

-

-

-

-

-

-

-

~

-

-

-

-

~

-

7.1

-

-

-

7.1

-

7.1

-

-

-

~

-

-

-

-

~

7.1

7.2

-

-

~

-

-

7.2

-

-

-

7.3

-

-

6.9

-

-

-

6.9

 , Oxygen, , Temper- £ Calature' solved, C1Um 

water _ ,. (mg/Las 

or field _

( C) (mg/L) Ca)

15.5 .3 23

15.0

12.0

15.0

15.5

11.0

10.0

8.8

8.5

9.2

9.0

11.2

9.3

..

10.5

10.5

10.0 8.2 45

10.0

13.5

13.5

13.5 5.0 22

11.0

10.5 8.6 35

..

10.4

10.9

12.9

16.5

10.5

..

11.0

11.0

10.5 - 33

11.0

11.0

11.0

11.0

11.0

13.5

13.0 7.9 15

11.5

9.5

10.5

12.0

11.5

11.0

10.0 8.4 21

10.0

Magne- .. Potas- Bicar- Carbon- 

. Sodium . . . j ,1 sium _ sium bonate ate

(mg/L as « \ (m§/L as (mg/L as (mg/L as 

Mg) ' K) HCO3) COj)

5.0 25 3.7 109 0

..

..

_

_

_

_

_

..

..

..

14 3.9 1.9 174 0

..

6.8 6.7 2.6 111 0

..

11 3.7 2.1 150 0

..

_

..

_

10 3.7 2.3

..

..

..

_

..

4.3 12 2.6 77 0

..

..

_

..

6.8 3.7 1.8 99 0

_

..

..

..

88 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Alkalinity1 

(mg/L as 

CaC03)

89

--

--

--

--

-

--

--

--

--

--

--

--

--

--

--

142

--

--

--

91

--

123

--

-

-

-

--

-

--

-

--

--

--

-

--

-

--

-

63

--

--

--

--

--

--

81

-

--

--

--

Sulfate 

(mg/L as 

S04)

20

5.4

4.9

8.6

15.0

7.4

5.0

4.6

4.8

5.7

5.1

5.7

4.5

5.3

5.8

6.3

7.5

6.2

3.0

6.9

7.5

5.5

7.5

6.7

6.7

6.4

6.4

6.8

5.6

6.5

6.7

6.3

3.9

7.0

9.8

7.3

5.3

3.3

4.5

5.0

5.2

4.8

5.1

5.3

4.6

4.7

5.0

4.1

4.1

4.5

4.7

Chloride Fluoride Silica 

(mg/L (mg/L as (mg/L 

as Cl) F) as SiO2)

5.5 .50 52

1.3

1.6

21

4.8

1.6

1.2

..

1.4

2.0

1.6

1.6

2.2

2.4

1.5

2.5

1.5 .10 19

1.6

1.2

17

1.5 .20 55

1.6

1.5 <10 22

1.2

1.7

1.6

1.6

1.7

1.7

1.8

1.6

1.6

.65 .16 22

1.6

1.6

1.5

15

1.1

3.2

6.5 .50 68

1.3

1.0

1.1

1.5

< 1.0

1.1

1.0 <.10 19

1.2

1.3

1.2

1.6

Dissolved 

solids, Nitrate 

calcu- (mg/L as 

lated N) 

(mg/L)

189 <.05

1.7

2.4

2.4

<15

3.1

1.3

1.9

1.8

2.3

1.6

1.3

2.2

2.4

2.9

3.3

194 3.5

2.6

.25

.16

157 .10

2.5

168 2.8

3.4

3.1

2.4

2.7

..

3.8

3.5

2.5

2.5

2.3

2.4

4.3

1.9

.2

.37

.73

156 .95

.94

.38

.79

.49

.5

.39

109 .45

.59

.6

.49

.71

Phosphorus Collecting 

(mg/L as agency 

P)

<20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<20 USGS

USGS

USGS

USGS

<.20 USGS

USGS

<20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<.20 MBMG

USGS

USGS

USGS

USGS

USGS

USGS

<20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

<20 USGS

USGS

USGS

USGS

USGS

Analyzing 

agency

MBMG

UM

UM

UM

UM

UM

UM

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

UM

UM

MBMG

UM

UM

UM

MBMG

UM

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

UM

UM

MBMG

UM

UM

UM

UM

UM

UM

MBMG

UM

UM

UM

UM

UM

UM

MBMG

UM

UM

UM

UM

Location 

number

10N19W08BCBB01

10N19W08BCCC01

10N19W08BDAB01

10N19W08BDBB01

10N19W08CBAA01

10N19W08CBDD01

10N19W08CDAC01

10N19W08CDBD01

10N19W08DAAC01

10N19W08DBBD01

10N19W08DCCB01

10N19W08DCCC01

10N19W08DCCC02

10N19W09ABCC01

10N19W09BCCC01

10N19W16BBBC01

10N19W17BAAA01

10N19W17BBDA01

10N19W17BCAB01

10N19W17DBBC01

10N19W18AAAA01

10N19W18AADB01

10N19W18ABAD01

10N19W18ADDC01

10N19W18DBBA01

TABLE 6 89
Table 6. Physical properties and major-ion concentrations for water from wells (Continued)

Location 

number

10N19W19BDAD01

10N19W19DDAA01

10N19W20BAAD01

10N19W21CBBA01

10N19W29ABAC01

10N19W30CACD01

09N20W19ADCA01

09N20W20ACAB01

09N20W20ACAD01

09N20W20CDCD01

09N20W21ACCB01

09N20W21CCAC01

09N20W28CCBB01

09N20W29ADCC01

09N19W33BDBC01

08N21W27DCBC01

08N20W01ACCB01

08N20W01DAAD01

08N20W01DABD01

08N20W02CBDB01

08N20W11BDAA01

08N20W11CCAD01

08N20W12BAAA01

08N20W13BBDB01

08N20W14ABDB01

08N20W23CDDD01

08N20W26BAAC01

08N19W04BDAA01

08N19W07CBBD01

08N19W10BBCA01

08N19W11CDBB01

Date

09-13-95

10-26-95

10-26-95

10-26-95

10-26-95

10-26-952

10-26-95

10-26-95

10-26-95

10-12-95

06-06-96

06-06-962

09-14-95

10-12-95

12-14-95

10-12-95

10-12-952

10-26-95

08-25-95

03-10-94

06-06-96

08-25-95

08-20-92

10-26-95

08-25-95

08-25-95

08-25-95

10-12-95

11-19-96

01-07-97

02-26-97

04-03-97

04-03-972

05-20-97

06-24-97

08-19-97

10-15-97

10-12-95

09-15-95

10-12-95

08-20-92

12-14-95

12-14-952

03-10-94

06-06-96

03-09-94

08-25-95

03-10-94

08-25-95

08-25-95

08-25-952

08-20-92

Specific 

conductance, 

field

(uS/cm)

186

214

210

191

243

243

274

236

141

118

128

128

230

42.9

287

193

193

256

177

67.0

70.6

648

622

626

306

564

60.9

812

813

838

854

860

860

839

866

723

-

622

579

579

386

384

384

602

416

-

169

756

766

288

288

227

pH, 

field 

(standard 

units)

6.9

6.9

7.3

7.1

7.0

7.0

7.4

7.2

6.4

6.4

6.5

6.5

8.3

6.2

7.4

6.6

6.6

6.8

7.4

6.3

6.6

7.6

7.6

7.7

7.7

7.6

7.6

7.9

-

-

-

-

-

-

-

-

7.3

7.5

7.5

7.4

7.8

7.8

7.6

7.2

7.4

7.9

8.1

8.0

7.8

7.8

7.2

Temper- OlL^en' Cal- Magne- disature, , , cium sium solved, , _ , water (mg/L as (mg/L as

<°c> < £> c"> Mg)

10.0 9.1 23 7.2

10.5

14.0

13.5

14.5

14.5

13.5

11.0

12.0

11.0

10.0

10.0

10.0 .4 30 .7

12.5

10.5

10.5

10.5

10.5

18.0

5.5 - 8.4 1.6

8.5

10.5

11.5 6.8 50 13

9.5

13.5

15.0

14.0

11.0

10.3

8.6

8.7

9.0

9.0

9.8

9.8

9.3

..

11.5

14.5 7.8 69 16

14.5

15.0 9.2 34 7.4

12.0

12.0

16.0 - 42 13

16.0

4.5 - 22 4.6

8.5

9.0 - 33 14

10.0

13.5

13.5

8.0 7.2 30 6.3

_ J. Potas- Bicar- Carbon- Sodium . . , i .1 

 sium bonate ate (mg/L as . , , ^ (mg/Las (mg/Las (mg/Las

' K) HCO3) CO3)

4.0 1.9 106 0

..

_

..

-

..

..

..

..

..

18 1.5 130 0

..

..

..

..

..

3.2 1.0 38 0

..

..

71 2.0 359 0

..

..

..

..

..

..

..

..

..

..

..

..

34 8.0 316 0

..

29 7.8 170 0

..

..

68 8.2 258 0

2.6 1.8

130 2.0

..

7.1 2.1 127 0

90 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Alkalinity1 

(mg/L as 

CaCO3)

87

--

-

-

--

-

--

-

-

-

-

-

107

-

--

--

--

--

--

31

-

--

295

--

--

--

--

--

-

--

--

--

--

--

--

--

--

-

259

-

139

--

--

212

--

-

-

-

-

--

-

104

Sulfate 

(mg/L as 

S04)

5.0

13.0

7.7

4.7

25.0

26.0

6.8

5.9

4.3

3.1

2.7

2.7

7.5

3.0

4.8

3.0

3.0

4.5

3.6

<1.0

2.6

11.0

18

16.0

11.0

26.0

38.0

22.0

27.0

25.0

23.0

23.7

24.0

24.3

26.3

26.0

26.0

60.0

35

34.0

24

22.0

24.0

72

44.0

1.4

3.5

18

20.0

4.8

4.9

9.9

Chloride Fluoride Silica 

(mg/L (mg/L as (mg/L 

as CI) F) as SiO2)

1.0 <10 26

4.7

4.8

2.4

5.5

5.5

3.7

4.0

3.9

1.5

1.1

1.1

2.0 .10 17

<1.0

6.4

4.1

4.1

3.1

14

<20 .14 19

<1.0

5.7

11 .80 18

8.0

9.0

11.0

16.0

27.0

24.0

28.0

31.0

36.5

34.0

36.4

47.7

36.0

37.0

12.0

10 .60 51

10.0

21 .40 50

18.0

18.0

19 .27 42

13.0

<.20 .10 13

<1.0

5.3 1.9 17

6.9

1.7

1.7

.60 .20 15

Dissolved 

solids, Nitrate 

caicu- (mg/L as 

lated N) 

(mg/L)

124 .80

.9

.55

.2

1.3

1.3

1.1

.95

3.2

.35

.27

.26

142 <05

<15

<15

.19

.19

<15

<15

.18

..

3.0

361

2.9

1.0

.76

.43

5.4

4.6

5.1

5.9

5.0

5.5

5.3

5.4

5.5

5.4

.33

386 1.5

1.4

257

.19

.53

..

