U.S. Department of the Interior

U.S. Geological Survey

Professional Paper 1837–A

Prepared in cooperation with the U.S. Department of Energy

DOE/ID-22246

Geochemistry of Groundwater in the Eastern 

Snake River Plain Aquifer, Idaho National 

Laboratory and Vicinity, Eastern Idaho
Cover: Big Lost River, southeastern edge of the Lost River Range, and Naval Reactors 

Facility. Photograph by U.S. Geological Survey INL Project Office, December 6, 2017.
Geochemistry of Groundwater in the 

Eastern Snake River Plain Aquifer, 

Idaho National Laboratory and Vicinity, 

Eastern Idaho

By Gordon W. Rattray

DOE/ID-22246

Prepared in cooperation with the U.S. Department of Energy

Professional Paper 1837–A

U.S. Department of the Interior

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

RYAN K. ZINKE, Secretary

U.S. Geological Survey

James F. Reilly II, Director

U.S. Geological Survey, Reston, Virginia: 2018

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Suggested citation:

Rattray, G.W., 2018, Geochemistry of groundwater in the eastern Snake River Plain aquifer, Idaho National Laboratory 

and vicinity, eastern Idaho: U.S. Geological Survey Professional Paper 1837–A (DOE/ID-22246), 198 p., https://doi.

org/10.3133/pp1837A.

ISSN 2330-7102 (online)
iii

Contents

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

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

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

Previous Investigations........................................................................................................................4

Description of Study Area ............................................................................................................................5

Geography, Climate, and Land Use....................................................................................................5

Geology...................................................................................................................................................7

Mountains .....................................................................................................................................7

Eastern Snake River Plain ..........................................................................................................7

Hydrology .............................................................................................................................................12

Surface Water............................................................................................................................12

Groundwater...............................................................................................................................12

Irrigation......................................................................................................................................17

Geochemistry Data......................................................................................................................................17

Data Sources.......................................................................................................................................17

Sample Locations................................................................................................................................17

Sample Collection and Analysis.......................................................................................................20

Analytical Results ...............................................................................................................................22

Data Quality..........................................................................................................................................24

Variability.....................................................................................................................................24

Reproducibility for Pumped Groundwater Samples ...................................................24

Reproducibility for Bailed Groundwater Samples.......................................................28

Interlaboratory Comparison............................................................................................28

Bias .........................................................................................................................................28

Pumped Groundwater Samples .....................................................................................28

Bailed Groundwater Samples.........................................................................................28

Charge Balance .........................................................................................................................29

Sources of Chemical and Isotopic Constituents ....................................................................................29

Sources of Inorganic Chemical Constituents ................................................................................29

Dissolved Gases.........................................................................................................................29

Major Ions and Dissolved Metals ...........................................................................................30

Classification of Water Types ..................................................................................................30

Interpretation of Isotope Ratios .......................................................................................................32

Hydrogen and Oxygen...............................................................................................................32

Carbon .........................................................................................................................................33

Sulfur .........................................................................................................................................33

Nitrogen.......................................................................................................................................33

Helium .........................................................................................................................................37

Strontium.....................................................................................................................................39

Uranium .......................................................................................................................................39
iv

Contents—Continued

Sources of Chemical and Isotopic Constituents—Continued

Environmental Tracers .......................................................................................................................40

Tritium .........................................................................................................................................40

Terrigenic Helium.......................................................................................................................42

Tritium/Helium-3, Chlorofluorocarbons, and Sulfur Hexafluoride......................................42

Carbon-14....................................................................................................................................45

Geochemistry of Surface Water and Groundwater...............................................................................45

Chemical and Isotopic Constituents................................................................................................46

Field Parameters........................................................................................................................46

Dissolved Gases.........................................................................................................................47

Major Ions...................................................................................................................................48

Statistical and Spatial Distribution ................................................................................48

Hydrochemical Facies .....................................................................................................49

Dissolved Metals........................................................................................................................49

Isotope Ratios.............................................................................................................................50

Stable Isotope Ratios of Hydrogen and Oxygen..........................................................50

Stable Isotope Ratios of Carbon.....................................................................................52

Stable Isotope Ratios of Sulfur.......................................................................................52

Stable Isotope Ratios of Nitrogen..................................................................................53

Isotope Ratios of Helium .................................................................................................53

Stable Isotope Ratios of Strontium and Radioisotope Ratios of Uranium...............54

Environmental Tracers ..............................................................................................................54

Tritium and Terrigenic Helium.........................................................................................54

Tritium/Helium-3, Chlorofluorocarbons, and Sulfur Hexafluoride.............................55

Carbon-14...........................................................................................................................56

Distinguishing Chemical and Isotopic Characteristics for Each Water Group ........................57

Surface Water............................................................................................................................57

Tributary Valley Groundwater..................................................................................................57

Regional Groundwater..............................................................................................................57

Geothermal Water .....................................................................................................................57

Deep Groundwater....................................................................................................................58

Contaminated Groundwater.....................................................................................................58

Natural Groundwater................................................................................................................58

Temporally Variable Water Chemistry.............................................................................................59

Surface Water............................................................................................................................59

Bicarbonate and Nitrate..................................................................................................59

Stable Isotopes of Hydrogen and Oxygen ....................................................................61
v

Contents—Continued

Geochemistry of Surface Water and Groundwater—Continued 

Temporally Variable Water Chemistry—Continued

Natural Groundwater................................................................................................................61

North INL Area ..................................................................................................................63

Northeast INL Area ..........................................................................................................63

Southeast INL Area ..........................................................................................................67

Central INL Area ...............................................................................................................67

Northwest INL Area .........................................................................................................68

Southwest INL Area .........................................................................................................68

Discussion..........................................................................................................................69

Geochemical Implications for Hydrology ................................................................................................69

Sources of Recharge .........................................................................................................................69

Tributary or Regional Water.....................................................................................................69

Sources of Recharge at Specific Areas and Wells..............................................................71

North INL Area ..................................................................................................................72

Northeast INL Area ..........................................................................................................72

Southeast INL Area ..........................................................................................................76

Central INL Area ...............................................................................................................77

Northwest INL Area .........................................................................................................78

Southwest INL Area .........................................................................................................79

Comparison with Recharge Sources Simulated with a Groundwater-Flow Model........80

Paleorecharge............................................................................................................................80

Mixing of Water...................................................................................................................................87

Groundwater Flow Directions...........................................................................................................87

Summary and Conclusions.........................................................................................................................89

Acknowledgments.......................................................................................................................................90

References Cited..........................................................................................................................................90

Glossary.......................................................................................................................................................177

Appendix 1. Water-Level Measurements.............................................................................................179

Appendix 2. Equations..............................................................................................................................191

Appendix 3. Description of Water Groups............................................................................................195
vi

Figures

1. Map showing geographic features and facilities at the Idaho National Laboratory

and vicinity, eastern Idaho..........................................................................................................2

2. Map showing drainage basins adjacent to the Idaho National Laboratory where

the chemistry of groundwater was investigated with geochemical mass-balance

models, eastern Idaho .................................................................................................................6

3. Maps showing land cover and use at the Idaho National Laboratory (INL) and

vicinity, eastern Idaho..................................................................................................................8

4. Map showing surface geology at the Idaho National Laboratory (INL) and vicinity,

eastern Idaho ..............................................................................................................................10

5. Graph showing mean annual discharge of the Big Lost River and INL diversion at

the Idaho National Laboratory, eastern Idaho ......................................................................13

6. Map showing locations of wells with water-level measurements and 1989

water-table contours, Idaho National Laboratory and vicinity, eastern Idaho ................15

7. Map showing hydraulic conductivities estimated from single-well aquifer tests,

Idaho National Laboratory and vicinity, eastern Idaho........................................................16

8. Maps showing location of water-quality sample collection sites outside and 

within the Idaho National Laboratory, eastern Idaho...........................................................18

9. Map showing wells and spatially defined areas at the Idaho National Laboratory

and vicinity, eastern Idaho........................................................................................................25

10. Trilinear diagram and map showing hydrochemical facies of surface water 

and groundwater in the study area, Idaho National Laboratory and vicinity, 

eastern Idaho ..............................................................................................................................34

11. Graph showing local meteoric water lines for summer and winter precipitation,

stable isotope ratios of hydrogen and oxygen for surface-water and groundwater

samples collected from the study area, evaporation lines, and the region that

represents most 2H and 18O values in natural groundwater at the Idaho National

Laboratory, eastern Idaho.........................................................................................................36

12. Graph showing helium concentrations and the isotope ratios of helium for

groundwater samples, Idaho National Laboratory and vicinity, eastern Idaho...............38

13. Graphs showing activity of tritium in surface water and groundwater, the 

estimated monthly activity of tritium in precipitation, decay curves representing 

the possible evolution of tritium activities in pre-bomb and post-bomb recharge 

from precipitation, and areas on the graph representing old groundwater, young 

water, mixtures of young and old water, and wastewater, Idaho National 

Laboratory and vicinity, eastern Idaho....................................................................................41

14. Graph showing activity of tritium and percent terrigenic helium, ranges of tritium

activities that indicate the qualitative age of groundwater, and ranges of terrigenic

helium that were interpreted to represent specific sources of helium and water,

Idaho National Laboratory and vicinity, eastern Idaho........................................................43

15. Graph showing the stable isotope ratios of oxygen at different elevations for

surface water and groundwater from the Birch Creek, Little Lost River, and 

Big Lost River valleys, eastern Idaho ......................................................................................51
vii

16. Graph showing carbon-14 activities, tritium activities, and carbon-13/carbon-12

values in groundwater, Idaho National Laboratory and vicinity, eastern Idaho..............56

17. Time series graphs showing bicarbonate and nitrate concentrations and monthly

discharge or daily storage volume, Idaho National Laboratory and vicinity, eastern

Idaho .............................................................................................................................................60

18. Time series graphs showing monthly stable isotope ratios of oxygen (δ18O) for

surface water from the Big Lost River (BLR), Little Lost River (LLR), Birch Creek, 

and Mud Lake and the daily discharge of the BLR and LLR and storage of water 

in Mud Lake from January 1991 to July 1992, Idaho National Laboratory and 

vicinity, eastern Idaho................................................................................................................62

19. Time series graphs showing water levels and chloride and nitrate concentrations

for selected wells, Idaho National Laboratory and vicinity, eastern Idaho......................64

20. Graph showing concentrations of silica and lithium for surface water and

groundwater, Idaho National Laboratory and vicinity, eastern Idaho...............................70

21. Map showing wells within spatially defined areas and the division of tributary

water and regional groundwater based on a 5 microgram per liter (μg/L) lithium

concentration and lithium concentrations less than 8 μg/L and greater than 

10 μg/L, Idaho National Laboratory and vicinity, eastern Idaho .........................................73

22. Graphs showing strontium and uranium isotope ratios in surface water and

groundwater and binary mixing lines between various sources of recharge, 

Idaho National Laboratory and vicinity, eastern Idaho........................................................74

23. Graph showing stable isotope ratios of oxygen and carbon for selected

surface-water and groundwater sites, Idaho National Laboratory and vicinity,

eastern Idaho ..............................................................................................................................78

24. Maps showing sources of recharge and mixing of water, Idaho National 

Laboratory and vicinity, eastern Idaho....................................................................................84

25. Map showing backward particle tracking starting locations and source water

areas for particles released in model layer 1, Idaho National Laboratory and

vicinity, eastern Idaho................................................................................................................86

26. Map showing areas of recharge from tributary valley and regional groundwater,

approximate location of groundwater that is a 90:10 mixture of regional

groundwater and tributary valley groundwater, water-table contours for spring

1995, and approximate groundwater flow directions, Idaho National Laboratory 

and vicinity, eastern Idaho........................................................................................................88

27. Boxplots showing statistical distribution of chemical and isotopic constituents in 

surface water and groundwater, Idaho National Laboratory and vicinity, 

eastern Idaho ............................................................................................................................102

28. Maps showing geographic distribution of selected chemical and isotopic 

constituents in surface water and groundwater, Idaho National Laboratory 

and vicinity eastern Idaho.......................................................................................................109

Figures—Continued
viii

Tables

1. Estimated rates of recharge to the eastern Snake River Plain aquifer for 

selected water-budget components, Idaho National Laboratory and vicinity, 

eastern Idaho, 1980 ....................................................................................................................14

2. Laboratories that completed water-quality analyses...........................................................21

3. Stable isotope ratios of hydrogen and oxygen for the Big Lost River below 

Mackay Reservoir, Little Lost River near Howe, Birch Creek at Blue Dome, and 

Mud Lake near Terreton, Idaho National Laboratory and vicinity, eastern Idaho, 

1991–92 .........................................................................................................................................22

4. Concentrations of bicarbonate and nitrate for selected periods for the Big Lost

River near Arco, Little Lost River near Howe, and Mud Lake near Terreton, Idaho

National Laboratory and vicinity, eastern Idaho ...................................................................23

5. Quality-control samples collected at Idaho National Laboratory and vicinity,

eastern Idaho ..............................................................................................................................26

6. Chemical constituents with a replicate result exceeding the acceptance criteria........27

7. Potential sources of inorganic chemical constituents to the eastern Snake River

Plain aquifer, Idaho National Laboratory and vicinity, eastern Idaho................................31

8. Waste constituents disposed to the subsurface, Idaho National Laboratory, 

eastern Idaho ..............................................................................................................................32

9. Primary sources of recharge at groundwater sampling sites, Idaho National

Laboratory and vicinity, eastern Idaho....................................................................................82

10. Site name, primary source of data, and alternate and abbreviated names for

water-quality sites, Idaho National Laboratory and vicinity, eastern Idaho...................140

11. Site information, including site name, U.S. Geological Survey site number, 

location, altitude, well depth, open interval, approximate depth to water, 

depth of open intervals below water table, aquifer material, water use, and 

hydraulic conductivity, Idaho National Laboratory and vicinity, eastern Idaho ............145

12. Measurements of field parameters and helium and the calculated partial 

pressure of carbon dioxide, Idaho National Laboratory and vicinity, eastern 

Idaho ...........................................................................................................................................151

13. Concentrations of major ions, silica, and the charge balance for each waterquality analysis, Idaho National Laboratory and vicinity, eastern Idaho ........................157

14. Concentrations of selected dissolved metals, Idaho National Laboratory and

vicinity, eastern Idaho..............................................................................................................162

15. Stable isotope ratios of hydrogen, oxygen, carbon, sulfur, and nitrogen and the 

isotope ratio of helium, Idaho National Laboratory and vicinity, 

eastern Idaho ............................................................................................................................166 

16. Stable isotope ratios of strontium and radioisotope ratios of uranium, Idaho

National Laboratory and vicinity, eastern Idaho .................................................................170

17. Activity of tritium and approximate age of water samples, calculated percentage 

of terrigenic helium, apparent age of young fraction of groundwater estimated 

from environmental tracer data, and activity of carbon-14, Idaho National 

Laboratory and vicinity, eastern Idaho..................................................................................172
ix

Conversion Factors

U.S. customary units to International System of Units

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L) 

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

Radioactivity

picocurie per liter (pCi/L) 0.037 becquerel per liter (Bq/L) 

Hydraulic conductivity

foot per day (ft/d) 0.3048 meter per day (m/d)

Hydraulic gradient

foot per mile (ft/mi) 0.1894 meter per kilometer (m/km)

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

°F = (1.8 × °C) + 32.

Datums

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 

(NGVD 29).

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

Altitude or elevation, as used in this report, refers to distance above the vertical datum.

Supplemental Information

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius 

(μS/cm at 25 °C).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) 

or micrograms per liter (μg/L).

Concentrations of carbon-14 in water are given in percent modern carbon (pmC).
x

Abbreviations

ATRC Advanced Test Reactor Complex

AVH axial volcanic highland

BC Birch Creek

BLR Big Lost River

CFA Central Facilities Area

DOE U.S. Department of Energy

ESRP eastern Snake River Plain

INL Idaho National Laboratory

INEL Idaho National Engineering Laboratory

INTEC Idaho Nuclear Technology and Engineering Center

IQR Inner quartile range

ISU Idaho State University Chemistry Laboratory

LLR Little Lost River

LMWL local meteoric water line

MFC Materials and Fuels Complex

NAD North American Datum or normalized absolute difference

NGL Noble Gas Laboratory

NRF Naval Reactors Facility

NWIS U.S. Geological Survey National Water Information System

NWQL U.S. Geological Survey National Water Quality Laboratory

pmC percent modern carbon

QC quality control

RESL Radiological and Environmental Sciences Laboratory

RPD relative percent difference

RSD relative standard deviation

RWMC Radioactive Waste Management Complex

SITL U.S. Geological Survey Stable Isotope and Tritium Labs

STP standard temperature and pressure

TAN Test Area North

USGS U.S. Geological Survey
Geochemistry of Groundwater in the Eastern 

Snake River Plain Aquifer, Idaho National 

Laboratory and Vicinity, Eastern Idaho

By Gordon W. Rattray

Abstract

Nuclear research activities at the U.S. Department of 

Energy (DOE) Idaho National Laboratory (INL) in eastern 

Idaho produced radiochemical and chemical wastes that 

were discharged to the subsurface, resulting in detectable 

concentrations of some waste constituents in the eastern 

Snake River Plain (ESRP) aquifer. These waste constituents 

may pose risks to the water quality of the aquifer. In order to 

understand these risks to water quality the U.S. Geological 

Survey, in cooperation with the DOE, conducted a study of 

groundwater geochemistry to improve the understanding of 

hydrologic and chemical processes in the ESRP aquifer at and 

near the INL and to understand how these processes affect 

waste constituents in the aquifer.

Geochemistry data were used to identify sources of 

recharge, mixing of water, and directions of groundwater 

flow in the ESRP aquifer at the INL. The geochemistry data 

were analyzed from 167 sample sites at and near the INL. 

The sites included 150 groundwater, 13 surface-water, and 

4 geothermal-water sites. The data were collected between 

1952 and 2012, although most data collected at the INL were 

collected from 1989 to 1996. Water samples were analyzed 

for all or most of the following: field parameters, dissolved 

gases, major ions, dissolved metals, isotope ratios, and 

environmental tracers.

Sources of recharge identified at the INL were regional 

groundwater, groundwater from the Little Lost River (LLR) 

and Birch Creek (BC) valleys, groundwater from the Lost 

River Range, geothermal water, and surface water from the 

Big Lost River (BLR), LLR, and BC. Recharge from the 

BLR that may have occurred during the last glacial epoch, 

or paleorecharge, may be present at several wells in the 

southwestern part of the INL. Mixing of water at the INL 

primarily included mixing of surface water with groundwater 

from the tributary valleys and mixing of geothermal water 

with regional groundwater. Additionally, a zone of mixing 

between tributary valley water and regional groundwater, 

trending southwesterly, extended from near the northeastern 

boundary of the INL to the southern boundary of the INL. 

Groundwater flow directions for regional groundwater were 

southwesterly, and flow directions for tributary groundwater 

were southeasterly upon entering the ESRP, but eventually 

began to flow southwesterly in a direction parallel with 

regional groundwater.

Several discrepancies were identified from comparison 

of sources of recharge determined from geochemistry data and 

backward particle tracking with a groundwater-flow model. 

Some discrepancies observed in the particle tracking results 

included representation of recharge from BC near the north 

INL boundary, groundwater from the BC valley not extending 

far enough south, regional groundwater that extends too far 

west in the southern part of the INL, and no representation of 

recharge from geothermal water in model layer 1 or recharge 

from the BLR in the southwestern part of the INL.

Introduction

The eastern Snake River Plain (ESRP) aquifer is an 

important resource for the State of Idaho because it supplies 

water for industry, to irrigate approximately 900,000 acres 

of farmland, and is the sole source of drinking water for 

approximately 200,000 people (Idaho Department of 

Environmental Quality, 2015). Nuclear research activities at 

the Idaho National Laboratory (INL), a U.S. Department of 

Energy (DOE) site established on the ESRP in eastern Idaho in 

1949, produced liquid and solid radiochemical and chemical 

wastes that were disposed to the subsurface at various INL 

facilities (fig. 1). The disposal of these wastes resulted in 

detectable concentrations of some waste constituents in the 

ESRP aquifer (Davis and others, 2013).
2 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig01

13132520

13132513

I-15 

Birch Creek

Camas Creek

Big Lost River

Snake River

Henrys Fork

Medicine

Lodge Creek

Little Lost River Mud Lake

Beaverhead Mountains

Centennial

Mountains

Pioneer

Range

Lost River Range

Lemhi Range

Arco

Howe

Hamer

Spencer

Kilgore

Terreton

Blue Dome

Idaho Falls

Materials and

Fuels Complex

Radioactive Waste

Management Complex

Central Facilities Area

Idaho Nuclear Technology and Engineering Center

Advanced Test

Reactor Complex

Naval

Reactors

Facility

Test Area North

Atomic City

Idaho

National

Laboratory

Eastern Snake River Plain

Eastern Snake River Plain

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.Coordinate system and datum: NAD 1927 UTM Zone 12N.

0 5 10 MILES0 5 10 KILOMETERS

112°00' 112°15' 112°30' 112°45' 113°00' 113°15' 113°30'

44°

15'

44°

00'

43°

45'

43°

30'

Boise

Idaho

Falls ESRP

INL

IDAHO

Study

area

Streamgage location

and number

13132520

EXPLANATION

Figure 1. Geographic features and facilities at the Idaho National Laboratory (INL) and vicinity, eastern Idaho.
Introduction 3

The presence of radiochemical and chemical wastes 

in the ESRP aquifer may pose risks to the water quality of 

the aquifer, which is a concern of the State of Idaho, DOE, 

and the public. To understand these risks to water quality, 

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

is conducting geochemistry studies, in coordination with 

groundwater-flow and contaminant-transport modeling, 

to improve the understanding of hydrologic and chemical 

processes in the ESRP aquifer at and near the INL and 

determine how these processes affect waste constituents in 

the aquifer.

Geochemistry studies are useful for investigating various 

hydrologic and chemical processes and also can provide 

information that may be used to evaluate, improve, and 

(or) calibrate groundwater-flow and contaminant-transport 

models. For example, inorganic chemistry data are helpful 

for identifying the spatial extent of similar water types and 

the chemical reactions occurring in the aquifer, the isotope 

ratios of water are useful for identifying sources of recharge1

and mixing of water, and environmental tracers are useful 

for determining groundwater ages and velocities (Pearson 

and White, 1967; Thorstenson and others, 1979; Knobel 

and others, 1998; Busenberg and others, 2001; Rattray, 

2015). Identifying sources of recharge, mixing of water, and 

groundwater flow directions and velocities in the aquifer 

may be possible from both an integrated analysis of all of 

the geochemistry data as well as using select geochemistry 

data as groundwater tracers (Gerla, 1992; Uliana and Sharp, 

2001; Weyhenmeyer and others, 2002; Larsen and others, 

2003; Plummer and others, 2004a, 2004b). Geochemistry 

data have been used to evaluate, improve, and (or) calibrate 

groundwater-flow models of the Middle Rio Grande Basin 

(Sanford and others, 2003; Plummer, Sanford, and others, 

2004; Sanford and others, 2004), a small watershed in 

Wisconsin (Keating and Bahr, 1998), and the ESRP aquifer 

(Fisher and others, 2012) and to calibrate a groundwater-flow 

and contaminant-transport model of an alluvial aquifer system 

in Denmark (Troldborg and others, 2007).

Several geochemistry studies completed at the INL 

have used some combination of inorganic chemistry, isotope 

chemistry, environmental tracers, and the mineralogy of the 

aquifer to investigate the source and extent of water types 

(Robertson and others, 1974), the estimated ages of the young 

fraction of groundwater (Busenberg and others, 2001), and 

plausible chemical reactions occurring in the aquifer (Knobel 

and others, 1997). Several recent studies investigated the 

geochemistry of sources of recharge to the ESRP aquifer 

at the INL (Carkeet and others, 2001; Swanson and others, 

2002, 2003; Ginsbach, 2013; Rattray and Ginsbach, 2014; 

Rattray, 2015) or investigated the presence of preferential 

groundwater-flow paths at the INL (Johnson and others, 2000; 

Luo and others, 2000; Roback and others, 2001; McLing 

and Roback, 2007) from ratios of strontium-87/strontium-86 

(87Sr/86Sr), uranium-234/uranium-238 (234U/238U), or both.

This study was undertaken because the recent 

availability of the geochemical characterization of source 

waters to the INL and 87Sr/86Sr and 234U/238U ratios provided 

new, valuable geochemistry data and information for 

understanding hydrologic and chemical processes at the INL. 

Possible future geochemistry studies include geochemical 

mass-balance modeling and identifying chemical reactions in 

the ESRP aquifer at the INL. The results of this, and future, 

geochemistry studies will be used to evaluate, and possibly 

calibrate, groundwater-flow and contaminant-transport 

models at the INL (Ackerman and others, 2010; Fisher and 

others, 2012).

Purpose and Scope

This study provides a comprehensive investigation of the 

geochemistry of surface water and groundwater in the region 

encompassing the mountains north and northeast of the INL 

and the ESRP at and east of the INL (fig. 1). The objectives 

of the study were to identify sources of recharge, mixing of 

water, and groundwater flow directions in the shallow (upper 

250 feet [ft]) ESRP aquifer at the INL. The objectives of this 

study were achieved through analysis of a comprehensive suite 

of geochemistry data (inorganic, isotopic, and environmental 

tracer) and of the land use, geology, and hydrology of the 

study area.

The geochemistry data compiled for this report represent 

a large number of water samples collected from sites at 

and near the INL. This compilation is more comprehensive 

and encompasses a larger spatial area (including all 

suspected areas of source water) than previous studies that 

investigated the geochemistry of groundwater at the INL

(Olmsted, 1962; Robertson and others, 1974; Busenberg 

and others, 2001). The data were compiled from existing 

data, include water-quality data collected from 167 sample 

sites, and were from water samples collected between 1952 

and 2012. Data include measured or calculated values for 

field parameters (temperature, pH, specific conductance, and 

alkalinity); dissolved gases (dissolved oxygen [DO], carbon 

dioxide [CO2], and helium [He]); major ions (calcium [Ca], 

magnesium [Mg], sodium [Na], potassium [K], bicarbonate 

[HCO3], carbonate [CO3], chloride [Cl], sulfate [SO4], 

fluoride [F], and nitrate [NO3]); silica [SiO2]; dissolved 

metals (aluminum [Al], barium [Ba], boron [B], chromium 

[Cr], iron [Fe], lithium [Li], manganese [Mn], strontium [Sr], 

1

Definitions of sources of recharge and other selected terms used in this report are in the “Glossary”.
4 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

and uranium [U]); isotope ratios2 (hydrogen-2/hydrogen-1 

[δ2H],3 oxygen-18/oxygen-16 [δ18O], carbon-13/carbon-12 

[δ13C], sulfur-34/sulfur-32 [δ34S], nitrogen-15/nitrogen-14 

[δ15N], helium-3/helium-4 [δ3He], strontium-87/strontium-86 

[87Sr/86Sr], and uranium-234/uranium-238 [234U/238U]); and 

environmental tracers (tritium [3H], terrigenic helium [Heterr], 

chlorofluorocarbon-11 [CFC-11], chlorofluorocarbon-12 

[CFC-12], chlorofluorocarbon-113 [CFC-113], sulfur 

hexafluoride [SF6], tritium/helium-3 [3H/3He]4, and 

carbon-14 [

14C]).

Previous Investigations

Several previous geochemical studies included 

interpretations of the sources of groundwater in the ESRP 

aquifer at the INL. In a study of the physical and chemical 

character of groundwater at the INL, Olmsted (1962) noted 

that Na, K, and SiO2 concentrations in groundwater from the 

northwestern part of the INL were smaller than concentrations 

of these constituents in groundwater from the southeastern 

part of the INL. Olmsted proposed that the concentrations of 

these constituents reflect different water-rock interaction in the 

groundwater source areas; small concentrations result from 

reaction with carbonate rocks in the Little Lost River (LLR) 

and Birch Creek (BC) drainage basins northwest of the INL 

(type A groundwater) and large concentrations result from 

reaction with silicic volcanic rocks in the Beaverhead and 

Centennial Mountains north and northeast of the INL (type B 

groundwater; Olmsted, 1962, p. 37–38). Olmsted (1962, p. 39) 

also noted that a top layer of dilute groundwater (as much as 

50 ft thick) may reflect infiltration of precipitation and local 

runoff on the plain and that groundwater in the eastern part of 

the INL with larger dissolved solids and Cl and smaller HCO3

concentrations was derived from return flow of irrigation 

water from the Mud Lake area northeast of the INL (fig. 1).

Schoen (1972) and Robertson and others (1974) 

evaluated the chemical composition of groundwater at the 

INL, the chemical composition of potential recharge, and 

water-rock interaction in potential areas of source water. 

Like Olmsted (1962), they determined that groundwater in 

the northwestern part of the INL was chemically distinct 

from groundwater in the southeastern part of the INL. They 

suggested that groundwater in the northwestern part of the 

INL was recharged with Ca-Mg-HCO3 water from tributary 

valleys northwest of the INL and that groundwater in the 

southeastern part of the INL was recharged with Ca-Na-HCO3

groundwater (with relatively high F, SO4, and SiO2 contents) 

originating in mountains to the northeast. Schoen (1972) and 

Robertson and others (1974) also suggested that a narrow 

zone of mixing of the two water types extended northeast 

to southwest approximately bisecting the INL, that thermal 

water may contribute small amounts of recharge to the aquifer, 

and that irrigation water could be recognized by high water 

temperature, high dissolved-solids content, and high levels 

of fertilizer-based constituents such as NO3. Mann (1986), 

McLing and others (2002), and Rattray (2015) suggested 

that a small amount of recharge at or adjacent to the INL 

may be from geothermal water upwelling from below the 

ESRP aquifer.

In studies estimating the age of the young fraction of 

groundwater at the INL, Busenberg and others (1993, 2001) 

evaluated the sources of groundwater from concentrations 

of F, Li, dissolved gases (including calculated groundwater 

recharge temperatures and concentrations of Heterr), and 3H. 

They showed that Li concentrations in groundwater were 

smaller in the northwestern than the southeastern part of 

the INL and, similar to other geochemical methods used by 

Olmsted (1962), Schoen (1972), and Robertson and others 

(1974), were useful for identifying recharge from water 

originating in tributary valleys to the northwest and recharge 

from underflow of regional groundwater from the northeast. 

Recharge temperatures, Heterr, and 3H were used to identify 

tributary and regional water as well as areas where recharge 

from precipitation may have occurred. Concentrations of He 

and F were used by Busenberg and others (2001, p. 70–73) to 

define three groundwater types at the INL: 

1. Groundwater in the western part of the INL that 

contained small concentrations of He (near air-water 

saturation) and F and that represents recharge from 

tributary valleys northwest of the INL;

2. Groundwater in the northeastern part of the INL that 

contained large concentrations of He (more than three 

times air-water saturation) and F and that represents 

recharge of regional groundwater northeast of the INL; 

and 

3. Groundwater in the southeastern part of the INL that 

contained moderate concentrations of He (as much as 

three times air-water saturation) and large concentrations 

of F, and that represents recharge of regional 

groundwater east of the INL. 

2

Isotope ratios were measured from water (δ2H and δ18O), dissolved inorganic carbon (δ13C), sulfate (δ34S), and nitrate (δ15N).

3

The delta (δ) notation for isotope ratios, and most other equations used in this report, are described in appendix 2 (eq. 2-2).

4

Helium-3 and carbon-14 are radioactive isotopes used for dating groundwater (Clark and Fritz, 1997). CFCs, SF6, and 3H/3He were used to estimate the age 

of the young fraction of groundwater (Busenberg and others, 2001).
Description of Study Area 5

Additionally, flow velocity vectors for groundwater were 

produced by Busenberg and others (2001, fig. 25) for the 

western part of the INL from 3H/3He ages of groundwater and 

the probable locations of recharge.

Geochemical mass-balance and mixing models were 

used by McLing (1994) and Schramke and others (1996) 

to identify sources of water at the INL. McLing modeled a 

north-to-south flow path extending across the INL using the 

chemistry of surface water from BC and groundwater from 

the Atomic City well as flow-path end members. A successful 

mixing model, with limited water-rock interaction (primarily 

precipitation of calcite and cation exchange), was generated 

that included surface water from BC, regional groundwater 

(referred to as Mud Lake water), and geothermal water (Heise 

Hot Springs, about 40 miles [mi] east of the INL) as sources 

of water at the Atomic City well. Schramke and others (1996) 

created models of two north-to-south flow paths, with the 

paths originating at wells near the mouths of the LLR or BC 

drainage basins and terminating at wells in the central part 

of the INL. Their most reasonable models included some 

water-rock interaction (primarily precipitation of calcite and 

montmorillonite and dissolution of silica, plagioclase, halite, 

and kaolinite) and mixing of surface water from the Big Lost 

River (BLR) and the LLR and groundwater from the LLR and 

BC drainage basins.

The geochemistry and evolution of groundwater 

recharging the INL from the north and east were investigated 

in several studies using geochemical mass-balance models. 

Geochemical mass-balance models of the BLR (north of 

Arco), LLR, and BC drainage basins (fig. 2) were developed 

by Carkeet and others (2001) and Swanson and others 

(2002, 2003). Groundwater in all these drainage basins was 

a Ca-Mg-HCO3-type water. Results from the geochemical 

mass-balance models indicated that the chemistry of the 

groundwater was controlled primarily by carbonate reactions 

and, at some wells, silicate reactions, dissolution of gypsum/

anhydrite, and dissolution of fertilizer from nearby agriculture. 

The geochemistry of the Camas and Medicine Lodge Creek 

drainage basins, which includes the southern parts of the 

Beaverhead and Centennial Mountains and the ESRP east of 

the INL (including the Mud Lake area), was investigated by 

Ginsbach (2013), Rattray and Ginsbach (2014), and Rattray 

(2015). Non-geothermal groundwater from the mountains was 

either a Ca-HCO3 or a Ca-Mg-HCO3 type water. Groundwater 

from the ESRP was a Ca-Mg-HCO3-type water or, if from 

the Mud Lake area, was various combinations of Ca-, Mg-, 

and (or) Na-HCO3-type water and one Ca-Cl-HCO3-type 

water. Geochemical mass-balance modeling indicated that the 

chemistry of groundwater in the (1) mountains was controlled 

by carbonate and silicate reactions plus dissolution of gypsum; 

(2) ESRP east of the Mud Lake area was controlled by these 

reactions plus dissolution of halite and cation exchange; and 

(3) ESRP in the Mud Lake area was controlled by carbonate, 

silicate, and redox reactions, dissolution of evaporite minerals 

and fertilizer, and cation exchange. 

Studies by Johnson and others (2000), Luo and others 

(2000), Roback and others (2001), and McLing and Roback 

(2007) used the radioisotopes of uranium, thorium, radium, 

radon, and (or) strontium to understand water-rock interaction 

and the age, flow directions, and sources of groundwater at 

the INL. Conclusions from these studies were that dissolution 

rates of basalt were about 70–800 milligrams per liter per 

year ([mg/L]/yr), that the age of groundwater ranged from 

less than 10–100 years, that preferential flow paths extended 

south-southeast from the LLR and BC valleys, and that 

stagnant flow zones were present in the central and western 

parts of the INL.

The direction of groundwater flow in the aquifer was 

inferred in numerous reports from the direction of movement 

of wastes discharged to the aquifer (Mann and others, 1988; 

Mann and Cecil, 1990; Mann and Beasley, 1994; Sorenson 

and others, 1996; Bartholomay, 2009, 2013; Davis and others, 

2013). The movement of wastes indicated that the direction 

of groundwater flow was generally south-southeast near 

Test Area North (TAN, fig. 1) and south-southwest in the 

southwestern part of the INL.

Description of Study Area

Geography, Climate, and Land Use

The study area encompasses approximately 5,000 square 

miles (mi2) of eastern Idaho (fig. 1). The southeastern part 

of the study area includes the 890-mi2 INL and includes 

approximately 2,200 mi2 of the ESRP, which is a relatively flat 

topographic depression. The northwestern part of the study 

area includes approximately 2,800 mi2 of the rugged, north- to 

northwest-trending mountains of the Pioneer, Lost River, and 

Lemhi Ranges and the Beaverhead Mountains. The mountains 

are bisected by the BLR, LLR, and BC valleys. Altitudes 

range from a low of about 4,800 ft at the BLR sinks and Mud 

Lake to a maximum of 12,655 ft in the Lost River Range 

(figs.1 and 2).
6 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig02

Birch Creek

Big Lost River

Little Lost River

Medicine Lodge Creek

Arco

Howe

Terreton

Monteview

Atomic City

Idaho

National

Laboratory

Direction of regional groundwater flow 

in Eastern Snake River Plain aquifer

Mud

Lake

INL

Spreading

areas

BLR

Sinks

and

Playas

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°0' 112°45' 112°30'

44°

00'

43°

45'

43°

30'

Eastern Snake River Plain aquifer

Drainage basins used for geochemical models 

of groundwater

Camas Creek (Rattray and Ginsbach, 2014)

Medicine Lodge Creek (Rattray, 2015)

Birch Creek (Swanson and others, 2003)

Little Lost River (Swanson and others, 2002)

Big Lost River (Carkeet and others, 2001)

Geographic features

EXPLANATION

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

Figure 2. Drainage basins adjacent to the Idaho National Laboratory where the chemistry of groundwater was 

investigated with geochemical mass-balance models, eastern Idaho.
Description of Study Area 7

The climate is semi-arid on the ESRP and continental in 

the mountains. Mean annual temperatures and mean annual 

precipitation are 5.7 °C and 8.4 inches (in.) at the INL on the 

ESRP (period of record 1950–2014, National Oceanic and 

Atmospheric Administration, 2015) and about 0.0–2.2 °C 

and 32–36 in. (mostly as snow) in the higher areas of the 

mountains (period of record 1981–2010; Prism Climate 

Group [2015]).

Land use and cover in the mountains and valleys is forest 

or bare rock at higher elevations, shrub and grassland in the 

valleys, with extensive irrigated agriculture (as indicated by 

the distribution of cultivated crops in figure 3) in the BLR and 

LLR valleys, particularly in the lower parts of the valleys, 

and minimal irrigated agriculture in the BC valley (fig. 3). 

Land cover on the ESRP is primarily shrub, bare rock, and 

grassland, with areas of irrigated agriculture east of the INL 

and wetlands within the Mud Lake Wildlife Management 

Area and Camas National Wildlife Refuge (fig. 3B). At 

the INL, land use includes industrial facilities and waste 

disposal areas, such as wastewater infiltration or evaporation 

ponds, wastewater ditches, and waste burial sites (Davis and 

others, 2013).

Geology

The geology of the study area can be divided into 

mountainous terrain and the ESRP, which are part of the 

northern Basin and Range province and the Snake River 

Plain-Yellowstone Plateau volcanic province (Link and 

Janecke, 1999; Morgan and McIntosh, 2005), respectively. 

The western Centennial Mountains5 (fig. 1) are included 

in the geologic discussion of the mountains because much 

of the groundwater northeast of the INL originates in these 

mountains. Sediment overlies rocks of these provinces 

throughout much of the study area (Lewis and others, 2012).

Mountains

The mountains are largely composed of Paleozoic and 

Mesozoic miogeosynclinal sedimentary rocks (uplifted during 

basin and range tectonism) with some Tertiary intermediate 

and silicic volcanic rocks (the Challis Volcanic Group and 

the Heise volcanic field) and Quaternary sediments (fig. 4; 

Link and Janecke, 1999). The miogeosynclinal rocks consist 

primarily of marine limestone and dolostone, but also 

include marine and continental sandstone, shale, siltstone, 

mudstone, quartzite, chert, conglomerate, and phosphorite 

(Lewis and others, 2012). The Challis Volcanic Group is 

comprised of rhyolite, dacite, and andesite, the Heise volcanic 

field is composed of rhyolite, and the sediments are largely 

alluvial deposits of gravel, sand, and silt (Lewis and others, 

2012) composed of quartz, feldspar, calcite, clays, dolomite, 

pyroxene, and biotite (Bartholomay and others, 1989; 

Bartholomay and Knobel, 1989).

There are significant differences in the geology of the 

mountain ranges, even though the mountains are largely 

composed of Paleozoic carbonate rocks (Lewis and others, 

2012). The core of the Pioneer Range is composed of 

Paleozoic carbonate rocks, but much of these carbonate 

rocks are overlain by Tertiary volcanic rocks from the Challis 

Volcanic Group (Crosthwaite and others, 1970). The Lost 

River Range also is largely composed of Paleozoic carbonate 

rocks, but includes Paleozoic and Cenozoic sandstone, shale, 

mudstone, and chert, and Tertiary volcanic rocks from the 

Challis Volcanic Group. The Lemhi Range and the western 

part of the Beaverhead Mountains (Skipp and others, 1979; 

Abplanalp and others, 2008) have a similar geology as the 

Lost River Range, but also include Proterozoic and Paleozoic 

quartzite and Tertiary rhyolite from the Heise volcanic field. 

The central and eastern parts of the Beaverhead Mountains and 

the western Centennial Mountains have a core of Paleozoic 

carbonate rocks (almost entirely overlain by Mesozoic and 

Cenozoic sandstone, shale, mudstone, and chert), Tertiary 

rhyolite from the Heise volcanic field, and small amounts 

of Tertiary volcanic rocks from the Challis Volcanic Group 

(Kirkham, 1927; Stearns and others, 1939; Witkind, 1980).

Eastern Snake River Plain

The ESRP is a bimodal volcanic province in which 

massive eruptions of rhyolites were followed by voluminous 

eruptions of basalt. On the ESRP in the vicinity of the INL, 

these eruptions resulted in late Tertiary–early Quaternary 

rhyolites that are overlain by a thick accumulation of 

numerous subhorizontal Quaternary basalt flows (Ackerman 

and others, 2006) plus surficial and interbed sediments 

(fig. 4; Doherty and others, 1979; Anderson and Liszewski, 

1997). Interbed sediments are located in interflow zones that 

consist of the highly fractured basalt and rubble at the top of 

the underlying basalt flow, the base of the overlying basalt 

flow, and any interbed sediment between the basalt flows 

(Whitehead, 1992; Welhan, Johannesen, and others, 2002).

Rhyolite is composed primarily of glass, potassium 

feldspar, plagioclase, quartz, opaque oxides, and pyroxene 

with lesser amounts of apatite and biotite and basalt is 

composed primarily of plagioclase, olivine, pyroxene, and 

iron oxide with lesser amounts of apatite and glass (Nace 

and others, 1956; Bartholomay and others, 1989; Knobel 

and others, 1997; Morgan and McIntosh, 2005; Rattray and 

Ginsbach, 2014). Surficial and interbed sediments were 

deposited by alluvial, eolian, fluvial, and lacustrine processes. 

5

As defined by Witkind (1980).
8 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig03a

I- 15

Birch Creek

Camas Creek

Big Lost River

Snake River

Pahsimeroi River

Medicine Lodge Creek

Little Lost River

Willow Creek

Arco

Howe

Rigby

Hamer

Camas

Dubois

Spencer

Kilgore

Terreton

Monteview

Blue 

Dome

Atomic City Idaho Falls

Mackay

Idaho

National

Laboratory

0 10 20 MILES

0 10 20 KILOMETERS

113°45' 113°30' 113°15' 113°00' 112°45' 112°30' 112°15' 112°00' 111°45'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15' Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

Land cover information and map from Homer and others (2007)

A

Land cover

Grassland

Evergreen forest

Pasture, hay

Shrub

Cultivated crops

Barren land, rock

Developed areas

EXPLANATION

Figure 3. Land cover and use at the Idaho National Laboratory (INL) and vicinity, eastern Idaho. (A) Land use and cover 

throughout the study area. (B) Land use and cover, highways, canals, surface-water features, and industrial facilities at the INL 

and vicinity.
Description of Study Area 9

tac18-1192_fig03b

Birch Creek

Big Lost River

Camas Creek

Little Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue 

Dome

Atomic City

Beaverhead Mountains

Lost River Range

Lemhi Range

Camas National 

Wildlife Refuge

Mud Lake Wildlife 

Management Area

Test

Area

North

Materials and

Fuels Complex

Naval Reactors Facility

Central Facilities Area

Radioactive Waste

Management Complex

Advanced Test Reactor Complex Idaho Nuclear Engineering

and Technology Center

INL spreading

areas

BLR

sinks

Playas

LLR

sinks

BC

sinks

2

3

4

A

B

C

D

1

B

Idaho National Laboratory

Medicine Lodge Creek

0 5 10 MILES

0 5 10 KILOMETERS

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

Land cover information and map from Homer and others (2007)

Irrigated land data from Idaho Department of Water Resources (2016)

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Grassland

Evergreen forest

Shrub

Irrigated lands

Groundwater irrigation

Developed areas

Pasture, hay

Cultivated crops

Barren land, rock

Surface-water irrigation

Surface-water and 

groundwater irrigation

EXPLANATION

Land cover

Canals

Figure 3.—Continued
10 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Medicine Lodge Creek

Mud

Lake

Arco

Howe

Rigby

Hamer

Dubois

Camas

Spencer

Kilgore

Terreton

Monteview

Blue Dome

Atomic City

Beaverhead Mountains

Lost River Range

Lemhi Range

Pioneer

Range

Centennial Mountains

Birch Creek

Camas Creek

Little Lost River

Big Lost River Idaho National Laboratory

Eastern Snake River Plain

A

0 10 20 MILES0 10 20 KILOMETERS

111°45' 112°0' 112°15' 112°30' 112°45' 113°0' 113°15' 113°30' 113°45'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15' Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

Surface geology from Lewis and others (2012)

Simplified surface geology

Quaternary sedimentQuaternary and Tertiary basaltTertiary rhyoliteTertiary andesite, dacite, and rhyoliteCenozoic to Paleozoic sandstone, shalePaleozoic limestone and dolostonePaleozoic syeniteProterozoic and Paleozoic quartzite

EXPLANATION

Figure 4. Surface geology at the Idaho National Laboratory (INL) and vicinity, eastern Idaho. (

A) Surface geology throughout the study area. (

B) Surface geology, 

Big Lost Trough, Mud Lake subbasin, Axial Volcanic Highland, rift zones, and rhyolitic buttes at the INL and vicinity.
Description of Study Area 11

tac18-1192_fig04b

Birch Creek

Camas Creek

Little Lost River

Big Lost River

Mud

Lake

Beaverhead Mountains

Lost River Range

Lemhi Range

Eastern Snake River Plain

Axial Volcanic Highland

Arco Rift Zone

Howe-East Butte Rift Zone

Lava Ridge-Hell’s Half Acre Rift Zone

Circular Butte-Kettle Butte Rift Zone

Big

Southern

Butte

East

Butte

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho

National

Laboratory

Medicine Lodge Creek

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°0' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

B

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

Surface geology from Lewis and others (2012)

Simplified surface geology Structural Features

Approximate extent of volcanioc rift zones and 

axial volcanic highland

Approximate extent of Mud Lake subbasin

Approximate extent of Big Lost Trough

Alluvial and eolian sediment

Lacustrine sediment

Basalt

Rhyolite

Andesite

Limestone

Sandstone

Quartzite

EXPLANATION

Figure 4.—Continued
12 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

These sediments consist of gravel, sand, silt, and clay (Nace 

and others, 1975) and are composed primarily of quartz, 

calcite, feldspar, clays, pyroxene, dolomite, and biotite 

(Bartholomay and others, 1989; Bartholomay and Knobel, 

1989; Reed and Bartholomay, 1994). Gypsum observed 

in some lacustrine sediments (fig. 4B) may indicate that 

evaporite deposits are locally present (Blair, 2002; Geslin and 

others, 2002).

Structural features in the ESRP (fig. 4B) include (1) the 

Axial Volcanic Highland (AVH), a broad linear topographic 

highland trending southwest-to-northeast formed from the 

accumulation of lava flows from basaltic volcanoes centered 

along the AVH and uplift associated with emplacement of 

rhyolite domes (Kuntz and others, 1992); (2) volcanic rift 

zones, which are broad belts of focused volcanism that 

generally trend northwestward and are perpendicular to 

the AVH and the direction of regional ground-water flow 

(figs. 2 and 4B) (Kuntz and others, 1992); (3) vent corridors, 

which are narrow zones in and near volcanic rift zones that 

contain known or inferred volcanic vents, dikes, and fissures 

(Anderson and others, 1999); (4) caldera boundaries and 

(potentially) buried faults (Ginsbach, 2013); and (5) the Big 

Lost Trough and Mud Lake subbasins, long-lived sedimentary 

basins that encompassed Pleistocene Lake Terreton (Gianniny 

and others, 2002).

Hydrology

Surface Water

Surface water at and near the INL includes the BLR, 

LLR, BC, Camas Creek, and Mud Lake. There are also several 

man-made water conveyance, wastewater discharge, and 

flood control structures at and near the INL, such as irrigation 

canals, wastewater ponds and ditches, and the INL spreading 

areas (fig. 3B).

The streams originate in the mountains northwest (BLR), 

north (LLR, BC), and northeast (Camas Creek) of the INL and 

typically are perennial in the mountain valleys and ephemeral 

on the ESRP. Much of the flow in the BLR and LLR, and most 

of the flow in BC, arises from groundwater inflow (Mundorff, 

1962; Mundorff and others, 1963; Crosthwaite and others, 

1970). Annual discharge in the BLR (fig. 5), LLR, and Camas 

Creek varies significantly depending on the amount of annual 

precipitation in the surrounding mountains (Mundorff and 

others, 1963; Ackerman and others, 2006; U.S. Geological 

Survey, 2014), but annual discharge in BC is relatively 

uniform because most of the flow is from groundwater inflow 

(Mundorff, 1962).

Water from all these streams is diverted for irrigation, 

with large amounts of water diverted for irrigation throughout 

the BLR and LLR valleys, from BC to the ESRP north of 

the INL, and on the ESRP from Camas Creek (fig. 3). Small 

amounts of water from BC and the LLR frequently flowed 

onto, or adjacent to, the INL and terminated in sinks and 

playas in either the northern part of, or just north of, the INL 

(Mundorff and others, 1963; Kjelstrom and Berenbrock, 1996; 

Swanson and others, 2003). During wet years (that is, years 

with above average precipitation) large amounts of water from 

the BLR flowed onto the INL and occasionally reached playa 4 

(figs. 3B and 5) (Bennett, 1990). Camas Creek generally flows 

as far as Camas (fig. 3) in spring and flows into Mud Lake 

during wet years.

Beginning in 1965, water from the BLR began to be 

diverted to the INL spreading areas in the southwestern 

corner of the INL (figs. 3B and 5) (Mundorff and others, 

1963; Crosthwaite and others, 1970; Bennett, 1990; Kjelstrom 

and Berenbrock, 1996), and since 1969, no water from 

BC has reached the BC sinks or playa 4 (fig. 3) because of 

construction of diversion channels used to divert most of the 

water north of the INL for power or irrigation (although some 

water is diverted to gravel pits on the INL northeast of playa 4) 

(Kjelstrom and Berenbrock, 1996; Bennett, 1990). Some water 

from the BLR reaching the ESRP is lost to evaporation, but 

most of the water recharges the ESRP aquifer by infiltrating 

through the river channel, sinks, playas, and spreading areas 

(Bennett, 1990). Rates of infiltration are variable and depend 

on pressure head and the permeability of geologic materials in 

the unsaturated zone. However, rapid vertical and horizontal 

flow of infiltrating water may occur in localized areas, such as 

the BLR sinks and the INL spreading areas, when a significant 

amount of water is available for infiltration through permeable 

geologic materials (Nimmo and others, 2002).

Sources of water at Mud Lake are streamflow from 

Camas Creek, groundwater inflow, and pumped groundwater. 

Discharge from Mud Lake occurs as evapotranspiration, 

water transported through canals to irrigate land on the 

ESRP northeast of the INL, and seepage through the lakebed 

(Spinazola, 1994).

Wastewater ponds are present at the Advanced Test 

Reactor Complex (ATRC), Idaho Nuclear Technology and 

Engineering Center (INTEC), Materials and Fuels Complex 

(MFC), and TAN and wastewater ditches are present at the 

MFC and the Naval Reactors Facility (NRF) (Davis and 

others, 2013). Most wastewater in the ditches and evaporation 

or infiltration ponds at the INL originates as groundwater 

pumped from the ESRP aquifer (precipitation runoff also may 

provide some water to ditches and ponds), and discharge from 

the ponds is from evaporation or downward infiltration.

Groundwater

Aquifers in the study area include alluvial aquifers 

in the BLR, LLR, and BC valleys and the basalt aquifer 

underlying the ESRP. The alluvial aquifers are homogeneous 

and unconfined and are recharged by groundwater inflow 

from adjacent mountains and infiltration of precipitation, 

streamflow, and irrigation water. Discharge from the alluvial 

aquifers is through consumptive use for domestic and 

agricultural use and groundwater outflow to the ESRP aquifer.
Description of Study Area 13

tac18-1192_fig05

0

100

200

300

400

196519661967196819691970197119721973197419751976197719781979198019811982198319841985198619871988198919901991199219931994199519961997199819992000200120022003200420052006200720082009201020112012

Mean annual discharge, in cubic feet per second

Water year

Big Lost River below INL diversion near Arco (13132520)

INL diversion at head near Arco (13132513)

EXPLANATION

Figure 5. Mean annual discharge of the Big Lost River and INL diversion at the Idaho National Laboratory, eastern Idaho. 

Streamgage locations are shown in figure 1.

The ESRP aquifer at and near the INL is a heterogeneous, 

unconfined, fractured-basalt aquifer. The aquifer thickness 

ranges from several hundred to several thousand feet, 

the thickness of the unsaturated zone ranges from about 

200 to 1,000 ft, and the thickness of both the aquifer and 

unsaturated zone generally increase in a north-to-south 

direction (Whitehead, 1992; Ackerman and others, 2006; 

Bartholomay and others, 2017). The aquifer includes 

hundreds of interfingered layers of basalt and sediment, with 

the thickness of individual basalt flows estimated to range 

from 2 to 100 ft (Anderson and Liszewski, 1997). Most 

groundwater flow in the aquifer is horizontal and occurs in 

the rubble- and sediment-filled interflow zones between basalt 

flows (Whitehead, 1992), although dikes associated with 

volcanic rift zones and vent corridors may impede horizontal 

flow (Anderson and others, 1999). Upward and downward 

vertical groundwater movement occurs in the aquifer (Mann, 

1986; Ackerman and others, 2006), but significant vertical 

movement is probably constrained to areas where vertical

fractures are abundant (Whitehead, 1992) or vertically 

oriented fissures and dikes associated with volcanic rift zones 

or vent corridors are present. Fissures and dikes that extend 

to significant depths may facilitate the upward movement 

of geothermal water (Anderson and others, 1999) through 

rhyolite and basalt.

Recharge to the ESRP aquifer in the vicinity of the INL 

occurs as underflow of regional groundwater from the ESRP 

aquifer northeast of the INL (Ackerman and others, 2006), 

groundwater underflow from the alluvial aquifers in the 

tributary valleys (Mundorff and others, 1963; Crosthwaite and 

others, 1970; Kjelstrom and Berenbrock, 1996), infiltration 

from the BLR, LLR, BC, precipitation, irrigation water, and 

Mud Lake (Bennett, 1990; Spinazola, 1994; Ackerman and 

others, 2006), wastewater discharge (Davis and others, 2013), 

and upward flow of geothermal water across the base of the 

aquifer (Mann, 1986; McLing and others, 2002; Rattray, 

2015). A small amount of recharge may occur as groundwater 

underflow from the mountain fronts of the Lost River Range, 

Lemhi Range, and Beaverhead Mountains (Ackerman and 

others, 2006).
14 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Estimates of 1980 recharge rates to the ESRP aquifer at 

the INL (for the area of a groundwater-flow model at and near 

the INL; Ackerman and others, 2006) indicate that regional 

underflow of groundwater contributes the most recharge 

(1,225 cubic feet per second [ft3/s]), followed by groundwater 

underflow from the BLR (367 ft3/s), LLR (226 ft3/s), and 

BC (102 ft3/s) valleys and total recharge from irrigation 

(120 ft3/s; table 1). Most recharge from irrigation occurs in 

the Mud Lake area northeast of the INL (fig. 3B). Recharge 

from infiltration of the BLR (95 ft3/s) is locally important 

because of the episodic and spatially concentrated nature of 

the recharge (Ackerman and others, 2006), with significant 

amounts of recharge at the INL spreading areas, BLR sinks, 

and BLR playas (Bennett, 1990). Recharge from infiltration 

of precipitation (80 ft3/s) is spatially diffuse and generally 

contributes only a minimal amount of recharge to the aquifer 

at any location (Ackerman and others, 2006), although 

recharge from precipitation may be locally important in small 

basins where precipitation may collect or in areas of bare 

basalt where precipitation may infiltrate rapidly (Garabedian, 

1992; Busenberg and others, 2001). Recharge from upward 

flow of geothermal water (50 ft3/s), infiltration from Mud 

Lake (15 ft3/s), and wastewater discharge (6 ft3/s) is small, but 

may be important locally due to the concentrated areas of this 

recharge (Spinazola, 1994; Anderson and others, 1999; Davis 

and others, 2013; Rattray, 2015).

Perched groundwater zones have formed beneath the 

ATRC, INTEC, and Radioactive Waste Management Complex 

(RWMC) due to localized infiltration of water from the BLR 

and wastewater infiltration ponds and low permeability 

geologic materials impeding the downward movement of 

water (Cecil and others, 1991; Bartholomay and Tucker, 

2000; Davis and others, 2013). Perched water zones persist as 

long as the source of the infiltrating water remains; when the 

source of infiltrating water is removed, the perched water zone 

dissipates (Davis and others, 2013).

Water-table contours for April 19896 for the ESRP aquifer

(fig. 6), interpolated from 481 water-level measurements 

(405 of the measurements were made in April; appendix 1, 

table 1-1) using the natural neighbor technique (Sibson, 1981), 

indicate that groundwater in the aquifer generally flows south 

and southwest across the INL and that hydraulic gradients 

are relatively flat throughout the INL and relatively steep 

along the northwestern and northeastern boundaries of the 

INL and southwest of the INL. The steep hydraulic gradient 

northeast of the INL may reflect a decrease in hydraulic 

conductivity due to deposition of fine-grained sediments 

along the boundary of the Mud Lake subbasin (Ackerman and 

others, 2006) or impermeable volcanic structures associated 

Table 1. Estimated rates of recharge to the eastern Snake 

River Plain aquifer for selected water-budget components, Idaho 

National Laboratory and vicinity, eastern Idaho, 1980.

[Estimated rates of recharge are from Ackerman and others (2006), Spinazola 

(1994), or were estimated using methods described in Ackerman and others 

(2006). ft3/s, cubic foot per second]

Water-budget 

component

Estimated rate of recharge 

(ft3

/s)

Infiltration

 Precipitation 80

 Big Lost River 95

 Mud Lake 15

 Irrigation-Mud Lake area 100

 Irrigation-Howe area 20

Groundwater underflow

 Regional, from northeast 1,225

 Big Lost River valley 367

 Little Lost River valley 226

 Birch Creek valley 102

Wastewater discharge 6

Upward flow of geothermal water 50

with volcanic rift zones (fig. 4B) or vent corridors (Kuntz 

and others, 1992; Anderson and others, 1999; Kuntz and 

others, 2002).

Temporal, local changes to the water table occur at the 

INL. In the western part of the INL the water table rises or 

declines non-uniformly due to either episodic, or a lack of, 

infiltration from the BLR in response to short-term (3–8 years) 

wet or dry climate cycles (Ackerman and others, 2006). In the 

eastern part of the INL the water table fluctuates seasonally 

(Bartholomay and Twining, 2015) in response to pumping of 

groundwater for irrigation (throughout the Mud Lake area) 

and infiltration of surface water used for irrigation (west and 

south of Mud Lake; fig. 3B) (Idaho Department of Water 

Resources, 2016).

Porosity of the fractured basalts ranged from 0.05 to 

0.27 percent, although these values were dependent on 

scale and the methods used to determine them (Ackerman 

and others, 2006). However, porosity and permeability 

generally are small in the massive interiors of basalt flows 

and large in the interflow zones (Welhan, Clemo, and Grego, 

2002; Welhan, Johannesen, and others, 2002; Ackerman 

and others, 2006). Hydraulic conductivities (K) estimated 

from single-well aquifer tests indicate that the aquifer has 

extreme heterogeneity in K, with K ranging more than 

six orders of magnitude (log K of -2.00 to 4.38 ft/d; fig. 7). 

6

Water-table contours were prepared for April 1989 because this period was close to the time when most of the chemistry data were collected, and the large 

number of water-level measurements made that month provided the best resolution of water-table contours.
Description of Study Area 15

tac18-1192_fig06

Birch Creek

Little Lost River

Medicine

Lodge Creek

Big Lost River

Arco

Howe

Terreton

Monteview

Atomic City

Idaho National Laboratory

Lost River Range

Lemhi Range

Beaverhead

Mountains

Mud

Lake

TAN

MFC

NRF

CFA

RWMC

ATRC

INTEC

4,450

4,475

4,500

4,525

4,550

4,575

4,425

4,400

4,600

4,625

4,675

4,650

4,700

4,725

4,750

4,775

4,200

4,625

4,300

4,600

? ?

?

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30'

44°

00'

43°

45'

43°

30'

43°

15'

Water level uncertain

Well with water-level measurement

Selected facilities at the Idaho National Laboratory

ATRC Advanced Test Reactor Complex

CFA Central Facilities Area

INTEC Idaho Nuclear Technology and Engineering Center

MFC Materials and Fuels Complex

NRF Naval Reactors Facility

RWMC Radioactive Waste Management Complex

TAN Test Area North

4,625

?

Water-table contour—Shows altitude of water 

table, 1989. Datum is National Geodetic 

Vertical Datum of 1929

EXPLANATION

Figure 6. Locations of wells with water-level measurements and 1989 water-table contours, Idaho National Laboratory 

and vicinity, eastern Idaho.
16 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig07

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

3.36

0.08

3.30 2.83

2.78

2.98

2.52

2.80

2.94

2.40

1.11

2.26

3.23 2.76

0.81 1.20 0.58

3.00 2.45

3.81

2.08

3.15

1.20

4.38

2.30

3.64

3.53

3.26

0.65

3.08

2.78

2.00

3.32

2.84

1.38

0.66

3.26

2.23

1.83

2.57

2.36

1.76

3.30

2.38

3.28

0.20

0.43 1.04 1.08 2.88

3.75

2.54

3.83

-0.58

-1.03

>3.36

-0.30

>4.04

>3.00

-0.49

<-0.77

2.92

0.25

0.90 3.53

2.18

3.61

0.99 -0.06

-0.72

-0.77 -2.00

3.30

>0.52

<-1.5

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

3.08

Hydraulic conductivity, log K in 

feet per day

2.00 to 3.00

1.00 to 2.00

>3.00

0.00 to 1.00

<0.00

EXPLANATION

Deep groundwater or geothermal water

Surface-water site

Groundwater site

Figure 7. Hydraulic conductivities estimated from single-well aquifer tests, Idaho National Laboratory and vicinity, eastern 

Idaho.
Geochemistry Data 17

Most hydraulic conductivities exceed log K values of 2 ft/d 

(Anderson and others, 1999), and most of the log K values 

of less than 1 ft/d were measured from wells in the central 

and southwestern parts of the INL. Average linear flow 

velocities of about 2–20 ft/d (Ackerman and others, 2006) 

were estimated from model ages of environmental tracers 

(Busenberg and others, 2001) and assumed first-arrival times 

of contaminants in groundwater (Barraclough and others, 

1981; Pittman and others, 1988; Mann and Beasley, 1994; 

Cecil and others, 2000).

Irrigation

Extensive irrigation adjacent to the INL occurs in 

the Howe area of the LLR valley and the Mud Lake area 

(fig. 3). Surface water from the LLR and groundwater are 

used for irrigation in the Howe area, groundwater is used 

for irrigation in areas north of Mud Lake, groundwater and 

surface water are used for irrigation in areas west of Mud 

Lake, and either surface water or groundwater is the primary 

source of irrigation water in areas south of Mud Lake (Idaho 

Department of Water Resources, 2016).

Geochemistry Data

Data Sources

The geochemistry data in this report are primarily 

from previously published data, but also include some data 

from the U.S. Geological Survey (USGS) National Water 

Information System (NWIS) database (accessible at http://

maps.waterdata.usgs.gov/mapper/) (table 10 [at back of 

report]). A few dissolved oxygen data are from written notes 

in USGS INL Project Office field notebooks. For most water 

samples data from several sources were required to provide a 

comprehensive suite of geochemistry data.

Data for 83 of the 167 sample sites were primarily from 

Busenberg and others (2000), and data for 21 of the sites were 

primarily from Rattray (2015). Data for most of the other 

sample sites were from Knobel and others (1992, 1999a, 

1999b), Carkeet and others (2001), Swanson and others (2002, 

2003), Mann (1986), Robertson and others (1974), and the 

U.S. Geological Survey (2014). Data for three sites equipped 

with multi-level-monitoring systems (wells Middle 2051, 

USGS 134, and USGS 135) were from Bartholomay and 

Twining (2010) and Bartholomay and others (2015).

Chlorofluorocarbon, sulfur hexafluoride, tritium/

helium-3, and most tritium and carbon-14 data were from 

Busenberg and others (1998, 2000, 2001). Other sources of 

tritium data were Rattray (2015), Knobel and others (1992, 

1999a, 1999b), Carkeet and others (2001), Swanson and 

others (2002, 2003), Bartholomay and Twining (2010), 

and Bartholomay and others (2015), and some carbon-14 

data were from and Mann (1986) and Schramke and others 

(1996). Uranium isotopic data were from Johnson and others 

(2000), and strontium isotopic data were from Roback and 

others (2001) and McLing and others (2002). Some of the 

hydrogen and oxygen stable isotope data were from Ott and 

others (1994), the sulfur and nitrogen stable isotope data were 

from Knobel and others (1999a), Wood and Low (1988), and 

Bartholomay and others (1994, 1995), and some dissolved 

metal data were from Liszewski and Mann (1993).

Sample Locations

Of the 167 sample sites, 154 are groundwater sites and 13 

are surface-water sites (fig. 8). Groundwater sites (table 11 [at 

back of report]) include 129 wells and 2 sites from a deep test 

hole (INEL-1) in the basalt ESRP aquifer, 19 wells in alluvium 

aquifers in tributary valleys (9 from the BLR valley, 5 from 

the LLR valley, and 4 from the BC valley) or mountain fronts 

(Reno Ranch), and 4 springs in the Beaverhead Mountains 

(Blue Spring, Heart Spring, Lidy Hot Springs, and Warm 

Spring)7. Surface-water sites include seven sites from the 

BLR, two sites each from the LLR and BC, and one site 

each from Camas Creek and Mud Lake. Ninety-five of the 

wells in the ESRP aquifer are inside the INL and include 76 

monitoring, 13 production, 5 disposal, and 1 domestic well 

(table 11). Thirty-four of the wells in the ESRP aquifer are 

outside of the INL and include 15 domestic, 11 irrigation, 

4 monitoring, and 2 each production and stock wells.

Well construction information for the 129 wells (table 11) 

in the ESRP basalt aquifer indicate that most of the wells 

have large open intervals. Consequently, withdrawal of 

groundwater by pumping may collect and mix water from 

different aquifer depths. For the three wells equipped with 

multi-level monitoring systems (instrumented with WestbayTM

packer sampling systems), water samples were collected from 

several discrete well intervals of varying depths. However, 

only samples collected from the shallowest zone in each 

multi-level monitoring well (Bartholomay and Twining, 2010; 

Bartholomay and others, 2015), which represents the shallow 

part of the ESRP aquifer, were included in this report. Based 

on the well construction information, 119 of the wells tap 

water exclusively or nearly exclusively from the shallow part 

of the ESRP aquifer and 9 wells pump water from deeper 

depths (that is, more than 250 ft below the water table). The 

depth that water was pumped from well ML 34 is unknown.

7

The lowest-altitude sites in each of the tributary valleys are on the ESRP, and the two lowest-altitude sites for the BC valley, P&W 2 and USGS 126b, also 

are within the INL boundary (fig. 8B). Water-quality samples collected from two cold springs (ML 55/Blue Spring and ML 59/Heart Spring; fig. 8A) in the 

Beaverhead Mountains are discussed with the tributary valley samples because the chemistry of these spring waters is representative of groundwater in the 

mountains that provide recharge to the tributary valleys.
18 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig08a

8

14

11

ML

CC

125

124

MSR Oar

Owen

ML 9

ML 6

ML 5

ML 2

Mays

Hwy2

Hill

ML 59

ML 58

ML 57

ML 55

ML 34

ML 33

ML 31

ML 30

ML 29

ML 28

ML 27

ML 25

ML 24

ML 23

ML 22

ML 19

ML 18

ML 17

ML 15

ML 13

ML 12

LLR H

LLR C

BC BD

BLR A

BLR M

Fulton

Coates

BC KGS

BLR MD

Wheeler

W

Muffett

Lambert

Harrell

Sorenson

SE of AC

Pancheri

McKinney

Nicholson

RF

RR

AC

LR1

WR

ACW4

KBF

KGS

WGS

ML 26

Big Lost River below Mackay Reservoir

Mud Lake Little Lost River

Big Lost River

Birch Creek

Medicine Lodge Creek

Hamer

Terreton

Blue Dome

Spencer

Dubois

Camas

Atomic City

Arco

Howe

Monteview

Idaho National Laboratory

A

Beaverhead Mountains

Pioneer

Range

Lost River Range

Lemhi Range

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

0 10 20 MILES

0 10 20 KILOMETERS

113°45' 113°30' 113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

EXPLANATION

Surface-water site and 

abbreviated name

Local well identifier—Number 

only indicates USGS well, other 

names are local well names

Spring

Thermal spring

BLR

14

Figure 8. Location of water-quality sample collection sites (A) outside and (B) within the Idaho National Laboratory, eastern Idaho. 

Site names and abbreviated names are shown in table 10.
Geochemistry Data 19

tac18-1192_fig08b

Lost River Range

Lemhi Range

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

9

7

6

5

2

1

99

98

97

90

89

88

87

86

85

83

82

65

57 36

32

31

29

27

26

24

23

22

20

19

18

17

15

12

3A

T3

T1

N9

N8

N6 N7 N2

120

117

116

115

109 108

107

105

104

103

102

101

100

M7S

N13

FS2

BFW

126b

110A

P&W2

IET1

EBR1

CFA2 CFA1

ANP9

ANP8

ANP6

Site9

Site4

INEL1

BLR AC

Site19

Site17

Site14

Area II

BLR blw LLBB

BLR INL

NPR Test

PSTF Test

NN1

AT1

TD,T2

N12N11 N10

113 112

M3S

RP

119

INEL-1 10300 & 2000 ft

134

135

M2051

Hwy3

BLR LLBB

INL Diversion at Head

Big Lost River

Birch Creek

Little Lost River

Howe

Terreton

Monteview

Idaho National Laboratory

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30'

44°

00'

43°

45'

43°

30'

B

EXPLANATION

Surface-water site and 

abbreviated name

Local well identifier—Number 

only indicates USGS well, other 

names are local well names

BLR INL

1

Figure 8.—Continued
20 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

The chemistry of water samples collected from well ML 

34 and the four shallowest deep wells (ML 15, ML 22, No 

Name 1, and Site 19, with maximum well open interval depths 

ranging from about 290 to 371 ft below the water table), was 

similar and spatially consistent with the chemistry of samples 

collected from nearby wells penetrating only the shallow 

aquifer. Consequently, 124 of the 129 water samples from 

wells in the ESRP aquifer seem to be representative of the 

chemistry of the active, shallower part of the aquifer. The 

chemistry of water samples from the five deepest wells (wells 

EBR 1, Site 9, Site 14, USGS 7, and USGS 158), which have 

maximum well open interval depths ranging from 284 to 

626 ft below the water table, is probably representative of 

groundwater from the deeper part of aquifer. Two geothermal 

water samples were collected from test hole INEL-1 at depth 

intervals of 1,511–2,206 and 4,210–10,333 ft below the 

water table.

Sample Collection and Analysis

Surface-water and spring samples were collected as grab 

samples, except for the sample collected at BLR below INL 

Diversion (June 2, 1995), which was collected using equal 

width increments. Three groundwater samples were collected 

with bailers from wells equipped with multi-level monitoring 

systems (wells Middle 2051, USGS 134, and USGS 135), 

and all other groundwater samples were collected at wells 

with either dedicated or portable pumps. Sample collection 

followed procedures and guidelines documented in the USGS 

National Field Manual for the Collection of Water-Quality 

Data (U.S. Geological Survey, variously dated) and USGS 

INL Project Office Quality Assurance Plans that were in 

place at the time of collection (Mann, 1996; Knobel and 

others, 2008). Additional sample collection information, as 

well as analytical method information, are presented in the 

reports from which the geochemistry data set was compiled 

(Robertson and others, 1974; Knobel and others, 1992, 1999a, 

1999b; Busenberg and others, 1993, 1998, 2000; Liszewski 

and Mann, 1993; Ott and others, 1994; Schramke and others, 

1996; Johnson and others, 2000; Carkeet and others, 2001; 

Roback and others, 2001; McLing and others, 2002; Swanson 

and others, 2002, 2003; Bartholomay and Twining, 2010; 

Ginsbach, 2013; Rattray and Ginsbach, 2014; Bartholomay 

and others, 2015; Rattray, 2015). 

Water samples were collected from 160 of the 167 sample 

sites between 1989 and 2012 (table 12 [at back of report]). 

Samples collected at the seven other sites included two 

groundwater samples collected in 1952 (from wells Highway 2 

and USGS 3A), two surface-water samples collected between 

1965 and 1981 (BLR near Atomic City9 and BLR near Arco), 

two geothermal samples collected in 1979 from INEL-1, and 

one groundwater sample collected in 1984 from the Highway 

3 well. Data from these seven samples were included with the 

more recent data to aid geochemical interpretation.

The 101 (nongeothermal) groundwater samples collected 

at or downgradient of the INL were collected between 1952 

and 2010 (table 12 and fig. 8). One sample was collected 

in 1952 (USGS 3A), 1 sample was collected in 1984 

(Highway 3), 12 samples were collected in 1989, 4 samples 

were collected in 1991, 79 samples were collected during 

1995 and 1996, 1 sample was collected in 2000 (USGS 126b), 

2 samples were collected in 2008 (Middle 2051, USGS 134), 

and 1 sample was collected in 2010 (USGS 135).

Samples were analyzed for all or most10 of the 

following: field parameters, dissolved gases11, major ions, 

dissolved metals, isotope ratios, and environmental tracers. 

The concentrations of CO3 and the partial pressures of 

CO2 were determined from speciation calculations with 

PHREEQC (Parkhurst and Appelo, 2013), the δ3He values 

and concentrations of Heterr were calculated from helium 

concentrations, and the model ages for the young fraction 

of groundwater were estimated from concentrations and 

(or) ratios of CFCs, SF6, and 3H/3He (Busenberg and others, 

2000, 2001).

Bicarbonate concentrations were calculated from field 

alkalinity measurements using the equation (appendix 2, 

eq. 2-1) in Hem (1992). This calculation provides a good 

estimate of bicarbonate because alkalinity in the ESRP aquifer 

is primarily from carbonate alkalinity. Only bicarbonate 

concentrations were reported in Busenberg and others (2000), 

however, and the original alkalinity measurements were not 

archived in NWIS; therefore, alkalinity (as CaCO3) from these 

samples was back calculated from the reported bicarbonate 

concentrations.

Historical data were used for time series analyses of 

bicarbonate, chloride, and nitrate concentrations and the stable 

isotope ratios of hydrogen and oxygen. The stable isotope 

ratios were from water samples collected during 1991–92 

from the BLR below Mackay Reservoir, LLR near Howe, 

8

Well USGS 15 was drilled to a depth of 1,497 ft below land surface in 1951. The well caved to 610 ft below land surface (approximately 214 ft below the 

water table) sometime between 1952 and 1960. The chemistry of water pumped from this well is not representative of groundwater from the shallow aquifer. 

Consequently, some water pumped from this well probably originates from depths greater than 610 ft below land surface.

9

Some samples are composite samples. For example, the data for BLR near Atomic City includes field parameters and some major ions measured from a 

sample collected in 1965, a chloride measurement from a sample collected in 1985, and other major ions, trace metals, and isotopes measured from samples 

collected in 1997.

10Only measurements of the stable isotope ratios of hydrogen and oxygen were included in this report for the site BLR below Mackay Reservoir.

11Dissolved-oxygen values were not measured during collection of many samples used in this report. In these cases, the DO values reported in table 12 for 

a particular site were the mean of all measurements of DO in the USGS NWIS database (U.S. Geological Survey, 2014) for that site through 2015. The ESRP 

aquifer generally was well oxygenated, with a relatively stable DO content, so these estimated values should adequately represent the DO at a particular site.
Geochemistry Data 21

BC at Blue Dome, and Mud Lake near Terreton (Ott and 

others, 1994). Bicarbonate and nitrate concentrations were 

measured in surface water samples collected from the BLR 

near Arco, LLR near Howe, and Mud Lake near Terreton 

between 1965 and 1981 and were retrieved from NWIS. 

Chloride and nitrate concentrations measured in groundwater 

samples from 17 and 7 wells, respectively, were also retrieved 

from NWIS.

Various laboratories were used for analysis of specific 

chemical constituents, although most analyses of major 

ions, dissolved metals, stable isotopes, and environmental 

tracers were completed by the USGS National Water Quality 

Laboratory (NWQL) or other USGS laboratories (table 2). 

Analyses of 14C were completed at the University of Arizona 

and the Rafter Radiocarbon Laboratory at the Institute of 

Geological and Nuclear Sciences in New Zealand, analyses of 

87Sr/86Sr and 234U/238U were completed at the USGS Metal and 

Metaloid Laboratory and Los Alamos National Laboratory, 

and analyses of helium isotopes were completed at the 

USGS Chlorofluorocarbon Laboratory and the Noble Gas 

Laboratory (NGL) at the Lamont-Doherty Earth Observatory.

