SUMMARY OF THE SOUTHWEST ALLUVIAL BASINS

REGIONAL AQUIFER-SYSTEM ANALYSIS IN PARTS OF

COLORADO, NEW MEXICO, AND TEXAS

COLORADO

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TEXAS

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Summary of the Southwest Alluvial Basins 

Regional Aquifer-System Analysis in Parts of 

Colorado, New Mexico, and Texas

By D.W. WILKINS

REGIONAL AQUIFER-SYSTEM ANALYSIS

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1407-A

1998
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

Thomas J. Casadevall, Acting Director

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

descriptive purposes only and does not imply endorsement by the

U.S. Government.

Library of Congress Cataloging-in-Publication Data

Wilkins, D. W.

Summary of the southwest alluvial basins regional aquifer-system analysis in parts of Colorado, New Mexico, and Texas / by D. W. 

Wilkins.

p, cm. (Regional aquifer-system analysis) (U.S. Geoloigcal Survey professional paper ; 1407-A) 

Includes bibliographical references. 

Supt.ofDocs.no. : I 19.16 : 1407-A

1. Aquifers Southwest, New. 2. Groundwater flow Southwest, New. 3. Water Chemistry. 1. Title. II. Series. 

III. Series : U.S. Geological Survey professional paper ; 1407-A. 

GB1199.3.S686W55 1997

551.49'0978 dc20 96-26992 

ISBN 0-607-88140-2 CIP

For sale by U.S. Geological Survey, Information Services

Box 25286, Federal Center

Denver, CO 80225
FOREWORD

THE REGIONAL AQUIFER-SYSTEM ANALYSIS PROGRAM

The RASA Program represents a systematic effort to study a number of 

the Nation's most important aquifer systems, which, in aggregate, underlie 

much of the country and which represent an important component of the 

Nation's total water supply. In general, the boundaries of these studies are 

identified by the hydrologic extent of each system and, accordingly, transcend the political subdivisions to which investigations have often arbitrarily been limited in the past. The broad objective for each study is to 

assemble geologic, hydrologic, and geochemical information, to analyze and 

develop an understanding of the system, and to develop predictive capabilities that will contribute to the effective management of the system. The use 

of computer simulation is an important element of the RASA studies to 

develop an understanding of the natural, undisturbed hydrologic system 

and the changes brought about in it by human activities and to provide a 

means of predicting the regional effects of future pumping or other stresses. 

The final interpretive results of the RASA Program are presented in a 

series of U.S. Geological Survey Professional Papers that describe the 

geology, hydrology, and geochemistry of each regional aquifer system. Each 

study within the RASA Program is assigned a single Professional Paper 

number beginning with Professional Paper 1400.

1.

Thomas J. Casadevall 

Acting Director

CONTENTS

	Page

Abstract............................................................................................................................................................. Al

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

Purpose and Scope .................................................................................................................................. 2

Description of the Study Area ................................................................................................................. 2

Geologic and Hydrologic Setting ............................................................................................................ 2

Summary of Basin Analyses ............................................................................................................................ 5

San Luis Basin ......................................................................................................................................... 5

Geology ........................................................................................................................................... 5

Ground-Water Flow System ............................................................................................................ 7

Albuquerque-Belen Basin ........................................................................................................................ 11

Geology ........................................................................................................................................... 12

Geochemistry .................................................................................................................................. 17

Ground-Water Flow System ............................................................................................................ 17

Socorro and La Jencia Basins ................................................................................................................. 22

Hydrology ........................................................................................................................................ 22

Geochemistry .................................................................................................................................. 24

Mesilla Basin ........................................................................................................................................... 25

Geology ........................................................................................................................................... 25

Geochemistry .................................................................................................................................. 25

Ground-Water Flow System ........................................................................................................... 28

Mimbres Basin Geology ......................................................................................................................... 30

Summary of Regional Analyses ..................................................................................................................... 30

LithologicAnalyses ................................................................................................................................ 30

Potentiometric Surface ............................................................................................................................ 31

Ground-Water Chemistry ........................................................................................................................ 35

Temperature ..................................................................................................................................... 35

Specific Conductance ...................................................................................................................... 35

Water Chemistry .............................................................................................................................. 39

Recharge .................................................................................................................................................. 41

Water Use ................................................................................................................................................ 45

Regional Synthesis .................................................................................................................................. 45

Selected References ......................................................................................................................................... 48

ILLUSTRATIONS

Page

FIGURE 1. Map showing location of Southwest Alluvial Basins study area, basin boundaries, and physiographic provinces................................................. A3

2. Map showing alluvial areas of open and closed surface-water drainage basins....................................................................................................... 4

3. Map showing generalized geology of the Southwest Alluvial Basins study area................................................................................................... 6

4. Map showing physiographic subdivisions and geographic features of the San Luis Basin..................................................................................... 8

5. Map showing ground-water-level changes in the unconsolidated unconfined valley-fill aquifer system from December 1969 to

January 1980, San Luis Basin .......................................................................................................................................................................... 13
VI CONTENTS

Page

FIGURE 6. Chart showing ground-water withdrawals and surface-water diversions for irrigation in the San Luis Basin......................................................... 14

7. Map showing principal geographic and geologic features of the Albuquerque-Belen Basin.................................................................................... 15

8. Map showing lithologic zones in the Albuquerque-Belen Basin............................................................................................................................... 16

9. Diagram showing generalized ground-water subsystems in open basins.................................................................................................................. 18

10. Graph showing ground-water withdrawals in the Albuquerque-Belen Basin and in the Rio Grande valley, 1907-79............................................ 19

11. Map showing average ground-water withdrawal in the Albuquerque area, 1956-59................................................................................................ 20

12. Map showing average ground-water withdrawal in the Albuquerque area, 1976-79................................................................................................ 21

13. Map showing cultural and geographic features of the Socorro and La Jencia Basins.............................................................................................. 23

14. Map showing cultural and geographic features of the Mesilla Basin north of the United States-Mexico international boundary ......................... 26

15. Map showing lithologic zones in the Mesilla Basin north of the United States-Mexico international boundary.................................................... 27

16. Schematic diagram showing interactions between ground water and surface water in the Mesilla Basin.............................................................. 29

17. Graph showing estimate of net irrigation flux in the Mesilla valley, 1915-75 ......................................................................................................... 30

18. Map showing lithologic zones in the Mimbres Basin................................................................................................................................................ 32

19. Map showing potentiometric surface in the basin-fill aquifer system, 1972-81....................................................................................................... 34

20. Map showing ground-water temperatures in the basin-fill aquifer system................................................................................................................ 36

21. Map showing specific conductance of ground water in the basin-fill aquifer system............................................................................................... 38

22. Map showing chemical water types in the basin-fill aquifer system......................................................................................................................... 40

23. Map showing estimated recharge to the basin-fill aquifer system............................................................................................................................ 44

24. Map showing irrigated acreage, 1978-80................................................................................................................................................................... 47

TABLES

Page

TABLE 1. Water budget for the Costilla Plains (1950-80) of the San Luis Basin...................................................................................................................... A9

2. Water budget for the Alamosa Basin (1950-80) of the San Luis Basin..................................................................................................................... 10

3. Calculated evapotranspiration for nonirrigated areas in the Alamosa Basin............................................................................................................ 11

4. Crop type, consumptive use, and evapotranspiration for irrigated areas in the Alamosa Basin.............................................................................. 12

5. Water budget for the Albuquerque-Belen Basin, 1960-61 and 1976-79................................................................................................................... 22

6. Simulated mass balance for the Mesilla Basin, pre-1915 and 1975.......................................................................................................................... 31

7. Percentage of wells in each lithologic category, by saturated interval, Albuquerque-Belen, Mesilla, and Mimbres Basins.................................. 33

8. Estimated recharge to alluvial basins......................................................................................................................................................................... 42

9. Unit recharge (ratios of total estimated recharge to alluvial area) and estimated recharge from basin boundaries per boundary length............... 43

10. Irrigated acreage in alluvial basins, 1978-80............................................................................................................................................................. 46

CONVERSION FACTORS AND VERTICAL DATUM

Multiply By To obtain

inch

foot

cubic foot

cubic foot per second

foot per second

foot per mile

mile

acre

square mile

gallon

gallon per minute

acre-foot

acre-foot per year per

square mile

25.4

0.3048

0.02832

0.02832

0.3048

0.1894

1.609

0.4047

2.590

3.785

0.06309

1,233

0.0004761

millimeter

meter

cubic meter

cubic meter per second

meter per second

meter per kilometer

kilometer

square hectare

square kilometer

liter

liter per second

cubic meter

cubic hectometer per year

per square kilometer

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 both the United States and Canada, formerly called Sea Level Datum of 1929.
REGIONAL AQUIFER-SYSTEM ANALYSIS SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND

ADJACENT STATES

SUMMARY OF THE SOUTHWEST ALLUVIAL BASINS

REGIONAL AQUIFER-SYSTEM ANALYSIS IN PARTS OF

COLORADO, NEW MEXICO, AND TEXAS

By D.W. Wilkins

ABSTRACT

The Southwest Alluvial Basins study area consists of 70,000 square miles 

in parts of Colorado, New Mexico, and Texas, and includes 22 alluvial basins 

along and adjacent to the Rio Grande. Rocks of the region can be divided into 

four basic types: (1) basin-fill deposits-unconsolidated to poorly consolidated 

sand and gravel interbedded or intermixed with clay and silt; (2) volcanics-- 

primarily basalt, including volcanic flow rocks, tuff, and small intrusive bodies; (3) consolidated sedimentary rocks-primarily shale and sandstone, 

including limestone, gypsum, and salt; and (4) crystalline rocks-intrusive 

igneous rocks and metamorphic rocks.

Structurally and hydrologically the 22 basins can be divided into two general types: open basins that have surface-water discharge and closed basins 

that have no surface-water discharge. The Rio Grande is the primary hydrologic connection among basins that have surface-water discharge. Recharge to 

the ground-water system is greater in the northern basins. About 3,580 cubic 

feet per second annually is recharged to the San Luis Basin. Recharge to the 

Mesilla Basin in southern New Mexico and western Texas annually is 6 cubic 

feet per second.

Basin-fill deposits, including fan deposits, river alluvium, and unconsolidated to consolidated sediments and some volcanics of the Santa Fe Group or 

Gila Conglomerate are hydraulically connected and form an aquifer system. 

Coarse-grained sediments were deposited by the relatively high energy ancestral Rio Grande; whereas, fine-grained lake or playa sediments were deposited 

in topographically closed basins.

Simulation of ground-water flow in the San Luis Basin indicates that of the 

535 cubic feet per second of water that was withdrawn from the basin-fill 

aquifer system in 1980, 80 percent was from salvaged evapotranspiration, 14 

percent was from aquifer storage, and 6 percent was from streamflow capture.

The total saturated thickness of sediments penetrated by wells in the Albuquerque-Belen Basin is made up of a mixture of clay, silt, and sand. Ground 

water in the southeastern part of the Albuquerque-Belen Basin contains calcium and sulfate as primary ions. Calcium generally is the dominant cation; 

bicarbonate is the dominant anion along the northeast side of the basin. 

Ground water in the flood plain of the Rio Grande generally is of a calcium 

sulfate type. A sodium chloride brine is found in the extreme southwestern 

part of the basin.

The ground-water flow model of the Albuquerque-Belen Basin shows that 

from 1976 to 1979 ground-water withdrawals outside the flood plain were 

composed of 36 percent intercepted ground-water discharge to the flood-plain 

system, 32 percent induced recharge from the flood plain; 25 percent aquifer 

storage; and 7 percent underflow from the Santo Domingo Basin, to the north.

Ground water east of the Rio Grande valley in the Socorro Basin contains 

large percentages of calcium, magnesium, and sulfate. Ground water in the 

southern part of the Rio Grande valley generally has a larger percentage of 

sodium and a smaller percentage of sulfate than ground water in the northern 

part of the valley. Water is a calcium bicarbonate type in the La Jencia Basin, 

in the principal recharge area to the east. The increase in the percent of 

sodium downgradient from the recharge area is significant.

The total saturated thickness of sediments penetrated by wells in the 

Mesilla Basin is made up of a mixture of clay, silt, and sand. Ground water is 

a sodium and sulfate type water along the northwest basin margin. Along the 

southwest basin margin one water type contains dominant ions of sodium and 

bicarbonate; another type contains dominant ions of sodium and chloride. 

West of Las Cruces chloride generally is the dominant anion in ground water.

Shallow ground water in the Rio Grande flood plain in the Mesilla Basin 

generally has a larger specific conductance than water deeper in the aquifer. 

Ground water associated with Mesozoic and Paleozoic rocks north and east of 

Las Cruces has a larger percentage of sulfate and chloride and greater specific 

conductance than water associated with volcanic rocks east of Las Cruces. 

The ground-water flow model shows that for nonirrigation ground-water withdrawals in the Mesilla Basin, 80 percent is from the surface-water system, 

including streamflow capture; 10 percent is from aquifer storage; and 10 percent is from salvaged evapotranspiration.

Ground-water movement in the study area is generally from west and east 

to the center of the valley and then southward. Through much of the study 

area the Rio Grande flood plain acts as a drain for the basin-fill aquifer 

system. Temperature of ground water from the San Luis Basin south to the 

northern end of the Albuquerque-Belen Basin generally ranges from 5 to 15 

degrees Celsius. South of the northern end of the Albuquerque-Belen Basin 

the ground-water temperature generally ranges from 15.1 to 25 degrees Celsius. Ground water generally has a specific conductance less than 750 microsiemens per centimeter at 25 degrees Celsius, north of the Albuquerque-Belen 

Basin. East of the Rio Grande and south of the Albuquerque-Belen Basin the 

specific conductance of water is usually in the range of 751 to 2,250 microsiemens per centimeter at 25 degrees Celsius.

Chemical processes affecting ground-water quality are dissolution of calcite, dolomite, gypsum, and halite; precipitation of calcite and dolomite; 

exchange of calcium for sodium; and mixing of local recharge, geothermal, or 

inflowing ground water from adjacent basins with ground water in the area of 

study. Recharge water from the east and west, in basins north of the Albuquerque-Belen Basin, is a calcium bicarbonate type; the principal chemical process is dissolution of calcite. Chloride water is found in the AlbuquerqueBelen Basin and basins to the south.

Al
A2 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

Recharge to basins is predominantly from uplifted areas east and west of 

the basins. Runoff from snowmelt and storms infiltrates the alluvial material 

near the contact of the alluvium and rocks of the uplifted areas. Recharge to 

the San Luis and Espanola Basins was estimated to be 0.984 and 0.175 cubic 

foot per second per square mile of alluvial area, respectively. Recharge rates 

in the Mesilla, Mimbres, and Lordsburg Basins, in the southern part of the 

study area, ranged from 0.004 to 0.003 cubic foot per second per square mile 

of alluvial area.

Irrigation is the primary use of surface water in open basins. In closed 

basins 93 percent of the irrigated acreage uses ground water as a source. In 

the Albuquerque-Belen Basin from 1975 to 1985, at least 90 percent of 

ground-water withdrawals were for uses other than agriculture. In the Mesilla 

Basin from 1975 to 1985, 32 to 45 percent of all ground water withdrawn was 

for nonagricultural uses.

INTRODUCTION

This report summarizes findings of the Southwest Alluvial 

Basins (SWAB) study, part of the Regional Aquifer-System 

Analysis (RASA) program of the U.S. Geological Survey in 

parts of southern Colorado, New Mexico, and west Texas. 

The main purposes of the SWAB study were to enhance the 

understanding of the regional hydrology of alluvial basins 

that serve as major ground-water reservoirs and to study the 

hydrologic effects of stresses on the system. Twenty-two 

alluvial basins are within the area. A planning report by 

Wilkins and others (1980) provides a more detailed description of the SWAB study.

The SWAB RASA is described in Professional Paper 

1407, which will consist of two parts. Part A (this report) is 

a summary of the study. Part C (Frenzel and Kaehler, 1992) 

describes the geohydrology and ground-water quality of the 

Mesilla Basin. A summary of ground-water flow models 

planned as Part B of Professional Paper 1407 has been 

released as Open-Rile Report 90-361 (Kernodle, 1992) and is 

not included as a Professional Paper chapter.

PURPOSE AND SCOPE

This report summarizes studies of selected basins and discusses water quality, ground-water flow systems, and water 

use in the study area as a whole. Selected basins were studied in detail using various geohydrologic techniques. Geology, ground-water flow, ground-water geochemistry, groundwater recharge, and aquifer characteristics were studied. Digital flow models of the ground-water systems were developed 

for three basins. The techniques used and results of basin 

studies are presented in reports for the individual basins.

DESCRIPTION OF THE STUDY AREA

The study area includes parts of four physiographic provinces (fig. 1). The northern part of the study area is within 

the Southern Rocky Mountains province. The Basin and 

Range province includes most of the study area south of the

Espanola Basin. The Colorado Plateau province includes 

small areas of the Albuquerque-Belen and San Agustin 

Basins. The Great Plains province lies along the east edge of 

the study area.

The study area is structurally and hydrologically divided 

into 22 basins of two general types: open basins that have 

surface-water discharge and closed basins that have no surface-water discharge. The Rio Grande is the primary hydrologic connection among basins that have surface-water 

discharge in southern Colorado, central New Mexico, and 

western Texas (fig. 2). Closed basins primarily are in southwestern and south-central New Mexico and western Texas. 

Of about 70,000 square miles in the study area, 7,500 square 

miles are in Colorado, 53,000 square miles are in New Mexico, and 9,500 square miles are in Texas.

GEOLOGIC AND HYDROLOGIC SETTING

The Rio Grande rift is a fault-bounded structural feature 

with uplifted blocks on the east and west and downdropped, 

alluvial-filled grabens in the middle. Rifting began about 26 

million years ago (Chapin and Seager, 1975). Structural models and the observed fault patterns indicate that either regional 

extension caused by differential drift within the continental 

plate (Chapin, 1971; Kelley, 1977) or broad regional uplift 

(Baltz, 1978) resulted in downdropped basins (grabens) and 

tilted fault blocks that formed the Rio Grande depression. 

