Construction, Completion, and Testing of 

Replacement Monitoring Wells MW 3–2, 

MW 6–2, MW 7–2, and MW 11–2, Mountain 

Home Air Force Base, Idaho, February 

Through April 2000

Open-File Report 00–515 

U.S. Department of the Interior

U.S. Geological Survey

DEPARTMENT

OF THE

AIR FORCE
Con

Construction, Completion, and Testing of 

Replacement Monitoring Wells MW 3–2, 

MW 6–2, MW 7–2, and MW 11–2, Mountain 

Home Air Force Base, Idaho, February 

Through April 2000

By D.J. Parliman

Open-File Report 00–515

Prepared in cooperation with

Department of the Air Force

Boise, Idaho

2001
U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

Any use of firm, trade, and brand names in this report is for

identification purposes only and does not constitute 

endorsement by the U.S. Government.

Additional information can be obtained from: Copies of this report can be purchased from

District Chief U.S. Geological Survey

U.S. Geological Survey Information Services

230 Collins Road Box 25286

Boise, ID 83702-4520 Federal Center

http://idaho.usgs.gov Denver, CO 80225

e-mail: infoservices@usgs.gov
CONTENTS

Abstract .............................................................................................................................................................................

Introduction .......................................................................................................................................................................

Location and construction of monitoring wells.................................................................................................................

Borehole cuttings, well completion, and onsite water analyses........................................................................................

Post-construction testing ...................................................................................................................................................

Selected references............................................................................................................................................................

Appendix A. Well-drillers’ reports and natural gamma, spontaneous potential, resistivity, caliper, and temperature 

logs for MW 3–2, MW 6–2, MW 7–2, and MW 11–2, Mountain Home Air Force Base, Idaho..............................

FIGURES

1. Map showing locations of selected wells on and near the Mountain Home Air Force Base, Idaho .......................

2. Hydrographs of water levels in wells 4S-5E-25BBC1 and MW 3, January 1967 to April 2000, at and near

Mountain Home Air Force Base, Idaho ..................................................................................................................

3. Diagram showing generalized monitoring well construction and description of lithology, Mountain Home 

Air Force Base, Idaho..............................................................................................................................................

TABLE

1. Selected location, construction, onsite water analyses, and post-construction test data for monitoring wells 

MW 3–2, MW 6–2, MW 7–2, and MW 11–2, Mountain Home Air Force Base, Idaho ........................................

CONVERSION FACTORS AND OTHER ABBREVIATED UNITS

Multiply By To obtain

acre 4,047 square meter

foot (ft) 0.3048 meter

cubic foot per minute (ft3/min) 0.02832 cubic meter per minute

gallon per minute (gal/min) 0.06309 liter per second

horsepower (hp) 746 watt

inch (in.) 25.4 millimeter

mile (mi) 1.609 kilometer

pound per square inch (lb/in2) 6.895 kilopascal

square mile (mi2) 2.590 square kilometer

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

°F=(1.8) (°C)+32

Sea level: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)—a geo

datum derived from a general adjustment of the first-order level nets of both the United States and Canada and former

“Sea Level Datum of 1929.”

iii
WELL-NUMBERING SYSTEM

The well-numbering system used by the U

logical Survey in Idaho indicates the location o

within the official rectangular subdivisions of th

lic lands, with reference to the Boise base line a

Meridian. The first segment of a well number in

cates the township, the second the range, and th

the section in which the well is situated. The let

lowing the section number indicate the well loc

within the section: The first letter denotes the 1

tract; the second, the 40-acre tract; and the third

10-acre tract. The letters are assigned in a coun

clockwise direction, beginning in the northeast 

ter. The last numeral is a serial number assigne

the well is inventoried. Thus, well 4S-5E-25BB

the SW 1/4 NW 1/4 NW 1/4 sec. 25, T. 4 S., R. 5 

was the first well inventoried in that tract.

T.1S.

11 10 9 8 7 6 5 4 3 2

9 10 11

8 7 6 5 4 3 2 R.1E.

