Steady-State and Transient Models of Groundwater 

Flow and Advective Transport, Eastern Snake River 

Plain Aquifer, Idaho National Laboratory and Vicinity, 

Idaho

Scientific Investigations Report 2010–5123

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

U.S. Department of the Interior

U.S. Geological Survey

DOE/ID-22209
Cover: A three-dimensional solid contour plot using a smooth coloring scheme to 

represent simulated steady-state hydraulic heads within model layers 3 through 6. 

Particle pathlines representing tritium movement from 1953 to 1968 are displated as 

narrow tubes in model layers 1 and 2. The viewpoint of the graphic is downward from 

the south-southwest.
Steady-State and Transient Models of 

Groundwater Flow and Advective Transport, 

Eastern Snake River Plain Aquifer, Idaho 

National Laboratory and Vicinity, Idaho

By Daniel J. Ackerman, Joseph P. Rousseau, Gordon W. Rattray, and 

Jason C. Fisher 

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

Scientific Investigations Report 2010–5123

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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Suggested citation:

Ackerman, D.J., Rousseau, J.P., Rattray, G.W., and Fisher, J.C., 2010, Steady-state and transient models of 

groundwater flow and advective transport, Eastern Snake River Plain aquifer, Idaho National Laboratory and vicinity, 

Idaho: U.S. Geological Survey Scientific Investigations Report 2010-5123, 220 p.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.
iii

Contents

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

Introduction.....................................................................................................................................................2

Purpose and Scope ..............................................................................................................................4

Description of Model Area..................................................................................................................6

Hydrogeologic Setting .........................................................................................................................6

Previous Investigations........................................................................................................................8

Conceptual Model..........................................................................................................................................9

Hydrogeologic Framework..................................................................................................................9

Hydrogeologic Units..................................................................................................................11

Older Rocks that Underlie the Base of the Aquifer..............................................................15

Sediment Interbeds ...................................................................................................................18

Rhyolite Domes...........................................................................................................................18

Volcanic Rift Zones, Vents, and Vent Corridors ....................................................................20

Conceptual Model Boundaries and Fluxes ....................................................................................20

Inflow Boundaries .....................................................................................................................20

Outflow Boundaries...................................................................................................................29

No-Flow Boundaries .................................................................................................................29

Conceptualization of Groundwater Flow and Contaminant Transport ......................................29

Numerical Model .........................................................................................................................................32

Model Discretization ..........................................................................................................................33

Spatial Discretization ................................................................................................................33

Temporal Discretization............................................................................................................36

Boundary Conditions..........................................................................................................................37

Water-Table Boundary..............................................................................................................37

Northwest Mountain-Front Boundary....................................................................................41

Northeast Boundary..................................................................................................................41

Well Injection and Withdrawal................................................................................................41

Southwest Boundary.................................................................................................................41

Model Calibration.........................................................................................................................................42

Calibration Observations ...................................................................................................................42

Observations for Steady-State Model Calibration ...............................................................42

Observations for Transient Model Calibration......................................................................42

Observation Weights.................................................................................................................42

Statistical Methods Used for Model Evaluation............................................................................44

Evaluation of Model Fit .............................................................................................................44

Evaluation of Parameter Estimates.........................................................................................45

Steady-State Calibration ...................................................................................................................46

Hydrogeologic Zones ................................................................................................................47

Model Parameters.....................................................................................................................55

Model Results and Evaluation .................................................................................................55
iv

Contents—Continued

Model Calibration—Continued

Transient Calibration ..........................................................................................................................77

Initial Conditions ........................................................................................................................77

Model Parameters.....................................................................................................................77

Model Results and Evaluation .................................................................................................78

Analysis of Advective Flow and Transport ..............................................................................................96

Comparison of Steady-State and Transient Flow..........................................................................96

Analysis of Steady-State and Transient Flow Paths ............................................................99

Evaluation of Transient Flow Influence on Particle Paths ................................................103

Representativeness of Flow Directions and Average Linear Particle Velocities .........104

Comparison of Flow During a Wet- and a Dry-Climate Cycle....................................................107

Analysis of Flow Paths During a Wet- and a Dry-Climate Cycle......................................107

Evaluation of Short-Term Climate Cycles Influence on Particle Paths...........................110

Evaluation of Flow and Transport in the Southwestern Part of Idaho National 

Laboratory ............................................................................................................................111

Particle-Tracking Simulation Scenarios for Tritium Releases at INTEC and RTC, 

1953–68.........................................................................................................................114

Description and Comparison of Tritium and Particle Plumes...........................................119

Simulated Particle Velocities Compared to Velocities Based on Peak and 

First Arrivals of Tritium ..............................................................................................127

Summary and Conclusions.......................................................................................................................131

Acknowledgments.....................................................................................................................................134

References Cited........................................................................................................................................134

Appendix A. Data for Wells, Boreholes, and Streams Used in the Construction and 

Calibration of Steady-State and Transient Models of Groundwater Flow, Idaho 

National Laboratory and Vicinity, Idaho...................................................................................141

Appendix B. Locations of Wells and Streams for Which Stratigraphic, Water-Level, 

Water -Use and Discharge Data are Available, Idaho National Laboratory

and Vicinity, Idaho...................................................................................... .................................155

Appendix C. Average Streamflow and Infiltration Used for Steady-State and Transient

Models of Groundwater Flow, Idaho National Laboratory and Vicinity, Idaho..................165

Appendix D. Industrial Wastewater Disposal to Model Layer 1 Used for Steady-State and 

Transient Models of Groundwater Flow, Idaho National Laboratory, Idaho ......................173

Appendix E. Irrigation Well Withdrawals Used for Steady-State and Transient Models of 

Groundwater Flow, Idaho National Laboratory and Vicinity, Idaho.....................................177

Appendix F. Industrial Well Withdrawals or Injections Used for Steady-State and Transient 

Models of Groundwater Flow, Idaho National Laboratory, Idaho........................................181

Appendix G. Water-Level Data Used to Represent 1980 Steady-State Head for Calibration 

of Steady-State and Transient Models of Groundwater Flow, Idaho National 

Laboratory and Vicinity, Idaho ...................................................................................................201

Appendix H. Water-Level Data Used for Calibration of Transient Model of Groundwater 

Flow, Idaho National Laboratory and Vicinity, Idaho..............................................................209

Appendix I. Tritium Disposal and Production Well Pumpage at Idaho Nuclear Technology 

and Engineering Center and Reactor Technology Complex, Idaho National 

Laboratory, Idaho .........................................................................................................................217
v

Figures

Figure 1. Map showing the location of the Idaho National Laboratory, the model area, 

selected facilities, wells, boreholes, streamflow-gaging stations, and Craters 

of the Moon National Monument, Idaho ................................................ 3

Figure 2. Map showing locations of documented contaminant plumes in the eastern 

Snake River Plain aquifer that exceed or have exceeded maximum contaminant 

levels for drinking water as defined by the U.S. Environmental Protection 

Agency, Idaho National Laboratory and vicinity, Idaho................................. 5

Figure 3. Map showing direction of regional groundwater flow, discharge areas, and 

irrigated acreage, eastern Snake River Plain, Idaho.................................... 7

Figure 4. Maps showing locations of wells and boreholes used to define base of the 

aquifer, basalt stratigraphy, hydraulic properties of the media, and altitudes 

of the water table, Idaho National Laboratory and vicinity, Idaho..................... 10

Figure 5. Map showing distribution of hydrogeologic units at the water table and 

cross section along line of section A–A’, Idaho National Laboratory and 

vicinity, Idaho .............................................................................. 12

Figure 6. Map and geologic section showing aquifer altitude and thickness as defined 

by borehole data and surface-based electrical-resistivity surveys, Idaho 

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

Figure 7. Maps showing water-table contours and areas of abundant sediment in the 

model area, Idaho National Laboratory and vicinity, Idaho ........................... 19

Figure 8. Map and geologic section showing location of the water table, northwest 

mountain-front, northeast regional-underflow, southwest regional-underflow, 

southeast flowline, and base of the aquifer boundaries, Idaho National 

Laboratory and vicinity, Idaho ............................................................ 21

Figure 9. Map showing generalized 1980 groundwater budget components for the 

model area, Idaho National Laboratory and vicinity, Idaho ........................... 22

Figure 10. Hydrographs showing annual mean discharge at streamflow-gaging 

stations on the Big Lost River, Idaho, for 1965–2002 .................................... 25

Figure 11. Hydrographs showing water levels in wells Arbor Test, USGS 12, USGS 9, 

and USGS 25 for 1948–2003, Idaho National Laboratory and vicinity, Idaho ......... 26

Figure 12. Maps showing water-level changes for July 1981 to July 1985, April–

August 1988 to April–August 1991, March–May 1991 to March–May 1995, 

and March–May 1995 to March–May 1998, Idaho National Laboratory and 

 vicinity, Idaho .............................................................................. 27

Figure 13. Map and geologic section showing distribution of hydrogeologic units and 

direction of groundwater flow at the water table and water-table contours 

for 1980, Idaho National Laboratory and vicinity, Idaho................................. 30

Figure 14. Map showing model domain and locations of head-dependent, specified 

flow, and river boundary conditions for layer 1 used for 0.5- and 0.25-mile 

model grids for models of groundwater flow, Idaho National Laboratory and 

vicinity, Idaho .............................................................................. 34

Figure 15. Geologic section showing the vertical discretization and distribution of the 

model layers and hydrogeologic units for models of groundwater flow, Idaho 

National Laboratory and vicinity, Idaho................................................... 35

Figure 16. Graph showing monthly mean discharge at streamflow-gaging station 

Big Lost River near Arco for water years 1946 through 2006........................... 36

Figure 17. Hydrograph showing stress periods and water levels at wells MTR TEST 

and USGS 27, 1981 through 1983, Idaho National Laboratory, Idaho .................. 36
vi

Figures—Continued

Figure 18. Map showing distribution of areas where returned water from irrigation 

and industrial use infiltrates as used in the calibration of groundwater flow 

models, Idaho National Laboratory and vicinity, Idaho ................................. 40

Figure 19. Maps showing distribution of hydrogeologic zones for model layer 1, layer 2, 

layer 3, layer 4, layer 5, and layer 6 for Big Lost Trough parameter structure used 

to simulate steady-state and transient groundwater flow at the Idaho National 

Laboratory and vicinity, Idaho ............................................................ 49

Figure 20. Graphs showing normalized composite scaled sensitivities for models of 

steady-state groundwater flow, Idaho National Laboratory and vicinity, Idaho ... 56

Figure 21. Graph showing estimated values of parameters with 95-percent confidence 

intervals and ranges of expected values for Big Lost Trough model of 

steady-state groundwater flow, Idaho National Laboratory and vicinity, Idaho ... 59

Figure 22. Graph showing normal probability plot for Big Lost Trough model of steady-state 

groundwater flow, Idaho National Laboratory and vicinity, Idaho..................... 61

Figure 23. Map showing observed and simulated water table for 1980 showing relation 

to hydrogeologic zones in layer 1 for Big Lost Trough model of steady-state 

groundwater flow, Idaho National Laboratory and vicinity, Idaho..................... 63

Figure 24. Graphs showing weighted residuals as a function of weighted simulated 

values of head for wells open exclusively to model layer 1, wells not open 

exclusively to layer 1, all wells, and weighted residuals as a function of 

simulated values for Big Lost Trough model of steady-state groundwater flow, 

Idaho National Laboratory and vicinity, Idaho .......................................... 67

Figure 25. Maps showing distribution of weighted residuals of head for wells open 

exclusively to model layer 1, wells not open exclusively to model layer 1, and 

all wells for Big Lost Trough model of steady-state groundwater flow, Idaho 

National Laboratory and vicinity, Idaho................................................... 71

Figure 26. Graph showing ranges of values and sensitivity of the objective function to 

values of specific storage for model of transient groundwater flow, Idaho 

National Laboratory and vicinity, Idaho................................................... 78

Figure 27. Graph showing estimated values of specific yield with 95-percent confidence 

intervals for model of transient groundwater flow, Idaho National Laboratory 

and vicinity, Idaho ........................................................................... 79

Figure 29. Graph showing normal probability plot for model of transient groundwater 

flow, Idaho National Laboratory and vicinity, Idaho .................................... 81

Figure 28. Graph showing composite scaled sensitivities for model of transient 

groundwater flow, Idaho National Laboratory and vicinity, Idaho .................. 81

Figure 30. Maps showing comparison of simulated water table, December 1987 and 

observed and simulated water table, April 1995, Idaho National Laboratory and 

vicinity, Idaho .............................................................................. 83

Figure 31. Hydrographs showing observed and simulated hydraulic head, head-difference 

observation times, and residuals of head difference for wells MTR TEST, 

USGS 87, USGS 25, and USGS 18 at various locations in the transient model 

of groundwater flow, Idaho National Laboratory, Idaho .............................. 85

Figure 32. Graph showing distribution of weighted residuals of head difference for model 

of transient groundwater flow, Idaho National Laboratory and vicinity, Idaho ...... 90

Figure 33. Graph showing distribution of weighted residuals of head difference over 

time for model of transient groundwater flow, Idaho National Laboratory and 

vicinity, Idaho .............................................................................. 91
vii

Figures—Continued

Figure 34. Graph showing distribution of annual and select monthly head-difference 

observations and residuals of head differences over time for model of transient 

groundwater flow, Idaho National Laboratory and vicinity, Idaho..................... 92

Figure 35. Maps showing distribution of weighted residuals of head difference for the 

end of December 1987, stress period 22, and December 1993, stress period 43, 

for model of transient groundwater flow, Idaho National Laboratory and 

vicinity, Idaho .............................................................................. 93

Figure 36. Map showing simulated water-table rise from January 1981 through 

December 1984, Idaho National Laboratory and vicinity, Idaho ..................... 97

Figure 37. Graphs showing observed and simulated hydraulic head, head-difference 

observation times, and residuals of head difference for wells USGS 9 and 

USGS 87 from 1981 through 1995, Idaho National Laboratory, Idaho.................. 98

Figure 38. Map showing pathlines representing 10-year particle-tracking simulations 

under steady-state and transient flow conditions, Idaho National Laboratory 

and vicinity, Idaho ...........................................................................100

Figure 39. Map showing flow directions and average linear groundwater velocities 

based on tritium/helium-3 and chlorofluorocarbon model ages of the young 

fraction of groundwater and assumed first and peak arrivals of chlorine-36 

at selected wells, Idaho National Laboratory and vicinity, Idaho .....................106

Figure 40. Map showing pathlines representing particle-tracking simulations for a 

4-year wet cycle (1983 through 1986) and a 4-year dry cycle (1989 through 

1992) under transient flow conditions, Idaho National Laboratory and vicinity, 

Idaho ..........................................................................................108

Figure 41. Map showing location of tritium concentrations greater than 2,000 and 500 

picocuries per liter, in 1968 and 1985, respectively, and monitoring wells used 

to compare model-derived average linear groundwater velocities to 

independently derived velocities, Idaho National Laboratory and vicinity, 

Idaho ..........................................................................................112

Figure 42. Graphs showing annual amount of tritium discharged in wastewater, annual 

wastewater disposal, and annual groundwater withdrawals, Idaho Nuclear 

Technology and Engineering Center and Reactor Technology Complex, 

1953–1968, Idaho National Laboratory, Idaho ..........................................117

Figure 43. Graphs showing annual mean discharge at streamflow-gaging station Big Lost 

River near Arco, and streamflow infiltration at Big Lost River Sinks, Playas, and 

spreading areas, and from model boundary to the Big Lost River Sinks, 1953 

through 1968, Idaho National Laboratory and vicinity, Idaho...........................119

Figure 44. Graph showing tritium concentration gradients defining the leading edge 

of the tritium plume downgradient of the Idaho Nuclear Technology and 

Engineering Center in 1968 (2,000 pCi/L isopleth) and in 1985 (500 pCi/L isopleth), 

Idaho National Laboratory, Idaho .........................................................121

Figure 45. Map showing particle plumes simulating the advective transport of tritium 

from the Idaho Nuclear Technology and Engineering Center and the Reactor 

Technology Complex for 16 years under steady-state flow conditions in 1980 and 

transient flow conditions from 1953 through 1968, Idaho National Laboratory and 

vicinity, Idaho ..............................................................................124

Figure 46. Graph showing concentrations of tritium in wastewater discharged at the 

Idaho Nuclear Technology and Engineering Center from 1964 through 1988 and 

concentrations of tritium in water from monitoring well USGS 36 from 1966 

through 1988, Idaho National Laboratory, Idaho .......................................129
viii

Figures—Continued

Figure 47. Map showing pathline and cumulative travel times for a particle simulating 

steady-state groundwater flow from the Idaho Nuclear Technology and 

Engineering Center disposal well (CPP 3) to the southern boundary of the 

Idaho National Laboratory used to evaluate model-derived travel times to 

selected wells, Idaho National Laboratory and vicinity, Idaho ........................130

Tables

Table 1. Summary of surface and subsurface wastewater disposal at selected facilities, 

Idaho National Laboratory, Idaho ......................................................... 4

Table 2. Composite unit stratigraphy used to define hydrogeologic units and older rocks, 

Idaho National Laboratory and vicinity, Idaho .......................................... 11

Table 3. Ranges of hydraulic conductivities and porosities for hydrogeologic units 

and older rocks and summary statistics of basalt flow thickness within 

hydrogeologic units, Idaho National Laboratory and vicinity, Idaho .................. 14

Table 4. Summary of conceptual model boundary characteristics, estimated 1980 inflows 

and outflows, and water budget, Idaho National Laboratory and vicinity, Idaho ... 23

Table 5. Steady-state and transient simulated water budgets, Idaho National Laboratory 

and vicinity, Idaho ........................................................................... 39

Table 6. Summary of open intervals for well completions by hydrogeologic unit and 

model layer for observation wells used in model calibration, Idaho National 

Laboratory and vicinity, Idaho ............................................................ 43

Table 7. Weights for steady-state and transient model observations, Idaho National 

Laboratory and vicinity, Idaho ............................................................ 44

Table 8. Hydraulic property parameters and corresponding zones used in parameter 

structures for steady-state and transient models, Idaho National Laboratory 

and vicinity, Idaho ........................................................................... 48

Table 9. Estimates of hydraulic properties, expected intervals, and 95-percent 

confidence intervals for calibrated steady-state models of groundwater flow, 

Idaho National Laboratory and vicinity, Idaho .......................................... 57

Table 10. Statistical measures related to parameter uncertainty and overall goodness 

of model fit for steady-state models of groundwater flow, Idaho National 

Laboratory and vicinity, Idaho ............................................................ 57

Table 11. Ranges and central values of hydraulic conductivity estimated from aquifer 

tests, Idaho National Laboratory and vicinity, Idaho .................................... 60

Table 12. Summary of observations and corresponding parameters with highest values 

of influence measures for steady-state model of groundwater flow, Idaho 

National Laboratory and vicinity, Idaho................................................... 61

Table 13. Observed and simulated steady-state vertical directions and gradients of 

groundwater flow in open boreholes, piezometer nests, and packer-isolated 

intervals of boreholes, Idaho National Laboratory, Idaho .............................. 65

Table 14. Regression statistics and estimated values of parameters for base case and 

alternative steady-state models of groundwater flow, Idaho National Laboratory 

and vicinity, Idaho ........................................................................... 75
ix

Tables—Continued

Table 15. Estimates of specific yield, expected intervals, and 95-percent confidence 

intervals for calibrated model of transient groundwater flow, Idaho National 

Laboratory and vicinity, Idaho ............................................................ 78

Table 16. Statistical measures related to parameter uncertainty and overall goodness 

of model fit for model of transient groundwater flow, Idaho National Laboratory 

and vicinity, Idaho ........................................................................... 81

Table 17. Summary of observations and corresponding parameters with highest values 

of influence measures for model of transient groundwater flow, Idaho National 

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

Table 18. Observed and simulated transient directions and gradients of groundwater 

flow in open boreholes, piezometer nests, and packer-isolated intervals of 

wells, Idaho National Laboratory, Idaho ................................................ 88

Table 19. Estimated effective porosity for groundwater model hydrogeologic zones, 

Idaho National Laboratory and vicinity, Idaho .......................................... 96

Table 20. Summary comparison of particle divergence, net distances traveled, and 

average linear velocities at the end of a 10-year simulation period under 1980 

steady-state flow conditions and transient flow conditions from 1983 through 

1992, Idaho National Laboratory and vicinity, Idaho ....................................101

Table 21. Average linear groundwater velocities calculated based on tritium/helium-3 

and chlorofluorocarbon model ages of the young fraction of groundwater and 

assumed first and peak arrivals of chlorine-36, between selected wells, Idaho 

National Laboratory and vicinity, Idaho...................................................105

Table 22. Summary comparison of particle divergence, distances traveled, and average 

linear velocities at the end of simulations for a wet cycle (1983 through 1986) 

and a dry cycle (1989 through 1992), Idaho National Laboratory and vicinity, 

Idaho ..........................................................................................109

Table 23. Measured tritium concentrations used to define the leading edge of the 

tritium plume in 1968 and 1985, Idaho National Laboratory and vicinity, Idaho ......113

Table 24. Summary of tritium disposal, wastewater disposal, and groundwater 

withdrawals at the Idaho Nuclear Technology and Engineering Center and 

the Reactor Technology Complex used to simulate the growth of tritium 

plumes in the eastern Snake River Plain aquifer under steady-state conditions 

from 1980 and transient flow conditions from 1953 to 1968, Idaho National 

Laboratory, Idaho ...........................................................................115

Table 25. Groundwater and particle velocities based on the assumed position and 

extended definition of the leading edge of the tritium plume of 1968, transient 

particle-plume and steady-state particle-pathline simulations, peak and first 

arrivals of tritium, tritium/helium-3 ages of the “young fraction” of groundwater, 

and first and peak arrivals of chlorine-36 at wells downgradient of the Idaho 

Nuclear Technology and Engineering Center and the Reactor Technology 

Complex, Idaho National Laboratory and vicinity, Idaho ..............................123

Table 26. Tritium concentrations in water collected from well Middle 2051, Idaho 

National Laboratory, Idaho ...............................................................128
x

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2)

square foot (ft2

) 0.09290 square meter (m2)

square mile (mi2

) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L) 

acre-foot (acre-ft) 1,233 cubic meter (m3)

Flow rate

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

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

foot per year (ft/yr) 0.3048 meter per year (m/yr)

cubic foot per second (ft3

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

cubic foot per second per square

mile [(ft3/s)/mi2]

0.01093 cubic meter per second per square

kilometer [(m3/s)/km2]

Radioactivity

curie (Ci) 37,000 megabecquerel (MBq)

curie per year (Ci/yr) 37,000 megabecquerel per year (MBq/yr)

picocurie per milliliter (pCi/mL) 0.037 becquerel per milliliter (Bq/mL)

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.

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

or micrograms per liter (μg/L).

Conversion Factors, Datums, and Abbreviations and 

Acronyms

Conversion Factors
xi

Datums

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1988 

(NGVD 29).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

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

The projection Albers used in the North American Datum of 1927, a central meridian of 113°W., 

standard parallels of 42° 50’ N. and 44° 10’ N., a false easting of 656,166.67 ft, and the latitude of 

projection’s origin was 41° 30’ N.

Abbreviations and Acronyms

Abbreviation 

or Acronym Definition

ANL Argonne National Laboratory (now MFC)

CFA Central Facilities Area

CPP Chemical Processing Plant (changed to ICPP, then INTEC)

CU composite unit

DOE U.S. Department of Energy

EBR Experimental Breeder Reactor

ESRP Eastern Snake River Plain

HC hydraulic conductivity

ICPP Idaho Chemical Processing Plant (formerly CPP, now INTEC)

INL Idaho National Laboratory

INTEC Idaho Nuclear Technology and Engineering Center (formerly ICPP)

LSIT large-scale infiltration test

MFC Materials and Fuels Complex (formerly ANL)

NRF Naval Reactors Facility

RASA Regional Aquifer System Analysis

RTC Reactor Technology Complex (formerly TRA)

RWMC Radioactive Waste Management Complex

SDA Subsurface Disposal Area

SS specific storage

SY specific yield

TAN Test Area North

TRA Test Reactor Area (now RTC)

USGS U.S. Geological Survey

VANI ratio of horizontal to vertical hydraulic conductivity
xii

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Steady-State and Transient Models of Groundwater 

Flow and Advective Transport, Eastern Snake River Plain 

Aquifer, Idaho National Laboratory and Vicinity, Idaho

By Daniel J. Ackerman, Joseph P. Rousseau, Gordon W. Rattray, and Jason C. Fisher

Abstract

Three-dimensional steady-state and transient models of 

groundwater flow and advective transport in the eastern Snake 

River Plain aquifer were developed by the U.S. Geological 

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

The steady-state and transient flow models cover an area of 

1,940 square miles that includes most of the 890 square miles 

of the Idaho National Laboratory (INL). A 50-year history 

of waste disposal at the INL has resulted in measurable 

concentrations of waste contaminants in the eastern Snake 

River Plain aquifer. Model results can be used in numerical 

simulations to evaluate the movement of contaminants in the 

aquifer. 

Saturated flow in the eastern Snake River Plain aquifer 

was simulated using the MODFLOW-2000 groundwater flow 

model. Steady-state flow was simulated to represent conditions 

in 1980 with average streamflow infiltration from 1966–80 

for the Big Lost River, the major variable inflow to the 

system. The transient flow model simulates groundwater flow 

between 1980 and 1995, a period that included a 5-year wet 

cycle (1982–86) followed by an 8-year dry cycle (1987–94). 

Specified flows into or out of the active model grid define the 

conditions on all boundaries except the southwest (outflow) 

boundary, which is simulated with head-dependent flow. In 

the transient flow model, streamflow infiltration was the major 

stress, and was variable in time and location. The models 

were calibrated by adjusting aquifer hydraulic properties 

to match simulated and observed heads or head differences 

using the parameter-estimation program incorporated in 

MODFLOW-2000. Various summary, regression, and 

inferential statistics, in addition to comparisons of model 

properties and simulated head to measured properties and 

head, were used to evaluate the model calibration. 

Model parameters estimated for the steady-state 

calibration included hydraulic conductivity for seven of 

nine hydrogeologic zones and a global value of vertical 

anisotropy. Parameters estimated for the transient calibration 

included specific yield for five of the seven hydrogeologic 

zones. The zones represent five rock units and parts of four 

rock units with abundant interbedded sediment. All estimates 

of hydraulic conductivity were nearly within 2 orders of 

magnitude of the maximum expected value in a range that 

exceeds 6 orders of magnitude. The estimate of vertical 

anisotropy was larger than the maximum expected value. All 

estimates of specific yield and their confidence intervals were 

within the ranges of values expected for aquifers, the range of 

values for porosity of basalt, and other estimates of specific 

yield for basalt. 

The steady-state model reasonably simulated the 

observed water-table altitude, orientation, and gradients. 

Simulation of transient flow conditions accurately reproduced 

observed changes in the flow system resulting from 

episodic infiltration from the Big Lost River and facilitated 

understanding and visualization of the relative importance 

of historical differences in infiltration in time and space. 

As described in a conceptual model, the numerical model 

simulations demonstrate that flow is (1) dominantly horizontal 

through interflow zones in basalt and vertical anisotropy 

resulting from contrasts in hydraulic conductivity of various 

types of basalt and the interbedded sediments, (2) temporally 

variable due to streamflow infiltration from the Big Lost River, 

and (3) moving downward downgradient of the INL.

The numerical models were reparameterized, recalibrated, 

and analyzed to evaluate alternative conceptualizations or 

implementations of the conceptual model. The analysis of the 

reparameterized models revealed that little improvement in the 

model could come from alternative descriptions of sediment 

content, simulated aquifer thickness, streamflow infiltration, 

and vertical head distribution on the downgradient boundary. 

Of the alternative estimates of flow to or from the aquifer, 

only a 20 percent decrease in the largest inflow, the northeast 

boundary underflow, resulted in a recalibrated parameter value 

just outside the confidence interval of the base-case calibrated 

value.
2 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Particle-tracking calculations using the particle-tracking 

program MODPATH were used to evaluate (1) how simulated 

groundwater flow paths and travel times differ between the 

steady-state and transient flow models, (2) how wet- and 

dry-climate cycles affect groundwater flow paths and travel 

times, and (3) how well model-derived groundwater flow 

directions and velocities compare to independently derived 

estimates. Particle tracking also was used to simulate the 

growth of tritium (3H) plumes originating at the Idaho 

Nuclear Technology and Engineering Center and the Reactor 

Technology Complex over a 16-year period under steady‐state

and transient flow conditions (1953–68). The shape, 

dimensions, and areal extent of the 3H plumes were compared 

to a map of the plumes for 1968 from 3H releases at the Idaho 

Nuclear Technology and Engineering Center and the Reactor 

Technology Complex beginning in 1952.

Collectively, the particle-tracking simulations indicate 

that average linear groundwater velocities, based on estimates 

of porosity, and flow paths are influenced by two primary 

factors: (1) the dynamic character of the water table and 

(2) the large contrasts in the hydraulic properties of the media, 

primarily hydraulic conductivity. The simulated growth and 

decay of groundwater mounds as much as 34 ft above the 

steady-state water table beneath the Big Lost River spreading 

areas, sinks, and playas, and to a lesser extent beneath the Big 

Lost River channel lead to non-uniform changes in the altitude 

of the water table throughout the model area. These changes 

affect the orientation and magnitude of water-table gradients 

and affect groundwater flow directions and velocities to a 

greater or lesser degree depending on the magnitude, duration, 

and proximity of the transient stress. Simulation results 

also indicate that temporal changes in the local hydraulic 

gradient can account for some of the observed dispersion 

of contaminants in the aquifer near the major sources of 

contamination at the INTEC and the RTC and perhaps most 

observed dispersion several miles downgradient of these 

facilities. The distance downgradient of the INTEC that 

simulated particle plumes were able to reasonably reproduce 

the shape and dimensions of the 1968 3H plume extended only 

to the boundary of zones of abundant sediment, about 4 miles 

downgradient of the INTEC. This boundary encompasses the 

entire area represented by the 1968 25,000 picocuries/liter 3H 

isopleths. Particle plumes simulated beyond this boundary 

were narrow and long, and did not reasonably reproduce the 

shape, dimensions, or position of the leading edge of the 3H 

plume as shown in earlier reports; however, as noted in an 

assessment of the interpreted plume, few data were available 

in 1968 to characterize its true areal extent and shape.

Introduction

The Idaho National Laboratory (INL) was established 

by the U.S. Atomic Energy Commission, now the U.S. 

Department of Energy (DOE), in 1949 to build, operate, 

and test nuclear reactors. The scope of work at the INL 

increased from the 1950s through the 1970s to include other 

nuclear‐research programs, the reprocessing of spent nuclear

fuel, and the storage and disposal of radioactive waste. A 

history of more than 50 years of waste disposal associated 

with nuclear-reactor research and nuclear-fuel reprocessing 

at the INL has resulted in measurable concentrations of 

contaminants in the eastern Snake River Plain (ESRP) aquifer 

beneath the INL. 

The INL covers an area of about 890 mi2 and overlies 

the west-central part of the ESRP in southeast Idaho (fig. 1). 

The underlying ESRP aquifer, designated as a sole source 

aquifer by the U.S. Environmental Protection Agency (1991), 

is a major source of water for agricultural, industrial, and 

domestic use in southeast Idaho. Wastewater disposal sites at 

the Test Area North (TAN), Naval Reactors Facility (NRF), 

Reactor Technology Complex (RTC, formerly known as 

Test Reactor Area, or TRA), and Idaho Nuclear Technology 

and Engineering Center (INTEC, formerly known as the 

Idaho Chemical Processing Plant, or ICPP) (fig. 1) have 

been primary sources of radioactive and chemical waste 

contaminants in water from the ESRP aquifer. These 

wastewater disposal sites have, in the past, included lined 

evaporation ponds, unlined infiltration ponds and ditches, 

drain fields, and injection wells. Waste materials buried in 

shallow pits and trenches within the Subsurface Disposal 

Area (SDA) at the Radioactive Waste Management Complex 

(RWMC) have been sources of contaminants in groundwater 

(table 1).

The presence of contaminants in the ESRP aquifer (fig. 2) 

has led to public concern about the quality of water in the 

aquifer and about how contaminated groundwater might affect 

the region and its economy. The DOE needs to understand 

thoroughly the movement and fate of these contaminants in 

the subsurface to minimize health risks and to plan effectively 

for any necessary remediation. To meet these needs, the 

U.S. Geological Survey (USGS) developed computer-based 

numerical models to simulate the movement of groundwater 

and the advective transport of contaminants in the aquifer 

under steady-state and transient flow conditions.
Introduction 3

ID19-0164_GWflow_fig. 1

EASTERN

SNAKE RIVER 

PLAIN

Craters

of the

Moon

National

Monument

BITTERROOT

 RANGE

LOST RIVER RANGE

LEMHI RANGE

WHITE KNOB MOUNTAINS

PIONEER MOUNTAINS

BUTTE

BINGHAM

CUSTER

BLAINE

CLARK

JEFFERSON

FREMONT

BONNEVILLE

POWER

LINCOLN MINIDOKA

LEMHI

Craters

of the

Moon

National

Monument

Mud Lake

Camas

Creek

Lost

River

Little

Lost

Birch

Creek

Mackay

Reservoir

Big

River

Snake River

Big Lost River

spreading areas

A, B, C, and D

Big Lost River

Sinks and 

Playas

93

93

20

20

33

33

22

22 28

26

26

Atomic

City

Howe

Arco

Mud

Lake

Terreton

East

Butte

Middle

Butte

Big Southern

Butte

USGS 87

USGS 23

MTR TEST

USGS 12

USGS

30

USGS 11

USGS 14

HIGHWAY 1

USGS 9

USGS 25

ARBOR

 TEST

WO2

Corehole 1

INEL 1

USGS 40,41

CPP 3

Site 17

USGS 4

USGS 2

USGS 6

USGS 18

USGS 21

USGS

27

USGS 8

SITE 2

13132520

13132500

13127000

13132513

13132515

13132535

13132565

USGS streamflow gaging station and number

Monitoring well and number

Idaho National Laboratory boundary

Model area

Eastern Snake River Plain

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.

USGS 11

13132500

EXPLANATION

TAN

RTC

INTEC (CPP3)

NRF

MFC

CFA

RWMC

Site facilities

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering 

Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

113° 00 ́

113°45 ́

113°30 ́ 112°30 ́ 112° 00 ́

43°

15 

44°

00 ́

44°

15 ́

0 10 20 Miles

0 10 20 Kilometers

IDAHO

BOISE

EASTERN 

SNAKE RIVER

PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

43°

30 

43°

45’

15

15

Figure 1. Location of the Idaho National Laboratory, the model area, selected facilities, wells, boreholes, streamflowgaging stations, and Craters of the Moon National Monument, Idaho.
4 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table 1. Summary of surface and subsurface wastewater disposal at selected facilities, Idaho National 

Laboratory, Idaho.

[Estimated disposal quantities: Estimated disposal quantities for Reactor Technology Complex, Test Reactor Area, and 

Idaho Nuclear Technology and Engineering Center from French and others, 1999. Estimated disposal quantities for the 

Radioactive Waste Management Complex from Mann and Knobel, 1987 and Becker and others, 1998. Contaminant 

concentrations: from Mann and Beasley, 1994; Bukowski and others, 1998; and Bartholomay and others, 2000. 

Abbreviations: MCLs, U.S. Environmental Protection Agency maximum contaminant levels for drinking water; Ci, curies; 

Mgal, million gallons; 137Cs, cesium-137; 3H, tritium; 90Sr, strontium-90; TCE, trichloroethene; PCE, tetrachloroethene; 

DCE, cis- and trans-1,2-dichloroethene; Cr, chromium, 129I, iodine-129; CCl4, carbon tetrachloride]

Facility Disposal site Years of 

disposal

Estimated 

disposal 

quantities

Contaminants with 

concentrations that 

have exceeded 

MCLs in groundwater

Test Area North Well, pond 1953 to 1993 61 Ci

717 Mgal

137Cs, 3H, 90Sr, TCE, 

PCE, DCE

Reactor Technology Complex Well, ponds 1952 to 1998 53,879 Ci

5,180 Mgal

3H, Cr

Idaho Nuclear Technology and 

Engineering Center

Well, ponds 1952 to 1998 22,254 Ci

19,165 Mgal

3H, 90Sr, 129I

Radioactive Waste Management 

Complex

Excavation pits, 

trenches

1952 to 1970 1,532,600 Ci

0.09 Mgal

CCl4

Groundwater flow and contaminant transport in the 

aquifer beneath the INL were simulated by Robertson 

(1974), and then evaluated and resimulated by Goode and 

Konikow (1990a, b). The calibrated numerical flow-transport 

and advective-transport models described in this report 

build on the work of earlier models, substantially more 

information than was available to earlier investigators, and 

a refined conceptual model of flow (Ackerman and others, 

2006) beneath the INL and vicinity that implies downward 

movement and deeper circulation of contaminants that migrate 

offsite of the INL. New information available for developing 

these models includes improved understanding of the 

hydrogeology beneath the INL and of the amount and timing 

of transient recharge to the aquifer beneath the INL, including 

a near record amount of streamflow infiltration from the Big 

Lost River in 1983 and 1984, and a period with little or no 

infiltration between 1987 and 1994. Additionally, more than 

30 years of water-level data for numerical-model calibration 

and measurements of contaminant concentrations in the 

aquifer are available.

Purpose and Scope

This report presents the results of simulations and 

analyses of three-dimensional (3-D) steady-state and transient 

groundwater flow models of the ESRP aquifer beneath the 

INL and vicinity. These models can be used to simulate 

contaminant movement in the aquifer to (1) determine 

long‐term risks associated with contaminants that are in the

aquifer currently or might be in the future from additional, 

slow releases of residual contamination in the unsaturated 

zone or from wastes that are left buried in shallow pits 

and trenches; (2) identify the best locations for monitoring 

contaminant movement in the aquifer; (3) evaluate the effect 

of future groundwater usage at the INL on water availability 

in the ESRP aquifer; and (4) evaluate risks to the aquifer 

associated with the operation of future nuclear research 

facilities.

The steady-state and transient flow models were 

constructed using the USGS modular, three-dimensional, 

finite-difference groundwater flow model, MODFLOW-2000 

(Harbaugh and others, 2000). Steady-state flow was simulated 

to represent conditions in 1980 with average streamflow 

infiltration from 1966–80 for the Big Lost River, which is the 

main variable inflow to the system. The transient flow model 

simulates groundwater flow that occurred between 1980 and 

1995, a period that included a 5-year wet cycle (1982–86) 

followed by an 8-year dry cycle (1987–94). Development 

of the numerical models involved (1) formulation and 

evaluation of various spatial and temporal discretization 

schemata; (2) specification of boundary and initial conditions; 

(3) weighting of calibration heads and head differences; 

(4) calibration; (5) specification of convergence and 

mass‐balance criteria; (6) sensitivity analyses for evaluation

of various conceptual assumptions, approximations, and 

simplifications; and (7) particle-tracking simulations to 

visualize 3-D flow and to assess model-derived groundwater 

flow paths, travel times, velocities, and source areas for 

consistency with other independent lines of evidence.
Introduction 5

ID19-0164_GWflow_fig. 2

BITTERROOT

 RANGE

LOST RIVER RANGE

LEMHI RANGE

EASTERN

SNAKE RIVER 

PLAIN

WHITE KNOB MOUNTAINS

PIONEER MOUNTAINS

Craters

of the

Moon

National

Monument

Mud Lake

Camas

Creek

Lost

River

Little

Lost

Birch

Mackay

Reservoir

Big

River

Creek

Snake River

Big Lost River

spreading areas

A, B, C, and D

Big Lost River

Sinks and 

Playas

Atomic

City

Howe

Arco

Mud

Lake

Terreton

East

Butte Middle

Butte

Big Southern

Butte

113° 00 ́

113°45 ́

113°30 ́ 112°30 ́ 112° 00 ́

43°

15 

44°

00 ́

44°

15 ́

0 10 20 Miles

0 10 20 Kilometers

IDAHO

BOISE

EASTERN 

SNAKE RIVER

PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

43°

30 

43°

45 

EXPLANATION

Plume of trichloroethene—Concentration greater 

than 5 micrograms per liter in 1997

Plume of strontium-90—Concentration greater 

than 2 picocuries per liter in 1998

Plume of tritium—Concentration greater than 

500 picocuries per liter in 1998

Idaho National Laboratory boundary

Model area

Eastern Snake River Plain boundary

Regional groundwater flowline

Well—Water contains chlorine-36 in 1992 from 

waste disposal 

Well—Water contains background concentration 

of chlorine-36

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.

Direction of regional groundwater flow

Trichloroethene

Tritium

Strontium-90

Chemical data from Beasley, 1995; Bukowski and others, 1998; and 

Bartholomay and others, 2000. 

TAN

RTC INTEC (CPP 3)

NRF

MFC

RWMC

CFA

Site facilities

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering 

Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Figure 2. Locations of documented contaminant plumes in the eastern Snake River Plain aquifer that exceed or have 

exceeded maximum contaminant levels for drinking water as defined by the U.S. Environmental Protection Agency, Idaho 

National Laboratory and vicinity, Idaho. Contaminant concentrations exceeding maximum contaminant levels for drinking 

water are summarized in table 1.
6 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Models were calibrated by adjusting aquifer properties 

to match simulated and observed heads or head differences 

by using an inverse modeling approach. The “trial-and‐error”

calibration approach initially was used to calibrate the 

simplest versions of the steady-state model, primarily to 

test the overall soundness of the conceptual model and to 

select important design elements to include in subsequent 

models. Complex versions of the steady-state and transient 

flow models were calibrated using the inverse modeling 

capabilities of MODFLOW–2000 (Hill and others, 2000). 

Optimized estimates of aquifer properties were calculated 

using a non-linear statistical regression procedure that adjusts 

aquifer properties to minimize differences between simulated 

and observed heads or head differences. Various summary, 

regression, and inferential statistics, in addition to comparisons 

of model-derived properties to measured properties, were 

used to evaluate the rationality of the model‐derived aquifer

properties. 

The steady-state flow model was used to estimate 

hydraulic conductivity and to evaluate groundwater flow 

paths, travel times, and velocities under flow conditions 

during 1980. The transient flow model was used to estimate 

specific yield and to evaluate groundwater flow paths, travel 

times, and velocities, and to simulate advective transport for 

variable flow conditions between 1980 and 1995. Because of 

scaling considerations, data availability, and computational 

constraints, these model-derived properties represent 

regional-scale estimates of aquifer properties that approximate 

the integrated effects of many smaller-scale features and 

processes.

Particle-tracking simulations using MODPATH, 

the USGS particle-tracking post-processing program for 

MODFLOW–2000 (Pollock, 1994), were used to produce 

maps of 3-D flow in the aquifer. MODPATH also was used 

to evaluate (1) how simulated groundwater flow paths and 

travel times differ between the steady-state and transient 

flow models, (2) how wet- and dry-climate cycles affect 

groundwater flow paths and travel times, (3) how episodic 

streamflow infiltration affects advective transport, and (4) how 

well the simulated groundwater flow directions and average 

linear velocities represent actual conditions in that part of the 

aquifer most affected by contamination.

Additional information on individual wells, boreholes, 

and streamflow-gaging stations used in this study are found 

in appendix tables A1 and A2. Additional maps showing the 

locations of these sites are in appendix B.

Description of Model Area

The model area is within the ESRP, a relatively flat 

topographic depression about 200-mi long and 50- to 70-mi 

wide surrounded by mountains on three sides and rimmed 

by the Snake River near the edges of its eastern and southern 

boundaries and by canyons as deep as 550-ft along and near 

its southwestern boundary. The altitude of the plain rises 

from about 2,900 ft near King Hill in the southwest to more 

than 6,200 ft near the southwestern extent of the Yellowstone 

Plateau in the northeast (fig. 3). Mountains surrounding the 

plain reach altitudes of 12,000 ft. The surface of the plain is 

primarily composed of loess and olivine basalt with many 

visually prominent volcanic landforms, such as cinder and 

lava cones, shield volcanoes, and rhyolite domes that rise as 

much as 2,500 ft above the plain (Lindholm, 1996, p. 5). 

The model area (fig. 3), in the west-central part of the 

ESRP, covers 1,940 mi2, extends 35 mi from northwest to 

southeast and 75 mi from northeast to southwest, and includes 

most of the INL (890 mi2). The model area is bounded on 

the northwest by mountain fronts and valleys tributary to the 

plain and on the southeast by an inferred regional groundwater 

flowline near the central axis of the ESRP (figs. 2 and 3). 

The northeast boundary is defined by a steep increase in 

the hydraulic gradient of the water table upgradient of the 

northeastern boundary of the INL and the Mud Lake area 

(fig. 3). The southwest boundary is defined by a northwest to 

southeast gridline from the USGS Regional Aquifer System 

Analysis (RASA) model of the ESRP aquifer (Garabedian, 

1992). This gridline is about 25 mi downgradient of the 

southwestern extent of measured concentrations of INLderived contaminants in the aquifer (fig. 2) (Beasley, 1995, 

appendix 2) and was selected as the boundary to ensure that 

the model area for this study would be sufficiently large to 

simulate contaminant movement beyond the farthest known 

extent of INL-derived contaminants in the aquifer. The vertical 

dimension of the model area is represented by the thickness of 

the aquifer, which is estimated to range from less than 600 ft 

to more than 3,000 ft.

The small farming and ranching communities of Arco, 

Howe, Mud Lake, Terreton, and Atomic City are near the 

northwestern, northeastern, and southeastern boundaries of 

the model area (fig. 2). Populations of these communities 

range from 25 to slightly more than 1,000. The Craters of the 

Moon National Monument (fig. 1) is a remote and largely 

undeveloped 83-mi2 area near the southwestern extent of the 

model area.

Hydrogeologic Setting

The climate in the model area is semiarid. Mean annual 

precipitation at the INL is about 0.7 ft (Goodell, 1988, fig. 5; 

Clawson and others, 1989, tables D-1 and D-2). About 0.1 

to 0.3 ft of snow accumulates at the INL during winter, and 

peak streamflow from snowmelt and runoff from the adjacent 

mountains typically occurs in late spring and early summer. 

Between 1950 and 1988, the mean annual air temperature at 

the Central Facilities Area (CFA; fig. 2) was 30oF; the coldest 

and warmest mean monthly temperatures were measured in 

January and during July–August, respectively (Clawson and 

others, 1989, table B-3).
Introduction 7

Figure 3. Direction of regional groundwater flow, discharge areas, and irrigated acreage, eastern Snake River Plain, 

Idaho.

ID19-0164_GWflow_fig. 3

Mud

Lake

Snake River

4100

4100

4000

4000

3800

4200

4300

4400

4600

4800

5000

5400

5800

6000

6200

4700

4500

4200

3000

Thousand

Springs

Area

Yellowstone

Plateau

40 Miles

0 20

0 20

40 Kilometers

IDAHO

BOISE

EASTERN 

SNAKE RIVER IDAHO PLAIN NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

114°30' 114°00' 113°30' 113°00' 112°30' 112°00' 111°30'

115°00'

44°

00'

43°

30'

43°

00'

42°

30'

42°

00'

King

Hill

MODEL

AREA

EXPLANATION

4000

Idaho National Laboratory boundary

Regional groundwater flowline, 1980 (Ackerman, 1995)

Model area

Eastern Snake River Plain

Water-table contours—Shows altitude of water table in 

1980. Contour intervals 50, 100, and 200 feet. Some 

contours approximately located (modified from 

Lindholm and others, 1988. Vertical datum is National 

Geodetic Vertical Datum of 1929 (NGVD 29).

Irrigated acreage, 1992 (DeWayne McAndrew, U.S. Bureau 

of Reclamation, written commun., 1996)

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.
8 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Groundwater in the ESRP aquifer flows to the southwest 

and discharges primarily through large springs and seeps 

along the Snake River in the Thousand Springs area along the 

southwestern margin of the ESRP (fig. 3). Recharge to the 

ESRP aquifer is from infiltration of surface water diverted 

for irrigation, underflow from tributary drainages, stream and 

canal losses, and infiltration of precipitation (Garabedian, 

1992, p. 11, table 15). Land that is irrigated with groundwater 

on the ESRP is along the southeastern and southern margins of 

the plain, from north of Idaho Falls to west of Twin Falls, and 

in the Mud Lake area northeast of the INL (fig. 3). In 1980, 

about 1,760,000 acre-ft of water was withdrawn from about 

4,000 wells across the plain to irrigate about 930,000 acres 

(Garabedian, 1992, p. 19-21).

Surface-water flow onto the INL and vicinity is 

intermittent, and nearly all streamflow infiltrates through the 

thick unsaturated zone and recharges the ESRP aquifer. Depth 

to the water table ranges from 200 ft in the northern part of the 

model area to 1,000 ft in the southern part. Streams tributary 

to the ESRP near the INL originate in mountain ranges north 

and west of the model area and include the Big Lost River, 

the Little Lost River, Birch Creek, and Camas Creek (fig. 1). 

The Big Lost River, on the west-central side of the ESRP, is 

the most significant surface-water feature in the model area. 

The Big Lost River drainage basin drains an area of about 

1,410 mi2 upstream of the USGS streamflow-gaging station 

(13132500) near Arco (fig. 1). Water from the river is stored 

in Mackay Reservoir (capacity 44,370 acre-ft, Bennett, 1990) 

about 40 mi upstream of the INL (fig. 1). In most years, 

much of the water in the river downstream of the reservoir 

is diverted for irrigation or infiltrates through the riverbed 

before reaching Arco. To prevent flooding of downstream 

facilities, a large percentage of the flow from the Big Lost 

River downstream of Arco is diverted to a series of four 

interconnected spreading basins near the southwest boundary 

of the INL (fig. 1). During years with sufficient precipitation, 

the Big Lost River flows onto the broad, undulating ESRP near 

Arco and terminates in the Big Lost River Sinks and a series 

of three interconnected playas east of Howe (fig. 1).

Previous Investigations

The most comprehensive study of the ESRP aquifer was 

completed as part of the USGS Regional Aquifer System 

Analysis (RASA) program. In that study, Whitehead (1986, 

1992), Lindholm and others (1988), and Lindholm (1996) 

described the regional hydrogeologic framework, hydrologic 

properties, and geologic controls on groundwater movement. 

Kjelstrom (1986, 1995) described streamflow gains and losses, 

and compiled regional groundwater budgets. Garabedian 

(1986, 1992) synthesized hydrologic data and constructed a 

regional groundwater flow model of the entire ESRP aquifer 

(10,800 mi2). These studies provided the regional context for 

constructing the groundwater flow models described in this 

report.

Anderson and Liszewski (1997) combined information 

from geophysical logs (table A1; Anderson, Ackerman, 

and others, 1996), rock cores, and outcrops to describe the 

stratigraphy of the unsaturated zone and aquifer beneath 

the INL and vicinity. The work of Anderson and Liszewski 

(1997) provides the basis for defining the hydrogeologic 

units used in the groundwater flow models described in 

this report. Ackerman (1991) and Anderson and others 

(1999) described the distribution of hydraulic properties 

in the ESRP aquifer and the geologic features controlling 

that distribution. Bennett (1990) estimated the amount, 

distribution, and timing of recharge to the ESRP aquifer at 

the INL from streamflow infiltration in the Big Lost River. 

Previous groundwater models also provided information 

used to construct the conceptual and numerical flow models. 

Spinazola (1994) simulated groundwater flow in the Mud 

Lake area upgradient of the INL. Ackerman (1995) developed 

an advective-transport model of regional groundwater flow 

based on the groundwater flow model of the ESRP aquifer by 

Garabedian (1992). McCarthy and others (1995) developed 

a groundwater flow model for the area of the INL to support 

groundwater remediation for specific INL facilities. Several 

INL facility-scale models also were developed to support risk 

assessments for remedial investigation feasibility studies, 

including coupled unsaturated- and saturated-zone flow and 

transport models for TAN (Schaffer-Perini, 1993) and the SDA 

(Magnuson and Sondrup, 1998).

The current modeling effort also builds on the 

groundwater flow and contaminant transport modeling results 

of Robertson (1974) and Goode and Konikow (1990b). 

Robertson (1974) simulated two-dimensional steady-state 

and transient groundwater flow and contaminant transport. 

Robertson’s steady-state model, with no recharge from 

the Big Lost River, successfully reproduced the unusually 

wide contaminant plumes in the upper 200 ft of the aquifer; 

however, a larger transverse (αT = 450 ft) than longitudinal 

(αL= 300 ft) dispersivity was used. The αL to αT ratio derived 

from Robertson’s steady-state model, 0.67, is smaller than the 

ratios of 24 other published pairs of αL and αT, which ranged 

from 1 to 53 with a mean of 8.8 (Gelhar and others, 1992, 

table 1). This small αL to αT ratio, and the large simulated 

values for αL and αT, indicated that the steady-state model 

of Robertson (1974) did not adequately represent some of 

the geologic and hydrologic features governing contaminant 

transport. Dispersivity values were not reported for the 

transient flow simulations.
Conceptual Model 9

Goode and Konikow (1990b) recognized that 

groundwater flow directions and velocities varied temporally 

in the shallow flow field, partly caused by recharge from the 

Big Lost River near contaminated groundwater at the INL, 

and that the large model-derived αT of Robertson (1974) could 

have accounted for the effects of these variations. If these 

transient variations in the flowfield are ignored or undefined, 

they can result in larger estimates for αT, and smaller αL to αT

ratios to account for advective transport caused by transient 

influences. Using the steady-state and transient flow models 

of Robertson (1974), but including the magnitude, timing, 

and spatial distribution of recharge from the Big Lost River, 

Goode and Konikow (1990b) evaluated the effect of transient 

groundwater flow at the INL on estimates of αL and αT. 

Although the simulations of Goode and Konikow (1990b) 

resulted in αT values that were smaller than values for αL, their 

results were inconclusive and they were unable to determine 

the effect that transient variations in the flowfield had on 

dispersivities.

Ackerman and others (2006) developed a conceptual 

model of groundwater flow and contaminant transport for the 

area simulated in this study. This conceptual model provides a 

qualitative description of groundwater flow, emphasizing those 

geologic and hydrologic features that most strongly affect 

contaminant movement in the aquifer, and forms the basis of 

the numerical models described in this report.

Conceptual Model

The conceptual model of Ackerman and others 

(2006), upon which the numerical models described in this 

report are based, is a simplified description of the aquifer 

system. The conceptual model includes (1) descriptions 

of the hydrogeologic framework and hydraulic properties 

of the media; (2) descriptions of the spatial and temporal 

characteristics of the model boundaries; (3) estimates of 

inflows, outflows, and fluxes across model boundaries; 

(4) descriptions of the approaches used to estimate the 

components of the steady-state water budget and an 

assessment of the uncertainties associated with those 

estimates; (5) descriptions of groundwater flow paths, flow 

velocities, and the possible effects of transient influences 

on groundwater flow directions; (6) descriptions of the 

stratigraphic, structural, and hydrologic controls on 

groundwater flow; and (7) an assessment of how groundwater 

flow may affect contaminant movement in the aquifer.

Primarily because of data limitations, scaling 

considerations, and computational constraints, the conceptual 

model relies on simplifications that involve the grouping 

of individual basalt flows and basalt-flow groups, temporal 

averaging of aquifer inflows and outflows, spatial averaging of 

inflows and outflows across model boundaries, and an implicit 

representation of flow through the unsaturated zone to the 

water-table boundary. These simplifications largely preclude 

simulating the effects of small-scale physical features, 

short-term hydrologic processes, and non-uniform (or uneven) 

distribution of inflows and outflows across model boundaries, 

but are appropriate for modeling the transport of conservative, 

nonreactive contaminants for geographically large areas. 

Data limitations included (1) uneven spatial distribution 

of wells and boreholes, areally and vertically (fig. 4), (2) 

sparse well and borehole coverage in areas remote from the 

main facilities on the INL (fig. 4), (3) scaling-compatibility 

issues involving the application of small-scale (laboratory) 

measurements to a large-scale study, (4) uncertainties arising 

from partial well and borehole penetrations and different well 

completions that complicate interpretations of water-level, 

water-chemistry, and hydraulic-conductivity measurements, 

and (5) discontinuous or nonexistent hydrologic records.

Most wells in the model area penetrate only the upper 

200 ft of the aquifer. Depths of 114 monitoring wells that were 

used to evaluate transmissivity and hydraulic conductivity 

range from 21 to 991 ft below the water table. Only 13 of 

these wells penetrate more than 300 ft of the aquifer, and the 

average penetration of all wells is 182 ft. These and other 

monitoring wells are completed as open holes or holes with 

one or more perforated intervals or wells screens.

Hydrogeologic Framework

The ESRP is underlain by a thick sequence of Tertiary 

and Quaternary volcanic rocks and sedimentary interbeds that 

may be more than 10,000 ft thick (Whitehead, 1992, pl. 3). 

Stratigraphic data from 10 deep boreholes indicate that the 

base of the aquifer in the western part of the INL ranges from 

815 to 1,710 ft below land surface and likely coincides with 

the top of a thick and widespread layer of clay, silt, sand, and 

altered basalt of Tertiary age (1.7 to 2.2 Ma) (Anderson and 

Liszewski, 1997, p. 11). Surface-based electrical-resistivity 

surveys and drillhole data (fig. 4A) indicate the aquifer base in 

the model area ranges from about 700 to 4,800 ft below land 

surface and the thickness of the aquifer may exceed 2,500 ft 

in the eastern half of the INL and 4,000 ft in the southeastern 

part of the model area (Whitehead, 1986, sheet 2; 1992, pl. 6; 

Ackerman and others, 2006, p. 25 and fig. 14). 

Quaternary basalt flows make up about 85 percent of 

the unsaturated zone and aquifer; sediments, andesite flows, 

and rhyolite domes of Quaternary age make up the remaining 

15 percent. The database compiled by Anderson and Liszewski 

(1997) indicates that the unsaturated zone and aquifer are 

composed of at least 178 basalt-flow groups, 103 sedimentary 

interbeds, 6 andesite-flow groups, and 4 rhyolite domes. 

Stratigraphic units were combined by Anderson and Liszewski 

(1997, p. 14), based on similar age, into 14 composite 

stratigraphic units each made up of 5 to 90 stratigraphic 

subunits of similar age. Surficial mapping and correlation of 

subsurface stratigraphic units among numerous outcrops and 

geophysical logs and cores from 333 boreholes (fig. 4B) at and 

near the INL indicate that many of these stratigraphic units are 

continuous across large parts of the model area. 
10 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 4

IDAHO

BOISE

EASTERN 

SNAKE RIVER

PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake

Terreton LOST RIVER RANGE

LEMHI RANGE

WHITE KNOB

MOUNTAINS

PIONEER MOUNTAINS

Atomic

City

Howe

Arco

Mud

Lake

Terreton LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake

Terreton LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake

Terreton LOST RIVER RANGE

WHITE KNOB

MOUNTAINS

PIONEER MOUNTAINS

Mud

Lake

Camas

Cr

Birch

Creek

Mackay

Reservoir Mud

Lake

Camas

Cr

Lost

River

Little

Lost

Birch

Snake River

Creek

Big

River

Mackay

Reservoir

Mud

Lake

Camas

Cr

Lost

River

Little

Lost

Birch

Creek

Big

River

Mackay

Reservoir Mud

Lake

Camas

Cr

Lost

River

Little

Lost

Birch

Creek

Big

River

Mackay

Reservoir

Little Lost River

WHITE KNOB

MOUNTAINS

PIONEER MOUNTAINS

Lost

River

Big

WHITE KNOB

MOUNTAINS

PIONEER MOUNTAINS

Snake River

Snake River

Snake River

A. Base of the aquifer B. Basalt stratigraphy

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

44°

00'

43°

45'

43°

30'

43°

15'

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

44°

00'

43°

45'

43°

30'

43°

15'

0 10 20 Miles

0 10 20 Kilometers

C. Hydraulic properties of the media D. Altitudes of the water table

Model area

Well or borehole

EXPLANATION

Idaho National Laboratory boundary

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.

Figure 4. Locations of wells and boreholes used to define (A) base of the aquifer, (B) basalt stratigraphy, (C) hydraulic 

properties of the media, and (D) altitudes of the water table, Idaho National Laboratory and vicinity, Idaho. Additional well and 

borehole maps are in appendix B.
Conceptual Model 11

Hydrogeologic Units

In the conceptual model, the fractured basalts, interflow 

zones, and interbedded sediments of the ESRP aquifer are 

represented as an equivalent porous media with non-uniform 

properties, and are grouped into three primary hydrogeologic 

units (table 2 and fig. 5), each with different hydraulic 

properties (table 3). In this representation of the aquifer the 

small-scale heterogeneities and anisotropies of individual 

basalt flows, basalt flow groups, and interbedded sediments are 

not preserved, and the resulting hydraulic conductivity of each 

hydrogeologic unit reflects the aggregate lithology, thickness, 

and number of basalt flows, interflow zones, and sedimentary 

interbeds in each hydrogeologic unit (tables 2 and 3).

The three hydrogeologic units used to represent the 

complex basalt stratigraphy of the aquifer are referred 

to as (1) hydrogeologic unit 1, younger rocks that are 

440,000–650,000 years old, (2) hydrogeologic unit 2, 

younger rocks that are 650,000–800,000 years old, and 

(3) hydrogeologic unit 3, intermediate-age rocks that are 

800,000–1,800,000 years old (table 2). Younger rocks form 

the uppermost part of the aquifer in much of the model area 

and intermediate-age rocks make up the largest volume of the 

aquifer in the model area. Altered rocks that are older than 

about 1,800,000 years underlie the aquifer. Other rocks of 

hydrologic significance in the model area are rhyolite domes 

that penetrate the younger and intermediate-age rocks.

Hydrogeologic Unit 1 

Hydrogeologic unit 1 is composed of many thin, densely 

fractured basalt flows and interbedded sediment simulated 

as 0 to about 500 ft thick. Hydrogeologic unit 1 is present 

at the water table beneath most of the INL, but is absent in 

the aquifer in the northwestern and southwestern parts of the 

model area (fig. 5). 

 Results of single-well aquifer tests in 67 wells with 

perforated or open intervals only in hydrogeologic unit 1 

indicate that the hydraulic conductivity of these rocks ranges 

from about 0.01 to 24,000 ft/d (table 3). Almost two-thirds of 

these estimates are larger than 100 ft/d and about one-third 

are larger than 1,000 ft/d; the large values reflect the effects of 

numerous interconnected interflow zones associated with the 

many thin flows in this unit (table 3). Porosity measurements 

of 1,504 core samples from hydrogeologic unit 1 and the 

overlying unsaturated zone at and near the RWMC ranged 

from 0.01 to 0.43 with 90 percent of the reported values, 

representing densely fractured basalt, between 0.05 and 

0.27 (table 3). In the RASA transient model simulations, 

Garabedian (1992, p. 44-46) used an average specific yield 

of 0.05 for all types of basalt and intermediate composition 

volcanic rocks, such as rhyolite and andesite, and 0.20 for all 

types of sediment in the upper 200 ft of the regional aquifer 

system. Ackerman (1995, p. 10) used a calibrated effective 

porosity of 0.21 to simulate advective transport in the 

uppermost 200 ft of the ESRP aquifer.

Table 2. Composite unit stratigraphy used to define hydrogeologic units and older rocks, Idaho National Laboratory and vicinity, Idaho.

[Abbreviation: CU, composite unit; ft, foot; >, greater than]

Hydrogeologic unit or rock

Age

(thousands of 

years before 

present)

Composite unit stratigraphy

Composite 

unit 

designation

Thickness 

(ft)

Number of 

basalt flow 

groups

Number of 

andesite flow 

groups

Number of 

sediment 

interbeds

Number of 

penetrating 

boreholes 

Hydrogeologic unit 1—Younger 

rocks consisting of thin, densely 

fractured basalt and interbedded 

sediment

440–650 CU 4 0–482 9 4 11 172

CU 5 0–329 3 6 143

CU 6 0–347 5 8 118

Hydrogeologic unit 2—Younger 

rocks consisting of massive, 

less densely fractured basalt and 

interbedded sediment

650–800 CU 7 0–409 7 10 70

Hydrogeologic unit 3—

Intermediate-age rocks 

consisting of slightly altered 

fractured basalt and interbedded 

sediment

800–1,800 CU 8 to 14 0–4,031 41 1 26 86

Older rocks consisting of intensely 

altered fractured basalt, rhyolitic 

ash-flow tuffs, and interbedded 

sediment—underlies base of the 

aquifer

> 1,800 13
12 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 5A

A

B

C

Mud Lake

Camas

Creek

Lost

River

Little

Lost

Birch

Creek

Mackay

Reservoir

Big

River

WHITE KNOB MOUNTAINS

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

Snake River

Big Lost River

spreading areas

A, B, C, and D

Atomic

City

East

Butte

Middle

Butte

Howe

Arco

BITTERROOT

 RANGE

LOST RIVER RANGE

LEMHI RANGE

Mud

Lake

Terreton

Big Southern

Butte

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

113° 00 ́

113°45 ́

113°30 ́ 112°30 ́ 112° 00 ́

43°

15 

44°

00 ́

44°

15 ́

0 10 20 Miles

0 10 20 Kilometers

43°

30 

43°

45’

A.

A A' Trace of section 

 Hydrogeologic units at the water table

Model area boundary

1—Younger rocks consisting of densely fractured basalt and interbedded 

sediment

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment. 

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment

Silicic rocks—Includes rhyolite domes Big Southern Butte (A), Middle Butte 

(B), and East Butte (C). Small unnamed dome and Cedar Butte andesite 

not shown

Idaho National Laboratory boundary

EXPLANATION

Site facilities

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering 

Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

TAN

RTC

INTEC

NRF

RWMC

CFA

MFC

A

A'

Figure 5. Distribution of hydrogeologic units at the (A) water table and (B) cross section along line of section A–A’, Idaho 

National Laboratory and vicinity, Idaho. Trace of section is shown in figure 5A.
Conceptual Model 13

ID19-0164_GWflow_fig. 5B

Contact—Approximately located, queried where uncertain

Water table

EXPLANATION

Unsaturated zone

1—Younger rocks consisting of densely fractured basalt and 

interbedded sediment.

2—Younger rocks consisting of massive, less densely fractured 

basalt and interbedded sediment. Queried where uncertain.

3—Intermediate-age rocks consisting of slightly altered fractured 

basalt and sediment.

Older rocks

?

Vertical scale greatly exaggerated

 Hydrogeologic units

B.

Unsaturated zone

?

?

?

?

?

? Water table

A'

METERS

1,400

1,200

1,300

1,100

1,500

1,600

1,700

800

600

700

500

400

300 

900

1,000

5,000

5,500

FEET

4,000

2,000

1,000

3,000

4,500

2,500

1,500

3,500

A

ALTITUDE, ABOVE NGVD29

Older rocks

Older rocks

RWMC

RTC

TAN

INTEC

INL boundary

2 1

3

3

0 10 20 Miles

0 10 20 Kilometers

Site facilities

Idaho National Laboratory

Idaho Nuclear Technology and Engineering Center

Reactor Technology Complex

Radioactive Waste Management Complex

Test Area North

INL

INTEC

RWMC

RTC

TAN

Note: Trace of section is shown in figure 5A.

Base of aquifer

Figure 5.—Continued.
14 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Table 3. Ranges of hydraulic conductivities and porosities for hydrogeologic units and older rocks and summary statistics of basalt flow thickness within hydrogeologic units, Idaho National Laboratory and vicinity, Idaho.

[Hydraulic conductivity: Conductivities were estimated from aquifer tests in wells having perforated or open intervals only within the respective hydrogeologic unit or rock. Modified from Ackerman and others (2006, tables 2 and 3) and Perkins (2008, table 2). Abbreviations: ft, foot; ft/d, foot per day; NA, not applicable; w, well; c, core; 100s, hundreds; <, less than]

Hydrogeologic unit or rock

Number 

of basalt 

flows

Property and sample data

Basalt flow thickness (ft) Hydraulic conductivity (ft/d) Number of 

wells (w) 

or core 

samples (c)

Range or 

median 

porosity

Number 

of core 

samples Minimum Median Mean Maximum Smallest Geometric midpoint Largest

Hydrogeologic unit 1—Younger rocks consisting 

of thin, densely fractured basalt and interbedded sediment

1,095 2 18 20 54 0.01 15 24,000 67 (w) 0.05 to 0.27 >1,000

Hydrogeologic unit 2—Younger rocks consisting 

of massive, less densely fractured basalt and interbedded sediment

212 4 28 29 78 6.5 95 1,400 4 (w) 0.11 100s

Hydrogeologic unit 3— Intermediate-age rocks 

consisting of slightly altered fractured basalt and interbedded sediment

441 2 22 23 107 .32 88 24,000 14 (w) 0.05 to 0.08 20

Older rocks consisting of intensely altered fractured 

basalt, rhyolitic ash-flow tuffs, and interbedded sediment—underlies base of the aquifer

NA NA NA NA NA .002 .008 .03 1 (w) <0.09 to 0.19 19

Sediment NA NA NA NA NA 5.9 × 10-7 .038 240 97 (c) 0.35 to 0.63 51
Conceptual Model 15

Hydrogeologic Unit 2

Hydrogeologic unit 2 is composed of massive, less 

densely fractured basalt flows and interbedded sediment that 

are 0–409 ft thick and average 266 ft in the 15 boreholes that 

penetrate the full thickness of this unit in the model area. 

Hydrogeologic unit 2 includes one of the thickest and most 

extensive basalt flow groups (basalt flow group I as defined 

by Anderson and Liszewski, 1997) beneath the INL and is 

important for interpretations of contaminant movement in the 

aquifer. Basalt-flow group I and an overlying layer of clay 

and silt (designated as the H-I interbed) underlie all but the 

northern and extreme southeastern parts of the INL (Anderson 

and others, 1997, p. 19). Hydrogeologic unit 2 underlies 

most of the INL, intersects the water table south and west of 

the INL, and is absent in the aquifer in the northwestern and 

southwestern parts of the model area (fig. 5). 

The hydraulic conductivity and bulk porosity of 

hydrogeologic unit 2 generally are less than that of 

hydrogeologic unit 1 because of the thick, massive interiors 

and fewer interconnected interflow zones associated with 

the basalt flows of this unit (table 3). Hydraulic conductivity 

values range from 6.5 to 1,400 ft/d for single-well aquifer tests 

in four wells with perforated intervals only in hydrogeologic 

unit 2 (table 3). The porosity of the massive basalt of 

hydrogeologic unit 2 probably is within the lower end of the 

range estimated for porosity of the densely fractured basalt of 

hydrogeologic unit 1, 0.05 to 0.27. Knutson and others (1992, 

p. 4–21) reported a median porosity of 0.11 for hundreds 

of nonvesicular basalt cores from the unsaturated zone and 

aquifer at and near the RWMC (table 3), a value that may 

approximate the porosity of massive basalt because it does 

not include the effects of more vesicular basalts and interflow 

zones.

Hydrogeologic Unit 3

Hydrogeologic unit 3 is composed of slightly altered, 

fractured basalt and interbedded sediment and constitutes 

the full thickness of the aquifer in the northwestern and 

southwestern parts of the model area (fig. 5). Hydrogeologic 

unit 3 is simulated as 0–4,031 ft thick, and thickens 

substantially from west to east and from northeast to 

southwest in the model area (figs. 5B and 6B). The interpreted 

distribution of older rocks that underlie hydrogeologic unit 

3 and that form the base of the aquifer indicates changes of 

more than 2,000 ft in the saturated thickness of hydrogeologic 

unit 3 from northeast to southwest across the central part of 

the model area (fig. 5B) that may be related to differential 

subsidence and uplift.

Results of single-well aquifer tests in 14 wells with 

perforated or open intervals only in hydrogeologic unit 3 

indicate that the hydraulic conductivity ranges from about 

0.32 to 24,000 ft/d (table 3). However, a comparison of 

24 hydraulic conductivity estimates of hydrogeologic 

units 1 and 2 (undifferentiated) near the INTEC with 68 

hydraulic conductivity estimates of hydrogeologic unit 3 

near TAN indicate that the average hydraulic conductivity 

of hydrogeologic unit 3 near TAN is about 1 order of 

magnitude smaller than hydrogeologic units 1 and 2 near 

the INTEC (John Welhan, Idaho State Geological Survey, 

written commun., 1999). The porosity of hydrogeologic unit 3 

probably is within the lower end of the range of that estimated 

for the densely fractured basalt of hydrogeologic unit 1, 0.05 

to 0.27. Median values for 10 nonvesicular and 10 vesicular 

basalt cores at TAN were about 0.05 and 0.08, respectively 

(table 3; Allan Wylie, Idaho Water Resources Research 

Institute, written commun., 2000). Median values of porosity 

for hundreds of nonvesicular and vesicular basalt cores from 

hydrogeologic units 1 and 2 (undifferentiated) at and near the 

RWMC were 0.11 and 0.22, respectively (Knutson and others, 

1992, p. 4–21). Comparison of these porosity values indicates 

that porosities of hydrogeologic unit 3 may be smaller than 

porosities of hydrogeologic units 1 and 2.

Older Rocks that Underlie the 

Base of the Aquifer

The base of the aquifer is interpreted as the contact 

between hydrogeologic unit 3, which is present throughout 

most of the model area, or hydrogeologic unit 2 where unit 

3 is absent, and the underlying Tertiary-age rocks (fig. 5). 

This contact is characterized by an abrupt downward increase 

in altered basalt and interbedded sediment (Mann, 1986, 

p. 4–5; Whitehead, 1992, p. 10; Anderson and Liszewski, 

1997, p. 11; Morse and McCurry, 1997, p. 6–7). Based on 

electrical‐resistivity surveys (Whitehead, 1986, sheet 2), the

estimated altitude and depth to the base of the aquifer ranges 

from about 80 to 4,200 ft above NGVD of 1929 (fig. 6A) and 

from about 700 to 4,800 ft below land surface, respectively, 

resulting in an aquifer thickness that ranges from about 200 

to 4,000 ft (fig. 6B) (Ackerman, 2006, p. 25). Direct evidence 

indicating the location of the base of the aquifer was limited to 

data from 13 deep wells and boreholes (fig. 4A). In seven wells 

and coreholes this contact also coincides with an increase in 

the alteration of basalts, an abrupt increase in temperature 

gradient interpreted to represent a change from convectivedominated to conductive-dominated heat flow, and a decrease 

in hydraulic conductivity and porosity (Mann, 1986, p. 21; 

Morse and McCurry, 1997, p. 6–7; Welhan and Wylie, 1997, 

p. 99; Morse and McCurry, 2002, p. 222; Mazurek and others, 

2004). Collectively these factors indicate that water circulation 

is limited in the older rocks. 

Few estimates of hydraulic conductivity and porosity 

are available for these older rocks. Hydraulic conductivities 

ranging from 0.002 to 0.03 ft/d (table 3) were calculated from 

four aquifer tests (Mann, 1986, p. 21) in borehole INEL1, 

about 4 mi north of the INTEC (fig. 1). Porosity values range 

from less than 0.09 to 0.19 (table 3).
16 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 6A

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Big Lost River

Birch

Creek

Snake River

TAN

RTC

INTEC

RWMC

CFA

A.

MFC

NRF

Atomic

City

Howe

Arco

Mud

Lake Terreton

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

Model area boundary

EXPLANATION

81 to 900

901 to 1,800

1,801 to 2,600

2,601 to 3,500

3,501 to 4,238

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Altitude of base of the aquifer—in feet. Datum is 

National Geodetic Vertical Datum of 1929.

Big Lost River

Sinks and 

Playas

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.

Figure 6. Aquifer (A) altitude and (B) thickness as defined by borehole data and surface-based electrical-resistivity 

surveys, Idaho National Laboratory and vicinity, Idaho.
Conceptual Model 17

ID19-0164_GWflow_fig. 6B

200 to 700

701 to 1,200

1,201 to 2,000

2,001 to 3,000

3,001 to 4,031

Aquifer thickness—in feet

Big Lost River

spreading areas

A, B, C, and D

Big Lost River

Sinks and 

Playas

Birch

Creek

Snake River

TAN

RTC

INTEC

RWMC

CFA

MFC

Atomic

City

Howe

Arco

Mud

Lake Terreton

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

Model area boundary

EXPLANATION

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Little Lost River

Big Lost River

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.

NRF

B.

