GEOHYDROLOGY AND SIMULATION OF GROUNDWATER FLOW NEAR LOS ALAMOS, NORTH-CENTRAL

NEW MEXICO

By Peter F. Frenzel

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 95-4091

Prepared in cooperation with 

LOS ALAMOS NATIONAL LABORATORY

Albuquerque, New Mexico 

1995
U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

Gordon P. Eaton, Director

For additional information 

write to:

District Chief

U.S. Geological Survey

Water Resources Division

4501 Indian School Rd. NE, Suite 200

Albuquerque, New Mexico 87110

Copies of this report can 

be purchased from:

U.S. Geological Survey

Earth Science Information Center

Open-File Reports Section

Box 25286, MS 517

Denver Federal Center

Denver, Colorado 80225
CONTENTS

Page

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

mtroduction....................................................................................................................................^ 2

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

Location of the study area......................................................................................................... 2

Well-numbering system ............................................................................................................ 5

Acknowledgments..................................................................................................................... 6

Geohydrology....................................................................................................................................... 6

Espanola Basin............................................................................................................................ 6

Los Alamos area ......................................................................................................................... 12

Ground-water flow, recharge, and discharge ........................................................................ 18

Ground-water withdrawals and changes in recharge .......................................................... 20

Simulation of ground-water flow ...................................................................................................... 24

Description of the model and modifications to the McAda-Wasiolek model.................... 24

Model grid ......................................................................................................................... 24

Hydraulic conductivity, transmissivity, and leakance ................................................ 25

Specific yield and storage coefficients ........................................................................... 32

Initial condition and time periods ................................................................................. 32

Boundary conditions ....................................................................................................... 32

Constant ground-water recharge and discharge ............................................... 33

Variable ground-water withdrawals and recharge............................................. 35

Other modifications.......................................................................................................... 36

Model budget.................................................................................................................... 36

Model adjustments .................................................................................................................... 39

System properties used for comparison ....................................................................... 39

System properties adjusted............................................................................................. 51

Recharge ........................................................................................................ 51

Hydraulic conductivity near Los Alamos ........................................................... 52

Specific yield and storage ...................................................................................... 52

Simulated response to projected withdrawals....................................................................... 54

Sensitivity tests ........................................................................................................................... 55

Pajarito Fault Zone recharge ........................................................................................... 56

Hydraulic conductivity ................................................................................................... 57

Storage ............................................................................................................................... 61

Predictive capability .................................................................................................................. 65

Data needs for an improved understanding of the flow system................................................... 68

Summary and conclusions ................................................................................................................. 69

References ............................................................................................................................................. 71

Supplemental information.................................................................................................................. 73

in
FIGURES

Page

Figure 1. Map showing location of the study area in north-central New Mexico..................... 3

2. Map showing location of major well fields and selected streamflow-gaging

stations in the study area, north-central New Mexico ............................................. 4

3. Diagram showing system of numbering wells based on the Federal

land-survey system ....................................................................................................... 5

4-6. Maps showing:

4. Major tectonic features of north-central New Mexico ........................................... 7

5. General geology of the study area, north-central New Mexico............................. 8

6. Predevelopment potentiometric surface in the upper part of the Tesuque

aquifer system, north-central New Mexico ......................................................... 10

7. Fence diagram of the Pajarito Plateau, north-central New Mexico............................. 13

8. Graphs showing ground-water withdrawals from well fields and estimated 

withdrawals from individual wells in the Espanola Basin, north-central New 

Mexico.............................................................................................................................. 21

9. Map showing horizontal model grid and extent of layers........................................... 26

10. Diagrammatic section along model row 9 showing model layers and subsurface

geology............................................................................................................................. 27

11-17. Maps showing:

11. Hydraulic-conductivity values for layers 1-3........................................................... 29

12. Hydraulic-conductivity values for layers 4 and 5................................................... 30

13. Boundary conditions represented in layer 1 of the model..................................... 31

14. Distribution of areal recharge in the model, in inches per year............................ 34

15. Model-derived potentiometric surface for layer 1 and measured hydraulic

heads for 1977........................................................................................................... 40

16. Model-derived potentiometric surface for layer 1 and measured hydraulic

heads for 1993........................................................................................................... 41

17. Location of wells having hydrographs..................................................................... 43

18-22. Hydrographs for wells in the:

18. Los Alamos well field, north-central New Mexico.................................................. 44

19. Guaje well field, north-central New Mexico............................................................ 45

20. Pajarito Mesa well field, north-central New Mexico............................................... 46

21. Buckman well field, north-central New Mexico...................................................... 48

22. Santa Fe area, north-central New Mexico................................................................. 49

23. Map showing steady-state potentiometric surface for layer 1..................................... 53

IV
FIGURES-Conduded

Page

Figures 24-31. Hydrographs showing effect of:

24. Moving specified-flow recharge of the Pajarito Fault Zone from layer 1

to layer 4......................................................................................................... 58

25. Moving specified-flow recharge of the Pajarito Fault Zone from layer 1

to layer 4, using larger flow values............................................................. 59

26. Using smaller horizontal hydraulic-conductivity values in the

northwestern part of the model................................................................... 60

27. Using larger horizontal hydraulic-conductivity values in the

northwestern part of the model.................................................................. 62

28. Using smaller vertical hydraulic-conductivity values................................... 63

29. Using larger vertical hydraulic-conductivity values...................................... 64

30. Using smaller storage values............................................................................. 66

31. Using larger storage values................................................................................ 67

TABLES

Table 1. Estimated horizontal hydraulic conductivity in Los Alamos National Laboratory

production and selected test wells................................................................................. 14

2. Model budget.......................................................................................................................... 37

3. Model budget items that change with time........................................................................ 38

4. Average of differences between measured and model-derived hydraulic heads

for the standard and each sensitivity test, in feet........................................................ 56

5. Constant-flow-boundary recharge rates, in cubic feet per second.................................. 74

6. Specified discharge from Los Alamos wells, in cubic feet per second............................ 76

7. Specified discharge from Guaje wells, in cubic feet per second...................................... 78

8. Specified discharge from Pajarito Mesa and Otowi wells, in cubic feet per second..... 80

9. Specified discharge from Buckman wells, in cubic feet per second................................ 81

10. Specified discharge from Santa Fe wells, in cubic feet per second.................................. 82

11. Percentage of public-supply well pumpage assigned to each model layer................... 84

12. Specified discharge from domestic and industrial wells, in cubic feet per second....... 85

13. Difference between measured and model-derived hydraulic heads, in feet................. 86
CONVERSION FACTORS AND VERTICAL DATUM

Multiply By To obtain

inch 25.4 millimeter

foot 0.3048 meter

mile 1.609 kilometer

acre 4,047 square meter

square mile 2.590 square kilometer

cubic foot 0.02832 cubic meter

7.48 gallons

acre-foot 0.001233 cubic hectometer

43,560 cubic feet

per foot 3.281 per meter

foot per day 0.3048 meter per day

foot per mile 0.1894 meter per kilometer

foot squared per day 0.09290 meter squared per day

cubic foot per second 0.02832 cubic meter per second

448.8 gallons per minute

acre-foot per year 0.0013803 cubic foot per second

0.6184 gallon per minute

gallon per minute 0.06309 liter per second

0.002228 cubic foot per second

billion gallons per year 4.2361 cubic feet per second

Temperature in degrees Celsius (°C) can be converted to degrees Fahrenheit (°F) by the 

equation:

°F = 9/5(°C) + 32

Sea level: In this report "sea level" refers to the National Geodetic Vertical Datum of 1929 

a geodetic datum derived from a general adjustment of the first-order level nets of the United 

States and Canada, formerly called Sea Level Datum of 1929.

VI
GEOHYDROLOGY AND SIMULATION OF GROUND-WATER FLOW 

NEAR LOS ALAMOS, NORTH-CENTRAL NEW MEXICO

By Peter F. Frenzel

ABSTRACT

An existing model was modified in recognition of new geohydrologic interpretations and 

adjusted to simulate hydrographs in well fields in the Los Alamos area. Hydraulic-head 

drawdowns at the Buckman well field resulting from two projected ground-water-withdrawal 

alternatives were estimated with the modified model.

The Chaquehui formation (informal usage) is the main new feature of recent hydrologic 

interpretations for the Los Alamos area. The Chaquehui occupies a "channel" that was eroded or 

faulted into the Tesuque Formation, and the Chaquehui is more permeable than the Tesuque. 

The Chaquehui is a major producing zone in the Pajarito Mesa well field and to a lesser extent in 

the Guaje well field.

Model modification included splitting the four layers of the McAda-Wasiolek model 

(McAda, D.P., and Wasiolek, Maryann, 1988, Simulation of the regional geohydrology of the 

Tesuque aquifer system near Santa Fe, New Mexico: U.S. Geological Survey Water-Resources 

Investigations Report 87-4056, 71 p.) into eight layers to better simulate vertical ground-water 

movement. Other model modifications were limited as much as possible to the area of interest 

near Los Alamos and consisted mainly of adjusting hydraulic-conductivity values representing 

the Tesuque Formation, Chaquehui formation (informal usage), and Puye Formation, and 

adjusting simulated recharge along the Pajarito Fault Zone west of Los Alamos. Adjustments 

were based mainly on simulation of fluctuations in measured hydraulic heads near Los Alamos.

Two possible alternative plans for replacing Guaje well field production were suggested by 

Los Alamos National Laboratory. In the first plan (Guaje alternative), the Guaje field would be 

renewed with four new wells replacing the existing production wells in the Guaje field. In the 

second plan (Pajarito-Otowi alternative), the Guaje well field would be retired and its former 

production would be made up by additional withdrawals from the Pajarito Mesa and Otowi well 

fields. A projection for each of these alternatives was made through 2012 using the new eightlayer model. In the Guaje field, projected hydraulic heads at the end of 2012 were as much as 50 

feet lower with the Guaje alternative; in the Pajarito Mesa field, hydraulic heads were as much as 

12 feet higher with the Guaje alternative. At the western end of the Los Alamos well field, 

projected hydraulic heads were about 20 feet higher with the Guaje alternative; at the eastern end 

of the Los Alamos field, the difference between alternatives was much less. At the Buckman field, 

projected hydraulic heads were about 2 feet higher with the Guaje alternative because the 

Buckman field is closer to the Pajarito Mesa field than to the Guaje field.

Ways of improving the understanding of the flow system include developing a more 

accurate representation of the structure and extent of the Tesuque Formation, Chaquehui 

formation, and Puye Formation of the Santa Fe Group and obtaining more detailed geologic and 

hydrologic data for the Chaquehui and Puye. Data that describe water chemistry, hydraulic 

head, and degree of saturation would be valuable for determining the location and quantity of 

recharge on the Pajarito Plateau, especially along the west side of the Plateau and in canyon 

bottoms. Chloride concentrations in soil at the top of the Bandelier Tuff could be used to verify 

the concept that evapotranspiration accounts for nearly all precipitation over a large area of the 

plateau.

1
INTRODUCTION

Los Alamos National Laboratory (LANL) and the communities of Los Alamos and White 

Rock, New Mexico, obtain their water primarily from wells drilled into the Puye Formation, 

Chaquehui formation (informal usage of Purtymun, 1995), and Tesuque Formation of the Santa 

Fe Group. Because the old wells in the Guaje well field have become unserviceable they are to be 

replaced or the well field is to be abandoned. If the field is abandoned, additional ground water 

could be withdrawn from the Pajarito Mesa and Otowi well fields. The relative effects of these 

two courses of action on hydraulic heads in the Buckman well field, which supplies water to the 

City of Santa Fe, are also of interest. Additionally, a better understanding of the geohydrologic 

system in the area near Los Alamos would be desirable to address general environmental 

concerns, including resource depletion and contaminant transport. In response to these concerns, 

the U.S. Geological Survey, in cooperation with LANL, an agent of the Department of Energy, 

conducted a study to evaluate the effects of replacing or abandoning the Guaje wells and to 

improve the understanding of the geohydrologic system.

Purpose and Scope

The purposes of this report are to present recent geohydrologic interpretations for the Los 

Alamos area, a ground-water flow model modified on the basis of those interpretations, 

estimated hydraulic-head drawdowns at the Buckman well field resulting from two projected 

ground-water-withdrawal alternatives, and to suggest additional geohydrologic information. 

The McAda and Wasiolek (1988) model of the Tesuque aquifer system in the Espanola Basin was 

modified, and modifications were limited as much as possible to the area of interest near Los 

Alamos. Drawdown estimates were made using the modified model. One projected alternative, 

here called the "Guaje alternative," is to continue withdrawals from a renewed Guaje well field 

using four replacement wells in the same field. The other alternative, here called the "PajaritoOtowi alternative," is to retire the Guaje field and increase withdrawals from the Pajarito Mesa 

and Otowi well fields. Additional hydrologic information would be needed to model groundwater flow paths with the necessary detail.

Location of the Study Area

The study area is the same as that of McAda and Wasiolek (1988) and includes 

approximately 700 square miles of the Espanola Basin in north-central New Mexico in the 

eastern part of Los Alamos County, northwestern part of Santa Fe County, and small parts of Rio 

Arriba and Sandoval Counties (fig. 1). The area of specific interest for this report is the vicinity of 

the well fields that supply Los Alamos and the Buckman well field, which partially supplies 

Santa Fe. Although the area of interest is limited, a larger area of the Espanola Basin was 

simulated to minimize boundary effects.

Six well fields are in the model area (fig. 2). The Buckman and Santa Fe well fields supply 

water to Santa Fe. The Guaje, Los Alamos, and Pajarito Mesa well fields supply water to Los 

Alamos. The Otowi well field, consisting of two wells, is the newest and was added to the Los 

Alamos supply system in 1993.
8 KILOMETERS

Figure 1.-Location of the study area in north-central New Mexico 

(modified from McAda and Wasiolek, 1988, fig.1).
106'15' 106'00'

ESPANOL.A 

* CAHVOH

\-».WEL±T~ *~7r^r*~^r~-~. 3i.NTA FE COUNTY ! 

FIELD G-5

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p u e »i, o \

(

SANTA 

MUNICIPAL ^L 

AIRP

SANTA 

.DOWNS

T.

20 

N.

T. 

19 

N.

T. 

18 

N.

T. 

17 

N.

T. 

16 

N.

T. 

15 

N.

R. 6 E. R. 7 E. R. 8 E R. 9 E. R. 10 E.

01234 5 MILES

I I '. i I '. ' ' 

01 2345 KILOMETERS

Santa Fe EXPLANATION

WELL AND WELL NAME

STREAM FLOW-GAGING STATION 

NUMBER 08313000

A

^

STREAMFLOW-GAGING STATION 

NUMBER 08314500 (discontinued)

Figure 2. Location of major well fields and selected streamflow-gaging stations in the study

area, north-central New Mexico (modified from McAda and Wasiolek, 1988, fig. 2).

4
Well-Numbering System

The system of numbering wells in this report is based on the common subdivision of land 

into townships, ranges, and sections in the Federal land-survey system. The well numbers based 

on this system consist of rour parts separated by periods (fig. 3). The first part is the township 

number, the second part is the range number, and the third part is the section number. Because 

all township blocks within the study area are north of the base line and east of the principal 

meridian, the letters N and E, indicating direction, are omitted as well as the letters T and R for 

township and range. Hence, the number 18.7.1 is assigned to any well located in sec. 1, T. 18 N., 

R.7E.

The fourth part of the number consists of three digits that denote the particular 10-acre tract 

within the section in which the well is located. The method of numbering the tracts within the 

section is shown in figure 3. For this purpose the section is divided into four quarters, numbered 

1,2,3, and 4, in the normal reading order, for the northwest, northeast, southwest, and southeast 

quarters, respectively. The first digit of the fourth part gives the quarter section, which is a tract 

of 160 acres. Each quarter is subdivided in the same manner so that the first and second digits 

together define the 40-acre tract. Finally, the 40-acre tract is divided into four 10-acre tracts, and 

the third digit denotes the 10-acre tract. Thus, well 18.7.1.224 is in the SE1/4 of the NE1/4 of the 

NE1/4 of sec. 1, T. 18 N., R. 7 E.

LANL wells are identified by name. The names are the same as those used in LANL reports 

(such as Purtymun, 1984; Purtymun and others, 1985; and Stoker and others, 1992).

WELL 18.7.1.224 

Figure 3.--System of numbering wells based on the Federal land-survey system.
Acknowledgments

This study benefitted greatly from the geohydrologic concepts of Bill Purtymun, Alan 

Stoker, Steve McLin, and Bruce Gallaher of Los Alamos National Laboratory. These individuals 

also made available much of the literature used in this study and provided well completion, 

water-level, and pumping records for the LANL wells. The author would also like to thank Tom 

Morrison, Charles Wohlenberg, Nancy Cunningham, and Dave Esparza of the New Mexico State 

Engineer Office and Robert Jorgensen of the Sangre de Cristo Water Company for making 

available well-completion and pumping records.

GEOHYDROLOGY

The area of the McAda-Wasiolek (1988) model includes the southern two-thirds of the 

Espanola Basin (fig. 4), which is one of a series of structural basins along the Rio Grande Rift of 

Colorado, New Mexico, and Texas. "The Espanola Basin is a north- to northwest-trending and 

plunging, asymmetric faulted synclinal sag * * *, filled to an unknown depth with 

semiconsolidated to unconsolidated Tertiary and Quaternary sediments'' (McAda and Wasiolek, 

1988, p. 7). Precambrian rocks crop out east of the basin in the Sangre de Cristo Mountains 

(fig. 5). On the west, the Jemez Mountains are composed of Quaternary and Tertiary volcanics.

The Tesuque aquifer system in the Espanola Basin is composed mainly of the Tesuque 

Formation, but also includes the Chaquehui formation (informal usage of Purtymun, 1995), and 

the Puye and Ancha Formations of the Santa Fe Group. The predevelopment potentiometric 

surface for the upper part of the Tesuque aquifer system (fig. 6) was constructed by McAda and 

Wasiolek (1988) from maps of six previous works and is thought to represent mainly the water 

table. The predevelopment potentiometric surface is highest on the east and west sides of the 

basin and lowest where the Rio Grande exits on the southwest, indicating that ground water 

generally flows from the east and west to the Rio Grande. The following sections briefly describe 

the geohydrology of the Espanola Basin in general, then continue with a more detailed summary 

of the part of the basin near Los Alamos.

Espanola Basin

Detailed descriptions of the geology of the Espanola Basin have been reported in previous 

studies (Spiegel and Baldwin, 1963; Griggs, 1964; Galusha and Blick, 1971; Baltz, 1978; Kelley, 

1978; Manley, 1978a, 1978b). The geologic setting of the Espanola Basin was summarized by 

McAda and Wasiolek (1988, p. 7).

The Espanola Basin (fig. 4) is defined by Mesozoic or older bedrock highs on all sides. On 

the northwest a series of faults dropped downward on the southeast separates the Espanola 

Basin from the Mesozoic rocks of the Chama Basin. To the north is the Brazos Uplift. On the 

northeast, the Rio Grande enters the Espanola Basin from the San Luis Basin through the 

Embudo Channel, a bedrock constriction. On the east are the Picuris Block, the Sangre de Cristo 

Uplift, and the Santa Fe Block, where principal outcrops are of Precambrian rocks. To the 

southeast a northwest-plunging syncline in Mesozoic and older bedrock limits the extent of the 

Espanola Basin. To the south is the Cerrillos Uplift and La Bajada Fault. The Rio Grande exits the 

Espanola Basin into the Albuquerque Basin through a bedrock constriction on the southwest. On 

the west the Espanola Basin is bounded by the Pajarito Fault Zone, downthrown mainly to the 

east. The Espafiola Basin fill is semiconsolidated and comprises mainly the Tesuque, Puye, and 

Ancha Formations of the Santa Fe Group of Tertiary age, along with Quaternary and Tertiary 

volcanics, mainly on the west side.
107 COLORADO

AREA SHOWN\ 3 

IN FICURE

O

r///pf$mni \/^Jms^smim

10 20 30 40 50 MI LES

BASINS OF RIO GRANDE DEPRESSION 

LARAMIDE BASINS

PRINCIPAL OUTCROPS OF PRECAMBRIAN ROCKS 

APPROXIMATE AREA OF CERRILLOS INTRUSIVES

APPROXIMATE BOUNDARY OF TECTONIC ELEMENTS 

WHERE NOT DELINEATED BY ABOVE SYMBOLS

10 20 30 40 50 KILOMETERS

EXPLANATION

 x NORMAL FAULT Bar antf ball on downthrown side

REVERSE FAULT Shows horizontal displacement. 

Block on upthrown side

THRUST FAULT Teeth on upthrown side 

SYNCLINE Shows direction of plunge 

ANTICLINE Shows direction of plunge 

MONOCLINE OR ANTICLINAL BEND

Figure k. --Major tectonic features of north-central New Mexico (modified

from Baltz, 19?8, p. 121).

7
EXPLANATION

QUATERNARY AND TERTIARY VOLCANICS 

TERTIARY (PLIOCENE) ANCHA FORMATION 

TERTIARY (PLIOCENE) PUYE FORMATION 

TERTIARY (MIOCENE) TESUQUE FORMATION 

OTHER TERTIARY ROCKS 

PENNSYLVANIAN LIMESTONE 

PRECAMBRIAN ROCK

1 FAULT--Dashed where uncertain, dotted 

where buried, ball on downthrown side

* VOLCANIC CONE OR VENT

NOTE: Quaternary alluvial deposits not shown

Figure 5. General geology of the study area, north-central New Mexico 

(modified from Baltz, 1978; and Kelley, 1978).

EXPLANATION

.6000-_ WATER-LEVEL CONTOUR-Shows 

altitude of water level. 

Interval 100 feet. Datum 

is sea level

 M APPROXIMATE DIRECTION OF 

GROUND-WATER FLOW

INDEX TO CONTOUR MAPPING

Contours modified from:

1. Borton(1968)

2. Mourant(1980,fig.3)

3. Purtymunand Adams (1980, p. 13)

4. Purtymun and Johansen (1974, p. 348)

5. Spiegel and Baldwin (1963, pi. 6)

6. Trauger (1967, fig. 1)

Figure 6.-Predevelopment potentiometric surface in the upper part of the Tesuque aquifer

system, north-central New Mexico (modified from McAda and Wasiolek, 1988, fig. 6)

10
106°15' 106°00'

T. 

20 

N.

T. 

19

N.

T. 

18 

N.

T. 

17

N.

T. 

16 

N.

T. 

15

N.

R. 6 E. R. 7 E. R. 8 E. R. 9 E. R. 10 E.

01234 5 MILES 

ill I r~i i i i ill

012345 KILOMETERS

11
The Tesuque Formation is the main aquifer in the eastern and central parts of the study area 

and was deposited mainly as coalescing alluvial fans derived from the north and east. Tesuque 

beds generally dip westward 4 to 10 degrees where they are exposed. Steeper dips as great as 25 

degrees exist toward the east side of the exposure and less steep dips exist toward the west 

(Kelley, 1978). Dips are unknown on the west side of the basin where the Tesuque is overlain by 

younger rocks. Beds of the Tesuque vary in texture from clay to gravel, and are 

semiconsolidated. Aquifer tests in Public Service Company of New Mexico supply wells 

indicated hydraulic-conductivity values ranging from 0.2 to 20 feet per day (McAda and 

Wasiolek, 1988, p. 23). Hearne (1985, p. 8) estimated a range from 0.5 to 2.0 feet per day for the 

unit at depths likely to be penetrated by wells. McAda and Wasiolek (1988, p. 25) assumed that 

hydraulic conductivities generally decrease with depth.

The Puye Formation is of an intermediate age between the Tesuque and Ancha. The Puye is 

discussed in the following section on the geohydrology of the Los Alamos area.

The Ancha Formation of the Santa Fe Group (Spiegel and Baldwin, 1963, p. 45) is present in 

the southern part of the Espanola Basin. The Ancha, which overlies the Tesuque Formation, is 

similar to the Tesuque except that it has a lesser dip (2 to 4 degrees), it is entirely unconsolidated, 

and it is coarser and better sorted than the Tesuque. The Ancha is largely unsaturated but where 

it is saturated it probably is more permeable than the Tesuque (McAda and Wasiolek, 1988, 

p. 12). Ancha-filled channels eroded into the Tesuque form aquifers in the La Cienega area. 

McAda and Wasiolek (1988, p. 12) assumed that because of its course texture, the Ancha has 

greater recharge on its outcrop than the Tesuque has on its outcrop. For the purposes of this 

study, the Ancha is included as part of the Tesuque aquifer system.

Los Alamos Area

Los Alamos is located on the Pajarito Plateau (fig. 1), a topographic high that slopes gently 

eastward to the Rio Grande. The Pajarito Plateau is on the eastern slope of the Jemez Mountains, 

a volcanic pile that rests on and rises above a zone of faults at the western edge of the Rio Grande 

Depression (Griggs, 1964). The deepest part of the Espanola Basin may be beneath the Pajarito 

Plateau, where it could be as deep as 7,500 feet (Budding, 1978). Geologic units underlying the 

Pajarito Plateau (fig. 7) are mainly the Tesuque Formation, Chamita Formation, Chaquehui 

formation (informal usage), and Puye Formation of the Santa Fe Group. Although Purtymun 

(1995), following other authors (primarily Galusha and Blick, 1971), uses the name Puye 

Conglomerate and considers it to be post-Santa Fe on the basis of age and lithology, the formal 

U.S. Geological Survey name is used in this report, which is consistent with McAda and 

Wasiolek (1988). On the west side of the plateau the Tschicoma Formation interfingers with the 

Puye and the Tesuque or Chaquehui (Griggs, 1964, p. 18). At land surface over much of the area 

of the plateau, the Bandelier Tuff overlies the Tschicoma and Puye Formations.

