science 

uses

for a changing world - 

Prepared in cooperation with the

NORTH PLATTE NATURAL RESOURCES DISTRICT

Selected Field and Analytical Methods and 

Analytical Results in the Dutch Flats Area, 

Western Nebraska, 1995-99

Open-File Report 00-413

U.S. Department of the Interior 

U.S. Geological Survey

U.S. Department of the Interior 

U.S. Geological Survey

Selected Field and Analytical Methods and 

Analytical Results in the Dutch Flats Area, 

Western Nebraska, 1995-99

By I.M. Verstraeten, G.V. Steele, J.K. Bohlke, T.E. Kraemer, J.C. Cannia, 

D.E. Hitch, K.E. Wilson, and A.E. Games

Open-File Report 00-413

Prepared in cooperation with the

NORTH PLATTE NATURAL RESOURCES DISTRICT
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the 

U.S. Geological Survey.

Lincoln, Nebraska: 2001

For additional information write to:

District Chief 

U.S. Geological Survey 

406 Federal Building 

100 Centennial Mall North 

Lincoln, NE 68508

Copies of this report can be purchased from:

U.S. Geological Survey 

Information Services 

Box 25286 

Denver, CO 80225-0286
CONTENTS

Abstract.......................................................................................................................................................^ 1

Introduction ...............................................................................................................................................................^ 1

Field and Analytical Methods................................................................................................................................................ 3

Site Selection and Identification ................................................................................................................................. 3

Surface-Water Sites ........................................................................................................................................... 3

Ground-Water Sites ........................................................................................................................................... 4

Nested-Well Construction ........................................................................................................................................... 13

Sample-Collection Procedures ................................................................................................................................... 15

Analytical Methods ..................................................................................................................................................... 15

Major Ions and Nitrogen Species ...................................................................................................................... 15

Dissolved Gases................................................................................................................................................. 16

Chlorofluorocarbons.......................................................................................................................................... 16

Tritium, Helium, and Neon Isotopes ................................................................................................................. 17

Hydrogen and Oxygen Isotopes in Water.......................................................................................................... 17

Nitrogen Isotopes in Nitrate and Dissolved Nitrogen Gas................................................................................ 17

Uranium and Uranium Activity Ratios.............................................................................................................. 18

Calculation of Recharge Temperatures, Excess Air, and Excess Nitrogen in Ground Water............................ 18

Quality Assurance and Quality Control ...................................................................................................................... 19

Analytical Results ................................................................................................................................................................. 19

References ...............................................................................................................................................................^ 52

FIGURES

1. Map show ing location of the Dutch Flats area and surface-water sampling sites, western Nebraska.................... 2

2. Map showing location of ground-water sampling sites, Dutch Flats area, western Nebraska................................ 4

3. Diagram showing township-range-section numbering system ............................................................................... 14

TABLES

1. Surface-water sampling sites, Dutch Flats area, western Nebraska........................................................................ 3

2. Well information for ground-water-quality monitoring network, Dutch Flats area, western Nebraska ................ 5

3. Selected water-quality constituents, reporting levels, analytical methods, references for analytical methods,

and regulatory levels used for the study, Dutch Flats area, western Nebraska,...................................................... 16

4. Water temperature, dissolved oxygen, and dissolved-gas concentrations, and calculated recharge 

temperature, excess air, and excess nitrogen in surface- and ground-water samples from selected sites, 

Dutch Flats area, western Nebraska, 1998 through 1999 ....................................................................................... 20

5. Nitrogen, hydrogen, oxygen, and helium isotopes in surface- and ground-water samples from selected sites,

Dutch Flats area, western Nebraska, 1998 through 1999 ....................................................................................... 23

6. Chlorofluorocarbons in surface- and ground-water samples from selected sites, Dutch Flats area,

western Nebraska, 1998.......................................................................................................................................... 29

7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch

Flats area, western Nebraska, 1995 through 1999 ................................................................................................. 30

Content- iii
CONVERSION FACTORS, ABBREVIATIONS, AND VERTICAL DATUM

Multiply

inch (in.)

inch (in.)

foot (ft)

meter (m)

mile (mi)

gram (g)

gallon (gal)

liter (L)

milliliter (mL)

picocuries per liter (pCi/L)

By

Length

2.54

25.4

0.3048

3.281

1.609

Weight

0.03527

Volume

3.785

0.2642

0.0338

Radioactivity

0.037

To obtain

centimeter

millimeter

meter

foot

kilometer

ounce

liter

gallon

ounce, fluid

becquerels per liter

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

°F=(1.8x°C) + 32. 

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

°C = (°

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

of 1929) a geodetic datum derived from a general adjustment of the first-order level nets of both 

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

Altitude, as used in this report, refers to distance above or below sea level.

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

(mS/cm at 25 °C).

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

micrograms per liter (mg/L), or picocuries per kilogram (pg/kg).

iv Selected Field and Analytical Methods and Analytical Results in the Dutch Flats Area, Western Nebraska, 1995-9^
Selected Field and Analytical Methods and Analytical 

Results in the Dutch Flats Area, Western Nebraska, 

1995-99

By I.M. VERSTRAETEN1 , G.V. STEELE1 , J.C. CANNIA2, J.K. BOHLKE3, I.E. KRAEMER3 

D.E. HITCH4 , K.E. WILSON1 , and A.E. CARNES1

Abstract

A study of the water resources of the Dutch 

Flats area in the western part of the North Platte 

Natural Resources District, western Nebraska, 

was conducted from 1995 through 1999 to 

describe the surface water and hydrogeology, the 

spatial distribution of selected water-quality constituents in surface and ground water, and the 

surface-water/ground-water interaction in 

selected areas. This report describes the selected 

field and analytical methods used in the study and 

selected analytical results from the study not previously published. Specifically, dissolved gases, 

age-dating data, and other isotopes collected as 

part of an intensive sampling effort in August and 

November 1998 and all uranium and uranium isotope data collected through the course of this 

study are included in the report.

INTRODUCTION

Human activities, such as agriculture, commonly 

affect the distribution, interaction, and quality of surface and ground water. It has been demonstrated that 

contaminated aquifers discharging to streams can 

degrade surface-water quality and that streams discharging to ground water can degrade ground-water

^.S. Geological Survey, Lincoln, Nebraska.

2North Platte Natural Resources District, Gering, Nebraska.

3U.S. Geological Survey, Reston, Virginia.

4 U.S. Geological Survey, North Platte, Nebraska.

quality, especially when induced infiltration occurs 

(Verstraeten and others, 1999). A study of the water 

resources of the Dutch Flats area in the western part of 

the North Platte Natural Resources District (NRD), 

western Nebraska, was conducted from 1995 through 

1999 to describe the surface water and hydrogeology, 

the spatial distribution of selected water-quality 

constituents in surface and ground water, and the 

surface-water/ground-water interaction in selected 

areas.

The Dutch Flats area, a part of Scotts Bluff and 

Sioux Counties, in the western part of the North Platte 

NRD (fig. 1), encompasses the majority of the study 

area and locally is the prominent terrain feature. It also 

includes an area north of the Interstate Canal and south 

of the Platte River. Previous studies (Conservation and 

Survey Division, 1980a, b; Verstraeten and others, 

1995; Steele and Cannia, 1997; Druliner and others, 

1999) suggested that large amounts of nitrate are 

present in ground water from the alluvial sediment in 

the Dutch Flats area but are not present in surface 

water. These studies also suggested that at selected 

locations in the Dutch Flats area, large concentrations 

of radon, uranium, and gross alpha as natural uranium 

are present. Concentrations in excess of existing or 

proposed U.S. Environmental Protection Agency 

(2000) Maximum Contaminant Levels (MCLs) for 

nitrate, radon, and uranium were found in surface or 

ground water.

To evaluate the water resources in the Dutch Flats 

area, more information was needed about the quantity 

and quality of surface and ground water and their 

interactions. To evaluate the interaction of surface and 

ground water, a study was conducted from 1995 

through 1999 by the U.S. Geological Survey (USGS),

Introduction
42"081 42"

R. 58 W.

Base from U.S. Geological Survery digital data 

1:100,000 digital data, 1972, 

Universal Transverse Mercator projection. Zone 13 

central meridian -105°00'

5 KILOMETERS

EXPLANATION

SW5 A Surface-water sampling site (table 1) and map index number 

Figure 1. Location of the Dutch Flats area and surface-water sampling sites, western Nebraska.

2 Selected Field and Analytical Methods and Analytical Results in the Dutch Flats Area, Western Nebraska, 1995-99
in cooperation with the North Platte NRD, to define 

the surface-water/ground-water interaction and the 

potential effect of seepage from irrigation canals on 

water quantity and quality in the Dutch Flats area 

(fig. 1) in the western part of the North Platte NRD. 

The specific objectives of the study were:

 To describe surface water and hydrogeology,

 To describe spatial distribution of selected waterquality constituents in surface and ground water,

 To describe surface-water/ground-water interaction 

in selected areas, and

 To estimate ground-water, nitrogen, and uranium 

fluxes.

The purpose of this report is to describe the 

selected field and analytical methods used in the study 

and the analytical results of the study not published in 

the USGS Water-Data Reports for 1997, 1998, and 

2000 (Boohar and Walczyk, 1997, p. 254-273, 1998, 

p. 303-395; Boohar, 2000, p. 342-417). The previously published analytical results can be retrieved 

from the USGS National Water Information system on 

the World Wide Web at URL: 

http://water.usgs. gov/ne/nwis/n wis

FIELD AND ANALYTICAL METHODS

Surface-water and ground-water site selection and 

identification are described in this report, in addition 

to ground-water monitoring-well construction 

methods. The sample collection and laboratory procedures also are described, as well as the qualityassurance and quality-control measures used during 

the study. Most of the geologic nomenclature used in 

this report is that used by the USGS. However, the 

term "Lance aquifer" is used by the University of 

Nebraska-Lincoln Conservation and Survey Division.

Site Selection and Identification

Surface-Water Sites

Eleven surface-water sites representing the major 

hydrologic features in the Dutch Flats area were 

selected for this study (fig. 1, table 1). One spring, 

Akers Draw, also was included to evaluate groundwater seepage from the upland terrace. Water in the 

Interstate Canal is withdrawn from the North Platte 

River about 50 mi upstream in Wyoming. Site 

accessibility was a major consideration in the siteselection process.

For identification of surface-water sampling sites, 

the first identifier is the USGS official station name 

(table 1). The second identifier, generally an eightTable 1 . Surface-water sampling sites, Dutch Flats area, western Nebraska

[USGS, U.S. Geological Survey; ft, feet]

Map 

index 

number 

(fig-1)

SW1

SW2

SW3

SW4

SW5

SW6

SW7

SW8

SW9

SW10

SW11

USGS site name

Interstate Canal 6 miles northwest of Morrill, Nebr.

North Platte River at Wyoming-Nebraska State line

Tri-State Canal 2 miles west of Morrill, Nebr.

Horse Creek 0.5 mile downstream from 

Wyoming-Nebraska State line

Owl Creek near Lyman, Nebr. 1

Horse Creek near Lyman, Nebr.

Dry Sheep Creek near Morrill, Nebr.

Sheep Creek north of Tri-State Canal, 

near Morrill, Nebr.

North Platte River at Morrill, Nebr.

Akers Draw near Morrill, Nebr.

Wetlands 0.75 mile north of Morrill, Nebr.

USGS identification 

number

06656630

06674500

06675100

06677120 

06677300

06677500

06677985

06677995

06678500

06678610

415830103551701

Latitude and 

longitude 

(degrees, minutes, 

seconds)

420326 1035706

415925 1040257

415808 1035804

415512 1040240 

415548 1040017

415621 1035913

420058 1035823

415814 1035714

415612 1035544

415833 1035329

4158301035517

Landsurface 

altitude 

(ft above 

sea level)

4,206

4,020

4,013

4,040 

4,020

3,992

4,060

4,008

3,978

4,010

3,980

lrThis station is on that part of the stream previously called Kiowa Creek by the USGS.

Field and Analytical Methods
digit surface-water USGS identification number, is 

assigned in a downstream direction along the main 

stream. The first two digits "06" represent the major 

river basin, which is the Missouri River Basin. However, because the wetlands site is not a flowing stream, 

the wetlands site (SW11) was identified in a fashion 

similar to a ground-water site as described later in this 

section.

Ground-Water Sites

Multiple wells at a site are referred to as "nested 

wells" in this report; a single well at a site or one of the 

wells at a nested well site is referred to as a "well." 

Sites were selected to produce parallel transects of 

semilinear lines running from the Interstate Canal to 

about 2 to 3 mi south of the North Platte River (fig. 2, 

table 2). Each transect was placed in a location that, as 

much as possible, allowed easy access during inclement weather.

EXPLANATION

6I» Ground-water sampling (table 2) and 

test-hole site and map index number

R. 58 W.

Base from U.S. Geological Survery digital data, 

1:100,000 digital data, 1972, 

Universal Transverse Mercator projection. Zone 13 

central meridian -1D5°00'

Figure 2. Location of ground-water sampling sites, Dutch Flats area, western Nebraska.

4 Selected Field and Analytical Methods and Analytical Results in the Dutch Flats Area, Western Nebraska, 1995-99
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Field and Analytical Methods
Table 2. Well information for ground-water-quality monitoring network, Dutch Flats area, western Nebraska Continued

Selected Fielda

a

3

fo'

SL

2.

3 

o

a

3

 <

o'

SL

3)

c.

