Ground-Water Hydrology and Water Quality 

of the Southern High Plains Aquifer, 

Melrose Air Force Range, Cannon Air Force 

Base, Curry and Roosevelt Counties,

New Mexico, 2002-03

By Jeff B. Langman, Fredrick E. Gebhardt, and Sarah E. Falk

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the U.S. Air Force, Cannon Air Force Base 

Scientific Investigations Report 2004-5158
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

U.S. Geological Survey, Reston, Virginia: 2004

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

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

World Wide Web: http://www.usgs.gov/

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.

Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report.

Suggested citation:

Langman, J.B., Gebhardt, F.E., and Falk, S.E., 2004, Ground-water hydrology and water quality of the Southern High

Plains aquifer, Melrose Air Force Range, Cannon Air Force Base, Curry and Roosevelt Counties, New Mexico, 2002-03:

U.S. Geological Survey Scientific Investigations Report 2004-5158, 42 p.
iii

Contents

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

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

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

Description of the Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Previous Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Study Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Well Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Ground-Water Sample Collection and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Chlorofluorocarbon, Stable Isotope, and Dissolved Gas Analysis . . . . . . . . . . . . . . . . . . . . 9

Contaminant Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Quality Assurance and Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Ground-Water Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Ground-Water Age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Ground-Water Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Potentiometric Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Ground-Water Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Ground-Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

General Physical and Chemical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Major Ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Nutrients, Organic Carbon, and Dissolved Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Trace Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Stable Isotopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Pesticides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Explosives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Volatile Organic Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Semivolatile Organic Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Total Organic Halogens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Perchlorate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Source Waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Supplemental Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Evaluation of Quality-Control Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Evaluation of Data Outliers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
iv

Figures

1. Map showing location of Melrose Air Force Range, Impact Area, and

monitoring wells. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2. Map showing surface geology of Melrose Air Force Range . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3. Diagram showing lithology and hydrogeology of Ogallala and Chinle

Formations at well MWQ 2, Melrose Air Force Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4. Map showing altitude of the base of the Ogallala Formation at Melrose

Air Force Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5. Map showing age of ground water at Melrose Air Force Range, December 2002 . . . . . . . 13

6. Graphs showing depth to water from land surface in selected wells at

Melrose Air Force Range, 1962-2003 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

7. Graphs showing depth to water from land surface in selected wells at

Melrose Air Force Range, 2002-03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

8. Map showing median ground-water altitudes at Melrose Air Force Range, 2002-03. . . . . 17

9. Map showing median specific-conductance values and dissolved-solids

concentrations in ground water at Melrose Air Force Range, 2002-03 . . . . . . . . . . . . . . . . . 19

10. Piper diagram of ground-water composition at Melrose Air Force Range, 2002-03 . . . . . . 22

11. Plot showing median sodium and chloride concentrations in ground water

at Melrose Air Force Range, 2002-03. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

12. Graph showing carbon dioxide, nitrogen, and oxygen gas concentrations

in ground water at Melrose Air Force Range, December 2002 . . . . . . . . . . . . . . . . . . . . . . . . 25

13. Plot showing median molybdenum and vanadium concentrations in ground

water at Melrose Air Force Range, 2002-03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

14. Graph showing hydrogen and oxygen stable isotopic ratios in ground water

at Melrose Air Force Range, December 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Tables

1. Melrose Air Force Range study area monitoring-well information. . . . . . . . . . . . . . . . . . . . . . 7

 2. Water-quality constituents and laboratory analysis methods . . . . . . . . . . . . . . . . . . . . . . . . . . 8

 3. Median concentrations and ranges of general physical and chemical

properties for ground-water samples collected at Melrose Air Force

Range, June 2002 to March 2003 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

 4. Medians and ranges of major ion concentrations for ground-water samples

collected at Melrose Air Force Range, June 2002 to March 2003 . . . . . . . . . . . . . . . . . . . . . . 21

 5. Medians and ranges of nutrient and total organic carbon concentrations for

ground-water samples collected at Melrose Air Force Range, June 2002

to March 2003 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

 6. Dissolved gas concentrations for ground-water samples collected at Melrose

Air Force Range, December 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

 7. Medians and ranges of trace element concentrations for ground-water samples

collected at Melrose Air Force Range, June 2002 to March 2003 . . . . . . . . . . . . . . . . . . . . . . 26

 8. Stable isotopic ratios for hydrogen and oxygen for ground-water samples

collected at Melrose Air Force Range, December 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

S-1. Data-quality objectives for water-quality analysis, Melrose Air Force Range . . . . . . . . . . . 38

 S-2. Quality-control results for water-quality sampling at Melrose Air Force Range . . . . . . . . . 40

 S-3. Turbidity values and outlier data points for ground-water samples collected

at Melrose Air Force Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
v

Abbreviations

AOC area of concern

Cannon AFB Cannon Air Force Base

CFC’s chlorofluorocarbons

D deuterium

δ (delta) isotope ratio (heavy/light isotope) compared to the Vienna Standard Mean 

Ocean Water minus one unit (δ = (Rsample/Rstandard) - 1) is presented in 

thousands and is normalized

EOD explosive ordnance detonation

MDL method detection limit

MWL Melrose Air Force Range water-level well

MWQ Melrose Air Force Range water-quality well

μg/L micrograms per liter

mg/L milligrams per liter

μS/cm microsiemens per centimeter at 25 degrees Celsius

18O oxygen-18 isotope

‰ (per mil) thousandths

Range Melrose Air Force Range

RCRA Resource Conservation and Recovery Act

SWMU solid waste management unit

USGS U.S. Geological Survey

VSMOW Vienna Standard Mean Ocean Water
vi

Conversion Factors and Datum

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

°F = (1.8 x °C) + 32

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

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

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

in (in.) 2.54 centimeter (cm)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2)

Volume

gallon (gal) 3.785 liter (L)

gallon (gal) 0.003785 cubic meter (m3

)

Flow rate

gallon per minute (gal/min) 0.06309 liter per second (L/s)
Ground-Water Hydrology and Water Quality of the 

Southern High Plains Aquifer, Melrose Air Force Range, 

Cannon Air Force Base, Curry and Roosevelt Counties, 

New Mexico, 2002-03

By Jeff B. Langman, Fredrick E. Gebhardt, and Sarah E. Falk

Abstract

In cooperation with the U.S. Air Force, the U.S. Geological Survey characterized the ground-water hydrology and 

water quality at Melrose Air Force Range in east-central New 

Mexico. The purpose of the study was to provide baseline data 

to Cannon Air Force Base resource managers to make informed 

decisions concerning actions that may affect the ground-water 

system. Five periods of water-level measurements and four 

periods of water-quality sample collection were completed at 

Melrose Air Force Range during 2002 and 2003. The waterlevel measurements and water-quality samples were collected 

from a 29-well monitoring network that included wells in the 

Impact Area and leased lands of Melrose Air Force Range managed by Cannon Air Force Base personnel. The purpose of this 

report is to provide a broad overview of ground-water flow and 

ground-water quality in the Southern High Plains aquifer in the 

Ogallala Formation at Melrose Air Force Range.

Results of the ground-water characterization of the 

Southern High Plains aquifer indicated a local flow system in 

the unconfined aquifer flowing northeastward from a topographic high, the Mesa (located in the southwestern part of the 

Range), toward a regional flow system in the unconfined 

aquifer that flows southeastward through the Portales Valley. 

Ground water was less than 55 years old across the Range; 

ground water was younger (less than 25 years) near the Mesa 

and ephemeral channels and older (25 years to 55 years) in the 

Portales Valley. Results of water-quality analysis indicated 

three areas of different water types: near the Mesa and ephemeral channels, in the Impact Area of the Range, and in the 

Portales Valley. Within the Southern High Plains aquifer, a 

sodium/chloride-dominated ground water was found in the 

center of the Impact Area of the Range with water-quality 

characteristics similar to ground water from the underlying 

Chinle Formation. This sodium/chloride-dominated ground 

water of the unconfined aquifer in the Impact Area indicates a 

likely connection with the deeper water-producing zone. No 

pesticides, explosives, volatile organic compounds, semivolatile organic compounds, organic halogens, or perchlorate were 

found in water samples from the Southern High Plains aquifer 

at the Range.

Introduction

In 2001, Cannon Air Force Base (Cannon AFB) environmental managers implemented an investigation to protect the 

water resources at the Melrose Air Force Range (Range) to 

ensure the continued operation of the Range and all current 

(2004) activities. In cooperation with the U.S. Geological 

Survey (USGS), a hydrologic study was conducted to characterize ground-water hydrology and ground-water quality of the 

unconfined aquifer at the Range. This aquifer is part of the 

western extension of the Southern High Plains aquifer in the 

Ogallala Formation. 

The Range is located in Curry and Roosevelt Counties, 

New Mexico (fig. 1), about 25 mi west of Cannon AFB, and 

covers 87,925 acres (Cannon AFB owned, public domain, and 

restricted easement). The Range was established in 1952 and 

has been in use from its inception to present (2004) as a bombing and air-to-ground gunnery range. The primary user of the 

Range is the 27th Fighter Wing of Cannon AFB, but the Range 

provides support training for aircraft from bases in Alaska, 

Arizona, Arkansas, Colorado, Idaho, Louisiana, Missouri, 

North Dakota, and Texas as well as other bases in New Mexico. 

Live ordnance was used at the Range from 1952 to 1969, affecting an area of about 7,000 acres (Cannon Air Force Base, 2002).

The Impact Area of the Range (inner area of Range used 

for aircraft target practice), northeast of the landform known as 

“the Mesa,” consists of grasslands with a grid of access roads 

and bombing targets (vehicles, aircraft, and artificial targets) 

and is defined by a historical boundary that previously delineated the extent of the entire Range (fig. 1). In 1990-91, the 

boundary of the Range was expanded through the acquisition of 

agricultural and range land parcels on all sides. These parcels 

(leased lands) are currently part of Range property but are 

leased to the prior owners for continued use as agricultural and 

range land. Leaseholders use the unconfined aquifer for irrigation and stock watering.
2 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Figure 1. Location of Melrose Air Force Range, Impact Area, and monitoring wells.

The Mesa

4,200

MWQ 4 

MWQ 5 

MWQ 3 

MWQ 8 

MWQ 7 MWQ 6 

MWQ 16

MWQ 13

MWQ 12

MWQ 11

MWQ 10

MWQ 17

MWQ 14

MWQ 15

MWQ 1 

MWL 1 

MWL 5 

MWL 4 

MWL 7 

MWL 3 

MWL 2 

MWL 9 

MWL 8 

MWL 6 

MWL 12

MWL 11

MWL 10

MA03

MA02

MA01 MA04

SWMU 118

SWMU 115

SWMU 114

SWMU 117

MWQ 2 

MWQ 9 

4,500

4,500

4,400

4,300

4,600

4,500

4,400

4,300

4,600

4,500

4,600

4,500

4,400

4,300

4,650

4,700

4,500

4,600

4,500

4,400

4,300

4,650

4,700

Las Cruces

Portales

New Mexico

Cannon

Air Force

Base 

Enlarged Area

Albuquerque

Melrose

Air Force

Range 

Roosevelt County

Curry County

60

MILES

KILOMETERS

0

024

Base derived from U.S. Geological National Elevation Dataset 2 4

County line derived from U.S. Bureau of the Census

Topographic contour—Contour interval 50 feet. Vertical coordinate information is referenced to NAVD 88 

Water-quality and water-level well and well number

Water-level well and well number

Well completed in Chinle Formation and well number

Hand-dug well with open wall construction, completed in Ogallala Formation and well number

Area of concern and site number

Solid waste management unit and site number

EXPLANATION

MA01

SWMU 114

MWQ 1

MWL 1

MWQ 2

MWQ 9

4,300

Curry County

Roosevelt County

County Road County Road

Krider Road Krider Road

Main Access Road Main Access Road

County Road

Krider Road

Main Access Road

Impact Area Impact Area

Melrose Air Force Range Melrose Air Force Range

Range Headquarters Range Headquarters

Impact Area

Melrose Air Force Range

Range Headquarters

Portales Valley Portales Valley

The Mesa The Mesa

Pecos River Pecos River 

Basin

Portales Valley

The Mesa

Pecos River 

Basin

103o50’ 103o45’ 103o40’

34o

20’

34o

15’

Draw

Chapman Canada del Tule ~
Introduction 3

The Range includes eight historical land-use sites that are 

under investigation as part of the Cannon AFB Environmental 

Restoration Program. All eight sites are no longer in use and 

include four solid waste management units (SWMU’s) and four 

areas of concern (AOC’s) (fig. 1). The SWMU’s include three 

areas of solid waste burial (SWMU 114, 115, and 117) and an 

explosive ordnance detonation (EOD) pit (SWMU 118) that 

was created for treatment of unusable munitions but was never 

used (Cannon Air Force Base, 2002). The AOC’s include a cantonment (temporary housing quarters) burial site (MA01), a 

helicopter pad that likely included the storage of petroleum 

products (MA02), a domestic waste burial site (MA03), and a 

munitions burial site (MA04). Range Headquarters (fig. 1) consists of various buildings and storage yards for Range operation. 

Purpose and Scope

This report describes the ground-water hydrology and 

water quality in the Southern High Plains aquifer at the Range. 

The purpose is to provide Cannon AFB resource managers with 

reliable ground-water data and a broad overview of the groundwater system for future planning efforts to protect the aquifer 

and ensure continued operation of the Range and all its current 

(2004) activities. 

A 29-well monitoring network covering the Impact Area 

and leased lands of the Range was used from 2002 to 2003 for 

water-level measurements and water-quality sample collection. 

All ground-water samples were analyzed for specific conductance, dissolved oxygen, turbidity, temperature, pH, dissolved 

solids, alkalinity, cyanide, sulfide, major ions, nutrients, 

organic carbon, and trace elements. Additionally, a single 

ground-water sample from each well was analyzed for organochlorine and organophosphorous pesticides, nitroaromatic 

and nitramine explosives, perchlorate, chlorofluorocarbons 

(CFC’s), hydrogen and oxygen stable isotopes, and dissolved 

gases. One sample from each well in the Impact Area was 

analyzed for volatile organic compounds, semivolatile organic 

compounds, and total organic halogens. All constituents are discussed relative to their spatial and temporal distribution at the 

Range and not to regulatory standards. All samples were collected as “whole” water (unfiltered) samples because of the use 

of unfiltered water on the Range for agriculture and stock-tank 

supply.

Description of the Study Area

The Range is located in the Southern High Plains physiographic region (Fenneman and Johnson, 1946) and lies atop a 

large plateau known as the Llano Estacado that slopes gently to 

the east-southeast from eastern New Mexico into west Texas 

(Fahlquist, 2003). Range topography (excluding the Mesa) is 

open and mostly flat and gently slopes to the northeast. The 

Mesa dominates the southwest part of the Range, is a topographic high for the Range, and is part of the Western Caprock 

Escarpment that defines the western boundary of the Southern 

High Plains aquifer (Nativ, 1988). The Mesa has a plateau area 

of about 7,775 acres ranging in altitude from 4,600 to 4,700 ft 

and forms the surface basin boundary between the Pecos River 

Basin to the west and the Portales Valley to the east (fig. 1). No 

surface-water bodies are located within the Range except minor 

ephemeral channels including the Chapman Draw and the 

Cañada del Tule, which originate at the Mesa (fig. 1). The 

Range is located in the Plains-Mesa Grassland vegetation unit 

(Dick-Peddie, 1993), and vegetation consists of grasses and 

shrubs.