Figure 6.—Continued.
18 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Sediment Interbeds

Basalts in the model area are intebedded with sediment 

throughout the unsaturated zone, hydrogeologic units 1, 2, and 

3, and the underlying Tertiary rocks (fig. 7) and compose from 

less than 1 to 50 percent of the rocks penetrated by boreholes 

in the model area (fig. 4B). Four depositional processes 

contributed sediment to the area: (1) windblown deposits of 

clay, silt, and fine sand are present in thin deposits throughout 

most of the model area (Nace and others, 1975, p. 35; 

Anderson, Liszewski, and Ackerman, 1996, p. 3); (2) fluvial 

deposits of sandy gravel in stream channels and finer-grained 

clayey silt in terminal playas at the distal ends of river systems 

(Nace and others, 1975, p. 19–27; Gianniny and others, 1997, 

p. 31); (3) lacustrine deposits of thick clay and silty clay layers 

in and near Mud Lake (Stearns and others, 1939, p. 17, 39; 

Spinazola, 1994, p. 10); and (4) alluvial deposits along and 

near the mouths of tributary valleys and adjacent mountain 

fronts.

Sediment interbeds in the three hydrogeologic units are 

mostly fine grained, ranging from very fine sand to clay-sized 

(Perkins, 2008), and tend to reduce aquifer bulk hydraulic 

conductivity and increase bulk porosity. Laboratory hydraulic 

conductivity measurements from 97 core samples (primarily 

from the unsaturated zone at and near the RWMC and the 

INTEC), described as having a silt loam to gravely texture, 

ranged from 5.9 × 10-7 to 240 ft/d (table 3). Laboratory 

porosity measurements from these same core samples ranged 

from 0.35 to 0.63 (table 3). 

The amount of sediment penetrated by individual 

boreholes ranges from less than 5 percent of the stratigraphic 

column to more than 50 percent near the terminus of the 

Big Lost and Little Lost Rivers in an inferred depositional 

center known informally as the Big Lost Trough (Anderson, 

Ackerman, and others, 1996; Geslin and others, 1997; 

Gianniny and others, 1997). The boundaries of the Big Lost 

Trough in this report are expanded beyond that of Gianniny 

and others (1997, p. 31) to include the coalescing sedimentary 

deposits along and near the channel, floodplain, sinks, and 

playas of the Big Lost River, Little Lost River, Birch Creek, 

Camas Creek, and Mud Lake (fig. 7). Within the Big Lost 

Trough, sediments grade from fluvial, sandy gravel within 

stream channels to finer-grained clayey silt within terminal 

playas at the distal ends of the river systems that historically 

have drained into this structural depression. 

Two interpretations of the Big Lost Trough are shown 

in figure 7 to account for differences in methods, data, and 

interpolation techniques used to evaluate the distribution 

of sediment. One area, interpreted from borehole logs 

(Whitehead, 1992, pl. 5), shows where sediment was 

estimated to compose from 100 to 999 ft of the stratigraphic 

section (including older rocks) (fig. 7A). A second area, where 

sediment was estimated to constitute more than 11 percent 

of the stratigraphic section (excluding older rocks) (fig. 7B), 

was based on interpretations from the geologic map of the 

INL (Kuntz and others, 1994) and natural-gamma logs 

from wells drilled to depths of more than 300 ft below 

land surface (Anderson, Ackerman, and Liszewski, 1996; 

Anderson, Ackerman and others, 1996). Water-table contours, 

superimposed over this structural feature, show the relation 

between hydraulic gradients, flexures in water-table contours, 

and areas of abundant sediment accumulation defined by 

boreholes with greater than 11 percent sediment. 

Rhyolite Domes

Rhyolite domes (exposed as buttes) in the model area 

are clustered in two areas (fig. 5); three domes are near the 

southeast boundary of the model area—Middle Butte, East 

Butte, and an older unnamed dome of limited surficial extent 

between Middle Butte and East Butte not shown in figure 5

(Kuntz and others, 1994). The other rhyolite dome, Big 

Southern Butte is south of the INL boundary. Big Southern 

Butte is the largest of the four rhyolite domes. Rhyolite 

domes are uplifted, vertical plug-like masses, consisting of 

thick flows and blankets of rhyolite and other associated 

intermediate composition rocks such as andesite, that are 

interpreted to penetrate a large thickness of the younger rocks 

and intermediate-age rocks (Kuntz and Dalrymple, 1979, 

p. 30-34; Spear and King, 1982, p. 396-400; Kuntz and others, 

1994; Anderson and Liszewski, 1997; Hughes and others, 

1999, fig. 16; McCurry and others, 1999, p. 170-174).

Hydraulic properties of rhyolite domes have not been 

measured. Based on the general characteristics of these less 

vesicular rocks, however, water-table contours (Bartholomay 

and others, 1997, fig. 9), and temperature data from well 

Corehole 1 (fig. 1) that penetrates the saturated part of 

the unnamed dome between Middle Butte and East Butte, 

rhyolite domes probably have low permeability and may have 

hydraulic properties similar to those of the massive basalt 

of hydrogeologic unit 2. A temperature log of Corehole 1 

(Morse and McCurry, 2002, fig. 2) indicates that most of the 

unnamed dome is in hydraulic contact with the cold water of 

the aquifer. Inferred water-table contour deflections around the 

unamed dome and Middle and East Buttes (fig. 7); however, 

probably indicate that the hydraulic conductivity of these 

rocks is smaller than that of the adjacent fractured basalt, 

hydrogeologic unit 1. The lack of a similar deflection of 

contours near Big Southern Butte probably indicates that this 

dome is fractured at depth or may lie above the water table. If 

the hydraulic conductivity and porosity of the rhyolite domes 

are similar to that of the massive basalt of hydrogeologic unit 

2, then the conductivity probably ranges from about 6.5 to 

1,400 ft/d and porosity probably is within the lower end of 

the 0.05 to 0.27 range of porosity estimated for hydrogeologic 

unit 1 (table 3). In the RASA study, a value of 0.65 ft/d for 

hydraulic conductivity and a value of 0.05 for specific yield 

were used for silicic volcanic rocks (Garabedian, 1992, 

p. 44-46, tables 19 and 20).
Conceptual Model 19

Figure 7. Water-table contours and areas of abundant sediment in the model area, Idaho National Laboratory and vicinity, 

Idaho. Areas of abundant sediment were interpreted from (A) borehole logs and (B) geologic maps and natural-gamma logs.

ID19-0164_GWflow_fig. 7

A

B C

A

B C

0 10 20 Miles

0 10 20 Kilometers

Mud

Lake

Camas

Cr

Birch

Creek

Mackay

Reservoir Mud

Lake

Camas

Cr

Lost

River

Little

Lost

Birch

Creek

Big

River

Mackay

Reservoir

Big Lost River

Little Lost River

Snake River

Snake River

A

Sediment—Thickness estimated to compose from 

100 to 499 feet of the stratigraphic section

Sediment—Thickness estimated to compose from 

500 to 999 feet of the stratigraphic section

Silicic rocks—Includes rhyolite domes Big 

Southern Butte (A), Middle Butte (B), and East 

Butte (C). Small unnamed dome and Cedar Butte 

andesite not shown

Water-table contour—Shows altitude of water 

table in 1995. Intervals 10 and 100 feet. Some 

contours approximately located (Bartholomay 

and others, 1997) Vertical datum is NGVD 29. 

4400

Model Area boundary

EXPLANATION

Idaho National Laboratory boundary

A Silicic rocks—Includes rhyolite domes Big 

Southern Butte (A), Middle Butte (B), and East 

Butte (C). Small unnamed dome and Cedar Butte 

andesite not shown

Water-table contour—Shows altitude of water 

table in 1995. Intervals 10 and 100 feet. Some 

contours approximately located (Bartholomay 

and others, 1997) Vertical datum is NGVD 29. 

4400

Model Area boundary

EXPLANATION

Idaho National Laboratory boundary

Sediment—Thickness estimated to compose more 

than 11 percent of the stratigraphic section

IDAHO

BOISE

EASTERN 

SNAKE RIVER

PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

4600

4500

44504450

4400

4300

4200

4500

4400

4300

4200

4600

LEMHI RANGE

WHITE KNOB

MTNS

PIONEER MTNS

Atomic

City

Howe

Arco

Mud

Lake Terreton LOST RIVER RANGE

LEMHI RANGE

WHITE KNOB

MTNS

PIONEER MTNS

Atomic

City

Howe

Arco

Mud

Lake Terreton LOST RIVER RANGE

A. B.

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

44°

00'

43°

45'

43°

30'

43°

15'

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

Base from U.S. Geological Survey digital data, 1:24,000 and Modified from Whitehead, 1992, pl. 5.

1:100,000. Universal Transverse Mercator projection, Zone 12N; 

North American Datum of 1927.
20 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Volcanic Rift Zones, Vents, and Vent Corridors

Volcanic rift zones are areas of increased concentrations 

of volcanic activity on the ESRP. Vent corridors are narrow 

zones of aligned vents, dikes, and fissures in and near volcanic 

rift zones (Anderson and others, 1999; Ackerman and others, 

2006, fig. 7). Fissures and tension cracks associated with 

these features may provide local conduits for flow, and deepseated dikes that feed these fissures may impede groundwater 

flow. Although these structural features are identified in the 

conceptual model (Ackerman and others, 2006, p. 11), their 

effects on groundwater flow are largely unknown. These 

features may produce preferential flow; however, the available 

geochemical and hydrologic information do not provide 

evidence for preferential flow and therefore these features are 

not represented in the numerical models and are not discussed 

further.

Conceptual Model Boundaries and Fluxes

Three physical and three artificial boundaries define the 

model area. The physical boundaries are the water table, the 

northwest mountain-front, and the base of the aquifer (fig. 8). 

The artificial boundaries are the northeast regional-underflow, 

the southeast flowline, and the southwest regional-underflow 

(fig. 8). In the conceptual model, inflow to the aquifer occurs 

across the water table, northwest mountain-front, northeast 

regional-underflow, and base of the aquifer boundaries, and 

from waste-disposal injection wells operated in the past. 

Outflow occurs across the southwest regional-underflow 

boundary and from irrigation and industrial production 

wells. No flow is exchanged across the southeast boundary 

as a consequence of the boundaries definition as a flowline. 

Although the conceptual model characterizes the base of 

the aquifer as an inflow boundary, few data are available to 

characterize the direction, quantity, and distribution of flow 

across this boundary. 

Inflows and outflows across model boundaries are 

constant in a steady-state groundwater flow model, but vary 

in a transient groundwater flow model. In a steady-state 

model, the assumption is that the groundwater system is 

in approximate equilibrium. Inflows into the model area 

equal outflows resulting in no changes in aquifer storage. 

A transient groundwater flow model represents a dynamic 

system with changes in inflows, outflows, and aquifer storage. 

Both model types are presented in this report, thus inflows 

and outflows across boundaries are discussed in terms of a 

time‐averaged snapshot from 1980, and in terms of dynamic

fluxes between 1981 and 1995. More than 50 years of waterlevel observations in more than 100 wells (with variable 

lengths of record; fig. 4D) indicate that the aquifer is never 

truly at steady state, but the available data indicate that the 

steady-state assumption is most closely approximated by 

water-table conditions in 1980 (Ackerman and others, 2006, 

p. 36, table 6).

Inflows and outflows, in cubic feet per second, across 

model boundaries are summarized in a groundwater budget 

that was developed for the conceptual model for 1980 (fig. 9; 

table 4). The 157 ft3/s residual for the estimated budget was 

about 7 percent of inflow with inflows exceeding outflow. 

Budget uncertainty, using the 5-year (1976–80) stress 

period of the transient 3-D RASA flow model as a basis of 

comparison, was ±7 percent of the average value of the total 

inflow (2,394 ft3/s) and ±10 percent of the average value of 

the total outflow (2,316 ft3/s) for the RASA and conceptual 

model (Ackerman and others, 2006, p. 38). Differences in 

water-budget estimates between the conceptual model and the 

RASA models were attributed to (1) coarse discretization of 

time and space for the RASA model, (2) interpolation errors 

resulting from inflow and outflow estimates that are assumed 

to be uniformly distributed within the RASA model grid cells, 

(3) differences in hydrogeologic (or professional) judgment, 

and (4) differences in accounting methodology (Ackerman and 

others, 2006, p. 36).

Inflow Boundaries

Estimated inflow to the model area during 1980 was 

2,239 ft3/s (table 4). Of the inflow components for the 

conceptual model water budget, about 7 percent enters at the 

water table, about 4 percent is from change in storage, about 

2 percent is from upward flow across the base of the aquifer, 

and about 86 percent enters as underflow along the northwest 

mountain-front and northeast regional-underflow boundaries.

In the numerical models, inflow from storage is required 

to be zero for the steady-state model and varies temporally 

in the transient model. Like the conceptual model, underflow 

across the northwest mountain front between tributary valleys 

and flow across the southeast boundary were assumed to 

be zero. The underflow across the base of the aquifer from 

underlying rocks was treated as insignificant and assumed to 

be zero in the numerical models. 

Water-Table Boundary

The water-table boundary is represented by the contact 

between the unsaturated zone and saturated zone. Depth to 

the water table varies from 200 ft in the northern part of the 

model area to 1,000 ft in the southern part. The altitude of the 

water table decreases from about 4,600 ft near the northeast 

boundary to about 4,100 ft near the southwest boundary of the 

model area (fig. 9).
Conceptual Model 21

Figure 8. Location of the water table, northwest mountain-front, northeast regional-underflow, southwest regionalunderflow, southeast flowline, and base of the aquifer boundaries, Idaho National Laboratory and vicinity, Idaho.

ID19-0164_GWflow_fig. 8

WHITE KNOB MOUNTAINS

Mud Lake

Camas

Creek

Lost

River

Little

Lost

Birch

Creek

Mackay

Reservoir

Big

River

Snake River

Big Lost River

speading areas

A, B, C, and D

Atomic

City

Middle

Butte

East

Butte

Howe

Arco

BITTERROOT

 RANGE

LOST RIVER RANGE

LEMHI RANGE

Mud

Lake

Terreton

Big Southern

Butte Southeast

flowline

boundary

Southwest

regional-underflow

boundary

Northeast

regional-underflow

boundary

Northwest mountainfront boundary

Base of aquifer

113° 00 ́

113°45 ́

113°30 ́ 112°30 ́ 112° 00 ́

43°

15 

44°

00 ́

0 10 20 Miles

0 10 20 Kilometers

43°

30 

43°

45’

Horizontal scale same as map,

vertical scale greatly exaggerated

A'

METERS

1,400

1,200

1,300

1,100

1,500

1,600

1,700

800

600

700

500

400

300 

900

1,000

5,000

5,500

FEET

4,000

2,000

1,000

3,000

4,500

2,500

1,500

3,500

A

ALTITUDE, ABOVE NGVD29

Saturated zone

Older rocks

Water table

Northeast

boundary

Northeast

boundary

Southwest

boundary

Southwest

boundary

Unsaturated zone

CONCEPTUAL

MODEL

AREA

IDAHO

NATIONAL

LABORATORY

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

A.

B.

A

A'

TAN

RTC

INTEC

NRF

RWMC

CFA

MFC PIONEER MOUNTAINS

Craters

of the

Moon

National

Monument

Creek

Big Lost River

Sinks and 

Playas

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.
22 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Figure 9. Generalized 1980 groundwater budget components for the model area, Idaho National Laboratory and vicinity, 

Idaho.

ID19-0164_GWflow_fig. 9

EASTERN

SNAKE RIVER 

PLAIN

Craters

of the

Moon

National

Monument

BITTERROOT

 RANGE

LOST RIVER RANGE

LEMHI RANGE

Mud Lake

Camas

Creek

Lost

River

Little

Lost

Birch

Mackay

Reservoir

Big

River

Snake River

Big Lost River

speading areas

A, B, C, and D

Atomic

City

Howe

Arco

Mud

Lake Terreton

113° 00 ́

113°45 ́

113°30 ́ 112°30 ́ 112° 00 ́

43°

15 

44°

00 ́

44°

15 ́

0 10 20 Miles

0 10 20 Kilometers

IDAHO

BOISE

EASTERN 

SNAKE RIVER

PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

43°

30 

43°

45’

Water-table contour—Shows altitude of water table in March 

1980. Interval 50 feet. Dashed where approximately located. 

Datum is NGVD 29. Modified from Linholm and others, 1988.

Idaho National Laboratory boundary

Model area

Eastern Snake River Plain boundary

EXPLANATION

Site facilities

TAN

RTC

INTEC

NRF

MFC

RWMC

CFA

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Volumetric flux—Value is rounded to nearest 1 cubic foot 

per second. For the Big Lost River, the number above the 

arrow in red (95) represents streamflow-infiltration 

recharge, and the number below the arrow in dark red (367) 

represents underflow

4200

4250

4100

4150

4500

4550

4600

4650 4700

4750

4400

4500

4300

4350

4450

4200

95

Total groundwater

withdrawals

Precipitation

recharge

95

Irrigation

infiltration24

Flow across 

base of aquifer

44

Southeast

boundary

Industrial

wastewater

return

6

Southwest

boundary

Northeast

boundary

Northwest mountainfront boundary

Change

in storage

80

367

102

2,037

1,225

70

45

226

367

0

0

WHITE KNOB MOUNTAINS

PIONEER MOUNTAINS

Craters

of the

Moon

National

Monument

Creek

Big Lost River

Sinks and 

Playas

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.
Conceptual Model 23

Table 4. Summary of conceptual model boundary characteristics, estimated 1980 inflows and outflows, and water budget, 

Idaho National Laboratory and vicinity, Idaho.

[Steady-state model input values rounded to nearest tenth. Abbreviation: ft3/s, cubic foot per second; NA, not applicable; <, less than]

Inflow boundaries

Conceptual model Steady-state model input

Boundary characteristics

Flow

(ft3

/s)

Percentage 

of total

flow

Numerical

Spatial Temporal Spatial boundary 

characteristics

Flow

(ft3

/s)

Water-table boundary

Precipitation recharge Uniform Constant 70 3 Uniform 70.0

Streamflow infiltration

Big Lost River Nonuniform Variable 95 4 Nonuniform 1 125.3

Little Lost River Nonuniform Variable 0 0 Nonuniform 2 3.0

Birch Creek Nonuniform Variable 0 0 Nonuniform 3 20.0

Streamflow-infiltration subtotal 95 4 148.3

Irrigation infiltration Nonuniform Variable 24 1 Nonuniform 21.6

Industrial wastewater return Nonuniform Variable 6 <1 Nonuniform 5.9

Northwest mountain-front boundary Nonuniform Constant

Big Lost River underflow Uniform Constant 367 16 Nonuniform 4 361.0

Little Lost River underflow Uniform Constant 226 10 Nonuniform 5 223.0

Birch Creek underflow Uniform Constant 102 5 Nonuniform 6 62.0

Mountain-front underflow Nonuniform Constant 0 0 Uniform .0

Northwest mountain-front subtotal 695 646.0

Northeast regional-underflow boundary Nonuniform Constant 1,225 55 Nonuniform 1,225.0

Southeast-flowline boundary Uniform Constant 0 0 Uniform .0

Change in storage Uniform Variable 80 4 NA

Base of the aquifer Uniform Constant 44 2 Uniform .0

Total inflow 2,239 100 2,116.7

Outflow boundaries

Southwest regional-underflow boundary Nonuniform Variable 2,037 98 Nonuniform NA

Groundwater withdrawals

Irrigation Nonuniform Variable 37 2 Nonuniform 37.2

Industrial Nonuniform Variable 8 <1 Nonuniform 7.6

Total outflow 2,082 100

Budget residual 157

Percentage difference between inflow 

and outflow

7

1

 Mean annual discharge for 1966–80. 

2

 Simulated average flow. 

3

 Simulated diversion returns. 

4

 Basin yield minus mean annual discharge for 1966–90. 

5

 Basin yield minus simulated streamflow infiltration. 

6

 Basin yield minus diversion of streamflow outside the model area.
24 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

In the conceptual and steady-state models, flow through 

the unsaturated zone to the water table is treated implicitly as 

spatially nonuniform, time-averaged net infiltration recharge to 

the aquifer that is assumed to occur at a constant rate, whereas 

in the transient model, flow across the water table from some 

components varies in space and time. Components of the 

water budget that contribute water to the aquifer across the 

water-table boundary that are spatially uniform and temporally 

constant include precipitation recharge; spatially nonuniform 

and temporally (in the transient model) variable contributors 

include streamflow infiltration, and industrial wastewater 

and irrigation return flow. Typical unsaturated-zone flow 

processes such as moisture depletion from evaporation 

and evapotranspiration, downward percolation and lateral 

redistribution, alternate wetting and drying, and perching are 

not treated as distinct flow processes.

Precipitation Recharge

Precipitation recharge is characterized as spatially 

uniform and temporally constant in the steady-state and 

transient flow models (table 4). The effect of precipitation 

recharge in the model area has not been discernable in 

water‐level measurements. In areas where precipitation

accumulates as runoff into small, closed basins, numerous 

sedimentary interbeds in the thick unsaturated zone (more 

than 40 interbeds have been identified [Ackerman and others, 

2006, fig. 11]) intercept and laterally redistribute downward 

percolation (Nimmo and others, 2002). This redistribution 

tends to offset the effects of local runoff accumulation and 

probably maintains an approximately uniform and constant 

rate of recharge to the aquifer. Estimates of precipitation 

recharge range from 0.01 ft/yr (Cecil and others, 1992, p. 713) 

to as much as 0.08 ft/yr (Kjelstrom, 1995, p. 11). In the 

conceptual model water budget, 5 percent of the mean annual 

precipitation was used to establish a maximum recharge rate 

of 0.04 ft/yr. Volumetrically, precipitation recharge across the 

water-table boundary is 70 ft3/s and represents 3 percent of 

the total inflow estimate (table 4). When distributed across 

the model area, precipitation recharge represents a flux of 

0.04 (ft3/s)/mi2. This small areal flux indicates that the effect 

of precipitation recharge on groundwater flow directions and 

velocities is probably small.

Streamflow infiltration

In the conceptual steady-state model, streamflow 

infiltration is characterized as spatially nonuniform and 

temporally constant, and in the conceptual transient model 

as spatially nonuniform and temporally variable (table 4). 

Streamflow onto the INL is episodic and nearly all streamflow 

infiltrates through the thick, unsaturated zone and recharges 

the ESRP aquifer. Three streams potentially contribute 

infiltration to the water table—Big Lost River, Little Lost 

River, and Birch Creek—but only recharge from the Big 

Lost River is considered a significant source of infiltration 

(table 4; fig. 9). Estimates of recharge for the Big Lost River 

were based on measured discharge (fig. 10) and estimated 

infiltration rates in the Big Lost River Sinks, Playas, channel, 

and spreading areas (Bennett, 1990). Infiltration from the 

Little Lost River and Birch Creek is small because most 

streamflow either infiltrates or is diverted upstream of the 

INL boundary. Although flow from the Big Lost River also 

is diverted upstream of the INL boundary, during years with 

sufficient precipitation, flow from the Big Lost River enters 

the ESRP near Arco and terminates on the INL in a series of 

three interconnected playas southwest of TAN. From 1946 

to 2003, the annual mean discharge of the Big Lost River 

near Arco (streamflow-gaging station 13132500, fig. 10) was 

95.3 ft3/s (Brennan and others, 2005, p. 196).

Streamflow fluctuates greatly in response to short-term 

wet and dry climate cycles that typically last from 3 to 8 years. 

During dry climate cycles, streamflow in the Big Lost River 

near Arco frequently is zero. In 1983 and 1984, streamflow 

infiltration in the Big Lost River channel, spreading areas, 

sinks, and playas at the INL accounted for more than 

20 percent of the inflow component of the steady‐state

water budget and caused water-level rises exceeding 10 

ft locally (figs. 11 and 12). Flux across the water-table 

boundary from streamflow infiltration in the Big Lost River 

channel, spreading areas, sinks, and playas averaged about 

20 (ft3/s)/mi2 from 1966 through 1980 and was almost 

200 (ft3/s)/mi2 at the spreading areas in 1984. Streamflow 

infiltration fluxes are 2 and 3 orders of magnitude larger than 

flux from precipitation recharge. Because of its large flux and 

proximity to known sources and areas of contamination in 

the aquifer, streamflow infiltration from the Big Lost River 

is considered more important to understanding contaminant 

transport than the other components of inflow across the 

water-table boundary.

Streamflow infiltration was apportioned based on 

differences in measured discharge between upstream and 

downstream streamflow-gaging stations and allocated 

based on river mileage and surface area enclosed within the 

perimeter of each surface-water impoundment. The simulated 

distribution of streamflow infiltration is described in the 

Numerical Model section of this report under the heading 

Boundary Conditions.

Irrigation and Industrial Water Return Flows

Infiltration of agricultural irrigation water in the northern 

part of the study area, infiltration of landscape irrigation 

at facilities, and disposal of industrial waste to ponds and 

ditches at facilities at the INL were characterized as spatially 

nonuniform and temporally variable. Refined estimates of 

the boundaries and types of infiltration areas used for model 

simulations resulted in slightly different rates of irrigation 
Conceptual Model 25 Figure 10.

Annual mean discharge at streamflow-gaging stations on the Big Lost River, Idaho, for 1965–2002. (

A) Big Lost River below Mackay Reservoir near 

Mackay (13127000), (

B) Big Lost River near Arco (13132500), (

C) INL diversion at head near Arco (13132513), (

D) Big Lost River below INL diversion near Arco 

(13132520), (

E) Big Lost River at Lincoln Boulevard bridge near Atomic City (13132535), and (

F) Big Lost River above the Big Lost River Sinks near Howe (13132565). 

Locations of streamflow-gaging stations are shown in figure 1. Calendar year and water year discharge data for these six streamflow-gaging stations can be 

accessed at http://idaho.usgs.gov/. ID19-0164_GWflow_fig. 10

159

45

108

35

145

35

66

36

23

45

64

52

5

0

0

0

1

64

291

382

39

59

10

0

0

0

0

0

0

0

50

5

53

32

31

0

0

0

334

70

233

89

343

135

256

96

55

158

199

89

17

10

11

33

43

218

478

488

121

205

29

3

0

0

0

0

15

0

126

67

179

157

147

24

0

0

564

241

495

297

497

370

449

347

279

453

441

370

193

326

271

350

361

467

591

614

329

438

243

188

190

207

226

169

309

189

443

359

427

366

375

230

173

176

169

12

109

35

181

86

170

44

11

96

121

24

4

1

15

27

127

159

78

61

122

7

0

0

0

0

0

11

0

64

42

102

108

109

16

0

0

0

161

161

151

5

87

22

72

26

4

71

100

10

0

0

0

2

19

113

135

61

49

100

1

0

0

0

0

0

7

0

54

36

82

88

79

9

0

0

13

97

119

48

36

82

0

0

0

0

0

0

0

0

0

0

128

11

0

52

80

0

144

72

9

137

55

0

3

0

48

30

70

78

66

4

0

0

Estimated values

Average annual discharge for water years from 1946 to 2003 = 95.3 cubic feet per second1

Estimated values

A. 13127000 Big Lost River below Mackay Reservoir near Mackay B. 13132500–Big Lost River near ArcoC. 13132513–INL diversion at head near Arco D. 13132520–Big Lost River below INL diversion near ArcoE. 13132535–Big Lost River at Lincoln Boulevard bridge near Atomic City F. 13132565–Big Lost River above Big Lost River Sinks near Howe

Estimated values for 1965–84

Estimated values for 1965–84

Estimated values for 1965–84

Estimated values for 1965–96

0

500400300200100

1965

1970

1975

1980

1985

1990

1995

2000

0

700600500400300200100

Discharge, in cubic feet per second

1965

1970

1975

1980

1985

1990

1995

2000

0

200100

Years 1965-2002
26 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 11

ARBOR TEST

660

665

670

675

680

685

690

Depth to water, in feet below land surfaceDepth to water, in feet below land surface

4,475

4,480

4,485

4,490

4,495

4,500

USGS 9

590

595

600

605

610

615

620 4,410

4,415

4,420

4,425

4,430

4,435

4,440

USGS 12

305

310

315

320

Year Year

325

330

335

194819521956196019641968197219761980198419881992199620002004

4,485

4,490

4,495

4,500

4,505

4,510

USGS 25

255

260

265

270

275

280

285 1948

19521956196019641968197219761980198419881992199620002004

4,565

4,570

4,575

4,580

4,585

4,590

Altitude of water level, in feet above NGVD 29Altitude of water level, in feet above NGVD 29

Figure 11. Water levels in wells Arbor Test, USGS 12, USGS 9, and USGS 25 for 1948–2003, Idaho National Laboratory and 

vicinity, Idaho. Locations of wells are shown in figures 1 and 12.

infiltration than those given in the conceptual model (table 4). 

Irrigation infiltration rates were applied uniformly within 

individual irrigation areas and were simulated as constant 

but were applied only during the stress period representing 

the irrigation season, May through August of each year 

in the transient model. Infiltration rates of 2.55 × 10-8 and 

4.66 × 10-9 ft/s for surface-water and groundwater irrigation 

areas, respectively, were used and are equivalent to those of 

Spinazola (1994, p. 32-33, fig. 38).

Industrial wastewater return flows at the INL in 1980 

were 6 ft3/s, and included wastewater discharged in disposal 

ponds or ditches where it infiltrated into the unsaturated zone 

and the aquifer and into injection wells completed in the 

aquifer (table 4; fig. 9). The volume of wastewater discharged 

into infiltration ponds and wells varied over the years in 

response to the amount of industrial activity at INL facilities 

and changes in wastewater-disposal methods. Returns at the 

RTC and INTEC could have major short-term effects on 

contaminant migration because most contaminants in the 

aquifer beneath the INL originate at these two facilities and 

more than 50 percent of industrial wastewater returns were 

injected or infiltrated into the aquifer at these two facilities.

Water from Storage

In the conceptual model, releases of water from storage 

accounted for 4 percent of inflow in the 1980 water budget and 

were based on measured changes in water levels from October 

1979 to October 1980 and RASA derived storage coefficients 

ranging from 0.05 to 0.2 (Ackerman and others, 2006, p. 2). 

The net gain to the aquifer from a decrease in storage during 

this period was 80 ft3/s (table 4; fig. 9).

Water From Base of Aquifer

The conceptual-model water budget includes inflow of 

44 ft3/s across the base of the aquifer characterized as spatially 

uniform and temporally constant (Ackerman and others, 2006, 

p. 29). The steady-state and transient models, however, treat 

the base of the aquifer as a no flow boundary because this 

inflow estimate, based on data from a single 10,365-ft-deep 

corehole, INEL1 (fig. 1), and on the steepest vertical hydraulic 

gradients (0.071) as calculated by Mann (1986, table 2, p. 22), 

is small. Distribution of this inflow across the model area 

resulted in a flux of about 0.02 (ft3/s)/mi2, about one‐half

the flux estimate for precipitation recharge, 0.04 (ft3/s)/mi2. 
Conceptual Model 27

ID19-0164_GWflow_fig. 12

Base from U.S. Geological Survey digital data, 

1:24,000 and 1:100,000. Universal Transverse 

Mercator projection, Zone 12N; North American 

Datum of 1927.

Mud

Lake

Birch

Camas

Creek

Big

Lost

River

Little

Lost

River

Creek

Mud

Lake

Birch

Camas

Creek

Big

Lost

River

Little

Lost

River

Creek

Mud

Lake

Birch

Camas

Creek

Big

Lost

River

Little

Lost

River

Creek

Mud

Lake

Birch

Camas

Creek

Big

Lost

River

Little

Lost

River

Creek

113°00’ 113°45’

44°

00’

44°

45’

43°

30’

44°

00’

44°

45’

43°

30’

113°15’ 112°30’ 112°15’ 113°15’ 113°00’ 113°45’ 112°30’ 112°15’

BITTERROOT

RANGE LEMHI RANGE

LOST RIVER RANGE

East

Butte

Middle

Butte

Mud Terreton

Lake

Atomic

City

Howe

Arco

Big Southern

Butte

BITTERROOT

RANGE LEMHI RANGE

LOST RIVER RANGE

East

Butte

Middle

Butte

Mud Terreton

Lake

Atomic

City

Howe

Arco

Big Southern Butte

BITTERROOT

RANGE LEMHI RANGE

LOST RIVER RANGE

East

Butte

Middle

Butte

Mud Terreton

Lake

Atomic

City

Howe

Arco

Big Southern Butte

BITTERROOT

RANGE LEMHI RANGE

LOST RIVER RANGE

East

Butte

Middle

Butte

Mud Terreton

Lake

Atomic

City

Howe

Arco

Big Southern Butte

USGS 9

USGS 12

USGS 25

USGS 25

USGS 9

USGS

12

ARBOR

TEST

USGS 25

USGS 9

USGS

12

ARBOR

TEST

ARBOR

TEST

GENERALIZED WATER-LEVEL

RISE, JULY 1981 TO

JULY 1985

GENERALIZED WATER-LEVEL 

DECLINE, APRIL–AUGUST 1988 

TO APRIL–AUGUST 1991

GENERALIZED WATER-LEVEL 

DECLINE, MARCH–MAY 1991 

TO MARCH–MAY 1995

GENERALIZED WATER-LEVEL 

RISE, MARCH–MAY 1995 TO 

MARCH–MAY 1998

Modified from Pittman and others, 1988, fig. 10.

USGS 25

USGS

12

ARBOR

TEST

-6

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

I I I I I I I I

I I I I

I I

I I I I I

-8

-10

-8

10

8

10

4

2

2

4 6

6

6

4

4

2

-6

4

-4

-4

4

-6

4

4

8

6

6

USGS 9

Modified from Bartholomay and others, 1997, fig. 10.

Line of equal water-level change—Interval 2 feet. Negative value indicates water-level 

decline. Hachures indicate water-level change is less than the contour value.

USGS 9

I I I I 2

Modified from Bartholomay and others, 2000, fig. 10.

Modified from Bartholomay and others, 1995, fig. 10.

Conceptual Model Area

Well and identifier

0 10 20 MILES

0 10 20 KILOMETERS

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

EXPLANATION

Idaho National Laboratory boundary

A. B.

C. D.

Figure 12. Water-level changes for (A) July 1981 to July 1985, (B) April–August 1988 to April–August 1991, (C) March–May 1991 

to March–May 1995, and (D) March–May 1995 to March–May 1998, Idaho National Laboratory and vicinity, Idaho.
28 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Additionally, the location of this boundary is from several 

hundred to more than 1,000 ft beneath areas of known 

contamination in the aquifer and, because of this, inflow 

across this boundary probably has minimal influence on the 

advective movement of contaminants in the aquifer.

Northwest Mountain-Front Boundary

The northwest mountain-front boundary is defined by 

the edge of the mountain fronts of the Pioneer Mountains, 

Lost River Range, Lemhi Range, and Bitterroot Range and 

the mouths of the Big Lost River, Little Lost River, and Birch 

Creek valleys (fig. 9). In the conceptual steady-state and 

transient models, inflow across the northwest mountain‐front

boundary is represented as spatially nonuniform and 

temporally constant. Inflows across this boundary represent 

31 percent of the total inflow to the model area (table 4; 

fig. 9) and are limited to tributary valley underflow from the 

alluvial aquifers of the Big Lost River (367 ft3/s), Little Lost 

River (226 ft3/s), and Birch Creek (102 ft3/s). The amount 

of underflow from each stream valley is calculated as the 

basin yield minus simulated streamflow infiltration. Basin 

yield is defined as the annual mean water yield to the Snake 

River Plain from mountainous areas bordering the plain for 

water years 1934–80 (Kjelstrom, 1986, sheet 2) and includes 

groundwater underflow and surface-water flow onto the plain. 

Inflow across the intervening mountain fronts is assumed to 

be zero and these are treated as no-flow sections along the 

northwest mountain-front boundary (fig. 9). 

Water-table altitudes in the alluvial aquifers near the 

boundaries of the model area are several hundred feet above 

the altitude of the water table in the wells of the ESRP aquifer 

near the northwest boundary. These large differences in 

altitude indicate that underflow across the interface between 

the tributary valley alluvial aquifers and the ESRP aquifer 

probably is a combination of lateral flow and downward 

percolation in perched alluvial aquifers where these perched 

aquifers interfinger with basalt flows in the unsaturated zone 

of the ESRP aquifer and as lateral flow where the alluvial 

aquifer interfingers with basalt flows in the ESRP aquifer.

The estimated width of the aquifer at the mouth of the 

Big Lost River valley is 6.1 mi. The thickness of the alluvial 

aquifer in the Big Lost River valley at a well 4 mi northwest 

of Arco and near the mouth of the valley is as much as 760 ft 

(Crosthwaite and others, 1970, p. 73, fig. 25). Interbedded 

basalt and sediment at the mouth of the Big Lost River valley 

contain several vertically discrete water-bearing zones. The 

water table of the shallowest zone is 900 ft above that of the 

ESRP aquifer 6 mi south of Arco in well Weaver and Lowe 

(table A1; fig. B1). The less permeable parts of the sediment 

and basalt sequence probably cause some lateral movement 

of groundwater in perched aquifers to flow onto the Snake 

River Plain and percolate downward to recharge the aquifer 

(Crosthwaite and others, 1970, p. 71-75).

The width of the aquifer at the mouth of the Little Lost 

River valley was estimated at 5.7 mi. The thickness of the 

alluvial aquifer in the Little Lost River valley is at least 

312 ft about 12 mi northwest of Howe (fig. 1) (Mundorff 

and others, 1963, table 6), and may be thicker. Interbedded 

basalt and alluvium near the mouth of the Little Lost River 

valley may cause some groundwater to flow onto the plain as 

perched aquifers above the ESRP aquifer. Cascading water 

enters the casing in some wells near the mouth of the valley. 

The water table in the alluvium immediately east of Howe is 

nearly 200 ft higher than the water table in the ESRP aquifer 

only 1 mile to the south (Mundorff and others, 1963, p. 23) 

indicating that water levels in wells may stand at progressively 

lower levels as deeper aquifers are penetrated (Mundorff and 

others, 1963, p. 23-25). Most underflow from the Little Lost 

River valley is assumed to flow laterally at depth into the 

ESRP aquifer.

The width of the aquifer at the mouth of the Birch Creek 

valley was estimated at 5.2 mi. The thickness of the alluvial 

aquifer at the mouth of the Birch Creek valley is unknown, 

but based on the estimated thicknesses of the alluvial aquifers 

in the Big Lost River and the Little Lost River valleys, may 

be more than several hundred feet thick. The water table in 

the ESRP aquifer at well ANP 7, about 8 mi southeast of the 

northwest boundary and near the mouth of the Birch Creek 

valley, is at an altitude of about 4,580 ft. This water table 

is about 1,400 ft lower than the water table at the Wagoner 

Ranch well (table A1; fig. B2) about 11 mi upstream of where 

Birch Creek crosses the northwest model boundary. It is not 

known if a relatively uniform gradient is between wells ANP 

7 and Wagoner Ranch, or if a steep decrease in the water table 

is in the transition zone between the alluvial aquifer in Birch 

Creek valley and the ESRP aquifer similar to that observed 

near the mouths of the Big Lost River and Little Lost River 

valleys.

Underflow from the tributary valleys was apportioned and 

distributed on the basis of the estimated width and thickness of 

the alluvial aquifers and is described in the Numerical Model

section of this report under the heading Boundary Conditions.

Northeast Regional-Underflow Boundary

The northeast regional-underflow boundary coincides 

with a steep increase in the hydraulic gradient near the 

northeastern boundary of the INL (fig. 9). The hydraulic 

gradient along the trace of this boundary ranges from 27 to 

60 ft/mi, averages about 36 ft/mi, and reflects changes in 

aquifer transmissivity where basalt interfingers with less 

permeable sediments. Inflow across this 500–800 ft thick 

boundary was estimated at 1,225 ft3/s by applying Darcy’s 

Law, a hydraulic conductivity of 140 ft/d (a small value to 

reflect the presence of the less permeable sediments), an 

average hydraulic gradient of 36 ft/mi, a boundary length of 

35 mi, and a saturated thickness of 600 ft (Ackerman and 
Conceptual Model 29

others, 2006, p. 35). This inflow estimate represents 55 percent 

of the total inflow to the model area (table 4) and is in close 

agreement with the value of 1,207 ft3/s derived from the 

RASA model. In the conceptual steady-state and transient 

models, underflow along the northeast regional-underflow 

boundary is represented as spatially nonuniform and 

temporally constant. Underflow across the northeast boundary 

was distributed on the basis of estimated variations in the 

thickness and hydraulic conductivity of the aquifer along the 

northeast boundary and is described in the Numerical Model

section of this report under the heading Boundary Conditions.

Outflow Boundaries

Total outflow from the model area is 2,082 ft3/s (table 4). 

This estimate is 18 percent (469 ft3/s) less than that derived 

from the RASA model (2,551 ft3/s), and 7 percent (157 ft3/s) 

less than the conceptual-model inflow estimate (table 4). Of 

the outflow components, about 98 percent is underflow across 

the southwest boundary to adjacent parts of the aquifer and 

about 2 percent is from groundwater withdrawals for irrigation 

and industrial water use.

Southwest Regional-Underflow Boundary

In the steady-state and transient models, outflow across 

the southwest boundary is represented as spatially nonuniform 

and in the transient model as temporally variable. The length 

and shape of this boundary are not well documented. Surfacebased electrical-resistivity surveys (Whitehead, 1986, sheet 2) 

indicate that the aquifer thickness along this boundary ranges 

from about 500 to 3,000 ft (fig. 6B). The variable flow across 

this boundary reflects the character of large, episodic inflows 

from Big Lost River streamflow infiltration. Head definition 

for the southwest boundary of the aquifer was limited to 

water-level measurements from six wells that are from 3 to 

10 mi from the southwest boundary (fig. 4D); consequently, 

outflow estimates across this boundary perhaps are the least 

reliable of all the water-budget estimates. Outflow across the 

southwest boundary was estimated at 2,037 ft3/s (table 4; 

fig. 9) using Darcy’s Law and data described in Ackerman and 

others (2006, p. 35), and is similar to the value, 2,000 ft3/s, 

summed for underflow across this boundary from the flow-net 

analyses by Mundorff and others (1964, pl. 4).

Groundwater Withdrawals

In the steady-state and transient models, groundwater 

withdrawals from the aquifer are industrial withdrawals at 

onsite facilities and irrigation withdrawals for use offsite 

(fig. 9), and are represented as spatially nonuniform and, in 

the transient model, temporally variable. For the steady-state 

and transient models, irrigation withdrawals are constant, but 

are applied seasonally in the transient model. Groundwater 

withdrawals in the model area in 1980 were estimated to be 

45 ft3/s (Ackerman and others, 2006, p. 34 and table 6). Slight 

differences in subtotals for well withdrawals between the 

conceptual and numerical models are due to refined estimates 

of irrigation and industrial withdrawals. Local effects of 

industrial withdrawals were not expected to have long-term 

effects on aquifer response beneath the central part of the INL; 

however, withdrawals and returns at the RTC and INTEC 

could have major short-term effects on contaminant migration 

because most contaminants in the aquifer beneath the INL 

originate at these two facilities. These facilities also account 

for more than 50 percent of industrial groundwater withdrawal 

at the INL. Groundwater used for irrigation in the model area 

is withdrawn from the aquifer primarily near Mud Lake, but 

smaller quantities also are withdrawn near Howe (Ackerman 

and others, 2006, p. 34).

No-Flow Boundaries

In the steady-state and transient flow models, the base 

of the aquifer and the southeast flowline boundaries are 

designated as no-flow boundaries (fig. 9). The boundary 

at the base of the aquifer has been described as an inflow 

boundary conceptually, but treated as a no-flow boundary in 

the numerical models. 

The southeast-flowline boundary, near the central axis 

of the ESRP, is represented by a southwest-trending flowline, 

projected vertically through the thickness of the aquifer 

(800–4,000 ft) (fig. 6B), and consequently flow across this 

boundary, conceptualized as spatially uniform and temporally 

constant, is presumed to be zero. Water-table maps constructed 

for the ESRP aquifer for 1928–30, 1956–58, and 1980 (Stearns 

and others, 1938; Mundorff and others, 1964; and Lindholm 

and others, 1988) indicate that changes in water levels along 

and east of the southeast boundary are spatially uniform. 

Consequently, flow directions along most of the southeast 

boundary of the model area are relatively stable, and flowlines 

constructed for this area are assumed to be temporally constant 

(Ackerman and others, 2006, p. 35). 

Conceptualization of Groundwater Flow and 

Contaminant Transport 

Water-table contours indicate that the subregional and 

regional directions of groundwater flow in the model area 

are from northeast to southwest (fig. 13A). The volume of 

groundwater flow increases progressively in a direction 

downgradient of the northeast boundary. This increased flow 

is the result of tributary-valley underflows along the northwest 

mountain-front boundary (695 ft3/s), precipitation, irrigation, 

industrial wastewater, and streamflow infiltration across the 

water-table boundary (195 ft3/s). Together these additions 

account for about 44 percent of the outflow across the 

southwest boundary; the remainder of the outflow originates 

from underflow along the northeast boundary (1,225 ft3/s).
30 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 13A

A

B

C

Mud Lake

Camas

Creek

Lost

River

Little

Lost

Birch

Creek

Mackay

Reservoir

Big

River

Snake River

Big Lost River

spreading areas

A, B, C, and D

Atomic

City

East

Butte

Middle

Butte

Howe

Arco

BITTERROOT

 RANGE

LOST RIVER RANGE

LEMHI RANGE

Mud

Lake

Terreton

Big Southern

Butte

4450

4500

Water-table contour—Shows altitude of water table 

in March 1980. Interval 50 feet. Dashed where 

approximately located. Datum is NGVD 29. 

Modified from Linholm and others, 1988.

4200

4250

4100

4150

4500

4550

4600

4650 4700

4750

4400

4500

4300

4350

4450

4200

4550

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

113° 00 ́

113°45 ́

113°30 ́ 112°30 ́ 112° 00 ́

43°

15 

44°

00 ́

44°

15 ́

0 10 20 MILES

0 10 20 KILOMETERS

43°

30 

43°

45’

A.

Generalized flowpath—Arrow in direction of flow

A A' Trace of section 

 Hydrogeologic units at the water table

Model area boundary

1—Younger rocks consisting of densely fractured basalt and interbedded 

sediment

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment 

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment

Silicic rocks—Includes rhyolite domes Big Southern Butte (A), Middle Butte 

(B), and East Butte (C). Small unnamed dome and Cedar Butte andesite 

not shown

Idaho National Laboratory boundary

EXPLANATION

Site facilities

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering 

Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

A

A'

TAN

RTC

INTEC

NRF

RWMC

CFA

MFC

WHITE KNOB MOUNTAINS

PIONEER MOUNTAINS

Creek

Big Lost River

Sinks and 

Playas

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.

Figure 13. Distribution of hydrogeologic units and direction of groundwater flow (A) at the water table and water-table 

contours for 1980, and (B) along the line of section (A–A’), Idaho National Laboratory and vicinity, Idaho. Trace of section 

shown in figure 13A.
Conceptual Model 31

ID19-0164_GWflow_fig. 13B

Contact—Approximately located, queried where uncertain

Water table

Generalized line of equal head potential

Generalized flowpath—Arrow in direction of flow

EXPLANATION

Unsaturated zone

1—Younger rocks consisting of densely fractured basalt and interbedded 

sediment.

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment. Queried where uncertain.

3—Intermediate-age rocks consisting of slightly altered fractured basalt 

and sediment.

Older rocks

?

Vertical scale greatly exaggerated

Note: Trace of section is shown in figure 13A.

 Hydrogeologic units

Unsaturated zone

?

?

?

?

?

? Water table

A'

METERS

1,400

1,200

1,300

1,100

1,500

1,600

1,700

800

600

700

500

400

300 

900

1,000

5,000

5,500

FEET

4,000

2,000

1,000

3,000

4,500

2,500

1,500

3,500

A

B.ALTITUDE, ABOVE NGVD29

Older rocks

Older rocks

RWMC

Big Lost River underflow

RTC

Little Lost River underflow

Big Lost River Sinks and Playas

TAN

INTEC

Birch Creek underflow

INL Boundary

2 1 2

3

3

3

0 10 20 MILES

0 10 20 KILOMETERS

 INL Idaho National Laboratory

INTEC Idaho Nuclear Technology and Engineering Center

 RTC Reactor Technology Complex

RWMC Radioactive Waste Management Complex

 TAN Test Area North

Site facilities

Base of aquifer

Northeast

boundary

Southwest

boundary

Figure 13.—Continued.
32 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

A semi-quantitative distribution of groundwater flow 

along a northeast to southwest cross section (A–A’, fig. 13B) 

through the central part of the model area (Ackerman and 

others, p. 48), indicates that head decreases and then increases 

with depth as the aquifer thickens and thins in a direction 

downgradient of the northeast boundary. Downward flow 

is indicated in areas where head decreases with depth and 

upward flow is indicated in areas where head increases with 

depth. The largest changes in vertical gradient are depicted 

as occurring southwest of the INL; just upgradient of where 

the younger, more conductive rocks of hydrogeologic unit 1 

pinch out and hydrogeologic unit 2 intersects the water table 

(fig. 13B). This depiction also indicates that flow is dominantly 

horizontal, but shows slight downward movement of water 

(note vertical exaggeration in fig. 13B) from the younger rocks 

into the rocks of intermediate age at this location and implies 

downward movement and deeper circulation of contaminants 

that migrate offsite. 

The conceptual model implies that most contaminant 

movement beneath the INL takes place in the interflow 

zones and thin, densely fractured, and highly conductive 

basalts and interbedded sediments of hydrogeologic unit 

1, which compose most of the upper 200 ft of the aquifer 

beneath most of the INL. This hypothesis is consistent with 

conclusions reached by earlier investigators who noted that 

“...waste plumes generally remain as relatively thin lenses 

in about the upper 250 ft of the aquifer” (Robertson, 1974, 

p. 6). The hypothesis was based on (1) long-term observation 

of water levels and contaminant movement in the aquifer, 

(2) estimates of inflows and outflows across the boundaries 

of the model area, (3) current interpretations of the 3-D 

geometry and the distribution of hydrogeologic units within 

the aquifer, (4) location of contaminant sources in the model 

area, (5) estimates of the hydraulic properties of the aquifer, 

(6) history of waste-disposal practices at the INL, and (7) a 

simplified 2-D model of groundwater flow (Ackerman 

and others, 2006, p. 48-49) that depicts the effects of the 

hydrogeologic framework on groundwater flow along a 

northeast to southeast section through the central part of the 

model area. The most important implications of the conceptual 

model for contaminant transport are:

• Preferential flow along basalt interflow zones, which 

implies a large horizontal to vertical anisotropy.

• Restricted downward movement of water and 

contaminants from hydrogeologic unit 1 into 

and across the less conductive massive basalts of 

hydrogeologic unit 2 beneath and near contaminant 

source areas (RTC, INTEC, and RWMC).

• Enhanced dispersion and dilution of contaminants in 

the aquifer resulting from the spatial and temporal 

variability of streamflow infiltration from the Big 

Lost River in close proximity to areas of known 

contamination in the aquifer.

• Inferred downward movement and deeper circulation 

of water and contaminants beginning near the southern 

boundary of the INL and downgradient of known 

locations of contaminants in the aquifer.

Numerical Model

The development of the numerical model was based 

on the conceptual groundwater flow model of the system 

and involved (1) selecting the governing equation(s) of 

groundwater flow constituting the mathematical model and 

the computer program to solve the mathematical model 

numerically; (2) translating the conceptual model to a form 

suitable for numerical modeling including determining 

the system geometry, discretizing the spatial and temporal 

domains—designing a spatial grid, selecting time steps 

and stress periods, and formulating boundary conditions; 

and (3) selecting measurements of physical properties and 

hydrologic measurements of aquifer state such as water 

levels in wells—heads and flow to and from the aquifer. The 

conceptual model and available data were integrated into 

the numerical model which was subsequently calibrated, 

whereby model parameters and boundary conditions were 

adjusted based on an objective criterion of the match between 

simulated and observed heads and flows.

Groundwater flow was simulated with MODFLOW-2000, 

a computer program that simulates three-dimensional 

groundwater flow through a porous medium using a numerical 

finite-difference method for solving the governing equations 

for steady (time invariant) and transient (time variable) 

flow (Harbaugh and others, 2000, p. 1). MODFLOW-2000 

was selected because it (1) simulates 3-D saturated flow, 

(2) is compatible with other particle tracking and solute 

transport computer codes that are readily available, (3) is 

capable of calculating accurate sensitivities (Hill and others, 

2000, p. 3), (4) has been widely used by the groundwater 

scientific community for more than 30 years, (5) is thoroughly 

documented, and (6) has program developers who were 

readily accessible for consultation. MODFLOW-2000 is 

constrained by its governing flow equations to (1) flow 

of a uniform density and viscosity fluid through saturated 

porous media and (2) aquifers where the principal axes of the 

hydraulic conductivity tensor are aligned with the orthogonal 

model coordinates. The current model is assumed to meet 

these constraints because (1) water in the aquifer is fresh water 

within a narrow range of temperature and, therefore, any small 

fluid-density and viscosity variations are negligible, (2) flow 

through the fractured parts of the aquifer can be represented as 

flow through an equivalent porous medium, (3) hydrogeologic 

units constituting the aquifer are sub-horizontal (not steeply 

dipping) and, therefore, vertical hydraulic conductivity can be 

simulated perpendicular to the nearly horizontal hydrogeologic 

units, and (4) large scale horizontal anisotropy in the basalt 

aquifer is not indicated. 
Numerical Model 33

Model Discretization

The finite-difference method used by MODFLOW-2000 

requires that the continuous simulated domain be replaced by 

a discretized domain. Spatial discretization is defined in terms 

of layers, rows, and columns that result in discrete rectilinear 

volumes called cells. This three-dimensional array of cells is 

known as the model grid. For transient models, time must also 

be divided into discrete intervals called stress periods and time 

steps. Stress periods represent intervals over which specified 

flows in and out of the aquifer are constant. Flows can change 

from one stress period to the next. Stress periods consist of 

one or more time steps where simulated heads and flows are 

calculated for each cell.

The flow models of the INL and vicinity were designed 

for use in contaminant transport modeling at a subregional 

scale. The model grid was created in a study-specific 

Albers equal-area projection and was rotated 31.0605° 

counterclockwise about the origin of 43° 34′ 35.25" N. 

113° 50′ 32.63" W., such that it is oriented parallel to the 

dominant direction of flow (fig. 14); the orientation also 

minimized the size of the model grid. The projection used 

the North American Datum of 1927, a central meridian of 

113° W., standard parallels of 42° 50′ N. and 44° 10′ N., 

a false easting of 656,166.67 ft (200,000 meters), and 

the latitude of the projection’s origin was 41° 30′ N. The 

southwest boundary of the model grid was coincident with a 

gridline between columns 22 and 23 of the RASA model grid 

(Garabedian, 1992, p. 38). The coincidence of the study area 

and the model grid with the RASA model grid was used to 

facilitate comparison and analysis of the groundwater budget 

for the conceptual model (Ackerman and others, 2006, p. 36, 

fig. 17) and analysis of simulated fluxes within sub areas of 

the model.

Spatial Discretization

Spatial discretization of the model domain was 

determined by considering suitable representation of 

(1) hydrogeologic units that extend over hundreds of mi2; 

(2) the flat, nearly uniform, hydraulic gradient across the INL; 

and (3) the large areal extent of contaminant plumes (fig. 2) in 

the southwest part of the INL (for example, in 1998 the plume 

of tritium for concentrations greater than 500 picocuries/liter 

(pCi/L) encompassed an area of about 43 mi2). Uniform model 

grid spacing was used because (1) most groundwater transport 

models compatible with MODFLOW-2000 require uniform 

grids over the transport simulation domain, and (2) numerical 

accuracy is better for regular grids (Anderson and Woessner, 

1992, p. 64). Two uniform horizontal model grid spacings 

were used in the steady-state and transient flow models: (1) a 

coarse grid spacing of 0.5 by 0.5 mi (0.25 mi2 per model 

cell) used in early models and (2) a fine grid spacing of 0.25 

by 0.25 mi (0.0625 mi2 per model cell) (fig. 14) used for the 

calibrated models described in this report. Even finer model 

grid spacing might be necessary for a site-scale model of 

contaminant transport, but was not considered necessary for 

suitably representing the features described above. 

The vertical discretization of the model was referenced to 

the altitude of the 1980 water table (fig. 13), in that the bottom 

of model layer 1 (the top of layer 2) was specified 100 ft below 

the 1980 water-table surface (fig. 15). The vertical model grid 

spacing consisted of six layers of varying thickness:

• Layers 1 approximately 100 ft thick, varying with the 

water-table altitude,

• Layer 2, 100 ft thick,

• Layer 3, 0 to 100 ft thick,

• Layer 4, 0 to 200 ft thick,

• Layer 5, 0 to 300 ft thick, and

• Layer 6, 0 to 3,229 ft thick (fig. 15).

Model layers 1, 2, and 3 were kept relatively thin in order 

to more accurately represent flow in hydrogeologic units 1 and 

2, the units that compose most of the upper part of the aquifer 

beneath the INL (fig. 15) and that contain contaminant plumes. 

Because the mean thicknesses of basalt flows in hydrogeologic 

units 1, 2, and 3 are 20, 29, and 23 ft, respectively (table 3), 

a layer thickness of 100 ft ensured that each of the model 

layers included several basalt interflow zones. Model layers 

3–6 contained the base of the aquifer in some locations and 

consequently were absent or less than full thickness at those 

locations.

The model domain is 80 mi northeast to southwest, 

44 mi northwest to southeast, and greater than 4,000 ft thick 

(figs. 14 and 15). The model grid used for the calibrated 

models described in this report discretizes this volume into 

176 rows, 320 columns, and 6 layers to generate 337,920 cells, 

of which 168,737 were active and 169,183 were inactive 

(fig. 14). Inactive cells are cells outside the simulated volume 

but inside the model grid because the irregular model shape 

does not conform to the rectilinear finite-difference model 

grid. A coarse model grid, with cells 0.5 by 0.5 mi in the areal 

dimension also was used in this study, and discretizes this 

volume into 88 rows, 160 columns, and 6 layers to generate 

84,480 cells, of which 42,230 were active and 42,250 were 

inactive (fig. 14). Vertical discretization was the same for both 

grids.
34 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 14

BITTERROOT

 RANGE

LOST RIVER RANGE

LEMHI RANGE

WHITE KNOB MOUNTAINS

PIONEER MTNS

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.

Mud

Lake

Camas

Creek

Lost

River

Little

Lost

Birch

Creek

Mackay

Reservoir

Big

River

Snake River

Rows

0

80

160

Columns

0

80

160

240

320

Atomic

City

Howe

Arco

Mud

Lake

Terreton

EXPLANATION

Site facilities

Idaho National Laboratory boundary

Model area boundary

Cell (showing size and orientation of half-mile grid 

for comparison)

Cell (showing size and orientation of quarter-mile grid; 

not all cell boundaries shown)

Inactive cells

Active cells

Head-dependent flow cells

Specified flow cells

River cells

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Material and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Southeast

boundary

Southwest

boundary

Northeast

boundary

Northwest mountain- front boundary

TAN

RTC

INTEC

NRF

RWMC

CFA

MFC

113°30 ́ 113° 00 ́ 112°30 ́ 112° 00 ́

43°

30 

44°

00 ́

44°

15 ́

0 10 20 MILES

0 10 20 KILOMETERS

43°

45'

43°

15'

114° 00 ́

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Figure 14. Model domain and locations of head-dependent, specified flow, and river boundary conditions for layer 1 used for 

0.5- and 0.25-mile model grids for models of groundwater flow, Idaho National Laboratory and vicinity, Idaho.
Numerical Model 35

ID19-0164_GWflow_fig. 15

EXPLANATION

Unsaturated zone

1—Younger rocks consisting of densely fractured basalt and interbedded 

sediment.

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment. Queried where uncertain.

3—Intermediate-age rocks consisting of slightly altered fractured basalt 

and sediment.

Older rocks

Contact—Approximately located, queried

where uncertain

Water table

?

Vertical scale greatly exaggerated

Note: Trace of section is shown in figure 13A.

 Hydrogeologic units

Layer 1 Layer 2 Layer 3

Layer 4

Layer 5

Layer 6

Layer number boundary Layer 3

 INL Idaho National Laboratory

INTEC Idaho Nuclear Technology and Engineering Center

 RWMC Radioactive Waste Management Complex

 TAN Test Area North

Site facilities

Base of aquifer

Southwest

boundary

Northeast

boundary

Water table Unsaturated zone

METERS

1,400

1,200

1,300

1,100

1,500

1,600

1,700

800

600

700

500

400

300 

900

1,000

5,000

5,500

FEET

4,000

2,000

1,000

3,000

4,500

2,500

1,500

3,500

A

ALTITUDE, ABOVE NGVD29

Older rocks

Older rocks

RWMC

TAN

INTEC

INL boundary

2 1 2

3

3

3

0 10 20 MILES

0 10 20 KILOMETERS

A'

? ?

? ?

?

?

Figure 15. Vertical discretization and distribution of the model layers and hydrogeologic units for models of 

groundwater flow, Idaho National Laboratory and vicinity, Idaho. Trace of section shown in figure 5A.
36 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Temporal Discretization

Aquifer inflows and outflows in the model area vary 

due to (1) long-term, decadal changes in climate and water 

use, (2) short-term (3–8 years) wet or dry climate cycles, 

and (3) annual or seasonal changes in streamflow and water 

use. The transient flow model simulates the hydrologic 

conditions of the aquifer from 1980 through 1995, such that 

simulations do not capture decadal changes, but do capture 

a wet (1982–86) and a dry (1987–94) climate cycle and 

also annual and seasonal hydrologic cycles. The periods 

1983–84 and 1987–94 produced the maximum discharge and 

the longest dry period, respectively, in the Big Lost River 

during the past 60 years (fig. 10). Unless otherwise stated, all 

references to years in this report are for calendar years January 

through December.

Temporal discretization is guided by the timing and 

duration of simulated stresses. Streamflow infiltration and 

irrigation water use in the model area generally is between 

May and August (fig. 16; Spinazola, 1994, fig. 31). In the 

northeast part of the model area seasonal changes in water 

levels of 2–3 ft were observed (fig. 17) in wells such as 

USGS 27 (fig. 1) in response to groundwater withdrawals for 

irrigation, with water levels rising from September through 

April and falling from May through August. Changes in 

Figure 16. Monthly mean discharge at streamflowgaging station Big Lost River near Arco for water years 

1946 through 2006.

Figure 17. Stress periods and water levels at wells MTR TEST and USGS 27, 1981 through 1983, Idaho National Laboratory, 

Idaho.

ID19-0164_GWflow_fig. 16 Monthly mean discharge, in cubic feet per second

0

100

50

150

200

250

J F M A M J J A S O N D

Big Lost River near Arco (13132500)

0

2

4

6

8

10

Jan.-Apr. May-Aug. Sept.-Dec. Jan.-Apr. May-Aug. Sept.-Dec. Jan.-Apr. May-Aug. Sept.-Dec.

1981 1982 1983

Altitude of water level, in feet above arbitrary datum

SP 2 SP 3 SP 4 SP 5 SP 6 SP 7 SP 8 SP 9 SP 10

WELL USGS 27

WELL MTR TEST

SP 2 Stress period number

specified flows into or out of the active part of the model 

grid were represented with three seasonal (January–April, 

May–August, September–December) stress periods during 

each year. The transient model consisted of one annual 

steady‐state stress period representing 1980 followed by

45 seasonal stress periods representing 1981 through 1995.
Numerical Model 37

Boundary Conditions

Boundary conditions in the flow model specify the 

locations and characteristics of groundwater flow into and out 

of the active areas of the model grid (fig. 9). Specified flows 

into the active model grid occur at the northeast boundary, 

the northwest mountain-front boundary, and the water-table 

boundary (figs. 14 and 15). Within the model grid, specified 

inflows occur at injection wells and specified outflows occur at 

industrial or irrigation wells. These flows represent historical 

conditions for various boundaries and time intervals between 

1946 and 1995. No flow conditions occur at the southeast 

boundary, a stream surface, and the base of the aquifer. 

Head-dependent outflow conditions define the southwest 

boundary (fig. 14). The movement of water in and out of the 

model grid was simulated with various packages available in 

MODFLOW-2000 (Harbaugh and others, 2000) selected for 

their applicability to physical and hydrologic conditions at 

the boundary and to aid in accounting for water budget terms. 

McDonald and Harbaugh (1988) document the concepts of 

most packages used in the model. 

Water-Table Boundary

Inflow across the water table is from precipitation, 

streamflow infiltration, and return flows of irrigation and 

industrial water. These flows are characterized in the transient 

models as temporally variable specified flows, except for 

precipitation, which is characterized as constant specified flow. 

All specified flows are constant in the steady-state model.

Precipitation Recharge

Recharge from infiltration of precipitation was 

simulated across the water-table boundary and was applied 

throughout the model area using the Recharge Package from 

MODFLOW-2000. Precipitation recharge was allocated 

to model layer 1 cells at an areally uniform constant rate 

of 0.04 (ft3/s)/mi2. Precipitation recharge was simulated as 

constant because it composes a small proportion of the water 

budget; most of the changes in water levels are related to 

precipitation in the tributary basins rather than to precipitation 

on the plain.

Streamflow Infiltration

Streamflow infiltration from the Big Lost River, Little 

Lost River, and Birch Creek was simulated as specified flow 

using the River Package from MODFLOW-2000. Infiltration 

was allocated to layer 1 cells proportionately to the length of 

the trace of river channels or to the areas of cells occupied 

by the Big Lost River Sinks, Playas, and spreading areas 

(fig. 14). Amounts of infiltration were assigned to reaches of 

river channels and individual areas. In the steady-state model, 

differences in discharge between upstream and downstream 

gaging stations and measured outflows at gaging stations 

immediately upstream of surface-water impoundments were 

assumed to represent infiltration. In the transient model 

representing the period 1980–95, these infiltration estimates 

were reduced to account for evaporation losses. The periods 

for averaging streamflow infiltration are different and the level 

of detail for discussion and implementation of streamflow 

infiltration are greater for the numerical model than for the 

conceptual model. 

Streamflow estimates for the Big Lost River are based 

on measured daily mean discharges or when data were not 

available, on estimates using partial records, miscellaneous 

discharge measurements, regression analyses, averages from 

the streamflow loss studies of Bennett (1990), and later more 

complete discharge records. Gaging stations with useable 

record, their general location, and their corresponding map 

numbers (table A2; figs. B1, B2) are: (1) 4 mi southeast of 

Arco (501), (2) at the inlet to spreading area A (502), (3) at 

the outlet of spreading area A to spreading area B (503), (4) 

downstream of the diversion dam used to divert flow into 

spreading area A (504), (5) at the Lincoln Boulevard bridge 

near the RTC and INTEC (505), and (6) above the Big Lost 

River Sinks (506).

Streamflow infiltration from the Big Lost River in the 

simulated area, which includes sections of the river upstream 

of the Arco gaging station, was simulated as constant flow 

(125.3 ft3/s) for the steady-state model, based on annual mean 

discharge for a continuous period of record from 1966 to 1980 

and average infiltration rates in the Big Lost River channel. 

This infiltration varies spatially; for example, infiltration from 

the river channel was estimated to vary from 1 to 4 (ft3/s)/mi2

between Arco and the Big Lost River Sinks to as much as 

28 (ft3/s)/mi2 at the Big Lost River Sinks (Bennett, 1990, p. 24 

and 26). For the transient model, based on average measured 

discharge and estimated evaporation for 4-month intervals 

between 1981 and 1995 (table C1), Big Lost River streamflow 

infiltration ranged from 0 to 641 ft3/s. 

Evaporation losses were calculated and simulated for the 

Big Lost River Sinks, Playas, channels, and spreading areas. 

Evaporation rates were calculated using a modified form of 

equations used by the Idaho Department of Water Resources 

(Tony Olenichak, Water District #1, written commun., 2006) 

to estimate water loss from reservoirs and from data collected 

at the Aberdeen Experiment Station about 40 mi southsouthwest of the spreading areas (http://www.usbr.gov/pn/

agrimet/webarcread.html).
38 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

The modified equations are:

EV PE Sc, = × (1a)

or

EV ETr Cp Sc,

where

EV is daily evaporation rate (ft/d) from large water

bodies;

PE is 24-hour pan evaporation (ft/d);

Sc is standard coefficient, 0.7, for converting pan

evaporation to large surface area;

ETr i

= × ×

s reference evapotranspiration (ft/d) (1982

Kimberly-Penmen equation); and

Cp is correlation factor, 1.18 for converting ETr

to Pe.

(1b)

The average annual evaporation in the model area was 

calculated using the average evaporation rate for the stress 

period and the estimated areas for all stream reaches of the 

Big Lost River during the stress period. Equation 1a and PE 

from records at the Aberdeen Experiment Station were used 

to calculate EV for stress periods prior to about 1990, and for 

1990 through 1995 EV was calculated with equation 1b and 

ETr. The average ETr using May through August monthly 

data for the period 1991–2005 at the Aberdeen Experiment 

Station was 0.022 ft/d. The calculated value of EV for the 

same period was 0.018 ft/d. These are similar to a previous 

estimate of evaporation from the Big Lost River Playas of 

0.01–0.02 ft/d (Barraclough, Teasdale, and others, 1967, 

p. 24). The estimated evaporation ranged from 1 percent of 

average flow in river channels to more than 7 percent of flow 

in the spreading areas.

The Little Lost River and Birch Creek have short river 

reaches on the ESRP (fig. 14) that were estimated to contribute 

small amounts of infiltration to the ESRP aquifer. Infiltration 

from the Little Lost River and Birch Creek was simulated as 

constant flow (3 and 20 ft3/s, respectively) for the steady-state 

and transient models (table 4). These infiltration estimates 

were based on uncertain estimates of streamflow onto the 

ESRP due to discontinuous discharge records at gaging 

stations upgradient of the ESRP and infrequent observations of 

flow onto the ESRP. Infiltration to the aquifer from the Little 

Lost River was simulated along a 0.7 mi reach of river channel 

near Howe (Map No. 611, fig. 14; fig. B2). The infiltration rate 

was assumed to be greater than average channel infiltration 

rates for the Big Lost River because the sediments at the 

mouth of the Little Lost River are closer to the source area. 

Infiltration of flow diverted from Birch Creek onto the ESRP 

was simulated along a 12 mi length of trench and section of 

an old channel north of TAN (Map No. 612, fig. 14; fig. B2). 

Streamflow in this reach of the river represents return flows 

from upstream Birch Creek diversions that are used to operate 

a hydroelectric power generation facility several miles east of 

Birch Creek (Ackerman and others, 2006, p. 33). Birch Creek 

diversions were estimated to be 40 ft3/s using powerplant 

records from 1988 to 1995 (Ted S. Sorenson, Sorenson 

Engineering, written commun., March 2001). For 6 months of 

the year, return flows are diverted to the northeast and are used 

for irrigation. During the nonirrigation season, return flows 

are routed to the area north of TAN. Infiltration from the Birch 

Creek diversion returns was estimated to occur for one-half 

of the year and was simulated as constant at 20 ft3/s (table 4). 

Infiltration from the Little Lost River and Birch Creek were 

simulated as constant flow for the steady-state and transient 

models. No evaporation losses were estimated or simulated 

for the Little Lost River or Birch Creek due to the relatively 

poor estimates of infiltration and short river reaches of these 

streams in the model area.

Irrigation and Industrial Return Flows

Infiltration of excess applied agricultural irrigation 

water in the northern part of the study area was simulated 

at a constant annual rate and applied seasonally in transient 

stress periods representing the period May through August. 

Annual infiltration rates of 2.55 × 10-8 and 4.66 × 10-9 ft/s for 

surface-water and groundwater irrigation areas, respectively, 

were used and are equivalent to those of Spinazola (1994, 

p. 32-33, fig. 38) (table 5). Irrigation infiltration rates were 

applied uniformly to layer 1 cells within individual irrigation 

areas (fig. 18). Refined estimates of the boundaries and types 

of infiltration areas used for model simulations resulted in 

slightly different rates of irrigation infiltration than that given 

in the conceptual model (tables 4 and 5).

Industrial return flows consisting of infiltration of 

landscape irrigation at INL facilities, and disposal of industrial 

waste to ponds and ditches at these facilities were simulated as 

temporally variable using the Well Package (fig. 18; table D1). 

The steady-state total industrial return flow was 2.6 ft3/s and 

transient totals ranged from 1.8 to 6.9 ft3/s per stress period. 
Numerical Model 39

Table 5. Steady-state and transient simulated water budgets, Idaho National Laboratory and vicinity, Idaho.

[Steady-state and Initial condition: Stress period 1, steady state, 1980. Maximum inflow: Stress period 9, May-August 1983. Minimum inflow: Stress period 

44, January-April 1995. Flow in cubic feet per second, rounded to nearest tenth. Abbreviations: –, not simulated; NA, not applicable]

Budget component

Model implementation

Boundary 

condition

Input files Volumetric budget

Steady-state Transient

Initial 

condition

Maximum 

inflow 

Minimum 

inflow 

Inflow

Recharge from precipitation Specified flow 70.0 70.0 70.0 70.0 70.0

Streamflow infiltration Big Lost River 1 Specified flow 125.3

Little Lost River 3.0

Birch Creek 20.0

Streamflow infiltration subtotal 148.3 148.3 143.4 692.1 23.0

Irrigation infiltration Specified flow 21.6

Industrial water use returns 5.9

Irrigation and industrial subtotal 27.5 27.5 27.5 71.1 4.3

Northwest mountain-front boundary underflow

Big Lost River Specified flow 361.0

Little Lost River 223.0

Birch Creek 62.0

Northeast regional-underflow boundary 1,225.0

Southeast-flowline boundary No flow – – – – –

Underflow subtotal 1,871.0 1,871.0 1,871.0 1,871.0 1,871.0

Flow across the base of aquifer No flow – – – – –

Decrease in storage – – – 17.2 95.6

Total inflow 2,116.7 2,116.7 2,111.9 2,721.4 2,064.9

Outflow

Southwest regional-underflow boundary Head dependent 

flow

NA 2,072.0 2,067.2 2,068.6 2,056.0

Irrigation well discharge Specified flow 37.2 2,056.7

Industrial well discharge 7.6

Irrigation and industrial subtotal 44.8 44.8 44.8 121.2 5.4

Increase in storage – – – 531.4 2.9

Total outflow NA 2,116.8 2,112.0 2,721.2 2,065.0

Budget residual -0.1 -0.2 0.0 0.1

Volumetric budget difference, percent .003 .008 .006 .003

1

 Mean annual discharge from 1966 to 1980 for steady-state, and total discharge minus evaporation for all stress periods in transient models. 
40 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Figure 18. Distribution of areas where returned water from irrigation and industrial use infiltrates as used in the 

calibration of groundwater flow models, Idaho National Laboratory and vicinity, Idaho.

ID19-0164_GWflow_fig. 18

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Big Lost River

Birch

Creek

Mud Lake

Camas Creek

Big Lost River

Sinks and 

Playas

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.

Howe

Mud

Lake Terreton

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

MFC

INTEC

NRF

RTC

CFA

RWMC

TAN

113°00' 112°45' 112°30' 112°15'

43°

30'

43°

45'

44°

00'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

EXPLANATION

Model area boundary

Surface-water irrigation infiltration

Groundwater irrigation infiltration

Idaho National Laboratory boundary

Industrial infiltration—circle ( ) indicates location of 

units too small to be viewable at this scale.

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Material and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Site facilities

0 10 MILES

0 10 KILOMETERS

Atomic

City

East

Butte

Middle

Butte

Big Southern

Butte
Numerical Model 41

Northwest Mountain-Front Boundary

Inflow to the study area across the northwest 

mountain‐front boundary represents underflow from the

alluvial-fill aquifers of the mountain valleys of Birch Creek, 

Little Lost River, and Big Lost River and underflow from the 

carbonate and volcanic rocks forming the mountain fronts of 

the Bitterroot Range, Lemhi Range, Lost River Range, and 

Pioneer Mountains (fig. 9). Inflow from the mountain fronts 

was specified as zero. Inflows from the stream valleys were 

simulated as specified flow at boundary cells corresponding 

to the locations of the Birch Creek, Little Lost River, and Big 

Lost River valleys at the model boundary using the Flow and 

Head Boundary (FHB) Package of MODFLOW-2000 (Leake 

and Lilly, 1997) (fig. 14). In the transient model, these flows 

were simulated as constant with time. Underflow from the 

tributary valleys (table 5) was calculated as basin yield minus 

simulated streamflow infiltration and distributed across the 

model boundary surface based on estimates of the widths 

of the tributary valley aquifers, the thickness and hydraulic 

conductivity of the ESRP aquifer locally, and knowledge of 

local conditions. Due to the uncertainty of the vertical location 

of underflow from the Birch Creek valley, flow entering the 

model from this valley was distributed uniformly across 

boundary cells for the entire thickness of the ESRP aquifer, 

which, at this model boundary, consists of the top four model 

layers. Inflow entering the model area from the Little Lost 

River valley was distributed uniformly across boundary cells 

in the top three model layers. Inflow into the model area 

was restricted to the top three model layers because these 

layers constitute the highly conductive hydrogeologic unit 1. 