.55

.07

<.15

2.1

2.0

.97

.97

134

Phosphorus 

(mg/L as 

P)

<20

-

-

-

-

-

-

-

--

-

-

-

<.20

-

-

--

-

-

--

<.20

-

-

-

-

-

--

-

-

-

-

~

-

--

-

-

-

-

-

<20

-

-

-

-

<.20

--

<.20

-

<.20

-

-

-

-

Collecting 

agency

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

uses

USGS

USGS

USGS

MBMG

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

MBMG

USGS

MBMG

uses

MBMG

USGS

USGS

USGS

USGS

Analyzing 

agency

MBMG

UM

UM

UM

UM

UM

UM

UM

UM

UM

UM

UM

MBMG

UM

UM

UM

UM

UM

UM

MBMG

UM

UM

NWQL

UM

UM

UM

UM

UM

MBMG

MBMG

MBMG

MBMG

NWQL

MBMG

MBMG

MBMG

MBMG

UM

MBMG

UM

NWQL

UM

UM

MBMG

UM

MBMG

UM

MBMG

UM

UM

UM

NWQL

Location 

number

10N19W19BDAD01

10N19W19DDAA01

10N19W20BAAD01

10N19W21CBBA01

10N19W29ABAC01

10N19W30CACD01

09N20W19ADCA01

09N20W20ACAB01

09N20W20ACAD01

09N20W20CDCD01

09N20W21ACCB01

09N20W21CCAC01

09N20W28CCBB01

09N20W29ADCC01

09N19W33BDBC01

08N21W27DCBC01

08N20W01ACCB01

08N20W01DAAD01

08N20W01DABD01

08N20W02CBDB01

08N20W11BDAA01

08N20W11CCAD01

08N20W12BAAA01

08N20W13BBDB01

08N20W14ABDB01

08N20W23CDDD01

08N20W26BAAC01

08N19W04BDAA01

08N19W07CBBD01

08N19W10BBCA01

08N19W11CDBB01

TABLE 6 91
Table 6. Physical properties and major-ion concentrations for water from wells (Continued)

Location 

number

07N21W13BBAD01

07N21W25CABC01

07N21W36DDDC01

07N20W32DDDA02

07N20W34CCCD01

07N20W34CDDB01

07N20W36CCCA01

06N21W01ACDA01

06N21W01CADD01

06N21W01CBAB01

06N21W02ABBD01

06N21W02CADD01

06N21W03ACBA01

06N21W03CAAC01

06N21W03CCDD01

06N21W03DDAA01

06N21W09DADA01

06N21W10BDDD01

06N21W11ABAA01

06N21W11CAAA01

06N21W11CBCA01

06N21W11CBDC01

Date

10-26-95

08-17-92

08-17-922

12-14-95

08-17-92

12-14-95

06-20-84

03-09-94

08-25-95

03-09-94

07-27-95

07-27-95

12-14-95

05-01-95

04-18-95

05-01-95

03-09-94

08-17-95

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

05-02-95

05-01-95

05-01-95

11-18-96

01-06-97

02-25-97

04-02-97

04-02-972

04-02-972

06-23-97

08-18-97

10-14-97

05-01-95

05-01-95

09-07-95

05-01-95

09-07-95

05-01-95

06-18-84

05-01-95

09-06-95

04-18-95

05-01-95

05-01-95

05-01-952

Specific 

conductance, 

field

(US/cm)

233

96.0

96.0

82.2

86.0

89.5

34.0

32.0

48.9

345

473

417

313

28.0

71.0

74.0

82.0

90.3

89.0

88.6

86.5

80.0

83.0

86.0

103

-

25.8

25.4

88.6

81.0

89.6

-

85.0

85.0

85.0

76.0

80.0

-

197

87.5

119

266

263

109

102

102

100

136

144

161

161

pH, 

field 

(standard 

units)

7.2

6.8

6.8

7.6

6.5

6.9

5.5

6.0

6.6

7.1

7.6

7.6

7.8

6.7

6.9

7.0

6.1

7.3

~

-

-

-

-

-

-

-

6.7

6.8

6.5

-

-

-

-

-

-

-

~

-

7.3

6.5

5.7

8.5

8.1

7.2

6.8

7.5

6.8

6.8

7.0

7.8

7.8

Temper- Oxygen' Cal- Magne- disature, . . cium sium solved, , _ ,n water (mg/L as (mg/L as

(°C) Ca) Mg)

8.5

11.0 7.4 8.3 1.5

11.0 7.4 8.2 1.5

9.5

11.0 1.5 6.1 2.0

10.0

10.3 - 3.3 .7

11.0 -- 3.8 .9

14.0

11.5 - 45 10

10.5

12.0

12.0

10.0

11.0

10.0

11.5 -- 10 2.5

15.0

11.0

9.7

9.2

11.2

13.5

12.4

11.7

10.0

9.0

9.5

10.9

7.6

6.9

6.9

6.9

10.7

11.3

..

8.5

10.0

14.5 6.3 11 3.0

7.5

14.5 .4 22 6.1

6.5

11.5 - 6.0 1.6

9.5

12.0 .4 5.7 1.6

8.5

6.5

11.0

11.0

_ .. Potas- Bicar- Carbon- Sodium . i , i sium Donate ate

5f x (mg/L as (mg/L as (mg/L as 

' K) HCO3) CO3)

~

8.7 1.7 54 0

8.7 1.6 54 0

..

7.5 1.2 45 0

..

2.4 1.0 20 0

2.2 1.6

..

12 3.7

..

..

..

..

..

2.9 .70

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

7.3 2.2 41 0

..

29 .44 151 0

..

12.4 1.6 59 0

..

11 1.4 59 0

..

..

_

92 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Alkalinity1 

(ing/Las 

CaCO3)

-

44

44

-

37

-

16

-

-

-

-

--

-

-

-

-

--

-

--

--

--

--

--

-

--

--

--

--

--

--

--

--

--

--

--

--

-

--

--

--

34

--

124

--

48

--

48

--

-

--

-

Sulfate 

(ing/Las 

S04)

10.0

1.2

1.2

<2.0

1.6

<2.0

0.9

<1.0

<2.0

2.6

13.0

12.0

5.9

<2.0

2.9

<2.0

<1.0

2.4

3.0

2.5

2.8

2.9

3.0

3.7

2.5

2.3

<2.0

<2.0

5.2

<2.5

<2.5

2.6

<2.5

<2.5

2.3

3.0

<2.5

2.7

<2.0

<2.0

2.5

5.3

5.0

<2.0

1.6

<2.0

<2.5

3.1

<2.0

<2.0

<2.0

Chloride Fluoride Silica 

(mg/L (mg/L as (mg/L 

as CI) F) as SiO2)

1.8

.50 .10 27

.50 .10 28

1.1

1.0 <.10 35

1.6

.40 .10 14

.40 .10 14

<1.0

1.7 .27 34

44

7.0

3.9

<1.0

1.7

1.1

.50 .14 33

2.1

1.8

1.1

1.5

1 .3

1.3

1.9

3.0

2.9

<1.0

1.4

1.9

0.9

0.9

1.0

1.0

1.0

1.1

0.78

0.69

0.98

2.6

3.6

14 <10 30

17

1.0 2.9 18

1.3

.60 .20 55

1.0

.50 .20 54

2.6

2.3

1.1

1.3

Dissolved 

solids, Nitrate 

calcu- (mg/L as 

lated N) 

(mg/L)

.5

76

77

.35

77

<15

34 .10

.28

.25

1.2

.62

.41

1.4

<.15

<.15

.17

1.1

1.9

1.8

1.6

1.4

1.4

1.3

1.7

3.2

3.1

<15

<15

5.5

.9

2.8

1.3

1.3

1.3

1.6

.87

.77

.79

.17

.61

91 .20

<.15

160 <05

.18

109 .06

<15

<.05

<15

.29

<.15

<15

Phosphorus 

(mg/L as 

P)

-

-

-

--

--

-

.30

<.20

-

<.20

-

-

-

-

--

-

.20

--

-

-

--

-

-

-

-

-

-

-

-

--

-

-

--

--

--

--

-

-

-

-

<.20

-

<20

-

.40

-

<.20

-

-

-

Collecting 

agency

USGS

USGS

USGS

USGS

USGS

USGS

MBMG

MBMG

USGS

MBMG

USGS

USGS

USGS

USGS

USGS

USGS

MBMG

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

MBMG

USGS

USGS

USGS

USGS

USGS

USGS

Analyzing 

agency

UM

NWQL

NWQL

UM

NWQL

UM

MBMG

MBMG

UM

MBMG

UM

UM

UM

UM

UM

UM

MBMG

UM

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

UM

UM

UM

MBMG

MBMG

MBMG

MBMG

MBMG

NWQL

MBMG

MBMG

MBMG

UM

UM

MBMG

UM

MBMG

UM

MBMG

UM

MBMG

UM

UM

UM

UM

Location 

number

07N21W13BBAD01

07N21W25CABC01

07N21W36DDDC01

07N20W32DDDA02

07N20W34CCCD01

07N20W34CDDB01

07N20W36CCCA01

06N21W01ACDA01

06N21W01CADD01

06N21W01CBAB01

06N21W02ABBD01

06N21W02CADD01

06N21W03ACBA01

06N21W03CAAC01

06N21W03CCDD01

06N21W03DDAA01

06N21W09DADA01

06N21W10BDDD01

06N21W11ABAA01

06N21W11CAAA01

06N21W11CBCA01

06N21W11CBDC01

TABLE 6 93
Table 6. Physical properties and major-ion concentrations for water from wells (Continued)

Location 

number

06N21W11CDCB01

06N21W11DCCA01

06N21W12ABAB01

06N21W12BDDD01

06N21W13BADC01

06N21W13BBAB01

06N21W13CCCD01

06N21W13DBBD01

06N21W14BCBD01

06N21W14BDAC01

06N21W14DAAD01

06N21W15ABBB01

06N21W15ADBC01

06N21W15CDDD01

06N21W21ADDB01

06N21W22AADC01

06N21W22BCCA01

06N21W22CACA01

06N21W23ADAA01

06N21W23BABB01

06N21W23BDDD01

06N21W23CABC01

06N21W23CBCB01

06N21W23CDCB01

06N21W23DADA01

06N21W23DADD01

Date

06-15-95

09-06-95

10-26-94

04-18-95

04-18-95

09-06-95

04-18-95

04-18-95

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

10-14-97

10-26-94

05-01-95

05-01-95

10-26-94

09-06-95

09-06-952

10-26-94

05-01-95

06-15-95

06-10-84

08-17-92

10-26-94

10-26-942

10-26-94

05-01-95

09-06-95

08-30-94

08-30-94

10-26-94

10-26-94

08-30-94

06-15-95

06-15-952

08-09-95

09-06-95

06-08-84

09-15-94

08-30-94

09-15-94

09-15-942

08-08-95

09-15-94

09-15-942

09-28-94

09-28-942

Specific 

conductance, 

field

(uS/cm)

121

105

210

59.0

149

133

143

90.0

87.8

88.9

79.1

80.0

81.0

83.0

86.0

-

89.9

106

57.3

82.2

84.5

84.5

58.3

75.8

101

53.0

52.0

50.3

50.3

122

40.1

39.0

124

120

47.2

36.2

36.2

79.0

79.0

79.0

79.4

99.0

99.0

105

48.4

48.4

48.4

54.0

54.0

54.0

54.0

pH, 

field 

(standard 

units)

7.2

6.6

7.8

6.6

6.9

6.3

7.8

7.6

-

-

-

-

-

-

-

-

6.2

6.4

6.9

7.1

7.0

7.0

6.1

6.7

7.6

6.2

6.3

6.4

6.4

7.2

6.7

5.7

9.6

6.4

6.2

6.3

6.3

7.1

7.1

7.1

6.6

6.7

6.7

6.6

6.1

6.1

6.1

6.1

6.1

6.1

6.1

Temper- Oxygen' Cal- Magne- disature, , , cium sium solved water ' (mg/L as (mg/L as

(°C) Ca) Mg)

12.0

10.0 .3 7.6 2.2

10.0

10.0

9.5

10.0 1.8 11 2.8

11.5

11.0

10.9

10.6

10.8

13.0

14.9

12.9

13.0

11.5

11.0

10.0

12.0

12.0 9.2 12 1.8

12.0 9.2 12 1.8

9.0

10.0

12.0

10.8 - 5.8 1.3

9.5 8.4 5.2 1.1

9.5

9.5

11.0

9.5

9.5 6.5 3.4 1.2

11.0

13.5

11.5

12.5

12.5

10.0

10.0

10.0

11.5 7.4 7.3 1.8

11.0 -- 10 2.5

11.0

12.0

10.5

10.5

10.5

11.0

11.0

11.0

11.0

 .. Potas- Bicar- Carbon- Sodium . , . i .1 sium bonate ate

ff . (mg/L as (mg/L as (mg/L as 

Na) K) HC03) C03)

-

10 1.5 62 0

-

..