Woodward and others (1975, p. 239) placed the rift's southern 

limit at Socorro, New Mexico. Seager and Morgan (1979, p. 

101) extended the rift into western Texas and northern Mexico, on the basis of shallow manifestations of the deep structure, such as "active faults and volcanoes, high heat flow, and 

exceptionally deep basins." The tectonic map by Woodward 

and others (1975) shows "generally thick, synorogenic sedimentary deposits in the Rio Grande rift; Miocene to 

Holocene" as far south as Presidio, Texas. Rifting took place 

along a general north-south structural grain, probably in 

response to east-west extension. The basins and bounding 

uplifts generally are arranged en echelon with each basin or 

uplift being offset slightly to the east of the one to its south. 

This pattern, together with gravity anomaly lineaments, indicates that the crust broke along north-northeast and northnorthwest trends oblique to the main north-south structural 

grain (Ramberg and others, 1978). Uplifted blocks to the east 

of the basins generally rise several thousand feet above the 

valley floor. The basins are bounded on the north, east, and 

west mainly by Paleozoic and Mesozoic sedimentary rocks 

and Tertiary and Quaternary volcanics. The southern boundary of the study area is arbitrarily placed at the Mexico-United 

States international boundary. Detailed descriptions of bordering rocks and geologic features can be found in Chapin 

(1971), Hawley (1978), and Riecher (1979). Other geologyrelated publications are listed in bibliographies by Stone and 

Mizell (1979) and Wright (1978, 1979a, b).
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A3

OUTHERNO *f'

ROCKY \ Q 

MOUNTAIN > 

PROVINCE 2

, BASIN AND I 

 RANGE

PROVINCE

EXPLANATION

Area of basin fill Indicates extent 

of basin fill within basin boundaries 

as defined by this study

Province boundary

Basin boundary Number and 

name listed below

1. San Luis

2. Espanola

3. Santo Domingo

4. Albuquerque-Belen

5. Socorro

6. La Jencia

7. San Agustin

8. San Marcial

9. Engle

10. Palomas

11. Jornada Del Muerto

12. Mesilla

13. Tularosa-Hueco

14. Mimbres

15. Hachita

16. Playas

17. Animas

18. Lordsburg

19. Salt

20. Eagle

21. Redlight Draw

22. Presidio

LOCATION MAP

FIGURE I. Location of Southwest Alluvial Basins study area, basin boundaries, and physiographic provinces. (Modified from Wilkins,

1986b, fig.64.)
A4 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

MONTEZUMA -^ i I -0 rtiyaa ' ^ x

I ' LAPI.ATA 1 ti U^H n- r 1

} ARCHULETA ]rONEJOSJJf /

i COLORADO ____ [ ____ f>\ ^Tt^j£

NEW MEXICO~ ~ I ~ J I S ' 

I ^r '- '.

' J \ S 'i

EXPLANATION

Areas that have open 

surface-water drainage

Areas that have closed 

surface-water drainage

FIGURE 2. Alluvial areas of open and closed surface-water drainage basins.
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A5

Basin boundaries are defined by the contact of alluvial fill 

and the toe of uplifted blocks. The hydrologic boundary for 

many basins, however, is a basin-bounding fault, usually buried by alluvial material. On the basin side of these faults, 

generally there is a substantial thickness of alluvial sediments. 

Structurally, several of the basins in the southern part of the 

study area extend into Mexico. Hydrologically, these areas 

are not considered significant because the basin aquifers 

receive small to negligible amounts of recharge from the south 

and are not stressed by ground-water withdrawals in Mexico.

West and Broadhurst (1975, p. 11-13) divided rocks of the 

region into four basic types: (1) basin-fill deposits unconsolidated to poorly consolidated sand and gravel interbedded or 

intermixed with clay and silt; (2) volcanics primarily basalt, 

including volcanic flow rocks, tuff, and small intrusive bodies; (3) consolidated sedimentary rocks primarily shale and 

sandstone, including limestone, gypsum, and salt; and (4) 

crystalline rocks intrusive igneous rocks and metamorphic 

rocks. For this study the first two types, consisting of Quaternary and Tertiary basin-fill deposits and volcanics, were considered to comprise the basin-fill aquifer system; the last two 

types, consisting primarily of Mesozoic through Precambrian 

rocks, were considered impermeable bedrock (fig. 3).

Quaternary deposits primarily consist of alluvial fans, 

colluvium, pediment gravels and sands (including dunes), 

playa muds and sands, river terraces, and inner river-valley 

flood-plain and channel deposits. With the exception of the 

flood-plain and channel deposits, Quaternary sediments are 

usually unsaturated.

The Tertiary and Quaternary Santa Fe Group, or Gila Conglomerate, is present throughout the study area. It consists 

of unconsolidated to moderately consolidated sedimentary 

deposits and some volcanic rocks. Bryan (1938, p. 205) 

used four criteria in defining the Santa Fe Formation:

(1) All the beds are slightly cemented, and the finegrained members have concretions of calcium carbonate;

(2) all the deposits are deformed, mostly by normal faults, 

although in the centers of the basins the deformation is so 

slight as to pass unnoticed except under intensive search;

(3) the beds within any one basin are of diverse lithologic 

types, ranging from coarse fanglomerate to fine silt and 

clay, and abrupt changes in the kind and size of the contained pebbles are characteristic; (4) and these markedly 

different materials attributed to one formation conform in 

their arrangement to a geographic pattern consistent with 

the laws of deposition in basins.

The base of the Santa Fe Group generally is placed above 

the middle Tertiary (Oligocene) volcanic and associated sedimentary rocks. Estimated thicknesses of sediments in closed 

basins range from about 2,400 feet in the Salt Basin to 

about 6,000 feet in the Jornada del Muerto Basin. Sediment 

thicknesses in open basins associated with the Rio Grande 

rift are as much as 20,000 feet in the San Luis Basin 

(Tweto, 1978, p. 27).

The basin-fill deposits, including fan deposits, alluvium 

within river valleys, and the Santa Fe Group or the Gila 

Conglomerate, form the hydraulically connected, anisotropic, 

and heterogeneous principal basin-fill aquifer system. 

Ground water within the first several hundred feet of saturated sediments generally is unconfined, but confined conditions may exist locally. Recharge, derived from precipitation 

in the surrounding mountain areas, occurs primarily near 

basin-bounding faults. Sediments, with sufficient saturated 

thickness to supply water to wells, are usually found on the 

basin side of these faults

The Rio Grande is the major source of surface water in the 

study area. The Rio Grande originates along the eastern 

crest of the Continental Divide in southern Colorado, flows 

eastward into the San Luis Basin some 65 miles east of its 

headwaters, and then flows generally southward (fig. 1). 

Most surface water is diverted into canals south of the Santo 

Domingo Basin.

SUMMARY OF BASIN ANALYSES

Five of the 22 basins were studied in detail. These basins 

were selected on the basis of availability of data and groundwater development that lead to significant stress on the 

ground-water system in the basins. The following sections 

summarize results of the basin studies; additional information about the studies is available in the cited publications.

SAN LUIS BASIN

The San Luis Basin is in southern Colorado and northern 

New Mexico (fig. 1). It was selected for study because of a 

long history of ground-water withdrawals for irrigation in the 

San Luis Valley, north of the San Luis Hills.

GEOLOGY

Seismic-reflection data were collected east and west of the 

southern San Luis Hills near the Colorado-New Mexico State 

line as part of this project (Uitti, 1980, p. 10). Depth to the 

Precambrian basement rocks ranges from about 8,500 feet 

east of the Rio Grande to about 1,500 feet west of the river 

in the vicinity of the southern end of the San Luis Hills 

(Uitti, 1980, p. 42). East of the southern end of the San Luis 

Hills (fig. 4), the thickness of alluvial sediments, including 

the Santa Fe Group, is about 2,600 feet. A maximum thickness of 4,200 feet is indicated east of the hills in the vicinity 

of the Colorado-New Mexico State line. Alluvial sediments 

younger than the Santa Fe Group are about 1,300 feet thick 

west of the Rio Grande near the southern San Luis Hills 

where the Santa Fe Group is absent (Uitti, 1980, p. 38).
A6 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

EXPLANATION

Quaternary-Tertiary basin-fill deposits 

Includes flood-plain sediments of Rio 

Grande and its tributaries, fan deposits, 

and the Santa Fe Group and Gila Conglomerate of Pliocene and Pleistocene 

age. These sediments collectively are 

the principal aquifer in the study area. 

Wells completed in these sediments 

produce from a few gallons per minute 

to several thousand gallons per minute

Quaternary and Tertiary volcanics 

Usually present as mesas in the study 

area. In places the volcanics overlie the 

sediments of the Santa Fe Group and 

can be interbedded with sediments of the 

Santa Fe Group. May be saturated and 

are considered part of the aquifer system 

where they occur at depth

Mesozoic and Paleozoic rocks, undivided 

Considered to be impermeable bedrock

Precambrian rocks Considered to be 

impermeable bedrock

FIGURE 3. Generalized geology of the Southwest Alluvial Basins study area. (From Wilkins, 1986b, fig. 66).
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A7

GROUND-WATER FLOW SYSTEM

The major components of the ground-water flow system in 

the San Luis Basin were analyzed to provide estimates of flow 

rates between these components. Additionally, the analyses 

were made to improve estimates of hydrologic changes in the 

ground-water flow system in response to management alternatives in the Alamosa Basin (Hearne and Dewey, 1988). 

Boundaries of the basin are the drainage divides in the Sangre 

de Cristo Mountains on the east and the San Juan Mountains 

on the west (fig. 4). The intermontane area is divided by the 

San Luis Hills into the Alamosa Basin to the north and the 

Costilla Plains and the Taos Plateau to the south. The Alamosa 

Basin is dissected by a low topographic divide, forming a 

closed basin north of the Rio Grande drainage basin.

The intermontane area contains several thousand feet of 

interbedded sedimentary and volcanic rocks that form complex aquifer systems. The San Luis Hills are a barrier to 

ground-water flow between the Alamosa Basin and the Taos 

Plateau or Costilla Plains.

The San Juan Mountains and the Sangre de Cristo Mountains are the source of most water for the Alamosa Basin, the 

Costilla Plains, and the Rio Grande. In the mountains, precipitation exceeds evapotranspiration, and excess water flows 

to the intermontane area. Water yield (surface flow and 

ground-water flow) from the San Juan Mountains is about 

2,800 cubic feet per second (ft3/s). Water yield from the Sangre de Cristo Mountains is about 780 ft3/s (Hearne and 

Dewey, 1988, p. 110).

Hearne and Dewey (1988) calculated water budgets for the 

Costilla Plains and the Alamosa Basin. These water budgets 

represent average values for 1950-80. Two methods of estimating recharge were developed by Hearne and Dewey 

(1988). The mountain water-budget method was used in 

uplifted areas with significant secondary permeability. The 

method computes a volume of water that will infiltrate within 

and flow from the uplifted area. The mountain water-budget 

method is based on the following equation (Hearne and 

Dewey, 1988, p. 15, eq. 1).

Q = P-S-E (1)

where Q = sum of streamflow and ground-water flow 

to the alluvial basin (L3/T),

P = precipitation (LVT), 

5 = sublimation (L3/T), and 

E = evapotranspiration (L3/T).

Temperature was used to determine whether precipitation 

was added to storage in the snowpack or to the root zone and 

to calculate the volume of snowmelt to be moved from the 

snowpack to the root zone. Water in excess of the storage 

capacity of the root zone was assumed to flow to the alluvial 

basin either as streamflow or ground-water flow (Hearne and 

Dewey, 1988, p. 15).

The mountain water-yield method was used to compute 

water yield for uplifted areas in which secondary permeability is negligible and all discharge from the drainage basin is 

assumed to be in surface streams. Discharge of surface water 

into the alluvial basin was assumed to be by infiltration 

through streambed sediments on the basin side of basinbounding faults and is called mountain-front recharge.

The mountain water-yield method uses a multiple-linear 

regression of mean annual water yield against mean winter 

precipitation and the area of drainage. The regression equation (Hearne and Dewey, 1988, p. 31, eq. 8) is

Q= 7.62 x io-5 A0-977 P3 -596 (2)

where Q = mean annual water yield, in cubic feet per 

second (L3/T);

A = area of the drainage basin, in square miles (L2); 

and

P = mean winter precipitation, in inches (L).

Estimates of recharge using one of these methods were made 

for all basins in the study area.

For the Costilla Plains water budget (table 1), the change 

in the volume of water stored beneath the Costilla Plains was 

assumed to be negligible. Precipitation was estimated to 

average 1.0 foot per year. Precipitation on the 430,000 acres 

of the Costilla Plains was calculated to be 590 ft3/s. Evapotranspiration from the Costilla Plains was assumed to depend 

on depth to water and land use. Three categories were considered: (1) water-course and riparian areas; (2) nonirngated 

areas; and (3) irrigated areas.

Water-course and riparian areas include those along the 

Rio Grande from the San Luis Hills to Embudo, New Mexico, irrigation canals, stock ponds, reservoirs, and streams on 

the Costilla Plains. For these areas, water is at or near the 

land surface. For the 4,000 acres (estimated from U.S. Geological Survey topographic maps) of water-course and riparian areas in the Costilla Plains, evapotranspiration was 

assumed to be 4.5 feet per year. The resulting loss to the 

atmosphere was calculated to be 25 ft3/s.

For other nonirrigated areas, evapotranspiration was 

assumed to be limited by precipitation. Precipitation from 

each storm event was assumed to be stored as soil moisture 

and returned to the atmosphere by evapotranspiration. Precipitation was estimated from isohyetal maps (National Oceanic and Atmospheric Administration, 1980) to average about 

1.0 foot per year. Therefore, evapotranspiration from the estimated 340,000 acres of nonirrigated land in the Costilla 

Plains was calculated to be 470 ft3/s.

For irrigated areas, evapotranspiration was estimated from 

irrigated acreage, average depletion, and precipitation. Total 

irrigated acreage of the Costilla Plains was estimated to be 

84,000 acres. Precipitation on irrigated and nonirrigated 

acreage was estimated to be 1.0 foot per year. Therefore, 

precipitation on the 84,000 acres of irrigated land was calculated to be 120 ft3/s.
A8 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

106°00'

APPROXIMATE

STUDY-AREA

BOUNDARY

ALAMOSA BASIN

EXPLANATION 

Mountains or hills 

Alamosa Basin 

Taos Plateau 

Culebra Reentrant 

Costilla Plains CO L O RAD 

NEW MEXICO Fault Approximately located COSTILLA 

PLAINS

20 30

I

40 MILES

I I I I I 

0 10 20 30 40 KILOMETERS

FIGURE 4. Physiographic subdivisions and geographic features of the San Luis Basin. (Modified from Hearne and Dewey, 1988, fig. 2.)
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A9

TABLE 1. Water budget for the Costilla Plains (1950-80) of the San Luis Basin.

[From Hcarne and Dewey, 1988, table 13. All estimates are in cubic feet per second]

Flow source Estimated flow

Inflow

Sangre de Cristo Mountains........................

Taos Plateau................................................

Precipitation on the Costilla Plains.............

Rio Grande, near Lobatos, Colorado..........

Ground-water flow past the San Luis Hills.

.440 

...28 

.590 

.350 

..C1 )

Total inflow..............................................................................................................l,408

_______________________Outflow_____________

Evapotranspiration from the Costilla Plains ....................................................................740

(Nonirrigated areas--490 (rounded).

Irrigated areas--250). 

Rio Grande, nearEmbudo, New Mexico.........................................................................680

Total outflow............................................................................................................l,420

Not estimated.

In addition to precipitation, irrigation withdrawals were 

made from surface and ground-water sources for application 

to irrigated areas. Irrigation depletion is the amount of water 

from surface-water and ground-water withdrawals that is 

consumed by crops or lost to the atmosphere during irrigation. A depletion rate of 1.14 feet per year was used to calculate a depletion of 130 ft3/s for the 84,000 irrigated acres in 

the Costilla Plains (Hearne and Dewey, 1988, p. 40-41). 

Ground-water discharge at Embudo, New Mexico, is 

assumed to be negligible.

On the Taos Plateau for 1950-80, precipitation is estimated 

to exceed evapotranspiration by 28 ft3/s. About 28 ft3/s is 

estimated to flow through fractured volcanic rocks and discharge as spring flow or seepage flow to the Rio Grande.

Ground-water inflow to the Costilla Plains through and 

around the San Luis Hills cannot be measured directly. Inadequate definition of the transmissivity of the volcanic rocks 

of the San Luis Hills precludes an independent estimate of 

inflow using the hydraulic gradient (Hearne and Dewey, 

1988, p. 40-41). "To balance the water budget, inflow 

should equal outflow. Ground-water inflow was calculated as 

the residual of the water budget to be about 10 cubic feet per

second by subtracting other estimated inflows from estimated 

outflow. Because the flow is small relative to other items in 

the budget, this estimate is not accurate and was not included 

in table 13" [table 1 in this report] (Hearne and Dewey, 

1988, p. 41).

The water budget for the Alamosa Basin (table 2) shows 

the estimated rates of inflow, outflow, and change in storage 

for 1950-80. Irrigation development is extensive only in the 

Alamosa Basin. Surface-water irrigation has been extensive 

since about 1890. Significant ground-water irrigation began 

about 1950. Recharge was estimated using the previously 

described methods. Precipitation was estimated to be 0.64 

foot per year. Evapotranspiration was assumed to depend on 

land use and depth to water. Evapotranspiration consumes 

water from both precipitation and ground water. For nonirrigated areas, calculated evapotranspiration was dependent on 

depth to water. For nonirrigated areas, evaporation was 

assumed to consume ground water to meet part of the vegetation demand. Evapotranspiration from ground water in 

water-course and riparian areas along the Rio Grande and 

Conejos River was assumed to be 4.5 feet per year. Evapotranspiration from ground water in other areas where the
A10 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

TABLE 2. Water budget for the Alamosa Basin (1950-80) of the San Luis Basin.