The Range is located within a semiarid region (Tuan and 

others, 1969). The Range area receives an average of 16.30 in. 

of precipitation a year; average minimum and maximum temperatures are 42.1 and 72.6 degrees Fahrenheit (Western 

Regional Climate Center, 2001). Most precipitation at the 

Range falls during the summer months (Western Regional 

Climate Center, 2001), and most of the precipitation is likely 

lost to evaporation. Annual pan evaporation at a weather station 

in Clovis (about 30 mi east of the Range) averages 86.64 in.; 

evaporation is largest from May through August (Western 

Regional Climate Center, 2000). 

Water use at the Range is limited to stock tanks, three irrigation wells, and two domestic wells that supply the Range 

Headquarters. Cannon AFB personnel installed submersible 

pumps in wells around the Range to provide water for a system 

of stock tanks located on the leased lands. Pumpage is not monitored, and pumps operate according to pressure in intermediary 

holding tanks determined by stock-tank water levels. Pumpage 

is largest during the summer months when cattle require more 

water and higher evaporation reduces water levels in stock 

tanks (Kerry Hubbell, Cannon Air Force Base, oral commun., 

2002). Water pumped for the stock-tank system is not treated 

and is fed directly into the distribution system. Two of the irrigation wells are in the northern part of the Range and the third 

irrigation well is in the eastern part. Two wells at Range Headquarters supply water for fire suppression and non-potable 

domestic supply. Water usage is not monitored but is likely 

small because of infrequent fire activity and a total Range personnel of about 20 people. The Range is located in an undeclared ground-water basin of the Southern High Plains aquifer 

in New Mexico (New Mexico Office of the State Engineer, 

2004). 

The geologic structure of the Southern High Plains aquifer 

at the Range includes the Chinle1

, Ogallala, and Blackwater 

Draw Formations. The Chinle Formation of Triassic age forms 

the base of the unconfined Southern High Plains aquifer at the 

Range, consists mostly of clay with some intermixed sand and 

silt, and ranges in thickness from 0 to 400 ft for eastern New 

1The Chinle Formation has various accepted names: Chinle Formation, 

Chinle Formation of the Dockum Group, and Chinle Group (U.S. Geological 

Survey, 2002). All three names have been used for geologic description of 

areas in east-central New Mexico with usage dependent on locally identified 

units. Given a lack of identified units in the Range area, although this upper 

unit is possibly the Redonda Formation of the Chinle Group (Hester and Lucas, 

2001), “Chinle Formation” is used in this report. Locally, this formation is 

known as the “red beds.”
4 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Mexico (McGowen and others, 1977). The Ogallala Formation 

of Tertiary age is the uppermost formation for the central and 

southern parts of the Range and lies unconformably atop the 

upper unit of the eastward-dipping Chinle Formation (Dutton 

and others, 2001). The Ogallala Formation consists of eolian 

sand and silt and fluvial and lacustrine sand, silt, clay, and 

gravel (McLemore, 2001), and can range in thickness from 30 

to 600 ft in eastern New Mexico and west Texas (Gustavson, 

1996). 

The Blackwater Draw Formation of Quarternary age overlies the Ogallala Formation in the northern part of the Range, 

consists mostly of eolian sand deposits, and can range in thickness from 0 to 80 ft for eastern New Mexico (McLemore, 

2001). A caliche layer is typically present in the unsaturated 

zone of the Blackwater or Ogallala Formations in New Mexico 

(Hart and McAda, 1985), buts its characteristics at the Range 

are unknown. Gustavson (1996) indicated that the caliche 

forming the Western Caprock Escarpment was pedogenic 

carbonate that accumulated locally during the Tertiary and 

Quarternary Periods and that other buried caliche layers in the 

Ogallala Formation are not well known. Drilling at the Range 

and Cannon AFB has indicated that caliche is discontinuous, of 

variable thickness, and typically found within 30 ft of the 

surface (Fredrick Gebhardt, U.S. Geological Survey, oral 

commun., 2004).

The surface deposits of the Range consist of sand and 

gravel facies and playa deposits of the Blackwater Draw, Ogallala, and Chinle Formations (fig. 2). Eolian deposits of thin sand 

with interbeds of caliche of the Blackwater Draw Formation 

compose the Mesa surface. The northern part of the Range 

occupies the upper reach of the Portales Valley (fig. 1), and is 

composed of reworked material from the Blackwater Draw and 

Ogallala Formations (McLemore, 2001). Eolian deposits of the 

Blackwater Draw Formation are present in the northern part of 

the Range as sand deposits and dunes, and the Chinle Formation 

is exposed in the southwestern portion of the Range near the 

Mesa.

The saturated Ogallala Formation deposits at the Range 

are within the western boundary of the Southern High Plains 

aquifer (Hart and McAda, 1985). In New Mexico, the Southern 

High Plains aquifer is part of a larger aquifer system extending 

from South Dakota to Texas and is commonly referred to as the 

Ogallala aquifer. The part of the Southern High Plains aquifer 

in New Mexico is composed of hydraulically connected geologic units of late Tertiary or Quaternary age and is underlain by 

rocks of Triassic, Jurassic, and Cretaceous age (Hart and 

McAda, 1985). The unconfined Southern High Plains aquifer is 

composed primarily of the Ogallala Formation (McLemore, 

2001). 

 The Chinle Formation has informally been divided into 

upper and lower units (McGowen and others, 1977; Dutton and 

Simpkins, 1986). The upper unit is mud-rich with discontinuous 

sand deposits (Dutton and Simpkins, 1986), and contains a confined aquifer that typically produces only 1-2 gal/min of water 

(Trauger, 1972). The erosional surface of the upper unit of the 

Chinle Formation creates an uneven contact with the Ogallala 

Formation. The Tertiary deposits filled the valleys, uplands, and 

fluvial channels of the eroded Triassic deposits (Gustavson, 

1996). Coarser material was deposited in the paleochannels and 

finer sediments in the interchannel areas (Fahlquist, 2003). 

Sand and clay layers are known to overlie the Chinle Formation 

in eastern New Mexico and west Texas, thereby creating variable permeabilities across the contact with the overlying formation (Nativ and Gutierrez, 1988).

The unconformity and variable deposition of sediments 

between the Ogallala and Chinle Formations created discontinuous zones of horizontal lithology that produced highly variable 

spatial porosity and permeability. The variable spatial porosity 

and permeability produced a discontinuous aquifer in the Ogallala Formation near the Western Caprock Escarpment. Using 

water levels, Hart and McAda (1985) mapped areas of this discontinuous aquifer at the Range and surrounding area and determined that the discontinuity extends from the Western Caprock 

Escarpment to areas east of the Range within Roosevelt County. 

The unconformity at the contact of the Ogallala and Chinle 

Formations also creates variable vertical permeabilities. Nativ 

(1988) found permeable and low permeable sequences of the 

Ogallala-Chinle contact in Roosevelt County southeast of the 

Range, and found differences in water quality in the Southern 

High Plains aquifer along the Western Caprock Escarpment that 

indicated an upward leakage of Chinle Formation water into the 

Southern High Plains aquifer. 

 Diffuse areal recharge to the Southern High Plains aquifer 

has been estimated to range from 0.01 in. per year (Stone and 

McGurk, 1985) to 1.71 in. per year (Mantei and others, 

1966-67) with most estimates less than 1 in. per year (Musharrafieh and Logan, 1999). Ground water in the New Mexico part 

of the Southern High Plains aquifer is generally suitable for 

domestic, municipal, and irrigation uses. The water typically 

contains large concentrations of calcium, magnesium, and 

bicarbonate and potentially objectionable concentrations of 

chloride and fluoride for domestic use (Hart and McAda, 1985). 

Water from older formations, such as the Chinle, is known to be 

of poorer quality (Nativ, 1988). 

Farmers began using the Southern High Plains aquifer in 

the 1940’s for irrigation, and about 94 percent of the water 

pumped from the entire High Plains aquifer was used for irrigation in 1995 (McGuire and others, 2003). Because of substantial 

annual pumpage from the aquifer (approximately 17 million gal 

in 1995), water levels have been declining in the High Plains 

aquifer since development first began. In New Mexico, water 

levels in the Southern High Plains aquifer have declined less 

than the substantial declines recorded in other States (greater 

than 150 ft in parts of west Texas), but in New Mexico, the saturated thickness of the Southern High Plains aquifer is generally less than 100 ft.

Within New Mexico, ground water in the Southern High 

Plains aquifer generally flows eastward (Hart and McAda, 

1985), which is considered the overall direction of regional flow 

in the unconfined aquifer. Using 1978 water-level data, Hart 

and McAda (1985) estimated the depth to water to be about 

100 ft below land surface throughout the Range. In 1987 and 

1992, the USGS measured depth to water ranging from about 
Introduction 5

Figure 2. Surface geology of Melrose Air Force Range. Modified from New Mexico Bureau of Geology and Mineral Resources, 2003.

MILES

KILOMETERS

0

024

Base derived from New Mexico Bureau of Geology and Mineral Resources 2 4

Geologic Map of New Mexico, 1:500,000, 2003

Eolian deposits, including Blackwater Draw Formation—Quaternary 

Lacustrine and playa deposits, including Blackwater Draw Formation—Quaternary

Eolian deposits, including Blackwater Draw Formation—Quaternary

Alluvial and eolian deposits, including Ogallala Formation—Tertiary

Chinle Formation, undivided—Triassic

EXPLANATION

Impact Area Impact Area

Melrose Air Force Range Melrose Air Force Range

Impact Area

Melrose Air Force Range

103o50’ 103o45’ 103o40’

34o

20’

34o

15’

Qe

Qpl

Qoa

To

Trcu

Qe

Qoa

Qoa

Qe

Qe

Qpl

Trcu

To

To

The Mesa The Mesa

Qe

Qoa

Qoa

Qe

Qe

Qpl

Trcu

To

To

The Mesa
6 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

40 to 125 ft across the Range. In 2000, water levels measured in 

the center of the Range by a private contractor ranged from 50 

to 150 ft below land surface (Dennis Timmons, Cannon Air 

Force Base, written commun., 2002). 

Previous Studies

Although no published hydrologic studies have been conducted at the Range, water-level and water-quality data are 

available. Water levels in 13 of the 29 wells used in this study 

have been measured on multiple occasions since 1962 as part of 

a USGS statewide program. Additionally, water levels in wells 

near the SWMU’s and AOC’s have been measured on three 

occasions by either private contractors or the USGS at the 

request of Cannon AFB as part of their Pollution Prevention 

Program (Dennis Timmons, Cannon Air Force Base, oral 

commun., 2002). Wells at the SWMU’s and AOC’s were 

installed in 1995 for Cannon AFB by the U.S. Army Corps of 

Engineers for pollution prevention monitoring. A declining 

water table has resulted in multiple dry monitoring wells since 

installation. 

In 1996 and 2000, a private contractor collected waterquality samples from selected SWMU and AOC monitoring 

wells. In 1996, the private contractor collected ground-water 

samples from all four wells at SWMU 114 (fig. 1) for analysis 

of major ions and trace elements (Foster Wheeler, Environmental Corporation, written commun., 1996). In 2000, the contractor collected samples from all four wells at SWMU 114, all 

four wells at MA01, and one well at MA02 (fig. 1) for analysis 

of cyanide, major ions, nitrate, trace elements, nitrogen-based 

explosives, and volatile organic compounds. In 2001, the USGS 

collected water-quality samples from eight of the nine monitoring wells sampled by the contractor in 2000 (Fredrick 

Gebhardt, U.S. Geological Survey, oral commun., 2002). These 

samples were analyzed for concentrations of the same constituents as in 2000 with the addition of perchlorate. The results of 

all contractor and USGS ground-water analyses were not published but were submitted to Cannon AFB as informal data 

submissions as part of Cannon AFB’s Pollution Prevention 

Program. No explosives or volatile organic compounds larger 

than laboratory method reporting limits were detected.

In 1993, the USGS conducted an investigation of SWMU 

118 as part of Cannon AFB’s Resource Conservation and 

Recovery Act (RCRA) application for permitting the EOD pit 

(Cannon Air Force Base, 1993). Soil and core samples were 

analyzed for trace elements and explosives. No explosives were 

detected in soil or core samples, and only concentrations of 

beryllium in soil were larger than RCRA action levels (Cannon 

Air Force Base, 1993).

Study Methods

The study design implemented methods described by 

Lapham and others (1997), and ground-water sample collection 

followed guidelines established by Wilde and others (1998). 

Well Sites

Potential monitoring network wells were examined in the 

field with Cannon AFB personnel, and 27 wells were selected 

to be included in the network (fig. 1 and table 1). Twelve wells 

(non-working windmills) were selected only for water-level 

measurements (MWL designator), and 15 wells were selected 

for water-quality sampling and water-level measurements 

(MWQ designator). Seven of the 15 wells had submersible 

pumps previously installed as part of the stock-tank system. The 

remaining eight water-quality wells were previously used as 

windmills, irrigation wells, or monitoring wells. Former windmills and irrigation wells no longer contain installed pumps. All 

27 wells had a single screen set in the unconfined aquifer in the 

Ogallala Formation.

In June 2002, two additional monitoring wells (MWQ 1 

and MWQ 2; fig. 1 and table 1) were installed by the USGS in 

an area devoid of wells. Well MWQ 1 was completed in the 

Ogallala Formation, and well MWQ 2 was completed in the 

upper unit of the Chinle Formation. MWQ 1 initially yielded 

small quantities of water during well development but provided 

insufficient water for sampling. MWQ 1 was possibly screened 

in a discontinuous aquifer zone.

Ground-Water Sample Collection and Analysis 

Water levels were measured below a known, fixed altitude 

from March 2002 to March 2003 using either an electric tape or 

steel tape. Water-quality samples were collected from June 

2002 to March 2003 using one of two methods depending on 

well configuration. Samples from the seven wells with submersible pumps were collected from spigots located between 

the well and holding tanks. Samples from the remaining wells 

were collected using a portable environmental-submersible 

pump. 

Water-quality samples were collected and analyzed as 

whole water for selected constituents depending on the sample 

period (table 2). Whole water was collected because wells at the 

Range provide untreated water for stock tanks throughout the 

Range and for irrigation in the northern and eastern parts of the 

Range.

Standard field measurements of specific conductance, dissolved oxygen, turbidity, pH, and temperature were collected at 

each site during each sample period using portable field meters 

and a flow-through chamber to reduce atmospheric influences. 

Stable field measurements were used to determine sufficient 

purge amounts for sampling formation water.

Median concentrations and ranges were used to evaluate 

spatial and temporal variability. Standard field measurements 

and concentrations of dissolved solids, alkalinity, cyanide, sulfide, major ions, nutrients, organic carbon, and trace elements 

reported in the text are median values. Concentrations of 

CFC’s, stable isotopes, dissolved gases, pesticides, explosives, 

volatile organic compounds, semivolatile organic compounds, 

total organic halogens, and perchlorate are individual sample 

concentrations. 
Introduction 7

Table 1. Melrose Air Force Range study area monitoring-well information.