The "main aquifer" in the Pajarito Plateau area of the Espanola Basin is composed mainly of the 

Tesuque and Chamita Formations, the Chaquehui formation (informal usage), and the lower part 

of the Puye Formation. High-yielding wells on the Pajarito Plateau have been developed where a 

thick section of Chaquehui formation has been penetrated. The altitude of the water table 

increases westward from the Rio Grande. The water table is in the Tesuque near the river but to 

the west it is in the Puye beneath the central and western parts of the plateau. Near the western 

part of the plateau, the water table probably is also in the Tschicoma, which intertongues with 

the Puye. Because the aquifer discharges to the Rio Grande, the hydraulic head at depth is above 

land surface near the Rio Grande and in the lower part of Los Alamos Canyon where wells in the 

Los Alamos well field originally flowed. Aquifers that are to some degree perched exist in places 

in the Tschicoma and in the alluvium that overlies the Bandelier near some of the streams.

12
Ttqb

G-5

OTpt

QTpl

H-19

QTt

Edg* ol ttructur*!

 nd/or 

 rational bmln

EXPLANATION 

Paianto Rateau

OTpf

Stratigraphy beneath the Pajanto Rateau

Figure 7.--Fence diagram of the Pajarito Plateau, north-central New Mexico 

(modified from Purtymun, 1995).

13
The Pajarito Plateau is underlain at depth by the Tesuque Formation of the Santa Fe Group 

(Kelley, 1978) or similar rocks that possibly extend west of the plateau. On the west side of the 

Pajarito Plateau, the boundary of the basin, for the purpose of this study, is marked by the 

Pajarito Fault Zone, consistent with Hearne (1985) and McAda and Wasiolek (1988). However, 

Kelley (1978) showed the Tesuque extending beneath the volcanic rocks west of the Pajarito Fault 

Zone. Near the southern end of the Pajarito Plateau, St. Peter's Dome (fig. 5), an uplifted block of 

older rocks, marks the southwestern boundary of the Espanola Basin, and occurrence of the 

Tesuque Formation beyond that point is not of concern to this study. The dip of the Tesuque, 

which is predominantly westward elsewhere in the basin, is generally unknown beneath the 

Pajarito Plateau because the Tesuque is mostly not exposed.

Aquifer characteristics of the Tesuque Formation of the Santa Fe Group have been 

estimated at wells completed exclusively in the Tesuque in the Los Alamos well field. Estimated 

horizontal hydraulic-conductivity values (Purtymun, 1984, app. A), listed in table 1, were 

derived by dividing the transmissivity by the open interval of the well. These wells penetrate an 

average saturated thickness of about 1,300 feet, and the estimated average horizontal hydraulic 

conductivity is 0.7 foot per day. Well Otowi-1 (well O-l in table 1), also completed in the Tesuque, 

has an estimated horizontal hydraulic conductivity of 0.8 foot per day. Vertical hydraulicconductivity values were not estimated; however, the ratio of vertical to horizontal hydraulic 

conductivity for the Tesuque has been estimated to be between 0.04 and 0.001 (McAda and 

Wasiolek, 1988, p. 27). Specific storage (artesian, elastic conditions) and specific yield (water-table 

conditions) have not been estimated for the Los Alamos well field. A storage coefficient of 0.088 

was estimated from pumping test data at well O-l on the basis of a 1-foot well radius, and was 

considered to be "characteristic of specific yield" (Purtymun and others, 1993). This storage 

coefficient, when divided by the length of the screened interval of the well, results in a value of 

6 x 10"5 per foot, more than 10 times the expected value of specific storage for artesian conditions, 

which might be about 1 x 10"6 per foot (Lohman, 1972). The specific yield for semiconsolidated 

sediments such as the Tesuque might range from about 0.1 to 0.3 (Johnson, 1967, p. 1). McAda 

and Wasiolek (1988) used a specific yield of 0.15 and specific storage of 1 x 10"6 per foot for the 

Tesuque.

Table 1.-Estimated horizontal hydraulic conductivity in Los Alamos National

Laboratory production and selected test wells

[Well locations shown in figures 2,7, and 17]

Well name

LA-IB

LA-2

LA-3

LA-4

LA-5

LA-6

G-l

G-1A

G-2

G-3

G-4

G-5

Estimated

hydraulic 

conductivity

(feet/day)

1.2

0.5

0.4

0.6

0.4

1.2

0.9

1.2

1.2

0.7

1.5

1.2

Well name

G-6

PM-1

PM-2

PM-3

PM-4

PM-5

DT-5A

DT-9

DT-10

0-1

0-4

Estimated

hydraulic 

conductivity

(feet/day)

0.9

4.1

3.7

24.

3.2

0.7

2.3

16.

15.

0.8

5.7

14
The Chamita Formation of the Santa Fe Group was first defined by Galusha and Blick 

(1971). However, Kelley (1978) mapped the Chamita with the underlying Ojo Caliente Sandstone 

Member of the Tesuque Formation, which Galusha and Blick (1971) considered to be the 

uppermost member of the Tesuque. Like the Tesuque, the Chamita consists of siltstones, sandy 

siltstones, and sandstones and was derived from the highlands to the north. The Chamita is 

thickest in the northern part of the Espanola Basin but thins southward to less than 30 feet near 

the Otowi Bridge (fig. 1). The Chamita is absent in the Guaje well field and was eroded away or 

never deposited in the Los Alamos area (Purtymun, 1995). Because the lithologic and hydrologic 

characteristics of the Chamita are similar to those of the Tesuque and because the Chamita is thin 

or absent (fig. 7), the Chamita Formation in the Pajarito Plateau is considered in this report to be 

hydrologically part of the Tesuque, consistent with McAda and Wasiolek (1988). Aquifer 

characteristics of the Chamita are unknown but assumed to be the same as those of the Tesuque.

Rocks here called the Chaquehui formation of the Santa Fe Group (informal usage of 

Purtymun, 1995) were first noted but not named by Griggs (1964) during the construction of the 

Guaje well field. This thick section of rocks occupies the upper part of what he called the 

undifferentiated unit of the Santa Fe Group. The undifferentiated unit is mostly Tesuque 

Formation; however, unlike the Tesuque, the upper part of the undifferentiated unit is made up 

of volcanic debris from the west and granitic debris from the north and east. Purtymun (1995) 

separated this section of course-grained volcanic and granitic sediments from the Tesuque and 

Chamita Formations of the Santa Fe Group on the basis of geologic logs, geophysical logs, and 

well cuttings, calling it the Chaquehui formation. Interbedded in the Chaquehui are basalts 

thought to have originated east of the Rio Grande (W.D. Purtymun, oral commun., September 

1994). The interbedded basalts, about 8 million years old, are almost as old as the Chamita 

(Purtymun, 1995).

The Chaquehui formation occupies much of an ancient "channel" eroded or faulted about 

1,000 feet into the Tesuque Formation. From well logs, the channel appears to be about 3 to 

4 miles wide and trends north-northeast through the Guaje and Pajarito Mesa well fields. This 

channel seems to coincide with a slightly smaller graben inferred from gravity work by Budding 

(1978) to be about 6 miles long and 3 miles wide. Although the western extent of the Chaquehui 

is not precisely known, it was not found at test well TW-4 (fig. 7). On the east side, the Chaquehui 

ends abruptly between production wells PM-1 and O-l. The northern and southern extremities 

of the channel are unknown. Found mainly in the subsurface, a thin section of the Chaquehui 

crops out in White Rock Canyon north of the mouth of Chaquehui Canyon, which is just north of 

Canon de los Frijoles (fig. 1). The Chaquehui is partially saturated in the Guaje well field and 

fully saturated in the Pajarito Mesa well field where W.D. Purtymun (oral commun., 1993) 

credited the Chaquehui and the Totavi Lentil of the Puye Formation with the relatively larger 

productivity of that field.

Horizontal hydraulic conductivity of the Chaquehui formation has been estimated in the 

northern part of the Pajarito Mesa well field and in the western part of the Otowi well field. Wells 

PM-1, PM-3, and O-4 are completed mainly in the Chaquehui formation and to a lesser degree in 

the Tesuque Formation. Estimated horizontal hydraulic conductivity (Purtymun, 1984, app. A) 

averaged 11 feet per day. The average saturated thickness was about 1,700 feet. In the Guaje well 

field, estimated horizontal hydraulic conductivity (table 1) averaged about 1 foot per day in 

wells penetrating an average of 1,400 feet of saturated thickness, of which about half is 

Chaquehui and about half is Tesuque. These estimated hydraulic-conductivity values are for the 

combined section of Chaquehui, Tesuque, and interbedded basalts. The ability of the basalts to

15
transmit water is thought to result from fracturing that occurred at the time of emplacement as 

interflow breccia zones. These rocks yield water to wells and their hydraulic conductivity is 

thought (W.D. Purtymun, oral commun., January 6, 1994) to be generally similar to that of the 

Chaquehui formation. Vertical hydraulic conductivity has not been estimated for the Chaquehui 

formation. A storage coefficient of 1.93 x 10"3 was estimated from pumping test data at well O-4 

on the basis of a 1-foot well radius, and was considered to be representative of a leaky confined 

aquifer and "consistent with hydrogeological observations from adjacent production wells" 

(Stoker and others, 1992). This storage coefficient, when divided by the length of the screened 

interval of the well, results in a value of 1.3 x 10"6 per foot, comparable to the expected value of 1 

x 10"6 per foot for artesian specific storage. A specific yield has not been estimated for the 

Chaquehui but may be similar to other semiconsolidated sediments.

The Puye Formation includes the Totavi Lentil and a fanglomerate member, as described by 

Griggs (1964, p. 28-37). The Totavi Lentil is at the base of the Puye and overlies the Tesuque 

Formation where the Totavi crops out on the east side of the Pajarito Plateau (Griggs, 1964, p. 29). 

Within the plateau, the Totavi overlies the Chaquehui formation. The age of the Puye Formation 

may be less than half that of the Chaquehui. The Totavi is 50 to 60 feet thick and is composed 

mainly of reworked Precambrian gravel and sand (Kelley, 1978). It is unsaturated in the Guaje 

well field. The Totavi is also unsaturated where it crops out in Los Alamos Canyon but has 

springs associated with it farther south in White Rock Canyon. The Totavi is saturated 

throughout much of the Pajarito Plateau and contributes water to wells in the Pajarito Mesa and 

Otowi well fields.

The fanglomerate member of the Puye Formation overlies the Totavi Lentil. The thickness 

of the fanglomerate ranges from the pinch-out near the east side of the Pajarito Plateau to more 

than 600 feet at well TW-2 (fig. 7). An erosional surface at the top of the fanglomerate prevents 

determination of its original thickness. The fanglomerate is composed of debris washed 

eastward from rocks of the Tschicoma Formation and includes mainly sand and silt with gravel 

and boulders. The coarser material is to the west and the finer material is to the east. Bedding 

planes dip 1 to 2 degrees eastward, with greater dip angles locally. The fanglomerate member is 

unsaturated where present in the western end of the Los Alamos well field and in the Guaje well 

field. It is partially saturated in the Pajarito Mesa well field.

Basaltic rocks of Chino Mesa (fig. 7) are interbedded throughout the fanglomerate member 

of the Puye Formation (fig. 7). The basaltic rocks of Chino Mesa originated from volcanic centers 

on Chino Mesa east of the Rio Grande. Griggs (1964, p. 37) described five units, each consisting 

of more than one basalt flow. Units 1 and 2 also contain basaltic tuffs. The basaltic rocks of Chino 

Mesa are not known to be cavernous and, as with the older basalts in the Chaquehui formation, 

their ability to transmit water is considered to result from interflow breccia zones.

Horizontal hydraulic-conductivity values for the individual members of the Puye 

Formation have not been determined; however, values for a combined section of the Chaquehui 

formation, the Totavi Lentil of the Puye Formation, and lower part of the fanglomerate member 

of the Puye have been estimated. The estimated horizontal hydraulic conductivity (Purtymun, 

1984, app. A) averages about 2.5 feet per day at wells PM-2, PM-4, and PM-5 in the Pajarito Mesa 

well field (table 1). The average saturated thickness at these three wells is about 1,700 feet. This 

estimated horizontal hydraulic conductivity is an "average" for the members of the Puye 

Formation and Chaquehui formation and the interbedded basaltic rocks of Chino Mesa. At a 

group of test wells (DT-5A, DT-9, and DT-10), located southwest of the Pajarito Mesa well field, 

estimated hydraulic conductivity averaged 11 feet per day. This group of test wells penetrates an

16
average of 490 feet of saturated thickness, including parts of the fanglomerate member of the 

Puye, the Totovi Lentil, part of the Chaquehui, and some of the interbedded basaltic rocks of 

Chino Mesa. Vertical hydraulic conductivity for the Puye has not been determined. Specific yield 

and specific storage have not been determined for the Puye but they probably have magnitudes 

similar to those for the Tesuque Formation and Chaquehui formation.

The Tschicoma Formation of Pliocene age and the Bandelier Tuff of Pleistocene age are 

major volcanic units in the Pajarito Plateau. The Tschicoma Formation interfingers with and is 

approximately the same age as the Puye Formation (Kelley, 1978). The Tschicoma forms the 

mountains west of Los Alamos and is present beneath the surface of the western edge of the 

Pajarito Plateau. It is composed of latite, quartz-latite flows, and pyroclastic rocks, and is not 

known to be cavernous. The permeability of the Tschicoma, less permeable than the Puye, is 

thought to result from fractures formed at the time of deposition (W.D. Purtymun, oral commun., 

1993-94).

At one test well (TW-4) located northwest of the Pajarito Mesa well field, the hydraulic 

conductivity of the Tschicoma Formation was estimated to be about 2 feet per day (Rirtymun, 

1984, p. 16); however, this well was completed in a brecciated zone and may not represent the 

entire Tschicoma. W.D. Purtymun (oral commun., January 6, 1994) reported that of three wells 

attempted in the Tschicoma about 4 miles west of Los Alamos, only one produced a limited 

supply of water from a perched zone; the others were "dry." Specific yield and specific storage of 

the Tschicoma have not been determined.

The Bandelier Tuff overlies the Tschicoma Formation along the flanks of the mountains and 

overlies the Puye Formation and basaltic rocks in the remainder of the Pajarito Plateau. The 

Bandelier is a series of ash flows and ash falls of rhyolitic tuff and caps the Pajarito Plateau. It 

varies in thickness from about 1,000 feet on the west side of the Pajarito Plateau to about 200 feet 

on the east side. The Bandelier, along with the upper part of the underlying Puye and possibly 

the upper parts of the eastern edge of the underlying Tschicoma, generally occupies the 

unsaturated zone at Los Alamos. Because the water-yielding characteristics of the Bandelier 

relate mainly to recharge on the Pajarito Plateau, these characteristics are discussed in the 

following section on recharge.

The Pajarito Fault Zone lies near the western edge of the Pajarito Plateau. South of Los 

Alamos the Bandelier Tuff on the east side of the fault is downthrown about 300 feet relative to 

the tuff on the west side of the fault. Faults along the Pajarito Fault Zone are generally 

downthrown on the east (Kelley, 1978); however between Los Alamos and Guaje Canyons, 

several faults are downthrown on the west. Although Hearne (1985), Me Ada and Wasiolek 

(1988), and Finch and Fleming (1992) considered the Pajarito Fault Zone to be the western 

boundary of the Espanola Basin, the possible westward extent of the Tesuque Formation and its 

hydraulic continuity westward beyond the Pajarito Fault Zone are unknown.

17
Ground-Water Flow, Recharge, and Discharge

Me Ada and Wasiolek (1988) constructed a predevelopment potentiometric-surface map 

(fig. 6) for the Tesuque aquifer system that was based on several maps published by other 

authors (Spiegel and Baldwin, 1963, pi. 6; Trauger, 1967, fig. 1; Borton, 1968; Purtymun and 

Johansen, 1974, p. 348; Mourant, 1980, fig. 3; Purtymun and Adams, 1980, p. 13). Any 

predevelopment map needs to be used with some caution. Generally, by the time enough wells 

have been drilled in a semiarid region to construct a potentiometric-surface map, the aquifer has 

been partially developed, and measured water levels, even at newly constructed wells, may not 

truly represent a predevelopment surface. The maps used by McAda and Wasiolek are a 

compilation of the work of various authors at various times and therefore may only be assumed 

to represent predevelopment conditions. If the aquifer is assumed to be horizontally isotropic, 

the direction of ground-water flow is perpendicular to the potentiometric contours. Water 

generally flows from the mountains on the west and east sides of the basin toward the Rio 

Grande, which traverses the basin from northeast to southwest (McAda and Wasiolek, 1988, 

p. 12-13). Because the Rio Grande is the main receiver of discharge, the hydraulic gradient is 

upward near the Rio Grande and wells near the Rio Grande may flow.

The Sangre de Cristo Mountains provide recharge to the Tesuque aquifer system as 

subsurface flow along the mountain front and as percolation from stream channels where they 

discharge from the mountain front onto the basin. The quantity of water entering the aquifer as 

subsurface flow along the mountain front was estimated by McAda and Wasiolek (1988, p. 29), as 

the remainder of precipitation minus evapotranspiration and runoff, to be between 0.7 and 

3.0 cubic feet per second per mile of mountain front. The percolation from stream channels where 

they discharge onto the basin fill along the Sangre de Cristo Mountains was estimated by McAda 

and Wasiolek (1988, p. 29) from streamflow estimates of other authors (Spiegel and Baldwin, 

1963, p. 173-175, 250; Reiland, 1975; and Reiland and Koopman, 1975, p. 9-27) to be about 

18 cubic feet per second. No estimates were made by McAda and Wasiolek (1988) for streams 

discharging from mountains along the west side of the basin.

The Jemez Mountains probably provide some recharge on the west side of the basin as 

indicated by the potentiometric surface, which slopes generally from the Jemez Mountains to the 

Rio Grande; however, the quantity attributable to each component and the total ground-water 

flow through the area are unknown. Components might include subsurface flow from the 

mountains across the Pajarito Fault Zone into the west side of the Pajarito Plateau, percolation 

from stream channels that cross the plateau, and areal recharge from precipitation on the plateau.

The age of ground water west of the Rio Grande generally increases from west to east, 

consistent with a general west-to-east flow direction shown in figure 6. R.R. Spangler (Rust 

Geotec, written commun., 1993) found that water from the west side of the Pajarito Mesa well 

field was between 1,000 and 5,000 years old, whereas water from the east end of Los Alamos well 

field was between 27,000 and 39,000 years old. A.K. Stoker (Los Alamos National Laboratory, 

oral commun., 1993) suggested, on the basis of gradient and hydraulic properties, that the rate of 

ground-water movement in the upper part of the main aquifer could be a few tens to a few 

hundred feet per year. By assuming a distance of 5 to 10 miles, the age of water in the upper part 

of the aquifer could be less than a thousand years. This wide range of ages is consistent with the 

existence of relatively new water near the top of the saturated zone and older water deeper in the 

system. Also, the deeper water in the east end of the Los Alamos well field could conceivably 

have originated in the Sangre de Cristo Mountains on the east, a possibility that is suggested also 

by oxygen-18 and deuterium analyses.

18
Fraser Goff (Los Alamos National Laboratory, written commun., 1991) used concentrations 

of oxygen-18 and deuterium to postulate that water from the east end of the Los Alamos well 

field (well LA-IB) might have recharged at altitudes higher than the Jemez Mountains, 

suggesting the Sangre de Cristo Mountains. He also suggested that waters withdrawn from most 

of the production wells of the Pajarito Mesa and Guaje fields originated at altitudes lower than 

the Valle Grande (the floor of the Jemez Caldera), excluding most of the area of the mountains 

west of the Pajarito Fault Zone, which generally are higher than the Valle Grande. This implies 

that recharge could be limited to the Pajarito Plateau and a narrow belt of the mountain slope 

west of the Pajarito Plateau.

Recharge from precipitation is thought to be minor over much of the area of the Bandelier 

Tuff, which covers most of the Pajarito Plateau (Abrahams and others, 1961). Although porosity 

ranges from 18 to 52 percent and "field capacity" is around 20 to 40 percent, the Bandelier 

generally is unsaturated, having a water content of less than 4 percent by volume. Little or no 

water moves in the Bandelier where the moisture content is less than about 12 percent, according 

to Purtymun and others (1989, p. 5). The generally very low moisture content of the Bandelier 

probably indicates that evapotranspiration generally equals or exceeds precipitation and that the 

moisture storage capacity within the root zone is large enough to keep precipitation from 

percolating beyond the root zone. Purtymun and others (1989, p. 3-5) reported that the hydraulic 

conductivity of the Bandelier at saturation ranges from approximately 0.01 to 0.1 foot per day, 

values comparable to those of silt (Freeze and Cherry, 1979, p. 29); however, a considerable 

volume of water would be required to increase saturation enough for hydraulic conductivity to 

approach that of saturated conditions. The range of hydraulic conductivity of the Bandelier at 

saturation may be much greater than reported because of varying degrees of welding.

Though natural recharge from precipitation may be relatively insignificant on an annual 

basis, the larger hydraulic conductivity for the Bandelier Tuff at saturation might allow recharge 

in places where saturation occurs. Given a sufficiently constant, long-term source of water and 

no confining bed less permeable than the Bandelier, a saturated zone extending through the 

Bandelier and into the water table in the Puye Formation is quite possible. Flow would then be 

controlled largely by the hydraulic conductivity under saturated conditions along the flow path, 

which would allow more recharge of the main aquifer than would occur under unsaturated 

conditions. This saturated condition could have occurred in canyons before water was diverted 

for Los Alamos public supply, probably where canyons enter onto the western side of the 

Pajarito Plateau, or where there is a "perched aquifer" of long duration in the alluvium. The 

quantity of main aquifer recharge by this route has not been estimated. The age (1,000 to 

40,000 years) of water in production wells, which tend to be located in the lower reaches of 

canyons, seems to indicate little or no recharge in these lower reaches.

Another possible route of recharge is along the Pajarito Fault Zone. The quantity of 

recharge by this route has not been estimated.

Recharge over the area of the Santa Fe Group is unknown but also probably small. 

Although Lee Wilson and Associates (1978, p. 1.62) considered 0.28 inch per year to be a low 

estimate of recharge to the aquifer from the area covered by the Santa Fe Group, Anderholm 

(1994) concluded on the basis of chloride profiles in the soil that there is no recharge except in 

sandy arroyos. McAda and Wasiolek (1988) theorized that surfaces on the more course grained 

geologic units such as the Ancha Formation would have relatively more recharge than the finer 

grained units such as the Tesuque Formation and the volcanic units in the basin.

19
Some streams flowing across the Santa Fe Group lose water to the aquifer in their upper 

reaches and gain water from the aquifer in their lower reaches. Me Ada and Wasiolek (1988, p. 43) 

showed that ground-water recharge from the Pojoaque River and tributaries within the modeled 

area was about 1.4 cubic feet per second greater than ground-water discharge. They determined 

this on the basis of the discharge of 14.8 cubic feet per second at the mouth (Reiland, 1975, p. 19), 

estimated inflow of 17.7 cubic feet per second from outside the modeled area (Reiland, 1975, p. 11 

and 17; and fig. 1), runoff of 2.9 cubic feet per second from areas within the modeled area 

(estimated on the basis of Reiland, 1975, p. 19), and evapotranspiration of 4.4 cubic feet per 

second within the modeled area (Hearne, 1985, p. 13).

Although the amount of ground-water discharge along the entire length of the Rio Grande 

within the modeled area (between Espanola and a point about 4 miles upstream from Cochiti 

Pueblo) is unknown, streamflow gain has been estimated for the reach between streamflow 

gages at Otowi Bridge (station 08313000) and near Cochiti Pueblo (station 08314500) (fig. 2). 

Estimates by Spiegel and Baldwin (1963, p. 200-201) of 25 cubic feet per second over a 26-mile 

reach (0.96 cubic foot per second per mile) between the streamflow gages at Otowi Bridge and 

near Cochiti Pueblo and by Griggs (1964, p. 95) of 500 to 600 gallons per minute per mile 

(1.1 to 1.3 cubic feet per second per mile) in a 21-mile reach downstream from Otowi Bridge are 

consistent except for a different estimated river mileage. Gains in discharge between the Otowi 

Bridge streamflow gage and Canon de los Frijoles were reported to range from 6 to 29 cubic feet 

per second and to average 15 cubic feet per second by W.D. Purtymun (U.S. Geological Survey, 

written commun., 1966) and by Purtymun and Adams (1980, p. 5). Ground-water discharge to 

the Rio Grande is probably the sum of gain in streamflow and loss to evapotranspiration. Almost 

the entire Otowi Bridge to Cochiti Pueblo reach is in White Rock Canyon where McAda and 

Wasiolek (1988, p. 44) estimated that the loss to evapotranspiration " * * * probably is not more 

than about 3 cubic feet per second/' Thus, ground-water discharge to the reach from Otowi 

Bridge to Cochiti Pueblo could be in the range of about 10 to 30 cubic feet per second.

Ground-Water Withdrawals and Changes in Recharge

Most ground-water withdrawals within the modeled area are from well fields that supply 

Los Alamos (Los Alamos, Guaje, Pajarito Mesa, and Otowi well fields) and Santa Fe (Santa Fe 

and Buckman well fields). Before 1947, Los Alamos was supplied by surface water from five 

canyons: Guaje, Los Alamos, Pajarito, Canon de Valle, and Water Canyon. The larger 

streamflows continue to support some irrigation needs. Los Alamos well field began producing 

in about 1947 (fig. 8A) and went out of service for municipal supply during 1992; it provided a 

temporary supply for road construction during 1993. The Guaje well field began producing in 

1950 and the Pajarito Mesa field in 1965. Wells in the new Otowi well field came on line during 

1993. The Santa Fe well field began producing in about 1950 (fig. 8B) and the Buckman well field 

in about 1972. Before the 1950's, Santa Fe was supplied by surface water from the Santa Fe River, 

which continues to supply a significant part of Santa Fe's needs, depending on the weather. The 

variable availability of surface water in Santa Fe probably explains the variability in groundwater withdrawals there. Also shown in figure 8B are estimated withdrawals for individual 

wells that are not included in the well fields, but for which records are available in the New 

Mexico State Engineer Office. Comparison of graphs shown in figure 8 indicates that estimated 

withdrawals from wells outside major well fields constitute about 10 percent of total withdrawal 

from all wells.