4S-5E-25BBC1

Section 25

25

A

B

A

D

D

B

C

D

C

C

D

C

A

B

A

B

D

C

D

C

A

B

A

B

T. 4 S.

R. 5 E.

1 2

4 3

5

12 11

9 10

8 7

13 14

16 15

17 18

24 23

21 22

20 19

28

26 27

29 30

36 35

33 34

32 31

6

iv
1

Abstract

In February and March 2000, the U.S. Geological Survey Western Regional Research Drilling Operation constructed replacement monitoring wells MW 3–2, MW 6–2, MW 7–2, and MW 

11–2 as part of a regional ground-water monitoring network for the Mountain Home Air Force 

Base, Elmore County, Idaho. Total well depths 

ranged from 435.5 to 456.5 feet, and initial depthto-water measurements ranged from about 350 to 

375 feet below land surface. After completion, 

wells were pumped and onsite measurements 

were made of water temperature, specific conductance, pH, and dissolved oxygen. At each well, 

natural gamma, spontaneous potential, resistivity, 

caliper, and temperature logs were obtained from 

instruments placed in open boreholes. A threedimensional borehole flow analysis was completed for MW 3–2 and MW 11–2, and a video 

log was obtained for MW 11–2 to annotate lithology and note wet zones in the borehole above saturated rock.

INTRODUCTION

Mountain Home Air Force Base (MHAFB) covers about 9 mi2 in southwestern Elmore County, Idaho 

(fig. 1). Geology of MHAFB includes varying depths 

of soil and unconsolidated sediments overlying a thick 

sequence of fractured basalt flows with interbeds of 

cinders or sediments at irregular intervals (Young, 

1977, p. 8). Depth to water in the regional groundwater system, sole source of public water suppl

MHAFB, currently is about 350 to 375 ft below 

surface, and ground-water movement generally 

southwestward (Young and others, 1992, sheet 

Seasonal change in water levels can exceed 10 

year in some wells; water levels are highest in a

February and lowest in about October.

Water levels in the regional system have b

declining for more than 30 years, and by 1999, 

Construction, Completion, and Testing of 

Replacement Monitoring Wells MW 3–2, 

MW 6–2, MW 7–2, and MW 11–2, Mountain 

Home Air Force Base, Idaho, February 

Through April 2000

By D.J. Parliman

USGS personnel and drilling at monitoring well 3–2,

February 2000.

ABSTRACT
2

Figure 1. Locations of selected wells on and near the Mountain Home Air Force Base, Idaho.

0 1 2 MILES

0 1 2 KILOMETERS

MOUNTAIN HOME

AIR FORCE BASE

43° 03' 45"

43° 02' 30"

22

27

34

21

28

33

20

29

32

23

26

35 36

25

24

T.

4

S.

ELMORE

COUNTY

MW 3,

MW 3–2

MW 6,

MW 6–2

MW 7,

MW 7–2

4S-5E-25BBC1

MW 11,

MW 11–2

Study

area

Boise

ELMORE

COUNTY

Base from U.S. Geological Survey

digital data, 1:24,000; Crater Rings

SE, 1992; Crater Rings SW, 1992; 

North American Datum (NAD) of 1983;

Universal Transverse Mercator (UTM)

projection, Zone 11

EXPLANATION

Monitoring well and

 identification

Well and identification
3

WATER LEVEL, IN FEET BELOW LAND SURFACE

335

360

385

410

435

460

485

360

365

370

375

380

2,713

2,688

2,663

2,638

2,613

1,588

2,563

2,645

2,640

2,635

2,630

2,625

Figure 2. Hydrographs of water levels in wells 4S-5E-25BBC1 and MW 3, January 1967 to April 2000, at and nea

Mountain Home Air Force Base, Idaho.

1967 1970 1975 1980 1985 1990 1995 2000

YEAR

4S-5E-25BBC1

Total well depth = 530 feet

MW 3

Total well depth = 390 feet

Dashed where

inferred
4

in several wells at MHAFB, part of a regional groundwater monitoring network at the Base, were within a 

few feet of the total well depth (fig. 2). During February and March 2000, the U.S. Geological Survey 

(USGS) Western Regional Research Drilling Operation 

constructed replacement monitoring wells MW 3–2, 

MW 6–2, MW 7–2, and MW 11–2, located less than 

about 15 ft from older wells MW 3, MW 6, MW 7, 

and MW 11. This report summarizes the construction, 

completion, and testing of the four replacement wells.