Hydrogeologic unit 2, a lower conductivity unit, is in model 

layer 4 at this location, whereas layers 5 and 6 are not present. 

Inflow from the Big Lost River valley was distributed only to 

model layer 1, a simplified representation of the movement of 

underflow downward in a complex layering of water bearing 

zones at the mouth of the valley. 

Northeast Boundary

Inflow to the model across the northeast boundary 

represents underflow from the ESRP aquifer upgradient of 

the boundary (fig. 14) and was simulated as specified flow 

using the FHB Package. Flow across the boundary was 

distributed to model layers 1 through 5 (layer 6 is absent 

along this boundary) in proportion to hydraulic conductivity 

distribution estimates across the boundary. The presence of 

highly transmissive hydrogeologic unit 1 along a 20 mi stretch 

of the southeastern part of the boundary (fig. 13), for example, 

resulted in the allocation of a large proportion (64 percent) of 

the flux to this area.

Well Injection and Withdrawal

Industrial water injection through disposal wells and 

withdrawals from production wells at INL facilities, and 

withdrawals from irrigation wells were simulated using the 

Well Package in model layers 1 through 5 at model cells 

corresponding to well locations and times (tables E1 and F1). 

Withdrawal and injection rates for industrial wells varied 

seasonally and were based on the well construction, hydraulic 

conductivity, and the history of the well. Irrigation water 

withdrawals in the northern and eastern parts of the model 

area (fig. 18) were simulated as constant from year to year and 

were applied during the irrigation season, May to August of 

each year. Withdrawal rates for irrigation wells were uniform 

and applied at locations and depths equivalent to those in 

Spinazola (1994, fig. 29).

Southwest Boundary

Outflow across the southwest boundary was not specified, 

but was simulated as head-dependent flow (fig. 14) using the 

Drain Package. This configuration was used in part for reasons 

of parsimony—to avoid over specifying boundary conditions, 

and in part because this configuration provides head values at 

one model boundary, which allows a unique solution for head 

to be calculated. Outflow occurs across this boundary in all 

six model layers and is a function of the conductance along, 

and the head difference across, the boundary. The boundary 

condition used for the southwest boundary was conceptualized 

as a downgradient part of the aquifer with identical dimensions 

as the cells immediately upgradient of this boundary. The 

conductance for the boundary cells was calculated using the 

estimated value of hydraulic conductivity for hydrogeologic 

unit 3, the layer thickness, and cell boundary length. The 

estimated value for hydraulic conductivity was determined 

through sensitivity testing of the estimated range of hydraulic 

conductivity values (850–1,150 ft/d) in this part of the 

aquifer (Ackerman and others, 2006, p. 35). Results indicate 

that model budget (mass balance) errors were smallest (less 

than 0.01) and parameter estimates more stable and efficient 

(closure with parameter-estimation closure criteria less than 

0.015) for a hydraulic conductivity estimate corresponding to 

the largest (1,150 ft/d) estimated value. The head difference 

was the calculated decrease in head between individual 

boundary cells and an assumed head distribution just 

downgradient of the boundary. The assumed head values were 

constant, uniform with depth, and equal to the interpolated 

1980 altitude of the water table (Lindholm and others, 1988). 

No flow was simulated across the northwestern most 3.75 mi 

in layers 1–4 (fig. 14) and 6.25 mi in layers 5 and 6 because 

the estimated flow direction in this area was approximately 

parallel to the model boundary (Lindholm and others, 1988).
42 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Model Calibration

Model calibration is an iterative process of adjusting 

the 3-D distribution or structure of aquifer properties, 

aquifer property values, or properties of boundary conditions 

to improve the match between simulation results and 

observations. The calibration of the numerical models in this 

study involved (1) selecting and evaluating observed waterlevels in wells (hydraulic heads) to be used as observations

for calibrating the models; (2) defining discrete areas of the 

model grid, referred to as zones, where aquifer properties 

were assumed to be uniform (a form of parameterization); 

and (3) adjusting the distributions of zones and the values 

of aquifer properties in zones, referred to as parameters, 

to provide the best match between observed and simulated 

hydraulic head.

Model parameters include aquifer properties such as 

horizontal and vertical hydraulic conductivities, specific 

yields, and specific storage and may include boundary 

condition properties such as recharge, conductance, and heads. 

Observations applicable for calibrating this model include 

field-measured values of hydraulic heads distributed over 

space and time. 

The models in this study were calibrated by adjusting 

aquifer properties, either manually by “trial-and-error” or by 

using an inverse method (parameter estimation) to match 

observed heads or head differences. The trial-and-error 

method was used initially to calibrate the simplest versions of 

a steady-state model, primarily to test the overall reliability of 

the conceptual model and to select important design elements 

to include in subsequent models. 

The Observation, Sensitivity, and Parameter-Estimation 

(OSP) Processes in MODFLOW-2000 were used to calibrate 

the more complex versions of the steady-state and transient 

models (Hill and others, 2000). The OSP Processes use a 

modified Gauss-Newton nonlinear regression method to 

adjust values of selected input parameters in an iterative 

procedure to minimize the value of the weighted least-squares 

objective function. The objective function used is the sum 

of squared weighted residuals as described in the section 

Statistical Methods Used for Model Evaluation. The parameter 

estimation process used for this report produces statistics 

that were used to evaluate estimated parameter values and 

model‐calculated values of head or head differences.

Calibration Observations

Steady-state calibration observations were hydraulic 

heads (water levels) in wells, and transient calibration 

observations were heads and head differences (hereafter 

referred to as head observations, head-difference observations, 

or collectively as observations). Nearly all wells in the model 

area (207 well completion depths at 201 well locations) with 

available water-level data were used in model calibration. 

Some locations were represented by multiple observations 

that were attributed to a multi-depth piezometer nest or to 

modification of open intervals due to collapse, reconstruction, 

or deepening. Wells that were not used in model calibration 

(1) were completed below the aquifer, (2) were in close 

proximity to other wells with more complete records, or (3) 

had completion or record problems.

Observations for Steady-State Model Calibration

The steady-state model was calibrated using 201 head 

observations (table G1) from 201 well completion depths 

at 199 well locations (table A1; appendix B). The last 

measurement in 1980 was used for hydraulic heads at 108 well 

locations (110 well completion depths). For 91 other wells, 

most of which were completed after 1980, head measurements 

closest to 1980 levels or from 1992 to 1993, a period when 

water levels were close to levels in 1980, were used as the 

steady-state observations, and were considered reasonably 

representative of conditions in 1980. 

Observations for Transient Model Calibration

The transient model was calibrated using 328 head 

observations and 8,171 head-difference observations 

(table H1) from 206 well completion depths at 200 well 

locations (table A1; appendix B). All available water-level data 

were used in the transient calibration except for continuous 

water-level measurement records. Continuous records were 

resampled at one observation per month by selecting the 

measurement closest to the middle of the month. Transient 

calibration data included (1) 206 initial head observations (110 

from 1980, 3 prior to 1980, and 93 after 1980), (2) 8,171 headdifference observations for 151 well completion depths at 

146 well locations, and (3) 122 head observations from 6 well 

locations with few observations or near pumping wells for the 

period 1980–95. Head-difference observations were calculated 

internally in the model (Hill and others, 2000, p. 33) as the 

initial head observation minus the later head observation.

Observation Weights

Not all water-level data were equally suitable for model 

calibration because some wells (1) were open to multiple 

layers and hydrogeologic units (table 6), (2) had multiple 

open intervals, (3) were close to seasonal sources of inflow 

or pumpage, (4) were in areas of steep local hydraulic 

gradients, and (5) had different well-datum accuracies. 

Datum inaccuracies of as much as ±10 ft, caused by using 

topographic maps with a contour interval of 20 ft, contributed 
Model Calibration 43

Table 6. Summary of open intervals for well completions by hydrogeologic unit and model layer for observation wells used in model 

calibration, Idaho National Laboratory and vicinity, Idaho.

[Zones correspond to the parameter structure for the Big Lost Trough models of steady-state and transient groundwater flow; 207 well completions at 201 well 

locations]

Hydrogeologic 

zones

Model 

layers

Open to one model layer Open to two model layers Open to three or more model layers

Subtotal

1 2 3 4 6 1, 2 1, 5 1, 6 2, 3 3,4 1, 2, 3 1, 2, 4 2, 3, 4 3, 4, 5 1, 2, 

3, 4

1, 2, 3, 

4, 5, 6

Wells open to one hydrogeologic unit

1 ........... 27 --- --- --- --- 8 --- --- --- --- 2 --- --- --- --- --- 37

11 ........... 36 3 2 --- --- 7 --- --- --- --- --- --- --- --- --- --- 48

2 ........... 2 --- 2 --- --- --- --- --- --- --- 1 1 --- --- --- --- 6

22 ........... 5 --- 2 1 --- 1 --- --- --- --- 7 1 --- --- --- --- 17

3 ........... 7 --- --- --- --- --- --- --- 1 --- --- --- --- --- --- --- 8

33 ........... --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- 0

4 ........... 6 --- 1 --- --- 2 --- --- --- 1 5 --- --- --- --- --- 15

44 ........... 22 6 1 1 1 6 1 --- --- --- --- --- 1 --- 1 --- 40

6 ........... --- --- --- --- --- --- --- 1 --- --- --- --- --- --- --- --- 1

Subtotal 105 9 8 2 1 24 1 1 1 1 15 2 1 0 1 0

Wells open to multiple hydrogeologic units

1, 2 ........... --- --- --- --- --- 5 --- --- --- --- 2 --- --- --- --- --- 7

11, 22 ........... --- --- --- --- --- 15 --- --- --- 4 5 --- 1 --- 1 --- 26

1, 2, 3 ........... --- --- --- --- --- --- --- --- --- --- --- --- --- 1 --- 1 2

Subtotal 0 24 11

Total 125 52 30

the largest source of error for head observations in the steadystate model. To account for these errors and other conditions, 

all observation data were weighted in proportion to the 

reciprocal of the variance of their estimated measurement 

error. Higher‐weighted observations have greater influence in

the nonlinear regression procedure used to calibrate the model 

(Hill, 1998, p. 4, 13-14, 45).

For example, using the method given by Hill (1998, p. 

46-47), and the assumption that the 90-percent confidence 

interval for the datum (altitudes determined from topographic 

maps or surveys) is one-half the contour interval. The variance 

of the measurement error due to uncertainty in the datum 

derived from topographic maps with a 20 ft contour interval 

is 37 ft2. The variance due to datum errors is added to the 

variances for other components of measurement error, and 

the resultant weight is the inverse of the total variance. In this 

study, application of Hill’s method produced a weight of 0.027 

ft-2 for head observations in the steady-state model at wells 

with altitudes determined from topographic maps with a 20 ft 

contour interval, the smallest scaled weight for observations 

in this model (table 7). For the steady-state model, one of 

five observation weights between 0.027 and 2.70 ft-2 was 

applied to each head observation (table 7; table G1). Head 

observations for years other than 1980 were assigned lower 

weights. 

For the transient model, using head differences as 

observation data eliminated most of the datum errors 

from these observations. Other error components, such as 

equipment accuracy, barometric corrections, and measurement 

reproducibility dominated the variances for the two 

measurements used for a head difference. The total variance 

for the head-difference measurement is the sum of the variance 

of the two measurements. The observation weights used in the 

steady-state models were applied to head observations and one 

weight (60.6 ft-2) was applied to head-difference observations 

in the transient model (table 7). 

Because all head and head-difference observations used 

in calibrating the models were weighted, all weighted values 

such as observed heads, simulated heads, and differences 

between observed and simulated values are dimensionless.
44 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Statistical Methods Used for Model Evaluation

Several statistical measures and related graphs (Hill, 

1994; Hill, 1998; Hill and others, 2000; Hill and Tiedeman, 

2007) were used to evaluate the calibrated models and 

the estimated parameter values. Better models have three 

attributes: (1) estimated parameter values that are more 

realistic, (2) better fit of simulated values to observations, 

and (3) more randomly distributed weighted residuals. 

Descriptions of the statistical measures and graphical methods 

are organized in two general groups: (1) diagnostic statistics 

that quantify the quality of a calibrated model or are useful 

for selecting between alternative models and (2) inferential 

statistics that quantify the reliability of parameter estimates. 

A detailed discussion of these statistical measures and related 

graphs is available in Hill and Tiedeman (2007).

Evaluation of Model Fit

Evaluation of the model fit, which refers to how well 

observed and simulated values are matched by nonlinear 

regression, is one measure of model performance. Model 

fit was evaluated in the steady-state and transient models 

by considering the magnitude and distribution (statistically, 

spatially, and temporally) of the weighted residuals; weighted 

residuals are the weighted difference between observed 

and simulated values and represent the fit of the model in 

the context of the expected accuracy of the observations. 

Residuals for observations expected to be less accurate are 

de-emphasized relative to those that are more accurate when 

Table 7. Weights for steady-state and transient model observations, Idaho National Laboratory and vicinity, Idaho.

[Weighting statistic: Variance of the measurement error. Abbreviations: ft, foot; ft2, square foot; <, less than; >, greater than]

Weighting 

level

Features commonly affecting measurement 

error for hydraulic head

Hydraulic head Head difference

Weighting 

statistic 

(ft2

)

Weight 

(1/ft2

) Weighting 

statistic 

(ft2

)

Weight 

(1/ft2

)

Steadystate and 

transient

Transient

1 High-quality datum survey, well completed in one layer; annual water-level 

fluctuation < 1.5 ft.

0.370 2.70 0.0165 60.6

2 Well completed in two layers; annual water-level fluctuation 1.5–2.5 ft. 1.500 .667

3 Well completed in three layers; annual water-level fluctuation > 2.5 ft. 3.300 .303

4 Well completed in four or more layers, well deviation, estimated 

steady-state water-level for year other than 1980.

9.200 .109

5 Well datum from topographic map, steep local hydraulic gradient on 

water-table map.

37.000 .0270

weights are considered. (Hill and Tiedeman, 2007, p. 35). 

Statistical measures and graphs used to evaluate model fit 

were the (1) sum of squared weighted residuals, (2) average 

weighted residual, (3) standard error of the regression, 

(4) distributions of weighted residuals, and (5) normal 

probability graph and the related correlation coefficient R2

N .

Sum of Squared Weighted Residuals

The sum of squared weighted residuals is the sum of 

every squared weighted residual. The relative magnitude 

of the sum of squared weighted residuals among different 

models or different calibrations indicates whether a particular 

set of parameters provides a more or less precise model fit to 

all the observations. Smaller values indicate a more precise 

fit, but smaller values also can result when a larger set of 

parameters is used in the evaluation (Hill, and Tiedeman, 

2007, p. 95). The sum of squared weighted residuals was the 

weighted least-squares objective function that was minimized 

by the nonlinear regression method used to estimate model 

parameters. 

Average Weighted Residual

The average weighted residual is the simple arithmetic 

average of the weighted residuals (Hill, 1998, p. 21). An 

average weighted residual near zero may indicate that the 

associated set of parameters provides a precise model fit; an 

average weighted residual that is farther from zero indicates 

that the associated set of parameters provides a less precise 

model fit.
Model Calibration 45

Standard Error of the Regression

The standard error of the regression is the square root 

of the error variance, where the error variance is the sum 

of squared weighted residuals divided by the number of 

observations minus the number of estimated parameters. 

When weights are defined as the inverse of the variance of 

measurement error, the expected value of the standard error 

of the regression is 1.0. Successively higher values indicate 

diminished model fit. Due to model error and unaccounted 

errors in observations, values typically are greater than 1.0 

(Hill, 1998, p. 18-19). The standard error of the regression is 

not a very intuitive quantification of model fit because it is 

dimensionless. A more intuitive measure is the fitted standard 

deviation, defined as the product of the standard error of 

regression and the standard deviation of measurement error 

(square root of the variance of measurement error used to 

define the weights). The fitted standard deviation expresses the 

average fit of one group of observations in the corresponding 

units of measurement. This approach (Hill and Tiedeman, 

2007, p. 95-96) generally applies only if the fitted standard 

deviation summarizes the fit to a fairly large number of 

observations, as is the case for the transient model. 

Distribution of Weighted Residuals

Model fit also was evaluated using graphs of the 

weighted residuals with respect to weighted simulated values 

and independent variables such as space and time. A valid 

regression requires that the observation errors be random, have 

a mean of zero, and that the weighted errors be uncorrelated. 

Although the actual observation errors are unknown, these 

error requirements are inferred to be met if the weighted 

residuals are random, independent, and either are normally 

distributed or have predictable correlations (Hill, 1998, p. 23). 

Graphs of the weighted residuals plotted against weighted 

simulated values are used to evaluate whether the weighted 

residuals are independent and normally distributed (Hill, 1994, 

p. 3-4; Hill, 1998, p.20; Hill and Tiedeman, 2007, p.100-103). 

Weighted residuals are independent when small and large 

weighted residuals are not preferentially associated with, 

respectively, small and large weighted simulated values and 

when the range of weighted residual values does not increase 

or decrease with increasing weighted simulated values. 

Weighted residuals are normally distributed when the uniform 

distribution of residuals is about zero throughout the entire 

range of weighted simulated values. 

Model fit was evaluated spatially by mapping weighted 

residuals and inspecting the randomness of the values. For 

transient models, weighted residuals also are plotted on 

time-series graphs and maps to evaluate temporal distribution 

variability. Random distribution of weighted residuals is 

indicated when the signs and magnitudes of the weighted 

residuals show no discernable patterns (no clusters of positive 

or negative residuals or of large absolute values) and seem 

random.

Normal Probability Graphs and Related Correlation Coefficient

Normal probability graphs and the related correlation 

coefficient, R2

N, are used to further evaluate if weighted 

residuals are independent and normally distributed (Hill, 

1998, p. 23). Normal probability graphs are ordered weighted 

residuals, from smallest to largest, plotted against the 

standard normal statistic, which is the cumulative probability 

expected for each value assuming the values are independent 

and normally distributed. This plot should approximate a 

straight line—the correlation coefficient, R2

N, should be 

close to 1.0—when the weighted residuals are independent 

and normally distributed (Hill, 1994, p. 5, 19). When R2

N is 

significantly less than 1.0, the weighted residuals likely are not 

independent and not normally distributed (Hill, 1998, p. 23-24, 

appendix D).

Evaluation of Parameter Estimates

Parameter sensitivity, uniqueness, and uncertainty were 

measured with composite scaled sensitivities, parameter 

correlation coefficients, and linear confidence intervals, 

respectively. To evaluate the validity of linear confidence 

intervals, the modified Beale’s measure was used to test 

the linearity of the steady-state and transient models. The 

effect of individual observations on parameter estimates was 

evaluated with Cook’s D and DFBETAS statistics. In addition 

to the use of statistical measures, parameter values and their 

confidence intervals were compared to acceptable or expected 

values gleaned from field and laboratory measurements and 

estimates, and from published values for similar aquifer 

materials.

Composite Scaled Sensitivities

Composite scaled sensitivities (CSS) indicate the total 

amount of information for defining parameters and estimating 

parameter values provided by all the observations. The CSS 

are calculated using sensitivities of the simulated equivalent 

of each observation with respect to one parameter value 

(Hill, 1998, p. 14). A single sensitivity value indicates the 

amount that the simulated equivalent would change when the 

parameter value is changed. The CSS for a parameter that is 

more than 2 orders of magnitude smaller than the largest CSS, 

or that is less than a suggested critical value of 1.0, indicates 

that the parameter is likely to be poorly estimated and will 

have large confidence intervals (Hill and Tiedeman, 2007, 

p. 50-51). Larger values of CSS indicate that a parameter 

likely can be estimated because the information provided 

by observations dominates the effects of observation error. 

Illustrations in this report show the normalized CSS, which is 

the value divided by the maximum CSS for the model.
46 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Parameter Correlation Coefficients

Parameter correlation coefficients indicate whether 

parameter values can be uniquely estimated by regression. 

Parameter correlation coefficients are calculated for a pair of 

parameters as the covariance between the parameters divided 

by the product of the variance of each parameter. Parameter 

correlation coefficients range from -1.00 to 1.00, and absolute 

values less than 0.95 indicate that the parameter pair probably 

can be estimated uniquely (Hill and Tiedeman, 2007, 

p. 51-54).

Linear Confidence Intervals

Linear confidence intervals are used to quantify 

parameter uncertainty. Linear confidence intervals require 

that the observation errors be independent and normally 

distributed, which is evaluated by analyzing the distribution 

of weighted residuals. The width of a confidence interval 

is a measure of the likely precision of the estimate for a 

parameter. Greater precision produces narrower confidence 

intervals (Hill and Tiedeman, 2007, p. 138). The accuracy 

of linear confidence intervals is compromised if the model 

is significantly nonlinear, thus a measure of the linearity of 

the model is necessary to assess the validity of the linear 

confidence intervals.

Modified Beale’s Measure

The modified Beale’s measure (Nb) is used to assess 

model nonlinearity. Calculation of Nb requires generating 

sets of parameter values near the limits of their confidence 

regions and using the values to generate simulated equivalents 

of the calibration observations and linearized estimates of 

the simulated equivalents. Nb is a measure of the difference 

between the simulated equivalents of the calibration 

observations and the linearized estimates of the simulated 

equivalents. The degree of model linearity is assessed by 

comparing the calculated Nb with two critical values that are 

a function of a value from the F probability distribution (F). 

The model is effectively linear if Nb is less than 0.09/F and 

nonlinear if Nb is greater than 1.0/F. Values for Nb between 

these two critical values indicate that the model is moderately 

nonlinear (Hill and Tiedeman, 2007, p. 142-145).

Cook’s D and DFBETAS

Cook’s D is a measure of the influence of one observation 

on a set of parameter estimates (Hill and Tiedeman, 2007, 

p. 134-136). Weighted residuals and a leverage statistic 

are used to calculate Cook’s D. Cook’s D values that are 

larger than a critical value of 4 divided by the number of 

observations indicate that the observation has a large influence 

on the estimation of the set of parameters, relative to other 

observations with Cook’s D values less than the critical 

value. The likelihood of any observation being influential to a 

parameter generally decreases as the number of observations 

increases. The DFBETAS statistic measures the influence of 

one observation on one parameter. DFBETAS values larger 

than a critical value of 2 divided by the square root of the 

number of observations indicate that an observation may 

be influential in estimating the parameter. The likelihood of 

any observation being influential to a parameter generally 

decreases as the number of observations increases (Hill and 

Tiedeman, 2007, p. 136).

Steady-State Calibration

Steady-state calibration involved (1) selecting a zonation 

scheme for the model to accommodate the spatial distribution 

of hydrogeologic units and variations of sediment content 

within hydrogeologic units; (2) parameterization of hydraulic 

properties for three different distributions of sediment 

content within hydrogeologic units; (3) applying parameter 

estimation techniques to the models representing the three 

conceptualizations of sediment content (parameter structures); 

and (4) using statistical measures to select a parameterization 

with the best model fit and to evaluate model sensitivity 

to changes in system geometry, boundary conditions, and 

parameters.

The aquifer in the model consists of hydrogeologic 

units 1, 2, and 3, which represent groupings of fractured 

basalts and interbedded sediment, and rhyolite domes that 

constitute a small remainder of the aquifer volume. Each of 

the hydrogeologic units are represented as homogeneous, 

anisotropic porous media. In this representation of the aquifer, 

the small-scale heterogeneities and anisotropies are not 

preserved; the hydraulic conductivity of each hydrogeologic 

unit reflects the aggregate lithology, thickness, and number of 

basalt flows and sedimentary interbeds in each hydrogeologic 

unit. Three representations of the hydrogeologic units 

(parameter structures) within the Big Lost Trough were 

evaluated. These representations are referred to as the 

(1) no-sediment model, in which no additional characteristics 

of the hydrogeologic units are considered other than location 

in space; (2) Whitehead sediment model (Ackerman and 

others, 2006, fig. 12A), in which the hydraulic properties 

are estimated within hydrogeologic units according to the 

relative abundance of sediment as interpreted in the RASA 

study (Whitehead, 1992); and (3) Big Lost Trough model 

(Ackerman and others, 2006, fig. 12B), in which the hydraulic 

properties are estimated within hydrogeologic units according 

to the presence of abundant sediment.

Initial steady-state calibration used trial-and-error 

methods to determine if a numerical model could reasonably 

represent the conceptual model and be consistent with 
Model Calibration 47

estimates of flow across boundaries. Models with increasing 

complexity were tested starting from a two-dimensional 

confined model based on a simple distribution of horizontal 

hydraulic conductivity and progressed to a three-dimensional, 

three-layer confined model with different distributions of 

sediment content modifying the hydraulic properties within 

three hydrogeologic units, and with observations only in layer 

1. After examination of the trial-and-error modeling results, 

the following improvements to the model were determined: 

(1) represent the southwest boundary as head-dependent flow 

to improve mass balance; (2) model the influence of sediment 

content on hydraulic conductivity to improve model quality in 

the north-central part of the model area (fig. 7); (3) configure 

head observations to represent the layers represented by 

the well open intervals so multi-layer flow could be more 

realistically represented and observations could influence 

aquifer parameters in lower layers; and (4) subdivide the 

representation of hydrogeologic unit 3 into north and south 

zones to improve simulated heads and gradients in the north 

part of the study area. Trial-and-error experimentation with 

these simple steady-state models provided confidence that 

the numerical model reasonably represented the conceptual 

model.

The steady-state model configurations described in this 

report are three-dimensional, six-layer unconfined models 

representing 1980 conditions with average annual values 

specified for all inflow and all outflow except for flow out of 

the model area to the southwest. The three different parameter 

structures—no sediment, Whitehead, and Big Lost Trough—

corresponded to separately calibrated steady-state models with 

individual parameterizations based on hydrogeologic units 

subdivided into zones according to sediment content.

The implementation of the MODFLOW-2000 

groundwater flow model, as discussed throughout this report, 

used the Layer-Property Flow Package (Harbaugh and others, 

2000, p. 22). All calibrated models assumed unconfined 

conditions, that is, the thickness of the upper layer varied 

with the altitude of the water table, which ranged between 

about 4,100 and 4,600 ft. The units of length and time used 

for model input were feet and seconds. For consistency in 

presentation with the conceptual model report (Ackerman 

and others, 2006), the values of hydraulic conductivity are 

reported in units of feet per day in this report. Values of all 

parameters were log transformed in the regression procedure 

used for model calibration. For the final calibration, the 

criteria for maximum absolute change in head and residual 

in forward model runs (Hill 1990, p. 14) were set to 0.001 ft 

and 0.0001 ft3/s for the steady-state model calibration. These 

criteria were set to 0.001 ft and 0.001 ft3/s for the transient 

model calibration. The budget error in forward model runs 

was less than 0.001 percent. For evaluation of alternate 

parameterizations and for sensitivity analyses used to evaluate 

budget components and modifications to the geologic 

framework, the criteria for maximum absolute change in 

head and residual (Hill, 1990, p.14) were set to 0.01 ft and 

0.001 ft3/s, respectively, unless otherwise noted. In these 

simulations, the budget error was less than 0.01 percent. 

Hydrogeologic Zones

Hydrogeologic zones are groups of model cells with 

uniform hydraulic properties that compose part or all of 

a hydrogeologic unit or rhyolite domes (fig. 5). Initial 

trial‐and-error model runs, and examination of CSS for each

of the three steady-state parameter structures, indicated that 

observations of head are sufficient to separate hydrogeologic 

unit 3 into northern and southern sections. The northern 

section composes shallower areas of hydrogeologic unit 3 that 

constitute the entire saturated thickness of the aquifer, and 

the southern section composes deeper parts of hydrogeologic 

unit 3. In the northwest part of the model area, hydrogeologic 

unit 3 was designated unit 3N and in the rest of the model 

area, hydrogeologic unit 3 was designated as unit 3S. In each 

parameter structure hydrogeologic units 1, 2, 3S, 3N, and 

rhyolite domes were represented by zone numbers 1, 2, 3, 4, 

and 6 respectively. Zone numbers with multiple digits (for 

example, 11, 333) were used in the Whitehead and Big Lost 

Trough parameter structures to represent zones containing 

different amounts of sediments.

The no-sediment parameter structure was conceptualized 

as sediment having little influence on the hydraulic properties 

of the aquifer. Five hydrogeologic zones represented the 

hydrogeologic units and rhyolite domes (table 8). In the 

Whitehead and Big Lost Trough parameter structures sediment 

was conceptualized as influencing the hydraulic properties 

of the aquifer. This conceptualization was summarized by 

Ackerman and others (2006, p. 22) as:

...in areas where large amounts of sediment were 

deposited, such as in the Big Lost Trough, hydraulic 

conductivity of basalt interflow zones probably is 

greatly reduced because sediment fills cracks, joints, 

fissures, and fractures, reducing the original porosity 

of the basalt and impeding groundwater flow.

In both these parameter structures, hydrogeologic zones 

represented parts of hydrogeologic units and rhyolite domes 

based on the thickness of sediment in the stratigraphic section. 

In the Whitehead parameter structure, 12 zones represented 

areas with estimated sediment thicknesses of less than 100 ft 

(zones 1, 2, 3, and 6), 100 to 499 ft (zones 11, 22, 33, and 44), 

and more than 500 to 999 ft (zones 111, 222, 333, and 444) 

(table 8). In the Big Lost Trough parameter structure nine 

zones represented areas with sediment thicknesses of less (1, 

2, 3, 4, and 6) or more (11, 22, 33, and 44) than 11 percent of 

aquifer thickness (fig. 19; table 8).
48 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Hydraulic 

property 

parameter

Parameter structure

Steady-state models Transient 

model

No 

sediment

Whitehead 

sediment

Big Lost 

Trough 

sediment

Big Lost 

Trough 

sediment

Hydrogeologic zones where the presence of sediment 

does not affect hydraulic property estimates

HC1 1 1 1 1

HC2 2 2 2 1

HC3 3 3 3 1

HC4 4 – 4 1

HC6 6 6 6 1

SY1 – – – 1

SY2 – – – 2

SY3 – – – 3

SY4 – – – 4

SY6 – – – 6

Hydraulic 

property 

parameter

Parameter structure

Steady-state models Transient 

model

No 

sediment

Whitehead 

sediment

Big Lost 

Trough 

sediment

Big Lost 

Trough 

sediment

Hydrogeologic zones where the presence of sediment 

does affect hydraulic property estimates

HC11 – 11 11 1

HC111 – 111 – –

HC22 – 22 22 1

HC222 – 222 – –

HC33 – 33 33 1

HC333 – 333 – –

HC44 – 44 44 1

HC444 – 444 – –

SY11 – – – 11

SY22 – – – 22

SY44 – – – 44

Hydrogeologic properties constant throughout the model domain

SS – – – Fixed

VANI Estimated Fixed Estimated 1

1

 Value from Big Lost Trough steady-state model

Table 8. Hydraulic property parameters and corresponding zones used in parameter structures for steady-state and transient models, 

Idaho National Laboratory and vicinity, Idaho.

[Parameter values corresponding to zones in bold type were optimized, estimated value optimized during model calibration. Parameter values corresponding to 

zones in italic indicate parameter is during model calibration. Abbreviations: HC, hydraulic conductivity; SY, specific yield; SS, specific storage; VANI, ratio of 

horizontal to vertical hydraulic conductivity; –, not used in parameter structure]
Model Calibration 49

ID19-0164_GWflow_fig. 19A

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

0 10 20 MILES

0 10 20 KILOMETERS

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER

PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

 Hydrogeologic zones, model layer 1

1—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally less than 11 percent

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally less than 11 percent

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

4—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

11—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally more than 11 percent

22—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

44—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

6—Silicic rocks, including rhyolite domes and andesite

EXPLANATION

Model area boundary

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering 

Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Mud Lake

A.

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

Figure 19. Distribution of hydrogeologic zones for model (A) layer 1, (B) layer 2, (C) layer 3, (D) layer 4, (E) layer 5, and (F)

layer 6 for Big Lost Trough parameter structure used to simulate steady-state and transient groundwater flow at the Idaho 

National Laboratory and vicinity, Idaho.
50 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 19B

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

spreading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

0 10 20 MILES

0 10 20 KILOMETERS

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

 Hydrogeologic zones, model layer 2

1—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally less than 11 percent

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally less than 11 percent

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

4—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

11—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally more than 11 percent

22—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

44—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

6—Silicic rocks, including rhyolite domes and andesite

EXPLANATION

Model area boundary

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering 

Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Mud Lake

B.

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

Figure 19.—Continued.
Model Calibration 51

ID19-0164_GWflow_fig. 19C

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

Mud Lake

0 10 20 MILES

0 10 20 KILOMETERS

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

 Hydrogeologic zones, model layer 3

1—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally less than 11 percent

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally less than 11 percent

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

4—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

11—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally more than 11 percent

22—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

44—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

6—Silicic rocks, including rhyolite domes and andesite

Model area boundary

EXPLANATION

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering 

Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Model layer inactive

C.

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

Figure 19.—Continued.
52 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 19D

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

0 10 20 MILES

0 10 20 KILOMETERS

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Model area boundary

EXPLANATION

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering 

Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Model layer inactive

D.

 Hydrogeologic zones, model layer 4

1—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally less than 11 percent

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally less than 11 percent

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

4—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

11—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally more than 11 percent

22—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

33—Intermediate-age rocks consisting of slightly altered fractured basalt and

sediment, with a sediment thickness of generally more than 11 percent

44—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

6—Silicic rocks, including rhyolite domes and andesite

Mud Lake

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

Figure 19.—Continued.
Model Calibration 53

ID19-0164_GWflow_fig. 19E

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

0 10 20 MILES

0 10 20 KILOMETERS

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

E.

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

Model area boundary

EXPLANATION

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering 

Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Model layer inactive Hydrogeologic zones, model layer 5

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally less than 11 percent

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

4—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

22—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

33—Intermediate-age rocks consisting of slightly altered fractured basalt and

sediment, with a sediment thickness of generally more than 11 percent

44—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

6—Silicic rocks, including rhyolite domes and andesite

Mud Lake

Figure 19.—Continued.
54 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 19F

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

spreading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

East

Middle Butte

Butte

Big Southern

Butte

0 10 20 MILES

0 10 20 KILOMETERS

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Model area boundary

EXPLANATION

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering 

Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Model layer inactive Hydrogeologic zones, model layer 6

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

4—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

33—Intermediate-age rocks consisting of slightly altered fractured basalt and

sediment, with a sediment thickness of generally more than 11 percent

44—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

6—Silicic rocks, including rhyolite domes and andesite

Mud Lake

F.

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

Figure 19.—Continued.
Model Calibration 55

Model Parameters

In this report, a model parameter is defined as a value 

assigned for a specific hydraulic property for one or more 

model cells (zones). Model parameters in the steady-state 

models were horizontal hydraulic conductivity (HC) and 

vertical anisotropy (VANI), the ratio of horizontal to vertical 

hydraulic conductivity. When more parameters are defined 

than can be estimated in a model, some parameter values are 

not estimated and must be specified (fixed) during model 

calibration. One parameter value for VANI, applied uniformly 

throughout the model domain, and multiple parameter 

values for HC were used in each of the three steady-state 

models. Single HC parameter values were estimated or fixed 

for each hydrogeologic zone (table 8). The no-sediment, 

Whitehead, and Big Lost Trough models had five, eight, 

and eight estimated parameters and one, five, and two fixed 

parameters (table 8), respectively. The parameter values 

not estimated using parameter estimation were set to values 

within reasonable limits derived from field and laboratory 

measurements and estimates and published values for 

similar aquifer materials (table 3). The parameter values not 

estimated most often were those with lowest relative values 

of CSS (fig. 20) indicating that less information is provided 

by observations for defining those parameters and estimating 

parameter values. Parameters with lower CSS are likely to be 

poorly estimated and have large confidence intervals. For the 

Whitehead sediment model, many parameters could not be 

estimated.

The fixed HC and VANI parameter values (table 8) were 

determined from initial trial-and-error modeling. Hydraulic 

conductivity was specified to be 86 ft/d for parameters HC6, 

HC33, HC333, and HC44 and corresponds to a hydraulic 

conductivity value near the maximum for basalts that are 

thicker or cut by dikes (categories 2 and 3 of Anderson 

and others, 1999, p. 27, figs. 8 and 9). The specified value 

represents hydrogeologic units composed of slightly altered 

and thicker basalt flows (HC33, HC333, and HC44), or 

thicker, less vesicular intermediate composition rocks that 

have fewer flow contacts (HC6). The value also is equivalent 

to the geometric midpoint of hydraulic conductivity, 88 ft/d, 

of the range of values for hydrogeologic unit 3 (table 3). VANI 

was specified to be 5,600 in the Whitehead model (table 8).

Model Results and Evaluation

The estimated values of horizontal hydraulic conductivity 

for each hydrogeologic zone, vertical anisotropy of the 

model area, and simulated hydraulic head and flux for each 

active cell in the model area constituted the steady‐state

model results. Each of the three models (no-sediment, 

Whitehead, and Big Lost Trough) was calibrated with the 

same boundary conditions and observations. Results of the 

estimated parameter values for each of the model calibrations 

are summarized in table 9. The Big Lost Trough model was 

determined to be the best of the three models by comparing 

model fit, parameter correlation coefficients (table 10), CSS 

(fig. 20), and the visual comparison of simulated heads to 

observed heads. The results for the Big Lost Trough model 

were further examined by comparing parameter values to 

ranges of expected values and by evaluating the sensitivity 

of the model to changes in system geometry or boundary 

conditions.

The highest values of the sum of squared weighted 

residuals and standard error of regression were in the 

no-sediment model, and the lowest values were in the Big Lost 

Trough model (table 10). The maximum parameter correlation 

coefficient for the models was 1.00 (between HC3 and VANI) 

for the no-sediment model, 0.94 (absolute value, between HC1 

and HC2) for the Whitehead model, and 0.92 (between HC3 

and VANI) for the Big Lost Trough model. The maximum 

correlation coefficient of 1.00 between HC3 and VANI in 

the no-sediment model indicates that these parameters could 

not be uniquely estimated in this model, whereas the smaller 

maximum parameter correlation coefficients in the Whitehead 

and Big Lost Trough models (less than 0.95) indicate that 

all their parameters could be uniquely estimated (table 10). 

Examination of water-table (layer 1) contours of simulated 

head showed that differences in gradient features presumed 

to relate to the abundance of sediment in the aquifer were 

reproduced better with the Whitehead and Big Lost Trough 

models than with the no-sediment model.

Five of six parameters were estimated in the no-sediment 

model. Eight of 13 and 8 of 10 parameters were estimated in 

the Whitehead and Big Lost Trough models, respectively, and 

CSS for all estimated parameters in the Whitehead model and 

all but HC4 in the Big Lost Trough model were large enough 

to indicate that these parameters were well estimated (fig. 20). 

The Big Lost Trough model was determined to best 

represent the hydrogeologic zones and model parameters for 

the steady-state model. The Big Lost Trough model had (1) the 

smallest sum of residuals, (2) the lowest maximum parameter 

correlation, (3) large CSS, (4) simulated heads that compared 

to observed heads as well or better than the other models, and 

(5) the definitive (interpretations were based on more complete 

geologic and geophysical logs) and numerous data used to 

create the distribution of sediment for the parameterization 

(Ackerman and others, 2006, p. 22). The no-sediment and 

Whitehead models, therefore, will not be discussed further in 

this report. 
56 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 20

0.001

0.010

0.100

1.000

HC1 HC2 HC3 HC4 HC6* VANI

Normalized composite scaled sensitivity

B. Whitehead model

0.001

0.010

0.100

1.000

HC1 HC2 HC3 HC6* HC11 HC22 HC33* HC44* HC111 HC222 HC333* HC444 VANI*

Normalized composite scaled sensitivity

C. Big Lost Trough model

0.001

0.010

0.100

1.000

HC1 HC2 HC3 HC4 HC6* HC11 HC22 HC33* HC44 VANI

Normalized composite scaled sensitivity

A. No-sediment model

Parameter name

Figure 20. Normalized composite scaled sensitivities for models of steady-state groundwater flow, Idaho National 

Laboratory and vicinity, Idaho. Asterisks indicate that the parameter value was fixed, rather than estimated. 
Model Calibration 57

Table 9. Estimates of hydraulic properties, expected intervals, and 95-percent confidence intervals 

for calibrated steady-state models of groundwater flow, Idaho National Laboratory and vicinity, 

Idaho.

[Hydraulic conductivity measured in feet per day. Values in italic indicate parameter is fixed, not estimated. 

Abbreviations: HC, hydraulic conductivity; VANI, ratio of horizontal to vertical hydraulic conductivity, 

dimensionless; –, not used in parameter structure]

Hydraulic 

property 

parameter

Expected 

interval

Parameter structure

No 

sediment

Whitehead 

sediment

Big Lost Trough 

sediment

Big Lost Trough 

sediment

Estimated value

95-percent 

confidence interval

Lower 

limit

Upper 

limit

Lower 

limit

Upper 

limit

Parameters corresponding to hydrogeologic zones where the presence of 

sediment does not affect hydraulic property estimates

HC1 0.01 24,000 296 1,870 11,700 10,200 13,500

HC2 6.5 1,400 8,240 5,530 384 244 610

HC3 .32 24,000 308 365 435 377 500

HC4 .32 24,000 288 – 9,890 1,730 54,700

Parameters corresponding to hydrogeologic zones where the presence of 

sediment does affect hydraulic property estimates

HC11 0.01 24,000 – 231 227 179 296

HC111 .01 24,000 – 512 – – –

HC22 6.5 1,400 – 25,422 4,780 3,610 6,140

HC222 6.5 1,400 – 676 – – –

HC44 .32 24,000 – 86 285 225 365

HC444 .32 24,000 – 459 – – –

Parameters corresponding to hydrogeologic property constant throughout the model domain

VANI 30 1,700 4,720 5,600 14,800 7,550 29,100

Table 10. Statistical measures related to parameter uncertainty and overall goodness of model fit 

for steady-state models of groundwater flow, Idaho National Laboratory and vicinity, Idaho.

[All statistics dimensionless. Abbreviations: HC, hydraulic conductivity; VANI, ratio of horizontal to vertical hydraulic 

conductivity; R2

N, correlation coefficient between ordered weighted residuals and normal order statistics]

Statistic

Parameter structure

No sediment Whitehead sediment Big Lost Trough 

sediment

Sum of squared weighted residuals 12,311 7,012 6,082

Average weighted residual 1 .74 .30 .51

Parameter correlation coefficients 2 HC3 VANI = 1.00 HC1 HC2 = -0.94 HC3 VANI = 0.92

Standard error of the regression 7.93 6.03 5.61

R2

N .945 .960 .954

Modified Beale's measure 6.98 5.85

1

 Positive average weighted residual indicates that, on average, weighted observed values were greater than weighted 

simulated values.

2

 Parameter correlation coefficients greater than 0.90.
58 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Estimates of Hydraulic Conductivity and 

Vertical Anisotropy

For the calibrated Big Lost Trough steady-state model 

the estimated values of HC parameters ranged from 227 to 

11,700 ft/d and the estimated value for VANI was 14,800 

(table 9; fig. 21). Confidence in these estimated parameter 

values was evaluated by (1) comparing the estimated values 

with expected values, (2) identifying whether parameters 

were estimated uniquely, (3) examining linear confidence 

intervals for the parameters, and (4) identifying if parameters 

were significantly influenced by a single observation. All 

parameters were log transformed in the calibration process; 

the distribution and uncertainty of parameters are often best 

represented by a log-normal probability distribution (Anderson 

and Woessner, 1992, p. 261; Hill and Tiedeman, 2007, p. 78) 

so comparisons are best made by viewing the parameters on a 

logarithmic axis as used on figure 21.

All the estimated HC parameter values were in the high 

end of the range of expected values (greater than the geometric 

midpoint) for their corresponding hydrogeologic units 

(fig. 21) (Ackerman and others, 2006, table 2). All estimates 

were nearly within 2 orders of magnitude of the maximum 

expected value in a range that exceeds 6 orders of magnitude. 

The estimated values are more consistent with the larger 

expected values of HC parameters derived from large-scale 

aquifer tests than smaller values of HC parameters derived 

from small-scale aquifer tests (table 11). The large-scale tests 

where discharge was greater than 0.52 ft3/s, were open to 

longer well intervals, and intersected more interflow zones. In 

contrast, the small-scale aquifer tests, which were slug tests or 

straddle-packer tests, with small stresses, were open to smaller 

intervals, and intersected fewer interflow zones (Welhan and 

others, 2002, p. 255). Because of the small stress applied and 

the short interval of the well isolated, the slug and straddlepacker tests characterized only a small volume of rock within 

a few feet of the well. Consequently, the large-scale tests 

better represent the magnitude of hydraulic conductivity at the 

scale of the flow model. 

The larger value for HC22 (4,780 ft/d, table 9; fig. 21) 

relative to HC2 (384 ft/d) and one-half an order of magnitude 

larger than the upper limit of the expected range of values 

(1,400 ft/d) is not readily explained. With the exception 

of hydrogeologic unit 2, estimated values of hydraulic 

conductivity for zones corresponding to a hydrogeologic 

unit were larger outside, and smaller inside, the region of 

abundant sediment. The smaller values for HC parameters 

inside the region of abundant sediment were consistent with 

sediment deposition at the land surface between basalt flow 

events, with the deposited sediment filling void spaces and 

thereby reducing the hydraulic conductivity of the subsequent 

interflow zone and the underlying basalt. Because the estimate 

of HC22 unexpectedly was larger than the value for HC2, 

the estimate of HC22 may be more uncertain than most 

other HC parameter values. The concern about the estimated 

value for HC22 being larger than the expected range and the 

value being greater than HC2, however, is tempered by three 

considerations: (1) the relatively small population of fieldestimated values of hydraulic conductivity for hydrogeologic 

unit 2 (table 3) used to define this range, (2) the relatively 

small confidence interval for parameter HC2 (fig. 21), and 

(3) the values for HC22 and HC2 (hydrogeologic unit 2) are 

less than that of hydrogeologic unit 1 (Ackerman and others, 

2006, p. 20). 

Estimates of HC22 also may be influenced by the 

simple discretization of the area of abundant sediment. The 

influence of sediment content as implemented in the model is 

very coarse. All zones within the area of abundant sediment 

contain greater than 11 percent sediment, but may contain as 

much as 50 percent sediment (Ackerman and others, 2006, 

p. 22). Recent geostatistical modeling of sediment abundance 

in the upper 300 ft of the aquifer in the study area (Welhan 

and others, 2007, p. 25; Stroup and others, 2008) suggest 

methods for better spatial resolution of relative sediment 

abundance within the model layers and aquifer parameter 

zones. This information along with the use of multiplier arrays 

in MODFLOW-2000 (Harbaugh and others, 2000, p. 13) may 

provide a parameterization with more spatial resolution of 

hydraulic conductivity within zones of abundant sediment.

The estimated value of 14,800 ft/d for the VANI 

parameter exceeded its maximum expected value of 1,700 

by nearly an order of magnitude (table 9; fig. 21). The range 

of expected values of the ratios of horizontal and vertical 

conductivity are derived from the results of a few aquifer 

tests that sample only a few interflow zones within a 240 ft 

open interval (Wood and Norrell, 1996 p. 6-9, table 6‐2),

straddle-packer intervals of 15 to 21 ft of the aquifer at a 

distance of 2,600 to 4,200 ft from a production well (Fredrick 

and Johnson, 1996, p. 16, tables 4–8), or are exclusively in 

sediment (Spinazola, 1994, table 2). In contrast, estimated 

VANI represents the large-scale vertical anisotropy of 

the aquifer that results from the vertical isolation of high 

permeability interflow rubble zones by intervening layers of 

less permeable sediment and the dense interior of individual 

basalt flows. The estimate of VANI is only slightly greater 

than a range of 2,100 to 13,000 calculated by Welhan and 

others (2006, p. 26) derived from geostatistical analysis of 

sediment content and the scaling of hydraulic conductivity 

with sediment content.

Parameter correlation coefficients were used to evaluate 

parameter uniqueness. The largest parameter correlation 

coefficient was 0.92, between HC3 and VANI (table 10). This 

was smaller than the critical value of 0.95, and indicates that 

all the parameters were estimated uniquely.
Model Calibration 59

Figure 21. Estimated values of parameters with 95-percent confidence intervals and ranges of expected values 

for Big Lost Trough model of steady-state groundwater flow, Idaho National Laboratory and vicinity, Idaho. 

Minimum expected values of hydraulic conductivity parameters are less than 10 feet per day.

ID19-0164_GWflow_fig. 21

10

100

1,000

10,000

100,000

HC1 HC11 HC2 HC22 HC3 HC4 HC44 VANI

Parameter name

Hydraulic conductivity, in feet per day

10

100

1,000

10,000

100,000 Anisotropy ratio, dimensionless

Estimated value

Minimum expected

Maximum expected

Lower 95-percent confidence interval

Midpoint of expected range

Upper 95-percent confidence interval
60 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Table 11. Ranges and central values of hydraulic conductivity estimated from aquifer tests, Idaho National Laboratory and vicinity, Idaho. [Hydraulic conductivity is bulk average hydraulic conductivity in feet per day, averaged over total open, perforated, or test interval length. Values are rounded to two significant figures. Anisotropy: Ratio of horizontal to vertical hydraulic conductivity; Abbreviations: M, multi-well pumping test; S, single well pumping test; SC, specific capacity pumping test; P, piezometer test; n, number of observations; t, number of tests; w, number of observation wells for multi-well tests; TC, type curve; R, regression analysis; I, iterative solution of equation; NS, numerical simulation; B, basalt; S, sediment; SB, sediment and basalt; INL, Idaho National Laboratory; NE, northeast of INL and East or North of Mud Lake; TAN, Test Area North; ft/d, foot per day; ft3/s, cubic foot per second] Data set Count Hydraulic conductivity (ft/d) Anisotropy Test type Analysis method Rock type Location Minimum First quartile Median Geometric mean Third quartile Maximum Medium- to high-capacity irrigation, industrial supply, and test wells (generally 0.7–13 ft3/s)

1 n = 15, t = 6, 

w = 1 or 2

600 790 2,900 2,800 13,000 18,000

M TC INL

2 n = 10 37 170 520 440 1,100 3,500 S TC INL

3 n = 7, t = 3, 

w = 14, 6, 3

1,600 3,800 6,200 6,100 11,000 22,000

M TC SB NE

4 n = 4, t = 4, 

w = 4

3,300 3,600 4,300 4,200 5,000 5,200 140 to 1,700

M TC

B INL

5 n = 2, t = 1, 

w = 4

860 2,100 5,300 230

M NS

B INL

6 n = 4, t = 1, 

w = 4

12,000 16,000 18,000 18,000 21,000 24,000 30, 60, 100

M TC

B INL

7 n = 2, t = 1, 

w = 2

140 330 35, 220

M TC S NE

8 n = 36 1 200 1,200 3,200 16,000 SC I B NE

9 n = 10 20 600 1,500 4,900 12,000 SC I SB NE

10 n = 6 10 300 780 1,300 3,000 SC I S NE

Low- to medium-capacity industrial supply and test wells (generally 0.01–0.1 ft3/s; 30 wells 0.52–9.7 ft3/s)

11 n = 114 0.01 14 360 130 2,000 24,000 S TC, R INL

Slug-test data for open intervals or straddle packer intervals for 30 wells

12 n = 59 0.23 3.6 26 17 120 700

P TAN

Medium- to high-capacity tests (values less than 0.52 ft3/s excluded)

213 n = 72 1.1 220 1,100 900 5,300 24,000 INL

1 Range for 61 estimates corresponding to 22 straddle-packer settings in 4 observation wells.2 Data sets 1, 2, 3, 4, 5, 6, 7, and a subset of data set 11 where values of pump discharge were greater than 0.52 ft3/s.

References for data sets 1 through 12:

1, 2 Mundorff and others, 1964, table 10. 7 Spinazola, 1994, table 2.3 Mundorff and others, 1964, p. 155. 8, 9, 10 Spinazola, 1994, fig. 35.4 Frederick and Johnson, 1996, tables 4–8. 11 Anderson and others, 1999, table 2.5 Frederick and Johnson, 1996, table 11, p. C3. 12 Welhan and Wylie, 1997; Welhan and others, 2002, table 1.6 Wood and Norrell, 1996, table 6-2.
Model Calibration 61

With the exceptions of HC22, HC4, and VANI, all 

parameters had 95 percent linear confidence intervals that 

were contained within the upper half of the range of expected 

values (fig. 21). The largest confidence interval (indicating 

larger uncertainty) was for HC4, and only part of the 

confidence interval exceeded the maximum expected value. 

A larger confidence interval also was indicated for parameter 

VANI, and the entire confidence interval was larger than 

the maximum expected value for this parameter. The linear 

confidence intervals were calculated assuming independent 

and normally distributed errors and model linearity, but some 

of the statistical measures do not support this assumption, 

which reduces the accuracy of the confidence intervals. The 

independence and normality of the weighted residuals were 

evaluated by plotting the ordered weighted residuals against 

the standard normal statistic and computing the associated 

correlation coefficient, R2

N. On the normal probability graph, 

the weighted residuals do not form a straight line (fig. 22), 

which indicates that the residuals deviate from a normal 

distribution. This is consistent with the R2

N value of 0.954, 

which was smaller than the critical value of 0.987 (at the 

0.05 significance level), below which residuals are not likely 

independent or normally distributed. The linearity of the 

model was evaluated using the modified Beale’s measure. The 

calculated value of 5.85 (table 10) is larger than the critical 

value for moderate nonlinearity of 0.5, and indicates that the 

model is highly nonlinear. The non-normal distribution of the 

weighted residuals and the nonlinearity of the model indicate 

that the calculated intervals should be considered approximate 

confidence intervals for the parameters.

The influence of specific steady-state head observations 

on estimated parameter values was evaluated with Cook’s D. 

Twenty-four head observations had Cook’s D values larger 

than the critical value of 0.02 and thus had the most influence 

on the set of estimated parameter values. Three observations 

(TANCH2B_401, USGS7_1280, and USGS13_781) had 

Cook’s D values larger than 0.2 (table 12), and each of these 

observations were omitted, separately, from the observation 

data set and the model was recalibrated. In each of the three 

Figure 22. Normal probability plot for Big Lost Trough 

model of steady-state groundwater flow, Idaho National 

Laboratory and vicinity, Idaho.

ID19-0164_GWflow_fig. 22

Weighted residual, dimensionless

Standard normal statistic, dimensionless

-3

-2

-1

0

1

2

3

-25 -20 -15 -10 -5 0 5 10 15 20 25

Table 12. Summary of observations and corresponding parameters with highest values of influence 

measures for steady-state model of groundwater flow, Idaho National Laboratory and vicinity, Idaho.

[Critical values for Cook’s D and DFBETAS were 0.020 and 0.141, respectively. Parameter associated with DFBETAS 

statistic. Re-calibrated parameter values result from omitting the observation for recalibration; Abbreviations: HC, 

hydraulic conductivity; ft/d, foot per day]

Observation Cook's D Parameter DFBETAS

Hydraulic conductivity

Base case model 

(ft/d)

Recalibrated model 

(ft/d)

TANCH2B_401 1.01 HC4 2.17 9,890 4,910

HC44 -1.84 285 329

USGS7_1280 .34 HC4 1.33 9,890 5,260

USGS13_781 .23 HC2 1.34 384 323

recalibrations no parameter correlations were larger than 

0.93, values for the sum of squared residuals were similar, 

and parameter values did not change substantially except for 

HC4 (table 12). These large changes in the value of HC4 are 

consistent with the large uncertainty in this parameter estimate 

(fig. 21). With the exception of HC4, the large number of 

observations seems to have reduced the likelihood of a single 

observation being influential to the set of parameters.
62 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Although most parameter values were within acceptable 

ranges, the unexpectedly large parameter estimates for HC22 

and VANI, and the large confidence intervals for HC4 and 

VANI that were in part or wholly outside the expected range 

(table 9; fig. 21) allow for a ranking of the confidence in the 

parameter estimates for the calibrated model. Utilizing the 

calibrated parameter estimates and the criteria discussed in this 

section, greater confidence is warranted for parameters HC1, 

HC11, HC2, HC3, and HC44 than for HC22, HC4, and VANI. 

The lower confidence in parameter HC4 also is consistent with 

the low CSS for HC4 (fig. 20). 

Comparison of Simulated and Observed 

Steady-State Heads

Model simulation results also were evaluated based 

on the agreement between simulated and observed heads. 

Evaluations included (1) a visual comparison of the altitudes 

and shapes of the simulated and observed water tables based 

on 50-ft contour maps of the water table, (2) qualitative 

comparisons of vertical gradients and vertical flow directions 

based on simulated heads and piezometer head measurements 

and intraborehole flowmeter surveys, and (3) quantitative 

comparisons based on the statistical and spatial distributions 

of weighted residuals for heads.

Simulated equivalents to observed heads were calculated 

by MODFLOW-2000 using spatial interpolation in the 

horizontal plane and calculation of multilayer heads for wells 

open to multiple model layers (Hill and others, 2000, p. 

31-35). Multilayer heads were calculated by specifying a head 

contribution from each model layer that is in proportion to the 

transmissivity of the open interval in that layer.

Altitudes and Shapes of Simulated and Observed Water Table

The simulated water-table map was constructed from 

30,983 simulated heads distributed uniformly throughout the 

model area. These heads were in model layer 1 at the center 

of each grid cell (the equivalent of 16 simulated heads per 

1 mi2). The observed water-table map (Lindholm and others, 

1988) was constructed from 66 head observations distributed 

non-uniformly throughout the model area (the equivalent of 

1 head observation per 29 mi2). Approximately 45 additional 

head observations, outside of the model area, were used to 

infer the orientation and altitude of water-table contours near 

model boundaries. Head information available to construct 

the simulated water-table map was about 470 times more 

abundant than that used to construct the observed water-table 

map, thus the spatial resolution of the simulated water-table 

map is much finer than that of the observed water-table map. 

The simulated water-table map should not be considered 

better than the observed water-table map simply because it 

has a value for each model cell. Construction of the observed 

water-table contour map for the entire model area required 

considerable interpolation and extrapolation, particularly 

along the northwest mountain-front boundary and within 

the southwest one-third of the model area where fewer 

head observations were available in 1980 (figs. 4D and 8). 

Water‐table contours, contour interval 50 ft, were extrapolated

and drawn to reflect the conceptual character of the model 

boundaries. For example, water-table contours were drawn 

perpendicular to boundaries or segments of boundaries that 

were conceptualized as no-flow boundaries and parallel or 

sub-parallel to boundaries or segments of boundaries that were 

conceptualized as inflow or outflow boundaries. 

The water-table contour maps indicate that the 

steady‐state model simulation was able to reasonably

reproduce observed altitudes, orientations, and gradients 

within the central and northeastern part of the model area 

where the quality of the head measurements is the most 

reliable and their spatial density highest. The water-table 

contour maps also indicate where head observations were 

weighted in a manner to exert maximum influence on the 

outcome of model simulations (fig. 23). 

Near the northern boundary of the INL, the simulated 

4,600 ft altitude of the water table is about 20 ft higher than 

interpolated water levels from the observed water-table map 

(fig. 23). Head observations used for calibration in this area 

are relatively abundant in and around TAN, but are lacking 

in the immediate vicinity of Birch Creek and the nearby part 

of the northeast inflow boundary (figs. 4D and 8). Although 

head observations were more abundant in the TAN area, the 

distribution was not sufficient to result in improved agreement 

between the simulated and observed heads in this area because 

of the lack of head observations near the Birch Creek and 

northeast inflow boundaries. The orientation of the simulated 

4,600 ft contour reflects a complex interplay of inflow from 

the Birch Creek alluvial aquifer to the northwest, regional 

aquifer underflow and infiltration from irrigation return 

flows along the northern end of the northeast boundary, and 

infiltration from Birch Creek (figs. 14 and 18).

The simulated altitude of the water table near the Little 

Lost River inflow boundary may be 50 ft higher than indicated 

by the observed water-table map (fig. 23) and associated 

observations. Near the mouth of the Little Lost River the 

simulated water-table contours reflect the combined effects 

of inflow to the aquifer from the alluvial fill of the Little Lost 

River; infiltration from the Big Lost River Sinks, Playas, and 

channel; and infiltration from irrigation return flows east and 

south of Howe (figs. 14 and 18). Head observations are sparse 

in this area, many were from wells open to multiple layers, 

and were insufficient to resolve the local effects of these 

aquifer inflows on the altitude and shape of the observed water 

table in this area. 
Model Calibration 63

Figure 23. Observed and simulated water table for 1980 showing relation to hydrogeologic zones in layer 1 for Big Lost 

Trough model of steady-state groundwater flow, Idaho National Laboratory and vicinity, Idaho.

ID19-0164_GWflow_fig. 23

Model area boundary

4500

4550

Water-table contour—Shows altitude of water table in March 

1980. Interval 50 feet. Dashed where approximately located. 

Datum is NGVD 29. Modified from Linholm and others, 1988.

Simulated 1980 water-table contour—Shows altitiude of 

water-table contour from steady-state simulation. Interval 50 

feet. Datum is NGVD 29.

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

spreading areas

A, B, C, and D

Little Lost River

Birch

Creek

Mud Lake

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

4400

4300

4350

4250

4450

4200

4500

4150

4100

4500

4600

4600

4550

4600

4450 4450

4600

4650

4700

4550

4400

4350

4400

4500

4300

4250

4200

4150

4750

4100

4500

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

EXPLANATION

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

1—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally less than 11 percent

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally less than 11 percent

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

4—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

11—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally more than 11 percent

22—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

44—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

6—Silicic rocks, including rhyolite domes and andesite

 Hydrogeologic zones, model layer 1

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.
64 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

The simulated altitude of the water table near the 

Big Lost River inflow boundary may be 50 ft higher than 

indicated by the observed water-table map (fig. 23) and one 

observation. The altitude of the water table near the mouth of 

the Big Lost River valley is defined by a single observation 

well open to layers 2 and 3 (Weaver and Lowe, table A1), 3 

mi southwest of where the Big Lost River enters the model 

area (fig. 4D). This distant single observation with a very 

low weight (WeavLow_585, table G1) did not restrain the 

simulated water-table altitudes rising to 4,600 ft and higher 

near the mouth of the Big Lost River; however, the shapes of 

the simulated and observed water table are similar. 

In the southwest one-third of the model area, simulated 

and observed water-table altitude differences vary from 0 ft 

to as much as 115 ft. Ten head observations scattered over an 

area of about 650 mi2 were used for calibration (fig. 4D). The 

shape of the interpreted observed water-table contours within 

the southwest one-third of the model area indicates a tendency 

for groundwater to flow toward the center and southeast 

section of the southwestern boundary, whereas the simulated 

water-table contours show a more uniform flow field with 

limited tendency for flow to move preferentially towards the 

center of the southwest boundary. 

Simulated and Observed Vertical Gradients and 

Vertical Flow Directions

Simulated and observed vertical gradients generally are 

larger than horizontal gradients; however, flow in the aquifer 

is predominately horizontal. Observed horizontal gradients 

at the water table typically range from 0.0002 to 0.002 

(Ackerman and others, 2006, p.39) although gradients may be 

as great as 0.01 at the northeastern boundary or 0.02 near the 

mountain-front boundary (Barraclough, Teasdale, and Jensen, 

1967, p. 22). Measured vertical gradients in the upper 500 ft 

of the aquifer at two sites in the northeast corner of the INL 

(table 13) were as large as 0.03 upward and 0.007 downward. 

Vertical gradients at well Highway 1 (table A1; fig. B2) 10 mi 

east of the study area are between 0 and 0.0009 downward. 

Measurement of head gradients was attempted at wells USGS 

44, 45, 46, and 59 (table A1; fig. B7) during straddle-packer 

tests in 1992–94 (Frederick and Johnson, 1996). However, 

the measurements were below the detection limit of the 

equipment, which for head differences across the packers, may 

have been about 0.1 ft (G.S. Johnson, University of Idaho, 

oral commun., 2004). This corresponds to gradients of ±0.05. 

These locations are the extent of measurements of vertical 

gradients in and near the study area. The average simulated 

vertical gradient between model layers in the upper five layers 

(800 ft) of the aquifer was 0.04 downward. Seventy-five 

percent of simulated vertical gradients in the upper five layers 

were between 0.12 downward and 0.01 upward.

Vertical gradients and flow directions were simulated 

for the ESRP aquifer, but because there are few wells in the 

model area where vertical gradients or flow directions have 

been observed, comparisons are limited between simulated 

results and observations. The direction of vertical flow in the 

upper 300 ft (model layers 1–3) of the aquifer was measured 

at 12 wells (13 intervals) during 1963–65, 1 well (3 intervals) 

during 1980, and 3 wells during 1991 (table 13). Eleven of 

these wells are at the INTEC, and the other five wells are 

southeast of TAN, north of the NRF, and at the RTC (table 13; 

fig. 1; appendix B). Flow between model layers 1 and 2 in 

wells at the INTEC and the deepest piezometer pair at USGS 

30 was between hydrogeologic zones 11 and 22; flow at the 

other wells was within a single hydrogeologic zone (table 13). 

In the northeast part of the model area, vertical directions 

and gradients were measured at wells USGS 30 and USGS 4 

(fig. 1); model simulation results disagree with most of these 

measurements. At USGS 30, near the northeast corner of the 

INL, nested piezometers are in model layers 1, 2, and 4; the 

two shallower piezometers are in hydrogeologic zone 11, and 

the deepest piezometer is in hydrogeologic zone 22. Observed 

gradients in 1980 were 0.019 to 0.022 upward between the 

middle and upper piezometers and 0.027 to 0.031 upward 

between the lower and upper piezometers (table 13); the 

corresponding simulated gradients were 0.0002 downward 

and 0.044 upward, respectively. At well USGS 4, downward 

flow between intervals about 50 and 150 ft below the water 

table was measured using a trace-ejector survey in 1964. In 

November 1965, an inflatable packer separating these two 

intervals was installed in the well, and head measurements 

made through 1966 showed a downward gradient between 

these intervals ranging from 0.001 to 0.007 (Morris and 

others, 1965, p. 43-44; Barraclough, Teasdale, and Jensen, 

1967, p. 45-47; and Barraclough, Teasdale, and others, 1967, 

p. 88-90). The 1980 simulated gradient between model 

layers 1 and 2 at this location, which was entirely within 

hydrogeologic zone 1, was 0.003 upward.

Simulated and observed flow directions agreed at 

wells USGS 30, USGS 51, USGS 59, and Site 17, where 

simulated gradients between layers were larger than 0.01 

(table 13). Where simulated gradients between model layers 

were less than 0.01, only 4 of the 13 wells had simulated and 

observed flow directions that agreed. Discrepancies between 

simulated and observed flow directions may be partly due 

to the temporal separation of observed flows (1963–65 and 

1991) and simulated flows (1980), to intermittently operating 

production and injection wells at site facilities during the 

period of 1950–80, and to model limitations and error.
Model Calibration 65

Table 13. Observed and simulated steady-state vertical directions and gradients of groundwater flow in open boreholes, 

piezometer nests, and packer-isolated intervals of boreholes, Idaho National Laboratory, Idaho.

[Gradient: Values are dimensionless; simulated gradient was interpolated at well locations within model grid cells. Reference: A, Morris and 

others, 1964, p. 40-42; B, Morris and others, 1965, p. 42-44; C, Barraclough, Teasdale, and Jensen, 1967, p. 94-98; D, Barraclough and others, 1967, 

p. 88-90; E. Morin and others, 1993, table 1. Abbreviations: Pack, temporary packer completion; Piez, piezometer nest; TE, trace ejector; TF, thermal 

flowmeter; –, no information]

Date Well name

Direction of flow Gradient Corresponding model

Method Reference

Observed Simulated Observed Simulated Layers Zones

Northeast Idaho National Laboratory and Southeast of Test Area North

1964 USGS 4 Down Up – 0.003 1 and 2 1 TE B

1966 USGS 4 Down Up 0.001 to 0.007 .003 1 and 2 1 Pack D

1980 USGS 30 Up Down 10.019 to 0.022 .0002 1 and 2 11 Piez 

1980 USGS 30 Up Up 10.027 to 0.031 .044 2 and 4 11, 22 Piez 

1963 USGS 31 Up Down – .007 1 and 2 11 TE A

Idaho Nuclear Technology and Engineering Center

1965 USGS 42 Up Up – 0.001 1 and 2 11, 22 TE C

1965 USGS 43 Static Up – .001 1 and 2 11, 22 TE C

1991 USGS 44 Up Up – .001 1 and 2 11, 22 TF E

1991 USGS 45 Up Up – .002 1 and 2 11, 22 TF E

1991 USGS 46 Up 2 Down – .001 1 and 2 11, 22 TF E

1963 USGS 47 Up Down – .003 1 and 2 11, 22 TE A

1965 USGS 48 Static 3 Up – .005 1 and 2 11, 22 TE C

1965 USGS 48 Down 3 Up – .008 2 and 3 22 TE C

1965 USGS 49 Down 3 Up – .006 1 and 2 11, 22 TE C

1965 USGS 51 Up Up – .011 1 and 2 11, 22 TE C

1965 USGS 52 Up 4 Up – .004 1 and 2 11, 22 TE C

1965 USGS 59 Up 4 Up – .012 1 and 2 11, 22 TE C

North of Naval Reactors Facility

1964 Site 17 Down Down – 0.013 1 and 2 11 TE B

Reactor Technology Complex

1964 MTR test Down 5 Up – 0.006 1 and 2 22 TE B

1

 Observed 1980 range of gradients, water-level data are from http://nwis.waterdata.usgs.gov/id/nwis/gwlevels.

2

 Observed gradient is down when nearby production well is pumping.

3

 Observed direction may be influenced by nearby injection well.

4

 Observed direction may be influenced by nearby injection or production wells.

5

 Observed direction may be influenced by nearby infiltration pond.
66 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Simulated vertical gradients just downgradient of the 

INTEC were generally upward from model layers 3 and 2 

toward layer 1. This area of upward flow is coincident with 

the southwest boundary of the Big Lost Trough (figs. 7B

and 23). Large downward gradients, greater than 0.05, in the 

upper 300 ft of the model were coincident with the southwest 

boundary of hydrogeologic zones 1 and 2. Other areas where 

larger, greater than 0.2, downward gradients were simulated 

include (1) near the mouth of the Big and Little Lost River 

valleys in the upper 300 ft of the aquifer and (2) throughout 

most of the southwestern part of the INL and south of the INL 

below an aquifer depth of 400 ft (model layer 4 and below).

Although vertical gradients are larger than horizontal 

gradients, simulated flow in the aquifer is predominantly 

horizontal. For example, horizontal fluxes along rows 

in hydrogeologic zone 1, model layer 1, averaged 1,500 

(ft3/s)/mi2 in a southwest direction, with 75 percent of the 

values between 880 and 1,900 (ft3/s)/mi2. Vertical fluxes 

across the bottom cell faces of the same zone and layer 

averaged 2.1 (ft3/s)/mi2 for cells with downward flow and 

1.9 (ft3/s)/mi2 for cells with upward flow. Vertical flow in the 

aquifer is restricted by relatively impermeable subhorizontal 

layers of dense basalt and sediment, and the restriction 

that these stratigraphic layers impose on vertical flow is 

represented in the calibrated model with a large value for the 

vertical anisotropy (VANI) of the aquifer (table 9).

Statistical and Spatial Distributions of 

Weighted Head Residuals

Separate illustrations of the graphical (fig. 24A) 

and spatial (fig 25A) distributions of weighted residuals 

corresponding to wells only in model layer 1, which contains 

the water table, are presented separately from wells not 

exclusively in layer 1 (figs. 24B and 25B). Separating the 

two groups enables comparisons of model performance for 

(1) wells most representative of water-levels at and near the 

water table and (2) wells in multiple model layers or in layers 

other than layer 1 that provide information on head differences 

with depth. All weighted residuals are shown in figures 24C

and 25C.

Weighted residuals were plotted against weighted 

simulated equivalents in order to evaluate if the weighted 

residuals were randomly distributed. For the 105 wells open 

only to model layer 1, the distribution of weighted residuals 

was fairly evenly and uniformly distributed around zero 

(fig. 24A). There was a slight negative (simulated values 

greater than observed values) bias for these residuals, 

however, and the average value of the weighted residuals was 

-0.30. 

For the 96 wells that were open to more than just 

model layer 1, the distribution of weighted residuals shows 

a positive (simulated values less than observed values) bias 

(fig. 24B). The average value of the weighted residuals was 

1.41, including three larger values representing multi-layer 

completions, which also indicates that, on average, simulated 

heads were underestimated for model layers below layer 1. 

The model does not perform as well for estimating heads 

for multi-layer completions. The model also may be poorly 

constrained for estimating heads at depth in the aquifer. 

Uneven spatial distribution of wells and boreholes vertically 

has been mentioned in the Conceptual Model section as a 

data limitation for the study. The simulations of heads at 

depth, vertical gradients, and vertical flow directions could be 

improved in the study area with the collection of additional 

head data at multiple levels in the aquifer.

The average value for all 201 weighted residuals 

(fig. 24C) was 0.52 with nearly equal numbers of larger 

negative and positive residuals (absolute value of residual 

greater than 1 standard error of the regression). The weighted 

residuals generally are evenly distributed about zero with 

the exception of a slight positive bias for weighted simulated 

values around 2,200 and a slight negative bias around 

weighted simulated values of 4,400. For comparison and ease 

of visualization, weighted residuals also were plotted against 

(unweighted) simulated values (fig. 24D). 

The weighted residuals were plotted on maps of the 

model area (fig. 25) to evaluate further if they were randomly 

distributed. The overall distribution of the weighted residuals 

seems random, although some small areas have clusters of 

either negative or positive residuals and larger areas have 

possible patterns of larger residuals, indicating that the model 

fit to observed data is locally not as good.

Most clusters of negative and positive weighted residuals 

are near facilities where data density is highest and weighted 

residuals tend to be small in absolute value at these locations. 

This clustering likely is caused by representing hydraulic 

conductivity with a uniform value throughout a hydrogeologic 

zone. This is a consequence of the parameterization of the 

model.

In the northern part of the INL, an area at and 2 mi 

southeast of TAN includes a cluster of small positive weighted 

residuals for all wells (fig. 25A, B). The model error indicated 

by this cluster of positive residuals might be small because all 

but two of these residuals had a value that was less than 1s, 

the standard error of the regression. This particular cluster, 

however, is part of a larger trend from negative to positive 

weighted residuals in the area from 5 mi northwest to 2 mi 

southeast that results from the model simulating a horizontal 

gradient of about 0.0001–0.001 in an area with the lowest 

observed water-table gradient, 0.0002, in the study area 

(Ackerman and others, 2006, p. 39). Poor model fit in this area 

is likely related to difficulty in assigning hydrogeologic zones 

for an area with poor stratigraphic control. Model fit also may 

not be as good in this area because many of these observations 

were from periods other than 1980.
Model Calibration 67

ID19-0164_GWflow_fig. 24A

A.

Weighted residual, dimensionless

Standard error of the regression, dimensionless

Weighted simulated value, dimensionless

1s

-1s

-2s

2s

3s

4s

-3s

-4s

0 1,000 2,000 3,000 4,000 5,000 -25

-20

-15

-10

-5

0

5

10

15

20

25

EXPLANATION

Note: Positive residual indicates that the weighted observed 

value is greater than the weighted simulated value.

Weighted head residual—in terms of s, standard error of the 

regression

Figure 24. Weighted residuals as a function of weighted simulated values of head for (A) wells open 

exclusively to model layer 1, (B) wells not open exclusively to layer 1, (C) all wells, and (D) weighted 

residuals as a function of simulated values for Big Lost Trough model of steady-state groundwater flow, 

Idaho National Laboratory and vicinity, Idaho.
68 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 24B

B.