20
3] CQ'

c 

^

CD 

CO

6^

_. o

3 C

9: 3

< Q.

& *

03 CU

§

CD

rn

GROUND-WATER WITHDRAWAL, IN CUBIC FEET PER SECOND

GROUND-WATER WITHDRAWAL, IN CU

CD

O 13 

CD Q.

ZJ

CD Q) 

5 CD
Annual withdrawals from individual wells were estimated if records were not available. 

Thus, the quantities shown in figure 8 are based mostly on reported values but include some 

estimated quantities. McAda and Wasiolek (1988, p. 45) determined ground-water withdrawals 

for 1947-82 and identified the source of reported values and the assumption used to determine 

estimated values.

For 1983-92, records of ground-water withdrawals from wells in the well fields were 

obtained from the State Engineer Office and from Los Alamos National Laboratory. Pumping 

records for individual wells in the Buckman well field were not available for 1987 and 1988. Total 

pumpage for 1987 was prorated between wells B-l and B-2 in the proportions indicated by 

records for 1986. Similarly, total pumpage for 1988 was prorated among wells B-l through B-6 in 

the proportions indicated by records for 1989. Annual withdrawals from wells not included in 

the major well fields were estimated to have increased from 1983 to 1992 at the same rate as the 

population growth of Santa Fe County between 1980 and 1990.

As understanding of the geologic framework of the main aquifer at Los Alamos improved, 

ground-water supplies were developed first near the Rio Grande, then westward and 

southward. The first water-supply wells were drilled in Los Alamos and Guaje Canyons at the 

eastern edge of the Pajarito Plateau. These wells were completed mainly in the Tesuque 

Formation and produced less than 500 gallons of water per minute. Los Alamos well field 

produced water entirely from the Tesuque Formation, and the Guaje well field produced water 

from the lower part of the Chaquehui formation (informal usage) and from the Tesuque. As more 

water was needed, additional wells were drilled to the west and south, mainly in canyons that 

cut through the plateau. The Pajarito Mesa wells were completed mainly in the lower 

fanglomerate and Totavi Lentil Member of the Puye Formation, in the Chaquehui, and in the 

upper Tesuque. They produced about 1,500 gallons of water per minute (Purtymun and Cooper, 

1969). The most recent wells were drilled in the Otowi well field, located among the other three 

fields. Well Otowi 1 (O-l) is completed in the Totavi and in the Tesuque because the Chaquehui is 

absent. The other Otowi well (O-4) is completed in the same formation as the Pajarito Mesa 

wells.

Older wells in the Los Alamos and Guaje well fields are being taken out of service. The 

entire Los Alamos field was out of service as of 1993, and production has been shifted to the 

Pajarito Mesa and Otowi fields. The first six wells in the Guaje field are scheduled for 

replacement by four wells interspersed among and to the west of the old wells so that the center 

of the well field will move about 0.5 mile westward and slightly northward.

Municipal water developments have been accompanied by changes in recharge from 

predevelopment conditions. Diversion of the Santa Fe River for public supply undoubtedly 

changed the location and quantity of ground-water recharge along that drainage. Similarly, 

diversion of the small streams in the canyons of the Pajarito Plateau must have resulted in less 

streamflow in places and introduced perennial flows in places that formerly were ephemeral, 

probably resulting in changes in the location and quantity of recharge in those areas. Subsequent 

ground-water withdrawals likely have resulted in additional treatment-plant effluent and 

downstream recharge.

22
For the Santa Fe River, McAda and Wasiolek (1988, p. 46) considered that predevelopment 

recharge near the mountain front probably was reduced by the average quantity of surface water 

diverted for municipal use. The quantity of water diverted was reported by the Sangre de Cristo 

Water Company. McAda and Wasiolek (1988) estimated ground-water recharge from the Santa 

Fe River, in cubic feet per second, to have been:

Predevelopment...7.5 1963-67 ...............2.0

1947-52...................4.5 1968-72...............2.3

1953-57...................5.0 1973-77...............2.6

1958-62...................2.5 1978-82...............2.2

McAda and Wasiolek (1988, p. 46-47) described the estimated location and methods of 

disposal of Santa Fe sewage treatment-plant effluent, which eventually recharges the aquifer. For 

a time, some was used for irrigation, but recently it has been discharged to the Santa Fe River, 

where it infiltrates into the aquifer within 1 to 2 miles of the discharge point. McAda and 

Wasiolek (1988, p. 47) estimated ground-water recharge from sewage treatment-plant effluent, in 

cubic feet per second, to have been:

1947-52.................. 2.9 1963-67.................. 3.7

1953-57.................. 3.2 1968-72.................. 4.1

1958-62.................. 3.4 1973-77.................. 4.4

1978-82.................. 4.7

For the purpose of this study, the quantity of sewage plant effluent for 1983-92 was 

assumed to have been 50 percent (Sorensen, 1977) of the sum of Santa Fe surface-water 

diversions and ground-water withdrawals for public supply. Surface-water diversion data for 

1983-91 were obtained from the New Mexico State Engineer Office. In the absence of 1992 

surface-water diversion data, the quantity of recharge was assumed to have been the same as in 

1991. Estimated annual ground-water recharge from sewage plant effluent for 1983-92 was 

5.4, 5.5, 5.1, 5.7, 6.4, 7.2, 7.6, 7.1, 6.9, and 6.9 cubic feet per second, respectively.

For the Pajarito Plateau, the destination of sewage treatment-plant effluent has not been 

determined because of the complexity of the flow systems. The Pajarito Plateau has two major 

municipal sewage treatment plants, one located in Pueblo Canyon (north of and paralleling Los 

Alamos Canyon) serving the Los Alamos town site and the other in the lower end of Canada del 

Buey serving White Rock. Recharge of the main aquifer from the White Rock sewage-treatment 

plant is unlikely because it is located near the Rio Grande. The effluent can be observed in a thin, 

high waterfall tumbling off a massive basaltic rock into White Rock Canyon.

The effluent from the Los Alamos town site sewage treatment plant is discharged to the 

lower reach of Pueblo Canyon, which is otherwise ephemeral. Effluent-supported flow joins 

natural flows in Los Alamos Canyon that, during 1992, generally extended approximately to the 

confluence with Bayo or Guaje Canyons (Los Alamos National Laboratory, 1993, p. 2-25). Some 

of the effluent temporarily resides in the perched alluvial aquifer, then is consumed by 

evapotranspiration or flows to the Rio Grande. The main aquifer in the lower 2 miles of Los 

Alamos Canyon could have been recharged when water levels in the Los Alamos well field were

23
drawn down. However, under predevelopment conditions, and after closure of the well field, 

recharge is not likely because the potentiometric surface of the main aquifer is higher than the 

canyon bottom. Recharge of the main aquifer is possible immediately downstream from the 

treatment-plant outfall where there is a downward hydraulic gradient; given enough time, 

recharge probably will occur at some unknown rate. The time and rate of recharge are probably 

determined by the water-yielding properties and previous moisture content of the intervening 

rock. Although recharge could eventually occur, the combination of low hydraulic conductivity 

and high porosity of the Bandelier Tuff probably have retarded recharge to some unknown 

extent.

SIMULATION OF GROUND-WATER FLOW

Although the ground-water flow model was altered from that of McAda and Wasiolek 

(1988), the same flow equation and computer program were used (the U.S. Geological Survey 

modular model MODFLOW, by McDonald and Harbaugh, 1988). The flow equation is:

5/5x (Kx 8h/5x) + 5/6y (Ky 6h/5y) + 5/5z (Kz 5h/5z) - W = Ss(5h/5t) (1) 

where Kx,KyK2 are the hydraulic-conductivity values in the x, y, and z directions, respectively;

h is the hydraulic head;

W is the volume of water recharged or withdrawn per unit volume per unit time;

Ss is the specific storage of the aquifer material; and

t is time.

For steady-state conditions, this flow equation is solved with specific storage set to zero. 

The flow equation was solved with the Strongly Implicit Procedure (SIP), the same as that used 

by McAda and Wasiolek (1988).

The model was adjusted to simulate hydraulic heads, especially those in or near well fields 

under transient conditions, by modifying the specified values of hydraulic conductivity, 

recharge, and storage. Each time a modification of hydraulic conductivity or recharge was made, 

a steady-state condition was calculated to derive preconditional hydraulic-head values for 

subsequent transient simulations. In the following discussions, the steady-state condition is 

described with the transient condition; the distinction is made as needed.

Description of the Model and Modifications to the McAda-Wasiolek Model

The model required specification of a finite-difference three-dimensional grid, hydraulic 

conductivity and storage characteristics, time periods, and boundary conditions. Some values of 

the McAda-Wasiolek model were changed during development of the new model. Aquifer 

characteristics reported in this section are slightly different from those of the McAda-Wasiolek 

model, but in most cases, the model is the same or similar.

Model Grid

The three-dimensional rectangular grid was modified in the vertical dimension from that of 

McAda and Wasiolek (1988), but the grid in the horizontal plane (fig. 9) remained the same. In 

the vertical dimension (fig. 10), from the top downward, the top layer of McAda and Wasiolek 

(1988) was split into three layers 200, 275, and 325 feet thick; the second layer was split into two

24
layers 475 and 725 feet thick; and the bottom two layers combined were split into three layers 

1,000,1,200, and 1,400 feet thick The additional layering was needed to improve the simulation 

of vertical flow, especially to simulate more correctly the location of water-table storage near the 

top of the flow system and to simulate more realistically the resistance to vertical low from the 

water table to the open intervals of the deep municipal supply wells.

These specific thicknesses were selected for practical considerations. Although thinner 

layers might have given better vertical resolution, a water-table layer thinner than 200 feet would 

have been troublesome because of cells "going dry" as explained in a following discussion. The 

conversion from the McAda-Wasiolek model was facilitated by keeping individual wells, those 

not in well fields, in the top layer as in the McAda-Wasiolek model. Construction details of many 

individual wells are unknown. Those wells for which characteristics are known, however, mostly 

penetrate no deeper than 200 feet below the water table.

In the horizontal plane, the extent of layers is shown in figure 9 as "active" and, by 

inference, inactive parts of the model grid. The flow equation is solved only for the active parts of 

the grid, as explained by McDonald and Harbaugh (1988, chap. 3, p. 15). The extent of layers 

1-3 was the same as that of the McAda-Wasiolek (1988) layer 1, and the extent of layers 4-5 was 

the same as that of the McAda-Wasiolek layer 2. The extent of layer 6 was the same as that of the 

McAda-Wasiolek layer 3, and the extent of layer 8 was the same as that of the McAda-Wasiolek 

layer 4. Layer 7, straddling the McAda-Wasiolek layers 3 and 4, has an intermediate extent.

Figure 10 indicates that the deeper model layers might extend farther east than the basin fill 

but not as far west as the basin fill. However, Me Ada and Wasiolek (1988) constructed their 

model on the basis of the geologic interpretations of many authors, whereas the contact between 

basin fill (Tesuque Formation) and bedrock (Mesozoic-Precambrian rocks) shown in figure 10 

reflects the interpretations of only one author (Kelley, 1978). The extent of the model and the 

extent of basin fill may not coincide at depth because the extent of basin fill is not well known.

Hydraulic Conductivity, Transmissivity, and Leakance

Model input for MODFLOW requires a horizontal hydraulic conductivity for each cell in 

layer 1, transmissivity for each cell in layers 2-8, and a leakance for each cell in layers 1-7. 

Although transmissivity was used in the model for layers 2-8, the following discussion is in 

terms of hydraulic conductivity and leakance. Transmissivity was calculated as hydraulic 

conductivity multiplied by layer thickness. Leakance values were calculated from vertical 

hydraulic-conductivity values and layer thickness according to equation 51 of McDonald and 

Harbaugh (1988):

vcontifitk+1/2 =l/{[(delvfc/2)/(kzJ- ;/fc)]+[(delvfc+2 /2)/(kzf/^+2 )]} (2)

where vcont,-; ^+2/2 ^ leakance between a layer k and the underlying

layer k+1 at row i, column j (L/T); 

is thickness of model layer k (L); 

is thickness of the underlying model layer k+1 (L);

is vertical hydraulic conductivity of the upper layer at cell i,j,k (L/T); and 

j; fc+2 is vertical hydraulic conductivity of the lower layer at cell i,j,k+l (L/T).

25
COLUMN 106*00' 

20

o

cc

30

R.6E.

0 1 2 3 MILES

i___i

0123 KILOMETERS

R.7E.

EXPLANATION

CZl ALL LAYERS ACTIVE m& LAYERS 1 -3 ACTIVE 

CZ1 LAYERS 1-7 ACTIVE mB NO LAYERS ACTIVE 

EUD LAYERS 1-6 ACTIVE 

^ LAYERS 1-5 ACTIVE

Figure 9.-Horizontal model grid and extent of layers. 

26

EXTENT OF ACTIVE 

PART OF LAYER
WEST

N>

EXPLANATION

QUATERNARY BANDELIER TUFF 

TERTIARY VOLCANICS 

TERTIARY PUYE FORMATION

TERTIARY TESUQUE FORMATION 

MESOZOIC-PRECAMBRIAN ROCKS MODEL LAYER 

FAULT

EAST

2 4

I i i i

6 8 MILES

i i___i

r i I I I I I I I 

02468 KILOMETERS

Figure 10.--Diagrammatic section along model row 9 showing model layers and subsurface geology 

(geology modified from Kelley, 1978, section C-C').
Vertical hydraulic conductivity in each cell was calculated as 0.02 times horizontal 

hydraulic conductivity, a multiplier developed by model adjustment/ which is within the range 

of 0.04 to 0.001 previously cited for the Tesuque Formation.

Horizontal hydraulic-conductivity values were the same as those of McAda and Wasiolek 

(1988), with exceptions as described in following paragraphs. That is, the horizontal hydraulicconductivity values of layers 1-3 (fig. 11) were the same as those of layer 1 of McAda and 

Wasiolek, and the horizontal hydraulic-conductivity values of layers 4 and 5 (fig. 12) were the 

same as those of layer 2 of McAda and Wasiolek. The horizontal hydraulic-conductivity values of 

layers 6 and 8 (fig. 13) were the same as those of layers 3 and 4, respectively, of McAda and 

Wasiolek. Because layer 7 straddled layers 3 and 4 of McAda and Wasiolek, the horizontal 

hydraulic conductivity of layer 7, which was 1,200 feet thick, was calculated as (800I<3 + 400K4)/ 

1,200, where K3 and K4 were the hydraulic-conductivity values of layers 3 and 4, respectively, of 

McAda and Wasiolek. With one exception, the hydraulic conductivity (not shown) was 0.1 foot 

per day in layer 6,0.07 foot per day in layer 7, and 0.02 foot per day in layer 8 where these layers 

are active (fig. 9). The exception was in the area near La Cienega where, as in layers 4-5, the 

hydraulic conductivity was 0.02 foot per day in layers 6-8.

Horizontal hydraulic-conductivity values in the northwestern part of the modeled area 

(figs. 11-12) were established mainly on the basis of the comparison of long-term measured and 

model-derived hydrographs in well fields. The area west of White Rock Canyon, where McAda 

and Wasiolek (1988, fig. 10) represented the Tesuque Formation with a hydraulic conductivity of 

0.3 foot per day, was expanded to include the Buckman well field and much of the area west of 

the Rio Grande. However, at the eastern end of the Los Alamos well field, the hydraulic 

conductivity representing the Tesuque was 0.1 foot per day in layers 1-5. The hydraulic 

conductivity representing the Chaquehui formation in the Guaje well field was 0.4 foot per day. 

The hydraulic conductivity representing the Chaquehui formation and Puye Formation was 5 

feet per day in the Pajarito Mesa well field and 2 feet per day southwest of the Pajarito Mesa well 

field (fig. 11). The Chaquehui, which is largely unsaturated in the Guaje well field, is represented 

only in layers 1 and 2, whereas in the Pajarito Mesa well field the Chaquehui and Puye are 

represented in layers 1-4. The hydraulic conductivity representing the interfingering of the 

Tschicoma Formation with the Puye and Tesuque near the Pajarito Fault Zone was set to 0.3 

foot per day because the Tschicoma is generally less permeable than the Puye.

Specified hydraulic-conductivity values are generally somewhat smaller than those 

estimated from aquifer tests in these well fields. The hydraulic conductivity representing the 

Chaquehui formation and Puye Formation in the Guaje and Pajarito Mesa well fields is 

approximately half that estimated from aquifer tests. The hydraulic conductivity representing 

the Tesuque Formation in the western part of the Los Alamos well field is about half of the 

average aquifer-test value and, in the eastern part, one-seventh of the average aquifer-test value. 

This is not an unusual feature of regional models where the size of cells may span local barriers 

to flow such as faults and changes in lithologic character; thus, hydraulic-conductivity values 

specified for the model may be to some degree a result of model simplicity. Additionally, aquifertest analyses generally assume full penetration of the aquifer, which is not true of any of the 

wells tested. Finally, aquifer tests generally do not last longer than several days or weeks, 

whereas the hydrographs used for model adjustment are decades long. This longer history 

allows more time for the development of drawdown response to barriers within the aquifer.

28
106'15' COLUMN

10 15

I__________I

i .,-- f'Z-:':'°/7//N<-

"' '" ^^ ^~T^ /' - -" ';/ / \i // j 

30-

R. 6 B. R. 7 E. R. 8 E. 

EXPLANATION

HYDRAULIC-CONDUCTIVITY VALUES FOR LAYERS 2 AND 3 ARE THE SAME AS SHOWN FOR LAYER 1 EXCEPT AS FOLLOWS:

0123 MILES 

I 

0.3 FOOT PER DAY (LAYERS 2 AND 3) 

0.3 FOOT PER DAY (LAYER 3)

0123 KILOMETERS || 1 1 [ [ 2 FEET p£R DAY (LAYERS 2 AND 3)

0.2 FOOT PER DAY (LAYERS 2 AND 3) 

0.7 FOOT PER DAY (LAYER 3)

fmi HYDRAULIC-CONDUCTIVITY BOUNDARY FOR LAYER 1 

6 HYDRAULIC-CONDUCTIVITY VALUE, IN FEET PER DAY

Figure 11. --Hydraulic-conductivity values for layers 1-3.

29
106'15' COLUMN

106°00 

20

m "WB^^^^F -. T^-t ^'W""^"* n X

~ DA/-^-, O f\V O* ^ *r? -9 \

" -^ Of ""^*>«a^ ^U ^O *x "~ ^ < - V '' TP ^ O^'v:^K 'i ^"\ * \

\ \-J> X-^LV- ' . N >,* CO - ) ^ V

\ \^ - V*J^^^vSg*HINO ..' ,J ^ \

\ =%V V | X ^>^ESA^O <i t

30-

R. 6 E

i i i r 

0123

EXPLANATION 

HYDRAULIC-CONDUCTIVITY VALUES FOR _T~ HYDRAULIC-CONDUCTIVITY BOUNDARY FOR LAYER 4

! 3, MILES LAYER 5 ARE THE SAME AS THOSE SHOWN

^MPTPR* FOR LAYER 4, EXCEPT IN PATTERNED AREA 0.1 HYDRAULIC-CONDUCTIVITY VALUE, IN FEET PER DAY

MLUMbibHb WHERE VALUE IS 0.3 FOOT PER DAY

Figure 12.-Hydraulic-conductivity values for layers 4 and 5.

30
1 2 3

106°15' 

4567

COLUMN NUMBER 106TJO' 

89 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

36

00

CC 

LLJ

m

o

CC

35

45

R. 6 E. R. 7 E. R. 8 E. R. 9 E. R. 10

5 MILES

01 2345 KILOMETERS

EXPLANATION 

CONSTANT-FLOW BOUNDARY

CONSTANT-HEAD BOUNDARY

HEAD-DEPENDENT 

FLOW BOUNDARY

Figure 13.-Boundary conditions represented in layer 1 of the model 

(modified from McAda and Wasiolek, 1988, fig. 9).

31
Specific Yield and Storage Coefficients

Specific yield and storage coefficients were virtually identical to those of McAda and 

Wasiolek (1988). In this model, the storage coefficients of layers 2-8 were derived by multiplying 

layer thickness times a specific storage of 1 x 10"6 per foot. The total storage of both models is 

very similar; adding the specific yield of 0.15 plus the storage coefficients of layers 2-4 of McAda 

and Wasiolek gives a sum of 0.153, whereas this model has a sum of 0.1554 representing the same 

aquifer thickness in eight layers.

Initial Condition and Time Periods

A steady-state condition was used as the initial condition for the transient simulation. As in 

McAda and Wasiolek (1988), the ground-water system was assumed to be at steady state at the 

beginning of 1947, the beginning time of the transient simulation. (Municipal ground-water 

withdrawals began at about that time.) As in McAda and Wasiolek, subsequent stress periods 

were 1 year long to facilitate the use of annual ground-water-withdrawal data. MODFLOW 

allows for respecification of ground-water withdrawals each stress period, although the stress 

period may be subdivided into time steps, at which time model-derived values such as hydraulic 

heads can be reported (McDonald and Harbaugh, 1988, chap. 8, p. 3). This model used 46 stress 

periods to carry the simulation through the end of 1992. No annual ground-water-withdrawal 

data were available for 1993, but a 20-year projection was made from the end of 1992 to the end 

of 2012. The projection was made using one additional stress period of 20 equal time steps.

Boundary Conditions

Specified-head, specified-flow, and head-dependent flow boundary conditions were used 

in this model, as in McAda and Wasiolek (1988). At a specified-head boundary, hydraulic head is 

maintained and the flow is proportional to gradient and hydraulic conductivity. At a specifiedflow boundary, flow is maintained while the head is proportional to flow and hydraulic 

conductivity. At a head-dependent flow boundary, flow is simulated as a function of the 

difference between the hydraulic head simulated for the aquifer and a specified head 

representing a source or sink such as a river. For the purposes of the following discussion, these 

general boundary conditions are subdivided and described more specifically. A constant-head 

boundary is defined for this report as a specified-head boundary that is held constant throughout 

the time simulated. Similarly, a constant-flow boundary is a specified-flow boundary that is held 

constant throughout the simulation, whereas the term "specified flow" designates a flow that 

might be specified at varying levels through the simulation to represent discharge from a well, 

subsurface inflow, or recharge. Areal recharge is a type of specified-flow boundary at which the 

flow per unit area is specified in units of length/time (for example, acre-feet per acre per year) 

and the quantity entering the cell is calculated as the product of the specified value and cell area. 

A no-flow boundary is a specific instance of a constant-flow boundary. A no-flow boundary is 

the default condition next to the edge of the model or next to the edge of the area where model 

cells are active (fig. 9).

32
Constant ground-water recharge and discharge

Ground-water recharge and discharge are represented in the model as constant-head, 

constant-flow, areal-recharge, no-flow, and head-dependent flow boundaries. These boundary 

conditions, shown in figure 13, are approximately the same as those of McAda and Wasiolek 

(1988), except that the specified flows representing recharge from the mountains on the west and 

flow to or from the sedimentary rocks to the south have slightly different values. Also, where 

McAda and Wasiolek have boundaries specified in layers 1 and 2, the model herein described 

has similar conditions specified in layers 1-5.

On the north side of the modeled area, a constant-head boundary simulated flow from or 

to the northern part of the Espanola Basin as in McAda and Wasiolek (1988). The boundary 

shown in figure 13 extended through layers 1-6. The heads specified in the lower layers were the 

same as in layer 1. Similarly, on the southwest, flow into the Santo Domingo Basin was simulated 

by a constant-head boundary in layers 1-6.

The constant-flow boundaries representing flow from the mountains along the east and 

west sides of the modeled area are in layer 1 only. The constant flows along the east side are the 

same as those of McAda and Wasiolek (1988). The constant flows along the west side were 

determined, as in McAda and Wasiolek, by first specifying the hydraulic heads in a preliminary 

steady-state simulation and then using the flows thus derived as constant flows in the 

subsequent steady-state and transient simulations that are described in this report. Rows along 

the east side totaled 20.9 cubic feet per second and, along the west side, totaled 10.1 cubic feet per 

second. Flows at individual model cells are listed in table 5 in supplemental information in the 

back of the report.

The constant-flow boundary representing flow to and from older sedimentary rocks along 

the south side of the modeled area was in layers 1-5. Constant flows there were also determined 

by specifying hydraulic heads in a prior steady-state simulation. Rows at individual model cells 

were both positive and negative (table 5 in supplemental information) and totaled -1.6 cubic feet 

per second. The negative sign denotes a net flow out of the modeled area along the south side. 

The constant-flow boundary was located in row 33 of layers 1-3 as shown in figure 13, and in 

row 32 in layers 4-5. An exception to the foregoing description of the south boundary was at 

model row 33, column 23 of layer 1 where a constant head was specified under steady-state 

conditions. The flow at the constant head was 0.125 cubic foot per second; under transient 

conditions no flow was simulated.

Constant flows representing recharge from streambeds along the east side of the basin and 

constant flows simulating springs at La Cienega are the same as those of McAda and Wasiolek 

(1988). Specified flows (variable) for the Santa Fe River are discussed in the following section.

Areal recharge is shown in figure 14. Recharge on the Pajarito Plateau and on the area of the 

Tesuque Formation outcrop was decreased to 0.02 during model adjustment as explained in the 

model adjustment section of this report. Recharge in the rest of the modeled area was the same as 

that of McAda and Wasiolek (1988).

The head-dependent flow boundaries representing streams are shown in figure 13. They 

are the same as those of McAda and Wasiolek.

33
106°15' 106 C 00'

R. 6 E. R. 7 E. R. 8 E.

4 5 MILES 

i__i

R. 9 E. R. 10 E.

IIirni 

012345 KILOMETERS

Figure 14.-Distribution of areal recharge in the model, in inches per year 

(modified from McAda and Wasiolek, 1988, fig. 13).