LOCATION AND CONSTRUCTION OF 

MONITORING WELLS

Locations of the four replacement wells are 

shown in figure 1, and a summary of well location and 

construction data is presented in table 1. Order of construction was approximately from areas with potentially the least mineralized water to areas with increasingly mineralized water, based on historical water 

analyses from older MW 3, MW 6, MW 7, and MW 

11 wells (J. Schleicher, Department of the Air Force, 

written commun., January 2000). An Ingersol-Rand 

TH75 drill rig, using high-pressure (350 lb/in2) and 

large-volume (900 ft3/min) compressed air, was used 

to construct boreholes for the wells. A high-pressure 

water sprayer was used to clean the drill rig before 

construction of the first well and after construction of 

each well.

From land surface to about 1 ft into the top of the 

basalt, a 14 1/

4-in. button bit was used, followed by 

installation of 8-in. steel casing and filling of the annulus with cement grout. An 8-in. air-hammer bit 

pleted construction of the borehole to total well 

A foaming agent (Chemex F–603 Foamer—a n

ardous, biodegradable anionic surfactant) was u

sparingly in wells MW 3–2, MW 6–2, and MW 

when the drill bit became stuck in the borehole 

because of poor cuttings circulation below large 

tured-rock zones. After completion of these we

pressure was used to pump water from the bore

and flush residual foam from the rock. No foam 

used in construction of MW 11–2.

BOREHOLE CUTTINGS, WELL 

COMPLETION, AND ONSITE WATER 

ANALYSES 

Samples of borehole cuttings were collecte

odically as wells were being drilled. Cuttings sa

were saved in zip-lock bags, and each bag was 

with date and approximate borehole depth infor

tion. Samples later were air dried and stored at 

MHAFB Environmental Flight storage facilitie

Four-in. and 1-in. flush-threaded polyviny

ride (PVC) pipes were installed into each boreh

water-quality and water-level monitoring, respe

tively. In general, a cap and a 5-ft section of bla

in. PVC pipe (cap and 10-ft section of 1-in. pip

installed at the bottom of each borehole, positio

about 0.5 ft above the bottom of the borehole. F

slotted pipe (40 ft for 4-in. pipe and 20 ft for 1-

pipe) was added, and blank pipe was used from 

slotted pipe to about 1.5 ft above land surface. W

levels were measured, and tremie pipe was used 

deliver washed gravel into the borehole around 

PVC pipe. Gravel was added from the bottom o

borehole to about 300 ft below land surface. A 

nite slurry was added by tremie pipe to the bore

above the gravel, followed by bentonite chips to 

approximately land surface.

A 1-hp Grunfos submersible pump was ins

in each well; the base of the pump was position

immediately above the top of the perforated int

A 1-in. flush-threaded pipe was attached to the 

for water delivery. Bronze faucet and pipe “T” 

were used at the top of the well, and no parts of 

in. casing or water-delivery system were glued. 

pletion of each well site included test pumping 

check pump operation and develop the well), pl

Cuttings samples from monitoring well 11–2, March 2000. ment of four steel posts around the well, pourin
5

pad about 4-in. thick around the 8-in. casing and protective posts, and construction of a steel well cap with 

padlock security fittings. Idaho Department of Water 

Resources (IDWR) well tags were welded to the outside of the 8-in. well casing, and well drillers’ reports 

of the location, construction, and lithology were filed 

with the Western Region office of IDWR in Boise, 

Idaho. Copies of the drillers’ reports are included in 

appendix A (back of report).

A diagram of generalized well construction and 

completion is shown in figure 3. Specific details of 

total depth, depth to top of perforated pipe, depth to 

top of pump, and initial water levels are described in 

table 1. 

On March 30, wells MW 3–2, MW 6–2, and MW 

7–2 were pumped (at an approximate rate of 7 to 8 

gal/min) until onsite measurements of water temperature, specific conductance, pH, and dissolved oxygen 

stabilized. Onsite water analyses from these three 

wells are shown in table 1. On April 5, personnel from 

Foothill Engineering Consultants, Inc. (Golden, Colorado), measured the water level and collected water 

samples from MW 11–2, and on April 28, USGS personnel measured the water level and collected water 

samples from the well. Water-level data and onsite 

water analyses from both dates are shown for this well 

in table 1.