Several laboratories, with differing analytical methods 

and analytical uncertainties, were used for the measurement 

of tritium activity. The NWQL and DOE Radiological and 

Environmental Sciences Laboratory (RESL) used liquid 

scintillation counting to measure tritium activities. Analytical 

uncertainties (1σ) typically were about ±13 pCi/L for NWQL 

and generally ranged from ±150 to ±200 pCi/L for RESL 

(Knobel and others, 1992, 1999a, 1999b; Carkeet and others, 

2001; Swanson and others, 2002, 2003). Low-level tritium 

activity was measured using electrolytic enrichment liquid 

scintillation counting by the NWQL and the USGS Stable 

Isotope and Tritium Labs (SITL) and 3He in-growth mass 

spectrometry by the NGL. Analytical uncertainties (1σ) 

were approximately 1.0 pCi/L for analyses by NWQL and 

NGL (Busenberg and others, 2000) and ranged from 1.9 to 

2.5 pCi/L for analyses by SITL (Ginsbach, 2013; Rattray and 

Ginsbach, 2014).

Table 2. Laboratories that completed water-quality analyses.

[Laboratory: CFC, U.S. Geological Survey (USGS) Chlorofluorocarbon Laboratory, Reston, Virginia; CUL, USGS Common-Use Laboratory, Reston, 

Virginia; ISU, Idaho State University Chemistry Laboratory; LANL, Los Alamos National Laboratory, Los Alamos, New Mexico; NGL, Noble Gas Laboratory, 

Lamont-Doherty Geological Observatory, Palisades, New York; MMIL, USGS Metal and Metalloid Isotope Laboratory, Menlo Park, California; NGL, Noble 

Gas Laboratory, Lamont-Doherty Earth Observatory, Columbia University, New York, New York; NWQL, USGS National Water Quality Laboratory, Denver, 

Colorado; RESL, Department of Energy Radiological and Environmental Sciences Laboratory; RRL, Rafter Radiocarbon Laboratory, Institute of Geological and 

Nuclear Sciences, New Zealand; SIL, USGS Stable Isotope Laboratory, Reston, Virginia; SITL, USGS Stable Isotope and Tritium Labs, Menlo Park, California; 

UA, University of Arizona, Tuscon, Arizona. Abbreviations: CFC, chlorofluorocarbon; He, helium; 3He, helium-3; SF6, sulfur hexafluoride; –, not applicable]

Data source

Chemical constituent analyzed at laboratory

Major ions, 

metals, nitrate

Stable 

isotopes Tritium He, 3

He, 

CFCs, SF6

Carbon-14 Strontium and 

uranium isotopes

Bartholomay and Twining, 2010 NWQL NWQL NWQL, RESL – – –

Bartholomay and others, 2015 NWQL NWQL NWQL, RESL – – –

Busenberg and others, 1993 – – – CFC – –

Busenberg and others, 1998 – – – CFC – –

Busenberg and others, 2000 CUL SIL, CFC, NGL NWQL, NGL CFC, NGL RRL –

Carkeet and others, 2001 NWQL, ISU NWQL NWQL – – –

Ginsbach, 2013 NWQL SIL SITL CFC – –

Johnson and others, 2000 – – – – – MMIL

Knobel and others, 1992 NWQL – NWQL, RESL – – –

Knobel and others, 1999a NWQL NWQL NWQL – – –

Knobel and others, 1999b NWQL – NWQL – – –

Liszewski and Mann, 1993 NWQL – – – – –

Mann, 1986 NWQL – – – – –

McLing and others, 2002 – – – – – MMIL

Ott and others, 1994 – NWQL – – – –

Rattray, 2015 NWQL NWQL – – – –

Rattray and Ginsbach, 2014 NWQL SIL SITL CFC – –

Roback and others, 2001 LANL – – – – LANL, MMIL

Robertson and others, 1974 Unknown – – – – –

Schramke and others, 1996 – – – – UA –

Swanson and others, 2002 NWQL, ISU NWQL NWQL – – –

Swanson and others, 2003 NWQL, ISU, CUL NWQL NWQL – – –

U.S. Geological Survey, 2014 NWQL NWQL NWQL – – –
22 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Analytical Results

Analytical results for surface-water and groundwater 

samples are presented in tables 12–17 (at back of report). 

Values for field parameters and dissolved gases are shown in 

table 12, concentrations of major ions, silica, and the charge 

balance for each water sample are shown in table 13 (at back 

of report), and concentrations of selected dissolved metals 

are shown in table 14 (at back of report). Isotope ratios are 

shown in tables 15 and 16 (at back of report), and activities 

of the radioisotopes 3H and 14C, the approximate age of the 

water based on 3H activity, the percentage of Heterr, and the 

apparent age of the young fraction of groundwater are shown 

in table 17 (at back of report). The CFC, SF6, and 3H/3He data 

used to estimate the apparent age of the young fraction of 

groundwater were presented in tables in Busenberg and others 

(1998, 2000, 2001). Stable isotope ratios of hydrogen and 

oxygen and concentrations of bicarbonate and nitrate used for 

time series analysis of surface water sites are shown in tables 3

and 4, respectively.

The geochemistry data in tables 12–17 were grouped 

by water type (surface water, geothermal water) and 

geographic location (tributary valley groundwater, regional 

groundwater, groundwater at the INL)12 .Surface water, 

tributary valley groundwater, regional groundwater, and 

geothermal water are all sources of recharge to groundwater at 

the INL. Groundwater at the INL includes deep groundwater

(water depths more than 250 ft below the water table), 

groundwater probably influenced by industrial wastewater 

discharge (herein referred to as contaminated groundwater), 

and natural groundwater (shallow groundwater [water 

depths less than 250 ft below the water table]) probably 

not influenced (with respect to inorganic and radiochemical 

constituents) by industrial wastewater discharge.

12Definitions of these water groups are in the Glossary, and expanded descriptions of these water groups are in appendix 3. Tributary valley groundwater 

includes water from two cold springs, ML 55 and ML 59, in the Beaverhead Mountains because the chemistry of water from these springs is representative of 

groundwater in the mountains that provides recharge to the tributary valleys.

[Data from Ott and others (1994). Location of sites shown in figures 8–9. Abbreviations: δ2

H and δ18O, delta notations for the stable isotopes of hydrogen and 

oxygen, respectively; nd, not determined; ±, plus or minus]

Table 3. Stable isotope ratios of hydrogen and oxygen for the Big Lost River below Mackay Reservoir, Little Lost River near Howe, 

Birch Creek at Blue Dome, and Mud Lake near Terreton, Idaho National Laboratory and vicinity, eastern Idaho, 1991–92.

Date 

sampled

Big Lost River below 

Mackay Reservoir

Little Lost River 

near Howe

Birch Creek at 

Blue Dome

Mud Lake near 

Terreton

δ2

H±1.5

(permil)

δ18O±0.15 

(permil)

δ2H±1.5 

(permil)

δ18O±0.15 

(permil)

δ2H±1.5 

(permil)

δ18O±0.15

(permil)

δ2H±1.5

(permil)

δ18O±0.15

(permil)

03-28-91 -138.0 -18.00 -137.0 -18.10 -143.0 -18.70 -132.0 -17.75

05-02-91 -135.0 -17.85 -136.0 -18.10 -140.0 -18.55 -133.0 -17.60

05-31-91 -135.0 -17.75 -137.0 -18.05 -141.0 -18.60 -134.0 -17.85

07-02-91 -129.0 -17.20 -137.0 -18.00 -140.0 -18.75 -131.0 -17.75

07-30-91 -129.0 -17.05 -138.0 -18.00 -142.0 -18.65 -133.0 -17.70

08-29-91 -133.0 -17.30 -137.0 -17.80 -141.0 -18.70 -134.0 -17.85

10-02-91 -135.0 -17.80 -139.0 -18.15 -142.0 -18.70 -135.0 -17.75

11-04-91 -136.0 -18.00 -139.0 -18.25 -142.0 -18.55 -133.0 -17.30

12-06-91 nd nd -139.0 -18.10 -142.0 -18.55 -129.0 -16.70

01-03-92 -136.0 -17.85 -139.0 -18.20 -142.0 -18.75 -130.0 -16.90

02-07-92 -136.0 -17.95 -139.0 -18.20 -142.0 -18.70 -135.0 -17.50

03-06-92 -136.0 -18.00 -139.0 -18.25 -142.0 -18.75 -122.0 -15.55

04-06-92 -136.0 -17.80 -138.0 -18.00 -142.0 -18.60 -133.0 -17.60

04-30-92 -137.0 -17.75 -137.0 -17.85 -142.0 -18.70 -135.0 -17.70

06-18-92 -134.0 -17.45 -137.0 -18.10 -142.0 -18.65 -134.0 -17.80
Geochemistry Data 23

[Location of sites shown in figures 8–9. Abbreviations: mg/L, milligram per liter; N, nitrogen; nd, not determined]

Table 4. Concentrations of bicarbonate and nitrate for selected periods for the Big Lost River near Arco, Little Lost River near Howe, 

and Mud Lake near Terreton, Idaho National Laboratory and vicinity, eastern Idaho.

Big Lost River near Arco Little Lost River near Howe Mud Lake near Terreton

Date Bicarbonate 

(mg/L)

Nitrate

(mg/L as N)

Date Bicarbonate 

(mg/L)

Nitrate

(mg/L as N)

Date Bicarbonate 

(mg/L)

Nitrate

(mg/L as N)

10-01-65 209 0.16 04-02-65 203 0.23 04-01-68 139 0.29

12-01-65 247 0.54 09-28-67 194 0.18 10-14-68 144 0.18

01-10-66 227 0.38 11-15-68 191 0.18 04-02-69 145 0.29

02-15-66 230 0.38 05-30-69 130 0.18 12-24-69 159 0.59

03-28-66 219 0.29 09-17-69 196 nd 04-13-70 150 0.36

05-04-66 234 0.45 12-14-69 224 0.27 09-18-70 144 0.36

06-09-66 223 0.09 05-14-70 187 0.27 05-27-71 151 0.25

07-08-66 240 0.02 06-04-70 95 0.25 10-27-71 164 0.58

08-25-66 291 0.05 08-13-70 184 0.16 04-18-72 183 0.18

09-30-66 256 nd 05-22-71 149 0.18 09-25-72 150 1.30

11-01-66 270 0.02 02-28-72 233 4.10 05-24-73 150 0.88

12-05-66 251 0.18 07-12-72 177 0.06 10-25-73 148 0.48

01-04-67 285 0.34 09-19-72 191 0.11 05-15-74 132 0.71

02-06-67 268 0.27 07-18-73 201 0.18 09-27-74 103 0.09

03-15-67 282 0.18 09-18-73 149 7.50 07-31-75 126 0.03

04-17-67 277 0.14 05-14-74 138 0.25 09-12-75 90 0.06

05-25-67 214 0.11 09-24-74 190 0.33 10-05-76 100 0.12

06-14-67 180 0.18 07-23-75 164 0.11 06-30-77 110 nd

07-07-67 172 0.14 03-03-76 143 1.20 10-26-77 150 0.43

08-24-67 255 0.25 05-25-76 123 0.14 07-20-78 nd 0.04

09-26-67 230 0.18 07-16-76 167 0.18 08-22-78 120 0.33

12-08-67 248 0.59 10-20-76 170 0.13

02-12-68 252 0.50 08-26-77 190 0.09

03-18-68 240 0.43 05-08-78 160 nd

04-23-68 168 0.27 09-22-78 170 0.47

05-28-68 249 0.05 08-28-79 nd 0.13

08-05-68 235 0.20 12-04-79 nd 0.45

09-06-68 232 0.18 05-18-80 nd 0.24

10-11-68 257 0.41 10-30-80 nd 0.15

11-16-68 233 0.29 06-05-81 130 0.11

05-30-69 174 0.27 07-21-81 nd 0.03

08-20-69 227 0.09

05-13-70 240 0.27

06-05-70 268 0.16

08-12-70 269 0.38
24 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

The geochemistry of natural groundwater varies spatially 

in response to numerous, but chemically distinct, sources 

of recharge. Consequently, the 58 natural groundwater 

samples were grouped into spatially defined areas based 

on their similarity of potential source waters and chemical 

and isotopic compositions (tables 12–17). Spatially defined 

areas for natural groundwater were defined as the North, 

Northeast, Southeast, Central, Northwest, and Southwest INL 

Areas (fig. 9).

Data Quality

The data quality of environmental samples was evaluated 

from quality control (QC) samples collected to estimate 

the variability and contamination bias of chemical and 

radiochemical constituents in groundwater samples (no QC 

samples were collected for surface-water samples) and the 

charge balance of surface-water and groundwater samples. 

Variability and contamination bias were estimated from 

analysis of field replicates and field or equipment blanks 

(table 5), respectively. Replicate samples also were collected 

for interlaboratory comparison of analytical results from the 

NWQL and Idaho State University (ISU) laboratories.

Many laboratories were used for analysis of chemical 

and radiochemical constituents (table 2). Except for tritium 

and the samples collected in 195213 (table 12), the methods 

used by the different laboratories for analysis of specific 

chemical and radiochemical constituents had similar detection 

limits and precision. Consequently, all replicate and blank 

results for specific chemical and radiochemical constituents 

were evaluated collectively and the results were considered 

representative of groundwater samples except for analyses 

of tritium, samples collected in 1952, replicates collected 

for interlaboratory comparison, and the three groundwater 

samples collected with bailers.

Variability

A total of 10114 replicates were collected with the 

groundwater samples and were used to evaluate variability for 

every chemical constituent presented in this report except for 

87Sr/86Sr, 14C, He, δ3

He, CFCs, and SF6 (table 5). All replicates 

were collected as duplicates. Of these replicates, 64 were used 

to evaluate the variability of chemical constituents in pumped 

groundwater samples, 24 were used to evaluate the variability 

of chemical constituents in samples collected with bailers 

from wells equipped with multi-level monitoring systems, and 

13 were used for comparison of analytical results from the 

NWQL and ISU laboratories.

Multiple sample bottles were collected for 149 CFC 

samples, 6 He samples, and 5 δ3He samples (Busenberg and 

others, 1998, 2000). These samples were treated as replicates, 

generally were collected as duplicates or triplicates, but also 

included higher number replicates.

Variability for each chemical constituent, as well as 

the variability of chemical constituents analyzed by both 

the NWQL and ISU, was evaluated by calculating the 

reproducibility of chemical constituents from replicates. 

Reproducibility of chemical constituents was calculated as 

normalized absolute difference (NAD),15 relative standard 

deviation (RSD), or relative percent difference (RPD) 

(table 5; appendix 2, eqs. 2-3–2-8). Acceptable reproducibility 

(acceptance criteria) for a chemical constituent from an 

individual replicate was defined as an NAD less than or equal 

to 1.96, RSD less than 14 percent, or RPD less than 20 percent 

(Rattray, 2012, 2014; Bartholomay and others, 2015). 

Acceptable reproducibility for the collective set of replicates 

was defined as a chemical constituent having acceptable 

reproducibility in greater than or equal to 90 percent of all 

replicates from which the constituent was analyzed (Rattray, 

2012, 2014). Replicate data, statistical calculations of 

reproducibility, and (or) a discussion of quality assurance was 

presented in each of the reports listed in table 5.

Replicates were used to evaluate the reproducibility 

of 29 chemical constituents (table 5). The acceptance 

criteria for reproducibility for an individual replicate was 

exceeded for 12 constituents for pumped groundwater 

samples, 4 constituents for bailed groundwater samples, and 

1 constituent for interlaboratory comparison (table 6). 

Reproducibility for Pumped Groundwater Samples

The 12 constituents with a result that exceeded the 

acceptance criteria for reproducibility in pumped groundwater 

samples were Cl, SO4, F, Al, Cr, Fe, δ15N, 3H, δ3He, CFC-11, 

CFC-12, and CFC-113. The percentage of acceptable results 

for these 12 constituents was 93 percent for Cl and SO4, 

83 percent for 3H and CFC-12, 81 percent for Cr and CFC-11, 

75 percent for F and δ15N, 73 percent for Al, 60 percent for 

δ3He, 53 percent for Fe, and 40 percent for CFC-113 (table 6). 

Ten of these constituents did not meet the acceptance criteria 

for percentage of acceptable results for the collective set of 

replicates (≥90 percent).

13Chemical analyses (particularly for pH, alkalinity, and iron) from water samples collected in 1952 were less accurate than analyses from the 1980s through 

2010s. A discussion of the accuracy and uncertainty of these analyses is presented in Robertson and others (1974).

14Ott and others (1994) collected four replicates of groundwater samples. However, only surface-water data were used from that report, so the replicates of 

groundwater were not included in the data-quality assessment presented herein.

15NAD is referred to as the Z-value in Knobel and others (1992, 1999a, 1999b), Carkeet and others (2001), Swanson and others (2002, 2003), Bartholomay 

and Twining (2010), and Bartholomay and others (2015).
Geochemistry Data 25

tac18-1192_fig09

9

8

7

6

5

2

1

99 98

97

90

89 87

86

85

83

82 65

57 36

32

31

29

27

26

24

23

22

20

19

18

17

15

14

12

11

3A

T3

T1

RP

N9 N8

N6 N7

125

124

120

116

115

109 108

107

105

104

103

102

101

100

M7S M3S

N13

FS2

BFW

126b

110A

P&W2

IET1

Hwy 2

EBR1

CFA2

CFA1

ANP9

ANP8

ANP6

Site9

Site4

INEL1 WS

Site19

Site17

Site14

Area II

SE of AC

NPR Test

PSTF Test

No Name 1

AC

LR1

AT1

119 117

88

113 112

N12

N10N11

T2

TD

N2

KBF

134

135

M2051

Hwy3

INEL1 10,300 & 2,000-ft

Big Lost River

Birch Creek

Little Lost River

Howe

Terreton

Monteview

Atomic City

Idaho National Laboratory

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°0' 112°45' 112°30'

44°

00'

43°

45'

43°

30'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

Site14

CFA2

INEL1

North INL Area

Northeast INL Area

Southeast INL Area

Central INL Area

Northwest INL Area

Southwest INL Area

Regional groundwater

Birch Creek Valley

Geothermal water

Deep groundwater

Contaminated groundwater

Groundwater site

Wells and spatially defined areas, 

Idaho National Laboratory and 

vicinity

Natural

groundwater

EXPLANATION

Figure 9. Wells and spatially defined areas at the Idaho National Laboratory and vicinity, eastern Idaho.
26 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 5. Quality-control samples collected at Idaho National Laboratory and vicinity, eastern Idaho.

[Shaded rows indicate bailed samples. Report: Includes only those reports that collected quality-control data discussed in this report. For example, 

replicates were collected for groundwater samples by Ott and others (1994), but only surface-water results from Ott and others (1994) are discussed 

in this report. Consequently, the replicate data from Ott and others (1994) are not discussed. Constituents analyzed from replicates: Ca, calcium; 

Cl, chloride; F, fluoride; Mg, magnesium; NO3, nitrate; K, potassium; SiO2, silica; Na, sodium; SO4, sulfate; Al, aluminum; Ba barium; B, boron; 

Cr, chromium; Fe, iron; Li, lithium; Mn, manganese; Sr, strontium; 3H, tritium; CFC, chlorofluorocarbon; He, helium; δ3He, helium-3/helium-4; 

δ2H, hydrogen-2/hydrogen-1; δ18O, oxygen-18/ oxygen-16; δ13C, carbon-13/carbon-12; δ34S, sulfur-34/sulfur-32; δ15N, nitrogen-15/nitrogen-14; U, uranium; 234U/238U, uranium-234/ uranium-238. Numbers in parentheses indicate number of replicates from which the constituent was analyzed. Abbreviations:

RPD, relative percent difference; RSD, relative standard deviation; NAD, normalized absolute difference (reported as a z-value in many of the reports 

referenced); NWQL, U.S. Geological Survey National Water Quality Laboratory; RESL, U.S. Department of Energy Radiological and Environmental Sciences 

Laboratory]

Report

Number 

of replicate 

samples

Number 

of blank 

samples

Constituents analyzed 

from replicates

Statistical method 

used for calculating 

reproducibility

Knobel and others, 1992 1

3 0 Ca,Mg,Na,K,SiO2,Cl,SO4,F,NO3,Al,Ba,Cr,Fe,Li,Mn,Sr,3H RPD, NAD

Liszewski and Mann, 1993 2

47 4 F(34), Cr(22), Ba(3), Fe(3), Mn(3), Sr(3), Al(2), Li(1) RPD

Busenberg and others, 1998, 

2000

3

149 0 CFC-11, CFC-12, CFC-113 RSD

Busenberg and others, 2000 4

6 0 He, δ3He RSD, NAD

Knobel and others, 1999a 4 0 Ca,Mg,Na,K,SiO2

,Cl,SO4,F,NO3,Al,Ba,Cr,Fe,Li,Mn,Sr,δ2H,δ18O,

δ13C,δ34S,δ15N,3

H

NAD

Knobel and others, 1999b 4 1 Ca,Mg,Na,K,Cl,SO4

,NO3,Al,Ba,Cr,Fe,Mn,3H NAD

Carkeet and others, 2001 1 0 Ca,Mg,Na,K,SiO2

,Cl,SO4,F,NO3,Al,Ba,Cr,Fe,Li,Mn,Sr,δ2H,δ18O,

δ13C,3

H

NAD

Carkeet and others, 2001 5

5 0 Ca,Mg,Na,K,SiO2,Al,Ba,Cr,Fe,Mn,Sr NAD

Roback and others, 2001 1 6

2+ U, 234U/238U NAD

Swanson and others, 2002 5

4 1 Ca,Mg,Na,K,SiO2,Ba,Fe,Mn,Sr NAD

Swanson and others, 2003 1 0 Ca,Mg,Na,K,SiO2,Cl,SO4,F,NO3,Ba,Cr,Fe,Mn,Sr,δ2H,δ18O,δ13C,3H NAD

Swanson and others, 2003 5

4 0 Ca,Mg,Na,K,SiO2,Ba,Cr,Fe,Mn,Sr NAD

Bartholomay and Twining, 

2010

7

8 2 Ca,Mg,Na,K,SiO2

,Cl,SO4,F,NO3,Al,Ba,Cr,Fe,Li,Mn,Sr,δ2H,δ18O, 

δ13C,3

H

RPD, NAD

Rattray and Ginsbach, 2014 1 0 Ca,Mg,Na,K,SiO2

,Cl,SO4,F,NO3,Al,Fe,Mn RSD

Rattray and Ginsbach, 2014 1 0 Ca,Mg,Na,K,SiO2

,Cl,SO4,F,NO3,Al,Ba,B,Cr,Fe,Li,Mn,Sr,δ2H,

δ18O,δ13C,3

H

RSD, NAD

Bartholomay and others, 

2015

8

16 7 Ca,Mg,Na,K,SiO2,Cl,SO4,F,NO3,Al,Ba,Cr,Fe,Li,Mn,Sr,δ2H,δ18O,δ 13C,3

H

RPD, NAD

Rattray, 2015 9

1 0 Ca,Mg,Na,K,SiO2,Cl,SO4,F,NO3,Al,Ba,B,Cr,Fe,Li,Mn,Sr,δ2H,

δ18O,δ13C,3

H

RSD, NAD

1

Two replicates were only of 3H. Four 3H results were obtained from the three replicates, two each from the NWQL and RESL (table 2).

2

Does not include bailed samples (Mann, 1996) or four samples from Knobel and others (1999a).

3

Only includes replicate data for sites in table 12 and excludes contaminated data (Busenberg and others, 2001).

4

Only five replicates for δ3He.

5

Replicate used for interlaboratory comparison.

6

Multiple, but unknown number, of field blanks were collected and analyzed. 

7

Only three replicates for δ13C and 3H.

8

Only five replicates for δ2H and δ18O, three for 3H, and two for δ13C.

9

Also discussed two replicates from Rattray and Ginsbach (2014).
Geochemistry Data 27

Table 6. Chemical constituents with a replicate result exceeding the acceptance 

criteria.

[Chemical constituents in bold did not meet the acceptance criteria for the collective set of 

replicates. Abbreviations: CFC, chlorofluorocarbon; NWQL, U.S. Geological Survey National 

Water Quality Laboratory; LSC, liquid scintillation counting]

Chemical 

constituent

Total 

number of 

replicate 

results

Number of 

replicate results 

exceeding 

acceptance 

criteria

Replicate

results meeting 

acceptance

criteria

(percent)

Magnesium (Mg)1 13 1 92

Fluoride (F)2 24 1 96

Aluminum (Al)2 24 3 88

Iron (Fe)2 24 1 96

Manganese (Mn)2 24 2 92

Chloride (Cl) 14 1 93

Sulfate (SO4

) 14 1 93

Fluoride 44 11 75

Aluminum 15 4 73

Chromium (Cr) 36 7 81

Iron 17 8 53

Nitrogen-15/nitrogen-14 (δ15N) 4 1 75

Tritium (3

H) (NWQL, LSC) 12 2 83

Helium-3/helium-4 (δ3

He) 5 2 60

CFC-11 145 28 81

CFC-12 120 21 83

CFC-113 112 67 40

1

Replicates used for interlaboratory comparison.

2

Replicates collected with bailers from wells equipped with multi-level monitoring 

system.

The replicate results for F probably did not meet the 

acceptance criteria due to the generally small concentrations of 

F in replicates, because relative variability generally increases 

as concentrations decrease. Replicate results for Al, Cr, and 

Fe exceeded the acceptance criteria in several reports, and 

the poor reproducibility of these constituents indicates that 

they generally have a large variability compared to most other 

constituents. One of four replicates had a result for δ15N that 

exceeded the acceptance criteria for individual replicates, but 

these are too few results to confidently assess the variability 

of δ15N.

Tritium results for two replicates, analyzed by liquid 

scintillation counting by NWQL, exceeded the acceptance 

criteria for individual replicate samples. One result had a 

NAD of 2.12 that was only slightly larger than the acceptance 

criteria (≤1.96). The other tritium result was for samples 

with activities of 27,600 and 29,600 pCi/L and analytical 

uncertainties (1σ) of 220 and 450 pCi/L. Although the NAD 

for these tritium activities is large (NAD = 4.0), the RPD of 

measurements of these large activity samples is relatively 

small (RPD = 7 percent). Consequently, even though tritium 

results exceeded the acceptance criteria for the collective 

set of replicates, the reproducibility of tritium seems to be 

quite good.

The percentage of acceptable replicate results was 

60 percent for δ3He (table 6), which was less than the 

acceptance criteria (≥90 percent) for the collective set of 

replicates. Although the variability in replicate measurements 

of δ3He was larger than the acceptance criteria, the effect 

of this variability on interpretation of δ3He values was 

insignificant. The δ3He values were used to calculate Rs/Ra

values (appendix 2, eq. 2-11), where Rs is the 3He/4He of an 

environmental sample and Ra

 is the 3He/4He of air, and the 

maximum variability of Rs/Ra values for replicate samples was 

less than 1.8 percent.

The percentage of acceptable replicate results was 81 and 

83 percent for CFC-11 and CFC-12, respectively, and 40 percent 

for CFC-113 (table 6). The standard deviation of repeated 

measurements for the instrument used to measure CFCs was 

less than 3 percent (Busenberg and others, 1998). This indicates 

that the low reproducibility of the CFC samples probably 

was due to difficulties in sample collection, storage, and (or) 

shipping. Analytical precision for measurement of CFCs was 

about 50 percent at the detection limits of about 1 picogram 

per kilogram (pg/kg) and about 3 percent for concentrations 

greater than 25 pg/kg (Busenberg and others, 1998). Most 

concentrations of CFC-113 were less than 25 pg/kg and many 

were near the detection limit. These low concentrations were 

probably the reason that CFC-113 had such low reproducibility.
28 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Reproducibility for Bailed Groundwater Samples

The four constituents with a result that exceeded the 

acceptance criteria for reproducibility in bailed groundwater 

samples were F, Al, Fe, and Mn. The percentage of acceptable 

results for these four constituents was 96 percent for F and Fe, 

92 percent for Mn, and 88 percent for Al (table 6). Aluminum 

was the only constituent that did not meet the acceptance 

criteria for reproducibility for the collective set of replicates 

and, as stated above, reproducibility is smaller and variability 

is larger for Al than for most other constituents.

Interlaboratory Comparison

Replicates collected for interlaboratory comparison 

of analytical results from the NWQL and ISU laboratories 

(Carkeet and others, 2001; Swanson and others, 2002, 2003) 

were analyzed for 11 chemical constituents (cations, silica, 

and metals) (table 5). All replicate results met the acceptance 

criteria for an individual replicate except for one result for 

Mg, which had an NAD of 2.03 that slightly exceeded the 

acceptance criteria of less than or equal to 1.96. However, 

the percentage of replicate results for Mg that met the 

acceptance criteria was 92 percent (table 6), which meets the 

acceptance criteria for the collective set of replicates. These 

results indicate that there was minimal variability and good 

reproducibility between the analytical results from NWQL 

and ISU.

Bias

Field blanks were collected with pumped and bailed 

groundwater samples and equipment blanks were collected 

with bailed groundwater samples. Field blanks were 

prepared at the sample site and included any contamination 

from the source solution, sample bottles, filter capsules 

and preservatives (if required), ambient conditions, and 

sample storage. Equipment blanks included all sources 

of contamination associated with field blanks plus any 

contamination from portable sampling equipment (Rattray, 

2012, 2014). The frequency and magnitude of contamination 

bias in the environmental samples was evaluated using order 

statistics and the binomial probability distribution (appendix 2, 

eq. 2-9).

Pumped Groundwater Samples

Analytical results for six field blanks collected with 

pumped groundwater samples and for multiple field blanks 

collected with U samples were reported (table 5). Ba and Cr 

were analyzed from three blanks, Ca, Mg, Na, K, F, Fe, and 

Mn were analyzed from two blanks, and SiO2, Cl, SO4, NO3, 

Al, and Sr were analyzed from one blank (Liszewski and 

Mann, 1993; Knobel and others, 1999b; Swanson and others, 

2002). Concentrations of U in field blanks were small, and 

concentrations of all other chemical constituents in blanks 

were less than the reporting level except for one result each for 

Ca (2.9 mg/L), Ba (2 μg/L), and Cr (0.6 μg/L).

A statistical analysis was not possible for those 

constituents with only one measurement from the blank 

samples, but for constituents with two (Ca, Mg, Na, K, Fe, 

Mn) or three measurements (Ba, Cr) a statistical analysis 

was done using order statistics and the binomial probability 

distribution (Rattray, 2012, 2014). The analysis indicated 

that at a confidence level of 78 percent (Ba, Cr) or 64 percent 

(Ca, Mg, Na, K, Fe, Mn) at least 60 percent of the pumped 

groundwater samples had a contamination bias less than 

the largest measurement from a blank sample. The largest 

measurements from blank samples were 2.9 mg/L for Ca, 

2 μg/L for Ba, and 6 μg/L for Cr and the analytical reporting 

levels for Mg, Na, K, Fe, and Mn. These results indicate 

that some pumped groundwater samples may have a small 

contamination bias for Ca, Ba, and Cr. The maximum 

contamination bias for U was reported as less than 0.3 percent 

(Roback and others, 2001).

Bailed Groundwater Samples

Four field and five equipment blanks were collected 

with the bailed groundwater samples (table 5). Four field 

blanks were analyzed for Na, Cl, SO4, Cr, and NO3 and 

two field blanks were also analyzed for Ca, Mg, K, SiO2, 

F, Al, Ba, Fe, Li, Mn, Sr, and U. Results for all chemical 

constituents analyzed from the field blanks were less than the 

reporting level except for two results each for Na (0.215 and 

0.415 mg/L), Cl (16E0.16 and 0.328 mg/L), and SiO2 (1.01 

and 1.29 mg/L). Five equipment blanks were analyzed for 

Na, Cr, and NO3, four equipment blanks were analyzed for 

Cl, two equipment blanks were analyzed for SO4, and one 

equipment blank was analyzed for Li. Results for all chemical 

constituents analyzed from the equipment blanks were less 

than the reporting level (Bartholomay and others, 2015).

For statistical analysis, the equipment blanks were treated 

as field blanks. A statistical analysis was not possible for 

those constituents with only one measurement from the blank 

samples, but for constituents with two (Ca, Mg, K, SiO2, F, 

Al, Ba, Fe, Mn, Sr, and U), three (Li), six (SO4), eight (Cl), 

or nine (Na, NO3, Cr) measurements, a statistical analysis 

was done using order statistics and the binomial probability 

distribution (Rattray, 2012, 2014). The analysis indicated that, 

at a confidence level of 78 percent (Li) or 64 percent (Ca, 

Mg, K, SiO2, F, Al, Ba, Fe, Mn, Sr, U), at least 60 percent of 

the bailed groundwater samples had a contamination bias less 

than the largest measurement from a blank sample, and at a 

confidence level of 96 (Na, NO3, Cr), 94 (Cl), or 88 (SO4) 

percent at least 70 percent of the bailed groundwater samples 

had a contamination bias less than the largest measurement 

16E indicates an estimated result.
Sources of Chemical and Isotopic Constituents 29

from a blank sample. The largest measurements from blank 

samples were 0.415 mg/L for Na, 0.328 mg/L for Cl, and 

1.29 for SiO2 and were less than the analytical reporting levels 

for Ca, Mg, K, SO4, NO3, F, Al, Ba, Cr, Fe, Li, Mn, Sr, and U. 

These results indicate that some bailed groundwater samples 

may have a small contamination bias for Na, Cl, and SiO2.

Charge Balance

Calculation of the charge balance of a sample provides 

an indication of the accuracy of major ion analyses for 

that sample. The charge balance of samples was calculated 

(appendix 2, eq. 2-10) from concentrations, in milliequivalents 

per liter (meq/L), of the major ions. Charge balance errors 

of 5 percent or less (absolute value) are generally considered 

acceptable for analyses of water samples (Freeze and Cherry, 

1979), although larger errors may be acceptable if the sum 

of ions is less than 5 meq/L (Hem, 1992). Charge balance 

errors exceeding 5 percent may indicate analytical errors or 

omission of important ionic species from analysis (Freeze and 

Cherry, 1979).

Of the 165 water samples with a complete suite of 

major ion analyses, 160 had charge balance errors of less 

than 5 percent (table 13). The five water samples with charge 

balance errors larger than 5 percent were from NRF 13, 

USGS 87, USGS 90, TDD 3, and USGS 134, and three of 

these samples were contaminated groundwater (NRF 13, 

USGS 87, and USGS 90). The charge balance errors for 

samples from USGS 87, USGS 90, TDD 3, and USGS 134 

ranged from 6.5 to 7.8 percent (absolute value). These errors 

are slightly larger than the 5 percent criteria for charge balance 

errors, but are acceptable for the purposes of this report. The 

sample collected from NRF 13 had a charge balance error of 

18.8 percent, which makes the major ion chemistry of this 

sample suitable only for identifying the distribution of wastes 

in the ESRP aquifer at NRF.

Sources of Chemical and Isotopic 

Constituents

The geochemistry of groundwater in the ESRP aquifer 

at the INL reflects the sources of chemical and isotopic 

constituents, which includes the chemistry of the various 

sources of recharge and any physical and chemical processes 

occurring in the aquifer. The chemistry of recharge sources 

and the physical and chemical processes influencing chemical 

and isotopic compositions in the aquifer must be understood 

in order to make reliable interpretations, based on their 

compositions in surface water and groundwater, about sources 

of recharge, mixing of water, and groundwater flow directions.

Some important physical and chemical processes include 

solution of gases, mixing of water, evaporation, alpha (α) 

recoil, water-rock interaction, isotope fractionation, and 

radioactive decay. Redox reactions may be important in some 

areas, either from oxidation of minerals with iron and (or) 

sulfur in a reduced state (Wood and Low, 1988), upwelling 

of anoxic geothermal water (Rattray, 2015), or mixing with 

anoxic water in wetlands (Rattray and Ginsbach, 2014). These 

physical and chemical processes provide sources (and sinks) 

of dissolved gases and inorganic chemicals, affect stable 

and radioactive isotope compositions, control the percentage 

of Heterr in groundwater, and influence the compositions of 

environmental tracers used to estimate the age of groundwater.

Sources of Inorganic Chemical Constituents

Dissolved Gases

Sources of dissolved gases in the ESRP aquifer may 

include exchange of gases between the aquifer and the 

atmosphere, soil zone, or unsaturated zone; release of gases 

into groundwater from the aquifer matrix; recharge of 

surface water that equilibrated with atmospheric, soil zone, 

or unsaturated zone gases; upward movement of geothermal 

water; and chemical or biological reactions in the aquifer 

(Busenberg and others, 2001; Rattray and Ginsbach, 2014).

Carbon-14 activities and DO, CO2, 3He, 4He, CFCs, and 

SF6 concentrations in the ESRP aquifer typically were not in 

equilibrium with current atmospheric, soil zone, or unsaturated 

zone gas concentrations and provided evidence that the aquifer 

at the INL generally behaved as a closed system (Busenberg 

and others, 1993; Schramke and others, 1996; Busenberg and 

others, 2001). Geochemical modeling of the ESRP aquifer 

upgradient of the INL generally supported this interpretation, 

but also demonstrated that the aquifer behaved as an open 

system, with respect to some gases, in areas where recharge 

from geothermal or surface water occurred (Rattray and 

Ginsbach, 2014; Rattray, 2015). Recharge of surface water, 

as infiltration from lakes, ponds, irrigation water, or streams, 

potentially may add He, CFCs, SF6, and oxygen from the 

atmosphere and unsaturated zone, as well as CO2 produced 

in the soil zone, to groundwater. Upward movement of 

geothermal water may be a source of anoxic water, helium, 

methane (CH4), ammonia (NH3), and hydrogen sulfide (H2S).

Chemical, biological, and physical processes and reactions 

may affect the concentrations of dissolved gases in the aquifer. 

Such processes and reactions include anaerobic degradation of 

CFCs under reducing conditions, microbial reduction of NO3

-

to N2 under anoxic conditions (Busenberg and others, 2001), 

consumption of oxygen through oxidation-reduction reactions, 

consumption of CO2 through silicate and carbonate reactions 

(Rattray and Ginsbach, 2014), production of 3He as a daughter 

product of radioactive decay of 3H, and release of 4He from 

the aquifer matrix by α-particle decay of 238U, 235U, and 232Th 

and their daughter products (Solomon, 2000; Solomon and 

Cook, 2000). 
30 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

The ESRP aquifer is a well-oxygenated system, so 

reducing and anoxic conditions occur only locally in the ESRP 

aquifer. The rate of most silicate reactions is extremely slow, 

but because silicate rocks are so abundant in the ESRP aquifer 

silicate reactions may affect the partial pressure of CO2. 

Consequently, modification of dissolved gas concentrations 

in the ESRP aquifer from chemical, biological, or physical 

processes and reactions is largely from consumption of 

CO2 from carbonate and silicate reactions, the production 

of He from radioactive decay, and downward transport of 

atmospheric, soil zone, or unsaturated zone gases to the 

aquifer in infiltrating surface water.

Major Ions and Dissolved Metals

Potential sources of inorganic chemical constituents in 

the ESRP aquifer, excluding stream and shallow groundwater 

sources of recharge, include water-rock interaction, 

anthropogenic inputs, and geothermal water (table 7). 

Water-rock interaction, which may be a source or sink of 

inorganic chemical constituents, refers to the dissolution 

or precipitation of minerals or other solid phases and ion 

exchange processes. Plausible water-rock interactions in 

the ESRP aquifer include carbonate and silicate reactions, 

dissolution of evaporite minerals, oxidation of pyrite, and 

cation exchange (Wood and Low, 1988; McLing, 1994; 

Schramke and others, 1996; Knobel and others, 1997; 

Busenberg and others, 2001; Rattray and Ginsbach, 2014; 

Rattray, 2015). However, except for volcanic glass, which is 

reactive, silicate reactions may be a small source of inorganic 

chemical constituents in the ESRP aquifer because most 

silicate minerals dissolve slowly in groundwater due to the 

kinetics of a rate-limiting reaction step or steps (Lasaga and 

others, 1994). This interpretation is supported by petrographic 

analyses that show most mineral grains in basalt, in the 

shallow part of the ESRP aquifer, appear fresh and unaltered 

(Nace and others, 1956). Geochemical modeling also indicated 

only small amounts of silicate phases need to dissolve to 

produce the chemistry of groundwater in the shallow ESRP 

aquifer (Busenberg and others, 2001; Rattray and Ginsbach, 

2014; Rattray, 2015).

Anthropogenic inputs primarily are derived from irrigated 

areas adjacent to the INL and industrial waste disposal from 

sites at the INL. Anthropogenic sources of chemical and 

isotopic constituents include industrial wastes disposed at the 

INL, agricultural wastes from fertilizer, cattle manure, and 

legume crops tilled under at the end of the growing season 

(Rupert, 1996), road salt and salt brine (Ken Hahn, Idaho 

Transportation Department, oral commun., October 6, 2015; 

U.S. Department of Energy, 2011), and atmospheric deposition 

of tritium, carbon-14, and other environmental tracers. 

Anthropogenic inputs from domestic septic system wastes are 

negligible (Rupert, 1996). The predominant waste constituents 

disposed at the INL have been Na, Cl, SO4, NO3, and 3H 

(Davis and others, 2013). The disposal methods, years of 

disposal, and wastes disposed for various facilities at the INL 

are shown in table 8. Agricultural wastes may be significant 

sources of NO3, K, and Cl (Rupert, 1996; Appelo and Postma, 

2005; Shakhashiri, 2015), and road salt and road deicing salt 

brine may be sources Ca, Na, Mg, and Cl (U.S. Department of 

Energy, 2011). Deposition of environmental tracers that were 

or are anthropogenic in origin include 3H, 14C, CFCs, and SF6

(Michel, 1989; Plummer and others, 1993; Busenberg and 

Plummer, 2000).

Geothermal water beneath the ESRP aquifer is anoxic 

and has large concentrations of HCO3, Na, SO4, B, Fe, and 

Li (INEL-1 10,300 ft, tables 12–14). Consequently, a small 

amount of upwelling geothermal water that mixes with 

shallow ESRP groundwater can produce redox reactions and 

noticeable changes in major ion and dissolved metal chemistry 

(Rattray, 2015).

Classification of Water Types

Water types, or hydrochemical facies, of water 

samples may be used to indicate broad differences in 

the major ion chemistry of water samples, the chemical 

evolution of groundwater, and as an indicator of mixing 

of source waters. Water at the INL and vicinity was 

classified into hydrochemical facies based on the relative 

percentage of individual cations and anions. For example, 

cation (Ca+2, Mg+2, and Na+ + K+) and anion (HCO3

-

+ CO3

-2, Cl-

, and SO4

-2) concentrations (in units of 

milliequivalents per liter) of water samples were plotted 

on trilinear (Piper) diagrams (Plummer and others, 2004b), 

with the cations and anions plotted as a percentage of the 

total cation or total anion concentrations (fig. 10A). The 

Na-HCO3 hydrochemical facies was defined as water in 

which Na+ + K+ makes up 50 percent or more of the total 

cations and HCO3

-

 + CO3

-2 makes up 50 percent or more of 

the total anions (Rattray and Ginsbach, 2014). Similarly, the 

Mixed Cation-Mixed Anion hydrochemical facies is defined 

by water in which no cation makes up 50 percent or more of 

the total cations and no anion makes up 50 percent or more of 

the total anions.
Sources of Chemical and Isotopic Constituents 31

Table 7. Potential sources of inorganic chemical constituents to the eastern Snake River Plain aquifer, Idaho National Laboratory and 

vicinity, eastern Idaho.

[The sources of inorganic chemical constituents are based on information in Barraclough and others (1967); Schoen (1972); Roberson and Schoen (1973); 

Robertson and others (1974); Parliman (1983); Deer and others (1983); Mann (1986); Wood and Low (1988); Hem (1992); McLing (1994); Knobel and 

others (1997); McNutt (2000); Osmond and Cowart (2000); Busenberg and others (2001); Rattray and Ginsbach (2014); Rattray (2015); Shakhashiri (2015). 

Abbreviations: ATRC, Advanced Test Reactor Complex; INTEC, Idaho Nuclear Engineering and Technology Center; MFC, Materials and Fuels Complex; 

NRF, Naval Reactors Facility; RWMC, Radioactive Waste Management Complex; TAN, Test Area North; >, greater than]

Inorganic chemical 

constituent

Potential sources of inorganic 

chemical constituents

Calcium

Dissolution of carbonate (calcite, aragonite, dolomite), silicate (primarily from basaltic glass and plagioclase, minor 

amounts from pyroxene), evaporite (gypsum, anhydrite), fluoride (fluorite), and phosphate (apatite, fluorapatite) 

minerals; agricultural soil amendments (inorganic fertilizer, gypsum, lime); discharge of wastewater at the ATRC.

Magnesium

Dissolution of carbonate (magnesium-calcite, dolomite) and silicate (primarily from basaltic glass, minor amounts 

from olivine and pyroxene) minerals; agricultural soil amendments (lime); discharge of wastewater (at ATRC); 

road deicing salt brine.

Sodium

Dissolution of silicate (primarily from rhyolitic glass, basaltic glass, and plagioclase) and evaporite (halite) minerals; 

agricultural soil amendments (inorganic fertilizer, manure); sewage; road salt; ion exchange reactions; discharge 

of wastewater; geothermal water.

Potassium

Dissolution of silicate (primarily from rhyolitic and basaltic glass, possibly minor amounts from potassium feldspar 

and biotite) and evaporite (sylvite) minerals; agricultural soil amendments (inorganic fertilizer, manure); sewage; 

geothermal water.

Silica Dissolution of silicate (primarily from rhyolitic glass, basaltic glass, and plagioclase, minor amounts from olivine, 

pyroxene, and possibly potassium feldspar and biotite) minerals.

Bicarbonate and 

carbonate

Dissolution of carbonate (calcite, dolomite) and silicate (primarily from rhyolitic glass, basaltic glass, and 

plagioclase, minor amounts from olivine, pyroxene, and possibly potassium feldspar) minerals; agricultural soil 

amendments (lime); discharge of wastewater (from decomposition of organic compounds or sewage); geothermal 

water; dissociation of carbonic acid.

Chloride Dissolution of evaporite (halite) minerals; agricultural soil amendments (inorganic fertilizer, manure); sewage; road 

salt and road deicing salt brine; discharge of wastewater; atmospheric deposition.

Sulfate

Dissolution of evaporite (gypsum, anhydrite) minerals; oxidation of sulfide minerals (pyrite); agricultural soil 

amendments (inorganic fertilizer, gypsum); discharge of wastewater (at MFC, NRF, ATRC, and INTEC); 

geothermal water; atmospheric deposition.

Fluoride Dissolution of silicate (possibly from rhyolitic glass, minor amounts from micas) minerals, fluoride (fluorite), and 

phosphate (fluorapatite) minerals; discharge of wastewater (at INTEC); geothermal water.

Nitrate Agricultural soil amendments (inorganic fertilizer, manure); sewage; animal waste; legumes; plant debris; discharge 

of wastewater; atmospheric deposition.

Aluminum Dissolution of silicate (primarily from rhyolitic glass, basaltic glass, and plagioclase, possibly minor amounts from 

potassium feldspar and biotite) minerals.

Barium Dissolution of carbonate (witherite) and sulfate (barite) minerals; discharge of wastewater (at ATRC).

Boron Dissolution of evaporite (borax) minerals; agricultural soil amendments (inorganic fertilizer); geothermal water.

Chromium Discharge of wastewater (ATRC and MFC) and leaching of solid wastes (RWMC).

Iron

Dissolution of silicate (primarily from basaltic glass, minor amounts from olivine and pyroxene) minerals, oxidation 

of sulfide (pyrite) minerals; agricultural soil amendments (inorganic fertilizer); geothermal water; relatively 

insoluble in oxic water.

Lithium Dissolution of silicate (mica) minerals; geothermal water.

Manganese Small amounts in carbonate rocks (limestone, dolostone) and a significant constituent of basalt; agricultural soil 

amendments (inorganic fertilizer); geothermal water.

Strontium

Dissolution of carbonate rocks (limestone, dolostone) and silicate (primarily from plagioclase and potassium 

feldspar) minerals; discharge of wastewater or leaching of solid waste (particularly at INTEC, but also TAN, 

MFC, ATRC, and RWMC).

Uranium

Dissolves in minor amounts from most rocks, with greater abundance in igneous (felsic > mafic) than sedimentary 

rocks; discharge of wastewater or leaching of solid waste (at MFC, INTEC, CFA, and RWMC); relatively 

insoluble in anoxic water.
32 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 8. Waste constituents disposed to the subsurface, Idaho National Laboratory, eastern Idaho.

[Information from Davis and others (2013), U.S. Department of Energy (2011), Lenhard and others (2004), Fromm (1995) and Busenberg and others (2001). 

Locations of site facilities shown on figure 3B. Waste constituents disposed: Includes only constituents that are discussed in this report. Abbreviations: Ba, 

barium; Ca, calcium; Cl, chloride; CFC, chlorofluorocarbon; Cr, chromium; F, fluoride; 3H, tritium; Mg, magnesium; Na, sodium; NO3, nitrate; SO4, sulfate; Sr, 

strontium; U, uranium]

Site 

facility

Historical and current 

disposal methods Years Waste constituents disposed

Advanced Test Reactor 

Complex

Wells, infiltration, and evaporation ponds 1952 to present Ca, Mg, Na, Cl, SO4

, NO3, Cr, Ba, 3H, 90Sr, CFCs

Central Facilities Area Drain field, ponds, landfills1 1952 to present Na, Cl, NO3

, U isotopes

Idaho Nuclear and Technology 

Engineering Center

Wells, infiltration ponds and trenches, 

buried waste

1952 to present Na, Cl, SO4

, F, NO3, 3H, 90Sr, U 

isotopes, CFCs

Materials and Fuels 

Complex

Ditches, lagoons, canals, pit 1960 to present Na, Cl, SO4

, N, Cr, 90Sr, 238U 

Naval Reactors Facility Ponds, ditch 1953 to present Na, Cl, SO4

, NO3, 3H, CFCs

Radioactive Waste Management 

Complex

Burial in landfill, trenches, and pits;1

septic systems

1952 to present Na, Cl, NO3, Cr, organic compounds, 14C, 90Sr, U isotopes, CFCs

Test Area North (includes the 

Technical Support Facility)

Well, infiltration ponds 1953 to 2007 Na, Cl, organic compounds, 3

H, 90Sr

1

Solid waste. 

The hydrochemical facies of surface water and 

groundwater samples from the study area were plotted on a 

trilinear diagram (fig. 10A), and oval areas representing most 

natural groundwater at the INL were included on this figure 

to compare where various source waters or other groundwater 

at the INL plot relative to natural groundwater. The spatial 

distribution of the hydrochemical facies of surface water and 

groundwater in the study area is shown in figure 10B.

Interpretation of Isotope Ratios

Geochemistry data from groundwater at and near the 

INL include stable and radioactive isotope data. Isotopic data 

were reported as isotope ratios using delta notation (δ2

H, 

δ18O, δ13C, δ34S, δ15N, δ3He), mass ratios (87Sr/86Sr, 3He/4He), 

activity ratio (234U/238U), and activities (3H, 14C). Differences 

in stable isotope ratios result from isotope fractionation and 

exchange, and differences in radioisotopes result primarily 

from radioactive decay (the spontaneous emission of particles 

and radiant energy from the unstable nuclei of a radioactive 

atom or isotope; Faure, 1986) and (or) mixing of water with 

different radioisotope activities. Radioactive, or parent, 

isotopes that decay may become less abundant in the aquifer 

or aquifer matrix, whereas the daughter isotopes produced 

by the decay of parent isotopes may increase in abundance. 

For example, rubidium-87 (87Rb), 238U, 234U, 3

H, and 14C are 

all unstable isotopes that undergo radioactive decay in the 

aquifer and 87Sr, 234U, 3He, and 4He are some of the daughter 

isotopes produced by radioactive decay. Isotope ratios can 

be used to identify sources of water and chemical elements, 

and radioisotopes reported as activities typically are used to 

estimate the age of groundwater (that is, the time since the 

groundwater was recharged). 

Hydrogen and Oxygen

The stable isotope ratios of hydrogen and oxygen in 

groundwater are inherited from the sources of groundwater, 

although evaporation or mixing of water can modify the 

isotope ratios. Groundwater in the study area originates largely 

from precipitation in the mountains (Rattray and Ginsbach, 

2014; Rattray, 2015), and in precipitation the stable isotopes 

of hydrogen and oxygen reflect the origin of the air mass and 

the conditions under which precipitation occurs (Benjamin 

and others, 2004). For example, in a continental air mass 

that undergoes numerous precipitation events, the δ2

H and 

δ18O values of the water vapor in the air mass (or cloud) 

become progressively depleted (lighter, smaller, or more 

negative) as fractionation and Rayleigh-type distillation causes 

precipitation to be isotopically enriched (heavier, larger, or less 

negative; Clark and Fritz, 1997). This rainout effect causes 

precipitation to become progressively lighter along the path 

of the air mass. Precipitation also may become progressively 

depleted as temperature decreases, which can occur due to 

changes in latitude, altitude, or seasons. Changes in latitude 

across the study area are not large enough to effect a change 

in temperature or the δ2

H and δ18O values of precipitation. 
Sources of Chemical and Isotopic Constituents 33

However, colder temperatures and relatively lighter δ2H and 

δ18O values in precipitation occur in the study area at high 

elevations in the mountains and during winter.

In water undergoing evaporation, δ2H and δ18O values in 

the residual water body become enriched due to isotope mass 

fractionation. This effect is readily identified on a δ2H–δ18O 

diagram (fig. 11), where the progressive increase of δ2H and 

δ18O values in the evaporated water body plots along a lower 

slope than the slope of local meteoric water lines (Clark and 

Fritz, 1997). For example, a linear regression of δ2H and δ18O 

values from Mud Lake water samples produced an evaporation 

line with a slope (δ2H = 5.35 δ18O + 38.9, r2 = 0.88) that may 

be characteristic for surface water on the ESRP near the INL 

(fig. 11). Local meteoric water lines (LMWL) for summer and 

winter precipitation in the mountains east, north, and west of 

the study area were developed by Benjamin and others (2004), 

and these LMWL, and the δ2H and δ18O values for surfacewater and groundwater samples collected from the study area 

(table 15), are shown in figure 11. An oval region representing 

most natural groundwater at the INL also was included in 

figure 11 to compare where various potential source waters, 

and other groundwater at the INL, plot on the graph relative to 

natural groundwater.

Carbon

The stable isotopes of dissolved inorganic carbon in 

groundwater are initially influenced by recharge water moving 

through the soil and unsaturated zones. This recharge is 

influenced by the decay of organic matter, which has typical 

δ13C values of soil CO2 (of C3-type plants typical in temperate, 

high-latitude regions) estimated to range from about -24 to 

-30 permil (Clark and Fritz, 1997), although Wood and Low 

(1988, p. 22) estimated that δ13C values of soil CO2 in upland 

tributary basins to the INL were about -22 permil. On the 

ESRP at the INL, Wood and Low (1988) noted that the δ13C 

values of CO2 in soil gas averaged -14 permil and Conrad and 

DePaolo (2004) measured background (uncontaminated) δ13C 

values from the shallow (30–230 ft depth) unsaturated zone at 

the RWMC and determined an average δ13C value for soil CO2

of -18.2 permil.

As water enters and moves through the soil and 

unsaturated zones, CO2 dissolves in groundwater and 

fractionation of the carbon isotopes produces a δ13C value 

for bicarbonate that is enriched by about 9 permil relative 

to the soil or unsaturated zone CO2 (Clark and Fritz, 1997). 

Water-rock interaction with carbonate rocks in the soil, 

unsaturated, and saturated zones may also influence δ13C 

values. Marine carbonate rocks typically have δ13C values 

near zero (Clark and Fritz, 1997), and reported δ13C values 

of microbial limestone in the Beaverhead Mountains had 

δ13C values ranging from -2.8 to 5.1 permil (Hodges, 2006). 

Consequently, dissolution of carbonate rocks will cause δ13C 

values in groundwater to become heavier. Because δ13C values 

fractionate to slightly heavier values in calcite precipitating 

from groundwater (Clark and Fritz, 1997), δ13C values in the 

residual groundwater will be lighter.

Upwelling of geothermal water may also influence δ13C 

values in the ESRP aquifer. Carbon dioxide in the mantle 

has δ13C values that range from about -10 to -2 permil (Clark 

and Fritz, 1997). These values are similar to or heavier than 

δ13C values in natural groundwater at the INL, indicating 

that upwelling geothermal water that mixes with natural 

groundwater may cause the δ13C values in some natural 

groundwater to become slightly heavier.

Sulfur

The stable isotopes of sulfur can be used to determine 

sources of sulfur and, if sources of sulfur vary across the 

study area, to identify sources of water. Potential sources of 

sulfur in the study area include dissolution of calcium sulfate 

(anhydrite or gypsum in evaporite deposits, soil amendments, 

or associated with limestone), iron sulfide (pyrite) minerals, 

and volcanic sulfur. Typical ranges of δ34S values for calcium 

sulfate are about 10–30 permil in Paleozoic and Cenozoic 

evaporites and about 0–25 permil for calcium sulfate 

associated with limestone, and the typical range for volcanic 

sulfur is about 2–15 permil (Clark and Fritz, 1997). A single 

measurement of pyrite from a vesicle in a sample of ESRP 

basalt yielded a value of -8.9 permil (Wood and Low, 1988). 

The stable isotopes of sulfur from the Snake and Boise Rivers, 

at locations where they drain Permian sulfate deposits and 

pyritized granite, respectively, had δ34S values of 14.9 and 

-6.6 permil (Wood and Low, 1988).

Nitrogen

The stable isotopes of nitrogen may be used to determine 

whether nitrogen (as nitrate) in groundwater was derived from 

inorganic fertilizer, manure, septic systems, or underwent 

denitrification. Ranges typical of δ15N values for these 

inputs are -5 to 5 permil for inorganic fertilizer and 10 to 

20 permil for manure or septic systems (Clark and Fritz, 

1997). The δ15N value for the residual fraction of nitrate that 

underwent denitrification (the nitrate remaining after N2 gas 

produced from denitrification leaves the system) increases 

as the residual fraction of nitrate decreases; δ15N values for 

the residual fraction have been reported to be as much as 

80 permil (Clark and Fritz, 1997). 
34 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig10a

PERCENT

PERCENT

PERCENT

20

20

20

40

40

40

60

60

60

80

80

80

Magnesium (Mg)

Calcium (Ca)

20

20

20

40

40

40

60

60

60

80

80

80

Sulfate (SO4

)

Chloride (Cl)

Sulfate + chloride (SO4

 + Cl)

Calcium + magnesium (Ca + Mg)

Bicarbonate + carbonate (HCO3

 + CO3

)

Sodium + potassium (Na + K)

80

80

60

60

40

40

20

20

Ca Na Cl

Mg SO4

HCO3

Mixed

Cation

Mixed

Anion

7

65

ML 27

ML 25

BLR

M2051

Hwy3

INEL-1 10,300 feet

ML 57

INEL-1 2,000 feet 112 113

22

▲ Surface water

Tributary valley groundwater

Regional groundwater

Geothermal water

Deep groundwater

Contaminated groundwater

Natural groundwater

Natural groundwater at the

Idaho National Laboratory

EXPLANATION

●

■

♦

▼

A

Figure 10. Hydrochemical facies of surface water and groundwater in the study area, Idaho National Laboratory and vicinity, eastern 

Idaho. (A) Trilinear diagram showing hydrochemical facies of surface-water and groundwater samples. (Oval areas represent where 

most natural groundwater plots on the diagram, and triangular fields represent defined cation and anion hydrochemical facies.) 

(B) Spatial distribution of hydrochemical facies of surface-water and groundwater samples.
Sources of Chemical and Isotopic Constituents 35

tac18-1192_fig10b

B

Beaverhead Mountains

Pioneer

Range

Lost River Range

Lemhi Range

Mud Lake Little Lost River

Big Lost River

Birch Creek

Medicine Lodge Creek

Hamer

Terreton

Blue Dome

Spencer

Dubois

Camas

Atomic City

Arco

Howe

Monteview

Idaho National Laboratory

9

8

7

6

5

2

1

99 98

97

90

89

88

87

86

85

83

65 57 82 36

32

31

29

27

26 24

23

22

20

19

18

17

15

14

12

11

3A

T3

T1 T2

RP

N8,N9N6 N7

ML

CC

125

124

119

112 115

109 108

107

105

104

103

101

100

MSR Oar

FS2

BFW

126b

110A

P&W2

Owen

ML 9

ML 6

ML 5

ML 2

Mays

IET1

Hwy2

Hill

EBR1

CFA2 CFA1

ANP9

ANP8

ANP6

Site9

Site4

ML 59

ML 58

ML 57

ML 55

ML 34

ML 33

ML 31

ML 30

ML 29

ML 28

ML 27

ML 26

ML 24

ML 23

ML 22

ML 19

ML 18

ML 17

ML 15

ML 13

ML 12

INEL1 2,000’

LLR H

LLR C

BC BD

BLR A Site19

Site17

Site14

Fulton

Coates

BC KGS

Wheeler

W

Muffett

Lambert

Harrell

Area II

BLR LB

BLR INL

Sorenson

SE of AC

Pancheri

NPR Test

McKinney

PSTF Test

NN1

Nicholson

BLR MD

RF

RR

AC LR1

AT1

WR

ACW4

KBF

BLR M

120

117

113

116

N13 102,N2 N12

N10,N11

Hwy3

INEL1WS

ML 25

M7S

M3S

134

135

M2051

0 10 20 MILES

0 10 20 KILOMETERS

113°45' 113°30' 113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

EXPLANATION

Ca-HCO3

Na-HCO3

Ca-SO4

Mixed cation-HCO3

Mixed cation-Cl

Ca-mixed anion

Mixed cation-mixed anion

Contaminated groundwater

Surface water

Deep groundwater or 

geothermal water

CFA 1

BLR M

Site 14

Figure 10.—Continued
36 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig11

Mud Lake evaporation line

y = 5.35x - 38.9

R2 = 0.88 

-145

-140

-135

-130

-125

-120

-19.0 -18.5 -18.0 -17.5 -17.0 -16.5 -16.0 -15.5 -15.0 -14.5

δ2H, in permil VSMOW

δ18O, in permil VSMOW

Most natural

groundwater at the

Idaho National 

Laboratory 

ML 22

No Name 1

CFA 2

ML 30

15

89

126b

ML 19

ML 23

ML 31

ML 24

Pancheri

115

ML 29

EBR 1

RR 5

ML 57

ML 17

ML 9

ML 5

ML 6

65

BLR blw lwr Lincoln Blvd Br

Owen

WGS

Fulton

Muffett

Wheeler

Mays

ML 25

ANP 6

Middle 2051

BLR blw Arco

CC

PSTF Test

IET 1

ANP 9

WR

KGS

Wagoner

101

P&W2

17

Backwards projected evaporation line for Birch Creek

LMWL-winter, δ2H = 7.41 δ18O - 2.18 

LMWL-summer, δ2H = 8.49 δ18O + 14.5 

INL groundwater

Big Lost River

Little Lost River

Birch Creek

Mud Lake

Big Lost River Valley

Little Lost River Valley

Birch Creek Valley

Regional groundwater

Deep groundwater

Geothermal water

Contaminated groundwater

EXPLANATION

1σ error bars for 

data points

Figure 11. Local meteoric water lines for summer and winter precipitation, stable isotope ratios of hydrogen and oxygen 

(δ2H and δ18O, respectively) for surface-water and groundwater samples collected from the study area, evaporation lines, 

and the region that represents most δ2H and δ18O (Vienna Standard Mean Ocean Water [VSMOW]) values in natural 

groundwater at the Idaho National Laboratory, eastern Idaho. Actual values are shown in tables 3 and 15; abbreviated site 

names are shown in table 10.
Sources of Chemical and Isotopic Constituents 37

Helium

Helium, a noble gas, is chemically inert, has two stable 

isotopes (3He and helium-4 [4He]) that accumulate in aquifer 

materials through different processes (such as radioactive 

decay of U and Th in aquifer minerals and upward fluxes 

from deeper units, including the mantle), and 4He may be 

released slowly, and at a steady rate, from the aquifer matrix 

into groundwater. The unreactive chemistry of helium, 

the unique helium concentrations and 3He/4He isotopic 

ratios, or R (calculated from δ3He values in table 15 and 

eq. 2-11 for calculating Rs/Ra in appendix 2, where Rs is 

the R of an environmental sample and Ra is the R of air), 

of various waters, and the steady release rate of 4He to the 

groundwater allows helium concentrations and isotopic ratios 

in groundwater to be used to identify sources of water and 

to estimate groundwater ages. However, complications in 

using helium for these purposes may arise from transport of 

helium across aquifer boundaries due to upward diffusion of 

helium from the mantle or deep crust (Stute and others, 1992; 

Clark and Fritz, 1997) and (or) enhanced release of 4He from 

aquifers containing recently eroded sediments (Solomon and 

others, 1996; Solomon, 2000).

Concentrations of helium are about 4.5 ×10-8 cm3 at 

standard temperature and pressure per gram of fluid or solid 

(STP/g) in surface water, 10-7–10-4 cm3 STP/g in crustal 

fluids, and as large as 2.7 × 10-5 cm3 STP/g in mantle fluids 

(Clark and Fritz, 1997). Basalts of the ESRP near the INL 

have helium concentrations ranging from about 1 × 10-9

to 7 × 10-9 cm3 STP/g (of rock; Graham and others, 2009). 

Typical concentrations of helium in groundwater at the INL 

that was saturated with air, or that contained small amounts 

of excess air, were about 4.5 × 10-8–6.5 × 10-8 cm3 STP/g 

(Busenberg and others, 2001).

Helium in air has an R of 1.384 × 10-6 (Ra), and helium 

dissolved in surface water is slightly fractionated to a smaller 

R of 1.360 × 10-6 (Rsw). Helium derived from the crust is 

enriched in 4He because U and Th isotopes (described in 

section, “Uranium”) in crustal rocks go through numerous 

α-particle decay steps in the process of decaying to their final 

daughter product, and α particles are 4He molecules (Clark and 

Fritz, 1997). Crustal helium that accumulates in groundwater, 

therefore, is enriched in 4He, has an R of about 10-9–10-7 (Rc) 

(Solomon, 2000), and an Rc/Ra ranging from about 0.0007 

to 0.07. Helium derived from the mantle is enriched in 3He, 

relative to Ra, and has an R of about 1.0 x 10-5–3.0 x 10-5

(Rm) and an Rm/Ra ranging from about 7 to 21 (Clark and 

Fritz, 1997; Solomon, 2000). Increased 3He concentrations in 

groundwater also may occur from radioactive decay of natural 

or anthropogenic 3H in the groundwater, producing tritiogenic 

3

He with an R (Rt) in groundwater that will increase as long as 

significant amounts of 3H are present. Sources of significant 

amounts of tritiogenic 3He in the ESRP aquifer at the INL 

include recharge from streams and surface water used for 

irrigation during the 1950s–1970s and discharge of tritium in 

wastewater at the INL.

The various sources of helium produce different 

evolutions of helium concentrations and Rs/Ra ratios 

in groundwater. These differences were illustrated for 

groundwater samples at the INL by plotting Rs/Ra ratios 

compared to helium concentrations in figure 12. Helium 

in surface water or groundwater that is in equilibrium with 

helium in air has an Rs/Ra ratio of approximately 1 and small 

helium concentrations, although samples containing excess 

air (No Name 1; Busenberg and others, 2001) have larger 

helium concentrations. Groundwater containing crustal 

helium has helium concentrations that increase, and Rs/Ra

ratios that decrease, with increasing groundwater residence 

time, and groundwater containing mantle helium has helium 

concentrations and Rs/Ra ratios that increase with increasing 

amounts of mantle helium. The Rs/Ra ratios also increase 

in groundwater affected by tritiogenic helium. However, 

even though tritiogenic and mantle helium may both have 

large Rs/Ra ratios, they can be differentiated from each other 

because tritiogenic helium produces much smaller increases in 

helium concentrations than mantle helium.

Helium may completely or partially re-equilibrate with 

atmospheric helium in groundwater used for irrigation. Under 

these conditions, helium concentrations in the groundwater 

may decrease and, depending on the Rs/Ra ratios in the 

groundwater prior to use for irrigation, Rs/Ra ratios may 

decrease, increase, or stay the same.

Basalts of the ESRP were derived from the mantle, so 

the basalts contained helium enriched in 3He. Basalts near 

the INL have an R ranging from 2.2 × 10-5 to 2.4 × 10-5

(Rb) and Rb/Ra ratios of about 15–17 (Graham and others, 

2009), although dissolution of basalt adds very small 

amounts of helium to groundwater. Consequently, helium 

added to groundwater from dissolution of basalt should 

slightly increase the Rs/Ra ratios of the groundwater without 

a significant increase in helium concentrations (fig. 12). 

Additionally, accumulation of helium in groundwater from 

dissolution of basalt is limited to groundwater undersaturated 

with respect to the minerals in the basalt, and once 

groundwater reaches chemical equilibrium with these minerals 

this source of helium ceases. Only recharge from precipitation, 

streams, and groundwater from the tributary valleys, and 

surface water used for irrigation, all of which should be 

undersaturated with silica, should dissolve significant amounts 

of basalt.
38 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig12

0.0

2.0

4.0

6.0

8.0

3.0 6.0 9.0 12.0 15.0 18.0

Isotope ratio of helium in environmental sample divided by

isotope ratio of helium in air, as Rs/Ra

Helium concentration (10-8 cubic centimeters at STP/gram)

124(23)

109(16)

USGS 27

32.4, 9.7 (88)

ANP 9(67) Area II(72)

29(71)

22(0)

9(23)

NPR Test (8)

101(55)

1(60) 100(53)

NN1(10)

17(27)

23(57)

AT1(46)

86(40)

105(8)

5(30)

19(38)

2(34)

99(9)

P&W2(5) 98(2)

AC(24)

11(13) 8(10)

12(6)

97(6)

ML22(7) Helium in

groundwater in

equilibrium with

surface water or air 

Tritiogenic helium-3

Mantle helium 

Crustal helium-4

32(35) 103(16)

14(13)

ANP 6(15)

PSTFTest(1)

102(10)

R s/R a = 1

Includes helium

from excess air

Helium from

dissolution of basalt

(0)

Tributary groundwater

Regional groundwater

Northeast INL Area

Southeast INL Area

North INL Area

Central INL Area

Northwest INL Area

Southwest INL Area

Wastewater influenced

Terrigenic helium

EXPLANATION

Figure 12. Helium concentrations and the isotope ratios of helium (as the isotope ratio of sample to air, 

Rs/Ra) for groundwater samples, Idaho National Laboratory and vicinity, eastern Idaho. Arrows indicate how 

helium concentrations and ratios evolve for various sources of helium. STP, standard temperature and pressure.
Sources of Chemical and Isotopic Constituents 39

Strontium

The isotope ratio, 87Sr/86Sr, can be used in groundwater 

studies to identify groundwater source areas, flow directions, 

and mixing (Johnson and others, 2000) because Sr is readily 

soluble in groundwater, 87Sr/86Sr values often are relatable to 

specific geologic terranes, and fractionation of the Sr isotopes 

is generally negligible (McNutt, 2000). The current amount of 

Sr in the environment is the sum of primordial Sr plus any 87Sr 

resulting from radioactive decay of 87Rb (with a half-life of 

4.88 × 1010 years).

Atmospheric deposition of Sr is generally quite low 

and, compared to dissolution of minerals, generally is 

not a significant source of Sr in water (Graustein, 1989). 

Consequently, Sr in water primarily is derived from 

water-rock interaction between groundwater and the geologic 

terranes of the source areas and matrix of an aquifer. An 

anthropogenic source of strontium occurs at the INL, however, 

where 90Sr was discharged to the subsurface at some INL 

facilities (table 7) and a plume of elevated 90Sr activities 

is present in groundwater downgradient of the INTEC 

(Bartholomay, Tucker, and others, 2000; Davis and others, 

2013). Strontium-90 decays to daughter products yttrium-90 

and zircon-90 (stable daughter) and thus has no effect on the 

87Sr/86Sr in groundwater at the INL.

Strontium and rubidium (Rb) may substitute for Ca 

and K, respectively, in minerals. Calcium is abundant in 

many minerals in the study area, such as carbonate (calcite, 

aragonite, and dolomite), evaporite (gypsum and anhydrite), 

and silicate (plagioclase, amphiboles, pyroxenes, micas, and 

clays) minerals, so Sr should be abundant in the study area, 

whereas potassium is present only in a few silicate (potassium 

feldspar, micas, and clays) and evaporite (sylvite) minerals in 

the study area, so Rb should not be abundant in the study area. 

The 87Sr/86Sr value of a mineral reflects the relative abundance 

of Sr and Rb in the mineral and the age of the mineral. For 

instance, if Sr is abundant in a mineral and Rb is not, then the 

87Sr/86Sr value of that mineral will change only slightly over 

time. Conversely, if Rb is abundant in a mineral and Sr is not, 

then the 87Sr/86Sr value of that mineral will increase through 

time due to decay of 87Rb to 87Sr.

Because Ca is abundant in many minerals in the study 

area, and K is not, Sr typically is more abundant than Rb 

in most of the rock types in the study area, although Rb is 

generally more abundant than Sr in sandstone and rhyolite. For 

example, average concentrations (in parts per million) typical 

for rock types in the study area are 610 and 3 for carbonate 

rocks, 300 and 140 for shale, 465 and 30 for basalt, and 20 and 

60 for sandstone for Sr and Rb, respectively (Faure, 1986). 

Strontium and Rb concentrations range from about 50 to 

1,000 and 50 to 500 for dacite and 600 to 1,200 and 10 to 

100 for andesite, respectively (Hedge, 1966). The Sr and Rb 

concentrations measured from 123 basalt core samples (from 

7 coreholes) from the ESRP at the INL ranged from 176 to 

392 and 1.0 to 34 and had mean concentrations of 281 and 

10.7, respectively (Knobel and others, 1995; Reed and others, 

1997). Concentrations measured in rhyolitic tuffs of the Heise 

volcanic field ranged from 22 to 58 for Sr and 220 to 240 for 

Rb (Morgan and others, 1984).

Typical 87Sr/86Sr values of various types of geologic 

terranes are 0.7030 for young, mantle-derived, volcanic 

rocks, 0.7068–0.7092 for marine carbonate rocks, and as 

much as 0.7500 or more for old (>109 years) igneous or 

metamorphic rocks (Graustein, 1989). The 87Sr/86Sr values of 

various types of volcanic terranes at and near the study area 

were 0.7056–0.7080 (mean of 0.7069) for Cenozoic olivine 

basalts on the ESRP, 0.7110–0.7134 for silicic volcanic rocks 

on the ESRP, and 0.7061–0.7085 for Cenozoic basalts from 

Yellowstone National Park and vicinity (Leeman and Manton, 

1971; Graham and others, 2009).

Uranium

The uranium isotope ratio, 234U/238U, can be used in 

groundwater studies to identify groundwater sources, flow 

directions, mixing, and the age of old (tens to hundreds of 

thousands of years; Clark and Fritz, 1997) groundwater 

because U is readily soluble in oxic groundwater, has 

natural variations in groundwater, and the isotopes have 

long half-lives (Roback and others, 2001). Uranium-234 

is a daughter product of the 238U decay series, where 238U 

undergoes α-decay (with a half-life of 4.47 × 109 years) to 

thorium-234 (234Th), and 234U is produced from 234Th by two 

short-lived beta decay events. Uranium-234 is also radioactive 

(with a half-life of 2.48 × 105 years) and eventually decays 

to the stable isotope lead-206 after numerous intermediate 

daughter steps (Clark and Fritz, 1997; Osmond and Cowart, 

2000). In rocks sufficiently old (approximately 106 years) the 

parent and daughter isotopes of the 238U decay series will reach 

secular equilibrium (that is, the activity of the parent isotope 

is identical to its daughters), with an activity ratio for 234U/238U 

of 1 (Luo and others, 2000).

The activity ratio of 234U/238U in groundwater usually 

is greater than 1 because the mobility of 234U is enhanced by 

physical factors associated with α-decay recoil. Alpha‐recoil 

acts to increase the 234U activity in groundwater because 

α-decay of 238U displaces 234Th about 20 nanometers in 

the mineral or rock, resulting in microfracturing of the 

mineral lattice and, in some cases, ejection of 234Th into the 

groundwater solution (Osmond and Cowart, 2000). The 

physical damage to the mineral lattice from the decay of 238U 

also may allow 234Th or 234U to preferentially etch, leach, 

or dissolve from the rock relative to 238U. These physical 

processes cause the 234U/238U ratio in groundwater to increase 

with increasing length of time that the groundwater is in 

contact with geologic materials (although very long contact 

times may cause the ratio to decrease to secular equilibrium as 

mineral sites with leachable 234U become exhausted).
40 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Uranium is present in most rocks in small concentrations, 

and generally will be more abundant in crystalline or felsic 

rocks than in sedimentary or mafic rocks (Osmond and 

Cowart, 2000). Typical average uranium concentrations (in 

parts per million) for rock types in the study area were 1.9 for 

carbonate rocks, 1.4 for sandstone, 3.2 for shale, and 0.43 for 

basalt (Faure, 1986). In the ESRP basalt aquifer at the INL, 

uranium concentrations measured from 95 basalt core samples 

(from 5 coreholes) ranged from 0.02 to 2.4 ppm with a mean 

concentration of 0.7 ppm (Knobel and others, 1995; Reed 

and others, 1997). Due to the larger uranium concentration 

and solubility of carbonate rocks relative to basalt, uranium 

concentrations and 234U/238U ratios in groundwater that flows 

from carbonate aquifers north of the INL into the ESRP 

basalt aquifer are likely to persist in the basalt aquifer for a 

considerable time unless the ratios are modified by mixing 

with surface water or other groundwater.

The activity ratio of 234U/238U in groundwater at the INL 

also may be influenced by anthropogenic sources of uranium. 

Uranium isotopes were discharged to the subsurface at some 

INL facilities (table 8), and anthropogenic uranium was 

present in groundwater downgradient of the INTEC (Beasley 

and others, 1998). Groundwater samples within or near the 

contaminant plume extending downgradient from the INTEC, 

and from which 234U/238U ratios were collected and measured 

(table 16), were examined for the presence of anthropogenic 

and non-natural uranium isotopes, but no anthropogenic or 

non-natural uranium isotopes were detected in the samples 

(Roback and others, 2001).