34
Variable ground-water withdrawals and recharge

Variable ground-water withdrawals and recharge were represented as specified-flow 

boundaries. Ground-water withdrawal rates at public-supply wells in the five well fields (fig. 8) 

were specified for each 1-year stress period as given in tables 6-10 in the supplemental data 

section of this report. Withdrawals were divided between model layers on the basis of the 

approximate depth of open intervals of the wells below the predevelopment potentiometric 

surface. For the purpose of this calculation, the predevelopment surface at each well was 

assumed to be the water-level altitude at the earliest measurement, except in the case of flowing 

wells where the predevelopment surface was assumed to be approximately at land surface. The 

percentage of pumpage assigned to each of layers 1-5 for each well is given in table 11 in 

supplemental information. No pumpage was assigned to layers 6-8 (more than 2,000 feet below 

the water table).

Ground-water withdrawals at domestic and other wells in the Espanola Basin were the 

same as those specified by Me Ada and Wasiolek (1988) for 1947-82 and were increased each year 

from 1983 to 1992 at the rate of increase of the population of Santa Fe County. The rate of 

population increase was estimated on the basis of 1980 and 1990 U.S. Census total county 

population values. Because these withdrawals from almost 200 wells scattered over the eastern 

part of the modeled area constituted no more than 10 percent of total ground-water withdrawals 

and because they were not in the Los Alamos-Buckman area of interest, no new sites were 

specified. Total withdrawal rates for each stress period at these wells are listed in table 12 in 

supplemental information.

Recharge along the Santa Fe River was simulated as specified flows by McAda and 

Wasiolek (1988, p. 23) because the river is not perennial over most of its length in the modeled 

area and the water table is below the riverbed. Recharge varied with time and was simulated 

with the specified flows given in McAda and Wasiolek (1988, tables 7 and 8), representing 

recharge from streamflow and sewage treatment-plant effluent for 1947-82. For 1983-92, recharge 

from streamflow was set equal to values given by McAda and Wasiolek (1988, table 7) for 

1978-82, and recharge of Santa Fe sewage treatment-plant effluent was set equal to 50 percent of 

reported ground- and surface-water withdrawals. The location of recharge from sewage 

treatment-plant effluent shifted downstream, reflecting changes in plant facilities. For 1983-84, 

recharge was divided equally among four model cells at row 27, columns 17 and 18, and row 28, 

columns 13 and 14. For 1985-92, recharge was divided equally between two model cells at row 

28, columns 13 and 14.

Changes in recharge along canyon streams on the west side of Pajarito Plateau were not 

simulated because the mechanism of recharge is not well known. If most recharge is by way of 

horizontal flow at depth from the Jemez Mountains, it probably does not change much in 

response to pumpage at well fields. This is probably also true if most recharge is by way of deep 

percolation along the Pajarito Fault Zone. Also, if most recharge is by way of leakage from 

perched alluvial aquifers in canyons near the mountain front, a substantial quantity of waterwould be in transit through the 1,000-foot-thick zone that is unsaturated elsewhere on the 

plateau. The change in recharge due to diversion of a surface stream might take decades to fully 

manifest itself on the main aquifer. For example, assuming a complete cessation of streamflow 

recharge of the perched aquifer, although some diminishment of recharge to the main aquifer 

might begin soon thereafter, the complete cessation of main aquifer recharge may not occur for a 

very long time. Similarly, the change in recharge due to establishment of a new or extended 

perched aquifer downstream from sewage treatment-plant outfall might also take decades to

35
fully manifest itself as new recharge to the main aquifer. In view of these uncertainties, the 

recharge along the Pajarito Fault Zone was held constant at about 10 cubic feet per second 

through the duration of the simulation.

Other Modifications

A few modifications were required to allow the McAda-Wasiolek (1988) model to work 

with eight layers. The simulated hydraulic head in layer 1 dropped below the specified bottom 

altitude of the layer at some model cells, resulting in the cell "going dry" and no flow being 

simulated through those cells. Because this occurred near the boundaries in the southern and 

eastern parts of the model away from the area of interest near Los Alamos and Buckman, two 

remedies were selected. At La Cienega, where springs were simulated as constant negative 

flows, the area with larger hydraulic conductivity was extended westward into the spring area. 

The increased hydraulic conductivity in cells where outflow is simulated prevented excessive 

lowering of the hydraulic head in those cells. These springs issue from highly permeable 

materials of limited areal extent, details that are not well simulated by a regional model with 

milewide cells. The second remedy was to increase the initial saturated thickness by respecifying 

the bottom altitude of layer 1 at row 30, column 13 to a value 30 feet lower than that of McAda 

and Wasiolek (1988). The bottom altitude was also lowered along the Sangre de Cristo Mountain 

front in row 12, column 25 and in row 27, columns 23 and 24 where the bottom altitude was 

lowered by 50 and 30 feet, respectively. These changes were not considered excessive because 

they resulted in a smoother bottom surface on layer 1 than that of McAda and Wasiolek. Cells 

going dry was probably more of a problem with the 200-foot-thick top layer than it had been 

with the 800-foot-thick layer.

Model Budget

The model budget balances at approximately zero (table 2) that is, inflow equals outflow 

where storage is considered to be part of inflow and outflow. Under steady-state conditions, 

there is no storage change. Under transient conditions, water may be simulated as going into 

storage at one location and coming out of storage in another. Thus storage is listed in table 2 

under both headings, inflow (positive values) and outflow (negative values).

The constant-head boundary on the north side of the model did not adversely affect 

simulated drawdowns because the flows at the boundary did not change greatly during the time 

simulated. From steady state through the projection, inflow from the constant-head boundary 

increased and outflow decreased by amounts totaling about 0.3 cubic foot per second or 

0.4 percent of the total budget, which is not considered significant.

To show the simulated source of water withdrawn from wells, table 3 lists items from the 

model budget that change with time. Items that appear in table 2 under both inflow and outflow 

headings were combined in table 3, which shows net flows for storage, north boundary, 

southwest boundary, and rivers. Items that were constant through time in table 2 are not shown 

in table 3. Specified flows simulating recharge along the Santa Fe River ("sewage recharge" 

and "Santa Fe River" in table 2) were combined as "Santa Fe River recharge" in table 3.

36
Table 2.-Model budget

[All flows in cubic feet per second; apparent discrepancies in the 

tenths place are caused by rounding]

Budget item

Inflow 

Storage

Constant head

North boundary

Southwest boundary

South boundary

Specified flow

Pa jar it o boundary

Sangre de Cristo bed

South boundary

Sewage recharge

Santa Fe River

Other boundaries

Total specified flow

Areal recharge

Head dependent (rivers)

Total inflow

Outflow

Storage

Constant head

North boundary

Southwest boundary

Specified flow

Los Alamos field

Guaje field

Pajarito-Otowi field

Buckman field

Santa Fe field

Private wells

South boundary

Other boundaries

Total specified flow

Head dependent (rivers)

Total outflow

Steady state

0.0

1.9

0.1

0.1

10.1

20.9

0.6

0.0

7.5

10.1

49.2

4.8

1.3

57.4

0.0

-3.8

-12.1

0.0

0.0

0.0

0.0

0.0

0.0

-2.3

-6.5

-8.8

-32.7

-57.4

Stress 

period 46 

(1993)

15.5

2.0

0.1

0.0

10.1

20.9

0.6

6.9

2.2

10.1

50.8

4.8

1.3

74.5

-4.5

-3.7

-12.1

-0.1

-2.0

-4.4

-3.3

-2.9

-1.5

-2.3

-6.5

-23.0

-31.3

-74.6

Stress period 47 

(2013) Guaje 

alternative

12.6

2.0

0.0

0.0

10.1

20.9

0.6

6.9

2.2

10.1

50.8

4.8

1.3

71.6

-2.6

-3.7

-12.1

0.0

-1.6

-4.8

-3.3

-2.3

-1.5

-2.3

-6.5

-22.3

-31.0

-71.6

Stress period 47 

(2013) 

Pa jari to-Otowi 

alternative

12.7

2.0

0.0

0.0

10.1

20.9

0.6

6.9

2.2

10.1

50.8

4.8

1.3

71.6

-2.7

-3.7

-12.1

0.0

0.0

-6.4

-3.3

-2.3

-1.5

-2.3

-6.5

-22.3

-30.9

-71.7

37
Table 3. Model budget items that change with time

[All flows in cubic feet per second; apparent discrepancies in the

tenths place are caused by rounding]

Stress Change

Change Stress period 47 from

from period 47 (2013) Guaje to

steady (2013) Pajarito Pajarito

Stress state to Guaje -Otowi -Otowi

Steady period 46 stress alterna- alterna- alternastate (1993) period 46 tive tive tive

Storage (net) 0.0

Constant head

North boundary (net) -1.9 

Southwest boundary(net) -12.1 

South boundary 0.1

Specified flow

Santa Fe River recharge 

Los Alamos field 

Guaje field 

Pajarito-Otowi field 

Buckman field 

Santa Fe field 

Private wells 

Total withdrawals 

from wells

11.1

-1.7

-12.1

0.0

11.1

0.2

0.0

-0.1

10.0

-1.7

-12.0

0.0

10.0

-1.7

-12.0 

0.0

7.5

0.0

0.0

0.0

0.0

0.0

0.0

0.0

9.1

-0.1

-2.0

-4.4

-3.3

-2.9

-1.5

-14.2

1.6

-0.1

-2.0

-4.4

-3.3

-2.9

-1.5

14.2

9.1

0.0

-1.6

-4.8

-3.3

-2.3

-1.5

-13.5

9.1

0.0

0.0

-6.4

-3.3

-2.3

-1.5

-13.5

o.o

-0.0 

0.0 

0.0

0.0 

0.0 

1.6 

1.6 

0.0 

0.0 

0.0 

-0.0

Areal recharge

Head dependent 

(rivers, net)

4.8 

-31.3

4.8 

-29.9

0.0 

1.4

4.8 

-29.6

4.8 

-29.6

0.0 

0.0

The third column of numbers in table 3 shows the change from steady state to stress period 46 

flows. The specified 14.2 cubic feet per second withdrawn from wells is made up mainly by a 

simulated 11.1 cubic feet per second from storage, 1.6 cubic feet per second additional recharge 

along the Santa Fe River, and 1.4 cubic feet per second capture from rivers. The effects of 

individual wells or well fields is not indicated.

A comparison of the budget (table 2) with that of Me Ada and Wasiolek (1988, p. 36) reveals 

that the total budget for steady-state conditions is 16.4 cubic feet per second less than that of 

McAda and Wasiolek Most of the difference is in the Pajarito boundary, which is 8.5 cubic feet 

per second less, and areal recharge, which is 5.8 cubic feet less than that of McAda and Wasiolek. 

These smaller flow values are consistent with smaller values of hydraulic conductivity.

38
Model Adjustments

The general goal of model adjustment was to make model-derived values of hydraulic 

head and streamflow match measured values while keeping the simulated system properties 

reasonable in view of the foregoing discussion of geohydrology. Simulated system properties 

that were adjusted were recharge, hydraulic conductivity, specific yield, and storage.

System Properties Used for Comparison

Measured hydraulic heads and estimated streamflow gains were used for comparison with 

model-derived values. The objective of model adjustment was to minimize the average 

difference between measured and model-derived hydraulic heads and especially to match 

model-derived fluctuations in hydraulic head with measured fluctuations, as explained in the 

following discussion.

The gain in flow of the Rio Grande between Otowi and Cochiti may be between 10 and 

30 cubic feet per second on the basis of various estimates. A model-derived value was 13 cubic 

feet per second under steady-state conditions for the upper three-fourths of the reach from 

Otowi Bridge to Cochiti Pueblo, which is within the modeled area.

Measured hydraulic heads were divided into several groups. One group of hydraulic heads 

comprised those values that McAda and Wasiolek (1988) considered to be approximately 

representative of predevelopment (assumed to be steady-state) conditions plus eight additional 

values also considered to represent predevelopment conditions. Of these 184 hydraulic heads 

2 represented layer 2,8 represented layer 3, and 7 represented layer 4; the remainder represented 

layer 1. The mean difference between these 184 measured hydraulic heads and steady-state 

model-derived values was 16 feet, and the standard deviation of these differences was 67 feet. 

These statistics may be compared with those of McAda and Wasiolek (1988, p. 35) for 

176 measured hydraulic heads with a mean difference of 17.2 feet and standard deviation of 

57.5 feet.

A second group of hydraulic heads comprised 53 values measured during November 1976 

to April 1977 and was considered to represent the water table at the beginning of 1977; a third 

group comprised 60 values measured during November 1992 to April 1993 and was considered 

to represent the water table at the beginning of 1993. The 1977 and 1993 groups were plotted on 

maps for comparison with model-derived potentiometric surfaces (contours) for layer 1. The 

model-derived potentiometric surface for the 1977 transient-state simulation is shown in figure 

15; the map for 1993 (fig. 16) is similar except in the well fields. These groups were also used in 

statistical comparisons (table 13 in supplemental information).

Of a total of 297 hydraulic-head values representing steady state, 1977, and 1993, the 

arithmetic mean difference between measured and model-derived hydraulic heads was 11.7 feet. 

This indicates that the differences were more positive than negative, or that the model-derived 

potentiometric surfaces generally were higher than those measured. The mean of the absolute 

values of the differences was 53.4 feet. As explained by McAda and Wasiolek (1988, p. 35), the 

differences between measured and model-derived hydraulic heads result from the inability of 

the model to represent the details of aquifer variability in the area. Also, the measured hydraulic 

head, representing a composite over the entire screened interval of a well at a given location, 

may not represent the point coinciding with the center of the three-dimensional model cell. 

Because gradients are 50 to 100 feet per mile, it may be unrealistic to expect a much better match 

of model-derived to measured hydraulic heads. Model evaluation is discussed in a following 

section.

39
106"I5

COLUMN

R. 6E. R. 7E.

0123 MILES

0123 KILOMETERS

 6700

EXPLANATION

MODEL-DERIVED POTENTIOMETRIC CONTOURInterval 100 feet

o 6,534 WELL AND MEASURED HYDRAULIC HEAD, 

IN FEET ABOVE SEA LEVEL

Figure 15.~Model-derived potentiometric surface for layer 1 and measured hydraulic heads

for 1977.

40
106'15' COLUMN

36' 

00

5 ~

10 -

15

O 

DC

35' 

45

20 -

25

30 -

R. 6 E. R. 7E.

0123 KILOMETERS

06,114

EXPLANATION

MODEL-DERIVED POTENTIOMETRIC CONTOUR-- 

Interval 100 feet

WELL AND MEASURED HYDRAULIC HEAD, IN 

FEET ABOVE SEA LEVEL

Figure 16.-Model-derived potentiometric surface for layer 1 and measured hydraulic heads for 1993.

41
A fourth group of hydraulic heads comprised a history of measured hydraulic heads at 

specific wells. Hydraulic heads in this group were plotted as hydrographs for comparison with 

model-derived hydrographs. Many of the wells having hydrographs are production wells, 

completed over intervals that span two or more layers. In this case, comparison is made to the 

layer that represents the middle of the completed interval. Only nonpumping water levels were 

used to construct the hydrographs. Matching the hydrographs was the first priority during 

model adjustments. Locations of wells having hydrographs are shown in figure 17. The main 

objective of hydrograph comparison was to match annual and longer term fluctuations. A 

secondary objective was to match the absolute value of hydraulic heads, although, as previously 

explained, this could be difficult because the model-derived values are for cell centers, not for 

exact well locations.

Hydrographs shown in figures 18-22 feature two main curves. The solid curve shows the 

model-derived hydraulic heads. The dashed curve is the same as the solid curve except that it is 

offset vertically to pass through the first measured hydraulic head. In some cases, the dashed 

curve helps to assess the comparison between measured and model-derived fluctuations. The 

measured hydraulic heads are shown as circles. Model-derived hydraulic heads are projected 

after 1993. In each hydrograph, the main curve continues through 2013 using the Guaje 

alternative. A branch off the main curve was projected using the Pajarito-Otowi alternative. The 

alternatives and projections are explained and discussed in a subsequent section of this report.

Wells in the Los Alamos well field are shown in figure 18A-G, proceeding from east to west. 

Model-derived curves generally are higher than measured values. The fluctuations of the modelderived curves generally match the measured values, which tend to be similar for the entire field, 

and probably are a manifestation of overlapping cones of depression in the area. The fluctuations 

of the same model-derived curve (layer 3, row 10, column 11) better match the measured values 

at LA-2 (fig. 18C) than at LA-3 (fig. 18D), indicating that some features of the hydrologic system 

are not well represented by the model at the location of LA-3.

Wells in the Guaje well field are shown in figure 19A-G, again proceeding from east to west. 

The model-derived curves tend to be higher than the measured values for the east end of the 

field and lower for the west end. A recovery of hydraulic heads during the late 1960's is not as 

apparent in the measured values for wells G-l, G-1A, G-2, and G-5 (fig. 19A-C, and F) as in the 

model-derived curves. The hydraulic-head recovery during the late 1960's is apparent in 

measured and simulated values for well G-6 (fig. 19G), again indicating that some local features 

of the hydrologic system are not well represented at the locations of G-l, G1A, G-2, and G-5. 

Otherwise, the fluctuations of the model-derived curves well match the measured values.

Test and production wells in the vicinity of the Pajarito Mesa well field are positioned on 

facing pages in figure 20 approximately in their relative field locations: hydrographs for 

northern wells are at the top of the pages. Test wells are designated by LANL with the letters TW 

or DT, and Pajarito Mesa production wells are designated with the letters PM. The modelderived curves are higher than measured values on the northeast at wells TW-1 and PM-1 

(fig. 20D and H), but lower at neighboring wells TW-3 and PM-3 (fig. 20C and G). Conversely, the 

model-derived curve is lower than measured values at well TW-4 and higher at neighboring 

wells. A partial explanation is that well TW-4 is located on a relatively steep gradient upslope 

from the center of the model cell. The relatively gentle declines of the model-derived curves well 

match the measured values for about half of the wells. At well TW-1 (fig. 20D) the markedly 

higher hydraulic heads measured in the 1990's may reflect very local conditions at the site 

(Environmental Protection Group, 1993, p. VII-22). Also, at well PM-1 (fig. 20H) early measured 

hydraulic heads are considered to represent a time of partial well development (Alan Stoker, Los 

Alamos National Laboratory, Environmental Protection Group, oral commun., 1993).

42
106-15' COLUMN

36' 

00 '

5 ~

10 -

15

o

QC

35' 

45

20

25

30 -<

i = -2 i: -x 1 _ 1

': : " r I " ^ *v --' -^ \ \ s -i,\..^ i

i i :tt~7 * : J ^^rVh "--L \ ^ ;

j i /' h M \

__^.. jj.__tf-"^_(j.......__i...\_\r:_\

-"Y'T^ I---^-^' ! i i\

R. 6 E. R. 7 E. R. 8E.

1 2 3 MILES 

i i i

EXPLANATION

I I i i 

0123 KILOMETERS

PM-2

o WELL AND WELL NAME OR NUMBER

Figure 17.--Location of wells having hydrographs. 

43
A 2 10 11 355301 1060922 Lfl-1 B 4 10 11 355301 1060920 LR-1B

5,700

5,650

5,600

5,550

5,500

5,450

5f650 

5,600 

5,550 

5500

UJ

> 

UJ

1940 1950 1960 1970 1980 1990 2000 2010 2020

C 3 10 11 355304 1060936 LR-2

1940 1950 1960 1970 1980 1990 2000 2010 2020

D 3 10 11 355303 1060947 LR-3

5700

UJ

UJ 5,500

± 5450

D

UJ

I

O

' 1940 1950 1960 1970 I960 1990 2000 2010 2020 

E 3 10 10 355238 1061025 Lfi-6

5,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

F 4 11 10 355218 1061102 Lfi-5

rr 5700 

Q

1 5650

5,600

5,550

5,800

5,750

5,700

5,650

< 5,700

rr

P 5,650

5,600

5,550

1940 1950 1960 1970 I960 1990 2000 201 0 2020

G 4 11 9 355205 1061131 LR-4

1940 1950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION

LATITUDE

COLUMN / LONGITUDE ROW /

NUMBER

4119 355205 1061131 LA-4

 MODEL-DERIVED HYDROGRAPH USING 

GUAJE ALTERNATIVE AFTER 1992

 - MODEL-DERIVED HYDROGRAPH USING 

PAJARITO-OTOWI ALTERNATIVE 

AFTER 1992

1940 1950 1960 1970 1980 1990 2000 2010 2020

MODEL-DERIVED HYDROGRAPH USING 

GUAJE ALTERNATIVE AFTER 1992-Offset 

to pass through first measured hydraulic head

MODEL-DERIVED HYDROGRAPH USING

PAJARITO-OTOWI ALTERNATIVE AFTER 1992- 

Offset to pass through first measured hydraulic 

head

MEASURED HYDRAULIC HEAD

Figure 18.--Hydrographs for wells in the Los Alamos well field, north-central 

New Mexico (location of wells shown in fig. 17).

44
499 355407 1061146 6-1 399 355415 1061158 G-lfl

5850

5800

5750

5,700

5650

1940 1950 i960 1970 1980 1990 2000 2010 2020

5,850

5,800

5,750

5,700

5,650

1940 1950 1960 1970 1980 1990 2000 2010 2020

88 355422 1061210 6-2

LU

5 D 4 8 8 355433 1061241 6-3

5,900

LU 

CO

5,850

O

CD 5,800

LU 5,750 

LU

5,600

1940 1950 1960 1970 1980 1990 2000 2010 2020

5,700

1940 1950 1960 1970 1980 1990 2000 2010 2020

Q 

LU

O 5,950 

Hi =)

< 5,900 

Q

^C 5850 

5,800 

5,750

387 355435 1061314 6-4

1940 1950 1960 1970 1980 1990 2000 2010 2020

LU

I

O 5,950

_l

=)

^ 5,900

Q

1 5,850

5,800

5,750

F 387 355450 1061339 6-5

387

5,950

355439 1061404 6-6

5,900

5,850

5,800

5,750

1940 1950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION 

LAYER

LATITUDE 

COLUMN / LONGITUDE

/ LOCAL WELL NUMBER

387 355450 1061339 G-5

1940 1950 1960 1970 1980 1990 2000 2010 2020

 MODEL-DERIVED HYDROGRAPH USING 

GUAJE ALTERNATIVE AFTER 1992

 MODEL-DERIVED HYDROGRAPH USING 

PAJARITO-OTOWI ALTERNATIVE 

AFTER 1992

 MODEL-DERIVED HYDROGRAPH USING

GUAJE ALTERNATIVE AFTER 1992-Offset 

to pass through first measured hydraulic head

........... MODEL-DERIVED HYDROGRAPH USING

PAJARITO-OTOWI ALTERNATIVE AFTER 

1992--Offset to pass through first 

measured hydraulic head

o MEASURED HYDRAULIC HEAD

Figure 19.--Hydrographs for wells in the Guaje well field, north-central New Mexico 

(location of wells shown in fig. 17).

45
ON

Tl ca" c

CD

o o

0} CQ

if

-K TJ

 'oS'

^_

 xl O

Q.

3 O

HYDRAULIC HEAD, IN FEET ABOVE SEA LEVEL

cn 

j>-

CD

CD O

m

o 

en

 H

s: i

CD

HYDRAULIC HEAD, IN FEET ABOVE SEA LEVEL

to to ID to 

o ro *> o>

oo 

cn oO

cn 

xj

XJO

I CD

CD 

COO

cn

Ul

cn 

cn
C 1 11 5 355224 1061531 TW~3 D 1 11 8 355213 1061301 TW~1

6,000

5,950

5,900

5,850

5,800

19-10 1950 i960 1970 1980 1990 2000 2010 2020

HI 

HI

UJ

w

UJ> 

oCO

G 4 11 6 355147 1061431 PM-3

5,950

5,900

UJ 5,850

Ul

LL

5,800 "-1

1940 1950 1960 1970 1980 1990 2000 2010 2020

K 4 12 5 355060 1061555 PM-4

5,950

5,900

5,850

5,800

Ul 

> 

UJ

UJ

Ul

> 

O 

m

ui ui U_

Ul I

o

or 

o

1940 1950 1960 1970 1980 1990 2000 2010 2020

M 4 13 5 355017 1061542 PM-2

5,950

5,900

5,850

5,800

5,900 

5,850 

5,800 

5750 

5/00

1940 1950 1960 1970 1980 1990 2000 2010 2020

H 4 12 7 355134 1061329 PM-1

5,880

5,860

5,840

5,820

5,800

5,780

5,760

5740

1940 1950 1960 1970 1980 1990 2000 2010 2020

LAYER

1940 1950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION

COLUMN LATITUDE mwrminp ROW / ^ LONGITUDE 

/ / /^ ^^ ^ LOCAL WELL NUMBER

4 13 5 355017 1061542 PM-2

MODEL-DERIVED HYDROGRAPH USING 

GUAJE ALTERNATIVE AFTER 1992

MODEL-DERIVED HYDROGRAPH USING PAJARITOOTOWI ALTERNATIVE AFTER 1992

MODEL-DERIVED HYDROGRAPH USING 

GUAJE ALTERNATIVE AFTER 1992»Offset 

to pass through first measured hydraulic head

MODEL-DERIVED HYDROGRAPH USING

PAJARITO-OTOWI ALTERNATIVE AFTER 1992-- 

Offset to pass through first measured hydraulic head

MEASURED HYDRAULIC HEAD

Figure 20.--Hydrographs for wells in the Pajarito Mesa well field, north-central New Mexico 

(location of wells shown in fig. 17)-Concluded.

47
A 414123549311060833 18.07.01.224 B 1 13 11 355000 1060928 19.07 36.311 SF2C

3.0UU

 I

^ 5,700

UJ

UJ

W 5,600

UJ

O 

m

< 5,500

h- 1' 

UJ 

HI 

U-

: \ fl i\ ;

I / 1/ I

i /Jlf 1 1 f\l *|B M

: f ;7 A/ i

; V ',' :

HO 1950 1960 1970 1980 1990 2000 2010 20

_J 5,450

UJ

UJ

-1 5,400 

Ul

w

Uj 5,350 

O

m

^ Ot^UU

20 (_ 15 

UJ 

Ul 

UL

o

w

"*

1

HO 1950 1960 1970 1980 1990 2000 2010 20

z

Q

UJ I

0

1

cc

Q

I

C 3

5,700

5,600

5,500

5,400

5,300 

c;5nn

13 11 355000 1060928 19.07.36.311 SF2

\ ' VM [ > __ -

^ wVV . -

o

o

O

5700 -

*s

^ 5,600 

Q

X 5,500 -

5,400 L.