[From Hearne and Dewey, 1988, table 17. All estimates are in cubic feet per second]

Flow source Estimated flow

Inflow

Sangre de Cristo Mountains.............................................................................................340

San Juan Mountains......................................................................................................2,800

Precipitation on the Alamosa Basin..............................................................................1,500

Total inflow................................................................................................................4,640

Decrease of storage in the aquifer 

Alamosa Basin...................................................................................................................87

_______________________Outflow______________

Evapotranspiration from the 

Alamosa Basin............................................................................................................3,900

(Nonirrigated areas-2,000. 

Irrigated areas-1,900) 

Rio Grande, near Lobatos, Colorado ...............................................................................350

Ground-water flow past the San Luis Hills....................................................................... C 1 )

Total outflow..............................................................................................................4,250

Not estimated.

depth to water was less than 2 feet was assumed to be 3.1 

feet per year (69 percent of that from water courses). Similarly, evapotranspiration from ground water (table 3) was 

estimated for other depth-to-water zones (Hearne and Dewey, 

1988, p. 43-46).

Within the irrigated areas, calculated evapotranspiration 

was dependent on crop type and an assumed depth to water. 

Evapotranspiration includes consumptive use required by the 

crop. Of the 710,000 acres irrigated in the Alamosa Basin, 

320,000 acres were harvested; 210,000 acres (30 percent) 

were assumed to be nonirrigated pasture; and the remaining 

180,000 acres were assumed to be irrigated pasture. Consumptive use for four major crops-alfalfa, grass, spring 

grains, and potatoes was estimated. The consumptive use for 

each crop was assumed to be supplied by a combination of 

irrigation, shallow ground water, and precipitation. Table 4 

shows the crop types, area of each crop, consumptive use, 

and evapotranspiration for irrigated lands. All precipitation 

on irrigated areas was assumed to be returned to the atmosphere by evapotranspiration.

The Rio Grande flows through the Alamosa Basin from 

Del Norte, Colorado, to the gap in the San Luis Hills. Flow 

in the Rio Grande near Del Norte, Colorado, is included in 

the estimated inflow from the San Juan Mountains. Average 

outflow in the Rio Grande near Lobatos, Colorado, averaged 

350 ft3/s for 1950-80.

The decrease in the volume of water stored beneath the 

Alamosa Basin from 1950 through 1969, estimated from an 

analog model simulation, was 730,000 acre-feet; 70 percent 

was from the unconfined aquifer, and 30 percent was from 

the confined aquifer (Emery and others, 1975, table 5). From 

1970 to 1980, the decrease in storage in the unconfined aquifer, estimated from change in hydraulic heads, was 860,000 

acre-feet (Crouch, 1985). The storage decrease in the unconfined aquifer was assumed to be 70 percent of the total. Total 

storage decrease for both the unconfined and confined aquifers was about 1,200,000 acre-feet. From 1950 to 1980, storage was estimated to decrease about 1,900,000 acre-feet 

based on the estimates presented previously (Hearne and 

Dewey, 1988, p. 50).
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES All

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The approximate areal extent of water-level changes from 

December 1969 to January 1980 in the unconfined valley-fill 

aquifer system of the San Luis Basin is shown in a waterlevel-change map (fig. 5). According to Crouch (1985, sheet 

1), "There are several factors that may have contributed to 

the general water-level decline in the San Luis Valley during 

the 1970's. These include an increase in ground-water withdrawals from the unconfined aquifer for irrigation of an 

expanded acreage and a decrease in surface-water diversion 

with a resultant decrease in ground-water recharge."

Annual ground-water withdrawals for 1940-79 vary from 

3,000 acre-feet (less than 1 percent) of total irrigation water 

used in 1941 to greater than 981,000 acre-feet (66 percent) 

in 1977, an atypical year for surface-water diversions. 

Ground-water withdrawals and surface-water diversions for 

1940-79 are shown in figure 6.

A preliminary analysis of the Alamosa Basin using a twodimensional cross-sectional model concluded that (1) a 

seven-layer model, representing 3,200 feet of saturated thickness, could accurately simulate the behavior of the flow system, and (2) the 1950 condition was approximately stable 

and would be a satisfactory initial condition. Subsequently, a 

seven-layer, three-dimensional areal model was constructed 

to represent the aquifer system in the Alamosa Basin (Hearne 

and Dewey, 1988). Values of aquifer characteristics were 

assumed or estimated from the work of previous investigators. Recharge and discharge were defined to represent the 

changes since 1950 in ground-water withdrawals, return flow, 

salvaged evapotranspiration, and streamflow capture. Hydrologically consistent modifications to ground-water withdrawals resulted in simulated head changes approximating the 

measured data water-level declines within 6 feet or less for 

1950-69 and water-level declines within about 5 feet of measured values for 1970-79. The sources of the 535 ft3/s of 

water withdrawn from the aquifer system in 1980 were 80 

percent from salvaged evapotranspiration, 14 percent from 

storage in the aquifer, and 6 percent from streamflow capture 

(Hearne and Dewey, 1988, p. 111).

Sensitivity tests on the three-dimensional model indicated 

that simulated 1970-79 hydraulic-head declines were most 

sensitive to ground-water withdrawals. However, for most of 

the simulations, salvaged evapotranspiration was the major 

source (69 to 82 percent) of ground-water withdrawals. The 

simulations implied that evapotranspiration of ground water 

does occur in irrigated areas and that evapotranspiration has 

decreased as hydraulic head has declined (Hearne and 

Dewey, 1988, p. 111).

ALBUQUERQUE-BELEN BASIN

The Albuquerque-Belen Basin in central New Mexico (fig. 

7) contains the city of Albuquerque and surrounding metropolitan area. This basin was selected for detailed study 

because water use has increased significantly, primary land 

use has changed from agricultural to urban, and wells are 

being drilled deeper and farther from the Rio Grande as the 

metropolitan area expands.
A12 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

TABLE 4. Crop type, consumptive use, and evapotranspiration for irrigated areas in the Alamosa Basin.

[From Hearne and Dewey, 1988, p. 48. ft/yr, feet per year; ft3/s, cubic feet per second]

Crop type

Alfalfa................................

Other hay.. ..........................

Grain..................................

Potatoes..............................

Irrigated pasture .................

Nonirrigated pasture...........

Total (rounded)

Area 

(acres)

......... 99,000

......... 91,000

......... 96,000

......... 34,000

......... 180,000

......... 210,000

710,000

Consumptive 

use 

(ft/yr)

2.2 

1.8 

1.2 

1.4 

1.8 

(! )

Evapotranspiration 

(ft/yr) (ft3/s)

2.4 

2.0 

1.6 

1.8 

2.0 

1.7

330 

250 

210 

85 

500 

490

1,900

*Not estimated separately.

GEOLOGY

The description of the structure and geology of the Albuquerque-Belen Basin is excerpted from Kernodle and others 

(1987, p. 12, 17). The structural basin is 35 to 40 miles in 

width and about 100 miles in length. The basin is bounded 

on the east and west sides by faults. Total fault displacement 

along the east side of the Rio Grande rift is 5,000 to 6,000 

feet greater than that along the west side. Sandia and Hubbell Springs faults (fig. 7) separate the basin from the Sandia, 

Manzanita, and Manzano Uplifts on the east; whereas, 

numerous faults with less displacement separate the basin 

from Sierra Lucero, the Ladron Mountains, and the San Juan 

Basin on the west. These faults, having elevated benches of 

pre-Santa Fe Group bedrock near or at the present-day land 

surface, mark the east and west boundaries of the regional 

ground-water system in the Albuquerque-Belen Basin. The 

southern end of the basin is terminated by converging faults 

and bedrock highs at the San Acacia constriction. Floodplain alluvium and a thin layer of Santa Fe Group deposits 

are present within the constriction, allowing some groundwater outflow southward to the Socorro Basin. The northern 

end of the Albuquerque-Belen Basin, as defined in this investigation, is at the southern and southeastern edge of the 

Jemez volcanic complex and along the southern and southwestern edge of Santa Ana Mesa. The central part of the 

Albuquerque-Belen Basin has been downfaulted in relation 

to the bordering highlands. Material derived by erosion of 

the highlands and sediment transported into the basin by the 

Rio Grande and other streams have filled the graben to a 

thickness locally in excess of 18,000 feet.

The areal distribution of lithologic sediment types for the 

total saturated depth analyzed is 20 to 50 percent clay, silt, 

mudstone, shale, or caliche in a band north to south throughout the central part of the basin (Kaehler, 1990) (fig. 8).

Sediments containing more than 50 percent sand, gravel, 

cobbles, or boulders are more prevalent in the Albuquerque 

area and to the north. Sediments containing more than 50 

percent clay, silt, mudstone, shale, and caliche are found 

along the western side of the basin adjacent to Albuquerque.

The areal distribution of saturated lithologic types for 100- 

foot-thick intervals to a depth of about 600 feet is basically 

the same as that for the total depth. In the interval from 600 to 

900 feet below the water table, the coarse-grained sediments 

are found around Albuquerque and areas to the west and 

north; fine-grained sediments are found in the southern part of 

the basin. Generally, coarse-grained sediment is the predominant type to a depth of 600 feet below the water table. Below 

600 feet, fine-grained sediments, or occasionally fine-grained 

mixed sediments, are predominant (Kaehler, 1990).

Analyses of borehole-geophysical logs suggest that the 

basin fill consists of sand lenses alternating with clay or silt 

lenses. The layering appears to be random; individual lenses 

cannot be traced from well to well. The clay lenses have a 

maximum thickness of 45 feet and are more common on the 

eastern side of the basin.

Analyses of gravity data (Birch 1980a, p. 19) show that 

the Albuquerque-Belen Basin is separated from the Santo 

Domingo Basin to the north by Neogene sediments less than 

3,300 feet thick, defined by Birch (1980a, p. 5) as the upper 

Tertiary Santa Fe Group and Quaternary sediments. In most 

of the Albuquerque-Belen Basin the Neogene-sediment thickness is about 4,900 feet. A north-trending zone of Neogene 

sediments with a thickness of 6,500 to 8,200 feet (Birch, 

1980a, p. 19) is present on the east side of the basin. In the 

southern Albuquerque-Belen Basin, the depth to Precambrian 

rocks decreases from 9,800 feet to near land surface north of 

the constriction between the Albuquerque-Belen and Socorro 

Basins (Birch, 1980a, fig. 22).
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A13

106°00'

106°30'

Water-level change, in feet, within the 

approximate limit of alluvial sediments

^^^B Rise more than 10 feet

m 5 to 10

L - j ° to 5

-5toO

-10 to -5

-20 to -10

Decline more than 20 feet

No data available

Approximate limit of 

alluvial sediments

Approximate studyarea boundary

20

I

30

I

40 MILES

I I 1 I I 

0 10 20 30 40 KILOMETERS

FIGURE 5. Ground-water-level changes in the unconsolidated, unconfined valley-fill aquifer system from December 1969 to January 1980, San Luis

Basin. (Modified from Crouch, 1985.)
A14 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

2.5

mi Surface-water diversions 

I I Ground-water withdrawals

YEAR

FIGURE 6. Ground-water withdrawals and surface-water diversions for irrigation in the San Luis Basin. (From

Hearne and Dewey, 1988, fig. 23.)

Analyses of surface-resistivity data resulting from surveys 

west of the volcanoes that are west of Albuquerque produced 

estimates of porosity ranging from 11 to 22 percent at a 

depth of 9,500 feet (Jiracek, 1982, p. 46). Porosity above this 

depth was not estimated because of lack of confidence in 

values of in situ resistivity of the formation water.

Southwest of the volcanoes west of Albuquerque (fig. 7) 

and just north of Interstate 40, bipole-dipole mapping indicated a northwest- to southeast-oriented ridge of high resistivity. Dipole-dipole mapping indicated a highly resistive 

zone, possibly overlain by a less resistive zone (Jiracek, 

1982, p. 54). Conductive saline waters may move over Cretaceous basement rock due to the eastward hydraulic gradient 

or upward movement of deep saline water along faults. 

Depth to the top of this horstlike feature is from 660 to 820 

feet. A zone of increased temperature gradients corresponds 

to the suspected horst (Jiracek, 1982, p. 66). The presence of

increased temperature gradients in the area supports the possibility that deep geothermal water could be flowing over an 

uplifted bedrock mass.

A surface-resistivity survey was conducted at the southern 

end of the Albuquerque-Belen Basin. The survey indicated 

that the water table is at a depth of 38 feet, ground water has 

an equivalent sodium chloride concentration of 1,500 milligrams per liter, and the aquifer matrix has a porosity of 28 to 

43 percent to a depth of about 154 feet. Between 154 and 

200 feet below land surface, the porosity of the aquifer 

matrix is less than that estimated for the overlying sediments, 

and ground water is estimated to contain 5,000 milligrams 

per liter as equivalent sodium chloride. From 200 to about 

1,300 feet below land surface, porosity probably is less than 

that of overlying sediments, and the salinity of ground water, 

expressed as sodium chloride, is about 8,000 milligrams per 

liter. Basement rock, possibly Paleozoic in age, is below 

1,300 feet (Jiracek, 1982, p. 84-85).
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A15

EXPLANATION

] Volcanic feature

J Flood-plain deposits

 Fault

Approximate basin 

boundary

20 KILOMETERS

FIGURE 7. Principal geographic and geologic features of the Albuquerque-Belen Basin. (Modified from Kernodle and Scott, 1986, fig. 3.)
A16 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

EXPLANATION

Area where wells penetrate 

mostly sand, gravel, cobbles, 

and boulders

Area where wells penetrate 

mostly clay, silt, mudstone, 

shale, and caliche

Area where wells penetrate 

between 20 and 50 percent 

clay, mudstone, shale, or 

caliche; less than 70 percent 

sandstone, conglomerate, 

limestone, or volcanics; and 

less than 70 percent sand, 

gravel, cobbles, or boulders

Area where wells penetrate 

a mixture of lithologies

Area of insufficient data to 

categorize lithology

Approximate basin boundary

10 20 KILOMETERS

FIGURE 8. Lithologic zones in the Albuquerque-Belen Basin. (Modified from Kaehler, 1990, fig. 5.)
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A17

GEOCHEMISTRY

Surface-water quality in the Albuquerque-Belen Basin is 

variable depending on the stream. Average specific conductance of water from September 1969 to August 1982 in the 

Jemez River was 1,283 microsiemens (microsiemens per 

centimeter at 25 degrees Celsius); in the Rio Puerco, near the 

confluence with the Rio Grande, it was 2,047 microsiemens; 

and in the Rio Salado, in the southwestern part of the basin, 

it was 1,670 microsiemens (Anderholm, 1988, p. 32). All of 

these streams empty into the Rio Grande within the Albuquerque-Belen Basin. For the same period, the specific conductance in the Rio Grande in the northern part of the basin 

was 358 microsiemens; whereas, downstream in the southern 

part of the basin it was 752 microsiemens. The downstream 

increase is attributed to solute concentration through evapotranspiration, tributary inflow, and return flow of excess irrigation water (Anderholm, 1988, p. 33).

Ground-water quality in the basin also is variable. The 

southeastern part of the basin contains water with calcium 

and sulfate as primary ions; specific conductance ranges 

from 1,000 to 1,200 microsiemens. Calcium is the dominant 

cation and bicarbonate generally is the dominant anion along 

the east side of the basin where ground-water quality is 

affected primarily by recharge of runoff from the high mountains. Ground water from the mountains to just east of the 

Rio Grande has a specific conductance of less than 400 

microsiemens. Specific conductance of ground water in the 

flood plain of the Rio Grande south of Los Lunas ranges 

from 281 to 2,170 microsiemens (Anderholm, 1988, p. 59). 

The increased specific conductance probably is due to mixing of excess irrigation-return water with resident water in 

the aquifer system. Specific conductance of water west of the 

Rio Grande flood plain but east of the vicinity of the Rio 

Puerco ranges from about 500 to 900 microsiemens.

On the western side of the southern Albuquerque-Belen 

Basin, sodium chloride brine, containing specific conductance as large as 91,000 microsiemens, enters the basin-fill 

aquifer system. The brine then flows south and east, mixing 

with ground water in the basin. Specific conductance of the 

water in the general area of mixing varies from about 400 to 

9,000 microsiemens because of different mixing ratios of the 

inflowing brine and existing ground water. In general, the 

specific conductance of the mixed water decreases as it 

moves eastward because of dilution of the brine with less 

saline recharge water from the east. The mixed water in this 

area dissolves gypsum as the water moves through the aquifer system, as indicated by a general increase in percentages 

of calcium and sulfate in the mixed water in comparison 

with percentages of calcium and sulfate in the brine. In the

southwestern part of the basin, ground water has large chloride concentrations. These elevated chloride concentrations 

are probably due to upward movement of deep circulation 

water. The upward movement probably is caused by a constriction of ground-water flow in the extreme southern end of 

the basin (Anderholm, 1988, p. 77).

The overall ground-water quality in the northern part of 

the basin is a result of mixing of waters from the Jemez geothermal reservoir to the north and ground water in the basinfill aquifer system (Anderholm, 1988, p. 101). Concentrations of chloride, as large as 1,300 milligrams per liter (mg/ 

L), and of silica, as large as 91 mg/L, are found. These constituents generally are indicators of ground-water flow from 

the Jemez geothermal reservoir.

Sodium is the dominant cation in ground water west of 

Albuquerque. Ion exchange of calcium and magnesium for 

sodium is the dominant process affecting the ground water. 

Fine-grained sediments, indicated on drillers' and geophysical logs, provide the medium and constituents for the 

exchange process (Anderholm, 1988, p. 101).