Environmental Tracers

Tritium

Large quantities of 3H, the radioactive isotope 

of hydrogen, were introduced into the atmosphere by 

thermonuclear bomb testing in the 1950s and 1960s (Solomon 

and Cook, 2000). Because 3H is readily incorporated into 

water molecules in the atmosphere and is rapidly removed 

from the atmosphere in meteoric precipitation, the large 

peak and subsequent decrease of 3

H concentrations in the 

atmosphere make 3H a useful tracer for determining the age 

of water. Because the half-life of 3H is only 12.34 years, 3H is 

currently most useful for qualitatively estimating the residence 

time of water as older or as younger than the year (1952) when 

thermonuclear bomb testing in the atmosphere began.

Approximately 31,620 curies (Ci) of 3H was discharged to 

the subsurface at the INTEC and ATRC between 1952 and 1998 

(Bartholomay, Tucker, and others, 2000), with approximately 

21,135 Ci of the 3H discharged at the INTEC (Davis, 2006; 

Davis and others, 2013). This has resulted in elevated activities 

of 3H, and a 3H plume, in groundwater downgradient of the 

ATRC and INTEC (Bartholomay, Tucker, and others, 2000; 

Davis and others, 2013). The 3H derived from wastewater 

cannot be used to estimate the age of groundwater at the INL, 

although with 3H-3He age dating wastewater 3H may be used 

to estimate the age of wastewater disposal and average linear 

groundwater velocities (Busenberg and others, 2001; Ackerman 

and others, 2006).

The age of groundwater was qualitatively estimated, 

by plotting the 3H activity of a water sample and the date of 

sample collection, as old groundwater, young groundwater, 

a mixture of young and old groundwater, or groundwater 

containing 3H from wastewater (fig. 13). Old groundwater 

was defined as a 3H activity equal to or less than the line on 

figure 13A representing the radioactive decay (the equation for 

radioactive decay of 3H is presented in appendix 2, eq. 2-12) 

of 3H in water recharged in 1952, using a pre-bomb 1952 3H 

activity in precipitation of 48 pCi/L (Morris and others, 1963). 

Young groundwater (and surface water) was defined as a 3H 

activity within an area approximated by a line on figure 13A

representing the decay of 3H in groundwater recharged from 

precipitation during the mid-1960s (upper bound) and the 

activity of 3H in precipitation at the INL17 from the late 1980s 

through 2012 (lower bound). Groundwater plotting between 

the lower bound for young water and the line representing 

the decay of 3H in precipitation recharge from 1952 likely 

is a mixture of young and old groundwater, although this 

groundwater also could be young recharge from the mid-1950s. 

Groundwater plotting above the upper bound for young water 

probably is contaminated with 3H from discharge of wastewater. 

Groundwater containing 3H from wastewater also may plot 

between the upper bound for young water and the activity of 3H 

in precipitation at the INL, so water plotting in this area may be 

either young groundwater or groundwater contaminated with 3H 

from wastewater.

The definitions of young and old groundwater do not 

preclude that these waters also could be mixtures of young and 

old groundwater. For example, groundwater that was a mixture 

of 50 percent 1970 recharge (tritium activity of approximately 

1,000 pCi/L) with 50 percent old groundwater (with zero tritium 

activity) would have a tritium activity of about 125 pCi/L in 

the mid-1990s and would appear to be young groundwater. 

17The estimated monthly activity of 3

H in precipitation at the INL was calculated for 1953 through 1983 from data in Michel (1989), for 1984 through 2001 

from data provided by R.L. Michel (U.S. Geological Survey, written commun., 2012), and was estimated for 2002 through 2012 from a regression (R2 = 0.91; 

appendix 2, eq. 2-13) of calculated monthly 3H activities from data provided by R.L. Michel with measured 3H activities in precipitation measured at Vienna 

(International Atomic Energy Agency/World Meteorological Organization, 2015) for 1990 through 2001.
Sources of Chemical and Isotopic Constituents 41

tac18-1192_fig13a

0.1

1.0

10.0

100.0

1,000.0

10,000.0

100,000.0

1952 1962 1972 1982 1992 2002 2012

Tritium, in picocuries per liter (pCi/L)

Date of sample collection

Old groundwater

Young water

Mixture of young

and old water

Groundwater

containing tritium

from wastewater

105

108 120

22

Atmospheric

bomb testing

begins

124

109

BC

9

11

ML 25 PSTF Test

86

5 BFW 29

ANP 6

FS2

15

23 32

18

6

ANP 9 ML 29 NN1 83 7

26 117,31

82

112

CFA 1

CFA 2 113

116

36 115

M3S

M7S 104

ML 31

ML 6

Site 9

1 101 27,

Site 14

P&W2

Wagoner AC

14,98

110A 100

ML 57

ML 17

ML 5

CC

ML 59

ML 58

ML 12

NRF 11

NRF 10

ML 55

ML 24,ML 30

NRF 9

107

ACW4

65 TAN Disp 57

85

20 24

TDD2

RWMC Prod

90 87 TDD1

Sorenson, Oar

LLR

Site 19

AT1,19,103 Area II,LR1,2

Middle 2051

135

134 Site 17 ANP 8

Site name=Deep groundwater Owen

Lambert

Coates,Wheeler

Hill

MSR 12

Mays

RF

Tritium uncertainties (1σ) and approximations 

Most groundwater from the ESRP aquifer: ≤2.3 pCi/L or ≤10 percent

Some groundwater contaminated with tritium: >10 percent

Tributary groundwater, BC, and LLR: ≤13.4 pCi/L

If a tritium value plus the uncertainty was ≤0.1 pCi/L, the value was

shown as 0.1 pCi/L.

A

Decay of tritium in post-bomb precipitation recharge

Decay of tritium in pre-bomb precipitation recharge from 1952

Backwards projected decay of tritium in USGS 22

Estimated monthly activity of

tritium in precipitation at the

Idaho National Laboratory

B

10

100

1994 1995 1996 1997 1998 1999 2000 2001

Tritium, in picocuries per liter (pCi/L)

Date of sample collection

Young water

Mixture of young

and old water

Estimated monthly activity of 

tritium in precipitation at the 

Idaho National Laboratory

Groundwater containing

tritium from wastewater ACW4

BC

99

14

Harrell

5

29 BFW

FS2

17

11

2

102

ML 22

125

NRF 8 Muffett

8 INEL-1 WS

Wagoner

AC

98

110A

100

ML 19

NRF 12

NRF 13

NPR Test

107

NRF 6

KGS

97

12

Sorenson

RR

WR, LLR

Site 19

AT1 Area II ,LR1

Nicholson

Site 4

Pancheri

19, 103

LLR

9

Oar BLR Fulton

MSR

WGS

Hill

Coates, Wheeler

Tritium uncertainties (1σ)

Most groundwater from the ESRP aquifer: ≤2.3 pCi/L or <10 percent

Some groundwater contaminated with tritium: >10 percent

Tributary groundwater, BC, and LLR: ≤13.4 pCi/L

Figure 13. Activity of tritium in surface water and groundwater, the estimated monthly activity of tritium in precipitation, 

decay curves representing the possible evolution of tritium activities in pre-bomb and post-bomb recharge from precipitation, 

and areas on the graph representing old groundwater, young water, mixtures of young and old water, and wastewater, Idaho 

National Laboratory and vicinity, eastern Idaho. (A) Tritium activities of water samples collected between 1952 and 2012. 

(B) Water samples collected between 1994 and 2001 with tritium activities between 10 and 100 picocuries per liter.
42 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Similarly, groundwater that was a mixture of 5 percent 1983 

recharge (tritium activity of approximately 100 pCi/L) with 

95 percent old groundwater (with zero tritium activity) would 

have a tritium activity of about 2.5 pCi/L in the mid-1990s and 

would appear to be old groundwater.

Terrigenic Helium

Terrigenic helium (Heterr) consists of the helium in 

groundwater that was derived from the crust and mantle 

(Heterr = Hecrust + Hemantle) and is represented as a percentage 

of the total amount of helium in the groundwater. The Heterr

in a groundwater sample can be calculated by rearranging 

the mass balance equation for helium and solving for Heterr. 

The rearranged mass balance equation is (Busenberg and 

others, 2001)

Heterr = Hetot – Heeq + Heair + Hetrit, (1)

where

Heterr is the terrigenic helium,

Hetot is the measured helium in the water sample,

Heeq is the helium in solution in equilibrium with 

air,

Heair is the helium in solution derived from excess 

air in solution, and

Hetrit is the helium in solution produced by 

radioactive decay of 3H (tritiogenic 

helium).

The Heterr equation can be used to estimate the recharge 

source and relative age of groundwater in the ESRP aquifer at 

the INL to indicate whether the groundwater consists of recent 

recharge; regional, and presumably older, groundwater; 

or contains some old, deep groundwater with some mantle 

helium. Recent recharge refers to groundwater that has been 

in contact with air or the unsaturated-zone atmosphere within 

the past several hundred years and has not mixed with regional 

groundwater, and recent recharge generally has a Heterr of 

about 0–10 percent (Busenberg and others, 2001). Regional 

groundwater, which has been in contact with the aquifer 

matrix for a longer period (several hundred years or more), 

contains a significant amount of crustal helium. Busenberg 

and others (2001) observed that regional groundwater at and 

near the INL, and unaffected by recent recharge, generally 

has a Heterr of about 80–90 percent and that thermal springs in 

the area, which contain mantle helium, had a Heterr exceeding 

95 percent.

For this report, however, ranges of Heterr values indicating 

specific sources for helium and water were reinterpreted 

for the ESRP aquifer based on how helium concentrations 

and ratios evolve (fig. 12) and Heterr values compared to 3H 

activities (fig. 14). The ranges of 3H activities indicated young 

groundwater (typically 30–75 pCi/L for groundwater at the 

INL), old groundwater (typically <4 pCi/L), or a mixture of 

young and old groundwater (4–30 pCi/L). The Heterr values 

equal to or less than 10 percent were interpreted to represent 

recent recharge containing helium in equilibrium with air, 

between 10 and 50 percent represent crustal helium in regional 

or tributary groundwater that has mixed with a large amount 

of recent recharge, 50–80 percent represent crustal helium 

in regional or tributary groundwater that has mixed with a 

small amount of recent recharge, and that exceed 80 percent 

represent mantle helium either in geothermal water or in 

regional or tributary groundwater containing some geothermal 

water (figs. 12 and 14). The Heterr values that exceeded 

80 percent were interpreted to represent some contribution 

from mantle helium because (1) Heterr values of 88–89 percent 

were present in groundwater from ML 25 and USGS 27, and 

these wells were interpreted to contain geothermal water (with 

mantle helium) based on geochemical modeling (Rattray, 

2015) or a large Rs/Ra ratio (9.70; fig. 12), respectively; and 

(2) Heterr values of 82–91 percent (and helium concentrations 

exceeding 20 × 10-8 cm3 STP/g) were present in either deep 

groundwater (Site 14, USGS 15) or in groundwater (Site 14, 

USGS 18, USGS 26, USGS 31) immediately downgradient 

of sites (ML 27, ML 29, USGS 7, USGS 27) containing 

geothermal water. Identification of sites containing geothermal 

water was based on geochemical modeling (ML 27 and 

ML 29; Rattray, 2015), a large Heterr value (97 percent) and 

helium concentration (149 × 10-8 cm3 STP/g) (USGS 7), and a 

large Rs/Ra ratio (USGS 27).

In combination with tritium activities, Heterr also may be 

used to determine the mechanism of recharge (Busenberg and 

others, 2001, p. 70–72). Rapid, focused recharge or recharge 

through a thin unsaturated zone has small Heterr concentrations 

(<10 percent) and measurable tritium activities, while slow, 

diffuse recharge through a thick unsaturated zone also has 

small Heterr concentrations (<10 percent) but little or no 

tritium (fig. 14).

Tritium/Helium-3, Chlorofluorocarbons, and 

Sulfur Hexafluoride

The environmental tracers 3H/3He, CFCs, and SF6 were 

used to estimate the age of the young fraction of groundwater 

in the ESRP aquifer at the INL. These tracers were useful for 

estimating the age of young groundwater that recharged since 

about 1940–70 (Busenberg and others, 2001).

The 3H/3He age-dating method is based on the fact that 

the daughter product from radioactive decay of 3H is 3He. 

This leads to an ingrowth of 3He with time in groundwater 

containing 3H (see ingrowth equation in appendix 2, eq. 2-14). 
Sources of Chemical and Isotopic Constituents 43

tac18-1192_fig14

0.1

1.0

10.0

100.0

1,000.0

0 20 40 60 80 100

Tritium, in picocuries per liter

Terrigenic helium, in percent

Old groundwater

Older groundwater

Young groundwater

Younger groundwater Mixture of young and old groundwater

NN 1

ANP 6 PSTF Test

Site 19

BFW

98

22

9

32

86 27 Site 14

17

11

125

Site 9

Area II

29

23

5

15

18

31 26 7

ANP 9

6

102

Site 4 99,FS2 8

97

NPR Test

12

14

103

AC

1

110A

100 AT1

19

107

LR1 2

117

Site 17

Slow,

diffuse

recharge 

Rapid,

focused

recharge 

101

P&W 2

ML 22

ML 57

ML 25

ML 19

Contains much crustal helium;

tributary water and (or) regional

groundwater mixed with a small

amount of recent recharge 

Contains mantle helium;

geothermal water or

groundwater with a

geothermal input

Contains some crustal helium; tributary water

and (or) regional groundwater mixed with a

large amount of recent recharge 

Helium in

equilibrium

with air;

recent

recharge

Birch Creek valley groundwater

Regional groundwater

Geothermal water or groundwater with a geothermal input

Deep groundwater

North INL Area

Northeast INL Area

Southeast INL Area

Central INL Area

Northwest INL Area

Southwest INL Area

EXPLANATION

Figure 14. Activity of tritium and percent terrigenic helium, ranges of tritium activities that indicate the qualitative 

age of groundwater, and ranges of terrigenic helium that were interpreted to represent specific sources of helium 

and water, Idaho National Laboratory and vicinity, eastern Idaho.
44 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

By combining the equations for radioactive decay of 3H 

and ingrowth of 3He, the age of the groundwater may be 

determined from the measured activities of 3H and 3He (Clark 

and Fritz, 1997; Solomon and Cook, 2000).

Complications to age dating with 3H-3He arise due to 

the various sources of 3H and 3He (sources of 3H and 3He 

are discussed in the sections, “Tritium” and “Helium”). 

Determining the amount of ingrown 3He requires that all other 

sources of 3He be subtracted from the measured concentration 

of 3He. This requires solving the 3He mass balance equation 

for ingrown, or tritiogenic, 3He. The rearranged mass balance 

equation is (Busenberg and others, 2001)

3

Hetrit = 3Hetotal – 3Heeq – 3Heair – 3Heman – 3Herad, (2)

where 3

Hetrit is the ingrown helium-3 produced by 

radioactive decay of tritium, 3

Hetotal is the measured helium-3 in the groundwater 

sample, 3

Heeq is the helium-3 in solution in equilibrium with 

air, 3

Heair is the helium-3 in solution derived from 

excess air in solution, 3

Heman is the helium-3 introduced from mantle fluids, 

and 3

Herad is the helium-3 produced by radioactive decay 

of uranium, thorium, and lithium in crustal 

rocks.

At the INL, some groundwater could not be dated 

with 3H/3He due to large amounts of 3Heman, 3Herad, and 

contamination of groundwater with 3H from industrial 

wastewater disposal. Where wastewater 3H was present, the 

travel time of the water from the disposal site was determined, 

not the age of the young fraction of groundwater (Busenberg 

and others, 2001).

CFCs are halogenated gases that initially were developed 

in the 1930s for use in refrigeration. They are volatile 

compounds, so they quickly entered the atmosphere and 

then the hydrosphere. CFCs are a useful age-dating tool of 

young groundwater because the atmosphere was free of these 

compounds until the 1930s, release of CFCs to the atmosphere 

has caused atmospheric mixing ratios to increase from 1940 

to 1990, the atmospheric mixing ratios of CFCs are known or 

have been reconstructed, the Henry’s Law solubilities of CFCs 

in water are known, and accurate measurements can be made 

from water samples with low CFC concentrations (Plummer 

and Busenberg, 2000). The mixing ratios of CFC-11, CFC-12, 

and CFC-113 in the atmosphere increased at different rates, 

so groundwater ages may be estimated from individual 

CFC mixing ratios or from ratios of two CFC mixing ratios 

(Busenberg and others, 2001).

The calculated groundwater age from CFC concentrations 

refers to the time elapsed since the recharge water was 

isolated from the unsaturated-zone atmosphere and assumes 

that water recharging an aquifer was in equilibrium with the 

unsaturated-zone atmosphere (Busenberg and Plummer, 2000; 

Plummer and Busenberg, 2000). The term “model age” is used 

in reference to CFC ages because there are numerous physical 

and chemical processes that can influence the calculated age. 

Some physical and chemical processes that may affect the 

calculated model ages of groundwater include the estimated 

recharge temperature at the air-groundwater interface, the 

elevation at which recharge occurred, the amount of excess 

air in the groundwater, the method of recharge through the 

unsaturated zone, gas transport processes in the unsaturated 

zone, mixing of water, hydrodynamic dispersion, degradation 

of CFCs, and CFC contamination from local anthropogenic 

sources (Plummer and Busenberg, 2000; Busenberg and 

others, 2001).

In calculating the model age of the young fraction of 

groundwater at the INL, Busenberg and others (2001) used 

several simplifying assumptions and noble gas concentrations 

in groundwater to estimate recharge temperature and elevation, 

excess air, and method of recharge. They used conceptual 

models to define some other processes. For instance, recharge 

was modeled through the unsaturated zone as occurring either 

slowly or rapidly, and groundwater in the aquifer was modeled 

as either unmixed or as a mixture of young and old water. If 

mixing was modeled, then the fraction of young groundwater 

in the sample needed to be estimated. These estimates were 

made based on the mixing ratio of a CFC compound in air at 

the time of recharge and the concentration of the same CFC in 

the water sample, chemical and isotopic concentrations in the 

water sample, or geochemical modeling.

The application of SF6 for age dating young groundwater 

is similar to that for CFCs. SF6 is a stable, volatile gas that 

began to be produced for industrial purposes in the 1950s. 

Substantial production began in the 1960s, atmospheric 

mixing ratios rose rapidly beginning in the late 1970s, and age 

dating with SF6 is possible back to about 1970 (Busenberg and 

Plummer, 2000).

Like CFCs, the model age of groundwater calculated 

from SF6 concentrations refers to the time elapsed since 

the recharge water was isolated from the unsaturated-zone 

atmosphere and assumes that the water recharging an aquifer 

is in equilibrium with the unsaturated-zone atmosphere. Most 

of the same physical and chemical processes that affect CFC 

concentrations also affect SF6, although SF6 does not seem 

to degrade and is less likely to be from local contamination. 

There is a natural source for SF6 in groundwater, because 

many igneous rocks contain low concentrations of SF6. 

Water can be dated with SF6 when the igneous component of 

SF6 is small relative to other sources of SF6 (Busenberg and 

Plummer, 2000; Busenberg and others, 2001).
Geochemistry of Surface Water and Groundwater 45

Busenberg and others (2001) calculated the model age 

of groundwater from SF6 concentrations using the same 

assumptions and models described for modeling CFCs. 

Procedures to correct for natural, or igneous, SF6 have not 

been developed, so no correction was made to model ages 

calculated from SF6 concentrations. Some groundwater 

samples from the INL could not be dated with SF6 because 

they had SF6 concentrations larger than modern air-water 

equilibrium, indicating a significant source of SF6 from 

igneous rocks (Busenberg and others, 2001).

The estimated model ages of young groundwater from a 

site, based on methods using 3H/3He, individual CFCs and SF6, 

and ratios of CFCs and SF6, varied considerably (Busenberg 

and others, 2001). Difficulties in the age dating methods may 

be caused by variability in the analytical data, the complexity 

of estimating groundwater ages in groundwater at the INL 

with environmental tracers (Busenberg and others, 2001), 

and using models to calculate the age of young groundwater 

that are dependent on an assumption of binary mixing. Young 

groundwater at the INL generally consists of numerous 

episodic surface-water-recharge events that have occurred 

since the 1940s, so much of the groundwater at the INL 

may be a mixture of more than two sources of water. Due to 

these difficulties in estimating the age of young groundwater, 

Busenberg and others (2001) stated that the results should be 

used with caution. However, a conservative interpretation of 

data from Busenberg and others (2001) is that water samples 

containing CFCs and SF6 contain some young groundwater.

Carbon-14

Carbon-14 can be used for dating groundwater as old as 

50,000 years, identifying sources of recharge, and evaluating 

groundwater mixing because 14C undergoes radioactive 

decay with a relatively long half-life (5,730 years), carbon is 

ubiquitous in groundwater, and there are numerous sources 

and sinks of carbon (Clark and Fritz, 1997). Carbon-14 is 

naturally produced in the atmosphere, but also was introduced 

into the atmosphere by thermonuclear bomb testing in the 

1950s and 1960s. Carbon-14 in the atmosphere also has 

been diluted during the industrial age by combustion of 

fossil fuel. In the atmosphere, 14C quickly oxidizes to CO2

and subsequently assimilates into the biosphere (through 

photosynthesis) and hydrosphere (through exchange reactions 

with meteoric waters and the ocean; Clark and Fritz, 1997; 

Kalin, 2000).

Carbon-14 enters groundwater through gas exchange of 

CO2 with the atmosphere, soil zone, or unsaturated zone and 

dissolution of carbonate minerals containing geologically 

young carbon (Kalin, 2000). Marine carbonates on continents 

are geologically old, so they no longer contain any 14C (that 

is, “dead” carbon). Carbon, and therefore 14C, is present in 

groundwater as dissolved organic (DOC) or inorganic (DIC) 

carbon. Concentrations of DIC are much larger in groundwater 

at the INL than concentrations of DOC, and measurements of 

14C in groundwater from the INL are made from DIC.

The modern activity of 14C18 is reported relative to an 

international “modern carbon” standard, based on the 1950 

concentration of 14C in the atmosphere, in units of percent 

modern carbon (pmC) (Clark and Fritz, 1997). Since the 

modern activity is referenced to the 1950 activity of 14C in the 

atmosphere (that is, the 1950 14C activity in the atmosphere 

= 100 pmC), values of pmC greater than 100 indicate a 

post-1950 age of groundwater and pmC values less than 

100 indicate a pre-1950 age of groundwater (Kalin, 2000). 

However, sources of “dead” carbon may reduce the activity 

of 14C in groundwater, so the age of groundwater with pmC 

values less than 100 is ambiguous.

Quantitative determination of the radiocarbon ages 

of groundwater can be calculated from the equation for 

radioactive decay (analogous to the equation for radioactive 

decay of 3H in appendix 2, eq. 2-12). However, determining 

the initial activity of 14C in groundwater is complicated from 

the varying activities of 14C in the atmosphere through time, 

fractionation of carbon during phase transformations, and 

the potentially numerous sources of carbon with different 

14C activities. Corrections for these processes are complex, 

but are routinely performed (Clark and Fritz, 1997; Kalin, 

2000). Radiocarbon ages were not calculated for this report 

because most of the groundwater in the ESRP aquifer at the 

INL contains measurable tritium and is therefore too young to 

allow for reliable determination of radiocarbon ages (Plummer 

and others, 1993).

Geochemistry of Surface Water and 

Groundwater

The geochemistry of groundwater at the INL was 

influenced by different sources of recharge, physical and 

chemical processes occurring in the ESRP aquifer, and 

temporal variability. The geochemistry of different sources of 

recharge, and the physical and chemical processes occurring 

in the ESRP aquifer, was determined by comparing the 

chemistry of each water group and relating differences in 

chemistry to differences in land use, geology, and hydrology. 

The geochemistry of some groundwater at the INL undergoes 

temporal variability, and understanding the causes of these 

temporal changes was essential for fully understanding the 

influence of different sources of recharge, and the physical 

and chemical processes occurring in the ESRP aquifer, on 

groundwater geochemistry at the INL.

18Modern in this context refers to groundwater recharged after 1950.
46 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Sources of recharge with the most potential to influence 

the geochemistry of groundwater at the INL included 

(1) concentrated sources of dilute recharge, such as infiltration 

of the BLR through the INL spreading areas and the BLR 

channel, sinks, and playas (Bennett, 1990; Bartholomay and 

others, 2012); (2) the largest sources of recharge, such as 

underflow of regional groundwater from the Mud Lake area 

east of the INL and underflow of tributary valley groundwater 

from the LLR and BC valleys north of the INL (table 1); 

and (3) sources of recharge with large concentrations of 

chemical or radiochemical constituents, such as return flows 

of irrigation water in the Mud Lake area and the LLR valley 

that contain agricultural wastes (Swanson and others, 2002; 

Rattray, 2015), upward flow of brackish geothermal water 

(Mann, 1986; Rattray, 2015), and industrial wastewater 

discharge at the INL (Davis and others, 2013).

Precipitation, industrial wastewater discharge, and 

geothermal water provided recharge to the ESRP aquifer 

near the INL in small amounts at localized areas (table 1) 

(Bartholomay, Tucker, and others, 2000; Ackerman and 

others, 2006; Rattray, 2015). Precipitation was chemically 

dilute and recharge of precipitation would only dilute nearby 

groundwater. In contrast, relatively small amounts of recharge 

of industrial wastewater and geothermal water (table 1), 

which contained large concentrations of some chemical 

and radiochemical constituents (tables 13–14 and 17), 

mixed with comparatively dilute groundwater in the ESRP 

aquifer, thereby constraining these sources of chemical or 

radiochemical constituents to a local influence on groundwater 

geochemistry that diminishes noticeably with distance from 

the point source (Davis and others, 2013). The chemistry 

of recharge from irrigation water and industrial wastewater 

was not available, so the effect these recharge sources had 

on groundwater chemistry was evaluated indirectly from the 

chemistry of affected groundwater. For example, the effect 

on groundwater geochemistry from irrigation return flows 

and wastewater discharge was indirectly evaluated from the 

chemistry of groundwater in irrigated areas and contaminated 

groundwater, respectively.

Interpretations about sources of recharge for 

groundwater at the INL primarily were made from the 

statistical and spatial distribution of concentrations or values 

of chemical and isotopic constituents. These distributions were 

presented in box-and-whisker plots (herein called boxplots) 

(figs. 27A–LL [at back of report]) and maps (figs. 28A–DD

[at back of report]). Other graphical methods used to make 

interpretations about sources of water and groundwater at 

the INL, such as trilinear (fig. 10A) and δ2H-δ18O diagrams 

(fig. 11), were described in the section, “Sources of Chemical 

and Isotopic Constituents.”

Boxplots were used to compare and contrast the 

chemistry of different sources of water and groundwater from 

spatially defined areas at the INL (fig. 9). The box height 

represents the variation or range of the inner two quartiles 

of data (second and third quartiles, also inner quartile range 

[IQR]) and is divided into two halves by the median. The 

relative heights of the box halves indicate the skewness 

of the inner quartile data, the lines (or whiskers) show the 

minimum and maximum data points (excluding outliers) and 

indicate variability of the outer two quartiles (1st and 4th 

quartiles) of data, and individual points represent outlier data 

(Helsel and Hirsch, 2002). Outliers consist of data points 

that exceed 1.5 times the IQR. Chemistry data that were 

censored (<, less than; >, greater than, >>, much greater 

than), included remarks (E, estimated; ?, uncertain), ranges 

of values (10–20 years before the sampling date), or that 

included uncertainty estimates (value ± uncertainty) were 

included in boxplots using the censored value (<1 μg/L was 

included as 1 μg/L), the value without the remark (E4.7 μg/L 

was included as 4.7 μg/L), the midpoint of the range of 

values (10–20 years before the sampling date was included as 

15 years before the sampling date), and the value without the 

uncertainty (22.4 ± 12.8 pCi/L was included as 22.4 pCi/L). 

Thirteen tritium activities with uncertainties that equaled 

or exceeded the absolute value of the reported activity, and 

with uncertainties that exceeded 9.5 pCi/L (for example, 

12.8 ± 12.8 pCi/L), were excluded from the boxplot for tritium 

activities (fig. 27II). Estimated ages of the young fraction of 

groundwater include a remark, “old,” for USGS 23 (table 17), 

and in the boxplot for the estimated age of the young fraction 

of groundwater the remark “old” was set to 55 years before the 

sampling date (fig. 27KK).

Chemical and Isotopic Constituents

Field Parameters

Water temperatures ranged from 6 to 57 °C (table 12). 

Groundwater in the tributary valleys generally had colder 

temperatures than regional groundwater, and the warmest 

groundwater temperatures were in geothermal water 

(fig. 27A). Numerous factors influenced the difference 

in temperatures between tributary valley and regional 

groundwater. For instance, tributary valley groundwater 

originated mainly as snowmelt at high elevations, which 

produced cold groundwater. Regional groundwater, probably 

had longer groundwater residence times than tributary valley 

groundwater (based on tritium activities in figure 28BB), 

was warmed by the large geothermal gradient in the ESRP 

(Blackwell and others, 1992), and may include geothermal 

water that moved vertically upward (Mann, 1986; Rattray, 

2015). These influences on groundwater temperatures 

were apparent at the INL, as recharge from tributary water 

(streams and groundwater) and regional groundwater 

produced temperatures that were colder in groundwater 

in the northwestern part of the INL than the southeastern 

part (fig. 28A).

The pH ranged from nearly neutral (7.1) to slightly 

alkaline (8.6) (table 12). Tributary valley and regional 

groundwater pH values generally were smaller than 

groundwater at the INL, whereas pH values in surface water 
Geochemistry of Surface Water and Groundwater 47

generally were larger (fig. 27B). Most pH in natural (as well 

as deep and contaminated) groundwater ranged from 7.8 to 

8.3, with slightly larger pH values in groundwater from the 

southern parts of the INL (Southeast, Central, and Southwest 

INL Areas) than in the northern parts (North, Northeastern, 

and Northwestern INL Areas). The slightly larger pH in the 

southern parts of the INL may be due to consumption of CO2

from dissolution of silicate minerals in the ESRP aquifer 

(Rattray and Ginsbach, 2014).

Specific conductance ranged from 147 to 1,878 μS/cm 

at 25 °C (table 12). Specific conductance in tributary valley 

and regional groundwater ranged from 180 to 1,100 μS/cm 

at 25 °C, with larger specific conductance in groundwater 

from irrigated areas. Specific conductance values generally 

were less than 400 μS/cm at 25 °C in surface water, deep 

groundwater, and natural groundwater from the North, 

Southeast, Central, and Southwest INL Areas, and more 

than 400 μS/cm at 25 °C in geothermal water, contaminated 

groundwater, and natural groundwater from the Northeast 

and Northwest INL Areas (fig. 27C). The large specific 

conductance values in groundwater from the Northeast and 

Northwest INL Areas were due to irrigation in the upgradient 

Mud Lake and Howe areas (fig. 28B), respectively.

Alkalinity ranged from 71 to 740 mg/L as CaCO3

(table 12). However, except for geothermal water from 

test hole INEL-1 10,300 feet (740 mg/L as CaCO3) and 

irrigation‐influenced regional groundwater from ML 30 

(384 mg/L as CaCO3), alkalinity was less than or equal to 

279 mg/L as CaCO3. Natural groundwater, except from the 

Northwest INL Area, had small alkalinity (84–165 mg/L 

as CaCO3) (fig. 27D). Larger alkalinity concentrations in 

groundwater from the Northwest INL Area may be due to 

irrigation in the upgradient Howe area, where infiltration 

of irrigation water transported soil CO2 downward to 

the alluvial aquifer, and the increased CO2 in the aquifer 

enhanced dissolution of carbonate minerals in the aquifer 

matrix (Rattray, 2015). The smallest alkalinity concentration 

was from USGS 22, which is also from the Northwest INL 

Area. Busenberg and others (2001, p. 90), in evaluating 

the age of the fraction of young groundwater at USGS 22, 

suggested that groundwater at this site represented recent 

infiltration of precipitation. The small alkalinity of this 

groundwater probably was due to the short residence time of 

this groundwater in the ESRP basalt aquifer; therefore, the 

time available for carbonate and silicate reactions to proceed 

was limited.

Dissolved Gases

Dissolved-oxygen concentrations ranged from 0.1 to 

12.2 mg/L (table 12, figs. 27E and 28C). Most surface water 

was saturated with DO (≥8.4 mg/L), most tributary valley, 

regional, deep, contaminated, and natural groundwater was 

either saturated or slightly undersaturated (≥6 mg/L), and 

geothermal water was considerably undersaturated (<6 mg/L) 

or anoxic (INEL-1 10,300 feet; anoxic interpretation was 

based on large iron and small uranium concentrations; 

table 14). Anoxic (<0.5 mg/L) groundwater was measured 

from four other sites (Wildhorse Guard Station, Kaufman 

Guard Station, ML 25, TAN Disposal), and these anoxic 

conditions probably were due to confined aquifers at the 

headwaters of the BLR and BC valleys, mixing of regional 

groundwater with anoxic geothermal water and subsequent 

oxidation-reduction reactions (Rattray, 2015), and oxidation 

of organic compounds discharged in wastewater at TAN 

(U.S. Department of Energy, 2011).

The partial pressure of CO2 ranged from -3.7 to -1.8 (as 

log PCO2) (table 12). The largest partial pressures of CO2

were in geothermal water, tributary valley groundwater, and 

regional groundwater and the smallest partial pressures were 

from surface water and natural groundwater in the southern 

part of the INL (Southeast, Central, and Southwest INL Areas) 

(figs. 27F and 28D). The larger partial pressures of CO2 in 

tributary valley and regional groundwater were from the 

downward transport of soil CO2 associated with natural and 

anthropogenic sources of recharge, and the smaller partial 

pressures of CO2 in groundwater from southern part of the 

INL were from infiltration of the BLR on the ESRP (where 

rapid, focused recharge prevented infiltration recharge from 

equilibrating with soil CO2; Busenberg and others, 2001) and 

consumption of CO2 from dissolution of silicate and carbonate 

minerals in the ESRP aquifer (Rattray, 2015).

Helium concentrations ranged from 4.0 × 10-8 to 

149 × 10-8 cm3 STP/g (table 12). Helium measurements 

from source waters were few in number, but they did 

show that different source waters have distinctive helium 

concentrations. No measurements of helium concentrations 

were made in surface water, but surface water should be 

in equilibrium with air and have a helium concentration 

of about 4.5 × 10-8 cm3 STP/g (Clark and Fritz, 1997). 

Helium concentrations in other source waters ranged 

from 4.1 × 10-8 to 10 × 10-8 cm3 STP/g in tributary valley 

groundwater, 4.8 × 10-8 to 41.8 × 10-8 cm3 STP/g in regional 

groundwater, and was 120 × 10-8 cm3 STP/g in geothermal 

water from ML 57 (fig. 28E). Helium concentrations in deep 

groundwater ranged from 5.5 × 10-8 to 149 × 10-8 cm3 STP/g, 

with the largest concentration, from USGS 7, indicating that 

this groundwater contained either some geothermal water 

or helium from the mantle. Helium concentrations ranged 

from 4.5 × 10-8 to 11.5 × 10-8 cm3 STP/g in contaminated 

groundwater and 4.0 × 10-8 to 32.4 × 10-8 cm3 STP/g in natural 

groundwater. Excluding outliers, helium concentrations in 

contaminated groundwater and natural groundwater from the 

North, Northwest, and Southwest INL Areas were similar 

to concentrations in surface water and tributary valley 

groundwater (fig. 27G), indicating that surface water and 

tributary valley groundwater probably were the sources 

of water to these Areas. Helium concentrations in natural 
48 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

groundwater from the Northeast, Southeast, and Central INL 

Areas that were larger than measured for tributary valley 

groundwater indicate that regional groundwater probably 

was a source of water to these Areas, although four helium 

concentrations greater than 20 × 10-8 cm3 STP/g (USGS 18 in 

the Central INL Area and USGS 26, USGS 27, and USGS 31 

from the Northeast INL Area) also may contain some helium 

from geothermal water or deep groundwater.

Major Ions

Statistical and Spatial Distribution

Concentrations of calcium, magnesium, and bicarbonate 

ranged from 7.3 to 130, 0.5 to 45, and 87 to 900 mg/L 

(table 13), respectively. Most calcium, magnesium, and 

bicarbonate concentrations were larger in tributary valley 

groundwater than in regional groundwater (figs. 27H–27J), 

although irrigation produced some large concentrations of 

these constituents in regional groundwater. Compared to 

natural groundwater, surface water and deep groundwater 

generally had smaller calcium, magnesium, and bicarbonate 

concentrations, contaminated groundwater generally had 

larger concentrations, and geothermal water from INEL-1 

had smaller concentrations of calcium and magnesium and 

larger concentrations of bicarbonate. Concentrations of 

calcium, magnesium, and bicarbonate in natural groundwater 

from the Northwest INL Area extended over a wide range of 

concentrations and had larger concentrations than other natural 

groundwater; these larger concentrations probably were due to 

irrigation in the LLR valley (figs. 28F–H).

Concentrations of sodium, potassium, fluoride, and 

silica ranged from 2.8 to 390, 0.6 to 13.6, less than 0.1 to 13, 

and 5.2 to 62 mg/L, respectively. Concentrations of these 

constituents in water reflect the chemistry of the geologic 

terranes that the water originates in (Olmsted, 1962; Robertson 

and others, 1974; Busenberg and others, 2000; Carkeet and 

others, 2001; Swanson and others, 2002, 2003; Rattray and 

Ginsbach, 2014; Rattray, 2015). Surface water originates, and 

tributary valley groundwater resides, in carbonate terrane, 

whereas regional groundwater and geothermal water from 

INEL-1 reside in silicate terrane that includes basalt and 

rhyolite. Consequently, regional groundwater and geothermal 

water from INEL-1 had larger concentrations of sodium, 

potassium, fluoride, and silica (table 7) than surface water 

or tributary valley groundwater (figs. 27K–N). Irrigation 

also influenced sodium and potassium concentrations, and 

produced larger concentrations of sodium in irrigated areas 

of the LLR valley and larger concentrations of sodium and 

potassium in the Mud Lake area (figs. 28I–J). The larger 

concentrations of sodium, potassium, fluoride, and silica in 

natural groundwater from the Northeast and Southeast INL 

Areas, relative to natural groundwater from the North, Central, 

Northwest, and Southwest INL Areas, indicate that recharge 

primarily was from regional groundwater, and possibly some 

upwelling geothermal water, in the Northeast and Southeast 

INL Areas and from surface water and (or) tributary valley 

groundwater in the North, Central, Northwest, and Southwest 

INL Areas. Deep and contaminated groundwater had sodium, 

potassium, fluoride, and silica concentrations that were similar 

to natural groundwater, although larger concentrations of these 

constituents in deep groundwater from USGS 7 probably were 

due to upwelling geothermal water and larger concentrations 

of sodium in some contaminated groundwater were due to 

wastewater discharge.

Concentrations of chloride and nitrate ranged from 1.0 to 

240 mg/L and less than 0.02 to 8.5 mg/L as N, respectively 

(table 13). Regional groundwater generally had larger 

concentrations of chloride and nitrate than surface water, 

tributary valley groundwater uninfluenced by irrigation, 

geothermal water, and deep groundwater (figs. 27O–P), 

all of which had concentrations of chloride and nitrate that 

were generally less than 20 mg/L and less than 1 mg/L as N, 

respectively. Irrigation or wastewater discharge produced 

larger chloride (>20 mg/L) and (or) nitrate (>1 mg/L as N) 

concentrations in some groundwater from the BLR and LLR 

valleys and most contaminated groundwater (figs. 28M–N). 

In natural groundwater, the generally larger chloride and 

nitrate concentrations in groundwater from the Northeast, 

Southeast, and Northwest INL Areas were due to irrigation, 

whereas the smaller concentrations in groundwater from 

the North, Central, and Southwest INL Areas indicate that 

this groundwater was uninfluenced or minimally influenced 

by irrigation.

Concentrations of sulfate ranged from 1.4 to 200 mg/L 

(table 13). Sulfate concentrations greater than or equal 

to 30 mg/L were measured in LLR valley and regional 

groundwater influenced by irrigation, geothermal water,19

and most contaminated groundwater and concentrations less 

than 30 mg/L were measured in surface water, most tributary 

valley groundwater, regional groundwater uninfluenced by 

irrigation, and deep groundwater (figs. 27Q and 28O). Most 

sulfate concentrations were greater than or equal to 24 mg/L in 

natural groundwater from the North and Northeast INL Areas, 

less than or equal to 26 mg/L in natural groundwater from the 

Southeast, Central, and Southwest INL Areas, and ranged from 

14 to 40.4 mg/L in natural groundwater from the Northwest 

INL Area. The larger concentrations in the Northeast 

and Northwest INL Areas may be due to irrigation in the 

Mud Lake and Howe areas, respectively. However, the larger 

19Sulfur in anoxic groundwater, such as geothermal water from INEL-1 10,300 feet, should be in a reduced state as bisulfide (HS-

) under alkaline conditions 

(Drever, 1997, fig. 7–11). However, the sample was analyzed for sulfate, not bisulfide, because any bisulfide in the sample would have become oxidized during 

collection and storage of the water sample.
Geochemistry of Surface Water and Groundwater 49

concentrations in the North INL Area, where no irrigation 

occurs, indicates that the Beaverhead Mountains may contain 

a greater amount of sulfur-bearing minerals, such as anhydrite 

and gypsum, than the Pioneer, Lost River and Lemhi Ranges.

Hydrochemical Facies

Trilinear diagrams were used to indicate the major ion 

compositions of water samples (fig. 10A). Water samples were 

categorized into hydrochemical facies based on their plotted 

location in the trilinear diagrams, and the hydrochemical 

facies of water samples were plotted on a map to illustrate 

spatial differences in major ion concentrations across the 

INL (fig. 10B).

Surface water and tributary valley groundwater, both 

of which originate in carbonate rocks in the mountains north 

of the INL, were primarily Ca-HCO3 hydrochemical facies, 

and regional groundwater, which resides in silicate rocks 

and was influenced by irrigation, was typically Ca-HCO3 or 

mixed cation-HCO3 hydrochemical facies. However, regional 

groundwater from ML 25 and ML 27 (mixed cation-HCO3 and 

Na-HCO3 hydrochemical facies, respectively) plots between 

geothermal water from INEL-1 (Na-HCO3 hydrochemical 

facies) and most regional groundwater on the cation part of 

figure 10A, consistent with the interpretation that groundwater 

at ML 25 and ML 27 was a mixture of geothermal water and 

regional groundwater (Rattray, 2015).

The hydrochemical facies of contaminated groundwater 

samples was primarily Ca-HCO3, although Ca-mixed anion 

and mixed cation-mixed anion water types also were common. 

A Ca-SO4 water type for groundwater from USGS 65 indicates 

that sulfur was a significant waste constituent at ATRC, and 

a mixed cation-Cl water type at USGS 112 and USGS 113 

indicates that chloride was a significant waste constituent 

at INTEC.

The hydrochemical facies of natural groundwater in 

the northwestern part of the INL was primarily Ca-HCO3, 

and the hydrochemical facies of natural groundwater in 

the southeastern part of the INL was either Ca-HCO3 or 

mixed cation-HCO3 (fig. 10B). This spatial distribution 

of hydrochemical facies reflects the influence of recharge 

from surface water and tributary valley groundwater in the 

northwestern part of the INL and regional groundwater in the 

southeastern part of the INL.

The hydrochemical facies of natural groundwater from 

USGS 22, in the Northwest INL Area, was mixed cation-Cl, 

with chloride and sodium comprising much larger percentages 

of total anions and cations, respectively, than other natural 

groundwater (fig. 10A). USGS 22 is located about 0.37 mi 

northeast of State Highway 26, and the larger amounts of 

chloride and sodium in this groundwater may be due to 

solution of road salt applied to the highway in precipitation 

that subsequently infiltrates to the aquifer. 

Dissolved Metals

Concentrations of aluminum (dissolved and total 

recoverable)20 ranged from less than 1 to 1,400 μg/L (table 14). 

Concentrations generally were less than or equal to 20 μg/L 

in groundwater, although several total recoverable aluminum 

concentrations were greater than or equal to 40 μg/L, and 

concentrations ranged from 1 to 116 μg/L in surface water 

(table 14; fig. 27R). The generally small concentrations of 

aluminum were because of the small solubility of aluminum in 

oxic water (Hem, 1992).

Concentrations of barium ranged from 10 to 342 μg/L 

(table 14). Tributary valley groundwater had slightly 

larger barium concentrations than regional groundwater, 

indicating that barium was probably more abundant in the 

carbonate rocks in the mountains than the silicate rocks in 

the ESRP (fig. 27S). However, the largest (>90 μg/L) barium 

concentrations were in contaminated groundwater, tributary 

valley and regional groundwater that were influenced by 

irrigation, and natural groundwater from the Northwest INL 

Area downstream of irrigated areas in the LLR valley. The 

smallest barium concentrations were in regional and natural 

groundwater not influenced or minimally influenced by 

irrigation (fig. 28P). Barium probably was more abundant in 

irrigated areas due to solution of barium-bearing agricultural 

soil amendments, sediment, and (or) rock as irrigation water 

infiltrated through the unsaturated zone to the aquifer. 

Concentrations of boron ranged from 8 to 900 μg/L 

(table 14). Boron concentrations were largest in geothermal 

water and were larger in regional groundwater than surface 

water or tributary valley groundwater (fig. 27T). As a result, 

boron concentrations increased across the INL in a northwestto-southeast direction (fig. 28Q), with larger concentrations 

in the Northeast and Southeast INL Areas than in the North, 

Central, Northwest, and Southwest INL Areas.

Concentrations of chromium ranged from 0 to 190 μg/L 

(table 14). Chromium concentrations were generally less than 

or equal to 20 μg/L (fig. 27U), and these small concentrations 

were a result of the small abundance of chromium in the 

minerals in the carbonate and silicate rocks of the study area 

(Deer and others, 1983; Morgan and others, 1984; Kuntz 

and others, 1992; Lewis and others, 2012). The largest 

concentration of chromium, in contaminated groundwater 

at USGS 65, was from wastewater discharge from 

ATRC (tables 7–8).

20Concentrations of metals in groundwater from NRF 6, NRF 7, NRF 8, NRF 9, NRF 10, NRF 11, NRF 12, and NRF 13 were for total recoverable metals.
50 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Concentrations of iron ranged from 0 to 1,700 μg/L

(table 14). Iron concentrations in surface water ranged 

from less than 10 to 100 μg/L and most concentrations 

in groundwater were less than 100 μg/L, although some 

concentrations greater than 125 μg/L were measured from 

geothermal, contaminated, and anoxic groundwater (fig. 27V). 

Iron concentrations in natural groundwater generally were 

larger than in tributary valley and regional groundwater, 

probably because of dissolution of iron-bearing minerals in 

the ESRP basalt aquifer (Schramke and others, 1996; Knobel 

and others, 1997; Busenberg and others, 2001; Swanson and 

others, 2003; Rattray and Ginsbach, 2014).

Concentrations of lithium ranged from 1.0 to 280 μg/L21

(table 14). Lithium concentrations generally were less than 

10 μg/L in surface water and tributary valley groundwater 

and greater than 10 μg/L in regional groundwater and 

geothermal water (fig. 27W). These sources of water produced 

lithium concentrations at the INL that generally increased 

in a northwest-to-southeast direction. For example, lithium 

concentrations were less than 10 μg/L in natural groundwater 

from the North, Central, Northwest, and Southwest INL 

Areas and greater than 10 μg/L in natural groundwater from 

the Northeast and Southeast INL Areas (fig. 28R). This 

distribution of lithium concentrations indicates that recharge 

in the Northeast and Southeast INL Areas primarily was from 

regional groundwater, whereas recharge in the North, Central, 

Northwest, and Southwest INL Areas primarily was from 

tributary streams and tributary valley groundwater.

Concentrations of manganese ranged from 0 to 140 μg/L 

(table 14). Most concentrations were less than or equal to 

20 μg/L (fig. 27X), although concentrations in anoxic or 

nearly anoxic (0.7 mg/L DO) groundwater ranged from 18 to 

140 μg/L due to the higher solubility of manganese under 

reduced conditions (Hem, 1992).

Concentrations of strontium ranged from 61 to 

1,000 μg/L (table 14). Strontium concentrations generally 

were smaller in surface water than groundwater (fig. 27Y), 

and strontium concentrations in groundwater generally 

were larger in areas influenced by irrigation or wastewater 

discharge (fig. 28S).

Concentrations of uranium ranged from 0.02 to 3.59 μg/L 

(table 14; fig. 28T). These small concentrations were due 

to the low abundance of uranium in crustal rocks (Emsley, 

1989). Uranium concentrations in groundwater generally 

were greater than 1.0 μg/L, and concentrations greater than 

2.0 μg/L probably were due to longer groundwater residence 

times, irrigation, and (or) wastewater discharge (fig. 27Z). 

Concentrations less than 1.0 μg/L were present in groundwater 

with a short aquifer residence time, such as USGS 22, and due 

to the lower solubility of uranium in anoxic groundwater.

Isotope Ratios

Stable Isotope Ratios of Hydrogen and Oxygen

The δ2H and δ18O values in water samples ranged from 

-143.0 to -120.6 and -18.75 to -14.84 permil, respectively 

(tables 3 and 15). Most of the δ2H and δ18O values plot slightly 

below and approximately parallel to the LMWL for winter, 

indicating that snow, the primary source of meteoric water in 

the study area during winter, was the source of most of the 

water (fig. 11).

The δ2H and δ18O values in surface water and tributary 

valley groundwater extend over a wide range (figs. 27AA–BB) 

because water evaporates from the BLR, BC, and Mud Lake, 

producing large δ2H and δ18O values (fig. 11), and δ2H and 

δ18O values decrease in a southwest-to-northeast direction 

in streams and groundwater from the tributary valleys north 

of the INL (fig. 28U). The directional decrease in δ2H and 

δ18O values may be due to altitude and (or) rainout effects 

in precipitation as air masses travel in a southwest-tonortheast direction over the Lost River and Lemhi Ranges 

(Benjamin and others, 2004). The importance of these effects 

was evaluated by plotting the δ18O values of streams and 

groundwater from the tributary valleys against the elevation of 

the sampling site (fig. 15). If the altitude effect was important, 

the δ18O values in streams and groundwater water from a 

tributary valley would decrease with increasing elevation, 

and if the rainout effect was important, the δ18O values 

would decrease in the direction that the storms travel. Linear 

regression showed that δ18O values in groundwater decreased 

with increased elevation for the BLR valley (mean gradient of 

-0.47‰ δ18O per 1,000-ft increase in elevation; R2 = 0.49) but 

not the LLR and BC valleys, so the altitude effect influenced 

the δ18O values in the BLR valley but not the LLR or BC 

valleys. However, the successive decrease of δ2H and δ18O 

values in water from the BLR, LLR, and BC valleys indicates 

that the rainout effect influenced the δ2H and δ18O values in the 

LLR and BC valleys, probably due to increased precipitation 

as air masses traveled over 12,000-ft high peaks in the Lost 

River and Lemhi Ranges (fig. 28U).

Natural groundwater from the North INL Area had a 

wide range of δ2H and δ18O values (fig. 28U). This large 

range was due to recharge of groundwater from the BC valley 

with small δ2H and δ18O values (ANP 6) and recharge of 

surface water from BC with δ2H and δ18O values that became 

enriched during evaporation in playa 4 (No Name 1, fig. 11). 

In addition, δ2H and δ18O values from PSTF Test were similar 

to values from the BLR (fig. 11), but not BC or groundwater 

from the BC valley, which indicates that groundwater at PSTF 

Test was from infiltration recharge of the BLR at playas 3 and 

(or) 4 (fig. 3B).

21The lithium concentration for INEL-1 10,300 feet was approximated as 280 μg/L, the lithium concentration in geothermal water sampled from INEL-1 from 

the depth interval 3,559–4,878 feet below land surface. This approximation appeared reasonable because of the similarity of temperatures and concentrations of 

major ions and dissolved metals in groundwater from INEL-1 10,300 feet and from the sampling depth interval of 3,559–4,878 feet below land surface (Mann, 

1986).
Geochemistry of Surface Water and Groundwater 51

tac18-1192_fig15

USGS 126b

P&W 2

4,500

5,000

5,500

6,000

6,500

7,000

-19.0 -18.5 -18.0 -17.5 -17.0

Altitude, in feet above National Geodetic Vertical Datum of 1929

Stable isotope ratio of oxygen (δ18O), in permil Vienna Standard Mean Ocean Water (VSMOW)

Wagoner Ranch

Mays

BC at Blue Dome

BC KGS

McKinney

Kaufman GS

Birch Creek

Valley

Wildhorse GS

MSR

Ruby Farms

Harrell

Pancheri

Oar

LLR nr Clyde

Sorenson

Wagoner

LLR nr Howe

Little Lost

River Valley 

BLR near Arco

BLR at Mackay Dam

BLR at Br nr Mackay

ACW4

Nicholson

Owen

Wheeler

Muffett

Lambert

Hill

Coates Fulton

Big Lost

River Valley 

Big Lost River

Little Lost River

Birch Creek

Big Lost River Valley groundwater

Little Lost River Valley groundwater

Birch Creek Valley groundwater

EXPLANATION

Figure 15. Stable isotope ratios of oxygen (δ18O) at different elevations for surface water and groundwater from the 

Birch Creek, Little Lost River, and Big Lost River valleys, eastern Idaho.
52 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Regional groundwater generally had larger δ2H and δ18O 

values, with much larger δ2H and δ18O values in regional 

groundwater from wells ML 19, ML 22, and ML 23 southwest 

of Mud Lake due to recharge of evaporated surface water 

used for irrigation (fig. 11), than streams and groundwater 

from the LLR and BC valleys (figs. 27AA–BB and 28U). 

Mixing of BC valley groundwater, regional groundwater, and 

recharge of water from BC and (or) the BLR that underwent 

evaporation caused most δ2H and δ18O values in natural 

groundwater from the Northeast, Southeast, and northern 

part of the Central INL Areas to be intermediate between the 

δ2H and δ18O values in BC valley and regional groundwater 

(fig. 28U). Similarly, most δ2H and δ18O values in natural 

groundwater from the Northwest, Southwest, and southern 

part of the Central INL Areas were either similar to δ2H and 

δ18O values in groundwater from the LLR valley or between 

δ2H and δ18O values for groundwater from the LLR valley and 

the BLR, indicating that most groundwater in this part of the 

INL was either groundwater from the LLR valley or a mixture 

of groundwater from the LLR valley and infiltration recharge 

from the BLR.

Stable Isotope Ratios of Carbon

The δ13C values, measured from dissolved inorganic 

carbon, ranged from -15 to -3.9 permil (table 15). The δ13C 

values in the study area reflected the competing influence 

of dissolution of carbonate minerals with large δ13C values 

and infiltration recharge from streams and irrigation water 

that transported soil CO2 with small δ13C values from the 

unsaturated zone to the aquifer. Consequently, δ13C values are 

useful for identifying where these processes have influenced 

the chemistry of groundwater. For example, the large δ13C 

values in geothermal water (figs. 27CC and 28V) from the 

Beaverhead Mountains were due to significant dissolution 

of carbonate minerals, the smaller δ13C values in regional 

groundwater probably were due to infiltration of irrigation 

water, and the intermediate values in tributary valley 

groundwater were due to dissolution of carbonate minerals 

and, where irrigation occurs, infiltration of irrigation water.

The δ13C values in natural groundwater from the North 

INL Area were larger than values in most other natural 

groundwater (fig. 27CC) because the source of water to this 

Area was BC and groundwater from the BC valley, both 

of which had large δ13C values (fig. 28V), and there was no 

irrigation in the BC valley to facilitate transport to the aquifer 

of soil CO2 with small δ13C values. Natural groundwater in 

the Northeast, Central, Northwest, and Southwest INL Areas 

had δ13C values that were similar to δ13C values in tributary 

valley groundwater and larger than δ13C values in regional 

groundwater. The complex carbon system in these Areas 

probably was influenced by dissolution of carbonate minerals, 

transport of soil CO2 to the aquifer through infiltration of the 

BLR, and mixing of tributary valley groundwater with either 

regional groundwater or surface water from the BLR. The δ13C 

values in natural groundwater from the Southeast INL Area 

were generally smaller than δ13C values in tributary valley 

groundwater, larger than δ13C values in regional groundwater, 

and increased in the downgradient direction (fig. 28V). 

Lithium concentrations indicate that the source of groundwater 

in the Southeast INL Area was regional groundwater 

(fig. 28R), so the increasing δ13C values in groundwater as it 

flows southeastward may be due to continual dissolution of 

carbonate minerals in the aquifer matrix or increased mixing 

with tributary valley groundwater.

Small, outlier δ13C values were measured in groundwater 

from USGS 22 and USGS 89, in the Northwest and Southwest 

INL Areas, respectively. These small δ13C values may have 

resulted from transport of soil CO2 from the unsaturated zone 

to the aquifer during infiltration recharge of precipitation 

(USGS 22) or the BLR (USGS 89).

Stable Isotope Ratios of Sulfur

The δ34S values measured from sulfate in water from 

47 sites ranged from 1.6 to 16.0 permil (table 15; fig. 28W). 

These values included measurements from two wells (USGS 

sites 433852112165201 and 431857112405501) from 

Wood and Low (1988) that were included in figure 28W

to provide additional information about δ34S values in 

regional groundwater.

The statistical distribution of δ34S values (fig. 27DD) 

shows that δ34S values generally were larger in regional 

groundwater than in surface water or tributary valley 

groundwater, the median δ34S value was larger in surface 

water than tributary valley groundwater, natural groundwater 

from the Northeast and Southeast INL Areas had δ34S values 

similar to regional groundwater, and natural groundwater 

from the North, Central, Northwest, and Southwest INL Areas 

had δ34S values similar to surface water and tributary valley 

groundwater. The spatial distribution of δ34S values (fig. 28W), 

however, provided a different, and more informative analysis 

because a limited number of δ34S values from sources of 

recharge to the INL (BLR, tributary valley groundwater, 

regional groundwater) were available. Therefore, δ34S values 

in natural groundwater were used to identify representative 

δ34S values from sources of recharge.

Regional groundwater contained four large δ34S values 

(ranging from 11.6 to 16.0 permil) and, at sites influenced 

by geothermal water (ML 29) or irrigated with surface water 

(Reno Ranch, ML 22), three smaller δ34S values (ranging 

from 5.1 to 8.3 permil). Consequently, there is uncertainty 

about typical δ34S values in regional groundwater. However, 

δ34S values in natural groundwater from the Northeast and 

Southeast INL Areas, where recharge is primarily from 

regional groundwater, ranged from 9.0 to 11.9 permil and 

were larger than δ34S values in surface water, tributary 

valley groundwater, and other natural groundwater. Thus, 

most regional groundwater entering the INL must have 

δ34S values greater than 9 permil and probably greater than 

10 permil (fig. 28W).
Geochemistry of Surface Water and Groundwater 53

The δ34S values in groundwater from the BLR, LLR, 

and BC valleys were (or ranged from) 1.6, 1.8 to 3.3, and 

7.6 to 7.7 permil, respectively. The small δ34S values from 

the BLR and LLR valleys were from groundwater that was 

influenced by irrigation, so sulfur in soil amendments may 

have lowered the δ34S values in the groundwater. The δ34S 

values in natural groundwater from the North and Northwest 

INL Areas, directly south of the BC and LLR valleys, ranged 

from 6.1 to 8.6 permil (fig. 28W). These δ34S values indicate 

that groundwater entering the ESRP aquifer from the LLR and 

BC valleys probably had δ34S values of about 7 to 8 permil.

Natural groundwater from the Central and Southwest 

INL Areas had δ34S values that ranged from 5.2 to 5.8 permil. 

These δ34S values were smaller than δ34S values in the 

hydrologically upgradient North and Northwest INL Areas, 

indicating that groundwater in the Central and Southwest INL 

Areas was a mixture of upgradient groundwater and another 

source of water with smaller δ34S values. The δ34S values in 

groundwater from the Central and Southwest INL Areas were 

from sites located near or hydrologically downgradient of 

the BLR channel or INL spreading areas (figs. 3B and 28W). 

A water sample collected from the BLR near Arco had a 

fairly small δ34S value of 4.4 permil, so water in the Central 

and Southwest Areas probably was a mixture of upgradient 

groundwater and water from the BLR.

Stable Isotope Ratios of Nitrogen

The δ15N values, measured from nitrate in groundwater 

from 38 sites, ranged from 4.7 to 9.5 permil (table 15). Most 

of the δ15N values were from natural groundwater, although 

there were some δ15N values in groundwater from the LLR and 

BC valleys (6.0–7.0 permil), regional groundwater northwest 

of Mud Lake (6.9 and 9.5 permil), regional groundwater 

southwest of Mud Lake (4.7 and 5.1 permil), and deep 

groundwater (5.8 to 6.3 permil) (figs. 27EE and 28X). No δ15N 

values were measured from surface water.

The δ15N values in natural groundwater from the eastern 

part of the INL were larger in the north (δ15N values greater 

than or equal to 6.3 permil) than in the south (less than or 

equal to 5.4 permil). These δ15N values were consistent with 

recharge in the northern and southern regions of regional 

groundwater northwest and southwest of Mud Lake, 

respectively. The δ15N values were greater than or equal to 

5.9 permil in natural groundwater from the North, Central, 

and Northwest INL Areas, which was consistent with recharge 

of groundwater from the LLR and (or) BC valleys. The δ15N 

values in natural groundwater from the Southwest INL Area 

extended over a wide range (5.4 to 8.1 permil), but these 

δ15N values were not used to identify sources of recharge to 

this Area because δ15N values were not available for several 

potential sources of recharge (BLR, groundwater from the 

BLR valley, and groundwater from the Lost River Range).

Isotope Ratios of Helium 

The Rs/Ra ratios, measured in groundwater from 37 sites, 

ranged from 0.001 to 9.70 (table 15; fig. 28Y). These ratios 

included a measurement from USGS 121 (1.75; fig. 28Y), 

from Busenberg and others (2001), that was included with 

the basic data set (table 15) to provide additional information 

about Rs/Ra ratios in natural groundwater from the Northwest 

INL Area. 

Most of the Rs/Ra ratios were from natural groundwater, 

although there were a few Rs/Ra ratios from tributary valley 

groundwater, regional groundwater, and contaminated 

groundwater. Most natural groundwater had Rs/Ra ratios that 

ranged from 0.99 to 2.07, although groundwater from ANP 9 

and Area II had Rs/Ra ratios of 0.001 and 0.003, respectively, 

and groundwater from USGS 27 had an Rs/Ra ratio of 9.70 

(figs. 27FF and 28Y). One Rs/Ra ratio was measured from 

tributary valley groundwater (0.99 from P&W2), two Rs/Ra

ratios were measured from regional groundwater (1.13 and 

0.67 from ML 22 and USGS 101, respectively), and three 

Rs/Ra ratios were measured from contaminated groundwater 

(0.69–7.46).

Identification of the sources of helium in groundwater 

provided information about sources of water to the 

groundwater, and figure 12 illustrates the changes in helium 

concentrations and Rs/Ra ratios in groundwater depending on 

whether helium was derived from the atmosphere, mantle, 

crust, radioactive decay of tritium (tritiogenic helium), or 

from dissolution of basalt. For example, natural groundwater 

from ANP 6, No Name 1, and PSTF Test in the North INL 

Area, plus P&W2 at the mouth of the BC valley, had helium 

concentrations (except for No Name 1 which contains excess 

air; Busenberg and others, 2001) and Rs/Ra ratios similar to 

values in the atmosphere, which suggested that recent recharge 

from BC (or the BLR at PSTF Test) was the primary source 

of water at these wells. Likewise, helium concentrations and 

Rs/Ra ratios in regional groundwater from ML 22 were similar 

to values in the atmosphere, indicating that surface water used 

for irrigation was the likely source of recharge at this well.

Helium concentrations and Rs/Ra ratios in groundwater 

from the Northeast INL Area indicated that sources of helium 

were from the atmosphere (USGS 32), mantle (USGS 27), 

crust (ANP 9, USGS 29), and radioactive decay of tritium 

(USGS 29, USGS 32). Thus, sources of recharge at these 

wells probably included surface water used for irrigation 

in the Mud Lake area (from the 1960s to the 1970s when 

large quantities of tritium were in the atmosphere) at 

USGS 32, upwelling geothermal water (USGS 27), regional 

groundwater (ANP 9), and regional groundwater plus surface 

water used for irrigation in the Mud Lake area (USGS 29). 
54 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Following the same logic for other natural groundwater, 

sources of recharge in the 

1. Southeast INL Area included the BLR (USGS 14), 

groundwater used for irrigation that equilibrated with 

the atmosphere (Atomic City), and regional groundwater 

plus surface water used for irrigation in the Mud 

Lake area (Arbor Test 1, Area II, USGS 1, USGS 2, 

USGS 100); 

2. Central INL Area included the BLR (USGS 103, NPR 

Test) and the BLR plus groundwater from the LLR and 

(or) BC valleys (USGS 5, USGS 17); 

3. Northwest INL Area included the BLR plus groundwater 

from the LLR valley (most sites), groundwater from 

the LLR valley (USGS 19), groundwater from the Lost 

River Range (and perhaps precipitation) at USGS 23, 

and recent recharge from precipitation (USGS 22); and 

4. Southwest INL Area included the BLR plus groundwater 

from the BLR and LLR valleys and (or) the Lost River 

Range (all sites).

Stable Isotope Ratios of Strontium and Radioisotope 

Ratios of Uranium

The 87Sr/86Sr ratios, measured in water from 57 sites, 

ranged from 0.70935 to 0.71434 and 234U/238U activity ratios, 

measured in water from 51 sites, ranged from 1.54 to 3.14 

(table 16; figs. 28Z–AA). These ratios included 87Sr/86Sr 

ratios from three wells (Howe City well, well 52098-1, and 

well 52098-2; fig. 28Z) from Johnson and others (2000) 

and a 234U/238U activity ratio from the Crooked Creek well 

(fig. 28AA) from Roback and others (2001). These ratios were 

included with the basic data set (table 16) and in boxplots 

(figs. 27GG–HH) to provide additional information about 87Sr/86Sr and 234U/238U ratios in tributary valley and (or) 

regional groundwater.

The 87Sr/86Sr ratios in surface water varied widely 

(fig. 27GG), with larger ratios from the LLR (0.71256) and 

BC (0.71198) and a smaller ratio from the BLR (0.71056). The 

234U/238U activity ratios from surface water were available only 

at two sites from the BLR, and these 234U/238U activity ratios 

were smaller than ratios in most other water in the study area 

(fig. 27HH). The 87Sr/86Sr and 234U/238U ratios in streams may 

fluctuate seasonally depending on the relative percentages of 

surface water (that is, tributary creeks, overland runoff, and 

direct precipitation) and groundwater inflow that contributed 

to stream discharge.

The 87Sr/86Sr and 234U/238U ratios were larger in 

tributary valley groundwater than in regional groundwater 

(figs. 27GG–HH). Consequently, natural groundwater from the 

northern part of the INL generally had the largest 87Sr/86Sr and 234U/238U ratios due to recharge from streams and groundwater 

from the tributary valleys. Natural groundwater from the 

eastern-to-south-central part of the INL (figs. 28Z–AA) 

had 87Sr/86Sr and 234U/238U ratios that generally increased 

in the downgradient direction, probably due to mixing 

between tributary valley and regional groundwater. Natural 

groundwater from the western part of the INL that was near 

or downgradient of the BLR had 87Sr/86Sr and 234U/238U ratios 

that were similar to or slightly smaller than ratios from the 

BLR, probably due to recharge from the BLR. Groundwater 

from USGS 22, in the Northwest INL Area, had the smallest 

234U/238U activity ratio (1.54) and concentration of uranium 

(0.43 μg/L) in oxic groundwater, probably because the source 

of water at USGS 22 was precipitation and therefore all of 

the uranium in this groundwater was from the dissolution of 

basalt minerals.

The interpretation that the distribution of 87Sr/86Sr and 234U/238U ratios was largely explained by mixing of tributary 

valley groundwater with regional groundwater and (or) 

recharge from the BLR differs from the interpretations of 

preferential flow paths of Johnson and others (2000) and 

Roback and others (2001). They based their interpretations 

on contours of 87Sr/86Sr and 234U/238U ratios, with the contours 

delineating north-to-south trending zones consisting of 

alternating low and high isotope-ratio zones. Johnson and 

others (2000, p. 873) argued that recharge from the BLR did 

not cause the two low isotope-ratio zones because the 87Sr/86Sr 

ratio of the BLR (0.71056) was larger than the ratios in the 

low isotope-ratio zones (0.70951–0.71047; fig. 28Z), whereas 

Roback and others (2001, p. 1,139) argued that mixing did 

not readily explain the shape or location of the high or low 

isotope-ratio zones. No isotopic data separated the two 

low‐isotope zones (Roback and others, 2001, fig. 2), however, 

so different contours could easily be drawn that merge the two 

low isotope-ratio zones into a single low isotope-ratio zone 

that follows the channel of the BLR, similar to the ranges of 

isotope ratios in figure 28AA, for example. Additionally, the 

smallest 87Sr/86Sr ratio (0.70951), from USGS 22, represented 

the 87Sr/86Sr ratio in recharge from precipitation (Busenberg 

and others, 2001). This 87Sr/86Sr ratio was smaller than the 87Sr/86Sr ratio from the BLR (0.71056), which was collected 

prior to peak runoff (U.S. Geological Survey, 2014), and 

shows that the 87Sr/86Sr ratio in the BLR could easily be 

smaller when snowmelt is at a maximum during periods of 

peak runoff and recharge.

Environmental Tracers

Tritium and Terrigenic Helium

Tritium activities ranged from -190±70 to 

39,600±380 pCi/L, although the largest tritium activity in 

uncontaminated groundwater was 160.9±0.4 pCi/L (table 17). 
Geochemistry of Surface Water and Groundwater 55

The Heterr values ranged from 0 to 97 percent (table 17) and 

generally had an inverse relation with tritium activities; small 

tritium activities corresponded to large Heterr values and large 

tritium activities corresponded to small Heterr values (fig. 14).

For example, geothermal water and most deep groundwater 

had small tritium activities but large Heterr values, results 

that were consistent with old groundwater, and regional 

groundwater had smaller tritium activities and larger Heterr

values than tributary valley groundwater (figs. 27II–JJ), 

results that were consistent with regional groundwater 

that had an older mean groundwater age than tributary 

valley groundwater. The tritium activities in surface water 

indicated that surface water consists primarily of young water 

(figs. 13A–B and 27II).

Natural groundwater from the Northeast INL Area 

generally had small tritium activities and large Heterr values, 

consistent with old groundwater and, at wells USGS 26, 

USGS 27, and USGS 31, some geothermal water, whereas 

natural groundwater from the Northwest INL Area generally 

had large tritium activities and small Heterr values, consistent 

with rapid, focused recent recharge (figs. 14 and 28BB–CC). 

Tritium activities and Heterr values indicated that natural 

groundwater from the (1) Southeast INL Area was a mixture 

of young and old groundwater that consisted of various 

amounts of recent recharge and regional groundwater and 

(2) Central INL Area was either (a) young groundwater 

or a mixture of young and old groundwater that contained 

large amounts of recent recharge or (b) old groundwater 

that contained small amounts of recent recharge and, at 

USGS 18, some geothermal water. Tritium activities in natural 

groundwater from the Southwest INL Area indicated that this 

was young groundwater and Heterr values of 10–40 percent 

indicated that large amounts of recent recharge mixed with 

old groundwater that probably originated in the LLR valley. 

Natural groundwater from the North INL Area had small 

tritium activities and Heterr values, in contrast to the inverse 

relation of these chemical constituents in other water, and 

indicated that this Area contained old groundwater that 

consisted of slow, diffuse recent recharge (fig. 14). Although 

rapid, focused recharge was the more common method of 

recharge in the fractured basalt ESRP aquifer at the INL, 

slow, diffuse recharge may have occurred in the North INL 

Area where surface water seeped through thick accumulations 

of sediment (Whitehead, 1992) and fine-grained lacustrine 

sediment at playas 3 and 4 (figs. 3B and 4B).

Tritium activities in natural groundwater from several 

wells did not conform to the general distribution of tritium. 

For example, tritium activities indicated that groundwater 

from USGS 29, in the Northeast INL Area, was not old 

groundwater but a mixture of young and old groundwater 

(fig. 14). The young groundwater at USGS 29 was probably 

from recent recharge of surface water used for irrigation in 

the Mud Lake area. Tritium activities also indicated that old 

groundwater, instead of young groundwater or a mixture of 

young and old groundwater, was present at wells USGS 23, 

USGS 86, USGS 117, and possibly USGS 119 (table 17) in 

the Northwest and Southwest INL Areas. The presence of 

old groundwater at these wells may be due to (1) recharge 

of old groundwater from the Lost River Range (USGS 23), 

(2) a location (USGS 86) that received minimal young 

recharge from the BLR (Bennett, 1990), or (3) small hydraulic 

conductivities (0.01–6.5 ft/d; log K values of -2.00–0.81 ft/d 

in table 11) that restricted throughflow of groundwater 

(USGS 86, USGS 117, USGS 119).

Tritium/Helium-3, Chlorofluorocarbons, and Sulfur 

Hexafluoride

Based on concentrations and (or) ratios of 3H/3He, 

CFCs, and SF6, the estimated age of the young fraction of 

groundwater ranged from 2–5 to much greater than (>>) 

55 (or “old”)22 years before the sampling date (table 17). 

The estimated age of the young fraction of groundwater in 

tributary valley and regional groundwater was determined 

at five sites, and each of the sites contained some young 

groundwater. Concentrations of CFCs and SF6 in deep 

groundwater, and natural groundwater from USGS 6 and 

USGS 23, were either zero or small. These concentrations, and 

the small tritium activities in groundwater from these wells, 

indicated that deep groundwater, and natural groundwater 

from USGS 6 and USGS 23, consisted primarily of old 

groundwater. The absence of young groundwater at USGS 6 

and USGS 23 was probably due to the 8–10-mi distance of 

USGS 6 downgradient from sources of young recharge at 

playas 3 and 4 (figs. 3B and 9) and groundwater at USGS 23 

consisting of old groundwater from the Lost River Range 

(Busenberg and others, 2001). All other natural groundwater 

with concentrations and (or) ratios of 3H/3He, CFCs, and SF6

were estimated to contain some young groundwater, even if 

only in small amounts. For example, natural groundwater from 

the Northeast INL Area had the youngest estimated age of the 

young fraction groundwater (fig. 27KK). However, the small 

tritium activities and large Heterr values in groundwater from 

the Northeast INL Area indicated that only a small fraction of 

this groundwater was young groundwater.

22The difference between estimated ages >>55 years before the sampling date and “old” was that no CFCs were detected in groundwater samples with 

estimated ages >>55 years, and thereby could be determined to predate the release of CFCs to the atmosphere, whereas “old” groundwater contained CFCs 

that, based on small tritium activities in the groundwater, was presumed to be from advective and diffusive transport of CFCs through the unsaturated zone 

(Busenberg and others, 2001).
56 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Carbon-14

Carbon-14 age dating indicated that geothermal water 

from INEL-1 10,300 feet was about 35,000 years old (Mann, 

1986). Carbon-14 ages were not determined for other 

groundwater in the study area because tritium, an indicator of 

recent recharge, was present in nearly all other groundwater. 

Carbon-14 activities, however, may be useful for identifying 

sources of recharge. For example, modern carbon-14 activities 

(>100 pmC) should be present in recent recharge of surface 

water (with an estimated percent modern carbon of 120; 

fig. 27LL), plus any CO2 in the unsaturated zone in equilibrium 

with the atmosphere that was transported to the aquifer in 

infiltrating surface water. Conversely, marine carbonates 

in the mountains, or in sediment in the unsaturated zone or 

ESRP aquifer, typically have carbon-14 activities of 0 pmC 

(Clark and Fritz, 1997, table 8-1), and dissolution of marine 

carbonates will reduce the carbon-14 activity in groundwater. 

For example, the small carbon-14 activities in natural 

groundwater from the northern part of the INL, 21–37 pmC 

(fig. 28DD), were due to dissolution of marine carbonates.

The relation between carbon-14 activity and the mean age 

of natural groundwater was evaluated from a plot of carbon-14 

and tritium activities (fig. 16), with larger tritium activities 

corresponding to a younger mean age and smaller tritium 

activities corresponding to an older mean age. The δ13C values 

also were included to provide information about the sources 

of carbon in the groundwater. Natural groundwater plots along 

two trends in figure 16, with groundwater from the Northeast 

and Southeast INL Areas plotting along a steeper slope, and 

generally having a smaller tritium activity and δ13C value for 

a given carbon-14 activity, than groundwater from the North, 

Central, Northwest, and Southwest INL Areas. These two 

trends indicated that groundwater from the Northeast and 

Southeast INL Areas had a different origin than groundwater 

0.1

1.0

10.0

100.0

20 30 40 50 60 70 80 90

Tritium, in picocuries per liter

Carbon-14, in percent modern carbon

14 -9.29

22 -13.55

18 -7.37

23 -5.72

ANP 6

-6.06

19

-7.06

15 -8.01

Site 14 -8.17

P&W 2 -6.13

Site 17 -8.48

26 -8.61

INEL 1 WS

-8.88

32 -9.47

98 -8.84

31 -9.39

11 -9.17

1

-10.71

99 -9.68

125 -9.38

NPR Test -9.90

100

-11.17

17 -10.09

97 -10.09

12

-10.18 102 -9.81

29 -11.75

Ruby Farms -9.1

Old groundwater

Young groundwater

Mixture of young and old groundwater

Increasing groundwater age

Increasing groundwater age

-9.10 

Tributary valley groundwater

Deep groundwater

Northeast and Southeast INL Areas

North, Central, Northwest, and Southwest INL Areas

Carbon-13/carbon-12 (δ13C)

EXPLANATION

Figure 16. Carbon-14 activities, tritium activities, and carbon-13/carbon-12 (δ13C) values in groundwater, Idaho National 

Laboratory and vicinity, eastern Idaho.
Geochemistry of Surface Water and Groundwater 57

from the North, Central, Northwest, and Southwest INL 

Areas, a conclusion that was consistent with the interpretation 

from lithium concentrations that groundwater from these 

Areas was from regional groundwater and tributary valley 

water, respectively. Along each of the trends, δ13C values 

also generally increased as tritium and carbon-14 activities 

decreased. These results indicated that dissolution of marine 

carbonates in interbed sediment occurs throughout the ESRP 

aquifer at the INL.