1940 1950 I960 1970 1980 1990 2000 2010 2020 1940 1950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION

LAYER

QOLUMN

LATITUDE

LONGITUDE

LOCAL WELL NUMBER

513113550001060928 19.07.36.311 SF2A

O

MODEL-DERIVED HYDROGRAPH USING 

GUAJE ALTERNATIVE AFTER 1992

MODEL-DERIVED HYDROGRAPH USING 

GUAJE ALTERNATIVE AFTER 1992-Offset 

to pass through first measured hydraulic head

MEASURED HYDRAULIC HEAD

Figure 21.--Hydrographs for wells in the Buckman well field, north-central New Mexico 

(location of wells shown in fig. 17).

48
UJ

>

LLJ

LU 

CO

UJ 

>

O 

CD

hLU 

LU 

U.

A 1 24 22 354052 1055821 17.09.27.211

6,850

6,800

6,750

6,700

6,650

6,600

19401950 I960 1970 1960 1990 2000 2010 2020

C 1 26 20 353923 1055915 17.09.33.432

6,560

6,540

6,520

6,500

6,480

6,460

6,440

B 3 25 22 354013 1055806 17.09.27.441

6,900

6,800 

6,700 

6,600 

6,500 L*

UJ 

>

UJ

19401950 1960 1970 I960 1990 2000 2010 2020

D 1 26 21 353907 1055837 16.09.03.121 RXB

19401950 1960 1970 I960 1990 2000 2010 2020 ±

LU

CO

LU

>

O

CO

«<

LU

LU

LJL

z

6,700

6,650

6,600

6,550

6,500

: ---V --, ' ' ' ' : : a**^*o^~~--~___ :

0 ° :

,_

-

[ ^^^- ^_ J

19401950 1960 1970 I960 1990 2000 2010 20

UJ

I

O

_l 

ID 

< 

DC 

O

E 2 26 22 353845 1055741 16.09.02.312

6,750

6,700

6.650

6600

UJ

I

O

cc

Q

F 1 27 17 353803 1060310 16.08.12.131

6,260

19401950 1960 1970 1980 1990 2000 2010 2020

6,240

6,220

6,200

6,180

6,160

6,140

19401950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION

LAYER

ROW

COLUMN

LATITUDE

LONGITUDE

/ LOCAL WELL NUMBER 

/ /

2 26 22 353845 1055741 16.09.02.312

MODEL-DERIVED HYDROGRAPH USING 

GUAJE ALTERNATIVE AFTER 1992

MODEL-DERIVED HYDROGRAPH USING 

GUAJE ALTERNATIVE AFTER 1992-Offset 

to pass through first measured hydraulic head

MEASURED HYDRAULIC HEAD

Figure 22.--Hydrographs for wells in the Santa Fe area, north-central New Mexico 

(location of weils shown in fig. 17).

49
G 1 27 19 353838 1060020 16.09.05.412 H 1 28 13 353725 1060644 16.08.17.212

6,600

_i 

UJ

Uj 6500

_i

UJ

w

UJ 5400 

O

CD

H_ 6.300 

UJ 19 

LU

 _ (jtMMfDO- _ _ _ _

-

.... 1 .... 1 .... 1 ... i . TTTTTTTTT-T-r-H^ . . .

40 1950 1960 1970 1980 1990 2000 2010 20

£6,300

UJ

UJ UJ

1 W 6.200

QUJ

< CO 

OC < 6,100

X UJ

u_

Z 6.000 

20 ~ U

 1 1 1 ' 1 1 1 1 ' 

- - - -^fgpojSSitiUS <mrt<Qf o

-

i i i i i i i

340 1950 1960 1970 1980 1990 2000 2010 20

I 1 29 18 353636 1060210 16.08.13.444

O

6,260

6240

6220

CC 6200 

O '

^ 6,180 

6,160 

6140

6120

1940 1950 I960 1970 1980 1990 2000 2010 2020

EXPLANATION

LAYER

ROW

COLUMN

LATITUDE LONGITUDE

1 29 18 353636 1060210 16.08.13.444

MODEL-DERIVED HYDROGRAPH USING 

GUAJE ALTERNATIVE AFTER 1992

- ------ MODEL-DERIVED HYDROGRAPH USING

GUAJE ALTERNATIVE AFTER 1992-Offset 

to pass through first measured hydraulic head

o MEASURED HYDRAULIC HEAD

Figure 22.--Hydrographs for wells in the Santa Fe area, north-central New Mexico 

(location of wells shown in fig. 17)--Concluded.

50
Fluctuations in model-derived curves do not match fluctuations in measured values during the 

late 1970's and early 1980's at wells PM-4 and PM-2 (fig. 20K and M), although the overall slope 

of the curve at PM-2 matches well. Model-derived curves decline more quickly than seen in the 

general trend of measured values at wells DT-5A and DT-10 (fig. 201 and J), located southwest of 

the field, but the slope of the model-derived curve well matches the trend of measured values at 

well DT-9.

Hydrographs for four wells in the Buckman well field are shown in figure 21. Modelderived curves appear to be generally higher than measured values. Because most of the wells in 

the Buckman field flowed, however, initial hydraulic heads are not known. Model-derived 

fluctuations match measured fluctuations for well 18.07.01.224 (fig. 21 A). Although this is not the 

case for the other three wells, the limited duration of the record makes the comparison difficult to 

evaluate. One possible explanation for the lack of an abrupt decline in the model-derived curve 

to match that evident in the measured values could be that ground-water withdrawals for 

1988 were largely from well B-l, near the observation well nest, but were assigned to the entire 

well field (as previously described). The effect of incorrectly assigning withdrawals within the 

Buckman field would be that the simulated potentiometric surface within the Buckman field 

would be different than might have been observed; however, the effect beyond the Buckman 

field should not be great.

Hydrographs for wells in the Santa Fe area are shown in figure 22. The model-derived 

curves match the measured values about as well as those of McAda and Wasiolek (1988, fig. 20). 

An exception is the model-derived curve for well 16.08.17.212 (fig. 22H), which diverges sharply 

from the measured values starting in 1983. Similarly, the model-derived curve for well 

16.08.12.131 (fig. 22F) has a precipitous drop, whereas the short record of measured values does 

not drop. This probably indicates that the model representation of sewer-plant effluent recharge 

is incorrect. Because these mismatches seem to be limited to the localities of wells not in the area 

of interest for this study, data necessary to make corrections were not collected.

System Properties Adjusted

Properties adjusted were recharge, mainly along the Pajarito Fault Zone; hydraulic 

conductivity near Los Alamos; and specific yield and storage. Hydraulic conductivity was the 

primary focus of adjustment.

Recharge

Recharge along the Pajarito Fault Zone was adjusted by changing the constant-head values 

specified in the steady-state simulation that was used to generate values for specified flows in 

subsequent steady-state and transient simulations. Although specified head values were 

increased from those specified by McAda and Wasiolek (1988) by an average of 141 feet in rows 

7-18, columns 1 and 2, the resultant specified recharge in rows 2-20 along the Pajarito Fault Zone 

of 10 cubic feet per second was less than the McAda and Wasiolek value of 19 cubic feet per 

second. The lesser flow rate results from hydraulic-conductivity values smaller than those of 

McAda and Wasiolek in much of the area except in the Pajarito Mesa well field.

Recharge along the Pajarito Fault Zone was simulated only in layer 1. This is consistent 

with recharge occurring locally as indicated by the altitude of recharge previously discussed. If 

recharge were to occur at some distance from the fault zone, it might enter the modeled area at 

some depth. This possibility is addressed in the sensitivity analysis.

51
Model-derived hydraulic heads were higher in the north-central part of the eight-layer 

model than in the four-layer model. As a partial correction for this, recharge in the northern part 

of the model was decreased on the basis of the zero recharge estimate of Anderholm (1994).

Hydraulic conductivity near Los Alamos

Hydraulic-conductivity values in the northwestern part of the model were adjusted to 

those shown in figures 11-12 to simulate measured hydraulic heads. Primarily the objective was 

to make model-derived hydrographs match measured hydraulic heads (figs. 18-22). In some 

cases, fluctuations in the model-derived curve well match fluctuations in the measured hydraulic 

heads, but the model-derived curve is too high (fig. 19B) or too low (fig. 20G), as indicated by the 

difference between the solid and dashed curves. The model-derived fluctuations at a site seemed 

to be controlled mainly by the hydraulic conductivity in the immediate vicinity. Whenever 

possible, the hydraulic conductivity was generalized to a wider area. For example, the hydraulicconductivity value for the Buckman well field, which is in the Tesuque Formation, seemed to 

work for the Tesuque in much of the northwestern part of the model, including the western part 

of the Los Alamos well field. However, at the east end of the Los Alamos well field, a smaller 

value of hydraulic conductivity was required to simulate the larger fluctuations there 

(fig. 18A-C) than in the western part of the field (fig. 18E-G).

The general configuration of the potentiometric surface (fig. 6) in the vicinity of the Pajarito 

Plateau was simulated under steady-state conditions (fig. 23) with higher hydraulic-conductivity 

values in the middle of the plateau than on the east or west sides of the plateau. This 

configuration of hydraulic conductivity results in a steeper potentiometric surface on the east 

and west sides of the plateau than in the middle. At first, the hydraulic conductivity representing 

the Chaquehui formation and Puye Formation was set at 10 feet per day in a strip from the Guaje 

well field on the north to the test wells south of the Pajarito Mesa well field (fig. 17). During 

adjustment, the values near the Guaje field (figs. 11-12) were decreased to simulate greater 

fluctuations in the hydrographs. Also, the eastward gradient across the Guaje field (figs. 2,6, and 

23) was more closely approximated by hydraulic-conductivity values in the Guaje field that were 

more Dearly equal to those on the downgradient side. (As previously explained, steady-state 

conditions were assumed to represent predevelopment conditions that were assumed to have 

existed before 1947.) On the south end, the hydraulic conductivity representing the Chaquehui 

and Puye was reduced to slow the extension of drawdown cones into the area of test wells 

DT-5A, DT-9, and DT-10.

Specific yield and storage

Specific-yield and storage values were adjusted on a modelwide basis. Slight 

improvements in the simulation of some hydrographs were found to be balanced by poorer 

simulation of other hydrographs. Without a good geologic basis to specify storage values on a 

cell-by-cell basis, specific yield and storage were finally specified at approximately the same 

values as those of McAda and Wasiolek (1988).

52
106'15' COLUMN

ii ii i > r' i if 17 i ,i ill

30 ~

R. 6 E.

0123 MILES i i i i

0123 KILOMETERS

R. 7 E

-6700

EXPLANATION

MODEL-DERIVED POTENTIOMETRIC CONTOURInterval 100 feet. Datum is sea level

Figure 23.-Steady-state potentiometric surface for layer 1.

53
Simulated Response to Projected Withdrawals

The main purpose of these simulations was to assess the effects of renewing the Guaje well 

field by replacing the six existing wells with four new wells in the same field (the "Guaje 

alternative") or of retiring the Guaje field and increasing withdrawals from other fields. The most 

likely alternative to withdrawing water from replacement wells in the Guaje field is increasing 

withdrawals from wells in the Pajarito Mesa and Otowi fields (the "Pajarito-Otowi alternative"). 

In either case, total production from LANL wells is assumed (Alan Stoker, written commun., Feb. 

11,1994) to be 1.5 billion gallons per year.

The Guaje alternative is as follows:

~ 25 percent from the Guaje field, divided equally between each of four new wells;

 25 percent from the Otowi field, of which 25 percent is from well O-l and 75 percent from 

O-4; and

 50 percent from the Pajarito Mesa field, divided in the same proportions as in 1992.

The Pajarito-Otowi alternative is as follows:

 33 percent from the Otowi field, of which 33 percent is from O-l and 67 percent from O-4;

and 

~ 67 percent from the Pajarito Mesa field, divided in the same proportions as in 1992.

Two projections were made, one for each of the above-described alternatives. For the 

projections, one stress period with 20 equal 1-year time steps was added to the transient 

simulation. All ground-water withdrawals outside the LANL well fields were simulated at the 

1992 rates as were other specified recharge/discharge rates. In figures 18-21, the model-derived 

hydrographs diverge after the beginning of 1993, reflecting the difference between the two 

alternatives. The solid line represents the Guaje alternative and the chain-dot line represents the 

Pajarito-Otowi alternative. As previously explained, the dashed line is the same as the solid line, 

offset vertically to pass through the first measured hydraulic head; the dotted line diverges from 

the dashed line as the chain-dot line diverges from the solid line. At wells near the eastern end of 

the Los Alamos well field (fig. 18A-E), no divergence between the two alternatives is visible at 

the scale shown. At the western end of the Los Alamos field (fig. 18G), projected hydraulic heads 

are about 20 feet higher with the Guaje alternative. This reflects the relative closeness of the 

Otowi and Pajarito Mesa fields to the LA-4 site. In the Guaje field (fig. 19), projected hydraulic 

heads are as much as 50 feet lower with the Guaje alternative, and in the Pajarito Mesa field 

(fig. 20), hydraulic heads are as much as 12 feet higher with the Guaje alternative, compared to 

the Pajarito-Otowi alternative. In the Buckman field (fig. 21), the divergence between the two 

alternatives is barely visible, and in the Santa Fe area (fig. 22), no divergence is visible at the 

scales shown. Although the difference between the two alternatives was not great at the scale 

shown in hydrographs for the Buckman field, projected hydraulic heads were 2 feet higher at 

layer 5, row 13, column 11 with the Guaje alternative because the Buckman field is closer to the 

Pajarito Mesa field than to the Guaje field.

Purtymun and Johansen (1974, fig. 3) showed a well site at a point about 4 miles north of 

the Guaje well field, although no records of wells in that vicinity are in the U.S. Geological 

Survey data base. At that point, located at model row 4, column 6, model-derived hydraulic 

heads for layer 1 were as follows:

5977.28 feet, under steady-state (initial) conditions; 

5975.18 feet, for 1993;

5974.12 feet, for 2013 given the Pajarito-Otowi alternative; and 

5973.63 feet, for 2013 given the Guaje alternative.

54
Thus, the model-derived drawdown was about 2 feet by 1993 and an additional 1 foot by 2013 

given the Pajarito-Otowi alternative. The Guaje alternative results in a model-derived 

drawdown of 0.5 foot more than the Pajarito-Otowi alternative at this location. The net flow 

(difference between inflow and outflow) to the head-dependent flow boundaries that represent 

the Rio Grande, Rio Pojoaque, and Rio Tesuque decreases through the transient simulation. 

During the part of the simulation that represents 1947-93, net flow decreases from 31.3 cubic feet 

per second under steady-state conditions to 29.9 cubic feet per second, a decrease of 1.4 cubic feet 

per second (table 3). During the 20-year projection, 1993-2013, simulated net flow to these 

streams declines an additional 0.3 cubic foot per second with both alternatives.

Sensitivity Tests

The model is much simpler than the ground-water system that it represents. Therefore, any 

simulated responses of the ground-water system need to be used with caution. However, given 

its limited purpose, the model is considered to be adequate for making a preliminary projection 

of the effects of replacing the Guaje well field with new wells in approximately the same location. 

Although system properties used in the model are assumed to approximate those of the groundwater system, these properties are not known with certainty.

Sensitivity tests were used to assess the effects that the use of different values of system 

properties would have on: (1) the overall match between measured and model-derived hydraulic 

heads, (2) the model-derived hydrographs in each well field, and (3) the projected difference 

between the Guaje and Pajarito-Otowi alternatives. In each of the following tests, a system 

property was changed and the result compared with the unchanged model. For the purpose of 

comparison, the unchanged model described in previous sections of this report is termed the 

"standard" model, and in this discussion, all hydrographs and hydraulic heads are model 

derived unless specified as measured. All tests included running a steady-state reinitialization 

except those involving only storage values.

The overall match between measured and model-derived hydraulic heads is assessed on 

the basis of the average difference between the measured and model-derived values calculated 

in four ways (table 4). The arithmetic mean in table 4 is the sum of all differences, positive and 

negative, divided by the number of differences. The arithmetic mean greater than zero indicates 

that the model-derived potentiometric surface is generally too high. The mean absolute is the 

arithmetic mean of the absolute values of the differences. The mean absolute shows the overall 

goodness of fit without allowing positive and negative values to cancel each other, but it does not 

reveal the bias of the model-derived potentiometric surface. The median also reveals the overall 

goodness of fit without showing extreme differences, whereas the root-mean square accentuates 

the extreme differences. The root-mean square is the square root of the mean of the squares of the 

differences. Of these averages, the mean absolute is considered the best indicator of the relative 

goodness of each of the changed models.

55
Table 4.-Average of differences between measured and model-derived hydraulic

heads for the standard and each sensitivity test, in feet

[K is horizontal hydraulic conductivity; K' is vertical hydraulic

conductivity; NW is northwest]

Number of Arithmetic Mean 

Sensitivity test differences1 mean absolute

Standard

Move Pajarito fault-boundary

specified flows to layer 4

Move Pajarito fault boundary to

layer 4 using greater flows

K in NW times 0.5 (K/K' same as

standard)

K in NW times 1.5 (K/K' same as

standard)

K/K'=100 (K' times 0.5)

K/K'=40 (K' times 1.25)

Standard

Storage times 0.667

Storage times 1.33

297

297

297

297

297

297

297

113

113

113

11

10

18

11

11

39

4

4

0

6

.7

.8

.0

.4

.8

.8

.6

.6

.9

.7

53.

54.

57.

53.

53.

60.

53.

54.

56.

53.

4

0

6

8

6

6

6

2

2

2

Median

16.

14.

28.

13.

18.

35.

13.

14.

11.

14.

0

3

2

8

4

7

2

9

4

9

Root-mean 

square

69

69

73

69

69

80

69

70

73

68

.5

.8

.0

.7

.5

.7

.6

.5

.7

.8

 " The larger number includes both steady-state and transient data sets. The 

smaller number includes only the transient data set.

A hydrograph representing each well field is presented for each of the following sensitivity 

tests, and their general effect on model-derived hydraulic heads in each well field is discussed. In 

each graph the standard includes two projections (after 1992). The Guaje alternative in the 

projection is represented as a solid line. The chain-dot offshoot from the solid line projected after 

1992 is the same except that the Pajarito-Otowi alternative is used in the projection. The effect of 

choosing the Guaje alternative over the Pajarito-Otowi alternative projected by the standard 

model is shown as the difference between the chain-dot line and the solid line. The changed 

model is shown by the dashed line representing the Guaje alternative and by a dotted offshoot 

representing the Pajarito-Otowi alternative. The effect of choosing the Guaje alternative 

projected by the changed model is compared to that of the standard by comparing the difference 

between the dotted and dashed lines with the difference between the chain-dot and solid lines. 

For clarity in the following discussions, the difference between alternatives is consistently 

described as the effect of selecting the Guaje alternative.

Pajarito Fault Zone Recharge

Recharge along the Pajarito Fault Zone was moved from layer 1 to layer 4 in two tests. In 

the first test, the specified-flow values of the standard, which are all in layer 1, were reassigned to 

layer 4. (That is, no recharge was specified for layer 1.) Although the overall fit of measured and 

model-derived hydraulic heads was not greatly affected, the mean absolute difference (table 4) 

was 0.6 foot greater than that of the standard. Fluctuations in hydrographs (fig. 24) of the 

changed model were the same as those of the standard model in the Los Alamos, Guaje, and 

Buckman well fields (fig. 24A, B, and D), where the dashed hydrographs (changed model) are 

indistinct from the solid hydrographs (standard). Hydraulic heads were lower in the Pajarito

56
Mesa field (fig. 24C), especially at test wells (not shown) on the upgradient side of the well field. 

At well TW-4, hydraulic head was 70 feet lower in the changed model than in the standard 

model; at well TW-8,14 feet lower; at well DT-5A, 20 feet lower; at well DT-9,14 feet lower; and 

at well DT-10,18 feet lower. Thus, the model-derived hydrograph of the changed model fit the 

measured values better than that of the standard at well TW-8 but not at well TW-4. The 

projected effect of the Guaje alternative was the same as that of the standard. The effect of this 

test on hydrographs for the Santa Fe area was not visible at the scale shown (fig. 24E).

In a second test, the specified-head boundary that had been used in a preliminary steadystate simulation to determine specified-flow recharge to layer 1 in the standard was used in a 

similar manner (a preliminary steady-state simulation) to determine specified-flow recharge to 

layer 4. (Again, no recharge was specified for layer 1.) The newly derived specified-flow values 

were somewhat larger than those of the standard. The overall fit of measured and model-derived 

hydraulic heads was not as good as that of the standard; the mean absolute difference (table 4) 

was 4.3 feet greater than that of the standard. Fluctuations in hydrographs (fig. 25) of the 

changed model were the same as those of the standard model. Because hydraulic heads were 

generally higher than those of the standard, however, the fit of measured and model-derived 

values was generally worse than that of the standard except for well TW-4 (not shown). The 

projected effect of the Guaje alternative was the same as that of the standard. The effect of this 

test on hydrographs for the Santa Fe area is a slight increase in hydraulic heads, barely visible at 

the scale shown (fig. 25E). It was concluded that the estimated effects of the Guaje alternative 

probably do not depend on the simulated vertical location of recharge along the Pajarito Fault 

Zone.

Hydraulic Conductivity

Sensitivity testing was done on both horizontal and vertical hydraulic conductivity. For 

horizontal hydraulic conductivity, two tests were compared to the standard:

a. Values in northwest part of the model decreased by 50 percent (K in NW times 0.5) 

b. Values in northwest part of the model increased by 50 percent (K in NW times 1.5)

For vertical hydraulic conductivity, two tests were compared to the standard: 

a. Values in the model decreased by 50 percent (K/K' = 100) 

b. Values in the model increased by 25 percent (K/K' = 40)

The results of the test in which assigned values of horizontal hydraulic conductivity were 

0.5 times those of the standard was a mean absolute difference 0.4 foot greater than that of the 

standard (table 4). Fluctuations in hydrographs (fig. 26) were generally much greater for this test 

than for the standard in the Buckman, Los Alamos, Guaje, and Pajarito Mesa well fields. The 

greater fluctuations did not fit the measured values as well as did those of the standard. The 

projected effect of the Guaje alternative was about 200 percent of that of the standard in the Los 

Alamos well field (fig. 26A-C) and 152 percent in the Buckman well field. Although the effect of 

the Guaje alternative was not visible at the scale shown in hydrographs for the Buckman field, 

projected hydraulic heads were 3.1 feet higher at layer 5, row 13, column 11 with the Guaje 

alternative than with the Pajarito-Otowi alternative, as compared to a difference of 2.0 feet using 

the hydraulic-conductivity values of the standard. The effect of this test on hydrographs for the 

Santa Fe area was a slight increase in hydraulic heads, barely visible at the scale shown (fig. 26E).

57
A 4 11 10 355218 1061102 Lfl-5 B 3 9 9 355415 1061158 6-lfl

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5,600

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1940 1950 1960 1970 1980 1990 2000 2010 2020 < 1940 1950 1960 1970 1980 1990 2000 2010 2020

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340 1950 1960 1970 1980 1990 2000 2010 20

224

20

1940 1950 1960 1970 1980 1990 2000 2010 2020

ROW

EXPLANATION

LATITUDE

LONGITUDE

WELL NAME

4116 355147 1061431 PM-3

STANDARD USING GUAJE ALTERNATIVE AFTER 1993

_..._._ _ STANDARD USING PAJARITO-OTOWI ALTERNATIVE 

AFTER 1993

RECHARGE IN LAYER 4 USING GUAJE 

ALTERNATIVE AFTER 1993

RECHARGE IN LAYER 4 USING PAJARITO-OTOWI 

ALTERNATIVE AFTER 1993

MEASURED HYDRAULIC HEAD

Figure 24.--Effect of moving specified-flow recharge of the Pajarito Fault Zone from 

layer 1 to layer 4 (location of wells shown in fig. 17).

58
A 4 11 10 355218 1061102 LR-5

5.800

5,700

^600

LLJ

I

o

QC 

Q

5,500

B 399 355415 1061158 G-lfl

5,850

1940 1950 1960 1970 1980 1990 2000 2010 2020

LLJ

> 5,800

LLJ

< 5750

LLJ

CO

LU 5,700

O 

CO 

< 5,650

C 4116 355147 1061431 PM-3

6,000

5,950

5,900

5,850

5,800

LLJ 

LLJ

LLJ

I

O

1940 1950 1960 1970 1980 1990 2000 2010 2020

D 4 14 12 354931 1060833 18.07.01.224

5,900

5,800

5700

QC

Q 5600

1940 1950 1960 1970 1980 1990 2000 2010 2020

5,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

E 32522 3540131055806 17.09.27.441 C

6,900

6,800

6,700

6,600

6,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION

COLUMN LATITUDE 

ROW 7 / LONGITUDE

WELL NAME

4116 355147 1061431 PM-3

STANDARD USING GUAJE ALTERNATIVE AFTER 1993

 -- STANDARD USING PAJARITO-OTOWI ALTERNATIVE 

AFTER 1993

 INCREASED RECHARGE IN LAYER 4 USING GUAJE 

ALTERNATIVE AFTER 1993

 INCREASED RECHARGE IN LAYER 4 USING PAJARITO-OTOWI

ALTERNATIVE AFTER 1993

0 MEASURED HYDRAULIC HEAD

Figure 25.--Effect of moving specified-flow recharge of the Pajarito Fault Zone from layer 1 

to layer 4, using larger flow values (location of wells shown in fig. 17).