5'

3

(D

O

0

TJ

§

1

1

W

(D^

(DO1

W

»

8

Map 

index 

number 

(fig- 2)

11-1

11-2

11-3

U-l

1J-2

1J-3

IK-1

IK-2

IK-3

1L-1

1L-2

1L-3

1M-1

1M-2

1M-3

1N-1

2A-1

2B-1

2B-2

2B-3

2C-1

2C-2

2C-3

U.S. Geological 

Survey station 

identification 

number

415811103555801

415811103555802

415811103555803

415738103554701

415738103554702

415738103554703

415738103551601

415738103551602

415738103551603

415628103554901

415628103554902

415628103554903

420121103560501

420121103560502

420121103560503

420244103561401

420316103563201

420313103563101

420313103563102

420313103563103

420234103564001

420234103564002

420234103564003

Legal description

23N57W16AAAC1

23N 57W 16 AAAC2

23N57W16AAAC3

23N57W15CBCB1

23N 57W 15 CBCB2

23N 57W 15 CBCB3

23N57W22ABAB1

23N 57W 22 ABAB2

23N 57W 22 ABAB3

23N57W28AAAA1

23N 57W 28 AAAA2

23N 57W 28 AAAA3

24N 57W 28 DABA1

24N 57W 28 DABA2

24N 57W 28 DABA3

24N 57W 16 DCDD1

24N57W16BDAA1

24N 57W 16 BDAD1

24N57W16BDAD2

24N 57W 16 BDAD3

24N57W16CDDA1

24N 57W 16 CDDA2

24N 57W 16 CDDA3

Well 

registration 

number1

G-088536

G-088536

G-088536

G-088535

G-088535

G-088535

G-091664

G-091664

G-091664

G-088537

G-088537

G-088537

G-091668

G-091668

G-091668

G-091666

G-085448

G-085450

G-085450

G-085450

G-085447

G-085447

G-085447

Hydrogeologic 

condition

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

Aquifer 

type

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Well 

type

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

Latitude and 

longitude

415811 1035558

415811 1035558

415811 1035558

415738 1035547

415738 1035547

415738 1035547

415738 1035516

415738 1035516

4157381035516

415628 1035549

415628 1035549

415628 1035549

420121 1035605

420121 1035605

420121 1035605

420244 1035614

4203161035632

420313 1035631

420313 1035631

420313 1035631

420234 1035640

420234 1035640

420234 1035640

Landsurface 

altitude 

(ft above 

sea level)

3,991

3,991

3,991

3,992

3,992

3,992

3,984

3,984

3,984

3,980

3,980

3,980

4,110

4,110

4,110

4,185

4,211

4,202

4,202

4,202

4,188

4,188

4,188

Land

surfa

altitu

(m abo

sea le

1,216

1,216

1,216

1,217

1,217

1,217

1,214

1,214

1,214

1,213

1,213

1,213

1,253

1,253

1,253

1,276

1,284

1,281

1,281

1,281

1,276

1,276

1,276
Table 2. Well information for ground-water-quality monitoring network, Dutch Flats area, western Nebraska Continued

Field andfi

SL

I

3

Map 

index 

number

(fig. 2)

2D-1

2D-2

2D-3

ZB-l

2F-1

2F-2

2F-3

2G-1

2H-2

2J-1

2J-2

2J-3

2L-1

2L-2

2L-3

2T-1

3B-1 

3B-2

3C-1

3C-2

3C-3

U.S. Geological 

Survey station 

identification 

number

420148103563101

420148103563102

420148103563103

420516103562501

420005103562801

420005103562802

420005103562803

415854103561101

415823103561602

415721103561501

415721103561502

415721103561503

415628103562401

415628103562402

415628103562403

415547103561704

420325103570901 

420325103570902

420243103570701

420243103570702

420243103570703

Legal description

24N 57W 21 CDDD1

24N 57 W 21 CDDD2

24N 57W 21 CDDD3

25N 57W 35 DCDDl

24N 57W 33 DCCC1

24N 57W 33 DCCC2

24N 57W 33 DCCC3

23N57W 9ACAA1

23N57W 9DCC2

23N 57W 21 ABBAl

23N 57W 21 ABBA2

23N 57W 21 ABBA3

23N 57W 28 BAAAl

23N 57W 28 BAAA2

23N 57W 28 BAAA3

23N 57W 28 DCCC1

24N 57W 17 AAAD1 

24N 57W 17 AAAD2

24N57W16CCCB1

24N57W16CCCB2

24N57W16CCCB3

Well 

registration 

number1

G-088540

G-088540

G-088540

G-091670

G-088544

G-088544

G-088544

G-088532

G-088534

G-091364

G-091364

G-091364

G-088538

G-088538

G-088538

G-101646

G-085451 

G-085451

G-088539

G-088539

G-088539

Hydrogeologic 

condition

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

CF

UCF 

UCF

UCF

UCF

UCF

Aquifer 

type

Q

Q

Q

BR

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

CD

BR 

Q

Q

Q

Q

Well 

type

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM 

RM

RM

RM

RM

Latitude and 

longitude

420148 1035631

420148 1035631

420148 1035631

420516 1035625

420005 1035628

420005 1035628

420005 1035628

4158541035611

415823 1035616

415721 1035615

415721 1035615

415721 1035615

415628 1035624

415628 1035624

415628 1035624

415547 1035617

420325 1035709 

420325 1035709

420243 1035707

420243 1035707

420243 1035707

Landsurface 

altitude 

(ft above 

sea level)

4,137

4,137

4,137

4,248

4,100

4,100

4,100

4,075

4,010

3,990

3,990

3,990

3,982

3,982

3,982

3,986

4,200 

4,200

4,181

4,181

4,181

Land

surfa

altitu

(m abo

sea lev

1,261

1,261

1,261

1,295

1,250

1,250

1,250

1,242

1,222

1,216

1,216

1,216

1,214

1,214

1,214

1,215

1,280 

1,280

1,274

1,274

1,274
Table 2. Well information for ground-water-quality monitoring network, Dutch Flats area, western Nebraska Continued

Selected Field a

Q.

nj_

I

a3=

o

Q. W

D>

3 

Q.

SL

o' 

SL

3J

i?

5'

(D

O

1

m

D>

w

JD>

1

1

(D

3

10

.»

1

Map 

index 

number 

(fig. 2)

3E-1

3E-2

3E-3

3F-1

3F-2

3F-3

4A-1

4B-1

4B-2

4B-3

5A-1

5B-1

5B-2

5B-3

5C-1

5C-2

5D

5E-1

5E-2

5F

6A

6B

U.S. Geological 

Survey station 

identification 

number

420056103570301

420056103570302

420056103570303

420005103570301

420005103570302

420005103570303

420333103574001

420307103574001

420307103574002

420307103574003

420128103514801

420053103512701

420053103512702

420053103512703

420002103511101

420002103511102

415829103511001

415643103505201

415643103505202

415553103504101

420757104024701

420628104021001

Legal description

24N 57W 28 CCCC1

24N 57W 28 CCCC2

24N 57W 28 CCCC3

24N 57W 32 DDDD1

24N 57W 32 DDDD2

24N 57W 32 DDDD3

24N57W 8DCCC1

24N57W17ACCC1

24N 57W 17 ACCC2

24N 57W 17 ACCC3

24N56W30ACAA1

24N 56W 31 ABAA1

24N56W31 ABAA2

24N56W31 ABAA3

23N56W 6AAAA1

23N56W 6AAAA2

23N56W 7DDDD1

23N56W20CCAA1

23N 56W 20 CCAA2

23N 56W 29 CDBD1

25N 58W 13 CDBC1

25N58W25DABB1

Well 

registration 

number1

G-091667

G-091667

G-091667

G-091366

G-091366

G-091366

G-091665

G-091365

G-091365

G-091365

G-099874

G-091669

G-091669

G-091669

G-092640

G-092640

G-092641

G-092643

G-092643

G-093234

G-093083

G-094662

Hydrogeologic 

condition

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

CF

Aquifer 

type

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

BR

Q

Q

Q

BR

BR

Well 

type

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

Latitude and 

longitude

420056 1035703

420056 1035703

420056 1035703

420005 1035703

420005 1035703

420005 1035703

420333 1035740

4203071 035740

4203071 035740

4203071 035740

420129 1035148

420053 1035127

420053 1035127

420053 1035127

4200021035111

420002 1035111

415829 1035110

415643 1035052

415643 1035052

415553 1035041

420757 1040247

420628 1040210

Landsurface 

altitude 

(ft above 

sea level)

4,110

4,110

4,110

4,100

4,100

4,100

4,210

4,192

4,192

4,192

4,228

4,158

4,158

4,158

4,098

4,098

4,050

3,960

3,960

3,949

4,206

4,170

Lan

surfa

altitu

(m abo

sea le

1,253

1,253

1,253

1,250

1,250

1,250

1,283

1,278

1,278

1,278

1,289

1,267

1,267

1,267

1,249

1,249

1,234

1,207

1,207

1,204

1,282

1,271
Table 2. Well information for ground-water-quality monitoring network, Dutch Flats area, western Nebraska Continued

Field andAnalyt

o' 

SL

13- 

o 

a 

«»

Map 

index 

number 

(fig. 2)

6C

6D-1

6D-2

6E

6F

6G-1

6G-2

6M-1

6M-2

6H-1

6H-2

61

7A-1

7A-2

7B

7C-1

7C-2

7D-1

7D-2

7E-1

7E-2

U.S. Geological 

Survey station 

identification 

number

420514104015101

420338104014401

420338104014402

420145104025001

420003104023801

415739104021101

415739104021102

415525104023801

415525104023802

415852104024801

415852104024802

415402104015501

420657104010301

420657104010302

420524104003901

420334104003201 

420334104003202

420153104002401

420153104002402

420006104004401

420006104004402

Legal description

25N 57W 31 CCCC1

24N58W 10DDDD1

24N58W 10DDDD2

24N 58W 27 BBBC1

23N58W 3BBAC1

23N 58W 15 CDAD1

23N 58W 15 CDAD2

23N58W34BCCB1

23N 58W 34 BCCB2

23N58W 9 ADDA 1

23N58W 9ADDA2

22N 58W 3 DCCD1

25N 57W 19 DCDD1

25N 57 W 19 DCDD2

25N57W32CCBB1

24N58W 13BBBB1 

24N 58W 13 BBBB2

24N58W24CCCC1

24N 58W 24 CCCC2

23N58W 2AABB1

23N58W 2AABB2

Well 

registration 

number1

G-094661

G-094659

G-094659

G-093242

G-094681

G-092647

G-092647

G-092648

G-092648

G-094679

G-094679

G-092638

G-093082

G-093082

G-093081

G-094660 

G-094660

G-093241

G-093241

G-094678

G-094678

Hydrogeologic 

condition

UCF

UCF

UCF

UCF

UCF

UCF

CF

UCF

UCF

UCF

UCF

UCF

UCF

CF

UCF

UCF 

UCF

UCF

UCF

UCF

UCF

Aquifer 

type

BR

Q

Q

Q

BR

Q

Q

Q

Q

Q

Q

LC

BR

BR

BR

Q 

Q

Q

Q

BR

Q

Well 

type

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM 

RM

RM

RM

RM

RM

Latitude and 

longitude

420514 1040151

420338 1040144

420338 1040144

420145 1040250

420003 1040238

4157391040211

4157391040211

415525 1040238

415525 1040238

415852 1040248

415852 1040248

415402 1040155

420657 1040103

420657 1040103

420524 1040039

420334 1040032 

420334 1040032

420153 1040024

420153 1040024

420006 1040044

420006 1040044

Landsurface 

altitude 

(ft above 

sea level)

4,163

4,125

4,125

4,153

4,070

4,021

4,021

4,053

4,053

4,027

4,027

4,054

4,192

4,192

4,175

4,173 

4,173

4,135

4,135

4,124

4,124

Lan

surfa

altitu

(m ab

sea le

1,269

1,257

1,257

1,26

1,24

1,22

1,22

1,23

1,23

1,22

1,22

1,23

1,27

1,27

1,27

1,27

1,27

1,26

1,26

1,25

1,25
g Table 2. Well information for ground-water-quality monitoring network, Dutch Flats area, western Nebraska Continued

Selected Fielda

Q.

3

5L

I

0

I

v>

u

Q.

3

5L

1

3D

0

w

E

5f

5"

0

D

o

 n 

u

|

1

1

z

w

i

1

Map 

index 

number 

(fig- 2)

7F-1

7F-2

7G-1

7G-2

7H

8A-1

8A-2

8B

8C

8D-1

8D-2

8E

8F-1

8F-2

8G

9B

9C

9D-1

9D-2

9E-1

U.S. Geological 

Survey station 

identification 

number

415730104002301

415730104002302

415837104000601

415837104000602

415544104003701

420333103583401

420333103583402

420148103583101

420004103581401

415814103581201

415814103581202

415719103583601

415640103591201

415640103591202

415545103575801

415944103532901

415840103533101

415722103532401

415722103532402

415546103532201

Legal description

23N58W 13 CCCCI

23N 58W 13 CCCC2

23N58W12CDCB1

23N 58W 12 CDCB2

23N 58W 35 AABA1

24N57W 18AAAA1

24N 57W 18 AAAA2

24N57W30AABB1

23N57W 6AAAA1

23N57W 7DDDD1

23N57W 7DDDD2

23N57W19ABBA1

23N 57W 19 CCCCI

23N 57W 19 CCCC2

23N57W32BBBB1

23N57W 1ACBC1

23N57W 11DAAA1

23N5T>; 24BBBB1

23N 57W 24 BBBB2

23N57W36BBBB1

Well 

registration 

number1

G-092646

G-092646

G-093238

G-093238

G-093239

G-094658

G-094658

G-093240

G-093235

G-093087

G-093087

G-093089

G-094677

G-094677

G-093237

G-093086

G-093088

G 093090

G-093090

G-094680

Hydrogeologic 

condition

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

Aquifer 

type

Q

Q

BR2

Q

Q

Q

Q

Q

BR

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

CD

Well 

type

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

Latitude and 

longitude

415730 1040023

415730 1040023

415837 1040006

415837 1040006

415544 1040037

420333 1035834

420333 1035834

420148 1035831

420004 1035814

4158141035812

415814 1035812

415719 1035836

415640 1035912

415640 1035912

415545 1035758

415944 1035329

415840 1035331

415722 1035324

415722 1035324

415546 1035322

Landsurface 

altitude 

(ft above 

sea level)

4,011

4,011

4,092

4,092

4,025

4,165

4,165

4,100

4,082

4,016

4,016

4,003

4,000

4,000

4,002

4,079

4,030

3,965

3,965

3,978

Lan

surf

altitu

(m ab

sea le

1,22

1,22

1,24

1,24

1,22

1,26

1,26

1,25

1,24

1,22

1,22

1,22

1,21

1,21

1,22

1,24

1,22

1,20

1,20

1,21
Table 2. Well information for ground-water-quality monitoring network, Dutch Flats area, western Nebraska Continued