Weighted residual, dimensionless

Weighted simulated value, dimensionless

Standard error of the regression, dimensionless

1s

-1s

-2s

2s

3s

4s

-3s

-4s

0

0 1,000 2,000 3,000 4,000 5,000 -25

-20

-15

-10

-5

0

5

10

15

20

25

EXPLANATION

Note: Positive residual indicates that the weighted observed 

value is greater than the weighted simulated value.

Weighted head residual—in terms of s, standard error of the 

regression

Figure 24.—Continued.
Model Calibration 69

ID19-0164_GWflow_fig. 24C

C.

Weighted residual, dimensionless

Weighted simulated value, dimensionless

Standard error of the regression, dimensionless

1s

-1s

-2s

2s

3s

4s

-3s

-4s

0

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

EXPLANATION

Note: Positive residual indicates that the weighted observed 

value is greater than the weighted simulated value.

Weighted head residual—in terms of s, standard error of the 

regression

-25

-20

-15

-10

-5

0

5

10

15

20

25

Figure 24.—Continued.
70 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 24D

D.

Weighted residual, dimensionless

Standard error of the regression, dimensionless

1s

-1s

-2s

2s

3s

4s

-3s

-4s

0

-25

-20

-15

-10

-5

0

5

10

15

20

25

4,100 4,200 4,300 4,400 4,500 4,600

Simulated value, in feet

Note: Positive residual indicates that the weighted observed 

value is greater than the weighted simulated value.

Weighted head residual—in terms of s, standard error of the 

regression

Figure 24.—Continued.
Model Calibration 71

ID19-0164_GWflow_fig. 25A

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

USGS 23

SITE 2

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Model area boundary

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North Note: Positive residual indicates that the weighted observed 

value is greater than the weighted simulated value.

Less than -2s

-2s to -1s

-1s to 0

0 to 1s

1s to 2s

Greater than 2s

Weighted head residual—in terms of s, standard error of the 

regression

Mud Lake

A.

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

EXPLANATION

Figure 25. Distribution of weighted residuals of head for (A) wells open exclusively to model layer 1, (B) wells not open 

exclusively to model layer 1, and (C) all wells for Big Lost Trough model of steady-state groundwater flow, Idaho National 

Laboratory and vicinity, Idaho.
72 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 25B

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Model area boundary

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North Note: Positive residual indicates that the weighted observed 

value is greater than the weighted simulated value.

EXPLANATION

Less than -2s

-2s to -1s

-1s to 0

0 to 1s

1s to 2s

Greater than 2s

Weighted head residual—in terms of s, standard error of the 

regression

Mud Lake

B.

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

Figure 25.—Continued.
Model Calibration 73

ID19-0164_GWflow_fig. 25C

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Model area boundary

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North Note: Positive residual indicates that the weighted observed 

value is greater than the weighted simulated value.

EXPLANATION

Less than -2s

-2s to -1s

-1s to 0

0 to 1s

1s to 2s

Greater than 2s

Weighted head residual—in terms of s, standard error of the 

regression

Mud Lake

USGS 23

SITE 2

C.

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

Figure 25.—Continued.
74 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

The largest weighted residuals generally are in areas 

mentioned in the section Altitude and Shapes of Simulated and 

Observed Water Table. The largest positive weighted residual 

in the model, 20.4 for well USGS 23, was near the mouth 

of the Little Lost River valley (fig. 25A). Poorer model fit at 

this location was a result of few water-level data available 

to constrain the simulated water table and few geologic data 

available to constrain the conceptualization of the complex 

geologic transition from shallow mountain-valley aquifers 

to the deeper ESRP aquifer. Water levels from just one well 

near the mouth of the Big Lost River valley and from only a 

few wells near the mouth of the Little Lost River valley were 

available for contouring water levels and changes in gradient 

in these areas. Large weighted residuals resulted from the 

inability to represent the complex hydrogeology accurately 

near the mouths of these tributary valleys.

The four largest negative residuals (fig. 25A) are scattered 

throughout the aquifer, but the largest negative residual, 

-22.4 at well Site 2, is southwest of the INL half way to the 

southwest border. In the southwest one-third of the model area 

all maps show a broad area of positive weighted residuals. 

The model error reflected by this area of positive residuals 

is a result of the limited geologic and water-level data for 

this area. The uniform estimated value for HC3 in this area 

strongly influenced the simulated water table, which had a 

fairly uniform gradient to the southwest of the INL (fig. 23). 

This is in contrast to the water-table gradients estimated from 

field observations, which ranged from steep to moderately flat 

(fig. 23).

In the southeast corner of the INL near the southeast 

boundary of the model area (fig. 25) scattered values of 

dominantly negative weighted residuals may indicate a 

possible bias toward higher simulated values in this area, but 

most values are relatively small, between +1s and -1s.

Analysis of Alternative Model Conceptualizations 

A series of alternative model conceptualizations were 

evaluated to examine the effect of certain aspects of the 

conceptual model and numerical model characteristics 

and assumptions on the model simulation results. The 

calibrated Big Lost Trough steady-state model, or base 

case steady‐state model, was evaluated by examining the

response of the model to alternate implementations of the 

parameter structure, hydrogeologic framework, or boundary 

conditions. The initial comparison of different representations 

of the sediment content (parameter structures) was the first 

such analysis (tables 9 and 10; fig. 21). For the base case 

model, conceptualizations of two hydrogeologic framework 

alternatives and eight changes to boundary condition quantities 

and areas were evaluated. Eight of these alternative model 

analyses are compared quantitatively (table 14). The effects 

of the alternative representations primarily are quantified 

in relation to the base case values of hydraulic conductivity 

(HC) parameters. The implementation of the hydrogeologic 

framework in the conceptual model was examined using two 

modifications, which are supported by geologic evidence and 

alternative interpretations. Other than measured withdrawals 

or injection for industrial wells and infiltration of streamflow 

estimated from gaging station records, estimates of flux at 

model boundaries are indirect estimates from various sources. 

Some of these estimates of flux may be of greater importance 

than other estimates for calibration and the analysis of 

contaminant transport.

Thickness of Aquifer

The altitude of the base of the aquifer and aquifer 

thickness as interpreted from geophysical surveys (fig. 6) 

exceeds, in some areas, the values of altitude of the base of 

the aquifer and aquifer thickness derived from the few wells 

that penetrated the full aquifer thickness (fig. 4A). Alternate 

conceptualizations of the aquifer framework arise from using 

the geophysical surveys or from interpreting the data from 

the available data from deep wells. To test the sensitivity 

of the model to the aquifer thickness (alternative model 

A), the saturated thickness was set to a maximum of values 

(1,200 ft) interpreted from well information, (Anderson and 

Liszewski, 1997, p. 11). This adjustment limited the thickness 

of model layer 6 to 400 ft. The alternative model was similar 

in most calibration criteria and parameter values (table 14). 

Most estimated values for parameters were slightly smaller 

or larger. Parameter HC3 was greater than the base case 

value (27 percent different, 0.12 orders of magnitude) and 

outside the confidence interval for the base case model. This 

difference did not alter the dominance of horizontal flow in 

the uppermost part of the aquifer at the INL and downward 

flow downgradient of the INL. The model was not sensitive 

to a change in aquifer thickness where the depth to the base 

as interpreted from geophysical surveys was deeper than any 

thickness derived from borehole logs. Expensive drilling to 

gain additional data about the thickness of the aquifer would 

therefore not seem to be necessary for improving the model.

Domes and Buttes

Early in the calibration process using parameter 

estimation, the sensitivity of the model was evaluated for 

including the presence of a less permeable hydrogeologic 

unit near East and Middle Buttes corresponding to the 

intermediate composition rocks represented by parameter 

HC6. The presence in the aquifer of these rocks associated 

with the buttes is documented only in well Corehole 1 (fig. 1). 

Because of a slight improvement in calibration criteria, 

and because this change simulated an observed (Ackerman 

and others, 2006, p.22), albeit slight, deflection in the 
Model Calibration 75

Table 14. Regression statistics and estimated values of parameters for base case and alternative steady-state models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.

[Parameter values in foot per day except for VANI. Estimated parameter values for alternative models in bold are outside the confidence intervals for the 

calibrated model. Alternative model: A, thickness of the aquifer limited to largest value from well data; B, flow across NE bound × 1.2; C, Flow across NE 

bound × 0.8; D, flow across LLR bound × 1.2; E, flow across LLR bound × 0.8; F, flow from BLR × 0.85; G, SW bound head increases with depth; H, SW 

bound head decreases with depth. Abbreviations: LLR, Little Lost River; BLR, Big Lost River; VANI, ratio of horizontal to vertical hydraulic conductivity]

Regression statistics Base case 

model

Alternative model

A B C D E F G H

Sum of squared weighted residuals 6,082 5,742 6,144 6,050 6,017 6,238 6,068 6,111 6,052

Average weighted residual 0.51 0.53 0.55 0.50 0.52 0.56 0.51 0.52 0.53

Standard error of the regression 5.61 5.45 5.64 5.60 5.58 5.68 5.61 5.63 5.60

Estimated parameter values

Hydraulic 

property 

parameter

Calibrated 

value

95-percent 

confidence 

interval Estimated value

Lower 

limit

Upper 

limit

HC1 11,700 10,100 13,400 11,900 13,300 10,100 12,100 11,300 11,800 11,600 11,700

HC11 227 176 294 264 253 211 253 210 228 229 228

HC2 384 243 606 471 450 317 401 364 386 386 376

HC22 4,780 3,670 6,240 5,270 6,510 2,940 4,420 4,980 4,610 4,740 4,740

HC3 435 377 500 571 509 365 440 437 431 459 414

HC4 9,890 1,740 56,200 9,860 16,200 5,870 8,840 11,400 9,980 9,740 9,960

HC44 285 224 364 329 318 257 279 295 285 286 287

VANI 14,800 7,510 29,200 26,600 18,300 11,700 13,400 17,000 14,800 14,900 14,700

water‐table gradients in the area, the inclusion of the hydraulic

conductivity zone representing these rocks was adopted 

without further analysis in the calibrated model and in all 

alternative models.

Northeast Boundary Flux

The largest component of flow into the aquifer is across 

the northeast boundary. To assess the effect of uncertainty 

in the quantity of flow for this boundary condition, flow was 

increased (alternative model B) and decreased (alternative 

model C) by 20 percent and the alternative model was 

recalibrated. Multiplying the boundary flow by a factor of 

1.2 produced a recalibration that did not improve regression 

statistics compared to the base case model, and simulated 

higher hydraulic conductivities and VANI (table 14). 

Alternative model B values were well within the confidence 

intervals of the base case model except for parameters 

HC22 and HC3. Confidence intervals for HC22 and HC3 in 

alternative model B overlapped those of the base case model 

and alternative values were larger by 32 and 16 percent (0.14 

and 0.07 orders of magnitude), respectively. 

Multiplying the boundary flow by a factor of 0.8 

(alternative model C) resulted in a slight improvement in 

the sum of squared weighted residuals and lower simulated 

hydraulic conductivities and VANI compared to the base 

case scenario. Confidence intervals for parameters HC22 and 

HC3 overlapped those of the calibrated model and alternative 

values were smaller by 46 and 17 percent (0.20 and 0.08 

orders of magnitude), respectively. 

The model calibration is apparently sensitive to a 

decrease in the inflow along the northeast boundary. Of the 

estimates of flow entering the system in the model area, the 

underflow from the aquifer upgradient of the model area 

(northeast) is most important because the underflow has 

some measurable influence on parameter (hydraulic property) 

estimates. This change did not alter the dominance of 

horizontal flow in the uppermost part of the aquifer at the INL 

and downward flow down gradient of the INL. 
76 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Little Lost River Tributary-Valley Underflow

The Little Lost River tributary-valley underflow is 

positioned upgradient of and across the Big Lost River 

from the central area of concern for contaminant transport 

modeling. The confidence in the quantity of inflow across 

the boundary, estimated from basin budget analysis, is poor. 

In comparison, the estimates for the Big Lost River and 

Birch Creek tributary valleys are fair (Kjelstrom, 1986). 

To evaluate the potential sensitivity of the Little Lost River 

tributary‐valley underflow boundary condition, inflow was

increased (alternative model D) and decreased (alternative 

model E) 20 percent in a manner similar to that for the 

northeast boundary. Recalibration of the model with increased 

underflow from the Little Lost River valley improved the 

sum of squared errors and standard error of the regression. 

Alternative model D and E parameter values were smaller 

and larger than base case values (table 14). No alternative 

parameter values were outside of the confidence intervals 

for the base case parameters and all were within 0.05 order 

of magnitude of the calibrated values. Recalibration of the 

model with decreased underflow from the Little Lost River 

valley did not improve calibration criteria. No alternative 

parameter values were outside of the confidence intervals 

for the calibrated parameters, and all were within 14 percent 

(0.07 order of magnitude) of the base case values. Early in 

the calibration process using both trial-and-error analysis and 

parameter estimation, the distribution of underflow from the 

Little Lost River tributary valley aquifer was tested using 

different rates and proportions of flow among the model layers 

at the boundary. The simulations of underflow only to model 

layer 1 resulted in much higher heads in layer 1. Simulations 

with underflow in model layer 4 also were unsatisfactory 

due to poor model convergence. Limited water-table head 

data from Little Lost River Valley and sparse information 

on variations in head with depth hinder improvement of the 

model in this area.

Big Lost River Streamflow Infiltration Area

Local-scale experiments documenting horizontal 

movement of infiltration from the Big Lost River in the 

unsaturated zone of as much as 0.8 mi (Nimmo and others, 

2002) indicate that the discretization of infiltration may be 

better represented with an increased area of influence. Early in 

the calibration process using parameter estimation, the model 

was recalibrated with infiltration applied to areas increased 

by 1 and 2 mi from the areal traces of rivers or boundaries of 

spreading areas, sinks, and playas. No substantial change in 

parameter values was observed. No further evaluation was 

done for the calibration and sensitivity analysis for the model. 

Due to the cell size used for discretization, the implementation 

of the conceptual model inherently treats the area of influence 

for river channels with a minimum of 1,320 ft. River channel 

width in the model area averages 38 ft and ranges from 23 to 

48 ft (Nace and Barraclough, 1952, p. 15, table 5). Calibration 

of the steady-state model is insensitive to extending the 

footprint of the Big Lost River within the range of 0.25 to 

2 mi.

Big Lost River Infiltration and Evaporation

The steady-state infiltration of streamflow is a locally 

significant proportion of inflow to the aquifer (Ackerman 

and others, 2006, p. 33). The sensitivity of the model to 

reductions in estimates of infiltration from Big Lost River due 

to evaporation or inaccurate measurements (alternative model 

F) was estimated by recalibration with a 15 percent decrease 

in infiltration. The reduction of streamflow infiltration by 

evaporation losses was not considered in the conceptual 

model. Consideration of evaporation from the Big Lost River 

is included in the refinement of the conceptual model in the 

transient calibration.

A system-wide decrease of 15 percent in the total amount 

of infiltration from the Big Lost River, whether representing 

evaporation loss or error in estimating streamflow infiltration, 

does not have much influence on the calibrated values of 

hydraulic conductivity parameters. Alternative model F 

was nearly identical in calibration criteria and parameter 

values (table 14). No alternative model F parameter values 

were outside of the confidence intervals for the calibrated 

parameters and all were within 3 percent (0.01 order of 

magnitude) of the calibrated values. This supports the 

assumption of steady-state conditions for streamflow 

infiltration being represented by a long-term average and 

that large departures from the estimated average would not 

affect steady-state results for the estimation of hydraulic 

conductivity.

Head Distribution on Southwest Boundary

Little data are available to describe the hydrology of the 

aquifer near the downgradient boundary (figs. 4D and 8). Data 

on head differences with time are sparse, and data on head 

differences with depth are non-existent. The sensitivity of 

the model to head differences with depth along the southwest 

model boundary was tested by recalibrating the model with 

an increase (alternative model G) and a decrease (alternative 

model H) in head of 2.5 ft per 100 ft of depth, which is a 

vertical gradient of 0.025, similar to the vertical gradient 

(0.021–0.031) measured at the USGS 30 piezometer nest 

(tables 13 and 18). The estimated parameter values in the 

alternative models were nearly identical to the values in the 

calibrated model (table 14) with a small, 6 percent (0.02 order 

of magnitude), increase or decrease in the value of parameter 

HC3. All other parameters were within 1 percent (0.01 order 

of magnitude) of the calibrated values. No alternative model 

parameter values were outside of the confidence intervals 

for the base case parameters. The model calibration is only 

slightly sensitive to changes in the head with depth near the 

downgradient (southwest) boundary.
Model Calibration 77

Transient Calibration

Understanding the aquifer response to transient stresses 

is important because groundwater and contaminant movement 

through the aquifer may be substantially affected by these 

stresses. To investigate the aquifer response, the transient 

flow model was calibrated over a 16-year period of record 

(1980–95) that included a 5-year wet cycle (1982–86) 

followed by an 8-year dry cycle (1987–94) (fig. 10). 

Modeling groundwater flow during this period provided an 

opportunity to evaluate the relation between transient stresses 

and temporal changes in the altitude of the water table and 

groundwater flow directions. Modeling temporal changes in 

the altitude of the water table also allowed the specific yield 

of the hydrogeologic units present at the water table to be 

estimated. These values of specific yield can be used along 

with field measurements of porosity and other information 

to approximate the effective porosities of the hydrogeologic 

units, which is a necessary hydraulic parameter for simulating 

the velocities and travel times of groundwater flow and 

groundwater contaminants.

The three-dimensional, six-layer unconfined transient 

model was calibrated with nonlinear regression methods. 

The steady-state model provided the initial conditions for 

the transient model, and the hydrogeologic zones and model 

parameters are the same as for the steady-state model. The 

calibration observations included heads during the steady-state 

modeling period and head differences (Hill 1998, p. 33) during 

the transient modeling period. Qualitative and quantitative 

evaluation of the model results was performed through 

(1) statistical analyses of the estimated parameters, (2) visual 

comparison of the distribution of observed and simulated head 

differences and flow directions throughout the model area, 

and (3) statistical analyses of model fit and the distribution of 

weighted residuals for head differences.

Initial Conditions

Initial head conditions for the transient model were the 

1980 conditions simulated by the steady-state model. The 

presence of approximate steady-state aquifer conditions in 

1980 was supported by observed fluxes in 1980 that were 

nearly equal to average fluxes for the period 1950–80, a 

period that followed initial development of the aquifer for 

agriculture (Garabedian, 1992; Ackerman, 1995). The period 

after 1980 was characterized by some of the wettest and driest 

years on record (Pittman and others, 1988; Bartholomay and 

others, 1995, 1997, 2000) and provided a clear contrast with 

the period prior to 1980, in terms of hydraulic stresses and 

responses. The top of model layer 1 was increased 25 ft to 

accommodate water-table rise during transient simulations.

Model Parameters

Transient model parameters included specific yield (SY), 

specific storage (SS), HC, and VANI (table 8). The parameters 

SS and VANI had constant fixed values for the entire model 

domain. The HC parameter definition was the same as in 

the steady-state model. An SY parameter was defined for 

each hydrogeologic zone at the water table in model layer 1. 

Parameter-estimation model runs were attempted with (1) HC 

parameters specified and SY parameters estimated and (2) HC 

and SY parameters estimated.

For the model runs in which HC parameter values were 

specified, five SY parameters (SY1, SY2, SY3, SY11, and 

SY44) were estimated; all other model parameters (all HC 

parameters, VANI, SS, SY4, SY6, and SY22) were fixed 

(table 8). SY33 has no parameter because hydrogeologic zone 

33 is absent in model layer 1. The HC and VANI parameter 

values were fixed at the values estimated or specified for the 

steady-state model. The fixed value for parameter SS was set 

at 0.000015 ft-1. This value is the average of the geometric 

means of the minimum and maximum estimated SS values for 

fissured and jointed rock and dense sand (Domenico, 1972, 

table 5.1), materials that compose the bulk of the aquifer. 

Simulations with a range of values for the parameter SS 

indicated that the model was less sensitive (little change in 

model fit) for values corresponding to the range of fissured 

and jointed rock and very sensitive (decrease in model fit and 

parameter estimation would not converge) with larger values 

of SS in the range of dense sand (fig. 26). Fixed parameter 

values for SY were set at 0.05 for SY4 and SY6 and 0.15 

for SY22. These values reflect the assumption that the SY of 

basalts in hydrogeologic zones 4 and 6 is small and that the 

SY of hydrogeologic zone 22 is large because of the presence 

of abundant sediment in this zone.

Regression modeling with SY and HC parameters 

estimated (joint parameterization) was attempted but was 

unsuccessful. One five-parameter simulation (three HC and 

two SY parameters) with a lowered closure tolerance and 

reduced maximum parameter change slightly improved the 

simulation of differences, but with one parameter correlation 

of 0.98 and strongly degraded the simulation of head. In the 

joint parameterization regression models, the observations 

of head difference modified hydraulic conductivity values 

smoothing the water-table gradients and degrading the 

effect of sedimentary features on the head distribution. The 

observations were only sufficient to estimate one specific 

yield parameter corresponding to areas of sediment influence. 

The combination of head and head-difference observations 

supported too few model parameters in joint parameterization 

to match the overall spatial quality of simulated head from the 

steady-state HC parameters. Consequently, all the following 

calibrated transient model results were derived from the 

regression run in which only SY parameters were estimated.
78 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Model Results and Evaluation

Transient model results included estimated values for 

specific yield and the simulated hydraulic head and flux for 

each active cell in the model area. Methods for evaluating 

model results and the conceptualization and implementation 

of the model were similar to those described in the section 

Steady-State Calibration. 

Estimates of Specific Yield

Estimated values of SY parameters ranged from 0.028 to 

0.115 (table 15). In a manner similar to the steady-state model, 

confidence in the estimated parameter values was evaluated 

by (1) comparing field or laboratory values, (2) checking 

parameter uniqueness with parameter correlation coefficients, 

(3) comparing linear confidence intervals to expected ranges, 

and (4) identifying whether parameters were significantly 

influenced by a single observation using Cook’s D and 

DFBETAS influence statistics. Using these criteria, greater 

confidence is warranted for the estimates of parameters SY1, 

SY11, and SY44 than for the estimates of SY2 and SY3.

ID19-0164_GWflow_fig. 26

1.E-07 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02

Specific storage, in feet-1

Standard error of the regession

Range of specific storage

Standard error of the regression

Rock, sound

Rock, fissured, jointed

Dense

sandy

gravel

Dense

sand

Loose sand

Medium-hard clay

Stiff clay

Plastic clay

Calibrated 

model 

value

Model does not converge 

with values of specific 

storage greater than 

0.00006 ft-1

16.00

16.25

16.50

16.75

17.00

Figure 26. Ranges of values and sensitivity of the objective function to values of specific storage for 

model of transient groundwater flow, Idaho National Laboratory and vicinity, Idaho. Specific storage data 

from Domenico (1972, table 5.1).

Table 15. Estimates of specific yield, expected intervals, and 

95-percent confidence intervals for calibrated model of transient 

groundwater flow, Idaho National Laboratory and vicinity, Idaho.

[Specific yield is dimensionless. Abbreviation: SY, specific yield]

Hydraulic 

property 

parameter

Expected interval

Estimated 

value

95-percent 

confidence interval

Lower 

limit

Upper 

limit

Lower 

limit

Upper 

limit

Parameters corresponding to hydrogeologic zones in 

areas where the presence of sediment does not affect 

hydraulic property estimates

SY1 0.01 0.30 0.072 0.068 0.077

SY2 .01 .30 .115 .099 .133

SY3 .01 .30 .055 .039 .078

Parameters corresponding to hydrogeologic zones where the 

presence of sediment does affect hydraulic property estimates

SY11 0.01 0.30 0.072 0.066 0.077

SY44 .01 .30 .028 .023 .035
Model Calibration 79

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

SY1 SY11 SY2 SY3 SY44

Parameter name

Specific yield, ratio

Optimized value

Minimum observed

Lower 95-percent confidence interval

Upper 95-percent confidence interval

Figure 27. Estimated values of specific yield with 95-percent confidence intervals for model of transient 

groundwater flow, Idaho National Laboratory and vicinity, Idaho. Maximum expected values of specific yield are 

greater than 0.14.

All the estimated SY parameter values were within the 

range of expected values (fig. 27) for aquifers, 0.01 to 0.30 

(Freeze and Cherry, 1979, p. 61), and the range of values for 

porosity of basalt and other estimates of specific yield for 

basalt (table 3; Ackerman and others, 2006, p. 20-23). The 

values also were consistent with ranges of values of porosity 

for dense, vesicular, and fractured basalts in the Columbia 

River Plateau (Freeze and Cherry, 1979, table 4.1). The values 

for SY1 and SY2, 0.072 and 0.115 (table 15), respectively, are 

the reverse of expected relative values for these parameters 

based on an expectation that porosity and specific yield 

are related. Conceptually, hydrogeologic unit 2 consists 

of thicker, denser, basalt flows, fewer fractures, and fewer 

interflow zones than hydrogeologic unit 1. Based on these 

hydrogeologic features and on published values of porosity 

for dense and fractured basalt in the Columbia River Plateau 

(Freeze and Cherry, 1979, p. 162, table 4.1) the porosity, and 

consequently the SY, of the fractured basalt of hydrogeologic 

unit 1 may be expected to be larger than the porosity of the 

dense basalt of hydrogeologic unit 2. No data are available 

to support this expectation. The amount of the total porosity 

that drains will be related to interconnectedness and the 

capillary characteristics of water in the pore and fracture 

structure. Aquifer tests, often used to estimate specific yield, 

have not yielded much information on the storage properties 

of the aquifer. The availability and problems associated with 

large‐scale aquifer tests in the vicinity of the INL are described

in Ackerman (1991).

Parameter correlation coefficients for the transient model 

parameters were all less than 0.58. These small correlation 

coefficients are well below the critical value of 0.95, and 

indicate that all the parameters were estimated uniquely.
80 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

All the 95 percent linear confidence intervals of the SY 

parameters were within the ranges of expected values for 

these parameters (fig. 27). Confidence intervals for SY2 and 

SY3, however, were two to three times larger than confidence 

intervals for SY1, SY11, and SY44, but still cover relatively 

narrow ranges of values. These large confidence intervals 

generally are associated with SY parameters of hydrogeologic 

zones that contain the fewest observations (table 6) and have 

the smallest CSS (SY2, SY3, and SY44; fig. 28). The SY 

parameter values not estimated were most often those with 

lowest relative values of CSS (fig. 28) indicating that less 

information is provided by observations for defining those 

parameters and estimating parameter values. The smaller 

confidence intervals for SY1 and SY11 also may reflect their 

proximity to the Big Lost River (fig. 19A). Large changes in 

water-table altitudes occur near the Big Lost River in response 

to highly variable amounts of streamflow infiltration. These 

large changes in water-table altitude increase the sensitivity of 

simulated head differences in these areas. 

As with the steady-state model, the linear confidence 

intervals were calculated assuming independent and normally 

distributed errors and model linearity, and the accuracy of 

the confidence intervals decreases if these assumptions are 

not met. The independence and normality of the weighted 

residuals were evaluated using a normal probability plot of 

the ordered weighted residuals and the associated correlation 

coefficient, R2

N. On the normal probability graph, the 

weighted residuals nearly form a straight line (fig. 29), which 

indicates that the residuals deviate from being normally 

distributed. R2

N was 0.959, which was smaller than the 

critical value of 0.987 (at the 5 percent significance level), 

below which residuals are not likely independent or normally 

distributed. The linearity of the model was evaluated using 

the modified Beale’s measure. The calculated value of 0.078 

is less than the criteria of 0.44 for non-linearity, but greater 

than the criteria of 0.040 for effective linearity (table 16). The 

nearly normal distribution of the weighted residuals and the 

moderate nonlinearity of the model indicate that the calculated 

linear confidence intervals for the parameters may be fairly 

accurate.

The influence of specific transient head observations 

on the set of estimated parameter values and on individual 

parameter estimates was evaluated with Cook’s D and the 

DFBETAS statistic, respectively. Cook’s D values greater than 

the critical value of 0.00047 were computed for 684 transient 

head observations and DFBETAS values greater than the 

critical value of 0.022 were computed for 1,454 observations. 

All these observations had the potential to significantly 

influence parameter values.

The 10 largest Cook’s D values and 10 of the 11 largest 

DFBETAS values corresponded to the 5 observations at well 

USGS 8 between May and September of 1984, a period that 

includes the peak of the water-level rise in 1984 at this well. 

The Cook’s D and DFBETAS values also correspond to 

the five observations at well Site 2 between April 1993 and 

April 1995, a period that includes the lowest water levels at 

this well during the simulation period. Well USGS 8 is west 

of the INL, about 1 mi southwest of the Big Lost River where 

it enters the INL (fig. 1). The aquifer near the water table, 

model layer 1, in this location consists of hydrogeologic 

zone 2 (figs. 13 and 19A). Well Site 2 (fig. 1; fig. B1) is 

approximately 10 mi southwest of the southwest corner of 

the INL, and the aquifer near the water table in this location 

consists of hydrogeologic zone 3 (figs. 13 and 19A).

Two model recalibrations were done, the first without the 

five observations from well USGS 8 and the second without 

the observations from well Site 2. The first recalibration 

resulted in an increase in the 95 percent confidence intervals 

of all the estimated parameters and an increase in parameter 

value SY2 from 0.115 to 0.102 (table 17). The new estimated 

value for SY2 was inside the original confidence interval for 

this parameter (fig. 27). The second recalibration resulted 

in a small increase in the 95 percent confidence interval for 

SY3 and an increase in SY3 from 0.055 to 0.081 (table 17). 

The new estimated value for SY3 was outside the original 

confidence interval for this parameter (fig. 27), but within the 

range of expected values. All other new estimated parameter 

values were within the original 95 percent confidence intervals 

for the parameters. Parameters SY2 and SY3 are influenced by 

single observations more than are other estimated parameters, 

likely because hydrogeologic zones 2 and 3 have only 2 and 

7 wells, respectively, open only to model layer 1, whereas 

zones 1, 11, and 44 have 27, 36, and 22 wells, respectively, 

open only to model layer 1 (table 6). Although the 95 percent 

confidence intervals and influence statistics show that the 

estimate of SY2 is more uncertain than the estimates of 

parameters SY1, SY11, and SY44, the estimate of SY2 still is 

considered reasonably well constrained because its confidence 

interval spans a relatively small range of values.
Model Calibration 81

Figure 28. Composite scaled sensitivities for model of transient groundwater flow, Idaho National Laboratory and vicinity, 

Idaho.

Figure 29. Normal probability plot for model of transient 

groundwater flow, Idaho National Laboratory and vicinity, 

Idaho.

ID19-0164_GWflow_fig. 28

0.010

0.100

1.000

10.000

Normalized composite scaled sensitivity, dimensionless

SY1 SY2 SY3 SY11 SY44 SY4 SY6 SY22 SS

Parameter name

Estimated Fixed

-4

-3

-2

-1

0

1

2

4

3

Weighted residual, dimensionless

Standard normal statistic, dimensionless

-120 -80 -40 0 40 80 120

Table 16. Statistical measures related to parameter uncertainty 

and overall goodness of model fit for model of transient 

groundwater flow, Idaho National Laboratory and vicinity, Idaho.

[All statistics dimensionless. R2

N, correlation coefficient between ordered 

weighted residuals and normal order statistics]

Statistic

Parameter structure

Big Lost Trough sediment

Sum of squared weighted residuals 2,226,390

Average weighted residual 1 .80

Parameter correlation coefficients 2 None

Standard error of the regression 16.32

R2

N .959

Modified Beale's measure .078

1

 Positive average weighted residual indicates that, on average, weighted 

observed values were greater than weighted simulated values.

2

 Parameter correlation coefficients greater than 0.90.
82 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Distribution of Head and Inferred Flow Directions

Comparison of simulated and observed heads and flow 

directions were used to evaluate how well the transient 

model represented recharge and flow in the ESRP aquifer. 

A qualitative evaluation of the model was made through 

comparison of simulated and observed (1) changes in water 

levels and horizontal flow directions and (2) changes in 

vertical gradients and flow directions. Quantitative evaluation 

of the model was done by analyzing the model fit and 

the distribution of weighted residuals for head-difference 

observations. 

As in the steady-state model, simulated equivalents 

to observed heads were calculated by MODFLOW-2000 

and used spatial interpolation in the horizontal plane and 

calculation of multilayer heads for wells open to multiple 

model layers. In the transient model, simulated equivalents to 

observed heads also were calculated by temporal interpolation. 

Simulated head differences were calculated from these values. 

The quality of the transient model can be demonstrated 

by its ability to simulate the head difference with time and 

the differing magnitude and timing of water-level changes in 

response to changes in locations of infiltration. The quality of 

the model also is demonstrated by comparing the simulated 

changes in vertical gradients and the distribution of residuals 

in time and space. Simulation of transient conditions gave an 

accurate representation of observed changes in the flow system 

resulting from episodic infiltration from the Big Lost River. 

The simulation facilitated understanding and visualization of 

the relative effects on heads and flows caused by (1) extended 

periods of flow and drought related to climate variability; 

(2) differences in infiltration between channels, playas, and 

spreading areas; and (3) changes in distribution of infiltration 

resulting from regulating diversion to the spreading areas. 

Simulation of transient conditions did not reproduce 

observed annual fluctuations of water levels over the northeast 

one-third of the model area and produced limited annual 

fluctuations of water levels in the northeast corner of the 

model area. These regular observed annual fluctuations, 

believed to originate in response to irrigation in the northeast 

corner of the model area and irrigation to the north of the 

model area, are superimposed on the other responses, which 

were demonstrated by the model. Overall, the quality of 

the simulation of water-level change is good, especially in 

areas with abundant head data that coincides with the area of 

greatest interest near observed contamination of the aquifer in 

the southwestern part of the INL.

Changes in Water Levels and Flow Directions

As discussed in the previous section on steady-state 

calibration, observed water-level altitudes were not matched 

exactly. A comparison of observed and simulated heads 

(fig. 30) shows that general geometry and altitude of the water 

table is well simulated in the model. At any particular well 

location, however, simulated and observed heads will differ. 

Rather than compare just simulated and observed water-levels 

for transient model analysis, hydrographs (fig. 31) also show 

residuals of head differences (differences between simulated 

head difference and observed head difference).

Table 17. Summary of observations and corresponding parameters with highest 

values of influence measures for model of transient groundwater flow, Idaho National 

Laboratory and vicinity, Idaho.

[Critical values for Cook’s D and DFBETAS were 0.00047 and 0.022, respectively. Recalibrated 

parameter values result from omitting five observations for recalibration. Parameter: Associated with 

DFBETAS statistic. Abbreviations: SY, specific yield]

Observations

Cook's D Parameter DFBETAS

Specific yield

Base case 

model

Recalibrated 

Well model Date

USGS 8 July 1984 0.0374 SY2 -0.431 0.115 0.102

USGS 8 June 1984 .0290 -.380

USGS 8 August 1984 .0277 -.372

USGS 8 September 1984 .0209 -.322

USGS 8 May 1984 .0205 -.319

Site 2 April 1995 .0290 SY3 -.372 .055 .081

Site 2 September 1994 .0270 -.359

Site 2 September 1995 .0253 -.347

Site 2 September 1993 .0217 -.322

Site 2 March 1994 .0207 -.314
Model Calibration 83

ID19-164_GWflow_fig. 30A

A.

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Big Lost River

Birch

Creek

Mud Lake

Camas Creek

MFC

INTEC

RWMC

TAN

RTC

CFA

NRF

Big Lost River

Sinks and 

Playas

Howe

Mud

Lake Terreton

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

Atomic

City

East

Butte

Middle

Butte

Big Southern

Butte

4560

4540

4580

4450

4520

4480

4500

4460

4460

4470

4460

4470

4600

4400

4420

4580

4600

4600

4560

113°00' 112°45' 112°30' 112°15'

43°

30'

43°

45'

44°

00'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

0 10 Miles

0 10 Kilometers

Model area boundary

EXPLANATION

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

4500 Simulated water-table contour—Stress period 22,

December 1987. Interval 10 feet. Datum is National 

Geodetic Vertical Datum of 1927.

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

1:100,000. Universal Transverse Mercator projection, Zone 12N; 

North American Datum of 1927.

Figure 30. Comparison of (A) simulated water table, December 1987 and (B) observed and simulated water table, April 

1995, Idaho National Laboratory and vicinity, Idaho.
84 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-164_GWflow_fig. 30B

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Big Lost River

Birch

Creek

Mud Lake

Camas Creek

MFC

INTEC

RWMC

TAN

RTC

CFA

NRF

Howe

Mud

Lake Terreton

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

Atomic

City

East

Butte

Middle

Butte

Big Southern

Butte

4540

4560

4520

4440

4480

4500

4460

4460

4450

4430

4580 4600

4420

4410

4400

4600

4600

4580

4580

4560

4500

4600

4580

4560

4560

4400

4440

4460

4480

113°00' 112°45' 112°30' 112°15'

43°

30'

43°

45'

44°

00'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

0 10 Miles

0 10 Kilometers

Model area boundary

EXPLANATION

4500

4500

Water-table contour—Shows altitude of water table. March– 

May, 1995. Interval 10 feet. Dashed where approximately 

located. From Bartholomay and others (1997, figure 9). Datum is 

National Geodetic Vertical Datum of 1927 (NGVD27). 

Simulated water-table contour—Stress period 44, April 1995. 

Interval 10 feet. Datum is NGVD27.

Well at which water-level was measured. Open circle denotes 

water-level measurement for February or June 1995

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

B.

Big Lost River

Sinks and 

Playas

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

1:100,000. Universal Transverse Mercator projection, Zone 

12N; North American Datum of 1927.

Figure 30.—Continued.
Model Calibration 85

Figure 31. Observed and simulated hydraulic head, head-difference observation times, and residuals of 

head difference for wells (A) MTR TEST, (B) USGS 87, (C) USGS 25, and (D) USGS 18 at various locations in 

the transient model of groundwater flow, Idaho National Laboratory, Idaho. Residuals of head difference 

are differences between simulated head difference and observed head difference.

ID19-0164_GWflow_fig. 31AB

A. Well MTR TEST

Altitude of water level, in feet

Residual of head difference, in feet

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995

Year

Altitude of water level, in feet

Residual of head difference, in feet

4,425

4,430

4,435

4,440

4,445

4,450

-10

-5

0

5

10

15

B. Well USGS 87

Observed heads

Head-difference observation times

Simulated heads

Residuals of head difference

4,450

4,455

4,460

4,465

4,470

4,475

-10

-5

0

5

10

15

Observed heads

Head-difference observation times

Simulated heads

Residuals of head difference
86 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 31CD Altitude of water level, in feet

Residual of head difference, in feet 

4,570

4,575

4,580

4,585

4,590

4,595

-10

-5

0

5

10

15

C. Well USGS 25

Observed heads

Head-difference observation times

Simulated heads

Residuals of head difference

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995

Year

Altitude of water level, in feet

Residual of head difference, in feet

4,525

4,530

4,535

4,540

4,545

4,550

-10

-5

0

5

10

15

D. WELL USGS 18

Observed heads

Head-difference observation times

Simulated heads

Residuals of head difference

Figure 31.—Continued.
Model Calibration 87

The hydrograph of well MTR TEST (figs. 1 and 31A) is 

the most complete record representative of water levels near a 

major area of aqueous waste disposal. The hydrograph shows 

two peaks, one peak in 1985, and a broad peak from 1986 to 

1987. The response in this area corresponds to the pattern of 

initially higher infiltration and the accumulating effects of 

infiltration from the channel of Big Lost River between the 

INL diversion and the Big Lost River Sinks and in the sinks 

and playas from the beginning of the simulation to 1986 

(table C1). Figure 31A demonstrates model fit, the ability of 

the model to simulate the head difference with time, and the 

differing magnitude and timing of water-level changes in 

response to changes in locations of infiltration.

The hydrograph for well USGS 87 (figs. 1 and 31B), 

just north and east of the spreading areas (fig. 1) shows that 

simulated heads peaking in the late summer 1984 match the 

timing of major diversion of streamflow to the spreading 

areas in 1984 (fig. 10; table C1). Overall, the simulated head 

differences provide a good match to the observed changes. 

Overestimates and underestimates of the magnitude of waterlevel change in this area of the model probably are related 

to uncertainty in the distribution of infiltration of ungaged 

flow below the outlet of spreading area A to spreading area B 

(stream gage 503, fig. B1).

The hydrograph of well USGS 18 (figs. 1 and 31D), 

representative of water-table conditions at a location 

upgradient of the major area of aqueous waste disposal and 

just east of the terminal playas of the Big Lost River, shows 

the simulation of two peaks as a result of infiltration from 

the Big Lost River Sinks and Playas. Differences in the 

magnitude of some of the observed and simulated peaks may 

be caused by errors in the estimation of the relative amounts 

of infiltration in the sinks and the separate playas (fig. 10; 

table C1) in an area with few discharge records. The amount 

of data from wells representing only model layer 1 (watertable conditions) and the coarse definition of the influence 

of sediment on hydrologic parameters in the model area also 

limits the ability of the model to estimate the local variations 

in specific yield, which in turn affect the simulation of changes 

in water level in individual wells. 

In well USGS 18 (figs. 1 and 31D) and others to the 

north and east such as USGS 25 (figs. 1 and 31C) water 

levels reflect a slightly more subdued cycle of changes in 

water-levels corresponding to the wet period and following 

dry period simulated in the model compared to changes 

measured in wells near the spreading areas (fig. 31B). 

The effects of the episodic infiltration, likely focused in 

the sinks and playas (fig. 10; table C1) of the Big Lost 

River, diminish with distance from the Big Lost River and 

become indistinguishable from a basin-wide change in 

streamflow infiltration that originates from precipitation in 

the mountainous tributary basins (Lindholm, 1996, p. 41). 

Although the simulated response of these wells demonstrates 

the ability of the model to simulate multi-year processes, they 

do not reproduce regular annual fluctuations. In these wells 

and others to the north and east, the water levels reflect an 

annual cycle likely due to the seasonal effects of irrigation in 

the northeast corner of the model area and areas north and east 

of the model. The influence of irrigation is likely complex due 

to withdrawals from wells and infiltration of excess applied 

irrigation from surface water and groundwater sources. 

Wells in and adjacent to the northeast corner of 

the model area have annual water-level fluctuations of 

approximately 4–7 ft. Wells in the northeast area of the INL, 

such as wells USGS 27, USGS 25, and USGS 18 (figs. 1, 

17, 31C, 31D), have annual fluctuations of between 2 and 

4 ft. With increasing distance from the irrigated area in the 

model, annual fluctuations of water levels diminish. Annual 

fluctuations are about 2.5 ft in the east-central area of the 

INL (well USGS 21), 2 ft (well USGS 6) in the central INL, 

and less than 2 ft (well USGS 2) southwest of MFC (fig. 1). 

Regular annual fluctuations of water levels are less than 0.5 ft 

to indistinguishable south and west of a line from NRF to the 

southeast corner of the INL. For example, the wells MTR 

TEST and USGS 87 (fig. 31A, B) are west of that line in the 

area where most waste was disposed and nearly all medium 

to long half-life contaminants were detected. A fine detail 

comparison of the responses for wells USGS 27 and MTR 

TEST is shown in figure 17.

Changes in Vertical Gradients and Flow Directions

Throughout most of the model area, the simulated 

directions of vertical gradients between model layers rarely 

changed with time. Exceptions are near INTEC and along the 

Big Lost River from the INL diversion to the sinks, where 

simulated directions of vertical gradient between model layers 

1 and 2 changed to downward during the extended wet period 

1983–87, and then reverted to upward during the following 

dry period. These changes in directions were caused by 

changes in pumpage and disposal at INTEC and the influence 

of infiltration from the Big Lost River channel (table 18). 

Changes in simulated vertical gradients in the immediate 

vicinity of INTEC are influenced by (1) the simulated 

injection of waste into model layers 1 and 2 from the 

beginning of the simulation through 1984, (2) recharge from 

infiltration of industrial wastewater, (3) withdrawals from 

production wells, and (4) the relatively constant infiltration of 

streamflow in the channel from the INL diversion to the Big 

Lost River Sinks from the beginning of simulation to early 

1987. The level of discretization used in the calibrated model 

is sufficient to allow simulated injection of waste, infiltration 

of wastewater, and industrial withdrawals in separate cells 

and to avoid summing of simulated inflows and outflows that 

result in a smaller net stress within a single cell. A larger cell 

size may not appreciably affect the calibration of the flow 

model as shown in a sensitivity analysis, use of the model for 

advective transport analysis or advective/dispersive transport 

model calibration may benefit from the current cell size.
88 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table 18. Observed and simulated transient directions and gradients of groundwater flow in open boreholes, 

piezometer nests, and packer-isolated intervals of wells, Idaho National Laboratory, Idaho.

[Methods, qualifications, and references for observed data in table 13. Gradient: Values are dimensionless; data for flow between layers 1 and 

2 except as noted. Simulated values: December 1980, steady-state, stress period 1; August 1982, stress period 9; April 1995, stress period 44. 

Abbreviation: –, no information]

Date Well 

name

Observed

Simulated values

December 1980 August 1982 December 1995

Direction of 

flow Gradient Direction of flow Gradient Direction of flow Gradient Direction of flow Gradient

Northeast Idaho National Laboratory and southeast of Test Area North

1966 USGS 4 Down 0.001 to 0.007 Up 0.003 Up 0.002 Up 0.002

1980–95 USGS 30 Up 10.018 to 0.032 Down .0002 Down .022 Down .023

1980–95 USGS 30 Up 10.021 to 0.032 Up 2 .044 Up 2 .044 Up 2 .043

1963 USGS 31 Up – Down .007 Down .004 Down .011

 Idaho Nuclear Technology and Engineering Center

1965 USGS 42 Up – Up 0.001 Down 0.006 Up 0.006

1965 USGS 43 Static – Up .001 Down .010 Up .010

1991 USGS 44 Up – Up .001 Down .008 Up .008

1991 USGS 45 Up – Up .002 Down .007 Up .007

1991 USGS 46 Up 3 – Down .001 Down .007 Up .007

1963 USGS 47 Up – Down .003 Down .007 Up .007

1965 USGS 48 Static 4 – Up .005 Down .002 Up .003

1965 USGS 48 Down 4 – Up 5 .008 Up 5 .008 Up 5 .011

1965 USGS 49 Down 4 – Up .006 Up .000 Up .004

1965 USGS 51 Up – Up .011 Up .009 Up .002

1965 USGS 52 Up 6 – Up .004 Down .000 Up .010

1965 USGS 59 Up 6 – Up .012 Up .009 Up .003

North of Naval Reactors Facility

1964 Site 17 Down – Down 0.013 Down 0.006 Down 0.010

Reactor Technology Complex

1964 MTR test Down 7 – Up 0.006 Up 0.006 Up 0.012

1

 Range of gradients observed from 1980 to 1995. Water-level data are from http://nwis.waterdata.usgs.gov/id/nwis/gwlevels.

2

 Simulated flow between model layers 2 and 4.

3

 Observed gradient is down when nearby production well is pumping.

4

 Observed direction may be influenced by nearby injection well.

5

 Simulated flow between model layers 2 and 3. 

6

 Observed direction may be influenced by nearby injection or production wells.

7

 Observed direction may be influenced by nearby infiltration pond.
Model Calibration 89

Analysis of Residuals

As discussed in the previous section on steady-state 

calibration, weighted residuals that are not randomly 

distributed can be an indication of model error. Although most 

discussion in this section describes weighted residuals, which 

are by definition dimensionless, a more intuitive measure of 

model fit is available that can be expressed in the original 

dimensions of measurement (feet). Because all observations 

of difference in head have the same weight, the fitted standard 

deviation can be calculated for the transient model. The fitted 

standard deviation for differences in heads (2.10 ft) is small 

compared to the range of differences in heads (36 ft). This 

indicates that errors are only a small part of the overall model 

response.

Weighted residuals of differences in head were plotted 

against weighted simulated equivalents (fig. 32) to evaluate 

if the weighted residuals were randomly distributed. The 

mean weighted residual of differences in head was near zero 

(0.82 for 8,171 observations). The weighted residuals within 

±2s were randomly distributed about zero for all weighted 

simulated values. For weighted residuals greater than the 

absolute value of 2s, weighted simulated values between -50 

and 0 have a negative bias, and values between about 10 and 

60 have a positive bias.

Residuals of head differences were plotted against 

time (fig. 33) to evaluate bias with time. The residuals were 

generally close to zero, but for some wells, residuals varied 

according to annual cycles or reflected apparent systematic 

model error due to the resolution of inflow from infiltration 

of streamflow in playas, sinks, and spreading areas. The 

residuals with absolute values greater than 2s, as mentioned 

previously, often correspond to high or low points in the 

year on the hydrographs with strong annual fluctuations. The 

trend in residuals with time, if any, is difficult to determine 

using the scatter plot of residuals in figure 33. The trends in 

observed head difference and residuals are better summarized 

by annual summaries (fig. 34). The slight variation in average 

residuals (fig. 34B) from year to year does not follow the large 

head differences from year to year (fig. 34A) in magnitude or 

timing indicating that model error was generally independent 

of the large simulated changes in streamflow that caused large 

simulated head differences. The number of observations per 

year averaged 558 and ranged from 356 in 1986 to 715 in 

1984.

The areal distribution of weighted residuals (fig. 35A) 

shows the location where observed head difference for 

seven wells is underestimated (positive weighted residual) 

in the west-central area of the INL (near the NRF) for a 

time corresponding to the end of the extended wet period. 

This area generally is where the distribution of infiltration 

from streamflow is not well documented, the observed head 

difference is largest, and few wells are completed in model 

layer 1 only. The highest weighted residuals, for well USGS 

98 (77.4) and nearby wells (44.4), may be caused by local 

sediment interbeds acting as confining beds within the first 

model layer at and near the water level. The presence of 

confining beds at or just below the water table has been noted 

in well completion documents in this area. A temporary 

change in the configuration of well USGS 98 near NRF in 

January 1994 resulted in a several foot drop in water level and 

a downhole video log showed strong downward flow between 

perforations above and below a 29-ft thick sediment bed. Near 

the end of the simulated dry cycle, weighted residuals were 

uniformly smaller and showed little areal bias (fig. 35B).

Hydrographs for several wells (fig. 31) further illustrate 

the nature and location of higher residuals and probable causes 

for the errors. Residuals for well MTR TEST (fig. 31A) are 

only slightly positive for most of the simulation indicating 

possible minor errors in storage or distribution of infiltration 

near this well in the area of greatest interest. This simulated 

response is typical in areas where cyclical annual variations 

of water levels are absent and infiltration of streamflow is 

relatively well known.

Residuals for well USGS 87 (fig. 31B) are positive 

early in the simulation and then negative later, perhaps 

in response to small errors in the steady-state and initial 

transient values for infiltration of Big Lost River flow to 

the spreading areas. Weighted residuals for well USGS 18 

(fig. 31D) are generally positive indicating head differences 

are underestimated, possibly caused by local variations in the 

distribution of hydraulic conductivity or specific yield that 

is not represented in the model. The area near well USGS 

18 is more abundant with sediment. The weighted residuals 

show an annual fluctuation indicating that a seasonal head 

difference is not simulated. Weighted residuals at well USGS 

25 (fig. 31C) show the head difference with time and indicates 

an underestimate of head difference and small difference in 

timing.

Analyses of Alternative Model Conceptualizations

The calibrated transient model was evaluated by 

examining the response of the model to alternative 

conceptualizations and quantities of inflow. In the analyses 

reported below, the effects of the alternative representations 

primarily are quantified in relation to the base case values of 

specific yield (SY) parameters. Results of simulations with 

alternative model conceptualizations or implementations 

are compared to the calibrated model simulation results 

to evaluate the selection of specific storage, uncertainty in 

boundary conditions, or possible shortcomings in the ability of 

the model to simulate some observed response. 
90 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 32

Standard error of the regression, dimensionless

Weighted residual of head difference, dimensionless

1s

-1s

-2s

2s

3s

4s

-3s

-4s

Weighted simulated head difference, dimensionless

-100

-80

-60

-40

-20

0

20

40

60

80

100

-90 -60 -30 0 30 60 90 120 150 180

EXPLANATION

Weighted residual of head difference—in terms of s, 

standard error of the regression

Figure 32. Distribution of weighted residuals of head difference for model of transient groundwater flow, 

Idaho National Laboratory and vicinity, Idaho.
Model Calibration 91

ID19-0164_GWflow_fig. 33

-15

-12

-9

-6

-3

0

3

6

9

12

15

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995

Year

Residual of head difference, in feet

Standard error of the regression, dimensionless

1s

-1s

-2s

2s

3s

4s

-3s

-4s

EXPLANATION

Residual of head difference—in terms of s, standard 

error of the regression

Note: Positive residual indicates that the observed value is 

greater than the simulated value.

Figure 33. Distribution of weighted residuals of head difference over time for model of transient groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.
92 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 34ab

-6

-8

-10

-4

-2

0

2

4

6

8

10

-6

-8

-10

-4

-2

0

2

4

6

8

10

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995

Year

EXPLANATION

Annual average head-difference observation—whisker 

length 1 standard deviation of the observations.

Annual average residual of head difference whisker length 

1 standard deviation of the residuals.

Average head-difference observation—whisker length 

1 standard deviation of the observations for December 

1987 or 1993.

Average residual of head difference—whisker 

length 1 standard deviation of the residuals for end of 

stress period 22 or 43, December 1987 or 1993.

B.

Head-difference observation, in feet Residual of head differences, in feet

A.

Figure 34. Distribution of annual and select monthly (A) head-difference observations and (B) residuals of 

head differences over time for model of transient groundwater flow, Idaho National Laboratory and vicinity, 

Idaho.
Model Calibration 93

ID19-0164_GWflow_fig. 35A

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

PIONEER MOUNTAINS

Atomic

City

Howe

Arco

Mud

Lake Terreton

Big Lost River

Sinks and 

Playas

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.

-2s to -1s

-1s to 0

0 to 1s

1s to 2s

Greater than 2s

Weighted residual of head difference—in terms of s, standard 

error of the regression

Note: Positive residual indicates that the weighted observed 

value is greater than the weighted simulated value.

A.

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Material and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Site facilities

Model area boundary

Idaho National Laboratory boundary

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

EXPLANATION

Mud Lake

WELL USGS 98

Figure 35. Distribution of weighted residuals of head difference for the end of (A) December 1987, stress period 22, and 

(B) December 1993, stress period 43, for model of transient groundwater flow, Idaho National Laboratory and vicinity, 

Idaho.
94 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 35B

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

PIONEER MOUNTAINS

Atomic

City

Howe

Arco

Mud

Lake Terreton

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Mud Lake

EXPLANATION

-2s to -1s

-1s to 0

0 to 1s

1s to 2s

Weighted residual of head difference—in terms of s, standard 

error of the regression

Note: Positive residual indicates that the weighted observed 

value is greater than the weighted simulated value.

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Material and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

Site facilities

Model area boundary

Idaho National Laboratory boundary

Big Lost River

Sinks and 

Playas

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.

B.

Figure 35.—Continued.
Model Calibration 95

Early in the calibration process, two analyses were 

used to check numerical considerations for the implemented 

transient simulation. The calibrated model was reconfigured 

to allow three time steps per stress period with a time 

step multiplier of 1.2. The alternative model had similar 

estimated values of parameters and no improvement in the 

sum of squared weighted residuals and standard error of the 

regression when compared to the calibrated model. The results 

imply that if future use of the model would benefit from a 

change in time discretization by use of additional time steps, 

the change could be made without recalibration.

Another analysis was made to re-evaluate the areal 

discretization of the model. Although initial modeling was 

done at a 0.5 mi grid spacing, final modeling has been done 

at a 0.25 mi spacing. Results from initial model runs were 

not directly comparable due to coincident changes in sets of 

calibration observations, grid spacing, and stress period length. 

The calibrated model with 0.25 mi spacing was subsequently 

reconfigured to 0.5 mi spacing and recalibrated. The 

alternative model had similar estimated values of parameters 

and slight increases in the sum of squared weighted residuals 

and standard error of the regression. A slight decrease in 

average weighted residual was estimated when compared to 

the calibrated model. The configuration of the model is not 

strongly sensitive to doubling the cell spacing. The results 

imply that the model could be used with a variable spacing 

that is less fine in areas remote from simulated contaminant 

travel to improve run-time efficiency for transport models.

Seasonal Variation of Northeast Boundary Flux

One possible reason the calibrated model did not simulate 

the annual component of water-level change is that underflow 

across the northeast boundary varies seasonally. Flux could 

vary seasonally following the general trend of annual cycles 

of water levels in wells, which probably respond to seasonal 

irrigation pumpage upgradient of the northeast boundary. 

The transient model was modified from the calibrated 

model implementation of flux simulating constant inflow 

across the northeast model boundary to an alternative model 

simulating seasonal variation in flux. Total flux remained 

constant from year to year at the same rate as the calibrated 

model, but was reduced to 60 percent of annual average during 

the simulated summer irrigation-pumping season for model 

layers 1 and 2 and 70 percent for layer 3. For the remainder of 

the year, flux increased to 160 percent of annual average flux 

for model layers 1 and 2 and 130 percent of annual average 

flux for layer 3. Flux into the model area across the boundary 

decreased 150 ft3/s during the simulated summer irrigationpumping season and increased 75 ft3/s for the remainder of the 

year compared to the annual average. 

The simulated values of head in the aquifer showed 

additional annual drawdown and recovery of as much as 17 ft 

adjacent to the northeast boundary. The effect of seasonal 

variation in flux dissipated quickly away from the boundary 

with additional annual drawdown and recovery of about 2 and 

1 ft within 3 and 6 mi of the boundary. 

Estimated parameter values for the simulation were 

close to those of the calibrated model except for SY44, 

which was 5 percent different, within 0.001 of the minimum 

of the confidence intervals of the calibrated model, and 

within the range of the confidence interval for the base case 

model (fig. 27; table 15). As an additional check, the model 

incorporating seasonal changes in northeast boundary flux 

was recalibrated with three time steps per stress period. 

The model with multiple time steps had similar estimated 

values of parameters to the alternative model and only a 

slight improvement in the sum of squared weighted residuals 

and standard error of the regression when compared to the 

alternative model. Perhaps further research and consideration 

of concepts of storativity for the layered basalts and better 

aquifer test procedures are needed to understand this problem 

and, if necessary, modify conceptual and numerical models of 

the aquifer. In summary, simulating seasonal changes in flux 

across the northeast boundary does not improve the calibration 

of the model nor substantially improve the simulation of 

annual fluctuations of head throughout the northeast quarter of 

the model area.

Evaporation of Big Lost River Streamflow Infiltration

The decision to include estimates of evaporation for 

transient model calibration was based on the possibility an 

overestimate of infiltration in sinks, playas, and spreading 

areas causing a bias in estimated values of specific yield that 

were not seen for hydraulic conductivity in the steady-state 

model. Because head differences are largest near the Big 

Lost River, the locus of changes in storage, the sensitivity of 

the transient model estimates of specific yield to streamflow 

infiltration might be greater than the sensitivity indicated for 

estimates of hydraulic conductivity in the steady-state model. 

Although the streamflow infiltration is relatively well known 

for most river reaches, neglecting small overestimates of 

infiltration that are a result of evaporation losses may bias 

estimates of specific yield. 

The size of the possible bias was evaluated by analyzing 

model recalibration without reducing streamflow infiltration 

by estimates of evaporation. The model recalibration was only 

slightly sensitive to the increase in estimated infiltration from 

neglecting evaporation losses. The bias generally resulted 

in estimated parameter values well within the range of the 

confidence intervals of the calibrated model except those of 

SY11 and SY2, which were 2 and 4 percent different and 

within 0.001 and 0.004, respectively, of the maximums of 

the confidence intervals for the calibrated model (fig. 27; 

table 15). Evaporation of streamflow in channels, sinks, 

playas, and spreading areas, as implimented for transient flow 

modeling, is an addition to the conceptual model.
96 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Analysis of Advective Flow and 

Transport

Particle-tracking simulations were performed to evaluate 

(1) how simulated groundwater flow paths and travel times 

differ between the steady-state and transient flow models, 

(2) the effects of wet- and dry-climate cycles on groundwater 

flow paths and travel times, (3) the effects of streamflow 

infiltration on advective transport, and (4) how well model 

predictions of the source and travel times of groundwater 

flow compare to estimates based on other indicators such as 

water chemistry, contaminant chemistry, and environmental 

tracers. These simulations did not include the effects of natural 

dispersive processes attributable to small-scale heterogeneity 

within individual hydrogeologic zones, lateral dispersion of 

pond infiltration through the unsaturated zone, and molecular 

and thermal diffusion.

Particle-tracking computations were made using 

MODPATH (Pollock, 1994), a post-processing program 

for MODFLOW-2000. MODPATH computes particle 

paths using a semi-analytical expression of the flow path 

of a particle within each cell and tracks the movement of 

the particle from one cell to the next until the particle is 

terminated at a boundary, an internal sink or source, or some 

other user‐defined criterion (Pollock, 1994, p. 1-1). Particle

movement was plotted to produce maps of 3-D flow paths in 

two dimensions. 

The spatial and temporal distribution of particle releases, 

and the duration of the particle-tracking simulations, varied 

depending on the purpose of the particle-tracking simulation. 

The number of particles released, location of cells where 

particles were released, distribution of the particles throughout 

cells, time(s) of particle release, and length of time that 

particle movement was simulated are presented at the 

beginning of each section where particle-tracking results are 

discussed.

Effective porosity values used in these simulations 

(table 19) are not calibrated and were estimated from largescale model-derived values of specific yield (table 15), 

small‐scale measurements of bulk or total porosities on

individual core samples (table 3), and literature derived 

estimates of porosity for similar rock types (Freeze and 

Cherry, 1979, p. 158).

Approximations in the particle-tracking computer code 

include how weak sink cells are treated. Weak sink cells are 

cells that contain sinks that do not discharge at a rate large 

enough to consume all the water entering the cell (Pollock, 

1994, p. 2-17). Because there is no way to know whether 

particles entering a weak sink cell discharge to the sink or 

pass through the cell, an approximation of particle behavior 

in the cell is necessary. For the particle-tracking simulations 

presented here, particles were instructed to terminate upon 

entering cells in which discharge to sinks is larger than 0.5 of 

the total inflow to the cells.

Comparison of Steady-State and Transient Flow

Particle tracking, simulated with the steady-state and 

transient flow models, was used to evaluate the influence 

of transient stresses on groundwater flow directions and 

average linear velocities. Transient stresses evaluated 

included (1) groundwater withdrawals from irrigation wells 

and infiltration from irrigation return flows; (2) streamflow 

infiltration from the Big Lost River channel, sinks, playas, and 

spreading areas; and (3) industrial groundwater withdrawals 

and wastewater return flows at the RTC and the INTEC.

Water-level rises throughout the model area were 

observed and simulated during the early- to mid-1980s, with 

the largest rises centered near the sinks and spreading areas 

(figs. 12 and 36). Observed heads, simulated heads, and 

residuals of head difference for wells USGS 9 and USGS 

87 (fig. 37) near the spreading areas (fig. 1) indicate that the 

transient flow model overestimated the maximum water-level 

rise during the wet cycle by about 10 ft at USGS 9 and by 

about 6 ft at USGS 87. Similarly, a contour map of water‐level

rises from July 1981 to July 1985 (fig. 12) indicates that 

the simulated water-table rise beneath the sinks also may 

be overestimated (fig. 36). Consequently, the influence of 

streamflow infiltration at the spreading areas and sinks on 

particle directions and velocities may be overestimated in the 

transient particle-tracking simulations. 

Table 19. Estimated effective porosity for groundwater model 

hydrogeologic zones, Idaho National Laboratory and vicinity, 

Idaho.

Hydrogeologic zone Estimated effective porosity

1 0.07

2 .14

3 .03

4 .05

11 .07

22 .15

33 .05

44 .03

6 .05
Analysis of Advective Flow and Transport 97

ID19-0164_GWflow_fig. 36

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Mud Lake

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC

CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

2

2

2

2

8

6

4

4

6

8

12

10

14

2

16

14

20

34

10

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Model area boundary

EXPLANATION

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

2 Simulated water-table rise, 1981–84, interval 2 feet

 Hydrogeologic zones, model layer 1

1—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally less than 11 percent

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally less than 11 percent

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

4—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

11—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally more than 11 percent

22—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

44—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

6—Silicic rocks, including rhyolite domes and andesite

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.

Figure 36. Simulated water-table rise from January 1981 through December 1984, Idaho National Laboratory and 

vicinity, Idaho.
98 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 37 Altitude of water level, in feet

Head-difference residual, in feet

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995

Year

Altitude of water level, in feet

Head-difference residual, in feet

4,425

4,420

4,430

4,435

4,440

4,445

4,450

4,455

-10

-5

0

5

10

15

20

4,425

4,430

4,435

4,440

4,445

4,450

-10

-5

0

5

10

15

-15

Well USGS 87

Observed heads

Head-difference observation times

Simulated heads

Residuals of head difference

Well USGS 9

Figure 37. Observed and simulated hydraulic head, head-difference observation times, and residuals of head 

difference for wells USGS 9 and USGS 87 from 1981 through 1995, Idaho National Laboratory, Idaho. Residuals of 

head difference are differences between simulated head difference and observed head difference.
Analysis of Advective Flow and Transport 99

Analysis of Steady-State and 

Transient Flow Paths

To evaluate how transient recharge influences 

groundwater flow, particles were released from identical 

locations in the steady-state and transient flow models and 

their paths were simulated for 10 years with the steady-state 

flow model and for 10 years, from 1983 through 1992, with 

the transient flow model. The transient simulation period 

included the last 4 years of an extreme wet-climate cycle 

(1983 through 1986) that also included the two largest 

recorded annual mean discharges for the Big Lost River onto 

the INL (1983 and 1984), and the first 6 years of an extreme 

dry-climate cycle (1987 through 1992) (fig. 10).

The particles, labeled A through O (fig. 38), were released 

in the steady-state and transient flow models at the center of 

15 cells in model layer 1. The release points were (1) restricted 

to model layer 1 because infiltration from the Big Lost River, 

which is by far the largest transient stress, was applied to 

this model layer and (2) selected to provide a distribution of 

particle paths throughout the model area, with an emphasis on 

release points near transient stresses. 

The A, B, and C particles originated near the northeast 

boundary of the model area within or near irrigated areas 

(figs. 18 and 38). The D, E, and F particles originated near 

the Big Lost River Playas and Sinks. The G, H, I, J, and K 

particles originated near the Big Lost River channel. The L 

and M particles originated east and northeast of the Big Lost 

River spreading areas, respectively. The N particles originated 

southwest of the RTC and the O particles originated south of 

the INTEC.

Comparisons of the steady-state and transient particle 

simulations are based on differences in the (1) horizontal flow 

direction,

1 (2) ending depth, (3) net distance traveled, and 

(4) average linear velocity (table 20) of the particles. In most 

cases, particles move along one general direction and the flow 

path is described by a single compass direction. Where the 

particles followed an irregular path the flow path is described 

with multiple compass directions. The net distance traveled 

was calculated as the straight-line distance between the 

starting and ending locations of the particles. The ending depth 

for all particles is model layer 1 unless indicated otherwise. 

Average linear velocity was calculated as the net distance 

traveled divided by travel time, in this case 10 years. In the 

following discussion, the values for net distance traveled 

and average linear velocities are presented first for particle 

simulations during steady-state flow followed by particle 

simulations during transient flow. 

Recharge from Irrigation—Particles A, B, C

The steady-state and transient A particles traveled about 

7.3 and 6.9 mi, respectively, southeast, south, and southwest, 

with the transient particle ending about 0.2 mi northwest 

of the steady-state pathline (fig. 38; table 20). The average 

linear velocities were 11 and 10 ft/d. The initial southeast 

flow direction was perpendicular to the regional groundwater 

flow direction and was caused by groundwater moving 

toward hydrogeologic zone 4 (fig. 38), a zone with a large 

hydraulic conductivity (HC). The shorter distance traveled 

by the transient particle resulted from the simulated decrease 

in hydraulic gradient northeast of the sinks during the early 

to mid 1980s. The gradient decrease was caused by a rise in 

water levels during the wet cycle of the early to mid 1980s 

(fig. 36). Water levels rose throughout the model area due 

to the large amount of streamflow infiltration from the Big 

Lost River, but the largest water-level rises were centered 

at the Big Lost River Sinks and spreading areas (fig. 36). 

This water‐level rise caused a decrease in hydraulic gradient

upgradient (north and east), and an increase in hydraulic 

gradient downgradient (south and west), of the sinks and 

spreading areas. The A particles moved downward to model 

layer 2, with most of the downward flow taking place in 

hydrogeologic zone 4. Downward flow in hydrogeologic zone 

4 indicates that simulated heads in this zone decrease with 

depth, reflecting the downward displacement effects of inflow 

across the northeast boundary, underflow from the Birch Creek 

alluvial aquifer, streamflow infiltration from Birch Creek 

diversions (fig. 14), and the larger HC of hydrogeologic zone 4 

relative to that of hydrogeologic zone 44 (fig. 21). 

The steady-state and transient B particles traveled 

south about 6.6 and 5.7 mi, with the transient particle ending 

about 0.2 mi east of the steady-state pathline. The average 

linear velocities were 9.5 and 8.2 ft/d. The transient particle 

traveled a shorter distance because of the simulated decrease 

in hydraulic gradient northeast of the Big Lost River Sinks 

during the early to mid 1980s. The B particles, although 

originating in hydrogeologic zone 4 at the center of model 

layer 1, moved downward to the bottom of model layer 1 

reflecting the downward displacement effects of upgradient 

inflow across the northeast boundary.

The steady-state and transient C particles traveled 

about 46.6 and 43.4 mi southwest, with the transient particle 

ending about 0.4 mi northwest of the steady-state pathline. 

The average linear velocities were 67.4 and 62.7 ft/d. The 

long distance these particles traveled reflects the large HC 

for hydrogeologic zone 1 (fig. 21). The transient particle 

traveled a shorter distance because of the simulated decrease 

in hydraulic gradient east of the sinks and northeast of the 

spreading areas during the early to mid 1980s.

1

Difference in horizontal flow direction, also defined as the particle divergence, is the perpendicular offset distance between the endpoint of the slowest 

particle and the pathline of the fastest particle.
100 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 38

A

B

E F

G

10-year steady-flow pathlines and identifier

1983-1992 transient-flow pathlines and identifier

Model area boundary

A

A

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Mud Lake

Big Lost River

spreading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

PIONEER MOUNTAINS

Atomic

City

Howe

Arco

Mud

Lake Terreton Big Lost River

Sinks and 

Playas

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.

K

M

C

4580

4560

4540

4520

4440

4420

4460

4480

4300

4400

4410

4600

4500

O

D

H I

N

J

L

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

EXPLANATION

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

 Hydrogeologic zones, model layer 1

1—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally less than 11 percent

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally less than 11 percent

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

4—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

11—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally more than 11 percent

22—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

44—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

6—Silicic rocks, including rhyolite domes and andesite

4500 Water-table contour—Shows altitude of water table, 

March–May, 1995. Intervals 10 and 100 feet. Dashed 

where approximately located. From Bartholomay and 

others (1997, figure 9). Datum is NGVD27. 

Figure 38. Pathlines representing 10-year particle-tracking simulations under steady-state and transient flow conditions, Idaho 

National Laboratory and vicinity, Idaho. Particles are labeled A through O.
Analysis of Advective Flow and Transport 101

Table 20. Summary comparison of particle divergence, net distances traveled, and average linear velocities at the end of a 

10-year simulation period under 1980 steady-state flow conditions and transient flow conditions from 1983 through 1992, Idaho 

National Laboratory and vicinity, Idaho.

[Particle divergence: The perpendicular offset distance between the endpoint of the slowest particle and the pathline of the fastest particle. Net 

distance traveled is the straight-line distance between a particle’s starting and ending locations. Percentages are (1) the particle divergence divided 

by the smaller net distance traveled and (2) the difference in net distance traveled divided by the larger net distance traveled. Average linear 

velocity: The net distance traveled in feet divided by travel time in days. Pathlines are shown in figure 38. Abbreviations: SS, steady-state; T, 

transient; mi, mile; ft/d, foot per day; BLR, Big Lost River; sa, Big Lost River spreading areas]

Particle Transient 

stress

SS and T 

particle 

divergence 

(mi)

SS and T 

particle 

divergence 

(percent)

Ending 

model 

layer 

(SS/T)

Net distance 

traveled 

(SS/T) 

(mi)

Difference in 

net distance 

traveled 

(percent)

Average linear 

velocity 

(SS/T) 

(ft/d)

A Irrigation 0.2 3 2/2 7.3/6.9 5 11/10

B Irrigation .2 4 1/1 6.6/5.7 14 9.5/8.2

C Irrigation .4 1 1/1 46.6/43.4 7 67.4/62.7

D BLR Playa .4 10 2/2 5.0/4.2 16 7.2/6.1

E BLR Sinks .2 1 1/1 23.9/17.0 29 34.5/24.6

F BLR Sinks .6 11 2/2 5.7/5.5 4 8.2/8.0

G BLR channel .3 11 1/1 3.1/2.7 13 4.5/3.9

H BLR channel .1 1 4/4 14.7/14.2 3 21.3/20.5

I BLR channel .2 20 1/1 1.3/1.0 23 1.9/1.4

J BLR channel .1 4 2/2 6.4/2.6 59 9.3/3.8

K BLR channel .1 4 1/1 12.2/2.5 80 17.6/3.6

L BLR sa .9 5 3/4 18.6/19.2 3 26.9/27.8

M BLR sa 1.7 8 2/2 26.1/22.3 15 37.7/32.2

N Wastewater .6 4 1/1 19.8/16.3 18 28.6/23.6

O Wastewater .2 11 1/1 2.0/1.8 10 2.9/2.6

Recharge from Big Lost River Playas and Sinks—

Particles D, E, F

The steady-state and transient D particles traveled about 

5.0 and 4.2 mi south, with the transient particle ending about 

0.4 mi west of the steady-state pathline (fig. 38; table 20). The 

average linear velocities were 7.2 and 6.1 ft/d. The differences 

in the net distance and direction traveled were caused by the 

transient particle initially traveling northwest. The northwest 

flow direction was caused by a short-term reversal in gradient 

from streamflow infiltration at Big Lost River Playa 3 in 1983. 

The D particles moved downward to model layer 2 reflecting 

the downward displacement effects of streamflow infiltration 

across the top of model layer 1 beneath Big Lost River Playa 3 

(fig. 13B).

The steady-state and transient E particles traveled 

about 23.9 and 17.0 mi south-southwest, with the transient 

particle ending about 0.2 mi west of the steady-state pathline 

(table 20). The average linear velocities were 34.5 and 

24.6 ft/d. The transient particle traveled a shorter distance 

because of the simulated decrease in hydraulic gradient north 

of the spreading areas resulting from the large amount of 

streamflow infiltration at the Big Lost River spreading areas 

during the early to mid 1980s (fig. 36).

The steady-state and transient F particles traveled 

about 5.7 and 5.5 mi south-southwest, with the transient 

particle ending about 0.6 mi west of the steady-state pathline 

(table 20). The average linear velocities were 8.2 and 8.0 ft/d. 

A more westerly orientation of the hydraulic gradient 

during the early to mid 1980s, caused by the large influx of 

streamflow infiltration at the Big Lost River Sinks and Playas 

(fig. 36), was responsible for the transient particle ending 

west of the steady-state particle. The downward displacement 

effects of recharge at the sinks also caused the F particles to 

move downward to model layer 2.

Recharge from Big Lost River Channel—Particles G, H, I, 

J, K

The steady-state and transient G particles traveled about 

3.1 and 2.7 mi south, with the transient particle ending about 

0.3 mi west of the steady-state pathline (fig. 38; table 20). The 

average linear velocities were 4.5 and 3.9 ft/d. The westerly 

movement of the transient particle, relative to the steady-state 

particle, was caused by a lack of streamflow infiltration from 

the Big Lost River channel from 1987 through 1992. The 

reduction in recharge resulted in a 1992 simulated water table 

beneath the Big Lost River south of the sinks that was about 5 

to 10 ft lower than initial conditions in 1980.
102 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

The steady-state and transient H particles initially 

traveled south-southeast, a direction that was influenced by 

underflow from the Big Lost River alluvial aquifer, before 

traveling south and southwest. The H particles traveled about 

14.7 and 14.2 mi southwest, with the transient particle ending 

about 0.1 mi northwest of the steady-state pathline (table 20). 