10 1.6 78 0

~

_

-

..

-

..

..

..

-

-

..

2.5 .59 47 0

2.5 .79 47 0

..

..

3.4 .60 34 0

3.1 .60 28 0

..

..

2.5 1.4 22 0

..

..

..

..

..

..

7.3 .59 44 0

9.1 .7 62.5 0

-

-

94 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Alkalinity1 

(mg/L as 

CaC03)

--

51

--

--

-

64

--

--

--

--

--

-

-

--

--

-

-

--

-

-

39

39

-

--

--

28

23

-

--

--

--

18

-

--

--

-

--

--

-

--

36

51

-

--

--

--

--

--

--

-

-

Sulfate 

(mg/L as 

S04)

<2.0

2.5

11.0

<2.0

<2.0

<2.5

<2.0

<2.0

<2.5

<2.5

<2.5

<2.5

<2.5

<2.5

<2.5

<2.5

2.3

<2.0

<2.0

<2.0

<2.5

<2.5

<2.0

<2.0

2.3

.70

.80

<2.0

<2.0

<2.0

<2.0

<2.5

<2.0

<2.0

<2.0

<2.0

<2.0

2.3

2.7 '

<2.0

<2.5

1.5

<2.0

<2.0

<2.0

<2.0

<2.0

<2.0

<2.0

<2.0

<2.0

Chloride Fluoride Silica 

(mg/L (mg/L as (mg/L 

as Cl) F) as SiO2)

<1.0

.50 .20 40

7.2

<1.0

2.1

1.5 .20 29

1.0

1.1

.8

<.05

1.0

.8

9

.86

.89

.87

2.7

2.8

<1.0

< 1.0

<50 .10 35

<50 .20 35

<1.0

<1.0

1.7

.30 .10 31

.20 <10 27

<1.0

<1.0

1.2

<1.0

<.50 <10 22

1.9

2.7

4.6

<1.0

<1.0

<1.0

<1.0

<1.0

<50 <1.0 42

.6 .3 45

1.1

1.4

< 1.0

<1.0

<1.0

1.2

1.1

<1.0

<1.0

Dissolved 

solids, Nitrate 

calcu- (mg/L as 

lated N) 

(mg/L)

<15

97 <05

.7

.16

<15

<05

.6

.4

.4

.4

.4

.3

.3

.37

.34

.3

.8

.3

<15

<15

.10

.10

.3

<15

.16

61 .15

52

.18

.16

<15

<15

.15

.17

.25

<15

<15

<15

.16

.22

.21

.15

102 .28

.28

.31

<15

<15

.22

.27

.18

.34

.26

Phosphorus Collecting 

(mg/L as agency 

P)

USGS

<.20 USGS

USGS

USGS

USGS

<.20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<20 USGS

<20 USGS

USGS

USGS

USGS

.40 MBMG

USGS

USGS

USGS

USGS

USGS

<20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<20 USGS

.3 MBMG

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

Analyzing 

agency

UM

MBMG

UM

UM

UM

MBMG

UM

UM

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

UM

UM

UM

UM

MBMG

MBMG

UM

UM

UM

MBMG

NWQL

UM

UM

UM

UM

MBMG

UM

UM

UM

UM

UM

UM

UM

UM

MBMG

MBMG

UM

UM

UM

UM

UM

UM

UM

UM

UM

Location 

number

06N21W11CDCB01

06N21W11DCCA01

06N21W12ABAB01

06N21W12BDDD01

06N21W13BADC01

06N21W13BBAB01

06N21W13CCCD01

06N21W13DBBD01

06N21W14BCBD01

06N21W14BDAC01

06N21W14DAAD01

06N21W15ABBB01

06N21W15ADBC01

06N21W15CDDD01

06N21W21ADDB01

06N21W22AADC01

06N21W22BCCA01

06N21W22CACA01

06N21W23ADAA01

06N21W23BABB01

06N21W23BDDD01

06N21W23CABC01

06N21W23CBCB01

06N21W23CDCB01

06N21W23DADA01

06N21W23DADD01

TABLE 6 95
Table 6. Physical properties and major-ion concentrations for water from wells (Continued)

Location 

number

06N21W23DBDA01

06N21W23DDAA01

06N21W23DDAD01

06N21W23DDBB01

06N21W23DDCB01

06N21W23DDDA01

06N21W24BAAC01

06N21W24CCAC01

06N21W24CCBB01

06N21W24CCBB02

06N21W24CCCB01

06N21W25DBAA01

06N21W26AADD01

06N21W26ABAD01

06N21W26BBCA01

06N21W26CBAB01

06N21W26DBAD01

06N21W26DBDD01

06N21W27ADBC01

Date

07-14-95

08-09-95

09-15-94

08-09-95

09-15-94

08-08-95

09-05-95

09-15-94

08-08-95

09-05-95

09-15-94

08-08-95

09-15-94

08-08-95

10-26-94

09-06-95

09-15-94

08-08-95

09-05-95

11-18-96

01-06-97

02-25-97

04-02-97

05-19-97

06-23-97

08-18-97

08-18-972

10-14-97

09-15-94

09-15-94

09-1 5-942

08-08-95

08-08-952

09-15-94

08-09-95

08-18-92

12-14-95

08-30-94

08-30-94

08-30-94

08-30-942

08-30-94

03-08-94

09-15-94

08-30-94

11-18-96

11-18-962

01-06-97

02-25-97

04-02-97

05-19-97

Specific 

conductance, 

field

(US/cm)

43.9

43.9

50.8

50.8

51.7

51.7

55.0

51.4

51.4

52.2

73.3

73.3

59.2

59.2

92.9

93.0

63.3

63.3

70.1

69.0

74.0

71.8

70.0

66.0

70.0

71.0

71.0

-

60.2

57.3

57.3

57.3

57.3

72.0

72.0

284

293

90.3

212

45.3

45.3

97.9

146

107

108

111

111

113

111

108

107

pH, 

field 

(standard 

units)

6.7

6.7

6.3

6.3

6.3

6.3

6.0

6.3

6.3

6.0

6.6

6.6

6.2

6.2

6.6

6.1

6.2

6.2

5.8

~

-

-

-

-

-

_

-

-

6.3

6.5

6.5

6.5

6.5

5.8

5.8

6.9

7.2

6.6

7.2

6.3

6.3

6.7

6.9

7.2

6.4

-

-

-

-

-

-

Temperature, 

water

11.0

11.0

14.5

14.5

12.5

12.5

12.5

10.0

10.0

10.5

10.0

10.0

11.0

11.0

9.0

9.0

12.5

12.5

12.5

12.3

10.6

11.8

12.3

14.0

11.7

11.7

11.7

-

14.0

14.5

14.5

14.5

14.5

11.0

11.0

12.5

12.0

10.0

11.5

10.5

10.5

11.5

10.5

13.0

10.0

10.4

10.4

9.6

10.9

11.1

12.9

yg Cal- Magne- 0 Potas- Bicar- Carbon- dis- . . Sodium . .1 *. i cium sium ( _ sium bonate1 ate*

$ f IH (mgfLas (mg/L as W" (mg/L as (mg/L as (mg/L as 

(mefL) Ca) Mg) K) HC°3) C°3)

_

..

..

..

_

..

7.1 4.4 1.4 3.9 1.7 23 0

..

..

4.4 5.0 1.1 3.3 2.4 22 0

..

..

..

..

..

0.4 11 3.1 3.0 1.1 53 0

..

..

6.7 5.7 2.2 4.3 1.9 29 0

..

..

..

..

..

..

..

_

..

..

_

..

..

6.4 38 9.0 4.6 2.9 171 0

_

..

..

..

..

_

13 3.2 13 3.8

..

..

..

..

..

..

..

96 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
.f1!4*', Sulfate Unity1 , _ 

, _ (mg/L as (mg/L as »

CaC03) S°4)

< 2.0

< 2.0

< 2.0

< 2.0

< 2.0

< 2.0

19 <2.5

< 2.0

< 2.0

18 <2.5

< 2.0

< 2.0

< 2.0

< 2.0

< 2.0

43 <2.5

<2.0

2.5

24 2.5

<2.5

<2.5

<2.5

<2.5

<2.5

2.7

<2.5

<2.5

2.8

< 2.0

< 2.0

2.0

2.6

2.2

< 2.0

< 2.0

140 3.9

4.3

< 2.0

2.0

< 2.0

<2.0

< 2.0

<1.0

4.4

< 2.0

<2.5

<2.5

<2.5

<2.5

<2.5

1.9

Chloride Fluoride Silica 

(mg/L (mg/L as (mg/L 

as Cl) F) as SiO2)

1.1

1.0

<1.0

1.7

1.1

1.4

1.5 <.10 27

12.0

2.3

2.0 <10 26

< 1.0

<1.0

< 1.0

1.4

1.2

1.0 <10 38

1.4

2.1

2.5 <10 28

1.8

2.6

1.6

1 .7

2.0

2.3

2.4

2.3

2.0

< 1.0

< 1.0

<1.0

2.0

1.4

1.7

14

0.80 .20 16

2.5

1.1

2.3

<1.0

<1.0

1.3

1.3 .21 62

1.6

3.6

3.4

3.3

3.5

3.6

3.3

3.4

Dissolved 

solids, Nitrate 

calcu- (mg/L as 

lated N) 

(mg/L)

.22

.17

.16

.39

.38

.51

.50

<15

.62

.30

.15

<15

.2

.37

<.15

<05

.36

1.1

65 .75

.50

.57

.64

.87

1.0

1.2

.86

.85

.79

.48

.51

.51

.71

.42

.47

.44

160

.75

.15

<15

.17

.17

.57

.55

<15

1.4

1.6

1.6

1.6

1.4

1.6

1.2

Phosphorus Collecting 

(mg/L as agency 

P)

USGS

USGS

USGS

USGS

USGS

USGS

<.20 USGS

USGS

USGS

<.20 USGS

USGS

USGS

USGS

USGS

USGS

<.20 USGS

USGS

USGS

<20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

.20 MBMG

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

Analyzing 

agency

UM

UM

UM

UM

UM

UM

MBMG

UM

UM

MBMG

UM

UM

UM

UM

UM

MBMG

UM

UM

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

UM

UM

UM

UM

UM

UM

UM

NWQL

UM

UM

UM

UM

UM

UM

MBMG

UM

UM

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

Location 

number

06N21W23DBDA01

06N21W23DDAA01

06N21W23DDAD01

06N21W23DDBB01

06N21W23DDCB01

06N21W23DDDA01

06N21W24BAAC01

06N21W24CCAC01

06N21W24CCBB01

06N21W24CCBB02

06N21W24CCCB01

06N21W25DBAA01

06N21W26AADD01

06N21W26ABAD01

06N21W26BBCA01

06N21W26CBAB01

06N21W26DBAD01

06N21W26DBDD01

06N21W27ADBC01

TABLE 6 97
Table 6. Physical properties and major-ion concentrations for water from wells (Continued)