[All wells, except MWQ 2, were completed in the Ogallala Formation. MWQ 2 was completed in the Chinle Formation. USGS, U.S. Geological Survey; Cannon 

AFB, Cannon Air Force Base; NAVD 88, North American Vertical Datum of 1988; ft bls, feet below land surface; MWQ, Melrose Air Force Range water-level 

and water-quality well; MWL, Melrose Air Force Range water-level well; NA, not available; -----, not applicable; Well depth, study depth (original depth)]

Well number 

(fig. 1)

USGS well site 

identification number

Cannon AFB

common name

Land-surface altitude

(ft above NAVD 88)

Well depth

(ft bls)

Casing 

material

Dedicated 

pump

Wells used for water-quality sampling and water-level measurements

MWQ 1 341714103442501 ----- 4,288.80 134 (125) PVC No

MWQ 2 341714103442502 ----- 4,288.80 240 (245) PVC No

MWQ 3 341820103442601 Ashley pump 4,266.30 163 (164) Steel Yes

MWQ 4 342152103444201 Solar pump 4,200.12 NA (NA) PVC Yes

MWQ 5 342031103464701 Telephone pole 4,229.80 101 (103) Steel Yes

MWQ 6 342048103492701 Homestead 4,268.68 NA (NA) Steel Yes

MWQ 7 342046103503501 Grider at gate 4,258.18 99 (101) Steel Yes

MWQ 8 341720103494701 Below golf ball 4,466.57 113 (NA) Steel No

MWQ 9 341533103485801 Hand dug 4,488.30 42 (60) None No

MWQ 10 341954103503101 Luce jog 4,637.69 58 (60) Steel Yes

MWQ 11 341345103494301 Parker house 4,661.96 NA (NA) Steel Yes

MWQ 12 341828103460001 Eroded tank 4,403.45 63 (NA) Steel No

MWQ 13 341440103411101 Hidden mill 4,277.38 177 (165) Steel No

MWQ 14 341640103470501 EOD pit 4,378.68 120 (NA) PVC No

MWQ 15 341743103470801 MA02MW001D 4,354.29 183 (182) PVC No

MWQ 16 341825103470301 SWMU114MW004 4,321.25 181 (181) PVC No

MWQ 17 341845103475801 MA01MW003 4,341.30 161 (160) PVC No

Wells used for water-level measurements

MWL 1 341658103411901 Mini-mute east 4,237.38 120 (126) Steel No

MWL 2 341758103450401 NE100 mill 4,289.45 139 (NA) Steel No

MWL 3 341956103452201 Luce NW 4,222.34 74 (NA) Steel No

MWL 4 342044103451401 Firebreak fence 4,215.80 57 (NA) Steel No

MWL 5 342155103453101 Glass jog pvc 4,192.67 34 (NA) PVC No

MWL 6 341958103485401 Brackish mill 4,301.08 NA (NA) Steel No

MWL 7 342026103475101 Fence line dip 4,253.91 110 (125) Steel No

MWL 8 342050103485101 Davis trap mill 4,257.51 114 (114) Steel No

MWL 9 342200103475501 Northern end 4,238.52 49 (NA) Steel No

MWL 10 341542103502901 Three mills 4,574.99 51 (NA) Steel No

MWL 11 341254103513501 Luce 480 mill 4,576.70 NA (138) Steel No

MWL 12 341249103470601 County road 4,444.62 58 (62) Steel No
8 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Table 2. Water-quality constituents and laboratory analysis methods.

[USEPA, U.S. Environmental Protection Agency; sample periods: June 2002, September 2002, December 2002, and March 2003; oC, degrees Celsius; 

CFC, chlorofluorocarbon; -----, not applicable]

Analysis constituent or group Description Wells USEPA Method1 Sample periods

Dissolved solids Filterable residue All MCAWW 160.12 June, September, 

December, March

Alkalinity Alkalinity as calcium carbonate All MCAWW 310.1 June, September, 

December, March

Cyanide All SW846 9012A3 June, September, 

December, March

Sulfide All SW846 9030B June, September, 

December, March

Major ions Ca, Mg, Na, K, HCO3, SO4, Cl, F, Br All MCAWW 300.0A June, September, 

December, March

Nutrients Nitrate plus nitrite, ammonia, phosphorus All MCAWW 300.0A June, September, 

December, March

Organic carbon All SW846 9060 June, September, 

December, March

Trace elements Ag, Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, 

Mn, Mo, Ni, Pb, Sb, Se, Tl, V, Zn

All SW846 7470A, 

SW846 6010B

June, September, 

December, March

Organochlorine pesticides 21 chlorine-based pesticides All SW846 8081A June

Organophosphorous pesticides 27 phosphorous-based pesticides All SW846 8141A June

Nitroaromatic and nitramine 

explosives

14 nitrogen-based explosive compounds All SW846 8330 June

Volatile organic compounds 66 organic compounds with low boiling 

points (less than 200 °C)

MWQ 14 - 17 SW846 8260B March

Semivolatile organic 

compounds

107 neutral, basic, and acidic organic 

compounds that are soluble in methylene chloride

MWQ 14 - 17 SW846 8270C March

Total organic halogens All halogenated carbon compounds MWQ 14 - 17 SW846 9020B March

Perchlorate All EPA 314.0 June, March (wells 

MWQ 14-17)

Chlorofluorocarbons CFC-11, 12, and 113 All except MWQ 9 ---- December

Hydrogen isotopes 2

H/1H ratio All except MWQ 9 ---- December

Oxygen isotopes 18O/16O ratio All except MWQ 9 ---- December

Dissolved gases N2, CO2, CH4, Ar All except MWQ 9 ---- December

1All water-quality constituents except CFC’s, stable isotopes, and dissolved gases were analyzed by the U.S. Geological Survey (USGS) contract laboratorySevern Trent Laboratories in Arvada, Colorado. CFC’s, stable isotopes, and dissolved gases were analyzed by the USGS CFC/Dissolved Gas/Isotope Laboratories in Reston, Virginia.

2U.S. Environmental Protection Agency, 1983.

3U.S. Environmental Protection Agency, 1986.
Introduction 9

Small concentrations are discussed relative to method 

reporting limits and method detection limits. Method reporting 

limits are the smallest concentrations at which measurements 

become quantitatively meaningful (quantitation limit) (U.S. 

Environmental Protection Agency, 2000). Method reporting 

limits are typically about three times the method detection limit. 

Method detection limits are defined as the statistically calculated minimum concentration that can be measured with 99 percent confidence that the reported value is greater than zero, and 

are determined from replicate analyses of small concentration 

standards in a typical representative matrix (U.S. Environmental Protection Agency, 2000).

Chlorofluorocarbon, Stable Isotope, and 

Dissolved Gas Analysis

CFC, stable isotope, and dissolved-gas concentrations 

were used to evaluate the age of ground water and associated 

information about recharge, source waters, and chemical and 

(or) biological influences. Ground-water CFC concentrations 

(CFC-11, CFC-12, CFC-113) were compared to known CFC 

atmospheric concentrations during the past 60 years to estimate 

when the water entered the ground-water system as recharge 

(Plummer and Busenberg, 2000). The stable isotopic ratios for 

hydrogen and oxygen plus the concentrations of dissolved 

oxygen, carbon dioxide, methane, and argon were used to evaluate any potential biochemical influences on CFC concentrations during storage. Additionally, isotopic differences were 

used to differentiate potential source waters, and dissolved-gas 

concentrations were used to examine chemical and (or) biological influences on water quality.

Because of fractionation processes (such as evaporation, 

isotopic exchange, and microbial activity), water and solutes 

often develop unique isotopic compositions (ratios of heavy to 

light isotopes) that may be indicative of their source or of the 

processes that formed them (Kendall and Caldwell, 1998). 

Delta (δ) refers to the ratio (R) of heavy to light isotopes 

divided by the Vienna Standard Mean Ocean Water (VSMOW) 

minus one unit (δ = (Rsample/Rstandard) - 1). The isotopic ratio is 

presented in thousandths (per mil, ‰) and is normalized to the 

per mil scale (Gonfiantini, 1984; Hut, 1987; Coplen, 1988 and 

1994).

Dissolved-gas concentrations in ground water can change 

according to gas inputs from atmospheric and chemical 

sources and reduction/oxidation conditions (Plummer and 

Busenberg, 2000). Large nitrogen-gas concentrations can be 

attributed to contamination, denitrification, or fluctuating 

water levels and the absorption of entrapped gas within the 

vadose zone. Methane can indicate reduction of organic compounds, and carbon dioxide can indicate biodegradation. As a 

conservative gas, argon can be used to view changes to 

nitrogen when dissolved nitrogen compounds are undergoing 

reduction or oxidation. Oxygen in the atmosphere and in the 

unsaturated zone is dissolved in precipitation and recharge 

water and can be consumed by oxidizable material, principally 

organic matter and reduced inorganic minerals encountered 

along the flow path.

Contaminant Monitoring

Because of current (2004) and historical military, grazing, 

and agricultural land uses at the Range, ground water was analyzed for pesticides, explosives, volatile organic compounds, 

semivolatile organic compounds, total organic halogens, and 

perchlorate (table 2). Because the historical use of pesticides is 

undocumented, water from all wells was analyzed for 21 organochlorine and 27 organophosphorous pesticides. Water from 

all wells was analyzed for nitrogen-based explosives because of 

the use of live ordnance at the Range from 1952 to 1969. Water 

from wells in the Impact Area was analyzed for volatile organic 

compounds, semivolatile organic compounds, and total organic 

halogens because of past activities at the SWMU’s and AOC’s. 

Because of the recent detection of perchlorate, an oxidizing 

agent in rocket fuel, at military installations across the Nation, 

one sample from each well was analyzed for this compound.

Quality Assurance and Quality Control

Quality-assurance procedures were used for water-level 

measurements and for collection and field processing of waterquality samples to ensure the accuracy of the data and to assist 

in interpretation of the data. Water levels in wells with dedicated submersible pumps were measured repeatedly to ensure 

that water levels were stable and not recovering from recent 

pumping. The portable submersible pump used to collect waterquality samples was decontaminated prior to use in each well. 

For all wells except the 4-foot diameter, hand-dug well 

(MWQ 9), a minimum of one well volume was pumped prior to 

sample collection. During purging, field values of specific conductance, pH, dissolved oxygen, turbidity, and water temperature were monitored and allowed to stabilize prior to sample 

collection. All open casing wells pumped dry following one 

well volume extraction. Wells with dedicated pumps were 

purged for three well volumes because of the availability of 

water in the surrounding formation. MWQ 9 could not be 

purged a full well volume because of the well’s large diameter; 

all results for MWQ 9 are qualified for possible non-representation of ground water in the surrounding formation. 

Four types of quality-control samples were collected in the 

field as part of this study: replicates, field-equipment blanks, 

matrix spikes, and trip blanks. In addition to field quality-control samples, Severn Trent Laboratories used internal qualityassurance practices to provide quality control of analytical procedures. These practices included laboratory-control sample 

analysis and method-blank sample analysis. For comparison of 

quality-control sample results, data-quality objectives defined 

by Severn Trent Laboratory were used to evaluate the quality of 

the laboratory results (supplemental information located in the 

back of the report). All water-quality concentrations determined 

to have quality-control issues are qualified in the results tables 

in the “Ground-Water Quality” section.
10 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Water-quality data were examined for concentration bias 

because suspended particulates in water samples may have produced outlier concentrations in the well data sets (supplemental 

information). With unfiltered samples, there is a potential for 

suspended particulates in well water to bias valid samples of 

formation water because of accumulated concentrations on particles and (or) matrix interference. Regular pumping of the dedicated pumps for the stock-tank system provided those wells 

with sufficient purging to keep the water clear of particulates. 

Samples collected with the portable submersible pump had the 

potential to include particulates without sufficient purging. By 

examining data-set outliers and turbidity, samples that were 

likely influenced by particulates were identified and qualified 

accordingly. 

Acknowledgments

The cooperation of many individuals and organizations 

was essential for completion of this study. The authors 

acknowledge the support and help of the Pollution Prevention 

and Natural Resource Units of the Cannon AFB Engineering 

Department. Dennis Timmons, Don White, Peter Zamie, and 

Rick Crow of Cannon AFB initiated this study and provided 

useful insight for completion of the study goals. The efforts of 

Kerry Hubbell and Rick Chandler in providing guidance and 

escorts across the Range and Dan Cass for his help in surveying 

and mapping the study area monitoring wells are appreciated. 

The authors also acknowledge the support of Gary Warren of 

Range Operations for access to the Impact Area and Sara 

Caldwell of the USGS for her participation in sample collection 

and data analysis.

Ground-Water Hydrology

During installation of wells MWQ 1 and 2, drill cuttings 

indicated a thin soil layer underlain by a thin caliche layer followed by various layers of sand and silt (fig. 3). A saturated 

gravel layer was encountered between 125 and 130 ft below 

land surface and is underlain by a thin layer of sand, likely the 

base of the Ogallala Formation. The altitude of the gravel layer 

is consistent with the altitude of total depths in most windmills, 

stock wells, and monitoring wells that were installed in and 

around the Range to pump water from the unconfined aquifer. 

Underlying the gravel and thin sand layer is a clay layer about 

50 ft thick, which grades into clay with various percentages of 

sand and silt with some sand stringers. A 2-ft-thick wateryielding zone was present in the clay, sand, and silt deposits of 

the Chinle Formation at about 235 ft below land surface.

Drilling logs on file with the New Mexico Office of the 

State Engineer indicate a similar lithology in other areas of the 

Range not dominated by the Mesa. The top of the unconfined 

aquifer is typically between 80 and 150 ft below land surface, 

aquifer thickness ranges from 5 to 40 ft, and the aquifer is typically underlain by a clay layer. Drilling at most sites did not 

proceed into this clay layer. This clay layer defines the base of 

the Ogallala Formation at the Range, which represents the base 

of the unconfined aquifer (fig. 4). 

Ground-Water Age

Ground-water ages, as determined by CFC age-dating 

analysis, ranged from 10 to 55 years across the Range. Younger 

ground water (less than 25 years) generally was found near the 

Mesa and in the Impact Area, whereas older ground water (generally 40 to 55 years) was typically found in the Portales Valley 

(fig. 5). Water from MWQ 11, atop the Mesa, was slightly older 

(30 years) than water from nearby MWQ 10 (20 years), and 

water from MWQ 4, in the northern part of the study area, was 

younger (20 years) than nearby wells (45 to 55 years) in the 

Portales Valley. MWQ 4 is located in the sand deposits of the 

Blackwater Draw Formation, which may have aided local 

recharge.

Local CFC inputs may have elevated CFC concentrations 

(concentrations of one or two of the three CFC compounds were 

larger than those found in the atmosphere during the history of 

CFC production) in ground water in the Impact Area, indicating 

that CFC concentrations were possibly a mixture of atmospheric sources and local sources from Range activities. Elevated CFC concentrations reduced the validity of ground-water 

ages for samples from wells MWQ 8 and 14-17. Age determinations in these wells were based on one or two CFC compounds instead of the three compounds. Elevated CFC concentrations may indicate that prior land uses affected water quality 

in the Impact Area.

The young age (25 years) of ground water in well MWQ 2 

in the Chinle Formation is unusual because of similar groundwater ages in the unconfined aquifer in the Impact Area and the 

older water from the regional flow system in the Portales 

Valley. Deeper ground water is typically older because it is 

farther from recharge areas than younger ground water that is 

recharged in shallower deposits. Analysis of water from 

MWQ 2 did not indicate elevated CFC concentrations but did 

indicate possible mixing of different ground waters. This possible mixing suggests a connection between the unconfined aquifer in the Ogallala Formation and the deeper, confined aquifer 

in the Chinle Formation or similar recharge areas.

Ground-Water Levels

Water levels in the unconfined aquifer declined from 1962 

to 2003 at the Range. This decrease corresponds with declining 

water levels found across the Southern High Plains aquifer 

(McGuire and others, 2003). Wells shown in figure 6 are representative of the data available for water-level declines at the 

Range during this period. Ground-water levels in wells with 

available data (13 wells) declined from about 1 ft (MWQ 12) to 

18 ft (MWQ 3) during varying periods of record from 1962 to 

2003. The water level in well MWQ 12 fluctuated about 2 ft and 

declined about 1 ft from 1975 to 2003 (fig. 6). Well MWQ 12 is 

located adjacent to and may be influenced by channel recharge 

from an ephemeral tributary of the Cañada del Tule.
Ground-Water Hydrology 11

Figure 3. Lithology and hydrogeology of Ogallala and Chinle Formations at well MWQ 2, Melrose Air Force Range.