GROUND-WATER FLOW SYSTEM

The main components in the water budget in the Albuquerque-Belen Basin are surface-water inflow and outflow in 

the Rio Grande. Inflow is derived from tributary streams, 

ground-water recharge from infiltrating tributary streams, 

mountain-front recharge to ground water, and ground-water 

inflow from the Santo Domingo Basin to the north. Outflow 

includes ground-water outflow to the Socorro Basin to the 

south, withdrawal of ground water from wells, ground-water 

and surface-water discharge to the flood plain of the Rio 

Grande, and evapotranspiration (Kernodle and others, 1987, 

p. 6). The surface-water system consists of the Rio Grande 

and its tributaries, irrigation canals, drainage ditches, and 

water that periodically flows in arroyos or washes, or is 

impounded in flood-retention reservoirs. The Rio Grande is a 

through-flowing river with an average steady-state inflow to 

the basin of 1,150 ft3/s and an average outflow of 924 ft3/s 

from 1948 to 1960. The difference of about 226 ft3/s of 

water was only a part of the water the river lost in its passage through the basin. Also lost from the steady-state surface-water system were average tributary inflows of about 

110 ft3/s for the same period. The majority of this total net 

loss of 336 ft3/s probably was caused by evapotranspiration 

in the flood plain (Kernodle and Scott, 1986, p. 11). However, since 1960 in the Albuquerque area an increasing proportion of evapotranspiration is being captured by the 

ground-water cone of depression associated with groundwater withdrawals (Kernodle and others, 1987, p. 6).
A18 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

Evaporation accounts for a loss of about 5 feet per year in 

areas of exposed water. Evapotranspiration in the flood plain, 

whether from agricultural or riparian vegetation, is about 3 

feet per year. About 0.5 foot of precipitation per year helps 

reduce evapotranspiration, but the net loss for the flood plain 

is estimated to be 428 to 539 ft3/s (J.D. Dewey, Hydrologist, 

U.S. Geological Survey, written commun., 1983). The difference between the flood-plain loss and the surface-water loss 

(336 ft3/s) is made up by loss from ground-water storage 

(Kernodle and others, 1987, p. 8).

The Albuquerque-Belen Basin ground-water system can be 

divided into two subsystems. The first subsystem is in and 

near the area of the Rio Grande flood plain; the second is the 

basin ground-water subsystem adjacent to and under the Rio 

Grande flood-plain subsystem (Kernodle and others, 1987, p. 

8). The first ground-water subsystem (fig. 9) consists of 

ground-water flow within the flood-plain alluvium of the 

river valley, which interconnects the Rio Grande, canals, 

drains, and evapotranspiration. In this subsystem, ground 

water flows because of hydraulic-head differences imposed 

by surface-water bodies, evapotranspiration, and recharge of 

excess irrigation water. Although a large volume of ground 

water moves through the flood-plain alluvium, the hydraulic 

heads and gradient remain unchanged from one year to the 

next, except in the vicinity of increasing ground-water withdrawals. Seasonal hydraulic-head changes seldom exceed 5 

feet (Kernodle and others, 1987, p. 12).

The second basin ground-water subsystem (fig. 9) operates 

outside of, but is hydraulically connected to, the flood-plain 

alluvium. Two forms of ground-water recharge occur outside of the flood plain: (1) tributary recharge from streams 

as they traverse basin fill between the mountains and the 

river; and (2) mountain-front recharge from flows that infiltrate almost immediately after entering the basin from virtually impervious bedrock that encircles the basin-fill deposits. 

Tributary and mountain-front recharge totals about 180 ft3/s 

and maintains high ground-water levels around most of the 

margin of the basin. Ground water then flows downgradient 

toward the axis of the basin, not necessarily toward the Rio 

Grande or its flood plain. As the flow approaches the axis of 

the basin, the flow paths curve and continue southward to the 

lower end of the basin (Kernodle and others, 1987, p. 12).

Ground water flows vertically as well as horizontally. In 

areas of recharge, some ground water moves into deeper 

parts of the aquifer system and follows a generally more 

direct route to the basin's ground-water discharge area. 

Although the shallow ground-water system includes and is 

substantially affected by the flood-plain alluvium of the Rio 

Grande, that effect decreases rapidly with depth (Kernodle 

and others, 1987, p. 12).

Diversion of surface water for irrigation was the earliest 

modification of the natural water system in the AlbuquerqueBelen Basin. Irrigation continued, and the volume of diverted

PRECIPITATION

CROP 

EVAPOTRANSPIRATION

t

PHREATOPHYTE 

EVAPOTRANSPIRATION

I

Rio 

Grande

BASIN GROUND-WATER SUBSYSTEM

PRECIPITATION

MOUNTAINFRONT ALLUVIAL 

RECHARGE / FAN

URBAN 

PUMPAGE

RIO GRANDE

FLOOD-PLAIN

SUBSYSTEM

BASINBOUNDING 

FAULT

Rio Grande

FLOOD-PLAIN ALLUVIUM

BASIN GROUND-WATER SUBSYSTEM 

FIGURE 9. Generalized ground-water subsystems in open basins.

water increased until drains to control waterlogging and salt 

accumulation in the soil became necessary in the 1930's 

(Kernodle and others, 1987, p. 19).

Until the mid-1940's Albuquerque's municipal water needs 

were met by ground-water withdrawals from wells completed 

in the flood-plain alluvium. The effect on the natural water 

system was insignificant in comparison to the effect of irrigation. Dry weather and decreased streamflow in the 1950's 

forced an increased dependence on ground water for irrigation. In addition, Albuquerque's population began to increase 

rapidly and municipal ground-water withdrawals increased. 

Legal regulations imposed in 1959 made construction of 

municipal wells outside of the flood plain increasingly attractive. The area of greatest ground-water stress began to shift 

away from the flood plain. In the area east of the flood plain, 

municipal withdrawals caused a decline in ground-water levels of about 20 feet by 1960 and an additional 60 to 80 feet 

by 1980. Since the 1980's, Albuquerque's municipal water 

needs have been met by ground-water withdrawals matched 

by the purchase and retirement of surface-water rights for 

water removed from the Rio Grande (Kernodle and others, 

1987, p. 19-20).
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A19

150

125

II

O UJ i in 

bo:

100

75

Q CO

Z 3

=30

O Z oc 

O

50

25

ALBUQUERQUE-BELEN. 

BASIN

1900 1910 1920 1930 1940 1950 1960 1970 1980 

YEAR

FIGURE 10. Ground-water withdrawals in the Albuquerque-Belen Basin and in 

the Rio Grande valley, 1907-79. (From Kernodle and others, 1987, fig. 13.)

The trend of total ground-water withdrawals from 1907 to 

1979 in the Albuquerque-Belen Basin and in the Rio Grande 

valley is shown in figure 10. The earliest documented 

ground-water withdrawal began in 1907 within the Rio 

Grande valley. Withdrawal remained at less than 0.17 ft3/s 

until 1932, when the City of Albuquerque constructed the 

Main Plant well field, which supplied all of the city's water 

needs until 1948. The city's rapid population increase after 

the late 1940's necessitated the construction of five new well 

fields from 1948 to 1956. Ground-water withdrawal for all 

uses increased from about 17.3 ft3/s during 1940 to 65.6 ft3/s 

during 1956. Prior to 1956, ground water was produced 

mostly from wells in or near the Rio Grande flood plain 

(Kernodle and others, 1987, p. 20). After 1956, wells were 

constructed east of the Rio Grande valley in response to 

growing demand in that direction. Since about 1970, wells 

have been drilled west of the Rio Grande valley.

Ground-water withdrawal from the area east of the flood 

plain did not become significant until after 1959. The 

increase in ground-water withdrawal in the Albuquerque area 

for 1956-59 and 1976-79 is illustrated in figures 11 and 12, 

respectively.

A seven-layer, three-dimensional ground-water flow model 

was constructed to represent the basin geometry and flow 

system (Kernodle and others, 1987). The grid spacing was 

finer in the Albuquerque area to achieve greater resolution in 

the distribution of stress and observed head response. Six 

model layers represented the upper 6,000 feet of saturated 

basin-fill aquifer, where present. The top layer represented 

the upper 200 feet of saturated thickness. The surface-water 

system in the flood plain of the Rio Grande was assumed to 

maintain a constant hydraulic head in the immediately underlying alluvial deposits.

The initial phase of modeling (Kernodle and Scott, 1986) 

used estimated rates of mountain-front recharge and tributary 

channel losses for ground-water recharge. The process of calibration of the steady-state model was used to refine estimates of hydraulic conductivity and to test the validity of 

assumed boundary conditions (Kernodle and Scott, 1986, p. 

33). The mean absolute difference between measured and 

simulated pre-1961 water levels was 14.6 feet. The second 

phase of the modeling process included the simulation of 

ground-water withdrawals from 1907 to 1979 (Kernodle and 

others, 1987). Because the hydraulic-head data were sparse 

for dates after 1961, the simulation to 1979 was considered 

to be a projection.

Ground-water declines for three simulated aquifer-system 

layers were the response to annual ground-water withdrawals 

in the Albuquerque-Belen Basin. Withdrawals increased from 

about 61.0 ftVs in 1959 to 106 ftVs in 1969. The total 

ground-water withdrawal has continued to increase at a 

nearly constant average rate since 1969 (Kernodle and others, 1987, p. 24). Simulated declines of as much as 60 feet 

are mainly east of and in the Rio Grande valley in the top 

200 feet of the basin-fill aquifer system. In the area influenced by deeper wells drilled east of the Rio Grande valley 

and into the mesa west of the valley, in the layer simulating 

the aquifer from 200 to 600 feet below land surface, simulated declines are as much as 60 feet east of the river and 95 

feet west of the river. Simulated hydraulic-head declines in 

the layer of the aquifer system from 650 to 1,325 feet below 

land surface are about 35 feet east of the river and 5 feet to 

the west. The magnitude of the drawdown is less because of 

fewer wells in this modeled layer, but the areal extent of the 

drawdown has expanded, perhaps reflecting a smaller storage 

value (Kernodle and others, 1987, p. 35).

One of the objectives of the model was to assess the 

effects of ground-water withdrawals on the combined 

ground-water and surface-water system in the Rio Grande 

flood plain (flood-plain system). At any selected time after 

1950 about 25 percent of water withdrawn from the aquifer 

outside of the flood plain is derived from aquifer storage. 

The remaining 75 percent is obtained by depletion of flow in 

the Rio Grande or salvage of evapotranspiration loss, or is 

induced inflow from the Santo Domingo Basin (Kernodle 

and others, 1987, p. 59).

Water budgets for the Albuquerque-Belen Basin are presented in table 5 for 1960-61 and 1976-79. For 1976-79, 68 

percent of all ground-water withdrawals from outside the 

flood plain are supplied by streamflow depletion or salvaged 

evapotranspiration in the flood plain; 25 percent are from 

aquifer storage; and 7 percent are induced ground-water 

underflow from the Santo Domingo Basin. Comparison of 

the two periods indicates an increase in the relative importance of induced flow from the flood-plain systems. Of lesser 

magnitude but also increasing significantly is the proportion 

of induced ground-water flow from the Santo Domingo 

Basin (Kernodle and others, 1987, p. 69).
A20 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

106°45' 106°30'

 700-

350 15'

35°00-

EXPLANATION

Line of equal ground-water withdrawal 

Intervals 100 (0.138), 1,000 (1.38), and 

5,000 (6.91) acre-feet per year per square 

mile (cubic feet per second per square mile)

Eastern 

limit of 

basin-fill 

deposits

5 MILES

I I I I 1 

12345 KILOMETERS

FIGURE 11. Average ground-water withdrawal in the Albuquerque area, 1956-59. (From Kernodle and others, 1987, fig. 14.)
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A21

106°45' 106°30'

35° 15' 

EXPLANATION

Line of equal ground-water withdrawal 

Intervals 100 (0.138), 1,000 (1.38), and 

5,000 (6.91) acre-feet per year per square 

mile (cubic feet per second per square mile)

Eastern 

limit of 

basin-fill 

deposits

SANDOVAL COUNTY

BERNALILLO COUNTY

ALBUQUERQUE

012345 MILES 

|____|____t____l____l____| I I I I I I 

012345 KILOMETERS

FIGURE 12. Average ground-water withdrawal in the Albuquerque area, 1976-79. (From Kernodle and others, 1987, fig. 15.)
A22 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

TABLE 5. Water budget for the Albuquerque-Belen Basin, 1960-61 and 1976-79.

[Modified from Kernodle and others, 1987. All values are in cubic feet per second. Total ground-water withdrawal (64 cubic feet per second for 1960-61,138 cubic feet per second for 1976-79)

has been itemized as to source of withdrawn water. -, not applicable]

1960-61

Budget component

Rio Grande main stem ..................

Rio Grande tributaries...................

(surface flow) 

Ground water ................................

Tributary and mountainfront recharge ..............................

Evapotranspiration ........................

Ground-water withdrawal: 

Intercepted groundInflow

........... 1,152

........... Ill

........... 80

........... 178

Outflow 

or loss

924 

18 

428-539 

30

1976-79

Inflow

1,222 

111

86 

178

Outflow 

or loss

1,040 

18 

428-539 

50

water discharge to

the flood-plain

system 

Induced recharge from

the flood-plain

system 

Induced inflow from

Santo Domingo Basin1 

Depletion in aquifer

storage2

15

3

15

44

10

34

Total 1,521 1,433-1,544 1,597 1,624-1,735

Included also with ground-water inflow. 

2Not included in totals.

SOCORRO AND LA JENCIA BASINS

Anderholm (1987) studied the hydrogeology and 

geochemistry of the Socorro and La Jencia Basins (fig. 1). 

These basins were selected for study because geothermal 

resources in the Socorro Basin could have an influence on 

the ground-water flow system and on the chemistry of 

ground water in the basin. The La Jencia Basin is hydraulically connected to the Socorro Basin and offers a geohydrologic contrast to the Socorro Basin.

HYDROLOGY

Net Rio Grande streamflow depletion from San Acacia to 

San Marcial is about 98 ft3/s annually for 1960-87. There is 

a loss in flow for the Rio Grande in this reach, but at the 

same time a gain in flow occurs in the adjacent conveyance 

channel (Anderholm, 1987, p. 46).

The principal aquifer system in the Socorro and La Jencia 

Basins (fig. 13) is composed of the Quaternary and Tertiary 

Santa Fe Group (Popotosa and Sierra Ladrones Formations)
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A23

SEVILLETA

APPROXIMATE 

J BASIN BOUNDARY

PEDRO z

\ -» ' , BOSQUE DEL APACHE A Carne 

ARMENDARIS> / / ' [ {( / . Colorada. 

NATIONAL WILDLIFE

10 KILOMETERS

FIGURE 13. Cultural and geographic features of the Socorro and La Jencia Basins.
A24 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

and Quaternary deposits. Most wells in Socorro and La Jencia Basins derive water from the Sierra Ladrones Formation. 

The upper part of the Popotosa Formation is a confining unit 

consisting of playa deposits and mudstone. The remainder of 

the Popotosa Formation constitutes the lower part of the 

aquifer system (Anderholm, 1987, p. 18 and 20).

Irrigation in the Rio Grande valley of the Socorro Basin 

was practiced before the 1600's (Yeo, 1928, p. 8). The 

capacity of the irrigation ditches in 1896 was 294 ft3/s and 

the area irrigated was 5,700 acres. In 1928, the capacity of 

the ditches was 331 ft3/s and the total irrigated acreage was 

10,060 acres (Yeo, 1928, p. 9). By the early 1900's about 

40,000 acres of the irrigable land had become waterlogged as 

a result of the infiltration of excess irrigation water (Bloodgood, 1930, p. 48-52). The rising water levels also resulted 

in the concentration of salts near the ground surface.

Ground-water inflow and outflow cannot be calculated 

because information about cross-sectional area, hydraulic 

gradient, and hydraulic conductivity are lacking (Anderholm, 

1987, p. 46). Ground-water inflow occurs from the Albuquerque-Belen Basin north of the Socorro Basin near San 

Acacia, from La Jencia Basin along the west margin of the 

Socorro Basin, and from the Jornada del Muerto Basin along 

the southeast margin of the Socorro Basin. Anderholm 

(1987, p. 55) calculated a water budget for the Socorro Basin 

using ground-water inflow less ground-water outflow as the 

balancing factor in the budget. The budget shows that about 

73 ft3/s is the most probable value for net ground-water 

inflow less ground-water outflow.

Calculated mountain-front recharge for the east side of the 

Socorro Basin is about 2.21 ft3/s using a method documented 

in Hearne and Dewey (1988). Mountain-front recharge for 

the Socorro Peak-Lemitar Mountains is 0.58 ft3/s; one-half of 

this amount is assumed to recharge the Socorro Basin, and 

one-half the La Jencia Basin. Recharge from the Chupadera 

Mountains is about 0.51 ft3/s; one-half is assumed to 

recharge the Socorro Basin and one-half the area between 

the Magdalena and Chupadera Mountains. Total recharge to 

the Socorro Basin is about 2.76 ft3/s (Anderholm, 1987, p. 

49). Ground water flows from La Jencia Basin into the 

Socorro Basin in the Socorro Canyon area. On the basis of 

tritium data, Gross and Wilcox (1981) indicated groundwater flows from La Jencia Basin through the Socorro Peak 

area. The volcanics and Mesozoic and Paleozoic aquifer systems are probably densely fractured near Socorro Peak; thus, 

ground-water flow between basins may be larger in this area 

than in other areas in the Socorro Peak-Lemitar Mountains 

(Anderholm, 1987, p. 25).

Consumptive use in the Socorro Basin includes vegetation 

(both natural and agricultural), evaporation from open water, 

use by rural homesites, and consumptive use by municipalities. Consumptive use in the basin is about 173.0 ft3/s 

(Anderholm, 1987, p. 51 and table 9).

A water budget for the Socorro Basin was developed. 

Because of lack of confidence in the estimates, most probable values for each major factor in the water budget were 

presented. The water budget can be represented by the following equation:

= «2si - 6so) + - Qcu + Qr (3)

where AS = change in ground-water storage, in ft3/s; 

Qsi = surface-water inflow, in L3/T; 

Qso = surface-water outflow, in L3/T; 

ggi = ground-water inflow, in L3/T; 

Qgo ~ ground-water outflow, in L3/T; 

Qcu = consumptive use, in L3/T; and 

QT = recharge, in L3/T.

Assuming no change in storage (AS = 0), equation 3 can 

be rearranged so that the ground-water inflow and outflow 

terms are isolated.

(fid - 6eo) = Qcu - (Qsi - Cso) - Qr (4)

and

(73 ft3/s) = 173 ft3/s - (97 ft3/s) -3 ft3/s (Anderholm, 

1987, p. 54).