Location 

number

06N21W27BABA01

06N21W27BBAA01

06N21W34ABCD01

06N20W01BABB01

06N20W01CDCD01

06N20W02AADC01

06N20W02BBDA01

06N20W02CCAA01

06N20W02DCDC01

06N20W03BDBB01

06N20W03BDCC01

06N20W03CCDB01

06N20W04AABC01

06N20W04ACCD01

06N20W04ADCD01

06N20W04CCCD01

06N20W04DCCB01

Date

06-23-97

08-18-97

10-14-97

08-30-94

03-08-94

08-15-95

08-15-95

07-27-95

09-14-95

06-20-84

06-15-95

09-07-95

11-19-96

01-07-97

02-26-97

04-03-97

04-03-972

05-20-97

06-24-97

08-19-97

10-15-97

07-27-95

07-14-95

07-27-95

07-27-952

07-14-95

07-27-95

03-09-94

07-14-95

06-15-95

07-27-95

07-27-95

06-15-95

01-07-97

02-27-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

06-15-95

06-15-95

06-15-952

09-14-95

01-07-97

01-07-972

02-26-97

04-03-97

04-03-972

05-20-97

Specific 

conductance, 

field

OiS/cm)

107

108

-

99.2

83.0

83.9

100

396

378

413

395

204

324

389

428

418

418

421

446

330

-

453

661

558

558

532

328

499

505

463

449

385

359

364

365

361

353

359

365

-

363

436

436

390

393

393

403

411

411

411

pH, 

field 

(standard 

units)

-

-

-

6.7

6.4

7.8

6.6

8.0

8.0

7.2

7.3

7.4

- ,

-

-

-

-

-

--

-

-

7.3

7.8

7.6

7.6

7.5

7.7

7.1

7.2

7.6

7.3

7.3

7.6

-

-

-

-

-

-

-

7.5

7.5

7.5

7.5

_

-

-

-

-

-

Temper- °*** Cal- disature, . . cium solved, _ water _ , . (ing/Las 0 field £

( C) (mg/L) Ca)

11.8

11.0

-

12.0

9.5 - 8.4

11.0

11.0

14.5

13.5 6.6 21

9.5 -- 56

10.5

11.0 7.4 24

10.9

9.2

8.5

9.0

9.0

9.3

10.2

10.7

..

15.0

12.5

10.5

10.5

12.0

12.0

10.0 - 72

11.5

10.5

11.5

12.5

12.0

8.2

9.5

9.7

10.2

10.7

11.1

-

10.5

13.0

13.0

12.5 8.2 49

10.7

10.7

10.3

11.3

11.3

11.8

Magne- .. Potas- Bicar- Carbon- Sodium . . , i ^ 1 sium .. sium bonate ate

(mg/L as r' (mg/L as (mg/L as (mg/L as 

Mg) Na) K) HC03) C03)

..

_

..

..

1.1 8.3 1.0

..

3.0 60 4.2 199 0

13.1 19 2.2 260 0

..

5.6 13 1.5 119 0

_

..

-

..

..

_

..

..

..

..

-

_

9.0 22 4.0

-

-

_

..

..

_

..

..

..

..

..

--

..

-

15 14 2.9 244 0

-

-

..

..

-

98 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Alkalinity1 

(mg/Las 

CaCO3)

--

--

--

--

--

-

--

--

163

213

-

98

--

--

-

-

--

--

--

--

--

--

-

--

-

--

--

--

--

--

-

-

-

--

-

-

--

--

--

-

--

--

200

-

--

-

--

--

-

Sulfate 

(mg/Las 

S04)

2.1

<2.5

<2.5

<2.0

<1.0

<2.0

<2.0

14.0

23

7.2

6.1

2.5

3.8

4.6

6.8

6.5

7.5

8.5

6.6

<2.5

3.8

18.0

37.0

15.0

16.0

6.6

6.0

13

12.0

8.5

11.0

6.3

8.7

8.7

8.9

8.0

8.7

9.3

4.9

8.4

6.6

7.1

7.7

5.0

5.2

6.0

5.7

5.4

5.9

6.4

Chloride Fluoride Silica 

(mg/L (mg/L as (mg/L 

as Cl) F) as SiO2)

3.2

3.1

3.1

<1.0

<.20 .08 40

1.0

1 .3

5.9

8.0 1.3 47

2.7 .60 39

4.0

1.0 .80 40

..

2.4

4.4

3.9

4.4

6.3

3.9

.79

1 .5

18.0

23.0

7.0

7.8

2.9

1.9

3.6 .42 33

3.9

3.4

5.1

3.2

3.9

3.7

3.9

3.2

3.8

3.7

2.2

3.6

3.6

5.0

5.0

2.5 .40 41

2.8

2.8

3.3

2.9

3.1

3.7

Dissolved 

solids, Nitrate 

calcu- (mg/L as 

lated N) 

(mg/L)

1.2

1.2

1.2

.24

.11

<15

.17

.69

268 .60

276 1.81

3.5

151 .85

.6

.90

1.5

1.8

1.4

1.5

.94

.23

.47

2.4

1.7

.49

.50

.62

.21

.92

.52

1.6

3.1

2.0

.81

.80

.80

.94

.80

.88

.51

.76

1.6

2.9

2.9

255 1.3

1.7

1.7

1.9

1.6

2.1

1.8

Phosphorus Collecting 

(mg/L as agency 

P)

uses

uses

uses

uses

<20 MBMG

USGS

USGS

USGS

.21 USGS

<.10 MBMG

USGS

.24 USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<.20 MBMG

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<.20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

Analyzing 

agency

MBMG

MBMG

MBMG

UM

MBMG

UM

UM

UM

MBMG

MBMG

UM

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

NWQL

MBMG

MBMG

MBMG

UM

UM

UM

UM

UM

UM

MBMG

UM

UM

UM

UM

UM

MBMG

MBMG

MBMG

MBMQ

MBMG

MBMG

MBMG

UM

UM

UM

MBMG

MBMG

MBMG

MBMG

MBMG

NWQL

MBMG

Location 

number

06N21W27BABA01

06N21W27BBAA01

06N21W34ABCD01

06N20W01BABB01

06N20W01CDCD01

06N20W02AADC01

06N20W02BBDA01

06N20W02CCAA01

06N20W02DCDC01

06N20W03BDBB01

06N20W03BDCC01

06N20W03CCDB01

06N20W04AABC01

06N20W04ACCD01

06N20W04ADCD01

06N20W04CCCD01

06N20W04DCCB01

TABLE 6 99
Table 6. Physical properties and major-ion concentrations for water from wells (Continued)

Location 

number

06N20W09BDDD01

06N20W09CBCC01

06N20W09CCDB01

06N20W09DCAB01

06N20W10AADC01

06N20W10ABDB01

06N20W10BCAC01

06N20W10CACB01

06N20W10DADD01

06N20W10DBBB01

06N20W10DCAB01

06N20W11CCBO01

06N20W11DBAA01

06N20W12ABDB01

06N20W12CCCD01

06N20W13BADD01

06N20W13BCAC01

06N20W14ACDD01

06N20W14BADB01

06N20W14BBBB01

06N20W14CAAA01

06N20W14CDAB01

06N20W14DAAA01

06N20W15AACD01

Date

06-24-97

08-19-97

10-15-97

07-27-95

08-15-95

05-03-95

06-15-95

07-14-95

09-14-95

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-14-97

06-15-95

07-14-95

07-14-952

09-14-95

06-15-95

06-15-952

07-27-95

07-27-95

07-27-95

06-15-95

06-15-95

06-15-95

06-15-95

09-08-95

09-08-952

01-07-97

02-26-97

04-03-97

05-20-97

06-24-97

08-19-97

10-15-97

10-15-972

06-15-95

07-14-95

06-15-95

09-07-95

05-02-95

07-30-79

08-28-79

07-14-95

08-05-95

08-24-95

08-24-952

09-07-95

06-15-95

Specific 

conductance, 

field

(uS/cm)

421

404

-

595

332

375

588

775

773

-

774

774

753

747

766

-

419

429

429

465

600

600

420

411

384

598

582

232

750

618

618

638

620

604

-

510

556

-

-

864

637

578

581

440

350

330

248

555

517

517

540

580

pH, 

field 

(standard 

units)

-

-

-

7.4

7.5

7.5

7.2

7.6

7.5

-

-

~

-

-

-

-

8.0

7.8

7.8

7.6

7.9

7.9

7.7

7.9

8.0

7.8

7.5

7.8

7.6

7.9

7.9

-

-

-

-

-

-

-

-

7.3

7.6

7.6

7.7

7.5

-

-

7.3

7.5

8.1

8.1

7.6

7.6

Temper- °^en' Cal- Magne- disature, , , cium sium 

solved, , , water - , . (mg/L as (mg/L as

<°C> , ^ Ca> M§> (mg/L)

12.2

12.4

-

12.0

13.0

12.5

12.0

12.5

11.0 2.0 110 20

9.6

9.5

10.0

10.3

10.2

10.8

..

10.0

12.0

12.0

11.5 9.0 50 7.3

13.0

13.0

13.0

12.0

10.5

12.5

11.5

11.0

11.5

10.5 5.7 75 15

10.5 5.7 74 15

10.2

10.4

10.7

..

10.7

10.3

-

12.0

12.5

9.5

11.5 7.3 29 6.1

11.0

18.5 - 68 12

13.0 - 73 12

10.0

14.5

18.0

18.0

11.0 7.9 47 9.2

12.0

_ .. Potas- Bicar- Carbon- Sodium . i « sium bonate ate

~: (mg/L as (mg/L as (mg/L as

1^*U ts\ US~if\ \ f**f\ \

K) HCOj) *--^'3)

-

..

..

-

..

-

28 7.0 495 0

..

-

-

..

..

..

..

..

..

43 4.6 265 0

_

..

..

..

..

..

..

..

47 2.3 385 0

47 2.2 385 0

..

..

..

..

_

..

100 3.8 355 0

..

21 4.4

20 5.1

..