LITHOLOGIC 

LITHOL

DESCRIPTION

OGY

HYDROGEOLOGY

GEOLOGY

WELL

CONSTRUCTION

ALTITUDE

(NAVD 88)

Soil and caliche

Sand with silt, very fine grained 

Sand with silt and some 

granules and small pebbles 

Gravel with sand and silt 

overlying sand layer 

Clay

Clay with sand and silt,

very fine grained

Clay with sand stringers, 

very fine grained 

Clay with sand and silt

Sand with silt and clay

Clay with sand and silt

Clay with silt

Sand with silt

Clay with silt

Unsaturated zone 

Unconfined aquifer

Confining unit

Confined aquifer 

Confining unit

Ogallala 

Formation of 

Tertiary age

Upper unit of 

Chinle 

Formation of 

Triassic age

4,300

4,325

4,350

4,375

4,400

4,425

4,450

4,475

4,500

4,525

4,550

4,575

4,600

4,625

4,650

4,675

 0

25

50

75

100

125

150

175

200

225

250

275

300

325

350

375

400

DEPTH BELOW 

LAND SURFACE

Water level in 

 March 2003

Not the bottom of the formation

Confined

Unconfined

Screened 

interval

Unconformity

Backfill
12 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Figure 4. Altitude of the base of the Ogallala Formation at Melrose Air Force Range.

4,200

4,250

4,300

4,150

4,350

4,100

4,400

4,097

4,072

4,066

4,089

4,126

4,182

4,210

4,316

4,111

4,279 4,100

4,136

4,148

4,403

4,155

4,174

4,142

4,180

4,145

4,133 4,164

4,159

4,135

4,139

4,155

4,168

4,154

4,485

4,403

Well with geologic log on record with New Mexico Office of the State Engineer—Altitude of the

 base of the Ogallala Formation. Vertical coordinate information is referenced to NAVD 88

Line of equal depth of base of the Ogallala Formation—Dashed where approximate. Interval is 50 feet.

 Vertical coordinate information is referenced to NAVD 88

4,400

MILES

KILOMETERS

0

024

Base provided by Cannon Air Force Base 2 4

EXPLANATION

County Road County Road

Krider Road Krider Road

Main Access Road Main Access Road

County Road

Krider Road

Main Access Road

Impact Area Impact Area

Melrose Air Force R Melrose Air Force Range

Impact Area

Melrose Air Force Range

103o50’ 103o45’ 103o40’

34o

20’

34o

15’
Ground-Water Hydrology 13

Figure 5. Age of ground water at Melrose Air Force Range, December 2002.

MWQ 17

ND

MWQ 3

55

MWQ 2

25

MWQ 8

15*

MWQ 7

40

MWQ 6

50

MWQ 14

15*

MWQ 16

25*

MWQ 15

20*

MWQ 13

15

MWQ 12

15

MWQ 11

30

MWQ 10

20

MWQ 4

20

MWQ 5

45

MILES

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0

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EXPLANATION

County Road County Road

Krider Road Krider Road

Main Access Road Main Access Road

County Road

Krider Road

Main Access Road

Impact Area Impact Area

Melrose Air Force R Melrose Air Force Range

Impact Area

Melrose Air Force Range

34o

20’

34o

15’

Age not determined—Chlorofluorocarbon concentration elevated for all three

 chlorofluorocarbon compounds

ND

Elevated chlorofluorocarbon concentration for one or two chlorofluorocarbon compounds

Well completed in the Ogallala Formation—Top characters are well number;

 bottom number is median ground-water age, in years

MWQ 11

30

Well completed in the Chinle Formation—Top characters are well number;

 bottom number is median ground-water age, in years

MWQ 2

25
14 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Figure 6. Depth to water from land surface in selected wells at Melrose Air Force Range, 1962-2003.

57

54

51

48

45

42

125

120

115

110

105

100

73

71

69

67

65

63

45

43

41

39

37

35

33

31

50

46

42

38

34

58

56

54

52

50

48

MWL 3

MWQ 3

MWL 7

MWL 9

MWQ 10

MWQ 12

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

DEPTH TO WATER, IN FEET BELOW LAND SURFACE
Ground-Water Quality 15

During the study period, water levels varied less than 1 ft 

from minimum to maximum depth to water in 21 of the 28 

wells. Examples of water-level variations during the study 

period are shown in figure 7. Water levels in wells MWQ 4, 10, 

and 11 and MWL 1, 5, 7, and 10 ranged from 1.11 (MWL 7) to 

5.27 ft (MWQ 11). The water level in MWQ 11 may have been 

influenced by pumping, and a slow recovery was not detected 

during a water-level measurement.

Potentiometric Surfaces

The median potentiometric surface of ground water in the 

Chinle Formation at well MWQ 2 was about 4,171 ft above 

NAVD 88 and was higher than the potentiometric surface of 

wells in the unconfined aquifer in the immediate area. Upward 

leakage of water from the Chinle Formation to the Ogallala 

Formation is inhibited at well MWQ 2 because the potentiometric surface in MWQ 1 was about 10 ft lower than the potentiometric surface of MWQ 2. 

Locally, the confined aquifer of the Chinle Formation 

reflects geologic structure (bed dips to the northeast) as indicated by similar zones found in deep boreholes drilled for oil 

and gas exploration in the Impact Area (New Mexico Office of 

the State Engineer, written commun., 2003). If the potentiometric surface of the deeper, confined aquifer of the Chinle Formation parallels the dip of the bed, the potentiometric surface of 

the confined aquifer is likely higher to the southwest, which 

could facilitate upward leakage over a larger area of the Range 

if the clay layer separating the aquifers is discontinuous or 

permeable (fig. 3). In parts of Roosevelt County, the potentiometric surface of the confined aquifer of the Chinle Formation 

is higher than the potentiometric surface of the Southern High 

Plains aquifer; thus, it is assumed that upward leakage to the 

unconfined aquifer is occurring (Nativ, 1988).

Ground-Water Flow

Water-level contours for the unconfined aquifer indicate 

ground water flowing predominantly northeast from the Mesa 

to the Portales Valley (fig. 8) in the Southern High Plains aquifer. The change in flow direction in the unconfined aquifer in 

the Portales Valley indicates two flow systems—local and 

regional. The local flow system is the ground water in the southwest part of the Range that flows northeast from the Mesa, and 

the regional flow system is in the Portales Valley where ground 

water flows east to southeast across the northern part of the 

Range.

 Ground-water flow is southeast and east in the Portales 

Valley, which corresponds with previously mapped groundwater flow (Hart and McAda, 1985). Direction of ground-water 

flow is a reflection of the contact between the Ogallala and 

Chinle Formations. This contact determines ground-water 

gradient and saturated thickness of the unconfined aquifer in the 

Ogallala Formation. The local flow-system gradient is about 

1.3 percent, and the regional flow-system gradient is about 

0.1 percent. Saturated thickness of the aquifer increases as the 

local flow system merges with the regional flow system.

Ground-Water Quality

Prior to this study, water-quality sampling at the Range 

had been conducted only at the SWMU’s and AOC’s. Because 

of the age of ground water in the unconfined aquifer (15 to 55 

years), water quality was not expected to substantially vary 

during the study period. Analysis of the water-quality data indicated some temporal variation, but because of the whole-water 

sampling and potential errors in field and laboratory processes, 

the temporal variation was not considered significant for most 

constituents. 

General Physical and Chemical Properties

Median specific conductance and concentrations of dissolved solids in ground water at the Range varied widely 

(table 3 and fig. 9) and can be separated into three distinct 

groups. The first group includes wells in the regional flow system (MWQ 3–7), which yielded ground water with the smallest 

median specific-conductance values, ranging from 564 to 

792 μS/cm, and the smallest median concentrations of dissolved solids, ranging from 370 to 525 mg/L. Water from well 

MWQ 10, located atop the Mesa, had a median specific conductance of 635 μS/cm and a median concentration of dissolved 

solids of 380 mg/L, which is similar to the regional flow system 

(MWQ 3-7). In the second group, samples collected from wells 

MWQ 9 and 11 near the Mesa and from wells MWQ 12 and 13 

near ephemeral streams in the southern part of the Range had 

larger specific-conductance values (1,100 to 1,436 μS/cm) and 

larger concentrations of dissolved solids (548 to 860 mg/L). 

Samples from a third group of wells with similar water quality 

included wells near and in the Impact Area (MWQ 14-17) and 

a well located west of the Impact Area (MWQ 8). Water from 

this group of wells had the largest median specific-conductance 

values, ranging from 2,575 to 10,665 μS/cm, and the largest 

median concentrations of dissolved solids, ranging from 1,700 

to 6,200 mg/L. 

The median concentration of dissolved solids (6,300 

mg/L) in water from the Chinle Formation (MWQ 2) was comparable to the median concentrations in water from wells in the 

unconfined aquifer in the Impact Area, particularly well MWQ 

16. Concentrations of dissolved solids varied substantially 

during the study period in water from wells MWQ 2 (5,260 to 

7,700 mg/L) and MWQ 16 (1,870 to 7,400 mg/L) (table 3). 

Water in the confined aquifer (MWQ 2) was the warmest 

(27.2 oC) followed by water in well MWQ 16 in the unconfined 

aquifer (22.7 oC). Water temperatures in wells near and in the 

Impact Area generally were higher than water temperatures in 

wells near the Mesa and in the regional flow system. Similar 

water temperatures and concentrations of dissolved solids in 

water from the unconfined aquifer and the deeper, confined 

aquifer in the Impact Area indicate a possible connection 

between the Chinle Formation and the Ogallala Formation. This 

possible connection may be allowing upward leakage from the 

deeper, confined aquifer to the unconfined aquifer in the local 

flow system.
16 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Figure 7. Depth to water from land surface in selected wells at Melrose Air Force Range, 2002-03.

116

114

112

110

108

106

15

13

11

9

7

5

76

74

72

70

68

66

110

109

108

50

46

48

44

42

40

50

46

48

44

42

40

MWL 1

MWL 5

MWL 7

MWQ 8

MWL 10

MWQ 10

3/1/2002 6/9/2002 9/17/2002 12/26/2002 4/5/2003

Missing value

DEPTH TO WATER, IN FEET BELOW LAND SURFACE
Ground-Water Quality 17

Figure 8. Median ground-water altitudes at Melrose Air Force Range, 2002-03.

4,200

4,250

4,3004,300

4,150

4,350

4,400

4,450

4,500

4,200

4,250

4,300

4,150

4,350

4,400

4,450

4,500

MWQ 2

4,171

MWQ 9

4,451

MWQ 7

4,194

MWL 1

4,129

MWL 5

4,184

MWQ 4

4,180

MWL 4

4,171

MWQ 5

4,178 MWL 7

4,184

MWL 3

4,169

MWL 2

4,165

MWQ 3

4,147

MWQ 8

4,360

MWL 9

4,198

MWQ 6

4,188 MWL 8

4,188

MWL 6

4,188

MWQ 17

4,201

MWQ 13

4,129

MWQ 12

4,351

MWL 12

4,404

MWQ 11

4,542

MWQ 10

4,595

MWL 10

4,531

MWQ 14

4,316

MWQ 16

4,176

MWQ 15

4,251

MWQ 2

4,171

MWQ 9

4,451

MWQ 7

4,194

MWL 1

4,129

MWL 5

4,184

MWQ 4

4,180

MWL 4

4,171

MWQ 5

4,178 MWL 7

4,184

MWL 3

4,169

MWL 2

4,165

MWQ 3

4,147

MWQ 8

4,360

MWL 9

4,198

MWQ 6

4,188 MWL 8

4,188

MWL 6

4,188

MWQ 17

4,201

MWQ 13

4,129

MWQ 12

4,351

MWL 12

4,404

MWL 11

4,522

MWQ 11

4,542

MWQ 10

4,595

MWL 10

4,531

MWQ 14

4,316

MWQ 16

4,176

MWQ 15

4,251

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EXPLANATION

County Road County Road

Krider Road Krider Road

Main Access Road Main Access Road

County Road

Krider Road

Main Access Road

Impact Area Impact Area

Melrose Air Force R Melrose Air Force Range

Impact Area

Melrose Air Force Range

103o50’ 103o45’ 103o40’

34o

20’

34o

15’

Well completed in the Ogallala Formation—Top characters are well number; bottom number is altitude of

 water level, in feet above NAVD 88

Southern High Plains aquifer water-level contour—Shows median altitude of water table, 2002-03.

 Dashed where approximate. Interval is 50 feet. Vertical coordinate information is referenced to NAVD 88

Generalized direction of ground-water flow

MWL 12

4,404

Well completed in the Chinle Formation—Top characters are well number; bottom number is altitude of

 water level, in feet above NAVD 88 

MWQ 2

4,171

4,500
18 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Table 3. Median concentrations and ranges of general physical and chemical properties for ground-water samples collected at 

Melrose Air Force Range, June 2002 to March 2003.