Distinguishing Chemical and Isotopic 

Characteristics for Each Water Group

Knowledge of the distinguishing chemical and isotopic 

characteristics for each water group will help identify the 

sources of water at the INL. This synopsis of the chemical 

and isotopic constituents that distinguish each of the water 

groups is based on the analysis of the chemical and isotopic 

constituents presented above and the data presented in 

figures 27A–LL and 28A–DD.

Surface Water

Surface water generally was dilute, had small 

concentrations of helium, major ions, boron, and lithium, 

and was a Ca-HCO3 water type. Surface water generally was 

young water characterized by large tritium activities, and 

infiltration recharge of surface water may transport soil CO2

with light δ13C values to the aquifer. The δ2H and δ18O values 

in surface water ranged from heavy to light, with the heaviest 

values in Camas Creek and Mud Lake, intermediate values in 

the BLR and LLR, and lighter values in BC. The LLR and BC 

had large 87Sr/86Sr ratios, although the 87Sr/86Sr ratio from the 

BLR was much smaller.

Tributary Valley Groundwater

Tributary groundwater was cold, had small 

concentrations of potassium, fluoride, silica, boron, and 

lithium, and primarily was a Ca-HCO3 type water. Because 

of the influence of agriculture, groundwater in the lower parts 

of the BLR and LLR valleys had relatively large specific 

conductance values and nitrate concentrations. The δ2H and 

δ18O values in tributary valley groundwater ranged from heavy 

to light, with heavy, intermediate, and light δ2H and δ18O 

values in groundwater from the BLR, LLR, and BC valleys, 

respectively. The 87Sr/86Sr and 234U/238U ratios in groundwater 

from the LLR and BC valleys were large.

Regional Groundwater

The chemistry of regional groundwater can be 

categorized into three groups—groundwater that was either 

extensively (North, West, and Southwest Mud Lake Areas; 

table 10) or slightly (East Mud Lake and Southeast INL 

Boundary Areas) influenced by agricultural inputs and 

groundwater that was influenced by upwelling geothermal 

water (groundwater with geothermal input). Groundwater 

extensively influenced by agricultural inputs typically 

was a mixed cation-HCO3 water type with large specific 

conductance, large concentrations of CO2, major ions (except 

for fluoride), barium, boron, lithium, strontium, and uranium, 

heavy δ2H and δ18O values, and was young water or a mixture 

of young and old water. Groundwater slightly influenced 

by agricultural inputs was typically a Ca-HCO3 water type 

with small specific conductance, small concentrations of 

calcium, magnesium, bicarbonate, chloride, sulfate, barium, 

boron, and strontium, large concentrations of fluoride and 

silica, and was old water or a mixture of young and old water. 

Groundwater influenced by upwelling geothermal water was 

a mixed cation-HCO3 or Na-HCO3 water type, was anoxic or 

undersaturated with oxygen, had small specific conductance, 

small concentrations of CO2, calcium, chloride, sulfate, nitrate, 

strontium, and uranium, large concentrations of sodium, 

potassium, fluoride, silica, and lithium, and was old water. 

Regional groundwater can be distinguished from tributary 

valley groundwater by warmer groundwater temperatures, 

larger concentrations of sodium, potassium, fluoride, silica, 

boron, and lithium, and, compared with groundwater from the 

LLR and BC valleys, heavier δ2H and δ18O values, lighter δ13C 

values, and smaller 87Sr/86Sr and 234U/238U ratios.

Geothermal Water

Geothermal water consisted of three distinct water types. 

Site ML 58 (Warm Spring), located high in the Beaverhead 

Mountains, was a Ca-HCO3 type water with a large fluoride 

concentration, a large δ13C value, an extremely large 87Sr/86Sr 

ratio, and was a mixture of young and old water. Site ML 57 

(Lidy Hot Springs), located in the foothills of the Beaverhead 

Mountains, was a Ca-SO4 type water with large specific 

conductance, large calcium, potassium, sulfate, fluoride, 

boron, lithium, and strontium concentrations, a large δ13C 

value, δ2H and δ18O values that plot to the left of the LMWL 

(fig. 11), and consisted of old water. Water from borehole 

INEL-1, deep below the ESRP, was a Na-HCO3 type water 

with large specific conductance, large sodium, potassium, 

fluoride, silica, boron, and lithium concentrations, small 

calcium and magnesium concentrations, small 87Sr/86Sr ratios, 

and, for water from site INEL-1 10,300 feet, was anoxic and 

very old.
58 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Deep Groundwater

Deep groundwater generally had small specific 

conductance, small concentrations of DO, chloride, and 

nitrate, small δ18O and large δ13C values, was a mixed 

cation‐HCO3 water type, and, based on small tritium activities, 

was primarily old groundwater. However, some important 

chemical differences existed between deep groundwater from 

different sites. For example, deep groundwater from Site 14 

and USGS 7 had large temperatures (16.3 and 18.8 °C), large 

concentrations of helium (38.4 and 149 cm3 STP/g × 10-8), 

large percentages of Heterr (91 and 97 percent), and USGS 7 

plots between natural groundwater and geothermal water 

from INEL-1 on a trilinear diagram (fig. 10A), all of which 

indicated that some mantle helium, in upwelling geothermal 

water (fig. 14), was present in deep groundwater from these 

two wells. Site EBR 1, on the other hand, had a small helium 

concentration (5.5 cm3 STP/g × 10-8), a fairly small Heterr

(27 percent), and a tritium activity (-3.2±13 pCi/L) consistent 

with either old groundwater or a mixture of young and old 

groundwater (table 17). The small helium concentration and 

percentage of Heterr indicated that deep groundwater at EBR 

1 contained some recent recharge. The location of EBR 1 

(fig. 9) indicates that the source of recent recharge probably 

was the BLR, and the estimated age of the young fraction of 

groundwater indicated that the recent recharge occurred at 

least 45 years prior to collection of the water sample in 1996 

(Busenberg and others, 2001, table 9).

Contaminated Groundwater

Potential sources of recharge to contaminated 

groundwater included wastewater discharged at site facilities 

as well as tributary groundwater and infiltration of the BLR 

and, at TAN, BC. These potential sources of water resulted 

in a wide variety of hydrochemical facies for contaminated 

groundwater, although most contaminated groundwater was a 

Ca-HCO3 water type (fig. 10A–B). Concentrations of fluoride, 

silica, and lithium were small, and discharge of wastewater 

resulted in large specific conductance, large calcium, sodium, 

chloride, and sulfate concentrations, and large tritium 

activities. Infiltration of wastewater or the BLR caused some 

contaminated groundwater to have helium concentrations 

similar to air-water equilibrium concentrations, light δ13C 

values, and slightly evaporated δ2H and δ18O values (in 

groundwater south of the INTEC infiltration ponds).

Discharge of large amounts of certain waste 

constituents in wastewater from specific site facilities 

resulted in contaminated groundwater with distinct chemical 

characteristics at each site facility. For example, contaminated 

groundwater at ATRC had large calcium, sulfate, and 

chromium concentrations, large tritium activities, and 

was a Ca-SO4 water type. Contaminated groundwater at 

INTEC had large magnesium, sodium, chloride, and barium 

concentrations, large tritium activities, and included some 

groundwater that was a mixed cation-Cl water type, whereas 

groundwater at NRF had large calcium, magnesium, sodium, 

chloride, and sulfate concentrations and included some 

groundwater that was a mixed cation-mixed anion water 

type. Contaminated groundwater at RWMC had large sulfate 

concentrations and large tritium activities, contaminated 

groundwater at TAN had small DO concentrations, large 

sodium and chloride concentrations, and large tritium 

activities, and some contaminated groundwater from RWMC 

and TAN was a mixed cation-mixed anion water type.

Natural Groundwater

Natural groundwater generally was well oxygenated, 

indicating that widespread oxidation-reduction reactions 

do not occur in groundwater at the INL. Other chemical 

characteristics in natural groundwater typically varied across 

the INL due to the chemical diversity of the source waters. 

For example, specific conductance was largest in natural 

groundwater downgradient of irrigated lands in the Mud 

Lake area and the LLR valley. Most major ion, and some 

dissolved metal, concentrations in natural groundwater also 

followed a general pattern of either increasing or decreasing 

concentrations in a southeast-to-northwest direction across 

the INL in response to recharge from carbonate and silicate 

terranes north and east of the INL, respectively. Agricultural 

inputs prevented these patterns of increasing or decreasing 

concentrations from being entirely consistent. However, 

three elements, fluoride, silica, and lithium, show a consistent 

decrease in concentrations in a southeast-to-northwest 

direction across the INL because these elements primarily 

were derived from dissolution of silicate minerals east of the 

INL and concentrations of these elements were not affected by 

agricultural inputs. Although major ion and dissolved metal 

concentrations varied across the INL, the dominant anion in 

groundwater was bicarbonate. As a result, the hydrochemical 

facies of natural groundwater was either a Ca-HCO3 or a 

mixed cation-HCO3 water type.

The δ2H and δ18O values in natural groundwater also 

varied widely across the INL because of the widely different 

values in sources of recharge. For example, for the three 

primary sources of recharge to the INL, δ18O values were 

typically less than -17.90 permil in groundwater from the LLR 

and BC valleys, were probably about -17.4 or -17.17 permil 

in the BLR (on the ESRP), and ranged from -17.90 to 

-14.84 permil in regional groundwater (fig. 11). 

About one-half of the Rs/Ra ratios in natural groundwater 

were at or slightly larger than 1.0, consistent with helium from 

young recharge. Ratios less than 1.0 were present in some 

natural groundwater from the Northeast and Southeast INL 

Areas, consistent with groundwater containing crustal helium 

and having a long aquifer residence time, and an Rs/Ra ratio of 

9.70 for a groundwater sample (USGS 27) from the Northeast 

INL Area indicated that this groundwater contains geothermal 

water. Tritium activities indicated that natural groundwater in 
Geochemistry of Surface Water and Groundwater 59

the North and Northeast INL Areas and the northern part of 

the Central INL Area consisted primarily of old groundwater, 

the Southeast INL Area consisted of a mixture of young and 

old groundwater, and the Northwest and Southwest INL 

Areas and the southern part of the Central INL Area consisted 

primarily of young groundwater or a mixture of young and 

old groundwater.

Temporally Variable Water Chemistry

Temporally variable groundwater chemistry occurs 

at many locations at the INL (Robertson and others, 1974; 

Bartholomay and others, 2012; Davis and others, 2015) due 

to temporally variable natural and anthropogenic sources of 

recharge. Temporally variable sources of recharge include 

(1) episodic recharge of surface water with different, and 

variable, chemical compositions than groundwater at the INL; 

(2) changing wastewater disposal practices at site facilities; 

and (3) changing irrigation practices north (tributary valley 

groundwater) and east (regional groundwater) of the INL. 

Examples of temporally variable sources of recharge include 

(1) episodic recharge from the BLR (Bennett, 1990), LLR, 

and BC; (2) changes in method of discharge of wastewater 

from injection wells to infiltration ponds and relocation of 

infiltration ponds (Davis and others, 2013); and (3) increased 

use of groundwater for irrigation (Goodell, 1988) and 

changing from flood to sprinkler irrigation (Idaho Department 

of Environmental Quality, 2006).

Long-term trends (trends that occur over decades) 

in groundwater chemistry at the INL, which includes the 

influence of irrigation water and wastewater discharge, 

were reported by Bartholomay and others (2012) and Davis 

and others (2015). The long-term trends showed that for 

groundwater unaffected by wastewater disposal (that is, 

natural groundwater), changes to groundwater chemistry 

because of anthropogenic inputs was generally gradual and 

of small magnitude. In contrast, wet and dry climate periods 

produce highly variable infiltration from surface water 

sources of recharge that influence the natural chemistry of 

groundwater at the INL.

Infiltration of surface water produces changes in the 

chemistry of groundwater at the INL because surface water 

is generally more dilute than groundwater at the INL and 

may occur as focused, episodic recharge. The chemistry of 

surface water also varies in a seasonal manner in response 

to (1) the relative percentages of surface water inflow (that 

is, tributary creeks, overland runoff, and direct precipitation) 

and groundwater inflow that contributes to stream discharge 

and lake storage; (2) agricultural inputs; and (3) the amount 

of evaporation that the stream or lake has undergone. Surface 

water, therefore, has significant potential for producing 

temporally variable chemistry in groundwater at the INL. 

Consequently, the temporal variability of interest for this study 

are the temporal changes in the chemistry of surface water 

and the changes in groundwater geochemistry associated with 

focused, episodic recharge of surface water.

Surface Water

Time-series plots of bicarbonate, nitrate, and the stable 

isotopes of hydrogen and oxygen were prepared to identify 

changes in surface water chemistry and the primary cause 

of the change. Bicarbonate was used to identify the relative 

amounts of surface water and groundwater inflow to the 

streams and Mud Lake because groundwater in the study 

area has much larger concentrations of bicarbonate (table 13) 

than does meteoric water (Bartholomay and others, 2015; 

Busenberg and others, 2001). Nitrate was used to identify 

whether agricultural inputs influenced the chemistry of surface 

water, and the stable isotopes of hydrogen and oxygen were 

used to identify whether evaporation, which could affect the 

concentrations of dissolved constituents, occurs.

Bicarbonate and Nitrate

Concentrations of bicarbonate and nitrate (table 4), and 

monthly discharge or daily storage volume (U.S. Geological 

Survey, 2014), were plotted for the BLR near Arco, the LLR 

near Howe, and Mud Lake near Terreton (figs. 17A–C). The 

plotted data represent periods of record (1965 through 1970 

for the BLR, 1965 through 1981 for the LLR, and 1968 

through 1978 for Mud Lake) with a high frequency of data 

collection. A low frequency of data collection would make 

it difficult to identify the influence of surface water inflow 

relative to groundwater inflow or agricultural inputs on 

surface water chemistry. Data collection from sites on Birch 

Creek and Camas Creek were infrequent, so the influence 

of surface water inflow compared with groundwater inflow 

or agricultural inputs on surface water chemistry was not 

evaluated for these streams.

Concentrations of bicarbonate (in milligrams per 

liter) ranged from 168 to 291 for the BLR, from 95 to 

233 for the LLR, and from 90 to 183 for Mud Lake. 

Conceptually, bicarbonate should decrease in the streams 

during spring snowmelt and runoff and should increase 

when the stream recedes to base flow. However, the timing 

of increases or decreases of bicarbonate concentrations in 

Mud Lake may not be directly relatable to snowmelt because 

water in Mud Lake was controlled by groundwater inflow, 

groundwater pumping, as well as surface-water inflow during 

spring runoff.

The correlation between bicarbonate concentrations 

and streamflow discharge or volume of lake storage was 

calculated to test whether the concentrations were related 

to stream discharge or volume of lake storage. Correlations 

of -0.70, -0.77, and 0.34 were calculated for the BLR, LLR, 

and Mud Lake, respectively. There was a moderately strong 

negative correlation for the streams, with smaller bicarbonate 

concentrations occurring during high volume discharge 

(spring runoff) and larger concentrations during low volume 

discharge (base flow). The correlation for Mud Lake was 

weak, probably because storage in Mud Lake was controlled 

by primarily by inflows and outflows that were not entirely 

related to snowmelt.
60 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig17a-c

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1965 1966 1967 1968 1969 1970 1971

1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982

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Bicarbonate, in milligrams per liter and monthly

discharge x 0.5, in cubic feet per second

Bicarbonate, in milligrams per liter and

monthly discharge, in cubic feet per second

Bicarbonate, in milligrams per liter and

daily storage, in hundreds of acre feet

Nitrate, in milligrams per liter as nitrogen

Date of sample collection or daily storage measurement

Month of discharge or date of sample collection

A. Big Lost River near Arco

B. Little Lost River near Howe

C. Mud Lake near Terreton

No discharge data

Discharge or storage

Bicarbonate

Nitrate

EXPLANATION

Figure 17. Bicarbonate and nitrate concentrations and monthly discharge or daily storage volume, Idaho National 

Laboratory and vicinity, eastern Idaho. (A) Concentrations and discharge for the Big Lost River near Arco, 1965 through 

1970. (B) Concentrations and discharge for the Little Lost River near Howe, 1965 through 1981. (C) Concentrations and 

storage for Mud Lake near Terreton, 1968 through 1978.
Geochemistry of Surface Water and Groundwater 61

Concentrations of nitrate (in milligrams per liter as 

nitrogen) ranged from 0.02 to 0.59 for the BLR, from 0.03 to 

7.50 for the LLR, and from 0.03 to 1.30 for Mud Lake. 

The range of concentrations is quite large; however, only 10 of 

the 83 total nitrate measurements had nitrate concentrations 

exceeding 0.5 mg/L as N. These infrequent large nitrate 

concentrations indicate that fertilizer applied in irrigation 

areas was only occasionally a significant source of chemical 

constituents to surface water, and indicates that agricultural 

chemicals generally did not influence the chemistry of surface 

water in the study area.

Stable Isotopes of Hydrogen and Oxygen

The δ2H and δ18O values were measured from monthly 

water samples, collected between March 1991 and June 1992, 

from the BLR at Mackay Reservoir, the LLR near Howe, BC 

at Blue Dome, and Mud Lake near Terreton (table 3). The 

δ18O values ranged from -18.00 to -17.05 permil for the BLR, 

-18.25 to -17.80 permil for the LLR, -18.75 to -18.55 permil 

for BC, and -17.85 to -15.55 permil for Mud Lake. The 

range between large and small δ18O values, 0.20 permil for 

BC, 0.45 permil for the LLR, 0.95 permil for the BLR, and 

2.30 permil for Mud Lake, shows that δ18O values were mostly 

uniform in BC, slightly variable in the LLR, moderately 

variable in the BLR, and highly variable in Mud Lake. Part 

of the variability of the δ2H and δ18O values may be due to 

the location of the sampling site. For example, Birch Creek at 

Blue Dome, at an altitude of 6,050 ft (table 11), is likely to be 

less influenced by evaporation than Mud Lake near Terreton at 

an altitude of 4,775 ft.

The δ18O values were plotted on a time series graph 

(figs. 18A–B), along with the daily discharge in the BLR and 

LLR (discharge data were not available for BC) and the daily 

storage volume of Mud Lake (U.S. Geological Survey, 2014). 

The δ18O values of the streams, during 1991 and 1992, ranged 

from heavy to light in a southwest-to-northeast direction (that 

is, δ18O values for the BLR were heavier than for the LLR and 

δ18O values for the LLR were heavier than for BC) and the 

δ18O values from Mud Lake were as heavy, or heavier, than 

those from the BLR (fig. 18).

The δ18O values from BC do not show any evidence 

of evaporation (figs. 11 and 18A). The δ18O values from 

the LLR are slightly heavier in summer than winter, which 

indicates that a small amount of evaporation of the LLR 

may occur during summer. The δ18O values from the BLR 

are significantly heavier in the summer than winter, and 

some of the heavier δ18O values from the BLR plot along the 

lower extent of the Mud Lake evaporation line (fig. 11). This 

indicates that water in the BLR has undergone evaporation, 

and the positive correlation between δ18O values and discharge 

in the BLR below Mackay Reservoir (r=0.97) shows that the 

evaporation occurred to water stored in Mackay Reservoir. 

Two of the heavier δ18O values from the BLR also plot near 

the LMWL for winter, not the Mud Lake evaporation line, 

and these heavier values may be due to summer precipitation, 

not evaporation.

Heavier δ18O values occurred in Mud Lake during both 

summer and winter, and these heavier δ18O values plotted 

along the Mud Lake evaporation line (fig. 11), indicating that 

the heavier values were due to evaporation. Heavy δ18O values 

may occur during both summer and winter in Mud Lake 

because it is a shallow lake with a large surface area (area of 

about 4,000 acres and maximum storage of 61,000 acre-ft; 

Spinazola, 1994). In the heat of summer, the large surface 

area promotes significant evaporation of the lake, which 

enriches the δ18O values. During the cold winter months, the 

large surface area still promotes evaporation, although much 

less than in summer. However, this smaller amount of winter 

evaporation still enriches the δ18O values of the lake because 

of the much smaller volume of storage in the lake during 

winter (fig. 18B) and, because water from the lake is not being 

used for irrigation, the longer residence time of water in the 

lake during winter relative to summer.

Natural Groundwater

At wells located near or slightly downgradient of 

areas where episodic recharge of surface water occurs, 

water levels measured at the wells, as well as groundwater 

geochemistry, may rapidly respond to the episodic 

recharge. Thus, episodic recharge of surface water may 

produce patterns of peaks and valleys in time series plots 

of water levels and chemical concentrations. Because the 

surface-water recharge from streams is typically more dilute 

than the groundwater (table 12), chemical concentrations in 

groundwater decrease as water levels increase. Consequently, 

episodic recharge of surface water may produce an inverse 

correlation between rising and declining water levels 

and concentrations of major ions in a well (Bartholomay 

and others, 2012). At wells some distance from areas 

of episodic recharge of surface water, the groundwater 

containing the episodic recharge may not reach the well at 

all or may take several years or more to flow to the well. 

Under these conditions, there may be no inverse correlation 

between water levels and chemical concentrations, or the 

inverse correlation may be offset by a lag period that depends 

on the rates at which hydraulic pressure heads influence 

water levels in a well and the time it takes for groundwater 

containing the episodic recharge to reach the well.
62 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig18ab

δ18O in permil VSMOW

Date of sample collection and measurement of daily discharge

Daily discharge, in cubic feet per second

-15.00

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50,000

40,000

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January 1991 July 1991 January 1992 July 1992

January 1991 July 1991 January 1992 July 1992

Date of sample collection and measurement of daily storage

B

A

Discharge at BLR below Mackay Reservoir

Discharge at LLR below Wet Creek near Howe

(USGS site No. 13118700)

δ18O in Big Lost River below Mackay Reservoir

δ18O in Little Lost River near Howe

δ18O in Birch Creek at Blue Dome

Storage in Mud Lake

δ18O in Mud Lake near Terreton

EXPLANATION

EXPLANATION

Figure 18. Monthly stable isotope ratios of oxygen (δ18O) for surface water from the 

(A) Big Lost River (BLR), Little Lost River (LLR), Birch Creek, and Mud Lake and the daily 

discharge of the BLR and LLR and (B) storage of water in Mud Lake from January 1991 to 

July 1992, Idaho National Laboratory and vicinity, eastern Idaho.
Geochemistry of Surface Water and Groundwater 63

Episodic infiltration recharge from the BLR produces an 

extensive temporal influence on groundwater geochemistry at 

the INL because the BLR channel extends across the western 

part of the INL (fig. 3B), discharge of the BLR at the INL 

ranges from hundreds of cubic feet per second during wet 

climate cycles to zero during dry climate cycles23 (fig. 5), 

surface water may rapidly infiltrate to the aquifer (Nimmo and 

others, 2002), and the water in the BLR ranges from slightly 

to significantly more dilute than most groundwater in the 

western part of the INL (fig. 28B; Bartholomay and others, 

2012). The distribution and amount of water in the BLR at the 

INL affects the location and amount of infiltration recharge. 

For example, during 1965–87, 50 percent of the water in the 

BLR at the INL was diverted to the INL spreading areas, 

9 percent infiltrated between the INL diversion and Lincoln 

Boulevard (fig. 8B), and 41 percent either infiltrated below 

Lincoln Boulevard or flowed into playas 1, 2, or 3 (fig. 3B) 

(Bennett, 1990). Infiltration rates from the BLR channel were 

small (≤4 [ft3/s]/mi) at small discharge volumes (37–118 ft3/s 

at streamgage BLR near Arco); however, at a large discharge 

volume (372 ft3/s at streamgage BLR near Arco; May 6–8, 

1985) infiltration rates were about 1–9 (ft3/s)/mi from the 

BLR channel and 28 (ft3/s)/mi from the BLR sinks (Bennett, 

1990, fig. 12). Episodic infiltration recharge from the BLR 

caused generalized water level rises and declines of ±6–10 ft 

in the western part of the INL during the 1980s and 1990s 

(Ackerman and others, 2006, fig. 22).

The temporal variability of groundwater geochemistry 

at the INL was evaluated by plotting time series of water 

levels and chloride concentrations in selected wells distributed 

throughout the INL (figs. 19A–Q). Chloride concentrations 

were selected to represent changes in groundwater 

geochemistry because chloride was routinely sampled, is 

nonreactive in solution, and has smaller concentrations in 

surface water (1–5 mg/L) than in natural (4.9–66.6 mg/L) 

or contaminated (11.9–240 mg/L) groundwater (fig. 27O, 

table 13). In addition, time series of nitrate concentrations 

were plotted for wells where irrigation may influence 

groundwater geochemistry.

North INL Area

Water levels and chloride concentrations are plotted 

in figures 19A–C for three wells, P&W 2, ANP 6, and 

No Name 1, in or near the North INL Area. These wells had 

annual or more frequent measurements of water levels and 

chloride concentrations beginning in 1980, 1992, and 1991. 

P&W 2 and ANP 6 are located about 0.6 and 0.9 mi west 

of BC and No Name 1 is located about 0.8 mi southwest of 

playa 4 (figs. 3B and 9).

Water-level patterns at P&W 2, ANP 6, and No Name 1 

were similar and included annual water-level fluctuations of 

1–5 ft in response to seasonal recharge of streamflow, waterlevel fluctuations of 5–26 ft in response to wet and dry climate 

cycles (Ackerman and others, 2006), and a long-term steep 

decline in water levels of 33–35 ft between 1988 and 2014.

Chloride concentrations ranged from 5 to 25 mg/L at 

P&W 2, 11 to 21.8 mg/L at ANP 6, and 18 to 23 mg/L at 

No Name 1 (fig. 19A–C), and increased in the downgradient 

direction (that is, chloride concentrations at P&W 2 < ANP 6 

< No Name 1). Chloride concentrations at P&W 2 and 

ANP 6 had a pattern of peaks and valleys, which indicates 

that groundwater at this location may include episodic 

recharge of surface water associated with wet and dry 

climate cycles. The estimated age of the fraction of young 

water at P&W2 and ANP 6 were 4–16 and 20–30 years 

(Busenberg and others, 2001), respectively, indicating that 

peak chloride concentrations probably lag peak water levels. 

The smaller chloride concentrations probably occur from 

dilution of groundwater in response to greater amounts of 

recharge from BC during wet climate cycles, whereas the 

larger chloride concentrations probably reflect relatively 

undiluted groundwater (Bartholomay and others, 2012). 

The nearly uniform chloride concentrations at No Name 1 

indicated that the old groundwater (tritium concentration 

of 0.13±0.03 pCi/L; table 17) at this well does not include 

variable surface-water recharge (although groundwater at 

No Name 1 probably did include variable recharge from BC 

prior to construction of diversion channels in 1969).

Northeast INL Area

Water levels, chloride concentrations, and nitrate 

concentrations were plotted in figures 19D–F for three wells, 

USGS 26, USGS 31, and USGS 32, in the Northeast INL 

Area. These wells had annual or more frequent measurements 

of water levels and chloride concentrations beginning in 

199124. Site USGS 26 is about 2.8 mi east of BC and USGS 

31 and USGS 32 are about 11 mi southwest of Mud Lake 

(figs. 3B and 9).

Water-level patterns at USGS 26 were similar to the 

water-level patterns at P&W2, ANP 6, and No Name 1. 

Water-level patterns in USGS 31 and USGS 32 included 

annual water-level fluctuations of 1–6 ft because of 

groundwater pumping for irrigation (Young and Norvitch, 

1984) in the Mud Lake area, water-level fluctuations of 3–14 ft 

in response to wet and dry climate cycles, and a long-term 

decline in water levels of 18 and 24 ft between 1988 and 2014.

23For the purposes of this report, wet (and dry) climate cycles consisted of two or more consecutive years with more than (or less than) 25 ft3

/s discharge in the 

BLR below INL diversion near Arco Idaho (USGS site number 13132520). Based on figure 5, for the 50-year period of record between 1965 and 2012, each wet 

or dry climate cycle lasted from 4 to 12 years.

24Annual water-level measurements at some wells, such as USGS 26, began decades prior to beginning annual measurements of chloride concentrations.
64 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig19a-f

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1950195519601965197019751980198519901995200020052010201519501955196019651970197519801985199019952000200520102015

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Chloride and nitrate concentrations, in milligrams per liter (as N for nitrate)

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Water Level

Chloride

Nitrate

EXPLANATION

Figure 19. Water levels and chloride and nitrate concentrations for selected wells, Idaho National Laboratory and vicinity, 

eastern Idaho.
Geochemistry of Surface Water and Groundwater 65

tac18-1192_fig19g-l

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1950195519601965197019751980198519901995200020052010201519501955196019651970197519801985199019952000200520102015

Year

G. USGS 1 H. USGS 2

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Chloride and nitrate concentrations, in

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EXPLANATION

Figure 19.—Continued
66 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig19m-q

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19501955196019651970197519801985199019952000200520102015

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19501955196019651970197519801985199019952000200520102015

Year

N. USGS 19

P. USGS 57

M. USGS 12

O. USGS 9

Q. USGS 86

Chloride and nitrate concentrations, in

milligrams per liter (as N for nitrate)

305

315

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Chloride

Nitrate

EXPLANATION

Figure 19.—Continued
Geochemistry of Surface Water and Groundwater 67

Excluding one outlier chloride concentration25 (19.9 mg/L 

in 1999), chloride concentrations at USGS 26 ranged from 

11 to 15 mg/L. Like chloride concentrations at No Name 1, 

the chloride concentrations at USGS 26 were nearly uniform. 

Nitrate concentrations also were nearly uniform, and generally 

ranged between 0.73 and 0.97 mg/L as N. Consequently, 

groundwater at this well does not include episodic recharge 

of surface water, but probably does include a small amount of 

groundwater influenced by irrigation.

Chloride concentrations at USGS 31 ranged from 

10 to 31.8 mg/L and increased throughout the period of 

record (1953–2014). Nitrate concentrations also steadily 

increased (period of record 1984–2014), from 0.81 to 

1.14 mg/L as N. The absence of peaks and valleys in the 

chloride concentrations indicates that episodic recharge of 

surface water did not influence groundwater at this location, 

and the larger than background concentration of nitrate26

indicates that groundwater at this location includes a small 

amount of groundwater influenced by irrigation. The steadily 

increasing chloride and nitrate concentrations may result from 

anthropogenic influences (Bartholomay and others, 2012), 

such as application of agricultural products to the land coupled 

with recycling of groundwater used for irrigation (Plummer 

and others, 2000) and more efficient irrigation methods (that 

is, transitioning from flood to sprinkler irrigation), or a longterm trend of decreasing recharge.

Chloride and nitrate concentrations at USGS 32 ranged 

from 18 to 59.7 mg/L for chloride and 1.0 to 1.8 mg/L as N 

for nitrate. Measurements of chloride and nitrate were sparse 

prior to 1984, but concentrations of chloride and nitrate have 

a pattern of peaks and valleys between 1977 and 2003 that 

indicates that groundwater at this location includes episodic 

recharge of surface water associated with wet and dry climate 

cycles. In addition, the nitrate concentrations indicate that the 

groundwater was influenced by irrigation. USGS 32 is located 

near areas in the Mud Lake area that are irrigated with both 

surface water and groundwater, and the variability in chloride 

and nitrate concentrations at this well may reflect temporally 

changing relative amounts of surface water and groundwater 

used for irrigation in response to wet and dry climate cycles. 

The steadily increasing chloride and nitrate concentrations 

between 2003 and 2013 may be due to anthropogenic 

influences or declining recharge.

Southeast INL Area

Water levels and chloride concentrations were plotted 

in figures 19G–H for two wells, USGS 1 and USGS 2, in the 

Southeast INL Area. These wells had annual or more frequent 

measurements of water levels and chloride concentrations 

beginning in 1991. USGS 1 and USGS 2 are about 1.3 mi 

northeast of Atomic City and about 4.3 mi southwest of the 

MFC (figs. 3B and 9), respectively.

Water-level patterns at USGS 1 and USGS 2 were 

similar. They had annual water-level fluctuations of 1–2 ft 

due to groundwater pumping for irrigation (from areas to the 

northeast, east, and southeast; figs. 3B and 8B), water-level 

fluctuations of 4–11 ft in response to wet and dry climate 

cycles, and a long-term decline in water levels of nearly 

13–18 ft between 1984–85 and 2014.

Chloride concentrations at USGS 1 and USGS 2 

ranged from 9 to 14 and 8.8 to 20 mg/L, respectively, were 

nearly uniform at USGS 1, slightly increased from 1950 to 

1992 in USGS 2, and were nearly uniform in USGS 2 after 

1992. These slightly increasing or nearly uniform chloride 

concentrations indicate that groundwater at these wells does 

not include episodic recharge of surface water.

Central INL Area

Groundwater levels and chloride concentrations were 

plotted in figures 19I–K for three wells, USGS 17, USGS 18, 

and NPR Test, in the Central INL Area. These wells had 

annual or more frequent measurements of water levels and 

chloride concentrations beginning in 1989, 1992, and 1991. 

USGS 17 is located about 0.5 mi east of the BLR, USGS 18 is 

located about 3.1 mi south of playa 4, and NPR Test is located 

about 1.6 and 5.6 mi southeast of the BLR and NRF (figs. 3B

and 9), respectively.

Water-level patterns at USGS 17 and NPR Test were 

similar. They had annual water-level fluctuations of less than 

1 ft, water-level fluctuations of 4–16 ft in response to wet and 

dry climate cycles, and a long-term decline in water levels 

of 21–25 ft between 1987 and 2014. Water-level patterns in 

USGS 18 were similar to water-level patterns in the North 

INL Area.

Chloride concentrations ranged from 5.0 to 10 mg/L at 

USGS 17, 8.9 to 12.2 mg/L at USGS 18, and 9.4 to 22 mg/L at 

NPR Test. Chloride concentrations at USGS 17 and USGS 18 

were nearly uniform, indicating that groundwater at these 

wells may not include episodic recharge of surface water. 

25Outlier chloride concentrations may be due to dilution of groundwater with drilling fluids, accidental switching of water-quality sample bottles during 

sample processing (Rattray, 2012), or some unidentified cause (Rattray, 2014).

26The background concentration of nitrate was assumed to be equal to or less than 0.5 mg/L as nitrogen. This assumption was based on nitrate concentrations 

in BC valley groundwater, where irrigation did not influence the concentration of nitrate in groundwater.
68 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

However, the large changes in water levels in response to wet 

and dry climate cycles at USGS 17, plus the close proximity of 

this well to the BLR, indicates that groundwater at USGS 17 

was significantly influenced by episodic recharge from 

the BLR. Chloride concentrations at USGS 17 were nearly 

uniform because the water at this well, and thus the chloride, 

is derived primarily from the BLR. This interpretation is 

consistent with chloride concentrations at USGS 17 that were 

similar to chloride concentrations in the BLR (BLR near Arco, 

Idaho [13132500]); between 1965 and 2013, and based on 

94 chloride measurements, the BLR near Arco had a mean 

(plus or minus standard deviation) chloride concentration of 

5.9 ± 2.2 mg/L (data available at https://waterdata.usgs.gov/

nwis/inventory?agency_code=USGS&site_no=13132500).

Chloride concentrations at well NPR Test had a pattern 

of peaks and valleys (fig. 19K) during 1986–2001 and a slight 

increasing concentration trend from 2001 to 2014. The peaks 

and valleys indicate that groundwater at this site includes 

episodic recharge of surface water associated with wet and dry 

climate cycles, whereas the increasing trend may be due to the 

overall trend of decreasing recharge.

The peak chloride concentration at NPR Test, 22 mg/L, 

was much larger than the peak chloride concentration in 

groundwater from USGS 5 (13 mg/L in 1977; data available 

at http://maps.waterdata.usgs.gov/mapper/), the closest 

well north of NPR Test in a direction toward the BC valley. 

Consequently, a source for the larger chloride concentrations 

at well NPR Test may be episodic recharge from the BLR 

sinks that pushes irrigation- and wastewater-influenced 

groundwater near NRF, with large chloride concentrations, 

southeastward toward NPR Test. Comparison of peak water 

level and chloride concentrations suggests that there is about a 

5-year time lag for recharge from the BLR to reach NPR Test, 

which is consistent with the presence of young groundwater at 

NPR Test (based on a tritium concentration of 57.4±0.2 pCi/L; 

table 17). The interpretation was also consistent with nitrate 

concentrations that increased and decreased in unison with 

the chloride concentrations (fig. 19K) and with the orientation 

of contours of water-level changes resulting from episodic 

recharge from the BLR in response to wet climate cycles 

(Ackerman and others, 2006, fig. 22).

Northwest INL Area

Water levels, chloride concentrations, and nitrate 

concentrations were plotted in figures 19L–N for three wells, 

INEL 1 WS, USGS 12, and USGS 19, in the Northwest INL 

Area. These wells had annual or more frequent measurements 

of water levels and chloride concentrations beginning in 1984, 

1990, and 1980. INEL 1 WS and USGS 12 are about 2.6 and 

2.4 mi west of the BLR, respectively, and USGS 19 is about 

1.9 mi south of the LLR sinks (figs. 3B and 9).

Water-level patterns at INEL 1 WS and USGS 12 were 

similar. They had annual water-level fluctuations of less 

than 1 ft, water-level fluctuations of 6–20 ft in response to 

wet and dry climate cycles, and a long-term steep decline in 

water levels of 27–31 ft between 1987 and 2014. Water-level 

patterns in USGS 19 had annual water-level fluctuations 

ranging from 1 to 20 ft, water-level fluctuations of 6–13 ft 

in response to wet and dry climate cycles, and a long-term 

decline in water levels of 21 ft between 1984 and 2014. The 

wide range of annual water-level fluctuations in USGS 19 

probably was due to several surface water sources of recharge, 

such as infiltration recharge from the LLR channel and 

sinks and surface water used for irrigation, and groundwater 

pumping for irrigation in the Howe area of the LLR valley 

(fig. 3B) (Bartholomay and others, 2012; Bartholomay and 

Twining, 2015).

Chloride and nitrate concentrations ranged from 28.7 to 

145 mg/L (excluding two large concentration outliers of 

210 and 230 mg/L) and 1.4 to 5.9 mg/L as N at well INEL 

1 WS, 12 to 44 mg/L and 0.18 to 2.7 mg/L as N at USGS 12, 

and 8 to 28 mg/L (excluding a small concentration outlier of 

1 mg/L) and 0.64 to 1.5 mg/L as N at USGS 19. Patterns of 

chloride and nitrate concentrations at all three wells consisted 

of peaks and valleys, which indicates that groundwater at these 

wells includes episodic recharge of surface water associated 

with wet and dry climate cycles. The nitrate concentrations 

at all three wells shows that groundwater at these locations 

included groundwater from the LLR valley that was influenced 

by irrigation.

Water levels and chloride concentrations at USGS 12 

were inversely related (fig. 19M). This pattern suggests that 

recharge from the BLR during wet climate cycles was rapidly 

diluting chloride concentrations. This interpretation was 

consistent with the tritium concentration of 71.9±0.7 pCi/L 

at USGS 12 (table 17), which shows that this well contains 

very recent recharge from the BLR, perhaps within the past 

3–5 years (Busenberg and others, 2001; Bartholomay and 

others, 2012). Peak water levels and chloride concentrations at 

INEL 1 WS and USGS 19 are offset. This indicates that there 

is a time lag between when recharge occurred and when the 

recharge water reached these wells.

Southwest INL Area

Water levels and chloride concentrations were plotted 

in figures 19O–Q for three wells, USGS 9, USGS 57, and 

USGS 86, in the Southwest INL Area. These wells had annual 

or more frequent measurements of water levels and chloride 

concentrations beginning in 1979–80. USGS 9 is adjacent to 

INL spreading area C and about 3.2 mi southwest of RWMC, 

USGS 57 is about 0.8 and 0.3 mi south of the BLR and 

southwest of INTEC, respectively, and USGS 86 is about 

2.5 mi south of the BLR (figs. 3B and 9).

Water-level patterns at USGS 9 and USGS 86 were 

similar. They had annual water-level fluctuations of 1–7 ft, 

water-level fluctuations of 4–14 ft in response to wet and dry 

climate cycles, and a long-term steep decline in water levels 

of 20–21 ft between 1984 and 2014. The annual water-level 

fluctuations were due to the combination of infiltration 

recharge from the BLR channel at the INL and the use of both 

surface water and groundwater for irrigation in the BLR valley 

and on the ESRP near Arco (fig. 3B). Water-level patterns in 
Geochemical Implications for Hydrology 69

USGS 57 had annual water-level fluctuations of 1.5 ft or less, 

water-level fluctuations of 7–16 ft in response to wet and dry 

climate cycles (and diversions to the INL spreading areas), 

and a long-term decline in water levels of 19 ft between 1987 

and 2014.

Chloride concentrations ranged from 10 to 42 mg/L 

(excluding a concentration outlier of 4 mg/L) at USGS 9, 

16.3 to 200 mg/L at USGS 57, and 12 to 27 mg/L at 

USGS 86. Patterns of chloride concentrations at USGS 9 and 

USGS 57 consisted of peaks and valleys, which indicates 

that groundwater at these wells includes episodic recharge 

of surface water associated with wet and dry climate cycles. 

A pattern of peaks and valleys was present in chloride 

concentrations at USGS 86 between 1971 and 1992, but the 

nearly annual frequency of the peaks and valleys indicate 

that the chloride concentrations were probably not related to 

variable recharge associated with wet-dry climate cycles.

Water levels and chloride concentrations at USGS 9, 

after 1980, rise and fall nearly uniformly. This may be because 

episodic recharge from the BLR north of the RWMC pushes 

contaminated groundwater at the RWMC south toward 

USGS 9. An exception to the nearly uniform pattern of rising 

and falling water levels and chloride concentrations occurred 

during 1984–85, when enough water was diverted from the 

BLR to reach, and subsequently infiltrate from, INL spreading 

area C. This infiltrating water diluted chloride concentrations 

at USGS 9 during 1984–85.

Chloride concentrations at USGS 86 varied enough to 

suggest that some seasonal recharge, either from the BLR 

or irrigation return flows, influenced the geochemistry of 

groundwater at this well. At USGS 57, chloride concentrations 

were influenced by the amount of chloride discharged in 

wastewater at INTEC as well as from episodic recharge from 

the BLR. For example, the decrease in chloride concentrations 

during 1995 resulted from a decrease in chloride discharged 

at INTEC, and the decrease of chloride concentrations from 

2003 onward resulted from relocation in 2002 of the INTEC 

infiltration ponds to a location 1.4 mi west of USGS 57 (Davis 

and others, 2013).

Discussion

Temporally variable recharge from the BLR, LLR, BC, 

and of surface water used for irrigation produced temporal 

variability in the geochemistry of groundwater at the INL. 

The temporal variability of groundwater geochemistry due 

to variable recharge from the LLR, BC, and surface water 

irrigation was limited to small areas adjacent to these sources 

of recharge. In contrast, episodic recharge from the BLR 

produced temporally variable geochemistry across most of 

the western part of the INL. These results show that the ESRP 

aquifer is a mostly static system in the eastern part of the INL 

and largely a dynamic system in the western part of the INL.

Geochemical Implications for 

Hydrology

Sources of Recharge

Sources of recharge were identified at both large and 

small scales. At the large scale, groundwater at the INL was 

divided into areas where recharge from tributary water or 

regional groundwater primarily resides, and at the small scale, 

sources of recharge for specific Areas and wells at the INL 

were identified. Recharge that may have occurred during the 

last glacial epoch, or paleorecharge, may be present at seven 

wells in the southwestern part of the INL.

Tributary or Regional Water

Lithium concentrations of less than and greater than 

5 μg/L were previously used to divide the INL into areas 

that consisted primarily of tributary or regional groundwater 

(Ackerman and others, 2006; Fisher and others, 2012; 

Bartholomay and Hall, 2016). The spatial distribution of 

lithium, and silica concentrations (figs. 28L and R) were good 

indicators of where tributary water or regional groundwater 

reside in the aquifer because 

1. The chemistry of tributary water was influenced 

primarily by carbonate rocks (Carkeet and others, 2001; 

Swanson and others, 2002, 2003) and the chemistry 

of regional groundwater was influenced by carbonate 

and volcanic (rhyolite and basalt) rocks, (Rattray and 

Ginsbach, 2014; Rattray, 2015);

2. The abundance of lithium and silica in the carbonate 

rocks was either small or zero; 

3. Silica was present in abundance in volcanic rocks; and 

4. Lithium may substitute for aluminum in biotite (Deer 

and others, 1983), a mineral present in rhyolite (Rattray 

and Ginsbach, 2014). 

Therefore, regional groundwater should have larger lithium 

and silica concentrations than tributary water. Concentrations 

of lithium and silica were plotted on a graph (fig. 20)27 to 

evaluate whether lithium concentrations of 5 μg/L, or some 

other concentration, best differentiated areas where tributary 

valley water (groundwater and surface water) and regional 

groundwater reside in the shallow ESRP aquifer at the INL.

Increasing lithium concentrations (fig. 20) represent 

increasing dissolution of rhyolite and increasing silica 

concentrations represent increasing dissolution of basalt 

and (or) rhyolite. Surface water and groundwater from 

the tributary valleys, except groundwater from ML 55 (in 

the Beaverhead Mountains) and Kaufman Guard Station 

27Silica and lithium concentrations for contaminated groundwater were not plotted in figure 20, but contaminated groundwater had a maximum lithium 

concentration of 9 μg/L (table 14) which indicates that tributary water was the primary source of recharge at sites consisting of contaminated groundwater.
70 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig20

0

10

20

30

40

50

60

70

80

5 10 15 20 25 30 35 40 45 50

Silica, in milligrams per liter

ML 25

27

ML 29

117

W

Wheeler

ACW 4 Pancheri

19 99

23 22

126b RF

8

103 6

18

86 134

83 89

17

ANP 9

LR1

Area II 110A 1

AC 26 31 32

2

14

100 29

AT1

Mays

LLR

BC

ML 59

ML 58

ML 57

ML 55

McKinney

KGS

(62,12)

INEL-1 2,000 ft (60, 50)

ML 27

INEL-1 4,000 ft

(39, 280)

(Mann, 1986)

INEL-1 3,600 ft 

(33, 290)

(Mann, 1986)

Tributary water

Regional groundwater

Geothermal water

M2051

ANP6

BLR BLR

Hwy 3

ML

107

Coates

BLR

BLR

Lambert

Hill

119

NN1

LLR

P&W2 S17

102

11

S4 98

125 9

BFW

FS2

CC

ML 23

ML 30

ML 31

USGS 101

ML 22

Reno Ranch

ML 19

ML 24

ML 12

ML 6

ML 5 ML 17

Site 14

EBR 1

7

Lithium, in micrograms per liter

Increasing

dissolution of

basalt and (or)

rhyolite

Increasing

dissolution

of rhyolite

Dissolution of

carbonates 

Sources of solutes

Natural

groundwater

Surface water

Tributary valley groundwater

Regional groundwater

Regional with geothermal influence

Geothermal groundwater

Deep groundwater

North INL Area

Northeast INL Area

Southeast INL Area

Central INL Area

Northwest INL Area

Southwest INL Area

EXPLANATION

Figure 20. Concentrations of silica and lithium for surface water and groundwater, Idaho National Laboratory and 

vicinity, eastern Idaho.

(KGS), have concentrations of less than or equal to 6 μg/L 

for lithium and 21 mg/L for silica. Regional groundwater, 

except from ML 5 and ML 17 and wells with a geothermal 

influence (ML 25, ML 27, ML 29), has concentrations 

ranging from 12.4 to 32 μg/L for lithium and 27 to 41 mg/L 

for silica. The lithium and silica concentrations in some 

of the excepted wells were influenced by dissolution of 

rhyolite (ML 55, Kaufman Guard Station) or recharge in 

the northeastern Mud Lake area (ML 5 and ML 17) from 

carbonate rocks in the Beaverhead Mountains. Upwelling 

geothermal water rises through rhyolite basement rock 

underlying the thick accumulation of basalt on the ESRP so 

geothermal water (except for ML 58, which is geothermal 

water in the Beaverhead Mountains) and geothermally 

influenced groundwater (ML 25, ML 27, ML 29) have 

lithium concentrations exceeding those in most regional 

groundwater. Considering the lithium and silica concentrations 

representative of tributary water and regional groundwater, 

figure 20 indicates that there is a clear demarcation in 

these concentrations between natural groundwater at the 
Geochemical Implications for Hydrology 71

INL consisting primarily of tributary water or regional 

groundwater, with lithium and silica concentrations of less 

than or equal to 8 μg/L and 27 mg/L consisting primarily 

of tributary water and concentrations greater than or 

equal to 10 μg/L and 27 mg/L consisting primarily of 

regional groundwater.

Groundwater from five wells at the INL (USGS 103, 

USGS 124, USGS 126b, USGS 6, and USGS 18) that would 

be classified as regional groundwater using the 5 μg/L lithium 

division have lithium concentrations of more than 5 μg/L 

but less than 8 μg/L; this groundwater was reclassified as 

tributary water in this report (fig. 21). These slightly elevated 

lithium concentrations were due to (1) a mixture of mostly 

tributary water with a small amount of regional groundwater 

at USGS 103; (2) dissolution of rhyolite on or adjacent to 

the INL (figs. 4B and 21) at USGS 124 and USGS 126b; 

and (3) upwelling of geothermal water at or upgradient of 

USGS 6 and USGS 18 (figs. 9, 28A, K, and CC). Under the 

revised concentration ranges for tributary water and regional 

groundwater, shallow groundwater composed primarily of 

regional groundwater resided in the Northeast and Southeast 

INL Areas and shallow groundwater composed primarily of 

tributary water resided the North, Central, Northwest, and 

Southwest INL Areas.

Sources of Recharge at Specific 

Areas and Wells

Sources of recharge for specific Areas and wells at 

and near the INL were identified by evaluating all of the 

geochemical data previously presented. However, 87Sr/86Sr 

and 234U/238U ratios were particularly useful for identifying 

sources of recharge and mixing of water. These isotope ratios 

often provide unique fingerprints for different sources of water 

that were not dependent on elemental concentrations, and the 

unique fingerprints may be retained in the groundwater across 

significant distances of transport (Roback and others, 2001). 

These qualities of the isotope ratios make them useful for 

identifying sources of recharge and mixing of water far from 

their location of recharge. Consequently, sources of recharge 

at the INL were most easily identified by plotting 87Sr/86Sr 

and 234U/238U ratios for surface and groundwater samples on 

a graph and evaluating where the samples plot on the graph 

relative to binary mixing lines between various potential 

sources of recharge (figs. 22A–B) (Roback and others, 2001).

Binary mixing lines between different recharge 

sources (and basalt) at the INL were calculated (eq. 2-15) 

from strontium and uranium concentrations and isotope 

ratios (tables 14 and 16; Mann, 1986; Johnson and others, 

2000; Roback and others, 2001; McLing and others, 2002). 

Representative 87Sr/86Sr and 234U/238U ratios were available 

for recharge from regional groundwater (USGS 101), 

groundwater representative of surface water used for irrigation 

in the Mud Lake Area (ML 22), groundwater representative 

of water from the LLR (USGS 19) and BC valleys (P&W 2), 

the BLR (BLR near Atomic City), geothermal water (INEL-1 

10,300 ft), and deep groundwater in the central part of the 

INL (Site 14). Representative 87Sr/86Sr and 234U/238U ratios 

were not available for recharge from the LLR or groundwater 

from the BLR valley and Lost River Range. Representative 

87Sr/86Sr and 234U/238U ratios for basalt were used that were 

equal to the mean value for Cenozoic olivine basalts on the 

ESRP for 87Sr/86Sr (0.7069) and the 234U/238U activity ratio in 

groundwater from USGS 22 (1.54).28 Although binary mixing 

lines proved to be useful for identifying sources of recharge 

and mixing, 87Sr/86Sr and 234U/238U ratios for groundwater that 

consists of more than two sources of strontium and uranium, 

from recharge and dissolution of basalt, probably will not plot 

on a binary mixing line.

A second 234U/238U ratio from the BLR was available 

(BLR below INL diversion, table 16). This 234U/238U ratio 

(fig. 22A–B, 87Sr/86Sr ratio for the BLR near Atomic City) was 

smaller than the 234U/238U ratio for the BLR near Atomic City. 

These variable 234U/238U ratios probably result from temporally 

variable relative percentages of young surface water (that 

is, water from tributary creeks, overland flow, and direct 

precipitation) and older groundwater inflow that contribute 

to stream discharge, with the 234U/238U ratio decreasing as 

the percentage of young surface water increases. Both BLR 

samples were collected at flows well below peak spring runoff 

(U.S. Geological Survey, 2014); consequently, these samples 

of BLR water may represent a large amount of groundwater 

base flow. During peak spring runoff, a greater percentage of 

young surface water would contribute to stream discharge, 

resulting in 234U/238U ratios in the BLR that could be smaller 

than indicated on figures 22A–B. Because most recharge from 

the BLR at the INL occurs during spring runoff (Bennett, 

1990), much of the recharge at the INL from the BLR may 

have smaller 234U/238U ratios than indicated in figures 22A–B. 

The value for USGS 17 plots below values for the BLR 

in figure 22B and, due to its location adjacent to the BLR, 

probably consists primarily of recharge from the BLR. 

Consequently, a hypothetical binary mixing line between the 

BLR, as represented by USGS 17, and groundwater from the 

Little Lost River valley was shown on figure 22B.

28Roback and others (2001, fig. 3), in their binary mixing model for 87Sr/86Sr and 234U/238U in groundwater at the INL, used the same 87Sr/86Sr value for basalt, 

but used a value of 1 (secular equilibrium) for 234U/238U. In this report, the 234U/238U value from USGS 22, 1.54, was considered representative of the 234U/238U 

in groundwater from dissolution of basalt because the source of water at USGS 22 was precipitation, which means that all of the uranium in groundwater at 

USGS 22 was from dissolution of minerals in the host basalt.
72 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Roback and others (2001) plotted 87Sr/86Sr and 234U/238U 

ratios to evaluate sources and mixing of water at the INL. 

They determined that BC valley groundwater and regional 

groundwater mixed in the eastern part of the INL and that the 

BLR was an important source of recharge in the central and 

western parts of the INL. They also suggested that incongruent 

dissolution of basalt, accompanied by removal of uranium 

from solution through precipitation and (or) ion exchange, 

played an important role in modifying uranium concentrations 

and isotopic ratios in groundwater. Dissolution of basalt 

will alter some 87Sr/86Sr and 234U/238U ratios in groundwater 

(such that they plot to the left of their sources of recharge in 

figure 22A–B). However, significant dissolution of basalt, 

even of readily soluble basalt glass (Rattray and Ginsbach, 

2014), occurs only when water undersaturated with silica, 

such as tributary valley groundwater, infiltration of the BLR, 

and infiltration of precipitation, provides recharge to the 

ESRP aquifer. Significant dissolution of basalt, therefore, is 

not ubiquitous but is concentrated in areas where recharge 

that is undersaturated with silica occurs. Such recharge occurs 

as groundwater from the tributary valleys enters the ESRP 

aquifer at the mouths of the LLR and BC valleys, water from 

BC infiltrates through the BC channel, sinks, and playa 4, 

and water from the BLR infiltrates through the BLR channel, 

sinks, and playas and at the INL spreading areas.

North INL Area

Lithium and silica concentrations indicated that natural 

groundwater in the North INL Area consisted primarily of 

tributary water (figs. 20–21), with BC and groundwater from 

the BC valley as possible sources of recharge throughout the 

area and the BLR a possible source of water at playas 3 and 

4 (fig. 3B). Isotopic data were not available for ANP 8 and 

TDD 3, except for tritium activity at TDD 3, so the discussion 

of sources of recharge for this area was based primarily on 

data from ANP 6, No Name 1, IET 1 Disposal, and PSTF Test 

as well as P&W 2 from the mouth of the BC valley (fig. 21). 

The major ion chemistry of groundwater from ANP 8 and 

TDD 3 was similar to ANP 6 (table 13, figs. 28F–O), so these 

wells were presumed to have the same sources of recharge 

as ANP 6.

Light δ2H and δ18O values measured in groundwater from 

P&W 2 (-141.3 and -18.50 permil) and ANP 6 (-138.7 and 

-18.27 permil) were similar to values for BC or groundwater 

from the BC valley (fig. 11). P&W 2 had a small helium 

concentration, an Rs/Ra ratio of 0.99, and a Heterr value of 

5 percent (fig. 12), all of which suggest that this groundwater 

consisted largely of water from BC. ANP 6 had a slightly 

larger helium concentration, an Rs/Ra ratio of 1.16, and a 

Heterr value of 15 percent. ANP 6 is older and more evolved 

chemically than P&W 2, so these data were consistent with 

recharge from BC that has had a long enough groundwater 

residence time for some crustal helium and tritiogenic 3He to 

accumulate in the groundwater (fig. 12). Additionally, ANP 6 

plots along a binary mixing line for BC valley groundwater 

(P&W 2) and basalt, with the location of ANP 6 along the 

mixing line indicating that at least 10 percent of the strontium 

and uranium in the groundwater is from dissolution of basalt 

(fig. 22A). 

Heavy δ2H and δ18O values (-130.4 and -15.86 permil) 

were measured in groundwater from No Name 1 and indicated 

that groundwater at this well consisted mostly or entirely 

of evaporated surface water. No Name 1 is about 0.8 mi 

southwest of playa 4 (fig. 3B), which may receive water 

from either the BLR or BC, and one or both of these streams 

must be the source of evaporated water. An evaporation 

line projected backwards from No Name 1 in figure 11

indicated that this groundwater may originate from BC. 

However, the 87Sr/86Sr ratio at No Name 1 (0.71037) was 

similar to the ratio from the BLR (0.71056) but much smaller 

than the ratio from BC (0.71198). The Heterr value of this 

groundwater (10 percent) was consistent with recharge largely 

from the BLR or BC with a small amount of groundwater 

from the BC valley (fig. 14). However, because this was old 

groundwater (tritium activity of 0.13±0.03 pCi/L; fig. 13A) 

recharge consisting solely of surface water could have had a 

long enough groundwater residence time to accumulate some 

crustal and tritiogenic helium.

PSTF Test is located between playas 3 and 4 and 

IET 1 Disposal is located northeast of playa 4 (figs. 3B

and 9). The BLR occasionally flows into playas 3 and 4 

(Bennett, 1990), and BC occasionally flowed into playa 

4 prior to 1969, so either stream could be a source of 

recharge. However, the δ2H and δ18O values from PSTF 

Test (-133.4 and -17.64 permil) and IET 1 Disposal (-135.7 

and -17.58 permil) in figure 11 were consistent with either 

recharge from the BLR or a mixture of recharge from BC 

and the BLR. The Heterr values were 1 and 18 percent at 

PSTF Test and IET 1 Disposal (fig. 14), respectively. The 

small Heterr value at PSTF Test, plus the Rs/Ra ratio of 1.00, 

small helium concentration (fig. 12), and small tritium 

activity (2.5±0.1 pCi/L), indicated that this water probably 

consisted primarily of pre-1952 recharge of surface water. 

The larger Heterr value at IET 1 Disposal could indicate that 

this water contains some groundwater from the BC valley, 

but the small helium concentration at this well was similar to 

the small concentrations at ANP 6 and PSTF Test (fig. 28E) 

and indicated that this water also was recharged primarily by 

surface water.

Northeast INL Area

Lithium and silica concentrations indicated that the six 

natural groundwater samples from the Northeast INL Area 

consisted primarily of regional groundwater (figs. 20–21). 
Geochemical Implications for Hydrology 73

tac18-1192_fig21

9

8

7

6

5

2

1

99 98

97

90

89 87

86

85

83

82

65

57 36

32

31

29

27

26

24

23

22

20

19

18

17

15

14

12

11

3A

T3

T1

RP

N8 N9

N7 N6

125

124

120

116

115

109 108

107

105

104

103

102

101

100

M7S M3S

N13

FS2

BFW

126b

110A

P&W2

IET1

Highway 2

EBR1

CFA2

CFA1

ANP9

ANP8

ANP6

Site9

Site4

INEL1 WS

Site19

Site17

Site14

Area II

SE of AC

NPR Test

PSTF Test

No Name 1

Atomic City

Leo Rogers 1

Arbor Test 1

119 117

88

113 112

N12

N10N11

T2

TD

N2

KBF

134

135

Middle 2051

Highway 3

INEL1 10,300’ & 2,000’

Idaho National Laboratory

Regional groundwater Tributary

water

Big Lost River

Birch Creek

Little Lost River

Howe

Terreton

Monteview

Atomic City

Lost River Range

Lemhi Range

Li <8 μg/L

Li >10 μg/L

Li >5 μg/L

Lithium (Li) <5 μg/L

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30'

44°

00'

43°

45'

43°

30'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

Site14

CFA2

INEL1

Wells within spatially defined areas

North INL Area

Northeast INL Area

Southeast INL Area

Central INL Area

Northwest INL Area

Southwest INL Area

Contaminated groundwater

Deep groundwater

Geothermal water

Groundwater site

EXPLANATION

Figure 21. Wells within spatially defined areas and the division of tributary water and regional groundwater based on a 

5 microgram per liter (μg/L) lithium concentration (Ackerman and others, 2006; Fisher and others, 2012; Bartholomay and 

Hall, 2016) and lithium concentrations less than 8 μg/L and greater than 10 μg/L, Idaho National Laboratory and vicinity, 

eastern Idaho.
74 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig22a

1.50

1.75

2.00

2.25

2.50

2.75

3.00

3.25

0.7070 0.7080 0.7090 0.7100 0.7110 0.7120

BLR

ML 22

Area II

27

29

32

31

101

1

14

AT1

107

2

110A

100

ANP 6

18

Site 14

ANP 9

26

17 5

6

83

BFW

103

ESRP basalt

Surface water used for irrigation (southwest Mud Lake area)

Big

Lost

River

Deep ground - water

0.7056 to 0.7080, 1.54

Birch Creek valley groundwater

0.9

0.8

0.7

0.6

0.5

0.4

0.3 Mixing ratio

P&W2

BLR

Regional groundwater

0.2

0.1

EBR 1

15

Site 9

Binary mixing line

19

Little Lost River valley groundwater

INEL 1 10,300 ft

INEL 1 2,000 ft

Geothermal water

Isotope ratio of uranium-234/uranium-238 (234U/238U)

Isotope ratio of strontium-87/strontium-86 (87Sr/86Sr)

A

Birch Creek Valley groundwater and 

90:10 mixture of regional groundwater 

and surface water used for irrigation

Big Lost River

Birch Creek valley groundwater

Little Lost River valley groundwater

Regional groundwater

Geothermal water

Deep groundwater

North INL Area

Northeast INL Area

Southeast INL Area

Central INL Area

EXPLANATION

Figure 22. Strontium (

87Sr/86Sr) and uranium (234U/238U) isotope ratios in surface water and groundwater and binary 

mixing lines between various sources of recharge (and basalt), Idaho National Laboratory and vicinity, eastern Idaho. 

(A) 87Sr/86Sr and 234U/238U ratios for the North, Northeast, Southeast, and Central INL Areas. (B) 87Sr/86Sr and 234U/238U ratios 

for the North, Central, Northwest, and Southwest INL Areas.
Geochemical Implications for Hydrology 75

tac18-1192_fig22b

1.50

1.75

2.00

2.25

2.50

2.75

3.00

3.25

0.7070 0.7080 0.7090 0.7100 0.7110 0.7120

BLR

ANP 6

ESRP basalt

Big

Lost

River

0.7056 to 0.7080, 1.54

Birch Creek valley groundwater

0.9

0.8

0.7

0.6

0.5

0.4

0.3 Mixing ratio

P&W2

BLR

0.2

0.1

19 Site 17

22

12

89

Hwy 3

86 9

125

8 11

Binary mixing line

124

104

105

108

Little Lost River valley groundwater

Precipitation plus dissolution of basalt

18

BFW

17 5

83

6

103

EBR 1

Site 9

Site 14

15

109 0.7122, 2.31

Isotope ratio of uranium-234/uranium-238 (234U/238U)

Isotope ratio of strontium-87/strontium-86 (87Sr/86Sr)

B

Hypothetical mixing line between 

Little Lost River valley groundwater 

and the Big Lost River

Big Lost River

Birch Creek valley groundwater

Deep groundwater

North INL Area

Central INL Area

Northwest INL Area

Southwest INL Area

Contaminated groundwater (INTEC)

EXPLANATION

Figure 22.—Continued
76 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

However, both tributary water and regional groundwater could 

be sources of recharge to this area, with possible sources of 

recharge consisting of BC, groundwater from the BC valley, 

regional groundwater, surface water used for irrigation, and 

geothermal water.

The inference, based on lithium and silica concentrations, 

that groundwater in the Northeast INL Area consisted 

primarily of regional groundwater was only partially 

supported by binary mixing lines between regional 

groundwater and (1) surface water in the Mud Lake area used 

for irrigation or (2) groundwater from the BC valley (fig. 22A). 

The mixing lines indicated that groundwater from USGS 29 

was a mixture of about 90 percent regional groundwater 

and 10 percent surface water used for irrigation (plus some 

dissolution of basalt). Water from the other five wells was 

primarily a mixture of regional groundwater and water 

from the BC valley, with regional groundwater comprising 

about 10 percent of the groundwater at ANP 9, 40 percent at 

USGS 26, 70 percent at USGS 31, 80 percent at USGS 32, and 

90 percent at USGS 27.

Other evidence was available that supported the 

interpretations based on the mixing lines. For example, the 

helium concentration and ratio at USGS 29 indicated that 

this water was old groundwater with a significant amount 

of tritiogenic 3He (fig. 12) and the tritium activity indicated 

that this water was a mixture of young and old groundwater 

(fig. 13A–B). These data support the interpretation from 

the mixing lines that this groundwater was mostly regional 

groundwater with some recharge from surface water used for 

irrigation. Tritium activities at the other wells indicate that 

the water was old groundwater, consistent with the absence of 

surface water used for irrigation as a source of water at these 

wells. The δ2H and δ18O values also were lighter at ANP 9 than 

the other wells from the Northeast INL Area, consistent with 

larger percentages of tributary groundwater at ANP 9 and of 

regional groundwater at the other wells (fig. 28U).

The binary mixing lines (and δ2H and δ18O values for 

ANP 9) show that, in contrast to the interpretation based 

on lithium and silica concentrations, water from ANP 9 

and USGS 26 consisted primarily of tributary water. The 

helium concentration and ratio for ANP 9 (fig. 12) shows 

that this groundwater does not contain geothermal water, 

so the elevated lithium and silica concentrations at this well 

(10.2 μg/L and 30.6 mg/L, respectively; fig. 20) were probably 

due to mixing with regional groundwater containing large 

lithium concentrations or dissolution of rhyolite or rhyolitic 

debris originating from the southern extent of the Beaverhead 

Mountains (fig. 4A). The presence of some geothermal water 

at USGS 26, USGS 27, and USGS 31 was supported by the 

warm water temperatures (14.9–15.8 °C; figs. 27A and 28A), 

large helium concentrations (20.6–32.4 cm3 STP/g × 10-8; 

figs. 27G and 28E), large Rs/Ra ratio (9.70, for USGS 27; 

figs. 12 and 28Y), and large Heterr values (83–88 percent; 

figs. 14 and 28CC). The geothermal water represents 

upwelling of water from beneath the aquifer and indicates 

that some upward movement of water has occurred. The 

interpretation of upward flow was consistent with an 

intra‐borehole measurement of flow at USGS 31 and another 

well southeast of TAN (Ackerman and others, 2006). Although 

geothermal water in the Northeast INL Area could result 

directly from upwelling geothermal water, it also could result 

indirectly as geothermally influenced shallow groundwater 

from the Mud Lake area (Rattray, 2015) moves downgradient 

through the Northeast INL Area.

Southeast INL Area

The ten natural groundwater samples collected from the 

Southeast INL Area all had lithium and silica concentrations 

that indicated this groundwater consisted primarily of regional 

groundwater (figs. 20–21). There were many potential 

sources of recharge to this area, however, such as the BLR, 

BC, groundwater from the LLR and BC valleys, regional 

groundwater, and surface water used for irrigation.

Tritium activities of 10–19 pCi/L (fig. 13A–B) and nitrate 

concentrations of 0.9–1.5 mg/L as N (fig. 28N) indicate that 

all these waters were mixtures of young and old water and 

that they contain some recharge of surface water, groundwater 

influenced by irrigation, or both. The 87Sr/86Sr and 234U/238U 

ratios were measured for eight of the samples, which generally 

plot along a binary mixing line for BC valley groundwater 

and a 90:10 mixture of regional groundwater and surface 

water used for irrigation (fig. 22A). The mixing line indicates 

that BC valley groundwater comprises about 15–20 percent 

of groundwater at Arbor Test 1, USGS 2, and USGS 100, 

30 percent at USGS 1, 35–40 percent at Area II, USGS 14, and 

USGS 110A, and 45 percent at USGS 107.

Groundwater from USGS 107 and USGS 110A plots 

slightly below the mixing line for BC valley groundwater and 

the 90:10 mixture of regional groundwater and surface water, 

in a direction toward the 87Sr/86Sr and 234U/238U ratios for the 

BLR. These two wells plus groundwater from Leo Rogers 1 

and USGS 14, all located in the southwestern part of the 

Southeast INL Area ( ), had slightly heavier δ18O values than 

other groundwater from this Area, indicating that these four 

wells may contain a small amount of recharge from the BLR.
Geochemical Implications for Hydrology 77

Central INL Area

Lithium and silica concentrations for the eight natural 

groundwater samples from the Central INL Area indicated 

that these samples consisted primarily of tributary water 

(figs. 20–21). However, the locations of these samples 

extends about 24 mi in a northeast-to-southwest direction 

along the transition zone between tributary water and regional 

groundwater, so potential sources of recharge included 

the BLR, BC, groundwater from the LLR and BC valleys, 

regional groundwater, surface water used for irrigation in the 

Mud Lake area, and geothermal water. In addition, USGS 83 

may consist of paleorecharge (see section, “Paleorecharge”).

The 87Sr/86Sr and 234U/238U ratios indicated that 

groundwater from the Badging Facility Well was about a 

50:50 mixture of recharge from the BLR and groundwater 

from the BC valley and that groundwater from USGS 18 

consisted of about 40 percent deep groundwater similar in 

composition to Site 14 and 60 percent groundwater from 

the BC valley (fig. 22A). The deep groundwater at Site 14 

consisted primarily of groundwater from the BC valley 

(based on the location of Site 14 relative to the mouth of 

the BC valley; fig. 21) with some geothermal water (based 

on the warm water temperature of 16.3 °C and large helium 

concentration of 38.4 cm3 STP/g x 10-8; table 12), so USGS 18 

contained a small amount of geothermal water, but consisted 

primarily of groundwater from the BC valley.

The 87Sr/86Sr and 234U/238U ratios for USGS 5 and 

USGS 17 plot below the ratios for the BLR on figure 22A–B, 

indicating that the BLR may be the only source of recharge at 

these wells. However, the presence of Heterr values of 30 and 

27 percent (fig. 14) and δ18O values (-17.82 and -17.53 permil; 

fig. 28U) that were lighter than δ18O values for the BLR below 

lower Lincoln Blvd Br (-17.17 permil) shows that some 

tributary groundwater probably was present at USGS 5 and 

USGS 17. The tritium activity at USGS 5 (28.4±0.4 pCi/L; 

fig. 13B) indicated that this groundwater was a mixture of 

young and old water, and the warm temperature (14.9 °C; 

fig. 28A) and relatively light δ2H and δ18O values (-138.3 and 

-17.82 permil; fig. 11) in this water indicated that the BC 

valley was the source of old groundwater at this well. The 

large tritium activity at USGS 17 (50.0±0.5 pCi/L) suggests 

that this groundwater was entirely young water. However, 

this tritium activity could occur if some recharge from the 

BLR during the 1950s to 1960s, when the tritium activity 

in the BLR was very large, mixed with old groundwater. 

The relatively heavy δ2H and δ18O values (-135.7 and 

-17.53 permil; fig. 11) in water from USGS 17 were more 

consistent with the LLR valley than the BC valley, as the 

source of old groundwater at this well.

NPR Test was not analyzed for 87Sr/86Sr and 234U/238U 

ratios, but the large tritium activity (57.4±0.2 pCi/L), 

small Heterr value (8 percent), and helium concentration and 

Rs/Ra ratio (fig. 12) all indicated that the BLR is the primary 

source of recharge at this well. However, the δ2H and δ18O 

values (-137.6 and -17.76 permil) were lighter than values 

for the BLR below lower Lincoln Blvd Br., indicating that 

some tributary valley groundwater probably was present in 

this water. As described in section, “Temporally Variable 

Water Chemistry,” groundwater from the LLR valley may 

flow to NPR Test during periods of surface water recharge 

at the BLR sinks. The groundwater sample at NPR Test 

was collected in October 1996, and a significant amount of 

discharge in the BLR, and recharge to the BLR sinks, occurred 

at the INL during 1995–96 (fig. 5). In comparison to USGS 5, 

which received recharge of groundwater from the BC valley, 

groundwater from NPR Test was slightly cooler (12.2 °C; 

fig. 28A), had heavier δ2H and δ18O values, and had more 

dissolved ions (fig. 28B). This was consistent with (1) cooler 

groundwater upgradient of NPR Test compared to USGS 5 

(fig. 16), (2) heavier δ2H and δ18O values, and (3) due to 

agricultural activities, more dissolved ions in groundwater 

from the LLR valley compared to groundwater from the 

BC valley (fig. 28B). Based on this comparison and on the 

hydrologic conditions in 1995–96, some groundwater at 

NPR Test probably originated from the LLR valley.

USGS 6 and USGS 103 had lithium concentrations 

of 7.3 and 6.9 μg/L. These concentrations were slightly 

larger than other groundwater at the INL originating from 

the tributary valleys (fig. 20) because a small amount of 

geothermal water probably was present at USGS 6 and a 

small amount of regional groundwater probably mixed with 

tributary water at USGS 103. Groundwater from both wells 

have 87Sr/86Sr and 234U/238U ratios that plot near the mixing 

lines for the BLR and groundwater from the LLR valley 

(fig. 22B). Groundwater at USGS 6 had a small tritium 

activity (0.3±0.8 pCi/L), a warm temperature (14.1 °C), small 

nitrate concentration (0.3 mg/L as N), and a large Heterr value 

(62 percent), all of which indicate that this water originated 

north of USGS 6. However, the heavy δ2H and δ18O values 

(-135.2 and -17.62 permil) at USGS 6 indicated that the 

primary northern source of recharge to this old groundwater 

was the BLR at playas 3 and 4. At USGS 103, a Heterr value of 

16 percent and a tritium activity of 11.8±0.1 pCi/L indicated 

that the groundwater was composed of both young and 

old water, with the young water from the BLR and the old 

groundwater primarily from the LLR valley.
78 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Northwest INL Area

Lithium and silica concentrations for the 17 natural 

groundwater samples from the Northwest INL Area indicated 

that these samples consisted primarily of tributary water 

(figs. 20–21). Potential sources of recharge from tributary 

water in this area included the BLR, groundwater from the 

LLR valley and Lost River Range, and precipitation. The LLR 

is an important source of recharge to groundwater in the LLR 

valley, but because the terminus of the LLR is just north of the 

INL, the LLR provides only indirect recharge to the INL.

Because 87Sr/86Sr and 234U/238U ratios were analyzed only 

from four samples from the Northwest INL Area (fig. 22B), 

other geochemical data were required to identify the sources 

of recharge. The δ18O and δ13C values (fig. 23) were used to 

differentiate between the sources of recharge because δ18O 

values in the LLR, the BLR (below lower Lincoln Blvd. Br.), 

and groundwater from the LLR valley were intermediate to 

light, heavy, and light (tables 3 and 15, fig. 28U), respectively, 

and δ13C values for the same sources of recharge were heavy, 

light, and intermediate (fig. 28V). Tritium activities were a 

good indicator of young recharge in groundwater, with larger 

and smaller activities indicating greater and lesser amounts 

of young recharge from the BLR; tritium activities are shown 

in parentheses in figure 23. Additionally, groundwater that 

was heavily influenced by irrigation in the LLR valley, as 

indicated by nitrate concentrations greater than 1.0 mg/L 

as N, was detected in an area between the BLR and 2.5 mi 

west of the BLR, whereas groundwater with smaller nitrate 

concentrations, and apparently uninfluenced or lightly 

influenced by irrigation in the LLR valley, was detected in an 

area generally 3 or more miles west of the BLR (fig. 28N).