65 4.3 310 0

100 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Alkalinity1 

(mg/L as 

CaCO3)

--

--

--

-

-

--

--

--

406

-

-

--

--

-

--

--

--

--

--

217

--

--

--

--

--

--

--

--

--

315

315

--

--

-

--

--

--

--

--

--

--

--

291

--

-

--

--

--

--

--

254

--

Sulfate 

(mg/L as 

S04)

7.0

5.0

5.9

49.0

5.5

6.1

33.0

13.0

12

12.0

12.0

11.0

10.0

8.9

9.9

11.0

5.4

7.4

7.6

12

49.0

47.0

10.0

9.6

7.0

56.0

21.0

3.0

26.0

17

17

20.0

17.0

17.0

20.0

14.0

12.0

15.0

14.0

26.0

38.0

15.0

15

9.7

20

18

<2.0

18.0

20.0

20.0

25

25.0

Chloride Fluoride Silica 

(mg/L (mg/L as (mg/L 

as Cl) F) as SiO2)

5.0

3.3

3.5

19.0

2.4

2.6

19.0

3.8

4.5 .20 56

2.9

3.8

3.6

3.2

31

3.8

35

1.6

2.5

25

5.0 .40 54

3.2

3.4

1 .2

1.9

2.5

26.0

6.9

1.1

4.4

6.0 .70 32

6.0 .70 33

6.7

7.0

7.0

7.6

5.4

7.3

7.2

<10

10.0

13.0

6.4

5.5 .50 56

1.5

10 .37 59

10 .31 57

<1.0

6.8

4.4

4.4

6.0 .40 55

8.7

Dissolved 

solids, Nitrate 

calcu- (mg/L as 

lated N) 

(mg/L)

.79

2.0

1.6

4.2

.62

1.1

3.3

2.0

497 2.5

1.7

1.7

1.4

1.3

1.7

1.8

1.8

1.1

1.6

1.6

317 2.3

3.1

3.1

.82

1.5

2.7

1.8

1.7

.2

2.0

394 2.0

394 2.0

2.4

2.7

2.0

1.9

1.7

1.4

3.0

3.1

3.2

.84

1.8

399 1.5

.94

.54

.53

.16

1.1

1.0

1.0

373 1.9

1.5

Phosphorus Collecting 

(mg/L as agency 

P)

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<.20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<.20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<.20 USGS

<.20 USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

<20 USGS

USGS

MBMG

MBMG

USGS

USGS

USGS

USGS

<.20 USGS

USGS

Analyzing 

agency

MBMG

MBMG

MBMG

UM

UM

UM

UM

UM

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

UM

UM

UM

MBMG

UM

UM

UM

UM

UM

UM

UM

UM

UM

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

UM

UM

UM

MBMG

UM

MBMG

MBMG

UM

UM

UM

UM

MBMG

UM

Location 

number

06N20W09BDDD01

06N20W09CBCC01

06N20W09CCDB01

06N20W09DCAB01

06N20W10AADC01

06N20W10ABDB01

06N20W10BCAC01

06N20W10CACB01

06N20W10DADD01

06N20W10DBBB01

06N20W10DCAB01

06N20W11CCBD01

06N20W11DBAA01

06N20W12ABDB01

06N20W12CCCD01

06N20W13BADD01

06N20W13BCAC01

06N20W14ACDD01

06N20W14BADB01

06N20W14BBBB01

06N20W14CAAA01

06N20W14CDAB01

06N20W14DAAA01

06N20W15AACD01

TABLE 6 101
Table 6. Physical properties and major-ion concentrations for water from wells (Continued)

Location 

number

06N20W15BBCC01

06N20W15CACC01

06N20W16AABD01

06N20W16ACCB01

06N20W16ADCB01

06N20W16BAAD01

06N20W16DDDB01

06N20W17AACA01

06N20W17ADCC01

06N20W29BADB01

06N19W06CBCA01

06N19W07BABC01

05N21W03ACBA01

05N21W12BCAB01

05N21W15AABD01

05N21W15AADB01

05N21W22CDAD01

05N21W23BBAA01

05N21W27DDBD01

05N21W36DCC02

05N20W10BAAC01

05N20W17BADC01

05N20W17CBAB01

05N20W17CDDB01

05N20W18ABDA01

05N20W18ADBA01

05N20W18CACC01

05N20W18DACA01

05N20W18DBAA01

05N20W18DCDB01

05N20W30BDCD01

04N21W14CBAA01

04N21W16DDDD01

Date

06-15-95

06-1 5-952

07-27-95

08-15-95

09-14-95

05-02-95

07-27-95

09-07-95

06-15-95

09-07-95

06-15-95

06-15-95

05-02-95

03-09-94

08-24-95

07-27-95

07-27-95

07-27-952

09-14-95

09-14-952

08-15-95

08-15-95

08-18-92

12-14-95

08-18-92

12-14-95

08-15-95

08-15-95

08-15-952

08-15-95

08-20-92

06-06-96

06-06-962

08-18-92

12-14-95

08-15-95

08-15-95

08-25-95

08-15-95

08-15-95

08-18-92

12-14-95

08-15-95

08-1 5-952

08-15-95

08-15-95

03-09-94

12-14-95

08-19-92

12-13-95

08-20-92

12-13-95

Specific 

conductance, 

field

(uS/cm)

481

481

505

526

523

484

577

563

364

353

453

284

307

402

409

739

391

391

429

429

106

42.1

172

158

36.0

40.3

95.8

40.0

40.0

108

115

102

102

630

622

424

427

435

426

415

237

244

310

310

288

243

181

188

254

284

70.0

70.4

pH, 

field 

(standard 

units)

7.5

7.5

7.5

7.5

7.3

7.5

7.5

7.6

7.5

7.5

7.5

6.9

7.2

7.3

7.7

6.9

7.6

7.6

7.3

7.3

6.3

6.4

8.5

8.0

6.1

6.7

7.3

-

-

6.6

6.2

6.4

6.4

7.7

7.9

7.8

4.1

8.0

7.6

7.5

7.1

7.2

7.8

7.8

7.6

7.7

6.9

6.7

6.6

6.8

6.2

6.8

Temperature, 

water 

(°C)

11.5

11.5

11.5

15.0

11.5

11.5

14.5

12.5

10.0

12.5

9.5

10.0

10.5

11.0

12.5

14.5

12.0

12.0

11.5

11.5

9.0

11.0

-

11.0

10.5

7.5

13.5

11.5

11.5

11.5

9.5

7.5

7.5

10.5

9.0

13.5

15.0

11.0

14.5

13.5

12.0

10.0

12.5

12.5

11.5

13.0

9.5

10.0

11.5

10.0

11.5

10.0

Oxygen, Ca,

discium solved, , field (mf; as

(rng/L) Ca)

..

..

7.0 71

_

6.7 70

..

8.8 42

..

..

..

64

..

-

7.8 64

7.8 62

..

..

.7 3.5

..

7.2 2.7

..

..

-

..

1.4 7.5

..

7.5 45

..

..

..

..

8.2 28

..

..

..

23

-

6.9 33

..

6.0 5.9

Magnesium 

(mg/L as 

Mg)

-

-

-

-

13

-

-

12

-

7.9

-

-

-

9.1

-

-

-

-

7.6

7.6

-

-

3.9

-

.9

-

-

-

-

-

2.0

-

-

13

-

-

-

-

-

-

6.2

-

-

-

4.3

-

7.6

-

1.5

Sodium 

(mg/L as 

Na)

-

-

-

-

22

-

-

40

-

19

-

-

--

6.7

-

-

-

-

17

18

-

-

28

-

2.3

-

-

-

-

11

-

78

-

-

-

-

10

-

-

6.6

6.8

5.5

..

Potassium 

(mg/L as 

K)

-

-

-

-

3.7

-

-

3.1

-

2.8

-

-

~

3.3

-

-

-

-

3.7

3.7

-

-

1.3

-

.70

-

-

-

-

1.1

-

3.6

-

-

-

..

_

1.9

-

..

..

-

2.2

_

3.4

..

.40

..

Bicarbonate1 

(mg/L as 

HC03)

-

-

--

~

287

~

~

342

-

156

-

-

~

-

-

-

-

-

243

243

-

-

95

-

17

-

-

-

-

53

..

-

374

-

-

140

-

..

..

-

..

144

..

39

Carbonate1 

(mg/L as 

C03)

-

-

-

--

0

-

-

0

-

0

-

-

-

-

-

-

-

-

0

0

-

4

-

0

-

-

-

-

-

0

-

0

-

-

-

0

-

..

..

0

..

0

_

102 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Alkalinity 1 

(mg/Las 

CaCO3)

-

-

--

-

235

-

--

280

--

128

-

-

--

-

-

--

-

--

199

199

--

-

84

-

14

--

--

--

--

-

43

--

--

307

--

--

-

--

--

-

115

--

-

--

--

-

-

-

118

--

32

-

Sulfate 

(mg/Las 

S04)

6.1

6.5

16.0

22.0

23

24.0

13.0

12

20.0

17

17.0

5.5

4.0

3.3

6.0

42.0

12.0

11.0

17

17

2.5

<2.0

3.1

<2.0

1.0

<2.0

<2.0

<2.0

<2.0

<2.0

1.5

2.0

2.1

30

31.0

8.7

16.0

21.0

10.0

10.0

3.7

2.8

<2.0

<2.0

3.5

3.6

4.6

6.5

4.8

5.6

1.0

<2.0

Chloride Fluoride 

(mg/L (mg/L as 

as Cl) F)

4.3

4.7

7.0

13.0

14 .20

28.0

6.1

5.5 .40

17.0

19 .40

14.0

3.7

<1.0

1.4 .11

2.1

27.0

2.8

2.5

5.0 .80

5.0 .90

1.3

< 1.0

.40 .30

1.3

.10 <10

<1.0

< 1.0

< 1.0

<1.0

1.7

7.6 <10

2.1

2.1

.70 1.5

2.9

4.0

11.0

24.0

7.3

7.4

.70 .40

1.3

<1.0

<1.0

2.5

2.0

1.4 .23

1.9

.30 .20

1.2

.20 <10

< 1.0

Silica 

(mg/L 

as SiO2)

--

-

-

-

41

-

-

49

-

55

-

-

-

31

-

-

-

-

48

49

-

-

38

19

-

--

-

-

-

25

-

-

44

-

-

-

-

-

-

31

-

-

-

-

-

37

-

35

~

43

-

Dissolved 

solids, 

calculated 

(mg/L)

--

-

-

-

336

-

-

368

-

247

-

--

--

--

--

-

--

--

285

286

-

-

130

35

-

-

-

-

-

83

-

-

400

-

-

-

-

-

-

151

-

-

-

-

-

--

-

162

-

77

-

Nitrate 

(mg/Las

N)

1.4

1.6

1.0

1.3

1.6

1.4

1.5

1.5

<15

1.4

1.6

.92

1.0

1.3

1.3

1.7

.75

.77

.40

.50

.15

<15

-

<15

--

<15

<15

.15

<15

.28

-

.22

.22

-

.45

.52

.73

1.2

1.2

1.1

-

.38

.25

.27

.94

.63

2.2

3.7

-

2.3

--

.5

Phosphorus 

(mg/Las 

P)

-

-

-

-

<20

-

-

<.20

-

<20

-

--

-

<.20

-

-

-

-

<.20

<.20

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

--

-

-

-

-

-

.20

-

-

-

-

Collecting 

agency

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

MBMG

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

MBMG

USGS

USGS

USGS

USGS

USGS

Analyzing 

agency

UM

UM

UM

UM

MBMG

UM

UM

MBMG

UM

MBMG

UM

UM

UM

MBMG

UM

UM

UM

UM

MBMG

MBMG

UM

UM

NWQL

UM

NWQL

UM

UM

UM

UM

UM

NWQL

UM

UM

NWQL

UM

UM

UM

UM

UM

UM

NWQL

UM

UM

UM

UM

UM

MBMG

UM

NWQL

UM

NWQL

UM

Location 

number

06N20W15BBCC01

06N20W15CACC01

06N20W16AABD01

06N20W16ACCB01

06N20W16ADCB01

06N20W16BAAD01

06N20W16DDDB01

06N20W17AACA01

06N20W17ADCC01

06N20W29BADB01

06N19W06CBCA01

06N19W07BABC01

05N21W03ACBA01

05N21W12BCAB01

05N21W15AABD01

05N21W15AADB01

05N21W22CDAD01

05N21W23BBAA01

05N21W27DDBD01

05N21W36DCC02

05N20W10BAAC01

05N20W17BADC01

05N20W17CBAB01

05N20W17CDDB01

05N20W18ABDA01

05N20W18ADBA01

05N20W18CACC01

05N20W18DACA01

05N20W18DBAA01

05N20W18DCDB01

05N20W30BDCD01

04N21W14CBAA01

04N21W16DDDD01

TABLE 6 103
Table 6. Physical properties and major-ion concentrations for water from wells (Continued)