[All wells, except MWQ 2, completed in the Ogallala Formation; μS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L, milligrams per liter; NA, not 

available; NR, concentration is potentially non-representative of the concentration in the surrounding formation because of well construction; V, concentrations 

lack validity because of potential contamination during sample collection and (or) laboratory analysis; O, outlier(s) removed from data set prior to statistical 

analysis; <, less than]

Well number

(fig. 1)

Specific conductance

(μS/cm)

pH

(standard units)

Oxygen, dissolved

(mg/L)

Temperature

(degrees Celsius)

Median Range Median Range Median Range Median Range

1MWQ 2 NA NA 7.8 7.6-7.9 0.6 0.4-1.3 27.2 23.0-31.4

MWQ 3 792 782-803 7.8 7.6-8.2 6.7 2.9-7.1 18.9 17.4-19.2

MWQ 4 584 568-599 7.4 7.3-7.6 7.2 5.5-8.1 15.7 15.1-16.9

MWQ 5 655 631-674 7.5 7.3-7.5 5.1 2.4-7.7 17.9 17.0-18.0

MWQ 6 564 556-577 7.5 6.9-7.6 5.5 4.4-8.1 18.5 17.5-17.5

MWQ 7 769 756-850 7.5 7.3-7.9 5.2 0.0-7.6 18.2 17.4-18.8

MWQ 8 3,190 3,130-3,380 7.6 7.4-7.6 2.5 2.3-3.2 18.2 16.9-20.3

MWQ 9 1,100 NR 1,033-1,173 7.7 NR 7.1-8.2 0.3 NR 0.2-0.9 15.7 NR 14.5-17.3

MWQ 10 635 602-658 7.2 7.1-7.7 7.6 4.4-8.8 17.7 15.0-19.6

MWQ 11 1,284 949-1,623 7.6 7.4-7.9 4.4 2.3-5.3 18.8 17.7-19.7

MWQ 12 1,328 1,210-1,380 7.4 7.4-7.7 6.0 4.0-8.5 18.1 16.1-19.9

MWQ 13 1,436 1,400-1,480 7.8 7.8-8.0 5.3 3.3-7.6 20.5 19.7-21.9

MWQ 14 3,755 3,680-3,880 7.8 7.6-8.0 3.5 1.5-6.3 18.7 16.5-20.5

MWQ 15 7,520 7,270-8,700 7.6 6.9-7.7 1.1 0.2-1.7 20.4 19.6-22.8

MWQ 16 10,665 8,670-13,800 7.5 6.9-7.6 5.6 3.5-6.8 22.7 19.3-23.5

MWQ 17 2,575 1,900-2,740 7.6 7.1-7.8 6.2 4.5-7.8 19.9 17.8-22.0

Well number 

(fig. 1)

Solids, residue at 180 deg C,

dissolved (mg/L)

Alkalinity, lab

(mg/L as CaCO3)

Cyanide, total

(mg/L)

Sulfide, total

(mg/L)

Median Range Median Range Median Range Median Range

1

MWQ 2 6,300 5,260-7,700 83 V 69-91 0.0043 0.0009-0.0050 <0.97 <0.97

MWQ 3 470 460-502 153 150-160 0.0037 0.0025-0.0075 <0.97 <0.97

MWQ 4 370 360-371 190 180-190 0.0042 0.0012-0.0049 <0.97 <0.97

MWQ 5 435 430-452 170 170-174 0.0045 0.0011-0.0058 <0.97 <0.97

MWQ 6 375 370-390 160 159-160 0.0046 0.0012-0.0067 <0.97 <0.97

MWQ 7 525 480-550 150 150-152 0.0024 0.0010-0.0040 <0.97 <0.97

MWQ 8 1,900 1,560-2,000 235 V 192-240 0.0034 0.0009-0.0038 <0.97 <0.97

MWQ 9 548 NR 540-570 536 NR, V 530-550 0.0032 NR 0.0010-0.0094 <0.97 NR <0.97-4.5

MWQ 10 380 378-390 229 220-250 0.0024 0.0009-0.0040 <0.97 <0.97

MWQ 11 755 545-960 185 170-218 0.0023 0.0010-0.0036 <0.97 <0.97

MWQ 12 860 797-880 280 V 280-282 0.0022 0.0004-0.0027 <0.97 <0.97

MWQ 13 804 780-830 208 V 200-210 0.0027 0.0008-0.0035 <0.97 <0.97

MWQ 14 2,390 2,300-2,500 142 V 130-150 0.0021 0.0010-0.0044 <0.97 <0.97

MWQ 15 5,000 4,700-5,000 140 V 132-150 0.0024 0.0014-0.0050 <0.97 <0.97

MWQ 16 6,200 1,870-7,400 49 V 40-60 0.0034 0.0010-0.0054 <0.97 <0.97

MWQ 17 1,700 O 1,100-1,800 145 V 100-158 0.0030 0.0015-0.0057 <0.97 <0.97

1Well MWQ 2 completed in the Chinle Formation.
Ground-Water Quality 19

Figure 9. Median specific-conductance values and dissolved-solids concentrations in ground water at Melrose Air Force 

Range, 2002-03.

MWQ 9

1,100

548

MWQ 17

2,575

1,700

MWQ 3

792

470

MWQ 2

NA

6,300

MWQ 8

3,190

1,900

MWQ 7

769

525

MWQ 6

564

375

MWQ 14

3,755

2,390

MWQ 16

10,665

6,200

MWQ 15

7,520

5,000

MWQ 13

1,436

804

MWQ 12

1,328

860

MWQ 11

1,284

755

MWQ 10

635

380

MWQ 4

584

370

MWQ 5

655

435

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County Road County Road

Krider Road Krider Road

Main Access Road Main Access Road

County Road

Krider Road

Main Access Road

Impact Area Impact Area

Melrose Air Force R Melrose Air Force Range

Impact Area

Melrose Air Force Range

103o50’ 103o45’ 103o40’

34o

20’

34o

15’

Well—Top characters are well number; middle number is the median specific conductance, in

 microsiemens per centimeter at 25 degrees Celsius; and bottom number is the median

 dissolved-solids concentration, in milligrams per liter

Well completed in the Ogallala Formation

MWQ 11

1,284

755

Well completed in the Chinle Formation

Hand-dug well with open-wall construction, completed in the Ogallala Formation

NA Not available
20 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Major Ions

As with specific conductance and dissolved solids, water 

from wells across the Range can be grouped into areas of similar major ion composition (table 4 and fig. 10). Using Back’s 

(1961) classification diagram, water from wells MWQ 9 and 10 

(near and on the Mesa) and water from wells MWQ 4-6 in the 

regional flow system was a mixed cation-bicarbonate type. 

Water from wells MWQ 11 and 13 along the southern boundary 

of the Range was a sodium-mixed anion type, and water from 

wells in and near the Impact Area (MWQ 8 and 14-17 and the 

deeper well MWQ 2) was a sodium-chloride type. Water from 

the deeper, confined aquifer in well MWQ 2 had similar ion 

characteristics as water in the unconfined aquifer at well 

MWQ 16 (fig. 10). Water from wells MWQ 3, 7, and 12 was of 

no distinct type.

A mixing pattern of source waters in the direction of 

ground-water flow can be demonstrated by ion concentrations 

in water from a line of wells (MWQ 10, 9, 14-17, and 3) that 

extends northeastward from the Mesa (predominant flow direction of the local flow system) (table 4). Mixed cation-bicarbonate water with small ion concentrations flows from the Mesa 

near MWQ 9 and 10 through the Impact Area at wells MWQ 

14-17, where another source of ground water increases ion concentrations and the water changes to a sodium-chloride type. As 

water in the local flow system enters the regional flow system 

near well MWQ 3, the water is of no distinct type and ion concentrations decrease. 

Median sodium and chloride concentrations in ground 

water at the Range can be separated into the same groups as 

observed with specific conductance and dissolved solids 

(fig. 11). Concentrations in water from well MWQ 10 were the 

smallest followed by concentrations in the regional flow system 

(MWQ 4-7). Concentrations increased at wells MWQ 11-13 at 

the southern boundary of the Range. Concentrations further 

increased in water from wells MWQ 8, 14, and 17, followed by 

the largest concentrations in water from wells MWQ 15, 16, 

and 2. This increase in sodium and chloride concentrations is 

likely indicative of ground water mixing with another source of 

water that increases ion concentrations as water flows from the 

Mesa through the Impact Area.

Nutrients, Organic Carbon, and Dissolved Gases

The spatial pattern observed with other constituents was 

not evident with nutrients and organic carbon concentrations 

(table 5). All median nitrogen as ammonia concentrations were 

less than 0.40 mg/L except for well MWQ 9 (25.0 mg/L), which 

was potentially not representative of the surrounding formation 

because of the well’s open-wall construction. Median nitrogen 

as nitrate-nitrite concentrations ranged from 0.01 mg/L 

(MWQ 9) to 11.2 mg/L (MWQ 10). Orthophosphate concentrations were less than the method detection limit in all samples 

except for MWQ 9 (2.0 mg/L). Median phosphorous concentrations ranged from 0.01 mg/L (MWQ 16) to 2.9 mg/L (MWQ 9). 

All median organic carbon concentrations were less than 

2.00 mg/L except for wells MWQ 9 (12 mg/L) and MWQ 15 

(6.5 mg/L). Water from well MWQ 15 may have been influenced by past land use (MA02).

Ground-water samples were analyzed for dissolved gases 

to examine changes across the Range according to gas inputs 

from the atmosphere, chemical sources, and reduction/oxidation conditions. Methane was detected in water from wells 

MWQ 2, 6, 12, and 14-16 (table 6). The presence of methane 

likely indicates methane reduction in ground water in the Chinle 

Formation (MWQ 2) and in ground water in the Ogallala Formation in an agricultural area (MWQ 6), in an area influenced 

by cattle (MWQ 12), and in the Impact Area (MWQ 14-16). 

Carbon dioxide, nitrogen, and oxygen gas concentrations 

varied across the Range (fig. 12). Concentrations of carbon 

dioxide, nitrogen, and oxygen were similar in samples from 

wells in the regional flow system (MWQ 3-7), ranging from 

4.487 to 8.746 mg/L for carbon dioxide, 15.867 to 18.983 mg/L 

for nitrogen, and 5.819 to 7.004 mg/L for oxygen. Nitrogen concentrations in water from wells MWQ 11-13 in the southern part 

of the Range were similar, ranging from 13.915 to 14.569 mg/L. 

Oxygen concentrations were similar in water from wells 

MWQ 2 (1.535 mg/L), MWQ 8 (1.981 mg/L), and MWQ 15 

(1.634 mg/L). Nitrogen concentrations were largest in water 

from MWQ 14 (22.829 mg/L) and MWQ 15 (23.442 mg/L). 

Small oxygen and large nitrogen concentrations in water from 

well MWQ 15 may be indicative of reduction.

Trace Elements

Trace element analysis indicated limited variability across 

the Range except for aluminum, barium, chromium, manganese, molybdenum, selenium, vanadium, and zinc (table 7). 

Aluminum, chromium, and zinc likely were influenced by field 

and laboratory procedures, as indicated by associated qualifiers 

and large range of values at each site. 

Median barium concentrations ranged from 15 to 135 μg/L; 

the largest concentrations were in water from wells MWQ 9 

(135 μg/L) and MWQ 10 (125 μg/L). Barium in water from well 

MWQ 2 was large (81 μg/L) relative to the remaining 13 wells 

(table 7), but the large range of values (32-130 μg/L) in water 

from MWQ 2 indicates a likely influence from field and laboratory procedures or possibly a mixing of source waters. 

The large range of manganese concentrations across the 

Range may have been a result of dissolved-oxygen concentrations and oxidation/reduction processes. The largest concentrations of manganese (table 7) were found in water with the 

smallest dissolved-oxygen concentrations (MWQ 2 and 9, 

tables 3 and 6). Manganese is a predominant participant in 

reduction/oxidation processes, and manganese oxides are typically solids or colloids (insoluble) that may release soluble 

manganese to water under anaerobic conditions (Stumm and 

Morgan, 1981). Additionally, the smallest median concentrations of nitrogen as nitrate-nitrite were in water from wells 

MWQ 2 (0.02 mg/L) and MWQ 9 (0.01 mg/L), and the largest 

median concentrations of nitrogen as ammonia were in water 

from MWQ 2 (0.335 mg/L) and MWQ 9 (25 mg/L) (table 5). 

The small nitrogen as nitrate-nitrite concentrations and large 

nitrogen as ammonia concentrations also are indicative of 

reduction and anaerobic conditions. 
Ground-Water Quality 21

Table 4. Medians and ranges of major ion concentrations for ground-water samples collected at Melrose Air Force Range, June 2002 

to March 2003.

[All wells, except MWQ 2, completed in the Ogallala Formation; mg/L, milligrams per liter; V, concentrations lack validity because of potential contamination 

during sample collection and (or) laboratory analysis; NR, concentration is potentially non-representative of the concentration in the surrounding formation 

because of well construction]

Well number 

(fig. 1)

Calcium, total 

(mg/L as Ca)

Magnesium, total 

(mg/L as Mg)

Sodium, total 

(mg/L as Na)

Potassium, total 

(mg/L as K)

Median Range Median Range Median Range Median Range

1

MWQ 2 175 V 151-190 115 101-120 2,100 1,900-2,200 8.99 8.20-12.00

MWQ 3 28.5 27.7-33.0 32.0 30.8-34.0 80.8 78.0-87.0 5.35 4.70-6.50

MWQ 4 44.2 42.0-45.0 20.3 19.0-22.0 53.3 51.0-59.0 3.17 2.70-3.30

MWQ 5 42.2 41.0-44.0 22.8 22.0-25.0 65.7 63.0-70.0 2.72 2.40-3.20

MWQ 6 38.1 37.0-40.0 18.9 18.0-20.0 57.0 54.3-64.0 2.35 1.97-2.70

MWQ 7 58.5 53.7-62.0 25.5 23.6-27.0 74.0 68.4-77.0 2.53 2.10-2.70

MWQ 8 51.0 V 44.0-69.3 21.0 18.0-23.3 662 620-680 4.10 2.90-4.81

MWQ 9 72.0 V, NR 71.0-74.0 46.2 NR 45.0-48.0 67.5 NR 63.7-80.0 10.00 NR 9.01-10.00

MWQ 10 52.3 52.0-54.0 40.5 36.9-42.0 16.5 15.2-18 5.18 5.00-5.60

MWQ 11 50.5 24.4-73.0 43.5 21.0-61.0 155 14.9-160 7.95 5.57-9.30

MWQ 12 77.0 V 70.5-82.0 66.5 60.7-71.0 130 120-140 5.25 5.18-5.90

MWQ 13 30.0 V 29.0-32.0 55.0 51.9-59.0 185 177-200 10.40 9.7-11.00

MWQ 14 65.0 V 61.6-87.0 60.5 56.9-77.0 687 660-720 11.25 9.20-13.00

MWQ 15 111 V 100-120 69.5 55.6-83.0 1,650 1,400-1,720 8.27 7.50-8.90

MWQ 16 300 V 260-339 275 240-327 2,050 1,800-2,360 15.90 12.00-17.00

MWQ 17 57.9 V 41.0-65.0 49.9 39.0-58.0 539 320-560 7.20 4.40-8.20

Well 

number 

(fig. 1)

Bicarbonate, field,

total (mg/L as HCO3)

Sulfate, total 

(mg/L as SO4)

Chloride, total 

(mg/L as Cl)

Fluoride, total 

(mg/L as F)

Bromide, total 

(mg/L as Br)

Median Range Median Range Median Range Median Range Median Range

1MWQ 2 100 95-104 1,150 1,050-1,200 2,900 2,550-3,300 0.54 0.07-1.10 8.05 7.20-14.0

MWQ 3 181 181-181 136 130-140 59.9 56.0-61.0 1.95 1.90-2.00 0.48 0.44-0.50

MWQ 4 233 222-244 57.0 55.7-59.0 18.5 18.0-19.7 1.80 1.80-1.90 0.26 0.22-0.40

MWQ 5 209 203-214 98.5 92.0-102 22.0 21.0-23.0 2.40 2.40-2.50 0.26 0.16-0.3

MWQ 6 191 184-197 81.0 75.0-87.0 15.5 13.0-16.9 2.65 2.60-2.90 0.34 0.16-0.50

MWQ 7 190 184-195 165 149-170 52.3 48.0-69.0 1.80 1.60-1.90 0.43 0.35-0.79

MWQ 8 285 277-292 600 492-720 445 403-560 2.50 1.60-3.30 3.25 2.4-4.00

MWQ 9 634 NR 592-675 19.6 NR 7.6-28.0 29.0 NR 23.8-33.0 4.25 NR 4.00-4.70 0.39 NR 0.25-0.44

MWQ 10 274 262-285 39.0 35.2-48.0 20.5 14.4-24.0 0.90 0.80-0.94 0.26 0.17-0.35

MWQ 11 245 242-248 190 105-230 160 70.5-220 2.00 1.50-2.40 1.08 0.50-1.40

MWQ 12 338 334-342 275 252-310 90.6 87.0-100 3.85 3.40-4.00 0.65 0.59-0.72

MWQ 13 250 244-255 158 140-160 222 210-230 4.05 3.80-4.50 1.30 1.10-1.50

MWQ 14 182 176-187 905 882-980 560 543-610 2.65 2.20-3.70 4.55 4.30-5.30

MWQ 15 149 143-154 1,795 1,600-1,800 1,500 1,300-1,520 1.85 0.08-2.60 10.10 8.80-11.1

MWQ 16 66 61-70 1,600 1,300-2,020 3,100 2,500-3,630 1.45 0.08-1.70 8.25 6.70-10.7

MWQ 17 212 197-226 587 350-640 465 290-560 2.20 1.40-2.50 1.95 1.30-2.40

1

Well MWQ 2 completed in the Chinle Formation.
22 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Figure 10. Ground-water composition at Melrose Air Force Range, 2002-03.