GEOCHEMISTRY

Ground-water quality in the Socorro Basin east of the Rio 

Grande valley is controlled by the mineralogy of the local 

Mesozoic and Paleozoic rocks. Dissolution of calcite, gypsum, and dolomite is reported to be the major factor controlling water chemistry. Ground water contains large percentages 

of calcium, magnesium, and sulfate (Anderholm, 1987, p. 56).

Three zones of differing water quality exist in the Rio 

Grande valley. In the northern part of the valley the water 

has chloride concentrations as great as 4,020 mg/L. The 

source of the chloride in the northern part of the basin probably is upward-flowing ground water entering from the southern Albuquerque-Belen Basin. Near Socorro, irrigation-return 

flow and inflow from basin margins probably control water 

quality. Chloride concentrations are 100 mg/L or less. South 

of Socorro, ground-water chloride concentrations are as great 

as 1,100 mg/L. These large concentrations could result from 

a constriction to upward-flowing deep-basin ground water 

with a large concentration of chloride, leakage of geothermal 

water upward along a lineament, or both (Anderholm, 1987, 

p. 56-57 and pi. 4).

In La Jencia Basin, ground water contains mostly calcium, 

sodium, and bicarbonate. In the principal recharge area, east 

of the basin, water is a calcium bicarbonate type. The increase 

of sodium, downgradient from the recharge area, probably is 

caused by exchange of calcium for sodium on clays in the 

aquifer system. Generally, ground water has a chloride concentration of less than 30 mg/L (Anderholm, 1987, pi. 4).
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A25

MESILLA BASIN

The Mesilla Basin is in south-central New Mexico and a 

small part of western Texas (north of El Paso), and Mexico 

(fig. 1). Only the part of the Mesilla Basin that lies within 

the United States will be discussed in this report. This basin 

was selected for detailed study because agriculture is a large 

user of surface water and ground water. A growing population in Las Cruces, New Mexico, and El Paso, Texas (fig. 

14), requires increasing withdrawals of ground water. Sufficient data were available to simulate the surface-water/ 

ground-water interaction in the flood plain of the Rio Grande 

by incorporating and routing flows in drains, canals, and the 

river into a ground-water flow model of the basin that will be 

described later.

GEOLOGY

The Mesilla Basin contains flood-plain alluvium along the 

Rio Grande and predominantly fluvial deposits of the Santa 

Fe Group outside and beneath the flood plain (Wilson and 

others, 1981). The flood-plain alluvium is 60 to 80 feet thick 

with a 30- to 40-foot basal layer of gravel overlain by sand, 

gravel, and clay.

The fluvial facies of the Santa Fe Group represent 

through-flowing Rio Grande deposition. The deposits are 

predominantly sand with layers of gravel, silt, clay, and 

sandy clay. A thick sequence of clay and sandy clay is 

reported on the east side of the valley from the Texas border 

north for about 15 miles (Wilson and others, 1981, p. 39). A 

zone indicative of an eolian depositional environment is 

found in a well field a few miles north of Canutillo, Texas. 

These deposits are uniform, fine-grained brown sand with little or no clay in the interval from 600 to 1,100 feet below 

land surface.

Saturated basin-fill sediments with more than 50 percent 

sand, gravel, cobbles, and boulders are prevalent in the 

northern half of the Rio Grande valley within the Mesilla 

Basin, especially in the Las Cruces area and along the east 

side of the valley as far south as Vado (fig. 15). In the southern half of the basin, this lithology occurs in the Canutillo 

area, which contains a sandy deep aquifer of possible eolian 

origin, also on the west side of the basin. Sediments that 

consist of more than 50 percent clay, silt, mudstone, shale, or 

caliche are most prevalent on the mesa west of the Rio 

Grande and south of the New Mexico-Texas State line.

Sand and gravel are most common to a depth of 400 feet 

below the water table. From 400 to 1,400 feet below the 

water table, sand and gravel sediments are most common; 

silt and clay are the second most common type. Sand and

gravel in the Las Cruces area, possibly fluvial and alluvialfan deposits, are present at greater depths.

The average thickness of Neogene sediments is about 2,400 

feet (Birch, 1980b, p. 18). The sediments are less than 1,600 

feet thick along the Mexican border (Birch, 1980b, p. 12). The 

greatest thickness of Neogene sediments is southwest of Las 

Cruces. The thickness of the Paleozoic and Mesozoic rocks is 

greater toward the southern end of the basin.

GEOCHEMISTRY

Anderholm (1992) described major factors controlling 

ground-water quality in the Mesilla Basin according to areas 

defined by Wilson and others (1981) that display common 

water-quality characteristics. Ground water flowing in from 

the northwest has a specific conductance of 1,400 to 2,310 

microsiemens; sulfate and sodium are the predominant ions 

(Anderholm, 1992, p. C65). Along the southwest part of the 

basin margin, sodium bicarbonate type water has a specific 

conductance of less than 1,940 microsiemens, and a sodium 

chloride type water has a specific conductance of about 

7,400 microsiemens (Anderholm, 1992, p. C65). The sodium 

chloride water may be either geothermal water or water that 

flows upward along a major fault on the southwest side of 

the basin. Sulfate is the dominant anion in ground water west 

of Las Cruces; specific conductance generally is less than 

900 microsiemens. Ground-water chemistry in the Rio 

Grande flood plain varies vertically and horizontally. This 

variation is due to mixing of excess applied irrigation water 

from the river with water in the basin-fill aquifer system. 

Shallow ground water generally has greater specific conductance than deeper water because of greater dissolved-solids 

concentrations in irrigation-return flow. In the northeastern 

part of the basin, water associated with Mesozoic and Paleozoic rocks north and east of Las Cruces has a larger percentage of sulfate and chloride anions and a greater specific 

conductance than water associated with volcanic rocks east 

of Las Cruces.

Geothermal or upward-flowing deep-basin water results in 

water with large concentrations of dissolved solids in several 

parts of the basin. On the eastern side of the basin, geothermal water with large concentrations of chloride, silica, and 

potassium mixes with cooler, less mineralized water in the 

basin-fill aquifer system. Near Radium Springs, a Known 

Geothermal Resource Area, ground water containing a large 

concentration of chloride is found. In the southeastern corner 

of the basin, water containing large concentrations of chloride is attributed to upward flow of water from deep circulation within the basin.
A26 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

107°00' 106°30'

32°30- 

O 

I'

3

32°00'

SIERRA 

DELAS 

UVAS

ROBLEDO s; jLaieburg 

MTS

/

SLEEPING 

LADY HILLS

WEST 

MESA

V 

\

- 

\

/

OCo

^ "V

(^ } *RILEY /

r

\S"'

\ UNITED STATES / ___ i ___ ___ ___ ___ ___ ^-~^

MEXICO

5 10 MILES 

_l______I I 

10 KILOMETERS

EXPLANATION

Mesilla Valley 

 Approximate basin boundary

FIGURE 14. Cultural and geographic features of the Mesilla Basin north of the United States-Mexico international boundary.
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A27

107°00- 106030'

32°30- 

< | <

'§ 

Q

32°00'

Radium 

Springs

SIERRA 

DELAS 

UVAS

DONA 

ANA 

MTS \

I

\

i

SLEEPING 

LADY HILLS

\ %^

\

ITORTUGAS 

MTN

\ BISHOP CAP 

i MTN

^ \ FILLMORE

PASS

UNITED STATES 

MEXICO

10 MILES

10 KILOMETERS

\

-rv V

\

1-

NEW MEXICO -

TEXAS

MT

LT/ \

^ g. ^.

m

\I UNITED STATES ; ___ i ___ ___ ___ ___

EXPLANATION

Mesilla Valley

More than 50 percent clay, 

silt, mudstone, shale, or 

caliche

More than 50 percent sand, 

gravel, cobbles, or boulders

Areas where data are not 

available

Approximate basin boundary

FIGURE 15. Lithologic zones in the Mesilla Basin north of the United States-Mexico international boundary.
A28 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

GROUND-WATER FLOW SYSTEM

Frenzel and Kaehler (1992) discussed the basin flow system. Figure 16 is a schematic diagram showing the following 

ground-water/surface-water interactions in the Mesilla Basin:

(1) (a) Net diversions (gross diversions less water 

returned directly from the irrigation system to the river 

or drains); (b) effective rainfall on both irrigated and nonirrigated lands (that part of rainfall that either recharges 

aquifers or reduces the volume of ground water that 

would be discharged); (c) evaporation from canal surfaces; and (d) evapotranspiration from irrigated lands, 

are summed to provide an overall flux for the valley area 

(fig. 17). This summation, termed "net irrigation flux," 

includes, by implication, (e) leakage from irrigation 

canals to ground water and that part of irrigation groundwater pumpage recirculated back to ground water.

(2) Seepage to and from the river and drains, including 

evapotranspiration from river and drains.

(3) Evapotranspiration from nonirrigated lands.

(4) Water pumped from wells for municipal, industrial, 

and domestic purposes. Also included in this group are 

septic-system return flows.

(5) Mountain-front recharge (drainage areas underlain by 

bedrock with incised ephemeral streams) and slope-front 

recharge (drainage areas underlain by basin fill).

(6) Underflow.

The discharge of the Rio Grande in the Mesilla Valley is 

regulated by releases of water from Caballo Reservoir that in 

turn are replaced by releases from Elephant Butte Reservoir 

north of the study area. Depletions (the flow passing Leasburg less the flow passing El Paso Narrows) averaged 305 

ft3/s during 1930-75 (Frenzel and Kaehler, 1992, p. C8-C9).

Drains have been constructed to keep the water table 

below the level of irrigated fields in the Mesilla Basin. By 

1917 the need for drains arose because irrigated acreage had 

nearly doubled during the previous 10 years (Conover, 1954, 

p. 53-56). By the summer of 1919, about 75 miles of drains 

existed (Conover, 1954, pi. 6). The average drain discharge 

for 1923-50 was 1.4 ft3/s per mile of drain. Drain discharges 

have been variable and intermittent since 1950, due to a 

lower water table (Frenzel and Kaehler, 1992, p. C9). 

Ground water is discharged to drains when ground-water levels rise above drain bottoms and drainwater eventually flows 

back to the Rio Grande. During periods of drought, the limited surface-water supply is supplemented by ground-water 

withdrawals and drain discharge is decreased (King and others, 1971, p. 57).

Evaporation from canal surfaces and drains was estimated 

to be 11.1 ft3/s. Evaporation from the river channel was estimated to be 16.6 ft3/s (Frenzel and Kaehler, 1992 p. C9).

Ground-water recharge occurs predominantly on the east 

side of the basin and along ephemeral stream channels.

Recharge also takes place when excess irrigation water percolates through the flood-plain alluvium. Total recharge to 

the basin is about 15.3 ft3/s (Frenzel and Kaehler, 1992, p. 

C23). After long periods of heavy pumping, ground-water 

levels rapidly recover when surface water is applied on agricultural lands (Taylor, 1967).

The general direction of ground-water flow in the Mesilla 

Basin is southeastward. Ground water probably moves southward away from the Mesilla Valley near Las Cruces and back 

toward the valley in the southern part of the basin. Ground 

water probably also moves vertically downward from the valley in the north. Upward movement of water in the southern 

part of the valley was indicated by increasing hydraulic head 

with depth (Leggat and others, 1962, p. 16).

The water-table gradient beneath the West Mesa averages 

about 4.5 feet per mile, approximately the same as in the 

Mesilla Valley. Near the margins of the Mesilla Basin, water 

flows into the basin from the surrounding highlands. The 

water-table gradient is steeper along the margins due to 

reduced aquifer transmissivity caused by less aquifer thickness and possibly smaller permeability (Frenzel and Kaehler, 

1992, p. CIS).

Ground-water withdrawals for municipal, domestic, and 

industrial uses increased from about 6 ft3/s in 1950 to about 

60 ft3/s in the early 1970's. About one-half of this amount was 

withdrawn by the city of El Paso; about one-fourth was withdrawn by the city of Las Cruces. The remaining one-fourth 

was withdrawn by small towns, villages, and industries (Frenzel and Kaehler, 1992, p. C21). About 227,000 acre-feet of 

water has been removed from storage in the basin.

Most flow to and from the ground-water system in the valley fluctuates seasonally. Flow in the intermediate term, 1 to 

5 years, fluctuates with the availability of surface water. 

Over the long term, flow to or from the ground-water body 

does not fluctuate much at all. Change in ground-water storage due to ground-water withdrawals for irrigation occurs 

only when net irrigation flux (fig. 17, line E) falls below 

zero, as occurred during the mid-1950's and early 1960's. 

When irrigation flux is above zero, drains maintain a constant water table in the central basin.

Frenzel and Kaehler (1992) completed a three-dimensional, finite-difference ground-water flow model of the 

Mesilla Basin. The model simulated the entire thickness 

(3,800 feet) of basin fill using five model layers; the uppermost layer of the model represented the top 200 feet of 

unconfined aquifer. The boundaries of the model were 

defined by the location of basin-bounding faults on the east 

and west and by shallow bedrock on the north and south. 

The model grid was constructed with the smallest cell size 

along the flood plain of the Rio Grande. Input hydraulic conductivity decreased with depth to simulate compaction of 

aquifer material. The simulated mass balance for the initial 

condition (pre-1915) and for the end of the simulated time 

(1975) is shown in table 6.
RIVER SUMMATION = DEPLETION

EVAPOTRANSPIRATION 

FROM RIVER AND 

DRAINS ,

EVAPOTRANSPIRATION

FROM IRRIGATED LAND

(INCLUDES IRRIGATION

WITHDRAWALS THAT

ARE NOT RECIRCULATED)

1b

LAS CRUCES SEWAGE

TREATMENT PLANT 

EFFLUENT 4

MOUNTAIN AND

SLOPE-FRONT

RECHARGE

SHALLOW GROUND WATER

DEEP GROUND WATER

EVAPO

OR T

WATER 

FIGURE 16. Interactions between ground water and surface water in the Mesilla Basin. (Modified from Frenzel and Kaehler, 1992, fig. 
A30 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

From the simulation, about 80 percent of all ground water 

withdrawn for nonirrigation purposes was derived either from 

induced infiltration of surface water or capture of natural 

ground-water discharge to the surface-water system, 10 percent was from aquifer storage, and the remaining 10 percent 

was from salvaged evapotranspiration. These percentages 

remained essentially unchanged for a test of the model's 

response to a range of aquifer diffusivity (transmissivity 

divided by storage coefficient) from one-quarter to four times 

the diffusivity of the calibrated model. Ground-water withdrawals of 50 ft3/s for 1941-75 first were simulated as a line 

of wells parallel to and just west of the flood plain and then as 

a line of wells parallel to but 12 to 14 miles west of the river. 

For the line of wells simulated near the flood plain, the 

sources of withdrawn water remained in the same proportion 

as for the historical simulation; 80 percent of withdrawals 

were from streamflow depletion, and changes in diffusivity 

had little effect. For the line of wells simulated 12 to 14 miles 

from the flood plain, streamflow depletion was 53 percent of 

the total withdrawal for the large diffusivity, 15 percent for the 

calibrated model, and 3 percent for the small diffusivity.

MIMBRES BASIN GEOLOGY

The Mimbres Basin in southwestern New Mexico (fig. 1) 

is a closed basin into which several intermittent streams flow. 

The Mimbres Basin was selected for a lithologic study 

because development of ground-water resources for irrigation 

made many drillers' logs available for the analysis.

Analyses of drillers' logs show that total saturated sediments penetrated by wells in the central part of the basin 

contain a mixture of sediment types. The extreme northwest 

corner of the basin contains sediments identified as conglomerate on drillers' logs (fig. 18). Areas of clay and silt are 

present principally near Deming, extending east and west, 

and in the Columbus area.

Wells primarily penetrate conglomerate in the first 200 

feet of saturated sediments in the upper reaches of the Mimbres River and San Vicente Arroyo. The central part of the 

basin is composed predominantly of clay and silt. In the 

depth interval between 200 and 400 feet below the water 

table, conglomerate becomes more common than at shallower depths, except in the central part of the basin. 

Although data are sparse, the 400- to 1,000-foot depth interval in the northwest corner of the basin is composed of 

poorly sorted sediments; clay and silt predominate in the 

central part of the basin.

On the basis of gravity data, Birch (1980b, p. 12) concluded that the thinning of sediments along the international 

boundary is similar to that found in the Mesilla Basin. Average thickness of sediments in the Mimbres Basin is about 

1,570 feet. The gap between the East and West Potrillo 

Mountains is estimated to be about 6 miles wide and 1,640 

feet deep and may provide a hydraulic connection between 

the Mesilla and Mimbres Basins.

800

600

O 400 tten

200 -

< in D uZ O

-200

-400

1910 1920 1930 1940 1950 1960 1970 1980

EXPLANATION

Net diversion minus estimated evaporation 

from canals of 5.5 cubic feet per second

_ _ _ B_ _ _ Effective rainfall on irrigated lands

_ _ C_ _ Effective rainfall on other lands

_ D _ Estimated evapotranspiration from irrigated lands

E Summation of A, B, C, and D ("net irrigation flux")

FIGURE 17. Estimate of net irrigation flux in the Mesilla Valley, 1915-75. 

(From Frenzel and Kaehler, 1992, fig. 16.)

SUMMARY OF REGIONAL ANALYSES

Regional analyses also were conducted as part of the 

SWAB study. Aquifer characteristics, water chemistry, and 

various hydrologic topics are described for the complete 

study area in the remainder of this report.

LITHOLOGIC ANALYSES

Lithologic trends with depth in the Albuquerque-Belen, 

Mesilla, and Mimbres Basins are shown in table 7. The lithologic categories are defined by Kaehler (1990, fig. 4). For the 

Albuquerque-Belen and Mesilla Basins, the lithologic category for the total saturated thickness in each well for which 

a lithologic analysis was completed is most commonly a 

mixture of sand and gravel (category 5), particularly in the 

upper 600 feet. The second most common category for both 

basins is predominantly clay and silt (category 1). Generally, 

sand and gravel (category 5) are slightly more common than 

clay and silt at depths greater than 600 feet in the Mesilla 

Basin (table 7). In the Mimbres Basin, clay and silt (category 

1) are common in most saturated depth intervals, except for
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A31

TABLE 6 Simulated mass balance for the Mesilla Basin, pre-1915 and 1975.