^1

Held andAnalytical A

/lethods

Map 

index 

number

(fig. 2)

9E-2

10A-1

10A-2

10C

10D-1

10D-2

10E-1

10E-2

10G-1

10G-2

10K-1

10M-1

10M-2

ION-1

ION-2

IK-94-1 

(Kiowa 

1-D 

IK-94-2 

(Kiowa 

1-2)

U.S. Geological 

Survey station 

identification 

number

415546103532202

420259103481601

420259103481602

420003103410301

415742103482001

415742103482002

415525103484601

415525103484602

415607103484801

415607103484802

415817103492401

415625103480201

415625103480202

415910103493701

415910103493702

415547103561701 

415547103561702

Legal description

23N 57W 36 BBBB2

24N 56W 10 CDCA1

24N 56W 10 CDCA2

23N56W 4AABA1

23N56W16DADA1

23N56W16DADA2

23N56W34BCCB1

23N 56W 34 BCCB2

23N56W28DAAA1

23N 56W 28 DAAA2

23N56W16BAAA1

23N 56W 27 ABDC1

23N 56W 27 ABDC2

23N56W09BABA1

23N 56W 09 BABA2

23N 57W 28 DCCC1 

23N 57W 28 DCCC2

Well 

registration 

number1

G-094680

G-093089

G-093089

G-093084

G-092642

G-092642

G-092645

G-092645

G-093085

G-093085

G-101648A

G-092644

G-092644

G-101643A

G-101643B

G-082124B 

G-082124B

Hydrogeologic 

condition

CF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF

UCF 

UCF

Aquifer 

type

Q

BR

BR

BR

Q

Q

Q

Q

Q

Q

BR

Q

Q

Q

Q

CD 

Q

Well 

type

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM

RM 

RM

Latitude and 

longitude

415546 1035322

420259 1034816

420259 1034816

420003 1034903

415742 1034820

415742 1034820

415525 1034846

415525 1034846

415607 1034848

415607 1034848

415817 1034924

415625 1034802

415625 1034802

415910 1034937

415910 1034937

415547 1035617 

415547 1035617

Landsurface 

altitude 

(ft above 

sea level)

3,978

4,190

4,190

4,125

3,972

3,972

3,941

3,941

3,940

3,940

4,036

3,948

3,948

4,050

4,050

3,986 

3,986

Land

surfa

altitu

(m abo

sea le

1,212

1,277

1,277

1,257

1,211

1,211

1,201

1,201

1,201

1,201

1,230

1,203

1,203

1,234

1,234

1,215 

1,215
£ Table 2. Well information for ground-water-quality monitoring network, Dutch Flats area, western Nebraska Continued

#fl>

5

Q. 1 n 

5'

a

§

a

>

3

0)

£o'

8J.

I

o

&

0)

a

>

3

0)

*

I

31

ff

Map

index

number

(fig. 2)

26K-94-1

(Kiowa

26-1)

26K-94-2

(Kiowa

26-2)

C. Morrill

U.S. Geological

Survey station

identification

number Legal description

415535103554501 23N 57W 28 DDDD1

415535103554502 23N 57W 28 DDDD2

415816103513201 23N 56W 17 BBBA1

Well

registration

number1

G-082124C

G-082124C

G-093042

Hydrogeologic Aquifer

condition type

UCF Q

UCF Q

CF CD

Landsurface

altitude

Well Latitude and (ft above

type longitude sea level)

RM 4155501035547 3,981

RM 415550 1035547 3,981

RD 415816 1035132 4,050

Lan

surf

altit

(m ab

sea l

1,21

1,21

1,23

'Well registration numbers are assigned by the Nebraska Department of Natural Resources.

2 Brule sand.

ffl O1
Initially three transects were installed in a northsouth direction near the center of the study area. Sets 

of nested wells in a transect are about 1 mi apart. Two 

sites (2A and 2E) are upgradient of the Interstate 

Canal; all other sites are in or near areas with active 

surface-water irrigation and are downgradient from 

the Interstate Canal. Additional nested wells 

were installed at approximately 2-mi intervals in 

the study area.

Analysis of the chemical interaction between 

surface and ground water requires transects that are 

parallel to ground-water flow paths, hereinafter 

referred to as flow paths. Flow paths in the study area 

are variable. To determine vertical ground-water flow 

components, nested wells with screens completed at 

different depths were installed at locations having sufficient saturated thickness. Sufficient saturated 

thickness was determined by drilling a test hole. Sufficient saturated thickness was defined as areas containing saturated sand and gravel deposits of about 20 ft 

(feet) or more. In areas containing saturated deposits 

less than 20 ft thick, a single well was installed.

Four different methods of ground-water site identification were used in this report (table 2). The first 

method, well identification number/station name, is 

associated with the transect number for the wells. 

Each well in a transect was given a 3- or 4-character 

identification number, letter, number format. The 

first number assigned was based on the transect 

number in which the well was located first transect 

(1), second transect (2), and so forth. The letter 

sequence designated wells farthest north as A, then 

southward to B, C, and so forth, with some exceptions. 

Terminal numbers were assigned to monitoring wells 

in a nest and were based on relative well depth 

deepest, -1; medium or intermediate depth, -2 (or 

shallowest for a two-well nest); and shallowest, -3 (for 

a three-well nest). Locations containing a single monitoring well were assigned a single terminal number 

(such as 1F-1) or no terminal number (such as 5D).

The second method is the unique USGS station 

identification number, which is a 15-character number 

derived from the international system of latitude and 

longitude. This number contains no blanks or alphabetic characters and generally is used as a control 

number. Although the station identification number 

was derived initially from the site location, the number 

is a numeric identifier and has no locational significance (Mathey, 1990, p. 2-10). If two or more wells 

are located within the same second of latitude or longitude, they are distinguished by adding a sequential 

digit to the number. Sequential numbers are assigned 

by order of inventory.

The third method, the legal description (fig. 3, 

table 2), is based on the land subdivisions from the 

U.S. Bureau of Land Management's survey of 

Nebraska. The number preceding N (north) indicates 

the township or tier, the number preceding W (west) 

indicates the range, and the number preceding the terminal letters indicates the section in which the well is 

located. The last letters, designated A, B, C, and D, 

denote the quarter section, the quarter-quarter section, 

the quarter-quarter-quarter section, and the quarterquarter-quarter-quarter section. The designation is 

given in a counterclockwise direction beginning with 

"A" in the northeast corner of each subdivision. Like 

the USGS station identification number, if two or more 

wells are located within the same subdivision, they are 

distinguished by adding a sequential digit to the well 

number and are assigned by order of inventory. For 

example, 24N 57W 15 CBBD1 (fig. 3) would be in 

township 24 north, range 57 west, section 15, quarter 

section C, quarter-quarter section B, quarter-quarterquarter section B, and quarter-quarter-quarter-quarter 

section D, inventory sequence 1. The fourth method is 

the well registration number (G-085442), which is 

assigned by the Nebraska Department of Natural 

Resources.

Nested-Well Construction

Sixty-nine nested wells were installed for this 

study between 1995 and 1999 (fig. 2). All nested wells 

consisted of one to three wells. Each well was constructed of 2.5-in., schedule-40 polyvinyl chloride 

(PVC) pipe with 0.010-in. slotted PVC well screen. 

All monitoring wells were installed using direct rotary 

methods and, in most instances, the deepest well of the 

nest was completed near or in the bedrock. Occasionally, because of the large size (typically cobbles) or the 

great thickness of the unconsolidated sediment, the 

test-hole drillers were unable to reach bedrock. In 

these instances, the deepest well was assumed to be 

near bedrock. Two wells (fig. 2, wells 2E-1 and 8C) 

are completed in the Brule Formation as uncased 

holes. Lithologic and driller's construction logs, and 

at some sites, electric logs, were collected at each site. 

Because bentonite was used to seal each well and bentonite can contain radon and uranium (two of the constituents in the water-quality samples), a test well

Field and Analytical Methods 13
Well number

24N 57W 15 CBBD1

Figure 3. Township-range-section numbering system.

14 Selected Field and Analytical Methods and Analytical Results in the Dutch Flats Area, Western Nebraska, 1995-99
(IB-2) was installed near a typical monitoring-well 

site (IB-1) to confirm that radon and uranium detections in ground-water samples were from the water 

and not from the bentonite. The test well was 

installed using direct-mud-rotary methods without a 

bentonite seal.

Sample-Collection Procedures

Samples were collected following USGS guidelines to ensure the collection of representative 

samples. On the basis of wells constructed, the flow of 

water through the canals, and the information collected the previous years, a yearly sampling scheme 

was developed. The sampling schemes included the 

constituents for which samples would be analyzed, a 

list of the collection sites, and frequency and timing of 

collection.

Surface-water samples were collected using equalwidth increment (EWI) sampling procedures or 

centroid-of-flow (COF) sampling procedures as 

described by Wells and others (1990). However, at the 

wetlands site near Morrill (site SW11, fig. 1), a dip 

sample was collected. COF samples were collected 

from both irrigation canal sites (SW1 and SW3, fig. 1). 

Water in these canals is considered well mixed (Steele 

and Cannia, 1997). EWI sampling was used at the 

remainder of the sites where the streamflow was not 

considered well mixed. All water-quality samples 

were collected by wading the stream or suspending the 

sampler by hand from a bridge. Samples subsequently 

were processed onsite by using protocols similar to 

those described by Wells and others (1990). Onsite 

measurements included specific conductance, pH, 

water and air temperature, and dissolved oxygen.

To obtain a representative ground-water sample, 

three casing volumes of water were removed from the 

well prior to the collection of a sample. Physical properties of specific conductance, pH, water temperature, 

and dissolved oxygen were measured at 5-minute 

intervals using a flow-through chamber. Samples were 

collected after these physical property values stabilized or after at least three casing volumes had been 

pumped out of the well.

Samples to be analyzed for major ions, nitrogen, 

and radon were collected, preserved, and transported 

in accordance with the methods described in Pritt and 

Jones (1990), Wells and others (1990), and Verstraeten 

and others (1995; 1999). Water samples were

processed and preserved onsite and analyzed at various USGS laboratories.

Discharge measurements for the Interstate Onal 

(site SW1) and Tri-State Canal (site SW3) were 

obtained from Wyoming Water Control Office pe^sonnel in Torrington, Wyoming. Discharge for the 

North Platte River at Wyoming-Nebraska State line 

(site SW2) and Horse Creek near Lyman (site SW6), 

which are active gaging stations, was estimated by 

using the gage height with the shift indicated by the 

most recent measurement and the current rating as 

described by Rantz (1982). Discharges for Dry Sheep 

Creek (site SW7), Sheep Creek (site SW8), the North 

Platte River at Morrill (site SW9), and Akers Draw 

(SW10) and were determined by making streamflow 

measurements as described by Carter and Davidian 

(1968) at the time of water-quality sample collection.

A total of 137 samples were collected from tH 

11 representative surface-water sites. The North F'atte 

River at Morrill (site SW9) was sampled most often, 

37 times from 1996 through 1999. In 1999, water 

samples from surface-water bodies contributing vater 

to the North Platte River in the study area, except the 

wetlands site (SW11), were collected to evaluate the 

sources of uranium in surface water (Verstraeten and 

others, 2001). A total of about 1,960 ground-water 

samples were collected from 1996 through 1999. The 

number of samples collected at a specific well varied 

from 1 at well 2T, constructed in 1999, to 36 at 

well 1C-3, constructed in 1994.

Analytical Methods

Water samples were analyzed at the USGS 

National Water Quality Laboratory (NWQL) in 

Denver, Colorado, and the USGS Dissolved-Gas, 

Chlorofluorocarbon, Isotope, and Uranium Research 

Laboratories in Reston, Virginia (table 3).

Major Ions and Nitrogen Species

Analyses of major ions and nitrogen species were 

completed at the USGS laboratory in Denver, CoV 

rado, using standard methods (Fishman and FriedTian, 

1989). Major ions were analyzed by inductively 

coupled plasma emission spectrometry (ICP). 

Dissolved nitrogen species were analyzed using colorimetric methods within 2 weeks of refrigerated 

storage, with the exception of a few surface-wate*- 

samples that were analyzed after several months of

Field and Analytical Methods 15
Table 3. Selected water-quality constituents, reporting levels, analytical methods, references for analytical metvods, and 

regulatory levels used for the study, Dutch Flats area, western Nebraska

[PMCL, Primary Maximum Contaminant Level; SMCL, Secondary Maximum Contaminant Level. Analytical method: ICP, inductively coupled plasma; 

UV, ultraviolet; IR, infrared; GC, gas chromatography; MS, mass spectrometry; AS, alpha particle spectrometry. NA, not applicable; mg/L, milligrams 

per liter; ng/L, micrograms per liter; pCi/L, picocuries per liter]

Constituents

Calcium"

MagnesiumSodium"

Potassium2

Sulfate as sulfate"

Chloride2

Fluoride2

Silica2

Ammonia as nitrogen2

Nitrite as nitrogen 2

Nitrite plus nitrate as nitrogen"

Ammonia and organic nitrogen2

Dissolved and suspended organic carbon2

Carbon dioxide gas3

Iron

Manganese"

Organic carbon, dissolved"

Nitrogen gas3

Argon gas~

Oxygen gas3

Methane gas~

Uranium concentration4

Uranium activity ratio5

Radon6

Reporting level

0.02 mg/L

0.004 mg/L

0.1 mg/L

0.1 mg/L

0.1 mg/L

0.1 mg/L

0.1 mg/L

0.1 mg/L

0.2 mg/L

0.01 mg/L

0.05 mg/L

0.1 mg/L

0.2 mg/L

Omg/L

10 ng/L

4.0 mg/L

0.33 mg/L

Omg/L

Omg/L

Omg/L

Omg/L

0 ± 0.03 to 0.3 ng/L

0± 0.01 to 0.10

70 pCi/L

Analytical method

ICP

ICP

ICP

ICP

ICP

ICP

ICP

ICP

Colorimetry

Colorimetry

Colorimetry

Colorimetry

Dohrman UV-promoted persulfate/IR

Head space GC

ICP

ICP

Dohrman UV-promoted persulfate/IR

Head space GC

Head space GC

Head space GC

Head space GC

ICP/MS or AS

AS

Scintillation

Regulatory 

levels1

NA

NA

NA

NA

250 SMCL

250 SMCL

2.0 SMCL

NA

NA

1PMCL

10 PMCL

(nitrate only)

NA

NA

NA

300 SMCL

50 SMCL

NA

NA

NA

NA

NA

30MCL

NA

300 MCL

^.S. Environmental Protection Agency (2000).