EXPLANATION

10 Well number (MWQ)

CALCIUM

MAGNESIUM

SODIUM PLUS POTASSIUM

CARBONATE PLUS BICARBONATE

CHLORIDE

SULFATE

SULFATE PLUS CHLORIDE

CALCIUM PLUS MAGNESIUM

10

9

4

12 3

5

7 6 11

13

16

2

1714

8

15

10

9

4

12

3 5

7

6 11

13 16

2

17

14

8 15

10

9

4

3

5

7

6

11

13

16

2 17

14

8

15

12

PERCENTAGE, IN MILLIEQUIVALENTS

0

0

0

20

40

60

80 20

40 20

40

60

60

80

100 80

100

100

0 0

20

20 20

40

40 40

40

20

60

60 60

60

80 80

80 80

100

100

0

0

0

20

20

20

40

40

40

60

60

60

80

80 100

100

100

80

PERCENTAGE, 

IN MILLIEQUIVALENTS

PERCENTAGE, 

IN MILLIEQUIVALENTS

Note: Well MWQ 2 completed in the Chinle Formation. All other wells completed in the Ogallala Formation.
Ground-Water Quality 23Figure 11. Median sodium and chloride concentrations in ground water at Melrose Air Force Range, 2002-03. 10 100 1,000 2 3 4 5 6 7 89 2 3 4 5 6 7 89 2 3 SODIUM CONCENTRATION, IN MILLIGRAMS PER LITER

10

100

1,000

5432987654329876543298765

CHLORIDE CONCENTRATION, IN MILLIGRAMS PER LITER

2 Well number (MWQ)

MESA

3

4

5

6

7

8

9

10

11

12

13

14

15

17

2

16

SOUTHERN BOUNDARY

REGIONAL FLOW SYSTEM

IMPACT AND SURROUNDING AREAAND CHINLE FORMATION

Well MWQ 2 completed in the Chinle FormationAll other wells completed in the Ogallala Formation
24 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Table 5. Medians and ranges of nutrient and total organic carbon concentrations for ground-water samples collected at Melrose Air 

Force Range, June 2002 to March 2003.

[All wells, except MWQ 2, completed in the Ogallala Formation; mg/L, milligrams per liter; conc., concentration; DP, decreased concentration precision because 

of small concentration levels; <, less than; NR, concentration is potentially non-representative of the concentration in the surrounding formation because of well 

construction]

Well 

number 

(fig. 1)

Nitrogen, ammonia 

total (mg/L as N)

Nitrogen, nitrate-nitrite 

total (mg/L as N)

Orthophosphate, total 

(mg/L as P)

Phosphorus, total

(mg/L as P)

Carbon, organic total 

(mg/L as C)

Median Range Median Range Conc. Range Median 

(DP) Range Median (DP) Range

1MWQ 2 0.335 0.280-0.460 0.02 0.01-0.23 <0.04 <0.04 0.12 0.01-0.38 0.93 0.74-1.9

MWQ 3 0.019 0.008-0.043 0.91 0.85-0.93 <0.04 <0.04 0.05 0.03-0.12 0.45 0.14-0.69

MWQ 4 0.035 0.020-0.063 5.70 5.60-6.00 <0.04 <0.04 0.19 0.01-0.44 0.37 0.14-3.0

MWQ 5 0.040 0.020-0.087 6.25 5.90-6.50 <0.04 <0.04 0.08 0.01-0.16 0.55 0.29-0.92

MWQ 6 0.019 0.008-0.071 4.55 4.20-5.70 <0.04 <0.04 0.17 0.01-0.47 0.33 0.14-0.66

MWQ 7 0.008 0.008-0.074 1.65 1.40-1.70 <0.04 <0.04 0.03 0.01-0.28 0.65 0.14-0.70

MWQ 8 0.115 0.050-0.260 0.42 0.26-0.52 <0.04 <0.04 0.12 0.01-0.87 1.8 1.5-1.9

MWQ 9 25.0 NR 18.5-29.0 0.01 NR 0.01-0.07 2.0 NR <0.04 2.9 NR 2.5-3.1 12 NR 10-16

MWQ 10 0.035 0.020-0.500 11.2 9.9-12.0 <0.04 <0.04 0.08 0.01-0.39 0.88 0.51-1.3

MWQ 11 0.040 0.020-0.068 7.45 3.30-11.0 <0.04 <0.04 0.06 0.01-0.09 0.84 0.66-1.3

MWQ 12 0.160 0.150-0.400 1.40 1.40-1.60 <0.04 <0.04 0.03 0.01-0.17 1.1 0.75-1.5

MWQ 13 0.025 0.020-0.079 6.20 5.50-6.30 <0.04 <0.04 0.08 0.04-0.64 0.82 0.61-1.1

MWQ 14 0.045 0.020-1.10 2.15 2.10-2.30 <0.04 <0.04 0.05 0.01-0.07 0.65 0.31-0.90

MWQ 15 0.093 0.030-0.100 5.30 4.00-5.80 <0.04 <0.04 0.05 0.007-0.160 6.5 6.2-6.5

MWQ 16 0.025 0.008-0.065 0.87 0.73-1.10 <0.04 <0.04 0.01 0.007-0.03 0.32 0.14-0.72

MWQ 17 0.035 0.020-0.42 0.25 0.18-0.26 <0.04 <0.04 0.08 0.01-0.12 0.61 0.15-0.76

1

Well MWQ 2 completed in the Chinle Formation.

Table 6. Dissolved gas concentrations for ground-water samples collected at Melrose Air Force Range, December 2002.

[All wells, except MWQ 2, completed in the Ogallala Formation; mg/L, milligrams per liter]

Well number 1

(fig. 1)

Methane

(mg/L)

Carbon dioxide

(mg/L)

Nitrogen

 (mg/L)

Oxygen 

(mg/L) 

Argon

(mg/L)

2MWQ 2 0.0264 1.802 16.510 1.535 0.4746

MWQ 3 0.0000 4.487 15.867 6.084 0.5463

MWQ 4 0.0000 8.746 15.911 6.343 0.5501

MWQ 5 0.0000 7.258 17.593 6.174 0.5768

MWQ 6 0.0008 6.251 18.983 5.819 0.6021

MWQ 7 0.0000 6.872 16.226 7.004 0.5502

MWQ 8 0.0000 8.371 12.052 1.981 0.4364

MWQ 10 0.0000 16.067 19.252 8.309 0.6146

MWQ 11 0.0000 7.139 14.569 3.657 0.5271

MWQ 12 0.0121 15.622 13.915 3.896 0.5120

MWQ 13 0.0000 6.762 14.371 3.198 0.5028

MWQ 14 0.0106 3.508 22.829 3.118 0.6541

MWQ 15 0.0023 4.700 23.442 1.634 0.6558

MWQ 16 0.0028 1.676 18.290 5.217 0.5849

MWQ 17 0.0000 3.008 12.582 5.813 0.4707

1Ground water from MWQ 9 was not analyzed by the lab for dissolved gases because of its open-well construction.

2

Well MWQ 2 completed in the Chinle Formation.
Ground-Water Quality 25Figure 12. Carbon dioxide, nitrogen, and oxygen gas concentrations in ground water at Melrose Air Force Range, December 2002. MWQ 2 MWQ 3 MWQ 4 MWQ 5 MWQ 6 MWQ 7 MWQ 8 MWQ 10 MWQ 11 MWQ 12 MWQ 13 MWQ 14 MWQ 15 MWQ 16 MWQ 17

5

3025

201510

DISSOLVED GAS CONCENTRATION, IN MILLIGRAMS PER LITER

Carbon dioxide

Well MWQ 2 completed in the Chinle FormationAll other wells completed in the Ogallala Formation

NitrogenOxygen
26 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico Table 7. Medians and ranges of trace element concentrations for ground-water samples collected at Melrose Air Force Range, June 2002 to March 2003. [All wells, except MWQ 2, completed in the Ogallala Formation; μg/L, micrograms per liter; DP, decreased concentration precision because of small concentration levels; <, less than; O, outlier(s) removed from data set prior to statistical analysis; NA, not available; NR, concentration is potentially non-representative of the concentration in the surrounding formation because of well construction; V, concentrations lack validity because of potential contamination during sample collection and laboratory analysis] Well number (fig. 1) Aluminum, total (μg/L as Al) Antimony, total (μg/L as Sb) Arsenic, total (μg/L as As) Barium, total (μg/L as Ba) Beryllium, total (μg/L as Be) Cadmium, total (μg/L as Cd) Median Range Median Range Median (DP) Range Median Range Median Range Median Range

1MWQ 2 <20 O <20-21 <4 <4 <4 <4 81 32-130 <1 <1 <1 <1

MWQ 3 <20 <20-22 <4 <4 8 5-13 26 3.4-32 <1 <1 <1 <1MWQ 4 <20 <20-24 <4 <4 4 <4-7 46 1.0-46 <1 <1 <1 <1MWQ 5 <20 <20 <4 <4 6 <4-7 30 0.5-31 <1 <1 <1 <1MWQ 6 <20 <20-21 <4 <4 6 4-7 32 0.9-33 <1 <1 <1 <1MWQ 7 <20 <20-36 <4 <4 5 <4-9 31 1.9-33 <1 <1 <1 <1MWQ 8 NA O NA <4 <4 <4 <4 17 O 9.8-35 <1 <1-1.5 <1 <1MWQ 9 39 O, NR <20-110 <4 NR <4 <4 NR <4 135 NR 7.1-140 <1 NR <1-1.4 <1 NR <1MWQ 10 <20 <20-10 <4 <4 <4 <4 125 5.8-130 <1 <1-1.3 <1 <1MWQ 11 <20 <20-20 <4 <4 <4 <4 32 7.9-33 <1 <1-2.2 <1 <1MWQ 12 105 34-114 <4 <4 <4 <4 41 3.3-43 <1 <1 <1 <1MWQ 13 157 <20-280 <4 <4 6 <4-9 49 5.6-52 <1 <1 <1 <1MWQ 14 460 O 72-828 <4 <4 <4 <4 28 13-73 <1 <1 <1 <1MWQ 15 672 180-1,600 <4 <4 <4 <4 15 3.7-19 <1 <1 <1 <1MWQ 16 148 <20-280 <4 <4 <4 <4 20 2.6-24 <1 <1 <1 <1MWQ 17 2,150 O 180-2,400 <4 <4 <4 <4 56 27-100 <1 <1 <1 <1
Ground-Water Quality 27

Table 7. Medians and ranges of trace element concentrations for ground-water samples collected at Melrose Air Force Range, June 2002 to March 2003.—Continued

Well number

(fig. 1)

Chromium, total

 (μg/L as Cr)

Cobalt, total 

(μg/L as Co)

Copper, total 

(μg/L as Cu)

Iron, total 

(μg/L as Fe)

Lead, total 

(μg/L as Pb) 

Manganese, total 

(μg/L as Mn)

Median (DP) Range Median Range Median Range Median Range Median Range Median Range

1MWQ 2 <1 O <1-12 2 O <1-4 3 O 1-4 NA NA 3 1-9 355 280-500

MWQ 3 1 <1-4 <1 <1 1 <1-3 NA NA 2 1-2.4 <1 <1MWQ 4 <1 <1-1 <1 <1 3 <1-4 NA NA <2 <2 <1 <1MWQ 5 1 <1-1 <1 <1 <1 <1 NA NA <2 O <2 <1 <1MWQ 6 1 <1-3 <1 <1 <1 <1 NA NA <2 <2 2 <1-5MWQ 7 1 <1-6 <1 <1 <1 <1 NA NA <2 <2 1 <1-1MWQ 8 7 <1-24 3 <1-6 13 2-24 NA NA <2 O <2 20 O 2-110MWQ 9 1 NR <1-5 <1 NR <1 2 NR <1-7 NA NA <2 NR <2 725 NR 670-820MWQ 10 <1 <1-1 <1 <1-5 1 <1-2 NA NA <2 <2 1 <1-1MWQ 11 1 <1-1 <1 <1 3 <1-6 NA NA <2 <2 2 1-4MWQ 12 2 <1-5 <1 <1 5 4-8 NA NA <2 <2 13 9-14MWQ 13 3 <1-8 <1 <1 15 <1-18 NA NA 2 1-4 115 3-164MWQ 14 17 3-39 1 <1-6 3 1-7 NA NA 2 1-4 45 2-84MWQ 15 6 2-20 1 <1-3 3 2-5 NA NA <2 <2 63 35-72MWQ 16 7 5-13 2 <1-2 5 <1-8 NA NA <2 O <2 7 4-12MWQ 17 16 7-27 1 <1-2 3 <1-5 NA NA 3 1-4 78 20-160
28 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico Table 7. Medians and ranges of trace element concentrations for ground-water samples collected at Melrose Air Force Range, June 2002 to March 2003.—Continued Well number (fig. 1) Molybdenum, total (μg/L as Mo) Nickel, total (μg/L as Ni) Selenium, total (μg/L as Se) Silver, total (μg/L as Ag) Thallium, total (μg/L as Tl) Vanadium, total (μg/L as V) Zinc, total (μg/L as Zn) Median Range Median Range Median (DP) Range Median Range Median Range Median Range Median Range

1MWQ 2 28 18-31 13 7-34 <5 <5-6 <1 <1 <7 <7 1 O 1-6 28 V <7-120

MWQ 3 7 6-8 <2 O <2 6 <5-11 <1 <1 <7 <7 70 65-78 <7 <7-10MWQ 4 4 3-5 <2 O <2 <5 <5-6 <1 <1 <7 <7 53 49-55 12 11-19MWQ 5 4 3-5 <2 <2-3 6 <5-7 <1 <1 <7 <7 58 54-60 25 O 7-490MWQ 6 3 2-4 <2 <2-3 <5 <5-6 <1 <1 <7 <7 51 50-55 33 16-120MWQ 7 5 4-5 <2 O <2 7 <5-9 <1 <1 <7 <7 48 45-49 <7 <7-10MWQ 8 19 14-19 7 <2-22 <5 <5 <1 <1 <7 <7 8 3-17 81 O,V 50-385MWQ 9 3 NR 1-8 2 NR,O <2-2 <5 NR <5 <1 NR <1 <7 NR <7 14 NR 9-17 7 V,NR <7-18MWQ 10 5 4-5 <2 <2-2 <5 <5 <1 <1 <7 <7 33 27-37 8 <7-9MWQ 11 10 8-13 <2 O <2 22 13-23 <1 <1 <7 <7 6 1-9 27 19-51MWQ 12 11 10-12 2 O <2-3 38 34-43 <1 <1 <7 <7 19 11-22 53 V 32-150MWQ 13 11 10-12 2 O <2-3 14 7-17 <1 <1 <7 <7 52 32-65 102 V 13-115MWQ 14 28 27-28 14 5-24 25 20-26 <1 <1 <7 <7 6 4-11 17 V 9-38MWQ 15 18 14-22 <2 O <2-3 150 120-160 <1 <1 <7 <7 9 6-10 19 V <7-49MWQ 16 13 10-14 4 <2-7 24 20-25 <1 <1-4 <7 <7 6 5-6 24 V 9-30MWQ 17 7 5-8 11 3-13 <5 <5-6 <1 <1 <7 <7 14 9-20 20 V 10-24

1Well MWQ 2 completed in the Chinle Formation.
Ground-Water Quality 29

Selenium concentrations were less than or near the method 

detection limit for water from wells MWQ 2-10 and MWQ 17 

(table 7). Selenium concentrations were greater than twice the 

method detection limit for water from wells in the southern part 

of the Range (MWQ 11-13) and for most wells in the Impact 

Area (MWQ 14-16). 