[From Frenzel and Kachlcr, 1990, p. 87. All values are in cubic feel per second]

Source

Initial 

condition

End 

of

simulation 

(1975)

Inflow from: 

Net river seepage............................................... 320.9

Net irrigation flux............................................. .00

Mountain- and slopefront recharge.................................................. 14.95

Underflow in floodplain alluvium................................................. . 16

Outflow to:

Net drain seepage.............................................. .00

Net nonirrigation 

pumpage.......................................................... .00

Evapotranspiration 

from nonirrigated 

lands................................................................ -335.82

Underflow in floodplain alluvium................................................. -.09

Net flow to storage...............................................___.00

Difference............................................................ .12

Percent difference................................................ .04

76.58

258.83

15.89

.95

-180.48

-56.73

-112.28 

-.72

-1.86

.18 

.05

the 200- to 400-foot and 800- to 900-foot depth intervals in 

which conglomerate (category 3) is more common. The second most common category is a mixture of clay, silt, sand, 

and gravel sediments (category 2). The Mimbres Basin contains a significantly larger percentage of conglomerate (category 3) than the other two basins (table 7).

Similarities and differences in the lithologic data reflect 

the geologic setting and depositional history of the basins. 

Predominantly coarse grained sediments in approximately 

the upper 400 to 600 feet of saturated thickness in the Albuquerque-Belen and Mesilla Basins probably were deposited 

by the relatively high energy, ancestral Rio Grande. This 

depositional mechanism probably contributed to the general 

trend of coarse material near the northern end of each basin 

and fine-grained material toward the southern end.

The Mimbres Basin probably has remained a closed basin 

throughout its depositional history. Coarse, cemented older 

sediments common in the northern part of the Mimbres Basin

were derived from local uplifts; these sediments currently are 

near the surface because of subsequent tectonic activity.

Lithologic data in the Albuquerque-Belen Basin and primarily in the southern parts of the Mesilla and Mimbres 

Basins indicate fine-grained sediments probably of lake or 

playa origin. All three basins were topographically closed 

during deposition of these older deposits. The ancestral Rio 

Grande probably emptied into a lake or playa in the southern 

part of the Mesilla and Mimbres Basins during much of this 

early depositional history.

POTENTIOMETRIC SURFACE

The potentiometric surface in the basin-fill aquifer system 

of the study area is shown in figure 19. The contours are 

based on water-level data resulting from measurements made 

in November through March during 1972-81. All wells used 

in the compilation of the map are completed in alluvial
A32 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

17 R16W MEXICO 2

20 KILOMETERS

EXPLANATION

More than 50 percent clay, silt, 

mudstone, shale, or caliche

Between 20 and 50 percent clay, silt, 

mudstone, shale or caliche; less than 70 

percent sand, gravel, cobbles or boulders; 

and less than 70 percent sandstone, 

conglomerate, limestone, or volcanics

Less than 20 percent clay, silt, mudstone, 

shale, or caliche; less than 70 percent 

sandstone, conglomerate, limestone, or 

volcanics; and less than 70 percent sand, 

gravel, cobbles, or boulders

Greater than 70 percent sandstone, 

conglomerate, limestone, or 

volcanics

\' ,' ', \ Areas where data are not available 

 Approximate basin boundary 

FIGURE 18. Lithologic zones in the Mimbres Basin.
TABLE 7. Percentage of wells in each lithologic category, by saturated interval, Albuquerque-Belen, Mesilla, and Mimbres Basins. 

[Calculation of average percentage excludes total interval percentage. Percentages may not add to 100 percent due to rounding. Categories from Kaehler, 1990, fig. 4]

Lithologic category

(More than 50 percent 

clay, silt, mudstone, 

shale, or caliche)

Saturated

interval

(feet)

0-100

100-200

200-300 

300-400 

400-500

500-600600-700 700-800 

800-900 

900-1,000

1,000-1,100

1,100-1,200 

1,200-1,3001,300-1,400

1,400-1,500

Total

interval

Average

percentage

AlbuquerqueBelenBasin

23.0

27.8

28.4 

25.0 

20.4

28.629.4 

41.7 40.0 

28.6

50.0

45.5

22.2

44.4

50.0

20.533.7

Mesilla

Basin

14.4

23.321.3 

22.2 

38.334.932.5 

26.7 25.0 

32.430.0

21.1 25.022.2

33.3

14.3

26.8

MimbresBasin

41.043.6

26.9 

20.5 50.0

47.1

38.5 33.3 

25.0 

40.0

33.333.3 

50.0

50.0

50.039.3

38.8

(Between 20 and 50 

percent clay, mudstone, 

shale, or caliche; 

less than 70 percent 

sandstone, conglomerate, 

limestone, or volcanics; 

and less than 70 percent 

sand, gravel, cobbles, 

or boulders)

AlbuquerqueBelen

Basin

27.823.7

19.4 

18.3 

27.8

28.635.3 25.0 33.3 28.6

8.3

27.3 

44.4

0.0

0.0

39.423.2

Mesilla

Basin

26.126.728.6 25.9 

19.2

23.3

12.5 

16.7 12.5 

22.0

30.031.6 25.0

22.2

33.3

42.0

23.7

MimbresBasin

21.3

13.8

25.4 25.0 

10.7

5.9

15.4 

22.2 

12.5 

0.0

66.7

33.3 

50.050.0

0.0

28.223.5

(More than 70 percent 

sandstone, conglomerate, 

limestone, or volcanics)

AlbuquerqueBelenBasin

4.8

5.2

3.0 5.0 5.6

2.4

2.9 

0.0 0.0 7.10.00.0 0.0

11.112.5

1.6

4.0

Mesilla

Basin

0.92.22.9 

3.7 

4.3

2.3

7.5 

3.3 

4.2 

8.7

5.0

10.5 

8.3

11.1

11.1

0.95.7

Mimbres

Basin

18.8

24.528.4 29.6 25.029.4

30.8 33.3 

50.0 40.0

0.0

33.3 

0.00.0

0.0

18.8

22.9

(Less than 20 percent 

clay, silt, mudstone, 

shale, or caliche; 

less than 70 percent 

sandstone, conglomerate, 

limestone, or volcanics; 

and less than 70 percent 

sand, gravel, cobbles, 

or boulders)

AlbuquerqueBelenBasin

5.63.17.5 6.7 0.0

4.8

8.8 

0.0 

0.0 0.00.00.0 0.0

11.1

12.5

8.7

4.0

Mesilla

Basin

1.81.11.4 

3.7 

2.1

4.7

0.0 6.7 

4.2 4.30.05.3 0.00.0

0.02.72.3

MimbresBasin

3.4

9.6

11.9 

11.4 

3.6

11.8

0.0 0.0 0.0 0.00.0

0.0 0.00.0

50.0

9.46.8

(More than 70 

percent sand, 

gravel, cobbles, 

or boulders)

AlbuquerqueBelenBasin

38.939.2

41.8 

45.0 46.2

35.723.5 

33.3 

26.7 

35.7

41.7

27.3 

33.3

33.3

25.029.935.1

Mesilla

Basin

56.8

46.745.6 

44.4 

36.234.9

47.5 

46.7 

54.2 

32.435.031.6 

41.744.4

22.2

40.241.3

MimbresBasin

15.4

8.5

7.5 

13.6 10.7

5.9

15.4 11.1 12.5 

20.0

0.00.0 0.00.0

0.0

4.3

8.0

SOUTHWEST ALLUVIAL

00«Z

Z

<*

IEXICO /

,** aADJACENT1on
A34 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

COLORADO 

1 NEW MEXICO 

<:

EXPLANATION

Area of alluvial fill

Potentiometric contour Shows 

altitude at which water level 

would have stood in tightly 

cased wells. 1972-81. Dashed 

where approximately located. 

Contour interval 200 feet. 

Datum is sea level

FIGURE 19 Potentiometric surface in the basin-fill aquifer system, 1972-81. (Modified from Wilkins, 1986b, fig. 67.)
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A35

deposits. Water levels in the selected wells represent static 

head at many levels in the aquifer system. The sparse data on 

well depth and perforated interval prevented development of 

potentiometric-surface contours for specific depth intervals in 

the basin-fill aquifer system.

Potentiometric-surface contours were drawn on the basis 

of the assumption of hydraulic continuity between basin 

aquifers. This assumption appears to be justified from the 

continuity of measured water-level altitudes near some basin 

boundaries and the continuity of alluvial sediments between 

basins. Although the regional aquifer system can be considered unconfined, areas with confined conditions have been 

identified. Most notable of these areas of confinement are 

part of the San Luis Valley, Colorado, and an area around El 

Paso, Texas. There are also several small areas along the Rio 

Grande. The contours, as drawn, do not differentiate between 

confined and unconfined conditions.

Parts of the water table in the basin-fill aquifer system are 

not contoured. These areas lack sufficient data during the 

1972-81 period to define the potentiometric surface. Additionally, contours have not been extended across areas where 

alluvium is missing. It is recognized that there are areas 

where sediments of the Santa Fe Group may be capped by 

volcanic rocks. In these places, there probably is hydraulic 

continuity between adjacent alluvial sediments and sediments 

underlying the volcanic-capped areas, but data generally are 

lacking to define the potentiometric surface. The area west of 

the Rio Grande between the Colorado-New Mexico State 

line and Embudo, New Mexico, and the mesa between Santa 

Fe and the Albuquerque-Belen Basin are two such areas. 

Contours within basins adjacent to the United States-Mexico 

boundary have not been extended into Mexico because of 

lack of data. It is recognized that these basins do not terminate at the boundary and that hydraulic continuity does exist.

Contours of the potentiometric surface indicate areas of 

ground-water recharge and discharge, direction of flow, and 

the gaining and losing reaches of streams. Throughout much 

of the study area, contours indicate that the Rio Grande flood 

plain gains water from the basin-fill aquifer system; the river 

acts as a drain. Locally, however, the river may supply water 

to the ground-water reservoir or may not be in hydraulic 

connection with the basin-fill aquifer system.

The topography in the Rio Grande rift relates to the graben structure where valleys are bounded by uplifted areas on 

the sides; potentiometric contours show that the aquifer is 

recharged from the highland areas where precipitation is 

greater. Closed surface-water basins in southwestern New 

Mexico display this same characteristic. In general, groundwater movement in the study area is from the west and east 

to the center of the valleys and then southward. However, 

ground-water movement in the Animas and Playas Basins in 

southwestern New Mexico is northward to the Gila River.

GROUND-WATER CHEMISTRY

Primary chemical processes that occur in ground water in 

the study area are dissolution of calcite, dolomite, gypsum, 

and halite; exchange of calcium for sodium; precipitation of 

calcite and dolomite; and mixing of water in the flow system. 

Dissolution, ion exchange, and precipitation largely are 

dependent on the presence of specific minerals and lithologies in the surrounding bedrock and basin-fill sediments. 

Mixing of water in the flow system depends on flow patterns 

that allow waters from different sources with different chemical compositions to combine.

The following descriptions of water temperature, specific 

conductance, and chemical water types provide an overview 

of the study area. Because the data are from wells completed at a variety of depths in the basin fill, the descriptions 

are generalized and may not apply to water at a specific 

depth interval. Wells generally are completed as shallow as 

possible and data usually represent the upper part of the 

basin-fill aquifer system.

TEMPERATURE

Ground-water temperature can be affected by recent volcanic activity, by faulting resulting in deep circulation of ground 

water, and by the local flow system. Generally, the temperature of ground water (fig. 20) from the San Luis Basin south 

to the northern end of the Albuquerque-Belen Basin ranges 

from 5 to 15 degrees Celsius. Farther south the temperature 

generally ranges from 15.1 to 25 degrees Celsius.

Small areas scattered throughout the study area have 

ground water with temperatures ranging from 25.1 to 35 

degrees Celsius. These areas are associated with Quaternary 

and Tertiary volcanic rocks (fig. 3) that have retained heat 

associated with their formation and have transmitted the heat 

to the ground water. Another explanation for elevated 

ground-water temperatures is an increased temperature gradient associated with ground-water discharge sites (Freeze and 

Cherry, 1979, p. 509) within the Rio Grande flood plain. 

Faulting within the rift is common in the study area and is 

associated with warm water in the Socorro and Mesilla 

Basins (Anderholm, 1987, 1990).

SPECIFIC CONDUCTANCE

Specific conductance of ground water is related to geologic, hydrologic, topographic, and climatic factors. The type 

and occurrence of minerals in the bedrock and in sediments 

within the basin, through which ground water moves (in turn, 

dependent on the sequence and arrangement of geologic 

units), are important factors. Evapotranspiration rates, prior
A36 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

109" 108° 107°

EXPLANATION

Ground-water temperature, 

in degrees Celsius

| | 5 to 15

15.1 to 25 

25.1 to 35

MONTROSE ' j

-COURAY!_ V FPUEBLO

CUSTER

COLORADO 

NEW MEXICO"

FIGURE 20. Ground-water temperatures in the basin-fill aquifer system.
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A37

use of the water, location of the water in the flow system 

relative to recharge and discharge areas, and length of time 

the water has been resident in the flow system also are 

important. The distribution of various ranges of specific conductance of ground water in the basin-fill aquifer system is 

shown in figure 21. Four specific-conductance categories 

were selected on the basis of drinking water standards and 

crop tolerance to salinity. The category of 0 to 750 microsiemens is approximately equal to 0 to 500 mg/L dissolved solids and generally is recommended for human consumption 

(U.S. Environmental Protection Agency, 1986). The upper 

limit of the category, 751 to 2,250 microsiemens, is the 

upper limit of a high salinity hazard for irrigated crops. The 

category of 2,251 to 5,000 microsiemens corresponds to the 

very high salinity hazard (U.S. Salinity Laboratory Staff, 

1954). The fourth category is specific conductance greater 

than 5,000 microsiemens.

In areas where specific-conductance data were not available, the predominant specific conductance in the surrounding area was assumed to exist. Small zones having a 

different specific conductance than the surrounding area were 

delineated only where data from more than one well and the 

scale of the map permitted delineation. Wells in these small 

areas may be producing water from different zones than 

wells in the adjacent larger area.

The San Luis and Espanola Basins and basins in southwestern New Mexico (fig. 1) generally have water with specific conductance in the range of 0 to 750 microsiemens. 

Basins south of the Espanola Basin along and east of the Rio 

Grande generally have water with specific conductance in the 

range of 751 to 2,250 microsiemens. Specific conductance of 

water in basins in west Texas is variable.

Within the closed-basin part of the San Luis Basin north of 

the Rio Grande (figs. 1, 2), there are areas where specific 

conductance of water ranges from 751 to 5,000 microsiemens 

(fig. 21). Depth to water in these areas is less than 20 feet 

(Crouch, 1985). Estimated evapotranspiration rates range 

from 0 to 4.5 acre-feet per year in the basin, depending, in 

part, on the depth to the water table (Hearne and Dewey, 

1988, p. 40). Concentration of salts by evapotranspiration may 

account for the increased specific conductance. The areas with 

increased specific conductance north of the Rio Grande also 

correspond in a general way to areas with increased groundwater temperature (fig. 20). Higher temperature allows more 

solute to be dissolved in a given volume of water.

In the San Luis Basin south of the Rio Grande, the area 

in which ground water has specific conductance greater than 

750 microsiemens corresponds to the area where water temperature ranges from 15.1 to 25 degrees Celsius (fig. 20). 

This area lies between major faults in the basin (Wilkins, 

1986a, pi. 2). These faults may allow water with increased

specific conductance and temperature to flow upward and 

mix with shallow ground water. The area also is a discharge 

area (Crouch, 1985).

The southern part of the Santo Domingo Basin and the 

northern part of the Albuquerque-Belen Basin have areas 

where water has specific conductance greater than 750 microSiemens. The area along and north of the Jemez River on the 

western side of the basins has water temperatures in the range 

of 15.1 to 25 degrees Celsius (fig. 20). The specific conductance of Jemez River water is more than 1,200 microsiemens 

and recharge to the basin fill from the Jemez River is reported 

to be 34.5 ft3/s (Anderholm, 1988, p. 24). Mesozoic and Paleozoic rocks on the eastern basin boundary (fig. 3) are a source 

of soluble minerals that may cause increased specific conductance. Ground-water flow is from the north and east into the 

area of increased specific conductance. To the west, the Jemez 

Mountains consist of a volcanic complex and are a recharge 

area where increased ground-water temperatures and larger 

concentrations of dissolved constituents are found. Ground 

water in the Jemez geothermal reservoir in the Jemez Mountains contains dissolved-silica and dissolved-chloride concentrations of about 100 and 1,500 mg/L, respectively.

On the western side of the Albuquerque-Belen Basin south 

of the Jemez River, the specific conductance of water generally is greater than 750 microsiemens. Mesozoic rocks west 

of the alluvial material in the study area (fig. 3) are a source 

of soluble minerals as well as a recharge area for the basin. 

Anderholm (1988, p. 67) reported that specific conductance 

of water in the Mesozoic rocks is generally less than 10,000 

microsiemens. As water moves downgradient from the Mesozoic rocks into the alluvial deposits, to the east, specific conductance decreases due to mixing of the large conductance 

water with water of lesser specific conductance. In the southwestern part of the basin, specific conductance is influenced 

by ground water flowing from volcanic rocks south and west 

of the basin and by inflow from La Jencia Basin. Ground 

water from La Jencia Basin has a specific conductance less 

than 750 microsiemens. In the south-central part of the Albuquerque-Belen Basin, specific conductance is in the range of 

2,251 to 5,000 microsiemens, probably as a result of water 

with specific conductance greater than 5,000 microsiemens 

flowing from the north.