-14

-12

-10

-8

-6

-4

-18.5 -18.3 -18.1 -17.9 -17.7 -17.5 -17.3 -17.1

BLR BLR

LLR

LLR Mays

(0 ±13)

RF

(9.6 ±13)

22

(161)

Harrell

(35 ±13)

23

(1.3)

19

(11.8)

15

(1.8)

102

FS2 (71)

(37)

12

(72)

97

(69) 99

(36.2)

98

(20)

134 (17) and

Site 17 (32±13)

Site 19

(13)

Site 4 (52)

INEL 1 WS

(48)

Stable isotope ratio of oxygen (δ18O), in permil Vienna Standard Mean Ocean Water (VSMOW)

Stable isotope ratio of carbon (δ13C), in permil Vienna Pee Dee Belemnite (VPDB)

(72)

Big Lost River

Little Lost River

Little Lost River valley

Deep groundwater

Northwest INL Area

Tritium activity, in pCi/L

EXPLANATION

Figure 23. Stable isotope ratios of oxygen and carbon (δ18O and δ13C) for selected surface-water and groundwater sites, 

Idaho National Laboratory and vicinity, eastern Idaho.
Geochemical Implications for Hydrology 79

Groundwater from the Northwest INL Area, except 

USGS 22 and USGS 23, plots between or near data 

representing the BLR and groundwater from the LLR 

valley (fig. 23). USGS 22 had a small estimated hydraulic 

conductivity (0.68 ft/d; log K of <-0.17 ft/d; table 11), small 

DO, large sodium, potassium, and chloride concentrations, 

small bicarbonate and uranium concentrations, a distinctive 

hydrochemical facies (fig. 10B), a light δ13C value, a 234U/238U 

ratio approaching the value for basalt (fig. 22B), a large tritium 

activity (160.9±0.4 pCi/L; fig. 13A), and a small Heterr value 

(0 percent; fig. 28CC). All of these chemical characteristics 

were consistent with young water consisting of rapid, focused 

vertical recharge (fig. 14) from precipitation that dissolved 

evaporite (possibly road salt) and silicate minerals. Projecting 

the tritium activity at USGS 22 backward in time (fig. 13A) 

shows that the precipitation recharge occurred sometime 

between 1954 and 1981. USGS 23 had warm groundwater 

(15.4 °C; fig. 28A, table 12), a heavy δ13C value and, because 

it had a small tritium activity and a moderately large Heterr

value (1.3±0.1 pCi/L and 57 percent, respectively; fig. 14), 

consisted of old groundwater. However, the relatively small 

silica concentration (16.1 mg/L; fig. 28L and table 13) in this 

groundwater indicates that it has not had a long residence 

time in the ESRP aquifer. Based on these geochemical 

characteristics, and due to the close proximity of USGS 23 to 

the Lost River Range, groundwater from the Lost River Range 

was probably the primary source of water at USGS 23.

The δ18O, δ13C values, and tritium activities (fig. 23) 

indicated that (1) USGS 12, USGS 97, and USGS 102 

consisted largely of recharge from the BLR with some 

groundwater from the LLR valley; (2) Site 4 was a relatively 

even mixture of these two sources of water; (3) Fire Station 2, 

INEL 1 WS, and USGS 99 consisted largely of groundwater 

from the LLR valley with some recharge from the BLR; 

(4) Site 17, Site 19, USGS 98, and USGS 134 consisted 

largely of groundwater from the LLR valley; and (5) USGS 19 

consisted largely of groundwater from the LLR valley with 

some recharge from either the LLR, groundwater from the 

Lost River Range, or both. The 87Sr/86Sr and 234U/238U ratios 

for USGS 12 were consistent with groundwater consisting 

primarily of recharge from the BLR, but the ratios for Site 17 

indicate that there probably was another source of recharge at 

this well besides groundwater from the LLR valley (fig. 22B).

The only isotopic data available for NRF 2, NRF 7, 

and NRF 8 were tritium activities from NRF 7 and NRF 8. 

However, the major ion chemistry of NRF 2 and NRF 8 was 

similar to the chemistry of USGS 12 (table 13), indicating 

that these wells may have the same sources of recharge. 

Groundwater at NRF 7 was dilute (table 12; also, specific 

conductance ranged from 202 to 268 μS/cm at 25 °C from 

1991 to 2014; U.S. Geological Survey, 2014), and the only 

plausible sources of this dilute water were the BLR and 

precipitation. The tritium activity was 12.8±12.8 pCi/L at NRF 

7 in 1996 (table 17), but 35 low-level tritium analyses of less 

than 5 pCi/L from 1997–201529 (Bartholomay, Knobel, and 

others, 2000; Bartholomay and others, 2001; Bartholomay and 

others, 2002; U.S. Geological Survey, 2014) show that water 

at this well is old groundwater. Consequently, water at NRF 7 

probably consists mostly of old recharge from the BLR.

Southwest INL Area

Lithium and silica concentrations for the 11 natural 

groundwater samples from the Southwest INL Area indicated 

that these samples consisted primarily of tributary water 

(figs. 20–21). Potential sources of recharge from tributary 

water in this area included the BLR and groundwater from the 

BLR valley, LLR valley, and Lost River Range. Four of the 

groundwater samples, collected from USGS 86, USGS 89, 

USGS 117, and USGS 119, seemed to consist of paleorecharge 

(see section, “Paleorecharge”).

The 87Sr/86Sr and 234U/238U ratios were available for five 

groundwater samples (that were not paleorecharge) (fig. 22B). 

Five contaminated groundwater samples collected from 

wells in the Southwest INL Area (USGS 104, USGS 105, 

USGS 108, USGS 109, and USGS 124) had 87Sr/86Sr and 234U/238U ratios (fig. 22B), so these data also were used to 

identify sources of recharge to the Southwest INL Area. 

The contaminated groundwater samples were believed to 

have uncontaminated 87Sr/86Sr and 234U/238U ratios because 

(1) although 90Sr is discharged in wastewater at the INL, 

radioactive decay of 90Sr does not produce 87Sr or 86Sr as 

daughter products and (2) no anthropogenic or non-natural 

uranium isotopes were detected in the contaminated 

groundwater samples (Roback and others, 2001). However, 

USGS 109 had a large, unexplained 87Sr/86Sr ratio, and 

therefore was not used for identifying sources of recharge. 

Additionally, USGS 104 seemed to consist of paleorecharge 

and will be discussed in the section “Paleorecharge.”

29Three low-level tritium values measured in water from NRF 7 ranged from 23 to 57 pCi/L, but these measurements appear to be associated with analytical 

problems (Bartholomay, Knobel, and others, 2000; Bartholomay and others, 2001).
80 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Middle 2051 and Highway 3 are located near each other 

and the BLR (fig. 21). Middle 2051 had a large tritium activity 

(fig. 28BB) and heavy δ2H and δ18O values (fig. 11), consistent 

with recharge from the BLR. Ratios of 87Sr/86Sr and 234U/238U 

from Highway 3 indicated that this groundwater consisted 

primarily of water from the BLR (fig. 22B), and both these 

sites plot in the same area on a trilinear diagram as the BLR 

(fig. 10A). This evidence shows that groundwater at Middle 

2051 and Highway 3 consisted primarily of water from 

the BLR. 

The 87Sr/86Sr and 234U/238U ratios from USGS 9, 

USGS 105, USGS 108, and USGS 125 indicated that the 

BLR was the primary source of recharge at these wells with 

groundwater from the LLR valley a possible minor contributor 

of recharge (fig. 22B). Large tritium activities at USGS 9 and 

USGS 125 (fig. 28BB) support the interpretation that the BLR 

is the source of recharge, and δ2H and δ18O values for these 

four wells that were lighter than the δ2H and δ18O values for 

the BLR near Arco support the presence of some recharge 

from a source with lighter δ2H and δ18O values, such as 

groundwater from the LLR valley (fig. 28U).

The 87Sr/86Sr and 234U/238U ratios from USGS 124 

indicated that recharge at this well was about a 50:50 mixture 

of the BLR and groundwater from the LLR valley (fig. 22B). 

Slightly lighter δ2H and δ18O values at USGS 124 than at 

USGS 9 and USGS 125 (fig. 28U) support the interpretation 

that groundwater at USGS 124 consisted of a larger amount 

of groundwater recharge from the LLR valley than did 

groundwater at USGS 9 and USGS 125.

USGS 8, USGS 11, and USGS 135 are all located at 

or near the southwestern corner of the INL and extend in a 

northwest-to-southeast direction away from the mouth of the 

BLR valley (figs. 8A–B). The 87Sr/86Sr and 234U/238U ratios 

for USGS 8 and USGS 11 plot near, but slightly left of, the 

50:50 mixing point on the mixing line between the BLR and 

groundwater from the LLR valley (fig. 22B). Recharge of 

groundwater from the BLR valley or dissolution of basalt 

may cause these data points to plot slightly left of the mixing 

line. It is possible that groundwater from the BLR valley 

was a source of recharge to USGS 8, because USGS 8 is the 

closest well in the Southwest INL Area to the BLR valley. The 

closest well in the BLR valley to USGS 8 was the Arco City 

Well 4 (fig. 8A), which had a tritium activity of 83.8±2.9 pCi/L 

(fig. 28BB) and a δ18O value of -17.69 permil (fig. 28U). 

The tritium activity at USGS 8 (47.4±0.5 pCi/L) could be 

consistent with recharge from the BLR and groundwater from 

the BLR valley, but the δ18O value at USGS 8 (-17.78 permil) 

was much lighter than the δ18O value in the BLR near Arco 

(-17.4 permil) and indicated that USGS 8 was probably a 

mixture of recharge from the BLR and groundwater from the 

LLR valley. Tritium activities at USGS 135 and USGS 11 

were 14±1.9 and 31.8±0.2 pCi/L, respectively, and δ18O value 

for both wells was -17.92 permil. The slightly lighter δ18O 

values, relative to USGS 8, indicates that groundwater at these 

wells may consist of a larger amount of recharge from the 

LLR valley, and the larger tritium activity at USGS 11, relative 

to USGS 135, may be due to diversion of, and more recent 

recharge from, the BLR at the INL spreading areas (figs. 3B

and 5).

Comparison with Recharge Sources Simulated 

with a Groundwater-Flow Model

The sources of recharge at the INL are summarized in 

table 9 and figure 24A–B. The areas delineating recharge from 

specific source waters at the INL (fig. 24A–B), determined 

from geochemistry data, were compared to source water 

areas determined from backward particle tracking for model 

layer 1 of a three-dimensional, steady-state groundwater‐flow 

model (fig. 25; from Fisher and others, 2012, fig. 15A). The 

geochemistry data primarily represented conditions from 

1995–96, at the beginning of a wet period when the BLR 

flowed onto the INL (fig. 5), and the steady-state model 

represented 1980 conditions, at the end of a dry period when 

the BLR did not flow onto the INL. Thus, the hydrologic 

conditions should cause the areas delineating recharge 

from the BLR on figures 24–25 to differ, although the areas 

delineating other, more stable, sources of recharge should be 

similar for both 1980 and 1995–96 conditions.

Several differences were identified between source water 

areas determined from geochemistry and flow modeling. 

These differences included (1) recharge from BC near the 

north INL boundary in the flow model that was not supported 

by geochemistry, (2) groundwater from the BC valley in the 

flow model did not extend far enough south, (3) regional 

groundwater in the flow model that extended too far west 

in the southern part of the INL, (4) recharge in model layer 

1 from deeper groundwater or geothermal water was not 

represented in the flow model, and (5) recharge from the BLR 

in the southwestern part of the INL was not represented in the 

flow model.

Paleorecharge

The 87Sr/86Sr and 234U/238U ratios in groundwater 

from USGS 83, USGS 86, USGS 89, and USGS 104 

(contaminated groundwater), and EBR 1 (deep well), all 

located in the southwestern part of the INL, indicated 

that this groundwater consisted primarily of recharge 
Geochemical Implications for Hydrology 81

from the BLR, perhaps some groundwater from the LLR 

valley, and post-recharge dissolution of basalt (fig. 22B). 

The chemistry of groundwater from four of these wells 

(excludes USGS 104, which had some contamination from 

wastewater discharge), and USGS 117 and USGS 119, was 

slightly different from other groundwater in the southwestern 

part of the INL. For example, groundwater from these six 

wells, compared to nearby groundwater, generally had 

smaller specific conductance and concentrations of CO2, 

Ca, and HCO3 (figs. 28D, F, H) and larger concentrations of 

SiO2 (fig. 28L). The differences in concentrations at these 

wells were consistent with groundwater that had dissolved 

less carbonate rocks and more silicate rocks, which would 

occur if this groundwater, relative to surrounding groundwater, 

consisted of greater amounts of recharge from the BLR and 

lesser amounts of recharge of groundwater from the tributary 

valleys. The BLR also provided either all or nearly all of 

the recharge at two nearby wells, Highway 3 and Middle 

2051, but the chemistry of the groundwater at these wells 

was similar to most groundwater in the southwestern part of 

the INL. This suggests that the BLR must have been more 

dilute when providing recharge to the six wells with the 

different chemistry. The BLR was more dilute during spring 

runoff (see section, “Temporally Variable Water Chemistry”); 

consequently, the recharge from the BLR at the wells with 

different chemistry may have occurred during years with 

unusually large spring runoff. Alternatively, the dilute recharge 

could have occurred during wetter climatic conditions (Geslin 

and others, 2002) associated with the last glacial epoch.

Six of these wells have δ2H and δ18O values, and all six 

of the δ2H and δ18O values were much lighter (≤-138.9 and 

≤-18.05 permil) than the δ2H and δ18O values from the BLR 

on the ESRP (≥-135.0 and ≥-17.4 permil), although some δ2H 

and δ18O values from winter samples of the BLR collected 

in the BLR valley at higher altitudes were nearly as light as 

in groundwater from these wells (tables 3 and 15; figs. 11, 

15, and 18A). Considering that the BLR undergoes some 

evaporation, and that the higher altitude δ2H and δ18O values 

should become heavier as the BLR flows down valley and 

onto the ESRP during spring runoff, these higher altitude 

δ2H and δ18O values still do not explain the light δ2H and 

δ18O values in water collected from these six wells. The light 

δ2H and δ18O values in water from these wells may be due 

to recharge of paleowater (paleorecharge in fig. 24) during a 

colder, wetter period like the last glacial epoch. All seven of 

these wells are within, or adjacent to, the Big Lost Trough, 

an extensive depositional basin (Mark and Thackray, 2002), 

and their location in the southwestern extent of the Big Lost 

Trough (figs. 4B and 9) indicates that the BLR probably 

was a source of water at these wells. The Heterr values of 

27–40 percent (fig. 28CC) support the presence of some old 

water at these wells, as does the tritium activity at USGS 86 

(2.9±1.0 pCi/L). Large uncertainties associated with tritium 

activities in water from the other wells (and tritium from 

contamination at USGS 104) prevented determining if these 

wells consisted of old groundwater (table 17), although the 

uncertainties allow for the possibility that natural groundwater 

at each of these wells could be old groundwater. Age dating 

with low-level tritium, argon-39 (Hall and others, 2016), 

and carbon-14 could help determine if these wells contain 

old groundwater.

Paleorecharge currently may reside at these wells 

because of very slow travel times between current areas of 

recharge and the wells or, because rock units at these wells 

were largely impermeable, restricted horizontal groundwater 

flow to and from the wells. Considering the large range of 

hydraulic conductivities determined for the ESRP aquifer 

(0.01–24,000 ft/d; Ackerman and others, 2006), the hydraulic 

conductivities at these wells were either small (2.7–6.5 ft/d 

[log K of 0.43–0.81 ft/d] at EBR 1, USGS 83, and USGS 86) 

or very small (0.01–0.87 ft/d [log K of -2.00– -0.06 ft/d] at 

USGS 89, USGS 104, USGS 117, and USGS 119) (table 11; 

fig. 7). The very small hydraulic conductivities at wells 

USGS 89, USGS 117, and USGS 119 may be due to the close 

proximity of these wells to numerous volcanic vents. Areas 

near volcanic vents may contain dikes, alteration zones, and 

thick, tube-fed, pahoehoe flows, all of which may impede 

groundwater flow (Anderson and others, 1999). Regardless 

of the cause, wells with small hydraulic conductivities have 

restricted horizontal groundwater flow, and if horizontal flow 

was restricted then vertical flow, perhaps from ancient floods 

or meandering river courses of the BLR, may be the source of 

water at these wells.

The 87Sr/86Sr and 234U/238U ratios indicated that recharge 

from the BLR was the primary source of water at most of 

these wells (fig. 22B). Water at wells with small hydraulic 

conductivities either contained (USGS 86) or probably 

contained (EBR 1, USGS 83) some groundwater from the 

LLR valley (fig. 22B), and some recent recharge from the 

BLR at USGS 86 was indicated by the inverse relation at 

this well between water levels and chloride concentrations 

from 1975 to 1995 (fig. 19Q). The 87Sr/86Sr and 234U/238U 

ratios in groundwater from a well with a very small hydraulic 

conductivity (USGS 89) indicated that recharge from the BLR, 

and probably precipitation, were sources of water at this well; 

this also may be true for other wells (USGS 117, USGS 119) 

with very small hydraulic conductivities. USGS 104 also had 

a very small hydraulic conductivity; paleorecharge from the 

BLR may be the primary source of water at this well, but the 

presence of waste constituents discharged from INTEC at 

USGS 104 indicated that some recent recharge also is a source 

of water to this well.
82 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 9. Primary sources of recharge at groundwater sampling sites, Idaho National Laboratory and vicinity, eastern Idaho.

[Locations of sites shown in figures 8–9. Site name: Alternate names used in other reports shown in table 10. Source of recharge: Listed in order of probable 

largest contributing source to smallest contributing source. Abbreviations: INL, Idaho National Laboratory; sz, shallowest zone]

Site name Source of recharge

North INL Area

ANP 6 Birch Creek, Birch Creek valley groundwater

ANP 8 Birch Creek, Birch Creek valley groundwater

IET 1 Disposal Birch Creek and (or) Big Lost River, Birch Creek valley groundwater

No Name 1 Big Lost River, Birch Creek, Birch Creek valley groundwater

P&W 2 Birch Creek, Birch Creek valley groundwater

PSTF Test Big Lost River

TDD 3 Birch Creek, Birch Creek valley groundwater

Northeast INL Area

ANP 9 Birch Creek valley groundwater, regional groundwater

USGS 26 Birch Creek valley groundwater, regional groundwater, geothermal water

USGS 27 Regional groundwater, Birch Creek valley groundwater, geothermal water

USGS 29 Regional groundwater, surface water irrigation (Southwest Mud Lake Area, tables 10–11)

USGS 31 Regional groundwater, Birch Creek valley groundwater, geothermal water

USGS 32 Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area)

Southeast INL Area

Arbor Test 1 Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area)

Area II Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area)

Atomic City Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area)

Leo Rogers 1 Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area), 

Big Lost River

USGS 1 Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area)

USGS 2 Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area)

USGS 14 Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area), 

Little Lost River valley groundwater, Big Lost River

USGS 100 Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area)

USGS 107 Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area), 

Big Lost River

USGS 110A Regional groundwater, Birch Creek valley groundwater, surface water irrigation (Southwest Mud Lake Area), 

Big Lost River

Central INL Area

Badging Facility Well Big Lost River, Birch Creek valley groundwater

NPR Test Big Lost River, Little Lost River valley groundwater

USGS 5 Big Lost River (sinks and playas), Little Lost River valley groundwater

USGS 6 Big Lost River (playas 3 and 4), Little Lost River valley groundwater

USGS 17 Big Lost River, Little Lost River valley groundwater

USGS 18 Deep groundwater or geothermal water, Birch Creek valley groundwater

USGS 103 Big Lost River, Little Lost River valley groundwater, regional groundwater
Geochemical Implications for Hydrology 83

Table 9. Primary sources of recharge at groundwater sampling sites, Idaho National Laboratory and vicinity, eastern Idaho.—

Continued

Site name Source of recharge

Northwest INL Area—Continued

Fire Station 2 Little Lost River groundwater, Big Lost River

INEL 1 WS Little Lost River groundwater, Big Lost River

NRF 2 Big Lost River, Little Lost River valley groundwater

NRF 7 Big Lost River

NRF 8 Big Lost River, Little Lost River valley groundwater

Site 4 Little Lost River, Little Lost River valley groundwater, Big Lost River

Site 17 Little Lost River, Little Lost River valley groundwater

Site 19 Little Lost River, Little Lost River valley groundwater

USGS 12 Big Lost River, Little Lost River valley groundwater

USGS 19 Little Lost River valley groundwater, Little Lost River

USGS 22 Precipitation

USGS 23 Lost River Range groundwater

USGS 97 Big Lost River, Little Lost River valley groundwater

USGS 98 Little Lost River, Little Lost River valley groundwater

USGS 99 Little Lost River groundwater, Big Lost River

USGS 102 Big Lost River, Little Lost River valley groundwater

USGS 134 (sz) Little Lost River, Little Lost River valley groundwater

Southwest INL Area

Highway 3 Big Lost River

Middle 2051 (sz) Big Lost River

USGS 8 Little Lost River valley groundwater, Big Lost River, Big Lost River valley groundwater

USGS 9 Big Lost River, Little Lost River groundwater

USGS 11 Little Lost River groundwater, Big Lost River

USGS 105 Big Lost River, Little Lost River groundwater

USGS 108 Big Lost River, Little Lost River groundwater

USGS 124 Big Lost River, Little Lost River groundwater

USGS 125 Big Lost River, Little Lost River groundwater

USGS 135 (sz) Little Lost River groundwater, Big Lost River

Paleorecharge

EBR 1 Big Lost River, Little Lost River groundwater

USGS 83 Big Lost River, Little Lost River groundwater

USGS 86 Big Lost River, Little Lost River groundwater

USGS 89 Big Lost River

USGS 104 Big Lost River, Little Lost River groundwater, contaminated groundwater from INTEC

USGS 117 Big Lost River

USGS 119 Big Lost River
84 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig24a

Big Lost River

Birch Creek

Little Lost River

Howe

Terreton

Monteview

Atomic City

9

8

7

6

5

2

1

99

98

97

90

89 87

86

85

83

82

65

57 36

32

31

29

27

26

24

23

22

20

19

18

17

15

14

12

11

3A

T3

T1

RP

N9 N8

N6 N7

125

124

120

116

115

109 108

107

105

104

103

102

101

100

M7S M3S

N13

FS2

BFW

126b

110A

P&W2

IET1

Highway 2

EBR1

CFA2

CFA1

ANP9

ANP8

ANP6

Site9

Site4

INEL1 WS

Site19

Site17

Site14

Area II

SE of AC

NPR Test

PSTF Test

No Name 1

Atomic City

Leo Rogers 1

Arbor Test 1

119

117

88

113 112

N12

N10N11

T2

TD

N2

KBF

134

135

Middle 2051

Highway 3

INEL1 10,300’ & 2,000’

Regional

groundwater

Birch Creek valley

groundwater

Lost River Range

groundwater

Little Lost River

valley groundwater

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30'

44°

00'

43°

45'

43°

30'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

A

Geothermal water

Deep groundwater

Contaminated groundwater

Natural groundwater

Paleorecharge

Groundwater site

EXPLANATION

Site14

CFA2

INEL1

126b

119

Figure 24. Sources of recharge and mixing of water, Idaho National Laboratory and vicinity, eastern Idaho. (A) Recharge 

of regional groundwater, groundwater from the tributary valleys and the Lost River Range, and location of sites influenced 

by paleorecharge. (B) Recharge from streams and geothermal water.
Geochemical Implications for Hydrology 85

tac18-1192_fig24b

9

8

7

6

5

2

1

99 98

97

90

89 87

86

85

83

82

65

57 36

32

31

29

27

26

24

23

22

20

19

18

17

15

14

12

11

3A

T3

T1

RP

N8 N9

N6 N7

125

124

120

116

115

109 108

107

105

104

103

102

101

100

M7S M3S

N13

FS2

BFW

126b

110A

P&W2

IET1

Highway 2

EBR1

CFA2

CFA1

ANP9

ANP8

ANP6

Site9

Site4

INEL1 WS

Site19

Site17

Site14

Area II

SE of AC

NPR Test

PSTF Test

No Name 1

Atomic City

Leo Rogers 1

Arbor Test 1

119 117

88

113 112

N12

N10N11

T2

TD

N2

KBF

134

135

Middle 2051

Highway 3

ML 29

ML 27

Big Lost River

Birch Creek

Little Lost River

Howe

Terreton

Monteview

Atomic City

Birch Creek

infiltration

Geothermal

water

Big Lost River

infiltration Tributary groundwater

Regional groundwater

Zone of mixing

90:10 Regional:Tributary

INEL1 10,300’ & 2,000’

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30'

44°

00'

43°

45'

43°

30'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

B

Regional groundwater

Birch Creek valley groundwater

Little Lost River valley groundwater

Lost River Range groundwater

Birch Creek infiltration

Big Lost River infiltration

Geothermal water

Geothermal water

Deep groundwater

Contaminated groundwater

Natural groundwater

Paleorecharge

Groundwater site

EXPLANATION

Site14

CFA2

126b

119

INEL1

Recharge areas

Figure 24.—Continued
86 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig25

Mud

Lake

Birch

Camas

Creek

Little

Lost

River

Creek

Big

Lost

River

Snake

River

LOST RIVER RANGE

LEMHI RANGE

WHITE KNOB MTNS

PIONEER MTNS

EXPLANATION

Northwest mountain-front boundary source areas

Big Lost River valley (n = 1,199)

Little Lost River valley (n = 1,410)

Birch Creek valley (n = 200)

Northeast regional-underflow boundary source areas

Northeast boundary Reno section (n = 125)

Northeast boundary Monteview section (n = 188)

Northeast boundary Mud Lake section (n = 1,370)

Northeast boundary Terreton section (n = 1,734)

Streamflow infiltration source areas

Big Lost River stream reaches 600 and 601 (n = 15)

Big Lost River spreading area, stream reaches 602 and 605 (n = 0)

Big Lost River stream reaches 606 and 607 (n = 302)

Big Lost River sinks and playas, stream reaches 608 and 610 (n = 461)

Little Lost River stream reach 611 (n = 0)

Birch Creek stream reach 612 (n = 270)

Model area boundary

5-microgram-per-liter lithium 

concentration isopleth—Applies only to 

the upper 200 feet of the aquifer

5 

Major simulated interface between types A and B 

water

Particles starting location and source area in model layer 1—layer is about 100 feet thick, varying with the 

water-table altitude. n is the number of particles that terminate in a designated source area.

Orphans

Particles that did not terminate in one of the specified source areas (n = 426)

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Albers Equal-Area Conic projection, standard parallels 42°50’N, 44°10’N; 

central meridian 113°00’W; North American Datum of 1927.

Idaho National Laboratory

5

0 10 20 MILES

0 10 20 KILOMETERS

113°30 ́ 113°15 ́ 113° 112°45 ́ 112°30 ́ 112°15 ́

43°

15’ 

44°

43°

30’ 

43°

45’

Figure 25. Backward particle tracking starting locations and source water areas for particles released in model 

layer 1, Idaho National Laboratory and vicinity, eastern Idaho.
Geochemical Implications for Hydrology 87

Mixing of Water

A mixing zone between tributary water and regional 

groundwater, delineated by two dashed lines in figure 24B, 

was present in the eastern and southeastern parts of the INL. 

One line separated areas at the INL that were dominantly 

tributary water or regional groundwater and the second line 

delineated the approximate location where a mixture of 

90 percent regional groundwater and 10 percent tributary 

water occurred. The nearly uniform lithium concentrations 

in the area with dominantly tributary water (figs. 24A and 

28R) indicated that this area consisted almost entirely of 

tributary water, which means that the line dividing tributary 

water and regional groundwater divided an area where 

mixing of tributary water and regional groundwater does 

not occur (tributary water) from an area where mixing does 

occur (regional groundwater). The 90:10 mixture ratio for 

tributary water and regional groundwater was approximated 

from mixing ratios shown in figure 22A. The zone of mixing 

extends in a northeast-to-southwest direction from the eastern 

boundary of the INL near USGS 27 to south of the southern 

boundary of the INL and Atomic City, and the width of the 

zone extends about 3 mi near USGS 31 to about 9 mi at the 

southern boundary of the INL.

Geothermal water was present in regional groundwater 

and groundwater from the BC valley along the northeastern 

boundary of the INL, in the Northeast INL Area, and in the 

northern part of the Central INL Area (fig. 24B). The area 

delineating geothermal water includes deep groundwater at 

USGS 7 that contained some geothermal water and wells 

ML 27 and ML 29 that are outside, but adjacent to, the INL 

because they were previously shown to be influenced by 

geothermal water (Rattray, 2015). The geothermal water 

probably moved upward from below the aquifer with a 

chemical composition similar to INEL 1 10,300 ft, an 

interpretation consistent with geochemical modeling by 

Rattray (2015) for groundwater from ML 27 and ML 29.

The upwelling geothermal water probably was facilitated 

by volcanic vent corridors and (or) volcanic rift zones (fig. 4B) 

that are present in the northeastern part of the INL and the 

Mud Lake area (Anderson and others, 1999; Rattray, 2015). 

The upward moving geothermal water and volcanic structures 

may produce geologic controls on hydraulic conductivity, 

such as alteration zones, dikes, and thick, tube-fed, pahoehoe 

flows that impede the horizontal movement of groundwater 

(Anderson and others, 1999). Restricted horizontal flow 

in this area, from either alteration zones, dikes, thick, 

tube‐fed, pahoehoe flows, or perhaps fine-grained lacustrine 

sediment (fig. 4B), could explain why geochemistry data 

indicated that only small amounts of irrigation-influenced 

groundwater flowed into the INL from the Mud Lake area, 

across the northeastern INL boundary, even though the steep 

hydraulic gradient along this boundary (fig. 6) indicated that 

groundwater from the Mud Lake area should flow westerly 

into the INL.

Water from the BC channel, sinks, and playa 4 mixed 

with groundwater from the BC valley in the North INL 

Area. Tritium activities in groundwater from ANP 6 and 

No Name 1 (fig. 28BB) indicated that the groundwater was 

old, so infiltration and mixing of BC from the BC channel, 

sinks, and playa 4 probably had not occurred since 1969 when 

construction of diversion channels diverted most water from 

BC north of the INL.

The BLR flowed onto the INL during wet climate cycles, 

which included the mid-1990s (fig. 5), and recharge at the INL 

from the BLR during the mid-1990s occurred from the BLR 

channel, sinks, playas, and INL spreading areas. Recharge 

from the BLR was present in groundwater for a distance of 

about 37 mi in a north-to-south direction between playa 4 

and USGS 14, with a width of about 7–8 mi in the Central 

and Northwest INL Areas, and recharge from the BLR was 

present in groundwater throughout the Southwest INL Area. 

Recharge from the BLR mixed with regional groundwater and 

groundwater from the BC and LLR valleys (fig. 24B).

Groundwater Flow Directions

Areas indicating groundwater sources of recharge at 

the INL and water-table contours for April through mid-July 

199530 are shown in figure 26. Arrows were drawn through 

the center of the areas representing groundwater sources of 

recharge from the LLR and BC valleys and approximately 

parallel to the line separating tributary water from regional 

groundwater and the line indicating a 90:10 mixture ratio of 

tributary water and regional groundwater. All these arrows 

are approximately perpendicular to water-table contours. 

This result provided confidence that the areas delineating 

groundwater sources of recharge were accurate because it 

showed that groundwater flow directions estimated from 

geochemistry data were consistent with groundwater flow 

directions estimated from potentiometric measurements.

The areas delineating groundwater sources of recharge 

indicated that groundwater from the LLR and BC valleys 

initially flows southeasterly onto the ERSP aquifer at the 

INL, generally following the alignment of their valleys, 

but eventually begins to flow southwesterly in a direction 

paralleling the general flow direction of regional groundwater 

(fig. 26). Regional groundwater seems to flow southerly in 

the northeastern part of the INL and then flows southwesterly 

through the southeastern part of the INL.

30The water-table contours for 1989 (fig. 6) were not used in figure 26 because most geochemistry data used to draw groundwater source areas were from the 

mid-1990s. The 1995 contours were constructed from 139 water-level measurements (U.S. Geological Survey, 2014) using the same procedures (described in 

section, “Groundwater”) for constructing the 1989 water table contours.
88 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig26

Idaho National Laboratory

Tributary groundwater

Regional groundwater

90:10 Regional:Tributary

Groundwater flow direction

?

?

?

4,530

4,520

4,540

4,490

4,510

4,550

4,500

4,560

4,570

4,480

4,470

4,460

4,450

4,440

4,580

4,430

4,420

4,600

4,620

4,640

4,660

4,680

4,410

4,700

4,400

4,580

4,640

4,600

4,620

4,390

4,660

Birch Creek

Little Lost River

Big Lost River

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°0' 112°45' 112°30'

44°

00'

43°

45'

43°

30'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N.

4,600

?

Regional groundwater

Birch Creek valley groundwater

Little Lost River valley groundwater

Lost River Range groundwater

Water-level contour—Shows altitude of 

groundwater, 1995. Datum is NGVD 29. 

Contour intervals are 10 or 20 feet.

Water level uncertain

Well with water-level measurement

EXPLANATION

Figure 26. Areas of recharge from tributary valley and regional groundwater, approximate location of 

groundwater that is a 90:10 mixture of regional groundwater and tributary valley groundwater, water-table contours 

for spring 1995, and approximate groundwater flow directions, Idaho National Laboratory and vicinity, eastern 

Idaho.
Summary and Conclusions 89

Flow directions in the northern part of the INL were 

uncertain because the limited spatial representation of 

water-level measurements in this area meant that the 

water-table contours were either non-existent or imprecise. 

Water-table contours also indicated that water from USGS 8, 

just west of the western INL boundary, primarily was from 

either the BLR valley or the Lost River Range, whereas 

the geochemistry data were interpreted as indicating that 

groundwater at USGS 8 was primarily from the LLR valley. 

The few water-level measurements from this area make the 

water-table contours uncertain, and because representative 

87Sr/86Sr and 234U/238U ratios were not available for 

groundwater from the BLR valley and the Lost River Range 

the source of water at USGS 8 determined from geochemistry 

data was also uncertain.

Summary and Conclusions

Groundwater sources of recharge to the ERSP aquifer 

at the Idaho National Laboratory (INL) included regional 

groundwater in the eastern and southeastern parts of the 

INL, groundwater from the Birch Creek (BC) valley in the 

northern and central parts of the INL, groundwater from the 

Little Lost River (LLR) valley over most of the western part 

of the INL, groundwater from the Lost River Range along the 

southern part of the northwestern INL boundary, and upward 

moving geothermal water in the northeastern part of the INL. 

Groundwater from the Big Lost River (BLR) valley does not 

appear to contribute any recharge to the INL. Surface water 

sources of recharge included BC in the northern part of the 

INL and the BLR over most of the western part of the INL. 

Paleorecharge from the BLR may have been present at seven 

wells in the southwestern part of the INL.

Mixing of water occurred throughout the INL. In the 

western part of the INL, which was a dynamic hydrologic 

system because of episodic recharge from the BLR, the BLR 

mixed with tributary valley groundwater. In the eastern part 

of the INL, which was a relatively static hydrologic system, 

surface water from BC mixed with groundwater from the 

BC valley in the northern part of the INL, geothermal water 

mixed with tributary valley and regional groundwater in the 

northeastern part of the INL, and tributary valley and regional 

groundwater mixed in the southeastern part of the INL.

Groundwater flow directions were estimated from areas 

representing recharge of groundwater from the tributary 

valleys, the line indicating a transition between dominantly 

tributary water and regional groundwater, and a line 

representing a 90:10 mixing ratio of regional groundwater to 

tributary water. Flow directions for regional groundwater were 

southwesterly, and flow directions for tributary groundwater 

were southeasterly upon entering the eastern Snake River 

Plain aquifer, in alignment with the tributary valleys, but 

eventually became southwesterly in a direction parallel 

with regional groundwater. These estimated flow directions 

were generally perpendicular to water-table contours, 

which indicated that the estimated flow directions were 

reasonably accurate.

Several discrepancies were identified from comparison 

of sources of recharge determined from geochemistry data 

and from backward particle tracking with a groundwater-flow 

model. Some discrepancies, described for the particle tracking 

results, were representation of recharge from BC near the 

north INL boundary, groundwater from the BC valley not 

extending far enough south, regional groundwater that extends 

too far west in the southern part of the INL, and recharge from 

the BLR not represented in the southwestern part of the INL. 

The particle tracking results also do not represent recharge 

from geothermal water in model layer 1.

Evaluation of sources of recharge, mixing of water, and 

groundwater flow directions at the INL could be improved by 

collecting some additional data. For example, the definition 

of the water table was poor in the northern part and west 

of the INL, leading to uncertainty about flow directions in 

the northern INL and sources of recharge at USGS 8 west 

of the INL. Collection of spatially distributed water-level 

measurements in these areas could provide information that 

would reduce these uncertainties. Helium concentrations and 

ratios were important data for identifying geothermal water, 

but helium ratios were available for only a few groundwater 

samples from the northeastern part of the INL. Collection of 

helium ratios from more wells in this area would provide a 

more accurate resolution of the spatial extent of geothermally 

influenced water at the INL.

Ratios of strontium and uranium (87Sr/86Sr and 234U/238U) 

provided the best information for identifying sources of 

recharge and mixing of water at the INL. However, these ratios 

were not available for some potential sources of recharge, such 

as BC, the LLR, the BLR during peak runoff, and groundwater 

from the BLR valley and the Lost River Range. Collection of 

87Sr/86Sr and 234U/238U ratios for these potential source waters 

would improve confidence in geochemical interpretations 

of sources of recharge and mixing of water. Paleorecharge 

also may be present at some wells in the southwestern part of 

the INL; however, only one water sample from these wells 

had a measurement of age with enough accuracy to identify 

it as old water. Age dating, with low-level tritium, argon39, and carbon-14, of groundwater from the other wells 

possibly containing paleorecharge could determine whether 

groundwater at these wells is old groundwater.
90 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Acknowledgments

The author thanks Pete McMahon and Brian Marshall of 

the U.S. Geological Survey for providing technical reviews 

that significantly improved this manuscript.

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Figures 27–28 101

Figures 27–28
102 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig27a-e

GTW

27.8 to

57 oC

A B

C D

E

Temperature, in degrees Celsius

20

18

16

14

12

10

8

6

Dissolved oxygen, in milligrams per liter

14

12

10

8

6

4

2

0

pH

8.6

8.4

8.2

8.0

7.8

7.6

7.4

7.2

7.0

Specific conductance, in microsiemens

per centimeter at 25 degrees Celsius

1,200

1,000

800

600

400

200

0

Alkalinity, in milligrams per liter as calcium carbonate

400

350

300

250

200

150

100

50

NRF 6

1,480 μS/cm INEL-1 10,300 feet 1,878 μS/cm INEL-1 10,300 feet

740 mg/L as CaCO3

Surface water (SW)

Tributary valley groundwater (TGV)

Regional groundwater (RG)

Geothermal water (GTW)

Deep groundwater (DG)

Contaminated groundwater (CG)

North INL Area (N INL)

Northeast INL Area (NE INL)

Southeast INL Area (SE INL)

Central INL Area (C INL)

Northwest INL Area (NW INL)

Southwest INL Area (SW INL)

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

EXPLANATION

Natural groundwater 

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

Outlier

Outlier

75th percentile

Maximum (excluding outliers)

Minimum (excluding outliers)

50th percentile

(median)

25th percentile

Interquartile

range 

Figure 27. Statistical distribution of chemical and isotopic constituents in surface water and groundwater, Idaho National 

Laboratory and vicinity, eastern Idaho.
Figures 27–28 103

tac18-1192_fig27f-k

F G

H I

J

Carbon dioxide, as log PCO2 -1.5

-2.0

-2.5

-3.0

-3.5

Bicarbonate, in milligrams per liter

450

400

350

300

250

200

150

100

50

Sodium, in milligrams per liter

180

160

140

120

100

80

60

40

20

0

Helium, in cubic centimeters (at standard

temperature and pressure) per gram x 10-8

45

40

35

30

25

20

15

10

5

0

Calcium, in milligrams per liter

140

120

100

80

60

40

20

0

Magnesium, in milligrams per liter

45

40

35

30

25

20

15

10

5

0

K

ML 57

120 cm3 at STP/g x 10-8

USGS 7

149 cm3 at STP/g x 10-8

GTW

INEL-1 10,300 feet

900 mg/L 

INEL-1 10,300 feet

390 mg/L

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

Figure 27.—Continued
104 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig27l-q

L M

N O

P

Potassium, in milligrams per liter

14

12

10

8

6

4

2

0

Nitrate, in milligrams per liter as nitrogen (N)

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

Sulfate, in milligrams per liter

200

180

160

140

120

100

80

60

40

20

0

Fluoride, in milligrams per liter

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

Silica, in milligrams per liter

70

60

50

40

30

20

10

0

Chloride, in milligrams per liter

180

160

140

120

100

80

60

40

20

0

Q

INEL-1 10,300 feet; 13 mg/L

ML 57; 7.0 mg/L

NRF 6; 240 mg/L

USGS 113; 218 mg/L

ML 30

8.5 mg/L as N

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

Figure 27.—Continued
Figures 27–28 105

tac18-1192_fig27r-w

R S

T U

V

Aluminum, in micrograms per liter

60

50

40

30

20

10

0

Iron, in micrograms per liter

350

300

250

200

150

100

50

0

Lithium, in micrograms per liter

120

100

80

60

40

20

0

Barium, in micrograms per liter

300

250

200

150

100

50

0

Boron, in micrograms per liter

120

100

80

60

40

20

0

Chromium, in micrograms per liter

50

45

40

35

30

25

20

15

10

5

0

W

NRF 13; 1,400 μg/L

NRF 10; 1,000 μg/L

NRF 7

70 μg/L

BLR blw LLBB;

116 μg/L

USGS 113

342 μg/L 

INEL-1 2,000 feet; 900 μg/L

INEL-1 10,300 feet; 560 μg/L

USGS 65

190 μg/L

NRF 10; 1,700 μg/L

NRF 13; 1,300 μg/L

TAN Disposal; 410 μg/L

INEL-1

10,300 feet

1,100 μg/L Wildhorse Guard

Station; 655 μg/L

INEL-1 3,559-4,878 feet

280 μg/L

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

Figure 27.—Continued
106 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig27x-cc

X Y

Z AA

BB

Manganese, in micrograms per liter

50

45

40

35

30

25

20

15

10

5

0

Stable isotope ratio of oxygen (δ18O), in permil (‰)-15.0

-15.5

-16.0

-16.5

-17.0

-17.5

-18.0

-18.5

-19.0

Stable isotope ratio of carbon (δ13C), in permil

-2

-4

-6

-8

-10

-12

-14

-16

Strontium, in micrograms per liter

1,000

900

800

700

600

500

400

300

200

100

0

Uranium, in micrograms per liter

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

Stable isotope ratio of hydrogen (δ2H), in permil-120

-125

-130

-135

-140

-145

CC

Hwy 2; 100 μg/L

ML 25; 91 μg/L RWMC Prod

130 μg/L

TAN Disp 84 μg/L

IET-1 Disposal

140 μg/L

ML 22; -14.84‰

ML 19; -14.88‰

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

Figure 27.—Continued
Figures 27–28 107

tac18-1192_fig27dd-hh

DD EE

FF GG

HH

Stable isotope ratio of sulfur (δ34S), in permil

16

14

12

1086420

Radioisotope ratios of uranium (234U/238U)

3.2

3.0

2.8

2.6

2.4

2.2

2.0

1.8

1.6

1.4

Stable isotope ratio of nitrogen (δ15N), in permil

10987654

Isotope ratio of helium in environmental sample

divided by isotope ratio of helium in air (Rs/Ra)

6543210

Stable isotope ratio of strontium (87Sr/86Sr)

0.7130

0.7125

0.7120

0.7115

0.7110

0.7105

0.7100

0.7095

0.7090

No

GTW 

No

DGW 

SW

estimate 

USGS 124

7.46

USGS27

9.70 ML 58

0.71434

No

GTW 

No

SW 

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

Figure 27.—Continued
108 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig27ii-ll

JJ

KK LL Terrigenic helium, in percent

100

90

80

70

60

50

40

30

20

10

0

Estimated age of young fraction of groundwater,

in years before sampling date

60

50

40

30

20

10

0

Carbon-14, in percent modern carbon

90

80

70

60

50

40

30

20

SW estimate

No

SW 

No

GTW 

Estimated SW

120 pmC 

No

RGW 

No

GTW 

No

CGW 

Tritium, in picocuries per liter

90

80

70

60

50

40

30

20

10

0

-10

II

CGW; as large as 

39,600±380 pCi/L

USGS 22

160.9±0.4 pCi/L

ML 29

-22±13 pCi/L

USGS 83

-190±70 pCi/L

USGS 117

-100±100 pCi/L

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

SW

TVG

RG

GTW

DG

CG

N INL

NE INL

SE INL

C INL

NW INL

SW INL

Natural groundwater 

Figure 27.—Continued
Figures 27–28 109

tac18-1192_fig28a

7.0

7.0

9.0

8.0

11.0

12.0

15.0

14.0

13.4,14.0

10.0

13.0

14.0

11.0

20.0

13.0

12.0

13.0

11.0

15.0,12.5

10.0

14.0

17.0

11.0

11.0

11.0

15.0

11.0

14.0

12.0

10.0

12.0

15

9.6

9.5

8.2

9.5

9.5

8.5

7.3

9.6

14.7

9.4

13

10.5

12.8

13.6

12.7 13.3

13.6 12.8 14.8

14.9

13.7

12.3

13.9

11.6

13.9

13.5

11.8 11.5

11.8

14.6

15.8

12.7

15.5

14.9

15.4

16.9

15.6

13.5

11.6

14.7

11.7

11.4

11.4

18.8

14.1

14.9

13.9

14.6

15.2

12.3

16.3

13.7

11.3

14.3

13.8

13.3

11.5

12.2

10.4 10.3

27.8

48.4

12.8

16.4

12.2

11.2

12.9

12.5

11.2

17.7

11.6

12.5

10.5

14.6

13.2

12.1

13.2

12.8

12.9

12.1

14.4

13.2

14.5

11.7

10.5

11.3

12.1 12.3

12.1

14.2

14.3

13.5

13.9

13.3

14.1

19.3

16.5

12.5

12.3

12.5

16.5 12.5

11.5 11.5

12.3 14.5 12.6 13.6,13.1

18.8 13.1

13.5

13.7,13

11.6

12.9

10.5 6 14.7

57,34 11.5

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

A

18.8

Water temperature, in degrees Celsius

Shallow groundwater

19.3

>14.0 to 16.0

>12.0 to 14.0

>16.0

10.0 to 12.0

<10.0

16.5

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28. Geographic distribution of selected chemical and isotopic constituents in surface water and groundwater, 

Idaho National Laboratory and vicinity eastern Idaho.
110 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28b

344

379

367

444 298

580 839 407

378 375 358

399

384

327

363

590

282

383

528 597

383

600

360

332 282

343 600

506

405

432

568

391

645

357

410

396

345

298

319

387

602

366

396

376

300

299

331

275

353

316

400

820 525

255

387

414

341

350

369

277

550

481

301

359

340

458

483

346

540

684

631

385

346

964

486

258

430

694

338

502

692

848

335

557

307

489

282

929

613

727

265

344

293

313

301

370

249

292

311

352

290

370

341

373

427

275

557

447

279

745 567

354

356

364

392

348

378

376

407

276

324

245

147

321

320

337

262

374

1,100

722

376

443

945

430 621

236 1,480

680

647 608 595

518 348

690 489

1063

351 385

368

358 277

330

313

346

356

343

1,878; 645

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

B

1,878

Specific conductance, in μS/cm at 25 oC

Shallow groundwater

147

500 to <600

400 to <500

≥600

300 to <400

<300

1,480

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 111

tac18-1192_fig28c

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

6.8

8.4

8.4

9.2

8.4 9.0

7.7 8.7

9.1

9.5

9.0

8.7

7.2

9.5

8.6

9.2

9.6 6.1

9.1 8.6

8.0

7.3

7.4

5.3

7.6

6.3

7.5

6.9

8.8

5.1

8.2

8.2

8.0

3.9

8.0

7.9

9.2

4.2 2.4

7.3

8.1

8.1

6.8

6.8

8.2

9.6

6.4

8.2

9.7

6.1

7.4

≈7.3

≈8.0

≈8.4 ≈7.0

9.2

7.2

8.2

8.6

1.8

5.9

7.7

7.8

8.3

4.5

7.4

0.7

9.3

3.4

0.1

6.9

7.7

9.5

8.1

7.8

7.8

4.8

8.1

8.3

7.2

5.4

7.1

0.7

8.3

9.1

6.7

8.4 9.5

6.3

8.3

7.5

8.3

9.1

5.8

7.2

10.3

10.2

10.1

11.4

12.2

11.1

<0.2

11.4

10.5

≈9.2

10.0

<0.2

≈7.8 ≈8.2 ≈8.3

9.0

8.6

8.3

9.0 6.6

11.6

10.2

7.0

8.5

≈2.2

≈8.4

10.0

10.5

6.6

8.8

9.2

oxic/anoxic

≈5.9

≈6.4

≈8.3

≈7.4

≈6.4 ≈7.4

≈8.2

≈8.8

≈7.9

≈7.7

≈7.9 ≈7.2

≈6.3

≈8.2

≈6.6

≈5.6

≈5.8

≈7.5

≈8.0

≈8.3

≈6.9

≈9.2

≈7.6

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

C

3.9

Dissolved oxygen, in milligrams per liter

Shallow groundwater

8.8

8 to 10

6 to 8

≥10

2 to 6

≤0.7

<0.2

EXPLANATION

Estimated value

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

≈8.4

Figure 28.—Continued
112 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28d

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

-3.0

-3.0

-3.0

-3.0

-3.0

-3.0

-3.0 -3.0

-3.0

-3.0

-3.0

-3.1

-3.0

-3.0

-3.0

-2.0

-3.0

-3.0

-3.0

-2.9

-2.3

-2.6

-3.1

-2.8

-2.8

-3.2

-3.2

-2.9

-2.9 -2.9

-2.9

-2.9

-3.2

-2.6

-3.1

-2.6

-2.6

-3.3

-2.8

-3.2

-2.9 -2.7

-2.8

-2.9

-2.8

-2.8

-2.8

-2.8

-2.7

-2.5

-2.8

-3.1

-2.9

-3.1

-2.5

-3.1

-2.8

-2.9

-2.9

-3.0

-2.5

-2.6,-2.6 -2.9

-2.8

-2.6

-2.9

-2.9

-2.9

-2.7

-3.1

-2.8

-3.1

-2.3 -3.5

-2.7

-2.9

-3.1

-2.3

-1.8

-1.8

-2.7

-2.4

-1.9

-1.8

-3.3

-2.4

-3.1

-2.1

-1.9

-2.6

-2.4

-2.4

-2.8

-2.7

-2.5

-2.6

-2.7

-2.4

-3.3

-2.8

-2.6

-2.9

-2.7

-2.7

-2.1

-2.8

-3.1

-2.8 -2.8

-3.1

-2.9

-2.8

-2.9

-2.9

-2.8

-3.5

-2.9

-2.9

-3.3

-2.7

-2.1

-2.3

-3.4

-2.9

-2.6

-2.4

-2.3

-2.9

-3.4

-3.5 -2.8

-2.7

-2.8

-2.8

-3.5

-2.6,-2.7 -2.8-2.7 -2.4

-2.8 -2.9

-3.7

-3.3

-3.0

-2.8

-2.8

-2.3

-3.1

-1.8,-2.8

-3.0

-3.3

Idaho National Laboratory

Little Lost River

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

D

-1.8

Carbon dioxide concentration, as log PCO2

Shallow groundwater

-3.5

-2.1 to -2.4

-2.5 to -2.8

≥ -2.0

-2.9 to -3.2

≤ -3.3

-2.6

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 113

tac18-1192_fig28e

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

10.9

8.4

5.6

5.2

5.9

6.4

149

9.7

4.1

7.2 15.8

11.7

12.7

6.9

38.4

6.4

6.2

41.8

15.5

5.2

4.7

4.3

5.9

4.0

10.0

5.9

6.7

6.1

4.8

4.6

5.5

6.2

120

6.3

5.1

4.3

4.8

23.0

9.1

28.8

6.1

4.7

9.2

27.7

32.4

16.3

20.6

6.1

4.5

5.6

7.4

6.1

4.6

5.5 4.5

9.8

10.2

4.7

5.0

11.5

5.3

7.0

4.6 9.7

5.4 5.4 6.9

6.2

6.3 4.9

6.2

5.0

6.3

5.7

5.9 (USGS 121)

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

E

149

Helium concentration (cm3 STP/g x 10-8)

Shallow groundwater

25 to <35

15 to <25

≥ 35

8 to <15

< 8

5.9

11.5

EXPLANATION

Data from Busenberg and others, 2000

Contaminated groundwater

Deep groundwater or geothermal water

Surface-water site

Groundwater site

Figure 28.—Continued
114 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28f

66

46

49

38

41

39

3430

56 78 43 76

37 40

37

38

41

35

36

74

29

38

60 49

73

44 33

40

37 27

36 85

50

41

49

54

41

74

37

35

44

35

37

33

37

71

41

41

47

25

29

40

29

35

31

51

71 53

32

42

51

34

36

45

26

40

62

49

30

44

38

68

40

64

72

72

71

49

34

85

65

39

53

87

47

42

75

75

19

67

15

65

22

42

69

69

28

37

28

32

32 41

30

30

32

45

28

40

36

29

68

49

26

63

55

23

72 62

38

34

34

54

35

38

45

46 28

27

30

19

42

38

31

35

48

113

109

57

130 24

73

70

41

67

57

61

27

43

26 45

25

46

43

47

50

7,10

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

F

48

87

Calcium concentration, in milligrams per liter

Shallow groundwater

>50 to 60

>40 to 50

> 60

>30 to 40

≤ 30

130

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 115

tac18-1192_fig28g

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

9

8

15

19

15

10

16 21

15

11.2 15

14

19

19

12

15

15 19

20

11

15.6 14

23

24

14

15

19

23

25 35

45

21

16

17

33

14

26

15

13

10

24

22 14

6.5

10

15

12

9.2

9.3

9.5

8.8

8.9

7.7

6.3

4.6

8.6

9.6

9.3

9.6

8.3

9.5

9.3

8.7

4.7

7.4

15.8

15.9

16.2

18.4

13.3

14.9 15.7

16.6

15.2

13.7

15.3

12.3

22.6

24.3

10.2

10.6

15.4

18.7

15.3

14.1

19.1

14.9

15.8

10.6

16.9

15.8

10.1

15.3

15.3

23.3

14.2

15.6

11.3

12.6

12.1

11.9

17.5

17.3

13.3

14.7

14.1

14.9

14.5

14.3

14.1

15.2

19.7

15.1

37.8

20.7

26.7

16.7

16.1

28.6

11.7

11.8

10.3

14.3

13.9

17.8

15.3

26.4 18.6

14.1

13.4

13.8

13.5

11.5

15.7

17.2

15.1

18.3 27.4

23.2 25

22

24

13.4 18

23.1

23

16.0

11.1

11.9

11.4

12

0.5,2.0

22

24

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

G

11.4

9.3

Magnesium concentration, in milligrams per liter

Shallow groundwater

>20 to 25

>15 to 20

> 25

>10 to 15

≤ 10

35

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
116 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28h

87

91

251

222

201

162

178

176

186116

122

146 164

181 173 165

176

180

156

167

264

148

164

247

269

146 113

135

132 123

152 150

163

172

192

170

182

215

182

197

168

151

167

168

261

173

172

201

142

146

171

149

166

158

155

237 149

153

200

219

165

166

192

139

204

232

164

186

171

243

191

113

245

241

195

139

225

269

149

198

168

164

192

226

291

468

179

202

140

237

151

322

218

340

281

132

140

137

148

162 181

131

131

140

182

156

171

167

235

189

140

259

204

144

149 160

162

168

170

209

162

177

155

180

125

120

126

183

163

123

132

200

279

209

195

129 260

261 244

211

250

173 146 199148

187

103 172 176

121 180

166

156

188

208184

900,220

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

H

91

900

Bicarbonate concentration, in milligrams per liter

Shallow groundwater

>225 to 275

>175 to 225

> 275

125 to 175

< 125

279

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 117

tac18-1192_fig28i

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

8

4

8

9

9

8

4.0

17

11

54

16.0

10

47

11

22

14 41

19

24

26

21

15

57 15

14

14

12

62

21

19 17

10

27

40

85

23

28

56

12

17

15

12

18

17

5.2

7.1

9.9

5.1

8.7

8.8

7.6

9.4 9.7

9.2

6.9

8.9

8.2

6.9

7.1

7.4

9.8

7.8

7.8

6.5

5.8

7.5

7.4

5.7

9.5

7.2

9.8

3.2

9.9

5.4

8.1

9.7

5.4

8.8

9.6

2.8

3.6

5.2

5.1

4.8

5.4

11.8

24.8

15.2 10.5 10.6

15.4

12.7

12.6

12.9

12.2

17.7

14.4

13.2

10.5

12.1

15.5

15.9

12.2

20.8

11.7

15.1

13.5

12.9

11.2

26.4

11.4

39.7

51.6

15.7

37.2

12.7

47.3

37.9

38.2

11.9

14.7

17.6

14.8

13.2 14.9

10.8

14.5

14.5

15.9

21.4 14.4

14.7

14.3

14.4

13.7

97

15.4

110

18 13.5 14 16

10.4

13.2 16.7

78.4

25.4

8.2

12 17.9

9.6

7.0

7.2

5.7

6.66.2

390,92

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

I

7.1

9.3

Sodium concentration, in milligrams per liter

Shallow groundwater

>16.0 to 20.0

>12.0 to 16.0

> 20.0

8.0 to 12.0

< 8.0

110

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
118 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28j

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

4.0

3.0

7.0

3.0

3.0 3.0

2.0

3.0

1.0

1.0

3.1

2.0

1.2

1.1

1.1

2.3

2.7

2.4

4.6

3.3

3.6 2.7 2.4

3.5

2.8

2.4

4.4

2.8

3.1

1.7 2.3

2.2

2.7 3.7 2.9

2.9

2.5

3.6

4.2

3.9

3.4

6.4

3.5

2.4

1.6

5.6

1.5

2.9

2.3

1.6

2.8

2.2

2.1

3.5

1.8

4.4

2.4

2.7

3.3

3.2

3.1

4.4 3.5

0.9

1.9

1.3

2.8

1.8

2.7

2.8

2.7

1.6

2.9

2.4

0.9

1.2

1.2

0.9

4.2

2.5

2.8

2.1

3.5

1.8

1.2

0.7

2.9

2.9

3.4

7.3

4.8

7.2

4.3

4.1

6.8

3.5

4.8

5.4

6.5

6.8

5.8

2.8

3.8

3.1

2.9

2.9 2.7

2.4

2.7

2.7

1.4

3.2

2.9

5.2

2.6

3.6

2.3

1.3

2.4

3.1

4.3 3.2

2.3

3.4

3.4

2.9

3.2

2.5

2.1

1.2

0.6

0.9

0.9

1.7

1.4

1.6

13.6

4.3

2.8 2.2

2.4

1.8

2.6

2.8

4.9 6.2

2.6

2.6 2.6

1.8

2.2

2.4

3.0 2.2

7.5,10

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

J

1.6

13.6

Potassium concentration, in milligrams per liter

Shallow groundwater

>4.0 to 5.0

>3.0 to 4.0

> 5.0

2.0 to 3.0

< 2.0

7.0

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 119

tac18-1192_fig28k

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

7.0

1

0.18

0.19

0.23

0.30

0.5

0.30

0.20

0.2

0.20

0.2

0.2

0.20

0.30

0.20

1.30

0.90

0.2 0.2

0.20

0.2

1.20

0.20 0.2

1.5

0.19 0.30

0.41

0.10

0.50

0.90

0.40

0.2

0.14

0.58

0.90

0.16

0.20

0.2

0.12

0.10

0.12

0.22

0.2

0.2

0.22

0.21

0.26

0.23

0.23 0.24 0.45

0.34

0.19

0.32

0.78

0.57

0.15

0.16

0.24

0.22

0.38

0.41

0.43

0.58

0.43

0.21

0.17

0.21

0.21

0.11

0.79

0.13

0.19

0.20

0.23

0.21

0.57

0.57

0.13

0.19

0.12

0.41

0.28

0.21

0.15

<0.1

0.19

0.22

0.29

0.94

0.43

0.54

0.28

0.22

0.15

0.25

0.64

0.36

0.16

0.21

0.19

0.45

0.53

0.54

1.01

0.41 0.48

0.49

0.25

0.89

0.44

0.21

0.19

0.19 0.39

0.25

0.22

0.49

0.44

0.64

0.39

0.26

0.11

0.18

0.21

0.1

0.13

0.120.12

0.30 0.21

0.26 0.15

0.3

0.33

0.220.30

0.30 0.20

0.25

0.21

0.23

0.30.2

13,1.1

<0.1

<0.1

<0.1

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

K

0.1

13

Fluoride concentration, in milligrams per liter

Shallow groundwater

>0.6 to 0.8

>0.4 to 0.6

> 0.8

>0.2 to 0.4

≤ 0.2

0.39

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
120 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28L

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

8

9

8

14

10

12

18

22

26

2231

22

22

22

24 23 32

30

21

25

24

18

34

28

16 21

18

30 27

28

26 26

23 21

29

31

28

37

33

21

16

18

15

26

22

18

30

18

19

23

19

47

25

23

34

29

33

23

19

19

17

19

15

30

24

23

36

24

19

41

24

14

12

16

14

22

23

26

23

20

17

34

29

36

37

37

28

29

37

33

35

48

34

29

28

32

35

46

34

37

34 34

34

34

37

10

21

27

35

62

21

19

32

19

23

34 24 21

24

31

29

13

34

31

27

21

15

10

18

10

11

12

13

21 23

19

25

28

24,28

19

24

27

5.2 26

47,60

23

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

L

10

13.6

Silica concentration, in milligrams per liter

Shallow groundwater

32 to 37

27 to 31

> 37

21 to 26

≤ 20

30.0

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 121

tac18-1192_fig28m

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River 7

8

7

1.0

3

12

38

19 14 14

34

38

13

46

18 21

42 26

69

21

21

17

13

12

64

13

50

12

60

5944

43

10

93

43

55

15

11

74

10

2.5

7.5

9.6

5.5

8.2

8.5

110

9.9

9.9

4.9

8.4

9.1

9.4

9.4

120

2.6

9.9

9.5

7.5

6.6

5.5

6.3

6.2

143

7.7

3.4

5.2

6.7

166

6.8

9.8

8.8

9.5

5.6

7.7

5.4

5.6

3.2

8.2 115

6.5

3.8

2.2

4.8

4.6

3.1

4.8

14.9

14.8

21.7 21.3

13.6

12.6

16.3

17.7

22.2

19.6 10.8

22.5

61.9

13.3

66.5

10.2

37.6

11.8

20.9

11.6

13.1

10.1

10.1

13.6

19.9

15.8

24.1

46.2

36.1

47.5

12.7

16.2

40.4

25.7

12.6

12.3

18.8

18.7

21.6

17.6

16.9

17.2

17.3

14.5

12.6

17.2

150

15.2

66.6

5.2 240

46

35 48

33.9 89.3 151 218

13.7

13.411.9 38.8

82

7.6

9.6

5.7

5

6.3

12,17

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

M

4.8

13.1

Chloride concentration, in milligrams per liter

Shallow groundwater

45.0 to <60.0

30.0 to <45.0

≥ 60.0

15.0 to <30.0

< 15.0

240

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
122 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28n

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

1.6

0.4

0.2

0.5

0.6

0.7

0.81.3

3.0

2.4

1.1 0.6 0.7

1.0

0.7

0.7

0.7

2.1

0.8

1.5

1.1 1.5

2.2

1.8 0.7 0.7

1.4 0.7

0.5 1.6

3.2

1.4

0.8

2.0

2.4

0.8

1.7

0.6

0.4

0.8

0.4

0.3

0.4

1.1

2.3

0.6

0.7

0.9

0.4

0.3

0.5

0.3

1.2

0.9

0.9

2.3 1.2

0.2

0.9

1.0

0.6

0.6

0.6

0.6

2.9

0.6

0.6

0.4

0.3

2.1

0.5

0.8

2.0

1.9

0.7

0.6

4.2

0.8

0.7

0.1

0.9

1.5

5.5

4.4

8.5

0.1

1.7

0.1

1.5

0.1

2.9

4.1

4.9

5.3

1.5

1.3

1.2

2.5

1.0 2.1

1.7

0.7

3.2

0.3

0.4

1.1

1.0

3.6

1.4

0.4

1.9

1.2

0.4 3.7 3.5

0.7

1.1

1.1

0.6

1.2

0.7

0.9

0.8

0.25

0.1

0.2

0.1

0.2

0.1

<0.05

<0.05

<0.05

<0.02

<0.05

<0.1

0.5 1.7

1.9 1.8

2.5 1.0

3.7 1.8 1.3

0.7

1.8

0.6

0.6

0.4

0.8

0.3

2.2

1.7

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

N

0.1

0.4

Nitrate concentration, in milligrams per 

liter as nitrogen

Shallow groundwater

3.0 to <4.0

2.0 to <3.0

≥ 4.0

1.0 to <2.0

< 1.0

3.7

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 123

tac18-1192_fig28o

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

9

9

5

9

9

9

9

4

9

1

26

29

22

29

26

22

38

35

34

21

31

29

25 22 18

25

26

19

23

36

21

27 22

36

27 64

26

23 20

21

39

28

17

39

30

36

18

21

21

25

19

19

22

37

23

26

21

16

18

19

14

13

33

40 39

21

20

23

23

19

10

22

32

34

14

16

26

23

11

73

59

50 44

21

24

60

20

58

16

59

86

53

29

10

40

17

37

91

30

32

42

16

11

12

14

13

14

26

15

18

14

40

30

13

34

24

16

45 28

21

16

17

20

12

29

30

32

11

25

23

18

18

27 150

191

14 200

39

49

35

22

35

31

28

24

17 35

21

20

22

20

(99),32

(4)

(8)

(32)

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

O

18

23

Sulfate concentration, in milligrams per liter

Shallow groundwater

35 to 45

25 to <35

> 45

15 to <25

< 15

22

EXPLANATION

Anoxic water

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

(4)

Figure 28.—Continued
124 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28p

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

78

69

46

35

48 28

65

38 38

32

45

32

43

35 22

29 95

57 56

58

43

52

55

17

47

55

35

65

52

34

78

34

84

68

38

49

74

60 46

71

45

60

58

70

45

87

56

81

78

51

74

62

95

56

29

30

21

26

10

64

97

43

62

96

91

35

36

29

86

86

65

51

44

33

61

62

60

69

149

124

112

143

110

170

190

179

110

114

167 140

163

143

138

112

127

151

164

120

132

135

<100

<100

<100

<100

136

250 342

126

18

18

45

37

130

240

130

21

70

51

63

70

84

63

23

89

17

70

20

80

37

69

19

18

38

49

26

26

32

110

11

45

56

10554

40

<100

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

P

33

70

Barium concentration, in micrograms per liter

Shallow groundwater

> 90

>60 to 90

>30 to 60

< 30

342

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 125

tac18-1192_fig28q

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

8

8

18

21

21

39

23

18

26 24

23 38 23

35

22

16

30

30

47

44

30 22

29

18 15

19

43

37

36

52

38

26

33

32

33

13

18

36

33

16

25

13

57

25

19

80

45

42

25

26

35

30

20

17 18

19

16

17

20

20

35

90

25

82

78

84

90

50

48

36

21

19

25

40

19

72

70

24

20 27 21

21

40

41

11

46

35

26

12

14

13

117

21

30

23 21

14

560,900

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

Q

8

900

Boron concentration, in micrograms per liter

Shallow groundwater

> 40 to 50

>30 to 40

> 50

>20 to 30

≤ 20

39

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
126 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28r

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

6

3.0

5

6

2.0

5

5

6

2.0

2.7

1.0

2.6

2.0

<6

<4

18

25

20

28

47

71

16

32

14

16

12

18

<4

3.3

5.5

3.2

6.7

3.6

5.1

2.52.1

2.7 2.5 4.3

2.2

6.9

2.9

2.5 2.8

2.6

2.3

2.2

4.3

3.7

3.5

5.2

1.4

2.1

2.7

2.1

3.3

1.3

7.3

2.5

2.4

3.5

1.7

2.2

2.4

1.8

1.5

2.9

2.2

2.5

1

6

7

2.5

2.3

3.6 2.5

3.9

2.9

1.1

3.1

16

11

28

23

19

18

24

36

18

24

26

20

12

15

48

10

24

13

12

18

25

10.2

1.7

2.8 2.4

4.2

47

1.9

2.0

1.6

2.31.7

3.4

280,50

9 5

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

R

1.1

280

Lithium concentration, in micrograms per liter

Shallow groundwater

20 to 30

9 to <20

> 30

3.0 to <8

< 3.0

9

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 127

tac18-1192_fig28s

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

92

61

77

91

77

323

177

163

201

230

256

197130

333

244 532

205 307

189

120

235

184

186

308

111

133

252

316

240

190

230

171 157

214 390

246

196

158

256

196

450

219

114

256

165

208

188

178

357

220

202

254

120

182

189

131

133

230

470 270

211

206

215

188

231

240

322

132

135

137

322

126

300

244

181

363

316

337

146

308

329

160

502

180

312

331

400

127

100

131 170

323

145

347

251

217

303

195 483 370

197

164

152

257

125

208

210

218

118

105

150

143

164

210

350

309

222

230 310

360

334

484

231

244

118

144

150

260

245

145

255

276

276

150

90

150,100

(Howe City well) 232

(well 52098-2)

(well 52098-1)

1,000

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

S

1.1

280

Strontium concentration, in micrograms per liter

Shallow groundwater

>300 to 400

>200 to 300

> 400

100 to 200

< 100

9

EXPLANATION

Data from Johnson and others (2000)

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

150

Figure 28.—Continued
128 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28t

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

1.9

2.2

1.6

2.8

1.1

1.4

1.3 2.1 2.3

2.0 1.7 1.8

2.2

2.2

1.5

1.5

2.5

1.3

1.5

1.8

1.5

2.4

1.2 1.0 1.4

2.5

2.5

2.3

2.0

3.0

2.4

1.9

0.4

1.6

2.1

1.7

1.8

2.4

2.4

1.7

1.6

2.1

2.3

1.8

1.5

1.8

1.7

1.7

1.4

2.1

1.7

1.9

2.0

2.1

1.7

1.2

1.9

2.0

1.8

0.02

0.1

3.6

3.2

2.2

1.6

1.8

1.9

2.0

2.0

2.3 2.3

1.9

2.1

1.9

2.5

1.7

2.4

2.1

0.9

2.2

1.9

2.3

2.2

1.7

0.5

3.2

0.2,1.9

(Crooked Creek well)

1.7

1.6

1.1

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

T

0.5

1.7

Uranium concentration, in micrograms per liter

Shallow groundwater

2.0 to 2.5

1.5 to <2.0

> 2.5

1.0 to <1.5

< 0.5

2.8

EXPLANATION

Data from Roback and others (2001)

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

3.2

Figure 28.—Continued
Figures 27–28 129

tac18-1192_fig28u

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

-17.32

-18.35

-18.13

-18.44

-17.82

-17.95

-17.61 -18.05

-17.74

-17.87 -17.62,-17.51

-17.64 -17.78

-17.85

-17.55

-18.09

-17.80

-17.50

-17.84

-17.78

-17.99

-17.55

-18.13 -18.14

-17.89 -16.90

-17.68

-17.81

-17.67

-17.66

-17.80

-17.94

-17.62

-18.07

-18.11

-17.53

-18.49

-17.61

-17.47

-17.92

-17.75

-17.78

-17.93

-17.62

-17.82

-17.71

-17.82

-18.06

-18.04

-18.10

-17.96

-17.98

-17.74

-17.92

-17.98

-18.15

-18.20

-17.64

-18.14

-18.50

-17.32

-18.11

-17.76

-15.86

-17.59

-17.19

-17.02

-17.65

-18.10

-18.03

-17.13

-16.98

-17.85

-17.90

-17.26

-15.55

-14.84

-14.88

-17.35

-17.62 -17.45

-17.62

-17.33 -18.55

-18.35

-17.62

-18.39

-17.58

-17.93

-17.94

-18.13

-17.23 -17.71

-17.90

-17.72

-17.73

-17.69

-17.74

-17.88

-18.27

-15.97

-17.72

-17.94

-16.24

-18.62

-18.57

-17.17

-17.4

-17.84

-17.97

-18.07

-18.10 -17.90

-17.78 -17.70

-18.34

-17.92

-18.1

-17.33

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

U

-16.24

-18.49

Stable isotope ratio of oxygen-18/oxygen-16 

(δ18O), in permil

Shallow groundwater

>-17.40 to -17.00

>-17.70 to -17.40

> -17.00

>-17.90 to -17.70

> -18.20 to -17.90

≤ -18.20

-16.90

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
130 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28v

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

-9.2 -9.30

-8.90

-7.06

-9.29

-9.17

-9.41 -8.51

-7.9

-7.1

-8.80

-8.0

-8.21 -6.94

-5.92

-7.37

-8.97

-6.41

-9.38

-8.75

-9.38 -10.6

-10.6 -9.92,-10.67 -10.3

-10.6 -9.08 -8.93

-9.81

-9.68

-10.4

-9.47

-9.39

-9.87

-8.61

-5.72

-7.37

-8.01

-9.51

-9.48

-8.64

-9.64

-11.67

-10.7

-9.12

-8.35

-8.48

-8.17

-9.22

-9.10

-7.09

-5.61

-8.42

-6.13

-9.90

-8.76

-6.17

-9.12

-5.55

-3.90

-9.47

-13.32

-11.4

-13.2

-13.4

-11.2

-10.59

-9.27

-9.32

-12.0 -9.43

-9.39

-10.6

-10.2

-11.21

-6.06

-6.57

-7.98

-10.9

-11.47

-10.60

-10.09

-10.02

-11.75

-13.55

-10.09

-10.18

-10.19

-11.84

-10.21

-12.00

-12.28

-15.00

-11.70

-12.60

-13.14

-12.65

-11.14

-10.33

-12.78 -8.87

-10.8

-11.3

-11.0

-8.78

-11.17

-8.88

-8.84

-10.9

-8.48

-9.06

-10.7

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

V

-7.98

-8.01

Stable isotope ratio of carbon (δ13C), in permil

Shallow groundwater

-9.0 to -8.0

-10.0 to -9.0

> -8.0

> -11.0 to -10.0

-12.0 to -11.0

< -12.0

-8.01

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 131

tac18-1192_fig28w

16.3

4.7

9.8

5.7

5.8

4.8 5.3

9.0

6.1

6.0

8.6

5.7

9.5

5.6

5.8

5.2

7.2

7.5

9.2

8.6

3.3

5.1

7.7

5.6

6.9

8.4

8.3

8.2

7.6

7.9

6.9

6.9

4.4

11.8

11.0

10.2

10.7

10.5

11.9

11.0

11.9

1.8

1.6

8.2 Birch Creek at 8-mile Canyon Road

Camas Creek at shearing

corral near Kilgore, 6.9

15.3

11.6

USGS Site No.

431857112405501

USGS Site No.

433852112165201

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

W

4.4

11.9

Stable isotope ratio of sulfur (δ34S), in permil

Shallow groundwater

>9.0

6.0 to 9.0

4.0 to <6.0

< 4.0

11.9

EXPLANATION

Data from Wood and Low (1988)

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

11.6

Figure 28.—Continued
132 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28x

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

6.0 5.1

8.1

5.4

6.6

5.9

6.5

6.5

5.3

7.6

6.3

5.9

5.1

7.2

8.3

6.3

5.4

6.0

4.7

4.7

7.3

6.3

5.8

6.2

6.0

7.0

7.1

7.1

4.7

6.5

6.3

8.1

6.9

9.5

6.7

5.6

5.4

6.5

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

X

6.3

Stable isotope ratio of nitrogen (δ15N), in permil

Shallow groundwater

>6.0

≤ 6.0

6.6

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface-water site

Groundwater site

Figure 28.—Continued
Figures 27–28 133

tac18-1192_fig28y

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

1.01

1.00

1.02

1.04

1.00

0.99

0.99

0.03

1.03

0.001

7.46

3.07 0.69 1.26

1.29

0.67

1.12

1.06

1.28

1.27

0.58

9.70

2.07

0.76

1.26

1.25

1.14

1.43

1.82

1.26

1.11

1.21

1.57

1.13

1.17

1.16

1.75 (USGS 121)

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

Y

Isotope ratio of helium in environmental sample 

divided by isotope ratio of helium in air (Rs

/Ra)

Shallow groundwater

1.00 to <1.25

1.25 to <1.50

1.50 to 4.00

> 4.00

< 1.00

7.46

EXPLANATION

Data from Busenberg and others (2000)

Contaminated groundwater

Surface-water site

Groundwater site

1.75

Figure 28.—Continued
134 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28z

0.71047

0.71039

0.71220 0.71057

0.71043

0.71072 0.71023

0.71053

0.70962

0.71008

0.70981 0.70968

0.71012

0.71026

0.71040

0.70957

0.70993

0.71107

0.70951

0.71014

0.71115

0.71038

0.71129

0.71057

0.71061

0.71008

0.71029

0.70998

0.71021

0.71057

0.71008

0.71031

0.71091

0.71085

0.71059

0.71159

0.71037

0.70992

0.71006 0.71091

0.71048

0.70998

0.71143

0.71073

0.71056

0.71043 0.71042

(Howe city well) 0.71104

0.70980, 0.70935

0.71082

0.71040

0.71198

0.71256

0.70943

0.70971

(well 52098-2)

(well 52098-1)

0.71434

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

Z

Strontium-87/Strontium-86

Shallow groundwater

0.71000 to 0.71050

0.71050 to 0.71100

0.71100 to 0.71150

>0.71150

0.70950 to 0.71000

<0.70950

EXPLANATION

Data from Johnson and others (2000)

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

0.71006

0.70971

0.71056

0.71043

Figure 28.—Continued
Figures 27–28 135

tac18-1192_fig28aa

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

1.54

1.71

2.27

2.55

2.49 2.31 2.32

2.56

2.16

2.41

2.28

2.32

1.92

2.23

2.07

2.45

2.61

2.13

2.35

2.82

3.01

2.91

1.96

2.77

2.64

2.24

2.47

2.22

2.49

2.89

2.27

2.05

2.35

2.45

3.01

2.83

2.50

3.05

2.07 2.53

2.48

2.33

2.99

3.01

2.25

2.12

2.23

2.07, 3.14

2.07

2.86

(Crooked Creek well)

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

AA

Uranium-234/Uranium-238 (activity ratio)

Shallow groundwater

2.00 to 2.30

2.30 to 2.70

2.70 to 3.00

>3.00

<2.00

EXPLANATION

Data from Roback and others (2001)

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

2.83

2.86

2.25

2.31

Figure 28.—Continued
136 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28bb

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

0

0

0

<2

0

20

69

48

52

<16

268

174

<80

107

312 230

4.2

2.9

1.2

0

3.9

0

1.3

161

0.5

1.8

0.3

5.8

<10

900

3.7

4.2

<23

2.5

8.1

<13

298 144

131

<26

0.1

3.1

0.4

4.7

9.7

2.2

9.7

8.6

<10

<13

<10

0.2

3.2

6-32

15

73

11

10

12

14

36

23

50

19

72

32

48

47

28

12

51

13 52

52

51

57

45

58

33

11

56

53

13

13

48

<120

37

23

12

13

84

13

27

26-51

3,800

4,800

1,670

1,600

1,200

1,130

12

3,100

19-45

13-38

19-45

22-48 25-51 26-51

26-51

10-35

39,600

10,100

14,100 19,500

27,600

90 77 71 58

16,800 10,500

24,500

5,200 27,400;10,800

<59

2,000

1,600 0 1,700

52

14

17

1.3

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

BB

Uncertainties (1σ) and approximations

Most INL groundwater: ≤2.3 pCi/L or ≤10 percent.