Concentrations of molybdenum and vanadium in ground 

water at the Range varied the most of the trace elements. 

Molybdenum and vanadium may become mobile and migrate 

as oxides in a strongly oxidizing environment, whereas these 

trace elements typically become bound in sulfides and precipitate in strong reducing conditions (Goldschmidt, 1958). The 

distribution of molybdenum and vanadium concentrations 

across the Range suggests the possibility of different source 

waters and reduction/oxidation processes. Similar to specific 

conductance, dissolved solids, and major ions, ground water at 

the Range can be grouped either by concentrations of molybdenum or vanadium (fig. 13).

Concentrations of molybdenum in water from the regional 

flow system (MWQ 3-7) were similar, ranging from 3 to 

7 μg/L, whereas vanadium concentrations had a larger range 

(48 to 70 μg/L). Wells near and in the Impact Area (MWQ 8 and 

14-17) produced water with similar concentrations of vanadium 

(6 to 14 μg/L), but molybdenum concentrations ranged from 

7 to 28 μg/L. The molybdenum concentration (28 μg/L) and 

vanadium concentration (1 μg/L) in water from the deeper, confined aquifer of the Chinle Formation (MWQ 2) were similar to 

concentrations in water from the unconfined aquifer in the 

Impact Area. Concentrations of molybdenum and vanadium in 

water from wells near the Mesa (MWQ 9-11) and in the 

southern part of the Range (MWQ 12-13) did not exhibit a 

similar grouping as seen with the other constituents. 

Stable Isotopes

Results of stable isotope analysis (table 8) indicated variable isotopic ratios across the Range and a somewhat similar 

grouping of wells as seen with the previous constituents. In the 

regional flow system (MWQ 3-7), δD ranged from -45.79 to 

-42.78‰ and δ18O ranged from -6.22 to -5.99‰. Isotopic ratios 

in water from wells MWQ 10, 12, and 15 were similar to those 

in the regional flow system, with δD of -45.35‰, -41.97‰, and 

-45.44‰, respectively, and δ18O of -6.60‰, -6.24‰, and 

-6.47‰, respectively. Isotopic ratios in water from wells 

MWQ 8, 14, 16, and 17, near and in the Impact Area, were 

different from ratios found in the regional flow system, with δD 

ranging from -71.84 to -64.46‰ and δ18O ranging from -10.00 

to -8.77‰. Isotopic ratios were similar in water from wells 

MWQ 2 and MWQ 13, with δD ratios of -58.49‰ and 

-56.68‰, respectively, and δ18O ratios of -7.95‰ and -7.99‰, 

respectively.

The stable isotope results are an indicator of local precipitation, formation conditions, and different water sources 

(fig. 14). The slopes of fit-lines for δD and δ18O ratios for

precipitation in Clovis (Nativ, 1988) and ground water at the

Range (fig. 14) are similar and both less than 8 (enrichment of 

heavier isotopes), which is indicative of local effects. With minimal topographic relief and similar air temperatures in the area, 

recharge altitude and temperature would not be expected to play 

a substantial role in isotopic ratio differences for the local and 

regional flow system in the unconfined aquifer. The similar δD 

and δ18O ratios for water in the regional flow system (MWQ 

3-7), the local flow system on the Mesa (MWQ 10), and near an 

ephemeral stream (MWQ 12) indicate minimal change in isotope ratios because of recharge altitude or temperature (fig. 14; 

table 3). 

For ground water near and in the Impact Area, another 

source of water of different isotopic composition appears to 

have a strong influence near MWQ 8, a lessening influence 

across the Impact Area, and its weakest influence near MWQ 14 

(fig. 14). The smallest δD and δ18O ratios were in water from 

well MWQ 8, followed by water from wells MWQ 17 and 16, 

and followed then by water from wells MWQ 14 and 2. The 

smaller δD and δ18O ratios in and near the Impact Area indicate 

another source of water than what is being recharged near the 

Mesa or exists in the regional flow system. This observation is 

similar to the other water-quality constituents. Water from well 

MWQ 2 in the deeper, confined aquifer, however, does not 

appear to be the other source of water because the isotopic ratios 

in water from MWQ 2 are not similar to the isotopic ratios in 

water from MWQ 8. 

Table 8. Stable isotopic ratios for hydrogen and oxygen for 

ground-water samples collected at Melrose Air Force Range, 

December 2002.

[All wells, except MWQ 2, completed in the Ogallala Formation]

Well number

(fig. 1)

H-2/H-1 stable

isotopic ratio, per mil

(δD‰)

O-18/O-16 stable 

isotopic ratio, per mil 

(δ18O‰)

1MWQ 2 -58.49 -7.95

MWQ 3 -44.21 -5.99

MWQ 4 -42.78 -6.09

MWQ 5 -44.61 -6.19

MWQ 6 -45.79 -6.22

MWQ 7 -44.73 -6.11

MWQ 8 -71.84 -10.00

MWQ 10 -45.35 -6.60

MWQ 11 -60.87 -8.64

MWQ 12 -41.97 -6.24

MWQ 13 -56.68 -7.99

MWQ 14 -64.46 -8.77

MWQ 15 -45.44 -6.47

MWQ 16 -66.55 -9.23

MWQ 17 -66.81 -9.39

1Well MWQ 2 completed in the Chinle Formation.
30 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Figure 13. Median molybdenum and vanadium concentrations in ground water at Melrose Air Force Range, 2002-03.

Well MWQ 2 completed in the Chinle FormationAll other wells completed in the Ogallala Formation

0 10 20 30 40 50 60 70 80

VANADIUM CONCENTRATION, IN MICROGRAMS PER LITER

50

302520

1510

MOLYBDENUM CONCENTRATION, IN MICROGRAMS PER LITER

2 Well number (MWQ)

2

3

4 5

6

7

8

10

11

12 13

14

15

16

17

9

IMPACT AREA

SOUTHERN BOUNDARY

REGIONAL FLOW SYSTEM
Ground-Water Quality 31Figure 14. Hydrogen and oxygen stable isotopic ratios in ground water at Melrose Air Force Range, December 2002.

Global meteoric water lineClovis meteoric water line (Nativ, 1988)Range ground-water line

-10 -9 -8 -7 -6 -5

DELTA OXY

GEN-18, PER MIL RELATIVE TO VSMOW

-40-50

-60

-70

DELTA DEUTERIUM, PER MIL RELATIVE TO VSMOW

2 Well number (MWQ)

2

3

4

5

6

7

8

10

11

12

13

14

15

16 17
32 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

It is possible that leakage between the unconfined aquifer 

in the Ogallala Formation and confined aquifer in the Chinle 

Formation is occurring outside the Range area and creating 

ground water of mixed isotopic ratios in both the Ogallala and 

Chinle Formations. This mixed water may then be moving into 

the local flow system the Range where additional leakage is 

occurring near and in the Impact Area. Overall, the isotopic 

ratios in ground water from the Impact Area are similar to those 

historically documented for ground water in the Chinle Formation (Nativ, 1988). 

Pesticides

Analysis of ground water for pesticides resulted in no 

detections larger than method reporting limits. One detection of 

4,4’-DDT was reported for a sample from well MWQ 9 at an 

estimated concentration of 0.011 μg/L. 

Explosives

Analysis of ground water for explosive compounds 

resulted in no detections larger than method detection limits.

Volatile Organic Compounds

No volatile organic compounds were detected at concentrations greater than method reporting limits. Estimated concentrations of chlorodibromomethane (0.20 μg/L) and acetone 

(2.9 μg/L) were detected in water from wells MWQ 16 and 17, 

respectively. Chlorodibromomethane and acetone are laboratory reagents, and because of the estimated concentrations, the 

detections are considered insignificant. Methylene chloride was 

detected at estimated concentrations (less than 0.5 μg/L) in all 

samples from wells near and in the Impact Area, but this compound also was detected in trip blanks and, thus, is considered 

to be a shipping or laboratory contaminant.

Semivolatile Organic Compounds

Analysis of semivolatile organic compounds indicated no 

detections larger than method reporting limits. An estimated 

concentration of bis (2-Ethylhexyl) phthalate (4.4 μg/L) was 

detected in water well MWQ 15. Bis (2-Ethylhexyl) phthalate is 

a manufactured chemical commonly added to plastics for flexibility. This detection is likely a field or laboratory contaminant 

and is considered insignificant.

Total Organic Halogens

A total organic halogen concentration of 32 μg/L was 

detected in water from well MWQ 15. Analysis of the MWQ 15 

sample did show an analytical method interference because of 

a large chloride concentration (1,500 mg/L). Total organic 

halogen analysis provides a gross analysis for a wide range of 

compounds, including chlorinated solvents, polychlorinated 

biphenyls, and metal halides. Because of the large chloride concentration and the lack of detections of halogenated compounds 

from the semivolatile organic compound analysis, this detection 

is considered insignificant.

Perchlorate

Analysis of perchlorate indicated no detections larger than 

method detection limits in samples collected in June 2002. Perchlorate was detected at estimated concentrations in water from 

wells MWQ 14 (2.6 μg/L) and MWQ 15 (20 μg/L). Perchlorate 

analysis indicated analytical method interference because of 

large chloride concentrations in these samples. Because perchlorate was not detected in water from these wells in June 2002 

and because of the analytical method interference associated 

with large chloride concentrations, these detections are considered insignificant.

Source Waters

Because of changes in water quality from the Mesa to the 

regional flow system in the unconfined aquifer, it is likely that 

upward leakage from the deeper, confined aquifer has influenced water quality in the unconfined aquifer near and in the 

Impact Area. The spatial distribution of most water-quality 

constituents consisted of three groups: local flow system outside the Impact Area, local flow system near and in the Impact 

Area, and the regional flow system. Ground-water quality at 

the Mesa (MWQ 10) was similar to that of the regional flow 

system (MWQ 3-7), but water quality in the Impact Area 

(MWQ 14-17), located in the direction of ground-water flow in 

the unconfined aquifer between these two areas, was substantially different. 

Specific conductance, dissolved solids, water temperature, 

major ions, and the trace elements molybdenum and vanadium 

suggest that water may be leaking from the deeper, confined 

aquifer in the Chinle Formation into the unconfined aquifer in 

the Ogallala Formation and altering the water quality in the 

unconfined aquifer near and in the Impact Area. However, 

elevated CFC concentrations, nutrient concentrations, and stable isotope ratios in water near and in the Impact Area indicate 

that the deeper, confined aquifer may not be the only influence 

on water quality and that past land uses may be an influence on 

ground water near and in the Impact Area. Additionally, the 

deeper, confined aquifer likely has a variable influence near and 

in the Impact Area because various water-quality constituents 

indicated concentration variability near and in the Impact Area. 

Given the current (2004) understanding of the Range’s groundwater hydrology and water quality, the different water quality 

near and in the Impact Area cannot be attributed solely to 

upward leakage from the deeper, confined aquifer of the Chinle 

Formation, but leakage between the Ogallala and Chinle Formations is likely.
Summary 33

Summary

This report, prepared in cooperation with the U.S. Air 

Force, Cannon Air Force Base, presents the results of an investigation to characterize the ground-water hydrology and water 

quality in the Southern High Plains aquifer at Melrose Air Force 

Range. This characterization provides Cannon Air Force Base 

resource managers with reliable, baseline ground-water data 

and a broad overview of the Southern High Plains aquifer in the 

Ogallala Formation at the Range for future planning efforts to 

protect the aquifer and ensure continued operation of the Range 

and all its current (2004) activities. A 29-well monitoring network was used to determine ground-water levels (five periods 

of measurement) and collect water-quality samples (four 

periods of sample collection) from across the Range in the 

unconfined aquifer of the Ogallala Formation of Tertiary age 

and the deeper, confined aquifer of the Chinle Formation of 

Triassic age. Twenty-eight wells were used to collect data from 

the unconfined aquifer that is part of the Southern High Plains 

aquifer, and 1 well was used to collect data from the deeper, 

confined aquifer in the upper unit of the Chinle Formation. 

Water-quality samples were collected as whole (unfiltered) 

water because unfiltered water is used on the Range for agriculture and a stock-tank system.

Water levels in most wells in the Southern High Plains 

aquifer at the Range have declined from 1 to 18 ft over various 

periods from 1962 to 2003. Ground-water flow in the unconfined aquifer is dictated by the Mesa in the southwestern part of 

the Range. Ground water flows northeastward away from the 

Mesa in the local flow system and into the Portales Valley 

regional flow system where ground water then flows southeast 

and east. Younger ground water (less than 25 years) was found 

near the Mesa and in the local flow system, and older water (25 

to 55 years) was found within the regional flow system in the 

Portales Valley. The potentiometric surface of the Southern 

High Plains aquifer in the Ogallala Formation is likely lower in 

parts of the Range than the potentiometric surface of the deeper, 

confined aquifer in the upper unit of the Chinle Formation. 

Leakage between these two systems is unknown but appears 

likely.

Ground-water quality at the Range showed substantial differences in spatial distribution. Ground-water quality near the 

Mesa was similar to that of the regional flow system and also 

was fairly similar to water quality in the southern part of the 

Range. Ground water in the Impact Area was very different 

from ground water near the Mesa or in the regional flow system. 

Ground water in the Impact Area contains larger concentrations 

of dissolved solids, which probably result from upward leakage 

of ground water from the Chinle Formation.

Ground water across the Range consisted of various water 

types. Water from wells in and near the Impact Area and along 

the southern boundary of the Range generally is a sodium-chloride or sodium-mixed anion water type. Water from the Chinle 

Formation is a sodium-chloride water type. Water from some 

wells near the Mesa and water from some wells in the regional 

flow system is a mixed cation-bicarbonate water type.

A mixing pattern of source waters in the direction of 

ground-water flow was exhibited by ion concentrations in 

ground water. Mixed cation/bicarbonate ground water with 

small ion concentrations near the Mesa flows beneath the 

Impact Area where a second source of ground water or another 

influence on ground-water quality substantially increases ion 

concentrations and shifts the water type to sodium-mixed anion. 

Ground water from the local flow system then enters the 

regional flow system, where no distinct water type is present 

and ion concentrations decrease. Ion concentrations in water 

from the deeper, confined aquifer in the Chinle Formation were 

similar to ion concentrations in water from the unconfined aquifer in the Impact Area. 

Specific conductance, dissolved solids, water temperature, 

major ion concentrations, and the concentrations of molybdenum and vanadium displayed similar spatial distributions indicating upward leakage from the deeper, confined aquifer of the 

Chinle Formation to the unconfined aquifer of the Ogallala Formation in the Impact Area of the Range. Values of these constituents in ground water in the Impact Area were similar to constituent values in water from a well completed in the Chinle 

Formation. 

CFC, nutrient, and stable isotope spatial distributions were 

similar to the other constituents, but also produced spatial distribution differences that may indicate an influence of past land 

uses on ground-water quality in the Impact Area or a more complex mixing of waters between the Ogallala and Chinle Formations. CFC and nutrient concentrations were elevated in ground 

water near and in the Impact Area, and were not similar to concentrations in water from the Chinle Formation. Stable isotope 

results indicated that another source of water of different isotopic composition has a strong influence on ground water just 

west of the Impact Area with a lessening influence across the 

Impact Area, and that this source of water differs in isotopic 

ratios from water from the well in the Chinle Formation. 

Given the current (2004) understanding of the Range’s 

ground-water hydrology and water quality, the different 

ground-water quality in the Impact Area cannot be solely attributed to leakage from the Chinle Formation, although it is likely 

that leakage is occurring between the Ogallala and Chinle Formations.