The average linear velocities were 21.3 and 20.5 ft/d. The 

shorter distance traveled by the transient particle was caused 

by the reduced gradient in this area during the dry-climate 

cycle. The H particles moved downward to model layer 4 

reflecting the downward displacement effects of underflow 

from the Big Lost River alluvial aquifer and streamflow 

infiltration from the Big Lost River (fig. 14).

The steady-state and transient I particles traveled about 

1.3 and 1.0 mi southwest, with the transient particle ending 

about 0.2 mi southeast of the steady-state pathline (table 20). 

The average linear velocities were 1.9 and 1.4 ft/d. Streamflow 

infiltration at the Big Lost River spreading areas during 1983 

and 1984 produced a decrease in the simulated hydraulic 

gradient northeast of the spreading areas (fig. 36) and caused 

the transient particle to travel a shorter distance than the 

steady-state particle. The transient particle traveled south of 

the steady-state particle because the small amount of recharge 

from the Big Lost River channel between 1987 and 1992 

resulted in a 1992 simulated water table beneath the INTEC 

that was about 3–4 ft lower than in the steady-state simulation 

and resulted in a shift of the water-table gradient toward a 

more southerly direction.

The steady-state and transient J particles traveled 

about 6.4 and 2.6 mi southwest, with the transient particle 

ending about 0.1 mi northwest of the steady-state pathline 

(table 20). The average linear velocities were 9.3 and 3.8 ft/d. 

The distance the transient particle traveled was influenced 

by streamflow infiltration from the Big Lost River during 

the early to mid 1980s and a lack of recharge during the 

mid 1980s to early 1990s. Recharge produced a decrease 

in the hydraulic gradient upgradient of the river, and the 

lack of recharge produced a decrease in hydraulic gradient 

downgradient of the river. The decreases in hydraulic gradient 

influenced the velocity of the transient particle. The J particles 

from both simulations moved downward to model layer 2 

reflecting the downward displacement effects of streamflow 

infiltration from the Big Lost River (fig. 14).

The K steady-state particle traveled south-southwest and 

southwest about 12.2 mi and the transient particle traveled 

about 2.5 mi south-southwest (table 20). The average linear 

velocities were 17.6 and 3.6 ft/d. The extreme difference in 

distance traveled was caused by the (1) simulated decrease 

in hydraulic gradient northeast of the spreading areas during 

the early to mid 1980s (fig. 36), which slowed the velocity of 

the transient particle; and (2) earlier arrival of the steady-state 

particle in hydrogeologic zone 1, which has an HC about 50 

times larger than that of hydrogeologic zone 11 (fig. 21).

Recharge from Big Lost River Spreading Areas—

Particles L, M

The steady-state and transient L particles traveled about 

18.6 and 19.2 mi southwest, with the steady-state particle 

ending about 0.9 mi northwest of the transient pathline 

(fig. 38; table 20). The average linear velocities were 26.9 

and 27.8 ft/d. The 14 to 16 ft increase in hydraulic head 

beneath the spreading areas from 1981 through 1984 (fig. 36) 

caused the transient particle to travel farther south than the 

steady‐state particle. The steady-state and transient particles

moved downward to model layers 3 and 4, respectively, 

reflecting the downward displacement effects of streamflow 

infiltration across the top of model layer 1 beneath the 

spreading areas. The large amount of recharge from the 

spreading areas in 1983 and 1984, with a subsequent increase 

in simulated vertical head gradients, increased downward 

flow in the aquifer beneath the spreading areas and resulted 

in the transient particle ending at a greater depth than the 

steady‐state particle

The steady-state and transient M particles traveled about 

26.1 and 22.3 mi southwest, with the transient particle ending 

about 1.7 mi east of the steady-state pathline (table 20). 

The average linear velocities were 37.7 and 32.2 ft/d. The 

differences in distance and direction resulted from the 10 to 

12 ft increase in head east and south of the spreading areas 

from 1981 through 1984 (fig. 36). The increased head, and 

the resulting decrease in the hydraulic gradient east of the 

spreading areas, caused the transient particle to travel slower 

than, and farther east of the steady-state particle. The M 

particles from both simulations moved downward to model 

layer 2 reflecting the downward displacement effects of 

streamflow infiltration from the Big Lost River and spreading 

areas.

Wastewater Discharge at RTC and INTEC—Particles N, O

The steady-state and transient N particles originated 

about 0.25 mi southwest of the RTC infiltration ponds and 

traveled west, southwest, south, southeast, and then southwest 

19.8 and 16.3 mi (fig. 38; table 20). The average linear 

velocities were 28.6 and 23.6 ft/d. The initial westerly flow 

direction of these particles was caused by a gradient that was 

influenced by wastewater discharge at the RTC infiltration 

ponds and the large HC of hydrogeologic zone 1 to the 

west. The southwest, south, and southeast flow directions 

resulted from the particles moving around the perimeter of 

hydrogeologic zone 11, a zone with a small HC. The particles 

moved along the perimeter of zone 11 because little flow 

exited zone 11 relative to the volume of flow within zone 1. 

The steady-state particle traveled about 3.5 mi farther than the 

transient particle because the particles traveled through the 

area northeast of the Big Lost River spreading areas during 

the simulated hydrologic conditions of the early 1980s. The 
Analysis of Advective Flow and Transport 103

hydraulic head in this area increased by about 8–10 feet 

between 1981 and 1984 (fig. 36), decreasing the hydraulic 

gradient, and causing the transient particle to move slower 

than the steady-state particle. The transient particle ended 

0.6 mi northwest of the steady-state pathline because the 

particles traveled south of the spreading areas while water 

levels were declining beneath the spreading areas during the 

late 1980s and early 1990s (fig. 38). The declining water table 

beneath the spreading areas shifted the gradient in this area 

toward a more northerly direction.

The steady-state and transient O particles originated 

about 0.5 mi south of the INTEC disposal well (CPP 3) 

and traveled about 2.0 and 1.8 mi south, with the transient 

particle ending about 0.2 mi west of the steady-state pathline 

(table 20). The average linear velocities were 2.9 and 2.6 ft/d. 

The transient particle traveled slower than the steady-state 

particle because the hydraulic gradient decreased due to 

recharge at the spreading areas during the early to mid 1980s. 

The transient particle traveled slightly west of the steady-state 

particle because of wastewater discharge, beginning in 1984, 

at the INTEC infiltration ponds, about 0.1 mi east of the of the 

O particle origination point.

Evaluation of Transient Flow Influence on 

Particle Paths

The 1 to 4 percent divergence of the A, B, and C 

steady-state and transient pathlines and the relatively 

small differences in net distance traveled, 5 to 14 percent, 

(table 20) indicates that irrigation withdrawals and return 

flows do not have a large influence on particle flow directions 

and velocities. Particle flow directions and net distance 

traveled were not influenced by irrigation because irrigation 

withdrawals and return flows were (1) about equal, so the 

net recharge from irrigation was about zero; (2) seasonal, 

but relatively constant on an annual basis from 1981 through 

1995; and (3) distributed fairly uniformly over a large area, 

which resulted in a small average irrigation-infiltration flux 

of about 0.4 (ft3/s)/mi2 (Ackerman and others, 2006, p. 34), 

compared to the average infiltration flux of 20 (ft3/s)/mi2

(Ackerman and others 2006, p. 34) from the Big Lost River. 

Consequently, head differences with time resulting from 

irrigation withdrawals and return flows were small and broadly 

distributed.

The large, concentrated fluxes of streamflow infiltration 

from the Big Lost River Sinks, Playas, and spreading areas 

influenced the movement of particles across a large part of 

the INL. Particles that traveled near these recharge centers, 

such as the D, F, L, M, and N particles, were influenced more 

by streamflow infiltration than particles that remained far 

from the recharge centers, such as the A, B, and H particles. 

The relatively smaller concentrated fluxes of streamflow 

infiltration from the Big Lost River channel only influenced 

the movement of particles near the channel. The influence of 

this recharge on particle flow direction and travel distance, 

however, was large as shown by the 11–20 percent divergence 

for particle pairs G and I and the 13 to 59 percent difference 

in net distance traveled for particle pairs G, I, and J (table 20). 

The effect of episodic streamflow infiltration on particle paths 

was partly masked in these simulations because the transient 

simulation included wet- and dry-climate cycles. During the 

early to mid 1980s, wet cycle recharge from the Big Lost 

River caused rises in the water table, with the largest rises 

centered at the recharge locations. During the mid 1980s to 

early 1990s dry cycle the water table declined, with the largest 

declines centered at the recharge locations. Consequently, 

changes in particle directions and velocities that were a 

result of the persistent rise in the water table were partly 

counteracted by the subsequent decline in the water table.

The concentrated flux of wastewater discharge at the RTC 

and the INTEC influenced the movement of particles within 

about 1 mi of these facilities. This small area of influence 

may result from the (1) complex hydraulic gradients near 

the facilities because of large groundwater withdrawal fluxes 

adjacent to large wastewater discharge fluxes and (2) larger 

annual groundwater withdrawal than annual wastewater 

discharge at these facilities. Local influence of wastewater 

discharge on particle movement was evident from the 

initial westerly movement of the N particles. This westerly 

movement was partly influenced by wastewater discharge 

at the RTC, and was different from the regional southwest 

direction of groundwater flow. However, the initial movement 

of the steady-state and transient particles was similar because 

of the relatively constant wastewater discharge rate at the 

RTC from 1980 through 1995. The 11 percent divergence of 

the steady-state and transient O particles (table 20) near the 

INTEC resulted from the relocation in 1984 of wastewater 

discharge from the INTEC disposal well (CPP 3) to the 

INTEC infiltration ponds, 0.5 mi south of the disposal well. 

This relocation affected the transient particle, but did not 

affect the steady-state particle because the steady-state particle 

moved in response to simulated 1980 hydrologic conditions. 

Differences in net distance traveled were 18 and 10 percent 

for particle pairs N and O, respectively. These differences 

resulted from streamflow infiltration at the Big Lost River 

spreading areas and, in the case of particle O, from relocation 

of wastewater disposal from CPP 3 to the INTEC infiltration 

ponds in 1984.

Transient and steady-state average linear particle 

velocities ranged from 1.4 to 67.4 ft/d (table 20). This 

large variability in particle velocities was caused mainly by 

geographic variability in hydraulic properties, however, and 

not by variability of recharge. The primary reason particle 

velocities varied so much was the 1.7 order-of-magnitude 

range of simulated HC values for the hydrogeologic zones 

(table 9). The factor of five range of model values for 

effective porosity (0.03 to 0.15, table 19) and the 1.3 orderof‐magnitude range of simulated hydraulic gradients (from

about 2.3 to 80 ft/mi; fig. 23) also influenced particle 

velocities. For example, velocities of 4.5 ft/d or slower were 

calculated for particles G, I, and O (table 20). These particles 
104 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

remained entirely within the small-HC area of hydrogeologic 

zone 11. The F particles also remained entirely within 

hydrogeologic zone 11, but the slightly faster F particle 

velocities (8.0 and 8.2 ft/d) were attributed to recharge at the 

Big Lost River Sinks that increased the hydraulic gradient 

(fig. 38). The J particle velocities were 3.8 and 9.3 ft/d, and 

these particles traveled entirely within hydrogeologic zone 

2, a zone with a small HC. However, the large difference in 

velocity between the J particles was attributed to variable 

streamflow infiltration. Velocities ranging from 6.1 to 11 ft/d 

were calculated for particles A, B, and D. These particles 

traveled primarily within hydrogeologic zone 44, a zone with 

a small HC, but particles A and B also traveled partly through 

hydrogeologic zone 4, which has a large HC. The velocities 

calculated for the K particles were 3.6 and 17.6 ft/d. The 

slower velocity was calculated from a K particle that remained 

entirely within zone 11, and the faster velocity was calculated 

from a K particle that traveled a long distance in zone 1. The H 

particles traveled through hydrogeologic zones 2 and 3, which 

have a small HC. The velocities calculated for the H particles, 

21.3 and 20.5 ft/d, were faster than expected for travel through 

these zones and reflect the steeper hydraulic gradient in the 

ESRP aquifer at the mouth of the Big Lost River (fig. 22), a 

result of the large amount of underflow recharge from this 

tributary valley. Velocities of 24 ft/d or faster were calculated 

for particles C, E, L, M, and N. These particles traveled long 

distances through hydrogeologic zone 1, with the fastest 

velocities (62.7–67.4 ft/d) calculated for the C particles, which 

traveled almost exclusively in hydrogeologic zone 1.

Representativeness of Flow Directions and 

Average Linear Particle Velocities

The representativeness of the simulated particle flow 

directions and average linear velocities was evaluated by 

comparing (1) steady-state flow directions to a contour map of 

1995 water-table altitudes and (2) steady-state average linear 

particle velocities to independent average linear groundwater 

velocity estimates based on the tritium/helium-3 (3H/3He) 

and chlorofluorocarbon (CFC) model ages of the young 

fraction of groundwater and assumed first and peak arrivals of 

chlorine-36 (36Cl) at selected wells in geographic proximity to 

the simulated pathlines (table 21; fig. 39).

The 1995 water-table contours used in this comparison 

depict the shape of the water table at the end of a long dry 

cycle. Even though the water table rises and falls over time 

in response to variable recharge, these contours are believed 

to be a reasonable representation of the water table because 

the general shape of the water table is relatively stable 

(Ackerman and others, 2006, p. 39). Particle velocities 

derived from the steady-state flow simulation were used in 

this comparison because these particles were not influenced 

by episodic streamflow infiltration and therefore, were more 

representative of long-term aquifer conditions. Independent 

velocity estimates used in this comparison were calculated 

based on the straight-line or minimum distance from the 

point of origination to the point of observation and represent 

minimum velocities that do not take into account the tortuosity 

of the pathway. The reliability of velocity estimates based on 

assumed peak and first arrivals is limited by the sensitivity of 

the analytical detection limit and the frequency of sampling 

prior to a confirmed detection. In almost all cases, first-arrival 

estimates likely occur after the actual first arrival; therefore, 

velocity estimates based on assumed first arrival times should 

be viewed as minimum velocities. 

Most simulated particle paths seem to be reasonable 

because the particles moved in directions perpendicular or 

nearly perpendicular to the 1995 water-table contours (fig. 38). 

The only particle paths that seem inconsistent are those 

associated with the A particles. These particles moved in a 

direction parallel to the 4,580 ft water-table contour before 

tracking southward across hydrogeologic zone 4 and in a 

direction parallel to the regional direction of groundwater 

flow. As noted in the section, Comparison of Simulated and 

Observed Steady-State Heads head observations are sparse in 

the northwestern part of the model area near the Birch Creek 

alluvial aquifer underflow boundary and are insufficient to 

result in improved agreement between simulated and observed 

heads in this area. The orientation of the simulated 4,600 ft 

head contour (fig. 23) reflects a complex interplay of inflows 

from multiple sources that does not reflect the general shape 

of the water table in this area as defined by the limited data 

available.

The steady-state particle velocities and independently 

derived velocity estimates ranged from 1.9 to 67.4 ft/d 

(table 20; fig. 38) and 1.6 to 33 ft/d (table 21; fig. 39), 

respectively. A geographic comparison indicates that particle 

velocities (1) within hydrogeologic zone 11 were slightly 

slower than independent estimates, (2) within hydrogeologic 

zone 1 were much faster than independent estimates, and 

(3) within other hydrogeologic zones were faster than 

independent estimates. 

For example, steady-state velocities for particles F and 

G, located entirely within hydrogeologic zone 11, were 8.2 

and 4.5 ft/d, respectively (table 20), and were slightly slower 

than the 10 to 14 ft/d velocity estimates to well USGS 17 near 

and south of the Big Lost River Sinks (fig. 39). The velocities 

for particles C and M, located entirely within hydrogeologic 

zone 1, were 67.4 and 37.7 ft/d, respectively. The velocity 

for particle C was 2 to 4 times the 16 and 33 ft/d velocity 

estimates to wells USGS 1 and USGS 100 for the southeast 

part of the model area, and the velocity for particle M was 

about 2 to 3 times the maximum velocity estimates of 15.9 and 

11.9 ft/d to wells USGS 11 and USGS 14 south of the INL. 

The velocity for particle D, mostly within hydrogeologic zone 

44, was 7.2 ft/d, 3 times the estimated velocity of 2.3 ft/d to 

well PSTF Test near TAN. Similarly, the 9.3 ft/d velocity for 

particle J, within hydrogeologic zone 2, was nearly 3 times the 

3.3 and 3.6 ft/d estimated velocity to wells USGS 7 and USGS 

86 near the west INL boundary. 
Analysis of Advective Flow and Transport 105

Table 21. Average linear groundwater velocities calculated based on tritium/helium-3 and chlorofluorocarbon model ages of 

the young fraction of groundwater and assumed first and peak arrivals of chlorine-36, between selected wells, Idaho National 

Laboratory and vicinity, Idaho.

[Velocity traces are shown in figure 39. Method: 3H/3He, Busenberg and others (2001); CFC, Busenberg and others (2001); 36Cl, Cecil and others (2000). 

Abbreviations: 3H/3He, tritium/helium-3; CFC, chlorofluorocarbon; 36Cl, chlorine-36; 18O, oxygen-18; BLR, Big Lost River; INTEC, Idaho Nuclear 

Technology and Engineering Center; USGS, U.S. Geological Survey; LLR, Little Lost River; NRF, Naval Reactors Facility; yr, year; σ, sigma; ft/d, foot 

per day; ±, plus or minus; –, no information]

Well

Method

Source Velocity

(ft/d)

Young fraction

from 18O

(percent ±1σ)

3

H/3He CFC 36Cl 

Age 

(yr) ±1σ Age (yr)

First arrival Peak arrival

Time (yr) Time (yr)

USGS 1 – – 26–28 – – Mud Lake-Terreton 33 43 ± 7

USGS 5 16.5 0.5 – – BLR Sinks 10.8 47 ± 8

16.3 .3 – – BLR Sinks 10.8

USGS 8 8.4 .2 – – BLR channel 3.3 44 ± 7

USGS 9 21.3 .6 – – INTEC disposal well 6.9 38 ± 6

22.7 .4 – – INTEC disposal well 6.2

USGS 11 17.3 .3 – – INTEC disposal well 12.5 37 ± 6

13.61 – INTEC disposal well 15.9

25.7 INTEC disposal well 8.4

USGS 12 2.9 .4 – – LLR underflow 4.9 62 ± 10

4.5 .4 – – LLR underflow 3.9

USGS 14 27.3 .5 – – INTEC disposal well 9.2 53 ± 9

19.31 INTEC disposal well 11.9

 – 28.5 INTEC disposal well 8.1

USGS 17 16.1 .3 – – BLR Sinks 9.8 54 ± 9

11.1 .3 – – BLR Sinks 14.4

USGS 86 12.1 .5 – – BLR channel 3.6 26 ± 6

USGS 97 6.3 .5 – – NRF 3.3 56 ± 9

USGS 98 6.7 1.3 – – NRF 6.6 29 ± 5

USGS 99 3.9 .2 – – NRF 8.2 33 ± 6

USGS 100 23–24 – – Mud Lake-Terreton 16 44 ± 7

USGS 102 5.7 .2 – – NRF ditch 1.6 59 ± 10

USGS 103 26.1 .4 – – INTEC disposal well 4.3 41 ± 7

USGS 1052 – – INTEC disposal well 6.2 41 ± 7

USGS 109 20.0 .4 – – INTEC disposal well 6.2 45 ± 8

17.7 .4 – – INTEC disposal well 7.2

USGS 121 15.5 .6 – – NRF 5.2 48 ± 8

USGS 124 23.7 .1 – – INTEC disposal well 7.5 36 ± 6

23.6 .5 – – INTEC disposal well 7.5

USGS 125 17.0 .3 – – INTEC disposal well 10.2 43 ± 7

Cross Road3 13.1 .4 – – BLR spreading areas 9.8

NPR Test 13.9 .4 – – BLR Sinks 14.1 47 ± 8

PSTF 9.3 2.2 – – Birch Creek Playa 2.3 51 ± 9

1

 USGS 11 36Cl greater than 1.5 times background; USGS 14 36Cl greater than 1.8 times background. 2

 Busenburg and others (2001, fig. 25).

3

 Plummer and others (2000).
106 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Figure 39. Flow directions and average linear groundwater velocities based on tritium/helium-3 and chlorofluorocarbon 

model ages of the young fraction of groundwater and assumed first and peak arrivals of chlorine-36 at selected wells, 

Idaho National Laboratory and vicinity, Idaho.

ID19-0164_GWflow_fig.39

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

1:100,000. Universal Transverse Mercator projection, Zone 12; 

North American Datum of 1927.

Big Lost River

speading areas

A, B, C, and D

Big Lost River

sinks and playas

1, 2, and 3

2

1 3

A

B

A

C, D

Mud

Lake

Birch

Big

Lost

River

Little

Lost

River

Creek

LEMHI RANGE

LOST RIVER RANGE

East

Butte

Middle

Butte

Atomic

City

Big

Southern

Butte

Arco

PSTF TEST 

2.3 ft/d

USGS 102

1.6 ft/d USGS 97

3.3 ft/d

USGS 98

5.2 ft/d

USGS 99

8.2 ft/d

USGS 121

5.2 ft/d

USGS 1001

16 ft/d

USGS 11

33 ft/d

USGS 12

3.9-4.9 ft/d USGS 17

9.8-14.4 ft/d

USGS 5

10.8 ft/d

NPR Test

14.1 ft/d

USGS 86

3.6 ft/d

USGS 9

6.2-6.9 ft/d

USGS 125

10.2 ft/d

CROSS ROAD 3

9.8 ft/d

USGS 11

12.5 ft/d

(8.4-15.9 ft/d)2 

USGS 8

3.3 ft/d

USGS 103

4.3 ft/d

USGS 14

9.2 ft/d (8.1-11.9 ft/d)2

USGS 124

7.5 ft/d

USGS 105

6.2 ft/d

USGS 109

6.2-7.2 ft/d

TAN

RTC

INTEC

NRF

MFC

RWMC

CFA

113°00’

44°

00’

43°

30’

43°

45’

112°45’ 112°30’

113°15’

0 10 Miles

0 10 Kilometers

EXPLANATION

Site facilities

Idaho National Laboratory boundary

USGS 12

5 ft/d

Well in the USGS water-level monitoring network and

 identifier with calculated groundwater flow velocity,

 in feet per day (ft/d)

Groundwater-flow direction based on location of well

 sampled and interpreted source of groundwater

Modified from Busenberg and others, 2001, fig. 25. 

Footnotes:

All velocity estimates based on 3H/3He dating of young fraction 

(Busenberg and others, 2001) except as noted.

1 Velocity based on chlorofluorocarbon dating of young fraction 

(Busenberg and others, 1993)

2 Velocities based on peak arrival and assumed first arrival of 36Cl 

(Cecil and others, 2000)

3 Velocity based on 3H/3He dating of young fraction (Plummer and 

others, 2000)

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

Mud

Lake Terreton

Howe
Analysis of Advective Flow and Transport 107

Comparison of Flow During a Wet- and a 

Dry-Climate Cycle

The extended wet- and dry-climate cycles of the 1980s 

and 1990s produced large differences in streamflow infiltration 

to the ESRP aquifer in the model area, and provided an 

opportunity to examine the influence of this climate-controlled 

recharge on the movement of groundwater beneath the INL. 

To investigate this influence, particle tracking was used 

to simulate groundwater movement under transient flow 

conditions for 4 years during a wet cycle and for 4 years 

during a dry cycle. The wet-cycle particle-tracking simulations 

were run from 1983 through 1986. This period included the 

last 4 years of a 5-year wet cycle (1982 through 1986) and 

included the 2-year period (1983 and 1984) with the largest 

recorded annual mean discharges onto the INL (fig. 10). The 

starting time for this simulation was selected to emphasize the 

influence of streamflow infiltration on particle flow directions, 

velocities, and depths. The dry-cycle particle-tracking 

simulations were run from 1989 through 1992. This period 

was part of an 8-year dry cycle that lasted from 1987 through 

1994 and included a 4-year period when the Big Lost River 

did not flow onto the INL (fig. 10). The starting time for this 

simulation, 2 years following the wet-cycle simulation, was 

selected to minimize residual (or antecedent) effects from the 

previous wet-cycle simulation. 

Analysis of Flow Paths During a Wet- and a 

Dry-Climate Cycle

Particles were released at the beginning of the wet‐cycle

and dry-cycle simulations at the same particle release 

locations as described in the section Analysis of Steady-State 

and Transient Flow Paths. The particles were tracked and the 

resulting particle paths were plotted as pathlines (fig. 40). 

Although these particle-tracking simulations were designed 

to evaluate the influence of streamflow infiltration on particle 

movement, the discussion of the particle paths follows the 

same organization as the previous section, where particles 

were grouped together based on the proximity of particle 

starting locations to a particular transient stress. The same 

features of the particle pathlines were evaluated and the same 

calculations (table 22) made for net distance traveled and 

average linear particle velocity as described in the previous 

section. In the following discussion the (1) ending depth for 

all particles is model layer 1 unless indicated otherwise and 

(2) values for net distance traveled and average linear velocity 

are presented first for the wet-cycle simulation followed by the 

dry-cycle simulation.

Effects of Irrigation during a Wet- and a Dry-Climate 

Cycle—Particles A, B, C

The A particles traveled about 2.5 mi southeast, with 

the wet-cycle particle ending about 0.1 mi northeast of the 

dry‐cycle pathline (fig. 40; table 22). Both average linear

velocities were 9.0 ft/d. The small change in the flow 

directions of the A particles was caused by the different 

amounts of recharge at the sinks during the wet and dry cycles 

and the resulting differences in hydraulic head and gradient in 

the northern part of the INL (fig. 36).

The B particles traveled about 4.2 and 4.4 mi southsouthwest, with the wet-cycle particle ending about 0.3 mi 

east of the dry-cycle pathline. The average linear velocities 

were 15 and 16 ft/d. The small change in the flow directions 

and distances of the B particles was caused by the different 

amounts of recharge at the sinks during the wet and dry 

cycles and the resulting differences in hydraulic head and 

gradient in the northeastern part of the INL (fig. 36). The C 

particles traveled along nearly identical paths about 15.1 and 

15.6 mi southwest. The average linear velocities were 54.6 

and 56.4 ft/d. The shorter travel distance of the C wet-cycle 

particle was caused by the large amount of recharge at the 

spreading areas and sinks during the wet-climate cycle, which 

produced a slight rise in water levels and a coincident decrease 

in hydraulic gradient in the eastern part of the INL (fig. 36).

Effects of Recharge at Big Lost River Playas and Sinks 

during a Wet- and a Dry-Climate Cycle—Particles D, E, F

The D wet-cycle particle initially traveled northwest in 

response to a pulse of recharge and rising water levels at Big 

Lost River Playa 3 in 1983, before traveling south-southeast 

and south. The dry-cycle particle traveled south. The wet-cycle 

particle ended about 0.2 mi east of the dry-cycle pathline. The 

net travel distance of the wet-cycle particle was about 1.3 mi, 

or about 0.9 mi less than the dry-cycle particle. The average 

linear velocities were 4.7 and 8.0 ft/d. 

The E particles traveled about 3.5 and 2.8 mi southsouthwest, with the dry-cycle particle ending about 0.5 

mi southeast of the wet-cycle pathline. The average linear 

velocities were 13 and 10 ft/d. The different flow direction and 

the longer travel distance of the wet-cycle particle were caused 

by an increase in hydraulic head and gradient in response to 

recharge at the sinks (fig. 36).

The F particles traveled about 3.0 mi south-southwest 

and 1.8 mi south-southeast, about a 45-degree difference in 

flow directions. The dry-cycle particle ended about 1.5 mi 

east of the wet-cycle pathline, and traveled south-southeast in 

response to a local hydraulic gradient influenced by alluvial 

aquifer underflow from the Little Lost River valley. Recharge 

at the sinks was responsible for the south-southwest flow 

direction and the longer distance traveled by the wet-cycle 

particle. The average linear velocities were 11 and 6.5 ft/d.
108 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Figure 40. Pathlines representing particle-tracking simulations for a 4-year wet cycle (1983 through 1986) and a 4-year 

dry cycle (1989 through 1992) under transient flow conditions, Idaho National Laboratory and vicinity, Idaho. Particles 

marked A through O.

ID19-0164_GWflow_fig. 40

Wet-cycle pathlines and identifier

Dry-cycle pathlines and identifier

Model area boundary

A

A

East

Middle Butte

Butte

Big Southern

Butte

Little Lost River

Big Lost River

Birch

Creek

Snake River

Mud Lake

Big Lost River

speading areas

A, B, C, and D

Little Lost River

Birch

Creek

TAN

RTC

INTEC

RWMC CFA

MFC

NRF

BITTERROOT

RANGE

LOST RIVER RANGE

LEMHI RANGE

Atomic

City

Howe

Arco

Mud

Lake Terreton

D

H I

N

O J

L

A

B

C

E F

G

M

K

0 10 20 Miles

0 10 20 Kilometers

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

113°30'

44°

00'

43°

45'

43°

30'

43°

15'

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

EXPLANATION

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

MFC—Materials and Fuels Complex

NRF—Naval Reactors Facility

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

 Hydrogeologic zones, model layer 1

1—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally less than 11 percent

2—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally less than 11 percent

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

4—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent

11—Younger rocks consisting of densely fractured basalt and interbedded sediment, 

with a sediment thickness of generally more than 11 percent

22—Younger rocks consisting of massive, less densely fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

44—Intermediate-age rocks consisting of slightly altered fractured basalt and 

interbedded sediment, with a sediment thickness of generally more than 11 percent

6—Silicic rocks, including rhyolite domes and andesite

PIONEER MOUNTAINS

Big Lost River

Sinks and 

Playas

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.
Analysis of Advective Flow and Transport 109

Table 22. Summary comparison of particle divergence, distances traveled, and average linear velocities at the end of simulations for a 

wet cycle (1983 through 1986) and a dry cycle (1989 through 1992), Idaho National Laboratory and vicinity, Idaho.

[Particle divergence: The perpendicular offset distance between the endpoint of the slowest particle and the pathline of the fastest particle. Net distance 

traveled: The straight-line distance between the particle’s starting and ending locations. Percentages are the particle divergence divided by the smaller net 

distance traveled and the difference in net distance traveled divided by the larger net distance traveled. Average linear velocity: The net distance traveled in feet 

divided by travel time in days. Pathlines are shown in figure 40. Abbreviations: W, wet climate cycle; D, dry climate cycle; mi, mile; ft/d, foot per day; BLR, 

Big Lost River; sa, Big Lost River spreading areas]

Particle Transient stress

W and D particle divergence Ending model 

layer (W/D)

Net distance 

traveled (W/D) 

(mi)

Difference in net 

distance traveled 

(percent)

Average linear 

velocity (W/D) 

(ft/d) (mi) (percent)

A Irrigation 0.1 4 1/1 2.5/2.5 0 9.0/9.0

B Irrigation .3 7 1/1 4.2/4.4 5 15/16

C Irrigation .1 1 1/1 15.1/15.6 3 54.6/56.4

D BLR Playa .2 15 1/1 1.3/2.2 41 4.7/8.0

E BLR Sinks .5 18 1/1 3.5/2.8 20 13/10

F BLR Sinks 1.5 83 1/1 3.0/1.8 40 11/6.5

G BLR channel .3 27 1/1 1.5/1.1 27 5.4/4.0

H BLR channel .1 3 2/2 4.6/4.0 13 17/14

I BLR channel .2 40 1/1 0.5/0.5 0 1.8/1.8

J BLR channel .1 10 1/1 1.1/1.0 9 4.0/3.6

K BLR channel .2 33 1/1 0.8/0.6 25 2.9/2.2

L BLR sa 1.1 12 3/2 9.3/9.4 1 34/34

M BLR sa 1.8 14 2/1 13.1/13.6 4 47.3/49.1

N Wastewater .2 18 1/1 1.1/1.2 8 4.0/4.3

O Wastewater .3 50 1/1 0.8/0.6 25 2.9/2.2

Effects of Recharge along Big Lost River during a Wetand a Dry-Climate Cycle—Particles G, H, I, J, K

The G wet-cycle particle traveled about 1.5 mi south and 

the dry-cycle particle traveled about 1.1 mi south-southwest, 

with the dry-cycle particle ending about 0.3 mi west of the 

wet-cycle pathline. The average linear velocities were 5.4 

and 4.0 ft/d. The difference in flow direction was caused by 

more recharge from the Big Lost River channel during the wet 

cycle, which caused the hydraulic gradient east of the channel 

to be slightly more eastward than during the dry cycle. The 

difference in distance traveled was caused by more recharge 

from the Big Lost River Sinks during the wet cycle, which 

increased the hydraulic gradient south of the sinks (fig. 36).

The H particles traveled about 4.6 and 4.0 mi 

south‐southeast and south, with the dry-cycle particle ending

about 0.1 mi east of the wet-cycle pathline. The average linear 

velocities were 17 and 14 ft/d. The wet-cycle particle traveled 

farther because of a slight increase in hydraulic gradient 

caused by the large amount of recharge at the spreading areas 

(fig. 36). The H particles moved downward to model layer 2 in 

response to the downward displacement effects of underflow 

from the Big Lost River alluvial aquifer and streamflow 

infiltration from the Big Lost River (fig. 14).

 The I particles traveled about 0.5 mi southwest, with the 

dry-cycle particle ending about 0.2 mi southeast of the wetcycle pathline. Both average linear velocities were 1.8 ft/d. 

The more westerly flow direction of the wet-cycle particle 

was caused by a slight directional change in gradient due to 

increased recharge from the Big Lost River channel southeast 

of the particles.

The J particles traveled about 1.1 and 1.0 mi southwest, 

with the dry-cycle particle ending about 0.1 mi southeast of 

the wet-cycle pathline. The average linear velocities were 

4.0 and 3.6 ft/d. The wet-cycle particle traveled farther and 

slightly more west than the dry-cycle particle because of the 

large amount of recharge at the spreading areas and the slight 

directional change in gradient produced by the recharge.

The K particles traveled about 0.8 mi south and 0.6 mi 

southwest, with the dry-cycle particle ending about 0.2 mi 

west of the wet-cycle pathline. The average linear velocities 

were 2.9 and 2.2 ft/d. The wet-cycle particle traveled farther 

and slightly more east than the dry-cycle particle because of 

increased recharge from the Big Lost River channel about 1 

mi to the northwest and a slight directional change in gradient 

produced by the recharge.
110 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Effects of Recharge at Big Lost River Spreading Areas 

during a Wet- and a Dry-Climate Cycle—Particles L, M

The L particles traveled about 9.3 mi southwest, with 

the wet-cycle particle ending about 1.1 mi southeast of the 

dry‐cycle pathline. The average linear velocities were 34 ft/d.

The particle directions diverged because the direction of the 

local hydraulic gradient varied in response to streamflow 

infiltration to the aquifer from the spreading areas (fig. 36). 

The wet- and dry-cycle particles traveled downward to 

model layers 3 and 2, respectively, reflecting the downward 

displacement effects of streamflow infiltration beneath the 

spreading areas across the top of model layer 1. The deeper 

movement of the wet-cycle particle was caused by the 

increased recharge at the spreading areas during the wet-cycle.

The M particles traveled about 13.1 and 13.6 mi 

southwest, with the wet-cycle particle ending about 1.8 mi 

southeast of the dry-cycle pathline. The average linear 

velocities were 47.3 and 49.1 ft/d. The wet-cycle particle 

traveled farther southeast than the dry-cycle particle because 

of the increased recharge at the spreading areas during the wet 

cycle. The wet-cycle particle moved downward to model layer 

2 and the dry-cycle particle remained in model layer 1. The 

downward movement of the wet-cycle particle was caused by 

the increased recharge at the spreading areas during the wet 

cycle.

Effects of Wastewater Discharge at RTC and INTEC 

during a Wet- and a Dry-Climate Cycle—Particles N, O

The N particles traveled about 1.1 and 1.2 mi west, 

with the wet-cycle particle ending about 0.2 mi north of the 

dry-cycle pathline. The average linear velocities were 4.0 and 

4.3 ft/d. The westerly flow direction was not coincident with 

the regional flow direction and reflected a local hydraulic 

gradient controlled by (1) wastewater discharge about 0.3 

mi to the northeast at the RTC waste infiltration ponds and 

(2) and an increase in HC. Hydrogeologic zone 1, about 1.1 mi 

west of the particle release point has a much larger HC than 

hydrogeologic zone 11, in which the particles were released 

(fig. 40). The wet-cycle particle traveled north of the dry-cycle 

particle because of a slightly more northerly orientation to the 

local hydraulic gradient resulting from streamflow infiltration 

in the Big Lost River channel about 1 mi to the southeast.

The O particles traveled about 0.8 mi south and 0.6 mi 

southwest, with the dry-cycle particle ending about 0.3 mi 

west of the wet-cycle pathline. The average linear velocities 

were 2.9 and 2.2 ft/d. The difference in flow direction and 

the longer distance traveled by the wet-cycle particle was 

caused by a shift in the direction of the hydraulic gradient 

and an increase in the hydraulic gradient resulting from the 

larger amount of streamflow infiltration in the Big Lost River 

channel during the wet-cycle. 

Evaluation of Short-Term Climate Cycles 

Influence on Particle Paths

Irrigation had minimal influence on the travel direction 

and distance of the A, B, and C particles. The small particle 

divergences of 1 to 7 percent and differences in net distance 

traveled of 0 to 5 percent (table 22) for these particles were 

caused by differences in the amount of streamflow infiltration 

at the Big Lost River Sinks and spreading areas during the 

wet- and dry-climate cycles. Because these particles are 

12–13 mi distant from the sinks and more than 20 mi from 

the spreading areas, these results may indicate that episodic 

recharge at the sinks or spreading areas can influence 

groundwater movement over a fairly large area, a simulation 

result that seems to be supported by observed water-level rises 

and declines between 1981 and 1998 (fig. 12).

Differences in recharge at the Big Lost River Playas 

and Sinks corresponding to wet- and dry-climate cycles 

substantially affected the travel directions and distances of the 

D, E, and F particles. The divergence of these particles ranged 

from 15 to 83 percent, and the difference in net distance 

traveled ranged from 20 to 41 percent. Differences in recharge 

at the sinks and playas affected the F particles the most, 

because these particles originated closest to the sinks (fig. 40).

Variable recharge from the Big Lost River channel caused 

large divergences (27–40 percent) for the G, I, and K particles 

and a large difference in net distance traveled (25 percent) for 

the G and K particles. Even though the influence of recharge 

from the channel is probably limited to a distance of a few 

miles from the channel, the influence of recharge on these 

particles was large because they traveled short distances 

(1.5 mi or less; table 22) and remained within about 1 mi 

of the channel and in close proximity to the source of the 

transient stress throughout the simulation period.

Differences in recharge at the spreading areas caused a 

moderate divergence of 12–14 percent, but only a 1–4 percent 

net difference in distance traveled, for the L and M particles. 

Recharge was expected to have a greater influence on particle 

movement for particles traveling near such a concentrated 

recharge center as the spreading areas. The lesser influence 

was caused by the large HC of hydrogeologic zone 1, the zone 

underlying the spreading areas. Divergence of the particles 

was relatively small because the large HC allowed for rapid 

movement of water beneath the spreading areas (L and M 

particle velocities ranged from 34 to 49 ft/d; table 22), relative 

to the movement of water beneath the sinks (E and F particle 

velocities ranged from 6.5 to 13 ft/d). As a result, the water 

table beneath the spreading areas rose much less than the 

water table beneath the sinks during the wet cycle (fig. 36). 

The large HC for hydrogeologic zone 1 also influenced the 

small percentage differences in net distance traveled, because 

these percentage differences were minimized by the long 

distances the particles traveled (9.3–13.6 mi; table 22).
Analysis of Advective Flow and Transport 111

Flow directions and velocities for the N and O particles 

were influenced by (1) wastewater discharged at the RTC 

and INTEC, (2) large differences in HC between adjacent 

hydrogeologic zones, and (3) variable streamflow infiltration 

from the Big Lost River channel. These influences on particle 

movement illustrate the complexity of flow beneath the RTC 

and the INTEC. The effects of short-term climate cycles 

on N and O particle paths were subdued by the large HC 

of hydrogeologic zone 1 and by the volume of wastewater 

discharged at the RTC and the INTEC. Consequently, only 

episodic recharge from the river channel caused divergence or 

differences in net distance traveled for the N and O particles. 

The divergence (50 percent; table 22) and difference in 

net distance traveled (25 percent) for the O particles were 

relatively large because of the short distance traveled by these 

particles and the close proximity of the particles to the river 

channel (fig. 40).

The wet- and dry-cycle particle paths (table 22) were 

compared to the steady-state and transient particle paths 

(table 20) to evaluate how episodic recharge affects short‐term

(one wet- or dry-climate cycle) and long-term (multiple wetand dry-climate cycles) advective transport. Considering just 

the K, L, M, N, and O particles, the particles that traveled 

in the southwestern part of the INL where contaminants are 

most prevalent in the aquifer, the percent divergences ranged 

from 12 to 50 percent for the wet-cycle/dry-cycle particles 

(table 22) and from 4 to 11 percent for the steady-state/

transient particles (table 20). Differences in net distance 

traveled between wet-cycle/dry-cycle and steady-state/

transient particles were compared only for the O particles. For 

the other starting locations, particles simulated under different 

conditions traveled through several HC zones, complicating 

the evaluation of the effects of episodic recharge. The 

differences in net distance traveled for the wet-cycle/dry-cycle 

and steady-state/transient O particles were 25 and 10 percent, 

respectively. These differences in particle divergence and 

net distance traveled illustrate how the proximity of the 

particles to recharge areas influenced the results. The wet- and 

dry‐cycle particles typically traveled one-half the distance or

less of the steady-state and transient particles, which meant 

that the wet- and dry-cycle particles remained closer to the 

recharge areas that were the source of change in the local 

hydraulic gradient. The farther away from recharge areas that 

particles moved, the less influence those recharge areas had 

on particle flow directions and velocities. The length of time 

that particle paths were simulated also influenced the results. 

The effect of episodic streamflow infiltration on these particles 

was large during short simulation periods that coincide with 

wet- or dry-climate cycles, but this effect was diminished 

over longer simulation periods that included both wet- and 

dry‐climate cycles

Evaluation of Flow and Transport in the 

Southwestern Part of Idaho National Laboratory 

Particle tracking was used to simulate the growth of 

tritium (3H) plumes at the INTEC and RTC over a 16-year 

period under steady-state conditions (1980) and over a 16-year 

period under transient conditions (1953 through 1968). These 

simulations were used to evaluate the representativeness 

of simulated groundwater flow directions and average 

linear velocities in that part of the aquifer most affected by 

contamination. 

The 2-D shape, dimensions, and areal extent of these 

simulated plumes are compared to maps of the 1968 3H 

plumes in the aquifer (fig. 41) that originated at the INTEC in 

1953 and at the RTC in 1952. In this analysis, model-derived 

particle velocities are compared to groundwater velocity 

estimates that are based on (1) the assumed position and an 

extended definition of the position of the leading edge of 

the 3H plumes in 1968 (fig. 41; table 23), (2) the peak and 

assumed first arrivals of 3H and 36Cl at downgradient wells, 

and (3) the 3H/3He model ages of the young fraction of 

groundwater at downgradient wells.

The assumed position of the leading edge of the 3H 

plume is defined by 3H concentrations greater than 2,000 

pCi/L in 1968. The extended definition of the position of the 

leading edge is based on a comparison of the shape of the 

concentration gradients used to define the leading edge of the 

1968 and 1985 3H plumes. Peak-arrival velocity estimates are 

based on a time-lagged correlation of monthly 3H releases at 

the INTEC disposal well with semi-annual concentrations of 

3H at USGS 36. First-arrival velocity estimates are based on 

3H detections at monitoring wells CFA 2, USGS 90, 103, 105, 

and 108; and 36Cl detections at USGS 11 and 14. Velocity 

estimates for 3H/3He are based on the model ages of the young 

fraction of groundwater at USGS 103, 105, 108, 109, 124, and 

125 (fig. 41).

Model-derived average linear groundwater velocities are 

based on the (1) transient travel times of multiple particles 

released in model layer 1 and 2 cells at the location of the 

INTEC disposal well (CPP 3) and in model layer 1 cells at the 

location of the INTEC disposal pit and the RTC warm-waste 

ponds (fig. 41), and (2) steady-state travel times of a single 

particle released in the center of a model layer 2 cell at the 

location of the INTEC disposal well.

Several assumptions, approximations, and simplifications 

were made for this analysis, including:

• [assumption] The 3H plumes represent a continuum 

wherein 3H is assumed to be dispersed throughout 

the water-filled pore space encompassed within the 

boundaries of the plume. 
112 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. 41

Big Lost River

speading areas

A, B, C, and D

Big Southern

Butte

Big Lost River

20 26

22

23

88

26

20

Sample in May 1968

Well

Sample only in October 1985

No sample history or constructed after 1985

Well number (USGS well)

EXPLANATION

Model area

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

Line of equal tritium concentration in picocuries per liter times 

1,000—May, 1968, dashed where approximately located. Interval 

variable. Modified from Robertson and others (1974, fig. 71c)

Line of equal tritium concentration in picocuries per liter times 

1,000—October, 1985. Interval variable. Modified from Pittman 

and others (1988, fig. 29)

25

2

124

B B' Tritium concentration gradient line

RTC

INTEC

RWMC

CFA

Atomic

City

2

25

25

2

50

50

100

100 100

150

200

200

0.5

2

125

124

110

109 108

107

106

83

105

104

103

90

36

14

11

9

RWMC EBR 1

PROD

CPP 3

CFA 2

Badging

Facility

OMRE Site 9

112°58'0'' 112°57'30''

43°

35'

30''

43°

35'

0''

TRA 2 TRA 3

TRA 1 TRA 4

Cold-waste

ponds

Warm-waste ponds

Chem-waste

ponds

TRA DISP

RTC

43°

34'

30''

43°

34'

0''

112°56'30'' 112°56'0'' 112°55'30''

CPP 3

Disposal

pit

CPP 1

CPP 2

CPP 4

Infiltration

ponds

INTEC

B

B'

113°10' 113°05' 112°55' 112°50'

43°

35'

43°

20'

43°

25'

43°

30'

0 5 Miles

0 5 Kilometers

113°00'

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.

Figure 41. Location of tritium concentrations greater than 2,000 and 500 picocuries per liter, in 1968 and 1985, respectively, 

and monitoring wells used to compare model-derived average linear groundwater velocities to independently derived 

velocities, Idaho National Laboratory and vicinity, Idaho. 
Analysis of Advective Flow and Transport 113

Table 23. Measured tritium concentrations used to define the 

leading edge of the tritium plume in 1968 and 1985, Idaho National 

Laboratory and vicinity, Idaho.

[Locations of wells are shown in figure 41 and appendix B. Analytical 

detection limit for 1968 is 2 pCi/mL and for 1985 is 0.5 pCi/mL. Values in 

bold indicate reportable detection. Abbreviations: pCi/mL, picocurie per 

milliliter, σ, sigma; <, less than]

Well

May 1968 October 1985

Tritium 

(pCi/mL)

Counting 

error

(2σ)

Tritium 

(pCi/mL)

Counting 

error

(2σ)

USGS 83 9 4 0.0 0.6

USGS 901 1.6 .3

USGS 103 .4 .6

USGS 104 .9 .6

USGS 105 .0 .6

USGS 106 2.7 .8

USGS 107 .1 .6

USGS 108 .8 .6

USGS 109 .2 .6

EBR 1 < 2 .1 .6

OMRE 4 2 2.6 .8

RWMC PROD 1.4 .3

SITE 9 < 2 .0 .6

1

 January 1985.

• [approximation] The true areal extent, shape, and 

dimensions of the 3H plumes at any point in time 

are known only to the extent that well coverage and 

analytical detection limits in use at the time will allow. 

• [assumption] The 2-D areal distribution of 3H and 

the boundaries of the 3H plumes are defined by 3H 

concentrations that represent mixtures of water, 

derived from various depths in open wells (in some 

cases pumped samples and in other cases thief or 

submerged bailer samples) that are assumed to be 

uniform with depth. 

• [approximation] The transition from facility-derived 3H 

to background concentrations is represented by a sharp 

boundary or concentration isopleth even though the 

true boundary, particularly along the forward or leading 

edge of the plume, likely lies within a diffuse transition 

zone where facility-derived 3H concentrations 

gradually merge with and become indistinguishable 

from background2 levels. The shape of this boundary, 

although depicted as smooth and continuous, is likely 

to be very irregular and even may be discontinuous, 

reflecting the effects of preferential flow in an aquifer 

characterized by extreme heterogeneity and anisotropy. 

• [assumption] The reliability of assumed first arrival 

times, upon which independent velocity estimates are 

based, is limited by the sensitivity of the analytical 

detection limit and its ability to distinguish background 

concentrations from facility-derived concentrations, 

and the frequency of sampling prior to a confirmed 

detection. In almost all cases, first arrival estimates 

likely are after the actual first arrival; therefore, first 

arrival time estimates should be viewed as maximum 

travel times and velocity estimates as minimum 

velocities.

• [simplification] Velocity estimates, based on simulated 

travel times and the assumed first arrivals of 3H and 

36Cl at downgradient wells, are calculated on the basis 

of the straight-line or minimum distance from point 

of origination to point of observation and represent 

minimum velocities that do not take into account the 

tortuosity of the pathway.

• [approximation] Particles were released within cell 

blocks that are 0.25 × 0.25 mi (width by length) 

and dimensionally much larger than the physical 

dimensions of the disposal pits, ponds, and wells 

that were used to dispose of wastewater. Modeling 

3H releases in this manner was a restriction imposed 

from using the uniform cell discretization of the 

steady-state and transient flow models. Substantial 

evidence suggests, however, that because of lateral 

flow in the unsaturated zone, inflows to the aquifer 

from the INTEC disposal pit and RTC warm-waste 

ponds probably occur over a substantially larger area 

than indicated by the surface expression of these 

disposal sites (Robertson and others, 1974; Wood and 

Norrell, 1996; Nimmo and others, 2002). In a study 

to explain the processes controlling the longitudinal 

and transverse dimensions of the tritium plume 

downgradient of the INTEC, Duffy and Harrison 

(1987, p. 900) concluded that the radial spreading 

effect of wastewater injection into the INTEC disposal 

well probably extended about 450 m (0.28 mi) outward 

from the well. 

2

In 1968, elevated background concentrations of 3H (half life = 12.26 years) in the aquifer beneath the spreading areas, the Big Lost River channel, sinks, 

and playas, derived mostly from above-ground testing of nuclear weapons in the late 1950s and early 1960s, (3H concentrations in the atmosphere peaked in 

1964) may have been as high as 1,900–6,300 pCi/L from streamflow infiltration in 1964 (6,300 pCi/L), 1965 (5,800 pCi/L), and 1967 (1,900 pCi/L). Away from 

areas of rapid focused recharge, these background levels probably ranged from about 160 to 320 pCi/L, representing recharge prior to the 1964 peak. These 

estimates are based on (1) a model of 3H concentrations that assumes the residence time of water in streams recharging the aquifer is 1 year and the age of the 

young fraction is “... greater than 5 years but less than 40 years” and (2) measured concentrations of 3H in wells at the INL from 1994 to 1996 that were shown 

not to be contaminated with facility-derived 3H (Busenberg and others, 2001, p. 25, figs. 15, 16). In 1989, 3H concentrations in water from 19 springs near Twin 

Falls, Idaho (fig. 1), were less than about 0.2 pCi/mL and from 12 irrigation and domestic wells, 65 mi south of the INL, were less than the reporting level to 

0.1 pCi/mL (or 615–307 pCi/L when decay corrected to 1968) (Mann and Cecil, 1990, p. 11). 
114 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Although the hydrogeologic zones used to represent 

the aquifer are assumed to be adequately represented as 

homogeneous, anisotropic porous media at the scale of 

this analysis, small-scale heterogeneity within individual 

hydrogeologic zones is not represented and likely has 

an appreciable if not a large influence on dispersion of 

contaminants released at the INTEC and RTC. Because of this 

limitation, the particle plume simulations do not incorporate 

the effects of small-scale tortuosity and likely underestimate 

the full extent of dispersion. 

Particle-Tracking Simulation Scenarios for 

Tritium Releases at INTEC and RTC, 1953–68

Background information used for the steady-state and 

transient particle-plume simulations is summarized in table 24. 

Major differences between the 1953–68 historical 3H release 

scenario and the simulated particle-plume scenarios included 

simulating the (1) temporally variable 3H releases during 

the historical period as constant discrete particle releases 

at the beginning of each simulation year and (2) downward 

percolation of 3H in wastewater discharged to the INTEC 

disposal pit and RTC warm-waste ponds during the historical 

period as instantaneous particle releases to the aquifer.

The steady-state particle-tracking simulations are 

based on groundwater fluxes derived from calibration of 

the steady-state model. These fluxes are constant for each 

steady-state stress period. Groundwater fluxes are variable 

in the transient simulation and reflect the effects of temporal 

variations in wastewater disposal, groundwater withdrawals, 

and streamflow infiltration from one stress period to another. 

To facilitate comparisons of the particle tracking results the 

timing, location, and number of particle releases were identical 

in the steady-state and transient simulations.

Comparison of Historical Tritium Releases (1953–1968) and 

Simulated Particle Releases at the INTEC and RTC

From 1952 through 1968, an estimated 21,000 curies (Ci) 

of 3H were discharged in wastewater at the RTC and INTEC 

(figs. 42A, B, and D; table I1). At the INTEC, 16,000 Ci 

were disposed of in a 20-in. diameter, 600-ft deep, gravelpacked well (CPP 3) (fig. 41) at inflow depths of 412–452 and 

489–592 ft below land surface and 400 curies in a disposal pit 

(INTEC disposal pit), 0.3 mi south of CPP 3 and about 450 ft 

above the water table. At the RTC, 4,400 Ci were disposed 

of in wastewater infiltration ponds (warm-waste ponds) also 

about 450 ft above the water table. Annual releases at the 

INTEC during this period were highly variable, ranged from 

100 to 3,500 Ci/yr, and averaged 1,000 Ci/yr (Robertson 

and others, 1974). Peak releases at the INTEC occurred in 

1958 (3,500 Ci) and 1959 (2,500 Ci). Annual releases at the 

RTC over this period were fairly uniform, ranged from 20 to 

500 Ci/yr, and averaged 280 Ci/yr (table I1). 

In the models, particles were released at the INTEC 

disposal well, the INTEC disposal pit, and the RTC warmwaste ponds to simulate 3H releases at these two facilities from 

1953 through 1968. Small amounts of tritium were released at 

the RTC in 1952, but were not considered important enough to 

extend the duration of the simulation period to 17 years. 

Particles were released at equally spaced points defined 

by a 3 × 3 array (440 ft between release points) across the 

four vertical faces of model cell blocks in model layers 1 and 

2 to simulate the inflow depths of wastewater injected into 

the INTEC disposal well. Particles also were released across 

the four vertical faces of model cell blocks in model layer 1 

at the INTEC disposal pit and the RTC warm-waste ponds 

to simulate inflow of wastewater from the ground surface. In 

the steady-state and transient particle-tracking simulations, 

36 particles (9 particles across each cell face) were released 

in each model cell block at the beginning of each year in 

which tritium was released to the aquifer (fig. 42). During the 

16-year simulation period, 2,124 particles were released in the 

steady‐state and transient simulations.

Releasing particles within the vertical cell faces rather 

than distributing the particles within a model cell allows the 

plume of particles to reach its full extent while minimizing 

the number of particles released in a simulation. For example, 

a particle released from a cell face has a greater potential for 

describing the outer range of plume movement compared 

with a particle released from within a model cell. Although an 

increase in the number of particles provides greater accuracy 

in defining particle plume movement, the tradeoff is an 

increase in the computational burden associated with the use 

of additional particles.

Because flow through the unsaturated zone is treated 

implicitly in the numerical flow models, particles released at 

INTEC disposal pit and the RTC warm-waste ponds entered 

the flow field at the water table instantaneously with no 

provision to account for the delay time for wastewater to 

infiltrate through the 450-ft thick unsaturated zone at these 

facilities. This limitation probably has minimal effect on the 

representativeness of simulation results. Field experiments 

in 1999 at the spreading areas and in 1994 at the Large-Scale 

Infiltration Test (LSIT) site, about 1 mi east of the spreading 

areas and 1 mi south of the RWMC (fig. 41), indicate that 

water infiltration rates beneath surface-water impoundments 

that receive substantial amounts of inflow ranged from 

16 ft/d (Wood and Norrell, 1996) at the LSIT site to as much 

as 72 ft/d (Nimmo and others, 2002, p. 95) at the spreading 

areas. These experiments indicate that under pondedinfiltration conditions the sedimentary interbeds and any other 

stratigraphic units expected to impede vertical flow in the 

unsaturated zone are not an effective barrier.
Analysis of Advective Flow and Transport 115

Table 24. Summary of tritium disposal, wastewater disposal, and groundwater withdrawals at the Idaho Nuclear Technology and 

Engineering Center and the Reactor Technology Complex used to simulate the growth of tritium plumes in the eastern Snake River Plain 

aquifer under steady-state conditions from 1980 and transient flow conditions from 1953 to 1968, Idaho National Laboratory, Idaho.

[Locations of facilities, disposal wells, production wells, disposal pit, and warm-waste ponds are shown in figure 41. Tritium disposal, wastewater discharge, 

and groundwater withdrawal estimates are given in appendix A. Abbreviations: INTEC, Idaho Nuclear Technology and Engineering Center; RTC, Reactor 

Technology Complex; Ci, Curies; Ci/yr, Curies per year; L, model layer; ft, foot; bls; below land surface; ft3/s, cubic foot per second]

Tritium and particle releases

Historical tritium releases (1952–68)

Facility Total tritium 

releases (Ci)

Annual release rates (Ci/yr) Release location Release depths (ft-bls) 

or (model layer) Calendar years Range Average

INTEC 16,000 100–3,500 1,000 CPP 3 412–452 1953–68

CPP 3 489–592 1953–68

400 12–190 65 Disposal pit Ground surface 1954–60, 1962–66

RTC 4,000 20–500 280 Warm-waste ponds Ground surface 1952–68

Simulated particle releases

Steady-state and transient simulations

Total particle 

releases

Particles per 

release

Number 

of particle 

releases

INTEC 576 36 16 CPP 3 L1

540 36 15 CPP 3 L2

432 36 12 Disposal pit L1

RTC 576 36 16 Warm-waste ponds LI

Wastewater disposal

Historical (1952–68)

Facility

Annual discharge rates (ft3

/s) Discharge 

location

Discharge depths 

(ft-bls) or 

(model layer)

Calendar or 

number of 

years Range Average

INTEC 0.8–1.8 1.3 CPP 3 412–452 1953–68

 CPP 3 489–592 1953–68

0.002–0.034 .017 Disposal pit Ground surface 1954–60, 1962–66

RTC 0.019–0.757 .421 TRA DISP 512–697 1964–68

935–1,005 1964–68

1,045–1,070 1964–68

0.064–1.2 .692 Warm-waste 

ponds

Ground surface 1952–68

Simulated

Steady-state (average for 1966–80) simulation

INTEC 1.694 CPP 3 L1,2 16 yrs L1 = 82 percent; L2 = 18 percent

0 Disposal pit

RTC 2.008 TRA DISP L1,2,4 16 yrs L1 = 63 percent; L2 = 32 percent; 

L4 = 5 percent

.241 Warm-waste 

ponds

Top of L1 16 yrs L1 = 100 percent

Transient (1953–68) simulation

INTEC 1.271 CPP 3 L1,2 1953–68 L1 = 82 percent; L2 = 18 percent

.013 Disposal pit Top of L1 1953–68 L1 = 100 percent

RTC .132 TRA DISP L1,2,4 1953-68 L1 = 63 percent; L2 = 32 percent; 

L4 = 5 percent

.692 Warm-waste 

ponds

Top of L1 1953-68 L1 = 100 percent
116 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Groundwater withdrawals

Historical (1953–68)

Facility

Annual withdrawal rates (ft3

/s) Withdrawal 

location

Withdrawal depths 

(ft-bls) or 

(model layer)

Calendar or

number of

Range Average years

INTEC 0.44–0.92 0.67 CPP 1 460–577 1953–68

0.64–0.93 .74 CPP 2 458–600 1953–68

RTC 0.55–2.31 1.38 TRA 1 480–580 1952–68

0–0.97 .18 TRA 2 558–601 1952–63

0.49–1.72 1.27 TRA 3 470–592 1957–68

TRA 4 900–965 1963–68

Simulated

Steady-state (1966–80 average) simulation

INTEC 0.883 CPP 1 L1,2 16 yrs L1 = 72 percent; L2 = 28 percent

.883 CPP 2 L1,2 16 yrs L1 = 43 percent; L2 = 57 percent

.060 CPP 4 L1,2,3 16 yrs L1 = 40 percent; L2 = 40 percent; 

L3 = 20 percent

RTC .223 TRA 1 L1,2 16 yrs L1 = 78 percent; L2 = 22 percent

.024 TRA 3 L1,2 16 yrs L1 = 67 percent; L2 = 33 percent

2.504 TRA 4 L4 16 yrs L4 = 100 percent

Transient (1953–68) simulation

INTEC 0.730 CPP 1 L1,2 1953–1968 L1 = 72 percent; L2 = 28 percent

.757 CPP 2 L1,2 1953–1968 L1 = 43 percent; L2 = 57 percent

RTC 1.026 TRA 1 L1,2 1953–1968 L1 = 78 percent; L2 = 22 percent

.576 TRA 2 L1,2 1953–1968 L1 = 8 percent; L2 = 92 percent

.982 TRA 3 L1,2 1953–1968 L1 = 67 percent; L2 = 33 percent

.334 TRA 4 L4 1953–1968 L4 = 100 percent

Table 24. Summary of tritium disposal, wastewater disposal, and groundwater withdrawals at the Idaho Nuclear Technology and 

Engineering Center and the Reactor Technology Complex used to simulate the growth of tritium plumes in the eastern Snake River Plain 

aquifer under steady-state conditions from 1980 and transient flow conditions from 1953 to 1968, Idaho National Laboratory, Idaho.—

Continued

[Locations of facilities, disposal wells, production wells, disposal pit, and warm-waste ponds are shown in figure 41. Tritium disposal, wastewater discharge, 

and groundwater withdrawal estimates are given in appendix A. Abbreviations: INTEC, Idaho Nuclear Technology and Engineering Center; RTC, Reactor 

Technology Complex; Ci, Curies; Ci/yr, Curies per year; L, model layer; ft, foot; bls; below land surface; ft3/s, cubic foot per second]
Analysis of Advective Flow and Transport 117

ID19-0164_GWflow_fig. 42

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

1.0

1.4

1.8

Wastewater disposal, in cubic feet per second 

Wastewater

Tritium

A. INTEC Disposal well (CPP 3)

0

50

100

150

200

Tritium disposal,

in curies per year

0.0

0.2

0.2

0.4

0.6

0.6

0.8

B. INTEC Disposal pit 1953 1954 1955 1956 1957 1958

1959196019611962196319641965196619671968

0.0

0.4

0.8

1.2

1.6

2.0

2.2

2.4

Water withdrawals, in cubic feet per second 

C. INTEC Production wells

0

400

800

1,200

1,600

2,000

2,400

2,800

3,200

3,600

Tritium disposal, in curies per year

D. RTC Warm-waste ponds

E. RTC Disposal well (TRA DISP)

F. RTC Production wells 1953 1954 1955 1956 1957 1958

1959196019611962196319641965196619671968

Wastewater

Tritium

CPP 1

Year Year

CPP 2

TRA 1

TRA 2

TRA 3

TRA 4

Wastewater

Tritium

Wastewater

Figure 42. Annual amount of tritium discharged in wastewater, annual wastewater disposal, and annual groundwater 

withdrawals, Idaho Nuclear Technology and Engineering Center and Reactor Technology Complex, 1953–1968, Idaho National 

Laboratory, Idaho. The location and other information for each well are available in tables A1 and I1 and figures B6 and B7.
118 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Comparison of Steady-State and Transient Wastewater 

Discharges and Groundwater Withdrawals at 

INTEC and RTC

In the steady-state simulation, wastewater discharges 

and groundwater withdrawals are based on 1966–80 average 

values. In the transient simulation wastewater discharges and 

groundwater withdrawals are based on semi-annual averages 

from 1953–68. These inflows and outflows are constant for 

each four-month transient stress period within a simulation 

year (fig. 42; table I1).

From January 1953 through February 1984, most of the 

low-level radioactive and chemical wastewater generated at 

the INTEC was discharged to the aquifer through the INTEC 

disposal well (CPP 3). During the early operational history 

of this well, 1953–66, much smaller quantities of low-level 

radioactive and chemical wastewater also were discharged to 

the INTEC disposal pit. The INTEC disposal well was taken 

out of routine service in 1984, used intermittently until 1986, 

permanently decommissioned in 1989, and replaced with two 

wastewater infiltration ponds about 0.5 mi south of the INTEC 

disposal well.

In the steady-state simulation, wastewater discharged 

to the INTEC disposal well averaged 1.694 ft3/s and was 

simulated as inflow to the model layer 1 (82 percent) and 2 (18 

percent), corresponding to the location of the open intervals 

in the disposal well (table 24). In the transient simulation, 

the rate of wastewater discharged from the INTEC disposal 

well averaged 1.271 ft3/s and was allocated to the model layer 

1 and 2 cells in the same proportions as in the steady-state 

simulation. 

In the steady-state simulation, no wastewater was 

discharged to the INTEC disposal pit. In the transient 

simulation, wastewater discharged to the INTEC disposal pit 

averaged 0.013 ft3/s and was simulated as recharge to the top 

of the model layer 1 cell corresponding to the location of the 

disposal pit.

Groundwater withdrawals from the INTEC production 

wells, about 0.4 mi north of the INTEC disposal well, 

averaged 1.826 ft3/s (CPP 1, 2, and 4) in the steady-state 

simulation and 1.487 ft3/s (CPP 1 and 2) in the transient 

simulation. In the transient simulation, water from these 

production wells was withdrawn from model layers 1 

(72 percent) and 2 (28 percent) for CPP 1 and model layers 1 

(43 percent) and 2 (57 percent) for CPP 2.

From 1952 through 1964, wastewater containing 

radioactive and non-radioactive waste was discharged to 

the warm-waste ponds at the RTC. Beginning in 1964, all 

non-radioactive wastewater was discharged to a 6- to 18–in. 

diameter, 1,267-ft deep well (TRA DISP) at inflow depths of 

512-697, 935-1,005, and 1,045-1,070 ft below land surface 

while radioactive wastewater continued to be discharged to the 

warm-waste ponds through 1982. In 1982, the deep disposal 

well was replaced with two cold-waste infiltration ponds.

In the steady-state simulation, wastewater discharged to 

the RTC disposal well averaged 2.008 ft3/s and was simulated 

as inflow to the model layer 1 (63 percent), 2 (32 percent), and 

4 (5 percent) cells corresponding to the location of the open 

intervals in the RTC disposal well. In the transient simulation, 

wastewater discharge averaged 0.132 ft3/s and was allocated to 

the model layer 1, 2, and 4 cells in the same proportions as in 

the steady-state simulation. 

In the steady-state simulation, the rate of wastewater 

discharged to the warm-waste ponds averaged 0.241 ft3/s and 

was simulated as recharge to the top of the model layer 1 cell 

corresponding to the location of the warm-waste ponds. In the 

transient simulation, the rate of wastewater discharged to the 

warm-waste ponds averaged 0.692 ft3/s.

Groundwater withdrawals from the RTC production 

wells, about 0.3 mi north of the TRA disposal well, averaged 

2.751 ft3/s (TRA 1, 3, and 4) in the steady-state simulation 

and 2.918 ft3/s (TRA 1, 2, 3, and 4) in the transient simulation. 

In the transient simulation water was withdrawn from model 

layers 1 (78 percent) and 2 (22 percent) for TRA 1, layers 1 

(8 percent) and 2 (92 percent) for TRA 2, layers 1 (67 percent) 

and 2 (33 percent) for TRA 3, and layer 4 (100 percent) for 

TRA 4.

Comparison of Steady-State and Transient 

Streamflow Infiltration

In the steady-state simulation, streamflow infiltration is 

based on 1966–80 average values that are constant for each 

stream reach and for every 12-month stress period (table C1). 

In the transient simulation streamflow infiltration is based on 

4-month averages from 1953–68 that generally vary for each 

4-month transient stress period (fig. 43; table C1). Differences 

in the timing, location, and amount of streamflow infiltration 

represent the major differences in hydrologic conditions 

between the 1980 steady-state and the 1953–68 transient 

particle-tracking simulations.

In the 16-year steady-state simulation, the annual mean 

discharge from 1966 through 1980 into the model area at 

Big Lost River near Arco (13132500; figs. 1 and 10) was 

119 ft3/s. The annual mean diversions to the spreading areas 

during this period was 43 ft3/s, the steady-state average based 

on discharge records at INL diversion at head near Arco 

(13132513; figs. 1 and 10). Prior to 1965, all streamflow 

infiltration from the Big Lost River was along the channel and 

at the sinks and playas near the west-central part of the INL. 

From 1966 through 1980, spreading-area diversions accounted 

for about 36 percent of the annual mean discharge into the 

model area. In the steady-state simulation, no distinction is 

made between a dry-climate and a wet-climate cycle. 
Analysis of Advective Flow and Transport 119

Figure 43. Annual mean discharge at (A) streamflowgaging station Big Lost River near Arco, and streamflow 

infiltration at (B) Big Lost River Sinks, Playas, and 

spreading areas, and from (C) model boundary to the 

Big Lost River Sinks, 1953 through 1968, Idaho National 

Laboratory and vicinity, Idaho.

ID19-0164_GWflow_fig. 43

0

100

200

0

100

200

0

100

200

300

400

Discharge, in cubic feet per second 

1953195419551956195719581959196019611962196319641965196619671968

EXPLANATION

Year

C. Reaches on the Big Lost River

A. Big Lost River near Arco (501)

Infiltration, cubic feet per second

Sinks and Playas (608–610) 

Spreading areas (602–605) 

B. Big Lost River Sinks, Playas, and spreading areas

Model Boundary to Big Lost River near Arco (600)

Big Lost River near Arco to INL Diversion (601)

INL Diversion to Lincoln Boulevard (606)

Lincoln Boulevard to Big Lost River Sinks (607)

Map numbers in parenthesis refer to identifiers used 

to locate streamflow-gaging stations and stream 

reaches described in appendix table A2, and located 

on maps in appendix figures B1, B2, with data 

provided in appendix table C1.

From 1953 through 1968, annual mean discharge into 

the model area at Big Lost River near Arco was 93 ft3/s 

and ranged from 0 to 343 ft3/s (fig. 43A; table C1). Peak 

annual mean discharges, substantially greater than the 16 

year average for this period and greater than the 1966–80 

steady-state average, 119 ft3/s, occurred in three intermittent 

years and ranged from 196 ft3/s in 1958 to 344 ft3/s in 1965 

(fig. 43A). The period from 1953 through 1968 included one 

2-year (1954–55) and one 4-year (1959–62) dry-climate cycle 

and one 3-year (1956–58) and one 6-year (1963–68) wetclimate cycle. The first diversions of streamflow from the Big 

Lost River to the spreading areas were in 1965 followed by 

diversions in each of the next 3 years. From 1965 through 

1968, diversions to the spreading areas ranged from 35 to 

159 ft3/s and averaged 87 ft3/s representing a total diversion 

of 1.1 × 1010 ft3 (251,940 acre-ft). From 1953 through 1968, 

streamflow infiltration from mean-annual spreading-area 

diversions averaged 22 ft3/s, or about 24 percent of the 

total streamflow into the model area at Big Lost River near 

Arco. On an annual basis, the streamflow infiltration rate at 

the spreading areas in the steady-state simulation is about 

twice as much as in the transient simulation; however, in the 

transient simulation this recharge is allocated over a 4-year 

period resulting in much higher recharge fluxes temporally and 

spatially.

Description and Comparison of Tritium and 

Particle Plumes

The 3H plumes are presented as a mapping of 

concentration isopleths that define the 2-D spatial distribution 

of 3H in the aquifer downgradient of the INTEC and the 

RTC in May 1968. Groundwater velocities are based on the 

inferred position of the 2,000 pCi/L isopleth that was used (or 

assumed) to define the leading edge of the 3H plume in 1968. 

For discussion, the simulated particle plumes are 

subdivided into segments that are based on the release 

location, release layer, and hydrogeologic zone or zones 

through which the particles traveled. The geographical 

position of each particle is plotted at the end of every 1-year 

simulation period and at every location where a particle 

crosses a cell face. This plotting approach is designed to track 

the entire history of each particle’s movement from time of 

release to the end of the 16-year simulation period. Simulated 

particle velocities are based on the position of the leading edge 

of each plume segment at various times during the simulation 

period.
120 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

3

 In 1968 and 1985, a tritium measurement was reported as a true detection if the measurement was greater than or equal to the analytical detection limit and 

greater than 2 times the counting uncertainty (95 percent probability that the true value is within ±2 sigmas). For measurements close to the analytical detection 

limit and (or) with counting uncertainties that approach the limiting value, this reporting criteria implies that there are 50 chances in 1,000 that the reported value 

is a false positive.

4

 The 1968 2,000 pCi/L isopleth south of USGS 83 (fig. 41) is based on an analysis of a thief sample of groundwater from this borehole in May 1968. Pumped 

samples from this borehole have never produced tritium concentrations greater than the reporting level despite the fact that boreholes south of USGS 83, along 

the southern boundary of the INL for example, have had positive detections in later years (Bartholomay and others, 2000). USGS 83 penetrates about 250 ft 

of the aquifer and is open from about 15 ft below the water table to total depth. Sampling in 1995 indicated that strontium and chlorofluorocarbon -11, -12, 

and -113 were anomalously low for this well given its location within the contaminant plume area. These anomalously low values and the lack of repeatable 

tritium detections above the analytical detection limit suggest that water pumped from this borehole does not come from the shallower parts of the aquifer where 

facility-derived tritium would normally be detected (Busenberg and others, 2001, figs. 5, 7, 8, 9 and p. 87).

5

 Tritium concentrations greater than local background levels, were first detected at USGS 103 (800 pCi/L) in July 1983, at USGS 105 (from less than the 

reporting level to 3,400 pCi/L with positive detections in 3 of 9 samples), and at USGS 108 (from 830 to 3,400 pCi/L with positive detections in 11 of 11 

samples) in October and November 1983 using a thief sampler. Repeat sampling of USGS 103 in October and November 1983 did not result in a reportable 

detection in 10 of 10 samples. Monitoring of these boreholes began in September 1980. In late November and early December 1983, the thief sampling system 

was replaced with dedicated submersible pumps and measured tritium concentrations declined in boreholes with positive detections in October and November 

1983, indicating nonuniform distribution of tritium in the aquifer and mixing of tritium over the 150–200 ft sampled intervals in these boreholes (Mann and 

Cecil, 1990, p. 27).

Tritium Plumes Downgradient of INTEC and 

RTC in 1968 and 1985

The areal extents of the 1968 3H plumes downgradient 

of the INTEC and RTC, as depicted by Robertson and others 

(1974), are shown in figure 41. Robertson’s depiction of the 

plume boundaries is based on 3H concentrations greater than 

2,000 pCi/L, the analytical detection limit3 in use at the time. 

The location of the 2,000 pCi/L isopleth in 1968 is based on 

very sparse well coverage and 3H non-detections that are a 

considerable distance away from the inferred 2,000 pCi/L 

isopleth, particularly along the southern4 (practically 

nonexistent) and much of the western and eastern boundaries 

of the mapped plumes (fig. 41). Additionally, locally elevated 

3H concentrations in the aquifer in 1968, derived from rapid 

focused recharge in the spreading areas, the Big Lost River 

channel, sinks, and playas in 1965 and 1967 may have been as 

high as 5,800 pCi/L4, implying that measured concentrations 

in areas affected by streamflow infiltration may include a 

substantial component of 3H, albeit diluted, from sources other 

than the INTEC and RTC, with uncertain implications for 

the mapped distribution of 3H that is assumed to be derived 

exclusively from wastewater disposal at the INTEC and RTC. 