Some contaminated groundwater: >10 percent.

Larger uncertainties were indicated by a range of 

values or a “<” symbol.

If a tritium value plus the uncertainty was <0 

pCi/L, the value is shown as 0 pCi/L.

Tritium concentration, in picocuries per liter 

(pCi/L)

Shallow groundwater

10 to 20 (mix, young and old groundwater)

>20 to <30 (mix, mostly young groundwater)

30 to 161 (young groundwater)

>75 (groundwater contaminated with tritium)

4.0 to <10 (mix, mostly old groundwater)

<4.0 (old groundwater)

EXPLANATION

Contaminated groundwater

Deep groundwater or geothermal water

Surface water

Surface-water site

Groundwater site

1.3

52

39,600

Figure 28.—Continued
Figures 27–28 137

tac18-1192_fig28cc

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

8

9 2

6

6 0

6

7

1

4

1

5

8

7

9

0

30

14

23

11 33

3242 22 22

55 16

33

16

10

55

53

40

21

35

83

71

88

86

57

38

84

27

82

13

13

23

10

97

62

30

34

60

91

69 34 25

56

10

89

38

36

18

27

15 32

24

72

29

46

67

15

28

96

4 (USGS 121)

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

CC

Terrigenic helium, in percent

Shallow groundwater

>10 to 30

>30 to 50

>50 to 80

>80

≤ 10

EXPLANATION

Data from Busenberg and others (2001)

Contaminated groundwater

Deep groundwater or geothermal water

Surface-water site

Groundwater site

96

6

4

Figure 28.—Continued
138 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

tac18-1192_fig28dd

Birch Creek

Mud Lake

Medicine Lodge Creek

Big Lost River

Arco

Howe

Hamer

Camas

Dubois

Spencer

Terreton

Monteview

Blue Dome

Atomic City

Idaho National Laboratory

Little Lost River

65

48

76

53

83

59

72

65

77

86

80

84

62

65

86

22

70

37

21

43

85

54

51

78

31

59

63

~35,000 yrs

Beaverhead Mountains

Lost River Range

Lemhi Range

0 5 10 MILES

0 5 10 KILOMETERS

113°15' 113°00' 112°45' 112°30' 112°15'

44°

15'

44°

00'

43°

45'

43°

30'

43°

15'

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000.

Coordinate system and datum: NAD 1927 UTM Zone 12N

DD

Carbon-14, in percent modern carbon

Shallow groundwater

<40

50 to 65

≥ 70

EXPLANATION

Deep groundwater or geothermal water

Surface-water site

Groundwater site

96

Figure 28.—Continued
Tables 10–17
140 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 10. Site name, primary source of data, and alternate and abbreviated names for water-quality sites, Idaho National Laboratory 

and vicinity, eastern Idaho.

[Springs are shown in italics. Locations of sites shown in figures 8–9. Alternate name: CC ##, Sample number in Rattray and Ginsbach (2014); ML ##, Site 

number in Rattray (2015). Abbreviations: ft, foot; INL, Idaho National Laboratory; na, not applicable; RWMC, Radioactive Waste Management Complex; 

USGS, U.S. Geological Survey]

Site 

name

Primary source 

of data

Alternate 

name

Abbreviated 

name

Surface water

Big Lost River at Mackay Dam Busenberg and others, 2000 BLR at MD BLR MD

Big Lost River below Mackay Reservoir Ott and others, 1994 na na

Big Lost River at Bridge near Mackay Busenberg and others, 2000 BLR at Br nr Mackay BLR M

Big Lost River near Arco Bartholomay and others, 2015 BLR nr Arco BLR A

Big Lost River below INL Diversion Bartholomay and others, 2015 BLR blw INL Div BLR INL

Big Lost River near Atomic City U.S. Geological Survey, 2014 BLR nr AC BLR AC

Big Lost River below lower Lincoln Boulevard 

Bridge near Howe

Busenberg and others, 2000 BLR, nr NRF, Lincoln Blvd BLR LLBB

Birch Creek at Kaufman Guard Station Swanson and others, 2003 BC at KGS BC KGS

Birch Creek at Blue Dome Busenberg and others, 2000 BC at BD BC BD

Camas Creek below diversion near Camas 

National Wildlife Refuge

Rattray, 2015 CC 99, ML 78 CC

Little Lost River near Clyde Swanson and others, 2002 LLR nr Clyde LLR C

Little Lost River near Howe Busenberg and others, 2000 Little Lost River north of Howe LLR H

Mud Lake near Terreton Busenberg and others, 2000 Camas Creek near Mud Lake ML

Tributary Valley groundwater

Big Lost River Valley

Arco City Well 4 Busenberg and others, 2000 na ACW4

Coates Carkeet and others, 2001 na na

Fulton Carkeet and others, 2001 na na

Hill Carkeet and others, 2001 na na

Lambert Carkeet and others, 2001 na na

MSR Carkeet and others, 2001 na na

Muffett Carkeet and others, 2001 na na

Owen Carkeet and others, 2001 na na

Wheeler Carkeet and others, 2001 na na

Wildhorse Guard Station Carkeet and others, 2001 na WGS

Little Lost River Valley

Harrell Swanson and others, 2002 na na

Mays Swanson and others, 2002 na na

Nicholson Swanson and others, 2002 na na

Oar Swanson and others, 2002 na na

Pancheri Busenberg and others, 2000 Pancheri 6 na

Ruby Farms Swanson and others, 2002 na RF

Sorenson Swanson and others, 2002 na na

Birch Creek Valley

Kaufman Guard Station Swanson and others, 2003 na KGS

McKinney Swanson and others, 2003 na na

P&W 2 Busenberg and others, 2000 P and W 2 P&W2

USGS 126b Swanson and others, 2003 na 126b

Wagoner Busenberg and others, 2000 2Wagoner Ranch W

Wagoner Ranch Swanson and others, 2003 na WR

Beaverhead Mountains

ML 55 Rattray, 2015 Blue Spring na

ML 59 Rattray, 2015 Heart Spring na
Tables 10–17 141

Table 10. Site name, primary source of data, and alternate and abbreviated names for water-quality sites, Idaho National Laboratory 

and vicinity, eastern Idaho.—Continued

Site 

name

Primary source 

of data

Alternate 

name

Abbreviated 

name

Regional groundwater

East Mud Lake area

ML 2 Rattray, 2015 na na

ML 5 Rattray, 2015 CC 15 na

ML 6 Rattray, 2015 CC 18 na

ML 9 Rattray, 2015 na na

ML 12 Rattray, 2015 Davies, CC 20 na

ML 13 Rattray, 2015 na na

ML 15 Rattray, 2015 na na

ML 18 Rattray, 2015 na na

North Mud Lake area

ML 17 Rattray, 2015 Killian na

ML 26 Rattray, 2015 na na

ML 28 Rattray, 2015 na na

ML 34 U.S. Geological Survey, 2014 na na

Reno Ranch Swanson and others, 2003 na RR

West Mud Lake area

ML 24 Rattray, 2015 Hawker na

ML 30 Rattray, 2015 Holdaway na

ML 31 Rattray, 2015 Maughan na

ML 33 U.S. Geological Survey, 2014 na na

Groundwater with geothermal input

ML 25 Knobel and others, 1999a Park Bell na

ML 27 Rattray, 2015 na na

ML 29 Knobel and others, 1999a Stoddart na

Southwest Mud Lake area

ML 19 Busenberg and others, 2000 Engberson na

ML 22 Busenberg and others, 2000 USGS 4 na

ML 23 Rattray, 2015 Martin na

Southeast INL Boundary area

Highway 2 U.S. Geological Survey, 2014 na Hwy2

Kettle Butte Farms U.S. Geological Survey, 2014 na KBF

SE of Atomic City U.S. Geological Survey, 2014 na SE of AC

USGS 3A Robertson and others, 1974 na 3A

USGS 101 Busenberg and others, 2000 na 101

Geothermal water

INEL-1 2,000 feet1 Mann, 1986 INEL-1 2000’ INEL-1 2000 ft

INEL-1 10,300 feet1 Mann, 1986 INEL-1 10300’ INEL-1 10300 ft

ML 57 Rattray, 2015 Lidy Hot Springs na

ML 58 Rattray, 2015 Warm Spring na

Groundwater at the Idaho National Laboratory

Deep groundwater

EBR 1 Busenberg and others, 2000 na EBR1

Site 9 Busenberg and others, 2000 na Site9, S9

Site 14 Busenberg and others, 2000 na Site14, S14

USGS 7 Busenberg and others, 2000 na 7

USGS 15 Busenberg and others, 2000 na 15
142 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 10. Site name, primary source of data, and alternate and abbreviated names for water-quality sites, Idaho National Laboratory 

and vicinity, eastern Idaho.—Continued

Site 

name

Primary source 

of data

Alternate 

name

Abbreviated 

name

Contaminated groundwater

Advanced Test Reactor Complex

USGS 65 Knobel and others, 1999a na 65

Idaho Nuclear Technology and Engineering Center

CFA 1 Busenberg and others, 2000 na CFA1

CFA 2 Busenberg and others, 2000 na CFA2

USGS 20 Knobel and others, 1999a na 20

USGS 36 Busenberg and others, 2000 na 36

USGS 57 Knobel and others, 1999a na 57

USGS 82 Busenberg and others, 2000 na 82

USGS 85 Knobel and others, 1999a na 85

USGS 104 Busenberg and others, 2000 na 104

USGS 105 Busenberg and others, 2000 na 105

USGS 108 Busenberg and others, 2000 na 108

USGS 109 Busenberg and others, 2000 na 109

USGS 112 Busenberg and others, 2000 na 112

USGS 113 Busenberg and others, 2000 na 113

USGS 115 Busenberg and others, 2000 na 115

USGS 116 Busenberg and others, 2000 na 116

USGS 124 Busenberg and others, 2000 na 124

Naval Reactors Facility

NRF 6 Knobel and others, 1999b na N6

NRF 9 Knobel and others, 1999b na N9

NRF 10 Knobel and others, 1999b na N10

NRF 11 Knobel and others, 1999b na N11

NRF 12 Knobel and others, 1999b na N12

NRF 13 Knobel and others, 1999b na N13

Radioactive Waste Management Complex

RWMC M3S Busenberg and others, 2000 na M3S

RWMC M7S Busenberg and others, 2000 na M7S

RWMC Production Knobel and others, 1992 RWMC Prod RP

USGS 87 Knobel and others, 1992 na 87

USGS 88 Knobel and others, 1992 na 88

USGS 90 Knobel and others, 1992 na 90

USGS 120 Busenberg and others, 2000 na 120

Test Area North

TAN Disposal Knobel and others, 1992 TAN Disp TD

TDD 1 Knobel and others, 1992 na T1

TDD 2 Knobel and others, 1992 na T2

USGS 24 Busenberg and others, 2000 na 24

Natural groundwater

North INL Area

ANP 6 Busenberg and others, 2000 na ANP6

ANP 8 Knobel and others, 1992 na ANP8

IET 1 Disposal Busenberg and others, 2000 ANP 4 IET1

No Name 1 Busenberg and others, 2000 TAN Exploration NN1

PSTF Test Busenberg and others, 2000 na na

TDD 3 Knobel and others, 1992 na T3
Tables 10–17 143

Table 10. Site name, primary source of data, and alternate and abbreviated names for water-quality sites, Idaho National Laboratory 

and vicinity, eastern Idaho.—Continued

Site 

name

Primary source 

of data

Alternate 

name

Abbreviated 

name

Natural groundwater—Continued

Northeast INL Area

ANP 9 Busenberg and others, 2000 na ANP9

USGS 26 Busenberg and others, 2000 na 26

USGS 27 Busenberg and others, 2000 na 27

USGS 29 Busenberg and others, 2000 na 29

USGS 31 Busenberg and others, 2000 na 31

USGS 32 Busenberg and others, 2000 na 32

Southeast INL Area

Arbor Test 1 Busenberg and others, 2000 Arbor Test AT1

Area II Busenberg and others, 2000 Area 2 na

Atomic City Busenberg and others, 2000 na AC

Leo Rogers 1 Busenberg and others, 2000 na LR1

USGS 1 Busenberg and others, 2000 na 1

USGS 2 Busenberg and others, 2000 na 2

USGS 14 Busenberg and others, 2000 na 14

USGS 100 Busenberg and others, 2000 na 100

USGS 107 Busenberg and others, 2000 na 107

USGS 110A Busenberg and others, 2000 na 110A

Central INL Area

Badging Facility Well Busenberg and others, 2000 na BFW

NPR Test Busenberg and others, 2000 NPR-W01 na

USGS 5 Busenberg and others, 2000 na 5

USGS 6 Busenberg and others, 2000 na 6

USGS 17 Busenberg and others, 2000 na 17

USGS 18 Busenberg and others, 2000 na 18

USGS 83 Busenberg and others, 2000 na 83

USGS 103 Busenberg and others, 2000 na 103

Northwest INL Area

Fire Station 2 Busenberg and others, 2000 na FS2

INEL-1 WS Busenberg and others, 2000 WS INEL 1 INEL1

NRF 2 Knobel and others, 1992 na N2

NRF 7 Knobel and others, 1999b na N7

NRF 8 Knobel and others, 1999b na N8

Site 4 Busenberg and others, 2000 na Site4, S4

Site 17 Busenberg and others, 2000 na Site17, S17

Site 19 Busenberg and others, 2000 na Site19, S19

USGS 12 Busenberg and others, 2000 na 12

USGS 19 Busenberg and others, 2000 na 19

USGS 22 Busenberg and others, 2000 na 22

USGS 23 Busenberg and others, 2000 na 23

USGS 97 Busenberg and others, 2000 na 97

USGS 98 Busenberg and others, 2000 na 98

USGS 99 Busenberg and others, 2000 na 99

USGS 102 Busenberg and others, 2000 na 102

USGS 134 Bartholomay and Twining, 2010 USGS 134 Zone 5 134
144 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 10. Site name, primary source of data, and alternate and abbreviated names for water-quality sites, Idaho National Laboratory 

and vicinity, eastern Idaho.—Continued

Site 

name

Primary source 

of data

Alternate 

name

Abbreviated 

name

Natural groundwater—Continued

Southwest INL Area

Highway 3 U.S. Geological Survey, 2014 na Hwy3

Middle 2051 Bartholomay and Twining, 2010 Middle 2051 Zone 5 M2051

USGS 8 Busenberg and others, 2000 na 8

USGS 9 Busenberg and others, 2000 na 9

USGS 11 Busenberg and others, 2000 na 11

USGS 86 Busenberg and others, 2000 na 86

USGS 89 Busenberg and others, 2000 na 89

USGS 117 Busenberg and others, 2000 na 117

USGS 119 Knobel and others, 1992 na 119

USGS 125 Busenberg and others, 2000 na 125

USGS 135 Bartholomay and others, 2015 USGS 135 Zone 10 135

1

INEL-1 2,000 feet and INEL-1 10,300 feet are both from borehole INEL-1. Samples identified as INEL-1 2,000 feet were collected from a depth interval of 

1,511–2,206 feet below land surface, and samples identified as INEL-1 10,300 feet were collected from a depth interval of 4,210–10,365 feet below land surface.

2

Referred to as Wagoner Ranch in Busenberg and others (2000).
Tables 10–17 145

Table 11. Site information, including site name, U.S. Geological Survey site number, location, altitude, well depth, open interval, approximate depth to water, depth of open intervals below water table, aquifer material, water use, and hydraulic conductivity, Idaho National Laboratory and vicinity, eastern Idaho.[Well construction information from the U.S. Geological Survey (2014), Idaho Department of Water Resources (2014), Busenberg and others (1998), and Mann (1986). Hydraulic conductivity data from Anderson and others (1999) and Mann (1986). Springs are shown in italics. Locations of sites shown on figures 8–9. Site name: Alternate names used in other reports shown in table 10. Depth of open intervals: May include multiple open intervals. Abbreviations: ~, approximate; CNWR, Camas National Wildlife Refuge; ft, foot; ft bls, foot below land surface; ft bwt, foot below water table; INL, Idaho National Laboratory; na, not applicable; nd, not determined; USGS, U.S. Geological Survey; unk, unknown; <, less than; >, greater than] 

Site 

name

USGS site 

No.

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

Altitude of 

land surface 

(ft)

Depth 

of well 

(ft bls)

Extent of 

open 

intervals 

(ft bls)

Depth to 

water table 

(ft bls)

Depth of open 

intervals below 

water table 

(ft bwt)

Aquifer 

material

Water 

use

Estimated 

hydraulic 

conductivity 

(ft/d as log K)

Surface water

Big Lost River at Mackay 

Dam

13126000 43.951389 -113.675000 6,000 na na na na na na na

Big Lost River below 

Mackay Reservoir

13127000 43.939167 -113.648333 5,946 na na na na na na na

Big Lost River at Bridge 

near Mackay

13127700 43.886296 -113.616967 5,873 na na na na na na na

Big Lost River near Arco 13132500 43.581944 -113.270833 5,240 na na na na na na naBig Lost River below 

INL Diversion

13132520 43.515833 -113.081944 5,000 na na na na na na na

Big Lost River near 

Atomic City

13132530 43.547129 -113.009165 4,950 na na na na na na na

Big Lost River below 

Lower Lincoln Blvd

13132553 43.670740 -112.875829 4,820 na na na na na na na

Birch Creek at Kaufman 

Guard Station

13116980 44.241298 -112.971673 6,470 na na na na na na na

Birch Creek at Blue 

Dome

13117020 44.153333 -112.909167 6,050 na na na na na na na

Camas Creek below 

diversion nr CNWR

13114150 43.980464 -112.248592 4,829 na na na na na na na

Little Lost River near 

Clyde

13117500 44.192222 -113.289444 6,030 na na na na na na na

Little Lost River near 

Howe

13119000 43.870278 -113.087778 5,020 na na na na na na na

Mud Lake near Terreton 13115000 43.891389 -112.358056 4,775 na na na na na na na

Tributary Valley groundwater

Big Lost River Valley

Arco City Well 4 433758113181701 43.632680 -113.305562 5,320 250 198–214 ~132 ~66–82 Alluvium Production ndCoates 440323113533402 44.056305 -113.893648 6,353 88 60–80 38 22–42 Alluvium Domestic ndFulton 440803113541701 44.134085 -113.905592 6,340 30 unk 8 unk Alluvium Domestic ndHill 435956113493401 43.998861 -113.825722 6,195 80 42–78 32 10–46 Alluvium Domestic ndLambert 435351113350301 43.897407 -113.585020 5,854 50 50 5 45 Alluvium Domestic ndMSR 440454113554401 44.081584 -113.929761 6,380 unk unk 75 unk Alluvium Irrigation ndMuffett 435011113223201 43.836292 -113.376400 5,628 63 40–59 36 4–23 Alluvium Domestic nd
146 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho Table 11. Site information, including site name, U.S. Geological Survey site number, location, altitude, well depth, open interval, approximate depth to water, depth of open intervals below water table, aquifer material, water use, and hydraulic conductivity, Idaho National Laboratory and vicinity, eastern Idaho.—Continued Site name USGS site No. Latitude (decimal degrees) Longitude (decimal degrees) Altitude of land surface (ft) Depth of well (ft bls) Extent of open intervals (ft bls) Depth to water table (ft bls) Depth of open intervals below water table (ft bwt) Aquifer material Water use Estimated hydraulic conductivity (ft/d as log K) Big Lost River Valley—Continued Owen 433908113203101 43.652124 -113.342787 5,391 114 113–114 42 71–72 Basalt Domestic nd Wheeler 434345113203401 43.729068 -113.343620 5,455 80 62–78 48 14–30 Alluvium Domestic nd Wildhorse Guard Station 435311114060101 43.886278 -114.101417 7,065 264 264 14 250 Alluvium Domestic nd Little Lost River Valley Harrell 434940113005601 43.827944 -113.018139 4,880 118 117–118 71 46–47 Alluvium Domestic nd Mays 434558112585301 43.765183 -112.982223 4,805 540 unk 273 unk Basalt Domestic nd Nicholson 440003113085101 44.000611 -113.148389 5,403 130 127–130 81 46–49 Alluvium Domestic nd Oar 440558113140301 44.099351 -113.235010 5,790 80 unk 35 unk Alluvium Domestic nd Pancheri 435728113103701 43.957806 -113.177889 5,375 87 37–87 25 12–62 Alluvium Irrigation nd Ruby Farms 434751112571801 43.797405 -112.955834 4,805 149 unk 125 unk Basalt Domestic nd Sorenson 441052113171001 44.181333 -113.287056 6,037 128 54–128 40 14–88 Alluvium Irrigation nd Birch Creek Valley Kaufman Guard Station 441406112582601 44.234889 -112.975083 6,400 80 unk 2 unk Alluvium Domestic nd McKinney 441113112560601 44.186852 -112.935837 6,205 43 39–43 12 27–31 Alluvium Domestic nd P&W 2 435419112453101 43.905184 -112.759384 4,891 378 313–383 317 0–66 Basalt Production 3.30 USGS 126b 435529112471401 43.924559 -112.787746 4,989 472 407–472 412 0–60 Basalt Monitoring nd Wagoner 440957112544301 44.165740 -112.912780 6,125 150 unk 10.7 unk Alluvium Domestic nd Wagoner Ranch 440813112532201 44.136851 -112.890280 6,010 295 294–295 250 44–45 Alluvium Domestic nd Beaverhead Mountains ML 55 440951112311701 44.164082 -112.522444 5,047 unk unk unk unk Rhyolite Commercial nd ML 59 441741112440701 44.294667 -112.736355 7,458 unk unk unk unk Quartzite na nd Regional groundwater Highway 2 433307112300001 43.551854 -112.500817 5,217 783 741–786 725 16–61 Basalt Production nd Kettle Butte Farms 433526112244201 43.590417 -112.411694 5,205 851 19–851 698 0–153 Basalt Domestic nd ML 2 435028112202601 43.925333 -112.204694 4,784 275.5 120–160 10 110–150 Basalt Domestic nd ML 5 441222112142701 44.206021 -112.241654 5,240 580 20–580 450 0–130 Basalt Stock nd ML 6 435846112145601 43.979353 -112.249703 4,805 255 53–255 104 30–86 Basalt Irrigation nd ML 9 435229112163202 43.874417 -112.276639 4,795 152 18–152 72 0–80 Basalt Irrigation nd ML 12 435241112185201 43.878500 -112.315611 4,785 218 167–218 189 0–29 Basalt Domestic nd ML 13 434624112194601 43.772972 -112.332389 4,900 350 16–350 264 0–86 Basalt Irrigation nd ML 15 434407112285101 43.916806 -112.359028 4,877 425.5 unk 110 <316 Basalt Irrigation nd ML 18 435712112263201 43.953583 -112.443417 4,805 88 30–88 37 0–51 Basalt Irrigation nd ML 17 441456112234701 44.248945 -112.397388 5,414 405 365–405 270 95–135 Basalt Domestic nd ML 19 435026112253101 43.841019 -112.446650 4,785 270 109–270 222 0–48 Basalt Domestic nd ML 22 434657112282201 43.782111 -112.473489 4,791 553 285–553 263 22–290 Basalt Monitoring 3.28 ML 23 434818112284801 43.804910 -112.480820 4,788 358 52–358 255 0–103 Basalt Irrigation nd
Tables 10–17 147

Table 11. Site information, including site name, U.S. Geological Survey site number, location, altitude, well depth, open interval, approximate depth to water, depth of open intervals below water table, aquifer material, water use, and hydraulic conductivity, Idaho National Laboratory and vicinity, eastern Idaho.—Continued

Site 

name

USGS site 

No.

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

Altitude of 

land surface 

(ft)

Depth 

of well 

(ft bls)

Extent of 

open 

intervals 

(ft bls)

Depth to 

water table 

(ft bls)

Depth of open 

intervals below 

water table 

(ft bwt)

Aquifer 

material

Water 

use

Estimated 

hydraulic 

conductivity 

(ft/d as log K)

Regional groundwater—Continued

ML 24 440001112290401 44.000279 -112.485361 4,810 125 110–125 62 48–63 Basalt Domestic nd

ML 25 440058112293605 44.016020 -112.494150 4,809 48 unk 32 <16 Basalt Irrigation nd

ML 26 440451112154601 44.146389 -112.510556 4,900 190 189–280 207 0–73 Basalt Domestic nd

ML 27 435003112313101 43.833972 -112.526333 4,785 660 366–396 213 153–183 Basalt Irrigation nd

ML 28 440328112314501 44.057685 -112.529989 4,817 214 156–214 85 71–129 Basalt Irrigation nd

ML 29 435402112332101 43.900460 -112.556650 4,784 207 unk 192 <15 Basalt Domestic nd

ML 30 435241112332401 43.878027 -112.557751 4,820 340 339–340 250 89–90 Basalt Domestic nd

ML 31 435951112335701 43.997418 -112.566667 4,831 247 115–247 99 16–148 Basalt Irrigation nd

ML 33 435831112365401 43.975333 -112.616167 4,801 298 255–298 211 44–87 Basalt Irrigation nd

ML 34 440226112402401 44.040000 -112.673889 4,950 480 unk 444 <36 Basalt Domestic nd

Reno Ranch 440142112425501 44.028240 -112.716106 5,110 540 unk 535 unk Alluvium Domestic nd

SE of Atomic City 432335112404801 43.392750 -112.679694 4,795 360 20–360 290 0–70 Basalt Domestic nd

USGS 3A 433732112335401 43.625465 -112.565819 5,179 733 689–740 673 16–67 Basalt Monitoring nd

USGS 101 433255112381801 43.548729 -112.639685 5,251 842 750–865 773 0–92 Basalt Monitoring 1.11

Geothermal water

INEL–1 2,000 feet 433717112563501 43.621312 -112.944212 4,873 10,333 1,511–2,206 310 1,201–1,896 Basalt Test hole -2.7 to -1.5

INEL–1 10,300 feet 433717112563501 43.621312 -112.944212 4,873 10,333 4,210–10,333 310 3,900–10,023 Basalt Test hole -2.7 to -1.5

ML 57 440832112331001 44.142129 -112.553602 5,260 unk unk unk unk Sandstone na nd

ML 58 441522112381901 44.256019 -112.639440 6,520 unk unk unk unk Limestone na nd

Groundwater at the Idaho National Laboratory

Deep groundwater

EBR 1 433051113002601 43.513698 -113.008156 5,024 1,075 600–1,075 586 14–489 Basalt Production 0.43

Site 9 433123112530101 43.522924 -112.884384 4,926 1,131 681–1,057 475 206–582 Basalt Monitoring >3.00

Site 14 434334112463101 43.726202 -112.776244 4,794 716 535–716 276 259–440 Basalt Monitoring 2.57

USGS 7 434915112443901 43.820688 -112.745235 4,789 903 241–840 214 27–626 Basalt Monitoring 1.38

USGS 15 434234112551701 43.709584 -112.922318 4,812 610 540–610 326 214–284 Basalt Monitoring 3.08

Contaminated groundwater

Advanced Test Reactor Complex

USGS 65 433447112574501 43.579587 -112.963923 4,925 498 456–498 468 0–30 Basalt Monitoring 2.45

Idaho Nuclear Technology and Engineering Center

CFA 1 433204112562001 43.534304 -112.939588 4,928 639 440–685 479 0–206 Basalt Production 1.08

CFA 2 433144112563501 43.528779 -112.943916 4,932 681 521–681 471 50–210 Basalt Production 1.04

USGS 20 433253112545901 43.547905 -112.917332 4,915 658 471–481 464 7–17 Basalt Monitoring 0.90

USGS 36 433330112565201 43.558271 -112.948461 4,929 567 430–567 475 0–92 Basalt Monitoring 3.61

USGS 57 433344112562601 43.562140 -112.941386 4,922 582 477–582 469 8–113 Basalt Monitoring 2.18
148 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho Table 11. Site information, including site name, U.S. Geological Survey site number, location, altitude, well depth, open interval, approximate depth to water, depth of open intervals below water table, aquifer material, water use, and hydraulic conductivity, Idaho National Laboratory and vicinity, eastern Idaho.—Continued Site name USGS site No. Latitude (decimal degrees) Longitude (decimal degrees) Altitude of land surface (ft) Depth of well (ft bls) Extent of open intervals (ft bls) Depth to water table (ft bls) Depth of open intervals below water table (ft bwt) Aquifer material Water use Estimated hydraulic conductivity (ft/d as log K) Contaminated groundwater—Continued Idaho Nuclear Technology and Engineering Center—Continued USGS 82 433401112551001 43.566832 -112.920368 4,907 693 470–700 452 18–248 Basalt Monitoring 3.00 USGS 85 433246112571201 43.546082 -112.954133 4,939 614 522–614 486 36–128 Basalt Monitoring 3.53 USGS 104 432856112560801 43.482149 -112.936423 4,988 700 550–700 558 0–142 Basalt Monitoring -1.03 USGS 105 432703113001801 43.450852 -113.005770 5,095 1,300 400–800 672 0–128 Basalt Monitoring 2.80 USGS 108 432659112582601 43.449572 -112.974813 5,031 1,196 400–760 611 0–149 Basalt Monitoring 2.98 USGS 109 432701113025601 43.450249 -113.049668 5,044 800 600–800 623 0–177 Basalt Monitoring 2.78 USGS 112 433314112563001 43.553935 -112.942702 4,928 507 432–563 476 0–87 Basalt Monitoring 2.83 USGS 113 433314112561801 43.553943 -112.939244 4,925 556 445–504 477 0–27 Basalt Monitoring 3.30 USGS 115 433320112554101 43.555524 -112.928994 4,919 581 440–581 467 0–114 Basalt Monitoring -0.58 USGS 116 433331112553201 43.558671 -112.926571 4,916 572 438–580 461 0–119 Basalt Monitoring 0.08 USGS 124 432307112583101 43.385145 -112.975335 5,102 800 750–800 686 64–114 Basalt Monitoring nd Naval Reactors Facility NRF 6 433910112550101 43.652809 -112.917778 4,846 417 359–417 373 0–44 Basalt Monitoring nd NRF 9 433840112550201 43.643270 -112.917722 4,853 422 372–422 380 0–42 Basalt Monitoring nd NRF 10 433841112545201 43.643787 -112.914244 4,854 427 377–427 380 0–47 Basalt Monitoring nd NRF 11 433847112544201 43.645298 -112.911733 4,852 417 362–417 377 0–40 Basalt Monitoring nd NRF 12 433855112543201 43.648207 -112.908386 4,851 425 375–425 377 0–48 Basalt Monitoring nd NRF 13 433928112545401 43.658968 -112.914522 4,842 425 371–421 368 3–53 Basalt Monitoring nd Radioactive Waste Management Complex RWMC M3S 433008113021801 43.502209 -113.039251 5,016 633 603–633 590 13–43 Basalt Monitoring nd RWMC M7S 433023113014801 43.506173 -113.030940 5,005 628 598–628 576 22–52 Basalt Monitoring nd RWMC Production 433002113021701 43.500462 -113.038887 5,005 685 590–685 568 22–117 Basalt Production 2.36 USGS 87 433013113024201 43.503445 -113.046126 5,018 673 585–640 587 0–53 Basalt Monitoring 0.99 USGS 88 432940113030201 43.494407 -113.051377 5,021 663 587–635 590 0–45 Basalt Monitoring -0.77 USGS 90 432954113020501 43.497809 -113.035793 5,010 626 577–626 583 0–43 Basalt Monitoring 1.20 USGS 120 432919113031501 43.488570 -113.054724 5,040 705 638–705 617 21–88 Basalt Monitoring 3.36 Test Area North TAN Disposal 435053112423201 43.847963 -112.709715 4,781 310 180–305 195 0–110 Basalt Disposal nd TDD 1 435042112420901 43.844907 -112.703326 4,800 315 75–315 206 0–109 Basalt Disposal nd TDD 2 435054112423201 43.848240 -112.709715 4,784 252 117–252 197 0–55 Basalt Disposal nd USGS 24 435053112420801 43.847343 -112.704254 4,795 326 255–325 220 35–105 Basalt Monitoring 2.30
Tables 10–17 149

Table 11. Site information, including site name, U.S. Geological Survey site number, location, altitude, well depth, open interval, approximate depth to water, depth of open intervals below water table, aquifer material, water use, and hydraulic conductivity, Idaho National Laboratory and vicinity, eastern Idaho.—Continued

Site 

name

USGS site 

No.

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

Altitude of 

land surface 

(ft)

Depth 

of well 

(ft bls)

Extent of 

open 

intervals 

(ft bls)

Depth to 

water table 

(ft bls)

Depth of open 

intervals below 

water table 

(ft bwt)

Aquifer 

material

Water 

use

Estimated 

hydraulic 

conductivity 

(ft/d as log K)

Natural groundwater

North INL Area

ANP 6 435152112443101 43.864232 -112.742880 4,794 295 211–296 220 9–76 Basalt Production 3.83ANP 8 434952112411301 43.831018 -112.687769 4,789 309 220–300 209 11–91 Basalt Production ndIET 1 Disposal 435153112420501 43.864735 -112.702276 4,790 242 219–319 214 5–105 Basalt Disposal 0.20No Name 1 435038112453401 43.844015 -112.759928 4,784 500 267–550 212 55–338 Basalt Monitoring -0.49PSTF Test 434941112454201 43.827890 -112.762344 4,786 319 190–316 214 0–102 Basalt Production 1.76TDD 3 435116112430301 43.854351 -112.718326 4,803 300 156–300 195 0–105 Basalt Disposal nd

Northeast INL Area

ANP 9 434856112400001 43.815382 -112.667591 4,786 322 237–314 227 10–87 Basalt Monitoring 2.54USGS 26 435212112394001 43.869504 -112.662141 4,789 267 232–267 214 18–53 Basalt Monitoring 4.38USGS 27 434851112321801 43.814136 -112.539402 4,784 312 250–308 229 21–79 Basalt Monitoring 1.20USGS 29 434407112285101 43.735148 -112.481441 4,877 426 363–425 359 4–66 Basalt Monitoring 3.15USGS 31 434625112342101 43.773769 -112.573173 4,786 428 285–428 259 26–169 Basalt Monitoring 2.08USGS 32 434444112322101 43.745484 -112.540052 4,812 392 306–392 294 12–98 Basalt Monitoring 3.81

Southeast INL Area

Arbor Test 1 433509112384801 43.585720 -112.647491 5,164 790 680–787 682 0–105 Basalt Production 3.75Area II 433223112470201 43.539525 -112.784826 5,129 876 676–876 673 3–203 Basalt Monitoring 2.88Atomic City 432638112484101 43.443798 -112.812214 5,017 639 35–639 587 0–52 Basalt Production ndLeo Rogers 1 432533112504901 43.425743 -112.847771 5,039 720 14–702 613 0–89 Basalt Stock ndUSGS 1 432700112470801 43.449932 -112.786530 5,022 630 600–630 590 10–40 Basalt Monitoring >4.04USGS 2 433320112432301 43.555428 -112.723402 5,125 699 675–695 662 13–33 Basalt Monitoring 3.26USGS 14 432019112563201 43.338596 -112.943029 5,133 752 720–723 717 3–6 Basalt Monitoring 2.78USGS 100 433503112400701 43.583998 -112.669342 5,158 750 662–750 678 0–72 Basalt Monitoring 2.26USGS 107 432942112532801 43.494913 -112.891808 4,918 690 270–690 482 0–208 Basalt Monitoring 2.52USGS 110A 432717112501502 43.454667 -112.838248 4,999 644 240–657 566 0–91 Basalt Monitoring nd

Central INL Area

Badging Facility well 433042112535101 43.511574 -112.898328 4,935 644 533–644 ~491 ~42–153 Basalt Production ndNPR Test 433449112523101 43.580305 -112.876179 4,933 600 500–535 467 33–68 Basalt Monitoring 2.38USGS 5 433543112493801 43.595116 -112.827952 4,938 494 475–497 471 4–26 Basalt Monitoring -0.30USGS 6 434031112453701 43.675219 -112.761009 4,899 620 532–620 417 115–203 Basalt Monitoring 0.66USGS 17 433937112515401 43.660024 -112.865904 4,833 498 438–498 359 79–139 Basalt Monitoring 0.65USGS 18 434540112440901 43.761213 -112.736740 4,804 329 298–322 275 23–47 Basalt Monitoring 3.26USGS 83 433023112561501 43.506305 -112.938407 4,941 752 516–752 501 15–251 Basalt Monitoring 0.58USGS 103 432714112560701 43.453678 -112.935976 5,007 1,297 575–760 586 0–174 Basalt Monitoring 2.94
150 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho Table 11. Site information, including site name, U.S. Geological Survey site number, location, altitude, well depth, open interval, approximate depth to water, depth of open intervals below water table, aquifer material, water use, and hydraulic conductivity, Idaho National Laboratory and vicinity, eastern Idaho.—Continued Site name USGS site No. Latitude (decimal degrees) Longitude (decimal degrees) Altitude of land surface (ft) Depth of well (ft bls) Extent of open intervals (ft bls) Depth to water table (ft bls) Depth of open intervals below water table (ft bwt) Aquifer material Water use Estimated hydraulic conductivity (ft/d as log K) Natural groundwater—Continued Northwest INL Area Fire Station 2 433548112562301 43.596573 -112.940553 4,902 510 427–511 420 7–91 Basalt Production nd INEL-1 WS 433716112563601 43.620612 -112.945248 4,872 490 340–595 401 0–194 Basalt Production 0.25 NRF 2 433854112545401 43.648234 -112.915858 4,850 528 373–448 375 0–73 Basalt Production nd NRF 7 433920112543601 43.656440 -112.909383 4,843 415 365–415 369 0–46 Basalt Monitoring nd NRF 8 433843112550901 43.644776 -112.920625 4,853 420 373–423 378 0–45 Basalt Monitoring nd Site 4 433617112542001 43.604907 -112.906385 4,795 495 422–497 401 21–96 Basalt Monitoring nd Site 17 434027112575701 43.674000 -112.966527 4,880 600 15–600 403 0–197 Basalt Monitoring 1.83 Site 19 433522112582101 43.589440 -112.973468 4,926 860 472–842 471 1–371 Basalt Monitoring 2.23 USGS 12 434126112550701 43.690514 -112.919470 4,819 563 unk 335 <228 Basalt Monitoring 2.00 USGS 19 434426112575701 43.740650 -112.966550 4,800 399 285–306 279 6–27 Basalt Monitoring 3.53 USGS 22 433422113031701 43.572761 -113.056692 5,048 657 619–657 614 5–43 Basalt Monitoring <-0.77 USGS 23 434055112595901 43.681892 -113.000839 4,884 458 410–430 405 5–25 Basalt Monitoring 3.64 USGS 97 433807112551501 43.635120 -112.922153 4,858 510 388–510 386 2–124 Basalt Monitoring 2.76 USGS 98 433657112563601 43.615740 -112.944164 4,883 508 400–500 415 0–85 Basalt Monitoring 2.92 USGS 99 433705112552101 43.617612 -112.923375 4,872 440 303–450 400 0–50 Basalt Monitoring 3.23 USGS 102 433853112551601 43.647370 -112.922061 4,850 445 359–445 378 0–67 Basalt Monitoring 2.40 USGS 134 433611112595819 43.603003 -113.000352 4,969 590 554–588 513 41–75 Basalt Monitoring nd Southwest INL Area Highway 3 433256113002501 43.548795 -113.007776 4,981 750 680–750 538 142–212 Basalt Domestic >0.52 Middle 2051 433217113004905 43.537943 -113.014548 4,997 999 564–610 571 0–39 Basalt Monitoring nd USGS 8 433121113115801 43.522269 -113.200122 5,195 812 782–812 770 12–42 Basalt Monitoring 2.84 USGS 9 432740113044501 43.458901 -113.078549 5,030 654 618–654 610 8–44 Basalt Monitoring 3.32 USGS 11 432336113064201 43.393290 -113.112645 5,067 704 673–704 655 18–49 Basalt Monitoring >3.36 USGS 86 432935113080001 43.492903 -113.134568 5,077 691 48–691 652 0–39 Basalt Monitoring 0.81 USGS 89 433005113032801 43.501481 -113.059646 5,030 637 576–646 604 0–42 Basalt Monitoring -0.06 USGS 117 432955113025901 43.498379 -113.050463 5,012 655 550–655 588 0–67 Basalt Monitoring -0.72 USGS 119 432945113023401 43.495632 -113.043524 5,032 705 639–705 685 0–20 Basalt Monitoring -2.00 USGS 125 432602113052801 43.433076 -113.092603 5,051 774 620–774 630 0–144 Basalt Monitoring nd USGS 135 432753113093613 43.464759 -113.160730 5,136 861 727–762 719 8–43 Basalt Monitoring nd
Tables 10–17 151

Table 12. Measurements of field parameters and helium and the calculated partial pressure of carbon dioxide, Idaho National Laboratory and vicinity, eastern Idaho.[Data from Busenberg and others (2000), Rattray (2015), Knobel and others (1992, 1999a, 1999b), U.S. Geological Survey National Water Information System (2014), Swanson and others (2002, 2003), Carkeet and others (2001), Bartholomay and Twining (2010), Bartholomay and others (2015), and Mann (1986). Springs are shown in italics. Locations of sites shown in figures 8–9. Site name: Alternate names used in other reports shown in table 10. Alkalinity: Concentrations for data from Busenberg and others (2000) and Knobel and others (1992) were calculated from bicarbonate concentrations using the equation in Hem (1992). Dissolved oxygen (DO): Values preceded by a ≈ symbol indicate that no measurement of DO was made on the date shown and that the DO value was estimated as the mean value of all DO measurements for that site in NWIS through December 2015. Carbon dioxide: Calculated with PHREEQC (Parkhurst and Appelo, 2013). Abbreviations: cm3 STP/g, cubic centimeters per gram at 0 °C and one atmosphere; INL, Idaho National Laboratory; mg/L, milligram per liter; μS/cm at 25 °C, microsiemens per centimeter at 25 degrees Celsius; nd, not determined; sz, shallowest zone. Units: pH, negative base-10 logarithm of the hydrogen ion activity; Log PCO2, base-10 logarithm of carbon dioxide partial pressure. Symbols: °C, degrees Celsius; <, less than]

Site name Date sampled Temperature (°C) pH Specific conductance (μS/cm at 25 °C) Alkalinity (mg/L as CaCO3) Dissolved oxygen (mg/L) Carbon dioxide (Log PCO2) Helium ([cm3 STP/g] × 10-8)

Surface water

Big Lost River at Mackay Dam 06-28-1995 13.1 8.2 nd 89 ≈10.3 -3.2 ndBig Lost River at bridge near Mackay 06-17-1995 11.0 8.1 299 86 ≈8.5 -3.2 ndBig Lost River near Arco 06-05-1981 13 8.1 374 164 8.8 -2.9 ndBig Lost River below INL Diversion 06-02-1995 15 8.4 262 108 7.2 -3.4 ndBig Lost River near Atomic City 10-01-1965 6 8.2 356 171 nd -3.0 ndBig Lost River below lower Lincoln Blvd Br 06-19-1995 12.5 7.7 1337 101 nd -2.7 nd

Birch Creek at Kaufman Guard Station 06-27-2000 16.5 8.6 320 134 10.0 -3.5 ndBirch Creek at Blue Dome 06-28-1995 9.4 8.5 2326 165 ≈9.2 -3.3 ndCamas Creek below diversion near CNWR 08-08-2011 19.3 7.8 147 76 5.8 -2.9 ndLittle Lost River near Clyde 06-27-2000 12.0 8.4 245 107 9.1 -3.4 ndLittle Lost River near Howe 06-28-1995 14.1 8.1 3324 98 ≈9.2 -3.1 ndMud Lake near Terreton 06-17-1995 14.7 8.5 276 103 ≈8.4 -3.5 nd

Tributary valley groundwater

Big Lost River Valley

Arco City Well 4 05-13-1997 9.6 8.0 392 175 6.3 -2.8 6.2

Coates 06-01-1999 6.5 7.2 180 73 8.1 -2.3 ndFulton 06-02-1999 7.9 7.5 534 243 9.2 -2.1 ndHill 06-02-1999 8.9 8.0 238 101 9.6 -3.0 ndLambert 06-03-1999 8.7 7.6 389 175 3.6 -2.4 ndMSR 06-01-1999 7.3 8.0 231 99 7.2 -3.0 ndMuffett 06-03-1999 10.3 7.4 486 221 8.2 -2.1 ndOwen 06-23-1999 9.5 7.6 458 199 6.1 -2.3 ndWheeler 06-02-1999 9.6 7.6 483 206 6.8 -2.3 ndWildhorse Guard Station 06-02-1999 7.1 8.0 342 158 <0.2 -2.8 nd

Little Lost River Valley

Harrell 07-31-2000 10.5 7.4 557 213 8.3 -2.1 nd

Mays 06-26-2000 15.0 7.9 290 128 7.1 -2.8 ndNicholson 07-31-2000 11.0 7.6 964 184 7.2 -2.4 ndOar 06-28-2000 8.5 7.8 346 157 7.4 -2.6 ndPancheri 05-13-1997 8.2 8.0 359 153 8.2 -2.8 10.0Ruby Farms 05-10-1991 10.0 7.9 550 167 9.6 -2.7 ndSorenson 07-31-2000 7.0 8.0 255 125 7.3 -2.9 nd
152 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho Table 12. Measurements of field parameters and helium and the calculated partial pressure of carbon dioxide, Idaho National Laboratory and vicinity, eastern Idaho.—Continued Site name Date sampled Temperature (°C) pH Specific conductance (μS/cm at 25 °C) Alkalinity (mg/L as CaCO3

)

Dissolved 

oxygen 

(mg/L)

Carbon dioxide 

(Log PCO2

)

Helium 

([cm3 STP/g] × 10-8)

Birch Creek Valley

Kaufman Guard Station 06-27-2000 11.0 8.1 373 193 <0.2 -2.8 ndMcKinney 06-13-1991 8.0 7.9 352 149 5.4 -2.7 ndP&W2 04-19-1995 9.5 8.2 340 140 9.7 -3.1 4.1USGS 126b 11-08-2000 10.5 8.2 344 133 10.3 -3.1 ndWagoner 05-22-1997 7.0 7.8 376 173 nd -2.6 6.3Wagoner Ranch 06-28-2000 11.0 7.6 443 182 8.4 -2.3 nd

Beaverhead Mountains

ML 55 06-05-2012 12.8 7.8 338 138 7.7 -2.7 ndML 59 06-05-2012 7.3 7.4 258 124 8.6 -2.4 nd

Regional groundwater

Highway 2 10-16-1952 12.0 7.8 275 120 nd -2.7 ndKettle Butte Farms 06-29-1995 11.7 8.1 341 137 ≈8.8 -3.0 ndML 2 07-30-2007 13.2 7.7 311 117 7.2 -2.6 ndML 5 08-09-2011 14.4 7.9 292 110 8.3 -2.8 ndML 6 08-08-2011 12.1 8.3 249 112 8.1 -3.3 ndML 9 08-23-2011 12.9 7.6 370 151 ≈5.9 -2.4 ndML 12 08-09-2011 12.8 7.8 301 136 4.8 -2.7 ndML 13 07-30-2008 13.2 7.7 313 124 7.8 -2.6 ndML 15 06-19-2007 12.1 7.6 293 114 7.8 -2.5 ndML 18 09-23-2009 13.2 7.9 265 110 9.5 -2.8 ndML 17 06-04-2012 9.0 7.8 344 117 8.1 -2.7 ndML 19 05-14-1997 11.0 7.7 722 230 nd -2.4 7.2ML 22 10-15-1996 11.0 7.8 727 279 7.7 -2.4 4.8ML 23 08-29-1989 14.6 7.9 613 184 nd -2.6 ndML 24 06-06-2012 10.5 7.3 929 272 6.9 -1.9 ndML 25 06-11-1991 12.5 8.1 282 127 0.1 -3.0 41.8ML 26 09-06-2006 11.6 7.4 489 198 11.1 -2.1 ndML 27 06-26-2008 17.7 8.2 307 119 3.4 -3.1 ndML 28 07-06-2006 11.2 7.6 557 166 9.3 -2.4 ndML 29 06-12-1991 12.5 8.5 335 156 0.7 -3.3 ndML 30 06-06-2012 12.9 7.4 848 384 7.4 -1.8 ndML 31 06-06-2012 11.2 7.3 692 244 4.5 -1.9 ndML 33 07-17-2002 12.2 7.3 1,100 186 8.3 -2.0 ndML 34 09-04-2001 16.4 7.6 502 157 7.8 -2.4 ndReno Ranch 06-28-2000 14.0 7.6 481 190 6.4 -2.3 ndSE of Atomic City 06-27-1995 14.3 8.1 277 114 ≈7.9 -3.0 ndUSGS 3A 10-22-1952 13.0 8.0 276 122 nd -2.9 ndUSGS 101 10-10-1996 13.9 8.2 282 120 7.2 -3.1 10.2
Tables 10–17 153

Table 12. Measurements of field parameters and helium and the calculated partial pressure of carbon dioxide, Idaho National Laboratory and vicinity, eastern Idaho.—Continued

Site name Date sampled Temperature (°C) pH Specific conductance (μS/cm at 25 °C) Alkalinity (mg/L as CaCO3) Dissolved oxygen (mg/L) Carbon dioxide (Log PCO2) Helium ([cm3 STP/g] × 10-8)

Geothermal water

INEL-1 2,000 feet 03-24-1979 34 8.2 4645 210 5oxic -2.8 ndINEL-1 10,300 feet 07-20-1979 57 7.9 41,878 740 5anoxic -1.8 ndML 57 11-27-2000 48.4 7.2 694 138 5.9 -1.8 120ML 58 06-05-2012 27.8 7.1 430 166 1.8 -1.8 nd

Groundwater at the Idaho National Laboratory

Deep groundwater

EBR 1 10-16-1996 18.8 8.2 279 116 6.7 -3.1 5.5

Site 9 07-22-1996 13.7 8.1 350 139 6.8 -3.0 12.7Site 14 10-14-1996 16.3 8.0 341 131 6.8 -2.9 38.4USGS 7 10-14-1996 18.8 8.1 300 122 3.9 -3.0 149USGS 15 06-14-1995 11.6 8.0 319 137 ≈6.4 -2.9 23.0

Contaminated groundwater

Advanced Test Reactor Complex

USGS 65 05-16-1991 14.0 8.0 600 123 8.6 -2.9 nd

Idaho Nuclear Technology and Engineering Center

CFA 1 07-16-1996 12.3 7.9 567 131 9.5 -2.8 6.2

CFA 2 07-16-1996 12.1 7.9 745 122 8.4 -2.8 5.2USGS 20 05-30-1991 13.0 8.0 348 120 8.6 -2.9 ndUSGS 36 07-16-1996 12.6 8.0 489 163 ≈8.3 -2.8 4.5USGS 57 05-13-1991 14.5 7.8 690 121 8.3 -2.7 ndUSGS 82 07-16-1996 12.3 8.1 343 125 9.1 -3.0 5.6USGS 85 06-04-1991 13.0 8.0 518 153 9.0 -2.8 ndUSGS 104 07-15-1996 12.3 8.1 327 128 9.0 -3.0 11.5USGS 105 04-18-1995 13.7 8.1 384 148 9.5 -2.9 5.3USGS 108 04-19-1995 12.8 8.1 358 135 8.7 -3.0 ndUSGS 109 10-11-1996 13.6 8.1 375 148 7.7 -2.9 4.6USGS 112 07-15-1996 13.6 8.0 839 142 6.6 -2.9 5.4USGS 113 07-16-1996 13.1 8.0 1,063 135 9.0 -2.9 5.4USGS 115 07-15-1996 13.3 8.1 407 120 8.4 -3.0 6.9USGS 116 07-15-1996 12.7 8.2 580 100 9.2 -3.2 6.2USGS 124 10-09-1996 13.6 8.0 367 144 ≈7.4 -2.8 6.2

Naval Reactors Facility

NRF 6 09-05-1996 11.5 7.8 1,480 173 ≈8.4 -2.6 ndNRF 9 09-04-1996 11.5 8.1 647 205 ≈8.3 -2.8 ndNRF 10 09-04-1996 11.5 8.1 608 200 ≈7.6 -2.8 nd
154 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho Table 12. Measurements of field parameters and helium and the calculated partial pressure of carbon dioxide, Idaho National Laboratory and vicinity, eastern Idaho.—Continued Site name Date sampled Temperature (°C) pH Specific conductance (μS/cm at 25 °C) Alkalinity (mg/L as CaCO3

)

Dissolved 

oxygen 

(mg/L)

Carbon dioxide 

(Log PCO2

)

Helium 

([cm3 STP/g] × 10-8)

Naval Reactors Facility—Continued

NRF 11 09-05-1996 11.5 8.0 631 198 ≈7.8 -2.7 ndNRF 12 09-05-1996 11.5 8.0 684 201 ≈8.0 -2.7 ndNRF 13 09-05-1996 16.5 8.5 540 93 ≈7.3 -3.5 nd

Radioactive Waste Management Complex

RWMC M3S 07-22-1996 13.7 8.1 368 144 ≈7.4 -2.9 6.4RWMC M7S 07-22-1996 13.8 8.2 351 141 ≈6.4 -3.0 5.6RWMC Production 03-23-1989 13.0 8.1 358 148 8.2 -2.9 ndUSGS 87 04-05-1989 14.0 8.1 360 111 10.2 -3.0 ndUSGS 88 04-04-1989 14.0 8.2 600 93 8.5 -3.2 ndUSGS 90 04-05-1989 13.5 8.1 383 120 9.6 -3.0 ndUSGS 120 07-17-1996 12.0 8.2 444 153 10.2 -3.0 4.9

Test Area North

TAN Disposal 03-07-1989 15.0 8.0 945 229 <0.2 -2.6 ndTDD 1 03-02-1989 11.0 8.0 525 122 2.4 -2.9 ndTDD 2 03-06-1989 12.5 7.9 820 194 4.2 -2.6 ndUSGS 24 02-28-1989 11.0 8.0 645 176 6.3 -2.8 nd

Natural groundwater

North INL Area

ANP 6 07-19-1996 13.3 8.0 407 148 8.3 -2.8 5.9ANP 8 12-13-1989 10.0 8.2 376 127 10.5 -2.9 ndIET 1 Disposal 07-18-1996 14.0 7.9 427 155 0.7 -2.7 6.1No Name 1 10-14-1996 10.4 8.1 346 114 12.2 -3.1 9.7PSTF Test 10-14-1996 13.3 8.2 301 135 ≈8.2 -3.1 5.9TDD 3 12-13-1989 9.5 7.8 400 127 9.2 -2.5 nd

Northeast INL Area

ANP 9 10-14-1996 13.9 8.1 378 145 7.5 -2.9 15.8USGS 26 10-15-1996 14.9 8.0 391 151 7.6 -2.8 27.7USGS 27 10-15-1996 15.5 8.0 568 140 5.3 -2.9 32.4USGS 29 06-15-1995 12.7 8.0 432 157 7.4 -2.8 16.3USGS 31 07-19-1996 15.8 8.0 405 133 7.3 -2.9 20.6USGS 32 06-15-1995 14.6 7.9 506 134 8.0 -2.8 6.1

Southeast INL Area

Arbor Test 1 10-10-1996 13.5 8.0 348 133 8.3 -2.9 8.4Area II 07-18-1996 14.3 8.1 364 139 ≈7.7 -2.9 15.5Atomic City 10-09-1996 14.2 8.2 356 138 ≈7.9 -3.1 5.2Leo Rogers 1 07-17-1996 14.5 8.1 370 140 ≈7.2 -2.9 6.7
Tables 10–17 155

Table 12. Measurements of field parameters and helium and the calculated partial pressure of carbon dioxide, Idaho National Laboratory and vicinity, eastern Idaho.—Continued

Site name Date sampled Temperature (°C) pH Specific conductance (μS/cm at 25 °C) Alkalinity (mg/L as CaCO3) Dissolved oxygen (mg/L) Carbon dioxide (Log PCO2) Helium ([cm3 STP/g] × 10-8)

Natural groundwater—Continued

Southeast INL Area—Continued

USGS 1 10-09-1996 14.6 8.2 316 130 7.9 -3.1 10.9USGS 2 07-17-1996 13.9 8.1 353 136 8.0 -3.0 6.4USGS 14 10-09-1996 14.7 8.2 387 138 5.1 -3.1 4.8USGS 100 04-21-1995 13.5 8.1 383 135 9.5 -3.0 9.8USGS 107 10-09-1996 14.9 8.1 399 144 9.1 -2.9 7.0USGS 110A 10-09-1996 14.8 8.1 378 142 ≈6.3 -2.9 9.7

Central INL Area

Badging Facility well 07-16-1996 12.1 8.1 354 133 ≈8.2 -3.0 4.0NPR Test 10-10-1996 12.2 8.1 385 160 9.2 -2.9 5.7USGS 5 10-10-1996 14.9 8.1 331 139 ≈6.6 -2.9 6.9USGS 6 07-18-1996 14.1 8.1 299 120 ≈5.6 -3.0 11.7USGS 17 06-13-1995 13.5 8.2 298 124 8.8 -3.1 9.1USGS 18 07-19-1996 15.6 8.0 345 138 ≈5.8 -2.8 28.8USGS 83 04-11-1995 11.8 8.2 282 101 6.1 -3.2 ndUSGS 103 07-15-1996 13.9 8.3 363 137 8.7 -3.2 5.0

Northwest INL Area

Fire Station 2 10-16-1996 11.3 8.0 447 167 9.1 -2.8 4.6INEL-1 WS 06-12-1995 12.5 7.9 621 160 11.4 -2.7 ndNRF 2 05-23-1989 12.5 7.7 680 213 9.0 -2.4 ndNRF 7 09-03-1996 17.0 8.5 236 106 ≈7.0 -3.5 ndNRF 8 09-04-1996 11.5 8.0 595 214 ≈8.2 -2.7 ndSite 4 10-16-1996 11.3 8.1 369 157 ≈7.5 -2.9 5.9Site 17 06-16-1995 12.3 7.9 414 180 8.1 -2.6 ndSite 19 07-16-1996 15.2 8.0 387 164 8.1 -2.8 4.7USGS 12 06-14-1995 12.0 7.8 602 214 ≈8.0 -2.5 4.3USGS 19 10-15-1996 16.9 7.8 396 168 6.9 -2.5 6.1USGS 22 06-13-1995 620.0 7.9 410 71 ≈2.2 -3.0 4.7USGS 23 04-19-1995 15.4 7.9 357 149 7.5 -2.7 9.2USGS 97 06-13-1995 11.5 7.9 597 221 9.2 -2.6 4.6USGS 98 06-12-1995 12.3 8.0 430 171 10.1 -2.8 5.5USGS 99 06-12-1995 11.8 7.9 528 203 8.6 -2.6 4.5USGS 102 06-13-1995 11.6 7.9 590 217 ≈8.3 -2.6 4.7USGS 134 (sz) 09-04-2008 12.9 7.9 313 128 10.0 -2.8 nd
156 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho Table 12. Measurements of field parameters and helium and the calculated partial pressure of carbon dioxide, Idaho National Laboratory and vicinity, eastern Idaho.—Continued Site name Date sampled Temperature (°C) pH Specific conductance (μS/cm at 25 °C) Alkalinity (mg/L as CaCO3

)

Dissolved 

oxygen 

(mg/L)

Carbon dioxide 

(Log PCO2

)

Helium 

([cm3 STP/g] × 10-8)

Natural groundwater—Continued

Southwest INL Area

Highway 3 10-12-1984 14.7 8.3 343 151 9.2 -3.1 ndMiddle 2051 (sz) 08-25-2008 10.5 7.5 346 154 10.5 -2.3 ndUSGS 8 10-08-1996 11.4 8.0 376 165 8.0 -2.8 4.3USGS 9 10-11-1996 11.4 8.2 396 141 8.2 -3.1 6.3USGS 11 04-20-1995 11.7 8.1 366 142 8.2 -3.0 5.1USGS 86 10-11-1996 10.0 8.3 332 109 11.4 -3.3 7.4USGS 89 07-17-1996 13.1 8.6 385 84 11.6 -3.7 6.1USGS 117 07-17-1996 13.4 8.3 277 99 7.0 -3.3 6.3USGS 119 04-03-1989 15.0 8.3 298 94 8.4 -3.3 ndUSGS 125 06-16-1995 12.8 8.0 379 146 ≈6.9 -2.8 5.0USGS 135 (sz) 09-14-2010 11.6 7.9 330 136 6.6 -2.8 nd

1Specific conductance measurement from 1996.2Specific conductance measurement from 04-14-1995.3Specific conductance measurements from 10-17-1995.4Specific conductance was estimated by dividing the dissolved solids concentration by 0.543 (Olmsted, 1962).5These geothermal waters were assumed to be oxic or anoxic based on their concentrations of uranium and iron.6The temperature of 20.0 °C measured from well USGS 22 may not reflect the ambient groundwater temperature at this well. The estimated hydraulic conductivity for this well was small (log K of 

<-0.77 ft/d; table 11), the well pumps slowly (about 2.5 gal/min), and the groundwater temperature in the well increases with increased pumping time. These factors indicate that heat from the pump motor warms the water in this well during pumping. The initial water pumped from this well during each site visit has a temperature of about 15 °C, and this temperature probably represents the ambient groundwater temperature at this well.
Tables 10–17 157

Table 13. Concentrations of major ions, silica, and the charge balance for each water-quality analysis, Idaho National Laboratory and vicinity, eastern Idaho.[Data from Busenberg and others (2000); Rattray (2015); Knobel and others (1992, 1999a, 1999b); Swanson and others (2002, 2003); Carkeet and others (2001); Bartholomay and Twining (2010); Bartholomay and others (2015); Mann (1986); Johnson and others (2000); and U.S. Geological Survey (2014). Springs are shown in italics; All concentrations except nitrate are in milligrams per liter, nitrate (nitrite plus nitrate) in milligrams per liter as nitrogen. Location of sites shown on figures 8–9. Site name: Alternate names used in other reports shown in table 10. Bicarbonate: Concentrations from Busenberg and others (2000) were calculated from alkalinity using the equation in Hem (1992). Carbonate: Concentrations calculated with PHREEQC (Parkhurst and Appelo, 2013). Sulfate: Values in parantheses indicate a sulfate concentration was reported for anoxic water. Abbreviations: INL, Idaho National Laboratory; nc, not calculated; nd, not determined; sz, shallowest zone; <, less than]

Site name Calcium Magnesium Sodium Potassium Bicarbonate Carbonate Chloride Sulfate Fluoride Nitrate Silica

Charge 

balance

(percent)

Surface water

Big Lost River at Mackay Dam 26.1 6.3 3.8 1.3 108 0.69 2.3 13.1 0.19 nd 8.7 -2.9Big Lost River at bridge near Mackay 25.9 6.3 3.8 1.4 105 0.50 2.3 12.6 0.18 0.1 9.1 -1.7Big Lost River near Arco 48 12 7.1 1.6 200 1.06 4.8 27 0.2 0.1 13 -3.8Big Lost River below INL Diversion 35 8 5.4 1.4 132 1.40 3 18 0.2 <0.05 12 1.7Big Lost River near Atomic City1 46.7 11.4 6.6 1.3 208 1.12 5 nd 0.3 nd 5.2 ndBig Lost River below lower Lincoln Blvd Br 31.2 7.4 4.8 1.7 123 0.25 3.1 17.5 0.21 0.2 10.7 -1.7Birch Creek at Kaufman Guard Station 38 15 5.1 0.9 163 2.81 4.6 23 0.22 0.1 10 2.7Birch Creek at Blue Dome 41.9 15.1 5.2 0.9 201 2.35 4.8 25.3 0.18 0.2 7.7 -4.2Camas Creek below diversion near CNWR 19 4.7 3.6 2.0 91 0.27 1.0 1.4 0.11 <0.02 18 -0.7Little Lost River near Clyde 30 10 2.8 0.6 130 1.28 2.2 11.4 0.12 <0.05 9.2 0.8Little Lost River near Howe 26.8 8.7 4.0 1.2 120 0.63 3.8 8.5 0.10 0.1 10.1 -0.6Mud Lake near Terreton 28.4 6.5 5.2 2.1 125 1.55 2.5 4.3 0.12 30.25 14.7 -1.2

Tributary valley groundwater

Big Lost River Valley

Arco City Well 4 53.5 13.5 5.4 1.0 209 0.83 6.5 19.9 0.20 0.6 13.4 -0.8Coates 24 5.2 3.1 0.6 89 0.05 1.6 12 0.18 0.1 8.7 0.2Fulton 74 24 3.6 1.3 296 0.36 9.5 21 0.32 1.8 15 1.2Hill 29 6.0 8.3 1.0 123 0.45 2.8 14 0.20 0.2 13 -2.1Lambert 52 12 5.8 1.3 213 0.32 4.5 19 0.24 0.3 12 -2.4MSR 33 7.6 3.9 0.9 121 0.42 2.7 13 0.15 0.2 14 2.1Muffett 65 21 9.8 1.2 269 0.28 7.7 20 0.41 0.8 20 2.8Owen 68 14 7.4 1.2 243 0.38 6.3 23 0.19 2.1 16 0.9Wheeler 66 15 9.9 1.2 251 0.40 7.5 26 0.18 1.6 14 -0.1Wildhorse Guard Station 42 15 7.7 1.2 193 0.68 2.6 4(17) 0.21 <0.05 12 0.9

Little Lost River Valley

Harrell 63 22 17 1.3 259 0.27 21.6 34.4 0.16 1.9 19 0.0Mays 28 13 12 1.4 156 0.54 5.6 15.0 0.14 0.4 21 -0.9Nicholson 85 45 27 1.8 225 0.39 143 60.3 <0.1 4.2 23 -0.7Oar 40 15 5.7 0.9 191 0.45 6.2 10.5 <0.1 0.5 14 -1.1Pancheri 43.6 14.5 5.8 0.9 186 0.69 10.1 15.5 0.15 0.4 14.0 -1.0Ruby Farms 62 23 14 1.6 204 0.65 50 32 <0.1 2.9 19 -0.2Sorenson 32 11 4 0.9 153 0.53 2.6 5.0 0.13 0.2 17 -0.5
158 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho Table 13. Concentrations of major ions, silica, and the charge balance for each water-quality analysis, Idaho National Laboratory and vicinity, eastern Idaho.—Continued Site name Calcium Magnesium Sodium Potassium Bicarbonate Carbonate Chloride Sulfate Fluoride Nitrate Silica Charge balance (percent) Tributary Valley groundwater—Continued Birch Creek Valley Kaufman Guard Station 29 24 12 5.2 235 1.18 3.2 4(3.9) 0.58 <0.05 62 -0.2 McKinney 45 15 5.4 1.0 182 0.53 5.4 26 0.2 0.3 10 0.2 P&W2 38.0 14.3 7.5 1.2 171 1.02 5.5 25.8 0.19 0.3 12.1 -1.9 USGS 126b 38 15 8.7 2.3 162 1.00 8.2 29 0.23 0.5 18 -0.1 Wagoner 48.6 15.8 5.1 1.1 201 0.48 5.5 21.9 0.22 0.2 11.9 0.4 Wagoner Ranch 46 19 17 1.1 222 0.36 9.6 29 0.19 0.4 10 0.7 Beaverhead Mountains ML 55 46.9 7.7 11.4 2.9 164 0.45 15.8 15.9 0.43 0.9 29 -0.3 ML 59 39.0 8.9 3.2 0.7 149 0.13 3.4 9.3 0.10 0.7 8 0.8 Regional groundwater Highway 2 26 9.3 18.0 2.3 140 0.37 8.2 13 0.9 0.4 32 0.3 Kettle Butte Farms 36 10 15 2.9 167 0.84 11 14 1 1.0 35 -2.1 ML 2 31.5 9.5 14.5 2.7 140 0.30 7.7 14.0 0.89 3.2 37 -0.6 ML 5 29.8 10.3 10.8 2.7 131 0.46 15.0 12.7 0.25 0.7 34 -0.7 ML 6 29.9 8.3 9.0 2.4 131 1.07 5.6 9.3 0.49 1.7 34 -1.1 ML 9 41.0 11.8 14.9 2.7 181 0.31 12.3 13.8 0.48 2.1 34 -0.7 ML 12 31.8 9.6 13.2 2.9 162 0.43 9.5 9.1 0.41 1.0 34 -3.1 ML 13 32.1 9.3 14.8 2.9 148 0.32 8.8 11.7 1.01 2.5 37 -1.2 ML 15 27.7 9.6 17.6 3.1 137 0.23 12.6 10.9 0.54 1.2 34 1.1 ML 17 37.2 11.7 14.7 3.8 140 0.34 25.7 16.1 0.53 1.3 46 0.9 ML 18 28.0 8.6 11.9 2.8 132 0.44 9.8 8.9 0.45 1.5 35 -1.5 ML 19 68.7 28.6 38.2 5.8 281 0.60 55.0 42.1 0.19 5.3 32 1.0 ML 22 68.9 26.0 37.9 6.8 340 0.92 40.4 31.9 0.21 4.9 28 -2.4 ML 23 42 14 56 6.5 218 0.81 43 30 0.40 4.1 29 0.8 ML 24 109 33.0 47.3 5.4 322 0.29 93.0 91.3 0.16 2.9 34 1.6 ML 25 22 4.6 28 4.8 151 0.79 6.8 7(8.3) 0.90 0.1 48 -1.7 ML 26 65.2 16.1 12.7 3.5 237 0.26 16.2 36.9 0.36 1.5 35 -0.2 ML 27 14.6 6.3 37.2 6.8 140 1.06 12.7 17.2 0.64 0.1 33 -0.8 ML 28 67.1 16.7 15.7 4.1 202 0.34 47.5 39.5 0.25 1.7 37 -0.9 ML 29 19 17 23 4.3 181 2.40 10 9.8 0.50 0.1 29 -1.5 ML 30 74.6 26.7 85.0 7.2 468 0.55 36.1 29.3 0.15 8.5 27.5 -0.7 ML 31 75.0 20.7 51.6 4.8 291 0.26 46.2 52.8 0.22 4.4 37 2.0 ML 33 113 37.8 39.7 7.3 226 0.21 166 86.3 0.28 5.5 37.3 0.3 ML 34 41.9 15.1 40.0 3.4 192 0.37 24.1 59.4 0.54 1.5 35.6 -0.5 Reno Ranch 49 24 12 2.9 232 0.41 12.0 34.0 1.5 0.6 41 0.3 SE of Atomic City 26.0 8.8 14 2.7 139 0.74 7.5 10 1.20 0.6 36 -2.3 USGS 3A 29.0 9.5 15 2.7 148 0.61 8.0 9.1 0.90 0.3 34 0.0 USGS 101 28.8 9.2 12.9 2.8 148 0.97 8.5 9.0 0.78 0.8 33.6 -2.7
Tables 10–17 159

Table 13. Concentrations of major ions, silica, and the charge balance for each water-quality analysis, Idaho National Laboratory and vicinity, eastern Idaho.—Continued

Site name Calcium Magnesium Sodium Potassium Bicarbonate Carbonate Chloride Sulfate Fluoride Nitrate Silica

Charge 

balance

(percent)

Geothermal water

INEL-1 2,000 feet 10 2.0 92 10 220 2.67 17 32 1.1 nd 60 0.2INEL-1 10,300 feet 7.3 0.5 390 7.5 900 7.19 12 4(99) 13 nd 47 -1.4

ML 57 87.1 16.0 26.4 13.6 168 0.24 6.7 191 7.0 <0.05 34 -1.0ML 58 53.3 19.7 9.9 2.9 198 0.16 5.2 58.0 0.94 0.1 16.7 1.3

Groundwater at the Idaho National Laboratory

Deep groundwater

EBR 1 22.6 15.3 8.0 3.1 144 1.06 7 15.7 0.19 0.4 33.8 -2.4

Site 9 35.7 14.7 11.2 2.8 166 0.91 13.1 22.9 0.28 0.6 23.7 -1.5Site 14 34.0 13.3 12.9 3.0 165 0.73 9.5 23.4 0.41 0.6 29.7 -1.7USGS 7 24.6 9.3 20.8 4.4 142 0.89 9.1 16.1 1.30 0.4 47.1 -0.6USGS 15 32.7 15.3 8.9 1.6 167 0.67 7.0 18.5 0.11 0.4 18.0 -0.9

Contaminated groundwater

Advanced Test Reactor Complex

USGS 65 85.0 19 14 3.0 150 0.68 21 150 <0.1 1.6 21.0 1.4

Idaho Nuclear Technology and Engineering Center

CFA 1 61.6 18.6 14.4 3.2 160 0.54 74.0 27.7 0.25 3.5 20.9 -2.3CFA 2 71.9 26.4 21.4 4.3 149 0.51 115 45.0 0.39 3.7 23.6 -0.9USGS 20 41.0 12 8.0 2.6 146 0.61 21 22 0.20 1.0 23.0 -1.4USGS 36 60.9 15.4 16.7 2.8 199 0.85 33.9 27.7 0.22 1.8 19.3 1.4USGS 57 67.0 18 41 3.6 148 0.43 110 35 0.30 3.7 23.0 1.1USGS 82 35.7 13.4 10.4 3.0 152 0.79 18 21 0.21 0.5 22.6 -1.4USGS 85 57.0 14 22 2.9 187 0.81 46 31 0.20 2.5 21.0 -1.9USGS 104 34.9 13.7 7.6 2.4 156 0.80 12.6 19.3 0.20 0.7 24.7 -2.1USGS 105 40.8 15.2 12.7 2.8 180 0.98 13.6 26.0 0.19 0.7 21.2 -0.7USGS 108 37.0 15.0 10.6 2.4 165 0.86 14.0 22.4 0.24 0.7 23.3 -0.7USGS 109 39.8 15.7 10.5 2.7 181 0.97 14.0 25.0 0.23 0.6 24.4 -2.1USGS 112 76.0 21.0 54.0 4.9 173 0.79 151 29.0 0.26 3.2 21.5 0.2USGS 113 78.3 23.1 78.4 6.2 164 0.76 218 31.2 0.15 2.4 21.5 -1.6USGS 115 42.9 13.3 13.2 3.3 146 0.78 38.0 21.2 0.23 1.3 21.5 -1.8USGS 116 56.4 16.0 24.8 4.6 122 0.82 89.3 34.2 0.30 3.0 22.2 -1.5USGS 124 38.6 16.2 8.8 2.4 176 0.75 14.8 21.5 0.30 0.7 25.7 -1.8

Naval Reactors Facility

NRF 6 130 35 110 4.4 211 0.62 240 200 0.10 1.7 nd -0.9

NRF 9 73 24 17 2.4 250 1.33 48 49 nd 2.2 nd -1.9NRF 10 72 25 16 2.4 244 1.30 43 44 nd 1.8 nd 0.8NRF 11 72 23 19 2.8 241 1.02 44 50 nd 1.9 nd -0.1NRF 12 72 25 21 2.5 245 1.05 59 59 nd 2.0 nd -3.3NRF 13 64 19 62 4.2 113 1.65 60 73 nd 0.8 nd 18.8

Radioactive Waste Management Complex

RWMC M3S 43.4 15 8.2 2.6 176 0.95 13.4 24.3 0.30 0.7 23.6 -0.6RWMC M7S 39.6 14 7.8 2.7 172 1.16 11.9 22.2 0.20 0.7 23.5 -2.4RWMC Production 45.0 15 9.0 2.8 180 0.96 13.0 27.0 0.20 0.7 28.0 -0.3
160 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho Table 13. Concentrations of major ions, silica, and the charge balance for each water-quality analysis, Idaho National Laboratory and vicinity, eastern Idaho.—Continued Site name Calcium Magnesium Sodium Potassium Bicarbonate Carbonate Chloride Sulfate Fluoride Nitrate Silica Charge balance (percent) Contaminated groundwater—Continued Radioactive Waste Management Complex—Continued USGS 87 40.0 14 12 3.0 135 0.73 13 26 0.20 0.7 28.0 7.8 USGS 88 33.0 23 47 7.0 113 0.80 82 64 0.30 1.8 30.0 0.8 USGS 90 44.0 15 9.4 2.7 146 0.78 13 27.0 0.20 0.7 27.0 6.8 USGS 120 34.0 18.4 25.4 4.0 186 1.22 21.7 38.0 0.26 0.8 22.4 -1.6 Test Area North Area TAN Disposal 57 22 97 4.3 279 1.34 150 4(32) 0.1 <0.1 23 -2.9 TDD 1 53 20 15 3.5 149 0.61 64 39 0.2 1.2 19 -1.4 TDD 2 71 19 57 4.4 237 0.84 120 40 0.2 2.3 19 -3.8 USGS 24 74.0 19 26 2.4 215 0.90 69 36 0.20 1.7 21.0 0.5 Natural groundwater North INL Area ANP 6 46.2 17.2 9.6 2.5 180 0.77 17.2 32.2 0.26 0.8 20.7 0.0 ANP 8 45.0 14 8.8 3.2 155 0.94 10 30 0.20 0.9 27.0 4.2 IET 1 Disposal 49 13.9 15.9 3.6 189 0.66 18.7 29.9 0.21 1.4 18.8 -0.1 No Name 1 34.0 15.2 10.0 3.5 139 0.68 19.9 24.2 0.29 0.6 25.7 0.7 PSTF Test 30.4 14.9 6.5 2.4 164 1.08 6.6 14.4 0.21 0.6 23.7 -2.8 TDD 3 51 15 7.4 3.1 155 0.38 12 33 0.2 0.9 23 6.7 Northeast INL Area ANP 9 38.1 15.7 13.7 2.9 177 0.96 12.6 29.1 0.39 0.7 30.6 -1.3 USGS 26 41.2 14.9 13.2 3.5 182 0.82 13.3 28.6 0.43 0.8 32.7 -1.4 USGS 27 54.0 19.1 24.0 6.4 170 0.79 61.9 38.5 0.58 2.4 37.2 -0.8 USGS 29 48.5 14.1 19.0 3.4 192 0.81 26.0 16.7 0.43 2.0 28.2 0.8 USGS 31 41.0 15.3 14.4 3.9 172 0.74 22.5 27.7 0.41 0.8 30.9 -1.3 USGS 32 49.5 18.7 17.7 4.2 163 0.59 42.0 39.1 0.38 1.4 28.9 0.8 Southeast INL Area Arbor Test 1 34.9 11.5 14.4 3.1 162 0.69 14.5 12.4 0.64 1.2 34.0 -1.0 Area II 34.2 13.8 14.3 3.4 170 0.92 17.3 16.8 0.44 1.1 28.7 -2.8 Atomic City 34.1 13.4 14.7 3.4 168 1.14 17.2 16.1 0.49 1.1 31.4 -2.5 Leo Rogers 1 39.6 14.3 17.0 3.2 171 0.94 18.8 18.1 0.44 1.1 27.0 1.7 USGS 1 31.2 11.9 13.5 3.2 158 1.08 13.0 13.0 0.57 0.9 32.5 -2.3 USGS 2 35.4 12.1 15.1 3.3 166 0.89 17.0 14.1 0.57 1.2 28.7 -1.9 USGS 14 36.9 15.3 15.5 2.8 168 1.16 21.0 21.5 0.79 1.1 30.4 -1.3 USGS 100 38.3 12.3 16.0 3.1 164 0.88 17.7 21.0 0.57 1.5 28.2 -1.2 USGS 107 37.6 16.6 15.4 3.5 176 0.98 21.3 25.3 0.34 1.0 29.7 -1.7 USGS 110A 36.7 14.9 15.2 3.6 173 0.96 19.0 18.0 0.45 1.1 31.7 -0.9 Central INL Area Badging Facility Well 37.9 14.1 9.7 2.3 162 0.83 16.9 21.4 0.22 0.7 24.4 -1.8 NPR Test 49.1 14.1 7.2 2.1 195 1.01 13.6 20.9 0.22 0.7 22.7 -1.6 USGS 5 39.8 12.6 7.1 2.0 171 0.93 9.4 18.7 0.21 0.5 23.1 -2.2 USGS 6 28.7 11.3 11.7 2.4 146 0.78 9.4 18.1 0.23 0.3 24.9 -2.7
Tables 10–17 161

Table 13. Concentrations of major ions, silica, and the charge balance for each water-quality analysis, Idaho National Laboratory and vicinity, eastern Idaho.—Continued

Site name Calcium Magnesium Sodium Potassium Bicarbonate Carbonate Chloride Sulfate Fluoride Nitrate Silica

Charge 

balance

(percent)

Natural groundwater—Continued

Central INL Area—Continued

USGS 17 37.4 10.1 6.9 2.3 151 1.00 4.9 19.1 0.21 0.3 21.8 -0.4USGS 18 35.1 15.8 12.1 2.9 168 0.76 10.2 24.7 0.30 0.4 25.8 0.3USGS 83 27.3 10.6 9.7 2.5 123 0.77 10.8 20.1 0.24 0.7 25.5 -1.9USGS 103 36.1 15.3 12.6 3.0 167 1.41 16.3 23.1 0.32 0.7 24.3 -1.5

Northwest INL Area

Fire Station 2 54.8 17.8 8.1 2.4 204 0.83 17.6 23.5 0.19 1.2 22.7 1.8INEL-1 WS 67.5 27.4 14.5 2.6 195 0.68 66.6 40.4 0.12 3.6 20.9 0.9NRF 2 70 22 18 1.8 260 0.57 46 39 0.30 1.7 22.0 -3.1NRF 7 24 9.0 10 2.8 129 1.78 5.2 14 nd 0.5 nd -2.2NRF 8 71 24 14 2.2 261 1.10 35 35 nd 1.9 nd 0.1Site 4 45.3 14.1 7.8 1.8 192 0.97 10.1 19.4 0.20 0.6 22.5 -1.5Site 17 51.0 17.3 9.8 1.3 219 0.73 9.9 20.4 0.12 1.0 14.5 0.4Site 19 42.4 17.5 8.0 1.9 200 0.90 11.6 20.7 0.19 0.9 18.8 -2.3USGS 12 71.1 23.3 15.9 2.2 261 0.71 37.6 37.0 0.13 2.3 18.2 -0.7USGS 19 44.1 16.9 10.5 1.5 197 0.61 9.9 20.6 0.21 0.8 14.9 0.7USGS 22 34.7 10.6 21.0 5.6 87 0.34 66.5 21.0 0.17 0.4 17.9 -1.7USGS 23 37.4 15.8 9.2 1.6 182 0.65 9.9 17.6 0.21 0.6 16.1 -1.3USGS 97 73.0 24.3 15.4 2.2 269 0.91 38.0 35.9 0.20 2.2 18.2 -0.4USGS 98 48.9 18.3 10.0 2.3 209 0.87 15.2 21.7 0.12 1.1 20.9 0.2USGS 99 59.8 22.6 12.2 1.7 247 0.83 22.2 27.0 0.15 1.5 16.2 0.3USGS 102 73.9 23.2 13.5 2.2 264 0.90 34.0 35.5 0.13 2.1 18.2 0.3USGS 134 (sz) 24.8 16 7.2 2.2 156 0.52 9.6 20.7 0.21 0.6 27 -6.5

Southwest INL Area

Highway 3 50 12 6.2 2.2 184 1.58 6.3 20 0.2 0.3 26 1.5Middle 2051 (sz) 46.3 11.1 5.7 2.4 188 0.24 5.7 22.0 0.25 0.4 24.3 -3.0USGS 8 46.8 15.0 6.9 1.8 201 0.82 8.4 21.0 0.20 0.9 18.9 -1.9USGS 9 40.7 15.6 12.2 3.5 172 1.09 20.9 26.0 0.20 0.7 23.1 -1.4USGS 11 41.2 14.2 8.2 2.1 173 0.88 11.8 23.1 0.19 0.6 19.2 -1.3USGS 86 37.0 10.2 11.0 2.9 132 1.00 19.6 22.7 0.16 1.4 25.5 -1.4USGS 89 27.2 15.6 17.9 3.7 95 1.63 38.8 34.9 0.33 1.8 24.7 -0.9USGS 117 25.7 11.2 9.6 2.6 121 0.98 13.7 17.1 0.22 0.6 27.7 -2.3USGS 1192 30.0 10.0 11.0 2.6 116 0.98 12.0 35.0 0.50 1.3 31.0 -4.3USGS 125 40.8 15.9 11.8 2.7 178 0.75 14.9 25.8 0.21 0.6 21.6 -0.4USGS 135 (sz) 43.0 11.9 7.0 1.7 166 0.53 7.6 20.3 0.25 0.8 19.0 0.4

1Data from samples collected 04-10-1997 and 05-07-1985.2Data from sample collected in September 1990.3Data from sample collected 10-30-1984.4The sulfur in these anoxic waters should originally have been in a reduced state as bisulfide (HS-). The reported sulfate concentrations in these samples probably reflects oxidation of the sulfur after sampling 

that converted bisulfide to sulfate.
162 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 14. Concentrations of selected dissolved metals, Idaho National Laboratory and vicinity, eastern Idaho.