South of the Albuquerque-Belen Basin, the influence of 

geology on specific conductance is more apparent. West of 

the Rio Grande, Quaternary and Tertiary volcanics are the 

predominant rock type. Soluble minerals generally are absent 

in these volcanic rocks. Specific conductance west of the 

river, with the exception of the Mesilla Basin, generally is in 

the range of 0 to 750 microsiemens. Basins east of the Rio 

Grande generally have water with a specific conductance of 

751 to 2,250 microsiemens (fig. 21). Paleozoic rocks make 

up most of the basin boundaries (fig. 3). In contrast, the
A38 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

MONTEZUMA -»

g

i COLO ,

NEW MEXICO" ~

EXPLANATION

Ground water specific conductance, 

in microsiemens per centimeter 

at 25 degrees Celsius

0 to 750 

751 to 2,250 

2,251 to 5,000 

Greater than 5,000

APPROXIMATE BASIN 

FILL-BEDROCK CONTACT

FIGURE 21. Specific conductance of ground water in the basin-fill aquifer system.
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A39

southern part of the Salt and Eagle Basins and the eastern 

side of the Redlight Draw Basin in west Texas (fig. 1) have 

relatively large areas where water has a specific conductance 

less than 750 microsiemens; these areas correspond closely 

to the occurrence of volcanic rock along basin boundaries.

The ground water in the Mesilla Basin has a specific conductance in the range of 751 to 2,250 microsiemens that may 

result from geology, inflow, irrigation-return flow, or geothermal activity. Paleozoic rocks in the Robledo, Organ, and 

Franklin Mountains (fig. 14) comprise the recharge areas for 

the basin and may be a source of soluble minerals. Inflow of 

water from the Jornada del Muerto Basin (fig. 1) with a specific conductance of 751 to 2,250 microsiemens could be a 

source of the Mesilla Basin water. The Jornada del Muerto 

Basin is surrounded by Paleozoic rocks. Recharge from 

applied irrigation water concentrates solutes because of 

evapotranspiration and also increases specific conductance in 

the Rio Grande flood plain. Geothermal areas along the eastern side of the basin contribute water having increased specific conductance (Anderholm, 1992).

In the closed basins in southwestern New Mexico, the specific conductance of ground water generally is less than 750 

microsiemens. Volcanic rocks in recharge areas of the basins 

contribute only small quantities of solutes. Areas of 

increased specific conductance in ground water correspond to 

the location of playas. Water recharged through playa sediments may have increased specific conductance because of 

evaporation during the time water is ponded in the playa.

WATER CHEMISTRY

Six water types are found in the study area, based on the 

occurrence of two major cations and three anions. If the sum 

of the calcium and magnesium equivalents per million was 

greater than 50 percent of the cations, the water was classified 

as calcium plus magnesium cation type. If sodium was 

greater than 50 percent of the cations, the water was classified 

as sodium cation type. Anion percentages were calculated on 

the basis of equivalents per million to determine the predominant anion in the water sample. The water was then classified 

as chloride, sulfate, or bicarbonate anion type.

Because of the division of chemical water types, the majorion evolution method presented in Freeze and Cherry (1979) 

was a useful method to assist in the definition of basin flow 

systems. Freeze and Cherry (1979, p. 242) reported that 

younger water has a predominant bicarbonate anion and is 

low in dissolved solids. This is indicative of an upper zone of 

water in the aquifer system and active ground-water flushing 

through well-leached rocks. Sulfate is the predominant anion 

in the intermediate depth-to-water zone and is indicative of 

water that is usually older than the bicarbonate water. Water

with a predominantly sulfate anion is usually greater in dissolved solids. Chloride anion predominance may be indicative of the oldest of ground waters, a lower zone of sluggish 

ground-water flow with large dissolved-solids concentration. 

Flow-system characteristics associated with anions were used 

to assist in the interpretation of water-quality data and to 

make inferences about regional and basin flow systems. Cation concentrations were used to indicate processes that might 

be active in the flow systems.

Figure 22 is a chemical water type map showing the dominant ions in ground water from the basin-fill aquifer system. 

Generally, calcium and magnesium are the predominant cations and bicarbonate the predominant anion in ground water 

along the Rio Grande and in the closed basins in southwestern New Mexico. East of the Rio Grande and south of the 

Socorro Basin, extending to the northern Mesilla and Tularosa-Hueco Basins and the northern Salt Basin in west 

Texas, calcium plus magnesium sulfate generally is the 

chemical water type. In the southern Tularosa-Hueco Basin, 

the water contains sodium chloride. Sodium sulfate water 

occurs on the west side of the Albuquerque-Belen Basin and 

along the flood plain of the Rio Grande in the southern part 

of the Albuquerque-Belen Basin into the La Jencia Basin. 

The basins in west Texas, with the exception of the northern 

part of the Salt Basin, have water types of calcium plus magnesium bicarbonate and sodium bicarbonate similar to closed 

basins in western New Mexico.

All six chemical water types occur in the study area. Each 

water type will be discussed in relation to processes that 

might be operating in the geochemical system. Only three 

small areas of calcium and magnesium chloride water occur 

in the study area: one in the Albuquerque-Belen Basin just 

south of the Jemez River, one just west of the Rio Grande in 

the Palomas Basin, and one in the west-central TularosaHueco Basin. The geology of these three areas is similar to 

the surrounding area. The ground-water temperature and specific conductance are larger south of the Jemez River in the 

Albuquerque-Belen Basin (figs. 20 and 21), indicating the 

possibility of mixing geothermal water from the Jemez geothermal reservoir with water in the basin-fill aquifer system. 

Anderholm (1988, p. 89) reported large chloride concentrations in the Jemez geothermal reservoir, north of the Jemez 

River. Water moving from the geothermal reservoir and mixing with local recharge water may result in the calcium plus 

magnesium chloride water in the Albuquerque-Belen Basin. 

The calcium plus magnesium chloride water in the Palomas 

Basin is near known Geothermal Resource areas, which 

might be the source of this water type. The processes that 

produce this type of water in the Tularosa-Hueco Basin are 

not known due to lack of data in this area.
A40 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

0 20 40 MILES

I I I

0 20 40 KILOMETERS

34'

33°

EXPLANATION

Water-chemistry types

 Calcium plus magnesium chloride 

m| Calcium plus magnesium sulfate

Calcium plus magnesium bicarbonate

Sodium chloride

Sodium sulfate

Sodium bicarbonate

APPROXIMATE BASIN 

FILL-BEDROCK CONTACT

32°

FIGURE 22. Chemical water types in the basin-fill aquifer system.
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A41

Calcium plus magnesium sulfate water is most common in 

the south-central and southeast parts of the study area but 

also is found in most basins south of the San Luis Basin. 

This type of water can be associated with Mesozoic and 

Paleozoic rocks (fig. 3). The Mesozoic and Paleozoic rocks 

commonly are a source of sulfate.

Calcium plus magnesium bicarbonate water is the most 

common water type in the study area. This type of water is 

characteristic of recharge water and has low values of specific conductance (fig. 21).

Sodium chloride water is found in several basins south of 

the Espanola Basin. The presence of sodium chloride water 

probably is the result of different processes in each of the 

different basins. In the Albuquerque-Belen Basin, inflowing 

ground water from the San Juan Basin to the west is the 

source of the sodium chloride (Anderholm, 1988, p. 67). 

Inflowing ground water along fault zones west of the Albuquerque-Belen Basin is a sodium chloride brine; the specific 

conductance of water flowing into the basin is greater than 

20,000 microsiemens. Small areas of sodium chloride water 

occur in the Engle and Palomas Basins and in the northern 

part of the Mesilla Basin. These areas are in or near Known 

Geothermal Resource Areas. Upwelling of water from a 

deep geothermal reservoir may be the source of this sodium 

chloride water.

Sodium chloride water also is found in the southern end of 

the Mesilla Basin, the southern end of the Tularosa-Hueco 

Basin, and the northern part of the Eagle Basin in west 

Texas. These areas are not associated with a known geothermal source or with inflow of water from adjacent basins with 

large sodium or chloride concentrations. Dane and Bachman 

(1965) and the Bureau of Economic Geology (1968) have 

mapped the Permian Hueco Limestone and Yeso Formation 

as the primary rock types in these areas. Dissolution of halite 

from the formations may be the process responsible for 

sodium chloride water in these basins.

Sodium sulfate and sodium bicarbonate water is found in 

discharge areas in most basins (fig. 22). In closed basins, 

sodium sulfate and sodium bicarbonate ground water is 

present in areas of playas. A clay-rich aquifer matrix can 

supply cation-exchange sites for exchanging calcium or magnesium for sodium.

RECHARGE

Recharge to the ground-water system was estimated for all 

basins in the study area using the "mountain water-budget" 

and the "mountain-yield" methods of Hearne and Dewey 

(1988). Total recharge and recharge from specific basin 

boundaries are listed in table 8. Recharge estimates from the 

western boundary of the San Luis Basin north of the San 

Luis Hills were determined using the mountain water-budget

method. In the remainder of the study area, the volume of 

water that discharges to the alluvial aquifers was estimated 

using the mountain water-yield method. Precipitation on the 

basin surface was not included in the total recharge value 

because it is assumed to be lost by evapotranspiration while 

in the first few inches of the soil. Unit recharge is the annual 

estimated recharge, in cubic feet per second, divided by total 

alluvial area for a basin, in square miles. Unit recharge and 

recharge per length of basin boundary for each basin are 

given in table 9. Recharge from the eastern and western 

boundaries of each basin was computed by dividing recharge 

from the mountain front by mountain-front length. Recharge 

amount and general locations are shown in figure 23.

Recharge is greater in the northern basins than in the 

southern basins. Runoff from high mountains adjacent to the 

basins is the primary source of recharge. The San Luis Basin 

has the largest quantity of estimated unit recharge. Average 

annual estimated mountain water-budget and mountain-front 

recharge is about 3,580 ftVs, nearly 15 times the recharge to 

the Espanola Basin, the basin in the study area with the next 

largest recharge rate (table 8). The ratio of estimated 

recharge from the western boundary divided by the western 

mountain-front length of the San Luis Basin is more than 12 

times the ratio for recharge from the western boundary of the 

Espanola Basin, to the south.

The Espanola Basin has the second largest unit recharge, 

followed by the Engle Basin (table 9). The large recharge is 

due to the adjacent high mountains that receive large 

amounts of precipitation. Recharge on the west side of the 

Engle Basin from the San Mateo Mountains and the small 

alluvial area of the basin contribute to the large unit recharge 

although there is no significant recharge from the east side of 

the basin. The Mesilla Basin has the smallest unit recharge 

along the Rio Grande. The absence of large, high mountain 

areas together with small amounts of precipitation accounts 

for the small unit recharge.

Estimated recharge to basins located partly in Mexico is 

greatest for the Tularosa-Hueco Basin. Runoff from the Sacramento Mountains to the east of the basin produces most of the 

recharge. Recharge from west of the basin also is greater than 

for the Eagle, Redlight Draw, and Presidio Basins (table 9).

Among closed basins (fig. 2), the San Agustin Basin has 

the largest unit recharge. This basin is surrounded by relatively large, high mountain areas. In contrast to most other 

basins in the study area, the San Agustin Basin also has a 

significant quantity of recharge from the northern and southern boundaries of the basin. The only other basins to receive 

recharge from the north or south are the Jornada del Muerto 

and Mimbres Basins.
TABLE 8. Estimated recharge to alluvial basins.

[ft3/s, cubic feet per second; mi2, square miles; mi, miles; , no data]

Basin

San Luis

Espanola

Albuquerque-Belen

and Santo Domingo

Socorro

La Jencia

San Agustin

San Marcial

Engle

Palomas

Jornada del Muerto

Mesilla

Tularosa-Hueco

Mimbres

Hachita

Playas

Animas

Lordsburg

Salt

Eagle

Redlight Draw

Presidio

Total 

estimated 

recharge1 

(ft3/s)

3,580

246

114

8

5

49

11

26

33

24

6

136

17

3

9

2

3

68

2

21

4

Alluvial 

area 

(mi2)

3,640

1,410

3,150

346

208

1,260

535

455

766

2,340

1,420

5,120

3,060

491

531

201

361

2,180

618

802

448

Estimated 

recharge 

from 

eastern 

boundary 

(ft3/s)

780

129

104

2

0

4

0

0

5

8

4

98

6

0

3

2

3

27

2

9

4

Eastern 

boundary 

length 

(mi)

201

139

147

28

25

30

13

21

38

122

41

400

105

28

71

40

73

232

35

75

74

Estimated 

recharge 

from 

western 

boundary 

(ft3/*)

2,800

117

10

6

5

5

11

26

28

1

2

38

2

3

6

0

0

41

0

12

Western 

boundary 

length 

(mi)

292

156

195

36

31

15

81

63

105

125

84

236

111

55

59

27

73

245

34

98

~

R

16 ft3/s, 139 

163 mi so

15ft3/s, 111 

No data from 

7 ft3/s, 108 

interior re

No data from 

No data from 

No data from 

not include precipitation on the basin surface that is assumed to be lost to evapotranspiration.
TABLE 9. Unit recharge (ratios of total estimated recharge to alluvial area) and estimated recharge from basin boundaries per boundary length.

[ft3/s, cubic feet per second; mi2 , square miles; mi, miles; , no data]

Total Eastern boundary Western boundary Northern boundary 

recharge 1 (ft3/s) recharge (ft3/s) recharge (ft3/s) recharge (ft3/s) 

____Basin_______ Alluvial area (mi2) _____Length (mi)_______Length (mi)________Length (mi)____

SanLuis........................................ 0.983 188 9^59 "

Espanola....................................... .175 0.928 0.750

Albuquerque-Belen c

and Santo Domingo.................... .036 .707 .051 - %§>

Socorro......................................... .023 .071 .167 -- |

LaJencia....................................... .024 .000 .161 -- >

San Agustin.................................. .039 .133 .333 0.116 £San Marcial.................................. .021 .000 .136 ~ 1

Engle............................................ .057 .000 .413 - £

Palomas........................................ .043 .132 .267 - 1JornadadelMuerto....................... .010 .066 .008 .135 RMesilla.......................................... .004 .098 .024 - >Tularosa-Hueco............................ .030 .245 .161 -- §

Mimbres....................................... .006 .057 .018 .065 S

§ 

Hachita......................................... .006 .000 .055 -- 3

Playas........................................... .017 .042 .102 -- |

Animas......................................... .010 .050 .000 - I

Lordsburg..................................... .008 .041 .000

Salt................................................ .009 .054

Eagle............................................. .003 .057 .000

Redlight Draw.............................. .026 .120 .122

Presidio......................................... .031____________.116___________.167___________-_______

not include precipitation on the basin surface that is assumed to be lost to evapotranspiration.
A44 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

Annual average estimated recharge 

in the San Juan Mountains, in 

~ cubic feet per second

SANM1GUEL

J i^|^t|Annual average estimated rechargeV$\ |(. 

f (sS^ from interior mountains, in cubic \vj j. 

I feet Per second X. J

EXPLANATION

Area of basin fill Indicates extent 

of basin fill within basin boundaries, 

some of which may not be saturated.

Basin boundary Number and name 

listed below

1. San Luis

2. Espanola

3. Santo Domingo

4. Albuquerque-Belen

5. Socorro

6. La Jencia

7. San Agustin

8. San Marcial

9. Engle

10. Palomas

11. Jornada Del Muerto

12. Mesilla

13. Tularosa-Hueco

14. Mimbres

15. Hachita

16. Playas

17. Animas

18. Lordsburg

19. Salt

20. Eagle

21. Redlight Draw

22. Presidio

Annual average estimated recharge 

from the eastern basin boundary, in 

cubic feet per second

Annual average estimated recharge 

from the western basin boundary, in 

cubic feet per second

Annual average estimated recharge 

from the northern basin boundary, 

in cubic feet per second

Annual average estimated recharge 

from the southern basin boundary, 

in cubic feet per second

FIGURE 23. Estimated recharge to the basin-fill aquifer system.
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A45

WATER USE

A comprehensive water-use study for the study area was 

not done due to the large number of basins, the complexities 

of determining the amount of water used from ground-water 

and surface-water sources for irrigation, and the lack of significant stress in many basins. The percentage of water from 

each source varies, depending on irrigation practices, the 

amount of surface water available, and the crop type. In 

basins other than the Albuquerque-Belen and Mesilla, municipal, domestic, and industrial uses are not a primary use of 

water; therefore, irrigated acreage was compiled as an indicator of water use. Water use in the study area was most accurately estimated in the San Luis (Hearne and Dewey, 1988), 

Albuquerque-Belen (Kernodle and others, 1987), Mesilla 

(Frenzel and Kaehler, 1992), and Animas Basins (O'Brien 

and Stone, 1983) during development of ground-water flow 

models. Detailed water-use information for the above mentioned basins may be found in the discussion of the particular basin and in the referenced reports.

Table 10 summarizes irrigated acreage by basin and source 

of water. The water used per acre is variable, depending on 

the quantity of precipitation, the source of the water (ground 

or surface), the efficiency of the farm operation, and the crop 

being irrigated.

Eighty-one percent of the irrigated acreage is in basins 

adjacent to the Rio Grande (fig. 24). With the exception of 

the San Luis Basin, where the percentage of the acreage irrigated by surface or ground water is not available, about 60 

percent of the irrigated acreage is irrigated with both surface 

and ground water. In the open drainage basins, 24 percent of 

the irrigated acreage is irrigated by only surface water, 10 

percent is irrigated by only ground water, and 66 percent is 

irrigated by both.

In closed basins ground water is the source of water for 93 

percent of the irrigated acreage. Surface water is the source 

for 6 percent of the irrigated acreage from the Mimbres 

River in the Mimbres Basin. Mixed surface water and ground 

water are the source for 1 percent of the irrigated acreage.

In basins where the population is growing, ground-water 

withdrawals for uses other than agriculture are becoming 

greater. Percentages for other than agricultural use given 

below are calculated using data from Sorensen (1977 and 

1982), Wilson (1986), and Don White (Hydrologist, U.S. 

Geological Survey, oral commun., 1987). In 1975, 1980, and 

1985, ground-water withdrawals for uses other than agriculture in the Albuquerque-Belen Basin were 94, 90, and 95 

percent, respectively, of the total ground-water withdrawal. 

Total withdrawals were 135,000, 161,000, and 152,000 acrefeet in each respective year. In the Mesilla Basin, which has 

a smaller population and less industrial development, nonagricultural ground-water withdrawals were 32, 41, and 45

percent of the total ground-water withdrawals in 1975, 1980, 

and 1985, respectively. Total withdrawals from the system 

were 108,000, 99,000, and 108,000 acre-feet in each respective year. Water use is predominantly for agriculture in the 

Socorro Basin. Only the town of Socorro has significant 

municipal withdrawals. Therefore, nonagricultural uses were 

21, 13, and 29 percent of total ground-water withdrawals for 

1975, 1980, and 1985, respectively. Total withdrawals were 

40,000, 32,800, and 19,700 acre-feet in each respective year. 