In areas not affected by rapid focused recharge, background 

3H concentrations in 1968 would have ranged from about 

160 to 320 pCi/L4. In this case, detections would not have 

included a substantial component of 3H from non-facility 

sources; however, the analytical detection limit, 6 to 12 times 

greater than regional background, would not have been 

sufficiently sensitive to detect the absence (or near absence) of 

facility-derived 3H regardless of well coverage. The foregoing 

indicates that considerable uncertainty is associated with the 

location of the dashed boundary used to define the areal extent 

and assumed leading edge of the 3H plume in 1968 (fig. 41). 

Limitations of the analytical detection limit and their effect 

on interpretations of the extent of 3H in the aquifer were 

expressed by Robertson and others (1974, p. 170) who noted, 

The detection limit improved from 5 pCi/mL [5,000 

pCi/L] in 1963 to 2 pCi/mL [2,000 pCi/L] in 1966. 

This may lead to the mistaken impression that the 

outer fringe of the waste actually expanded to the 

extent indicated by the outer lines from 1963 to 

1966.

Also shown in figure 41 are the areal extents of the 1985 

3H plumes and the location of the 2,000 pCi/L isopleth as 

depicted by Pittman and others (1988). Pittman’s depiction of 

the plume boundaries is based on 3H concentrations greater 

than an analytical detection limit of 500 pCi/L and much 

improved, although still less than ideal, well coverage over 

that available in 1968. Pittman’s depiction of the leading 

edge includes 3H detections and non-detections in much 

closer proximity to the mapped 500 pCi/L isopleth than were 

available to map the 1968 2,000 pCi/L isopleth. In 1985, 

background concentrations of 3H in the aquifer in areas away 

from rapid focused recharge would have been about 165–200 

pCi/L for water representing recharge between 1945 and 

1980—water greater than 5 years old and less than 40 years 

old. In areas close to inputs of 3H from rapid focused recharge, 

concentrations would have been about 60–160 pCi/L based 

on a 1 year residence-time model for water in the Big Lost 

River that recharged the aquifer in 1982, 1983, and 19842

(Busenberg and others, 2001, fig. 16). The areal influence 

of these recharge events in the early 1980s on groundwater 

levels, and presumably their effect on 3H concentrations, was 

quite extensive as shown in the water-level rise map for July 

1981 to July 1985 (fig. 12).

From the foregoing, it can be inferred that the assumed 

leading edge of the 1985 3H plume probably was closer to its 

true position5 than the assumed leading edge of the 1968 3H 

plume. The leading edge of the 1985 3H plume would not have 

been as affected by limitations of well coverage, sensitivity of 

the analytical detection limit, or by ambiguity over the effect 

of regional background and locally elevated levels of 3H in the 

aquifer from non-facility sources. 
Analysis of Advective Flow and Transport 121

ID19-0164_GWflow_fig. 44

0

20

40

60

80

100

120

0 20,000 40,000 60,000 80,000 100,000

Tritium concentration, in picocuries per liter

Distance from disposal well CPP 3, in feet

May 1968 Plume

October 1985 Plume

USGS 103 -Velocity 4.3 ft/d for 15.4 yrs

USGS 105 -Velocity 6.2 ft/d for 15.4 yrs

USGS 109 -Velocity 7.2 ft/d for 15.4 yrs

USGS 103 -Velocity 4.3 ft/d for 32.8 yrs

USGS 105 -Velocity 6.2 ft/d for 32.8 yrs

USGS 109 -Velocity 7.2 ft/d for 32.8 yrs

EXPLANATION

Figure 44. Tritium concentration gradients defining the 

leading edge of the tritium plume downgradient of the 

Idaho Nuclear Technology and Engineering Center in 1968 

(2,000 pCi/L isopleth) and in 1985 (500 pCi/L isopleth), Idaho 

National Laboratory, Idaho. Theoretical positions of the 

leading edge based on tritium/helium-3-derived velocity 

estimates from the INTEC to wells USGS 103, USGS 105, 

and USGS 109, and travel times of 15.4 years and 32.8 years. 

Traces of concentration gradients are shown in figure 41. 

Velocity estimates are based on the tritium and helium-3 

ages of the “young fraction” of groundwater (Busenberg 

and others, 2001).

A comparison of the concentration gradients (fig. 44) 

for the 1968 and 1985 plumes along lines of section tracing 

downgradient concentrations towards the leading edge of 

the 1968 and 1985 plumes suggests that the inferred location 

of the 2,000 pCi/L isopleth in 1968 may have substantially 

underestimated the downgradient extent of facility-derived 3H 

in the aquifer. This underestimation was due to a combination 

of inadequate well coverage, unknown effects of mixing of 

3H from various sources, and constraints of the analytical 

detection limit as previously described. The shape of the 

1985 concentration gradient indicates a gradually varying and 

smooth transition leading into the 500 pCi/L isopleth that was 

used to define the leading edge of the 1985 plume, whereas 

the 1968 concentration gradient terminates abruptly at the 

assumed leading edge of the plume at a concentration that is 

6 to 12 times greater than the estimated regional background 

level (160–320 pCi/L). Calculated travel distances, in a 

constant velocity flow field, using 3H/3He‐derived velocity

estimates from the INTEC to wells USGS 103 (4.3 ft/d), 

USGS 105 (6.2 ft/d), and USGS 109 (7.2 ft/d) (fig. 39; 

table 21) and travel times of 15.4 years and 32.8 years indicate 

the theoretical position of the leading edge of the 3H plume 

in May 1968 and in October 1985 (fig. 44) for 3H releases at 

the INTEC disposal well (CPP 3) beginning in January 1953 

(fig. 42; table I1). The difference in the shape of the 1968 and 

1985 concentration gradients suggests that the downgradient 

extent of facility-derived 3H in 1968, attributable to advective 

flow, may have been several thousand to perhaps as much as 

10,000 ft south of the inferred 2,000 pCi/L isopleth before 

facility-derived 3H would have become indistinguishable from 

regional background levels, 160 to 320 pCi/L. This rendering, 

however, does not take into account the attenuating effects 

of radioactive decay (1.3 and 2.7 half-lives) for the initial 

releases of 3H that presumably would mark the leading edge 

of the 1968 and 1985 plumes, respectively. This rendering 

also does not account for the effects of locally elevated 

3H concentrations, a largely unknown complication that is 

presumed to have progressively less influence with increasing 

distance from areas of rapid focused recharge. A 10,000 ft 

difference represents an uncertainty of as much as 38 percent 

in groundwater velocity estimates between the INTEC and the 

assumed leading edge of the 3H plume in 1968. 

For several reasons, meaningful comparisons of the 

areal extent, shape, and dimensional features of the simulated 

particle plumes are limited to a comparison of the 3H plume 

that originated at the INTEC. The areal extent of the 3H plume 

downgradient of the RTC was much less extensive than that 

of the 1968 3H plume downgradient of the INTEC (fig. 41). 

The evolution of the RTC plume also was quite different from 

that of the INTEC plume. At the RTC all 3H was disposed of 

in the warm-waste ponds, about 450 ft above the water table. 
122 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Extensive perched water horizons were (and are) common 

beneath the RTC and the INTEC (Robertson and others, 1974, 

p. 95-101, 125-132) derived from Big Lost River infiltration, 

lateral flow in the unsaturated zone, and percolation of 

wastewater at the RTC infiltration ponds. As a result, the 

timing and location of 3H releases to the aquifer at the RTC 

from 1952 through 1968 are poorly defined. Furthermore, the 

first systematic mapping of 3H concentrations in the aquifer 

was in 1961 (Mann and Cecil, 1990, p. 17; Fromm and others, 

1994, p. 224). The analytical detection limit in use in 1961 

was 5,000 pCi/L. Maximum background concentrations 

of 3H from infiltration in the nearby Big Lost River would 

have been less than about 600 pCi/L2 (Busenberg and others, 

2001, p. 25, figs. 15, 16) from streamflow infiltration in 1958 

(fig. 43) (assuming no dilution with water in the aquifer). 

Concentrations of 3H above the analytical detection limit 

were reported after the first sampling round in all but one 

of the wells (USGS 84) downgradient of the RTC. The 

single downgradient well without a reportable detection 

likely contained facility-derived 3H that was less than the 

5,000 pCi/L analytical detection limit in 1961. Because of 

the sampling history of wells downgradient of the RTC and 

poor definition of the timing and release locations of 3H to 

the aquifer, useful first-arrival travel-time estimates and travel 

distances are not available to evaluate the results of the RTC 

particle-plume simulation.

Based on the depiction of Robertson and others 

(1974), the 1968 3H plume downgradient of the INTEC was 

exceptionally wide (6 mi) relative to its length (5 mi), with a 

ratio of 1.2 (fig. 41). The maximum linear velocity along the 

regional direction of groundwater flow that transported 3H to 

the leading edge of the plume, as defined by the 2,000 pCi/L 

isopleth in May 1968, was 4.7 ft/d, but may have been as 

much as 6.5 ft/d using the extended definition of the position 

of the leading edge in 1968 (10,000 ft south of the 2,000 pCi/L 

isopleth) previously described (table 25).

The north to south orientation and wide triangular 

shape of the 1968 plume may have resulted from variable 

streamflow infiltration from the Big Lost River. From 1953 

through 1964, streamflow in the Big Lost River was average 

to less than average and no diversions to the spreading areas 

took place (fig. 43A). During this period, 3H probably moved 

downgradient along the regional northeast to southwest flow 

direction. Above average streamflow in 1965 and 1967 and 

diversions to the spreading areas in 1965 resulted in a rise in 

the water table of 2–10 ft over a large area centered beneath 

the spreading areas, the Big Lost River channel, sinks, and 

playas and extending as much as 6 mi outward from these 

areas of rapid focused recharge (Robertson, 1974, fig. 9). 

This water-table rise would have changed the direction of 

the hydraulic gradient and caused shallow groundwater (and 

3H) between the Big Lost River and the RTC to move slower 

and in a more westerly direction, and shallow groundwater 

between the river and the INTEC to move faster and in a more 

easterly direction as illustrated in the wet-cycle and dry-cycle 

particle-tracking simulations (particles K, N and O; fig. 40; 

table 21).

Simulated Particle Plumes Downgradient of 

INTEC and RTC 

Particle plumes generated using the steady-state 

and transient flow models are shown in figure 45. The 

most noticeable differences between the steady-state and 

transient plumes are the (1) larger widths of transient plume 

segments, particularly downgradient of the boundary between 

hydrogeologic zones 11 and 1, compared to the equivalent 

steady-state plume segments; (2) slightly shorter travel 

distances of particles forming transient plume segments 

INTEC-D and RTC-G compared to the equivalent steady‐state

plume segments; and (3) westerly movement of particles 

from the INTEC disposal well (CPP 3) toward the RTC 

in the transient simulation that was not in the steady-state 

simulation. The larger widths of the transient plume segments 

and the westerly movement of particles from the INTEC 

towards the RTC were caused by variable wastewater disposal, 

groundwater withdrawal, and streamflow infiltration, which 

indicates that large-scale advective dispersion is greater 

under transient flow conditions than under steady-state flow 

conditions as illustrated in the steady-state and transient 

particle-tracking simulations (particles K, L, M, and N; fig. 38; 

table 20).

Plume Segment INTEC-A

Plume segment INTEC-A (fig. 45B) is composed of 

particles, released to model layer 1 at the INTEC disposal well 

and the INTEC disposal pit, 0.30 mi south of the disposal well, 

that traveled exclusively in hydrogeologic zone 11 (fig. 45B). 

The maximum distance the particles traveled downgradient 

in hydrogeologic zone 11 was 3.4 mi in 13.7 years, which 

corresponds to an average linear groundwater velocity of 

3.6 ft/d. This velocity is about 23 percent slower than the 

velocity represented by the leading edge of the 3H plume 

in 1968 and about 45 percent slower than the velocity 

represented by the extended definition of the leading edge 

(fig. 41; table 25). 

The wide distribution of particles and the north to south 

orientation of the plume segment were caused by (1) simulated 

radial flow in all directions from the cell where the particles 

originated, (2) transient effects of streamflow infiltration from 

1953 through 1968 (fig. 43), and (3) a gradient direction partly 

controlled by the large contrast in HC between hydrogeologic 

zones 1 and 11 (fig. 30). Radial flow away from the cell 

where the particles originated produced a wide distribution of 

particles. This wide distribution reflects the effects of the large 

fluxes of wastewater discharge at the INTEC disposal well. 

These fluxes represent more than 90 percent of the total flux 

passing through the model layer 1 cell at the INTEC disposal 

well.
Analysis of Advective Flow and Transport 123

Table 25. Groundwater and particle velocities based on the assumed position and extended definition of the leading edge of the tritium plume of 1968, transient particleplume and steady-state particle-pathline simulations, peak and first arrivals of tritium, tritium/helium-3 ages of the “young fraction” of groundwater, and first and peak arrivals of chlorine-36 at wells downgradient of the Idaho Nuclear Technology and Engineering Center and the Reactor Technology Complex, Idaho National Laboratory and vicinity, Idaho.[Tritium plume and downgradient wells for 1968 are shown in figure 41, simulated transient particle plume in figure 45B, and simulated steady-state pathline in figure 47. Distances measured from 

INTEC disposal well (CPP 3) or RTC warm-waste ponds. 3H/3He ages, Busenberg and others (2001); 36Cl arrivals, Cecil and others (2000). Abbreviations: INTEC, Idaho Nuclear Technology and 

Engineering Center; RTC, Reactor Technology Complex; 3H, tritium; 3He, helium-3; 36Cl, chlorine-36; vel, velocity; mi, mile; yrs, years; ft/d, foot per day; pCi/L, picocurie per liter]

Leading edge of 3H plume 

from May 1968

Transient particle-plume 

simulation

Steady-state particlepathline simulation 3H peak arrival or first arrival

Well 

3H/3He 

ages

36Cl arrivals

Velocity 

(ft/d) 

First Peak

Criteria Distance (mi) Time (yr) Velocity (ft/d) Plume segment Distance (mi) Time (yrs) Velocity (ft/d) Well Distance (mi) Time (yrs) Velocity (ft/d) Well Distance (mi) Time (yrs) Velocity (ft/d) Velocity (ft/d) Velocity (ft/d)

2,000 pCi/L 

isopleth 1

5.0 15.4 4.7 INTEC-A 3.4 13.7 3.6 USGS 36 0.95 1.8 7.6 USGS 36 0.95 1.0 214 USGS 103 4.3

Extended 

definition 3

6.9 15.4 6.5 INTEC-B 2.4 4.7 7.4 CFA 2 3.05 8.0 5.5 CFA 2 3.05 8.7 45.1 USGS 105 6.2

B-C 1.6 4.3 5.4 USGS 90 7.57 10.0 10.9 USGS 90 7.57 22.3 4.9

INTEC-C 3.8 9.1 6.0 USGS 108 8.33 10.5 11.5 USGS 103 7.95 30.6 3.8 USGS 109 6.2–7.2

C-D 19.7 6.9 41 USGS 105 8.86 10.5 12.2 USGS 108 8.33 30.8 3.9 USGS 124 7.5

A-E 10.4 2.3 65 USGS 105 8.86 30.8 4.2 USGS 125 10.2

A-F 14.1 3.3 62 USGS 11 12.5 515.9 8.4

INTEC-D 23.3 16.0 21.1 USGS 14 9.2 511.9 8.1

RTC-G 30.1 15.9 27.4

INTEC-USGS 11 14.9 11.0 19.6

RTC-USGS 11 15.1 14.5 15.1

INTEC-USGS 36 6 .95 13.7 1

INTEC-USGS 36 7 .95 1.5 9.2

1 Robertson (1974).2 Time series correlation of peak 3H concentrations at USGS 36 with monthly releases of 3H at CPP 3 - this report.3 Based on a comparison of the shape of the 3H concentration gradients used to define the leading edge of the 3H plumes of 1968 and 1985 - this report.4 Positive detection occurred with first sampling event following well construction. Reliability of first arrival time is questionable.5 USGS 11 36Cl concentration greater than 1.5 times background; USGS 14 36Cl concentration greater than 1.8 times background.

6 Model Layer 1.7 Model Layer 2.
124 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Figure 45. Particle plumes simulating the advective transport of tritium from the Idaho Nuclear Technology and Engineering Center 

and the Reactor Technology Complex for 16 years under (A) steady-state flow conditions in 1980 and (B) transient flow conditions from 

1953 through 1968, Idaho National Laboratory and vicinity, Idaho.

ID19-0164_GWflow_fig. 45A

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.

Big Lost River

spreading areas

A, B, C, and D

Big Lost River

INTEC disposal well (CPP 3) in well model layer 1

Starting location for particles

INTEC disposal well (CPP 3) in well model layer 2

INTEC seepage pit in model layer 1

RTC warm waste ponds in model layer 1

EXPLANATION

Hydrogeologic zones, model layer 1

Model area boundary

1—Younger rocks consisting of densely fractured basalt and sediment, with a 

sediment thickness of generally less than 11 percent of the stratigraphic section

2—Younger rocks consisting of massive, less densely fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent of the 

stratigraphic section

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent of the 

stratigraphic section

11—Younger rocks consisting of densely fractured basalt and sediment, with a 

sediment thickness of generally more than 11 percent of the stratigraphic section

22—Younger rocks consisting of massive, less densely fractured basalt and 

sediment, with a sediment thickness of generally more than 11 percent of the 

stratigraphic section

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

IDAHO

BOISE

EASTERN 

SNAKE RIVER

PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

RTC

INTEC

RWMC

CFA

113°20' 113°15' 113°10' 113°05' 112°55'

43°

35'

43°

20'

43°

25'

43°

30'

0 5 Miles

0 5 Kilometers

113°00'

Big Southern

Butte

A. Steady-state flow conditions, 1980
Analysis of Advective Flow and Transport 125

ID19-0164_GWflow_fig. 45B

Big Lost River

spreading areas

A, B, C, and D

Big Lost River

Starting location for particles

A, B, C

D, E, F, G

Indicates interim location of particles

Indicates the farthest point that particles moved downgradient

EXPLANATION

Hydrogeologic zones, model layer 1

Model area boundary

1—Younger rocks consisting of densely fractured basalt and sediment, with a 

sediment thickness of generally less than 11 percent of the stratigraphic section

2—Younger rocks consisting of massive, less densely fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent of the 

stratigraphic section

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent of the 

stratigraphic section

11—Younger rocks consisting of densely fractured basalt and sediment, with a 

sediment thickness of generally more than 11 percent of the stratigraphic section

22—Younger rocks consisting of massive, less densely fractured basalt and 

sediment, with a sediment thickness of generally more than 11 percent of the 

stratigraphic section

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

IDAHO

BOISE

EASTERN 

SNAKE RIVER

PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

INTEC disposal well (CPP 3) in well model layer 1

INTEC disposal well (CPP 3) in well model layer 2

INTEC seepage pit in model layer 1

RTC warm waste ponds in model layer 1

RTC

INTEC

RWMC

CFA

D

G

E

F

C A

B

113°20' 113°15' 113°10' 113°05' 112°55'

43°

35'

43°

20'

43°

25'

43°

30'

0 5 Miles

0 5 Kilometers

113°00'

Big Southern

Butte

USGS 11

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.

B. Transient flow conditions, 1953–68

Figure 45.—Continued.
126 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Plume Segment INTEC-B

Plume segment INTEC-B (fig. 45B) is composed of 

particles, released at the INTEC disposal well to model layer 

2 that traveled exclusively within hydrogeologic zone 22. The 

plume segment had a narrow trapezoidal shape, with width 

and length dimensions of about 0.8 and 2.8 mi, respectively. 

The particles at the leading edge of the plume segment 

traveled 2.4 mi downgradient in 4.7 years, which corresponds 

to an average linear groundwater velocity of 7.4 ft/d. This 

velocity is about 57 percent faster than the groundwater 

velocity based on the leading edge of the 1968 3H plume 

and about 14 percent faster than that based on the extended 

definition of the leading edge (fig. 41; table 25). 

The narrow distribution of particles and the northeast 

to southwest orientation of the plume segment were a result 

of releasing particles in model layer 2 to hydrogeologic zone 

22. Wastewater discharge in model layer 2 did not cause the 

simulation of radial flow in all directions from the particle 

origination cell because only about 18 percent of the total 

simulated wastewater injected through the INTEC disposal 

well was released to model layer 2 (table 24). Therefore, the 

contribution of wastewater to total flow through the cell is 

small compared to background flows. Additionally, streamflow 

infiltration was simulated as recharge to model layer 1 so it 

had minimal influence on flow directions in model layer 2.

Plume Segment B-C

Plume segment B-C (fig. 45B) is composed of particles, 

released at the INTEC disposal well to model layer 2 that 

traveled within hydrogeologic zone 11. The plume segment 

had a wide trapezoidal shape, with width and length 

dimensions of about 1.3 and 1.5 mi, respectively. The particles 

at the leading edge of the plume segment traveled 1.6 mi 

downgradient in 4.3 years, which corresponds to an average 

linear groundwater velocity of 5.4 ft/d. This velocity is about 

15 percent faster than the groundwater velocity based on 

the leading edge of the 1968 3H plume and about 17 percent 

slower than that based on the extended definition of the 

leading edge (fig. 41; table 25).

The directional deviation of the B-C plume segment 

and the relatively wider distribution of particles defined by 

the B-C plume segment compared to the INTEC-B segment 

resulted from groundwater flow refraction at the boundary 

of hydrogeologic zone 22, a medium with a large HC, and 

hydrogeologic zone 11, a medium with a smaller HC. Flow 

refraction across a boundary between media with different 

HC obeys a tangent law (Freeze and Cherry, 1979, p. 172) 

and is dependent on the HC ratio between the two media and 

the contact angle of flowlines intersecting at the boundary. 

In moving from a medium with a large HC to a medium 

with a smaller HC, flowlines will refract toward a line drawn 

perpendicular to the boundary. Refraction results in a change 

in the direction of flow and, in the case of flow from a medium 

of large HC to a medium of smaller HC, a widening of the 

width between flowlines intersecting at the boundary. 

Combining plume segments INTEC-B and B-C, the 

straight line distance from the INTEC disposal well to the 

boundary of hydrogeologic zone 1 and zone 11 (INTEC-C) is 

3.8 mi and the travel time is 9.1 years resulting in a composite 

velocity of 6.0 ft/d (table 25). This composite velocity is 

about 28 percent faster than the velocity based on the leading 

edge of the 1968 plume and about 8 percent slower than that 

based on the extended definition of the leading edge (fig. 41; 

table 25). The average linear groundwater velocity for the 

INTEC-C plume segment was faster than the INTEC-A plume 

segment, 3.6 ft/d, because the hydraulic gradient was steeper 

along the path of the B-C plume segment and the HC of the 

INTEC-B segment was much larger than that of the INTEC-A 

segment. 

Plume Segments C-D, A-E, A-F, and INTEC-D

Plume segment C-D (fig. 45B) is composed of particles, 

released at the INTEC disposal well to model layer 2 

that moved upward to model layer 1 at the boundary of 

hydrogeologic zones 1 and 11, and traveled primarily within 

hydrogeologic zone 1. Plume segment A-E is composed of 

particles released in model layer 1 at the INTEC disposal well, 

and plume segment A-F is composed of particles released in 

model layer 1 at the INTEC disposal pit. Plume segments A-E 

and A-F are entirely within model layer 1 and hydrogeologic 

zone 1. The northeast to southwest orientation of these plume 

segments is similar to the regional direction of groundwater 

flow. The particles at the leading edge of these plume 

segments traveled 19.7 mi in 6.9 years, 10.4 mi in 2.3 years, 

and 14.1 mi in 3.3 years, which correspond to average linear 

groundwater velocities of 41, 65, and 62 ft/d for plume 

segments C-D, A-E, and A-F, respectively. These velocities are 

about 1 order of magnitude faster than groundwater velocities 

based on the leading edge of the 1968 3H plume and on the 

extended definition of the leading edge (fig. 41; table 25).

Plume segments C-D, A-E, and A-F are long and 

narrow. The widths of these plumes are initially controlled 

by groundwater flow refraction across the boundary of 

hydrogeologic zone 1 and zone 11. At this boundary, flow is 

from a medium with a small HC to a medium with a higher 

HC and flowlines intersecting this boundary refract away from 

a line drawn perpendicular to the boundary. Flow refraction in 

this case results in a narrowing of the width between flowlines. 

Farther downgradient the widths of these plume segments 

gradually increase in response to the dispersive effects of 

streamflow infiltration under transient flow conditions as was 

described in the steady-state/transient and wet-cycle/dry-cycle 

particle-tracking simulations.
Analysis of Advective Flow and Transport 127

From the INTEC disposal well to the end of plume 

segment C-D (INTEC-D) particles released in model layer 2 

traveled a distance of 23.3 mi in 16.0 years, which corresponds 

to an average linear groundwater velocity of 21.1 ft/d. From 

the INTEC disposal well to USGS 11 the particles traveled 

a distance of 14.9 mi in 11.0 years, which corresponds to 

an average linear groundwater velocity of 19.6 ft/d, about 

23 percent faster than the velocity estimate for the assumed 

first arrival of 36Cl at USGS 11, 16 ft/d (fig. 41; table 25).

Simulated velocities for particles released at the INTEC 

disposal well and disposal pit indicate that the velocity of 

particles composing plume segment INTEC-D (21 ft/d) 

represents the composite velocity from flow through three 

velocity zones: (1) a slow-velocity zone (1.0–9.2 ft/d) 

represented by hydrogeologic zones 11 and 22, with a gradient 

of about 3 ft/mi, a HC of 227–4,780 ft/d, and an effective 

porosity of 0.07–0.15; (2) a fast-velocity zone (62–65 ft/d) 

represented by hydrogeologic zone 1, with a gradient of about 

3 ft/mi, a HC of 11,700 ft/d, and an effective porosity of 0.07; 

and (3) a medium-velocity zone (20–22 ft/d) represented by 

hydrogeologic zones 2 and 3, with a gradient of about 

20 ft/mi, a HC of 384–435 ft/d, and an effective porosity of 

0.03–0.14 (tables 14, 19, and 24). VANI for all three zones is 

14,800 (table 14).

Plume Segments INTEC-A, INTEC-B, and B-C Combined

Particle movement within the upper 200 ft of the 

aquifer is represented by the assimilation of plume segments 

INTEC-A, INTEC-B, and B-C into a single composite plume 

(fig. 45B). This combined plume represents particles released 

at the INTEC to model layers 1 and 2 that traveled through 

hydrogeologic zones 11 and 22. The shape of the combined 

plume was elliptical, with a width (2.8 mi) to length (4.0 mi) 

ratio of 0.70 (fig. 45B). The combined plume, although larger, 

most closely resembles the shape and aspect ratio of the 3H 

plume defined by the 1968 25,000 pCi/L isopleth (fig. 41). 

The 25,000 pCi/L isopleth encloses a plume area with a 

width (2.0 mi) to length (3.2 mi) ratio of 0.62. The long axis 

of the combined plume is oriented north-northeast to southsouthwest, an orientation that is slightly different from the 

north to south orientation of the 3H plume represented by the 

25,000 pCi/L isopleth. 

The distance downgradient from the INTEC that 

particle plumes were able to reasonably reproduce the 1968 

3H plume extended only to the boundary of hydrogeologic 

zones 1 and 11 (fig. 45B). This boundary encompasses the 

entire area represented by the 1968 25,000 pCi/L isopleth 

(fig. 41). Particle plumes simulated beyond this boundary 

were long and narrow, and did not reasonably reproduce the 

shape, dimensions, or position of the 3H plume as depicted 

by Robertson and others (1974); however as noted previously 

not enough data are available to characterize the true areal 

extent and shape of the 1968 3H plume. The long, narrow 

shape of the simulated particle plumes downgradient of the 

hydrogeologic zone 1-zone 11 boundary was caused by the 

large HC of zone 1 and groundwater flow refraction at the 

boundary of zone 1 and zone 11.

Plume Segment RTC-G

The plume segment RTC-G is composed of particles 

released at the RTC warm-waste ponds to model layer 1 that 

traveled within hydrogeologic zones 22, 1, 2, and 3 (fig. 45B). 

Initially the particles traveled west and south along the edge 

of the hydrogeologic zone 1-zone 11 boundary, and then 

traveled northeast to southwest along the regional direction of 

groundwater flow. The resulting plume segment was long and 

narrow, with length and width dimensions of about 30.1 and 

2.0 mi (fig. 45B), respectively. The orientation of the plume 

segment varied geographically, but the overall orientation, 

northeast to southwest, was similar to the regional direction 

of groundwater flow. The particles at the leading edge of the 

plume segment traveled 30.1 mi downgradient in 15.9 years, 

which corresponds to an average linear groundwater velocity 

of 27.4 ft/d.

The long length of plume segment RTC-G was caused 

by the particles traveling mostly through hydrogeologic zone 

1, which has a large HC. This large HC produced an average 

linear groundwater velocity of 27.4 ft/d, which was 5.8 times 

faster than the velocity based on the leading edge of the 1968 

3H plume and 4.2 times faster than the velocity based on the 

extended definition of the leading edge.

Simulated particles released at the RTC initially traveled 

west and south to areas outside of the 1968 3H plume and 

to areas where INL-derived 3H has not been historically 

observed. Few monitoring wells are southwest of the RTC, 

resulting in poor definition of where 3H released from the RTC 

may reside in the aquifer. However, sampling of monitoring 

well Middle 2051 (table A1; figs. B1, B2), a well equipped 

with five packer-isolated water-sampling ports about 3 mi 

southwest of the RTC, in September 2005 and May-June 

2006, found 3H concentrations ranging from 428 to 745 

pCi/L at depths of 179, 257, 521, and 571 ft below the water 

table (table 26). These concentrations and the RTC-G plume 

segment indicate that 3H released at the RTC may reside in the 

aquifer southwest of the RTC. 

Simulated Particle Velocities Compared to 

Velocities Based on Peak and First Arrivals of 

Tritium 

To avoid some ambiguity and uncertainty associated 

with the assumed position of the leading edge of the 1968 

3H plume and the extended definition of its position, 

model‐derived average linear groundwater velocities also

were compared to the peak and first arrival times of 3H at five 
128 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

wells downgradient of the INTEC disposal well (CPP 3) that 

have had at least one 3H detection exceeding the analytical 

detection limit. Travel time estimates are based on (1) a 

time‐series correlation of semi-annual 3H concentrations at

USGS 36 with semi-annual 3H releases at the INTEC disposal 

well (fig. 46) herein referred to as peak arrival-time estimates; 

(2) the assumed first arrivals of 3H at CFA 2, USGS 90, USGS 

105, and USGS 108 (fig. 47); and (3) a steady-state simulation 

of the time required for a particle originating at the INTEC 

disposal well to arrive at or near these five monitoring wells 

(fig. 47). Monitoring wells USGS 36, CFA 2, USGS 90, 

USGS 105, and USGS 108 extend about 90, 210, 50, 130, and 

150 ft below the water table, and are about 1.06, 2.89, 7.10, 

8.97, and 8.56 mi downgradient of the INTEC disposal well, 

respectively (fig. 46). 

The travel time between the INTEC disposal well and 

USGS 36 was estimated by correlating the monthly activity 

of 3H discharged at the disposal well with the semi-annual 

concentrations of 3H in water from USGS 36 (fig. 46). A 

352 day travel time for 3H traveling between the INTEC 

disposal well and USGS 36 produces the optimal time-lagged 

correlation for this analysis (Pearson correlation coefficient [r] 

= 0.72, samples [n] = 44). The 352-day travel time correlates 

with the 3H concentrations at USGS 36 from January 1966 to 

November 1988 with the monthly activity of 3H discharged 

at the INTEC from January 1965 to December 1987. The 

resulting average linear groundwater velocity was about 

14 ft/d. Uncertainty in the correlation resulted from using 

semi-annual 3H concentrations at USGS 36 and monthly 

estimates of 3H discharged at the INTEC disposal well and 

assuming that 3H concentrations at USGS 36 were derived 

solely from the INTEC disposal well.

The assumed first arrival times of INTEC-derived 3H 

at CFA 2, USGS 90, USGS 105, and USGS 108 correspond 

to the first detections of 3H in groundwater from these wells. 

Table 26. Tritium concentrations in water collected from well Middle 2051, Idaho National Laboratory, Idaho.

[Analytical results and uncertainties—for example 68 ± 116—in picocuries per liter. Analytical results are reported to 1s. 

Concentrations that equal or exceed the reporting level of 3s are shown in bold. Data are from Renee Bowser, CWI, written commun., 

2007, and http://nwis.waterdata.usgs.gov/nwis/, accessed March 6, 2007. Abbreviations: CWI, CH2M-WG Idaho LLC; USGS, U.S. 

Geological Survey; pCi/L, picocuries per liter; ft, foot]

Approximate 

depth below 

water table (ft)

Corresponding 

flow model layer

Tritium concentration (pCi/L)

September 2005 (CWI) September 2005 (USGS) May–June 2006 (CWI)

33 1 68 ± 116 -60 ± 100 7.7 ± 112

179 2 632 ± 136 680 ± 130 449 ± 123

257 3 745 ± 141 670 ± 130 1571 ± 127

521 5 123 ± 116 240 ± 110 428 ± 125

571 5 172 ± 120 -70 ± 100 587 ± 123

1

 Mean of sample + replicate.

These arrival times are assumed because (1) 3H may have 

reached these wells at earlier times at concentrations below 

the analytical detection limit and (2) 3H was detected in the 

first water samples collected from CFA 2 at relatively high 

concentrations, suggesting that 3H likely reached CFA 2 

much earlier than the time of its first detection. The routine 

analytical detection limit for 3H in use at the time of these 

first-arrival detections was 2,000 pCi/L for the CFA 2 and 

USGS 90 detections, and 500 pCi/L for the USGS 105 and 

108 detections (Mann and Cecil, 1990, p. 20 and 22). 

The assumed first arrival times at CFA 2 (August 1961; 

14,000 pCi/L), USGS 90 (April 1975; 1,200 pCi/L), USGS 

105 (October/November 1983; 3,400 pCi/L), and USGS 108 

(October/November 1983; 830 to 3,400 pCi/L) (Mann and 

Cecil, 1990, p. 22, 25, and 29) were 8.7, 22.3, and 30.8 years, 

respectively, after 3H was initially discharged at the INTEC 

disposal well in January 1953. These assumed first arrival 

times resulted in average linear groundwater velocities of 3.9 

to 5.1 ft/d (table 25).

Travel times of 3H and average linear velocities were 

simulated by releasing a single particle, under steady-state 

flow conditions, at the center of the model layer 2 cell in 

hydrogeologic zone 22 at the INTEC disposal well. Travel 

time estimates based on this simulation scenario represent 

minimum travel times and maximum velocities because 

the HC of hydrogeologic zone 22 is more than one order 

of magnitude larger than the HC of hydrogeologic zone 11 

(table 14) in model layer 1. Average linear particle velocities 

simulated under steady-state flow conditions are faster than 

velocities under transient flow conditions because particle 

movement is not affected by temporal changes in the local 

hydraulic gradient and pathline divergence (figs. 38, 40, 45; 

tables 20, 21). The resulting particle path, plotted as a pathline, 

is shown in figure 47.
Analysis of Advective Flow and Transport 129

ID19-0164_GWflow_fig. 46 1964 1965 1966 1967 1968

19691970197119721973197419751976197719781979198019811982198319841985198619871988

20

40

Year

60

80

100

Tritium concentration at USGS 36, in picocuries per milliliter

4,174 INTEC disposal well (CPP 3) and pit

INTEC infiltration ponds

USGS 36, time shifted 352 days for 

time-lagged correlation, r = 0.72, 

n = 44

0

500

1,000

1,500

2,000

2,500

2,700

Tritium concentration, in picocuries per milliliter

Figure 46. Concentrations of tritium in wastewater discharged at the Idaho Nuclear Technology and Engineering 

Center from 1964 through 1988 and concentrations of tritium in water from monitoring well USGS 36 from 1966 

through 1988, Idaho National Laboratory, Idaho. 

The simulated travel times of a particle released at the 

location of the INTEC disposal well to reach USGS 36, CFA 

2, USGS 90, USGS 105, and USGS 108 (fig. 47) were 1.8, 8.0, 

10.0, 10.5, and 10.5 years resulting in average linear velocities 

of about 7.6, 5.5, 10.9, 12.2, and 11.5 ft/d, respectively 

(table 25). For wells outside the particle pathline (for example, 

CFA 2, USGS 90, USGS 105, and USGS 108) travel times 

were estimated using the time required for a particle to reach 

a location within closest proximity to a well. Because wells 

USGS 36 and USGS 90 penetrate only model layer 1, using 

travel times to these wells for particles released in modellayer 2 may not be valid. Simulation of the particle travel time 

between the disposal well and USGS 36, for a particle released 

in model layer 1, resulted in a travel time of 3.6 years and 

a velocity of 4.6 ft/d, or one-half the velocity of the particle 

released in model layer 2. However, the particle traveled south 

and not southwest towards USGS 36. For particles released 

in model layers 1 and 2, the range of travel times between the 
130 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Figure 47. Pathline and cumulative travel times for a particle simulating steady-state groundwater flow from the Idaho Nuclear 

Technology and Engineering Center disposal well (CPP 3) to the southern boundary of the Idaho National Laboratory used to 

evaluate model-derived travel times to selected wells, Idaho National Laboratory and vicinity, Idaho.

ID19-0164_GWflow_fig. 47

Big Lost River

spreading areas

A, B, C, and D

Big Lost River

EXPLANATION

Hydrogeologic zones, model layer 1

Model area boundary

1—Younger rocks consisting of densely fractured basalt and sediment, with a 

sediment thickness of generally less than 11 percent of the stratigraphic section

2—Younger rocks consisting of massive, less densely fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent of the 

stratigraphic section

3—Intermediate-age rocks consisting of slightly altered fractured basalt and 

sediment, with a sediment thickness of generally less than 11 percent of the 

stratigraphic section

11—Younger rocks consisting of densely fractured basalt and sediment, with a 

sediment thickness of generally more than 11 percent of the stratigraphic section

22—Younger rocks consisting of massive, less densely fractured basalt and 

sediment, with a sediment thickness of generally more than 11 percent of the 

stratigraphic section

Site facilities

Idaho National Laboratory boundary

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

RTC—Reactor Technology Complex

RWMC—Radioactive Waste Management Complex

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

RTC

INTEC

RWMC

CFA

113°20' 113°15' 113°10' 113°05' 112°55'

43°

35'

43°

20'

43°

25'

43°

30'

0 5 Miles

0 5 Kilometers

113°00'

Big Southern

Butte

USGS 36

USGS 90

USGS 108

USGS 105 USGS 103

CFA 2

8

1.75

10

10.5

Pathline and cumulative travel time,

in years

USGS 108

8

1.75

10

10.5

Well and well name

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.

CPP 3
Summary and Conclusions 131

disposal well and USGS 36 was 1.8–3.6 years, resulting in a 

range of average linear velocities of 4.6–9.2 ft/d. The travel 

time between the disposal well and USGS 90 for the particle 

released in model layer 2 is valid because the particle moved 

upward to model layer 1 before reaching the vicinity of USGS 

90. The particle paths intersected or nearly intersected USGS 

36 (layer 2 particle) and USGS 105, but did not intersect CFA 

2, USGS 90, or USGS 108 (fig. 47). The large differences in 

calculated (16 to 33 ft/d) and simulated (4.6–9.2 ft/d) average 

linear groundwater velocities between the INTEC disposal 

well and USGS 36 may result from the injection of wastewater 

into the aquifer at the disposal well. The influence of 

wastewater injection on contaminant velocities was observed 

by Jones (1963, p. 228) who noted that wastewater discharge 

increased contaminant velocities by a factor of 2 to 4 between 

the contaminant injection point and a monitoring well 

approximately 1,000 ft downgradient. The rate of wastewater 

discharged from the disposal well during the correlation period 

of 1966–83 was 1.8 ft3/s, or about 28 percent more than the 

1.4 ft3/s simulated with the steady-state flow model. 

Comparison of 3H velocities and simulated average linear 

particle velocities between the disposal well and CFA 2, USGS 

90, USGS 105, and USGS 108 provided an indication of the 

quality of the model. The velocities for 3H and the particle 

between the disposal well and CFA 2 were similar (table 25), 

which indicates that the model may be fairly representative. 

In contrast, the simulated velocity of the particle between the 

INTEC disposal well and wells USGS 90 (11 ft/d), USGS 105 

(12 ft/d), and USGS 108 (11 ft/d) was about 2 to 3 times faster 

than the velocity calculated from the assumed first arrival of 

3H at these wells (table 25).

Summary and Conclusions

Three-dimensional (3-D) steady-state and transient 

models of groundwater flow and advective transport in the 

eastern Snake River Plain (ESRP) aquifer were developed by 

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

U.S. Department of Energy (DOE) to better understand the 

aquifer system and the movement of wastes in the aquifer. 

A 50-plus year history of waste disposal associated with 

nuclear-reactor research and nuclear-fuel reprocessing at the 

Idaho National Laboratory (INL) has resulted in measurable 

concentrations of contaminants in the ESRP aquifer beneath 

the INL. The model area, in the west-central part of the ESRP, 

is 1,940 mi2, extends 35 mi from northwest to southeast 

and 75 mi from northeast to southwest, and includes most 

of the INL (890 mi2). Model simulation results can be 

used in numerical simulations to evaluate the movement of 

contaminants in the ESRP aquifer at the INL.

Saturated flow in the ESRP aquifer was simulated 

using the USGS modular, finite-difference groundwater flow 

model MODFLOW–2000. Steady-state flow was simulated 

to represent conditions of 1980 with average streamflow 

infiltration from 1966–80 for the Big Lost River, the major 

variable inflow to the system. The transient flow model 

simulates groundwater flow between 1980 and 1995, a 

period that included a 5-year wet cycle (1982–86) followed 

by an 8-year dry cycle (1987–94). The years 1983–84 and 

1987–94 produced the maximum streamflow and the longest 

dry period, respectively, in the Big Lost River over the past 

60 years. Particle-tracking computations using the USGS 

particle-tracking program MODPATH and various graphics 

programs were used to simulate advective transport with 

the flow models and produce 2-D maps of 3-D flow in the 

aquifer and to evaluate how (1) simulated groundwater flow 

paths and travel times vary between the steady-state and 

transient flow models, (2) wet- and dry-climate cycles affect 

groundwater flow paths and travel times, and (3) modelderived groundwater flow directions and velocities compare 

to independently derived estimates in that part of the aquifer 

most affected by contamination. 

The fractured basalts, interflow zones, rhyolitic rock 

units, and interbedded sediments of the ESRP aquifer are 

represented as porous media and are grouped into four primary 

hydrogeologic units. In areas where sediment constitutes more 

than 11 percent of the stratigraphic section, hydrogeologic 

units are further subdivided to distinguish sediment-rich areas 

from sediment-poor areas. The four primary hydrogeologic 

units were subdivided into eight hydrogeologic zones based on 

sediment abundance. A ninth hydrogeologic zone represents 

rhyolitic rocks. Model parameters estimated for the steadystate calibration represented horizontal hydraulic conductivity 

(HC) for seven of nine hydrogeologic zones and a global value 

of the vertical anisotropy (VANI)—the ratio of horizontal 

to vertical hydraulic conductivity. In this representation of 

the aquifer, the small-scale heterogeneities and anisotropies 

of individual basalt flows, basalt flow groups, rhyolites, and 

interbedded sediments are not preserved, and the resulting HC 

of the hydrogeologic zones reflects the aggregate lithology, 

thickness, and number of basalt flows, interflow zones, and 

sedimentary interbeds in each hydrogeologic zone.

Three physical and three artificial boundaries define the 

model area. The physical boundaries are the water table, the 

northwest mountain-front, and the base of the aquifer. The 

artificial boundaries are the northeast regional-underflow, the 

southeast flowline, and the southwest regional-underflow. 

Inflow to the aquifer is across the water table, northwest 

mountain-front, and northeast regional-underflow boundaries; 

outflow is to wells and the southwest regional-underflow 

boundaries. The base of the aquifer and the southeast flowline 

boundary are treated as no-flow boundaries. In the steadystate model, flow across inflow and outflow boundaries is 

represented as temporally constant with spatially uniform 

and nonuniform flow distributions. Streamflow infiltration 

from the Big Lost River channel, spreading areas, sinks, and 

playas represent the largest transient stress. The volume of 

groundwater flow in the aquifer increases progressively in 

a direction downgradient of the northeast boundary. Most 

increased flow is the result of the addition of underflow 
132 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

from the tributary-valleys of the Big Lost River, Little Lost 

River, and Birch Creek and streamflow infiltration across 

the water‐table boundary, primarily from the Big Lost River.

Together these additions account for about 40 percent of the 

outflow across the southwest boundary; the remaining outflow 

is from regional aquifer underflow across the northeast 

boundary. Specified flows into or out of the active model grid 

define the conditions on all boundaries except the southwest 

(outflow) boundary, which is simulated with head-dependent 

flow. Time was discretized in the transient model as 1 year 

of steady-state conditions (1980) followed by 15 years 

with 4-month stress periods to represent seasonal cycles of 

streamflow infiltration, industrial withdrawal and returns, and 

irrigation withdrawal and infiltration. 

Calibration of the models used parameter-estimation 

techniques incorporated in MODFLOW-2000 that uses 

the nonlinear least-squares regression method. Calibration 

data consisted of 201 head observations for steady state. 

Transient calibration data consisted of 328 head and 8,171 

head-difference observations. In the calibration process, 

models were evaluated by visual and statistical comparisons 

of estimated parameter values to expected values, the fit of 

simulated to observed heads or head differences, and the 

statistical reliability of parameter estimations. The same types 

of statistical measures, graphs, and maps were used to evaluate 

the alternative models with changes in system geometry, 

boundary conditions, and parameters. 

Estimates of HC ranged from 227 to 11,700 ft/d, and the 

estimated value of VANI was 14,800. All estimates of HC 

were nearly within 2 orders of magnitude of the maximum 

expected value in a range that exceeds 6 orders of magnitude. 

The estimated values are more consistent with the greater 

expected values of HC parameters derived from large-scale 

aquifer tests than with lesser values derived from small-scale 

aquifer tests or laboratory tests on core samples. Vertical 

anisotropy of the model domain was greater than the highest 

value of a few aquifer tests of short aquifer intervals, but only 

slightly greater than an independent estimate based on the 

contrasts in hydraulic conductivity of basalts and interbedded 

sediment. Parameter reliability, as measured by the confidence 

interval size and its relation to the expected range of values, 

was least for two HC parameters and VANI, which were least 

constrained by observations. 

The steady-state model reasonably simulated the 

observed water-table altitude, orientation, and gradients. 

Simulation of observed vertical flow directions and gradients 

was best for greater vertical gradients. Simulation of heads 

near the water table was better than for heads representing 

multiple open intervals below the water table or from deeper 

parts of the aquifer, although weighted residuals were 

distributed evenly about zero. The collection of additional 

head data at multiple levels in the aquifer may improve the 

estimates of aquifer properties and the simulations of heads 

at depth and vertical flow. Recent geostatistical modeling of 

sediment abundance in the upper 300 ft of the aquifer in the 

study area suggests a better spatial resolution for delineating 

relative sediment abundance within the model layers and 

aquifer parameter zones. This information may provide a 

parameterization with more spatial resolution of HC within 

zones of abundant sediment.

Recalibration and analysis of the steady-state 

model to changes in aspects of the conceptual model and 

implementation of the numerical model revealed that little 

improvement in the model could come from the tested 

alternate conceptualizations of sediment content, aquifer 

thickness, streamflow infiltration, or changes in vertical head 

distribution on the downgradient boundary. Of the tested 

alternative estimates of flow to or from the aquifer, only a 

20 percent decrease in the largest flow, the northeast boundary 

underflow, resulted in a recalibrated parameter value just 

outside the confidence interval of the base-case calibrated 

value. Features of the flow system, such as the dominance 

of horizontal flow or downward flow downgradient of the 

INL, were not affected. Other recalibrations did not improve 

calibration or result in significant changes to estimated 

parameter values. 

Model parameters estimated for the transient calibration 

represented specific yield (SY) for five of the seven 

hydrogeologic zones present at the water table. Estimates 

of SY ranged from 0.029 to 0.116. All estimates of SY and 

their confidence intervals were within the ranges of values 

expected for the parameters and the range of porosity of 

basalt. Confidence intervals for two of the parameters were 2 

to 3 times larger than confidence intervals of other parameters. 

The confidence intervals probably were larger because fewer 

observations constrained the estimated values and because 

of the increased distance of the corresponding hydrogeologic 

zones from the Big Lost River, the locus of change in 

water levels. Simulation of transient conditions accurately 

represented changes in the flow system resulting from 

episodic infiltration from the Big Lost River and facilitated 

understanding and visualization of the relative importance 

of differences in infiltration flux due to (1) extended periods 

of flow and drought, (2) differences in infiltration rates, and 

(3) changes in diversions. Simulation of transient conditions 

could not reproduce annual fluctuations of water levels in 

the northeast quarter of the model where seasonal irrigation 

pumpage occurs. The quality of the simulated water-level 

change is good, however, in the other parts of the model 

where more information is available and that coincide with the 

area of greatest interest near observed contamination of the 

aquifer. Recalibration and analysis of the transient model to 

changes in boundary conditions revealed little improvement 

in the simulation of alternate conceptualizations of annual 

fluctuations of inflow in the northeast quarter of the model 

area. 

As described in the conceptual model, the numerical 

models simulate flow that is (1) dominantly horizontal through 

interflow zones in basalt and vertical anisotropy resulting 

from contrasts in hydraulic conductivity of various types of 

basalt and the interbedded sediments, (2) temporally variable 

due to streamflow infiltration from the Big Lost River, and 

(3) moving downward downgradient of the INL.
Summary and Conclusions 133

Single-particle tracking simulations were used to evaluate 

the effect of transient stresses on groundwater flowpaths 

and velocities. Ten-year steady-state particle pathlines were 

compared to 10-year transient pathlines that included the last 

4 years of a wet-climate cycle from 1983 through 1986 and 

the first 6 years of a dry-climate cycle from 1987 through 

1992. Particle tracking also was used to compare the effects 

of streamflow infiltration from the Big Lost River channel, 

spreading areas, sinks, and playas during a wet-climate cycle 

to the effects of no recharge from these sources during a 

dry‐climate cycle

Collectively, these particle-tracking simulations 

indicate that average linear groundwater velocities, based 

on uncalibrated estimates of porosity, and flow paths are 

influenced by two primary factors: (1) the dynamic character 

of the water table and (2) the large contrasts in the hydraulic 

properties of the media, primarily hydraulic conductivity. 

The simulated growth and decay of large groundwater 

mounds as much as 34 ft above the steady-state water table 

beneath the Big Lost River spreading areas, sinks, and 

playas, and to a lesser extent beneath the Big Lost River 

channel lead to nonuniform changes in the altitude of the 

water table throughout the model area. These changes affect 

the orientation and magnitude of water-table gradients and 

groundwater flow directions and velocities to a greater or 

lesser degree depending on the magnitude, duration, and 

proximity of the transient stress. In areas that are in close 

proximity to streamflow infiltration, simulation results indicate 

that pathline divergence, caused by climate-induced temporal 

changes in the local hydraulic gradient, can account for some 

of the observed dispersion of contaminants in the aquifer 

near the Idaho Nuclear Technology and Engineering Center 

(INTEC) and the Reactor Technology Complex (RTC) and 

perhaps most observed dispersion several miles downgradient 

of these facilities.

Multiple-particle tracking simulations were used to 

simulate the growth of tritium (3H) plumes at the INTEC and 

RTC under steady-state conditions for 16 years and under 

transient conditions from 1953 to 1968. In the transient 

simulation, initial conditions were defined by the steady-state 

model and transient stresses were based on annual, and when 

available, semi-annual estimates of groundwater withdrawals, 

wastewater disposal, and streamflow infiltration from 1953 

through 1968 allocated over 4-month simulation periods.

The 2-D shape, dimensions, and areal extent of these 

particle plumes were compared to maps of the 3H plumes in 

the aquifer in 1968 that originated from 3H releases at the 

INTEC and RTC beginning in 1952. Model-derived average 

linear groundwater velocities were compared to velocity 

estimates based on (1) the position of the assumed leading 

edge of the 3H plume in 1968, (2) an extended definition of 

the leading edge based on a comparison of the shape of the 

3H concentration gradients used to define the position of the 

leading edge of the 3H plumes in 1968 and 1985, and (3) the 

assumed first arrival of 3H and chlorine-36 (36Cl) and the 

tritium/helium-3 ages of the young fraction of groundwater in 

wells downgradient of the INTEC and the RTC. 

Results of these multiple-particle simulations indicate 

that the velocity of particles defining the leading edge of the 

simulated plume originating at the INTEC represents the 

composite velocity of flow through three velocity zones: (1) a 

slow-velocity zone, 1.0–9.2 ft/d, represented by hydrogeologic 

zones 11 and 22, zones of abundant sediment, with a hydraulic 

gradient of about 3 ft/mi, a HC of 227–4,780 ft/d, and an 

effective porosity of 0.07–0.15 ft/d; (2) a fast-velocity zone, 

62–65 ft/d, represented by hydrogeologic zone 1, with a 

gradient of about 3 ft/mi, a HC of 11,700 ft/d, and an effective 

porosity of 0.07; and (3) a medium-velocity zone, 20–22 ft/d, 

represented by hydrogeologic zones 2 and 3, with a gradient of 

about 20 ft/mi, a HC of 384–435 ft/d, and an effective porosity 

of 0.03–0.14. Model-derived velocities compare favorably 

with independently derived velocity estimates within areas of 

abundant sediment, hydrogeologic zones 11 and 22. Except 

for the assumed first-arrival velocity of 36Cl at USGS 11 and 

USGS 14, model-derived velocities were much faster than 

independent velocity estimates such as those based on the 

assumed first arrival of 3H or the tritium/helium-3 ages of the 

young fraction of groundwater at wells downgradient of the 

boundary of hydrogeologic zones with abundant sediment. 

The reliability of velocity estimates based on the assumed 

first arrival time of 3H, however, is questionable because of 

sampling frequency and limitations in the analytical detection 

limit used to distinguish background 3H concentrations from 

facility-derived 3H concentrations. The simulated composite 

velocity of 20 ft/d for particles released at the INTEC disposal 

well (CPP 3) and measured at USGS 11, a distance of 14.9 mi, 

compares favorably with an independent velocity estimate of 

16 ft/d for the assumed first-arrival of 36Cl at USGS 11. 

The distance downgradient of the INTEC that simulated 

particle plumes were able to reproduce the shape and 

dimensions reasonably of the 1968 3H plume extended to 

the boundary of areas of abundant sediment, hydrogeologic 

zones 22 and 11, a distance of about 4 mi. This boundary 

encompasses the entire area represented by the 1968 

25,000 picocuries/liter (pCi/L) isopleth. The shape of the 

simulated particle plume was elliptical with a width (2.8 mi) 

to length (4.0 mi) ratio of 0.70, a ratio that approximates 

the 0.62 width (2.0 mi) to length (3.2 mi) ratio of the 1968 

plume defined by the 25,000 pCi/L isopleth. Particle plumes 

simulated beyond this boundary were narrow and long, 

and did not reasonably reproduce the shape, dimensions, or 

position of the leading edge of the 3H plume as depicted in 

earlier reports; however, as noted in an assessment of the 1968 

plume, few data were available to characterize its true areal 

extent and shape. 
134 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Although the numerical models described in this report 

are intended to provide a large-scale representation of a 

complex flow system that includes the integrated effects of 

many small-scale features and interactions, several apparent 

shortcomings are worth noting: 

1. The optimized HC for hydrogeologic zone 22 in the 

area of abundant sediment is larger than that of zone 

2 in the area of little or no sediment. This result is 

inconsistent with current conceptual interpretations of the 

hydrogeologic properties of hydrogeologic units affected 

by the presence of abundant sediment. 

2. Simulated vertical head gradients in the first 600–500 ft 

at two wells, USGS 103 (near the southern boundary of 

the INL), and USGS 132 (south of the RWMC) are 0.1 

(downward) as compared to approximately 0.001 upward 

or downward when compared to recent multi-level 

piezometric heads. The difference may reflect error in 

the specified positions of hydrogeologic-zone boundaries 

or insufficient depth-dependent head data to calibrate 

parameter values.

3. The single optimized value of VANI is an order of 

magnitude larger than local measured values, but is 

similar to other estimated values. The local variation 

of VANI may be present but not supported by the 

distribution of head at depth within the aquifer in the 

calibration data set.

4. The simulated vertical movement of contaminants in the 

south of the INL as indicated by particle tracking may 

not be as deep as suggested by recent detection of 3H in 

multi-level piezometers near the south boundary. These 

3H detections, if confirmed, are a few hundred feet deeper 

in the aquifer than indicated by the INTEC and RTC 

particle-tracking simulations presented in this report. This 

is a tentative conclusion that may be related to causes 

similar to the larger simulated vertical head gradients. 

5. Model-derived average linear groundwater velocities 

within hydrogeologic zone 1 are generally faster than 

independently derived estimates; however, the reliability 

of these independent estimates also is subject to 

considerable uncertainty.

These apparent shortcomings indicate a need for further 

study and refinement of the existing models. Several of 

these shortcomings, particularly (2), (3), and (4) suggest 

that additional observations of head at depth would support 

estimation of additional parameters and improve calibration. 

Recalibration of the existing models using recently acquired 

vertical head data and their error estimates from eight 

instrumented wells in the southwestern part of the INL, 

the part of the aquifer most affected by contamination, 

may be able to substantiate and resolve some of the noted 

shortcomings. These wells are instrumented to measure 

pressure heads and temperature, and sample aquifer water in 

isolated intervals down to depths of about 300 (model layer 

3) to 800 ft (model layer 5) below the water table. Repeated 

measurements since 2007 indicate that vertical head gradients 

are generally stable as to direction and fluctuate within a 

relatively small range. Additional improvement of model 

calibration and finer resolution of the aquifer parameter values 

in the area of abundant sediment also may be possible by 

incorporating geostatistical estimates of sediment abundance.

The numerical models described in this report provide a 

large-scale integrated framework within which to incorporate 

smaller-scale contaminant transport models. Hydrogeologic 

zones used to represent the aquifer in the present models 

are assumed to be adequately represented as homogeneous, 

anisotropic porous media; small-scale heterogeneity within 

individual hydrogeologic zones is not represented. Because 

of this limitation, the particle plume simulations do not 

incorporate the effects of small-scale tortuosity and likely 

underestimate the full extent of dispersion. Modeling the 

dispersive effects of smaller-scale heterogeneities and 

anisotropies within this larger-scale model is possible 

using local grid refinement that includes refinement of the 

hydrogeologic framework in areas affected by contamination 

and where data are sufficient for refinement.

Acknowledgments

The authors are grateful for many helpful suggestions 

and comments made by Claire Tiedeman and Dave Pollock as 

part of the USGS internal program reviews for the study. Their 

guidance and encouragement, are appreciated. 

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Reactor Testing Station, Idaho: U.S. Geological Survey 

Professional Paper 725-B, 49 p.

Nimmo, J.R., Perkins, K.S., Rose, P.A., Rousseau, J.P., Orr, 

B.R., Twining, B.V., and Anderson, S.R., 2002, Kilometerscale rapid transport of naphthalene sulfonate tracer in the 

unsaturated zone at the Idaho National Engineering and 

Environmental Laboratory: Vadose Zone Journal, v. 1, no. 1, 

p. 89-101.

Perkins, K.S., 2008, Laboratory-measured and propertytransfer modeled saturated hydraulic conductivity of 

Snake River Plain aquifer sediments at the Idaho National 

Laboratory, Idaho: U.S. Geological Survey Scientific 

Investigations Report, 2008-5169, DOE/ID-22207, 14 p., 

available online at http://pubs.usgs.gov/sir/2008/5169/.

Pittman, J.R., Jensen, R.G., and Fischer, P.R., 1988, 

Hydrologic conditions at the Idaho National Engineering 

Laboratory, 1982 to 1985: U.S. Geological Survey WaterResources Investigations Report 89-4008, DOE/ID-22078, 

73 p.

Plummer, L.N., Rupert, M.G., Busenberg, E., and Schlosser, 

P., 2000, Age of irrigation water in groundwater from the 

Snake River Plain aquifer, South-Central Idaho: Ground 

Water, v. 38, p. 264-283.

Pollock, D.W., 1994, User’s guide for MODPATH/

MODPATH-PLOT, version 3–a particle tracking postprocessing package for MODFLOW, the U.S. Geological 

Survey finite-difference ground-water flow model: U.S. 

Geological Survey Open-File Report 94-464, 245 p.

Robertson, J.B., 1974, Digital modeling of radioactive and 

chemical waste transport in the Snake River Plain aquifer at 

the National Reactor Testing Station, Idaho: U.S. Geological 

Survey Open-File Report, IDO-22054, 41 p. 
References Cited 139

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.

Schaffer-Perini., A.L., 1993, Test Area North groundwater 

remedial investigation/feasibility study contaminant fate 

and transport modeling results: Idaho Falls, Idaho, EWR 

WAG1-21, EG&G Idaho, Inc., Idaho National Engineering 

and Environmental Laboratory [variously paged].

Spear, D.B., and King, J.S., 1982, The geology of 

Big Southern Butte, Idaho, in Bonnichsen, B., and 

Breckenridge, R.M., eds., Cenozoic Geology of Idaho: 

Idaho Bureau of Mines and Geology Bulletin 26, p. 395-403

Spinazola, J.M., 1994, Geohydrology and simulation of flow 

and water levels in the aquifer system in the Mud Lake 

area of the eastern Snake River Plain, eastern Idaho: U.S. 

Geological Survey Water–Resources Investigations Report 

93-4227, 78 p. 

Stearns, H.T., Bryan, L.L., and Crandall, Lynn, 1939, 

Geology and water resources of the Mud Lake basin, Idaho, 

including the Island Park area: U.S. Geological Survey 

Water-Supply Paper 818, 125 p

Stearns, H.T., Crandall, Lynn, and Steward, W.G., 1938, 

Geology and ground-water resources of the Snake River 

Plain in southeastern Idaho: U.S. Geological Survey WaterSupply Paper 774, 268 p.

Stroup, C.N., Welhan, J.A., and Davis, L.C., 2008, Statistical 

stationarity of sediment interbed thicknesses in a basalt 

aquifer, Idaho National Laboratory, eastern Snake 

River Plain, Idaho: U.S. Geological Survey Scientific 

Investigations Report 2008–5167, DOE/ID-22204, 20 p., 

available online at http://pubs.usgs.gov/sir/2008/5167/.

U.S. Environmental Protection Agency, 1991 Sole source 

designation of the Eastern Snake River Plain Aquifer, 

Southern Idaho: Federal Register, v. 56, no. 194, p. 50634.

Welhan, J.A., Clemo, T.M., and Gégo, E.L., 2002, Stochastic 

simulation of aquifer heterogeneity in a layered basalt 

aquifer system, eastern Snake River Plain, Idaho, in Link, 

P.K., and Mink, L.L., eds., Geology, Hydrogeology, and 

Environmental Remediation–Idaho National Engineering 

and Environmental Laboratory, Eastern Snake River Plain, 

Idaho: Geological Society of America Special Paper 353, 

p. 225-247.

Welhan, J.A., Farabaugh, R.L., Merrick, M.J., and Anderson, 

S.R., 2007, Geostatistical modeling of sediment abundance 

in a heterogeneous basalt aquifer at the Idaho National 

Laboratory, Idaho: U.S. Geological Survey Scientific 

Investigations Report 2006-5316, DOE/ID-22201, 32 p., 

available online at http://pubs.usgs.gov/sir/2006/5316/.

Welhan, J.A., and Wylie, A.H., 1997, Stochastic modeling of 

hydraulic conductivity in the Snake River Plain aquifer–2. 

Evaluation of lithologic controls at the core and borehole 

scales, in Sharma, S., and Hardcastle, J.H., eds., Symposium 

on Engineering Geology and Geotechnical Engineering, 

32nd, Boise, Idaho, 1997 [Proceedings], p. 93-107.

Whitehead, R.L., 1986, Geohydrologic framework of the 

Snake River Plain, Idaho and eastern Oregon: U.S. 

Geological Survey Hydrologic Investigations Atlas HA-681, 

scale 1:1,000,000, 3 sheets.

Whitehead, R.L., 1992, Geohydrologic framework of the 

Snake River Plain regional aquifer system, Idaho and 

eastern Oregon: U.S. Geological Survey Professional Paper 

1408-B, 32 p.

Wood, T.R., and Norrell, G.T., 1996, Integrated largescale aquifer pumping and infiltration tests, groundwater 

pathways, OU 7-06, summary report: INEL-96/0256, Rev.0 

[variously paged].
140 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

This page intentionally left blank.
Appendix A 141

Appendix A. Data for Wells, Boreholes, and Streams Used 

in the Construction and Calibration of Steady-State and 

Transient Models of Groundwater Flow, Idaho National 

Laboratory and Vicinity, Idaho
142 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

1 434819112380501 2ND OWSLEY 310 302 B2 X X

2 434556112575601 434556 350 350 B2 X X

3 434647112534101 434647 600 600 B2 X X

4 434650112545501 434650 816 816 B2 X X

5 434714112175801 434714 300 300 B2 X X

6 434726112244101 434726 – – B2 X X

7 434756112212101 434756 292 290 B2 X X

8 435026112253101 435026 270 270 B2 X X

9 435100112271601 435100 247 247 B2 X X

10 440109112391301 440109 380 380 B2 X X

11 432853113021701 A11A31 678 675 B1, B3 128

12 433534112392901 ANL MW 11 677 654 B9 X X

13 433545112394102 ANL MW 13 668 665 B9 X X

14 433545112394101 ANL OBS A 001 1,910 1,910 B9 X X

15 – ANL-IWP-M1 54 54 B9 129

16 – ANL-IWP-M2 80 80 B9 130

17 – ANL-IWP-M3 60 45 B9 131

18 – ANL-IWP-M4 68 30 B9 132

19 – ANL-IWP-M5 64 64 B9 133

20 – ANL-IWP-M6 423 406 B9 134

21 435308112454101 ANP 5 396 396 B2 X X

22 435152112443101 ANP 6 305 305 B2, B4 135 X X

23 435522112444201 ANP 7 436 433 B2 136 X X

24 434952112411301 ANP 8 309 309 B4 X

25 434856112400001 ANP 9 322 322 B2 137 X X

26 434909112400401 ANP 10 681 681 B2 138 X X

27 435053112423201 ANP DISP 3 310 310 B4 X X

28 433107112492201 ARA 2 787 787 B2 X

29 433156112494401 ARA 3 1,340 1,340 B2 X

30 433509112384801 ARBOR TEST 790 790 B9 140 X X

31 433223112470201 AREA 2 877 877 B2 139 X X

32 435016112311201 Ashcraft 420 360 B2 142

33 432638112484101 ATOMIC CITY 

WELL

– – B2

34 433042112535101 BADGING 

FACILITY

– – B2 221 X

35 435003112313101 Barney North 660 660 B2 152

36 434950112311201 Barney South 596 – B2 153
Appendix A 143

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

37 – BG-76-1 228 – B3 143

38 – BG-76-2 253 – B3 144

39 – BG-76-3 240 – B3 145

40 – BG-76-4 215 – B3 146

41 – BG-76-4A 254 – B3 147

42 – BG-76-5 245 – B3 148

43 – BG-76-6 244 – B3 149

44 – BG-77-1 600 – B3 150

45 – BG-77-2 87 – B3 151

46 433631113143702 Butte City #2 850 475 B1 154

47 – C-1 664 – B3 155

47 – C-1A 1,805 – B3 156

48 434949112300101 Callaway 650 650 B2 172

49 432618112555501 CERRO GRANDE 564 564 B2 173 X X

50 433204112562001 CFA 1 685 639 B8 157 X

51 433144112563501 CFA 2 681 681 B8 158 X X X

52 – CFA 4 – – B2, B8 159

53 433216112563201 CFA LF 2-8 526 495 B8 160

54 433217112563401 CFA LF 2-9 676 497 B8 161

55 433216112563301 CFA LF 2-10 816 716 B8 162 X X

56 433230112561701 CFA LF 2-11 511 499 B8 163 X X

57 433217112563601 CFA LF 2-12 517 490 B8 164

58 433218112571001 CFA LF 3-8 526 510 B8 165

59 433216112571001 CFA LF 3-9 517 500 B8 166 X X

60 433222112571901 CFA LF 3-10 530 501 B8 167

61 433249112565501 CFA LF 3-11 532 492 B8 168

62 435213112302001 Cope 784 784 B2 174

63 432927112410101 COREHOLE 1 2,002 2,000 B2 175 X X

64 434558112444801 COREHOLE 2A 3,000 3,000 B2 176

65 431519113112901 COX WELL 777 777 B1 X X

66 433433112560201 CPP 1 586 586 B7 X

67 433432112560801 CPP 2 605 605 B7 169 X

68 433413112560401 CPP 3 598 598 B7 170 X

69 433440112554401 CPP 4 700 700 B7 171 X X X

69 433440112554402 CPP 5 721 721 B7 X X

70 432128113092701 CROSS ROAD 796 796 B1
144 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

71 – D-10 – – B3 177

72 – D-15 – – B3 178

73 435817112365401 Dahle 232 232 B2 186

74 434611112504301 DH 1B 400 400 B2 179 X X

75 434547112512801 DH 2A 430 425 B2 180 X X

76 – DH3 – – B2 181

77 – DH-50 250 – B2, B9 182

78 – DO-2 235 – B3 183

79 – DO-6 126 – B3 184

79 – DO-6A 50 – B3 185

80 433051113002601 EBR 1 1,075 1,075 B1, B2 187 X

81 433546112391601 EBR 2-1 747 745 B9 X

82 433544112391301 EBR II-2 753 753 B9 X

83 431831113312901 ELLSWORTH 1,305 1,305 B1 X X

84 433120112535101 EOCR 1,237 1,237 B2 189

85 – EOCR (Disp) – – B2 190

86 435120112432101 FET 1 339 330 B4 X

87 435119112431801 FET 2 462 455 B4 X

88 435124112433701 FET DISP 3 302 300 B4 191 X X X

89 433548112562301 FIRE STA 2 518 510 B2 X

90 432424113165301 FNGR BUTTE 1,056 1,056 B1 X X

91 434947112414301 GIN 1 (new) 373 364 B4 X

91 434947112414301 GIN 1 (old) 373 373 B4 192 X X

92 434949112413401 GIN 2 402 381 B4 193 X X

93 434945112413101 GIN 3 (new) 386 378 B4 X

93 434945112413101 GIN 3 (old) 386 386 B4 194 X X

94 434949112413601 GIN 4 306 300 B4 195 X X

95 434953112413301 GIN 5 (new) 430 285 B4 X

95 434953112413301 GIN 5 (old) 430 285 B4 196 X X

96 – GIN #6 – – B4 197

97 – GIN #7 – – B4 198

98 – GIN #8 – – B4 199

99 – GIN #9 – – B4 200

100 – GIN #10 – – B4 201

101 – GIN #11 – – B4 202
Appendix A 145

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

102 – GIN #12 – – B4 203

103 – GIN #13 – – B4 204

104 – GIN #14 – – B4 205

105 – GIN #15 – – B4 206

106 – GIN #16 – – B4 207

107 – GIN #17 – – B4 208

108 – GIN #18 – – B4 209

109 – GIN #19 – – B4 210

110 – GIN #20 – – B4 211

111 433218112191603 HIGHWAY 1A 1,302 1,147 B2 212

111 433218112191602 HIGHWAY 1B 1,038 982 B2

111 433218112191601 HIGHWAY 1C 883 800 B2

112 433307112300001 HIGHWAY 2 786 786 B2 214

113 433256113002501 HIGHWAY 3 750 750 B1, B2 215

114 431439113071401 Houghland 775 775 B1 X X

115 435153112420501 IET 1 DISP 329 324 B2, B4 216 X X

116 433717112563501 INEL 1 10,365 10,333 B2 217

117 432533112504901 LEO ROGERS 1 720 720 B2 278

118 434946112412401 LPTF DISP 314 314 B4 219 X

119 433418112581701 MIDDLE 1823 1,653 720 B6

120 433217113004901 MIDDLE 2051 1,179 1,175 B1, B2

121 434700112530401 ML 11 601 601 B2 X X

122 434558112585301 ML 12 540 540 B1, B2 X X

123 434723112552701 ML 13 650 650 B2 X X

124 433520112572601 MTR TEST 588 588 B6 220 X X

125 432956113041401 NA 89-1 238 232 B1 222

126 433056113045101 NA 89-2 235 230 B1 223

127 432918113031701 NA 89-3 184 180 B3 224

128 435038112453401 NO NAME 1 550 550 B2 320 X X

129 433449112523101 NPR TEST 600 600 B2 225 X X

130 433451112523201 NPR WO-2 5,000 5,000 B2 226

131 433859112545401 NRF 1 535 535 B5 X

132 433854112545401 NRF 2 529 528 B5 X

133 433858112545501 NRF 3 546 546 B5 X

134 433853112545901 NRF 4 – – B5 228 X
146 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

135 433844112550201 NRF #5 – – B5 279

136 433910112550101 NRF 6 417 417 B5 229 X X

137 – NRF #6P 500 494 B5 230

138 433920112543601 NRF 7 430 415 B5 231 X X

139 – NRF #7P 500 – B5 232

140 433843112550901 NRF 8 425 423 B5 X X

141 433840112550201 NRF 9 425 422 B5 X X

142 433841112545201 NRF 10 450 427 B5 X X

143 433847112544201 NRF 11 425 417 B5 X X

144 433855112543201 NRF 12 425 421 B5 X X

145 433928112545401 NRF 13 425 425 B5 X X

146 – NRF 89-04 248 – B5 233

147 – NRF 89-05 242 – B5 234

148 – OW-1 1,000 1,000 B3 235

149 – OW-2 1,000 1,000 B3 236

150 435416112460401 P&W 1 432 432 B2 241 X X

151 435419112453101 P&W 2 386 386 B2 242 X X

152 435443112435801 P&W 3 406 406 B2 243 X X

153 – PBF (CW) – – B2 238

154 – PBF (WW) – – B2 239

155 434941112454201 PSTF TEST 322 319 B2 240 X X

156 433349112560701 PW-1 119 119 B7 244

157 433344112555601 PW-2 131 131 B7 245

158 433351112555701 PW 3 123 123 B7 246

159 433348112554901 PW 4 150 150 B7 247

160 433348112555701 PW 5 131 129 B7 248

161 433353112562201 PW 6 135 125 B7 249

162 433446112574602 PW 7 237 237 B6 250

163 433456112572001 PW 8 178 170 B6 251

164 433500112575401 PW 9 201 200 B6 252

165 433512112573701 PW 10 150 128 B6 253

166 433505112572201 PW 11 169 129 B6 254

167 433510112574901 PW 12 142 128 B6 255

168 433505112574101 PW 13 149 88 B6 256

169 433518112573401 PW 14 136 123 B6 257
Appendix A 147

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

170 432632113095901 QAB 1,115 1,115 B1 258 X X

171 434857112185801 R. Archer 260 260 B2 141

172 433243112591101 RIFLE RANGE – – B1, B2 277

173 – RWMC-78-1 82 – B3 259

174 – RWMC-78-2 253 – B3 260

175 – RWMC-78-3 248 – B3 261

176 – RWMC-78-4 – – B3 262

177 – RWMC-78-5 250 – B3 263

178 – RWMC-79-1 244 – B3 264

179 – RWMC-79-2 223 – B3 265

180 – RWMC-79-3 262 – B3 266

181 – RWMC-88-02D – – B3 268

182 – RWMC-88-1D – – B3 267

183 – RWMC-89-01D – – B3 269

184 432956113030901 RWMC M1SA 678 638 B3 270 X X

185 433008113021801 RWMC M3S 660 633 B3 271 X X

186 432939113030101 RWMC M4D 838 828 B3 272 X X

187 432931113015001 RWMC M6S 697 668 B1, B3 273 X X

188 433023113014801 RWMC M7S 638 628 B3 274 X X

189 432949113024301 RWMC M10S 678 648 B3 275

190 432919113031199 RWMC-PRO-A-064 848 848 B3

191 433002113021701 RWMC PROD 685 685 B3 276 X

192 – Sdd-1 – – B2 280

193 – Sdd-2 – – B2 281

194 – Sdd-3 – – B2 282

195 434744112212202 Siddoway 930 715 B2 283

196 432854113201002 SITE 1 1,053 1,053 B1 334 X X

197 431946113161401 SITE 2 1,041 1,041 B1 127 X X

198 433617112542001 SITE 4 495 495 B2 188

199 433826112510701 SITE 6 523 523 B2 284 X X

200 433123112530101 SITE 9 1,131 1,057 B2 285 X X

201 434334112463101 SITE 14 717 717 B2 286 X X

202 433545112391501 SITE 16 758 758 B9 287 X X

203 434027112575701 SITE 17 600 600 B2 288 X X

204 433522112582101 SITE 19 865 860 B6 289 X X
148 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