59
A A 11 10 355218 1061102 Lfl-5 B 3 9 9 355415 1061158 G-1R

5.BOO

5,700

5,600

5,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

UJ 

UJ

UJ 

CO

UJ

o

UJ 

1X1 u_

LU

I

o

_l

3

cr Q

T.

UJ&

UJ 

CO

UJ

o

CO

UJ 

UJ

u_

5,900

5800

5,700

5,600

5,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

11 6 355147 1061431 PM-3 D 4 14 12 354931 1060833 18.07.01.224

5,950

5.900

5,850

5.800

5,750

Q 5,900

< 

UJ

I

O 5,800

_l

<

Q 5,700

>- 

I

5600

1940 1950 1960 1970 1980 1990 2000 2010 2020

5,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

E 3 25 22 354013 1055806 17.09.27.441c

6,900

6,800

6,700

6,600

6,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION

COLUMN LATITUDE

LONGITUDE

WELL NAME

4116 355147 1061431 PM-3

 STANDARD USING GUAJE ALTERNATIVE AFTER 1993

_..._ _.. _ STANDARD USING PAJARITO-OTOWI ALTERNATIVE AFTER 1993

 SMALLER HORIZONTAL HYDRAULIC-CONDUCTIVITY VALUES 

USING GUAJE ALTERNATIVE AFTER 1993

 SMALLER HORIZONTAL HYDRAULIC-CONDUCTIVITY VALUES

USING PAJARITO-OTOWI ALTERNATIVE AFTER 1993

o MEASURED HYDRAULIC HEAD

Figure 26.--Effect of using smaller horizontal hydraulic-conductivity values in the 

northwestern part of the model (location of wells shown in fig. 17).

60
The sensitivity test in which horizontal hydraulic-conductivity values were increased to 

1.5 times those of the standard had the following results: the mean absolute difference was 0.3 

foot greater than that of the standard (table 4). Fluctuations in hydrographs (fig. 27) were 

generally less for this test than for the standard in the Buckman, Los Alamos, Guaje, and Pajarito 

Mesa well fields. The lesser fluctuations fit the measured values better than those of the standard 

at some sites in the Guaje and Pajarito Mesa fields (fig. 27B and C), but worse than those of the 

standard at some sites in the Los Alamos and Buckman fields (fig. 27A and D). The lesser 

fluctuations did not fit the measured values as well as did those of the standard at well G-2 in the 

Guaje field and at wells PM-2 and PM-4 in the Pajarito Mesa field (not shown). The slope of the 

potentiometric surface across the Guaje field (not shown) was less for this test than for that of the 

standard and did not fit the slope in the measured values as well as did that of the standard. The 

projected effect of the Guaje alternative was about 70 percent of that of the standard in the Los 

Alamos, Guaje, and Pajarito Mesa well fields and 79 percent in the Buckman well field. The effect 

of this test in the Santa Fe area is a slight decrease in hydraulic heads, barely visible at the scale 

shown (fig. 27E).

The test in which vertical hydraulic-conductivity values (K') were decreased throughout 

the model by a factor of 0.5 times those of the standard (K/K' = 100) had the following results: 

the mean absolute difference (table 4) was 7.2 feet greater than that of the standard. Fluctuations 

in hydrographs (fig. 28) were greater than those of the standard, and hydrographs generally did 

not fit the measured values as well as did those of the standard (fig. 28). Hydraulic heads were 

greater than those of the standard in the Los Alamos and Buckman well fields (fig. 28A and D), 

and less than those of the standard in the Guaje and Pajarito Mesa fields (fig. 28B and C); this 

generally did not improve the fit of measured and model-derived heads. Hydraulic heads were 

greater than those of the standard in the Santa Fe area (fig. 28E). The projected effect of the Guaje 

replacement wells was about 115 percent of those of the standard in the Los Alamos, Guaje, and 

Pajarito Mesa well fields and 144 percent in the Buckman well field.

The results of the test in which vertical hydraulic-conductivity values were increased 

throughout the model by a factor of 1.25 times those of the standard (K/IC = 40) were mixed. 

Although the resulting arithmetic mean was less than that of the standard, the resulting mean 

absolute difference (table 4) was 0.2 foot greater than that of the standard. Fluctuations in 

hydrographs (fig. 29) were less than those of the standard, and although hydrographs fit the 

measured values better than those of the standard at a few sites (fig. 29C), they did not fit the 

measured values as well at other sites (fig. 29E). Hydrographs for the Los Alamos and Guaje well 

fields were little different from those of the standard (fig. 29A and B). Hydraulic heads were 

lower than those of the standard in the Santa Fe area (fig. 29E). The projected effect of the Guaje 

alternative was about 95 percent that of the standard in the Los Alamos, Guaje, and Pajarito 

Mesa well fields and 89 percent that of the standard in the Buckman well field. It was concluded 

that because these tests generally did not yield improvements in the comparison between 

measured and model-derived hydraulic heads, the hydraulic-conductivity values of the 

standard are plausible.

Storage

Sensitivity testing was done on storage values throughout the model. In one test storage 

values were decreased by a factor of 0.667, and in the other test storage values were increased by 

a factor of 1.33. Statistics were calculated on the basis of transient (1977 and 1993) data because 

storage does not apply to steady-state conditions.

61
A 4 11 10 355218 1061102 Lfl-5 B 3 9 9 355415 1061158 6-1R

5,800

5/00

5.600

5,500

LLJ 

>

HI

UJ 

CO

UJ

o

CO

HI

T.

O

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cr Q

n:

1940 1950 1960 1970 1980 1990 2000 2010 2020

UJ

UJ

O

5

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5.850

5,800

5750

5,700

5.650 u

1940 1950 1960 1970 1980 1990 2000 2010 2020

C 4 11 6 355147 1061431 PM-3 D 4 14 12 354931 1060833 18.07.01.224

5.950

5.900

5,850

5,800

O 5,800

<

HI

T.

§ 5,700

5,600

1940 1950 1960 1970 1980 1990 2000 2010 2020

5,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

E 3 25 22 354013 1055806 17.09.27.441C

6.900

6,800

6.700

6J500

6,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

LAYER

ROW

EXPLANATION

LATITUDE

LONGITUDE COLUMN / 

^ \ / / ^

4116 355147 1061431 PM-3

WELL NAME

STANDARD USING GUAJE ALTERNATIVE AFTER 1993 

STANDARD USING PAJARITO-OTOWI ALTERNATIVE AFTER 1993

LARGER HORIZONTAL HYDRAULIC-CONDUCTIVITY VALUES 

USING GUAJE ALTERNATIVE AFTER 1993

LARGER HORIZONTAL HYDRAULIC-CONDUCTIVITY VALUES 

USING PAJARITO-OTOWI ALTERNATIVE AFTER 1993

MEASURED HYDRAULIC HEAD

Figure 27.--Effect of using larger horizontal hydraulic-conductivity values in the 

northwestern part of the model (location of wells shown in fig. 17).

62
A 4 11 10 355218 1061102 Lfl-5 B 3 9 9 355415 1061158 6-lfl

111 

>

LU

LU 

CO

LU

o

CO

LU 

LU

o

5.800

5.700

5600

5.500

1940 1950 1960 1970 1980 1990 2000 2010 2020

C 4 11 6 355147 1061431 PM-3

5,950

5.900

5,850

5800

5750

5,850

5,800

5,750

LU

W 5.700 

UJ

O

8 5650

1940 1950 1960 1970 1980 1990 2000 2010 2020

D 4 14 12 354931 1060833 18.07.01.224

Q" 5,900 

<

LU

I

5800

QC 5,700 

Q

5,600

1940 1950 1960 1970 1980 1990 2000 2010 2020

5500

1940 1950 1960 1970 1980 1990 2000 2010 2020

QC 

Q

I

E 3 25 22 354013 1055806 17.09.27.441C

6900

6,800

6,700

6,600

6,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION

LAYER __... LATITUDE

\ R?W COLUMN / LONGITUDE 

\ | / / ^

4116 355147 1061431 PM-s"

WELL NAME

 STANDARD USING GUAJE ALTERNATIVE AFTER 1993

_._ ._ _ . STANDARD USING PAJARITO-OTOWI ALTERNATIVE AFTER 1993

 SMALLER VERTICAL HYDRAULIC-CONDUCTIVITY VALUES 

USING GUAJE ALTERNATIVE AFTER 1993

........... SMALLER VERTICAL HYDRAULIC-CONDUCTIVITY VALUES

USING PAJARITO-OTOWI ALTERNATIVE AFTER 1993

o MEASURED HYDRAULIC HEAD

Figure 28.--Effect of using smaller vertical hydraulic-conductivity values 

(location of wells shown in fig. 17). 

63
A 4 11 10 355218 1061102 Lfl-5 B 3 9 9 355415 1061158 B-lfl

5,800

5.700

5,600

o jo

5,850

LU 

> 

LU 

-I 5/50

< 

LU 

CO 5^00

>

 5,500 ' ' ' ' I ' ' ' ' ' i I i I i I O 5,650

> 1940 1950 1960 1970 1980 1990 2000 2010 2020 < 1940 1950 1960 1970 1980 1990 2000 2010 2020

£ C 4 11 6 355147 1061431 PM-3

LU 

LU D 4 14 12 354931 1060833 18.07.01.224

5.950

O 

m

5.900

LU 

LU 

LL

5.850

O

< 

LU

I

O

5.800

2 5,800

Q

< 

LU 

I

O

5/00

< 5.600

CC

Q

1940 1950 I960 1970 1980 1990 2000 2010 2020

5,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

E 3 25 22 354013 1055806 17.09.27.441C

6.900

6.BOO

6,700

6,600

6,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION

LAYER nn RW

LATITUDE

COLUMN LONGITUDE

WELL NAME

4116 355147 1061431 PM-3 

STANDARD USING GUAJE ALTERNATIVE AFTER 1993 

STANDARD USING PAJARITO-OTOWI ALTERNATIVE AFTER 1993

LARGER VERTICAL HYDRAULIC-CONDUCTIVITY VALUES 

USING GUAJE ALTERNATIVE AFTER 1993

LARGER VERTICAL HYDRAULIC-CONDUCTIVITY VALUES 

USING PAJARITO-OTOWI ALTERNATIVE AFTER 1993

MEASURED HYDRAULIC HEAD

Figure 29.--Effect of using larger vertical hydraulic-conductivity values 

(location of wells shown in fig. 17).

64
The test in which storage values throughout the model were decreased by a factor of 0.667 

had the following results: the mean absolute difference (table 4) was 2 feet greater than that of 

the standard. Fluctuations in hydrographs (fig. 30) were greater than those of the standard. 

Although a long-term trend of more drawdown than that of the standard resulted in an 

improved fit of model-derived to measured hydraulic heads at some locations in the Guaje field 

(fig. 30B), the same trend resulted in a poorer fit at other locations in the Pajarito Mesa field (fig. 

30C). Hydrographs for the Los Alamos and Buckman fields were little different from those of the 

standard (fig. 30A and D). Some hydrographs in the Santa Fe area fit the measured values better 

than those of the standard (fig. 30E). The projected effect of the Guaje alternative was about 

105 percent that of the standard in the Los Alamos, Guaje, and Pajarito Mesa well fields and 

107 percent in the Buckman well field.

Statistical results of the test in which storage values throughout the model were increased 

by a factor of 1.33 were mixed. The mean absolute difference (table 4) was 1.0 foot less than that 

of the standard, indicating an overall better fit of model-derived and measured values, a 

conclusion supported by the other averages except the mean. Fluctuations in hydrographs 

(fig. 31) were less than those of the standard. Hydrographs for the Los Alamos, Guaje, and 

Buckman well fields were little different from those of the standard (fig. 31A, B, and D). 

Although at some locations, such as well PM-3 (fig. 31C), a long-term trend of less drawdown 

than that of the standard resulted in a better fit of model-derived to measured heads, the same 

trend resulted in a poorer fit at other sites such as wells PM-1 and PM-2 (not shown). 

Hydrographs for the Santa Fe area (fig. 31E) generally did not fit measured values as well as 

those of the standard. The projected effect of the Guaje alternative was about 95 percent that of 

the standard in the Los Alamos, Guaje, and Pajarito Mesa well fields and 97 percent in the 

Buckman well field. It was concluded that the effects of the Guaje and Pajarito-Otowi alternative 

projected by the standard could be overestimated as a result of the storage values used. The 

storage values of the standard could be too small. Larger storage values would tend to reduce 

drawdowns and dampen the effect of either alternative.

Predictive Capability

The standard model reproduces measured hydraulic heads and head fluctuations fairly 

well and should be useful for predicting the drawdown effects of the Guaje alternative. Modelderived hydraulic heads of the standard model match measured values better than any of the 

sensitivity tests except the test where greater storage was simulated. Although the effect of the 

Guaje alternative predicted by the standard is a very small part of drawdown at the Buckman 

well field, greater storage would tend to result in less effect from ground-water withdrawals 

than that of the standard.

Use of this model for other purposes such as the estimation of ground-water-flow path 

lines for a chemical transport model would not be appropriate because the rrodel is much 

simpler than the geohydrologic system. Although fluctuations in measured hydrographs are 

approximately matched, the model-derived hydrographs are often substantially above or below 

the measured hydrographs. That is, the differences between the solid and dashed lines in figures 

18-22 are often as much as 50 feet. This is probably because the aquifer is heterogeneous, and the 

rate of ground-water movement is greater than average in the more permeable zones, leading to 

paths that are more complex than the paths that the model simulates. The model does not 

account for the structure of the Tesuque Formation or detailed variations in hydraulic 

conductivity of the Chaquehui formation and Puye Formation and of the basaltic rocks that are 

buried within the Chaquehui and Puye. Also, the location and rate of recharge are not known, 

though recharge is thought to occur somewhere near the western side of the Pajarito Plateau.

65
A 4 11 10 355218 1061102 Lfi-5 B 3 9 9 355415 1061158 G-lfi

5.800

5,700

5,600

5,500

5850

5,800

LU 

CO

LU

O

CO

5,750

5,700

LU 

LU

LU 

CO

o

CD

LU 

LU

LU 

X

1950 1960 1970 1980 1990 2000 2010 2020

5650

I- 1940 1950 1960 1970 1980 1990 2000 2010 2020

LU

LU

C 4 11 6 355147 1061431 PM-3 D 4 14 12 354931 1060833 18.07.01.224

5950

5.900

5,850

5.800

5,750

< 5800 

LU

X

O

I 5,700

QC 

O

X

5,600

1940 1950 1960 1970 1980 1990 2000 2010 2020

5,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

tr 

o

X

E 3 25 22 354013 1055806 17.09.27.44lC

6,900

6800

6,700

6.600

6.500

1940 1950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION

WELL NAME

4116 355147 1061431 PM-3

 STANDARD USING GUAJE ALTERNATIVE AFTER 1993 

_..._..._..._.... STANDARD USING PAJARITO-OTOWI ALTERNATIVE AFTER 1993

 SMALLER STORAGE VALUES USING GUAJE 

ALTERNATIVE AFTER 1993

 SMALLER STORAGE VALUES USING PAJARITO-OTOWI

ALTERNATIVE AFTER 1993

o MEASURED HYDRAULIC HEAD

Figure 30. --Effect of using smaller storage values (location of wells shown in fig. 17).

66
A 4 11 10 355218 1061102 Lfl-5 B 3 9 9 355415 1061158 6-lfl

5800

5700

5,600

jt>

5,850

5,800

LU

> 5,700

O

CO

<c

5,650

<*«**>

UJ 

W

UJ 

>

O

CO

LU 

UJ 

UL

UJ

I

O

3 

<

CC 

Q

1S4Q 1950 1960 1970 1980 1990 2000 2010 2020 h- 1940 1950 1960 1970 1980 1990 2000 2010 2020

LU 

LU 

UL

6 355147 1061431 PM-3 4 14 12 354931 1060833 18.07.01.224

5,950

5900

5.BSO

5,800

Q 

LU

O

5,700

1940 1950 1960 1970 1980 1990 2000 2010 2020

< 5600

CC

Q

>-

1 5500

1940 1950 1960 1970 1980 1990 2000 2010 2020

E 3 25 22 354013 1055806 17.09.27.441C

6,900

6800

6,700

6,600

6,500

1940 1950 1960 1970 1980 1990 2000 2010 2020

EXPLANATION

ROW

COLUMN LATITUDE

LONGITUDE

LAYER LOCAL WELL NUMBER

\

414123549311060833 18.07.01.224

STANDARD USING GUAJE ALTERNATIVE AFTER 1993

STANDARD USING PAJARITO-OTOWI ALTERNATIVE 

AFTER 1993

LARGER STORAGE VALUES USING 

GUAJE ALTERNATIVE AFTER 1993

LARGER STORAGE VALUES USING PAJARITO-OTOWI 

ALTERNATIVE AFTER 1993

MEASURED HYDRAULIC HEAD

Figure 31.--Effect of using larger storage values (location of wells shown in fig. 17).

67
DATA NEEDS FOR AN IMPROVED UNDERSTANDING OF THE FLOW SYSTEM

Environmental considerations make contaminant transport modeling of the Pajarito 

Plateau in the vicinity of LANL a possibility. An improved understanding of the flow system 

would be desirable if a contaminant transport model were to be constructed. The data needs of a 

specific contaminant transport model would depend on the contaminant, the location of the 

contaminant source, the distance the contaminant has been transported by ground water, and the 

objectives of the transport model. However, a flow model would first need to be developed to 

provide a reliable approximation of flow path lines in the vicinity where a contaminant transport 

model might be attempted. Although the model described in this report is adequate for the 

purpose of distinguishing the effects of the Guaje and Pajarito-Otowi alternatives on hydraulic 

heads at the Buckman well field, a reliable simulation of ground-water-flow path fines for 

contaminant transport probably would require a better understanding of the hydrologic 

characteristics of the Pajarito Plateau and adjacent areas.

Determination of the location and quantity of recharge to the aquifer(s) of the Pajarito 

Plateau would be useful. Although estimates of the age and recharge altitude of water from 

production wells are useful evidence, water from production wells is likely to be a mixture of 

water from all strata from which the well withdraws water. Water from production wells could 

come by various flow paths, which would make conclusions about age and recharge altitude 

difficult and tenuous. The age and recharge altitude of water samples collected from discrete 

points in the three-dimensional flow field would be more useful for determining the location of 

recharge and rate of ground-water movement. Along with age and recharge altitude, horizontal 

and vertical gradients, saturated and unsaturated hydraulic-conductivity values, and degree of 

saturation in the vicinity of the Pajarito Fault Zone could help indicate the source of recharge. 

The magnitude of reported hydraulic-conductivity values of the Bandelier Tuff under saturation 

conditions would allow for recharge wherever a constant supply of water is available to 

maintain saturation. The Bandelier could be saturated beneath perennial streams where they 

enter the west side of the Pajarito Plateau. If recharge is substantial beneath perennial streams, 

then the location of a substantial part of recharge probably has changed because surface water 

has been diverted from perennial streams and reintroduced at points downstream from sewer 

plants. This change probably has not occurred suddenly because of storage in the thick 

unsaturated zone between the perched alluvial aquifers and the water table of the main aquifer. 

Thus, along streams two transient situations would exist: zones of decreasing recharge and zones 

of increasing recharge. On much of the area of the Pajarito Plateau, evapotranspiration could be 

about the same as precipitation, thus limiting recharge, and a substantial chloride buildup might 

be present in the soil and in the top of the Bandelier Tuff. A chloride buildup could be verified in 

the field at relatively low cost compared to other subsurface geologic investigations.

Accurate, long-term records of ground-water withdrawals and nonpumping hydraulic 

heads are valuable because they provide what is in effect a long-term aquifer test. Continued 

observations and record keeping are essential. Vertically integrated data derived from wells that 

are open over several aquifer zones are useful, but data more specific to thinner zones might be 

more conclusive.

Patterns of water-yielding characteristics within the Chaquehui formation, Puye 

Formation, and interbedded basaltic rocks would be useful. The zones of extreme (large or small) 

hydraulic conductivity would be of particular concern, whether in the main aquifer, perched 

aquifers, or zones located vertically between aquifers. For example, large zones of the basaltic 

rocks, if they are massive, could have very small hydraulic conductivity, porosity, and storage 

coefficient; depending on fractures, however, such zones could be penetrated by solutes more 

quickly than a porous medium having a similar hydraulic conductivity. Also, a consistent dip or 

orientation of the beds and lenses of the Chaquehui and Puye could result in anisotropy that

68
could affect the direction and rate of movement along flow paths. Any information on water 

quality, rock/water interactions, and penetration of tracers would be useful in refining concepts 

of the flow system.

Water-level, geologic, and aquifer-characteristic data for the northern extremity of the 

Pajarito Plateau (north of Los Alamos County), especially between the county line and Santa 

Clara Canyon, would be useful. Geohydrologic characteristics of that area, which lies adjacent to 

the Guaje well field, are almost completely unknown. On the basis of extremely sparse data, 

Purtymun and Johansen (1974, fig. 3) indicated a southward component of flow into Los Alamos 

County from that area.

The possible southward extent of the Chaquehui formation through the southern extremity 

of the Pajarito Plateau could have a bearing on flow paths because the Chaquehui is more 

permeable than the Tesuque Formation. For example, if the Chaquehui were to extend unfaulted 

southward past St. Peter's Dome toward the Santo Domingo Basin, the resulting changes in 

ground-water flow could affect flow path lines in other areas of the Pajarito Plateau.

An understanding of the Tesuque aquifer system east of the Pajarito Plateau would be 

needed to simulate reasonable boundary conditions for the main aquifer of the Pajarito Plateau. 

In approximate order of usefulness, improved understanding of streamflow gains along the Rio 

Grande, the dip on beds of the Tesuque Formation, the transient effects of Cochiti Reservoir 

(Lake) recharge estimates for the Tesuque, estimates of ground-water withdrawals north of Santa 

Fe, the destination of sewer-plant effluent in the Santa Fe area, and estimates of hydraulic 

conductivity and aquifer thickness south of Santa Fe would be useful.

The dip and extent of the Tesuque Formation could have a significant effect on flow paths. 

The westward-dipping beds could result in westward flow at depth beneath the eastern part of 

the Pajarito Plateau. The possible westward extent of the Tesuque beyond the Pajarito Fault Zone 

could allow for more flow across the Pajarito Fault Zone at depth than would be likely if rocks 

west of the Pajarito Fault Zone are less permeable than the Tesuque Formation.

SUMMARY AND CONCLUSIONS

The model of McAda and Wasiolek was modified in recognition of new geohydrologic 

interpretation and adjusted to simulate hydrographs in well fields in the Los Alamos area. 

Hydraulic-head drawdowns at the Buckman well field resulting from withdrawals at four 

scheduled replacement wells in the Guaje well field were estimated with the modified model. 

The Chaquehui formation (informal usage) is the main new feature of recent geohydrologic 

interpretations. The Chaquehui occupies a "channel" that was eroded or faulted into the 

Tesuque, and the Chaquehui is more permeable than the Tesuque. The Chaquehui is a major 

producing zone in the Pajarito Mesa well field and to a a lesser extent in the Guaje well field. 

Model modification included splitting the four layers of the McAda-Wasiolek model into eight 

layers to better simulate vertical ground-water movement. Minor adjustments were made in the 

La Cienega area to avoid having model-derived hydraulic heads lower than the bottom of the 

top layer. Otherwise, model modifications were limited as much as possible to the area of 

interest near Los Alamos and Buckman and consisted mainly of adjusting hydraulicconductivity values representing the Tesuque Formation, Chaquehui formation, and Puye 

Formation, and adjusting simulated recharge along the Pajarito Fault Zone west of Los Alamos. 

Initial adjustments of hydraulic conductivity near Los Alamos were based on recent geological 

interpretations of the Chaquehui and Puye. Adjustments of hydraulic conductivity and recharge

69
were based mainly on the simulation of fluctuations in measured hydraulic heads near Los 

Alamos and Buckinan. Storage values were adjusted but final values were approximately the 

same as those of the McAda-Wasiolek model. Although sensitivity testing seemed to indicate 

that storage values could be too small, larger storage values tended to decrease drawdowns and 

dampen the effect of the Guaje replacement wells. Variations of hydraulic conductivity and 

recharge used during sensitivity tests resulted in simulations that were not as good as the 

standard.

Two possible alternative plans for replacing Guaje well field production were suggested by 

LANL. In the first plan (Guaje alternative), four new wells would replace existing production 

wells in the Guaje field. In the second plan (Pajarito-Otowi alternative), the Guaje field would be 

retired and its former production would be made up by additional withdrawals from the Pajarito 

Mesa and Otowi well fields. A projection for each of these alternatives was made using the new 

eight-layer model. In the Guaje field, projected hydraulic heads were as much as 50 feet lower 

with the Guaje alternative, and in the Pajarito Mesa field, hydraulic heads were as much as 12 

feet higher with the Guaje alternative. At the western end of the Los Alamos well field, projected 

hydraulic heads were about 20 feet higher with the Guaje alternative; at the eastern end of the 

Los Alamos field, the effect of the Guaje alternative was much smaller. At the Buckman well 

field, projected hydraulic heads were about 2 feet higher with the Guaje alternative because the 

Buckman field is closer to the Pajarito Mesa field than to the Guaje field.

Ways of improving the understanding of the flow system include developing a more 

accurate representation of the structure and extent of the Tesuque Formation, Chaquehui 

formation, and Puye Formation of the Santa Fe Group and obtaining more detailed geologic and 

hydrologic characteristics of the Chaquehui formation and Puye Formation. Data that describe 

water chemistry, hydraulic head, and degree of saturation could be used to determine the 

location and quantity of recharge on the Pajarito Plateau, especially along the west side and in 

canyon bottoms. Chloride concentrations in soil at the top of the Bandelier Tuff could be used to 

verify the concept that evapotranspiration accounts for nearly all precipitation over a large area 

of the plateau.

70
REFERENCES

Abrahams, J.H., Jr., Weir, J.E., and Purtymun, W.D., 1961, Distribution of moisture in soil and nearsurface tuff on the Pajarito Plateau, Los Alamos County, New Mexico, in Geological Survey 

Research 196l: U.S. Geological Survey Professional Paper 424-D, p. 142-145.