2Fishman and Friedman (1989).

3 Method is listed on Internet at http://water.usgs.gov/lab/dissolved.gas/Lab/index.html.

4U.S. Environmental Protection Agency (1994) or Thatcher and others (1977).

5Thatcher and others (1977).

6Whittaker and others (1989).

room-temperature storage by ion chromatography in 

the USGS laboratory in Reston, Virginia.

Dissolved Gases

Samples to be analyzed for dissolved gases were 

collected in 125 mL serum bottles with butyl rubber 

stoppers with no headspace and were sent to the USGS 

Dissolved-Gas Laboratory in Reston, Virginia. Lowpressure headspace was created in the laboratory by 

extracting approximately 8 percent of the water. Concentrations of argon, nitrogen, and methane gases 

were measured by gas chromatography (GC) on the

headspace (URL http://water.usgs.gov/lab/dissolvedgas). Results for samples analyzed within 2 months of 

refrigerated storage were similar to results for samples 

preserved with potassium hydroxide.

Chlorofluorocarbons

Samples to be analyzed for chlorofluorc carbons 

(CFCs) were collected in flame-sealed glass ampules 

under pure nitrogen headspace (Busenberg and 

Plummer, 1992). CFCs were extracted in the USGS 

CFC Laboratory in Reston, Virginia, using r purgeand-trap procedure and analyzed by gas chromatogra16 Selected Field and Analytical Methods and Analytical Results in the Dutch Flats Area, Western Nebraska, 1995-99
phy (http://water.usgs.gov/lab/cfc). Concentrations of 

CFC-11, CFC-12, and CFC-113 were converted to 

equilibrium partial pressures at local water-table altitudes at the equilibration temperatures indicated by 

argon and nitrogen gas concentrations. The partial 

pressures were compared to the atmospheric record to 

determine the apparent year of recharge (Plummer and 

Busenberg, 1999). Because some of the samples were 

from wells with long screens, potential effects of 

mixing were evaluated by comparison with tritium and 

helium isotope data (Cook and Bohlke, 1999).

Tritium, Helium, and Neon Isotopes

Samples to be analyzed for tritium (3H)/helium-3 

(3He) age determination were collected in flowthrough copper tubes that were crimp sealed onsite. 

Helium and neon were extracted for mass spectrometric analysis, then degassed aliquots were re-analyzed 

after several months to determine 3H concentrations 

from 3He ingrowth at the Lamont-Doherty Earth 

Observatory of Columbia University, Noble Gas Laboratory in Palisades, New York (Ludin and others, 

1998). The age of each ground-water sample (in years 

between the time of recharge and time of sampling) 

was assumed to be equal to the time indicated by 

decay of 3H to 3He in a closed system after adjustments for atmospheric gas contributions and for excess 

terrigenic helium (Schlosser and others, 1998) with an 

assumed 3He/helium-4 (4He) ratio of 2 x 10~8 

(Mamyrin and Tolstikhin, 1984). Temperatures used 

in the age calculations were determined from the concentrations of argon and neon, assuming those gases 

had only atmospheric sources. Adjustments for terrigenic helium were made only if the apparent 

concentrations of terrigenic 4He were more than 

5 percent of the total 4He concentrations; values less 

than 5 percent were considered to have large relative 

uncertainties and result in anomalous age adjustments. 

Further adjustments for mixing of old and young water 

components commonly were made using samples 

from wells with long open intervals or with screens 

that intersect the water table, especially in fractured 

rock aquifers (such as Plummer and others, 1999). In 

the current study, most of the wells had relatively short 

screens at discrete depths in the alluvial aquifer where 

stable isotope data indicated that mixing of water from 

different sources was not widespread. Some of the T -J

JH/ He and CFC data from wells with long screens 

near the water table were evaluated assuming piston 

flow (no mixing), or binary, linear, or exponential

mixtures (Vogel, 1967; Cook and Bohlke, 1999; 

Plummer and others, 1999).

Hydrogen and Oxygen Isotopes in Water

Samples to be analyzed for hydrogen and oxygen 

isotopes in water were collected in 60-mL glass 

bottles. At the USGS Stable Isotope Laboratory in 

Reston, Virginia, 2-mL aliquots were equilibrated with 

either hydrogen (for hydrogen isotopes) or carbon 

dioxide (for oxygen isotopes), which then were admitted to dedicated dual-inlet mass spectrometers. 

Hydrogen and oxygen isotope analyses were calibrated against analyses of laboratory reference water 

with known 52H and 518O values normalized to 

standard values of 0 and 0 for hydrogen and oxygen, 

respectively, in VSMOW (Vienna-Standard Mean 

Ocean Water), and -428 and -55.5 for hydrogen and 

oxygen, respectively, in SLAP (Standard Light 

Antarctic Precipitation) (Coplen, 1988). The data 

were evaluated by comparison to the "meteoric water 

line", 52H = 8 * 518O + d-excess (Craig, 1961; 

Dansgaard, 1964; International Atomic Energy 

Agency, 1981). Although the global average d-excess 

value in precipitation is +10, local precipitation may 

have different values of d-excess, and evaporation may 

produce arrays of values with slopes less than 8, or 

lower apparent values of d-excess (Gonfiantini, 1986; 

International Atomic Energy Agency, 1992).

Nitrogen Isotopes in Nitrate and Dissolved 

Nitrogen Gas

Samples to be analyzed for isotopes of nitrate 

were collected in 1 L plastic bottles and frozen. At the 

USGS Stable Isotope Laboratory, Reston, Virginia, 

aliquots were freeze dried at high pH, then loaded into 

pure silica glass tubes with CaO and Cu2O; the tubes 

were evacuated, sealed, baked at 850 °C, and coiled 

slowly (Bohlke and Denver, 1995). Purified N2 gas in 

the tubes was expanded into a dual inlet mass spectrometer and analyzed along with gas produced from 

dissolved nitrate standards prepared and analyzed as 

aqueous samples. Nitrate 5 15N data were normalized 

to standard values of +4.7 for International Atomic 

Energy Agency (IAEA)-N3 and +180.0 for USGS-32 

(Bohlke and Coplen, 1995). For nitrogen isotop?- analysis of dissolved N2, the headspace gases remaining 

after gas chromatographic analysis at the USGS 

Dissolved Gas Laboratory in Reston, Virginia, were 

sealed into evaculated glass tubes with CaO and Cu2O,

Field and Analytical Method ~ 17
baked, cooled slowly, then admitted to the mass 

spectrometer and analyzed along with air samples 

(815N = 0) and with headspace samples from laboratory-equilibrated water samples (815N = +0.65 ±0.10). 

The overall accuracy and precision of the N2 isotope 

analyses were estimated to be approximately +0.2 or 

better for nitrate and +0.1 or better for N2 (Bohlke and 

Coplen, 1995).

Uranium and Uranium Activity Ratios

Water samples to be analyzed for dissolved uranium were collected in polyethylene bottles, filtered, 

and acidified. Two different techniques were used to 

analyze for uranium concentrations and the uranium 

isotopic ratio 234U/238U or uranium activity ratio 

(UAR). The two techniques, alpha particle 

spectroscopy (AS) and ICP/mass spectrometry (MS), 

were performed at the USGS Uranium Research Laboratory in Reston, Virginia. To analyze the dissolution 

of uranium from sediment samples, a representative 

1-g sample was leached for about 24 hours in 500 mL 

distilled water containing 0.5 g sodium bicarbonate.

For AS analyses, a 500-mL aliquot was taken, 

spiked with uranium-232 (232U), processed by iron 

hydroxide precipitation and anion-ion exchange, and 

then electroplated onto a stainless-steel planchette for 

counting, using a solid-state, partially depleted silicon 

detector (Ivanovich and Murray, 1992). The second 

method, using ICP/MS, was developed during the 

course of this investigation and allowed a more precise 

determination of uranium and UAR values on a 

smaller volume of sample (Thomas F. Kraemer and 

Michael W. Doughton, U.S. Geological Survey, 

written commun., 2000) than AS. In this method, uranium concentrations in the sample were determined 

first using uranium-236 (236U) as an internal standard. 

Upon determining the concentration, a measured 

volume of sample was selected for 234U/238U analysis 

that would produce acceptable ICP/MS performance. 

The volume of water was evaporated to dryness and 

redissolved in a 8N (normal) hydrochloric acid (liquid 

phase) solution. The uranium then was separated by a 

simple anion-exchange procedure. The uranium was 

eluted into a 30-mL bottle with 0. IN hydrogen 

chloride and distilled water, which then was injected 

into the ICP/MS unit using an ultrasonic nebulizer. 

Precision and accuracy for the uranium analyses by 

AS were approximately 3 percent and, for UAR by 

AS, were 5 to 7 percent. Using the ICP/MS technique,

the precision and accuracy were less than 1 and 

0.5 percent, respectively.

Calculation of Recharge Temperatures, Excess 

Air, and Excess Nitrogen in Ground Water

The apparent recharge temperature and amount of 

excess air were calculated for each sample from the 

concentrations of argon and neon by assuming two 

dissolved-gas components (Aeschbach-Herig and 

others, 1999; Stute and Schlosser, 1999): (1) from air 

equilibration at the altitude of the water tab'e and 

100 percent relative humidity; and (2) from unfractionated excess air introduced during recharge or 

sampling. This calculation was done for ea~h sample 

by solving iteratively an equation relating th~. 

measured concentrations of argon and neon to a 

common equilibration temperature and excess air 

quantity:

Excess air ccSTP/L= {[Ar]measuared - [Ar(T,ehv)]asw }/ 

0.417mnolAr/ccair = {[Ne]meas -[Ne(T,elev)]asw }/

0.000811 (nmolNe )/cca (1)

where 

ccSTP/L

[Ar,Ne]meas

is cubic centimeters per liter at 

standard temperature and 

pressure;

is the measured concentration of 

argon or neon in the sample (in 

micromoles per liter (nmol/L); 

and

[Ar,Ne(T,elev)] asw is the concentration of argon or 

neon in air-saturated water at the 

temperature and altitude of the 

water table (calculated using 

argon and neon solubility data 

fromWeiss, 1970,1971).

For comparison with the argon and neon data, the 

apparent recharge temperature and amount of excess 

air also were calculated similarly for each sample from 

the concentrations of argon and nitrogen, w: th nitrogen solubility data from Weiss (1970). For samples 

with relatively high oxygen concentrations, recharge 

temperatures and excess air quantities calculated from 

argon and neon data and from argon and nitrogen data 

generally were in agreement to within the uncertainty 

of the methods. However, for some of the samples 

with low oxygen concentrations (less than 50 jbimol/L),

18 Selected Field and Analytical Methods and Analytical Results in the Dutch Flats Area, Western Nebraska, 1995-99
there was disagreement between the two calculations 

that could be accounted for by assuming that the oxygen-depleted samples contained an additional nonatmospheric component of nitrogen.

Therefore, concentrations of excess nitrogen were 

calculated for each sample by using the recharge temperature and excess air values derived from argon and 

neon data:

Excess N0 in ^ ; = [N0 ]meas-[N0 (T,elev)]

z L z z asw

[Excess air in ccSTP/L]* 34.8 pimol N2/ccair . (2)

Results indicate that the practical detection limit for 

excess nitrogen was approximately 18 jimol/L.

Quality Assurance and Quality Control

USGS onsite and laboratory quality-assurance 

(QA) and quality-control (QC) guidelines were 

followed throughout this study. These guidelines are 

necessary to assess whether or not contamination 

occurred and, if present, whether it occurred onsite or 

in the laboratory. Therefore, 134 QC samples 

(6.5 percent of the total 2,092 samples) were collected. 

QC samples collected onsite included 58 equipment 

blanks, 75 duplicates, and 1 spiked sample (Inorganic 

PotableWatR , Lot No. 3423). Each USGS laboratory follows stringent QA/QC procedures, dependent 

on the analytical method used for chemical analysis. 

In addition, cation-anion balances of all samples analyzed for major ions were checked by comparing 

them.

ANALYTICAL RESULTS

This section lists selected analytical results not 

published in previous USGS reports (tables 4 through 

7). Specifically, dissolved gases, age-dating data, and 

other isotopes collected as part of an intensive 

sampling effort in August and November 1998 and all 

uranium and uranium isotope data collected through 

the course of this study (1995 to 1999) have been 

included in these tables.

With respect to QA/QC of the cation/anion balances, all samples were rated as acceptable because 

they were within 10 percent of each other. Analytical 

results of equipment blanks for major ions and nitrate

concentrations generally were acceptable. Nitrateconcentrations in blank samples varied from less than 

the detection level of 0.05 mg/L as nitrogen (26 of 

58 samples or 45 percent) to 0.30 mg/L as nitrogen. 

All but two blank samples had concentrations less than 

0.10 mg/L as nitrogen.

The differences in nitrate concentrations between 

the 60 environmental samples and their duplicate 

samples varied from 0 (0 percent) to 5.0 mg/L 

(38 percent) with a median of 0.19 mg/L (1.7 percent). 

All but one set of replicate samples had a difference in 

concentration less than 0.50 mg/L, with larger differences generally observed at larger nitrate concenfations. A Wilcoxon rank-sum test indicated that these 

differences were not statistically significant (60 sets of 

replicates with p-value of 0.6782). Using a 95-percent 

confidence interval, p-values of 0.05 or less indicate 

that the medians of the populations being considered 

are significantly different. The nitrate concentration in 

the spiked reference sample was 7.6 mg/L instead of 

the expected 7.5 mg/L, a difference of 1.4 percen*, or 

0.10 mg/L. This analytical result is well within th". 

acceptable performance limit for nitrate.