205 433252112520301 SPERT 1 653 653 B2 X

206 433247112515201 SPERT 2 1,217 1,217 B2 237 X

207 435056112420001 TAN 1 365 355 B2, B4 X X X

208 435100112420701 TAN 2 346 335 B4 X X X

209 435104112420301 TAN 3 269 264 B4 290 X X

210 435055112421301 TAN 4 247 245 B4 291

210 435055112421302 TAN 5 303 303 B4 292 X X

211 435039112412601 TAN 6 263 255 B4 293 X X

212 435038112412601 TAN 7 324 317 B4 294 X X

213 435034112421701 TAN 8 251 250 B4 295 X X

214 435053112423202 TAN 9 326 322 B4 296 X X

215 435050112423201 TAN #10 258 245 B4 297

216 435051112423201 TAN 10 A 250 250 B4 298 X X

217 435050112423202 TAN 11 313 310 B4 299 X X

218 435050112423301 TAN 12 394 384 B4 300

219 435040112423701 TAN 13 255 – B4 301 X X

220 435040112423801 TAN 13A 244 236 B4 302 X X

221 435039112423701 TAN 14 404 396 B4 303 X X

222 435021112412701 TAN 15 255 252 B4 304 X X

223 435020112412701 TAN #16 325 299 B4 305

224 435034112421601 TAN 17 351 340 B4 306 X X

225 435051112421401 TAN 18 519 516 B4 307 X X

226 435051112421501 TAN 19 453 416 B4 308 X X

227 435046112425001 TAN 20 400 372 B4 309 X X

228 435009112420001 TAN 21 520 451 B4 310 X X

229 435020112412702 TAN 22 513 – B4 311 X X

230 435019112412701 TAN 22A 539 531 B4 312 X X

231 435020112412703 TAN 23 507 – B4 313 X X

231 435020112412704 TAN 23A 467 455 B4 314 X X

232 434942112411101 TAN 24 481 – B4 315 X X

232 434942112411001 TAN 24A 478 238 B4 316 X X

233 435058112423401 TAN CH 1 600 294 B4 321 X X

234 435033112421702 TAN CH 2B 1,114 1,090 B4 322 X X

235 435042112420901 TAN Drainage 

Disp.#1

325 315 B4 317

236 435054112423201 TAN Drainage 

Disp.#2

262 252 B4 318
Appendix A 149

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

237 435116112430301 TAN Drainage 

Disp.#3

302 300 B4 319

238 433521112573801 TRA 1 600 600 B6 X

239 433521112574201 TRA 2 772 747 B6

240 433522112573501 TRA 3 602 602 B6 323 X

241 433453112574901 TRA 5 PZ1 297 128 B6 325

242 433446112574701 TRA 6 562 558 B6 326 X X

243 433449112575901 TRA 7 501 493 B6 327 X X

244 433431112580101 TRA 8 502 502 B6 328 X X

245 433506112572301 TRA DISP 1,275 1,267 B6 329 X X X

246 – TW-1 238 – B3 330

247 432700112470801 USGS 1 636 636 B2 1 X X

248 433320112432301 USGS 2 704 699 B2 2 X X

249 433732112335401 USGS 3A 740 733 B2 3

250 434657112282201 USGS 4 553 553 B2 4 X X

251 433543112493801 USGS 5 500 494 B2 5 X X

252 434031112453701 USGS 6 620 620 B2 6 X X

253 434915112443901 USGS 7 1,200 903 B2 7 X X

254 433121113115801 USGS 8 812 812 B1 8 X X

255 432740113044501 USGS 9 654 654 B1 9 X X

256 432336113064201 USGS 11 704 704 B1 10 X X

257 434126112550701 USGS 12 692 563 B2 11 X X

258 432731113143902 USGS 13 1,200 1,010 B1 12 X X

259 432019112563201 USGS 14 752 752 B2 13 X X

260 434234112551701 USGS 15 1,497 610 B2 14 X X

261 431333113001701 USGS 16 740 739 B1, B2 15

262 433937112515401 USGS 17 498 498 B2 16 X X

263 434540112440901 USGS 18 329 329 B2 17 X X

264 434426112575701 USGS 19 405 399 B2 18 X X

265 433253112545901 USGS 20 676 658 B2 19 X X

266 434307112382601 USGS 21 406 363 B2 20 X X

267 433422113031701 USGS 22 657 657 B1 21 X X

268 434055112595901 USGS 23 467 458 B1, B2 22 X X

269 435053112420801 USGS 24 326 326 B4 23 X X

270 435339112444601 USGS 25 320 320 B2 24 X X

271 435212112394001 USGS 26 267 267 B2 25 X X
150 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

272 434851112321801 USGS 27 312 312 B2 26 X X

273 434600112360101 USGS 28 334 334 B2 27 X X

274 434407112285101 USGS 29 426 426 B2 28 X X

275 434601112315403 USGS 30A 1,007 725 B2 29 X X

275 434601112315402 USGS 30B 1,007 400 B2 X X

275 434601112315401 USGS 30C 1,007 300 B2 X X

276 434625112342101 USGS 31 428 428 B2 30 X X

277 434444112322101 USGS 32 392 392 B2 31 X X

278 434314112322901 USGS 33 516 516 B2 32

279 433334112565501 USGS 34 700 700 B7 33 X X

280 433339112565801 USGS 35 579 579 B7 34 X X

281 433330112565201 USGS 36 567 567 B7 35 X X

282 433326112564801 USGS 37 573 572 B7 36 X X

283 433322112564301 USGS 38 729 612 B7 37 X X

284 433343112570001 USGS 39 572 494 B7 38 X X

285 433411112561101 USGS 40 679 483 B7 39 X X

286 433409112561301 USGS 41 674 666 B7 40 X X

287 433404112561301 USGS 42 678 678 B7 41 X X

288 433415112561501 USGS 43 676 676 B7 42 X X

289 433409112562101 USGS 44 650 650 B7 43 X X

290 433402112561801 USGS 45 651 651 B7 44 X X

291 433407112561501 USGS 46 651 651 B7 45 X X

292 433407112560301 USGS 47 651 651 B7 46 X X

293 433401112560301 USGS 48 750 750 B7 47 X X

294 433403112555401 USGS 49 656 458 B7 48 X X

295 433419112560201 USGS 50 405 395 B7 49

296 433350112560601 USGS 51 659 647 B7 50 X X

297 433414112554201 USGS 52 650 602 B7 51 X X

298 433503112573401 USGS 53 90 90 B6 52

299 433503112572801 USGS 54 91 91 B6 53

300 433508112573001 USGS 55 81 81 B6 54

301 433509112573501 USGS 56 80 80 B6 55

302 433344112562601 USGS 57 732 582 B7 56 X X

303 433500112572502 USGS 58 503 503 B6 57 X X

304 433354112554701 USGS 59 657 587 B7 58 X X
Appendix A 151

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

305 433456112571901 USGS 60 117 117 B6 59

306 433453112571601 USGS 61 123 123 B6 60

307 433446112570701 USGS 62 165 165 B6, B7 61

308 433455112574001 USGS 63 97 97 B6 62

309 433513112571801 USGS 64 205 205 B6 63

310 433447112574501 USGS 65 498 498 B6 64 X X

311 433436112564801 USGS 66 475 475 B6, B7 65

312 433344112554101 USGS 67 694 694 B7 66 X X

313 433516112573901 USGS 68 128 128 B6 67

314 433450112573001 USGS 69 115 115 B6 68

315 433504112571001 USGS 70 100 100 B6 69

316 433439112571501 USGS 71 184 171 B6 70

317 433519112574601 USGS 72 200 200 B6 71

318 433502112575401 USGS 73 127 127 B6 72

319 433505112580501 USGS 74 192 192 B6 73

320 433457112570001 USGS 75 212 212 B6 74

321 433425112573201 USGS 76 718 718 B6 75 X X

322 433315112560301 USGS 77 610 586 B7 76 X X

323 433413112573501 USGS 78 204 204 B6 77

324 433505112581901 USGS 79 702 702 B6 78 X X

325 433457112570002 USGS 80 204 204 B6 79

326 433400112551001 USGS 81 104 104 B7 80

327 433401112551001 USGS 82 700 693 B7 81 X X

328 433023112561501 USGS 83 752 752 B2 82 X X

329 433356112574201 USGS 84 505 505 B6 83 X X

330 433246112571201 USGS 85 (new) 637 614 B8 X

330 433246112571201 USGS 85 (old) 637 637 B8 84 X X

331 432935113080001 USGS 86 691 691 B1 85 X X

332 433013113024201 USGS 87 673 673 B3 86 X X

333 432940113030201 USGS 88 663 663 B3 87 X

334 433005113032801 USGS 89 650 637 B3 88 X X

335 432954113020501 USGS 90 626 626 B3 89 X X

336 – USGS 91 255 – B3 90

337 433000113025301 USGS 92 247 214 B3 91

338 – USGS 93 246 – B3 92
152 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

338 – USGS 93A 233 – B3 93

339 – USGS 94 302 – B3 94

340 – USGS 95 246 – B3 95

341 – USGS 96 236 – B3 96

341 – USGS 96A 120 – B3 97

342 – USGS 96B 229 – B3 98

343 433807112551501 USGS 97 510 510 B2, B5 99 X X

344 433657112563601 USGS 98 508 508 B2 100 X X

345 433705112552101 USGS 99 450 440 B2 101 X X

346 433503112400701 USGS 100 750 750 B9 102 X X

347 433255112381801 USGS 101 865 842 B2 103 X X

348 433853112551601 USGS 102 445 445 B5 104 X X

349 432714112560701 USGS 103 1,307 1,297 B2 105 X X

350 432856112560801 USGS 104 700 700 B2 106 X X

351 432703113001801 USGS 105 800 800 B1, B2 107 X X

352 432959112593101 USGS 106 760 760 B1, B2 108 X X

353 432942112532801 USGS 107 690 690 B2 109 X X

354 432659112582601 USGS 108 760 760 B2 110 X X

355 432701113025601 USGS 109 800 800 B1 111 X X

356 432717112501501 USGS 110 780 780 B2 112 X X

356 432717112501502 USGS 110A 657 644 B2 X

357 433331112560501 USGS 111 600 560 B7 113 X X

358 433314112563001 USGS 112 563 563 B7 114 X X

359 433314112561801 USGS 113 564 564 B7 115 X X

360 433318112555001 USGS 114 563 560 B7 116 X X

361 433320112554101 USGS 115 581 581 B7 117 X X

362 433331112553201 USGS 116 580 572 B7 118 X X

363 432955113025901 USGS 117 655 655 B3 119 X X

364 432947113023001 USGS 118 622 608 B3 120 X X

365 432945113023401 USGS 119 705 705 B3 121 X X

366 432919113031501 USGS 120 705 705 B3 122 X X

367 433450112560301 USGS 121 746 475 B7 123 X X

368 433353112555201 USGS 122 483 480 B7 124 X X

369 433352112561401 USGS 123 744 515 B7 125 X X

370 432307112583101 USGS 124 800 800 B2 126 X X
Appendix A 153

Table A1. Data for wells and boreholes used in the construction and calibration of steady-state and transient models of groundwater 

flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells in appendix B figures and as a cross reference with data in other appendixes. Site identifier: Unique numerical 

identifier used to access well data (http://waterdata.usgs.gov/nwis). Local name: Local well identifier used in this study. Stratigraphic data No.: Cross 

reference to borehole locations used by Anderson, Ackerman, and others (1996) and Anderson, Liszewski, and Ackerman (1996) used to construct the 

hydrogeologic framework of the models. Abbreviation: ft-bls, foot below land surface. Symbols: –, data not available; X, entry in specified appendix tables]

Map 

No. Site identifier Local name Depth of hole (ft-bls)

Depth of well 

(ft-bls)

Appendix 

figure No.

Stratigraphic 

data No.

Data in table

G1 H1 C1 F1

371 432602113052801 USGS 125 774 774 B1 X X

372 432906113025001 USGS 132 1,238 1,238 B3

373 – VZT-1 – – B3 331

374 440813112532201 Wagoner Ranch 295 295 B2

375 433445113202801 Weaver and Lowe 1,075 1,025 B1 335 X X

376 433716112563601 WS INEL 1 710 490 B2 218 X X

377 – WWW#1 – – B3 332

378 – WWW#2 – – B3 333

379 433116112534701 OMRE 943 943 B2

380 433521112574201 TRA 4 970 965 B6 324 X
154 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table A2. Data for streams used in the construction and calibration of steady-state and transient 

models of groundwater flow, Idaho National Laboratory and vicinity, Idaho.

[Map No.: Identifier used to locate streamflow-gaging stations and stream reaches on maps in appendix B figures and as 

a cross reference with appendix C. Site identifier: Unique numerical identifier used to access streamflow-gaging station 

data (http://waterdata.usgs.gov/nwis). Local name: Local streamflow-gaging station or stream-reach identifier used in 

this study]

Map 

No. Site identifier Local name Appendix figure No.

Streamflow-gaging stations

500 13127000 Big Lost River below Mackay Reservoir near Mackay B1

501 12132500 Big Lost River near Arco B1

502 13132513 INL Diversion at Head, near Arco B1

503 13132515 INL Diversion at Outlet of Spreading Area A near Arco B1

504 13132520 Big Lost River below INL diversion, near Arco B1

505 13132535 Big Lost River at Lincoln Boulevard Bridge near Atomic City B2, B6, B7

506 13132565 Big Lost River above Big Lost River Sinks near Howe B2

Stream reaches

600 Big Lost River above Arco gage (13132500) B1

601 Big Lost river between Arco gage (13132500) and INL Diversion B1

602 Spreading Area A B1

603 Spreading Area B B1, B3

604 Spreading Area C B1

605 Spreading Area D B1

606 Big Lost River between INL diversion and Lincoln Boulevard 

gage (13132535)

B1, B2, B6, 

B7

607 Big Lost River between Lincoln Boulevard gage (13132535) and 

Big Lost River Sinks gage (13132565)

B2, B6, B7

608 Big Lost River Sinks B2

609 Big Lost River Playas 1 and 2 B2

610 Big Lost River Playa 3 B2, B4

611 Little Lost River B2

612 Birch Creek power diversion return B2
Appendix B 155

Appendix B. Locations of Wells and Streams for Which 

Stratigraphic, Water-Level, Water-Use, and Discharge 

Data are Available, Idaho National Laboratory and 

Vicinity, Idaho
156 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. B1

IDAHO

BOISE

EASTERN 

SNAKE RIVER

PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

500

501

502

113°45' 113°30' 113°15' 113°00'

44°

00'

43°

45'

43°

30'

43°

15'

Lost

River

Little

Lost

Big

River

B3

ARCO

Mackay

Reservoir

Idaho National Laboratory HOWE

boundary

Model area

Area of appendix figures 

B3 to B9

EXPLANATION

Well and number that

identifies the well in

appendix table A1

Stream gage and number

that identifies the gage

in appendix table A2

Stream reach and number

that identifies the reach

in appendix table A2

606

254

504

601

606

600

604 605

603

602

504

503

375

371

355

352

351

331

268

267

261

258

256

255

254

197

196

172

170

126

125

122

120

114

113

90

83

80

70

65

46

0 5

5

10

10

15

15

Miles

0 Kilometers

B3

611

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.

Figure B1. Locations of wells and streams for which stratigraphic, water-level, water-use, and 

discharge data are available, western half of study area, Idaho National Laboratory and vicinity, Idaho. 

Click on well, stream gage, or reach number to access information in tables A1 or A2.
Appendix B 157

ID19-0164_GWflow_fig. B2

IDAHO

BOISE

EASTERN 

SNAKE RIVER PLAIN IDAHO 

NATIONAL

LABORATORY

Twin

Falls

Pocatello

Idaho

Falls

612

607

606

611

610

609

608

506

505

374

376

370

356 354

353

379

352

351

350

349

347

345

344

328

278

277

276 275

274

273

272

271

270

268

266

265

264

263

262

261

260

259

257

253

252

251

250

249

248

247

207

206

205

203

201

200

199

198

195

194 193

192 172

171

155

154

153

152 151

150

130

129

128

123

122

121

120

117

116

113

112 111

89

85

84

80

77

76 75

74

73

64

63

62

49

48 36

35

34

33

32

31 29

28

26

25

23

22

21

10

9

8

7

6 5

4

3

2

1

TERRETON

MUD

LAKE

Mud

Lake

HOWE

113°00' 112°45' 112°30' 112°15'

44°

00'

43°

45'

43°

30'

43°

15'

B8

B7

B6

B5

B4

B9

0 5

5

10

10

15

15

Miles

0 Kilometers

ATOMIC

CITY

Idaho National Laboratory

boundary

Model area

EXPLANATION

Well and number that

identifies the well in

appendix table A1

Stream gage and number

that identifies the gage

in appendix table A2

Stream reach and number

that identifies the reach

in appendix table A2

606

111

505

Area of appendix figures 

B4 to B9

B4

Birch

Creek

Camas Cr

Big

Lost River

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.

Figure B2. Locations of wells and streams for which stratigraphic, water-level, water-use, and 

discharge data are available, eastern half of study area, Idaho National Laboratory and vicinity, Idaho.

Click on well, stream gage, or reach number to access information in tables A1 or A2.
158 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. B3

603

378 377

373

372

366

365 364

363

342

341

340

339

338

337

336

335

334

333

332

246 191

190

189

188

187

186

185

184 183

182

181

180

179

178 177

176

175

174

173

149

148

127

79 78

72

71

47

45

44

43

42

41 40

39

38

37

11

113°03' 113°02'

43°

30'

43°

29'

Radioactive

Waste

Management

Complex

0 0.25 0.5 Mile

0 0.25 0.5 Kilometer

Stream reach and number that 

identifies the reach in 

appendix table A2

11

EXPLANATION

Well and number that identifies 

the well in appendix table A1

603

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.

Figure B3. Locations of wells and streams for which stratigraphic, water-level, water-use, and discharge data 

are available at the Radioactive Waste Management Complex, Idaho National Laboratory, Idaho.

Click on well, stream gage, or reach number to access information in tables A1 or A2.
Appendix B 159

ID19-0164_GWflow_fig. B4

610

269

237

236

235

234

233

232

232

231 230

229

228

227

226 225

224

222 223

221

220 219

218

217

216

215

214

213 212

211

210

209

208

207

118

115

110

109

107 108

106

105 104

103

102

101

100

99

98

97

96

95

94

93

92 91

88

87

86

27

24

22

112°44' 112°43' 112°42' 112°41'

43°

52'

43°

51'

43°

50'

43°

49'

Test

Area

North

Stream reach and number that 

identifies the reach in 

appendix table A2

0 0.5 1 Mile

0 0.5 1 Kilometer

93

EXPLANATION

Well and number that identifies 

the well in appendix table A1

610

Birch

Creek

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.

Figure B4. Locations of wells and streams for which stratigraphic, water-level, water-use, and discharge data 

are available at the Test Area North, Idaho National Laboratory, Idaho.

Click on well, stream gage, or reach number to access information in tables A1 or A2.
160 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. B5

348

343

147

146

145

144

143

142

141

140

139

138

137

136

135

134

133

132

131

112°55' 112°54'

43°

39'

43°

38'

Naval

Reactors

Facility

142

EXPLANATION

Well and number that identifies 

the well in appendix table A1

0 0.25 0.5 Mile

0 0.25 0.5 Kilometer

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.

Figure B5. Locations of wells and streams for which stratigraphic, water-level, water-use, and discharge data are 

available at the Naval Reactors Facility, Idaho National Laboratory, Idaho. 

Click on well, stream gage, or reach number to access information in tables A1 or A2.
Appendix B 161

ID19-0164_GWflow_fig. B6

606

607

505

329

325

324

323

321

320

319

318

317

316

315

314

313

311

310

309

308

307

306

305

303

301 300

299 298

245

244

243

242

241

239

240238 380

204

169

168

167

166

165

164

163

162

124

119

112°58' 112°57'

43°

35'

43°

34'

Reactor

Tecnology

Complex

EXPLANATION

Well and number that 

identifies the well in 

appendix table A1

Stream gage and number

that identifies the gage in

appendix table A2

Stream reach and number

that identifies the reach in

appendix table A2

606

315

505

0 0.25 0.5 Mile

0 0.25 0.5 Kilometer

Big

Lost

Creek

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.

Figure B6. Locations of wells and streams for which stratigraphic, water-level, water-use, and discharge data are 

available at the Reactor Technology Complex, Idaho National Laboratory, Idaho. 

Click on well, stream gage, or reach number to access information in tables A1 or A2.
162 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. B7

505

369 368

367

362

361

360

358 359

357

327

326

322

312

311

307

304

302

297

296

295

294

293

292 291

290

289

288

287

286

285

284

283

282

281

280

279

161

160 159

158

157

156

69

68

67 66

112°57' 112°56'

43°

34'

43°

34'

40"

Idaho Nuclear

Technology and

Engineering

Center

606

607

EXPLANATION

Well and number that 

identifies the well in 

appendix table A1

Stream gage and number

that identifies the gage in

appendix table A2

Stream reach and number

that identifies the reach in

appendix table A2

606

69

43°

33'

20"

505

0 0.25 0.5 Mile

0 0.25 0.5 Kilometer

Big

Lost

Creek

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.

Figure B7. Locations of wells and streams for which stratigraphic, water-level, water-use, and discharge data are 

available at the Idaho Nuclear Technology and Engineering Center, Idaho National Laboratory, Idaho. 

Click on well, stream gage, or reach number to access information in tables A1 or A2.
Appendix B 163

ID19-0164_GWflow_fig. B8

330

61

60

59

58 57

55

56

54

53

52

51

50

112°57' 112°56'

43°

33'

43°

32'

Central

Facilities

Area

56

EXPLANATION

Well and number that identifies 

the well in appendix table A1

0 0.25 0.5 Mile

0 0.25 0.5 Kilometer

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.

Figure B8. Locations of wells and streams for which stratigraphic, water-level, water-use, and discharge data are 

available at the Central Facilities Area, Idaho National Laboratory, Idaho.

Click on well, stream gage, or reach number to access information in tables A1 or A2.
164 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

ID19-0164_GWflow_fig. B9

346

202 82 81

77

30

30

20

19 18

17

16

15

14

13

12

112°40' 112°39'

43°

36'

43°

35'

Materials

and Fuels

Complex

0 0.25 0.5 Mile

0 0.25 0.5 Kilometer

EXPLANATION

Well and number that identifies 

the well in appendix table A1

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.

Figure B9. Locations of wells and streams for which stratigraphic, water-level, water-use, and discharge data 

are available at the Materials and Fuels Complex, Idaho National Laboratory, Idaho.

Click on well, stream gage, or reach number to access information in tables A1 or A2.
Appendix C 165

Appendix C. Average Streamflow and Infiltration Used for 

Steady-State and Transient Models of Groundwater Flow, 

Idaho National Laboratory and Vicinity, Idaho
166 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Table C1. Average streamflow and infiltration for 1966–80, 1981–95, and 1953–68 used for steady-state and transient models of groundwater flow, Idaho National Laboratory and vicinity, Idaho. [Values are in cubic feet per second. Map No.: Identifier corresponding to a streamflow-gaging station or stream reach on maps located in appendix B figures and as a cross reference with data in other appendixes. Names of stations and reaches are given in table A2 and include the Big Lost River streamflow-gaging stations located near Arco (501), at the inlet to spreading area A (502), at the outlet of spreading area A (503), downstream of the diversion dam used to divert flow into spreading area A (504), at the Lincoln Boulevard bridge near the INTEC (505), and above the Big Lost River Sinks (506). Reaches are located between the model boundary and streamflow-gaging station 501 (600), between streamflow-gaging stations 501 and 504 (601), within spreading area A through D (602–605), between streamflow-gaging stations 504 and 505 (606), between streamflow-gaging station 505 and the Big Lost River Sinks (607), within the Big Lost River Sinks (608), and within Big Lost River Playas 1, 2 (609), and 3 (610). Annual transient stress periods are January through April, May through August, and September through December. Abbreviations: I, infiltration; Q, discharge; INL, Idaho National Laboratory] Year Model boundary to INL diversion INL spreading areas INL diversion to Lincoln Blvd Lincoln Blvd to Playa 3

I Q I Q I Q I I I Q I Q I Q I I I

600 501 601 502 602 503 603 604 605 504 606 505 607 506 608 609 610

Average streamflow and infiltration recharge of 1966-80 for Big Lost River unadjusted for evaporation and used in steady state model

1966 70.29 12.93 45.26 6.58 38.69 29.02 9.67 0.00 12.10 7.040 5.05 5.06 0.00 0.00 0.00 0.00

1967 232.55 15.82 108.22 13.42 94.79 71.09 23.7 .00 108.52 21.810 86.71 15.07 71.64 44.68 26.96 .00

1968 88.72 18.95 34.61 13.28 21.33 17.17 4.17 .00 35.15 12.860 22.29 13.46 8.84 8.84 .00 .00

1969 342.62 17.25 145.31 20.00 125.30 95.42 29.89 .00 180.90 19.460 161.44 24.23 137.21 58.08 23.59 55.54

1970 134.82 13.64 35.38 15.25 20.13 16.09 4.04 .00 85.68 13.750 71.93 17.05 54.87 40.04 14.84 .00

1971 256.21 20.54 65.90 20.00 45.90 36.1 9.79 .00 169.77 18.440 151.33 23.67 127.66 86.52 17.52 23.62

1972 96.47 17.29 35.64 13.28 22.37 17.15 5.21 .00 43.53 17.040 26.49 15.73 10.76 10.76 .00 .00

1973 54.81 20.12 23.43 8.53 14.89 11.17 3.72 .00 11.27 6.800 4.47 4.47 .00 .00 .00 .00

1974 157.80 17.06 44.72 20.00 24.72 19.41 5.31 .00 96.03 24.780 71.25 19.23 52.01 37.29 14.72 .00

1975 199.11 14.54 63.75 20.00 43.75 34.29 9.45 .00 120.82 21.010 99.81 19.94 79.87 48.42 31.45 .00

1976 89.00 13.13 51.62 13.28 38.34 28.76 9.59 .00 24.26 14.050 10.21 10.21 .00 .00 .00 .00

1977 16.66 8.49 4.51 4.51 .00 .00 .00 .00 3.66 3.660 .00 .00 .00 .00 .00 .00

1978 10.24 10.24 .00 .00 .00 .00 .00 .00 .00 .000 .00 .00 .00 .00 .00 .00

1979 11.42 10.79 .00 .00 .00 .00 .00 .00 .64 .640 .00 .00 .00 .00 .00 .00

1980 32.70 17.62 .04 .04 .00 .00 .00 .00 15.04 13.470 1.57 1.57 .00 .00 .00 .00

Simulated 6.56 119.53 15.23 43.88 12.05 30.99 23.78 7.21 0.00 60.47 12.99 47.48 11.31 36.17 22.30 8.60 5.27
Appendix C 167

Table C1. Average streamflow and infiltration for 1966–80, 1981–95, and 1953–68 used for steady-state and transient models of groundwater flow, Idaho National Laboratory and vicinity, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier corresponding to a streamflow-gaging station or stream reach on maps located in appendix B figures and as a cross reference with data in other appendixes. Names of stations and reaches are given in table A2 and include the Big Lost River streamflow-gaging stations located near Arco (501), at the inlet to spreading area A (502), at the outlet of spreading area A (503), downstream of the diversion dam used to divert flow into spreading area A (504), at the Lincoln Boulevard bridge near the INTEC (505), and above the Big Lost River Sinks (506). 

Reaches are located between the model boundary and streamflow-gaging station 501 (600), between streamflow-gaging stations 501 and 504 (601), within spreading area A through D (602–605), between streamflow-gaging stations 504 and 505 (606), between streamflow-gaging station 505 and the Big Lost River Sinks (607), within the Big Lost River Sinks (608), and within Big Lost River Playas 1, 2 (609), and 3 (610). Annual transient stress periods are January through April, May through August, and September through December. Abbreviations: I, infiltration; Q, discharge; INL, Idaho National Laboratory]

Year and 

stress 

period

Model boundary to INL diversion INL spreading areas INL diversion to Lincoln Blvd Lincoln Blvd to Playa 3

I Q I Q I Q I I I Q I Q I Q I I I

600 501 601 502 602 503 603 604 605 504 606 505 607 506 608 609 610

Streamflow and infiltration of 1980-95 for Big Lost River adjusted for evaporation and used in transient model

1980

1 6.37 14.63 10.55 24.73 7.49 0.00 12.64 10.94 20.19 7.94 4.93

1981 6.45 42.51 14.03 1.23 .88 0.31 .30 .00 .00 26.88 7.44 19.27 6.05 13.04 11.68 .00 .00

2 6.51 18.01 1.34 .46 .00 .00 3.42 5.34 .00 .00 .00

3 6.34 12.99 1.31 .46 .00 .00 18.75 12.74 34.66 .00 .00

4 6.49 11.16 .00 .00 .00 .00 .00 .00 .00 .00 .00

1982 6.42 218.12 26.93 64.32 14.80 48.79 37.44 10.69 .00 126.52 13.77 112.55 15.43 97.03 55.25 18.19 16.99

5 6.50 18.06 1.24 1.90 .00 .00 4.36 11.98 12.41 .00 .00

6 6.30 35.05 23.36 95.80 31.73 .00 26.90 19.20 75.49 46.03 50.42

7 6.47 27.47 19.50 13.57 .00 .00 9.78 15.01 76.97 8.02 .00

1983 6.39 477.91 27.04 291.28 33.78 256.21 190.68 63.32 .00 159.26 23.76 135.31 16.19 118.91 63.15 20.72 27.84

8 6.47 19.14 24.48 89.73 29.85 .00 12.02 13.45 47.50 .00 .00

9 6.28 18.57 37.68 250.27 82.95 .00 34.12 20.79 83.81 52.06 82.61

10 6.41 43.36 38.99 229.89 76.44 .00 24.86 14.26 57.73 9.51 .00

1984 6.38 488.42 28.45 381.62 36.45 343.65 255.54 84.82 .00 78.01 16.73 61.08 13.29 47.57 41.23 3.59 .00

11 6.44 54.48 39.17 206.65 68.74 .00 11.76 11.95 11.71 .00 .00

12 6.27 18.58 46.91 399.41 132.32 .00 23.65 13.41 49.24 .00 .00

13 6.44 12.59 23.20 158.98 52.86 .00 14.67 14.51 62.42 10.76 .00

1985 6.43 120.76 20.24 39.38 7.21 32.00 23.94 7.91 .00 60.76 11.41 49.13 12.81 36.09 30.87 3.57 .00

14 6.48 37.29 18.65 72.35 24.07 .00 12.27 12.19 17.39 .00 .00

15 6.34 5.58 .23 .13 .00 .00 6.24 11.73 12.74 .00 .00

16 6.48 18.26 3.00 .34 .00 .00 15.79 14.51 62.41 10.68 .00
168 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Table C1. Average streamflow and infiltration for 1966–80, 1981–95, and 1953–68 used for steady-state and transient models of groundwater flow, Idaho National Laboratory and vicinity, Idaho.—Continued [Values are in cubic feet per second. Map No.: Identifier corresponding to a streamflow-gaging station or stream reach on maps located in appendix B figures and as a cross reference with data in other appendixes. Names of stations and reaches are given in table A2 and include the Big Lost River streamflow-gaging stations located near Arco (501), at the inlet to spreading area A (502), at the outlet of spreading area A (503), downstream of the diversion dam used to divert flow into spreading area A (504), at the Lincoln Boulevard bridge near the INTEC (505), and above the Big Lost River Sinks (506). Reaches are located between the model boundary and streamflow-gaging station 501 (600), between streamflow-gaging stations 501 and 504 (601), within spreading area A through D (602–605), between streamflow-gaging stations 504 and 505 (606), between streamflow-gaging station 505 and the Big Lost River Sinks (607), within the Big Lost River Sinks (608), and within Big Lost River Playas 1, 2 (609), and 3 (610). Annual transient stress periods are January through April, May through August, and September through December. Abbreviations: I, infiltration; Q, discharge; INL, Idaho National Laboratory] Year and stress period Model boundary to INL diversion INL spreading areas INL diversion to Lincoln Blvd Lincoln Blvd to Playa 3

I Q I Q I Q I I I Q I Q I Q I I I

600 501 601 502 602 503 603 604 605 504 606 505 607 506 608 609 610

Streamflow and infiltration of 1980-95 for Big Lost River adjusted for evaporation and used in transient model—Continued

1986 6.43 204.94 23.07 59.09 16.79 41.52 32.14 8.84 0.00 122.42 22.44 99.78 17.35 82.21 48.92 20.17 7.79

17 6.49 26.82 4.59 1.83 .00 .00 28.42 12.48 24.51 .00 .00

18 6.32 21.90 24.68 79.19 26.23 .00 30.21 16.98 68.76 46.11 15.38

19 6.47 20.57 20.83 14.52 .00 .00 8.74 22.52 52.92 13.85 7.79

1987 6.45 29.21 11.49 10.27 7.36 2.76 2.75 .00 .00 7.10 5.52 1.41 1.37 .00 .00 .00 .00

20 6.50 15.65 22.39 8.35 .00 .00 15.02 4.17 .00 .00 .00

21 6.37 6.52 .00 .00 .00 .00 1.74 .00 .00 .00 .00

22 6.49 12.40 .00 .00 .00 .00 .00 .00 .00 .00 .00

1988 4.28 2.91 2.58 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

23 6.51 7.53 .00 .00 .00 .00 .00 .00 .00 .00 .00

24 6.32 .28 .00 .00 .00 .00 .00 .00 .00 .00 .00

25 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

1989 .00 0 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

26 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

27 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

28 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

1990 .00 0 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

29 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

30 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

31 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

1991 .00 0 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

32 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

33 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

34 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00
Appendix C 169

Table C1. Average streamflow and infiltration for 1966–80, 1981–95, and 1953–68 used for steady-state and transient models of groundwater flow, Idaho National Laboratory and vicinity, Idaho. —Continued[Values are in cubic feet per second. Map No.: Identifier corresponding to a streamflow-gaging station or stream reach on maps located in appendix B figures and as a cross reference with data in other appendixes. Names of stations and reaches are given in table A2 and include the Big Lost River streamflow-gaging stations located near Arco (501), at the inlet to spreading area A (502), at the outlet of spreading area A (503), downstream of the diversion dam used to divert flow into spreading area A (504), at the Lincoln Boulevard bridge near the INTEC (505), and above the Big Lost River Sinks (506). 

Reaches are located between the model boundary and streamflow-gaging station 501 (600), between streamflow-gaging stations 501 and 504 (601), within spreading area A through D (602–605), between streamflow-gaging stations 504 and 505 (606), between streamflow-gaging station 505 and the Big Lost River Sinks (607), within the Big Lost River Sinks (608), and within Big Lost River Playas 1, 2 (609), and 3 (610). Annual transient stress periods are January through April, May through August, and September through December. Abbreviations: I, infiltration; Q, discharge; INL, Idaho National Laboratory]

Year and 

stress 

period

Model boundary to INL diversion INL spreading areas INL diversion to Lincoln Blvd Lincoln Blvd to Playa 3

I Q I Q I Q I I I Q I Q I Q I I I

600 501 601 502 602 503 603 604 605 504 606 505 607 506 608 609 610

Streamflow and infiltration of 1980-95 for Big Lost River adjusted for evaporation and used in transient model—Continued

1992 0.00 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

35 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

36 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

37 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

1993 2.14 14.69 3.72 .22 .20 .00 .00 .00 .00 10.53 3.35 7.05 3.89 3.03 2.71 .00 .00

38 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

39 6.35 11.05 .60 .00 .00 .00 9.93 11.53 8.04 .00 .00

40 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

1994 .00 0 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

41 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

42 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

43 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

1995 4.29 125.87 11.89 50.14 15.15 33.84 20.02 6.62 6.63 63.54 9.10 54.27 5.74 48.39 22.99 21.08 .00

44 .00 .00 .00 .00 .00 .00 .00 .05 .00 .00 .00

45 6.30 13.59 44.97 59.42 19.64 19.68 17.13 16.98 68.23 62.55 .00

46 6.49 21.86 .00 .00 .00 .00 9.96 .00 .00 .00 .00

Streamflow and infiltration of 1953-68 for Big Lost River unadjusted for evaporation and used in transient particle path analysis

1953 75.44 0.00 0.00 59.49 43.61 25.39

1 6.56 15.95 0.00 0.00 0.00 0.00 15.88 18.22 17.26 8.13 0.00

1954 6.56 32.97 15.95 .00 .00 .00 .00 .00 .00 17.02 10.22 6.80 6.10 .70 .70 .00 .00

2 6.56 15.95 .00 .00 .00 .00 15.88 18.55 2.13 .00 .00

3 6.56 15.95 .00 .00 .00 .00 2.62 .00 .00 .00 .00

4 6.56 15.95 .00 .00 .00 .00 12.32 .00 .00 .00 .00
170 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Year and stress period Model boundary to INL diversion INL spreading areas INL diversion to Lincoln Blvd Lincoln Blvd to Playa 3

I Q I Q I Q I I I Q I Q I Q I I I

600 501 601 502 602 503 603 604 605 504 606 505 607 506 608 609 610

Streamflow and infiltration of 1953-68 for Big Lost River unadjusted for evaporation and used in transient particle path analysis

1955 6.56 15.27 13.09 0.00 0.00 0.00 0.00 0.00 0.00 2.19 2.19 0.00 0.00 0.00 0.00 0.00 0.00

5 6.56 15.95 .00 .00 .00 .00 1.98 .00 .00 .00 .00

6 6.56 7.45 .00 .00 .00 .00 .00 .00 .00 .00 .00

7 6.56 15.95 .00 .00 .00 .00 4.60 .00 .00 .00 .00

1956 6.56 93.06 15.95 .00 .00 .00 .00 .00 .00 77.11 15.88 61.23 18.55 42.68 42.68 .00 .00

8 6.56 15.95 .00 .00 .00 .00 15.88 18.55 11.10 .00 .00

9 6.56 15.95 .00 .00 .00 .00 15.88 18.55 115.14 .00 .00

10 6.56 15.95 .00 .00 .00 .00 15.88 18.55 .96 .00 .00

1957 6.56 99.81 15.95 .00 .00 .00 .00 .00 .00 83.86 15.88 67.98 14.55 53.43 53.43 .00 .00

11 6.56 15.95 .00 .00 .00 .00 15.88 6.37 .00 .00 .00

12 6.56 15.95 .00 .00 .00 .00 15.88 18.55 127.85 .00 .00

13 6.56 15.95 .00 .00 .00 .00 15.88 18.55 30.96 .00 .00

1958 6.56 196.4 15.95 .00 .00 .00 .00 .00 .00 180.45 15.88 164.57 18.55 146.02 52.51 15.17 78.33

14 6.56 15.95 .00 .00 .00 .00 15.88 18.55 52.51 4.18 .00

15 6.56 15.95 .00 .00 .00 .00 15.88 18.55 52.51 20.56 214.15

16 6.56 15.95 .00 .00 .00 .00 15.88 18.55 52.51 20.56 18.45

1959 6.56 32.73 12.81 .00 .00 .00 .00 .00 .00 19.91 5.22 14.69 6.10 8.59 8.59 .00 .00

17 6.56 15.95 .00 .00 .00 .00 15.88 18.55 26.14 .00 .00

18 6.56 9.71 .00 .00 .00 .00 .00 .00 .00 .00 .00

19 6.56 12.86 .00 .00 .00 .00 .00 .00 .00 .00 .00

1960 6.58 3.64 3.64 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

20 6.56 10.65 .00 .00 .00 .00 .00 .00 .00 .00 .00

21 6.56 .30 .00 .00 .00 .00 .00 .00 .00 .00 .00

22 6.56 .02 .00 .00 .00 .00 .00 .00 .00 .00 .00

Table C1. Average streamflow and infiltration for 1966–80, 1981–95, and 1953–68 used for steady-state and transient models of groundwater flow, Idaho National Laboratory and vicinity, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier corresponding to a streamflow-gaging station or stream reach on maps located in appendix B figures and as a cross reference with data in other appendixes. Names of stations and reaches are given in table A2 and include the Big Lost River streamflow-gaging stations located near Arco (501), at the inlet to spreading area A (502), at the outlet of spreading area A (503), downstream of the diversion dam used to divert flow into spreading area A (504), at the Lincoln Boulevard bridge near the INTEC (505), and above the Big Lost River Sinks (506). 

Reaches are located between the model boundary and streamflow-gaging station 501 (600), between streamflow-gaging stations 501 and 504 (601), within spreading area A through D (602–605), between streamflow-gaging stations 504 and 505 (606), between streamflow-gaging station 505 and the Big Lost River Sinks (607), within the Big Lost River Sinks (608), and within Big Lost River Playas 1, 2 (609), and 3 (610). Annual transient stress periods are January through April, May through August, and September through December. Abbreviations: I, infiltration; Q, discharge; INL, Idaho National Laboratory]
Appendix C 171

Year and 

stress 

period

Model boundary to INL diversion INL spreading areas INL diversion to Lincoln Blvd Lincoln Blvd to Playa 3

I Q I Q I Q I I I Q I Q I Q I I I

600 501 601 502 602 503 603 604 605 504 606 505 607 506 608 609 610

Streamflow and infiltration of 1953-68 for Big Lost River unadjusted for evaporation and used in transient particle path analysis—Continued

1961 2.16 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

23 6.56 .03 .00 .00 .00 .00 .00 .00 .00 .00 .00

24 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

25 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

1962 4.4 20.11 10.71 .00 .00 .00 .00 .00 .00 9.40 6.67 2.73 2.73 .00 .00 .00 .00

26 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00

27 6.56 15.95 .00 .00 .00 .00 4.05 .00 .00 .00 .00

28 6.56 15.95 .00 .00 .00 .00 15.88 8.17 .00 .00 .00

1963 6.56 91.89 15.95 .00 .00 .00 .00 .00 .00 75.94 15.88 60.06 18.55 41.51 41.51 .00 .00

29 6.56 15.95 .00 .00 .00 .00 15.88 18.55 9.62 .00 .00

30 6.56 15.95 .00 .00 .00 .00 15.88 18.55 59.62 .00 .00

31 6.56 15.95 .00 .00 .00 .00 15.88 18.55 54.62 .00 .00

1964 6.58 95.37 15.99 .00 .00 .00 .00 .00 .00 79.38 15.92 63.45 18.60 44.85 44.85 .00 .00

32 6.56 15.95 .00 .00 .00 .00 15.88 18.55 19.62 .00 .00

33 6.56 15.95 .00 .00 .00 .00 15.88 18.55 59.62 .00 .00

34 6.56 15.95 .00 .00 .00 .00 15.88 18.55 54.62 .00 .00

1965 6.56 343.67 15.95 158.94 13.42 145.52 109.14 36.38 .00 168.78 15.88 152.90 18.55 134.35 29.38 6.93 98.03

35 6.56 15.95 .00 .00 .00 .00 15.88 18.55 20.06 .00 .00

36 6.56 15.95 20.00 177.14 59.05 .00 15.88 18.55 52.51 20.56 290.91

37 6.56 15.95 20.00 147.93 49.31 .00 15.88 18.55 15.24 .00 .00

1966 6.54 70.1 12.89 45.14 6.56 38.58 28.94 9.65 .00 12.07 7.02 5.04 5.04 .00 .00 .00 .00

38 6.56 19.34 20.00 88.26 29.42 .00 12.31 15.38 .00 .00 .00

39 6.56 11.38 .00 .00 .00 .00 8.89 .00 .00 .00 .00

40 6.56 8.17 .00 .00 .00 .00 .00 .00 .00 .00 .00

Table C1. Average streamflow and infiltration for 1966–80, 1981–95, and 1953–68 used for steady-state and transient models of groundwater flow, Idaho National Laboratory and vicinity, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier corresponding to a streamflow-gaging station or stream reach on maps located in appendix B figures and as a cross reference with data in other appendixes. Names of stations and reaches are given in table A2 and include the Big Lost River streamflow-gaging stations located near Arco (501), at the inlet to spreading area A (502), at the outlet of spreading area A (503), downstream of the diversion dam used to divert flow into spreading area A (504), at the Lincoln Boulevard bridge near the INTEC (505), and above the Big Lost River Sinks (506). 

Reaches are located between the model boundary and streamflow-gaging station 501 (600), between streamflow-gaging stations 501 and 504 (601), within spreading area A through D (602–605), between streamflow-gaging stations 504 and 505 (606), between streamflow-gaging station 505 and the Big Lost River Sinks (607), within the Big Lost River Sinks (608), and within Big Lost River Playas 1, 2 (609), and 3 (610). Annual transient stress periods are January through April, May through August, and September through December. Abbreviations: I, infiltration; Q, discharge; INL, Idaho National Laboratory]
172 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Year and stress period Model boundary to INL diversion INL spreading areas INL diversion to Lincoln Blvd Lincoln Blvd to Playa 3

I Q I Q I Q I I I Q I Q I Q I I I

600 501 601 502 602 503 603 604 605 504 606 505 607 506 608 609 610

Streamflow and infiltration of 1953-68 for Big Lost River unadjusted for evaporation and used in transient particle path analysis—Continued

1967 6.56 232.55 15.81 108.22 13.42 94.79 71.10 23.70 0.00 108.52 21.81 86.71 15.07 71.64 44.68 26.96 0.00

41 6.56 8.39 .00 .00 .00 .00 .00 .00 .00 .00 .00

42 6.56 19.66 20.00 172.85 57.62 .00 45.44 25.51 78.87 80.01 .00

43 6.56 19.24 20.00 38.44 12.81 .00 19.43 19.36 54.16 .00 .00

1968 6.58 88.96 19.00 34.71 13.32 21.39 17.22 4.18 .00 35.25 12.89 22.35 13.49 8.86 8.86 .00 .00

44 6.56 19.33 20.00 14.13 .00 .00 11.71 16.59 7.03 .00 .00

45 6.56 17.48 .00 .00 .00 .00 8.41 6.53 .00 .00 .00

46 6.56 20.06 20.00 37.49 12.50 .00 18.48 17.33 19.53 .00 .00

Table C1. Average streamflow and infiltration for 1966–80, 1981–95, and 1953–68 used for steady-state and transient models of groundwater flow, Idaho National Laboratory and vicinity, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier corresponding to a streamflow-gaging station or stream reach on maps located in appendix B figures and as a cross reference with data in other appendixes. Names of stations and reaches are given in table A2 and include the Big Lost River streamflow-gaging stations located near Arco (501), at the inlet to spreading area A (502), at the outlet of spreading area A (503), downstream of the diversion dam used to divert flow into spreading area A (504), at the Lincoln Boulevard bridge near the INTEC (505), and above the Big Lost River Sinks (506). 

Reaches are located between the model boundary and streamflow-gaging station 501 (600), between streamflow-gaging stations 501 and 504 (601), within spreading area A through D (602–605), between streamflow-gaging stations 504 and 505 (606), between streamflow-gaging station 505 and the Big Lost River Sinks (607), within the Big Lost River Sinks (608), and within Big Lost River Playas 1, 2 (609), and 3 (610). Annual transient stress periods are January through April, May through August, and September through December. Abbreviations: I, infiltration; Q, discharge; INL, Idaho National Laboratory]
Appendix D 173

Appendix D. Industrial Wastewater Disposal to Model 

Layer 1 Used for Steady-State and Transient Models of 

Groundwater Flow, Idaho National Laboratory, Idaho
174 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Table D1. Industrial wastewater disposal to model layer 1 used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho. [Values are in cubic feet per second. Map No.: Identifier corresponding to locations of production wells on maps shown in appendix B figures and as a cross reference with data in other appendixes. Locations of infiltration from disposal of industrial waste to ponds and ditches or landscape irrigation at facilities and facility names are also shown on figure 18. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Abbreviations: ARA, Army Reactor Area; CFA, Central Facilities Area; EBR I, Experimental Breeder Reactor I; INTEC, Idaho Nuclear Technology and Engineering Center; MFC, Materials and Fuels Complex; NRF, Naval Reactors Facility; PBF, Power Burst Facility; RTC, Reactor Technology Center; RWMC, Radioactive Waste Management Complex; TAN, Test Area North] Stress period Simu- lated year Four month period Map No. corresponding to a nearby production well, facility abbreviation, and corresponding waste disposal type 29 51 80 66 82 131 205 246 191 86 207 24 ARA CFA EBR I INTEC MFC NRF PBF RTC RWMC TAN Waste Waste Waste Infil- tration ponds Sewage Waste to gravel pit Pond Sewage Sewage Waste Waste Chemi- cal waste Cold waste Irri- gation Sewage Warm waste Waste LOFT dis- posal Waste TAN+ LOFT dispo- sal WRRTF sewage

1 11980 0.144 0.245 0.001 0.000 0.059 0.000 0.219 0.028 0.076 0.615 0.072 0.049 0.000 0.107 0.035 0.241 0.016 0.624 0.067 0.001 0.003

2 1981 (a) .166 .173 .001 .000 .048 .000 .193 .018 .072 .182 .018 .036 .000 .013 .028 .210 .018 .544 .057 .000 .002

3 (b) .163 .555 .001 .000 .057 .000 .266 .024 .067 .607 .039 .039 .000 .113 .026 .233 .037 .425 .079 .001 .003

4 (c) .132 .240 .001 .000 .057 .000 .181 .023 .062 .389 .043 .045 .000 .029 .019 .237 .055 .478 .064 .002 .004

5 1982 (a) .113 .224 .001 .000 .065 .000 .192 .029 .056 .884 .075 .048 .653 .019 .021 .287 .050 .346 .064 .001 .002

6 (b) .135 .481 .001 .000 .059 .000 .210 .024 .070 .444 .101 .034 .961 .181 .021 .189 .028 2.823 .081 .001 .002

7 (c) .140 .107 .001 .980 .057 1.215 .093 .022 .077 .352 .072 .030 1.120 .039 .023 .160 .036 .327 .063 .001 .002

8 1983 (a) .122 .023 .001 .000 .052 .000 .121 .025 .073 .186 .085 .031 1.048 .016 .023 .116 .014 .391 .058 .002 .001

9 (b) .129 .424 .001 .000 .039 .000 .161 .017 .105 .685 .101 .026 1.004 .124 .033 .122 .012 .555 .096 .001 .001

10 (c) .111 .286 .001 .000 .029 .000 .221 .016 .075 .476 .066 .028 1.002 .047 .023 .134 .005 .425 .084 .001 .001

11 1984 (a) .081 .206 .001 1.112 .030 .000 .158 .016 .083 .474 .068 .025 1.015 .019 .020 .087 .009 .314 .076 .001 .001

12 (b) .059 .409 .001 2.513 .031 .000 .195 .018 .140 .548 .110 .022 1.039 .146 .029 .070 .015 .118 .090 .001 .002

13 (c) .061 .261 .000 2.028 .029 .000 .245 .022 .103 .611 .069 .027 1.105 .066 .027 .039 .009 .728 .078 .001 .001

14 1985 (a) .059 .228 .001 1.844 .032 .000 .214 .035 .112 .356 .047 .025 .848 .000 .027 .023 .026 .212 .085 .001 .076

15 (b) .075 .563 .001 1.587 .028 .000 .290 .028 .086 .724 .054 .026 .963 .132 .036 .094 .034 .807 .079 .001 .047

16 (c) .068 .154 .001 2.457 .023 .000 .250 .037 .104 .077 .037 .025 1.015 .038 .027 .084 .025 .327 .076 .001 .030

17 1986 (a) .044 .128 .001 2.054 .034 .000 .177 .063 .154 .120 .049 .029 1.534 .025 .035 .118 .007 .087 .091 .001 .020

18 (b) .083 .466 .001 2.453 .031 .000 .300 .066 .117 .524 .030 .025 1.120 .118 .042 .108 .001 .098 .149 .000 .023

19 (c) .129 .173 .000 2.424 .030 .000 .225 .061 .111 .412 .026 .028 .816 .062 .030 .092 .001 .064 .131 .001 .023

20 1987 (a) .112 .113 .000 2.553 .040 .000 .198 .058 .138 .340 .008 .027 .756 .080 .025 .083 .001 .073 .116 .002 .013

21 (b) .167 .401 .000 2.619 .036 .000 .284 .014 .118 .315 .056 .023 .788 .215 .034 .088 .001 .069 .155 .000 .009

22 (c) .169 .142 .000 2.451 .037 .000 .285 .011 .141 .046 .051 .020 .723 .071 .027 .069 .001 .059 .120 .000 .010

23 1988 (a) .077 .090 .000 2.556 .043 .000 .207 .011 .198 .041 .054 .023 1.190 .052 .026 .080 .001 .017 .120 .000 .009

24 (b) .050 .593 .000 2.468 .036 .000 .234 .012 .231 .256 .079 .016 .829 .425 .036 .074 .001 .000 .168 .000 .008

25 (c) .009 .171 .000 2.161 .037 .000 .212 .026 .168 .115 .045 .014 .831 .240 .031 .078 .001 .000 .167 .000 .019
Appendix D 175

Table D1. Industrial wastewater disposal to model layer 1 used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier corresponding to locations of production wells on maps shown in appendix B figures and as a cross reference with data in other appendixes. Locations of infiltration from disposal of industrial waste to ponds and ditches or landscape irrigation at facilities and facility names are also shown on figure 18. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Abbreviations: ARA, Army Reactor Area; CFA, Central Facilities Area; EBR I, Experimental Breeder Reactor I; INTEC, Idaho Nuclear Technology and Engineering Center; MFC, Materials and Fuels Complex; NRF, Naval Reactors Facility; PBF, Power Burst Facility; RTC, Reactor Technology Center; RWMC, Radioactive Waste Management Complex; TAN, Test Area North]

Stress 

period

Simulated 

year

Four 

month 

period

Map No. corresponding to a nearby production well, facility abbreviation, and corresponding waste disposal type

29 51 80 66 82 131 205 246 191 86 207 24

ARA CFA EBR I INTEC MFC NRF PBF RTC RWMC TAN

Waste Waste Waste

Infiltration 

ponds

Sewage

Waste 

to 

gravel 

pit

Pond Sewage Sewage Waste Waste

Chemical 

waste

Cold 

waste

Irrigation Sewage Warm waste Waste LOFT dis- posal Waste TAN+ LOFT dispo- sal WRRTF sewage

26 1989 (a) 0.000 0.138 0.000 1.935 0.044 0.000 0.139 0.021 0.238 0.176 0.013 0.032 1.127 0.100 0.028 0.097 0.001 0.118 0.124 0.000 0.020

27 (b) .000 .647 .000 1.676 .038 .000 .103 .022 .117 .488 .041 .032 1.339 .442 .038 .081 .001 .134 .121 .000 .01928 (c) .000 .199 .000 1.977 .042 .000 .112 .019 .068 .462 .010 .034 1.269 .183 .038 .108 .001 .290 .183 .000 .026

29 1990 (a) .000 .145 .000 2.313 .045 .000 .181 .015 .078 .590 .015 .030 1.006 .012 .034 .076 .001 .098 .087 .000 .01630 (b) .000 .704 .000 2.990 .050 .000 .497 .014 .065 .416 .028 .036 1.173 .516 .044 .092 .001 .115 .127 .000 .011

31 (c) .000 .301 .000 2.606 .049 .000 .213 .011 .047 .227 .031 .029 1.053 .121 .031 .082 .001 .109 .109 .000 .00732 1991 (a) .000 .210 .000 2.194 .050 .000 .208 .018 .060 .331 .013 .034 .964 .000 .037 .112 .001 1.367 .134 .000 .04333 (b) .000 .598 .000 2.376 .042 .000 .161 .011 .062 .762 .045 .042 1.204 .378 .070 .144 .001 .098 .120 .000 .012

34 (c) .000 .304 .000 2.501 .046 .000 .182 .014 .047 .530 .045 .033 .452 .575 .060 .108 .003 .038 .077 .000 .016

35 1992 (a) .000 .247 .000 2.850 .069 .000 .124 .013 .055 .556 .009 .033 .390 .389 .055 .108 .002 .010 .233 .000 .018

36 (b) .000 .761 .000 2.457 .072 .000 .251 .015 .076 .842 .026 .041 .600 .770 .051 .092 .003 .000 .185 .000 .007

37 (c) .000 .259 .000 2.307 .096 .000 .179 .016 .057 .774 .015 .035 .831 .431 .053 .097 .001 .000 .081 .000 .010

38 1993 (a) .000 .179 .000 3.029 .059 .000 .156 .033 .046 .711 .011 .028 .904 .306 .055 .098 .002 .000 .093 .000 .018

39 (b) .000 .622 .000 2.825 .055 .000 .135 .032 .059 .785 .014 .027 1.107 .464 .055 .081 .004 .000 .078 .000 .013

40 (c) .000 .250 .000 2.593 .053 .000 .095 .074 .047 .679 .014 .026 1.165 .142 .062 .041 .006 .000 .125 .000 .004

41 1994 (a) .000 .146 .000 2.551 .081 .000 .067 .053 .049 .547 .014 .027 .922 .085 .068 .029 .002 .000 .111 .000 .006

42 (b) .000 .576 .000 1.701 .196 .000 .130 .018 .063 .583 .026 .024 1.089 .507 .061 .026 .002 .000 .142 .000 .018

43 (c) .000 .234 .000 1.991 .077 .000 .077 .017 .057 .423 .015 .026 .704 .007 .090 .031 .002 .000 .090 .000 .005

44 1995 (a) .000 .500 .000 2.240 .096 .000 .047 .016 .072 .445 .014 .026 .680 .000 .099 .033 .003 .000 .072 .000 .003

45 (b) .000 .596 .000 2.070 .080 .000 .061 .016 .082 .334 .017 .030 .795 .000 .096 .033 .003 .000 .089 .000 .00246 (c) .000 .461 .000 1.570 .067 .000 .060 .013 .074 .208 .014 .025 .678 .000 .089 .028 .005 .000 .071 .000 .002

1 Steady-state stress period.
176 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

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Appendix E 177

Appendix E. Irrigation Well Withdrawals Used for SteadyState and Transient Models of Groundwater Flow, Idaho 

National Laboratory and Vicinity, Idaho
178 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table E1. Irrigation well withdrawals used in the calibration of steady-state and transient models of groundwater flow, Idaho National 

Laboratory and vicinity, Idaho.

[Values are annual total in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference 

with data in other appendixes. Local name: Local well identifier used in this study. Row, Column, and Layer: Model grid coordinates. Negative values are 

withdrawals]

Map No. Local name Row Column Layer 1 Layer 2 Layer 3 Layer 4 Layer 5

2 434556 47 178 -0.596 -0.726 -0.356

3 434647 51 192 -0.217 -.219 -.219 -.099

4 434650 49 188 -.136 -.619

121 ML11 51 194 -.268 -.327 -.160

122 ML12 46 175 -1.199

123 ML13 46 188 -.755

ML21-11 68 266 -.215 -.215 -.022 -.044

ML21-9 66 260 -.146 -.146 -.146 -.293 -0.477

ML23-11 76 264 -.046 -.046 -.002 -.003

ML24-10 78 263 -.102 -.102 -.047 -.005

ML24-11 80 267 -.003 -.003 -.003 -.005

ML25-11a 82 266 -.078 -.078 -.051 -.103

ML25-11b 83 265 -.078 -.078 -.051 -.103

ML26-10a 86 261 -.143 -.036

ML26-10b 86 261 -.143 -.036

ML26-10c 85 264 -.143 -.036

ML26-11a 87 265 -.180 -.176

ML26-11b 88 267 -.180 -.176

ML27-10a 90 264 -.132 -.128

ML27-10b 91 264 -.430 -.128

ML27-11 92 268 -.543 -.529

ML27-12a 89 269 -.164 -.137

ML27-12b 89 269 -.164 -.137

ML27-12c 89 271 -.164 -.137

ML27-13 89 272 -.411 -.101

ML28-12a 94 271 -.336

ML28-12b 95 271 -.336

ML28-13 96 275 -.101

ML28-15 96 280 -.335 -.082

ML28-17 96 292 -.512

ML29-14a 98 277 -.263 -.065

ML29-14b 98 278 -.263 -.065

ML29-15a 100 281 -.132 -.106

ML29-15b 98 283 -.430 -.106

ML29-15c 97 283 -.430 -.106

ML29-16 99 287 -.173 -.043

ML29-17a 97 289 -.258 -.038

ML29-17b 99 290 -.258 -.038

ML29-18a 97 295 -.502 -.019

ML29-18b 99 296 -.502 -.019
Appendix E 179

Table E1. Irrigation well withdrawals used in the calibration of steady-state and transient models of groundwater flow, Idaho National 

Laboratory and vicinity, Idaho.—Continued

[Values are annual total in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference 

with data in other appendixes. Local name: Local well identifier used in this study. Row, Column, and Layer: Model grid coordinates. Negative values are 

withdrawals]

Map No. Local name Row Column Layer 1 Layer 2 Layer 3 Layer 4 Layer 5

ML29-19 101 299 -0.553

ML30-15a 102 280 -.699 -0.063

ML30-15b 103 283 -.699 -.063

ML30-16a 101 285 -.669 -.265 -0.033 -0.065

ML30-16b 102 286 -.669 -.265 -.033 -.065

ML30-16c 103 287 -.669 -.265 -.033 -.065

ML30-17a 102 289 -.257 -.084

ML30-17b 101 291 -.257 -.084

ML30-17c 104 292 -.257 -.084

ML30-18a 102 293 -.283 -.042

ML30-18b 104 296 -.283 -.042

ML30-19a 102 296 -.511

ML30-19b 102 297 -.511

ML31-16 105 284 -1.201 -.264

ML31-17a 106 290 -.374 -.055

ML31-17b 106 292 -.374 -.055

ML32-17 111 288 -.690

ML32-18 110 295 -1.605 -.161

MontM 41 265 -.482 -1.124 -.126 -.252

MontN 38 265 -.340 -.303

MontS 42 263 -.009 -.009 -.123 -.247

RenoM 12 273 -.880

RenoN 12 279 -.359 -.127

RenoPoint 12 275 -.485

RenoS 12 267 -.993
180 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

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Appendix F 181

Appendix F. Industrial Well Withdrawals or Injections Used 

for Steady-State and Transient Models of Groundwater 

Flow, Idaho National Laboratory, Idaho
182 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho. [Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration] Stress period Simulated year Four month period Map No. and local name corresponding to well 24 28 29 34 50 51 66 67 68 69 80 81 82 86 87 88 89 ANP 8 ARA 2 ARA 3 BADGING FACILITY CFA 1 CFA 2 CPP 1 CPP 2 CPP 3 CPP 4 EBR 1 EBR 2-1 EBR II-2 FET1 FET2 FET DISP3 FIRE STA2 Layer 1

1 19801 -0.140 -0.042 0.000 -0.021 -0.169 -0.636 -0.380 1.389 -0.024 -0.003 -0.300 -0.270 -0.324 -0.155 0.091 -0.017

2 1981 (a) -.123 -.046 .000 .000 -.095 -.840 -.502 1.874 -.019 -.002 -.212 -.191 -.290 -.084 .000 -.028

3 (b) -.095 -.055 .000 -.058 -.229 -.769 -.459 1.705 -.023 -.003 -.387 -.348 -.129 -.191 .000 -.006

4 (c) -.168 -.049 .000 -.009 -.131 -.897 -.536 2.412 -.023 -.002 -.317 -.285 -.155 -.155 .000 -.009

5 1982 (a) -.098 -.040 .000 -.005 -.093 -.930 -.555 2.517 -.026 -.001 -.218 -.196 -.201 -.092 .000 -.010

6 (b) -.063 -.047 .000 -.171 -.142 -.796 -.475 2.150 -.024 -.002 -.348 -.313 -.237 -1.170 .000 -.005

7 (c) -.061 -.051 .000 -.188 -.024 -.811 -.484 .000 -.023 -.001 -.188 -.169 -.191 -.139 .000 -.005

8 1983 (a) -.062 -.046 .000 -.004 -.103 -.729 -.435 1.973 -.021 .000 -.219 -.198 -.076 -.169 .000 -.010

9 (b) -.062 -.046 .000 -.061 -.223 -.950 -.567 2.598 -.016 .000 -.293 -.264 -.233 -.132 .000 -.003

10 (c) -.105 -.048 .000 -.059 -.104 -.853 -.509 2.339 -.012 -.001 -.283 -.254 -.050 -.186 .000 -.003

11 1984 (a) -.150 -.029 .000 -.090 -.055 -.889 -.531 1.363 -.012 .000 -.202 -.181 -.037 -.119 .000 -.003

12 (b) -.193 -.010 .000 -.206 -.099 -.905 -.541 .003 -.013 -.002 -.339 -.305 -.101 -.009 .000 -.002

13 (c) -.080 -.016 .000 -.136 -.063 -.730 -.436 .000 -.012 -.001 -.320 -.288 -.500 -.072 .000 -.033

14 1985 (a) -.076 -.014 .000 -.096 -.058 -.664 -.397 .000 -.013 -.005 -.284 -.255 -.199 -.061 .000 -.034

15 (b) -.047 -.008 .000 -.278 -.125 -.715 -.427 .000 -.011 -.003 -.400 -.360 -.470 -.128 .000 -.001

16 (c) -.030 -.014 .000 -.091 -.069 -.888 -.530 .000 -.009 -.001 -.334 -.300 -.207 -.106 .000 -.003

17 1986 (a) -.020 -.008 .000 -.079 -.054 -.877 -.524 .000 -.014 .000 -.256 -.231 -.131 -.070 .000 -.003

18 (b) -.023 -.008 .000 -.195 -.130 -.883 -.527 .000 -.012 .000 -.425 -.383 -.084 -.043 .000 -.002

19 (c) -.023 -.017 .000 -.127 -.063 -.873 -.522 .000 -.012 .000 -.348 -.314 -.083 -.049 .000 -.004

20 1987 (a) -.013 -.011 .000 -.081 -.047 -.919 -.549 .000 -.016 .000 -.316 -.284 -.066 -.054 .000 -.003

21 (b) -.009 -.014 .000 -.234 -.079 -.943 -.563 .000 -.015 .000 -.418 -.377 -.084 -.046 .000 -.001

22 (c) -.010 -.017 .000 -.132 -.058 -.882 -.527 .000 -.015 .000 -.405 -.365 -.091 -.055 .000 -.019

23 1988 (a) -.009 -.014 .000 -.001 -.111 -.920 -.550 .000 -.017 .000 -.296 -.266 -.070 -.041 .000 -.017

24 (b) -.008 -.029 .000 -.060 -.324 -.888 -.531 .000 -.015 .000 -.454 -.409 .000 .000 .000 -.008

25 (c) -.019 -.008 .000 -.018 -.139 -.778 -.465 .000 -.015 .000 -.405 -.364 .000 .000 .000 -.022
Appendix F 183

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]

Stress 

period

Simulated 

year

Four 

month 

period

Map No. and local name corresponding to well

24 28 29 34 50 51 66 67 68 69 80 81 82 86 87 88 89

ANP 8 ARA 2 ARA 3 BADGING FACILITY CFA 1 CFA 2 CPP 1 CPP 2 CPP 3 CPP 4 EBR 1 EBR 2-1 EBR II-2 FET1 FET2 FET DISP3 FIRE STA2

Layer 1—Continued

26 1989 (a) -0.020 0.000 0.000 0.000 -0.109 -0.696 -0.416 0.000 -0.018 0.000 -0.282 -0.254 -0.046 -0.025 0.000 -0.027

27 (b) -.019 .000 .000 -.090 -.309 -.603 -.360 .000 -.015 .000 -.150 -.135 -.052 -.029 .000 -.065

28 (c) -.026 .000 .000 -.003 -.180 -.712 -.425 .000 -.017 .000 -.183 -.164 -.087 -.075 .000 -.020

29 1990 (a) -.016 .000 .000 -.001 -.128 -.832 -.497 .000 -.018 .000 -.254 -.229 -.039 -.020 .000 -.001

30 (b) -.011 .000 .000 -.022 -.321 -1.076 -.643 .000 -.020 .000 -.411 -.370 -.046 -.024 .000 -.063

31 (c) -.015 .000 .000 -.011 -.216 -.938 -.560 .000 -.020 .000 -.310 -.279 -.050 -.020 .000 -.024

32 1991 (a) -.012 .000 -.001 -.024 -.161 -1.086 -.649 .000 -.020 .000 -.263 -.236 -.039 -.554 .000 -.002

33 (b) -.009 .000 -.002 -.102 -.253 -1.239 -.740 .000 -.017 -.001 -.189 -.170 -.031 -.020 .000 -.001

34 (c) -.013 .000 -.001 -.137 -.129 -1.279 -.764 .000 -.019 .000 -.246 -.222 -.026 -.014 .000 -.002

35 1992 (a) -.022 .000 -.001 -.001 -.111 -1.385 -.827 .000 -.028 .000 -.130 -.117 -.004 -.002 .000 -.001

36 (b) -.009 .000 -.010 -.124 -.334 -1.166 -.696 .000 -.029 -.001 -.276 -.249 .000 .000 .000 -.003

37 (c) -.012 .000 -.001 -.004 -.156 -1.073 -.641 .000 -.038 -.001 -.274 -.247 .000 .000 .000 -.002

38 1993 (a) -.011 .000 -.002 -.001 -.137 -1.237 -.739 .000 -.023 .000 -.282 -.254 .000 .000 .000 -.002

39 (b) -.014 .000 -.036 -.024 -.295 -1.183 -.706 .000 -.022 .000 -.277 -.249 .000 .000 .000 -.003

40 (c) -.005 .000 -.354 -.008 -.144 -.793 -.474 .000 -.021 .000 -.239 -.215 .000 .000 .000 -.002

41 1994 (a) -.006 .000 -.001 -.005 -.132 -.950 -.567 .000 -.032 -.001 -.170 -.153 .000 .000 .000 -.002

42 (b) -.017 .000 -.003 -.024 -.294 -.839 -.501 .000 -.079 .000 -.303 -.272 .000 .000 .000 -.001

43 (c) -.005 .000 -.003 -.330 -.153 -.593 -.354 .000 -.031 -.001 -.153 -.138 .000 .000 .000 -.003

44 1995 (a) -.005 .000 -.001 -.064 -.168 -.627 -.374 .000 -.038 .000 -.059 -.053 -.007 -.004 .000 -.001

45 (b) -.006 .000 -.006 -.006 -.235 -.638 -.381 .000 -.032 .000 -.065 -.059 -.010 -.008 .000 -.030

46 (c) -.004 .000 -.002 -.162 -.092 -.705 -.421 .000 -.027 .000 -.068 -.061 -.011 -.008 .000 -.023
184 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued [Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration] Stress period Simulated year Four month period Map No. and local name corresponding to well 24 28 29 34 50 51 66 67 68 69 80 81 82 86 87 88 89 ANP 8 ARA 2 ARA 3 BADGING FACILITY CFA 1 CFA 2 CPP 1 CPP 2 CPP 3 CPP 4 EBR 1 EBR 2-1 EBR II-2 FET1 FET2 FET DISP3 FIRE STA2 Layer 2

1 19801 -0.030 0.000 -0.013 -0.253 -0.247 -0.503 0.305 -0.024 -0.003 -0.030 -0.086 -0.155

2 1981 (a) -.032 .000 .000 -.142 -.327 -.665 .411 -.019 -.002 -.021 -.077 -.084

3 (b) -.038 .000 -.035 -.344 -.299 -.609 .374 -.023 -.003 -.039 -.034 -.191

4 (c) -.034 .000 -.005 -.197 -.349 -.710 .000 -.023 -.002 -.032 -.041 -.155

5 1982 (a) -.028 .000 -.003 -.140 -.362 -.736 .000 -.026 -.001 -.022 -.053 -.092

6 (b) -.033 .000 -.105 -.213 -.309 -.630 .000 -.024 -.002 -.035 -.063 -1.170

7 (c) -.035 .000 -.115 -.036 -.315 -.642 .000 -.023 -.001 -.019 -.051 -.139

8 1983 (a) -.032 .000 -.003 -.156 -.284 -.577 .000 -.021 .000 -.022 -.020 .169

9 (b) -.032 .000 -.038 -.335 -.369 -.752 .000 -.016 .000 -.029 -.062 -.132

10 (c) -.033 .000 -.036 -.157 -.332 -.675 .000 -.012 -.001 -.028 -.013 -.186

11 1984 (a) -.020 .000 -.055 -.082 -.346 -.704 .000 -.012 .000 -.020 -.010 -.119

12 (b) -.007 .000 -.126 -.149 -.352 -.717 .000 -.013 -.002 -.034 -.027 -.009

13 (c) -.011 .000 -.083 -.095 -.284 -.578 .000 -.012 -.001 -.032 -.133 -.072

14 1985 (a) -.010 .000 -.059 -.087 -.258 -.526 .000 -.013 -.005 -.028 -.053 -.061

15 (b) -.006 .000 -.170 -.187 -.278 -.566 .000 -.011 -.003 -.040 -.125 -.128

16 (c) -.010 .000 -.056 -.104 -.345 -.703 .000 -.009 -.001 -.033 -.055 -.106

17 1986 (a) -.006 .000 -.048 -.080 -.341 -.694 .000 -.014 .000 -.026 -.035 -.070

18 (b) -.005 .000 -.120 -.195 -.343 -.699 .000 -.012 .000 -.043 -.022 -.043

19 (c) -.012 .000 -.078 -.094 -.340 -.691 .000 -.012 .000 -.035 -.022 -.049

20 1987 (a) -.008 .000 -.050 -.070 -.357 -.728 .000 -.016 .000 -.032 -.017 -.054

21 (b) -.010 .000 -.143 -.119 -.367 -.746 .000 -.015 .000 -.042 -.022 -.046

22 (c) -.012 .000 -.081 -.088 -.343 -.698 .000 -.015 .000 -.041 -.024 -.055

23 1988 (a) -.010 .000 .000 -.167 -.358 -.728 .000 -.017 .000 -.030 -.019 -.041

24 (b) -.020 .000 -.037 -.486 -.346 -.703 .000 -.015 .000 -.045 .000 .000

25 (c) -.004 .000 -.011 -.209 -.303 -.616 .000 -.015 .000 -.040 .000 .000
Appendix F 185

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]

Stress 

period

Simulated 

year

Four 

month 

period

Map No. and local name corresponding to well

24 28 29 34 50 51 66 67 68 69 80 81 82 86 87 88 89

ANP 8 ARA 2 ARA 3 BADGING FACILITY CFA 1 CFA 2 CPP 1 CPP 2 CPP 3 CPP 4 EBR 1 EBR 2-1 EBR II-2 FET1 FET2 FET DISP3 FIRE STA2

Layer 2—Continued

26 1989 (a) 0.000 0.000 0.000 -0.164 -0.271 -0.551 0.000 -0.018 0.000 -0.028 -0.012 -0.025

27 (b) .000 .000 -.055 -.464 -.235 -.478 .000 -.015 .000 -.015 -.014 -.029

28 (c) .000 .000 -.002 -.270 -.277 -.563 .000 -.017 .000 -.018 -.023 -.075

29 1990 (a) .000 .000 -.001 -.192 -.324 -.659 .000 -.018 .000 -.025 -.010 -.020

30 (b) .000 .000 -.014 -.482 -.418 -.852 .000 -.020 .000 -.041 -.012 -.024

31 (c) .000 .000 -.006 -.324 -.365 -.743 .000 -.020 .000 -.031 -.013 -.020

32 1991 (a) .000 -.001 -.003 -.241 -.422 -.860 .000 -.020 .000 -.026 -.010 -.554

33 (b) .000 -.001 -.062 -.379 -.482 -.981 .000 -.017 -.001 -.019 -.008 -.020

34 (c) .000 -.001 -.084 -.194 -.497 -1.012 .000 -.019 .000 -.025 -.007 -.014

35 1992 (a) .000 .000 -.001 -.166 -.539 -1.096 .000 -.028 .000 -.013 -.001 -.002

36 (b) .000 -.006 -.076 -.501 -.543 -.923 .000 -.029 -.001 -.028 .000 .000

37 (c) .000 -.001 -.003 -.243 -.417 -.849 .000 -.038 -.001 -.027 .000 .000

38 1993 (a) .000 -.001 .000 -.206 -.481 -.979 .000 -.023 .000 -.028 .000 .000

39 (b) .000 -.021 -.015 -.443 -.460 -.936 .000 -.022 .000 -.028 .000 .000

40 (c) .000 -.208 -.005 -.216 -.308 -.628 .000 -.021 .000 -.024 .000 .000

41 1994 (a) .000 -.001 -.003 -.196 -.369 -.752 .000 -.032 -.001 -.017 .000 .000

42 (b) .000 -.002 -.015 -.442 -.326 -.664 .000 -.079 .000 -.030 .000 .000

43 (c) .000 -.002 -.202 -.229 -.231 -.470 .000 -.031 -.001 -.015 .000 .000

44 1995 (a) .000 -.001 -.039 -.252 -.244 -.496 .000 -.038 .000 -.006 -.002 -.004

45 (b) .000 -.004 -.004 -.353 -.248 -.505 .000 -.032 .000 -.007 -.003 -.008

46 (c) .000 -.001 -.100 -.138 -.274 -.558 .000 -.027 .000 -.007 -.003 -.008
186 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued [Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration] Stress period Simulated year Four month period Map No. and local name corresponding to well 24 28 29 34 50 51 66 67 68 69 80 81 82 86 87 88 89 ANP 8 ARA 2 ARA 3 BADGING FACILITY CFA 1 CFA 2 CPP 1 CPP 2 CPP 3 CPP 4 EBR 1 EBR 2-1 EBR II-2 FET1 FET2 FET DISP3 FIRE STA2 Layer 3