POST-CONSTRUCTION TESTING

Before PVC casings were installed in the replacement wells, natural gamma, spontaneous potential 

(SP), resistivity (electrical), caliper, and temperature 

logs were made in each borehole. Natural gamma logs 

were used to record changes in natural gamma radiation emitted from different types of rock. The record 

of gamma radiation can be used as a method for determining stratigraphic correlation and permeability, 

which is a measure of the ease with which water 

moves through rock. Spontaneous potential and resistivity logs were used to record changes in naturally 

occurring electrical potentials at contacts between different types of saturated rock and electrical properties 

of the saturated borehole rock. Caliper logs, made with 

a 20-in. caliper tool, were used to make borehole 

diameter measurements from land surface to the bottom of the borehole. Large fluctuations in caliper measurements in boreholes at MHAFB wells generally 

occurred at interbeds of unconsolidated rock or 

ture zones in the rock. Temperature logs were u

record changes in air and water in the borehole

urated rock, temperature logs can be used to ide

flow from various ground-water zones. Logs fo

well accompany the well driller’s report in appe

A.

Flowmeter tests were performed at MW 3–

MW 11–2. A prototype borehole Acoustic Dop

Velocimeter (ADV) was used to make direct th

dimensional measurements of in situ borehole f

both wells. Methodology, data collection proce

and flowmeter results are summarized in an unp

lished report (Newhouse and Hansen, 2000), an

copy of this report was provided to Environmen

Flight personnel at MHAFB. 

A down-hole camera was used in MW 11–

create a depth-annotated video log of lithology 

note wet zones in the borehole above saturated 

small amount of water was observed flowing fr

fracture in rock at about 176 ft below land surfa

no other flowing water was observed in the bor

above saturated rock. A copy of the video log a

provided to Environmental Flight personnel at 

MHAFB. 

No attempt was made as part of this well c

struction project to identify rock types or specif

sources of natural gamma radiation from the cu

interpret rock structure, lithology, or hydraulic 

teristics from natural gamma, spontaneous pote

resistivity, caliper, or video logs; or estimate th

gradients and potential multiple ground-water f

units from temperature and ADV measurement

ples, data, flowmeter report, and video are avai

for further investigations.

USGS personnel and down-hole camera equipment

monitoring well 11–2, March 2000.
6





10 feet of 1–inch blank

pipe with end cap

Total borehole depth about

0.5 feet below end cap

Gravel pack,

bottom of borehole

to about 300 feet

below land surface

NOT TO SCALE

Land su

Grunfos 1–horsepower,

200–240 volt, stainless

submersible pump, bottom

of pump set immediately

above top of slotted pipe

40 feet schedule 80,

flush-threaded,

factory slotted pipe

 (0.010–inch slot)

5 feet of 4–inch blank

pipe with end cap

4–inch diameter

schedule 80 (0.337 gage)

flush-threaded PVC pipe

1–inch diameter

schedule 80 (0.179 gage)

flush-threaded PVC pipe,

for water discharge

1–inch diameter

schedule 40 (0.133 gage)

flush-threaded PVC pipe,

for water level monitoring

Borehole from

141/4–inch

button bit

Borehole from

8–inch

air-hammer bit

Bentonite chips or

slurry to land surface

Cement grout

4–inch concrete pa

8–inch diameter,

(0.250 gage)

steel wall casing

Figure 3. 

Air Force Base, Idaho. (PVC, polyvinyl chloride)

Diagram showing generalized monitoring well construction and description of lithology, Mountain Home

Water level

20 feet schedule 40,

factory slotted pipe

 (0.020

flush-threaded,

–inch slot) 

Soil and

unconsolidated

sediments Variable thicknesses of fractured basalt with cinder or unconsolidated sedimentary interbeds at irregular intervals

Bronze faucet

and pipe tee

PVC cap, remove to

measure water level

PVC well seal
7

Table 1. Selected location, construction, onsite water analyses, and post-construction test data for monitoring wells MW 

MW 6–2, MW 7–2, and MW 11–2, Mountain Home Air Force Base, Idaho

[Latitude and longitude by Rockwell PLGR Global Positioning System, reported in decimal degrees and NAD27, North American Datum 

altitude by level-line survey measurement to top of concrete pad at well casing and reported in feet above sea level; depth, in feet below lan

*, water level and onsite water analyses by Foothill Engineering Consultants, Inc.; °C, degrees Celsius; μS/cm, microsiemens per centime

milligrams per liter, equivalent to parts per million; X, log completed; —, not tested]