Location 

number

04N21W35CCBA01

03N21W14BBAC01

03N21W15CCCD01

02N21W01CACD01

02N20W07BCCC01

02N20W07CABC01

Date

08-19-92

08-19-92

08-19-92

06-06-96

12-13-95

12-13-952

08-19-92

12-13-95

Specific 

conductance, 

field

(jiS/cm)

156

159

148

151

215

215

54.0

69.9

pH, 

field 

(standard 

units)

6.7

6.5

6.5

6.8

7.0

7.&

6.8

6.8

Temperature, 

water

(°Q

10.5

10.5

9.5

9.5

9.5

9.5

11.0

9.0

Oxygen, 

dissolved, 

field 

(mg/L)

4.8

4.3

6.0

-

-

-

7.4

--

Calcium 

(mg/L as 

Ca)

16

14

15

-

-

-

5.6

-

Magnesium 

(mg/L as 

Mg)

5.6

2.7

3.5

-

-

-

1.2

-

Sodium 

(mg/L as 

Na)

6.5

16

11

-

-

-

2.2

-

Potassium 

(mg/L as 

K)

1.8

1.4

.50

-

-

-

1.4

--

Bicarbonate1 

(mg/L as 

HCO3)

92

98

84

-

-

-

28

--

Carbonate1 

(mg/L as 

C03)

0

0

0

~

-

-

0

-

'Field incremental titration for samples collected by USGS. Laboratory fixed-end titration for samples collected by MBMG 

2Replicate analyses.

104 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Unity1 

(mg/Las 

CaCO3)

76

80

69

-

--

--

23

--

Sulfate 

(mg/L as 

S04)

2.0

2.5

1.4

<2.0

<2.0

<2.0

1.5

2.6

Chloride 

(mg/L 

asCl)

.60

.70

1.2

1.9

1.3

<1.0

.40

1.0

Fluoride 

(mg/Las 

F)

.20

.10

<.10

--

-

--

.10

-

Silica 

(mg/L 

as SiO2)

29

26

41

-

--

-

13

-

Dissolved

solids, 

calculated 

(mg/L)

107

112

115

-

--

--

40

--

Nitrate 

(mg/Las

N)

--

-

-

.69

.18

.16

-

.43

Phosphorus 

(mg/Las 

P)

--

-

--

-

-

-

--

-

Collecting 

agency

uses

uses

uses

uses

uses

uses

uses

uses

Analyzing 

agency

NWQL

NWQL

NWQL

UM

UM

UM

NWQL

UM

Location 

number

04N21W35CCBA01

03N21W14BBAC01

03N21W15CCCD01

02N21W01CACD01

02N20W07BCCC01

02N20W07CABC01

TABLE 6 105
Table 7. Trace-element and radon concentrations for water from wells

[Location number numbering system described in text. Constituents are dissolved, except as indicated. Collecting agency: MBMG, Montana Bureau of 

Mines and Geology, Butte, Mont.; USGS, U.S. Geological Survey, Helena, Mont. Analyzing agency: MBMG, Montana Bureau of Mines and Geology, 

Analytical Division, Butte, Mont.; NWQL, USGS National Water Quality Laboratory, Arvada, Colo. Abbreviations: jlg/L, micrograms per liter; pCi/L, 

picocuries per liter. Symbols: <, less than; --, no data]

Location number

10N20W10ACBC01

10N20W10CBBD01

10N20W11CDCD01

10N20W12ADCB01

10N20W12DDDC01

10N20W13BBA01

10N19W05DCDD01

10N19W06DCDA01

10N19W06DDCC01

10N19W07ADBC01

10N19W07BACB01

10N19W07CAAB01

10N19W07CDCC01

10N19W08ADDC01

10N19W08BCAD01

10N19W08CDAC01

10N19W08DBBD01

10N19W08DCCB01

10N19W08DCCC02

10N19W16BBBC01

10N19W18AADB01

10N19W18DBBA01

09N20W20CDCD01

08N21W27DCBC01

08N20W01DAAD01

08N20W14ABDB01

08N20W23CDDD01

08N20W26BAAC01

08N19W04BDAA01

08N19W07CBBD01

08N19W11CDBB01

07N21W13BBAD01

07N21W25CABC01

07N21W36DDDC01

07N20W32DDDA02

06N21W02ABBD01

06N21W03DDAA01

06N21W09DADA01

Date

06-23-80

03-10-94

03-10-94

09-13-95

09-15-95

05-12-80

09-12-95

09-12-95

09-19-95

09-13-95

09-13-95 1

09-12-95

09-15-95

09-13-95

09-12-95

09-13-95

09-13-95

09-12-95

09-13-95

03-10-94

09-15-95

09-13-95

09-13-95

09-14-95

03-10-94

08-20-92

09-15-95

08-20-92

03-10-94

03-09-94

03-10-94

08-20-92

08-17-92

08-1 7-92 '

08-17-92

03-09-94

03-09-94

03-09-94

09-07-95

09-07-95

Aluminum

as 

Al)

-

<30

<30

<30

<30

..

<30

<30

-

<30

<30

<30

<30

<30

<30

<30

<30

<30

<30

<30

<30

<30

<30

<30

160

..

<30

-

<30

<30

<30

-

-

-

<30

<30

<30

30

<30

Arsenic,

As+3 

and

Gig/Las 

As)

-

<1

<1

<1

2

<1

1

-

<1

<1

<1

<1

<1

4

<1

<1

5

<1

<J

2

<1

<1

<1

<J

..

3

-

<1

<>

2

-

..

-

<1

3

<1

<1

<1

Barium

Oig/Las 

Ba)

-

3

71

77

110

190

140

-

98

100

110

76

92

130

100

100

140

97

100

60

73

80

11

21

55

140

40

27

31

55

37

7

7

23

7

64

6

48

42

Beryllium

(Hg/Las 

Be)

-

<2

<2

<2

<2

<2

-

-

<2

..

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<. 5

<2

<5

<2

<2

<2

<5

<.5

<.5

<-5

<2

<2

<2

<2

<2

Boron

(ug/L 

as B)

-

<30

<30

<30

<30

..

<80

<30

-

<80

<30

<30

<30

<30

<30

<80

<80

<80

<30

<30

<30

<30

<30

<30

<30

40

<30

20

<30

<30

220

10

<10

<10

<10

<30

<30

<30

<80

130

Cadmium

as Cd)

-

<2

<2

<2

<2

<2

<2

-

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

5

<2

2

<2

<2

<2

1

1

2

2

<2

<2

<2

<2

<2

Chromium

asCr)

-

<2

<2

<2

<2

..

<2

<2

-

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<5

<2

<5

<2

<2

<2

<5

<5

<5

<5

<2

<2

<2

3

4

Copper

as Cu)

-

47

<2

<2

<2

..

<2

<2

-

<2

<2

<2

<2

<2

<2

<2

5

3

<2

32

<2

<2

36

<2

<2

<10

3

<10

<2

<2

2

<10

<10

<10

<10

11

<2

4

12

<2

Iron

Oig/L 

as Fe)

<10

3

450

4

<3

160

<3

<3

~

12

5

<3

4

<3

6

270

<3

<3

<3

<3

6

<3

<3

200

150

4

<3

18

12

42

<2

38

<3

<3

160

13

4

3

39

<10

Lead

(jig/Las 

Pb)

-

<2

<2

<2

<2

<2

<2

-

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<10

<2

10

<2

<2

<2

<10

<10

<10

<10

<2

<2

<2

<2

<2

Lithium

as Li)

-

<6

<6

<6

<6

-.

6

<6

-

<6

<6

<6

<6

<6

<6

23

<6

7

<6

<6

<6

<6

<6

<6

11

<4

8

7

14

<6

7

10

<4

<4

9

7

10

14

10

58

Manganese

Oig/Las 

Mn)

<10

<2

51

<2

<2

<10

<2

<2

-

3

<2

<2

<2

<2

15

32

<2

4

<2

2

<2

<2

<2

6

<2

<1

<2

3

130

<2

<2

1

<1

<1

16

<2

<2

<2

<2

20

106 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Molyb- ... 

. Nickel denum

°lg/LaS as NO 

Mo) aSN °

..

<10 <2

<10 <2

<10 <2

<10 <2

..

<10 2

<10 <2

..

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <10

<10 <2

<10 <10

<10 <2

<10 <2

<10 <2

<10 <10

<10 <10

<10 <10

<10 <10

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

Sele- _., Stron- Tita- Silver 

mum hum mum

. (ug/Las . _ , (ug/Las vr° (ug/Las (ug/L

Se) g' Sr) asTi)

_

<1 <1 24 <10

<1 <1 120 <10

<1 <1 74 <10

<1 <1 72 <10

_

2 <1 270 <10

<1 <1 110 <10

..

<1 <1 73 <10

<1 <1 72 <10

<1 <1 69 <10

<1 <1 47 <10

<1 <1 66 <10

<1 <1 110 <10

1 <1 110 <10

<1 <1 61 <10

2 <1 61 <10

<1 <1 48 <10

<1 <1 49 <10

<1 <1 40 <10

<1 <1 33 <10

<1 <1 35 <10

<1 <1 160 <10

<1 <1 89 <10

<1 290

<1 <1 200 <10

1 85

<1 <1 180 <10

<1 <1 41 <10

<1 <1 360 <10

<1 54

<1 120

<1 120

<1 87

< <1 43 <10

< <1 130 <10

< <1 110 <10

< <1 150 <10

< <1 730 <10

Vanadium

asV)

-

<5

<5

<5

<5

<5

<5

-

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<6

<5

<6

<5

<5

<5

<6

<6

<6

<6

<5

<5

<5

<5

<5

Zinc

(ug/Las 

Zn)

-

17

61

15

<8

..

8

15

-

120

130

13

13

24

430

200

77

<8

15

490

180

18

<8

<8

16

180

120

120

18

25

34

36

21

24

17

220

25

7

19

43

Zirconium

(Ug/Las 

Zr)

-

<20

<20

<20

<20

..

<20

<20

-

<20

<20

<20

<20

<20

<20

<20

<20

<20

<20

<20

<20

<20

<20

<20

29

..

<20

--

<20

<20

<20

--

--

--

--

<20

<20

<20

<20

<20

Radon 

222, total 

(pCi/L)

-

-

-

1,080

580

..

1,080

-

880

1,070

500

760

410

--

710

510

810

550

--

650

810

660

-

-

-

-

-

-

_

-

3,600

-

1,800

..