1 19801 -0.012 -0.003 -0.059

2 1981 (a) -.010 -.002 -.032

3 (b) -.011 -.003 -.073

4 (c) -.011 -.002 -.059

5 1982 (a) -.013 -.001 -.035

6 (b) -.012 -.002 -.446

7 (c) -.011 -.001 -.053

8 1983 (a) -.010 .000 -.064

9 (b) -.008 .000 -.050

10 (c) -.006 -.001 -.071

11 1984 (a) -.006 .000 -.046

12 (b) -.006 -.002 -.003

13 (c) -.006 -.001 -.027

14 1985 (a) -.006 -.005 -.023

15 (b) -.006 -.005 -.049

16 (c) -.005 -.001 -.040

17 1986 (a) -.007 .000 -.027

18 (b) -.006 .000 -.017

19 (c) -.006 .000 -.019

20 1987 (a) -.008 .000 -.021

21 (b) -.007 .000 -.018

22 (c) -.007 .000 -.021

23 1988 (a) -.009 .000 -.016

24 (b) -.007 .000 .000

25 (c) -.007 .000 .000
Appendix F 187

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]

Stress 

period

Simulated 

year

Four 

month 

period

Map No. and local name corresponding to well

24 28 29 34 50 51 66 67 68 69 80 81 82 86 87 88 89

ANP 8 ARA 2 ARA 3 BADGING FACILITY CFA 1 CFA 2 CPP 1 CPP 2 CPP 3 CPP 4 EBR 1 EBR 2-1 EBR II-2 FET1 FET2 FET DISP3 FIRE STA2

Layer 3—Continued

26 1989 (a) -0.009 0.000 -0.010

27 (b) -.008 .000 -.011

28 (c) -.008 .000 -.029

29 1990 (a) -.009 .000 -.008

30 (b) -.010 .000 -.009

31 (c) -.010 .000 -.007

32 1991 (a) -.010 .000 -.211

33 (b) -.008 -.001 -.008

34 (c) .000 .000 -.005

35 1992 (a) -.014 .000 -.001

36 (b) -.014 -.001 .000

37 (c) -.019 -.001 .000

38 1993 (a) -.012 .000 .000

39 (b) -.011 .000 .000

40 (c) -.011 .000 .000

41 1994 (a) -.016 -.001 .000

42 (b) -.039 .000 .000

43 (c) -.015 -.001 .000

44 1995 (a) -.019 .000 -.001

45 (b) -.016 .000 -.003

46 (c) -.013 .000 -.003
188 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued [Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration] Stress period Simulated year Four month period Map No. and local name corresponding to well 24 28 29 34 50 51 66 67 68 69 80 81 82 86 87 88 89 ANP 8 ARA 2 ARA 3 BADGING FACILITY CFA 1 CFA 2 CPP 1 CPP 2 CPP 3 CPP 4 EBR 1 EBR 2-1 EBR II-2 FET1 FET2 FET DISP3 FIRE STA2 Layer 4

1 19801 -0.024 -0.005

2 1981 (a) -.030 -.004

3 (b) -.024 -.006

4 (c) -.017 -.003

5 1982 (a) -.015 -.002

6 (b) -.019 -.004

7 (c) -.018 -.001

8 1983 (a) -.015 .000

9 (b) -.017 .000

10 (c) -.015 .000

11 1984 (a) -.011 .000

12 (b) -.014 .000

13 (c) -.012 .000

14 1985 (a) -.012 .000

15 (b) -.021 .000

16 (c) -.015 .000

17 1986 (a) -.010 .000

18 (b) -.024 .000

19 (c) -.034 .000

20 1987 (a) -.032 .000

21 (b) -.048 .000

22 (c) -.048 .000

23 1988 (a) -.018 .000

24 (b) .000 .000

25 (c) .000 .000
Appendix F 189

Stress 

period

Simulated 

year

Four 

month 

period

Map No. and local name corresponding to well

24 28 29 34 50 51 66 67 68 69 80 81 82 86 87 88 89

ANP 8 ARA 2 ARA 3 BADGING FACILITY CFA 1 CFA 2 CPP 1 CPP 2 CPP 3 CPP 4 EBR 1 EBR 2-1 EBR II-2 FET1 FET2 FET DISP3 FIRE STA2

Layer 4—Continued

26 1989 (a) 0.000 0.000

27 (b) .000 .000

28 (c) .000 .000

29 1990 (a) .000 .000

30 (b) .000 .000

31 (c) .000 -.001

32 1991 (a) .000 .000

33 (b) .000 -.001

34 (c) .000 -.001

35 1992 (a) .000 -.001

36 (b) .000 -.001

37 (c) .000 -.001

38 1993 (a) .000 .000

39 (b) .000 .000

40 (c) .000 .000

41 1994 (a) .000 -.001

42 (b) .000 -.001

43 (c) .000 -.001

44 1995 (a) .000 -.001

45 (b) .000 .000

46 (c) .000 .000

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
190 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Stress period Simulated year Four month period Map No. and local name corresponding to well 24 28 29 34 50 51 66 67 68 69 80 81 82 86 87 88 89 ANP 8 ARA 2 ARA 3 BADGING FACILITY CFA 1 CFA 2 CPP 1 CPP 2 CPP 3 CPP 4 EBR 1 EBR 2-1 EBR II-2 FET1 FET2 FET DISP3 FIRE STA2 Layer 5

1 19801 -0.048

2 1981 (a) -.058

3 (b) -.046

4 (c) -.033

5 1982 (a) -.029

6 (b) -.036

7 (c) -.036

8 1983 (a) -.029

9 (b) -.033

10 (c) -.028

11 1984 (a) -.021

12 (b) -.027

13 (c) -.023

14 1985 (a) -.024

15 (b) -.040

16 (c) -.029

17 1986 (a) -.020

18 (b) -.046

19 (c) -.066

20 1987 (a) -.061

21 (b) -.094

22 (c) -.093

23 1988 (a) -.035

24 (b) .000

25 (c) .000

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
Appendix F 191

Stress 

period

Simulated 

year

Four 

month 

period

Map No. and local name corresponding to well

24 28 29 34 50 51 66 67 68 69 80 81 82 86 87 88 89

ANP 8 ARA 2 ARA 3 BADGING FACILITY CFA 1 CFA 2 CPP 1 CPP 2 CPP 3 CPP 4 EBR 1 EBR 2-1 EBR II-2 FET1 FET2 FET DISP3 FIRE STA2

Layer 5—Continued

26 1989 (a) 0.000

27 (b) .000

28 (c) .000

29 1990 (a) .000

30 (b) .000

31 (c) .000

32 1991 (a) .000

33 (b) .000

34 (c) .000

35 1992 (a) .000

36 (b) .000

37 (c) .000

38 1993 (a) .000

39 (b) .000

40 (c) .000

41 1994 (a) .000

42 (b) .000

43 (c) .000

44 1995 (a) .000

45 (b) .000

46 (c) .000

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
192 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Stress period Simulated year Four month period Map number and Local name corresponding to well 118 131 132 133 134 191 205 206 207 208 238 239 240 245 LPTF DISP NRF 1 NRF 2 NRF 3 NRF 4 RWMC SPERT 

1

SPERT 

2 TAN 1 TAN 2 TRA 1 TRA 3 TRA 4 TRA DISP

Layer 1

1 19801 0.136 -0.598 0.000 0.000 -0.001 -0.058 -0.046 -0.014 -0.174 -0.016 0.874

2 1981 (a) .121 -2.198 .000 .000 -.006 -.016 -.020 -.034 -.148 .000 .733

3 (b) .092 -.205 -.043 .000 -.016 -.033 -.024 -.053 -.184 -.029 .690

4 (c) .165 -1.112 .000 .000 -.032 -.034 -.252 -3.440 -.125 -.002 .511

5 1982 (a) .087 -1.464 -.004 .000 -.031 -.056 -.042 -.006 -.082 -.009 .299

6 (b) .061 -.780 -.001 .000 -.012 -.019 -.027 -.038 -.259 -.008 .000

7 (c) .059 -.866 -.060 .000 -.023 -.031 -.020 -.031 -.221 -.028 .000

8 1983 (a) .061 -.300 -.002 .000 -.009 -.053 -.007 -.043 -.094 -.018 .000

9 (b) .061 -.377 -.001 .000 -.009 -.044 -.011 -.073 -.148 .000 .000

10 (c) .104 -.453 .000 .000 -.002 -.024 -.011 -.060 -.039 -.111 .000

11 1984 (a) .149 -.321 -.001 .000 -.005 -.035 -.009 -.055 -1.506 -.040 .000

12 (b) .191 -.356 -.008 .000 -.004 -.042 -.007 -.072 -.245 -.130 .000

13 (c) .079 -1.210 -.083 .000 -.002 -.027 -.017 -.048 -1.053 -.338 .000

14 1985 (a) .000 -1.472 -.005 .000 -.002 -.021 -.015 -.057 -.056 -.647 .000

15 (b) .000 -2.548 -.009 .000 -.013 -.024 -.024 -.048 -1.276 -.400 .000

16 (c) .000 -1.349 -.105 .000 -.015 -.030 -.011 -.054 -.005 -.001 .000

17 1986 (a) .000 -1.553 -.319 .000 -.014 -.036 -.022 -.053 -.040 -.199 .000

18 (b) .000 -1.212 -.687 .000 -.016 -.018 -.056 -.063 -.089 -.001 .000

19 (c) .000 -1.443 -.025 .000 -.012 -.009 -.056 -.048 -.269 .000 .000

20 1987 (a) .000 -1.968 -.493 .000 -.008 -.002 -.043 -.051 -.254 -.003 .000

21 (b) .000 -.802 -.146 .000 -.009 -.015 -.049 -.077 -.455 -.091 .000

22 (c) .000 -.061 -.811 .000 -.009 -.047 -.045 -.051 -.029 .000 .000

23 1988 (a) .000 -.063 -.698 .000 -.007 -.043 -.035 -.070 -1.166 -.712 .000

24 (b) .000 -.836 -.436 .000 -.014 -.009 -.006 -.141 -2.470 .000 .000

25 (c) .000 -.902 -.036 .000 -.007 -.022 -.075 -.057 -.802 -.033 .000

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
Appendix F 193

Stress 

period

Simulated 

year

Four 

month 

period

Map number and Local name corresponding to well

118 131 132 133 134 191 205 206 207 208 238 239 240 245

LPTF 

DISP NRF 1 NRF 2 NRF 3 NRF 4 RWMC SPERT 1 SPERT 2 TAN 1 TAN 2 TRA 1 TRA 3 TRA 4 TRA DISP

Layer 1—Continued

26 1989 (a) 0.000 -0.724 -0.006 0.000 -0.008 -0.003 -0.046 -0.054 -0.489 -0.011 0.000

27 (b) .000 -.992 -.018 .000 -.025 -.014 -.056 -.064 -.938 -.058 .000

28 (c) .000 -.605 -.266 .000 -.011 -.007 -.067 -.081 -1.008 -.017 .000

29 1990 (a) .000 -.111 -1.972 -.024 -.004 -.013 -.044 -.024 -.345 .000 .000

30 (b) .000 -.022 -.566 -.113 -.009 -.015 -.087 -.006 -.640 -.013 .000

31 (c) .000 -.009 -.371 -.116 -.010 -.017 -.044 -.043 -.142 -.024 .000

32 1991 (a) .000 -.001 -.595 -.142 -.011 -.009 -.098 .000 -.228 -.004 .000

33 (b) .000 -.040 -.982 -.256 -.009 -.023 -.048 -.061 -.689 .000 .000

34 (c) .000 -.002 -.672 -.234 -.005 -.016 -.004 -.079 -.952 -.016 .000

35 1992 (a) .000 -.012 -.617 -.210 -.174 -.005 -.013 -.072 -.097 .000 .000

36 (b) .000 -.104 -.829 -.278 -.182 -.011 -.035 -.076 -.456 -.157 .000

37 (c) .000 -.001 -.794 -.307 -.008 -.007 -.039 -.026 -.153 .000 .000

38 1993 (a) .000 -.001 -.521 -.203 -.007 -.003 -.044 -.027 -.799 -.086 .000

39 (b) .000 -.116 -.617 -.254 -.016 -.015 -.041 -.052 -.156 .000 .000

40 (c) .000 -.024 -.503 -.226 -.022 -.014 -.043 -.057 .000 .000 .000

41 1994 (a) .000 -.065 -.284 -.207 -.010 -.013 -.044 -.045 -.012 .000 .000

42 (b) .000 -.135 -.129 -.266 -.058 -.019 -.072 -.038 .000 .000 .000

43 (c) .000 -.029 -.126 -.229 -.016 -.007 -.021 -.054 -.041 .000 .000

44 1995 (a) .000 -.012 -.119 -.247 -.007 -.006 -.047 -.027 -.768 -.297 .000

45 (b) .000 -.083 -.106 -.134 -.016 -.009 -.032 -.052 -.684 -.496 .000

46 (c) .000 -.044 -.101 -.083 -.027 -.007 -.031 -.046 -.496 -.257 .000

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
194 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Stress period Simulated year Four month period Map number and Local name corresponding to well 118 131 132 133 134 191 205 206 207 208 238 239 240 245 LPTF DISP NRF 1 NRF 2 NRF 3 NRF 4 RWMC SPERT 

1

SPERT 

2 TAN 1 TAN 2 TRA 1 TRA 3 TRA 4 TRA DISP

Layer 2—Continued

26 1989 (a) -0.080 -0.001 0.000 -0.004 -0.001 -0.017 -0.007 -0.138 -0.005 0.000

27 (b) -.110 -.008 .000 -.011 -.003 -.021 -.009 -.265 -.029 .000

28 (c) -.067 -.007 .000 -.005 -.002 -.025 -.011 -.284 -.009 .000

29 1990 (a) -.012 -.006 -.006 -.002 -.003 -.016 -.003 -.097 .000 .000

30 (b) -.002 -.007 -.029 -.004 -.003 -.032 -.001 -.180 -.006 .000

31 (c) -.001 -.010 -.030 -.005 -.004 -.016 -.006 -.040 -.012 .000

32 1991 (a) .000 -.015 -.036 -.005 -.002 -.036 .000 -.064 -.002 .000

33 (b) -.004 .000 -.065 -.004 -.005 -.018 -.008 -.194 .000 .000

34 (c) .000 -.004 -.059 -.002 -.005 -.002 -.011 -.268 -.008 .000

35 1992 (a) -.001 -.006 -.054 -.078 -.001 -.005 -.010 -.027 .000 .000

36 (b) -.012 -.002 -.071 -.082 -.003 -.013 -.010 -.129 -.077 .000

37 (c) .000 -.002 -.078 -.003 -.002 -.014 -.004 -.043 .000 .000

38 1993 (a) .000 -.004 -.052 -.003 -.001 -.016 -.004 -.225 -.043 .000

39 (b) -.013 -.006 -.064 -.007 -.004 -.015 -.007 -.044 .000 .000

40 (c) -.003 -.001 -.057 -.010 -.003 -.016 -.008 .000 .000 .000

41 1994 (a) -.007 -.005 -.053 -.005 -.003 -.016 -.006 -.003 .000 .000

42 (b) -.015 -.001 -.068 -.026 -.005 -.027 -.005 .000 .000 .000

43 (c) -.003 -.001 -.058 -.007 -.002 -.008 -.007 -.012 .000 .000

44 1995 (a) -.001 -.001 -.063 -.003 -.001 -.018 -.004 -.217 -.146 .000

45 (b) -.009 -.001 -.034 -.007 -.002 -.012 -.007 -.193 -.244 .000

46 (c) -.005 -.001 -.021 -.012 -.002 -.011 -.006 -.140 -.127 .000

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
Appendix F 195

Stress 

period

Simulated 

year

Four 

month 

period

Map number and Local name corresponding to well

118 131 132 133 134 191 205 206 207 208 238 239 240 245

LPTF 

DISP NRF 1 NRF 2 NRF 3 NRF 4 RWMC SPERT 1 SPERT 2 TAN 1 TAN 2 TRA 1 TRA 3 TRA 4 TRA DISP

Layer 3

1 19801 0.000

2 1981 (a) .000

3 (b) .000

4 (c) .000

5 1982 (a) .000

6 (b) .000

7 (c) .000

8 1983 (a) .000

9 (b) .000

10 (c) .000

11 1984 (a) .000

12 (b) .000

13 (c) .000

14 1985 (a) .000

15 (b) .000

16 (c) .000

17 1986 (a) .000

18 (b) .000

19 (c) .000

20 1987 (a) .000

21 (b) .000

22 (c) .000

23 1988 (a) .000

24 (b) .000

25 (c) .000

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
196 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Stress period Simulated year Four month period Map number and Local name corresponding to well 118 131 132 133 134 191 205 206 207 208 238 239 240 245 LPTF DISP NRF 1 NRF 2 NRF 3 NRF 4 RWMC SPERT 

1

SPERT 

2 TAN 1 TAN 2 TRA 1 TRA 3 TRA 4 TRA DISP

Layer 3—Continued

26 1989 (a) 0.000

27 (b) .000

28 (c) .000

29 1990 (a) -.011

30 (b) -.050

31 (c) -.051

32 1991 (a) -.062

33 (b) -.113

34 (c) -.103

35 1992 (a) -.093

36 (b) -.123

37 (c) -.135

38 1993 (a) -.089

39 (b) -.112

40 (c) -.100

41 1994 (a) -.091

42 (b) -.117

43 (c) -.101

44 1995 (a) -.109

45 (b) -.059

46 (c) -.036

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
Appendix F 197

Stress 

period

Simulated 

year

Four 

month 

period

Map number and Local name corresponding to well

118 131 132 133 134 191 205 206 207 208 238 239 240 245

LPTF 

DISP NRF 1 NRF 2 NRF 3 NRF 4 RWMC SPERT 1 SPERT 2 TAN 1 TAN 2 TRA 1 TRA 3 TRA 4 TRA DISP

Layer 4

1 19801 -0.001 -2.504 0.069

2 1981 (a) .000 -2.250 .058

3 (b) .000 -2.629 .055

4 (c) .000 -2.197 .041

5 1982 (a) -.001 -2.481 .024

6 (b) -.006 -2.370 .000

7 (c) -.003 -2.404 .000

8 1983 (a) -.002 -2.506 .000

9 (b) -.004 -2.737 .000

10 (c) -.003 -2.646 .000

11 1984 (a) -.002 -.688 .000

12 (b) -.006 -2.421 .000

13 (c) -.002 -.759 .000

14 1985 (a) -.003 -1.318 .000

15 (b) -.002 -.686 .000

16 (c) .000 -2.504 .000

17 1986 (a) -.001 -1.876 .000

18 (b) -.001 -2.568 .000

19 (c) -.001 -2.410 .000

20 1987 (a) -.001 -2.426 .000

21 (b) -.003 -2.361 .000

22 (c) .000 -2.823 .000

23 1988 (a) -.001 -.496 .000

24 (b) -.006 .000 .000

25 (c) -.002 -2.066 .000

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
198 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Stress period Simulated year Four month period Map number and Local name corresponding to well 118 131 132 133 134 191 205 206 207 208 238 239 240 245 LPTF DISP NRF 1 NRF 2 NRF 3 NRF 4 RWMC SPERT 

1

SPERT 

2 TAN 1 TAN 2 TRA 1 TRA 3 TRA 4 TRA DISP

Layer 4—Continued

26 1989 (a) -0.001 -1.740 0.000

27 (b) -.002 -1.555 .000

28 (c) .000 -1.614 .000

29 1990 (a) -.001 -2.215 .000

30 (b) -.001 -2.724 .000

31 (c) -.001 -2.642 .000

32 1991 (a) .000 -2.242 .000

33 (b) -.002 -1.996 .000

34 (c) -.003 -1.323 .000

35 1992 (a) .000 -2.249 .000

36 (b) -.001 -1.772 .000

37 (c) -.001 -2.308 .000

38 1993 (a) .000 -1.334 .000

39 (b) .000 -1.589 .000

40 (c) .000 -2.313 .000

41 1994 (a) .000 -1.751 .000

42 (b) -.001 -1.808 .000

43 (c) -.001 -2.295 .000

44 1995 (a) -.001 -.706 .000

45 (b) -.001 -.941 .000

46 (c) .000 -1.462 .000

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
Appendix F 199

Stress 

period

Simulated 

year

Four 

month 

period

Map number and Local name corresponding to well

118 131 132 133 134 191 205 206 207 208 238 239 240 245

LPTF 

DISP NRF 1 NRF 2 NRF 3 NRF 4 RWMC SPERT 1 SPERT 2 TAN 1 TAN 2 TRA 1 TRA 3 TRA 4 TRA DISP

Layer 5

1 19801 -0.007

2 1981 (a) .000

3 (b) .000

4 (c) -.002

5 1982 (a) -.015

6 (b) -.078

7 (c) -.044

8 1983 (a) -.029

9 (b) -.055

10 (c) -.037

11 1984 (a) -.027

12 (b) -.079

13 (c) -.029

14 1985 (a) -.037

15 (b) -.030

16 (c) -.004

17 1986 (a) -.015

18 (b) -.013

19 (c) -.019

20 1987 (a) -.007

21 (b) -.040

22 (c) -.003

23 1988 (a) -.010

24 (b) -.077

25 (c) -.026

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
200 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho Stress period Simulated year Four month period Map number and Local name corresponding to well 118 131 132 133 134 191 205 206 207 208 238 239 240 245 LPTF DISP NRF 1 NRF 2 NRF 3 NRF 4 RWMC SPERT 

1

SPERT 

2 TAN 1 TAN 2 TRA 1 TRA 3 TRA 4 TRA DISP

Layer 5—Continued

26 1989 (a) -0.011

27 (b) -.029

28 (c) -.003

29 1990 (a) -.016

30 (b) -.014

31 (c) -.014

32 1991 (a) -.004

33 (b) -.023

34 (c) -.040

35 1992 (a) -.005

36 (b) -.017

37 (c) -.009

38 1993 (a) -.005

39 (b) -.001

40 (c) .000

41 1994 (a) .000

42 (b) -.008

43 (c) -.008

44 1995 (a) -.008

45 (b) -.009

46 (c) -.005

1 Steady-state stress period.

Table F1. Industrial well withdrawals or injections used for steady-state and transient models of groundwater flow, Idaho National Laboratory, Idaho.—Continued[Values are in cubic feet per second. Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well identifier used in this study. Transient stress periods: (a) January through April, (b) May through August, (c) September through December. Negative entries are withdrawals and positive entries are injection or infiltration]
Appendix G 201

Appendix G. Water-Level Data Used to Represent 1980 

Steady-State Head for Calibration of Steady-State and 

Transient Models of Groundwater Flow, Idaho National 

Laboratory and Vicinity, Idaho
202 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table G1. Water-level data used to represent 1980 steady-state head for the calibration of steady-state and transient models of 

groundwater flow, Idaho National Laboratory and vicinity, Idaho.

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

identifier used in this study. Observation name: Model observation name used in this study. Weighting statistic: Variance of the measurement error of head. 

Abbreviation: ft, foot]

Map 

No.

Site 

identifier

Local 

name

Observation 

name

Date 

measured

Observed head 

(ft)

 Weighting 

statistic (1/ft)

1 434819112380501 2ND OWSLEY 2dOwsly_780 July 1980 4,561.62 1.50

2 434556112575601 434556 434556_491 Apr. 1991 4,551.63 9.20

3 434647112534101 434647 434647_491 Apr. 1991 4,530.43 9.20

4 434650112545501 434650 434650_880 Aug. 1980 4,513.64 3.30

5 434714112175801 434714 434714_1180 Nov. 1980 4,554.20 9.20

6 434726112244101 434726 434726_889 Aug. 1989 4,533.95 9.20

7 434756112212101 434756 434756_1291 Dec. 1991 4,541.57 9.20

8 435026112253101 435026 435026_1180 Nov. 1980 4,562.86 9.20

9 435100112271601 435100 435100_1180 Nov. 1980 4,580.29 9.20

10 440109112391301 440109 440109_989 Sept. 1989 4,584.40 37.00

12 433534112392901 ANL MW 11 ANLMW11_1292 Dec. 1992 4,482.74 3.30

13 433545112394102 ANL MW 13 ANLMW13_1104 Nov. 2004 4,485.00 9.20

14 433545112394101 ANL OBS A 001 ANLOBSA_301 Mar. 2001 4,485.21 37.00

21 435308112454101 ANP 5 ANP5_780 July 1980 4,579.82 1.50

22 435152112443101 ANP 6 ANP6_780 July 1980 4,579.82 1.50

23 435522112444201 ANP 7 ANP7_780 July 1980 4,581.18 1.50

25 434856112400001 ANP 9 ANP9_1280 Dec. 1980 4,563.58 1.50

26 434909112400401 ANP 10 ANP10_780 July 1980 4,565.80 1.50

27 435053112423201 ANP DISP 3 ANPdsp3_784 July 1984 4,580.49 9.20

30 433509112384801 ARBOR TEST ArbrTst_1280 Dec. 1980 4,485.52 .37

31 433223112470201 AREA 2 Area2_780 July 1980 4,458.78 3.30

49 432618112555501 CERRO GRANDE CroGrnd_1280 Dec. 1980 4,426.37 .37

51 433144112563501 CFA 2 CFA2_189 Jan. 1989 4,457.15 3.30

55 433216112563301 CFA LF 2-10 CFAL210_691 June 1991 4,453.47 3.30

56 433230112561701 CFA LF 2-11 CFAL211_1289 Dec. 1989 4,459.32 9.20

59 433216112571001 CFA LF 3-9 CFALF39_1190 Nov. 1990 4,455.98 3.30

63 432927112410101 COREHOLE 1 CrHole1_1280 Dec. 1980 4,435.74 9.20

65 431519113112901 COX WELL CoxWell_849 Aug. 1949 4,319.47 37.00

69 433440112554401 CPP 4 CPP4_1083 Oct. 1983 4,466.00 9.20

69 433440112554402 CPP 5 CPP5_1193 Nov. 1993 4,457.50 9.20

74 434611112504301 DH 1B DH1B_1292 Dec. 1992 4,527.08 9.20

75 434547112512801 DH 2A DH2A_293 Feb. 1993 4,526.58 9.20

83 431831113312901 ELLSWORTH Elswrth_567 May 1967 4,107.30 37.00

88 435124112433701 FET DISP 3 FETdsp3_592 May 1992 4,582.05 3.30

90 432424113165301 FNGR BUTTE FngrBtt_1072 Oct. 1972 4,370.00 37.00

91 434947112414301 GIN 1 (old) GIN1old_592 May 1992 4,579.01 9.20

92 434949112413401 GIN 2 GIN2old_780 July 1980 4,577.43 3.30

93 434945112413101 GIN 3 (old) GIN3old_493 Apr. 1993 4,576.41 9.20

94 434949112413601 GIN 4 GIN4old_493 Apr. 1993 4,576.50 3.30
Appendix G 203

Map 

No.

Site 

identifier

Local 

name

Observation 

name

Date 

measured

Observed head 

(ft)

 Weighting 

statistic (1/ft)

95 434953112413301 GIN 5 (old) GIN5old_493 Apr. 1993 4,576.61 9.20

114 431439113071401 Houghland Hghlnd_380 Mar. 1980 4,379.85 37.00

115 435153112420501 IET 1 DISP IETdisp_780 July 1980 4,580.32 3.30

121 434700112530401 ML 11 ML11_491 Apr. 1991 4,534.45 9.20

122 434558112585301 ML 12 ML12_880 Aug. 1980 4,534.71 3.30

123 434723112552701 ML 13 ML13_380 1 Mar. 1980 4,535.40 9.20

124 433520112572601 MTR TEST MTRtest_1280 Dec. 1980 4,457.62 1.50

128 435038112453401 NO NAME 1 NoName1_780 July 1980 4,577.82 9.20

129 433449112523101 NPR TEST NPRtest_1191 Nov. 1991 4,470.70 3.30

136 433910112550101 NRF 6 NRF6_991 Sept. 1991 4,479.04 3.30

138 433920112543601 NRF 7 NRF7_991 Sept. 1991 4,479.16 3.30

140 433843112550901 NRF 8 NRF8_898 Aug. 1998 4,479.23 3.30

141 433840112550201 NRF 9 NRF9_898 Aug. 1998 4,478.27 3.30

142 433841112545201 NRF 10 NRF10_898 Aug. 1998 4,479.15 3.30

143 433847112544201 NRF 11 NRF11_898 Aug. 1998 4,479.66 3.30

144 433855112543201 NRF 12 NRF12_898 Aug. 1998 4,478.38 3.30

145 433928112545401 NRF 13 NRF13_898 Aug. 1998 4,478.35 3.30

150 435416112460401 P&W 1 P&W1_780 July 1980 4,580.07 1.50

151 435419112453101 P&W 2 P&W2_780 July 1980 4,579.83 1.50

152 435443112435801 P&W 3 P&W3_780 July 1980 4,580.32 1.50

155 434941112454201 PSTF TEST PSTFtst_780 July 1980 4,578.32 1.50

170 432632113095901 QAB QAB_282 Feb. 1982 4,424.48 37.00

184 432956113030901 RWMC M1SA WMCM1SA_1192 Nov. 1992 4,425.56 3.30

185 433008113021801 RWMC M3S RWMCM3S_1192 Nov. 1992 4,426.38 3.30

186 432939113030101 RWMC M4D RWMCM4D_1192 Nov. 1992 4,427.19 3.30

187 432931113015001 RWMC M6S RWMCM6S_1192 Nov. 1992 4,425.51 3.30

188 433023113014801 RWMC M7S RWMCM7S_1192 Nov. 1992 4,426.97 3.30

196 432854113201002 SITE 1 Site1_1280 Dec. 1980 4,378.26 37.00

197 431946113161401 SITE 2 Site2_1280 Dec. 1980 4,158.31 37.00

199 433826112510701 SITE 6 Site6_780 July 1980 4,478.20 1.50

200 433123112530101 SITE 9 Site9_1280 Dec. 1980 4,453.49 3.30

201 434334112463101 SITE 14 Site14_1280 Dec. 1980 4,524.51 1.50

202 433545112391501 SITE 16 Site16_780 July 1980 4,484.84 3.30

203 434027112575701 SITE 17 Site17_780 July 1980 4,483.84 1.50

204 433522112582101 SITE 19 Site19_780 July 1980 4,457.50 9.20

207 435056112420001 TAN 1 TAN1_1187 Nov. 1987 4,586.28 9.20

208 435100112420701 TAN 2 TAN2_1187 Nov. 1987 4,585.68 9.20

209 435104112420301 TAN 3 TAN3_190 Jan. 1990 4,582.74 9.20

210 435055112421302 TAN 5 TAN5_190 Jan. 1990 4,582.33 9.20

Table G1. Water-level data used to represent 1980 steady-state head for the calibration of steady-state and transient models of 

groundwater flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

identifier used in this study. Observation name: Model observation name used in this study. Weighting statistic: Variance of the measurement error of head. 

Abbreviation: ft, foot]
204 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Map 

No.

Site 

identifier

Local 

name

Observation 

name

Date 

measured

Observed head 

(ft)

 Weighting 

statistic (1/ft)

211 435039112412601 TAN 6 TAN6_990 Sept. 1990 4,582.27 9.20

212 435038112412601 TAN 7 TAN7_990 Sept. 1990 4,582.19 9.20

213 435034112421701 TAN 8 TAN8_80e 2 Dec. 1980e 4,578.53 9.20

214 435053112423202 TAN 9 TAN9_1289 Dec. 1989 4,584.85 9.20

216 435051112423201 TAN 10 A TAN10A_490 Apr. 1990 4,586.51 9.20

217 435050112423202 TAN 11 TAN11_1289 Dec. 1989 4,584.96 9.20

219 435040112423701 TAN 13 TAN13_1090 Oct. 1990 4,580.57 9.20

220 435040112423801 TAN 13A TAN13A_1190 Nov. 1990 4,578.82 9.20

221 435039112423701 TAN 14 TAN14_1090 Oct. 1990 4,580.89 9.20

222 435021112412701 TAN 15 TAN15_991 Sept. 1991 4,580.99 3.30

224 435034112421601 TAN 17 TAN17_80e 2 Dec. 1980e 4,578.98 9.20

225 435051112421401 TAN 18 TAN18_1192 Nov. 1992 4,576.95 3.30

226 435051112421501 TAN 19 TAN19_1092 Oct. 1992 4,577.69 3.30

227 435046112425001 TAN 20 TAN20_1092 Oct. 1992 4,577.86 3.30

228 435009112420001 TAN 21 TAN21_1092 Oct. 1992 4,575.98 3.30

229 435020112412702 TAN 22 TAN22_892 Aug. 1992 4,579.05 9.20

230 435019112412701 TAN 22A TAN22A_1092 Oct. 1992 4,577.09 9.20

231 435020112412703 TAN 23 TAN23_792 July 1992 4,578.76 9.20

231 435020112412704 TAN 23A TAN23A_1092 Oct. 1992 4,576.96 3.30

232 434942112411101 TAN 24 TAN24_992 Sept. 1992 4,576.61 9.20

232 434942112411001 TAN 24A TAN24A_1092 Oct. 1992 4,575.69 3.30

233 435058112423401 TAN CH 1 TANCH1_190 Jan. 1990 4,584.14 9.20

234 435033112421702 TAN CH 2B TANCH2b_401 Apr. 2001 4,577.41 9.20

242 433446112574701 TRA 6 TRA6_1290 Dec. 1990 4,455.60 9.20

243 433449112575901 TRA 7 TRA7_990 Sept. 1990 4,457.10 9.20

244 433431112580101 TRA 8 TRA8_1290 Dec. 1990 4,457.10 9.20

245 433506112572301 TRA DISP TRAdisp_791 July 1991 4,458.39 3.30

247 432700112470801 USGS 1 USGS1_1280 Dec. 1980 4,435.21 .37

248 433320112432301 USGS 2 USGS2_1280 Dec. 1980 4,466.83 1.50

250 434657112282201 USGS 4 USGS4_1280 Dec. 1980 4,531.61 3.30

251 433543112493801 USGS 5 USGS5_1280 Dec. 1980 4,469.86 .37

252 434031112453701 USGS 6 USGS6_1280 Dec. 1980 4,485.14 3.30

253 434915112443901 USGS 7 USGS7_1280 Dec. 1980 4,575.85 1.50

254 433121113115801 USGS 8 USGS8_1280 Dec. 1980 4,429.93 37.00

255 432740113044501 USGS 9 USGS9_1280 Dec. 1980 4,423.77 .37

256 432336113064201 USGS 11 USGS11_1280 Dec. 1980 4,415.68 1.50

257 434126112550701 USGS 12 USGS12_1280 Dec. 1980 4,490.67 9.20

258 432731113143902 USGS 13 USGS13_781 July 1981 4,388.64 9.20

259 432019112563201 USGS 14 USGS14_1280 Dec. 1980 4,418.12 1.50

Table G1. Water-level data used to represent 1980 steady-state head for the calibration of steady-state and transient models of 

groundwater flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

identifier used in this study. Observation name: Model observation name used in this study. Weighting statistic: Variance of the measurement error of head. 

Abbreviation: ft, foot]
Appendix G 205

Map 

No.

Site 

identifier

Local 

name

Observation 

name

Date 

measured

Observed head 

(ft)

 Weighting 

statistic (1/ft)

260 434234112551701 USGS 15 USGS15_780 July 1980 4,492.56 1.50

262 433937112515401 USGS 17 USGS17_1280 Dec. 1980 4,478.38 1.50

263 434540112440901 USGS 18 USGS18_1280 Dec. 1980 4,533.62 1.50

264 434426112575701 USGS 19 USGS19_1280 Dec. 1980 4,527.93 9.20

265 433253112545901 USGS 20 USGS20_1280 Dec. 1980 4,453.86 .37

266 434307112382601 USGS 21 USGS21_1280 Dec. 1980 4,506.06 1.50

267 433422113031701 USGS 22 USGS22_1280 Dec. 1980 4,438.13 .37

268 434055112595901 USGS 23 USGS23_1280 Dec. 1980 4,484.31 1.50

269 435053112420801 USGS 24 USGS24_780 July 1980 4,579.49 1.50

270 435339112444601 USGS 25 USGS25_1280 Dec. 1980 4,579.07 1.50

271 435212112394001 USGS 26 USGS26_1280 Dec. 1980 4,579.21 1.50

272 434851112321801 USGS 27 USGS27_380 Mar. 1980 4,560.28 1.50

273 434600112360101 USGS 28 USGS28_780 July 1980 4,541.02 1.50

274 434407112285101 USGS 29 USGS29_780 July 1980 4,522.48 1.50

275 434601112315403 USGS 30A USGS30A_1280 Dec. 1980 4,537.16 1.50

275 434601112315402 USGS 30B USGS30B_1280 Dec. 1980 4,528.16 1.50

275 434601112315401 USGS 30C USGS30C_1280 Dec. 1980 4,526.07 1.50

276 434625112342101 USGS 31 USGS31_780 July 1980 4,529.69 3.30

277 434444112322101 USGS 32 USGS32_780 July 1980 4,522.28 3.30

279 433334112565501 USGS 34 USGS34_780 July 1980 4,456.43 3.30

280 433339112565801 USGS 35 USGS35_780 July 1980 4,456.25 .37

281 433330112565201 USGS 36 USGS36_780 July 1980 4,456.53 .37

282 433326112564801 USGS 37 USGS37_1280 Dec. 1980 4,456.26 .37

283 433322112564301 USGS 38 GS38new_780 July 1980 4,456.59 .37

284 433343112570001 USGS 39 USGS39_780 July 1980 4,456.45 .37

285 433411112561101 USGS 40 GS40new_1280 Dec. 1980 4,457.25 .37

286 433409112561301 USGS 41 USGS41_780 July 1980 4,457.68 3.30

287 433404112561301 USGS 42 USGS42_780 July 1980 4,457.64 3.30

288 433415112561501 USGS 43 USGS43_780 July 1980 4,457.64 3.30

289 433409112562101 USGS 44 USGS44_780 July 1980 4,457.76 1.50

290 433402112561801 USGS 45 USGS45_780 July 1980 4,456.81 1.50

291 433407112561501 USGS 46 USGS46_1280 Dec. 1980 4,457.62 1.50

292 433407112560301 USGS 47 USGS47_780 July 1980 4,458.45 1.50

293 433401112560301 USGS 48 USGS48_780 July 1980 4,457.81 3.30

294 433403112555401 USGS 49 GS49new_1191 Nov. 1991 4,456.99 3.30

296 433350112560601 USGS 51 USGS51_780 July 1980 4,457.79 1.50

297 433414112554201 USGS 52 USGS52_780 July 1980 4,457.81 1.50

302 433344112562601 USGS 57 USGS57_780 July 1980 4,456.42 9.20

303 433500112572502 USGS 58 USGS58_1280 Dec. 1980 4,457.61 .37

Table G1. Water-level data used to represent 1980 steady-state head for the calibration of steady-state and transient models of 

groundwater flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

identifier used in this study. Observation name: Model observation name used in this study. Weighting statistic: Variance of the measurement error of head. 

Abbreviation: ft, foot]
206 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Map 

No.

Site 

identifier

Local 

name

Observation 

name

Date 

measured

Observed head 

(ft)

 Weighting 

statistic (1/ft)

304 433354112554701 USGS 59 USGS59_780 July 1980 4,457.49 1.50

310 433447112574501 USGS 65 USGS65_780 July 1980 4,458.28 .37

312 433344112554101 USGS 67 USGS67_780 July 1980 4,457.19 3.30

321 433425112573201 USGS 76 USGS76_780 July 1980 4,456.79 3.30

322 433315112560301 USGS 77 USGS77_380 Mar. 1980 4,456.95 1.50

324 433505112581901 USGS 79 USGS79_780 July 1980 4,457.40 3.30

327 433401112551001 USGS 82 USGS82_1280 Dec. 1980 4,457.37 3.30

328 433023112561501 USGS 83 USGS83_1280 Dec. 1980 4,442.82 3.30

329 433356112574201 USGS 84 USGS84_1280 Dec. 1980 4,456.35 .37

330 433246112571201 USGS 85 (old) USGS85_1280 Dec. 1980 4,456.00 1.50

331 432935113080001 USGS 86 USGS86_1280 Dec. 1980 4,428.72 1.50

332 433013113024201 USGS 87 USGS87_1080 Oct. 1980 4,430.13 .37

333 432940113030201 USGS 88 USGS88_1080 3 Oct. 1980 4,428.56 9.20

334 433005113032801 USGS 89 USGS89_1080 Oct. 1980 4,429.24 .37

335 432954113020501 USGS 90 USGS90_1080 Oct. 1980 4,427.83 .37

343 433807112551501 USGS 97 USGS97_1280 Dec. 1980 4,477.95 1.50

344 433657112563601 USGS 98 USGS98_780 July 1980 4,472.15 3.30

345 433705112552101 USGS 99 USGS99_780 July 1980 4,477.43 1.50

346 433503112400701 USGS 100 USGS100_780 July 1980 4,482.09 .37

347 433255112381801 USGS 101 USGS101_780 July 1980 4,481.62 3.30

348 433853112551601 USGS 102 USGS102_1291 Dec. 1991 4,478.61 3.30

349 432714112560701 USGS 103 USGS103_1280 Dec. 1980 4,426.71 1.50

350 432856112560801 USGS 104 USGS104_1280 Dec. 1980 4,431.94 1.50

351 432703113001801 USGS 105 USGS105_1180 Nov. 1980 4,426.29 1.50

352 432959112593101 USGS 106 USGS106_1180 Nov. 1980 4,428.19 1.50

353 432942112532801 USGS 107 USGS107_1180 Nov. 1980 4,438.48 3.30

354 432659112582601 USGS 108 USGS108_1280 Dec. 1980 4,426.00 1.50

355 432701113025601 USGS 109 USGS109_1180 Nov. 1980 4,423.92 1.50

356 432717112501501 USGS 110 USGS110_1080 Oct. 1980 4,429.91 9.20

357 433331112560501 USGS 111 USGS111_1091 Oct. 1991 4,455.51 9.20

358 433314112563001 USGS 112 USGS112_1091 Oct. 1991 4,456.21 3.30

359 433314112561801 USGS 113 USGS113_1091 Oct. 1991 4,456.88 9.20

360 433318112555001 USGS 114 USGS114_1091 Oct. 1991 4,456.50 9.20

361 433320112554101 USGS 115 USGS115_1091 Oct. 1991 4,456.31 3.30

362 433331112553201 USGS 116 USGS116_1091 Oct. 1991 4,456.76 3.30

363 432955113025901 USGS 117 USGS117_1091 Oct. 1991 4,427.62 3.30

364 432947113023001 USGS 118 USGS118_1192 Nov. 1992 4,425.98 3.30

365 432945113023401 USGS 119 USGS119_1091 Oct. 1991 4,426.89 3.30

366 432919113031501 USGS 120 USGS120_1291 Dec. 1991 4,425.72 3.30

Table G1. Water-level data used to represent 1980 steady-state head for the calibration of steady-state and transient models of 

groundwater flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

identifier used in this study. Observation name: Model observation name used in this study. Weighting statistic: Variance of the measurement error of head. 

Abbreviation: ft, foot]
Appendix G 207

Map 

No.

Site 

identifier

Local 

name

Observation 

name

Date 

measured

Observed head 

(ft)

 Weighting 

statistic (1/ft)

367 433450112560301 USGS 121 USGS121_1091 Oct. 1991 4,457.28 3.30

368 433353112555201 USGS 122 USGS122_1091 Oct. 1991 4,456.88 3.30

369 433352112561401 USGS 123 USGS123_1091 Oct. 1991 4,457.94 3.30

370 432307112583101 USGS 124 USGS124_499 Apr. 1999 4,420.85 9.20

371 432602113052801 USGS 125 USGS125_499 Apr. 1999 4,423.27 9.20

375 433445113202801 Weaver and Lowe WeavLow_585 May 1985 4,475.89 37.00

376 433716112563601 WS INEL 1 WSINEL1_1280 Dec. 1980 4,476.72 3.30

1

 Transient model only.

2

 Head estimated by extrapolation from March 2004.

3

 Steady-state model only.

Table G1. Water-level data used to represent 1980 steady-state head for the calibration of steady-state and transient models of 

groundwater flow, Idaho National Laboratory and vicinity, Idaho.—Continued

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

identifier used in this study. Observation name: Model observation name used in this study. Weighting statistic: Variance of the measurement error of head. 

Abbreviation: ft, foot]
208 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

This page intentionally left blank.
Appendix H 209

Appendix H. Water-Level Data Used for Calibration of 

Transient Model of Groundwater Flow, Idaho National 

Laboratory and Vicinity, Idaho
210 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table H1. Water-level data used for calibration of transient model of groundwater flow, Idaho National Laboratory and vicinity, Idaho.

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

used in this study. Observation name: Model observation name used in this study]

Map 

No.

Local 

name

Observation 

name

Date 

measured

Observed 

head

Number of 

observations

Initial 

simulated

date

Final observed 

and simulated 

date

1 2ND OWSLEY 2dOwsly_780 July 1980 4,561.62 74 12-31-1980 05-30-1995

2 434556 434556_491 04-08-1991 4,551.63 1 04-08-1991

3 434647 434647_491 04-03-1991 4,530.43 1 04-03-1991

4 434650 434650_880 1 Aug. 1980 4,513.64 2 12-31-1980 04-03-1991

5 434714 434714_1180 Nov. 1980 4,554.20 4 12-31-1980 04-13-1989

6 434726 434726_489 04-12-1989 4,539.22 2 04-12-1989 08-31-1989

7 434756 434756_686 06-03-1986 4,547.37 107 06-03-1986 11-08-1995

8 435026 435026_1180 Nov. 1980 4,562.86 3 12-31-1980 10-20-1981

9 435100 435100_1180 Nov. 1980 4,580.29 4 12-31-1980 08-31-1989

10 440109 440109_489 1 04-17-1989 4,587.49 2 04-17-1989 09-01-1989

12 ANL MW 11 ANLMW11_1292 12-17-1992 4,482.74 1 12-17-1992

13 ANL MW 13 ANLMW13_1196 Nov. 1996 4,485.00 1 12-31-1980

14 ANL OBS A 001 ANLOBSA_694 06-24-1994 4,482.84 1 06-24-1994

21 ANP 5 ANP5_780 July 1980 4,579.82 16 12-31-1980 05-22-1995

22 ANP 6 ANP6_780 July 1980 4,579.82 23 12-31-1980 06-15-1995

23 ANP 7 ANP7_780 July 1980 4,581.18 16 12-31-1980 05-22-1995

25 ANP 9 ANP9_1280 Dec. 1980 4,563.58 101 12-31-1980 10-10-1995

26 ANP 10 ANP10_780 July 1980 4,565.80 12 12-31-1980 05-23-1995

27 ANP DISP 3 ANPdsp3_784 07-19-1984 4,580.49 7 07-19-1984 12-08-1988

30 ARBOR TEST ArbTst_1280 Dec. 1980 4,485.52 107 12-31-1980 10-19-1995

31 AREA 2 Area2_780 July 1980 4,458.78 21 12-31-1980 07-14-1995

49 CERRO GRANDE CrGrnd_1280 Dec. 1980 4,426.37 98 12-31-1980 11-22-1995

51 CFA 2 CFA2_189 01-25-1989 4,457.15 1 01-25-1989

55 CFA LF 2-10 CFAL210_189 01-26-1989 4,456.53 8 01-26-1989 10-25-1995

56 CFA LF 2-11 CFAL211_1289 12-06-1989 4,459.32 2 12-06-1989 06-03-1994

59 CFA LF 3-9 CFALF39_1190 11-13-1990 4,455.98 5 11-13-1990 04-27-1995

63 COREHOLE 1 CrHle1_1280 Dec. 1980 4,435.74 90 12-31-1980 05-18-1995

65 COX WELL CoxWell_849 Aug. 1949 4,319.47 1 12-31-1980

69 CPP 4 CPP4_1083 10-17-1983 4,466.00 1 10-17-1983

69 CPP 5 CPP5_1193 11-30-1993 4,457.50 1 11-30-1993

74 DH 1B DH1B_785 1 07-19-1985 4,524.04 72 07-19-1985 11-16-1995

75 DH 2A DH2A_785 1 07-19-1985 4,522.57 25 07-19-1985 09-18-1995

83 ELLSWORTH Elswrth_567 May 1967 4,107.30 1 12-31-1980

88 FET DISP 3 FETdsp3_784 07-19-1984 4,581.26 11 07-19-1984 05-31-1995

90 FNGR BUTTE FngrBtt_1072 Oct. 1972 4,376.00 1 12-31-1980

91 GIN 1 (old) GIN1old_784 07-12-1984 4,578.75 3 07-12-1984 04-23-1993

91 GIN 1 (new) GIN1new_593 05-21-1993 4,576.21 3 05-21-1993 05-19-1995

92 GIN 2 GIN2old_780 01-02-1981 4,577.43 16 01-02-1981 05-21-1993

93 GIN 3 (old) GIN3old_784 07-12-1984 4,579.21 5 07-12-1984 04-23-1993

93 GIN 3 (new) GIN3new_594 05-26-1994 4,575.53 2 05-26-1994 05-19-1995
Appendix H 211

Map 

No.

Local 

name

Observation 

name

Date 

measured

Observed 

head

Number of 

observations

Initial 

simulated

date

Final observed 

and simulated 

date

94 GIN 4 GIN4_784 07-12-1984 4,579.20 6 07-12-1984 05-19-1995

95 GIN 5 (old) GIN5old_784 07-12-1984 4,579.28 5 07-12-1984 05-26-1994

95 GIN 5 (new) GIN5new_595 05-19-1995 4,574.33 1 05-19-1995

114 Houghland Hghlnd_380 Mar. 1980 4,379.85 1 12-31-1980

115 IET 1 DISP IETdisp_780 July 1980 4,580.32 24 12-31-1980 07-07-1995

121 ML 11 ML11_491 1 04-03-1991 4,534.45 2 04-03-1991 08-23-1992

122 ML 12 ML12_880 Dec. 1980 4,534.71 1 12-31-1980

123 ML 13 ML13_380 Mar. 1980 4,535.40 2 12-31-1980 04-04-1991

124 MTR TEST MTRtst_1280 Dec. 1980 4,457.62 167 12-31-1980 12-20-1995

128 NO NAME 1 NoName1_780 July 1980 4,577.82 25 12-31-1980 10-03-1995

129 NPR TEST NPRtst_784 07-26-1984 4,473.78 57 07-26-1984 10-23-1995

136 NRF 6 NRF6_991 09-09-1991 4,479.04 20 09-09-1991 11-07-1995

138 NRF 7 NRF7_991 09-10-1991 4,479.16 20 09-10-1991 11-08-1995

140 NRF 8 NRF8_895 08-04-1995 4,473.30 1 08-04-1995

141 NRF 9 NRF9_895 08-04-1995 4,472.11 1 08-04-1995

142 NRF 10 NRF10_895 08-04-1995 4,472.82 1 08-04-1995

143 NRF 11 NRF11_895 08-04-1995 4,472.23 1 08-04-1995

144 NRF 12 NRF12_895 08-04-1995 4,471.89 1 08-04-1995

145 NRF 13 NRF13_895 08-04-1995 4,477.80 1 08-04-1995

150 P&W 1 P&W1_780 July 1980 4,580.07 16 12-31-1980 05-19-1995

151 P&W 2 P&W2_780 July 1980 4,579.83 44 12-31-1980 10-18-1995

152 P&W 3 P&W3_780 July 1980 4,580.32 16 12-31-1980 05-31-1995

155 PSTF TEST PSTFtst_780 1 July 1980 4,578.32 25 12-31-1980 10-04-1995

170 QAB QAB_282 02-13-1982 4,424.48 8 02-13-1982 04-05-1988

184 RWMC M1SA WMCM1SA_1192 11-30-1992 4,425.56 7 11-30-1992 08-08-1995

185 RWMC M3S RWMCM3S_1192 11-30-1992 4,426.38 11 11-30-1992 09-05-1995

186 RWMC M4D RWMCM4D_1192 11-30-1992 4,427.19 8 11-30-1992 09-05-1995

187 RWMC M6S RWMCM6S_1192 11-30-1992 4,425.51 8 11-30-1992 09-05-1995

188 RWMC M7S RWMCM7S_1192 11-30-1992 4,426.97 11 11-30-1992 09-05-1995

196 SITE 1 Site1_1280 Dec. 1980 4,378.26 35 12-31-1980 09-21-1995

197 SITE 2 Site2_1280 Dec. 1980 4,158.31 35 12-31-1980 09-21-1995

199 SITE 6 Site6_780 July 1980 4,478.20 16 12-31-1980 06-01-1995

200 SITE 9 Site9_1280 Dec. 1980 4,453.49 95 12-31-1980 10-24-1995

201 SITE 14 Site14_1280 Dec. 1980 4,524.51 112 12-31-1980 10-18-1995

202 SITE 16 Site16_780 July 1980 4,484.84 24 12-31-1980 03-15-1995

203 SITE 17 Site17_780 July 1980 4,483.84 23 12-31-1980 06-16-1995

204 SITE 19 Site19_780 Dec. 1980 4,457.50 34 12-31-1980 07-06-1995

207 TAN 1 TAN1_1187a 11-06-1987 4,586.28 2 11-06-1987 11-17-1987

208 TAN 2 TAN2_1187a 11-06-1987 4,585.68 2 11-06-1987 11-17-1987

209 TAN 3 TAN3_190 01-24-1990 4,582.74 1 01-24-1990

Table H1. Water-level data used for calibration of transient model of groundwater flow, Idaho National Laboratory and vicinity, 

Idaho.—Continued

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

used in this study. Observation name: Model observation name used in this study]
212 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Map 

No.

Local 

name

Observation 

name

Date 

measured

Observed 

head

Number of 

observations

Initial 

simulated

date

Final observed 

and simulated 

date

210 TAN 5 TAN5_190 01-24-1990 4,582.33 1 01-24-1990

211 TAN 6 TAN6_990 09-09-1990 4,582.27 1 09-09-1990

212 TAN 7 TAN7_990 09-09-1990 4,582.19 1 09-09-1990

213 TAN 8 TAN8_190 01-24-1990 4,581.58 1 01-24-1990

214 TAN 9 TAN9_1289 12-11-1989 4,584.85 1 12-11-1989

216 TAN 10 A TAN10A_490 04-25-1990 4,586.51 1 04-25-1990

217 TAN 11 TAN11_1289 12-14-1989 4,584.96 1 12-14-1989

219 TAN 13 TAN13_1090 10-24-1990 4,580.57 1 10-24-1990

220 TAN 13A TAN13A_1190 11-29-1990 4,578.82 1 11-29-1990

221 TAN 14 TAN14_1090 10-24-1990 4,580.89 1 10-24-1990

222 TAN 15 TAN15_991 09-09-1991 4,580.99 1 09-09-1991

224 TAN 17 TAN17_80e 2 Dec. 1980 4,578.98 1 12-31-1980

225 TAN 18 TAN18_1192 11-03-1992 4,576.95 1 11-03-1992

226 TAN 19 TAN19_1092 10-14-1992 4,577.69 1 10-14-1992

227 TAN 20 TAN20_1092 10-14-1992 4,577.86 1 10-14-1992

228 TAN 21 TAN21_1092 10-14-1992 4,575.98 1 10-14-1992

229 TAN 22 TAN22_892 08-10-1992 4,579.05 1 08-10-1992

230 TAN 22A TAN22A_1092 10-14-1992 4,577.09 1 10-14-1992

231 TAN 23 TAN23_792 07-07-1992 4,578.76 1 07-07-1992

231 TAN 23A TAN23A_1092 10-14-1992 4,576.96 1 10-14-1992

232 TAN 24 TAN24_992 09-25-1992 4,576.61 1 09-25-1992

232 TAN 24A TAN24A_1092 10-14-1992 4,575.69 1 10-14-1992

233 TAN CH 1 TANCH1_190 01-24-1990 4,584.14 1 01-24-1990

234 TAN CH 2B TANCH2B_401 April 2001 4,577.41 1 12-31-1980

242 TRA 6 TRA6_1290 12-07-1990 4,455.60 1 12-07-1990

243 TRA 7 TRA7_990 09-28-1990 4,457.10 1 09-28-1990

244 TRA 8 TRA8_1290 12-19-1990 4,457.10 1 12-19-1990

245 TRA DISP TRAdisp_784 07-25-1984 4,463.36 30 07-25-1984 10-16-1995

247 USGS 1 USGS1_1280 Dec. 1980 4,435.21 190 12-31-1980 12-20-1995

248 USGS 2 USGS2_1280 Dec. 1980 4,466.83 96 12-31-1980 10-24-1995

250 USGS 4 USGS4_1280 Dec. 1980 4,531.61 100 12-31-1980 10-10-1995

251 USGS 5 USGS5_1280 July 1980 4,469.86 101 12-31-1980 10-25-1995

252 USGS 6 USGS6_1280 Dec. 1980 4,485.14 95 12-31-1980 10-24-1995

253 USGS 7 USGS7_1280 Dec. 1980 4,575.85 104 12-31-1980 10-04-1995

254 USGS 8 USGS8_1280 Dec. 1980 4,429.93 93 12-31-1980 10-12-1995

255 USGS 9 USGS9_1280 Dec. 1980 4,423.77 178 12-31-1980 12-20-1995

256 USGS 11 USGS11_1280 Dec. 1980 4,415.68 96 12-31-1980 10-26-1995

257 USGS 12 USGS12_1280 Dec. 1980 4,490.67 186 12-31-1980 12-28-1995

258 USGS 13 USGS13_781 07-11-1981 4,388.64 28 07-11-1981 04-10-1995

259 USGS 14 USGS14_1280 Dec. 1980 4,418.12 96 12-31-1980 10-26-1995

Table H1. Water-level data used for calibration of transient model of groundwater flow, Idaho National Laboratory and vicinity, 

Idaho.—Continued

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

used in this study. Observation name: Model observation name used in this study]
Appendix H 213

Map 

No.

Local 

name

Observation 

name

Date 

measured

Observed 

head

Number of 

observations

Initial 

simulated

date

Final observed 

and simulated 

date

260 USGS 15 USGS15_780 July 1980 4,492.56 43 12-31-1980 11-02-1995

262 USGS 17 USGS17_1280 Dec. 1980 4,478.38 110 12-31-1980 11-07-1995

263 USGS 18 USGS18_1280 Dec. 1980 4,533.62 103 12-31-1980 10-20-1995

264 USGS 19 USGS19_1280 Dec. 1980 4,527.93 183 12-31-1980 12-18-1995

265 USGS 20 USGS20_1280 Dec. 1980 4,453.86 98 12-31-1980 10-16-1995

266 USGS 21 USGS21_1280 Dec. 1980 4,506.06 179 12-31-1980 12-15-1995

267 USGS 22 USGS22_1280 Dec. 1980 4,438.13 97 12-31-1980 10-13-1995

268 USGS 23 USGS23_1280 Dec. 1980 4,484.31 98 12-31-1980 10-10-1995

269 USGS 24 USGS24_780 July 1980 4,579.49 104 12-31-1980 12-19-1995

270 USGS 25 USGS25_1280 Dec. 1980 4,579.07 184 12-31-1980 12-15-1995

271 USGS 26 USGS26_1280 Dec. 1980 4,579.21 99 12-31-1980 10-04-1995

272 USGS 27 USGS27_380 Mar. 1980 4,560.28 183 12-31-1980 12-21-1995

273 USGS 28 USGS28_780 July 1980 4,541.02 24 12-31-1980 04-24-1995

274 USGS 29 USGS29_780 July 1980 4,522.48 29 12-31-1980 06-15-1995

275 USGS 30A USGS30A_1280 Dec. 1980 4,537.16 96 12-31-1980 11-21-1995

275 USGS 30B USGS30B_1280 Dec. 1980 4,528.16 96 12-31-1980 11-21-1995

275 USGS 30C GS30C_1280 Dec. 1980 4,526.07 97 12-31-1980 11-21-1995

276 USGS 31 USGS31_780 July 1980 4,529.69 27 12-31-1980 06-15-1995

277 USGS 32 USGS32_780 July 1980 4,522.28 28 12-31-1980 06-15-1995

279 USGS 34 USGS34_780 July 1980 4,456.43 34 12-31-1980 10-11-1995

280 USGS 35 USGS35_780 July 1980 4,456.25 34 12-31-1980 10-16-1995

281 USGS 36 USGS36_780 July 1980 4,456.53 39 12-31-1980 10-11-1995

282 USGS 37 USGS37_1280 Dec. 1980 4,456.26 92 12-31-1980 10-11-1995

283 USGS 38 GS38new_780 July 1980 4,456.59 33 12-31-1980 10-12-1995

284 USGS 39 USGS39_780 July 1980 4,456.45 39 12-31-1980 10-10-1995

285 USGS 40 GS40nw_1280 Dec. 1980 4,457.25 141 12-31-1980 10-19-1995

286 USGS 41 USGS41_780 July 1980 4,457.68 35 12-31-1980 10-19-1995

287 USGS 42 USGS42_780 July 1980 4,457.64 35 12-31-1980 10-19-1995

288 USGS 43 USGS43_780 July 1980 4,457.64 35 12-31-1980 11-13-1995

289 USGS 44 USGS44_780 July 1980 4,457.76 34 12-31-1980 10-16-1995

290 USGS 45 USGS45_780 July 1980 4,456.81 34 12-31-1980 10-11-1995

291 USGS 46 USGS46_1280 Dec. 1980 4,457.62 77 12-31-1980 10-16-1995

292 USGS 47 USGS47_780 July 1980 4,458.45 48 12-31-1980 10-16-1995

293 USGS 48 USGS48_780 July 1980 4,457.81 32 12-31-1980 10-16-1995

294 USGS 49 GS49new_1186 11-14-1986 4,460.00 11 11-14-1986 04-27-1992

296 USGS 51 USGS51_780 July 1980 4,457.79 34 12-31-1980 10-24-1995

297 USGS 52 USGS52_780 July 1980 4,457.81 33 12-31-1980 10-19-1995

302 USGS 57 USGS57_780 July 1980 4,456.42 51 12-31-1980 10-11-1995

303 USGS 58 USGS58_1280 Dec. 1980 4,457.61 135 12-31-1980 10-30-1995

304 USGS 59 USGS59_780 July 1980 4,457.49 32 12-31-1980 10-23-1995

Table H1. Water-level data used for calibration of transient model of groundwater flow, Idaho National Laboratory and vicinity, 

Idaho.—Continued

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

used in this study. Observation name: Model observation name used in this study]
214 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Map 

No.

Local 

name

Observation 

name

Date 

measured

Observed 

head

Number of 

observations

Initial 

simulated

date

Final observed 

and simulated 

date

310 USGS 65 USGS65_780 July 1980 4,458.28 50 12-31-1980 10-11-1995

312 USGS 67 USGS67_780 Dec. 1980 4,457.19 27 12-31-1980 10-17-1995

321 USGS 76 USGS76_780 July 1980 4,456.79 40 12-31-1980 10-30-1995

322 USGS 77 USGS77_380 July 1980 4,456.95 32 12-31-1980 10-24-1995

324 USGS 79 USGS79_780 July 1980 4,457.40 69 12-31-1980 10-30-1995

327 USGS 82 USGS82_1280 Dec. 1980 4,457.37 88 12-31-1980 10-17-1995

328 USGS 83 USGS83_1280 Dec. 1980 4,442.82 98 12-31-1980 10-26-1995

329 USGS 84 USGS84_1280 Dec. 1980 4,456.35 86 12-31-1980 10-18-1995

330 USGS 85 (old) GS85old_1280 Dec. 1980 4,456.00 89 12-31-1980 04-19-1993

330 USGS 85 (new) GS85new_793 07-28-1993 4,453.39 10 07-28-1993 10-23-1995

331 USGS 86 USGS86_1280 Dec. 1980 4,428.72 98 12-31-1980 10-12-1995

332 USGS 87 USGS87_1080 Oct. 1980 4,430.13 107 12-31-1980 10-16-1995

334 USGS 89 USGS89_1080 Oct. 1980 4,429.24 110 12-31-1980 10-25-1995

335 USGS 90 USGS90_1080 Oct. 1980 4,427.83 98 12-31-1980 10-25-1995

343 USGS 97 USGS97_1280 Dec. 1980 4,477.95 162 12-31-1980 12-26-1995

344 USGS 98 USGS98_780 July 1980 4,472.15 62 12-31-1980 11-06-1995

345 USGS 99 USGS99_780 July 1980 4,477.43 58 12-31-1980 11-06-1995

346 USGS 100 USGS100_780 July 1980 4,482.09 52 12-31-1980 10-19-1995

347 USGS 101 USGS101_780 July 1980 4,481.62 24 12-31-1980 10-19-1995

348 USGS 102 GS102_1289 12-20-1989 4,482.56 35 12-20-1989 11-07-1995

349 USGS 103 USGS103_1280 Dec. 1980 4,426.71 74 12-31-1980 10-10-1995

350 USGS 104 USGS104_1280 Dec. 1980 4,431.94 54 12-31-1980 10-10-1995

351 USGS 105 USGS105_1180 Nov. 1980 4,426.29 41 12-31-1980 10-10-1995

352 USGS 106 GS106_1180 Nov. 1980 4,428.19 90 12-31-1980 10-10-1995

353 USGS 107 USGS107_1180 Nov. 1980 4,438.48 82 12-31-1980 10-26-1995

354 USGS 108 USGS108_1280 Dec. 1980 4,426.00 41 12-31-1980 10-10-1995

355 USGS 109 GS109_1180 Nov. 1980 4,423.92 65 12-31-1980 10-12-1995

356 USGS 110 USGS110_1080 Oct. 1980 4,429.91 70 12-31-1980 04-01-1992

356 USGS 110A GS110A_1095 10-25-1995 4,433.80 1 10-25-1995

357 USGS 111 USGS111_884 08-31-1984 4,464.26 38 08-31-1984 10-26-1995

358 USGS 112 USGS112_785 07-06-1985 4,463.87 43 07-06-1985 10-11-1995

359 USGS 113 USGS113_785 07-06-1985 4,464.87 40 07-06-1985 10-17-1995

360 USGS 114 USGS114_785 07-06-1985 4,463.58 40 07-06-1985 10-25-1995

361 USGS 115 USGS115_785 07-06-1985 4,463.41 42 07-06-1985 10-23-1995

362 USGS 116 USGS116_785 07-06-1985 4,464.33 39 07-06-1985 10-17-1995

363 USGS 117 USGS117_1287 12-08-1987 4,432.23 45 12-08-1987 10-24-1995

364 USGS 118 USGS118_1192 11-30-1992 4,425.98 13 11-30-1992 11-22-1995

365 USGS 119 USGS119_1287 12-08-1987 4,431.89 37 12-08-1987 10-25-1995

366 USGS 120 GS120_1287 12-08-1987 4,429.81 94 12-08-1987 12-20-1995

367 USGS 121 USGS121_191 01-29-1991 4,458.67 14 01-29-1991 10-30-1995

Table H1. Water-level data used for calibration of transient model of groundwater flow, Idaho National Laboratory and vicinity, 

Idaho.—Continued

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

used in this study. Observation name: Model observation name used in this study]
Appendix H 215

Map 

No.

Local 

name

Observation 

name

Date 

measured

Observed 

head

Number of 

observations

Initial 

simulated

date

Final observed 

and simulated 

date

368 USGS 122 USGS122_191 01-29-1991 4,458.30 12 01-29-1991 10-30-1995

369 USGS 123 USGS123_191 01-29-1991 4,458.15 13 01-29-1991 10-30-1995

370 USGS 124 USGS124_194 01-27-1994 4,418.84 7 01-27-1994 10-26-1995

371 USGS 125 USGS125_495 04-27-1995 4,419.84 3 04-27-1995 10-26-1995

375 Weaver and Lowe WeavLow_485 04-15-1985 4,475.23 2 04-15-1985 05-23-1985

376 WS INEL 1 WSINEL1_1280 Dec. 1980 4,476.72 46 12-31-1980 11-06-1995

1

 Head observations only.

2

 Head estimated by extrapolation from March 2004.

Table H1. Water-level data used for calibration of transient model of groundwater flow, Idaho National Laboratory and vicinity, 

Idaho.—Continued

[Map No.: Identifier used to locate wells on maps located in appendix B figures and as a cross reference with data in other appendixes. Local name: Local well 

used in this study. Observation name: Model observation name used in this study]
216 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

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Appendix I 217

Appendix I. Tritium Disposal and Production Well Pumpage 

at Idaho Nuclear Technology and Engineering Center and 

Reactor Technology Complex, Idaho National Laboratory, 

Idaho
218 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

Table I1. Tritium disposal and production well pumpage at the Idaho Nuclear Technology and Engineering Center and 

the Reactor Technology Complex, 1952 through 1968, Idaho National Laboratory, Idaho.

[Data from references as indicated at end of table. Abbreviations: INTEC, Idaho Nuclear Technology and Engineering Center; RTC, 

Reactor Technology Complex; ft3/s, cubic foot per second; na, data not available; –, no waste disposed]

Year

Tritium disposal at INTEC and RTC, 1952 through 1968

INTEC disposal well (CPP 3) INTEC disposal pit RTC warm-waste ponds

Discharge rates 

(ft3

/s)

Total tritium 

(Curies)

Discharge rates 

(ft3/s)

Total tritium 

(Curies)

Discharge rates 

(ft3/s)

Total tritium 

(Curies)

1952 – – – – 10.021 1,27

1953 31.679 4456 – – 1.064 220

1954 3.971 4608 30.021 na 1.403 2105

1955 31.679 4808 3.021 na 5.414 2114

1956 31.488 41,543 3.025 na 5.402 277

1957 3.979 4969 3.021 na 5.437 289

1958 31.157 43,504 3.030 na 51.056 2278

1959 31.390 42,565 3.034 na 3.837 2444

1960 3.805 4679 3.008 na 3.932 2308

1961 3.797 6578 3.000 7,812 3.986 8303

1962 31.111 8146 3.020 8194.4 31.195 8278

1963 31.089 81,021 3.011 858.2 3.841 8386

1964 31.458 81,696 3.006 872.5 3.713 8399

1965 31.763 958 3.003 937.9 3.713 9328

1966 31.543 10234 3.002 1015.5 3.546 10389

1967 31.276 11857 – – 3.754 11402

1968 31.149 12510 – – 3.784 12499

Production well pumpages at INTEC and RTC, 1952 through 1968

INTEC well pumpages (ft3

/s) RTC well pumpages (ft3/s)

Year CPP 1 CPP 2 TRA 1 TRA 2 TRA 3 TRA 4

1952 – – na na – –

1953 na na na na – –

1954 na na na na – –

1955 na na na na – –

1956 na na na na – –

1957 na na na na na –

1958 na na na na na –

1959 130.444 130.931 130.584 130.520 131.599 –

1960 13.504 13.696 131.123 13.383 131.237 –

1961 13.659 13.644 132.311 13.128 13.492 –

1962 13.919 13.726 131.962 13.064 13.980 –

1963 13.751 13.637 131.221 13.001 131.570 na

1964 13.726 13.800 131.134 13.000 131.719 na

1965 na na na – na na

1966 na na na – na na

1967 na na na – na na

1968 na na na – na na
Appendix I 219

Table I1. Tritium disposal and production well pumpage at the Idaho Nuclear Technology and Engineering Center and the Reactor 

Technology Complex, 1952 through 1968, Idaho National Laboratory, Idaho.—Continued

[Data from references as indicated at end of table. Abbreviations: IDO, Idaho Operations Office; INTEC, Idaho Nuclear Technology and Engineering Center; 

RTC, Reactor Technology Complex; ft3/s, cubic foot per second; na, data not available; –, no waste disposed]

References

1 Schmalz, B.L., 1972, Radionuclide distribution in soil mantle of the lithosphere as a consequence of waste disposal at the 

National Reactor Testing station: U.S. Atomic Energy Commission, Idaho Operations Office Publication IDO-10049, 80 p.

2 Barraclough, J.T., Teasdale, W.E., Robertson, J.B., and Jensen, R.G., 1967, Hydrology of the National Reactor Testing Station, 

Idaho, 1966: U.S. Geological Survey Open-File Report, (IDO-22049), 95. p.

3 Robertson, J.B., Schoen, R., 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.

4 DOE-ID, retrieved May 4, 1989, Radioactive waste management information system nondecay summary database list 

(P61SH050) list for 1954-1974: FOIA Document No. 0007, RWM-167, 1 p.

5 U.S. Atomic Energy Commission, 1972, U.S. Atomic Energy Commission, Idaho Operations Office, National Reactor Testing 

Station Radioactive Waste Management Information, 1972, Summary and Record-to-Date: U.S. Atomic Energy Comission, 

Idaho Operations Office Publication IDO-10054(72), 13 p.

6 Schmalz, B.L., and Keys, W.S., 1962, Retention and migration of radioactive isotopes in the lithosphere at the National Reactor 

Testing Station – Idaho: U.S. Atomic Energy Commission, Waste Management Section, Idaho Operations Office Publication 

IDO-12026, 26 p.

7 Lewis, B.D., Eagleton, J.M., and Jensen, R.G., 1985, Aqueous radioactive- and industrial-waste disposal at the Idaho National 

Engineering Laboratory through 1982: U.S. Geological Open-File Report 85-636, (DOE/ID-22069), 77 p.

8 Osloond, J.H., 1965, Radioactive waste disposal data for the National Reactor Testing Station: U.S. Atomic Energy 

Commission, Idaho Operations Office Publication IDO-12040, 29 p.

9 Osloond, J.H., and Schmalz, B.L., 1966, Radioactive waste disposal data for the National Reactor Testing Station, Idaho: U.S. 

Atomic Energy Commission, Idaho Operations Office Publication IDO-12040-S1, 12 p.

10 Osloond, J.H., 1967, Radioactive waste disposal data for the National Reactor Testing Station, Idaho: U.S. Atomic Energy 

Commission, Idaho Operations Office Publication IDO-12040-S2, 18 p.

11 Osloond, J.H., and Newcomb, D.L., 1968, Radioactive waste disposal data for the National Reactor Testing Station, Idaho: U.S. 

Atomic Energy Commission, Idaho Operations Office Publication IDO-12040-S3, 15 p.

12 Osloond, J.H., and Newcomb, D.L., 1969, Radioactive waste disposal data for the National Reactor Testing Station, Idaho: U.S. 

Atomic Energy Commission, Idaho Falls, Idaho, (IDO-12040-S4), 15 p.

13 Morris, D.A., Barraclough, J.T., Chase, G.H., Teasdale, W.E., and Jensen, R.G., 1965, Hydrology of subsurface waste disposal 

National Reactor Testing Station Idaho annual progress report: U.S. Atomic Energy Commission, Idaho Falls, Idaho, (IDO22047), [variously paged].
220 Steady-State and Transient Models, Eastern Snake River Plain Aquifer, Idaho National Laboratory and Vicinity, Idaho

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Publishing support provided by the U.S. Geological Survey

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
Ackerman and others— Steady-State and Transient Models, Groundwater Flow and Transport, Idaho National Laboratory, Idaho—Scientific Investigations Report 2010–5123