To investigate whether the use of bentonite in 

well-construction materials would affect the cheiristry 

of the ground-water samples, especially the amounts 

of radon and uranium, well IB-2 was sampled twice 

(generally within 0.5 hour) when well IB-1 was 

sampled. Samples from these two wells were an?- 

lyzed for radon (two samples), uranium (one samnle), 

and nitrate (two samples) among other constituents, 

depending upon the particular sample collection. 

Comparison of the water chemistry between 

well IB-1 and well IB-2 indicated that well 

construction with bentonite did not affect the activity 

of radon present in the water. The differences in 

analytical results for radon were 16 (5 percent) and 

53 (15 percent) pCi/L, both less than or near the analytical error of two standard deviations of 22 and 

21 pCi/L, respectively. The differences in uranium 

concentrations were 0.9 jig/L or 6 percent. The differences in nitrate concentrations were 0.61 (19 percent) 

and 0.49 mg/L (5 percent). These results indicate that 

the use of bentonite in well construction did not affect 

the ground-water chemistry of the samples collected, 

but that small variations in ground-water chemist-y 

can occur over short distances.

Analytical Results 19
Table 4. Water temperature, dissolved oxygen, and dissolved-gas concentrations, and calculated recharge temperat

excess nitrogen in surface- and ground-water samples from selected sites, Dutch Flats area, western Nebraska, 1998 

[mo, month; d, day; yr, year; °C, degrees Celsius; mg/L, milligrams per liter; (iM/L, micromoles per liter; ft, feet; m, meters; ccSTP/L, cubic cent

temperature and pressure (for gases, this means 0 °C and 1 atmosphere); --, no data]

2!

CD

a 

a

3

s.

0

SL

Dissolved gases

Sample

Map index date

number (mo/

(figs. 1 and 2) d/yr)

Water

temperature

(°C)

Dissolved

oxygen,

(mg/L)

Nitrogen,

N2

(mg/L)

Argon, Ar

(mg/L)

Carbon

dioxide, Methane,

CO2 CH4

(mg/L) (mg/L)

Landsurface

altitude

(ft above

sea

level)

Landsurface

altitude

(m above

sea level)

Recharg

temper

ture (°C

If Surface-water samples

0

a

(A

3

a

1n

SL

3) 

CD 

(A

c.

(A5'

SWl 8/25/98

SW3 8/25/98

(field duplicate) 8/25/98

SW9 8/25/98

9/1/98

(field duplicate) 9/1/98

11/12/98

(field duplicate) 11/12/98

21.7

21.2

21.2

20.2

21.5

21.5

-

-

-

7.1

7.1

7.5

..

~

13.9

13.9

12.34

12.83

12.99

13.34

13.25

13.24

18.71

18.53

0.456

.474

.476

.494

.493

.491

.682

.681

4.28 0

6.18 0

6.02 0

6.92 0

6.89 0

6.70 0

9.13 0

9.26 0

4,020

4,010

4,010

3,972

3,982

3,982

3,972

3,972

1,255

1,222

1,222

1,211

1,214

1,214

1,211

1,211

22.9

21.1

~

19.2

-

4.9

~

c* Ground-water samples

CD

0

3"

 n

»

w

1

1(A

z

s1

i

r

1A-1 8/28/98

1A-3 8/27/98

IB-1 9/2/98

1C-1 8/24/98

1C-2 8/27/98

1C-3 8/24/98

ID-1 9/2/98

ll>-2 9/2/98

IE-1 8/24/98

IE-2 8/24/98

IE-3 8/24/98

20.5

18.0

14.0

14.5

15.0

14.2

14.5

16.0

14.0

14.0

13.5

6.2

7.5

7.9

10.0

14.5

12.8

4.8

5.0

6.1

7.1

7.0

14.55

15.63

15.12

16.04

16.22

16.52

17.93

16.58

17.93

17.01

17.62

.526

.572

.552

.570

.570

.582

.616

.576

.615

.599

.616

11.8 0

11.4 0

22.6 0

8.87 0

13.7 0

20.6 0

9.63 0

13.8 0

9.80 0

17.5 0

25.2 0

4,205

4,205

4,162

4,139

4,139

4,139

4,100

4,100

4,094

4,094

4,094

1,282

1,282

1,269

1,262

1,262

1,262

1,250

1,250

1,248

1,248

1,248

18.6

14.4

14.4

14.4

14.8

13.0

12.6

14.8

12.6

12.5

12.2

1F-1 9/1/98 15.0 7.3 15.87 .580 28.1 4,080 1,244 12.8 
Table 4. Water temperature, dissolved oxygen, and dissolved-gas concentrations, and calculated recharge temperatu

excess nitrogen in surface- and ground-water samples from selected sites, Dutch Flats area, western Nebraska, 1998 

Dissolved gases

Map index 

number 

(figs. 1 and 2)

Sample 

date 

(mo/ 

d/yr)

Water 

temperature 

(°C)

Dissolved 

oxygen, 

(mg/L)

Nitrogen, 

N2 

(mg/L)

Argon, Ar 

(mg/L)

Carbon 

dioxide, 

CO2 

(mg/L)

Methane, 

CH4 

(mg/L)

Landsurface 

altitude 

(ft above 

sea 

level)

Landsurface 

altitude 

(m above 

sea level)

Recharge 

temperature (°C)

Ground-water samples Continued

1G-1

1G-3

1H-1

1H-2

11-1

11-3

U-l

1J-2

1J-3

11^1

11^2

11^3

1M-1

1M-2

1M-3

2A-1

2B-1

2B-2

2B-3

8/27/98

8/27/98

9/1/98

9/1/98

8/28/98

8/28/98

9/1/98

11/12/98

9/1/98

11/12/98

9/1/98

11/12/98

8/25/98

8/25/98

8/25/98

8/31/98

8/31/98

8/31/98

8/26/98

8/26/98

8/26/98

8/26/98

14.0

12.5

15.0

14.5

12.5

11.5

15.5

-

15.0

--

14.0

--

12.0

12.0

12.5

14.0

14.0

13.5

14.0

15.0

17.0

18.0

7.3

5.6

.3

6.6

2.3

1.4

1.1

1.3

3.0

.1

3.0

4.4

.1

.1

0

4.8

7.3

4.5

8.4

8.1

6.6

8.4

15.48

15.90

20.57

19.19

18.52

17.86

17.38

18.44

16.53

17.19

16.05

16.41

19.07

17.87

16.61

16.21

16.63

18.04

16.09

15.37

14.41

14.75

0.573

.580

.615

.618

.610

.608

.586

.586

.566

.578

.574

.577

.611

.604

.576

.565

.589

.611

.581

.565

.520

.518

27.9

26.4

8.27

14.5

20.8

27.6

11.7

11.6

24.7

25.0

31.2

32.1

12.7

19.0

48.5

11.2

30.3

42.7

11.2

9.21

9.05

8.90

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

4,016

4,016

3,990

3,990

3,991

3,991

3,992

3,992

3,992

3,992

3,992

3,992

3,980

3,980

3,980

4,110

4,110

4,110

4,225

4,202

4,202

4,202

1,224

1,224

1,216

1,216

1,216

1,216

1,217

1,217

1,217

1,217

1,217

1,217

1,213

1,213

1,213

1,253

1,253

1,253

1,288

1,281

1,281

1,281

13.3

12.7

13.8

16.4

16.1

12.2

14.2

14.2

15.2

-

13.4

-

11.8

13.6

--

15.3

13.0

--

14.8

13.0

18.0

19.3
Table 4. Water temperature, dissolved oxygen, and dissolved-gas concentrations, and calculated recharge temperatu

excess nitrogen in surface- and ground-water samples from selected sites, Dutch Flats area, western Nebraska, 1998 

o Dissolved gases

:ted Fildand Aal

Map index 

number 

(figs. 1 and 2)

Sample 

date 

(mo/ 

d/yr)

Water 

temperature

Dissolved 

oxygen, 

(mg/L)

Nitrogen, 

N2 

(mg/L)

Argon, Ar 

(mg/L)

Carbon 

dioxide, Methane, 

CO2 CH4 

(mg/L) (mg/L)

Landsurface 

altitude 

(ft above 

sea 

level)

Landsurface 

altitude 

(m above 

sea level)

Recharg

tempera

ture (°C)

"5. Ground-water samples Continued

I

2

(D

 ?

O

Q.

W

D>

3

Q.

3

 ^

o'

SL

3D

5?

5'

(D

D

3-

Tl

§

(D

0)

*

1

Z

1

ws«r

0)

(O

$

8

2D-1

2D-2

2D-3

2E-1

2H-1

2H-2

2J-1

2J-2

2J-3

21^1

2L-2

2T

61

7A-1

10K-1

IK-94-1

IK-94-2

26K-94-1

26K-94-2

C. Morrill

8/27/98

8/27/98

8/27/98

8/26/98

9/1/98

9/1/98

8/31/98

8/31/98

8/31/98

9/2/98

9/2/98

7/13/99

8/26/98

8/23/99

7/13/99

8/25/98

8/25/98

9/1/98

9/1/98

8/31/98

12.5

15.5

14.5

13.5

14.5

14.0

14.0

13.5

13.5

12.5

12.0

14.0

12.0

14.8

20.0

18.0

18.0

13.0

13.0

17.5

5.1

4.7

6.8

7.3

9.5

5.4

.1

1.0

4.6

.1

0

.2

1.4

5.5

7.7

.3

.3

.1

.1

0

16.28

15.57

16.42

16.08

15.68

17.00

16.02

16.75

16.52

17.49

17.24

21.99

17.84

18.13

18.88

16.85

16.50

20.62

20.58

22.62

0.567

.549

.577

.582

.568

.588

.545

.588

.593

.605

.591

.584

.618

.623

.642

.568

.558

.681

.680

.662

9.10 0

15.9 0

27.9 0

6.66 0

28.3 0

28.4 0

9.30 0

19.3 0

33.3 0

12.7 0

20.5 0

.03 8.315

3.63 0

5.73 0

5.45 .0196

9.19 .0112

9.14 .0114

36.7 .3245

36.8 .3199

3.36 .9598

3,991

4,137

4,137

4,248

4,010

4,010

3,995

3,995

3,995

3,982

3,982

4,100

4,054

4,196

4,100

3,986

3,986

3,987

3,987

4,050

1,216

1,261

1,261

1,295

1,222

1,222

1,218

1,218

1,218

1,214

1,214

1,250

1,236

1,279

1,250

1,215

1,215

1,215

1,215

1,234

15.5

16.1

14.0

12.2

14.2

14.1

16.4

13.5

12.1

10.7

13.1

12.3

12.1

13.8

11.5

11.8

--

7.0

--

5.9
Table 5. Nitrogen, hydrogen, oxygen, and helium isotopes in surface- and ground-water samples from selected sites, Dutch Flats are

western Nebraska, 1998 through 1999

[mo, month; d, day; yr, year; ft, feet; m, meter; 8, delta-the difference relative to the standard, in parts per thousand; per mil, parts per thousand; TU, tritium unit; ccS

standard temperature and pressure (for gases, this means 0 degrees Celsius and 1 atmosphere); H2O 

than]

Map index number 

(figs. 1 and 2)

Sample 

date 

(mo/d/yr)

Water- Watertable table 

alti- altitude tude 

(ft) (m)

Nitrate, 

815NN03- 

(per mil)

Water, 

82HH20 

(per 

mil)

, water; %, percent; JH°, initial tritium (equals JH plus tritiogeni

Water, 3H 

818O- (TU) 

H2O from 

(per tube 

mil) (±2%)

3H 

(TU) 

from 

bottle

(±2%)

3H 

(TU) 

used 

forage

(±2%)

Neon, 

Ne (total) 

(ccSTP/g) 

(±1%)

Surface-water samples

SWl

SW3

SW9

8/25/98

8/25/98

8/25/98

11/12/98

4,209 1,283

4,006 1,221

3,973 1,211

--

8.21

7.70

7.70

-115.0

-112.5

-111.4

-111.6

-14.28 13.2

-14.02 15.4

-13.72

-13.75 24,2

12.6

15.9

17.9

24.2

13.2

15.4

17.9

24.2

1.60x 10'7

1.64X10'7

1.65xlO'7

1.90xlO"7

Ground-water samples

1A-1

1A-3

IB-1

1C-1

1C-2

IC-3

ID-1

ID-2

IE-1

IE-2

IE-3

1F-1

IG-1

IG-3

8/28/98

8/27/98

9/2/98

8/24/98

8/27/98

8/24/98

9/2/98

9/2/98

8/24/98

8/24/98

8/24/98

9/1/98 '

8/27/98

8/27/98

4,134 1,260

4,134 1,260

4,111 1,253

4,098 1,249

4,098 1,249

4,098 1,249

4,088 1,246

4,088 1,246

4,075 1,242

4,075 1,242

4,075 1,242

4,058 1,237

4,012 1,223

4,012 1,223

--

--

4.63

4.46

4.15

3.60

5.70

3.11

4.08

2.67

2.94

3.67

2.53

2.42

-119.2

-117.4

-118.6

-110.3

-113.5

-111.2

-118.4

-117.8

-118.3

-116.7

-113.3

-115.0

-114.3

-M3.8

-14.60 11.7

-14.74 13.0

-14.70 12.6

-13.71 11.6

-14.01 13.1

-13.68 14.9

-14.83

-14.47 31.3

-14.57 79.0

-14.36 37.3

-14.10 18.1

-14.16 12.9

-14.11 15.8

-14.01 15.3

12.1

12.9

13.1

11.0

13.6

14.4

48.6

32.4

81.8

36.6

18.3

13.2

15.5

11.7

13.0

12.6

11.6

13.1

14.9

48.6

31.3

79.0

37.3

18.1

12.9

15.8

15.3

1.99xlO'7

2.06x1 0'7

1.84xlO'7

2.03xlO'7

2.08xlO'7

2.00xlO'7

2.32xlO'7

2.14xlO'7

2.31xlO-7

2.l3xlO-7

2.27x1 0'7

1.95xlO'7

1.92xlQ-7

1.93xlO'7
Table 5. Nitrogen, hydrogen, oxygen, and helium isotopes in surface- and ground-water samples from selected sites, Dutch Flats area

western Nebraska, 1998 through 1999-Continued

w

(D 

(D O

0.