Screening of potential human-induced contaminants in 

ground water across the Range indicated no significant concentrations of pesticides, explosives, volatile organic compounds, 

semivolatile organic compounds, total organic halogens, or perchlorate. Small concentrations of 4,4’-DDT (0.011 μg/L (estimated value), well MWQ 9), acetone (2.9 μg/L (estimated 

value), well MWQ 17), chlorodibromomethane (0.20 μg/L 

(estimated value), well MWQ 16), bis (2-Ethylhexyl) phthalate 

(4.4 μg/L (estimated value), well MWQ 15), total organic halogens (32 μg/L, well MWQ 15, large chloride concentration), 

and perchlorate (2.6 μg/L for well MWQ 14, 20 μg/L for well 

MWQ 15, and large chloride concentration in both wells) were 

detected, but all detections were considered insignificant 

because of estimated values, potential laboratory contamination, and (or) matrix interference from large chloride concentrations.
34 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

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Supplemental Information 37

Supplemental Information

Four types of quality-control samples were collected in the 

field as part of this study: replicates, field-equipment blanks, 

matrix spikes, and trip blanks. In addition to field quality-control samples, Severn Trent Laboratories had internal qualityassurance practices to provide quality control of analytical procedures, which included laboratory-control sample analysis and 

method-blank sample analysis. For comparison of quality-control sample results, data-quality objectives as defined by Severn 

Trent Laboratory were used to evaluate the quality of the laboratory results.

Evaluation of Quality-Control Samples

Replicate samples were evaluated for variability in environmental samples, data collection techniques, and laboratory 

precision (reproducibility). The Range replicate sample results 

indicated small relative percent differences (less than 20 percent; data-quality objectives, table S-1) among samples except 

for the constituents of phosphorus, arsenic, chromium, and selenium (table S-2). Concentrations of these constituents were 

generally less than reporting limits (estimated concentrations) 

at which precision typically decreases. All these constituents 

were qualified in the results section for decreased precision 

because of small concentrations.

Analysis of field equipment-blank samples indicated 

potential contamination for dissolved solids, alkalinity, cyanide, calcium, magnesium, sulfate, chloride, ammonia, phosphorus, organic carbon, aluminum, barium, copper, iron, manganese, and zinc. Field equipment-blank median concentrations 

for dissolved solids, cyanide, magnesium, sulfate, chloride, 

ammonia, phosphorus, organic carbon, aluminum, barium, 

copper, iron, and manganese were all smaller than reporting 

limits (data-quality objectives). Median alkalinity, calcium, and 

zinc concentrations were greater than reporting limits and did 

not meet the data-quality objectives. Results for alkalinity, calcium, and zinc in wells sampled using the portable submersible 

pump were qualified for lack of validity (bias) because of potential sample contamination during sample collection and laboratory analysis.

Matrix-spike samples were used to evaluate the ability of 

an analytical method to accurately measure a known amount of 

a constituent added to a sample. Matrix-spike-replicate samples 

were used to evaluate the precision of accurately measuring a 

known amount of a constituent added to a sample. Results of the 

matrix-spike samples collected from the Range indicated no 

bias due to matrix interference because all constituents showed 

percent recoveries (table S-2) within the recovery limits as 

specified in the data-quality objectives (table S-1). Matrixspike-replicate results indicated acceptable precision (table S-2) 

given the data-quality objectives for relative percent differences 

(table S-1).

Trip-blank analysis provided an examination of potential 

volatile organic compound exposure during handling and shipping and also potential laboratory error. Methylene chloride (a 

common laboratory contaminant) was detected in trip blanks, 

but the median concentration was smaller than the reporting 

limit and met the data-quality objective.

Analysis of laboratory-control samples provided an indication of constituent recovery error (lack of precision) for a 

spiked concentration. Laboratory-control sample analysis used 

randomly selected customer-submitted samples to perform 

matrix-spike analyses. Results of laboratory-control sample 

analysis indicated no recovery errors for any constituent; all 

median percent recoveries (table S-2) were within recovery 

limits (table S-1). 

Method-blank samples were contaminant-free samples 

that were analyzed for any potential residual contaminants in 

laboratory equipment. Results of method-blank sample analysis 

indicated potential contamination of dissolved solids, phosphorus, aluminum, and the pesticide Dieldrin (table S-2). All 

contaminant detections were smaller than reporting limits (table 

S-1) and met the data-quality objectives; therefore, potential 

contamination was not considered to be a significant factor that 

would bias environmental sample concentrations. 

Evaluation of Data Outliers

Outliers were defined as concentrations three times larger 

than the mean concentration of the remaining three data points. 

Outliers occurred in analyses for specific conductance, dissolved solids, aluminum, barium, chromium, cobalt, copper, 

iron, lead, manganese, nickel, vanadium, and zinc (table S-3). 

Wells with the greatest number of outliers corresponded to 

wells in which purging was insufficient to decrease turbidity to 

values similar to the remaining wells. Outliers were removed 

from the data sets prior to statistical analysis. Because of the 

large variability of iron concentrations in ground water from 

nearly all wells, statistical results for iron are not presented in 

the results section. Additionally, because of large variability of 

aluminum concentrations in water from MWQ 8, no results are 

presented for this constituent for this well.
38 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Table S-1. Data-quality objectives for water-quality analysis, Melrose Air Force Range.

[RPD, relative percent difference; <, less than; RL, reporting limit; NA, not applicable]

Constituent

Replicates

Fieldequipment 

blanks

Matrix spikes Matrix-spike 

replicates Trip blanks

Laboratorycontrol 

samples

Method 

blanks

RPD Reporting 

limit

Recovery 

limit RPD Concentration Recovery limit

Reporting 

limit

Physical and chemical properties:

Solids, residue 20 <10 86 - 106 20 NA 86 - 106 <10

Alkalinity 10 <5.0 95 - 110 10 NA 95 - 110 <5.0

Cyanide 20 <0.010 89 - 109 20 NA 89 - 109 <0.010

Sulfide 20 <4.0 70 - 130 20 NA 70 - 130 <4.0

Major ions:

Calcium 20 <0.20 90 - 110 20 NA 90 - 110 <0.20

Magnesium 20 <0.20 92 - 112 20 NA 92 - 112 <0.20

Sodium 20 <5.0 92 - 113 20 NA 92 - 113 <5.0

Potassium 20 <3.0 88 - 111 20 NA 88 - 111 <3.0

Sulfate 10 <5.0 90 - 110 10 NA 90 - 110 <5.0

Chloride 10 <3.0 90 - 110 10 NA 90 - 110 <3.0

Fluoride 10 <1.0 90 - 110 10 NA 90 - 110 <1.0

Bromide 10 <0.20 90 - 110 10 NA 90 - 110 <0.20

Nutrients and organic carbon:

Ammonia 10 <0.10 90 - 110 10 NA 90 - 110 <0.10

Nitrate-nitrite 10 <0.10 90 - 110 10 NA 90 - 110 <0.10

Orthophosphate 10 <0.50 90 - 110 10 90 - 110 <0.50

Phosphorus 20 <0.050 85 - 113 20 NA 85 - 113 <0.050

Organic carbon 10 <1.0 90 - 110 10 NA 90 - 110 <1.0

Trace elements:

Aluminum 20 <100 88 - 109 20 NA 88 - 109 <100

Antimony 20 <10 89 - 109 20 NA 89 - 109 <10

Arsenic 20 <15 90 - 110 20 NA 90 - 110 <15

Barium 20 <10 94 - 114 20 NA 94 - 114 <10

Beryllium 20 <5.0 89 - 112 20 NA 89 - 112 <5.0

Cadmium 20 <5.0 90 - 112 20 NA 90 - 112 <5.0

Chromium 20 <10 90 - 113 20 NA 90 - 113 <10

Cobalt 20 <10 88 - 108 20 NA 88 - 108 <10

Copper 20 <10 89 - 112 20 NA 89 - 112 <10

Iron 20 <100 91 - 112 20 NA 91 - 112 <100

Lead 20 <3.0 91 - 112 20 NA 91 - 112 <3.0
Supplemental Information 39

Table S-1. Data-quality objectives for water-quality analysis, Melrose Air Force Range.—Continued

Constituent

Replicates

Fieldequipment 

blanks

Matrix spikes Matrix-spike 

replicates Trip blanks

Laboratorycontrol 

samples

Method 

blanks

RPD Reporting 

limit

Recovery 

limit RPD Concentration Recovery limit

Reporting 

limit

Trace elements—Continued:

Manganese 20 <10 90 - 113 20 NA 90 - 113 <10

Mercury 10 <0.20 84 - 114 10 NA 84 - 114 <0.20

Molybdenum 20 <20 87 - 112 20 NA 87 - 112 <20

Nickel 20 <40 92 - 112 20 NA 92 - 112 <40

Selenium 20 <15 87 - 109 20 NA 87 - 109 <15

Silver 20 <10 87 - 111 20 NA 87 - 111 <10

Thallium 20 <10 89 - 109 20 NA 89 - 109 <10

Vanadium 20 <10 90 - 114 20 NA 90 - 114 <10

Zinc 20 <20 86 - 111 20 NA 86 - 111 <20

Organics:

Pesticides 40 <RL’s 55 - 147 40 NA 55 - 147 <RL’s

Explosives 40 <RL’s 42 - 145 40 NA 42 - 145 <RL’s

Volatile organic 

compounds

20 <RL’s 64 - 134 20 <RL 64 - 134 <RL’s

Semivolatile organic 

compounds

40 <RL’s 36 - 114 40 NA 36 - 114 <RL’s

Total organic halogens 30 <10 75 - 113 30 NA 75 - 113 <10

Perchlorate 20 <1.0 80 - 120 20 NA 80 - 120 <1.0
40 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Table S-2. Quality-control results for water-quality sampling at Melrose Air Force Range.

[RPD, relative percent difference; mg/L milligrams per liter; NA, not applicable; μg/L, micrograms per liter; <, less than. All quality-control medians are based on 

four individual concentrations]

Constituent Unit

Replicates

Fieldequipment 

blanks

Matrix spikes Matrix-spike 

replicates Trip blanks

Laboratorycontrol 

samples

Method 

blanks

Median RPD

Median 

concentration

Median 

percent 

recovery

Median RPD

Median 

concentration

Median 

percent 

recovery

Median 

concentration

Physical and chemical properties:

Solids, residue mg/L 2 7 NA NA NA 95 5

Alkalinity mg/L 0 9 NA NA NA 100 <2

Cyanide mg/L 9 0.004 93 3 NA 98 <0.002

Sulfide mg/L 0 <0.97 76 10 NA 82 <0.97

Major ions:

Calcium mg/L 3 0.63 102 4 NA 100 <0.03

Magnesium mg/L 0 0.12 101 4 NA 102 <0.02

Sodium mg/L 0 <1.5 103 3 NA 102 <1.5

Potassium mg/L 2 <0.49 103 4 NA 101 <0.49

Sulfate mg/L 0 0.36 108 1 NA 95 <0.20

Chloride mg/L 0 0.93 102 0 NA 94 <0.10

Fluoride mg/L 0 <0.03 97 2 NA 94 <0.03

Bromide mg/L 6 <0.03 96 2 NA 96 <0.03

Nutrients and carbon:

Ammonia mg/L 3 0.03 92 2 NA 100 <0.02

Nitrate-nitrite mg/L 3 <0.01 94 2 NA 104 <0.01

Orthophosphate mg/L 0 <0.04 98 3 NA 93 <0.04

Phosphorus mg/L 72 0.02 102 6 NA 99 0.02

Organic carbon mg/L 11 0.6 102 1 NA 102 <0.3

Trace elements:

Aluminum μg/L 5 52 98 3 NA 100 20

Antimony μg/L 0 <4 104 4 NA 103 <4

Arsenic μg/L 27 <4 100 4 NA 101 <4

Barium μg/L 3 2 104 4 NA 104 <2

Beryllium μg/L 0 <1 98 5 NA 102 <1

Cadmium μg/L 0 <1 102 4 NA 103 <1

Chromium μg/L 30 <1 102 4 NA 104 <1
Supplemental Information 41

Table S-2. Quality-control results for water-quality sampling at Melrose Air Force Range.—Continued

Constituent Unit

Replicates

Fieldequipment 

blanks

Matrix spikes Matrix-spike 

replicates Trip blanks

Laboratorycontrol 

samples

Method 

blanks

Median RPD

Median 

concentration

Median 

percent 

recovery

Median RPD

Median 

concentration

Median 

percent 

recovery

Median 

concentration

Trace elements—Continued:

Cobalt μg/L 0 <1 99 4 NA 100 <1

Copper μg/L 0 4 103 4 NA 102 <1

Iron μg/L 14 96 100 3 NA 101 <13

Lead μg/L 0 <2 103 3 NA 104 <2

Manganese μg/L 12 6 101 4 NA 103 <1

Molybdenum μg/L 10 <2 104 4 NA 102 <2

Nickel μg/L 0 <2 102 5 NA 104 <2

Selenium μg/L 27 <5 99 3 NA 98 <5

Silver μg/L 0 <1 106 4 NA 104 <1

Thallium μg/L 0 <7 101 3 NA 100 <7

Vanadium μg/L 3 <2 101 4 NA 103 <2

Zinc μg/L 17 20 97 5 NA 98 <7

Organics:

Pesticides μg/L 6

(Dieldrin)

<MDL’s 80 3 NA 85 0.016

(Dieldrin)

Explosives μg/L NA <MDL’s 101 5 NA 98 <MDL’s

Volatile organic 

compounds

μg/L NA <MDL’s 104 1 0.31

(methylene 

chloride)

104 <MDL’s

Semivolatile 

organic compounds

μg/L NA <MDL’s 67 15 NA 67 <MDL’s

Total organic 

halogens

μg/L NA <10 91 0 NA 90 <10

Perchlorate μg/L NA <3.0 98 5 NA 94 <3.0
42 Ground-Water Hydrology and Water Quality of the Southern High Plains Aquifer, Melrose Air Force Range, New Mexico

Table S-3. Turbidity values and outlier data points for ground-water samples collected at Melrose Air Force Range.

[NTU’s, nephlometric turbidity units; std. dev., standard deviation]

Turbidity (NTU’s) Outliers

Constituent Sample period

Median Std. dev. Well

NA NA MWQ 2 Aluminum

Chromium

Cobalt

Copper

Iron

Vanadium

June, August

August

March

August

August

August

0.5 0.2 MWQ 3 Nickel August

0.6 0.4 MWQ 4 Nickel August

0.7 0.2 MWQ 5 Lead

Zinc

March

March

1.5 1.3 MWQ 6 Iron June, December

0.8 0.3 MWQ 7 Nickel August

165.5 96.5 MWQ 8 Aluminum

Barium

Iron

Lead

Manganese

Zinc

June, August, December

June

June, August, December

June

June

June

28.5 12.5 MWQ 9 Aluminum

Iron

Nickel

August

December

August

0.7 0.4 MWQ 10 Zinc August

1.0 1.7 MWQ 11 Nickel August

12.3 3.6 MWQ 12 Iron

Nickel

December

August

29.6 15.3 MWQ 13 Iron

Nickel

June

August

16.5 57.9 MWQ 14 Aluminum

Iron

December

December

8.3 9.7 MWQ 15 Iron

Nickel

December

August

5.5 6.5 MWQ 16 Iron

Lead

June

March

36.4 22.0 MWQ 17 Aluminum

Dissolved solids

Iron

Dissolved solids

August

June 

August, March

June