Anderholm, S.K., 1994, Ground-water recharge near Santa Fe, north-central New Mexico: U.S. 

Geological Survey Water-Resources Investigations Report 94-4078,68 p.

Baltz, E.H., 1978, Resume of the Rio Grande Depression in north-central New Mexico, in 

Guidebook to Rio Grande rift in New Mexico and Colorado: Socorro, New Mexico Bureau 

of Mines and Mineral Resources Circular 163, p. 210-228.

Borton, R.L., 1968, General geology and hydrology of north-central Santa Fe County, New Mexico: 

New Mexico State Engineer Office Open-File Report, 21 p.

Budding, A.J., 1978, Gravity survey of the Pajarito Plateau, Los Alamos and Santa Fe Counties, 

New Mexico: Los Alamos Scientific Laboratory Informal Report LA-7419-MS, 15 p.

Environmental Protection Group, 1993 (August), Environmental surveillance at Los Alamos 

during 1991: Los Alamos National Laboratory Report LA-12572-ENV, variously paged.

Finch, ST., Jr., and Fleming, W.M., 1992, Recalibration of the USGS-SEO Santa Fe ground-water 

model using revised recharge estimates: John W Shomaker, Inc. consultant report prepared 

for the Santa Fe Metropolitan Water Board, 22 p.

Freeze, R.A., and Cherry, J.A., 1979, Groundwater: Englewood Cliffs, N.J., Prentice-Hall, 604 p.

Galusha, Ted, and Blick, J.C., 1971, Stratigraphy of the Santa Fe Group, New Mexico: American 

Museum of Natural History Bulletin, v. 144, article 1,127 p.

Griggs, R.L., 1964, Geology and ground-water resources of the Los Alamos area, New Mexico: 

U.S. Geological Survey Water-Supply Paper 1753,107 p., 1 pi.

Hearne, G.A., 1985, Mathematical model of the Tesuque aquifer system near Pojoaque, New 

Mexico: U.S. Geological Survey Water-Supply Paper 2205,75 p.

Johnson, A.I., 1967, Specific yield compilation of specific yields for various materials: U.S. 

Geological Survey Water-Supply Paper 1662-D, 74 p.

Kelley, V.C., 1978, Geology of Espanola Basin, New Mexico: Socorro, New Mexico Bureau of 

Mines and Mineral Resources Geologic Map 48, scale 1:125,000.

Lee Wilson and Associates, 1978, Santa Fe County water plan: Consultant report, variously paged.

Lohman, S.W, 1972, Ground-water hydraulics: U.S. Geological Survey Professional Paper 708, 

70 p.

Los Alamos National Laboratory, 1993, Installation work plan for environmental restoration, 

revision 3, November 1993: Los Alamos National Laboratory Report LA-UR-93-3987, 

variously paged.

Manley, Kim, 1978a, Cenozoic geology of Espanola Basin, in Guidebook to Rio Grande rift in New 

Mexico and Colorado: Socorro, New Mexico Bureau of Mines and Mineral Resources 

Circular 163, p. 201-210.

___1978b, Structure and stratigraphy of the Espanola Basin, Rio Grande rift, New Mexico: US. 

Geological Survey Open-File Report 78-667,24 p.

Me Ada, D.P., and Wasiolek, Maryann, 1988, Simulation of the regional geohydrology of the 

Tesuque aquifer system near Santa Fe, New Mexico: U.S. Geological Survey WaterResources Investigations Report 87-4056,71 p.

71
REFERENCES-Concluded

McDonald, M.G., and Harbaugh, A.W., 1988, A modular three-dimensional finite-difference 

ground-water flow model: Techniques of Water-Resources Investigations of the U.S. 

Geological Survey, book 6, chap. Al, variously paged.

Mourant, W.A., 1980, Hydrologic maps and data for Santa Fe County, New Mexico: New Mexico 

State Engineer Office Basic Data Report, 180 p., 2 pis.

Purtymun, W.D., 1984, Hydrologic characteristics of the main aquifer in the Los Alamos area; 

Development of ground-water supplies: Los Alamos National Laboratory Report LA-9957- 

MS,44p.

Purtymun, W.D., 1995, Geologic and hydrologic records of observation wells, test holes, test wells, 

supply wells, springs, and surface water stations in the Los Alamos area: Los Alamos 

National Laboratory Report LA-12883-MS, 339 p.

Purtymun, W.D., and Adams, Howard, 1980, Geohydrology of Bandelier National Monument, 

New Mexico: Los Alamos National Laboratory Informal Report LA-8461-MS, 25 p.

Purtymun, W.D., Becker, N.M., and Maes, Max, 1985, Water supply at Los Alamos during 1983: 

Los Alamos National Laboratory Progress Report LA-10327-PR, 39 p.

Purtymun, W.D., and Cooper, J.B., 1969, Development of ground-water supplies on the Pajarito 

Plateau, Los Alamos County, New Mexico, in Geological Survey Research 1969: U.S. 

Geological Survey Professional Paper 650-B, p. 149-153.

Purtymun, WD, Enyart, E. A., and McLin, S.G., 1989, Hydrologic characteristics of the Bandelier 

Tuff as determined through an injection well system: Los Alamos National Laboratory 

Report LA-11511-MS, 20 p.

Purtymun, WD, and Johansen, Steven, 1974, General geohydrology of the Pajarito Plateau, in 

Guidebook to Ghost Ranch (central-northern New Mexico): New Mexico Geological Society, 

25th Field Conference, p. 347-349.

Purtymun, WD, McLin, S.G., Stoker, A.K., Maes, M.N., and Hammock, B.C., 1993, Water Supply 

at Los Alamos during 1990: Los Alamos National Laboratory Progress Report LA-12471-PR, 

50 p.

Reiland, L.J., 1975, Estimated mean monthly and annual runoff at selected sites in the Pojoaque 

River drainage basin, Santa Fe County, New Mexico: U.S. Geological Survey Open-File 

Report 74-150,21 p.

Reiland, L.J., and Koopman, F.C., 1975, Estimated availability of surface and ground water in the 

Pojoaque River drainage basin, Santa Fe County, New Mexico: U.S. Geological Survey 

Open-File Report 74-151,35 p.

Sorensen, E.F., 1977, Water use by categories in New Mexico counties and river basins, and 

irrigated and dry cropland acreage in 1975: New Mexico State Engineer Technical Report 41, 

34 p.

Spiegel, Zane, and Baldwin, Brewster, 1963, Geology and water resources of the Santa Fe area, 

New Mexico: U.S. Geological Survey Water-Supply Paper 1525,258 p.

Stoker, A.K., McLin, S.G., Purtymun, WD., Maes, M.N., and Hammock, B.C., 1992, Water supply 

at Los Alamos during 1989: Los Alamos National Laboratory Progress Report LA-12276-PR, 

51 p.

Trauger, F.D., 1967, Hydrology and general geology of the Pojoaque area, Santa Fe County, New 

Mexico: U.S. Geological Survey Open-File Report, 32 p.

72
SUPPLEMENTAL INFORMATION

73
Table 5.~Constant-flow-boundary recharge rates, in cubic feet

per second 

[Recharge: negative value represents discharge]

Layer

Model

Row Column Recharge Layer

Sangre de Cristo Mountains

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1-6

17

18

19

20

21

22

23

24

25

26

27

28

29

31

Streambeds except

1

1

1

1

1

1

1

1

1

14

14

13

17

18

19

20

28

28

24

24

24

24

24

24

24

24

25

25

25

25

25

25

25

25

25

25

25

24

24

24

24

24

24

24

24

24

23

0.6

0.6

0.6

0.6

0.6

0.6

0.6

0.6

1.0

1.0

0.7

0.7

0.7

0.7

0.7

0.7

0.5

0.4

0,4

0.8

0.8

1.4

1.4

1.4

0.5

0.15

0.5

0.5

1.1

1

Santa Fe River'-

24

25

24

23

23

24

25

23

22

0.4

1.4

2.0

0.5

1.0

1.2

1.5

0.4

0.3

La Cienega Springs

1

1

1

1

1

30

31

31

32

32

13

15

14

13

12

-0.9

-1.4

-1.4

-1.4

-1.4

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

Model

Row Column Recharge

South boundary

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

33

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

0.027

0.0032

-0.00027

-0.0030

-0.041

-0.017

-0.021

-0.0073

-0.012

-0.011

-0.010

0.016

-0.0071

-0.019

-0.024

0.040

0.0047

0.00026

-0.0027

-0.033

-0.030

-0.037

-0.011

-0.017

-0.015

-0.014

0.022

-0.0073

-0.022

-0.025

-0.023

0.044

0.0057

0.00083

-0.0019

-0.036

-0.042

-0.048

-0.014

-0.019

-0.017

-0.016

0.026

-0.0084

-0.024

-0.024

-0.021

74
Table 5. Constant-flow-boundary recharge rates, in cubic feet

per second Concluded

Layer

Model

Row Column Recharge Layer

South boundary (concluded)

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

32

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

0

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

0

-0

-0

-0

0

0

0

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

0

.10

.0059

.0021

.027

.27

.21

.15

.054

.062

.046

.053

.054

.016

.0015

.050

.092

.091

.0081

.00066

.016

.19

.076

.074

.035

.037

.036

.054

.048

.063

.017

.0090

.096

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Model

Row Column

Pajarito Fault

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

6

6

5

4

4

3

3

2

2

1

1

1

1

1

2

2

2

2

2

Recharge

Zone

0

0

0

0

0

0

0

0

0

0

0

0

1

1

1

0

0

0

0

.20

.25

.35

.24

.23

.35

.23

.34

.53

.72

.67

.80

.5

.7

.1

.39

.19

.21

.18

Flow rates for Santa Fe River, variable, are reported elsewhere.

75
Table 6. Specified discharge from Los Alamos wells, in cubic feet

per second 

[Well locations shown in figure 2]

Stress Well name

period and 

year LA- IB

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

1947

1948

1949

1950

1951

1952

1953

1954

1955

1956

1957

1958

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

0

0

0

0

0

0

0

0

0

0

0

0

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.154

.530

.548

.498

.552

.416

.356

.360

.314

.322

.338

.378

.320

.370

.314

.316

.338

.358

.320

.196

.268

.314

.458

.051

.410

.290

.233

LA-1

-0

~0

-0

-0

-0

-0

0

0

-0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

.229

.147

.113

.045

.062

.014

.0

.0

.041

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

LA- 2

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

.117

.251

.177

.066

.245

.196

.200

.241

.209

.187

.125

.132

.173

.219

.188

.151

.173

.145

.169

.091

.021

.048

.016

.031

.135

.167

.198

.156

.170

.169

.180

.167

.111

.143

.146

.217

.231

.227

.157

.102

LA- 3

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

.275

.350

.177

.245

.284

.248

.295

.243

.206

.178

.111

.142

.148

.163

.147

.192

.180

.214

.184

.195

.201

.181

.170

.187

.192

.168

.086

.184

.184

.179

.201

.180

.119

.149

.176

.233

.062

.070

.177

.114

LA- 4

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

0

-0

-0

-0

-0

.0

.182

.160

.700

.736

.508

.462

.332

.402

.510

.448

.468

.482

.618

.550

.548

.554

.658

.472

.490

.328

.346

.262

.354

.378

.350

.392

.348

.350

.416

.410

.340

.444

.490

.380

.0

.261

.369

.366

.164

LA- 5

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

.0

.172

.248

.552

.794

.466

.440

.340

.412

.444

.366

.382

.396

.506

.426

.458

.446

.504

.214

.336

.312

.268

.290

.280

.316

.274

.290

.224

.272

.330

.318

.276

.356

.392

.410

.434

.331

.305

.236

.147

LA- 6

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

0

-0

-0

0

0

0

0

0

0

0

.0

.022

.406

.712

.856

.468

.482

.454

.458

.534

.434

.454

.460

.588

.478

.550

.436

.586

.440

.442

.362

.304

.346

.336

.350

.336

.384

.338

.220

.022

.0

.006

.002

.0

.0

.0

.0

.0

.0

.0

Sum

-0.621

-1.124

-1.281

-2.320

-2.977

-1.900

-1.879

-1.610

-1.728

-1.853

-1.484

-1.578

-1.659

-2.248

-2.319

-2.447

-2.287

-2.659

-1.895

-1.910

-1.584

-1.461

-1.406

-1.526

-1.749

-1.615

-1.720

-1.564

-1.512

-1.454

-1.467

-1.289

-1.228

-1.442

-1.426

-1.342

-0.936

-1.381

-1.226

-0.760

76
Table 6. Specified discharge from Los Alamos wells, in cubic feet

per second Concluded

Stress 

period and 

year

41 1987

42 1988

43 1989

44 1990

45 1991

46 1992

47 1993-2013

Well name

LA- IB

-0

-0

-0

-0

-0

0

0

.412

.319

.414

.291

.213

.0

.0

LA-1

0

0

0

0

0

0

0

.0

.0

.0

.0

.0

.0

.0

LA- 2

-0

-0

-0

-0

-0

-0

0

.168

.140

.183

.171

.139

.057

.0

LA- 3

-0

-0

-0

-0

-0

0

0

.216

.170

.220

.189

.099

.0

.0

LA- 4

-0

0

0

0

0

0

0

.007

.0

.0

.0

.0

.0

.0

LA-5

-0

-0

-0

-0

-0

0

0

.118

.042

.112

.141

.078

.0

.0

LA-6

0.0

0.0

0.0

0.0

0.0

0.0

0.0

Sum

-0

-0

-0

-0

-0

-0

0

.921

.671

.929

.792

.529

.057

.0

77
Table /.-Specified discharge from Guaje wells, in cubic feet per second 

[Well locations shown in figure 2]

00

Stress 

period anc 

year

i

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

1947

1948

1949

1950

1951

1952

1953

1954

1955

1956

1957

1958

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

Well name

1 G-l

0.

0.

0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

0

0

0

012

160

320

412

330

300

354

238

290

350

408

476

398

488

482

384

436

296

334

290

274

288

280

286

264

236

276

G-1A

0

0

0

0

0

0

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

.0

.0

.0

.0

.0

.0

.0

.020

.226

.458

.370

.392

.436

.522

.624

.578

.636

.548

.494

.566

.388

.438

.384

.392

.474

.398

.374

.394

.362

.388

G-2

0

0

0

0

-0

-0

-0

-0

-0

-0

-0

-0

-.0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

.0

.0

.0

.0

.018

.332

.448

.366

.334

.406

.324

.340

.360

.410

.446

.424

.448

.446

.350

.402

.288

.282

.292

.266

.370

.312

.308

.348

.316

.344

G-3

0

0

0

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

.0

.0

.0

.0

.032

.278

.324

.280

.294

.374

.298

.296

.316

.350

.340

.356

.368

.334

.278

.312

.224

.240

.216

.236

.272

.216

.202

.210

.184

.350

G-4

0

0

0

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

.0

.0

.0

.0

.054

.242

.234

.250

.096

.144

.104

.152

.134

.158

.192

.178

.198

.182

.102

.142

.190

.134

.074

.034

.090

.142

.158

.146

.174

.246

G-5

0.0

0.0

0.0

0.0

-0.028

-0.314

-0.160

-0.344

-0.342

-0.412

-0.272

-0.208

-0.432

-0.416

-0.568

-0.602

-0.640

-0.638

-0.496

-0.354

-0.340

-0.344

-0.354

-0.378

-0.374

-0.392

-0.414

-0.292

-0.318

-0.404

G-6

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.192

.318

.392

.246

.238

.236

.216

.182

.242

.278

.270

.240

.246

GR-2

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

GR-3

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

G

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0
Table 7. Specified discharge from Guaje wells, in cubic feet per second C

s

per

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

X 47

*47

tress 

iod and 

year

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993-2013

1993-2013

Well name

G-l

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

0.

0.

.246

.238

.262

.290

.346

.292

.221

.266

.205

.128

.124

.023

,114

.130

.089

,051

,0

,0

G-1A

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

0

0

.376

.330

.374

.438

.556

.466

.367

.482

.544

.552

.519

.566

.557

.616

.636

.568

.0

.0

G-2

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

0

0

.342

.304

.340

.392

.162

.110

.070

.185

.409

.463

.465

.563

.567

.570

.522

.546

.0

.0

G-3

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

0

-0

0

0

0

0

0

0

.334

.282

.292

.262

.282

.216

.133

.080

.094

.113

.0

.014

.0

.0

.0

.0

.0

.0

G-4

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

0.

0.

266

210

224

152

036

276

179

211

092

144

106

017

091

071

058

051

0

0

G-5

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

0.0

0.0

390

358

368

378

284

162

310

489

288

222

494

488

470

505

479

485

G-6

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

0.

0.

232

164

078

146

324

270

150

234

302

325

345

348

346

360

344

298

0

0

GR-2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

-0

0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.397

.0

GR-3

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

-0

0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.397

.0

G

-

1 Two projections: first is with Guaje field producing, second is without Guaje field producing.
Table 8.~Specified discharge from Pajarito Mesa and Otowi wells,

in cubic feet per second 

[Well locations shown in figure 2]

Stress period and

i

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

461 47

X 47

year

1947

1948

1949

1950

1951

1952

1953

1954

1955

1956

1957

1958

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993-2013

1993-2013

PM-1

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

D.O

0.0

0.0

0.0

0.0

0.0

0.0

-0.422

-0.458

-0.472

-0.290

-0.146

-0.282

-0.428

-0.360

-0.198

-0.408

-0.402

-0.454

-0.448

-0.384

-0.354

-0.418

-0.418

-0.422

-0.366

-0.393

-0.404

-0.313

-0.434

-0.415

-0.444

-0.374

-0.375

-0.393

-0.282

-0.378

PM-1

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

-0.

-1.

-1.

-1.

-1.

-1.

-1.

-1.

-1.

-1.

-1.

-1.

-1.

-1.

-1.

-1.

-1.

-0.

-0.

-0.

-0.

-0.

-0.

-0.

-1.

-0.

-1.

-0.

-1.

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

080

568

392

186

274

440

634

614

912

634

874

156

646

618

736

570

524

669

346

607

358

120

622

551

061

723

176

844

131

PM-3

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.794

-1.080

-0.966

-0.918

-0.814

-1.094

-1.082

-1.142

-1.138

-0.998

-0.894

-0.836

-0.994

-0.986

-1.010

-0.879

-1.167

-0.937

-1.037

-1.060

-0.983

-0.936

-1.036

-0.972

-1.302

-0.935

-1.253

Well name

PM-4

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-1.917

-1.380

-1.606

-1.302

-1.661

-0.926

-1.774

-0.929

-0.930

-0.671

-0.482

-0.646

PM-5

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.0

.008

.624

.502

.545

.365

.513

.475

.883

.634

.850

O-l

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.397

-0.699

O-4

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-1.191

-1.398

Sum

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.422

-0.538

-2.040

-2.476

-2.412

-2.522

-2.786

-2.808

-2.906

-3.402

-3.178

-3.466

-2.602

-2.924

-2.808

-3.148

-2.974

-2.956

-3.831

-3.286

-3.562

-3.634

-3.777

-3.491

-4.070

-3.913

-3.475

-4.425

-4.765

-6.355

1 Two projections: 

producing.

first is with Guaje field producing, second is without Guaje field

80
Table 9. Specified discharge from Buckman wells, in cubic feet per second

[Well locations shown in figure 2]

pe

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

Stress 

riod and 

year

1947

1948

1949

1950

1951

1952

1953

1954

1955

1956

1957

1958

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993-2013

Well name

B-l

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.007

-0.128

-0.575

-0.777

-0.720

-0.436

-0.657

-0.392

-0.222

-0.104

-0.104

B-2

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.008

-0.270

-0.841

-1.219

-1.127

-0.974

-1.487

-0.980

-0.611

-0.471

-0.471

B-3

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.392

-1.080

-1.430

-0.914

-1.232

-1.382

-0.742

-0.236

-0.234

-1.182

-0.574

-0.002

0.0

0.0

0.0

0.0

-0.203

-0.308

-0.307

-0.207

-0.083

-0.083

B-4

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.390

-1.010

-1.296

-1.010

-1.326

-1.452

-0.742

-0.236

-0.234

-1.180

-0.574

0.0

0.0

0.0

0.0

0.0

-0.707

-1.220

-1.204

-0.734

-0.299

-0.299

B-5

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.256

-0.106

-0.002

0.0

0.0

-0.236

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.102

-0.173

-0.169

-0.112

-0.019

-0.019

B-6

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.392

-1.038

-1.564

-1.250

-1.176

-1.240

-0.740

0.0

-0.234

-1.182

-0.574

0.0

0.0

0.0

0.0

0.0

-0.940

-1.463

-1.387

-0.914

-0.887

-0.887

B-7

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.349

-0.728

-0.728

B-8

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.439

-0.734

-0.734

Sum

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-1.174

-3.128

-4.546

-3.280

-3.736

-4.074

-2.224

-0.708

-0.702

-3.544

-1.722

-0.017

-0.398

-1.416

-1.996

-1.847

-3.362

-5.308

-4.439

-3.588

-3.325

-3.325

81
Table 10.~Specified discharge from Santa Fe wells, in cubic feet per secon

[Well locations shown in figure 2]

00

to

Well name

Stress period 

and year Alto1

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

1947

1948

1949

1950

1951

1952

1953

1954

1955

1956

1957

1958

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

0.0

0.0

0.0

-0.127

-1.697

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.008

0.0

-0.012

0.0

-0.008

-0.012

0.0

-0.004

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

Alto 2

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.424

-0.385

-0.787

-0.638

-0.135

-0.219

-0.001

-0.166

FerFerguson1 guson 2

0.0

0.0

0.0

0.0

-0.275

3 -0.235

3 -0.202

3 -0.557

3 -0.641

3 -0.975

3-0.380

0.0

-0.029

-0.047

-0.008

-0.047

-0.008

-0.021

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.386

-0.655

-0.431

-0.135

-0.168

-0.001

-0.102

Torreon

0.0

0.0

0.0

0.0

-0.654

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.015

-0.051

-0.028

-0.051

-0.106

0.0

0.0

-0.161

-0.301

-0.032

-0.702

-0.840

-0.551

0.0

-0.120

0.0

-0.018

Agua 

Santa Fe Fria

0.0

0.0

0.0

0.0

-0.366

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.631

-0.254

-0.233

-0.021

-0.203

-0.876

-0.091

-0.076

-1.101

-0.322

-0.262

-0.962

-0.896

-0.676

-0.305

-0.744

-0.177

-0.693

0.0

0.0

0.0

0.0

0.0

3 -0.235

3 -0.202

3 -0.557

3 -0.641

3 -0.975

3 -0.380

0.0

-0.999

-0.428

-0.326

-0.352

-0.614

-1.922

-0.174

-0.102

-1.859

-0.872

-1.134

-1.562

-1.638

-1.323

-0.642

-0.944

-0.403

-0.832

St. 

Micheal' s

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.047

-0.360

-0.170

-1.368

0.0

-0.055

-1.155

-0.174

0.0

-0.931

-1.097

-0.767

-0.098

-0.843

-0.040

-0.667

Os

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0
Table 10.--Specified discharge from Santa Fe wells, in cubic feet per second 

oo

Well name

Stress period 

and year

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993-2013

Alto1

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

Alto 2

-0.152

3 -0.062

3 -0.132

3 -0.186

3 -0.237

3 -0.237

-0.487

-0.615

-0.471

-0.373

-0.482

-0.619

-0.717

-0.569

-0.552

-0.432

-0.432

FerFerguson1 guson 2

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.163

3 -0.052

3 -0.113

3 -0.157

3 -0.201

3 -0.201

-0.076

-0.291

-0.495

-0.537

-0.599

-0.469

-0.530

-0.422

-0.383

-0.403

-0.403

Torreon

0.0

3 -0.012

3 -0.028

3 -0.039

3 -0.050

3 -0.050

-0.581

-0.209

0.0

0.0

0.0

-0.025

-0.043

0.0

0.0

0.0

0.0

Agua 

Santa Fe Fria

-0.277

3 -0.204

3 -0.432

3-0.604

3 -0.771

3 -0.771

-0.767

-0.770

-0.558

-0.672

-0.657

-0.417

-0.113

-0.451

-0.418

-0.092

-0.092

-1.391

3 -0.393

3 -0.834

3 -1.166

3 -1.488

3 -1.488

-1.921

-1.811

-1.358

-1.016

-2.083

-1.822

-2.161

-2.089

-1.858

-1.927

-1.927

St. 

Micheal's Osag

-0.791

-0.391

-0.121

0.0

-0.839

-0.258

0.0

0.0

0.0

0.0

-0.104

-0.629

-0.720

-0.335

-0.089

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

-0.03

-0.03

-0.034

-0.03

-0.03

and Ferguson apparently were replaced or deepened in 1969 and 1970. 

2 Pumpage from Alto, Torreon,and Santa Fe wells was combined for 1952-57. 

3Estimated from total pumpage.
Table 11. Percentage of public-supply well pumpage assigned to each model layer

[Well locations shown in figure 2]

Percent in model layer2

Row

10

10

10

1011

11

10

9

9

8

8

8

8

8

8

8

8

8

11

11

12

13

11

12

12

13

14

14

14

14

14

14

13

25

24

24

24

24

23

23

24

24

24

Column Well name

11

11

11

11

9

10

10

9

9

9

8

7

7

6

9

8

7

7

9

5

7

5

6

5

4

11

11

11

11

12

12

12

11

22

22

22

21

22

22

22

22

21

22

LA- IB

LA-1

LA-2

LA-3

LA-4

LA-5

LA- 6

G-l

G-1A

G-2

G-3

G-4

G-5

G-6

GR-2

GR-3

GR-4

GR-1

0-1

0-4

PM-1

PM-2

PM-3

PM-4

PM-5

Buckman- 1

Buckman-2

Buckman- 3

Buckman -4

Buckman- 5

Buckman- 6

Buckman-7

Buckman- 8

St. Micheal's

Alto

Alto 2

Osage

Torreon

Ferguson

Ferguson 2

Santa Fe

Agua Fria

A, T, & SF1

1

0

17

12

12

0

0

0

0

14

10

2

8

10

0

10

10

10

10

0

0

0

1

0

0

0

0

0

0

0

0

0

0

0

23

72

8

27

35

45

14

14

28

26

.4

.5

.5

.7

.6

.9

.07

.9

.9

.9

.9

.9

.47

.5

.2

.5

.2.