No significant nonagricultural ground-water withdrawals 

were made in the Mimbres Basin. Therefore, only 3, 4, and 

4 percent of the total ground-water withdrawals of 156,000, 

122,000, and 112,000 acre-feet, respectively, were used for 

nonagricultural uses in 1975, 1980, and 1985.

REGIONAL SYNTHESIS

Structurally and hydrologically the 22 basins of the Southwest Alluvial Basins study area can be divided into two general types: open basins that have surface-water discharge 

and closed basins that have no surface-water discharge. The 

Rio Grande is the primary hydrologic connection among 

basins that have surface-water discharge.

Basin-fill deposits, including fan deposits, river alluvium, 

and unconsolidated to consolidated sediments and some volcanics associated with the Santa Fe Group or Gila Conglomerate, are hydraulically connected and form an aquifer 

system. Lithologies reflect the geologic setting and depositional history of the basins; predominantly coarse-grained 

sediments were deposited by the relatively high energy, 

ancestral Rio Grande; whereas, fine-grained lake or playa 

sediments were deposited in topographically closed basins.

Ground-water flow simulations show that aquifer storage 

supplies from 25 percent of ground water withdrawn in the 

Albuquerque-Belen Basin to 10 percent withdrawn in the 

Mesilla Basin. The remainder of the ground water withdrawn 

comes from surface water and capture of water that otherwise would have been lost to evapotranspiration.

A regional potentiometric-surface map of the basin-fill aquifer system indicates that ground-water movement is generally 

from west and east to the center of the valleys and then southward. Throughout most of the study area, the Rio Grande flood 

plain acts as a drain for the basin-fill aquifer system.

Generally, calcium and magnesium are the predominant 

cations and bicarbonate is the predominant anion in ground 

water in basins along the Rio Grande and in the closed 

basins in southwestern New Mexico and western Texas. 

South and east of the Socorro Basin, extending into western 

Texas, calcium plus magnesium sulfate generally is the 

chemical water type. In the southern Tularosa-Hueco Basin, 

the water contains sodium chloride.
A46 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

TABLE 10. Irrigated acreage in alluvial basins, 1978-80.

[NA, only irrigation total is available; , no data]

Basin

Surface 

water

Ground 

water

Combined 

water Total

San Luis.............................. NA

Espanola.............................. 22,600

Santo Domingo................... 34,100

Albuquerque-Belen............. 5,500

Socorro................................ 2,300

La Jencia.............................

San Agustin.........................

San Marcial.........................

Engle................................... 590

Palomas............................... 70

Jornada del Muerto.............

Mesilla.................................

Tularosa-Hueco................... 650

Mimbres.............................. 11,000

Hachita................................

Playas..................................

Animas................................

Lordsburg............................

Salt......................................

Eagle...................................

RedlightDraw.....................

Presidio...............................

NA

420

1,200

600

320

14,200

440

5,700

6,400

51,000

12,000

9,100

14,000

73,000

NA 

730

24,600 

130

12,000

330

22,700

69,300

47,800

1,000

1,100

5,000

796,500

23,750

59,900

5,630

14,300

600

1,240

36,970

440

75,000

54,850

63,000

12,000

1,100

5,000

9,100

14,000

73,000

Totals ^6,810 1 188,380 1 184,690 1,246,380

totals do not include acreage in the San Luis Valley, Colorado.

Principal processes that influence the chemistry of ground 

water in the study area are varied. The mixing of water from 

adjacent ground-water systems, geothermal systems, and 

along faults modifies water chemistry in the basin-fill aquifer 

system. The presence of Mesozoic and Paleozoic rocks along 

ground-water flow paths causes increases in ions dissolved 

from the rock. Ion exchange in clay-rich aquifer matrix 

allows cation exchange of calcium or magnesium for sodium.

Recharge is greater in the northern basins than in the 

southern basins. Runoff from high mountains adjacent to the 

basins is the primary source of recharge. Average annual estimated recharge ranges from 3,580 ft3/s in the San Luis Basin 

to 6 ft3/s in the Mesilla Basin.

Water use in the study area is changing with time and varies from basin to basin. The percentage of ground water 

withdrawn for nonagricultural uses is increasing as urban
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A47

£7-

UNITEp-Jr ESTATES

K iiillhnLiiCM

EXPLANATION

Irrigated area 

Boundary of basin fill

FIGURE 24. Irrigated acreage, 1978-80.
A48 SOUTHWEST ALLUVIAL BASINS RASA PROJECT

areas and population in these areas increase. From 1975 to 

1985 there was a 1-percent increase in nonagricultural 

ground-water withdrawals in the Albuquerque-Belen Basin, 

which represents an increase of more than 17,000 acre-feet. 

Similarly, there was a 1-percent increase in nonagricultural 

ground-water use in the Mimbres Basin relative to the total 

ground-water withdrawal. This actually amounts to a 200- 

acre-foot decrease in the amount of ground water withdrawn 

for nonagricultural use because of the overall decrease in 

total ground-water withdrawal from 1975 to 1985.

SELECTED REFERENCES

Anderholm, S.K., 1987, Hydrogeology of the Socorro and La Jencia Basins, 

Socorro County, New Mexico: U.S. Geological Survey WaterResources Investigations Report 84-4342, 62 p.

 1988, Ground-water geochemistry of the Albuquerque-Belen Basin, 

central New Mexico: U.S. Geological Survey Water-Resources Investigations Report 86-4094, 110 p. 

-1992, Water quality and geochemistry of the Mesilla Basin, in Frenzel, P.P., and Kaehler, C.A., Geohydrology and simulation of groundwater flow in the Mesilla Basin, Dona Ana County, New Mexico, and 

El Paso County, Texas: U.S. Geological Survey Professional Paper 

1407-C, 105 p.

Baltz, E.H., 1978, Resume" of 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.

Birch, F.S., 1980a, Geophysical evaluation of basin hydrologic characteristics in the central Rio Grande-Part I, Gravity models of the Albuquerque-Belen Basin: Unpublished report prepared for the U.S. 

Geological Survey by the University of New Mexico under contract 

no. 14-08-0001-17879, 30 p. [Available from the U.S. Geological Survey, Water-Resources Division, New Mexico District Office, Albuquerque, New Mexico.]

 1980b, Three-dimensional gravity model of the basin hydrologic 

parameters in New Mexico: Unpublished report prepared for the U.S. 

Geological Survey by the University of New Mexico under contract no. 

14-08-0001-17899, 27 p.

Bloodgood, D.W., 1930, The ground water of the middle Rio Grande valley 

and its relation to drainage: Las Cruces, New Mexico Agriculture 

Experimental Station Bulletin 184, 60 p.

Bryan, Kirk, 1938, Geology and ground-water conditions of the Rio Grande 

depression in Colorado and New Mexico, in National Resources Committee, Regional Planning, Part VI~The Rio Grande Joint Investigation 

in the Upper Rio Grande Basin in Colorado, New Mexico, and Texas, 

1936-37: U.S. Government Printing Office, v. 1, pt. 2, p. 197-225.

Bureau of Economic Geology, 1968, Geologic Atlas of Texas, Van Horn-El 

Paso: University of Texas at Austin, scale 1:250,000.

Chapin, C.E., 1971, The Rio Grande Rift, Part 1-Modifications and additions, in Guidebook of the San Luis Basin, Colorado: New Mexico 

Geological Society, 22d Field Conference, p. 191-201.

Chapin, C.E., and Seager, W.R, 1975, Evolution of the Rio Grande Rift in 

the Socorro and Las Cruces areas: New Mexico Geological Society 

Guidebook, 26th Field Conference, p. 297-321.

Conover, C.S., 1954, Ground-water conditions in the Rincon and Mesilla 

Valleys and adjacent areas in New Mexico: U.S. Geological Survey 

Water-Supply Paper 1230, 200 p.

Crouch, T.M., 1985, Potentiometric surface, 1980, and water-level changes, 

1969-80, in the unconfined valley-fill aquifers of the San Luis Basin,

Colorado and New Mexico: U.S. Geological Survey Hydrologic-Investigations Atlas HA-683, 2 sheets, scale 1:250,000.

Dane, C.H., and Bachman, G.O., 1965, Geologic map of New Mexico: U.S. 

Geological Survey Geologic Map, 2 sheets, scale 1:500,000.

Emery, P.A., Patten, E.P., and Moore, J.E., 1975, Analog model study of the 

hydrology of the San Luis Valley, south-central Colorado: Colorado 

Water Resources Circular 29, 21 p.

Emery, P.A., Snipes, R.J., Dumeyer, J.M., and Klein, J.M., 1973, Water in 

the San Luis Valley, south-central Colorado: Denver, Colorado Water 

Conservation Board Water-Resources Circular 18, 26 p.

Freeze, R.A., and Cherry, J.A., 1979, Groundwater: Engtewood, N.J., Prentice-Hall, 604 p.

Frenzel, P.F., and Kaehler, C.A., 1992, Geohydrology and simulation of 

ground-water flow in the Mesilla Basin, Dona Ana County, New Mexico, and El Paso County, Texas, with a section on Water quality and 

geochemistry by S.K. Anderholm: U.S. Geological Survey Professional 

Paper 1407-C, 105 p.

Gross, G.W., and Wilcox, Ralph, 1981, Ground water circulation in the 

Socorro Geothermal Area, Part 3, in Icerman, Larry, Starkey, Arlene, 

and Trentman, Nora, eds., State-coupled low-temperature geothermal 

resource assessment program, fiscal year 1980: Final Technical Report 

DOE/ID, 01717-2, p. 2/95-2/191.

Hawley, J.W., 1978, Guidebook to Rio Grande Rift in New Mexico and 

Colorado: Socorro, New Mexico Bureau of Mines and Mineral 

Resources Circular 163, 241 p.

Hearne, G.A., and Dewey, J.D., 1988, Hydrologic analysis of the Rio 

Grande Basin north of Embudo, New Mexico, Colorado and New 

Mexico: U.S. Geological Survey Water-Resources Investigations 

Report 86-4113, 244 p.

Jiracek, G.R., 1982, Geophysical evaluation of basin hydrological characteristics in the central Rio Grande Rift-Part III, Electrical resistivity 

investigations: Unpublished report prepared for the U.S. Geological 

Survey by the University of New Mexico under contract no. 14-08- 

0001-17879, 109 p. [Available from the U.S. Geological Survey, 

Water Resources Division, New Mexico District Office, Albuquerque, 

New Mexico.]

Kaehler, C.A., 1990, Lithology of basin-fill deposits in the AlbuquerqueBelen Basin: U.S. Geological Survey Water-Resources Investigations 

Report 89-4162, 14 p.

Kelley, V.C., 1977, Geology of the Albuquerque Basin, New Mexico: 

Socorro, New Mexico Bureau of Mines and Mineral Resources Memoir 33, 60 p.

Kernodle, J.M., 1992, Summary of U.S. Geological Survey ground-water 

flow models of basin-fill aquifers in the Southwest Alluvial Basins 

Region, Colorado, New Mexico, and Texas: U.S. Geological Survey 

Open-File Report 90-361, 81 p.

Kernodle, J.M., Miller, R.S., and Scott, W.B., 1987, Three-dimensional 

model simulation of transient ground-water flow in the AlbuquerqueBelen Basin, New Mexico: U.S. Geological Survey Water-Resources 

Investigations Report 86-4194, 86 p.

Kernodle, J.M., and Scott, W.B., 1986, Three-dimensional simulation of 

steady-state" ground-water flow in the Albuquerque-Belen Basin, New 

Mexico: U.S. Geological Survey Water-Resources Investigations 

Report 84-4353, 58 p.

King, W.E., Hawley, J.W, Taylor, A.M., and Wilson, R.P., 1971, Geology 

and ground-water resources of central and western Dona Ana County, 

New Mexico: Socorro, New Mexico Institute of Mining and Technology, State Bureau of Mines and Mineral Resources Hydrologic Report 

1, 64 p.

Leggat, E.R., Lowry, M.E., and Hood, J.W, 1962, Ground-water resources 

of the lower Mesilla Valley, Texas and New Mexico: Texas Water Commission Bulletin 6203, 191 p.

National Oceanic and Atmospheric Administration, 1980, Climates of the 

States: Detroit, Mich., Gale Research Company, v. 2., p. 589-1175.
SOUTHWEST ALLUVIAL BASINS, NEW MEXICO AND ADJACENT STATES A49

O'Brien, K.M., and Stone, W.J., 1983, A two-dimensional hydrologic model 

of the Animas Valley, Hidalgo County, New Mexico: Socorro, New 

Mexico, Bureau of Mines and Mineral Resources Open-File Report 

133, 60 p.

Ramberg, J.B., Cook, F.A., and Smithson, S.B., 1978, Structure of the Rio 

Grande Rift in southern New Mexico and west Texas based on gravity interpretation: Geological Society of America Bulletin, v. 89, no. 

1, p. 107.

Riecher, R.E., ed., 1979, Rio Grande Rift: Tectonics and Magmatism, Washington, D.C., American Geophysical Union, 438 p.

Seager, W.R., and Morgan, Paul, 1979, Rio Grande Rift in southern New 

Mexico, west Texas, and northern Chihuahua, in Riecher, R.E., ed., Rio 

Grande rift, tectonics, and magmatism: Washington, D.C., American 

Geophysical Union, p. 87-106.

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.

 1982, Water use by categories in New Mexico counties and river 

basins, and irrigated and dry cropland acreage in 1980: New Mexico 

State Engineer Technical Report 44, 51 p.

Stone, W.J., and Mizell, N.H., 1979, Availability of geological and geophysical data for the eastern half of the U.S. Geological Survey's Southwestern Alluvial Basins regional aquifer study: Socorro, New Mexico 

Bureau of Mines and Mineral Resources Open-File Report 109, 80 p.

Taylor, A.M., 1967, Geohydrologic investigations in the Mesilla Valley, New 

Mexico: Las Cruces, New Mexico State University, unpublished M.S. 

thesis, 130 p.

Tweto, Ogden, 1978, Tectonic map of the Rio Grande Rift system in Colorado, in Hawley, J.W., compiler, Guidebook to Rio Grande Rift in New 

Mexico and Colorado: Socorro, New Mexico Bureau of Mines and 

Mineral Resources Circular 163, 241 p.

Uitti, P.B., 1980, Interpretation of seismic reflection data from southern San 

Luis Valley, south-central Colorado: Golden, Colorado School of 

Mines, unpublished M.S. thesis, 49 p.

U.S. Environmental Protection Agency, 1986, Secondary maximum contaminant levels (section 143.3 of part 143, national secondary drinkingwater regulations): U.S. Code of Federal Regulations, Title 40, Parts 

100 to 149, revised as of July 1, 1986, p. 587-590.

U.S. Salinity Laboratory Staff, 1954, Diagnosis and improvement of saline 

and alkali soils: U.S. Department of Agriculture Handbook 60, 161 p.

West, S.W., and Broadhurst, W.L., 1975, Summary appraisals of the 

Nation's ground-water resources-Rio Grande Region: U.S. Geological 

Survey Professional Paper 813-D, 39 p.

Wilkins, D.W., 1986a, Geohydrology of the Southwest Alluvial Basins 

regional aquifer-systems analysis, in parts of Colorado, New Mexico, 

and Texas: U.S. Geological Survey Water-Resources Investigations 

Report 84-4224, 61 p.

 1986b, Southwest alluvial-basin regional aquifer-systems study in 

parts of Colorado, New Mexico, and Texas, in Sun, R.J., ed., Regional 

aquifer-system analysis program of the U.S. Geological Survey, summary of projects, 1978-84: U.S. Geological Survey Circular 1002, p. 

107-115.

Wilkins, D.W., Scott, W.B., and Kaehler, C.A., 1980, Planning report for the 

Southwest Alluvial Basins (east) regional aquifer-systems analysis, 

parts of Colorado, New Mexico, and Texas: U.S. Geological Survey 

Open-File Report 80-564, 43 p.

Wilson, Brian, 1986, Water use in New Mexico in 1985: New Mexico State 

Engineer Technical Report 46, 84 p.

Wilson, C.A., White, R.R., Orr, B.R., and Roybal, R.G., 1981, Water 

resources of the Rincon and Mesilla Valleys and adjacent areas, New 

Mexico: U.S. Geological Survey Open-File Report 81-487, 305 p.

Woodward, L.A., Callender, J.F, Seager, W.R., Chapin, C.E., Cries, J.C., 

Shaffer, W.L., and Zilinski, R.E., 1975, Tectonic map of Rio Grande 

Region from New Mexico-Colorado border to Presidio, Texas, in 

Guidebook of the Las Cruces Country: New Mexico Geological Society, 26th Field Conference, p. 239.

Wright, A.F., 1978, Bibliography of the geology and hydrology of the Albuquerque greater urban area, Bernalillo and parts of Sandoval, Santa Fe, 

Socorro, Torrance, and Valencia Counties, New Mexico: U.S. Geological Survey Bulletin 1458, 31 p.

 1979a, Bibliography of geology and hydrology, San Juan Basin, New 

Mexico, Colorado, Arizona, and Utah: U.S. Geological Survey Bulletin 1481, 122 p.

 1979b, Bibliography of geology and hydrology, eastern New Mexico: U.S. Geological Survey Water-Resources Investigations 79-76, 

170 p.

Yeo, H.W., 1928, Irrigation in Rio Grande Basin in Texas above Fort Quitman and in New Mexico: New Mexico State Engineer Office, 5 v.

Manuscript approved for publication January 19, 1993 

Graphics by Margo VanAlstine 

Photocomposition by Carol Quesenberry 

Edited by Thomas Kohnen

Selected Series of U.S. Geological Survey Publications

Books and Other Publications

Professional Papers report scientific data and interpretations 

of lasting scientific interest that cover all facets of USGS investigations and research.

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lasting scientific interest but are generally more limited in 

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water, and use of water.

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