-

-

1,950

1,280

Collecting 

agency

MBMG

MBMG

MBMG

USGS

USGS

MBMG

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

MBMG

USGS

USGS

USGS

USGS

MBMG

USGS

USGS

USGS

MBMG

MBMG

MBMG

USGS

USGS

USGS

USGS

MBMG

MBMG

MBMG

USGS

USGS

Analyzing agency

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

NWQL

MBMG

NWQL

MBMG

MBMG

MBMG

NWQL

NWQL

NWQL

NWQL

MBMG

MBMG

MBMG

MBMG

MBMG

Location number

10N20W10ACBC01

10N20W10CBBD01

10N20W11CDCD01

10N20W12ADCB01

10N20W12DDDC01

10N20W13BBA 01

10N19W05DCDD01

10N19W06DCDA01

10N19W06DDCC01

10N19W07ADBC01

10N19W07BACB01

10N19W07CAAB01

10N19W07CDCC01

10N19W08ADDC01

10N19W08BCAD01

10N19W08CDAC01

10N19W08DBBD01

10N19W08DCCB01

10N19W08DCCC02

10N19W16BBBC01

10N19W18AADB01

10N19W18DBBA01

09N20W20CDCD01

08N21W27DCBC01

08N20W01DAAD01

08N20W14ABDB01

08N20W23CDDD01

08N20W26BAAC01

08N19W04BDAA01

08N19W07CBBD01

08N19W11CDBB01

07N21W13BBAD01

07N21W25CABC01

07N21W36DDDC01

07N20W32DDDA02

06N21W02ABBD01

06N21W03DDAA01

06N21W09DADA01

TABLE 7 107
Table 7. Trace-element and radon concentrations for water from wells (Continued)

Location number

06N21W11ABAA01

06N21W11CDCB01

06N21W12BDDD01

06N21W14BDAC01

06N21W15CDDD01

06N21W22AADC01

06N21W23CABC01

06N21W23DDAD01

06N21W23DDBB01

06N21W24BAAC01

06N21W24CCAC01

06N21W25DBAA01

06N21W26DBAD01

06N21W27BBAA01

06N20W01BABB01

06N20W01CDCD01

06N20W03BDCC01

06N20W04DCCB01

06N20W10AADC01

06N20W10BCAC01

06N20W12CCCD01

06N20W14ACDD01

06N20W14BBBB01

06N20W14DAAA01

06N20W16AABD01

06N20W16ADCB01

06N20W16BAAD01

06N20W29BADB01

06N20W30DBCC01

06N19W07BABC01

05N21W15AABD01

05N21W15AADB01

05N21W36DCC02

05N20W10BAAC01

05N20W18CACC01

05N20W30BDCD01

04N21W14CBAA01

04N21W16DDDD01

04N21W35CCBA01

03N21W14BBAC01

03N21W14CAAA01

03N21W15CCCD01

02N20W07BCCC01

Date

09-06-95

09-06-95

09-06-95

09-06-95

09-06-95 '

08-17-92

09-06-95

09-06-95

09-05-95

09-05-95

09-06-95

09-05-95

08-18-92

03-08-94

03-08-94

09-14-95

09-07-95

03-09-94

09-14-95

09-14-95

09-14-95

09-08-95

09-08-95 '

09-07-95

07-30-79

08-28-79

09-07-95

09-14-95

09-07-95

09-07-95

03-09-94

09-19-92

09-14-95

09-14-95 1

08-18-92

08-18-92

08-20-92

08-18-92

08-18-92

03-09-94

08-19-92

08-20-92

08-19-92

08-19-92

09-19-92

09-19-92

08-19-92

08-19-92

Aluminum

(Hg/L 

as 

Al)

<30

<30

60

40

40

..

60

<30

190

190

<30

160

-

<30

<30

<30

<30

<30

<80

<30

<30

<30

<30

<30

--

<30

<30

<30

<30

<30

-

<30

<30

-

..

-

-

-

<30

-

-

-

-

..

-

-

Arsenic,

As+3 

and

As+s 

(Hg/Las 

As)

<1

1

<1

<1

<1

..

<1

<1

<1

<1

<1

<1

-

<1

<1

12

11

4

8

9

7

9

9

11

-

..

8

2

4

5

2

-

5

5

--

..

-

-

-

<1

-

-

-

-

__

-

--

Barium

(jjg/Las 

Ba)

67

57

53

6

6

3

7

12

10

13

14

6

32

17

10

24

35

55

64

180

120

79

78

79

-

..

64

95

120

69

83

-

71

71

9

3

22

42

54

29

46

11

44

13

-

9

6

Beryllium

Oig/Las 

Be)

<2

<2

<2

<2

<2

<.5

<2

<2

<2

<2

<2

<2

<5

<2

<2

<2

<2

<2

-

<2

<2

<2

<2

<2

--

_

<2

<2

<2

<2

<2

-

<2

<2

<.5

<5

<.5

<.5

<.5

<2

<.5

<.5

<.5

<.5

-

_

<.5

<.5

Boron

(Hg/L 

as B)

<80

<80

<80

<80

<80

<10

<80

<80

<80

<80

<80

<80

<10

<30

<30

120

<80

<30

<80

80

90

80

<80

200

-

..

170

<30

80

<80

<30

_

80

90

10

<10

<10

<10

<10

<30

10

<10

100

10

-

_

<10

<10

Cadmium

(Hg/L 

as Cd)

<2

<2

<2

<2

<2

<1

<2

<2

<2

<2

<2

<2

3

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

-

_

<2

<2

<2

<2

<2

-

<2

<2

3

3

1

<1

2

<2

2

2

2

3

--

3

2

Chromium

(Hg/L 

asCr)

<2

<2

<2

<2

<2

<5

<2

<2

<2

<2

<2

<2

<5

<2

<2

<2

8

<2

<2

6

<2

8

7

7

--

..

6

<2

7

4

<2

-

<2

<2

<5

<5

<5

<5

<5

<2

<5

<5

<5

<5

--

_

<5

<5

Copper 

(Hg/L 

as Cu)

<2

<2

<2

<2

<2

<10

4

7

4

2

<2

6

<10

<2

<2

<2

4

3

<2

2

<2

<2

<2

<2

~

..

<2

<2

7

4

<2

-

<2

<2

<10

<10

<10

<10

<10

5

<10

<10

<10

<10

--

__

<10

<10

Iron

(Hg/L 

as Fe)

1,000

1,400

1,200

15

16

6

170

<10

300

280

250

230

<3

91

45

5

11

4

8

4

<3

<5

<5

6

30

<0

<5

<3

<3

<10

<2

-

5

6

45

39

1,200

<3

40

4

<3

4

4

<3

-

..

5

29

Lead

(fig/Las 

Pb)

<2

<2

<2

<2

<2

<10

<2

<2

<2

<2

<2

<2

<10

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

-

..

<2

<2

<2

<2

<2

-

<2

<2

<10

<10

<10

<10

20

<2

<10

<10

<10

<10

--

__

<10

<10

Lithium

(Hg/L 

as Li)

<6

25

6

8

<6

<4

9

11

12

12

9

6

<4

12

9

14

10

10

9

12

7

10

<10

21

10

9

13

<6

12

10

<6

-

9

11

28

<4

8

12

6

18

13

9

12

17

--

_

9

<4

Manganese

((ig/Las 

Mn)

120

39

54

<2

<2

<1

3

<2

6

6

6

4

<1

10

8

<2

<2

<2

<2

<2

<2

<2

<2

<2

<10

<0

<2

<2

<2

<2

<2

-

<2

<2

290

20

76

<1

14

<2

1

<1

<1

<1

-

_

2

23

Replicate analyses.

108 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Molyb- .... , , 

, Nickel denum

(Mg/LaS as NO Mo) aSWO

<10 <2 

<10 <2 

<10 <2

<10 <2

<10 ,2

<10 <10

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <2

<10 <10

<10 <2

<10 <2

<10 <2

<10 <2

<10 2

<10 <2

<10 3

<10 <2

<10 2

<10 2

11 <2

-

12 <2

<10 <2

<10 <2

<10 <2

<10 2

..

<10 <2

<10 <2

<10 <10

<10 <10

<10 <10

<10 <10

<10 <10

<10 <2

<10 <10

<10 <10

<10 <10

<10 <10

-

<10 <10

<10 <10

Sele- .,., Stron- Tita- Silver 

mum tium mum

. (Hg/Las , , (jig/Las "T (ng/Las (jig/L

Se) 8) Sr) asTi)

<1 < 120 <10 

<1 < 130 <10 

<1 < 170 <10

<1 < 85 <10

<1 < 84 <10

1 54

<1 <1 45 20

<1 <1 84 <10

<1 <1 64 20

<1 <1 68 20

<1 <1 120 <10

<1 <1 74 20

<1 55

<1 <1 140 <10

<1 <1 170 <10

1 <1 120 <10

<1 <1 140 <10

<1 <1 100 <10

<1 <1 26 <10

1 <1 260 <10

<1 <1 120 <10

<1 <1 140 <10

<1 <1 140 <10

<1 <1 69 <10

-

<1 <1 83 <10

<1 <1 180 <10

<1 <1 170 <10

1 <1 82 <10

<1 <1 110 <10

..

<1 <1 130 <10

<1 <1 130 <10

<1 120

1 49

<1 90

<1 140

<1 160

<1 <1 210 <10

<1 210

2 76

<1 180

<1 160

-

-

<1 150

<1 46

Vanadium

asV)

<5 

<5 

<5

<5

<5

<6

<5

<5

<5

<5

<5

<5

<6

<5

<5

15

28

<5

14

7

<5

15

14

17

-

..

14

<5

9

9

<5

-

<5

<5

<6

<6

<6

14

7

<5

7

<6

<6

<6

--

<6

<6

Zinc

(jag/Las 

Zn)

28 

69 

6

8

8

27

32

<2

3

18

3

9

7

17

6

110

42

12

26

91

32

26

27

43

-

2

<8

23

74

13

-

80

83

<3

280

24

16

16

7

80

8

34

4

--

14

530

Zirconium

(fig/Las 

Zr)

<20 

<20 

<20

<20

<20

..

<20

<20

<20

<20

<20

<20

-

<20

<20

<20

<20

<20

<20

<20

<20

<20

<20

<20

--

..

<20

<20

<20

<20

<20

-

<20

<20

--

-

-

-

-

<20

--

-

--

--

-

--

Radon 

222, total 

(pCi/L)

--

-

-

1,600

1,100

1,120

1,130

910

2,720

1,090

1,300

-

--

490

350

-

640

150

..

200

-

-

-

..