31 Map index number 

| (figs. 1 and 2)

0)

a

> IH-l

1 IH- 2

o

SL

» U-l

(0

E 1 1-3

w5'

(0 ' *"'

? U-l

1 U-2

ft 1J-2

> 1J-3

3

» U-3

(0

(0

» 1L-1

3

2 1L-2

(0

3 1L-3

wpr

D)

3 1M-1

<oS 1M-2

<o

1M-3

Sample 

date 

(mo/d/yr)

Watertable 

altitude 

(ft)

Watertable Nitrate, 

alti- 815Ntude NO3" 

(m) (per mil)

Water, 

S2HH20 

(per 

mil)

Water, 

8180- 

H20 

(per 

mil)

3H 

(TU) 

from 

tube 

(±2%)

3H 3H 

(TU) (TU) 

from used 

bottle for age 

(± 2%) (±2%)

Neon, 

Ne (total) 

(ccSTP/g) 

(±1%)

(

Ground-water samples Continued

9/1/98

9/1/98

8/28/98

8/28/98

9/1/98

11/12/98

9/1/98

11/12/98

9/1/98

11/12/98

8/25/98

8/25/98

8/25/98

8/31/98

8/31/98

8/31/98

3,980

3,980

3,983

3,983

3,976

3,976

3,976

3,976

3,976

3,976

3,970

3,970

3,970

4,094

4,094

4,094

11.51

3.98

1.95

2.03

5.41

5.36

3.83

3.65

3.31

3.01

10.20

7.98

-

5.37

4.10

2.98

-114.0

-113.3

-112.2

-112.4

-112.8

-111.3

-108.0

-108.1

-113.4

-111.8

-114.5

-113.6

-112.1

-118.2

-111.5

-112.7

-14.37

-13.90

-13.79

-13.90

-13.84

-13.78

-13.25

-13.25

-13.89

-13.91

-14.14

-14.06

-13.80

-14.57

-13.67

-13.84

25.5

19.3

27.9

16.9

24.0

24.5

19.9

20.1

17.7

16.4

39.7

33.0

29.5

15.5

14.6

27.0 25.5

19.2 19.3

18.9 18.9

16.6 16.9

24.6 24.0

25.6 24.5

20.1 19.9

20.0 20.1

17.7 17.7

17.3 16.4

40.0 40.0

39.7 39.7

32.8 32.8

27.4 27.4

15.5

13.7 13.7

2.44xlO'7

2.76x1 0'7

2.63xlQ-7

2.17xlO"7

2.17xlO'7

2.20xlO'7

2.06x1 0'7

-

1.93xIO'7

--

2.17xlO'7

2.29x1 0'7

-

2.07x1 0'7

2.08x1 0'7

-

7

7

7

4

4

8/26/98 4,137 3.30 -108.5 -13.89 6.3 6.3 2.20xlO'7 

2B-1

2B-2 

2B-3

8/26/98

8/26/98

8/26/98

4,134

4,134

4,134

3.75

6.07

-

-107.1

-117.8

-117.4

-13.50

-14.61

-14.53

4.3

12.4

12.9

3.8

13.1

13.2

4.3

13.1

12.9

1.83xlQ-7

1.87xlO'7

1.97xlO'7
Table 5. Nitrogen, hydrogen, oxygen, and helium isotopes in surface- and ground-water samples from selected sites, Dutch Flats are

western Nebraska, 1998 through 1999-Continued

Map index number 

(figs. 1 and 2)

Sample 

date 

(mo/d/yr)

Watertable 

altitude 

(ft)

Watertable Nitrate, 

alti- 815Ntude NO3" 

(m) (per mil)

Water, 

82HH2O 

(per 

mil)

Water, 

8180- 

H2O 

(per 

mil)

3H 

(TU) 

from 

tube

(±2%)

3H 3H 

(TU) (TU) 

from used 

bottle for age

(±2%) (±2%)

Neon, 

Ne (total) 

(ccSTP/g) 

(±1%)

Ground-water samples Continued

2D-1

2D-2

2D-3

2E-1

2H-1

2H-2

2J-1

2J-2

2J-3

2L-1

2L-2

2T

6I

7A-1

3 10K-1 

H.

o'

H. IK-94- 1

V)

£ 26K-94-1

w C. Morril!

8/27/98

8/27/98

8/27/98

8/26/98

9/1/98

9/1/98

8/31/98

8/31/98

8/31/98

9/2/98

9/2/98

7/13/99

8/26/98

8/23/99

7/13/99

8/25/98

9/1/98

8/31/98

4,104

4,104

4,104

4,216

4,014

4,014

3,980

3,980

3,980

3,976

3,976

3,970

4,045

4,173

3,967

3,976

3,973

4,003

4.87

5.61

5.71

3.96

-.47

-.54

4.91

3.90

2.34

11.19

5.60

3.47

5.35

4.45

3.00

-

-

-117.4

-117.4

-113.3

-110.7

-113.8

-113.8

-112.5

-111.3

-112.0

-114.6

-115.4

-108.3

-107.0

-113.7

-92.4

-106.9

-100.7

-109.0

-14.82

-14.28

-14.02

-14.61

-14.12

-14.05

-13.85

-13.70

-13.62

-14.28

-14.17

-13.90

-13.07

-14.39

-11.68

-13.61

-12.09

-14.33

-

21.1

17.1

..

14.5

14.7

24.2

25.6

19.1

30.4

35.1

-

-

23.3

3.5

.4

21.6

.1

25.4 25.4

19.5 21.1

16.1 17.1

4.5 4.5

14.7 14.5

14.0 14,7

23.7 24.2

24.3 25.6

18.5 19.1

30.4

35.1 35.1

17.0 17.0

24.9 24.9

24.4 23.3

4.5 3.5

.2 .4

21.7 21.6

.2 O.I

2,l2xlO'7

1.98xlO'7

2.06x1 0'7

1.92xlO'7

1.97xlO'7

2.18xlO'7

1.96xIQ-7

2.10xlO~7

1.99xlQ-7

1.95xlO'7

2.08x1 0'7

-

2.27x1 0-7

2.55x1 0'7

2.45x1 0"7

1.62XIO'7

2.24x1 0'7

1.74xlO'7
Table 5. Nitrogen, hydrogen, oxygen, and helium isotopes in surface- and ground-water samples from selected sites, Dutch Flats area

western Nebraska, 1998-Continued

Uncorrected for terrigenic helium

Map index number 

(figs. 1 and 2)

Sample 

date 

(month/ 

day/yr)

3He, 

tritogenic 

(TU)

age

(yr)

5 ±3H/3He 

age

(yr)

3Ho 

(TU)

Corrected for terrigen

4He, 

terrigenic 

(ccSTP/g)

4He, 

terrigenic 

(% of 

total 

He)

3He, 

tritiogenic 

(TU)

Surface-water samples

SWl

SW3

SW9

8/25/98

8/25/98

8/25/98

11/12/98

-0.2

-.2

.4

.3

-0.2

-.2

.4

.3

0.1

.1

.1

.1

13.0

15.2

18.3

24.5

7.77x10-"

-2.16x10"'°

6.12x10-'°

4.68x1 (T 10

0

-1

2

1

-0.2

-.4

.7

.5

Ground-water samples

1A-1

IA-3

IB-1

IC-1

1C-2

IC-3

ID-1

ID-2

IE-1

IE-2

IE-3

1F-1

1G-I

1G-3

8/28/98

8/27/98

9/2/98

8/24/98

8/27/98

8/24/98

9/2/98

9/2/98

8/24/98

8/24/98

8/24/98

9/1/98

8/27/98

8/27/98

-31.8

-.1

.2

3.7

2.6

2.1

156.6

65.4

362.6

78.1

6.4

.1

1.6

2.5

-

-.1

.3

5.0

3.2

2.3

25.8

20.2

30.9

20.2

5.4

.2

1.8

2.7

"

.2

.1

.2

.2

.1

.3

.3

.2

.3

.1

.1

.1

.1

-

12.9

12.9

15.3

15.7

17.0

205.2

96.7

441.6

115.4

24.4

13.0

17.4

17.8

6.85xlO'8

-6.40x1 0' 10

4.57x10-"

1.28xlO'8

5.25xlO'9

2.56x1 0'9

4.97x1 0"8

3.73x1 0'9

3.23x1 0'8

1.85xlO'9

1.77x10-"

-4.97x1 0' 10

1.34X10'9

7.03xIO-'°

58

-1

0

21

9

5

46

7

36

3

0

-1

3

I

5.7

-.5

.2

10.6

5.3

3.4

183.7

67.3

380.2

79.0

6.3

-.2

2.3

2.8
ro

-4

Table 5. Nitrogen, hydrogen, oxygen, and helium isotopes in surface- and ground-water samples from selected sites, Dutch Flats area, 

western Nebraska, 1998-Continued

Uncorrected for terrigenic helium

CO 

(D 

(D 

O

ST 

a

to Map index number

£ (figs. 1 and 2)

o>

3

a

to

1 1H-2

o

SL

i 1M

ff 11-3

5'

n U-l 

D

1 1J-I

TI U-2

ff U-2

3 U-3

^ 1J-3

(D 

(A

i? 

3 1L-1

I 1L-2

3 iii 

w ILj -'

X

p>

8 1M-1 

en

S 1M-2

1 M-3

Sample 

date 

(month/

day/yr)

3He, 

tritogenic

(TU)

3H/3He 

age

(yr)

±3H/3He 

age

(yr)

3Ho

(TU)

Corrected for terrigeni

4He, 

terrigenic

(ccSTP/g)

4He, 

terrigenic 

(% of 

total

He)

3He, 

tritiogenic

(TU)

Ground-water samples Continued

9/1/98

9/1/98

8/28/98

8/28/98

9/1/98 

11/12/98

9/1/98

11/12/98

9/1/98

11/12/98

8/25/98

8/25/98

8/25/98

8/31/98 

8/31/98

8/31/98

16.3

6.7

13.8

3.4

7.0 

6.2

10.5

-

2.4

-

79.4

-38.9

--

45.2 

5.4

8.9

5.3

9.8

3.3

4.6 

4.0

7.6

--

2.3

-.

19.6

..

-

17.5 

5.4

..

0.3

.2

.2

.1

.1 

.1

.2

-

.1

,-

0.2

--

-

.2 

.1

41.8

25.9

32.7

20.3

31.0 

30.7

30.3

~

20.1

--

119.3

-

-

72.6 

20.9

..

1.52X10'7

1.34xlO'9

8.33x1 0'9

-2.81x10-'°

I.SSxIO'8 

l.92xlO'8

-1.12xlO'9

-

-J.46xlO'9

-

9.47x1 0'9

1.38xlO'7

-

4.40x1 0'9 

-1.31xlO'9

..

71

2

11

-1

26 

26

-2

..

-3

-

15

71

-

8 

-3

..

99.8

7.3

18.2

3.1

17.2 

16.6

9.7

«

1.5

-

84.5

36.6

~

47.5 

4.6

2A-1 8/26/98 -3.2 8.40xIO'9 13 1.3 

2B-1 

2B-2 

2B-3

2D-I 

2D-2 

2D-3

8/26/98

8/26/98

3/2^/93

8/27/98

8/27/98

8/27/98

-7.2

-.2

-3.2

47.8

18.4

2.9

-

-.3

-

19.0

11.3

2.8

-

.1

--

.2

.2

.1

--

12.9

-

73.3

39.5

20.0

1.49xlO'8

2.37xlO' 10

8.62x1 0'9

1.49xlO"8

1.25xlO'9

-6.93x10-'°

25

I

15

22

3

-1

.9

-.2

1.4

55.9

19.0

2.4
Table 5. Nitrogen, hydrogen, oxygen, and helium isotopes in surface- and ground-water samples from selected sites, Dutch Flats area, 

western Nebraska, 1998-Continued

Uncorrected for terrigenic helium

Analytical

,9

C

5?