.5

.8

.9

.3

2

10

34

36

36

0

8

4

14

22

16

20

18

20

31

20

20

20

20

9

10

16

21

16

17

14

25

17

23

1

24

20

4

18

45

27

55

37

48

54

48

19

39

27

.9

.2

.2

.2

.15

.42

.4

.2

.4

.5

.3

.1

.7

.1

.1

.1

.1

.11

.3

.3

.3

.3

.3

.9

.7

.7

.2

.98

.1

.8

.03

.3

.8

.8

.7

.5

.8

.2

.2

.3

.7

.7

3

23

40

42

42

11

25

23

21

26

19

24

21

23

46

23

23

23

23

22

22

21

25

20

20

19

39

24

28

42

34

37

65

62

30

0

35

35

15

0

37

22

31

18

.8

.4

.8

.8

.2

.9

.8

.2

.4

.2

.7

.8

.4

.8

.8

.8

.8

.3

.3

.2

.4

.4

.9

.7

.5

.2

.8

.9

.9

.5

.5

.7

.8

.3

.6

.8

.8

.5

.3

4

34

8

8

8

39

36

35

31

36

28

35

31

34

21

34

34

34

34

32

32

30

36

29

29

29

34

35

41

55

41

41

30

19

0

0

0

0

0

0

0

33

0

21

.7

.07

.55

.55

.3

.5

.9

.9

.3

.3

.7

.7

.9

.7

.7

.7

.7

.5

.6

.7

.8

.9

.8

.1

.6

.9

.2

.2

.3

.4

.2

.3

5

30.6

0

0

0

49.5

30.3

36.7

31.9

0

25.4

17.1

20.2

10.5

0

10.5

10.5

10.5

10.5

36.1

34.9

32.1

15.3

33.4

32.6

36.1

0

21.9

7.4

0

0

0

0

0

0

0

0

0

0

0

0

10.6

0

6.68

1 Alto, Torreon, and Santa Fe wells, when these wells were combined. 

2 Total percent does not equal 100 due to rounding.

84
Table 12.--Specified discharge from domestic and industrial wells,

in cubic feet per second

Stress 

period

i

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Year

1947

1948

1949

1950

1951

1952

1953

1954

1955

1956

1957

1958

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

Specified 

discharge

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

-0

_ 1

_ -1

_ -^

_ -^

-1

_ -^

-1

.174

.252

.258

.264

.292

.310

.317

.317

.590

.590

.625

.625

.625

.625

.625

.625

.635

.635

.032

.032

.041

.041

.041

.041

.041

Stress 

period

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

Year

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993-2013

Specified 

discharge

-1.053

-1.053

-1.129

-1.129

-1.144

-1.144

-1.144

-1.144

-1.144

-1.144

-1.144

-1.179

-1.215

-1.250

-1.286

-1.322

-1.357

-1.392

-1.428

-1.463

-1.499

-1.499

85
Table 13. Difference between measured and model-derived 

hydraulic heads, in feet

Model

Row

5

6

6

6

7

7

7

8

8

8

9

9

9

9

9

9

9

9

9

10

10

10

10

10

10

10

10

10

10

10

10

11

11

11

11

11

11

11

11

12

12

12

13

13

14

Column

19

15

18

19

15

19

22

19

21

23

15

16

19

20

20

20

21

21

22

3

5

14

15

16

18

19

19

19

20

22

25

4

5

8

18

19

20

20

23

20

20

24

19

25

4

Hydraulic head

Local well name 

or number

Steady state,

20.09.18.4421

20.08.34.144

20.09.30.31233

20.09.19.4244

20.08.34.14423

20.09.32.310

20.09.34.411

19.09.05.131

19.09.03.311

20.09.36.344

19.08.10.324

19.08.11.144

19.09.08.133

19.09.08.233

19.09.08.224

19.09.09.1444

19.09.03.341

19.09.10.122

19.09.10.224

TW-4

TW-2

19.08.16.131

19.08.15.411

19.08.14.144

19.08.12.433

19.09.07.424

19.09.17.123

19.09.17.142

19.09.17.210

19.09.15.412

19.10.18.231

TW-8

TW-3

TW-1

19.08.13.431

19.09.20.124

19.09.20.223

19.09.20.244

19.09.14.441

19.09.29.214

19.09.28.143

19.09.25.432

19.09.29.331

19.10.29.341

DT-10

Model 

Measured derived

model

5, 752.

5,559.

5,830.

5,743.

5,549.

5,834.

6,038.

5,832.

6,005.

6,299.

5,625.

5, 680.

5,835.

5,887.

5,890.

5,928.

6,024.

6,030.

6,043.

6,073.

5,889.

5, 683.

5, 666.

5,697.

5,740.

5,826.

5,849.

5,871.

5,884.

5, 989.

6, 623.

5, 908.

5,952.

5,784.

5,833.

5, 944.

5, 967.

5, 989.

6,147.

5,991.

6,052.

6,295.

6,096.

6,795.

5,928.

layer 1

5,845.3

5,642.3

5,807.7

5,861.2

5,660.1

5,873.5

6,053.7

5,877.8

6,001.5

6,148.2

5,615.3

5,675.1

5,854.9

5,925.6

5,925.6

5,925.6

5,989.0

5, 989.0

6,092.9

59 6,059.9

16 5,905.2

5,749.9

5,762.8

5,782.9

5,858.1

5,883.4

5,883.4

5,883.4

5,980.1

6,109.6

6,574.2

90 5,940.1

01 5,903.3

29 5,838.6

5,899.6

5,918.5

6,020.3

6,020.3

6,229.8

6,049.0

6,049.0

6,471.3

6,042.5

6,751.3

35 5,935.7

Difference

(model 

derived 

minus 

measured)

93.3

83.3

-22.3

118.2

111.1

39.5

15.7

45.8

-3.5

-150.8

-9.7

-4.9

19. 9

38.6

35.6

-2.4

-35.0

-41.0

49.9

-13.7

16.0

66.9

96.8

85.9

118.1

57.4

34.4

12.4

96.1

120.6

-48.8

31.2

-48.7

54.3

66.6

-25.5

53.3

31.3

82.8

58.0

-3.0

176.3

-53.5

-43.7

7.4

86
Table 13.~Difference between measured and model-derived 

hydraulic heads, in feet Continued

Model

Row

14

14

14

14

14

14

14

14

15

15

15

16

16

16

16

16

17

18

18

18

18

19

19

19

19

19

19

19

20

20

20

20

20

20

20

20

21

21

22

23

23

23

23

23

23

24

24

24

24

24

Column

14

21

21

22

24

24

25

25

4

15

22

14

24

24

24

24

23

17

23

23

25

12

14

14

20

22

23

24

13

17

17

19

21

23

25

25

23

24

22

22

22

23

23

23

24

14

20

21

21

21

Hydraulic head

Local well name 

or number

19.08.32.443

18.09.03.112

18.09.03.142

18.09.02.133

18.10.06.112

18.10.06.111

18.10.06.243

18.10.06.244

DT-9

18.08.10.143

18.09.10.224

18.08.17.223

18.10.07.342

18.10.07.342

18.10.18.131

18.10.18.132

18.09.24.111

18.08.24.300

18.09.25.113

18.09.25.13111

18.10.30.421

18.07.36.422

18.08.33.143

18.08.33.143

18.09.33.233

18.09.27.431

18.09.25.433

18.10.31.413

17.08.05.323

17.08.01.212

17.08.01.212

17.09.06.223

17.09.03.124

17.09.01.121

17.10.06.242

17.10.05.112

17.09.01.334

17.09.12.222

17.09.15.2432

17.09.23.133

17.09.23.322

17.09.24.114

17.09.24.124A

17.09.24.324

17.10.18.333

17.08.21.414

17.09.28.321

17.09.22.343

17.09.27.143

17.09.27.144

Measured

5,766.

6,235.

6,262.

6,391.

6,701.

6,702.

6,812.

6,840.

5, 933.71

5,850.

6,340.

5,825.

6, 688.

6, 688.

6,724.

6,725.

6,564.

6,105.

6, 652.

6,653.

6,808.

5,720.

5,800.

5,836.

6,339.

6, 639.

6,760.

6, 904.

5,843.

6,145.

6,149.

6,220.

6, 699.

6,875.

7,012.

7, 059.

6,730.

6,850.

6,768.

6,807.

6,823.

6, 916.

6, 949.

6, 970.

6, 939.

6,139.

6,570.

6,726.

6,749.

6,752.

Model 

derived

5,849.7

6,216.8

6,216.8

6,328.9

6,649.8

6, 649.8

6,876.8

6,876.8

5, 933.5

5,886.4

6,368.8

5,877.2

6, 629.5

6,629.5

6,629.5

6,629.5

6,611.7

6,074.5

6,690.1

6, 690.1

6,850.4

5,852.0

5,907.2

5, 907.2

6,352.8

6,551.6

6,679.5

6,849.2

5,891.2

6,144.6

6,144.6

6,298.8

6,479.3

6,696.0

7,055.7

7,055.7

6,727.0

6,868.8

6, 666.5

6,756.2

6,756.2

6,881.3

6,881.3

6,881.3

7,047.0

6,135.5

6,525.0

6,698.1

6,698.1

6, 6.98.1

Difference 

(model 

derived

minus 

measured)

83.7

-18.2

-45.2

-62.1

-51.2

-52.2

64.8

36.8

-0.2

36.4

28.8

52.2

-58.5

-58.5

-94.5

-95.5

47.7

-30.5

38.1

37.1

42.4

132.0

'107.2

71.2

13.8

-87.4

-80.5

-54.8

48.2

-0.4

-4.4

78.8

-219.7

-179.0

43.7

-3.3

-3.0

18.8

-101.5

-50.8

-66.8

-34.7

-67.7

-88.7

108.0

-3.5

-45.0

-27.9

-50.9

-53.9

87
Table 13.--Difference between measured and model-derived 

hydraulic heads, in feet Continued

Hydraulic head

ffl^r-J^T

Row

24

24

24

24

24

24

24

24

24

24

24

24

25

25

25

25

25

25

25

25

26

26

26

26

26

26

26

26

26

26

26

27

27

27

27

27

27

27

27

27

27

27

27

27

27

28

28

28

28

28

J\JX5J.

Column

21

22

22

22

23

23

23

24

24

24

24

24

18

19

21

22

23

24

24

24

14

15

19

20

21

21

22

22

22

23

23

14

16

17

17

19

19

20

21

21

22

22

22

23

23

13

15

17

18

18

Local well name

or number

17.09.27.232

17.09.27.241

17.09.23.333

17.09.23.332

17.09.26.222

17.09.24.343

17.09.25.324

17.09.24.432

17.10.19.331

17.09.25.421

17.10.30.131

17.10.30.123

17.09.30.433

17.09.32.111

17.09.33.421

17.09.27.441

17.09.25.343'

17.09.36.243

17.09.36.422

17.10.31.134

16.08.04.132

17.08.34.342

17.09.31.44221

17.09.33.211A

16.09.03.312

16.09.03.134

16.09.02.31212

16.09.02.121

17.09.34.422

16.09.01.11344

17.09.36.323

16.08.09.421

16.08.10.422

16.08.01.34223

16.08.12.322

16.09.05.334

16.09.05.331

16.09.09.321

16.09.09.221

16.09.03.421

16.09.10.242

16.09.10.42114

16.09.02.33241

16.09.02.441

16.09.01.31121

16.08.17.2122

16.08.15.143

16.08.12.332

16.08.13.243

16.08.13.243

Measured

6,764.

6,744.

6,786.

6,799.

6,917.

6,971.

6, 991.

6,998.

7,025.

7,058.

7,078.

7,085.

6,163.

6,285.

6,560.

6,746.

6,990.

7,023.

7,028.

7,089.

6,133.

6,177.

6,308.

6,552.

6,538.

6,562.

6,692.

6,710.

6,727.

6,796.

6,868.

6,122.

6,157.

6,171.

6,175.

6,337.

6,338.

6,513.

6,531.

6,679.

6,657.

6,670.

6,681.

6,758.

6,792.

6,158.

6,167.

6,156.

6,163.

6,163.

Model

derived

6,698.1

6,786.9

6,786.9

6,786.9

6,926.2

6,926.2

6,926.2

7,164.7

7,164.7

7,164.7

7,164.7

7,164.7

6,250.1

6,547.7

6,632.6

6,725.5

6,869.9

7,177.6

7,177.6

7,177.6

6,160.9

6,177.2

6,352.5

6,492.1

6,589.9

6,589.9

6,684.2

6,684.2

6,684.2

6,791.0

6,791.0

6,161.3

6,199.4

6,224.0

6,224.0

6,327.0

6,327.0

6,453.0

6,558.0

6,558.0

6,656.6

6,656.6

6, 656.6

6,744.1

6,744.1

6,139.8

6,169.4

6,207.3

6,225.0

6,225.0

Difference 

(model 

derived

minus

measured)

-65.9

42.9

0.9

-12.1

9.2

-44.8

-64.8

166.7

139.7

106.7

86.7

79.7

87.1

262.7

72.6

-20.5

-120.1

154.6

149.6

88.6

27.9

0.2

44.5

-59.9

51.9

27.9

-7.8

-25.8

-42.8

-5.0

-77.0

39.3

42.4

53.0

49.0

-10.0

-11.0

-60.0

27.0

-121.0

-0.4

-13.4

-24.4

-13.9

-47.9

-18.2

2.4

51.3

62.0

62.0

88
Table 13.~Difference between measured and model-derived 

hydraulic heads, in feet Continued

Model

Row

28

28

28

29

29

29

29

29

29

29

29

30

30

30

30

31

31

32

32

33

33

33

10

14

8

8

8

8

9

10

10

10

8

9

11

11

11

12

13

2

2

2

3

3

Column

21

22

22

17

17

17

18

18

19

22

23

16

17

20

20

16

18

9

17

13

16

21

11

3

7

7

7

9

9

10

11

11

8

9

6

9

10

7

5

20

21

24

17

19

Hydraulic head

Local well name 

or number

16.09.16.243

16.09.15.223

16.09.15.242

16.08.13.323

16.08.24.144

16.08.14.444

16.08.24.421

16.08.13.444

16.09.19.221

16.09.23.311

16.09.24.112

16.08.23.434

16.08.24.333

16.09.29.241

16.09.28.113

16.08.35.111

16.08.25.424

16.07.33.444

15.08.01.321

15.08.07.242

15.08.10.244

15.09.09.222

Steady state,

LA-1

DT-5A

Steady state,

G-6

G-4

G-5

G-2

G-1A

LA- 6

LA- 3

LA- 2

Steady state,

G-3

G-l

PM-3

LA- 4

LA- 5

PM-1

PM-2

Transient, 1977

20.09.05.2443

20.09.04.2234

20.09.01.2223

20.08.12.23412

20.09.06.4422

Model 

Measured derived

6,485.

6,632.

6,784.

6,164.

6,165.

6,167.

6,122.

6,218.

6,207.

6,578.

6,702.

6,139.

6,146.

6,330.

6,363.

6,130.

6,179.

5,580.

6,160.

5,999.

6,144.

6,370.

model

5, 605.

5,970.

model

5,841.

5,871.

5,892.

5,795.

5,749.

5,687.

5,575.

5,592.

model

5,858.

5,778.

5,897.

5,697.

5,709.

5,774.

5,889.

6,528.0

6,672.8

6,672.8

6,195.8

6,195.8

6,195.8

6,212.2

6,212.2

6,267.1

6,585.9

6,679.7

6,167.5

6,188.2

6,326.9

6,326.9

6,157.3

6,200.6

5,614.4

6,177.0

6,002.7

6,138.2

6,379.2

layer 2

5,686.2

84 5,973.1

layer 3

5,874.2

5,874.2

5,874.2

5,804.7

5,804.6

5,761.9

5,719.7

5,719.7

layer 4

5,839.4

5,806.9

5,893.4

5,794.8

5,761.5

5,873.9

5,905.3

Difference 

(model 

derived 

minus 

measured)

43.0

40.8

-111.2

31.8

30.8

28.8

90.2

-5.8

60.1

7.9

-22.3

28.5

42.2

-3.1

-36.1

27.3

21.6

34.4

17.0

3.7

-5.8

9.2

81.2

2.3

33.2

3.2

-17. a

9.7

55.6

74.9

144.7

127.7

-18.6

28.9

-3.6

97.8

52.5

99.9

16.3

, model layer 1

5,794.

5,828.

6,127.

5,671.

5,745.

33 5,851.8

06 5,920.9

86 6,185.4

5,681.6

21 5,808.4

57.5

92.8

57.5

10.6

63.2

89
Table 13. Difference between measured and model-derived 

hydraulic heads, in feet Continued

Hydraulic head

Model

Row

3

3

3

3

4

5

5

7

8

9

9

9

9

9

9

9

10

10

12

13

14

15

16

17

18

18

19

19

20

20

25

25

25

25

26

26

26

26

26

26

26

27

27

28

29

29

30

33

Column

19

20

24

24

18

19

19

19

18

13

14

18

18

19

19

20

5

17

20

21

25

4

24

24

23

23

19

23

18

22

21

21

21

24

20

20

20

21

22

22

23

17

22

14

17

18

16

23

Local well name

or number

20.09.05.3224

20.09.09.1124

20.10.07.1111

20.09.01.4444

20.09.18.11114

20.09.19.22311

20.09.18.4212

20.09.30.4241

19.09.06.2311

19.08.06.4224

19.08.08.42121

19.08.12.4323

19.09.06.4133

19.09.05.3232

19.09.08.1224

19.09.09.1444

TW-2

19.09.07.1414

19.09.21.34343

19.09.28.4241

18.10.06.24314

DT-9

18.10.18.13112

18.09.24.2424

18.09.25.13111

18.09.24.4341

18.09.31.42424

18.09.35.2214

17.09.06.14432

17.09.02.211

17.09.28.441

17.09.27.31344

17.09.28.423B

17.10.31.134

17.09.33.43212

16.09.04.11222

17.09.32.44321

16.09.03.1213B

16.09.02.121

16.09.02.31212

16.09.01.31121

16.08.12.13114

16.09.10.42114

16.08.17.2122

16.08.14.444

16.08.13.444

16.08.26.32112

15.09.01.3314

Measured

5,752.89

5,819.89

6,119.55

6,122.72

5,671.00

5,773.92

5,777.78

5,769.00

5,842.58

5,514.48

5,556.70

5,739.90

5,829.85

5,855.15

5,874.74

5,928.96

5,872.56

5,794.00

6,011.53

6,140.00

6,819.01

5,930.90

6,724.04

6,733.40

6,642.01

6,679.71

6,229.90

6,710.38

6,213.59

6,692.00

6,696.08

6,696.69

6,707.

7,088.28

6,508.55

6,512.72

6,520.26

6,696.61

6, 645.14

6,646.15

6,790.73

6,173.63

6,603.

6,148.95

6,151.63

6,137.13

6,158.38

6,533.78

Model

derived

5,808.4

5,869.7

6,180.6

6,180.6

5,768.6

5,845.1

5,845.1

5,873.3

5,821.4

5,512.7

5,587.7

5,788.0

5,788.0

5,854.8

5,854.8

5,925.5

5,891.4

5,815.8

6,048.9

6,192.1

6,876.4

5,928.9

6, 629.2

6,674.0

6,689.2

6,689.2

6,267.0

6,678.3

6,218.9

6,580.3

6,596.4

6,596.4

6,596.4

7,172.4

6,477.0

6,477.0

6,477.0

6,576.5

6,671.4

6,671.4

6,783.0

6,238.6

6,653.0

6,168.6

6,198.2

6,214.5

6,169.1

6,552.9

Difference 

(model

derived

minus

measured)

55.5

49.8

61.1

57.9

97.6

71.2

67.3

104.3

-21.2

-1.8

31.0

48.1

-41.8

-0.4

-19.9

-3.5

18.8

21.8

37.4

52.1

57.4

-2.0

-94.8

-59.4

47.2

9.5

37.1

-32.1

5.3

-111.7

-99.7

-100.3

-110.6

84.1

-31.6

-35.7

-43.3

-120.1

26.3

25.2

-7.7

65.0

50.0

19.6

46.6

77.4

10.7

19.1

90
Table 13.~Di£ference between measured and model-derived 

hydraulic heads, in feet-Continued

Model

Hydraulic head

ijocax we-Li name

Row

2

2

3

3

3

3

3

4

5

5

6

8

8

8

9

9

9

9

9

9

9

9

9

10

10

10

10

10

10

11

11

11

12

14

15

15

15

16

16

17

18

19

24

24

25

Column

21

23

17

18

19

19

24

18

19

24

19

18

19

21

14

14

15

18

19

19

20

21

21

3

5

12

16

17

21

4

5

8

20

4

4

22

25

24

24

24

23

23

23

24

 19

or number

Transient, 1

20. 09 ,04.2234

20. 09.02.2122

20.08.12.23412

20.09.07.1414

20.09.06.4422

20.09.05.3224

20.09.01.4444

20.09.18.32221

20.09.18.4243

20.09.24.24343

20.09.19.4244

19.09.06.2333

20.09.32.31233

19.09.04.2212

19.08.08.42121

19.08.09.2114

19.08.10.12322

19.09.07.1414

19.09.08.2131

19.09.05.4113

19.09.09.1444

19.09.09.2423

19.09.10.4112

TW-4

TW-2

19.08.18.2311

19.08.11.3341

19.08.12.3421

19.09.10.3233

TW-8

TW-3

TW-1

19.09.21.34343

DT-10

DT-9

18.09.10.24211

18.10.08.2133

18.10.07.342

18.10.18.13112

18.09.24.2424

18.09.25.13111

18.09.35.2214

17. 09.24.343

17.10.30.121

17.09.29.43433

Measured

993, model

5,826.38

5, 990.

5, 667.

5,718.06

5,747.30

5,756.55

6,116.45

5,710.79

5,728.54

6,370.76

5,716.41

5,844.26

5,836.49

5, 981.12

5,556.64

5,566.46

5, 626.81

5,792.25

5, 868.18

5,868.22

5, 926.90

5,974.03

6,028.58

6,069.94

5,855.67

5,508.86

5, 641.36

5,739.73

5, 992.54

5,885.02

5,917.45

5, 832.09

6,012.34

5, 922.26

5, 921.99

6,359.22

7,005.50

6,680.39

6,721.48

6,726.44

6, 637.34

6, 686.06

6, 953.25

7,092.83

6,555.41

Model

derived

layer 1

5, 920.9

6,075.8

5, 681.2

5,747.7

5,808.2

5,808.2

6,180.5

5,768.3

5,844.8

6,189.8

5,860.8

5,821.1

5,877.3

6,001.3

5,587.6

5,587.6

5, 615.0

5,788.0

5,854.8

5,854.8

5,925.5

5, 988.9

5, 988.9

6,055.9

5,876.9

5,500.7

5,780.0

5,815.0

6,051.5

5,928.3

5,871.1

5,823.1

6,048.9

5, 919.0

5,921.3

6,368.3

6,798.5

6, 628.6

6,628.6

6,673.0

6, 688.0

6, 676.4

6, 894.6

7,150.8

6,413.3

Difference 

(model 

derived

minus

measured)

94.5

85.8

14.2

29.6

60.9

51.6

64.0

57.5

116.3

-181.0

144.4

-23.2

40.8

20.2

31.0

21.1

-11.8

-4.2

-13.4

-13.4

-1.4

14.9

-39.7

-14.0

21.2

-8.2

138.6

75.3

59.0

43.3

-46.4

-9.0

36.6

-3.3

-0.7

9.1

-207.0

-51.8

-92.9

-53.4

50.7

-9.7

-58.6

58.0

-142.1

91
Table 13.~Di£ference between measured and model-derived 

hydraulic heads, in feet Concluded

^T Hydraulic head

Row

25

25

25

25

25

25

26

26

26

26

27

27

28

31

32

 SV^LVif -1-

Column

19

20

20

21

22

24

18

21

23

24

20

22

13

17

14

Local well name

or number

17.09.32.312442

17.09.33.32142

17.09.33.2112

17.09.28.423B

17.09.27.441

17.10.31.134

17.09.31.324

16.09.03.1213A

17.09.36.4332

16.09.01.2413

16.09.08.22212

16.09.10.42114

16.08.17.2122

16.08.26.4443

16.08.33.4343

Measured

6,566.08

6,503.93

6,505.84

6,703.

6, 618.26

7,085.26

6,158.18

6,679.10

6,999.95

6, 945.43

6,581.82

6,594.

6,151.33

6,237.56

6,113.53

Model

derived

6,413.3

6,494.8

6,494.8

6,567.9

6,667.7

7,167.7

6,240.2

6,561.3

6,773.2

6, 932.5

6,444.3

6,647.8

6,231.8

6,182.6

6,095.6

Difference 

(model

minus

measured)

-152.8 -9.1

-11.0

-135.1

49.4

82.4

82.0

-117.8

-226.8

-12.9

-137.5

53.8

80.5

-55.0

-17.9

Averages for the above groups of differences, in feet

Arithmetic Mean

Group Number

Steady state, layer 1

Steady state, layer 2

Steady state, layer 3

Steady state, layer 4

Steady state, all layers

Transient, 1977, layer 1

Transient, 1993, layer 1

167

2

8

7

184

53

60

mean

13.0

41.7

53.9

39.0

16.0

13.2

-2.9

absolute

33.1

41.7

58.4

45.4

52.9

48.6

59.1

Median

13.8

41.7

44.4

28.9

16.2

21.8

-1.0

Rootmean

square

69.0

57.4

77.0

58.3

68.8

58.4

79.7

Standard

deviation

68.0

55.8

58.8

46.7

67.1

57.4

80.3

92