170

-

150

230

725

~

-

-

670

-

430

1,400

--

-

-

3,700

1,667

2,423

3,300

-

Collecting 

agency

USGS 

USGS 

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

USGS

MBMG

MBMG

USGS

USGS

MBMG

USGS

USGS

USGS

USGS

USGS

USGS

MBMG

MBMG

USGS

USGS

USGS

USGS

MBMG

MBMG

USGS

USGS

USGS

USGS

USGS

USGS

USGS

MBMG

USGS

USGS

USGS

USGS

MBMG

MBMG

USGS

USGS

Analyzing agency

MBMG 

MBMG 

MBMG

MBMG

MBMG

NWQL

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

NWQL

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

MBMG

NWQL

NWQL

NWQL

NWQL

NWQL

MBMG

NWQL

NWQL

NWQL

NWQL

MBMG

MBMG

NWQL

NWQL

Location number

06N21W11ABAA01 

06N21W11CDCB01 

06N21W12BDDD01

06N21W14BDAC01

06N21W15CDDD01

06N21W22AADC01

06N21W23CABC01

06N21W23DDAD01

06N21W23DDBB01

06N21W24BAAC01

06N21W24CCAC01

06N21W25DBAA01

06N21W26DBAD01

06N21W27BBAA01

06N20W01BABB01

06N20W01CDCD01

06N20W03BDCC01

06N20W04DCCB01

06N20W10AADC01

06N20W10BCAC01

06N20W12CCCD01

06N20W14ACDD01

06N20W14BBBB01

06N20W14DAAA01

06N20W16AABD01

06N20W16ADCB01

06N20W16BAAD01

06N20W29BADB01

06N20W30DBCC01

06N19W07BABC01

05N21W15AABD01

05N21W15AADB01

05N21W36DCC 02

05N20W10BAAC01

05N20W18CACC01

05N20W30BDCD01

04N21W14CBAA01

04N21W16DDDD01

04N21W35CCBA01

03N21W14BBAC01

03N21W14CAAA01

03N21W15CCCD01

02N20W07BCCC01

TABLE 7 109
Table 8. Physical properties and major-ion concentrations for water from surface-water sites and one spring

[Location number: numbering system described in text. Constituents are dissolved, except as indicated. Collecting agency: USGS, U.S. Geological Survey, 

Helena, Mont. Analyzing agency: MBMG, Montana Bureau of Mines and Geology, Analytical Division, Butte, Mont.; UM, University of Montana, 

Missoula, Mont. Abbreviations: |lS/cm, microsiemens per centimeter at 25 °C; °C, degrees Celsius; mg/L, milligrams per liter. Symbols: <, less than; --, no 

data]

Location number

06N21W20AABB01

06N20W12AACD01

06N20W12AACD02

08N20W02ACBD01 2

10N19W03DCCD01

Date

09-20-95

09-20-95

09-20-95

10-26-95

09-20-95

Specific 

conductance, 

field

(uS/cm)

11

34

309

588

157

pH, 

field 

(standard 

units)

6.1

7.1

7.0

7.4

7.7

Temperature, 

water

(°Q

8.5

14.0

9.0

9.5

8.0

Calcium 

(mg/L as 

Ca)

1.4

3.7

52

-

20

Magnesium 

(mg/L as 

Mg)

0.1

.9

6.8

-

6.4

Sodium 

(mg/L as

Na)

0.8

1.2

5.3

-

3.2

Potassium 

(mg/L as 

K)

0.20

.3

2.8

-

1.5

Bicarbonate1 

(mg/L as 

HC03)

6

17

154

-

94

Carbonate1 

(mg/L as 

C03)

0

0

0

-

0

Alkalinity 1 

(mg/L as 

CaC03)

5

14

126

-

77

Sulfate 

(mg/L as 

804)

<2.5

<2.5

5.0

15

5.0

Chloride 

(mg/L 

asCl)

<0.50

.50

1.5

7.2

.50

Fluoride 

(mg/L as 

F)

<0.10

<.10

.30

-

<10

Silica 

(mg/L 

as SiO2)

5.3

5.5

29

-

17

Dissolved 

solids, 

calculated

(mg/L)

-

-

178

-

100

Nitrate 

(mg/L as

N)

<0.05

<.05

<.05

1.2

.05

Phosphorus 

(mg/L as 

P)

<0.20

<.20

<.20

-

<.20

Collecting 

agency

USGS

USGS

USGS

USGS

USGS

Analyzing 

agency

MBMG

MBMG

MBMG

UM

MBMG

Location number

06N21W20AABB01

06N20W12AACD01

06N20W12AACD02

08N19W02ACBD01 2

10N19W03DCCD01

Field incremental titration. 

2Spring.

110 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 9. Trace-element concentrations for water from surface-water sites

[Location number: Numbering system described in text. Constituents are dissolved, except as indicated. Collecting agency: USGS, U.S. Geological Survey, 

Helena, Mont. Analyzing agency: MBMG, Montana Bureau of Mines and Geology, Analytical Division, Butte, Mont. Abbreviations: Ug/L, micrograms per 

liter. Symbols: <, less than]

Location number

06N21W20AABB01 

06N20W12AACD01

06N20W12AACD02

10N19W03DCCD01

Date

09-20-95 

09-20-95

09-20-95

09-20-95

Aluminum

30 

<30

<30

<30

Arsenic,

As+3 and 

As+5

<]

4

<1

Barium

(ug/Las 

Ba)

4 

14

35

53

Boron

<30 

<30

<30

<30

Cadmium

<2 

<2

<2

<2

Chromium

(ug/L 

asCr)

<2 

<2

<2

<2

Copper 

(Ug/Las 

Cu)

<2 

<2

<2

<2

Iron

(ug/Las 

Fe)

<20 

<20

<20

<20

Lead

(ug/Las 

Pb)

<2 

<2

<2

<2

Lithium

as Li)

<6 

<6

<6

<6

Manganese

(ug/Las 

Mn)

<2 

<2

<2

<2

Molybdenum

(fig/Las 

Mo)

Cp|p_

Nickel . Silver

mum

... . _ , n«i Tita- -- vflnfl~ _. £rii co~ Nickel . Silver . Zinc . _ .. . . .

, _ mum . _ tium mum dium , _ mum Collecting Analyzing . . .

(jig/Las , _ (ug/Las , _ . _ , _ (ug/Las , _ e J 6 Location number \r-\ (ug/L»s A A (Mg/Las (|ig/Las (ug/Las ^* (ug/Las agency agency

ni' c~\ A& C -\ fi) V) Zr)

Strontium

Se) Sr) Ti)

<20 USGS MBMG 06N21W20AABB01

MBMG 06N20W12AACD01

MBMG 06N20W12AACD02

MBMG 10N19W03DCCD01

<2 

<2 

<2 

<2

15

27

100

28

<5 

<5 

<5 

<5

<8

<20 USGS 

<20 USGS 

<20_____USGS

TABLE 9 111
Table 10. Physical properties and major-ion concentrations for deionized-water field blanks

[Location number indicates site where sampling equipment was used prior to collecting field blank. Constituents are dissolved, except as indicated. 

Collecting agency: USGS, U.S. Geological Survey, Helena, Mont. Analyzing agency: MBMG, Montana Bureau of Mines and Geology, Analytical Division, 

Butte, Mont. Abbreviations: uS/cm, microsiemens per centimeter at 25 °C; °C, degrees Celsius; mg/L, milligrams per liter. Symbols: <, less than; , no 

data]

peci ic p , Temper. Oxygen, Cal- Magne- _ .. Potas- Bicar- Carbon-

. conduct- field F .. . ! . . Sodium . . . i ^ i Location number _ . , ature, dissolved, cium sium . sium bonate ate

, . .. Date ance, (stand- _ .. , _ , (mg/L as , , , of previous site // ^ water field (mg/L as (mg/L as ". (mg/L as (mg/L as (mg/L as field ard 0 Na) HCO

(^iS/cm) units) & J

06N20W12CCCD01 09-08-95 ~ ~ ~ ~ ^ol <O1 <O1 O19 ~ ~

10N20W12DDDC01 09-15-95 - - - - <.l <.l <.l <.l

Dis-

^*\ Sulfate Chloride Fluoride Silica w^ Nitrate ^h°S" _ ,. . . . _ rf . , unity / , n , n n solids, . _ phorus Collecting Analyzing Location number of 

, _ (mg/L as (mg/L (mg/L as (mg/L , ' (mg/L as ; _ B J B ... (mg^as * ' » ^L -IJAx calcu- * (mg^as agency agency previous site 

CaC03) S*°4) asCl) * } ass»°2) ,ated N) p)

____________________________________(mga.)____________________________________________ 

~ ^1 <0.50 <0.10 20 ~ <0.05 <0.20 USGS MBMG 06N20W12CCCD01 

-______<2.5______<.5Q______<.1Q_____20______- <.5______<.2Q______USGS______MBMG_____10N20W12DDDC01 

'Field incremental titration.

112 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana
Table 11. Trace-element concentrations for deionized-water field blanks

[Location number indicates site where sampling equipment was used prior to collecting field blank. Constituents are dissolved, except as indicated. 

Collecting agency: USGS, U.S. Geological Survey, Helena, Mont. Analyzing agency: MBMG Montana Bureau of Mines and Geology, Analytical Division, 

Butte, Mont. Abbreviation: |Lig/L, micrograms per liter. Symbol: <, less than]

Location number of 

previous site

06N20W12CCCD01 

10N20W12DDDC01

Date

09-08-95 

09-15-95

Aluminum

(Mg/Las 

Al)

<30 

<30

Arsenic,

As+3 and 

As+s 

(Mg/Las 

As)

<l

Barium

((ig/Las 

Ba)

6

Beryllium

Be)

<2 

<2

Boron 

as B)

<80

<30

Cadmium

as Cd)

<2 

<2

Chromium

asCr)

<2 

<2

Copper

(fig/Las 

Cu)

<2 

<2

Iron

(jug/Las 

Fe)

<3

Lead 

Pb)

<2 

<2

Lithium

as Li)

<6 

<6

Molyb- ... Sele- Stron- Tita- Vana- . Zirco-

. Nickel Silver . ... Zinc . _ ,. ... , ^ ,_ denum mum tium mum dium , mum Collecting Analzing Location number

, _ (Wg/L (ug/Las , . . . (ug/Las . . . .. (^ig/Las T,.v ~T , (^ig/Las (pg/Las (^ig/L (|ig/L ^* (^g/Las agency agency of previous site

Mo) asNl) Ag) Se) Sr) asTi) asV) Zn) Zr) _____ ^^

<10 <2 <1 <I <6 <10 ^5 ^ ^0 USGS MBMG 06N20W12CCCD01

<10 <2 <1 <1 <6 <10 <5 <8 <20 USGS MBMG 10N20W12DDDC01

Manganese

(ug/L (ug/Las ~ °.x - x

». v ». x asNi) Ag) asMn) Mo) ' s/

<2 <10

<2

TABLE 11 113
Table 12. Drinking-water regulations and guidelines for public water supply1 '2

[MCL, Maximum Contaminant Level; SMCL, Secondary Maximum Contaminant Level; mg/L, milligrams per liter; Hg/L, micrograms 

per liter; , no regulation available or not applicable]

Maximum concentration or value for indicated regulation

Water-quality 

characteristic

pH 

Dissolved solids

Chloride

Fluoride

Nitrate (as N)

Sulfate

Aluminum

Arsenic

Barium

Beryllium

Cadmium

Chromium

Copper6

Iron

Lead7

Manganese

Nickel

Selenium

Silver

Zinc

National Primary 

Drinking-Water 

Regulation3 

(MCL)

--

-

4.0

10

500

-

.05

2.0

.004

.005

.1

1.3

-

.015

-

.14

.05

-

-

National Secondary , _ , _ . . . ' Montana Drinking-Water . . , . 

Regulation3 dr,nk,ng-Wa er

(SMCL) regUlat'°n

Physical property (standard units)

6.5-8.5 

Common constituents (mg/L)

500

250

2.0 4.0

10

250

Trace elements ( mg/L)

.05-.2

.018

1.0

.04

.005

1

1.0 1.0

.3 .3

.015

.05 .05

1

.05

1

5.0 5.0

Equivalent 

trace-element 

concentration5 

for MCL or SMCL

(ug/L)

-

-

-

-

--

50-200

50

2,000

4

5

100

1,300; 1,000

300

15

50

140

50

100

5,000

'Regulations in effect as of October 1996.

2Listed only for properties, common constituents, trace elements, and radionuclides analyzed in this report.

3U.S. Environmental Protection Agency, 1996.

4Montana Department of Environmental Quality, 1995.

The U.S. Geological Survey reports trace-element concentrations in micrograms per liter.

Copper is covered under primary regulations by an "action level." 

7Lead is covered under primary regulations by an "action level."

114 Hydrogeology and aquifer sensitivity of the Bitterroot Valley, Ravalli County, Montana