[Concentrations are in micrograms per liter for dissolved metals, unless specified otherwise. Data from Busenberg and others (2000), Rattray (2015), Knobel 

and others (1992, 1999a, 1999b), U.S. Geological Survey (2014), Swanson and others (2002, 2003), Carkeet and others (2001), Liszewski and Mann, 1993; 

Bartholomay and Twining (2010), Bartholomay and others (2015), Mann (1986), Roback and others, (2001), and Johnson and others (2000). Springs are shown 

in italics. Locations of sites shown on figures 8–9. Site name: Alternate names used in other reports shown in table 10. Abbreviations: sz, shallowest zone; nd, 

not determined; INL, Idaho National Laboratory. Symbols: <, less than; E, estimated (Childress and others, 1999)]

Site name Aluminum Barium Boron Chromium Iron Lithium Manganese Strontium Uranium

Surface water

Big Lost River at Mackay Dam 60 59 12 <1 61 1.7 3.5 146 1.4

Big Lost River at bridge near Mackay 42 57 11 <1 43 1.7 3.1 148 1.4

Big Lost River near Arco 10 110 nd 0 <10 nd 10 260 nd

Big Lost River below INL Diversion 10 69 nd <5 11 <4 2 210 2.20

Big Lost River near Atomic City1 17 105 23 nd 94 2.3 1.3 276 2.26

Big Lost River below lower Lincoln Blvd Br 116 60 13 <1 100 2.0 1.6 164 1.9

Birch Creek at Kaufman Guard Station nd 62 nd <17 <11 nd <4 143 nd

Birch Creek at Blue Dome 1 61 14 <1 28 3.1 0.6 150 2.2

Camas Creek below diversion near CNWR 14 33 8 0.2 31 2.6 2.3 77 nd

Little Lost River near Clyde nd 44 nd nd <20 nd <10 105 nd

Little Lost River near Howe 30 51 12 <1 39 1.1 1.5 91 0.91

Mud Lake near Terreton 42 40 14 <1 58 3.4 2.7 118 0.47

Tributary Valley groundwater

Big Lost River Valley

Arco City Well 4 1 135 11 1 43 1.0 <0.1 257 2.5

Coates <10 39 nd <1 14 <6 <3 153 nd

Fulton 9.4 185 nd E4.7 E4.4 nd E1.1 357 nd

Hill <10 88 nd 1.3 <10 <6 <3 171 nd

Lambert <10 132 nd <1 <10 <6 <3 254 nd

MSR 4 66 nd E2.9 E6.3 nd E0.4 202 nd

Muffett 9 163 nd E2.1 E2.8 nd E0.7 316 nd

Owen 8 167 nd E12 E2.6 nd E0.14 322 nd

Wheeler 8.6 149 nd <1 12 <6 E0.7 323 nd

Wildhorse Guard Station 5 112 nd E15 655 nd 18 686 nd

Little Lost River Valley

Harrell nd 132 nd nd <10 nd 5 217 nd

Mays nd 97 nd 49 <10 6 <2.2 323 nd

Nicholson nd 58 nd nd 13.2 nd E1.7 363 nd

Oar nd 60 nd nd <20 nd <10 126 nd

Pancheri 1 71 16 2 29 1.5 <0.1 135 1.2

Ruby Farms <10 110 nd 8 14 5 <1 240 nd

Sorenson nd 38 nd nd <10 nd <2.2 92 nd

Birch Creek Valley

Kaufman Guard Station nd 164 nd 1 67 12 39 347 nd

McKinney nd 64 nd <1 7 5 <1 170 nd

P&W2 5 45 17 1 38 2.9 0.3 137 1.86

USGS 126b E10 46 nd 2 <10 5.5 <3.2 201 nd

Wagoner <1 69 18 <1 48 3.3 2.7 163 1.9

Wagoner Ranch nd 78 nd <17 <11 nd <4 177 nd

Beaverhead Mountains

ML 55 <2.2 87 25 0.2 13.8 9.6 <0.1 146 nd

ML 59 <2.2 143 8 0.5 <3.2 0.9 <0.1 61 nd
Tables 10–17 163

Table 14. Concentrations of selected dissolved metals, Idaho National Laboratory and vicinity, eastern Idaho.—Continued

Site name Aluminum Barium Boron Chromium Iron Lithium Manganese Strontium Uranium

Regional groundwater

Highway 22 <10 nd 70 nd 80 nd 100 nd nd

Kettle Butte Farms nd nd nd <1 5 nd <1.0 nd nd

ML 2 nd 10 nd nd <6 nd E0.2 nd nd

ML 5 3 26 25 2.5 <3.2 7.2 1.6 131 nd

ML 6 10 21 19 1.2 5.0 12.4 <0.1 100 nd

ML 9 nd nd nd nd <3.2 nd <0.2 nd nd

ML 12 <1.7 30 21 1.5 3.6 12.9 <0.1 127 nd

ML 13 nd nd nd nd E5.7 nd <0.4 nd nd

ML 15 nd 29 nd nd <6 nd E0.1 nd nd

ML 18 nd nd nd nd E3.4 nd 1.5 nd nd

ML 17 <2.2 56 117 0.3 3.3 6.3 0.2 400 nd

ML 19 2 151 36 nd 73 14.4 nd 331 3.2

ML 22 3 130 48 11 78 23.7 <0.1 312 3.59

ML 23 nd 95 50 nd 5.0 32 nd 180 nd

ML 24 <2.2 127 90 2.6 5.2 16 0.2 502 nd

ML 25 3 62 84 nd 85 71 91 77 0.1

ML 26 nd 112 nd nd <6 nd <0.6 nd nd

ML 27 nd 51 nd nd E4.8 47 5.7 150 nd

ML 28 nd 74 nd nd <6 nd <0.6 nd nd

ML 29 10 51 nd nd 11 47 nd 160 nd

ML 30 <2.2 138 78 7.4 5.4 27.8 0.3 329 nd

ML 31 <2.2 78 82 2.3 4.7 20 <0.1 308 nd

ML 33 nd 81 nd nd <10 nd <2.0 nd nd

ML 34 nd 56 nd nd <10 nd <3.0 nd nd

Reno Ranch nd 114 nd 1 <10 25 9 322 nd

SE of Atomic City nd nd nd 1.5 <3 nd <1.0 nd nd

USGS 3A nd nd 80 nd 120 nd 0 nd nd

USGS 101 6 18 47 2 39 27.8 0.2 111 1.32

Geothermal water

INEL-1 2,000 feet nd nd 900 20 0 50 20 100 1.88

INEL-1 10,300 feet3 nd nd 560 0 1,100 280 50 150 0.19

ML 57 E14 45 90 <0.8 20 48.1 13 1,000 0.02

ML 58 <2.2 70 35 0.2 <3.2 15.1 0.2 337 nd

Groundwater at the Idaho National Laboratory

Deep groundwater

EBR 1 10 21 20 7 34 2.7 0.4 195 2.03

Site 9 9 60 30 4 51 3.5 3.8 188 1.68

Site 14 6 63 35 5 37 11.5 <0.1 215 2.07

USGS 7 5 17 57 2 35 25.9 3.6 120 2.26

USGS 15 3 65 18 7 30 2.1 <0.1 188 1.78

Contaminated groundwater

Advanced Test Reactor Complex

USGS 65 <10 56 nd 190 210 5 3 390 nd

Idaho Nuclear Technology and Engineering Center

CFA1 4 91 21 10 68 2.5 0.2 370 2.3

CFA2 4 96 27 10 158 3.6 2.8 483 2.3

USGS 20 <10 47 nd 7 21 6 2 230 nd

USGS 36 3 126 21 13 57 1.7 <0.1 334 2.5

USGS 57 10 170 nd <5 4 <4 <1 360 nd

USGS 82 3 57 19 6 62 2.2 1.3 214 1.7

USGS 85 <10 110 nd 10 28 6 3 310 nd

USGS 104 3 32 16 7 62 2.2 0.3 184 1.52
164 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 14. Concentrations of selected dissolved metals, Idaho National Laboratory and vicinity, eastern Idaho.—Continued

Site name Aluminum Barium Boron Chromium Iron Lithium Manganese Strontium Uranium

Contaminated groundwater—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 105 5 38 22 7 45 2.5 0.1 235 2.16

USGS 108 4 38 23 7 41 4.3 0.1 189 1.76

USGS 109 4 26 23 5 46 2.7 5.8 307 1.73

USGS 112 5 250 24 6 89 2.4 0.1 484 2.3

USGS 113 2 342 26 6 122 2.8 0.1 532 2.1

USGS 115 5 65 18 7 54 2.1 1.5 244 1.3

USGS 116 3 136 18 12 84 2.5 0.3 333 1.4

USGS 124 5 26 21 4 89 6.7 9.4 256 1.61

Naval Reactors Facility

NRF 64 <10 <100 nd 27 240 nd <10 nd nd

NRF 94 <10 <100 nd 12 30 nd <10 nd nd

NRF 104,5 1,000 <100 nd 14 1,700 nd 40 nd nd

NRF 114 40 <100 nd 23 60 nd <10 nd nd

NRF 124 10 <100 nd 17 <10 nd <10 nd nd

NRF 134,5 1,400 <100 nd 26 1,300 nd <10 nd nd

Radioactive Waste Management Complex

RWMC M3S 7 45 18 15 51 2.4 0.1 244 2.1

RWMC M7S 6 46 17 11 53 2.2 0.1 231 2.0

RWMC Production 20 37 nd 20 7 nd 130 240 nd

USGS 87 <10 29 nd 10 6 nd 3 230 nd

USGS 88 <10 22 nd 30 7 9 6 190 nd

USGS 90 <10 35 nd 20 4 nd 2 240 nd

USGS 120 5 48 39 9 70 3.6 1 197 2.8

Test Area North

TAN Disposal <10 130 nd <1 410 nd 84 350 nd

TDD 1 <10 68 nd 2 30 nd 3 270 nd

TDD 2 10 240 nd <1 8 nd 17 470 nd

USGS 24 <10 190 nd 4 15 nd 2 450 nd

Natural groundwater

North INL Area

ANP 6 6 65 26 3 61 2.9 1.1 218 2.12

ANP 8 20 86 nd 5 5 nd <1 210 nd

IET 1 Disposal 3 120 72 <1 86 2.3 140 251 1.8

No Name 1 20 63 20 8 80 2.5 2.1 181 1.5

PSTF Test 4 70 19 3 28 1.8 <0.1 132 1.7

TDD 3 20 84 nd 3 5 nd 1 230 nd

Northeast INL Area

ANP 9 5 86 35 3 27 10.2 0.9 208 2.37

USGS 26 4 37 38 3 56 18.4 0.6 196 2.39

USGS 27 2 69 52 5 101 36.4 5.7 256 3.04

USGS 29 4 52 36 4 55 23.7 <0.1 158 2.00

USGS 31 4 43 37 5 48 18.1 0.2 196 2.27

USGS 32 2 58 43 5 67 19.1 0.4 246 2.53

Southeast INL Area

Arbor Test 1 5 29 46 2 36 24.9 0.3 125 1.69

Area II 7 36 41 3 56 17.7 <0.1 152 1.94

Atomic City 7 38 40 3 28 18 0.1 164 2.1

Leo Rogers 1 6 43 40 3 58 16 <0.1 145 2.2

USGS 1 6 23 42 2 51 18 0.8 133 1.72

USGS 2 5 34 45 2 87 20.4 3.7 131 1.82
Tables 10–17 165

Table 14. Concentrations of selected dissolved metals, Idaho National Laboratory and vicinity, eastern Idaho.—Continued

Site name Aluminum Barium Boron Chromium Iron Lithium Manganese Strontium Uranium

Natural groundwater—Continued

Southeast INL Area—Continued

USGS 14 6 20 36 4 37 24.3 0.6 178 2.37

USGS 100 2 32 44 3 39 23.4 0.5 133 1.50

USGS 107 4 49 35 5 34 10.5 <0.1 120 2.20

USGS 110A 6 32 38 3 125 15.9 7.2 205 2.03

Central INL Area

Badging Facility Well 5 35 21 9 57 3.9 0.2 197 1.50

NPR Test 3 84 20 7 45 2.2 1.2 244 2.0

USGS 5 6 89 19 2 39 2 47.4 189 1.50

USGS 6 4 78 25 28 53 7.3 0.9 182 1.75

USGS 17 9 35 13 2 40 1.4 0.7 208 1.71

USGS 18 7 55 33 3 47 5.2 0.5 165 2.06

USGS 83 5 95 15 14 26 3 0.3 157 1.37

USGS 103 6 45 30 6 49 6.9 2.2 186 1.49

Northwest INL Area

Fire Station 2 7 20 24 7 56 2 0.5 303 2.0

INEL-1 WS 1 62 19 8 105 2.8 3.6 309 1.69

NRF 2 30 140 nd 9 6 nd <1 300 nd

NRF 74 70 <100 nd 13 230 nd <10 nd nd

NRF 84 <10 <100 nd 7 80 nd <10 nd nd

Site 4 7 nd 20 8 30 1.7 <0.1 231 1.9

Site 17 18 74 26 4 59 2.4 0.2 206 1.43

Site 19 5 49 25 3 55 2.5 <0.1 211 1.7

USGS 12 3 179 33 7 85 2.7 1.1 357 2.4

USGS 19 5 80 32 3 46 3.5 0.3 256 1.56

USGS 22 4 17 33 2 54 3.7 15.1 114 0.43

USGS 23 5 55 26 3 54 4.3 0.9 219 1.9

USGS 97 2 143 29 6 68 2.6 <0.1 316 2.4

USGS 98 2 43 22 6 50 2.5 6 222 1.5

USGS 99 3 112 30 5 58 2.5 0.9 252 1.8

USGS 102 4 124 30 7 70 2.9 <0.1 308 2.5

USGS 134 (sz) 3 11 nd 6 <8 2.0 0.6 145 nd

Southwest INL Area

Highway 36 27 54 21 nd 97 1.7 0.9 276 1.90

Middle 2051 (sz) 2 45 nd 1 <8 1.6 E0.2 255 1.69

USGS 8 6 70 13 2 45 1.3 1.1 254 2.10

USGS 9 4 34 25 4 40 3.3 3.9 202 1.57

USGS 11 6 52 16 4 42 2.1 0.6 220 1.67

USGS 86 2 19 18 12 37 2.3 0.8 171 1.03

USGS 89 3 18 30 45 63 4.2 0.4 118 1.16

USGS 117 3 18 23 21 49 5.1 0.8 144 1.1

USGS 119 <10 28 nd 30 6 5 4 130 nd

USGS 125 6 35 21 5 56 3.2 5.5 230 2.17

USGS 135 (sz) 8 56 nd 2 6 1.9 0.4 245 nd

1

Data are from samples collected on 04-10-1997 and 05-07-1985.

2

Aluminum value from sample collected in 1984.

3

Lithium measurement from sample collected at 3,559–4,878 feet below land surface.

4

Total recoverable metals.

5

Extremely large total recoverable aluminum and iron concentrations may be due to suspended sediment (U.S. Department of Energy, 2016).

6

 Data from sample collected 04-29-1997 (Johnson and others, 2000; Roback and others, 2001).
166 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 15. Stable isotope ratios of hydrogen, oxygen, carbon, sulfur, and nitrogen, and the isotope ratio of helium, Idaho National 

Laboratory and vicinity, eastern Idaho.

[Locations of sites shown in figures 8–9. Alternate names used in other reports are shown in table 10. Data from Busenberg and others (2000); Rattray (2015); 

Knobel and others (1992, 1999a, 1999b); U.S. Geological Survey (2014); Swanson and others (2002, 2003); Carkeet and others (2001); Bartholomay and 

Twining (2010); Bartholomay and others (1994, 1995, 2015); and Wood and Low (1988). Date sampled: Date that hydrogen, oxygen, and most carbon isotope 

samples were collected. Helium isotopes were collected in 1994–95, and most sulfur and nitrogen stable isotope samples were collected in 1991. δ2H and δ18O:

Measured from water. δ13C: Measured from dissolved inorganic carbon. δ34S: Measured from sulfate. δ15N: Measured from nitrate. Springs are shown in italics. 

Abbreviations: INL, Idaho National Laboratory; sz, shallowest zone. Symbols: δ2H, δ18O, δ13C, δ34S, δ15N, and δ3He, delta notation for the stable isotope ratios 

of hydrogen, oxygen, carbon, sulfur, nitrogen and isotope ratio of helium, respectively; Rs, (3He/4He)sample; Ra, (3He/4He)atmosphere; ≈, approximately; ±, plus or 

minus the indicated uncertainty (uncertainties are 1 sigma); nd, not determined]

Site 

name

Date

sampled

δ2H

(±1.0 permil)

δ18O

(±0.10 permil)

δ13C

(±0.1 permil)

δ34S

(±0.1 permil)

δ15N

(±0.1 permil)

δ3He

(±≈0.2 

percent)

Rs/Ra

Surface water

Big Lost River at Mackay Dam 06-28-1995 -134.4 -17.57 nd nd nd nd nd

Big Lost River at Bridge near 

Mackay

06-17-1995 -134.9 -17.60 nd nd nd nd nd

Big Lost River near Arco 06-05-1981 -135.0 -17.4 -10.9 4.4 nd nd nd

Big Lost River below lower Lincoln 

Blvd Br

05-21-1997 -132.2 -17.17 -10.9 nd nd nd nd

Birch Creek at Kaufman Guard 

Station

06-27-2000 -141.2 -18.57 -5.92 nd nd nd nd

Birch Creek at Blue Dome 06-28-1995 -140.1 -18.62 nd 18.2 nd nd nd

Camas Creek below diversion near 

CNWR

08-08-2011 -124.7 -16.24 -7.98 26.9 nd nd nd

Little Lost River near Clyde 06-27-2000 -137.4 -17.94 -6.57 nd nd nd nd

Little Lost River near Howe 06-28-1995 -134.1 -17.72 -6.9 nd nd nd nd

Mud Lake near Terreton 06-17-1995 -122.9 -15.97 nd nd nd nd nd

Tributary valley groundwater

Big Lost River Valley

Arco City Well 4 05-13-1997 -134.7 -17.69 -10.33 1.6 nd nd nd

Coates 06-01-1999 -134.7 -17.60 -7.9 nd nd nd nd

Fulton 06-02-1999 -130.7 -17.28 -10.79 nd nd nd nd

Hill 06-02-1999 -134.0 -17.72 -9.03 nd nd nd nd

Lambert 06-23-1999 -135.1 -17.60 -10.88 nd nd nd nd

MSR 06-01-1999 -136.7 -18.12 -9.01 nd nd nd nd

Muffett 06-03-1999 -131.9 -17.19 -12 nd nd nd nd

Owen 06-23-1999 -132.0 -17.32 -11.84 nd nd nd nd

Wheeler 06-02-1999 -132.6 -17.32 -11.47 nd nd nd nd

Wildhorse Guard Station 06-02-1999 -141.7 -18.37 -7.88 nd nd nd nd

Little Lost River Valley

Harrell 07-31-2000 -135.2 -17.93 -9.27 1.8 nd nd nd

Mays 06-26-2000 -141.2 -18.35 -7.1 nd nd nd nd

Nicholson 07-31-2000 -133.7 -17.59 -6.17 nd nd nd nd

Oar 06-28-2000 -138.7 -18.11 -10.21 nd nd nd nd

Pancheri 05-13-1997 -141.8 -18.14 -8.42 nd nd nd nd

Ruby Farms 05-10-1991 -138.0 -18.15 -9.1 3.3 6.0 nd nd

Sorenson 07-31-2000 -137.9 -18.06 -9.12 nd nd nd nd

Birch Creek Valley

Kaufman Guard Station 06-27-2000 -139.7 -18.39 -11.14 nd nd nd nd

McKinney 06-13-1991 -141.0 -18.55 -7.9 7.6 6.7 nd nd

P&W2 10-15-1996 -141.3 -18.50 -6.13 7.7 7.0 -0.84 0.99

USGS 126b 11-08-2000 -140.9 -18.44 -6.41 nd nd nd nd

Wagoner 05-22-1997 -141.7 -18.13 -8.97 nd nd nd nd

Wagoner Ranch 06-28-2000 -139.2 -18.35 -7.37 nd nd nd nd
Tables 10–17 167

Table 15. Stable isotope ratios of hydrogen, oxygen, carbon, sulfur, and nitrogen, and the isotope ratio of helium, Idaho National 

Laboratory and vicinity, eastern Idaho.—Continued

Site 

name

Date

sampled

δ2H

(±1.0 permil)

δ18O

(±0.10 permil)

δ13C

(±0.1 permil)

δ34S

(±0.1 permil)

δ15N

(±0.1 permil)

δ3He

(±≈0.2 

percent)

Rs/Ra

Beaverhead Mountains

ML 55 06-5-2012 -137.7 -18.03 -9.47 nd nd nd nd

ML 59 06-5-2012 -129.2 -17.02 -9.12 nd nd nd nd

Regional groundwater

ML 5 08-09-2011 -131.5 -17.33 -11.2 nd nd nd nd

ML 6 08-08-2011 -132.9 -17.62 -13.4 nd nd nd nd

ML 9 08-29-1989 -133.0 -17.45 nd nd nd nd nd

ML 12 08-09-2011 -134.4 -17.62 -13.2 nd nd nd nd

ML 17 06-04-2012 -134.1 -17.35 -11.4 nd nd nd nd

ML 19 05-14-1997 -120.8 -14.88 -12.7 nd nd nd nd

ML 22 10-15-1996 -120.6 -14.84 -13.32±0.04 8.2 4.7 13.47 1.13

ML 23 08-29-1989 -123.0 -15.55 nd nd nd nd nd

ML 24 06-06-2012 -132.3 -17.26 -13.10 nd nd nd nd

ML 25 06-11-1991 -135.0 -17.9 -12.6 8.3 6.9 nd nd

ML 29 06-12-1991 -135.0 -17.85 -11.7 16.0 9.5 nd nd

ML 30 06-06-2012 -130.9 -16.98 -15.0 nd nd nd nd

ML 31 06-06-2012 -132.4 -17.13 -12.30 nd nd nd nd

Reno Ranch 06-28-2000 -139 -18.2 -7.09 5.1 nd nd nd

USGS 101 10-10-1996 -135.3 -17.84 -10.60 11.8 5.1 -33.16 0.67

Geothermal water

ML 57 11-05-1990 -135.0 -18.10 -3.9 8.4 nd nd nd

ML 58 06-05-2012 -135.0 -17.65 -5.55 nd nd nd nd

Groundwater at the Idaho National Laboratory

Deep groundwater

EBR 1 10-16-1996 -139.4 -18.13 -8.0 6.9 6.3 nd nd

Site 9 07-22-1996 -137.7 -17.98 -8.51±0.02 8.6 6.2 nd nd

Site 14 10-14-1996 -137.8 -17.96 -8.17 9.2 5.8 nd nd

USGS 7 10-14-1996 -137.6 -17.93 -9.48 11.9 6.0 nd nd

USGS 15 06-14-1995 -141.8 -18.49 -8.01 nd nd nd nd

Contaminated groundwater

Advanced Test Reactor Complex

USGS 65 05-16-1991 -133.0 -16.90 -10.4 4.8 6.6 nd nd

Idaho Nuclear Technology and Engineering Center

CFA 1 07-16-1996 -137.4 -17.71 -9.43 6.9 8.1 nd nd

CFA 2 07-16-1996 -136.6 -17.23 -11.99±0.05 nd nd nd nd

USGS 20 05-30-1991 -139.0 -18.10 -10.8 6.0 5.1 nd nd

USGS 36 07-16-1996 -137.6 -17.78 -8.78 nd nd nd nd

USGS 57 05-13-1991 -136.0 -17.70 -11.3 5.3 5.9 nd nd

USGS 82 07-16-1996 -137.5 -17.89 -10.02 nd nd nd nd

USGS 85 06-04-1991 -136.0 -17.90 -11.0 5.8 5.4 nd nd

USGS 104 07-15-1996 -139.1 -18.09 -9.30±0.03 nd nd nd nd

USGS 105 04-18-1995 -136.7 -17.84 nd nd nd -31.11 0.69

USGS 108 04-18-1995 -137.2 -17.85 nd nd nd nd nd

USGS 109 10-11-1996 -137.0 -17.78 -9.08 nd nd 207.28 3.07

USGS 112 07-15-1996 -137.8 -17.62 -9.92 4.7 6.0 nd nd

USGS 113 07-16-1996 -137.1 -17.51 -10.67 nd nd nd nd

USGS 115 07-15-1996 -140.1 -17.87 -10.27±0.02 nd nd nd nd

USGS 116 07-15-1996 -138.9 -17.74 -10.56±0.00 nd nd nd nd

USGS 124 10-09-1996 -138.8 -17.95 -8.75 nd nd 646.05 7.46
168 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 15. Stable isotope ratios of hydrogen, oxygen, carbon, sulfur, and nitrogen, and the isotope ratio of helium, Idaho National 

Laboratory and vicinity, eastern Idaho.—Continued

Site 

name

Date

sampled

δ2H

(±1.0 permil)

δ18O

(±0.10 permil)

δ13C

(±0.1 permil)

δ34S

(±0.1 permil)

δ15N

(±0.1 permil)

δ3He

(±≈0.2 

percent)

Rs/Ra

Radioactive Waste Management Complex

RWMC M3S 07-22-1996 -137.5 -17.98 -8.87 nd nd nd nd

RWMC M7S 07-22-1996 -137.7 -17.92 -9.22 nd nd nd nd

USGS 120 07-17-1996 -136.8 -17.61 -9.38 nd nd nd nd

Natural groundwater

North INL Area

ANP 6 07-19-1996 -138.7 -18.27 -6.06 nd nd 15.75 1.16

IET 1 Disposal 07-18-1996 -135.7 -17.58 -8.80±0.01 nd nd nd nd

No Name 1 10-14-1996 -130.4 -15.86 -8.76 6.9 7.1 -1.13 0.99

PSTF Test 10-14-1996 -133.4 -17.64 -5.61 nd nd -0.28 1.00

Northeast INL Area

ANP 9 10-14-1996 -137.9 -17.88 -8.21±0.07 nd nd -99.95 0.001

USGS 26 10-15-1996 -134.6 -17.80 -8.61 10.5 6.3 nd nd

USGS 27 10-15-1996 -134.0 -17.66 -9.87 10.7 7.6 869.50 9.70

USGS 29 07-19-1996 -134.5 -17.67 -11.75 10.2 5.3 -41.64 0.58

USGS 31 07-19-1996 -135.9 -17.81 -9.39 11.0 6.5 nd nd

USGS 32 07-19-1996 -135.4 -17.68 -9.47 9.0 6.5 27.18 1.27

Southeast INL Area

Arbor Test 1 10-10-1996 -133.6 -17.74 -11.21±0.01 nd nd 3.36 1.03

Area II 07-18-1996 -134.8 -17.73 -10.23±0.01 nd nd -99.75 0.003

Atomic City 10-09-1996 -135.8 -17.72 -10.57±0.01 nd nd 17.07 1.17

Leo Rogers 1 07-17-1996 -134.7 -17.62 -10.59±0.02 nd nd nd nd

USGS 1 10-09-1996 -136.2 -17.82 -10.71±0.00 11.9 4.7 21.21 1.21

USGS 2 07-17-1996 -135.0 -17.71 -11.67±0.02 11.0 4.7 11.12 1.11

USGS 14 10-09-1996 -135.5 -17.61 -9.29±0.00 9.5 6.5 25.39 1.25

USGS 100 04-21-1995 -133.8 -17.78 -11.17 nd nd 12.27 1.12

USGS 107 10-09-1996 -134.3 -17.55 -9.21±0.05 nd nd nd nd

USGS 110A 10-09-1996 -134.4 -17.64 -10.64±0.01 9.8 5.4 nd nd

Central INL Area

Badging Facility Well 07-16-1996 -139.2 -17.90 -9.39 nd nd nd nd

NPR Test 10-10-1996 -137.6 -17.76 -9.90 5.6 7.1 56.96 1.57

USGS 5 10-10-1996 -138.3 -17.82 -9.64 nd nd 4.17 1.04

USGS 6 07-18-1996 -135.2 -17.62 -8.64 nd nd nd nd

USGS 17 06-13-1995 -135.7 -17.53 -10.09 5.7 8.3 25.75 1.26

USGS 18 07-19-1996 -138.6 -18.11 -7.37 nd nd nd nd

USGS 83 04-17-1995 -138.9 -18.14 nd nd nd nd nd

USGS 103 07-15-1996 -136.9 -17.80 -8.93 nd nd 26.48 1.26

Northwest INL Area

Fire Station 2 10-16-1996 -138.7 -17.94 -9.32 7.9 6.5 nd nd

INEL-1 WS 06-12-1995 -138.6 -17.97 -8.88 nd nd nd nd

Site 4 10-16-1996 -137.9 -17.74 -10.19 nd nd nd nd

Site 17 06-16-1995 -138.9 -18.10 -8.48 7.5 6.3 nd nd

Site 19 07-16-1996 -139.0 -18.04 -8.35 7.2 7.3 nd nd

USGS 12 06-14-1995 -135.0 -17.47 -10.18 nd nd 13.57 1.14

USGS 19 10-15-1996 -138.1 -18.07 -7.06±0.03 8.6 7.2 -23.99 0.76

USGS 22 07-18-1996 -136.8 -17.62 -13.55 nd nd 106.80 2.07

USGS 23 10-15-1996 -138.1 -17.94 -5.72 6.1 5.9 1.62 1.02

USGS 97 06-13-1995 -137.1 -17.55 -10.09 nd nd 28.20 1.28

USGS 98 06-12-1995 -137.6 -18.07 -8.84 nd nd 6.33 1.06
Tables 10–17 169

Table 15. Stable isotope ratios of hydrogen, oxygen, carbon, sulfur, and nitrogen, and the isotope ratio of helium, Idaho National 

Laboratory and vicinity, eastern Idaho.—Continued

Site 

name

Date

sampled

δ2H

(±1.0 permil)

δ18O

(±0.10 permil)

δ13C

(±0.1 permil)

δ34S

(±0.1 permil)

δ15N

(±0.1 permil)

δ3He

(±≈0.2 

percent)

Rs/Ra

Natural groundwater—Continued

Northwest INL Area—Continued

USGS 99 06-12-1995 -136.8 -17.99 -9.68 nd nd 0.75 1.01

USGS 102 06-13-1995 -135.3 -17.50 -9.81 nd nd 28.96 1.29

USGS 134 (sz) 09-04-2008 -137.0 -18.08 -8.48 nd nd nd nd

Southwest INL Area

Middle 2051 (sz) 08-25-2008 -134.1 -17.3 -10.7 nd nd nd nd

USGS 8 10-08-1996 -135.7 -17.78 -9.41±0.00 5.2 5.4 25.65 1.26

USGS 9 10-11-1996 -136.2 -17.75 -9.51 5.8 6.3 81.74 1.82

USGS 11 10-09-1996 -138.6 -17.92 -9.17±0.03 5.6 5.6 43.10 1.43

USGS 86 10-11-1996 -139.4 -18.13 -8.90±0.01 5.7 8.1 0.14 1.00

USGS 89 07-17-1996 -140.4 -18.34 -12.78 nd nd nd nd

USGS 117 07-17-1996 -139.3 -18.05 -10.56 nd nd nd nd

USGS 125 10-11-1996 -136.3 -17.82 -9.38 nd nd nd nd

USGS 135 (sz) 09-14-2010 -137.0 -17.92 -9.06 nd nd nd nd

1

Sulfur isotope data for Birch Creek at 8-mi Canyon Rd near Reno (Wood and Low, 1988).

2

Sulfur isotope data for Camas Creek at shearing corral near Kilgore (Wood and Low, 1988).
170 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 16. Stable isotope ratios of strontium and radioisotope ratios of uranium, Idaho National Laboratory and 

vicinity, eastern Idaho.

[Data from Johnson and others (2000); Roback and others (2001); and McLing and others (2002). 234U/238U (activity ratio): Multiple 

samples (small and large volume) were collected at some sites. Results reported are from a small volume sample where more than 

one sample result was available. Analytical results from sites with two or more results varied by less than or equal to 0.02 (activity 

ratio, rounded two decimal places). Site name: Alternate names used in other reports shown in table 10. Springs are shown in italics. 

Location of sites shown in figures 8–9. Abbreviations: INL, Idaho National Laboratory. ≈, approximately; nd, not determined; ≤, less 

than or equal to; ±, plus or minus the analytical precision; 1997?, uncertain sample collection date]

Site name Date

sampled

87Sr/86Sr

(±0.002 percent)

234U/238U activity ratio

(≈ ±0.25 percent)

Surface water

Big Lost River below INL diversion 07-14-99 nd 2.12

Big Lost River near Atomic City 04-10-97 0.71056 2.25

Little Lost River 1997? 0.71256 nd

Birch Creek 1997? 0.71198 nd

Tributary Valley groundwater

Birch Creek Valley

P&W2 10-15-96 0.71159 3.05

Regional groundwater

ML 22 04-28-97 0.70992 1.71

USGS 101 10-10-96 0.70962 2.28

Geothermal water

INEL-1 2,000 feet 03-24-79 0.70935 3.14

INEL-1 10,300 feet 07-20-79 0.70980 2.07

ML 57 1997? 0.71082 nd

ML 58 1997? 0.71434 nd

Groundwater at the Idaho National Laboratory

Deep groundwater

EBR 1 10-16-96 0.71006 2.07

Site 9 07-22-96 0.71059 2.50

Site 14 08-20-96 0.71085 2.83

USGS 7 04-21-97 nd 2.89

USGS 15 07-25-96 0.71129 2.77

Contaminated groundwater

Idaho Nuclear Technology and Engineering Center

USGS 104 07-15-96 0.71023 2.16

USGS 105 05-05-97 0.71043 2.23

USGS 108 09-09-97 0.71043 2.32

USGS 109 09-01-98 0.71220 2.31

USGS 124 04-10-97 0.71039 2.55

Natural groundwater

North INL Area

ANP 6 07-19-96 0.71073 3.01

No Name 1 10-14-96 0.71037 nd

Northeast INL Area

ANP 9 04-28-97 0.71143 2.99

USGS 26 10-15-96 0.71107 2.82

USGS 27 10-15-96 0.70993 2.35

USGS 29 07-19-96 0.70957 2.13

USGS 31 09-02-98 0.71040 2.61

USGS 32 07-19-96 0.71026 2.45
Tables 10–17 171

Table 16. Stable isotope ratios of strontium and radioisotope ratios of uranium, Idaho National Laboratory and 

vicinity, eastern Idaho.—Continued

Site name Date

sampled

87Sr/86Sr

(±0.002 percent)

234U/238U activity ratio

(≈ ±0.25 percent)

Natural groundwater—Continued

Southeast INL Area

Arbor Test 1 10-10-96 0.70998 2.33

Area II 07-18-96 0.71048 2.48

Atomic City 10-09-96 0.71042 nd

USGS 1 04-21-97 0.71031 2.45

USGS 2 08-26-98 0.71008 2.35

USGS 14 04-10-97 0.71057 2.64

USGS 100 04-28-97 0.71008 2.32

USGS 107 08-27-98 0.71072 2.56

USGS 110A 08-25-98 0.71057 2.49

Central INL Area

Badging Facility well 07-17-96 0.71091 2.53

USGS 5 10-10-96 0.71057 2.05

USGS 6 07-16-96 0.71021 2.27

USGS 17 10-16-96 0.71038 1.96

USGS 18 07-19-96 0.71115 2.91

USGS 83 08-28-98 0.71012 2.07

USGS 103 07-15-96 0.71053 2.41

Northwest INL Area

Site 17 07-25-96 0.71091 3.01

USGS 12 09-10-97 0.71061 2.24

USGS 19 10-15-96 0.71014 3.01

USGS 22 07-18-96 0.70951 1.54

Southwest INL Area

Highway 3 04-29-97 0.71040 2.07

USGS 8 10-08-96 0.70998 2.49

USGS 9 09-01-98 0.71029 2.22

USGS 11 10-09-96 0.71008 2.47

USGS 86 10-11-96 0.70968 2.23

USGS 89 07-17-96 0.70981 1.92

USGS 125 10-11-96 0.71047 2.27
172 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 17. Activity of tritium and approximate age of water samples, calculated percentage of terrigenic helium, apparent age of young 

fraction of groundwater estimated from environmental tracer data, and activity of carbon-14, Idaho National Laboratory and vicinity, 

eastern Idaho.

[Data from Busenberg and others (2000, 2001); Rattray (2015); Knobel and others (1992, 1999a, 1999b); U.S. Geological Survey (2014); Swanson and others 

(2002, 2003); Carkeet and others (2001); Schramke and others (1996); Bartholomay and Twining (2010); and Bartholomay and others (2015). Locations of sites 

shown in figures 8–9. Site name: Alternate names used in other reports shown in table 10. Date sampled: Date that the tritium samples were collected. Springs 

are shown in italics. Abbreviations: INL, Idaho National Laboratory; sz, shallowest zone. Units: pCi/L, picocuries per liter; pmC, percent modern carbon. 

Symbols: ±, plus or minus the indicated standard deviation (standard deviations are 1 sigma); >, greater than; >>, much greater than; nd, not determined; ?, 

uncertain; O, old water; Y, young water; M, mixture of old and young water; C, contaminated water]

Site name Date sampled Tritium

(pCi/L)

Approximate age 

of water sample 

based on tritium 

activity

Terrigenic 

helium 

(percent)

Apparent age of young 

groundwater estimated 

from atmospheric 

tracer data (years 

before sampling date)

Carbon-14 

(pmC)

Surface water

Big Lost River below INL 

Diversion

06-02-1995 52±1.6 Y nd nd 1120

Birch Creek at Kaufman Guard 

Station

06-27-2000 22.4±12.8 Y or M nd nd nd

Camas Creek below diversion near 

CNWR

08-08-2011 26.6±2.1 Y nd nd nd

Little Lost River near Clyde 06-27-2000 38.4±12.8 Y nd nd nd

Little Lost River near Howe 11-08-2000 38.4±12.8 Y nd nd nd

Tributary Valley groundwater

Big Lost River Valley

Arco City Well 4 05-13-1997 83.8±2.9 Y 29 nd nd

Coates 06-01-1999 19.2±12.8 M nd nd nd

Fulton 06-02-1999 54.4±13.4 Y nd nd nd

Hill 06-02-1999 25.6±12.8 Y or M nd nd nd

Lambert 06-23-1999 3.2±12.8 O or M nd nd nd

MSR 06-01-1999 83.2±12.8 Y nd nd nd

Muffett 06-03-1999 57.6±12.8 Y nd nd nd

Owen 06-23-1999 0±12.8 O or M nd nd nd

Wheeler 06-02-1999 19.2±12.8 M nd nd nd

Wildhorse Guard Station 06-02-1999 32±12.8 Y or M nd nd nd

Little Lost River Valley

Harrell 07-31-2000 35.2±12.8 Y or M nd nd nd

Mays 06-26-2000 0±12.8 O or M nd nd nd

Nicholson 07-31-2000 44.8±12.8 Y nd nd nd

Oar 06-28-2000 51.2±12.8 Y nd nd nd

Pancheri 05-13-1997 52.2±1.9 Y 56 nd nd

Ruby Farms 05-10-1991 9.6±13 M or O nd 20 65.4

Sorenson 07-31-2000 51.2±12.8 Y nd nd nd

Birch Creek Valley

Kaufman Guard Station 06-27-2000 32±12.8 Y or M nd nd nd

McKinney 06-13-1991 -3.2±13 O or M nd 2–5 nd

P&W2 10-25-1994 8.1±0.2 M 5 4–16 50.84±0.41

USGS 126b 11-08-2000 6.4±9.6 O or M nd nd nd

Wagoner 05-22-1997 14.7±1.0 M nd nd nd

Wagoner Ranch 06-28-2000 38.4±12.8 Y or M 30 nd nd

Beaverhead Mountains

ML 55 06-05-2012 10.5±2.2 M nd nd nd

ML 59 06-05-2012 33.1±2.5 Y nd nd nd
Tables 10–17 173

Table 17. Activity of tritium and approximate age of water samples, calculated percentage of terrigenic helium, apparent age of young 

fraction of groundwater estimated from environmental tracer data, and activity of carbon-14, Idaho National Laboratory and vicinity, 

eastern Idaho.—Continued

Site name Date sampled Tritium

(pCi/L)

Approximate age 

of water sample 

based on tritium 

activity

Terrigenic 

helium 

(percent)

Apparent age of young 

groundwater estimated 

from atmospheric 

tracer data (years 

before sampling date)

Carbon-14 

(pmC)

Regional groundwater

ML 5 08-09-2011 -4±2.3 O nd nd nd

ML 6 08-08-2011 13.3±2.1 M nd nd nd

ML 12 08-09-2011 8.6±1.9 M nd nd nd

ML 17 06-04-2012 -0.1±2.1 O nd nd nd

ML 19 05-14-1997 53.1±1.9 Y 38 nd nd

ML 22 04-19-1995 55.6±0.2 Y 7 5 nd

ML 24 06-06-2012 9.7±2.2 M nd nd nd

ML 25 05-21-1997 2.2±1.0 O 89 nd nd

ML 29 06-12-1991 -22±13 O nd nd nd

ML 30 06-06-2012 9.7±2.2 M nd nd nd

ML 31 06-06-2012 4.7±2.1 M nd nd nd

Reno Ranch 06-28-2000 25.6±12.8 Y or M nd nd nd

USGS 101 04-21-1995 4.2±0.1 M 55 27–30 nd

Geothermal water

INEL-1 10,300 ft 04-19-1989 nd nd nd nd 235,000

ML 57 11-05-1990 0.4±0.3 O 96 nd nd

ML 58 06-05-2012 3.1±2.1 M or O nd nd nd

Groundwater at the Idaho National Laboratory

Deep groundwater

EBR 1 06-19-1991 -3.2±13 O or M 27 >45 nd

Site 9 07-22-1996 4.2±1.0 M or O 69 >35 nd

Site 14 10-13-1994 3.7±0.3 O 91 >40 48.0

USGS 7 10-14-1996 -0.2±0.1 O 97 >>55 nd

USGS 15 06-14-1995 1.76±0.03 O 82 22–26 42.76±0.31

Contaminated groundwater

Advanced Test Reactor Complex

USGS 65 05-16-1991 39,600±380 C nd nd nd

Idaho Nuclear Technology and Engineering Center

CFA 1 07-16-1996 19,500±160 C 32 C nd

CFA2 07-16-1996 14,100±1,400 C 15 C nd

USGS 20 05-30-1991 10,500±90 C nd nd nd

USGS 36 07-19-1996 5,200±800 C 6 C nd

USGS 57 05-13-1991 24,500±260 C nd nd nd

USGS 82 07-19-1996 1,130±160 C 21 27 nd

USGS 85 06-04-1991 16,800±130 C nd nd nd

USGS 104 07-15-1996 1,670±240 C nd >28 nd

USGS 105 04-18-1995 312.0±2.0 C 8 ? nd

USGS 108 04-18-1995 230±13 C nd >20 nd

USGS 109 10-04-1994 107.3±0.6 C 16 18–20 nd

USGS 112 07-15-1996 27,400±260 C 22 C nd

USGS 113 07-16-1996 10,800±1,200 C 22 C nd

USGS 115 07-15-1996 4,800±400 C 42 C nd

USGS 116 07-15-1996 3,800±300 C 32 C nd

USGS 124 07-20-1994 268.4±2.1 C 23 >24 nd
174 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 17. Activity of tritium and approximate age of water samples, calculated percentage of terrigenic helium, apparent age of young 

fraction of groundwater estimated from environmental tracer data, and activity of carbon-14, Idaho National Laboratory and vicinity, 

eastern Idaho.—Continued

Site name Date sampled Tritium

(pCi/L)

Approximate age 

of water sample 

based on tritium 

activity

Terrigenic 

helium 

(percent)

Apparent age of young 

groundwater estimated 

from atmospheric 

tracer data (years 

before sampling date)

Carbon-14 

(pmC)

Contaminated groundwater—Continued

Naval Reactors Facility

NRF 6 09-05-1996 89.6±12.8 C nd nd nd

NRF 9 09-04-1996 131.2±12.8 C nd nd nd

NRF 10 09-04-1996 144.0±12.8 C nd nd nd

NRF 11 09-05-1996 297.6±12.8 C nd nd nd

NRF 12 09-05-1996 76.8±12.8 C nd nd nd

NRF 13 09-05-1996 48.0±12.8 Y nd nd nd

Radioactive Waste Management Complex

RWMC M3S 07-22-1996 2,000±600 C 34 C nd

RWMC M7S 07-22-1996 1,600±400 C 25 C nd

RWMC Production 03-23-1989 1,700±200 C nd nd nd

USGS 87 04-05-1989 1,200±200 C nd ? nd

USGS 88 04-04-1989 90±160 ? nd ? nd

USGS 90 04-05-1989 1,600±200 C nd nd nd

USGS 120 07-17-1996 174.1±5.4 C 11 C nd

Test Area North

TAN Disposal 03-07-1989 27,600±220 C nd nd nd

TDD 1 03-02-1989 900±200 C nd nd nd

TDD 2 03-06-1989 3,100±200 C nd nd nd

USGS 24 02-28-1989 10,100±400 C nd nd nd

Natural groundwater

North INL Area

ANP 6 10-14-1994 3.2±0.1 O 15 20–30 30.91±0.28

ANP 8 12-13-1989 38±13 Y nd nd nd

IET 1 Disposal 07-21-1997 10±110 ? 18 >12 nd

No Name 1 10-13-1994 0.13±0.03 O 10 19–21 nd

PSTF Test 10-13-1994 2.5±0.1 O 1 <9 nd

TDD 3 12-13-1989 -3.2±13 O or M nd nd nd

Northeast INL Area

ANP 9 10-14-1994 0.2±0.2 O 67 6–7 nd

USGS 26 10-14-1994 0.0±0.1 O 86 5–6 53.3

USGS 27 10-11-1994 3.9±0.1 O 88 13 nd

USGS 29 06-15-1995 22.7±0.4 M 71 25 85.85±0.51

USGS 31 07-19-1996 -1.6±0.8 O 83 13 64.56±0.44

USGS 32 10-11-1994 1.2±0.1 O 35 5 62.28±0.43

Southeast INL Area

Arbor Test 1 04-21-1995 12.5±0.1 M 46 13–25 nd

Area II 07-18-1996 12.5±1.0 M 72 20–21 nd

Atomic City 10-03-1994 11.9±0.3 M 24 14–19 nd

Leo Rogers 1 07-17-1996 12.5±1.3 M 36 nd nd

USGS 1 10-09-1996 5.8±1.0 M 60 18–24 71.6

USGS 2 07-17-1996 12.2±1.3 M 34 18–24 nd

USGS 14 10-26-1994 19.2±0.1 M 13 >27 58.6

USGS 100 04-21-1995 14.0±0.3 M 53 17–21 79.83±0.50

USGS 107 10-09-1996 10.2±1.0 M 33 >15 nd

USGS 110A 10-09-1996 10.9±1.0 M 55 16–20 nd
Tables 10–17 175

Table 17. Activity of tritium and approximate age of water samples, calculated percentage of terrigenic helium, apparent age of young 

fraction of groundwater estimated from environmental tracer data, and activity of carbon-14, Idaho National Laboratory and vicinity, 

eastern Idaho.—Continued

Site name Date sampled Tritium

(pCi/L)

Approximate age 

of water sample 

based on tritium 

activity

Terrigenic 

helium 

(percent)

Apparent age of young 

groundwater estimated 

from atmospheric 

tracer data (years 

before sampling date)

Carbon-14 

(pmC)

Natural groundwater—Continued

Central INL Area

Badging Facility Well 07-16-1996 22.7±1.3 M 0 20–30? nd

NPR Test 10-10-1996 57.4±0.2 Y 8 25? 78.25

USGS 5 10-12-1994 28.4±0.4 M 30 17–18 nd

USGS 6 07-18-1996 0.3±0.8 O 62 >>55 nd

USGS 17 06-13-1995 50.0±0.5 Y 27 11–16 82.90±0.47

USGS 18 07-18-1994 0.5±0.5 O 84 17 20.58

USGS 83 04-17-1995 -190±70 O nd 34-35 nd

USGS 103 04-18-1995 11.8±0.1 M 16 >26 nd

Northwest INL Area

Fire Station 2 10-16-1996 36.5±1.6 Y 9 11-20 nd

INEL-1 WS 06-12-1995 48.3±1.9 Y nd 20-21 59.48±0.55

NRF 7 09-03-1996 12.8±12.8 O or M nd nd nd

NRF 8 09-04-1996 57.6±12.8 Y nd nd nd

Site 4 10-16-1996 51.5±1.9 Y 4 25 nd

Site 17 06-18-1991 32±13 Y or M 1 21-22 53.99±0.39

Site 19 07-16-1996 13.4±1.0 M 7 15 nd

USGS 12 06-14-1995 71.9±0.7 Y 6 3–17 85.21±0.47

USGS 19 04-19-1995 11.8±0.3 M 38 15–16 36.99

USGS 22 06-13-1995 160.9±0.4 Y 0 8 69.91±0.52

USGS 23 04-19-1995 1.3±0.1 O 57 >>55 21.88±0.24

USGS 97 06-13-1995 69.0±1.0 Y 6 10–20 84.42±0.53

USGS 98 10-04-1994 20.0±0.4 M 2 10–20 63.17±0.44

USGS 99 06-12-1995 36.2±0.5 Y 9 10–20 76.30±0.51

USGS 102 06-13-1995 70.8±0.6 Y 10 26? 86.17±0.52

USGS 134 (sz) 09-04-2008 17±1.9 M nd nd nd

Southwest INL Area

Middle 2051 (sz) 08-25-2008 51.7±2.9 Y nd nd nd

USGS 8 10-04-1994 47.4±0.5 Y 10 8–9 nd

USGS 9 10-04-1994 47.9±0.2 Y 23 >23 nd

USGS 11 04-20-1995 31.8±0.2 Y 13 >17 65.0

USGS 86 10-11-1996 2.9±1.0 O 40 12–19 nd

USGS 89 10-14-1998 10±49 M or Y 28 ? nd

USGS 117 07-17-1996 -100±100 O 33 >33 nd

USGS 119 04-03-1989 -70±150 ? nd ? nd

USGS 125 06-16-1995 72.8±0.6 Y 14 >17 76.65±0.46

USGS 135 (sz) 09-14-2010 14±1.9 M nd nd nd

1

Estimated pmC, based on typical carbon-14 activity of atmospheric carbon dioxide during the 1980s and 1990s (Plummer, Sanford, and others, 2004, fig. 98).

2

Estimated age in years (Mann, 1986).
176 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho
Glossary 177

Glossary

Contaminated groundwater Groundwater 

at the Idaho National Laboratory probably 

influenced by wastewater disposal. 

Contaminated groundwater was identified 

from various chemical signatures. These 

included groundwater samples with (1) 

large tritium activities (>75 pCi/L); (2) large 

sodium and sulfate concentrations (>25 and 

>40 mg/L, respectively); (3) large specific 

conductance values (>600 μS/cm at 25 °C); 

and (4) in the area near the Naval Reactors 

Facility, large chloride/nitrate ratios (>75).

Deep groundwater Groundwater at the 

Idaho National Laboratory that is more than 

the 250 ft below the water table (does not 

include geothermal water).

Environmental tracers Refers to tritium 

(3H), carbon-14 (14C), chlorofluorocarbons 

(CFCs), sulfur hexafluoride (SF6), and the 

ratio tritium/helium-3 (3H/3He). Radioactive 

isotopes 3H and 14C are used to date 

groundwater (Clark and Fritz, 1997); the 

age of the young fraction of groundwater 

was determined from CFCs, SF6, and 3H/3He 

(Busenberg and others, 2001).

Geothermal water Groundwater in the study 

area with temperatures exceeding 25 °C.

Groundwater at the Idaho National Laboratory 

(INL) Deep groundwater, contaminated 

groundwater, and natural groundwater.

Modern activity of carbon-14 (14C) Percent 

modern carbon (pmC) values greater than 100 

and indicates a post-1950 age of groundwater.

Natural groundwater Groundwater at and 

south of the Idaho National Laboratory, 

excluding contaminated groundwater, that is 

less than the 250 ft below the water table.

Old groundwater Groundwater that is older 

than the onset of atmospheric bomb testing 

(pre-1952). In this report, this qualitative age 

was assigned to groundwater with tritium 

activities less than 4 pCi/L.

Recent recharge Generally refers to 

groundwater that has recharged since CFCs 

were introduced into the atmosphere (about 

1940). When in reference to groundwater 

with a Heterr less than 10 percent, refers to 

groundwater that has been in contact with air 

or the unsaturated-zone atmosphere within the 

past several hundred years (Busenberg and 

others, 2001).

Regional groundwater Groundwater in the 

eastern Snake River Plain aquifer east and 

southeast of the Idaho National Laboratory. 

Includes ML 22, USGS 3A, and USGS 101 in 

the southeastern part of the INL.

Sources of recharge Sources of recharge 

include surface water, tributary valley 

groundwater, regional groundwater, 

geothermal water, precipitation, industrial 

wastewater discharge, and agricultural 

return flows.

Tributary valley groundwater Groundwater 

from the Big Lost River, Little Lost River, 

and Birch Creek valleys. Includes two 

groundwater samples (ML 55 and ML 59) 

from the Beaverhead Mountains.

Young fraction of groundwater Water that 

has recharged since the 1940s.

Young groundwater Groundwater that 

is younger than the onset of atmospheric 

bomb testing (post-1952). This qualitative 

groundwater age was determined from tritium 

activities.
178 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho
Appendix 1 179

Appendix 1. Water-Level Measurements
180 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 1-1. Water-level measurements used to construct water-table contours, Idaho National Laboratory and vicinity, eastern Idaho.

[Water-level measurements are from U.S. Geological Survey (2014). Water-table contours are shown in figure 6. Site name: –, no name. Altitudes: In feet (ft) 

above National Geodetic Vertical Datum of 1929 (NGVD 29). Abbreviations: ft bls, feet below land surface; NAD 27, North American Datum of 1927]

USGS site 

No.

USGS station 

No.

Site 

name

Latitude 

(NAD 27)

Longitude 

(NAD 27)

Altitude

(ft)

Water-level 

measurement 

date

Water 

level

(ft bls)

Waterlevel 

altitude

(ft)

431517112190101 02S 35E 11DDD1 – 431517.00 1121901.00 4,518.38 03-29-1989 49.98 4,468.40

431517112190102 02S 35E 11DDD2 – 431517.00 1121901.00 4,518.38 03-29-1989 70.23 4,448.15

431520112360901 02S 33E 16ABB1 – 431520.00 1123608.50 4,556.00 03-29-1989 133.95 4,422.05

431902112284301 01S 34E 21DAC1 – 431859.80 1122842.60 4,547.00 03-29-1989 111.32 4,435.68

431929112421701 01S 32E 22BDB1 – 431928.40 1124220.20 4,740.00 03-29-1989 318.29 4,421.71

431946113161401 01S 27E 14DCC1 SITE 2 431946.00 1131614.00 5,158.86 04-11-1989 995.74 4,163.12

432019112563201 01S 30E 15BCA1 USGS 14 432019.27 1125631.92 5,132.88 05-01-1989 714.66 4,418.22

432042112193201 01S 35E 11CAD1 – 432042.00 1121931.00 4,662.00 03-29-1989 172.93 4,489.07

432336113064201 01N 29E 30BBD1 USGS 11 432336.18 1130642.52 5,067.12 05-01-1989 651.03 4,416.09

432618112555501 01N 30E 10BBA1 Cerro Grande 432618.00 1125553.86 4,979.30 05-01-1989 552.43 4,426.87

432659112582601 02N 29E 35CCC1 USGS 108 432658.79 1125826.34 5,031.36 04-19-1989 604.86 4,426.50

432700112470801 02N 31E 35DCC1 USGS 1 432700.08 1124708.54 5,022.34 04-27-1989 586.24 4,436.10

432701113025601 02N 29E 31CDC1 USGS 109 432701.23 1130255.81 5,043.64 04-21-1989 619.08 4,424.56

432703113001801 02N 29E 33DCC1 USGS 105 432703.40 1130017.78 5,095.12 04-21-1989 668.36 4,426.76

432714112560701 02N 30E 31CBC1 USGS 103 432713.57 1125606.53 5,007.42 04-14-1989 580.22 4,427.20

432717112501501 02N 30E 35DAD1 USGS 110 432716.97 1125015.05 4,999.91 04-12-1989 567.75 4,432.16

432731113143902 02N 27E 33ACC2 USGS 13 432730.57 1131438.51 5,374.58 05-01-1989 984.61 4,389.97

432740113044501 02N 28E 35AAC1 USGS 9 432732.38 1130439.78 5,030.32 04-21-1989 605.84 4,424.48

432854113201001 02N 26E 22DDA1 – 432854.00 1132010.00 5,361.81 04-11-1989 660.07 4,701.74

432854113201002 02N 26E 22DDA2 – 432854.00 1132010.00 5,361.81 04-11-1989 981.21 4,380.60

432856112560801 02N 29E 24DAD1 USGS 104 432856.07 1125608.14 4,987.64 04-14-1989 553.95 4,433.69

432919113031501 02N 29E 19BCB1 USGS 120 432919.19 1130314.01 5,040.43 04-04-1989 613.12 4,427.31

432935113080001 02N 28E 21BBB1 USGS 86 432934.79 1130801.44 5,076.92 04-21-1989 649.12 4,427.80

432940113030201 02N 29E 18CCD1 USGS 88 432940.20 1130301.96 5,020.81 04-04-1989 582.83 4,437.98

432942112532801 02N 30E 16CCA1 USGS 107 432942.02 1125327.53 4,917.50 04-11-1989 477.66 4,439.84

432945113023401 02N 29E 18DCB1 USGS 119 432944.61 1130233.69 5,031.84 04-03-1989 602.22 4,429.62

432954113020501 02N 29E 17CBC1 USGS 90 432952.45 1130205.86 5,010.01 01-18-1989 580.67 4,429.34

432955113025901 02N 29E 18CBD1 USGS 117 432954.50 1130258.67 5,012.50 04-03-1989 582.89 4,429.61

432959112593101 02N 29E 15CBA1 USGS 106 432958.60 1125931.38 5,015.30 04-14-1989 586.19 4,429.11

433005113032801 02N 28E 13ADD1 USGS 89 433005.67 1130331.73 5,030.24 04-04-1989 598.29 4,431.95

433013113024201 02N 29E 18BDA1 USGS 87 433012.74 1130243.06 5,017.85 04-05-1989 586.77 4,431.08

433023112561501 02N 29E 13AAA1 USGS 83 433023.03 1125615.28 4,941.11 04-13-1989 495.53 4,445.58

433121113115801 02N 27E 02DDC1 USGS 8 433120.51 1131157.43 5,194.94 05-01-1989 764.43 4,430.51

433123112530101 02N 30E 04DCC1 Site 9 433122.86 1125300.80 4,925.65 04-05-1989 469.80 4,455.85

433144112563501 02N 29E 01DBB1 CFA 2 433143.94 1125635.11 4,931.70 01-25-1989 474.55 4,457.15

433216112563201 03N 29E 36DCD1 CFA LF 2-8 433216.00 1125632.00 4,932.88 01-19-1989 471.93 4,460.95

433216112563301 03N 29E 36DCC2 CFA LF 2-10 433215.87 1125632.97 4,932.03 01-26-1989 475.50 4,456.53

433217112563401 03N 29E 36DCC1 CFA LF 2-9 433217.00 1125634.00 4,933.37 01-26-1989 469.88 4,463.49

433218112191601 02N 35E 02BBC1 Highway 1C 433218.00 1121916.00 5,089.83 04-08-1989 578.31 4,511.52

433218112571001 03N 29E 36CCB1 CFA LF 3-8 433218.00 1125710.00 4,941.43 01-19-1989 480.32 4,461.11

433223112470201 03N 31E 35DCA1 Area II 433222.62 1124702.40 5,128.60 03-29-1989 667.05 4,461.55

433230112561701 03N 29E 36DAC1 CFA LF 2-11 433230.40 1125617.01 4,928.37 12-06-1989 470.20 4,458.17

433246112571201 03N 29E 36BCB1 USGS 85 433246.23 1125711.89 4,938.99 04-01-1989 479.37 4,459.62

433253112545901 03N 30E 31AAD1 USGS 20 433252.79 1125459.41 4,915.11 04-01-1989 457.89 4,457.22

433303112184201 03N 35E 35BAD1 – 433302.50 1121842.40 5,160.00 04-11-1989 645.20 4,514.80

433307112300001 03N 34E 32BBC1 Highway 2 433307.00 1123000.00 5,216.55 04-08-1989 720.39 4,496.16

433314112561801 03N 29E 25DDB1 USGS 113 433314.53 1125618.29 4,925.32 03-31-1989 464.27 4,461.05

433314112563001 03N 29E 25DCA1 USGS 112 433314.50 1125630.74 4,927.82 03-30-1989 467.98 4,459.84

433315112560301 03N 30E 30CCB1 USGS 77 433315.25 1125603.57 4,921.43 03-31-1989 461.68 4,459.75

433318112555001 03N 30E 30CBD1 USGS 114 433318.87 1125550.75 4,920.04 03-31-1989 460.10 4,459.94

433320112432301 03N 32E 29DDC1 USGS 2 433319.87 1124321.28 5,125.22 04-27-1989 655.49 4,469.73
Appendix 1 181

Table 1-1. Water-level measurements used to construct water-table contours, Idaho National Laboratory and vicinity, eastern 

Idaho.—Continued

USGS site 

No.

USGS station 

No.

Site 

name

Latitude 

(NAD 27)

Longitude 

(NAD 27)

Altitude

(ft)

Water-level 

measurement 

date

Water 

level

(ft bls)

Waterlevel 

altitude

(ft)

433320112554101 03N 30E 30CAD1 USGS 115 433320.22 1125541.39 4,918.86 04-06-1989 459.25 4,459.61

433322112564301 03N 29E 25CAD1 USGS 38 433322.35 1125643.25 4,929.04 03-31-1989 469.06 4,459.98

433326112564801 03N 29E 25CAA1 USGS 37 433325.80 1125648.13 4,928.54 03-31-1989 468.60 4,459.94

433330112565201 03N 29E 25BDD1 USGS 36 433330.11 1125651.47 4,928.83 03-31-1989 468.90 4,459.93

433331112553201 03N 30E 30ACC1 USGS 116 433331.55 1125532.67 4,916.05 04-06-1989 455.88 4,460.17

433331112560501 03N 30E 30BCC1 USGS 111 433331.16 1125605.18 4,920.48 04-06-1989 461.51 4,458.97

433334112565501 03N 29E 25BDC1 USGS 34 433334.44 1125654.76 4,928.54 03-31-1989 468.71 4,459.83

433339112565801 03N 29E 25BDB1 USGS 35 433338.37 1125658.14 4,928.97 03-31-1989 469.47 4,459.50

433343112570001 03N 29E 25BBD1 USGS 39 433343.19 1125701.42 4,930.55 03-31-1989 470.85 4,459.70

433344112554101 03N 30E 30BAD1 USGS 67 433344.09 1125540.72 4,913.34 04-10-1989 453.59 4,459.75

433344112562601 03N 29E 25ABD1 USGS 57 433344.04 1125626.00 4,922.23 04-07-1989 462.53 4,459.70

433350112560601 03N 30E 30BBB1 USGS 51 433350.01 1125606.06 4,916.91 04-17-1989 455.19 4,461.72

433354112554701 03N 30E 30BAB1 USGS 59 433354.32 1125548.02 4,912.88 04-10-1989 452.28 4,460.60

433356112574201 03N 29E 23DCD1 USGS 84 433356.51 1125741.84 4,937.63 04-01-1989 477.68 4,459.95

433401112551001 03N 30E 19DDC2 USGS 82 433400.93 1125510.34 4,906.83 04-13-1989 446.15 4,460.68

433401112560301 03N 30E 19CCC1 USGS 48 433400.62 1125602.52 4,916.84 04-06-1989 456.06 4,460.78

433402112561801 03N 29E 24DDC1 USGS 45 433402.35 1125617.76 4,917.69 04-07-1989 457.78 4,459.91

433403112555401 03N 30E 19CCA1 USGS 49 433402.91 1125554.13 4,913.67 04-07-1989 452.97 4,460.70

433404112561301 03N 29E 24DDA2 USGS 42 433402.76 1125611.73 4,916.87 04-07-1989 456.11 4,460.76

433407112203101 03N 35E 28AAA1 – 433407.00 1122031.00 5,195.00 04-10-1989 681.35 4,513.65

433407112560301 03N 30E 19CCB1 USGS 47 433407.51 1125603.13 4,915.63 04-20-1989 453.77 4,461.86

433407112561501 03N 29E 24DDA3 USGS 46 433406.55 1125614.68 4,916.42 04-07-1989 455.87 4,460.55

433409112561301 03N 29E 24DDA1 USGS 41 433407.70 1125611.78 4,916.26 04-07-1989 455.49 4,460.77

433409112562101 03N 29E 24DDB1 USGS 44 433408.61 1125621.15 4,917.73 04-07-1989 456.90 4,460.83

433411112561101 03N 29E 24DAD1 USGS 40 433411.68 1125611.83 4,915.65 03-27-1989 455.44 4,460.21

433414112554201 03N 30E 19CAC1 USGS 52 433414.74 1125544.26 4,909.44 04-07-1989 448.57 4,460.87

433415112561501 03N 29E 24DAD2 USGS 43 433414.79 1125614.82 4,915.48 04-20-1989 454.78 4,460.70

433422113031701 03N 29E 19CBB1 USGS 22 433422.28 1130321.09 5,048.27 04-05-1989 608.09 4,440.18

433425112573201 03N 29E 23ADC1 USGS 76 433425.31 1125732.31 4,929.74 04-07-1989 469.84 4,459.90

433447112574501 03N 29E 23ABB1 USGS 65 433446.85 1125747.13 4,924.75 04-10-1989 463.56 4,461.19

433449112523101 03N 30E 16DDD1 NPR Test 433449.43 1125231.26 4,933.13 04-28-1989 458.60 4,474.53

433500112182201 03N 35E 14DDC1 – 433500.00 1121822.00 5,057.00 04-11-1989 532.45 4,524.55

433500112572502 03N 29E 14DDA2 USGS 58 433500.19 1125725.07 4,918.11 04-13-1989 457.16 4,460.95

433503112400701 03N 32E 14CDD1 USGS 100 433502.72 1124006.67 5,157.94 04-19-1989 672.67 4,485.27

433505112581901 03N 29E 14CBD1 USGS 79 433505.49 1125819.11 4,930.50 04-01-1989 469.80 4,460.70

433509112384801 03N 32E 13DCA1 Arbor Test I 433508.92 1123848.01 5,163.95 04-27-1989 675.57 4,488.38

433520112572601 03N 29E 14ADD1 MTR Test 433520.08 1125729.20 4,916.47 03-27-1989 455.15 4,461.32

433522112582101 03N 29E 14BCB1 Site19 433522.32 1125821.49 4,925.95 04-10-1989 464.97 4,460.98

433543112493801 03N 30E 12CDD1 USGS 5 433542.75 1124937.65 4,937.57 03-28-1989 462.86 4,474.71

433545112391501 03N 32E 13BBD1 Site 16 433544.69 1123915.42 5,121.23 03-20-1989 632.69 4,488.54

433643112210401 03N 35E 09BAA1 – 433643.00 1122104.00 5,119.00 04-12-1989 596.42 4,522.58

433657112563601 03N 29E 01DBB1 USGS 98 433657.00 1125636.00 4,882.64 04-19-1989 399.75 4,482.89

433658112173201 03N 35E 01CAD1 – 433657.00 1121736.00 4,948.00 04-12-1989 425.68 4,522.32

433705112552101 03N 30E 06ACD1 USGS 99 433703.74 1125521.16 4,871.55 04-19-1989 388.42 4,483.13

433716112563601 03N 29E 01ABC1 INEL 1 WS 433714.54 1125639.90 4,872.23 04-19-1989 389.12 4,483.11

433718112190801 03N 35E 02BCB1 – 433723.00 1121910.00 5,035.00 04-12-1989 502.95 4,532.05

433745112172701 04N 35E 36DCB1 – 433748.00 1121729.00 4,930.00 04-14-1989 402.11 4,527.89

433748112151201 04N 36E 32CDA1 – 433748.00 1121512.00 4,860.00 04-19-1989 340.00 4,520.00

433759112202701 04N 35E 34CBB1 – 433759.00 1122027.00 5,040.00 04-12-1989 514.90 4,525.10

433802112192401 04N 35E 34ADD1 – 433801.00 1121929.00 5,010.00 04-13-1989 483.78 4,526.22

433807112551501 04N 30E 31ABD1 USGS 97 433806.77 1125516.76 4,858.49 04-19-1989 373.95 4,484.54

433819113191601 04N 26E 26DCD1 – 433818.99 1131919.46 5,332.25 03-31-1989 48.87 5,283.38
182 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 1-1. Water-level measurements used to construct water-table contours, Idaho National Laboratory and vicinity, eastern 

Idaho.—Continued

USGS site 

No.

USGS station 

No.