Well data MW 3–2 MW 6–2 MW 7–2 MW 11–2

Location

Township, range, and 

1/4-1/4-1/4-1/4 section

4S-5E-20ABBA2 4S-5E-29BBDC2 4S-5E29CBBC24S-5E-33AAAC2

Latitude 43.0702629 43.0531578 43.0472870 43.0397682

Longitude 115.883446 115.891045 115.894516 115.857605

Altitude (±0.5 foot) 3,005.5 2,980.7 2,981.2 2,992.0

Well construction

Start date 2/23/2000 2/8/2000 2/18/2000 3/3/2000

End date 3/10/2000 3/10/2000 3/10/2000 3/10/2000

Total borehole depth 455 436 447 457

Total well depth 454.5 435.5 446.5 456.5

Depth to top of perforated pipe 409.5 395.5 401.5 411.5

Depth to top of pump 405 390 395 400

Date of water-level 

measurement

3/30/2000 3/30/2000 3/30/2000 4/5/2000* 4/27/

Depth to water 374.62 350.07 351.73 361.30* 362

Water quality

Date of water sample 3/30/2000 3/30/2000 3/30/2000 4/5/2000* 4/28/

Water temperature (°C) 20.2 20.0 18.5 19.4* 20

Specific conductance (μS/cm at 

25°C)

167 178 538 1,040* 1,0

pH 8.20 8.35 7.97 7.64* 7.

Dissolved oxygen

(mg/L)

6.9 8.8 6.4 8.6* 8

Post-construction tests

Natural gamma, spontaneous 

potential, resistivity, caliper, 

and temperature logs

X X X X

Three-dimensional borehole 

flow analysis

X — — X

Video log — —— X
8

SELECTED REFERENCES

Lewis, R.E., and Stone, M.A.J., 1988, Geohydrologic 

data from a 4,403-foot geothermal test hole, Mountain Home Air Force Base, Elmore County, Idaho: 

U.S. Geological Survey Open-File Report 88–166, 

30 p.

Newhouse, M.W., and Hanson, R.T., 2000, Threedimensional flow measurements of ground water in 

uncased wells completed in volcanic basalts, 

Mountain Home Air Force Base, Idaho: U.S. Geological Survey, unpublished report, 18 p.

Norton, M.A., Ondrechen, W., and Baggs, J.L., 1982, 

Ground water investigation of the Mountain Home 

plateau, Idaho: Idaho Department of Water 

Resources Open-File Report, 62 p.

Ralston, D.R., and Chapman, S.L., 1968, Groun

resources of the Mountain Home area, Elm

County, Idaho: Idaho Department of Reclam

Water Information Bulletin 4, 63 p.

Young, H.W., 1977, Reconnaissance of ground-

resources in the Mountain Home plateau ar

southwest Idaho: U.S. Geological Survey W

Resources Investigations/Open-File Report 

108, 40 p.

Young, H.W., Parliman, D.J., and Jones, M.L., 

Seasonal changes in ground-water quality a

ground-water levels and directions of groun

movement in southern Elmore County, sout

ern Idaho, including Mountain Home Air F

Base, 1990–91: U.S. Geological Survey Wa

Resources Investigations Report 92–4027, 2 
9

Appendix A. Well drillers’ reports and natural gamma, spontaneous potentia

resistivity, caliper, and temperature logs for MW 3–2, MW 6–2, MW 7–2, and MW 1

Mountain Home Air Force Base, Idaho

11

CALIPER = 20-in. caliper tool

CPS = cycles per second

DEG F = degrees Fahrenheit

DEL TEMP = delta temperature (change in temperature)

FT = feet

GAM(NAT) = natural gamma

LS = land surface

LSD = land surface datum

MIN = minute

MV = millivolts

OHM-M = ohms per meter

RES(FL) = resistivity (fluid)

RES(16N) = resistivity (probes separated by 16 

RES(64N) = resistivity (probes separated by 64 

RM = remote

SP = spontaneous potential

TEMP = air/water temperature

WL = water level

ABBREVIATIONS USED IN LOGS

Example of general information page for each log.
MW 3–2

12
13

MW 3–2
MW 6–2

14
15

MW 6–2
MW 7–2

16
17

MW 7–2
MW 11–2

18
19

MW 11–2