Map index number 

(figs. 1 and 2)

2E-1

2H-1

2H-2

2J-1

2J-2

2J-3

2L-1

2L-2

2T-I

61

7A-1

10K-I

IK -94-1

26K-94-1

C. Morrill

Sample 

date 

(month/ 

day/yr)

8/26/98

9/1/98

9/1/98

8/31/98

8/31/98

8/31/98

9/2/98

9/2/98

7/13/99

8/26/98

8/23/99

7/13/99

8/25/98

9/1/98

8/31/98

3He, 

tritogenic 

(TU)

-309.0

1.2

1.2

22.9

15.9

3.6

5.3

43.7

-

4.6

55.9

-356.4

-840.1

1.2

--

3H/3He ±3H/3He 

age age 3H° 

(yr) (yr) (TU)

Ground-water samples Continued

_

1.4 0.1 15.7

1.4 .1 15.9

11.9 .2 47.1

8.7 .2 41.5

3.1 .1 22.7

2.9 .2 35.6

14.5 .2 78.8

-

3.1 .1 29.5

22.0 .3 79.2

-

1.0 .1 22.8

-

Corrected for terrigenic 

4He, 

terrigenic 

(ccSTP/g)

5.72x1 0"7

2.94xlO'9

3.95xlO' 10

l.OlxlQ-8

-2.90xlO' 10

-1.57xlO-9

1.16xlO-7

3.88x1 0'8

--

2.42x1 0'8

6.76xlO'8

5.81xlO'7

1.52xlO'6

3.17X10'9

--

4He,

terrigenic 

(% of 

total 

He)

93

6

1

17

-1

-3

72

43

--

30

51

91

98

6

--

3He, 

tritio- 

genie 

(TU) 

4.4 

2.7 

1.3 

28.3 

15.7 

2.6 

68.8 

64.9 

--

17.8 

92.9 

-37.9

-7.8

2.9 

--
Table 6. Chlorofluorocarbons in surface- and ground-water samples from selected sites, Dutch Rats area, western 

Nebraska, 1998

[mo, month; d, day; yr, year; CFC, chlorofluorocarbon; pg/kg, picograms per kilogram; a, sigma-the standard deviation; , no data]

Map index

number 

(figs. 1 and 2)

Sample date 

(mo/d/yr)

CFC-11 

(P9/k9)

CFC-11

(pg/kg)

CFC-12

(pg/kg)

±1o 

CFC-12 

(pg/kg)

CFC-113

(pg/kg)

±1o 

CFC-113

(pgAcg)

Age, suggested, 

CFC data

(yr)

SW9

Surface-water sample

8/25/98 424.2 2.3 212.8 15.9

Ground-water sanples

59.7 11.0 Modem water

IE-1

IE-2

U-l 1

1J-21

IJ-3

1M-1

1M-2

1M-3

8/24/98

8/24/98

9/1/98

9/1/98

9H/98

8/31/98

8/31/98

8/31/98

66.4

352.2

59.9

469.9

490.6

301.0

499.2

527.0

.8

5.7

2.6

5.3

2.2

1.7

7.6

10.4

39.8

168.5

162.5

286.0

252.9

183.2

235.7

269.3

.5

3.8

6.7

10.0

5.8

7.2

16.6

8.8

43.9

59.7

1.5

51.9

104.4

10.8

67.0

592.3

--

2.6

1.3

6.3

11.1

2.6

9.1

149.5

Mid-1960s

Early 1980s

Early to mid- 1980s

Late 1980s

Early to mid- 1990s

1980

Late 1980s to early 1990s

Mid-1990s

'Data for wells 1 J-1 and 1J-2 originally were inconsistent with other measurements from this well nest; therefore, the data were switched, wl ; ch 

made them consistent with the other analytical results.

Analytical Resul - 29
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, w

1995 through 1999

[mo, month; d, day; yr, year; ICP, inductively coupled plasma; MS, mass spectrometry; fig/L, micrograms per liter; ES, environmental sample; LRS, laboratory re

uranium activity ratio; --, no data]

 n 

5'

a

a

3 

0«<"

o'

0_

<D

O

a

(A

0)

a

3

0_

o'

2L

33

(D

(A

£

5'

5

(D

o

O

 n

0

(A

>

(D

fi>

1V>

(S

T

z

(D

cr

(A

.p*

<c

<o

r

(O 

(O

Analytical methods and results 1

Sample

date

Map index number (mo/

(figs. 1 and 2) d/yr)

SWl 05/27/97

07/08/97

07/21/97

08/04/97

09/08/97

08/25/98

08/23/99

SW2 06/17/97

06/25/99

08/24/99

SW3 07/23/98

08/25/98

06/25/99

08/24/99

SW4 06/25/99

08/24/99

SW6 10/20/97

07/23/98

06/25/99

08/24/99

Time

(24

hour)

1345

1050

1140

1130

1145

0830

1700

1300

0830

1030

1100

1015

1115

1300

0700

0800

1300

1300

1015

1400

ICP/MS

old method

Uranium

concentrations

(ng/L)

ES LRS

9.0

7.0 8.6

6.6

6.3

7.4

7.3

7.9

9.8

10.3

13.0

11.7

12.8

10.6

13

14.5

22.3

43.4

26.5

17.4

24.8

ES

..

-

-

--

1.571

--

1.573

1.554

--

..

1.577

1.576

1.642

1.636

--

1.735

1.716

ICP/MS

new method

UAR

(234U/238U)

ME LRS ME

Surface-water samples

..

--

1.569 0.018

--

0.009

--

.009

.012

--

..

.005

.005

.005

.005

..

--

.007

.006 1 .743 .003

Alpha partic

Uranium concentrations

(H9/L)

ES ME LRS ME 

8.4 0.2 -- -- 

7.1 .2 -- -- 

6.7 .2 6.4 0.1 

6.0 .1 -- -- 

6.4 .1 -- -- 

7.1 .2 -- - 

9.1 .2 -- -- 

--

--

--

12.4 0.2 -- -- 

..

--

1 

..

-

--
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, w

1995 through 1999 Continued

Analytical Results

Sample 

date 

Map index number (mo/ 

(figs. 1 and 2) d/yr)

SW7 06/18/97

SW8 06/18/97

06/25/99

08/24/99

SW9 06/17/97

10/20/97

11/24/97

12/15/97

01/20/98

02/17/98

03/18/98

05/13/98

06/23/98

07/23/98

08/18/98

08/25/98

09/16/98

11/12/98 

06/25/99

07/23/99 

08/24/99

Time 

(24 

hour)

1000

0830

1045

1230

1445

1430

1100

1330

1500

1430

1330

1100

1120

1230

1530

1130

1030

1045 

1215

1230 

1700

ICP/MS

old method

Uranium 

concentrations 

(H9/L)

ES LRS

14.2 13.6,

13.0

15.9 17.4

16.0

17.6

11.0

27.8 28.1

30.8

29.7 30.2

30.0

31.1

15.4

16.2

17.3

19.4

23.3 23.4

20.7

20.9 20.9

30.0 

11.2

11.2 

21.7

Analytical methods and results1

ICP/MS

new method Alpha particl

UAR Uranium concentrations 

(234U/238U) (jig/L)

ES ME LRS ME ES ME LRS ME

Surface-water samples Continued

11.4 0.2 12.5 0.2

16.3 .2

1.876 0.006 1.874 0.003

1.853 .008

9.8 .2

1.640 .004

..

-

1.552 .005

..

--

1.706 .005

19.6 .2

1.703 .004

1.632 .004 

1.602 .004

1..688 .008

SW10 06/17/97 1530 11.4 11.8 11.1 
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, w

1995 through 1999 Continued

jjT Analytical methods and results1

I 

3

a

D>

o- Map index number 

£ (figs. 1 and 2)

8 swn

s

o

w 1A-1

D>

Q.

M

f 1A-2

3) 

(D

g 1A-3

w5'

(D

1 IB-1

3"

3

n»

(0

£ IB-2

8 

1C-1

1

Z

§" 1C-2

(0

S 1C-3

->

1C-4

Sample 

date 

(mo/ 

d/yr)

06/18/97

09/02/98

06/19/97

08/27/98

08/28/98

06/19/97

06/19/97

08/27/98

07/14/99

06/19/97

09/02/98

06/19/97

06/18/97

08/24/98

06/18/97

08/27/98

06/18/97

08/27/98

06/18/97

07/14/99

Time 

(24 

hour)

1100

0900

0920

0830

0930

0940

1000

0945

1105

1055

0905

1035

0705

1400

0725

1100

0745

1500

0815

1207

ICP/MS 

old method

Uranium 

concentrations

ES LRS

9.6 9.6

13.1

9.8 9.7

11.0

12.1

8.7

9.1

10.9

6.9

14.9

10.3

13.8

13.9

12.9

12.6

13.2

14.0

15.5

12.7

14.4

ICP/MS 

new method Alpha partic

UAR Uranium concentrations 

(234U/238U) (ng/L)

ES ME LRS ME ES

Surface-water samples Continued

9.6

12.1

Ground-water samples

9.3

10.6

11.6

8.1

8.9

10.3

14.7

9.6

14.0

12.5

13.0

11.8

12.9

12.8

14.6

11.8

ME LRS ME

0.2

.3

.1

.1

.2

.2

.1

.1

.2

.2

.2

.2

.2

.2

.2

.2

.2

.2

_
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, w

1995 through 1999 Continued

Map index number 

(figs. 1 and 2)

ID-1

ID-2

ID-3

IE-1

1E~2

Sample 

date 

(mo/ 

<Wr)

06/17/97

09/02/98

06/17/97

09/02/98

06/17/97

06/17/97

10/21/97

01/21/98

02/19/98

05/12/98

07/21/98

08/24/98

06/17/97

10/21/97

01/21/98

02/19/98

05/12/98

07/21/98

08/24/98

Time 

(24 

hour)

1310

1015

1325

1100

1345

0905

0820

0935

0910

0920

0910

1000

0925

0840

0955

0930

0935

0930

1100

ICP/MS 

old method

Uranium 

concentrations

(ng/L)

ES LRS

13.6 13.6

13.8

13.3 13.3,

13.2

14.5 16.8,

15.1

13.1

19.5

19.3

17.2

18.7

17.4

17.4

17.1

14.0

13.3

14.4

14.5

14.3

14.4 14.5

14.7 14.5

Analytical methods and results1

ICP/MS 

new method Alpha particl

UAR Uranium concentrations 

(234U/238U) (H9/L) 

ES ME LRS ME ES ME LRS ME 

Ground-water samples Continued

12.4 0.2 -- -- 

12.4 .3 -- -- 

9.5 .2 11.1 0.3 

14.7 .2 - -- 

11.3 .2 -- - 

16.9 .2 -- -- 

1.983 0.003

-

..

1.605 .006

_

--

12.8 .2 -- -- 

1.740 .004

-

-

-

13.2 .2 - - 
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, 

1995 through 1 999 Continued

m 

1

3

(D

a

o>

a.

3

«<£

o"

o>

1o

w"

fit

3

a

1

0

SL

3)

1

3

5

(D

O

§3-

a01

sr

~*

S

!(0

Z

&

Sample

date

Map index number (mo/

(figs. 1 and 2) d/yr)

IE-3 06/17/97

10/21/97

01/21/98

02/19/98

05/12/98

07/21/98

08/24/98

07/14/99

1F-1 06/16/97

10/21/97

01/21/98

02/18/98

05/12/98

07/21/98

09/01/98

1G-1 06/17/97

10/21/97

m /i i /as

Time

(24

hour)

0940

0900

1010

0950

0950

0945

1215

1315

1555

0935

1040

1445

1015

1015

1600

0800

1005

i ttn

ICP/MS

old method

Uranium

concentrations

(H9/L)

ES LRS

4.0 4.0

4.4

5.5

4.9

3.9

4.0

3.8

3.7

10.7

5.6

11.5

13.6

13.8

9.8

8.6 8.6

12.2

12.1

11 n

Analytical methods and results1

ICP/MS

new method Alpha parti

UAR Uranium concentrations 

(234U/238U) (^g/L) 

ES ME LRS ME ES ME LRS ME 

Ground-water samples Continued

3.6 0.1 -- -- 

1.461 0.006 1.423 0.024

--

1.438 .014 3.9 .1 -- - 

--

10.3 .3 -- - 

--

*

..

..

1.456 .005 7.9 .2 -- - 

11.0 .2 - -- 

1.621 .004

02/18/98 1330 12.2 

04/27/98 1245 11.4

07/21/98 

08/27/98

1105

1515

11.6

11.5 11.5

1.526

11.2 
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, w

1995 through 1999 Continued

Analytical methods and results1

ICP/MS 

old method

ICP/MS 

new method Alpha particle 

Map index number 

(figs. 1 and 2)

Sample 

date 

(mo/ 

d/yr)

Time

(24

hour)

Uranium

concentrations

(H9/L)

UAR

(234U/238U)

Uranium concentrations 

(H9/L)

ES LRS ES ME LRS ME ES ME LRS ME 

1G-2 06/17/97 0820 12.5

10/21/97 1025 13.2

01/21/98 1145 13.0

02/18/98 1350 12.8

04/27/98 1305 12.4

13.2

Ground-water samples Continued

11.5 0.2 

07/21/98 1140 11.9 1.647 0.007

1G-3 06/17/97 0840 12.5

10/21/97 1045 12.2

01/21/98 1205 12.7

02/18/98 1410 12.7

04/27/98 1320 12.3 12.3

10.6 .2 

07/21/98 1125 12.3

08/27/98 1600 12.1

07/14/99 1345 11.2

1.583 .006

11.6 .1 

>

1H-1 06/16/97 1330 15.3

10/20/97 1225 14.7

01/20/98 1305 17.8

04/28/98 1040 15.0

07/20/98 1050 14.2

16.0

1.884 .004

13.6 .2 

o

SL

30 

(0m

09/01/98 1230 14.0 13.4 .2 
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, 

1995 through 1999 Continued

_

I n

5' 

a

01

a

SL

o'

SL

3

s

o

a

01

a

3

SL

o'

SL

30

g

M

5'

g:

(D

O

O

 n

01

3

I

 t

3

Z

(D

3

(0

01

'3

Sample

date

Map index number (mo/

(figs. 1 and 2) d/yr)

1H-2 06/16/97

10/20/97

01/20/98

04/28/98

07/20/98

09/01/98

1H-3 06/16/97

10/20/97

01/20/98

04/28/98

07/20/98

11-1 06/16/97

10/22/97

01/20/98

04/28/98

07/21/98

08/28/98

11-2 06/16/97

10/22/97

01/20/98

04/28/98

07/21/98

Time

(24

hour)

1350

1245

1320

1055

1105

1315

1405

1300

1335

1110

1125

1435

1320

1400

1350

1310

1100

1450

1335

1400

1405

1345

ICP/MS

old method

Uranium

concentrations

(ng/L)

ES LRS

20.9

22.7 22.6

21.2 21.2

21.7

22.6

21.2

14.4

6.4 6.4

12.5 12.5

13.0

17.0

19.3 19.3

22.3

24.8

24.9

21.5

24.9

22.5

22.7

21.4

22.0 22.1

22.4

Analytical methods and results1

ICP/MS

new method Alpha parti

UAR Uranium concentrations 

(234^238^ ^g/g 

ES ME LRS ME ES ME LRS ME 

Ground-water samples Continued

20.8 0.3 - -- 

1.781 0.004

~

20.8 .3 -- - 

13.5 .3 -- - 

1.608 .007

_

..

-

17.4 .2 -- -- 

1.758 .004

..

-.