Site 

name

Latitude 

(NAD 27)

Longitude 

(NAD 27)

Altitude

(ft)

Water-level 

measurement 

date

Water 

level

(ft bls)

Waterlevel 

altitude

(ft)

433853112551601 04N 30E 30ACA1 USGS 102 433850.87 1125516.43 4,850.28 12-20-1989 367.72 4,482.56

433900112145901 04N 36E 29ACD1 – 433900.00 1121459.00 4,895.00 04-12-1989 370.35 4,524.65

433906112165601 04N 35E 25ADA1 – 433906.00 1121656.00 4,958.00 04-15-1989 425.19 4,532.81

433937112515401 04N 30E 22BDD1 USGS 17 433936.42 1125154.27 4,833.44 04-08-1989 349.12 4,484.32

433945112221701 04N 35E 20CAA1 – 433946.00 1122217.00 5,030.00 04-13-1989 503.61 4,526.39

434027112575701 04N 29E 14CAA1 Site 17 434026.74 1125756.50 4,880.47 03-28-1989 390.17 4,490.30

434031112453701 04N 31E 16ADC1 USGS 6 434031.12 1124536.66 4,898.55 05-22-1989 410.51 4,488.04

434037112193501 04N 35E 15DBA1 – 434037.00 1121935.00 4,981.00 04-15-1989 450.78 4,530.22

434040112163501 04N 36E 18BDC1 – 434040.00 1121635.00 4,898.00 04-19-1989 364.64 4,533.36

434055112595901 04N 29E 09DCD1 USGS 23 434055.15 1130000.02 4,884.20 03-29-1989 393.10 4,491.10

434117112191801 04N 35E 10DAD1 – 434117.00 1121918.00 4,995.00 04-17-1989 458.45 4,536.55

434126112550701 04N 30E 07ADB1 USGS 12 434126.19 1125507.10 4,819.00 04-15-1989 322.06 4,496.94

434234112551701 04N 30E 06ABA1 USGS 15 434234.84 1125517.35 4,811.99 03-28-1989 312.73 4,499.26

434307112382601 05N 32E 36ADD1 USGS 21 434307.49 1123825.90 4,838.70 04-15-1989 327.91 4,510.79

434327112161101 05N 36E 31ACB1 – 434327.00 1121611.00 4,880.00 04-18-1989 316.71 4,563.29

434334112463101 05N 31E 28CCC1 Site 14 434334.66 1124631.50 4,793.52 04-18-1989 263.42 4,530.10

434407112285101 05N 34E 29DAA1 USGS 29 434406.86 1122850.25 4,877.48 04-26-1989 349.60 4,527.88

434426112575701 05N 29E 23CDD1 USGS 19 434426.68 1125756.58 4,800.06 04-15-1989 272.43 4,527.63

434444112322101 05N 33E 23DDA1 USGS 32 434444.07 1123221.24 4,812.02 04-17-1989 284.82 4,527.20

434540112440901 05N 31E 14BCC1 USGS 18 434540.70 1124409.29 4,804.23 03-29-1989 264.67 4,539.56

434600112360101 05N 33E 17ADD1 USGS 28 434559.97 1123600.53 4,771.48 04-17-1989 226.94 4,544.54

434601112315401 05N 33E 13BDC1 USGS 30C 434600.72 1123154.36 4,793.87 04-26-1989 264.67 4,529.20

434611112504301 05N 30E 11CDD1 DH 1B 434611.02 1125043.22 4,792.12 05-19-1989 264.26 4,527.86

434624112194601 05N 35E 10DCC1 – 434622.70 1121956.60 4,900.00 04-13-1989 258.84 4,641.16

434657112282201 05N 34E 09BDA1 USGS 4 434655.93 1122821.62 4,790.73 04-16-1989 256.40 4,534.33

434701112214301 05N 35E 08AAD1 – 434701.00 1122143.00 4,790.00 04-11-1989 250.13 4,539.87

434713112222301 05N 35E 08BAA1 – 434713.00 1122223.00 4,790.00 04-11-1989 246.09 4,543.91

434714112175801 05N 35E 01CCC1 – 434714.00 1121758.00 4,793.00 04-13-1989 236.09 4,556.91

434714112231101 05N 35E 06DDC1 – 434713.50 1122314.40 4,789.00 04-11-1989 248.29 4,540.71

434718112290501 05N 34E 05DDC1 – 434718.00 1122910.70 4,790.00 08-28-1989 249.45 4,540.55

434726112200801 05N 35E 03CDB1 – 434726.00 1122008.00 4,792.00 04-13-1989 247.92 4,544.08

434726112244101 05N 34E 01DBC1 – 434729.00 1122435.00 4,786.00 04-12-1989 246.78 4,539.22

434731112282901 05N 34E 04CAC1 – 434731.00 1122829.00 4,788.00 08-28-1989 260.08 4,527.92

434734112241401 05N 34E 01DAB1 – 434734.00 1122414.00 4,787.00 04-12-1989 248.21 4,538.79

434736112253001 05N 34E 02DAB1 – 434733.00 1122535.00 4,790.00 04-12-1989 251.95 4,538.05

434738112273901 05N 34E 04DAA1 – 434738.00 1122739.00 4,790.00 08-28-1989 258.68 4,531.32

434741112291101 05N 34E 05DAB1 – 434733.00 1122907.00 4,789.00 04-16-1989 253.25 4,535.75

434744112193701 05N 35E 03ACD1 – 434744.00 1121937.00 4,801.00 04-12-1989 251.97 4,549.03

434744112212203 05N 35E 04BDB3 – 434744.00 1122122.00 4,789.00 04-11-1989 244.39 4,544.61

434751112571801 05N 29E 01BBB1 – 434751.00 1125718.00 4,805.00 03-29-1989 122.83 4,682.17

434756112212101 06N 35E 32DDD1 – 434756.00 1122121.00 4,789.00 04-17-1989 243.83 4,545.17

434805112204501 06N 35E 33CDA1 – 434805.00 1122045.00 4,792.28 04-10-1989 245.07 4,547.21

434805112303501 06N 34E 31CDB1 – 434805.00 1123035.00 4,785.00 04-15-1989 257.68 4,527.32

434810112230401 06N 35E 31DBC1 – 434810.00 1122304.00 4,785.00 04-11-1989 239.53 4,545.47

434817112292101 06N 34E 32CAB1 – 434817.00 1122921.00 4,786.00 04-16-1989 250.67 4,535.33

434818112240401 06N 34E 36DBA1 – 434818.00 1122404.00 4,785.00 04-12-1989 248.53 4,536.47

434818112284801 06N 34E 32ACD1 – 434818.00 1122848.00 4,788.00 04-16-1989 251.10 4,536.90

434819112380501 06N 32E 36ADD1 2nd Owsley 434819.82 1123806.05 4,784.80 04-26-1989 218.07 4,566.73

434824112214901 06N 35E 32ACC1 – 434824.00 1122149.00 4,788.00 04-11-1989 238.00 4,550.00

434828112185001 06N 35E 35BCB1 – 434828.00 1121850.00 4,802.95 04-12-1989 239.66 4,563.29

434831112273601 06N 34E 33ADB1 – 434831.00 1122736.00 4,790.00 08-31-1989 257.24 4,532.76

434831112303501 06N 34E 31BDB1 – 434831.00 1123035.00 4,785.00 08-24-1989 248.66 4,536.34
Appendix 1 183

Table 1-1. Water-level measurements used to construct water-table contours, Idaho National Laboratory and vicinity, eastern 

Idaho.—Continued

USGS site 

No.

USGS station 

No.

Site 

name

Latitude 

(NAD 27)

Longitude 

(NAD 27)

Altitude

(ft)

Water-level 

measurement 

date

Water 

level

(ft bls)

Waterlevel 

altitude

(ft)

434842112210601 06N 35E 33BBA1 – 434842.00 1122106.00 4,788.00 04-10-1989 240.07 4,547.93

434843112271601 06N 34E 34BBB1 – 434844.00 1122720.00 4,790.00 04-16-1989 251.07 4,538.93

434851112321801 06N 33E 26DDB1 USGS 27 434851.22 1123218.90 4,783.90 04-15-1989 219.89 4,564.01

434856112400001 06N 32E 26CDB1 ANP 9 434855.71 1124000.36 4,786.14 03-01-1989 216.48 4,569.66

434857112185801 06N 35E 27DDA1 – 434857.00 1121858.00 4,798.23 04-12-1989 234.60 4,563.63

434858112295901 06N 34E 30DAC1 – 434858.00 1122959.00 4,786.00 04-16-1989 217.65 4,568.35

434905112213801 06N 35E 29DBA1 – 434905.00 1122138.00 4,786.00 04-10-1989 238.86 4,547.14

434915112443901 06N 31E 27BDD1 USGS 7 434914.81 1124439.87 4,789.24 03-30-1989 206.05 4,583.19

434924112183701 06N 35E 26BAC1 – 434924.00 1121837.00 4,790.59 04-13-1989 218.05 4,572.54

434924112193101 06N 35E 27ABC1 – 434924.00 1121931.00 4,796.00 04-13-1989 237.29 4,558.71

434935112210701 06N 35E 28BBA1 – 434934.00 1122106.00 4,785.00 04-10-1989 233.20 4,551.80

434938112200701 06N 35E 22CCC1 – 434938.00 1122007.00 4,788.00 04-11-1989 234.07 4,553.93

434939112174501 06N 35E 23DDD1 – 434939.00 1121745.00 4,833.00 04-13-1989 178.68 4,654.32

434941112454201 06N 31E 21DCC1 PSTF Test 434940.74 1124541.46 4,786.35 05-19-1989 201.95 4,584.40

434949112413401 06N 32E 22CCB1 GIN 2 434948.89 1124133.96 4,786.23 04-27-1989 202.74 4,583.49

434950112311201 06N 33E 24DDB1 – 434950.00 1123112.00 4,785.00 04-18-1989 197.70 4,587.30

435003112313101 06N 33E 24BDD1 – 435002.30 1123134.80 4,785.00 04-18-1989 213.45 4,571.55

435016112182701 06N 35E 23BAD1 – 435016.00 1121830.00 4,790.14 04-13-1989 176.66 4,613.48

435016112311201 06N 33E 24AAC1 – 435016.00 1123112.00 4,785.00 04-18-1989 148.85 4,636.15

435028112194801 06N 35E 22BAB1 – 435028.00 1121948.00 4,786.00 04-11-1989 101.64 4,684.36

435028112202601 06N 35E 21AAB1 – 435028.00 1122026.00 4,784.50 04-10-1989 99.45 4,685.05

435028112245601 06N 34E 23AAA1 – 435028.00 1122456.00 4,787.00 04-18-1989 220.88 4,566.12

435038112453401 06N 31E 16DCA1 No Name 1 435038.79 1124532.76 4,784.30 05-19-1989 200.35 4,583.95

435042112182001 06N 35E 14CAD1 – 435041.00 1121824.00 4,789.00 04-13-1989 100.62 4,688.38

435045112180901 06N 35E 14DBD1 – 435045.00 1121809.00 4,789.00 04-19-1989 97.95 4,691.05

435050112423202 06N 31E 13CAB6 TAN 11 435050.00 1124232.00 4,781.84 12-14-1989 196.88 4,584.96

435053112420801 06N 31E 13DBB1 USGS 24 435050.77 1124212.34 4,795.10 04-15-1989 209.23 4,585.87

435053112423202 06N 31E 13CAB3 TAN 9 435053.00 1124232.00 4,781.91 12-11-1989 197.06 4,584.85

435100112271601 06N 34E 15BCC1 – 435100.00 1122716.00 4,784.75 04-18-1989 199.60 4,585.15

435107112180001 06N 35E 14ACA1 – 435108.00 1121804.00 4,790.00 04-19-1989 96.64 4,693.36

435108112172601 06N 35E 13BCA1 – 435108.00 1121726.00 4,810.00 04-19-1989 113.68 4,696.32

435108112185601 06N 35E 15AAD1 – 435108.00 1121856.00 4,787.85 04-14-1989 93.16 4,694.69

435120112182001 06N 35E 14BAA1 – 435120.00 1121820.00 4,789.00 04-14-1989 94.04 4,694.96

435123112163201 06N 35E 12DDD1 – 435123.00 1121632.00 4,850.00 04-14-1989 148.96 4,701.04

435124112433701 06N 31E 11CDC1 FET Disposal 3 435124.31 1124337.20 4,782.39 05-19-1989 196.10 4,586.29

435132112234001 06N 35E 07CCB1 – 435132.00 1122340.00 4,783.71 04-10-1989 198.27 4,585.44

435134112335501 06N 33E 10DBC1 ML 15 435134.00 1123357.50 4,783.00 04-18-1989 96.55 4,686.45

435140112155401 06N 36E 07DBC1 – 435140.00 1121554.00 4,851.00 04-14-1989 146.28 4,704.72

435152112443101 06N 31E 10ACC1 ANP 6 435151.57 1124431.39 4,794.43 05-19-1989 208.24 4,586.19

435153112320801 06N 33E 11ADD1 – 435153.00 1123208.00 4,783.00 04-18-1989 119.06 4,663.94

435153112420501 06N 31E 12ACD1 IET 1 Disposal 435153.38 1124205.22 4,790.02 03-01-1989 204.15 4,585.87

435200112164801 06N 35E 12ADB1 – 435200.00 1121648.00 4,795.00 04-14-1989 89.52 4,705.48

435201112194901 06N 35E 10BDD1 – 435200.00 1121954.00 4,785.00 04-11-1989 101.94 4,683.06

435212112311301 06N 33E 01DCD1 – 435214.00 1123113.00 4,784.00 04-18-1989 118.55 4,665.45

435212112394001 06N 32E 11ABA1 USGS 26 435210.55 1123940.74 4,788.69 04-27-1989 202.48 4,586.21

435213112302001 06N 34E 07BAA1 – 435213.00 1123020.00 4,784.00 04-18-1989 106.24 4,677.76

435226112150101 06N 36E 05CDB1 – 435226.00 1121501.00 4,850.00 04-20-1989 131.86 4,718.14

435226112172301 06N 35E 01CDB1 – 435226.00 1121723.00 4,790.00 04-14-1989 89.40 4,700.60

435229112163202 06N 35E 01DAD2 – 435227.90 1121635.90 4,795.00 04-14-1989 82.90 4,712.10

435230112161301 06N 36E 06CAC1 – 435230.00 1121613.00 4,815.00 04-19-1989 111.00 4,704.00

435252112150301 06N 36E 05BCA1 – 435252.00 1121503.00 4,819.00 04-20-1989 99.15 4,719.85

435253112161201 06N 36E 06BDB1 – 435253.00 1121612.00 4,792.00 04-20-1989 75.36 4,716.64
184 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 1-1. Water-level measurements used to construct water-table contours, Idaho National Laboratory and vicinity, eastern 

Idaho.—Continued

USGS site 

No.

USGS station 

No.

Site 

name

Latitude 

(NAD 27)

Longitude 

(NAD 27)

Altitude

(ft)

Water-level 

measurement 

date

Water 

level

(ft bls)

Waterlevel 

altitude

(ft)

435253112172701 06N 35E 01BBD1 – 435253.00 1121727.00 4,790.00 04-19-1989 70.10 4,719.90

435304112280801 06N 34E 04BAB1 – 435302.90 1122810.60 4,783.00 08-21-1989 161.27 4,621.73

435308112454101 07N 31E 33DCD1 ANP 5 435308.18 1124541.41 4,872.18 05-19-1989 285.96 4,586.22

435310112320901 07N 33E 35DDD1 – 435306.00 1123216.00 4,782.00 03-16-1989 99.86 4,682.14

435313112274101 07N 34E 33DCD1 – 435307.00 1122744.00 4,782.21 04-10-1989 43.58 4,738.63

435320112165301 07N 35E 36DAC1 – 435320.00 1121653.00 4,790.00 04-11-1989 65.10 4,724.90

435339112444601 07N 31E 34BDD1 USGS 25 435338.49 1124446.01 4,848.47 04-15-1989 262.09 4,586.38

435347112165301 07N 35E 36AAC1 – 435347.00 1121653.00 4,790.00 04-11-1989 37.04 4,752.96

435347112173301 07N 35E 36BBD1 – 435347.00 1121733.00 4,790.00 04-13-1989 9.61 4,780.39

435352112161701 07N 36E 31BBA1 – 435352.00 1121617.00 4,790.00 04-20-1989 37.59 4,752.41

435352112171601 07N 35E 36BAA1 – 435352.00 1121716.00 4,790.00 04-13-1989 9.30 4,780.70

435357112150201 07N 36E 32BAB1 – 435357.00 1121502.00 4,791.00 04-20-1989 14.33 4,776.67

435358112161102 07N 36E 31BAB2 – 435358.00 1121611.00 4,793.00 04-20-1989 28.28 4,764.72

435359112182501 07N 35E 26CDD1 – 435359.00 1121825.00 4,790.00 04-13-1989 7.13 4,782.87

435400112174101 07N 35E 25CCC1 – 435400.00 1121741.00 4,790.00 04-12-1989 10.67 4,779.33

435403112170501 07N 35E 25DCC1 – 435403.00 1121705.00 4,790.00 04-11-1989 8.82 4,781.18

435405112174304 07N 35E 25CCB4 – 435405.00 1121743.00 4,795.00 04-13-1989 9.66 4,785.34

435407112170904 07N 35E 25DCB4 – 435407.00 1121709.00 4,790.00 04-11-1989 6.92 4,783.08

435408112170805 07N 35E 25DCB5 – 435408.00 1121708.00 4,790.00 04-11-1989 6.60 4,783.40

435408112171202 07N 35E 25DCB2 – 435408.00 1121712.00 4,790.00 04-11-1989 6.77 4,783.23

435408112184201 07N 35E 26CDB1 – 435408.00 1121842.00 4,785.00 04-14-1989 4.89 4,780.11

435409112174303 07N 35E 25CCB3 – 435409.00 1121743.00 4,795.00 04-13-1989 10.55 4,784.45

435410112170903 07N 35E 25DCB3 – 435410.00 1121709.00 4,790.00 04-11-1989 6.74 4,783.26

435410112171403 07N 35E 25CDA3 – 435410.00 1121714.00 4,790.00 04-11-1989 7.47 4,782.53

435410112174801 07N 35E 25CCB1 – 435410.00 1121748.00 4,795.00 04-12-1989 9.47 4,785.53

435411112171001 07N 35E 25DCB1 – 435411.00 1121710.00 4,790.00 04-13-1989 6.55 4,783.45

435411112175101 07N 35E 26DDA1 – 435411.00 1121751.00 4,790.00 04-12-1989 9.93 4,780.07

435411112175801 07N 35E 26DDB1 – 435411.00 1121758.00 4,792.00 04-12-1989 12.39 4,779.61

435411112180101 07N 35E 26DAC1 – 435411.00 1121801.00 4,790.00 04-12-1989 9.30 4,780.70

435412112174701 07N 35E 25CBC1 – 435412.00 1121747.00 4,800.00 04-12-1989 18.31 4,781.69

435416112460401 07N 31E 28CAC1 P&W 1 435415.86 1124603.56 4,895.62 05-19-1989 309.14 4,586.48

435418112175601 07N 35E 26DAA1 – 435418.00 1121756.00 4,795.00 04-13-1989 11.80 4,783.20

435419112453101 07N 31E 28DAB1 P&W 2 435419.00 1124530.80 4,890.86 04-18-1989 304.65 4,586.21

435420112184801 07N 35E 26CBA1 – 435420.00 1121848.00 4,790.00 04-14-1989 5.92 4,784.08

435422112190401 07N 35E 27DAA1 – 435422.00 1121904.00 4,790.00 04-14-1989 6.41 4,783.59

435425112180301 07N 35E 26ADC1 – 435425.00 1121803.00 4,795.00 04-13-1989 9.68 4,785.32

435431112190201 07N 35E 27ADD1 – 435431.00 1121902.00 4,790.00 04-15-1989 6.99 4,783.01

435433112191001 07N 35E 27ADB1 – 435433.00 1121910.00 4,786.00 04-15-1989 4.57 4,781.43

435440112175701 07N 35E 26AAC1 – 435440.00 1121757.00 4,791.00 04-13-1989 8.01 4,782.99

435440112192002 07N 35E 27ABD2 – 435440.00 1121920.00 4,790.00 04-15-1989 7.79 4,782.21

435441112191901 07N 35E 27ABD1 – 435441.00 1121919.00 4,790.00 04-15-1989 7.49 4,782.51

435443112435801 07N 31E 26BBC1 P&W 3 435443.18 1124358.17 4,885.49 05-19-1989 298.70 4,586.79

435444112171001 07N 35E 25ABB1 – 435444.00 1121710.00 4,788.00 04-12-1989 6.88 4,781.12

435445112174501 07N 35E 25BBB1 – 435445.00 1121745.00 4,790.00 04-13-1989 6.47 4,783.53

435446112173501 07N 35E 25BBA1 – 435446.00 1121735.00 4,795.00 04-13-1989 7.31 4,787.69

435450112193601 07N 35E 27ABB1 – 435450.00 1121936.00 4,792.00 04-15-1989 7.56 4,784.44

435454112185501 07N 35E 23CCC1 – 435454.00 1121855.00 4,790.00 04-14-1989 10.32 4,779.68

435458112151301 07N 36E 20CCA1 – 435458.00 1121513.00 4,785.00 04-19-1989 0.64 4,784.36

435459112212901 07N 35E 20DDA1 – 435500.00 1122132.00 4,798.77 04-14-1989 19.84 4,778.93

435500112212502 07N 35E 20DDA2 – 435500.50 1122132.50 4,790.00 04-14-1989 10.49 4,779.51

435504112222301 07N 35E 20CBD1 – 435505.00 1122222.00 4,818.15 04-15-1989 35.71 4,782.44

435505112190201 07N 35E 22DAD1 – 435505.00 1121902.00 4,792.49 04-15-1989 8.16 4,784.33
Appendix 1 185

Table 1-1. Water-level measurements used to construct water-table contours, Idaho National Laboratory and vicinity, eastern 

Idaho.—Continued

USGS site 

No.

USGS station 

No.

Site 

name

Latitude 

(NAD 27)

Longitude 

(NAD 27)

Altitude

(ft)

Water-level 

measurement 

date

Water 

level

(ft bls)

Waterlevel 

altitude

(ft)

435505112200001 07N 35E 22CBD1 – 435505.00 1122000.00 4,790.00 04-17-1989 8.40 4,781.60

435505112200002 07N 35E 22CBD2 – 435505.00 1122000.00 4,790.00 04-17-1989 8.76 4,781.24

435506112185301 07N 35E 23CBC1 – 435506.00 1121853.00 4,790.00 04-14-1989 9.03 4,780.97

435506112191701 07N 35E 22DAC1 – 435506.00 1121903.00 4,790.00 04-15-1989 9.67 4,780.33

435522112444201 07N 31E 22BDD1 ANP 7 435519.50 1124443.67 4,934.64 05-19-1989 346.86 4,587.78

435529112232501 07N 35E 19BDB1 – 435529.00 1122325.00 4,791.00 04-11-1989 8.21 4,782.79

435529112233601 07N 35E 19BCA1 – 435529.00 1122336.00 4,793.00 04-11-1989 8.39 4,784.61

435533112244801 07N 34E 24BBC1 – 435533.00 1122448.00 4,795.00 04-12-1989 12.08 4,782.92

435535112235801 07N 34E 24AAC1 – 435535.00 1122358.00 4,792.61 04-11-1989 8.73 4,783.88

435537112231901 07N 35E 19BAA1 – 435537.00 1122319.00 4,810.00 04-11-1989 13.00 4,797.00

435539112244101 07N 34E 24BBA2 – 435539.00 1122441.00 4,790.00 04-15-1989 10.40 4,779.60

435541112240301 07N 34E 24ABA1 – 435541.00 1122403.00 4,792.00 04-11-1989 7.26 4,784.74

435541112254303 07N 34E 23BAB3 – 435541.00 1122547.00 4,791.83 04-12-1989 9.20 4,782.63

435543112174401 07N 35E 13CCC2 – 435543.00 1121744.00 4,793.72 04-18-1989 11.94 4,781.78

435543112320401 07N 33E 14DDC1 – 435543.00 1123225.00 4,783.00 04-16-1989 70.32 4,712.68

435544112173001 07N 35E 13CDC1 – 435544.00 1121730.00 4,800.00 04-17-1989 13.42 4,786.58

435544112174303 07N 35E 13CCC3 – 435544.00 1121743.00 4,795.00 04-18-1989 11.25 4,783.75

435544112234001 07N 35E 18CCD1 – 435544.00 1122340.00 4,798.00 04-12-1989 11.13 4,786.87

435547112173701 07N 35E 13CCD1 – 435547.00 1121737.00 4,792.29 04-18-1989 12.25 4,780.04

435548112173503 07N 35E 13CCD3 – 435548.00 1121735.00 4,800.00 04-17-1989 14.86 4,785.14

435548112233901 07N 35E 18CDC1 – 435548.00 1122339.00 4,809.00 04-12-1989 24.71 4,784.29

435551112313301 07N 33E 13CDA1 – 435550.00 1123135.70 4,783.00 04-19-1989 25.94 4,757.06

435553112240201 07N 34E 13DCA1 – 435553.00 1122402.00 4,795.00 04-11-1989 8.91 4,786.09

435604112240501 07N 34E 13DBA1 – 435604.00 1122405.00 4,799.00 04-11-1989 9.75 4,789.25

435610112241501 07N 34E 13ACC1 – 435610.00 1122418.00 4,799.61 04-11-1989 16.92 4,782.69

435626112164301 07N 35E 13AAD1 – 435626.00 1121643.00 4,789.50 04-19-1989 5.24 4,784.26

435626112365401 07N 33E 17BBC1 ML 2 435626.00 1123654.00 4,791.00 04-17-1989 207.26 4,583.74

435634112263201 07N 34E 15ABA1 – 435634.00 1122632.00 4,815.00 04-10-1989 32.56 4,782.44

435640112265601 07N 34E 10CDC1 – 435640.00 1122656.00 4,795.00 04-11-1989 13.69 4,781.31

435644112315901 07N 33E 12CCB1 – 435644.00 1123159.00 4,790.02 04-16-1989 38.42 4,751.60

435645112311301 07N 33E 12DDB1 – 435645.00 1123113.00 4,784.00 04-16-1989 34.64 4,749.36

435647112263401 07N 34E 10DCB1 – 435647.00 1122634.00 4,829.00 04-10-1989 44.42 4,784.58

435652112362701 07N 33E 08CAD1 – 435652.00 1123627.00 4,792.00 04-17-1989 202.07 4,589.93

435707112270701 07N 34E 10BCA1 – 435707.00 1122707.00 4,795.00 04-12-1989 6.91 4,788.09

435712112263201 07N 34E 10ACA1 – 435712.90 1122636.30 4,805.00 04-10-1989 17.43 4,787.57

435716112273601 07N 34E 09ABD1 – 435716.00 1122736.00 4,792.00 04-12-1989 7.22 4,784.78

435716112365701 07N 33E 07AAD1 – 435716.00 1123657.00 4,791.00 04-17-1989 202.46 4,588.54

435720112255101 07N 34E 11BBD1 – 435720.00 1122556.00 4,856.00 04-10-1989 71.35 4,784.65

435726112274401 07N 34E 04DCD1 – 435726.00 1122744.00 4,794.00 04-14-1989 10.02 4,783.98

435727112354501 07N 33E 05DDD1 – 435727.00 1123545.00 4,792.00 04-18-1989 116.95 4,675.05

435728112281101 07N 34E 04CDC1 – 435728.00 1122809.00 4,791.76 04-14-1989 7.98 4,783.78

435728112303601 07N 34E 06CDC1 – 435728.00 1123036.00 4,791.00 04-18-1989 14.16 4,776.84

435731112272801 07N 34E 04DDD1 – 435731.00 1122728.00 4,794.00 04-14-1989 7.63 4,786.37

435735112264701 07N 34E 03CDA1 – 435736.00 1122651.00 4,798.00 04-13-1989 13.78 4,784.22

435744112152801 07N 36E 06DAD1 – 435744.00 1121528.00 4,800.00 04-19-1989 11.13 4,788.87

435744112324201 07N 33E 02DBC1 – 435744.00 1123245.00 4,789.00 04-18-1989 52.18 4,736.82

435745112273901 07N 34E 04DAD1 – 435745.00 1122739.00 4,794.00 04-13-1989 8.24 4,785.76

435745112284601 07N 34E 05DAC1 – 435745.00 1122846.00 4,790.00 04-14-1989 6.30 4,783.70

435747112155001 07N 36E 06DBA1 – 435747.00 1121550.00 4,800.00 04-19-1989 8.15 4,791.85

435749112164001 07N 35E 01DAA1 – 435749.00 1121640.00 4,794.90 04-18-1989 10.09 4,784.81

435751112332401 07N 33E 03DAA1 – 435751.00 1123324.00 4,789.00 04-18-1989 24.10 4,764.90

435752112371501 07N 33E 06DBA1 – 435752.00 1123715.00 4,800.00 04-17-1989 209.46 4,590.54
186 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 1-1. Water-level measurements used to construct water-table contours, Idaho National Laboratory and vicinity, eastern 

Idaho.—Continued

USGS site 

No.

USGS station 

No.

Site 

name

Latitude 

(NAD 27)

Longitude 

(NAD 27)

Altitude

(ft)

Water-level 

measurement 

date

Water 

level

(ft bls)

Waterlevel 

altitude

(ft)

435754112363601 07N 33E 05BDC1 – 435754.00 1123636.00 4,794.00 04-17-1989 203.15 4,590.85

435755112231001 07N 35E 06ACC1 – 435755.00 1122310.00 4,857.00 04-15-1989 73.36 4,783.64

435756112263301 07N 34E 03ACD1 – 435756.00 1122633.00 4,811.00 04-13-1989 25.02 4,785.98

435756112264601 07N 34E 03BDD1 – 435757.00 1122651.00 4,798.00 04-13-1989 12.26 4,785.74

435759112164801 07N 35E 01ADC1 – 435759.00 1121648.00 4,798.00 04-19-1989 7.28 4,790.72

435803112162101 07N 36E 06BCA1 – 435803.00 1121623.00 4,798.22 04-20-1989 8.57 4,789.65

435805112270501 07N 34E 03BCA1 – 435805.00 1122705.00 4,800.00 04-13-1989 16.74 4,783.26

435806112265501 07N 34E 03BAC1 – 435806.00 1122655.00 4,800.00 04-13-1989 14.05 4,785.95

435809112320901 07N 33E 02AAD1 – 435809.00 1123209.00 4,789.00 04-19-1989 39.21 4,749.79

435810112264901 07N 34E 03BAD1 – 435810.00 1122649.00 4,800.00 04-13-1989 14.88 4,785.12

435810112365401 07N 33E 05BBC1 ML 3 435810.00 1123654.00 4,795.00 04-17-1989 204.42 4,590.58

435812112264301 07N 34E 03BAA1 – 435812.00 1122643.00 4,798.00 04-13-1989 17.00 4,781.00

435814112241301 07N 34E 01ABB1 – 435814.00 1122413.00 4,870.00 04-15-1989 85.18 4,784.82

435817112365401 07N 33E 05BBB1 – 435817.00 1123657.00 4,796.00 06-23-1989 207.92 4,588.08

435820112343501 08N 33E 33DDD1 – 435820.00 1123438.00 4,790.00 06-23-1989 81.85 4,708.15

435825112161801 08N 36E 31CDB1 – 435825.00 1121618.00 4,800.00 04-18-1989 13.86 4,786.14

435828112153101 08N 36E 31DDA1 – 435828.00 1121531.00 4,800.00 04-20-1989 11.10 4,788.90

435831112365401 08N 33E 32CCB1 – 435831.20 1123658.20 4,801.00 04-17-1989 210.76 4,590.24

435842112303601 08N 34E 31CAB1 – 435842.00 1123036.00 4,793.00 04-19-1989 11.13 4,781.87

435844112354301 08N 33E 33CBB1 – 435844.00 1123543.00 4,791.00 04-18-1989 195.50 4,595.50

435857112365501 08N 33E 32BCB1 – 435857.00 1123655.00 4,804.00 04-17-1989 214.47 4,589.53

435900112302801 08N 34E 31BAD1 – 435900.00 1123028.00 4,794.00 04-19-1989 10.42 4,783.58

435903112280001 08N 34E 33BAD1 – 435903.00 1122800.00 4,803.75 04-18-1989 17.53 4,786.22

435910112261801 08N 34E 34AAB1 – 435910.00 1122618.00 4,820.00 04-15-1989 24.85 4,795.15

435910112361901 08N 33E 32ABB1 – 435910.00 1123619.00 4,794.00 04-17-1989 203.97 4,590.03

435912112264801 08N 34E 27CDD1 – 435912.00 1122648.00 4,805.00 04-16-1989 29.99 4,775.01

435913112271601 08N 34E 27CCC1 – 435913.00 1122716.00 4,810.00 08-23-1989 40.13 4,769.87

435913112281501 08N 34E 28CCD1 – 435913.00 1122815.00 4,810.00 08-23-1989 40.95 4,769.05

435914112261301 08N 34E 27DDD1 – 435914.00 1122613.00 4,800.00 04-15-1989 24.41 4,775.59

435917112255801 08N 34E 26CCC1 – 435917.00 1122558.00 4,820.00 08-23-1989 46.75 4,773.25

435919112260201 08N 34E 26CCB1 – 435919.00 1122606.00 4,813.94 04-15-1989 27.50 4,786.44

435922112272401 08N 34E 28DDA1 – 435922.00 1122724.00 4,805.00 04-18-1989 25.19 4,779.81

435925112281401 08N 34E 28CBD1 – 435925.00 1122814.00 4,805.00 04-18-1989 18.57 4,786.43

435925112333601 08N 33E 27DAC1 – 435924.00 1123340.00 4,793.00 06-23-1989 14.79 4,778.21

435927112324401 08N 33E 26CAD1 – 435927.00 1123244.00 4,793.00 04-19-1989 8.98 4,784.02

435931112262701 08N 34E 27DBA1 – 435931.00 1122627.00 4,811.00 08-23-1989 42.67 4,768.33

435935112255401 08N 34E 26CBA1 – 435935.00 1122554.00 4,822.00 08-23-1989 50.23 4,771.77

435935112325401 08N 33E 26CAB2 – 435935.00 1123254.00 4,800.00 04-19-1989 9.83 4,790.17

435950112332304 08N 33E 27AAD4 – 435950.00 1123323.00 4,794.00 04-19-1989 15.51 4,778.49

435951112275101 08N 34E 28ABC1 – 435951.00 1122751.00 4,806.00 04-18-1989 18.54 4,787.46

435952112332102 08N 33E 27AAD2 – 435952.00 1123321.00 4,794.00 04-19-1989 47.65 4,746.35

435958112290602 08N 34E 29ABB2 – 435958.00 1122906.00 4,815.00 04-18-1989 29.72 4,785.28

440012112291401 08N 34E 20CDA2 – 440012.00 1122914.00 4,818.94 04-16-1989 37.93 4,781.01

440014112343001 08N 33E 22CCB1 – 440014.00 1123430.00 4,800.00 04-19-1989 174.59 4,625.41

440019112320301 08N 33E 24CBC1 – 440019.00 1123203.00 4,794.00 04-17-1989 7.50 4,786.50

440022112284601 08N 34E 20DAC1 – 440022.00 1122846.00 4,808.00 04-17-1989 27.72 4,780.28

440024112252501 08N 34E 23DBB1 – 440024.00 1122525.00 4,837.00 04-18-1989 40.61 4,796.39

440025112272701 08N 34E 21DAA1 – 440025.00 1122727.00 4,820.00 04-18-1989 19.65 4,800.35

440029112352601 08N 33E 21CAB1 – 440029.00 1123526.00 4,800.00 04-18-1989 174.09 4,625.91

440030112261801 08N 34E 22ADC1 – 440030.00 1122618.00 4,830.00 04-18-1989 40.37 4,789.63

440043112275001 08N 34E 21ABC1 – 440043.00 1122750.00 4,825.00 04-17-1989 38.75 4,786.25

440045112283501 08N 34E 20AAD1 – 440044.10 1122837.70 4,810.00 04-17-1989 25.13 4,784.87
Appendix 1 187

Table 1-1. Water-level measurements used to construct water-table contours, Idaho National Laboratory and vicinity, eastern 

Idaho.—Continued

USGS site 

No.

USGS station 

No.

Site 

name

Latitude 

(NAD 27)

Longitude 

(NAD 27)

Altitude

(ft)

Water-level 

measurement 

date

Water 

level

(ft bls)

Waterlevel 

altitude

(ft)

440052112314901 08N 33E 24BAB1 – 440052.00 1123149.00 4,797.00 04-17-1989 7.71 4,789.29

440054112260801 08N 34E 22AAA1 – 440054.00 1122608.00 4,824.74 04-18-1989 39.55 4,785.19

440106112263101 08N 34E 15DCA1 – 440106.00 1122634.00 4,822.45 04-18-1989 35.52 4,786.93

440108112335701 08N 33E 15CAD1 – 440108.00 1123357.00 4,804.90 04-18-1989 59.37 4,745.53

440108112350901 08N 33E 16CAD1 – 440108.00 1123509.00 4,806.00 04-18-1989 131.98 4,674.02

440109112391301 08N 32E 13CBC1 – 440109.00 1123913.00 4,880.00 04-17-1989 292.51 4,587.49

440118112262001 08N 34E 15DAB1 – 440118.00 1122620.00 4,828.00 04-18-1989 39.23 4,788.77

440123112280101 08N 34E 16BDD1 – 440123.00 1122801.00 4,810.00 04-17-1989 23.89 4,786.11

440134112350901 08N 33E 16ACB1 – 440134.00 1123509.00 4,811.00 04-18-1989 132.30 4,678.70

440142112302001 08N 34E 18BAA1 – 440142.00 1123020.00 4,803.00 04-17-1989 14.45 4,788.55

440143112330501 08N 33E 14BBA1 – 440143.00 1123305.00 4,807.00 04-17-1989 57.09 4,749.91

440150112351001 08N 33E 09CDD1 – 440150.00 1123510.00 4,816.00 04-18-1989 123.16 4,692.84

440151112252301 08N 34E 11DCC1 – 440151.00 1122523.00 4,870.00 04-18-1989 82.60 4,787.40

440155112272901 08N 34E 09DDB1 – 440155.00 1122729.00 4,830.00 04-17-1989 39.78 4,790.22

440159112335701 08N 33E 10CDA1 – 440159.00 1123357.00 4,816.00 04-18-1989 69.81 4,746.19

440220112381201 08N 32E 12ADB1 – 440220.00 1123812.00 4,848.00 04-17-1989 257.33 4,590.67

440225112332101 08N 33E 10ADA1 – 440225.00 1123321.00 4,815.00 04-19-1989 64.06 4,750.94

440226112402401 08N 32E 11BCB1 – 440224.00 1124026.00 4,950.00 04-17-1989 444.00 4,506.00

440237112295201 08N 34E 07AAA1 – 440237.00 1122952.00 4,810.00 04-19-1989 21.44 4,788.56

440240112330201 08N 33E 02CDC1 – 440240.00 1123302.00 4,812.00 04-19-1989 63.65 4,748.35

440252112352401 08N 33E 04CDB1 – 440252.00 1123524.00 4,827.00 04-15-1989 227.78 4,599.22

440303112322001 08N 33E 02DAB1 – 440303.00 1123220.00 4,813.00 04-19-1989 77.24 4,735.76

440321112353401 08N 33E 04BBC1 – 440321.00 1123534.00 4,849.00 04-15-1989 248.64 4,600.36

440322112320301 08N 33E 01BBC1 – 440322.00 1123203.00 4,821.00 04-19-1989 38.52 4,782.48

440328112314501 08N 33E 01BAB1 – 440328.00 1123145.00 4,817.00 04-10-1989 64.44 4,752.56

440328112335101 08N 33E 03ABB1 – 440328.00 1123351.00 4,835.00 04-10-1989 188.77 4,646.23

440329112293001 08N 34E 05BBA1 – 440329.00 1122930.00 4,816.00 04-19-1989 33.76 4,782.24

440329112353801 08N 33E 04BBB1 – 440329.00 1123538.00 4,850.00 04-11-1989 255.50 4,594.50

440333112301201 09N 34E 31DCC1 – 440333.00 1123012.00 4,816.00 04-15-1989 47.44 4,768.56

440343112332101 09N 33E 34DAD1 – 440343.00 1123323.00 4,840.00 04-10-1989 147.72 4,692.28

440347112313001 09N 33E 36CAD1 – 440347.00 1123130.00 4,817.00 04-10-1989 44.31 4,772.69

440348112354601 09N 33E 32DAD1 – 440348.00 1123546.00 4,880.00 04-10-1989 259.60 4,620.40

440351112372701 09N 33E 31DBB1 – 440351.00 1123727.00 4,902.00 04-11-1989 301.56 4,600.44

440355112291901 09N 34E 32BDC1 – 440355.00 1122919.00 4,826.00 04-19-1989 47.40 4,778.60

440355112343101 09N 33E 33DAA1 – 440355.00 1123431.00 4,866.00 04-10-1989 220.80 4,645.20

440357112385901 09N 32E 36CCB1 – 440343.00 1123921.00 4,940.00 04-17-1989 347.93 4,592.07

440405112151101 09N 36E 32BCB1 – 440405.00 1121511.00 4,879.00 04-13-1989 87.39 4,791.61

440408112361601 09N 33E 32ACB1 – 440408.00 1123616.00 4,915.00 04-11-1989 303.00 4,612.00

440409112155801 09N 36E 31BAD1 – 440409.00 1121558.00 4,919.00 09-01-1989 129.97 4,789.03

440409112313001 09N 33E 36ACB1 – 440409.00 1123130.00 4,823.00 04-19-1989 62.26 4,760.74

440409112343501 09N 33E 33AAD1 – 440409.00 1123435.00 4,880.00 04-10-1989 263.25 4,616.75

440416112294002 09N 34E 32BBB2 – 440416.00 1122940.00 4,827.00 04-19-1989 50.66 4,776.34

440420112303801 09N 34E 31BBA1 – 440420.00 1123038.00 4,823.00 04-10-1989 60.18 4,762.82

440420112314601 09N 33E 36BAB1 – 440420.00 1123146.00 4,834.00 04-11-1989 77.71 4,756.29

440421112305501 09N 33E 36AAA1 – 440421.00 1123055.00 4,824.00 04-10-1989 58.68 4,765.32

440428112282801 09N 34E 28CCB1 – 440428.00 1122828.00 4,835.00 04-19-1989 52.25 4,782.75

440434112305401 09N 33E 25DDA1 – 440434.00 1123054.00 4,827.00 04-11-1989 64.90 4,762.10

440434112312701 09N 33E 25DCB1 – 440434.00 1123127.00 4,831.00 04-11-1989 75.53 4,755.47

440438112151001 09N 36E 29CBC1 – 440438.00 1121510.00 4,887.00 04-13-1989 86.90 4,800.10

440447112280301 09N 34E 28CAB1 – 440447.00 1122803.00 4,839.00 04-19-1989 57.33 4,781.67

440447112284401 09N 34E 29DAB1 – 440447.00 1122845.00 4,838.00 04-19-1989 56.96 4,781.04

440447112292201 09N 34E 29CAB1 – 440447.00 1122922.00 4,837.00 04-19-1989 58.15 4,778.85
188 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Table 1-1. Water-level measurements used to construct water-table contours, Idaho National Laboratory and vicinity, eastern 

Idaho.—Continued

USGS site 

No.

USGS station 

No.

Site 

name

Latitude 

(NAD 27)

Longitude 

(NAD 27)

Altitude

(ft)

Water-level 

measurement 

date

Water 

level

(ft bls)

Waterlevel 

altitude

(ft)

440447112303701 09N 34E 30CBA1 – 440447.00 1123037.00 4,829.00 04-11-1989 67.63 4,761.37

440448112283801 09N 34E 29DAA1 – 440448.00 1122838.00 4,839.00 03-29-1989 57.82 4,781.18

440451112154601 09N 36E 30ACC1 – 440447.10 1121548.90 4,900.00 04-13-1989 106.10 4,793.90

440457112265201 09N 34E 27BDB1 – 440458.00 1122654.00 4,853.00 04-19-1989 65.26 4,787.74

440458112325701 09N 33E 26BDB1 – 440458.00 1123257.00 4,885.00 04-12-1989 206.20 4,678.80

440500112313001 09N 33E 25ACB1 – 440500.00 1123130.00 4,845.00 04-11-1989 89.93 4,755.07

440514112300001 09N 34E 30ABA1 – 440514.00 1123000.00 4,839.00 04-19-1989 65.14 4,773.86

440514112303501 09N 34E 30BBA1 – 440514.00 1123038.00 4,837.00 04-11-1989 70.34 4,766.66

440515112284701 09N 34E 20DCD1 – 440515.00 1122847.00 4,845.00 04-19-1989 65.19 4,779.81

440523112154501 09N 36E 19DCB1 – 440523.00 1121545.00 4,907.00 04-13-1989 114.15 4,792.85

440525112314601 09N 33E 24CDB1 – 440525.00 1123146.00 4,868.00 04-12-1989 123.39 4,744.61

440537112295401 09N 34E 19DAB1 – 440537.00 1122954.00 4,845.00 04-19-1989 72.13 4,772.87

440539112281201 09N 34E 21BCD1 – 440539.00 1122812.00 4,857.00 04-19-1989 72.38 4,784.62

440541112303501 09N 34E 19CAB1 – 440541.00 1123035.00 4,846.00 04-11-1989 86.28 4,759.72

440553112162401 09N 36E 19BBC1 – 440553.00 1121624.00 4,921.00 04-13-1989 128.28 4,792.72

440553112170001 09N 35E 24ABC1 – 440551.50 1121703.90 4,921.00 04-13-1989 129.09 4,791.91

440554112154501 09N 36E 19ABC1 – 440554.00 1121545.00 4,924.00 04-13-1989 131.84 4,792.16

440557112361401 09N 33E 20ACC1 – 440545.00 1123612.00 5,091.00 04-13-1989 433.62 4,657.38

440600112261601 09N 34E 15DDC1 – 440606.00 1122606.00 4,870.00 08-23-1989 90.02 4,779.98

440605112313201 09N 33E 24BAA1 – 440605.00 1123133.00 4,878.00 04-12-1989 175.40 4,702.60

440606112303601 09N 34E 18CCD1 – 440606.00 1123036.00 4,852.00 04-11-1989 90.45 4,761.55

440619112172301 09N 35E 13CBD1 – 440619.00 1121723.00 4,926.00 04-14-1989 133.37 4,792.63

440619112330001 09N 33E 14CCA1 – 440619.00 1123300.00 4,990.00 08-24-1989 287.89 4,702.11

440620112164101 09N 35E 13DAC1 – 440620.00 1121641.00 4,929.00 04-14-1989 136.90 4,792.10

440626112154501 09N 36E 18DBB1 – 440626.00 1121545.00 4,942.00 04-13-1989 147.14 4,794.86

440631112301901 09N 34E 18CAA1 – 440631.00 1123019.00 4,855.00 04-12-1989 98.77 4,756.23

440633112261801 09N 34E 15ADC1 – 440633.00 1122618.00 4,885.00 08-23-1989 84.37 4,800.63

440633112280901 09N 34E 16BCD1 – 440633.00 1122809.00 4,873.00 04-20-1989 89.25 4,783.75

440633112284801 09N 34E 17ACD1 – 440633.00 1122848.00 4,867.00 04-20-1989 85.37 4,781.63

440633112292101 09N 34E 17BDC1 – 440633.00 1122921.00 4,862.00 04-20-1989 93.85 4,768.15

440634112265801 09N 34E 15BCD1 – 440634.00 1122658.00 4,885.00 04-20-1989 95.10 4,789.90

440634112273301 09N 34E 16ADC1 – 440634.00 1122733.00 4,880.00 04-20-1989 93.00 4,787.00

440637112183401 09N 35E 14BCD1 – 440637.00 1121834.00 4,928.00 04-15-1989 148.27 4,779.73

440640112150901 09N 36E 17BCB1 – 440640.00 1121509.00 4,960.00 04-12-1989 166.02 4,793.98

440645112303501 09N 34E 18BDB1 – 440645.00 1123035.00 4,855.00 04-11-1989 97.53 4,757.47

440645112333701 09N 33E 15ACA1 – 440645.00 1123337.00 5,040.00 04-14-1989 337.16 4,702.84

440655112313301 09N 33E 13BAA1 – 440656.00 1123135.00 4,893.00 04-12-1989 173.63 4,719.37

440657112154501 09N 36E 18ABA1 – 440657.00 1121545.00 4,955.00 04-13-1989 161.02 4,793.98

440659112190601 09N 35E 10DDC1 – 440659.00 1121906.00 4,945.00 04-11-1989 153.38 4,791.62

440710112150901 09N 36E 08CCB1 – 440710.00 1121509.00 4,970.00 04-12-1989 179.40 4,790.60

440710112300101 09N 34E 07DCA1 – 440710.00 1123001.00 4,868.00 04-12-1989 94.50 4,773.50

440714112303401 09N 34E 07CCA1 – 440711.00 1123035.00 4,864.00 04-12-1989 92.80 4,771.20

440720112262001 09N 34E 10DAB1 – 440720.00 1122620.00 4,903.00 04-14-1989 149.32 4,753.68

440721112272901 09N 34E 09DAB1 – 440721.00 1122729.00 4,893.00 04-14-1989 123.41 4,769.59

440722112260301 09N 34E 10DAA1 – 440722.00 1122603.00 4,914.00 04-14-1989 136.09 4,777.91

440725112245301 09N 34E 11ADD1 – 440725.00 1122453.00 4,945.00 04-20-1989 156.23 4,788.77

440734112205401 09N 35E 09BDB1 – 440736.50 1122059.20 4,973.00 04-10-1989 183.34 4,789.66

440737112301701 09N 34E O7ABC1 – 440737.00 1123017.00 4,875.00 04-11-1989 111.38 4,763.62

440737112314501 09N 33E 12BAC1 – 440732.00 1123148.00 4,898.00 04-13-1989 180.53 4,717.47

440805112250801 09N 34E 02DAC1 – 440805.00 1122508.00 4,945.00 04-14-1989 154.20 4,790.80

440813112270101 09N 34E 03CBA1 – 440813.00 1122701.00 4,920.00 04-13-1989 144.00 4,776.00

440814112292401 09N 34E 05CBA1 – 440814.00 1122924.00 4,892.00 04-13-1989 129.03 4,762.97
Appendix 1 189

Table 1-1. Water-level measurements used to construct water-table contours, Idaho National Laboratory and vicinity, eastern 

Idaho.—Continued

USGS site 

No.

USGS station 

No.

Site 

name

Latitude 

(NAD 27)

Longitude 

(NAD 27)

Altitude

(ft)

Water-level 

measurement 

date

Water 

level

(ft bls)

Waterlevel 

altitude

(ft)

440815112254601 09N 34E 02CBA1 – 440815.00 1122546.00 4,938.00 04-13-1989 155.50 4,782.50

440815112261901 09N 34E 03DAB1 – 440815.00 1122619.00 4,931.00 04-13-1989 148.28 4,782.72

440815112284501 09N 34E 05DAB1 – 440815.00 1122845.00 4,901.00 04-13-1989 131.25 4,769.75

440815112295801 09N 34E 06ADC1 – 440815.00 1122958.00 4,890.00 04-13-1989 130.18 4,759.82

440816112280901 09N 34E 04BDC1 – 440816.00 1122809.00 4,910.00 04-13-1989 134.00 4,776.00

440816112303201 09N 34E 06CAB1 – 440816.00 1123032.00 4,885.00 04-13-1989 150.77 4,734.23

440817112201601 09N 35E 04ADC1 – 440817.00 1122016.00 4,988.00 04-10-1989 195.25 4,792.75

440817112213501 09N 35E 05ACD1 – 440817.00 1122135.00 4,992.00 04-10-1989 202.71 4,789.29

440817112273501 09N 34E 04ACD1 – 440816.00 1122737.00 4,915.00 04-13-1989 143.20 4,771.80

440847112303501 10N 34E 31CCD1 – 440847.00 1123035.00 4,917.00 04-14-1989 178.80 4,738.20

440908112213501 10N 35E 32DBA1 – 440907.60 1122135.00 5,030.00 04-10-1989 240.16 4,789.84

441003112290801 10N 34E 29BDD1 – 440957.00 1122907.00 5,030.00 03-29-1989 258.68 4,771.32

441014112284501 10N 34E 29AAC1 – 441014.00 1122845.00 4,990.00 04-14-1989 225.68 4,764.32

441132112173301 10N 35E 13CBC1 – 441133.00 1121737.00 5,150.96 04-10-1989 356.89 4,794.07
190 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho
Appendix 2 191

Alkalinity

For alkalinity titrations to the methyl-orange end point, 

alkalinity expressed as milligrams per liter as calcium 

carbonate (CaCO3) can be converted to an equivalent 

concentration of bicarbonate in milligrams per liter with the 

following equation (Hem, 1992):

 Alkalinity / . 0 8202 = Bicarbonate. (2–1)

Delta Notation

The isotope ratios of helium (3He/4He), hydrogen (2H/1H), 

oxygen (18O/16O), carbon (13C/12C), sulfur (34S/32S), and 

nitrogen (15N/14N) were reported as a percentage or permil 

using delta notation (δ), which is the ratio of the abundance of 

the minor isotope to the predominant isotope for an element in 

a sample relative to the same isotopes in a reference material. 

For example, for the oxygen stable isotope ratio the delta 

notation is:

 δ

18

18 16 18 16

18 16

O

O O O O

O O sample

sample reference

refe

=

( ) − ( )

( )

/ /

/ rence

× M, (2–2)

where

 18 16 O O sample ( ) / is the isotope ratio of oxygen-18 and 

 oxygen-16 of the sample,

18 16 O O

reference ( ) / is the isotope ratio of oxygen-18 and

 oxygen-16 of the reference material,

 and

 M is a multiplication factor of 100 or 1,000

 to express reported δ-values as parts per

 hundred (percent) or parts per thousand

 (permil), respectively. 

Delta notations are δ3He for helium, δ2H for hydrogen, δ13C 

for carbon, δ34S for sulfur and δ15N for nitrogen.

Normalized Absolute Difference

Normalized absolute difference (NAD) is calculated as:

NAD x y

CSU C x y SU

= =

+2 2

, (2–3)

where

x is the concentration of a radiochemical in the 

environmental sample,

y is the concentration of the same radiochemical 

in the replicate sample,

CSUx is the combined standard uncertainty of x at 

the 1σ confidence level, and

CSUy is the combined standard uncertainty of y at 

the 1σ confidence level.

Relative Standard Deviation

Relative standard deviation (RSD) is the percent 

coefficient of variation (CV), and CV “is a dimensionless 

quantity that measures the amount of variability relative to the 

value of the mean” (Devore, 1995, p. 39). RSD was calculated 

as (Taylor, 1987, p. 20):

RSD C= × V 100 . (2–4)

The CV was calculated as:

CV s

x = , (2–5)

where

s is the standard deviation for a constituent 

from a replicate, and

x is the mean concentration for the same 

constituent from a replicate.

The standard deviations and mean concentrations for 

constituents from replicates were calculated as:

s

x x

n

i

n

i = −

−

∑ =1

2

1

( ) , (2–6)

and

1

n

i i

n x x = = ∑ , (2–7)

where

xi is a constituent concentration from the 

replicate, and

n is the number of measured concentrations for 

a constituent from the replicate.

Appendix 2. Equations
192 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

The degrees of freedom is an important piece of 

information for estimates of standard deviation (Taylor, 1987, 

p. 21), and is included in the equation for standard deviation 

as n –1, or the number of independent values. The degrees of 

freedom (or number of independent values) is 1 for duplicates 

because n is 2, 2 for triplicates because n is 3, and so forth.

Relative Percent Difference

 If the uncertainty of a chemical constituent is not 

readily available, which is often the case for measurements 

of inorganic and organic constituents, the relative percent 

difference (RPD) can be used to compare equivalency of 

replicate pairs (Bartholomay and others, 2015). The RPD is 

calculated as: 

 RPD = − ( ) ( ) ABS ( ) X X 1 2 /( ) X X 1 2 + ×100 , (2–8)

where 

RPD is the relative percent difference, 

ABS is the absolute value, 

X1 is the result from the environmental sample, 

and 

X2 is the result from the replicate.

Binomial Probability Distribution

A non-parametric statistical method was used to estimate 

the potential contamination bias of environmental samples 

because the distribution of constituent concentrations from 

blank samples was highly skewed. The statistical method 

consisted of order statistics (ranking concentrations for each 

constituent from small to large) and the binomial probability 

distribution (Rattray, 2014). This statistical method provided 

an upper confidence limit, or confidence level (cl), that 

represented “the probability that m observed values from a 

total of n observations are equal to or less than the 100pth 

percentile of the sample population” (Mueller, 1998, p. 5). 

The confidence level is calculated as:

 cl = Prob( ) n m, , p . (2–9)

Charge Balance

Charge balance (CB) was calculated as:

 CB

C C

C C

i

i

j

j

i

i

j

j

= −

+

× ∑ ∑

∑ ∑

1 1

1 1

100 , (2–10)

where

CB is the charge balance for a water sample,

Ci is the concentration of a cation in the water 

sample,

Cj is the concentration of an anion in the water 

sample, and

i and j are the number of measured cation and anion 

species, respectively, in the water sample.

Rs/Ra

The Rs/Ra ratio is a convenient method for evaluating the 3

He/4He ratios of environmental samples. The Rs/Ra ratio was 

calculated from δ3He values as (Plummer and others, 2000):

 δ3

He R R 1 100 = ( ) s a −  

 / × , (2–11)

where

Rs is the 3He/4He ratio of the environmental 

sample, and

Ra is the 3He/4He ratio of air = 1.384 × 10-6.

Radioactive Decay of Tritium

The equation for radioactive decay is (Faure, 1986):

 3 3 H H0e t = −λt , (2–12)

where 3

Ht is the activity of 3H in groundwater at time (t), 3

H0 is the initial (t

0

) activity of 3H in 

groundwater1,

λ is the decay constant (λ = 0.05575/year for 3

H), and

t is the time elapsed between recharge and 

sample collection.

1

Initial, or t

0

, refers to the time of recharge, and the activity of 3H in groundwater at t

0

 is assumed to be the same as the activity of 3H in precipitation at t

0

 for 

rapid recharge (rapid recharge is a far more prevalent recharge process on the ESRP at the INL than slow recharge [fig. 14]).
Appendix 2 193

Regression of Tritium Data

The monthly activity of 3H in precipitation at the INL 

for 2002 through 2012 was estimated from a regression 

(R2 = 0.91) of calculated monthly 3H activities from data 

provided by R.L. Michel (U.S. Geological Survey, written 

commun., 2012) with monthly 3H activities in precipitation 

measured at Vienna (International Atomic Energy Agency/

World Meteorological Organization, 2015) for 1990 through 

2001. The regression was performed on monthly 3H activities 

for 1990 through 2001 because these 3H activities were 

the closest representation of the expected 3H activities in 

precipitation at the INL for 2002 through 2012. The equation 

resulting from the regression was:

y m= +x b , (2–13)

where

y is the activity of 3H in precipitation at the 

INL,

m is 0.9564,

x is the activity of 3H in precipitation at Vienna, 

and

b is 9.1317.

Ingrowth of Helium-3 Produced by 

Decay of Tritium

The equation for ingrowth of 3He produced by radioactive 

decay of 3H (that is, tritiogenic 3He) is (Faure, 1986):

3 3

0 He H e 1 t

t = − ( ) −λ , (2–14)

where 3

Het is the activity of 3He in groundwater at time 

(t) produced by decay of 3H, 3

H0 is the activity of 3H in precipitation at the time 

of recharge,

λ is the decay constant (λ = 0.05575/year for 3

H), and

t is the time elapsed between recharge and 

sample collection.

Radioisotope Mixing Equation

The radioisotope mixing equation is for a mixture of two 

waters, where the chemical element of interest has different 

concentrations and isotope ratios in each water. The mixing 

equation is (Faure, 1986, eq. 9.21):

R

R C f R C f

C f C f m

x a

x

a

x

b

x

b

x

a

x

b

x = + − ( )

+ − ( )

1

1

, (2–15)

where

x is the chemical element,

a is one of the waters being mixed,

b is the other water being mixed,

m is a mixture of waters a and b,

R is the isotope ratio of the chemical element,

C is the concentration of the chemical element, 

and

f is the weight fraction of water a in the 

mixture [(a)/(a+b)].

References Cited

Bartholomay, R.C., Hopkins, C.B., and Maimer, N.V., 2015, 

Chemical constituents in groundwater from multiple zones in 

the Eastern Snake River Plain aquifer at the Idaho National 

Laboratory, Idaho, 2009–13: U.S. Geological Survey 

Scientific Investigations Report 2015-5002 (DOE/ID-22232), 

109 p., http://pubs.er.usgs.gov/publication/sir20155002.

Devore, J.L., 1995, Probability and statistics for engineering 

and the sciences (4th ed.): Belmont, Calif., Wadsworth 

Publishing Co., 743 p.

Faure, Gunter, 1986, Principles of Isotope Geology (2nd ed.): 

New York, John Wiley & Sons, 589 p.

Hem, J.D., 1992, Study and interpretation of the chemical 

characteristics of natural water (3d ed.): U.S. Geological 

Survey Water-Supply Paper 2254, 263 p., http://pubs.er.usgs.

gov/publication/wsp2254.

International Atomic Energy Agency/World Meteorological 

Organization, 2015, Global network of isotopes in 

precipitation database: International Atomic Energy Agency, 

accessed December 24, 2015, at http://www.iaea.org/water.

Mueller, D.K., 1998, Quality of nutrient data from streams 

and ground water sampled during 1993–95—National 

Water-Quality assessment Program: U.S. Geological Survey 

Open-File Report 98-276, 25 p., http://pubs.er.usgs.gov/

publication/ofr98276.

Plummer, L.N., Rupert, M.G., Busenberg, E., and Schlosser, P., 

2000, Age of irrigation water in ground water from the 

eastern Snake River Plain aquifer, south-central Idaho: 

Ground Water, v. 38, no. 2, p. 264–283.

Rattray, G.W., 2014, Evaluation of quality-control data 

collected by the U.S. Geological Survey for routine 

water-quality activities at the Idaho National Laboratory, 

southeastern Idaho, 2002–2008: U.S. Geological Survey 

Scientific Investigations Report 2014-5027 (DOE/ID-22228), 

65 p., http://pubs.usgs.gov/sir/2014/5027/.

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

measurements: Chelsea, Mich., Lewis Publishers, Inc., 

328 p.
194 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho
Appendix 3 195

Appendix 3. Description of Water Groups

Surface Water

Surface water in the study area includes the Big Lost 

River (BLR), Little Lost River (LLR), Birch Creek (BC), 

Camas Creek, and Mud Lake. Only the BLR and BC actually 

flow onto the INL and contribute recharge directly to 

groundwater at the INL.

Tributary Valley Groundwater

Tributary valley groundwater includes groundwater 

from the BLR, LLR, and BC valleys. Tributary valley 

groundwater flows south or southeast into the ESRP aquifer, 

so groundwater from the BLR valley may provide recharge to 

the southwestern corner of the INL and groundwater from the 

LLR and BC valleys provides recharge to the northern parts of 

the INL.

Regional Groundwater

Regional groundwater refers to groundwater flowing 

into the INL from hydrologically upgradient areas of the 

ESRP aquifer (Busenberg and others, 2001; Fisher and others, 

2012). Owing to the influence of agricultural practices and 

upwelling of geothermal water, the chemistry of some regional 

groundwater has been significantly altered from the typically 

dilute character of regional groundwater (Rattray, 2015). 

Consequently, regional groundwater includes 

1. Dilute groundwater north and east of Mud Lake (East 

Mud Lake Area; table 10) representative of groundwater 

from the Camas Creek drainage basin that was slightly 

influenced by infiltration of groundwater or surface 

water used for irrigation; 

2. Groundwater north of Mud Lake and near the 

Beaverhead Mountains (North Mud Lake Area; table 10) 

representative of groundwater from the Beaverhead 

Mountains and extensive infiltration of groundwater or 

surface water used for irrigation; 

3. Groundwater north and west of Mud Lake (West Mud 

Lake Area; table 10) representative of groundwater 

from the Beaver and Camas Creek drainage basins, the 

Beaverhead Mountains, and extensive infiltration of 

groundwater and (or) surface water used for irrigation; 

4. Groundwater north and west of Mud Lake influenced 

by upwelling geothermal water (groundwater with 

geothermal input; table 10) (Rattray, 2015); 

5. Groundwater southwest of Mud Lake (Southwest 

Mud Lake Area; table 10) representative of extensive 

infiltration of groundwater or surface water used for 

irrigation; and 

6. Dilute groundwater adjacent to the southeast boundary 

of the INL (Southeast INL Boundary Area; table 10) 

representative of regional groundwater in the ESRP 

aquifer east, southeast, and in the southeastern corner, 

of the INL that was slightly influenced by infiltration of 

groundwater used for irrigation.

Geothermal Water

Recharge of geothermal water to the ESRP aquifer within 

the study area occurs as upwelling of water from thousands 

of feet below the land surface of the ESRP (Mann, 1986) and 

perhaps from upwelling of deep water along faults and caldera 

boundaries along the transition zone between the ESRP and 

the mountains (McLing and others, 2002; Ginsbach, 2013). 

Geothermal water in the study area (table 12 and figs. 8A and

9) included groundwater from hot springs (Lidy Hot Springs 

and Warm Springs, sites ML 57 and ML 58, respectively) in 

the Beaverhead Mountains and groundwater pumped from 

borehole INEL-1 (at depths of 1,511–2,206 [site INEL-1 

2,000 feet] and 4,210–10,333 [site INEL-1 10,300 feet] feet 

below the land surface).

Deep Groundwater

Deep groundwater samples were collected from sites 

EBR-1, Site 9, Site 14, USGS 7, and USGS 15 (table 12 and 

fig. 9). These samples were representative of groundwater 

in the ESRP aquifer at the INL from depths greater than 

250 ft below the water table, and these wells have maximum 

open-interval depths of 284–626 ft below the water table 

(table 11). All of these deep wells are in the western part of the 

INL where, based on the chemistry of shallow groundwater, 

the primary source of water should be streams and (or) 

groundwater from the tributary valleys (Olmsted, 1962).

Contaminated Groundwater

Contaminated groundwater at the INL was initially 

identified using two criteria. First, only sample sites that 

were within or near a site facility discharging wastewater to 

the subsurface (table 8) or a contaminant plume extending 

downgradient from the site facilities (figs. 3B and 28BB; 
196 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

Bartholomay, Tucker, and others, 2000) could be influenced by 

discharge of wastewater. Second, contaminated groundwater 

was identified from tritium activities, where groundwater 

from sites that probably did not include significant recharge 

from the 1960s–70s and that had tritium activities exceeding 

the activity in precipitation at the INL for the year of 

sample collection were considered likely to contain tritium 

from wastewater discharge (fig. 13A). Using these criteria, 

groundwater at or downgradient of site facilities with tritium 

activities that exceeded 75 pCi/L was considered likely to be 

contaminated with tritium (fig. 28BB).

Additional criteria to identify contaminated groundwater 

were needed because (1) tritium was not analyzed from all 

samples and (2) non-radioactive and radioactive wastes were 

frequently discharged in wastewater to the subsurface using 

different disposal methods and (or) locations (Bartholomay, 

Tucker, and others, 2000), so some groundwater samples 

that probably were influenced by wastewater discharge of 

non-radioactive wastes may not have been influenced by 

wastewater discharge of tritium. Consequently, an additional 

criterion was that groundwater samples with sodium and 

sulfate concentrations exceeding 25 and 40 mg/L, respectively, 

were considered likely to be influenced by wastewater 

discharge. These concentrations exceeded the maximum 

concentrations for these constituents in samples that seem to 

be natural groundwater at the INL (table 13, figs. 28I and O). 

Another criterion used to identify contaminated 

groundwater was that samples from shallow groundwater 

at the INL with specific conductance values equal to or 

exceeding 600 μS/cm at 25 °C were considered likely to be 

influenced by wastewater discharge. This criterion was based 

on the distribution of specific conductance in figure 28B, 

which shows that values exceeding 600 μS/cm at 25 °C 

was detected only at or downgradient of site facilities and 

irrigated areas. 

The specific conductance criterion may not be reliable in 

groundwater south of the LLR valley and near Naval Reactors 

Facility (NRF) because some specific conductance values 

equaling or exceeding 600 μS/cm at 25 °C in this area may 

be due to irrigation in the LLR valley and not from waste 

discharge from the NRF. A statistical analysis (minimum, 

maximum, and mean values and standard deviation) of the 

ratio of chloride and nitrate concentrations (table 3-1) in 

groundwater from the NRF area was done to distinguish 

groundwater that was influenced by waste discharge 

from the NRF industrial waste ditch from groundwater 

that was influenced by irrigation in the LLR valley. 

These chemical constituents were selected for the statistical 

analysis because (1) large amounts of chloride discharged 

from the NRF industrial waste ditch (Bartholomay, Tucker, 

and others, 2000) generated large chloride concentrations in 

groundwater at NRF 6 (240 mg/L), which is adjacent to the 

ditch, compared to chloride concentrations in groundwater 

from the Ruby Farms well (50 mg/L), which was influenced 

by irrigation in the lower LLR valley and (2) nitrate 

concentrations in groundwater from the Ruby Farms well 

(2.9 mg/L as N) seem to be larger than nitrate concentrations 

in groundwater at NRF (nitrate concentrations at NRF were 

≤2.2 mg/L as N) that may be influenced by industrial sewage 

at NRF (fig. 28N). Recharge from the BLR with small 

concentrations of chloride (≤5 mg/L) and nitrate (≤0.2 mg/L 

as N) will dilute concentrations of these constituents in 

groundwater at the NRF but will not appreciably change the 

ratio of chloride to nitrate.

The statistical analysis performed for data from 19 wells 

included only pairs of chloride and nitrate data from water 

samples that were collected on the same day, included all 

data from 1975 through 2014, and consisted of 785 calculated 

ratios. Thirteen outlier data points2 (1.7 percent of the data), 

mostly nitrate concentrations, were excluded from the 

analysis. The statistical analysis showed that mean ratios of 

chloride and nitrate concentrations at individual wells were 

15–17 in water in the lower LLR valley (Harrell, Mays, 

Ruby Farms) or upgradient of the NRF industrial waste ditch 

(USGS 12), 77–181 in water from wells NRF 6 and NRF 13 

that are adjacent to the NRF industrial waste ditch, and 11–25 

in all wells downgradient of the waste ditch. This statistical 

analysis shows that wells NRF 6 and NRF 13 were influenced 

by discharge from the industrial waste ditch and that a large 

influence of discharge from the waste ditch was not apparent 

at the other wells (this analysis did not evaluate other, less 

intensive, waste discharge methods at NRF [U.S. Department 

of Energy, 2014]).

Based on all of these criteria, 34 groundwater samples 

were identified as probably influenced by wastewater 

discharge (contaminated groundwater in table 12), and all of 

these samples were collected at or downgradient of Advanced 

Test Reactor Complex (ATRC), Idaho Nuclear Technology 

and Engineering Center (INTEC), NRF, Radioactive Waste 

Management Complex (RWMC), and Test Area North (TAN). 

Contaminated groundwater at Central Facilities Area (CFA) 

included discharge of waste at CFA, but was predominantly 

from discharge of waste at INTEC and was considered part of 

the waste plume extending downgradient from INTEC. 

2

Outliers probably were due to errors in sample collection, processing, analysis, or data reporting (Rattray, 2012).
Appendix 3 197

Table 3-1. Statistical analysis of ratios of chloride and nitrate concentrations in groundwater in the vicinity of the Naval Reactors 

Facility, Idaho National Laboratory and vicinity, eastern Idaho.

[Locations of sites shown in figures 8–9. Abbreviations: NRF, Naval Reactors Facility]

Site name Years of data 

collection

Number of 

samples

Chloride-nitrate ratio Standard 

deviation

Number of 

Minimum Maximum Mean outliers

Wells in the lower Little Lost River valley

Harrell 1978, 1981, 1992, 1996, 

2000, 2005, 2010

7 8 28 15 6.3 0

Mays 1978, 2000 2 14 19 17 3.6 0

Ruby Farms 1991 1 17 17 17 na 0

Wells upgradient of the NRF Industrial Waste Ditch

USGS 12 1984, 1990–2014 80 10 22 17 2.2 1

Wells adjacent to the NRF Industrial Waste Ditch

NRF 6 1991–96, 2000–14 53 93 316 181 65 1

NRF 13 1996, 2000–10 28 35 98 77 14 0

Wells near or downgradient of the NRF Industrial Waste Ditch

Fire Station 2 1982–96 17 10 22 14 2.9 0

INEL 1 WS 1984–85, 1989–95 27 16 26 20 1.7 1

NRF 2 1987, 1989–95 27 20 29 25 2.1 1

1

NRF 7 1991–96, 2000–14 52 7.4 18 11 1.8 2

NRF 8 1996, 2000–14 34 13 20 17 1.8 1

NRF 9 1996, 2000–14 35 17 24 20 1.9 1

NRF 10 1996, 2000–14 35 20 27 23 1.8 0

NRF 11 1996, 2000–14 37 19 28 23 2.2 1

NRF 12 1996, 2000–14 35 16 32 23 3.6 0

USGS 97 1975, 1982–2014 91 13 28 17 2.1 1

USGS 98 1975, 1984–85, 

1989–2014

82 10 25 13 1.9 1

USGS 99 1975, 1984, 1989–96, 

2000–14

64 11 17 13 1.2 1

USGS 102 1990–2014 78 11 20 16 1.9 1

1

Outlier data point was from 1984.

Natural Groundwater

Natural groundwater refers to shallow groundwater 

(groundwater <250 ft below the water table) within or 

downgradient of the INL that probably was not influenced by 

wastewater. Thus, natural groundwater samples for this study 

include samples collected at or downgradient of the INL that 

were not included in discussions of sources of recharge, deep 

groundwater, or contaminated groundwater.

The chemistry of natural groundwater at the INL differs 

across the site in response to various sources of recharge, 

such as underflow of groundwater from the tributary valleys 

north of the INL, underflow of regional groundwater east of 

the INL, infiltration of irrigation water north and east of the 

INL, infiltration recharge from the BLR in the western part 

of the INL, and possibly local recharge from precipitation 

(Olmsted, 1962; Robertson and others, 1974, Busenberg and 

others, 2001). The 58 natural groundwater samples were 

grouped into 6 spatially defined areas (fig. 9) based on their 

similarity of potential source waters and chemical and isotopic 

compositions (figs. 28A–DD). The spatially defined areas at 

the INL are 

1. Groundwater near TAN (North INL Area) that may 

be representative of surface water from BC and 

groundwater from the BC valley; 

2. Groundwater east and southeast of TAN (Northeast 

INL Area) that may be representative of regional 

groundwater, upwelling of geothermal water or deep 

groundwater, and irrigation return flows; 

3. Groundwater in the southeast part of the INL and south 

of Atomic City (Southeast INL Area) that may be 

representative of regional groundwater and irrigation 

return flows; 
198 Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho

4. Groundwater between TAN and the southern boundary 

of the INL (Central INL Area) that may be representative 

of surface water from the BLR, tributary groundwater 

from the BC and (or) LLR valleys, upwelling of 

geothermal water or deep groundwater, and regional 

groundwater; 

5. Groundwater north and west of the BLR (Northwest INL 

Area) that may be representative of surface water from 

the BLR, tributary groundwater from the LLR valley, 

irrigation return flows, groundwater underflow from the 

Lost River Range, and precipitation; and 

6. Groundwater southwest of the ATRC, INTEC, and CFA 

(Southwest INL Area) that may be representative of 

surface water from the BLR, tributary groundwater from 

the LLR and (or) BLR valleys, and precipitation.

References Cited

Bartholomay, R.C., Tucker, B.J., Davis, L.C., and 

Greene, M.R., 2000, Hydrologic conditions and distribution 

of selected constituents in water, Snake River Plain aquifer, 

Idaho National Engineering and Environmental Laboratory, 

Idaho, 1996 through 1998: U.S. Geological Survey WaterResources Investigations Report 00-4192 (DOE/ID-22167), 

52 p.

Busenberg, Eurybiades, Plummer, L.N., and 

Bartholomay, R.C., 2001, Estimated age and source 

of the young fraction of ground water at the Idaho 

National Engineering and Environmental Laboratory: 

U.S. Geological Survey Water-Resources Investigations 

Report 01-4265 (DOE/ID-22177), 144 p., http://pubs.

er.usgs.gov/publication/wri014265.

Fisher, J.C., Rousseau, J.R., Bartholomay, R.C., and 

Rattray, G.W., 2012, A comparison of U.S. Geological 

Survey three-dimensional model estimates of groundwater 

source areas and velocities to independently derived 

estimates, Idaho National Laboratory and vicinity, Idaho: 

U.S. Geological Survey Scientific Investigations Report 

2012-5152 (DOE/ID-22218), 130 p.

Ginsbach, M.L., 2013, Geochemical evolution of groundwater 

in the Medicine Lodge Creek drainage basin, eastern Idaho: 

Pocatello, Idaho State University, M.S. Thesis, 241 p., 

http://geology.isu.edu/thesis/Ginsbach.Michael.2013.pdf.

Mann, L.J., 1986, Hydraulic properties of rock units and 

chemical quality of water for INEL-1—A 10,365-foot 

deep test hole drilled at the Idaho National Engineering 

Laboratory, Idaho: U.S. Geological Survey Water-Resources 

Investigations Report 86-4020 (DOE/ID-22070), 23 p., 

http://pubs.er.usgs.gov/publication/wri864020.

McLing, T.L., Smith, R.W., and Johnson, T.M., 2002, 

Chemical characteristics of thermal water beneath the 

eastern Snake River Plain: in Link, P.K., and Mink, L.L. 

eds., Geology, Hydrogeology, and Environmental 

Restoration—Idaho National Engineering and 

Environmental Laboratory, Eastern Snake River Plain, 

Idaho: Boulder, Colorado, Geological Society of America 

Special Paper 353, p. 205–211.

Olmsted, F.H., 1962, Chemical and physical characteristics of 

ground water in the National Reactor Testing Station, Idaho: 

U.S. Atomic Energy Commission, Idaho Operations Office 

Publication IDO-22043-USGS, 142 p.

Rattray, G.W., 2012, Evaluation of quality-control 

data collected by the U.S. Geological Survey for 

routine water-quality activities at the Idaho National 

Laboratory, southeastern Idaho, 1996–2001: U.S. 

Geological Survey Scientific Investigations Report 

2012‐5270 (DOE/ ID-22222), 74 p., http://pubs.usgs.gov/

sir/2012/5270/.

Rattray, G.W., 2015, Geochemical evolution of groundwater 

in the Mud Lake area, eastern Idaho, USA: Environmental 

Earth Sciences, v. 73, no. 12, p. 8,251–8,269, http://link.

springer.com/article/10.1007/s12665-014-3988-9/.

Robertson, J.B., Schoen, Robert, and Barraclough, J.T., 1974, 

The influence of liquid waste disposal on the geochemistry 

of water at the National Reactor Testing Station, Idaho—

1952–1970: U.S. Geological Survey Open-File Report 

(IDO-22053), 231 p., http://pubs.er.usgs.gov/publication/

ofr73238.

U.S. Department of Energy, 2014, Naval Reactors Facility 

Environmental Summary Report: U.S. Department of 

Energy, NRFOSQ-ESH-EE-14-003, 44 p.
Publishing support provided by the U.S. Geological Survey 

Science Publishing Network, Tacoma Publishing Service Center

For more information concerning the research in this report, contact the 

Director, Idaho Water Science Center

U.S. Geological Survey 

230 Collins Road

Boise, Idaho 83702

http://id.water.usgs.gov
Rattray—Geochemistry of Groundwater in the Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Eastern Idaho—Professional Paper 1837–A

ISSN 2330-7102 (online)

https://doi.org/10.3133/pp1837A