1.728 .006 1.727 0.007

24.6 .3 « -- 

22.2 .4 -- - 

1.749 .012

-

-

1.727 .007
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, we

1995 through 1999 Continued

Map index number 

(figs. 1 and 2)

11-3

U-l

1J-2

Sample 

date 

(mo/ 

d/yr)

06/16/97

10/22/97

01/20/98

04/28/98

07/21/98

08/28/98

06/16/97

10/22/97

01/20/98

02/17/98

04/27/98

07/20/98

09/01/98

11/12/98

06/16/97

10/22/97

01/20/98

02/17/98

04/27/98

07/20/98

09/01/98

11/12/98

Time 

(24 

hour)

1510

1350

1430

1420

1405

1145

1140

1010

1135

1430

1405

1200

0820

1245

1200

1025

1150

1450

1425

1215

0930

1315

ICP/MS 

old method

Uranium 

concentrations

ES LRS

27.0 26.9

27.4

24.0

31.3

27.4

26.2

18.6

20.3

20.2

20.4

19.6

19.9 19.9

19.7 19.6

-

14.2

16.1

16.9 16.9

19.4

15.7

16.1

16.3

-

Analytical methods and results1

ICP/MS 

new method Alpha particle 

UAR Uranium concentrations 

(234^238^ fag/L) 

ES ME LRS ME ES ME LRS ME 

Ground-water samples Continued

24.7 0.3 - -- 

1.712 0.004

..

--

23.2 .2 -- - 

17.8 .2 - -- 

1.628 .004

..

..

--

19.6 .3 -- - 

18.9 .3 -- -- 

13.4 .2 - -- 

1.760 .004

-

-

--

_

15.3 .2 -- - 

15.0 .2 - - 
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, w

1995 through 1999 Continued

2.

5

 n

5'

a

PI

I

s0)

1

g

as

o

§ 

B>

g.

5L

0

2L

30

5"

1<p 

O

1

 n

i

3

5

1

z

I

w

»

i

£***

Sample

date

Map index number (mo/

(figs. 1 and 2) d/yr)

U-3 06/16/97

10/22/97

01/20/98

02/17/98

04/27/98

07/20/98

09/01/98

11/12/98

07/14/99

IK-1 06/16/97

10/22/97

04/28/98

IK 07/20/98

(blank) 07/20/98

(field duplicate) 07/20/98

IK-2 06/16/97

10/22/97

04/28/98

07/20/98

IK-3 06/16/97

10/22/97

Time

(24

hour)

1220

1045

1205

1510

1445

1235

1015

1345

1443

0920

1500

0935

1305

1300

1310

0935

1515

0950

1325

0955

1530

ICP/MS

old method

Uranium

concentrations

(H9/L)

ES LRS

20.8

21.3

20.1

18.8 18.8

16.4

15.0

15.4

12.8

13.5

21.0

18.7

18.8

19.2

0 .1

19.4

21.7 21.7

21.7

20.6

21.7

17.8

26.4 26.4

Analytical methods and results1

ICP/MS

new method Alpha particl

UAR Uranium concentrations 

(234U/238U) (ng/L) 

ES ME LRS ME ES ME LRS ME 

Ground-water samples Continued

19.2 0.3 -- - 

1.628 0.004

..

..

14.4 .2 -- - 

12.8 .2 - -- 

-

20.2 .3 - -- 

-

-

-

20.6 .3 -- - 

1.743 .005

-

-

17.6 .2 - -- 

04/28/98 1005 25.7 

07/20/98 1640 27.0
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, w

1995 through 1999 Continued

Sample 

date 

Map index number (mo/ 

(figs. 1 and 2) d/yr)

Time 

(24 

hour)

ICP/MS 

old method

Uranium 

concentrations

ES LRS

Analytical methods and results1

ICP/MS 

new method Alpha particl

ES

UAR Uranium concentrations

(234U/238U) ^g/L)

ME LRS ME ES ME LRS ME

Ground-water samples Continued

J>

SL

o"

Si.

3

i

1L-1 06/16/97

10/22/97

01/20/98

02/17/98

04/27/98

07/22/98

08/25/98

1L-2 06/16/97

10/22/97

01/20/98

02/17/98

04/27/98

07/22/98

08/25/98

1L-3 06/16/97

10/22/97

01/20/98

02/17/98

04/27/98

07/22/98 

08/25/98

07/15/99

0810

0855

0945

1020

1000

0945

1230

0825

0910

1000

1040

1015

1005

1330

0845

0930

1015

1100

1035

1025 

1400

1020

17.0

19.4

19.7

17.1

30.1

34.8 34.8

17.5 17.5

16.4

16.2

17.6 17.5

17.5

15.8 15.8

16.0

15.6

31.9

32.5

32.9

34.0 34.0

17.9

17.9 

35.1

34.7

--

1.644

-

--

1.566

1.559

1.567

1.570

--

-

-

1.586

-

..

1.553

-

--

1.624

1.621 

1.558

-

17.2 0.2 16.8 0.2

0.002

-.

.004

.004

.on

15.3 .2

.004

..

..

-

.007

--

29.6 .3

.003

..

-.

.005

.004 

.003

-
£

Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, 

1999 -Continued

o i : 

<? Analytical methods and results 1

 n

0

a

n>

a.

g Map index number 

 5 (figs. 1 and 2)

o

SL

S 1M-1

«

J

(0

3 1M-2

Q.

>

SL

p 1M-3 

SL

30

8

c_ 

» 1N-1

3

| 2A-1

13- 

 n

S

£ 2B-1

 

I

Z

!

~_i

Pto'3

Sample 

date 

(mo/ 

d/yr)

06/17/97

08/31/98

06/17/97

08/31/98

06/17/97

08/31/98

06/18/97

06/18/97

08/26/98

07/14/99

04/21/97

04/28/97 

05/12/97

05/27/97

06/09/97

06/19/97

06/23/97

07/08/97

07/21/97

08/04/97

Time 

(24 

hour)

1525

0830

1545

1000

1605

1040

1555

1525

1230

955

0925

1115 

1415

1505

1345

0720

1340

1305

1435

1355

ICP/MS 

old method

Uranium 

concentrations

ES LRS

17.2

16.8

15.9 15.8

18.0 18.0

12.8

11.0

14.5

11.1

13.2 13.2

10.7

9.9

9.9 

9.8 9.4

10.1

10.5

10.2 10.2

9.7

9.1

11.1

10.1

ICP/MS new method Alpha particl

UAR Uranium concentrations

(234y/238y) (jig/L)

ES ME LRS ME ES

Ground-water samples Continued

15.7

-

14.3

..

11.8

1.290 0.004

13.9

10.4

--

..

9.0

2.096 0.021 8.1 

8.5

2.092 .014 8.8

9.7

10.0

9.2

8.9

10.8

9.7

ME LRS ME

0.2

-

.2

..

.2

-

.2

.2

--

.2

.1 

.1

.1

.1

.1

.1

.1

.1

.2

09/08/97 1430 10.8 9.3 
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, we

1999 Continued

at

 5

Analytical methods and results1

Map index number 

(figs. 1 and 2)

2B-1

2B-2

2B-3

Sample 

date 

(mo/ 

d/yr)

09/30/97

08/26/98

04/21/97

04/28/97

05/12/97

05/27/97

06/09/97

06/19/97

06/23/97

07/08/97

07/21/97

08/04/97

09/08/97

09/30/97

08/26/98

04/21/97

04/28/97

05/12/97

05/27/97

06/09/97

06/19/97

06/23/97

07/08/97

07/21/97

Time 

(24 

hour)

0905

1400

0940

1140

1435

1525

1405

0740

1400

1325

1455

1415

1445

0925

1430

1000

1200

1455

1545

1425

0800

1420

1 345

1515

ICP/MS 

old method

Uranium 

concentrations 

(H9/L)

ES LRS

9.9 10.1

10.5

10.1

10.2

10.2

13.7 12.9

11.0 10.9

9.7

10.3

13.0 13.0

12.4 12.4

9.9 9.9

8.3

7.0

8.7

11.4 11.4

10.6

12.1

11.6 11.6

9.3 9.3

10.1

10.4

1 1.8

11.2

ICP/MS new method Alpha particle 

UAR Uranium concentrations

(234^238^ ^^

ES ME LRS ME ES

Ground-water samples Continued

9.3

-

9.1

9.1

9.5

12.1

9.3

9.8

10.0

12.9

12.2

9.9

7.2

6.3

1.617 0.004

10.0

10.3

11.3

10.3

9.3

9.9

10.2

10.5

11.6

ME LRS ME

0.2

-

.2

.2

.2

.2

.2

.2

.1

.2

.2

.1

.1

.2

--

.2

.3

.2

.2

.2

.1

.1

.1

.2
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, w

1999 Continued

m_ 

 n

(D*

a

£ Map index number 

3 (figs. 1 and 2)

 £

8 2B-3

i

0

w*

sa

H 2C-1

2 

£L

j? 2C-2

c_

?. 2C-3

3

| 2D-1 

| 

3

§ 2D-2

I

8 2D-3

i

!

Sample 

date 

(mo/ 

d/yr)

08/04/97

09/08/97 

09/30/97

08/26/98

07/14/99

06/19/97

06/19/97

06/19/97

06/18/97 

08/27/98

06/18/97

08/27/98

06/18/97

08/27/98

07/14/99

Time 

(24 

hour)

1435

1505 

0945

1545

1030

0825

0845

0905

0840 

1215

0900

1300

0920

1400

1140

ICP/MS 

old method

Uranium 

concentrations

ES LRS

8.5

7.3 

6.9

7.1 7.1

12.2

11.1

10.8

10.0

13.0 

13.5

19.2

23.3

14.0

16.3

15.8

Analytical methods and results1

ICP/MS new method Alpha particle 

UAR Uranium concentrations

(234U/238U) ^g/g

ES ME LRS ME ES ME LRS ME

Ground-water samples Continued

8.3 0.1

6.8 .1 

6.8 .2

1.554 0.04

--

10.4 .1

10.6 .1

9.8 .1

12.9 .2

18.5 .2

--

14.9 .3

..

2E-1 06/18/97 1450 14.9 

08/26/98 1100 14.9

14.4 

2F-1

2F-2

06/17/97 1005 19.9

06/17/97 1025 16.4

16.0

15.0

.2 18.0 .2 
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, w

1999 Continued

SL

I

0)

I

Map index number 

(figs. 1 and 2)

2F-3

2G-1

2H-1

2H-2

Sample 

date 

(mo/ 

d/yr)

06/17/97

07/14/99

06/16/97

10/22/97

01/21/98

02/18/98

05/12/98

07/21/98

06/17/97

10/21/97

01/20/98

02/18/98

05/12/98

07/21/98

09/01/98

06/17/97

10/21/97

01/20/98

02/18/98

05/12/98

07/21/98

09/01/98

Time 

(24 

hour)

1045

1245

1540

1115

1105

1255

1045

1040

0715

1115

1455

1055

1115

1220

1420

0730

1135

1510

1130

1135

1240

1440

ICP/MS

old method

Uranium 

concentrations 

(H9/L)

ES LRS

3.6

2.0

9.2

10.8

8.5

10.0

8.8 8.8

8.4

15.3

12.3

12.9

13.7

13.1

13.3

12.9

17.1 17.2,

16.4

17.4

15.5

15.1 15.1

14.7

14.1

14.1

Analytical methods and results1

ICP/MS new method Alpha particle 

UAR Uranium concentrations 

(234U/238U) (Mg/L) 

ES ME LRS ME ES ME LRS ME 

Ground-water samples Continued

3.5 0.2 - -- 

1.316 0.011

8.8 .2 -- -- 

1.505 .004

-

-

15.2 .2 -- -- 

..

..

--

13.0 .3 - -- 

15.3 .2 - - 

1.596 .004 1.600 0.015

-

..

-

_

13.0 .2 - -- 
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, 

1999 Continued

(D

a

J Fieldand Analyti

o 

2L

JD

f

w

01

a

3

01

Io 

SL

3J

(D W

c

5T

5'

s

(D

D

1 n

1

3

$

(0

Nebraska, 1

?'2

Sample 

date 

Map index number (mo/ 

(figs. 1 and 2) d/yr)

2H-2 07/14/99

2J-1 06/16/97

10/22/97

01/20/98

04/27/98

07/20/98

08/31/98

2J-2 06/16/97

10/22/97 

01/20/98

04/27/98

07/20/98

08/31/98

2J-3 06/16/97

10/22/97

01/20/98 

04/27/98 

07/20/98

08/31/98

07/14/99

2L-1 06/16/97

09/02/98

Time 

(24 

hour)

1415

1030

1415

1045

1110

1415

1215

1055

1430 

1100

1125

1430

1300

1115

1445

1115 

1140 

1445

1345

1510

0705

1230

ICP/MS

old method

Uranium 

concentrations

ES LRS

13.6

14.8

20.3

19.5

21.8

22.6

22.6

16.7

18.9 

19.2

19.0 19.0

18.7

17.6 17.7

14.2

15.3

16.9 16.9 

13.9 14.0 

14.9

14.4

16.1

16.4

16.4

Analytical methods and results1

ICP/MS new method Alpha particl

UAR Uranium concentrations 

(234yy238y\ (|Jig/L) 

ES ME LRS ME ES ME LRS ME 

Ground-water samples Continued

..

12.1 0.2 14.1 0.2 

1.850 0.003

-

-

-

14.4 .2 -- -- 

:: : :: :: ;: :: :: :: 

..

--

13.6 .3 -- - 

1.599 .004

-

--

16.5 .3 -- -- 

15.3 .2 -- - 
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, we

1999 Continued

Analytical methods and results1

ICP/MS 

old method ICP/MS new method Alpha particle 

Sample Uranium

date Time concentrations 

Map index number (mo/ (24 

(figs. 1 and 2)

UAR

(234u/238y)

Uranium concentrations 

d/yr) hour) ES LRS ES ME LRS ME ES ME LRS ME 

21^2 06/16/97 0725 14.9 

09/02/98 1250 16.7

14.9

Ground-water samples Continued

14.1 0.3 

15.5 .2

21^3 06/16/97 0740 29.9 

07/14/99 1603 24.8

26.9 

2T-1 

3B-1

07/13/99 0930 11.3

06/18/97 1320 10.5

07/08/99 1537 11.0

2.013 0.005

10.7 .1 

3B-2 06/18/97 1340 12.6 

07/08/99 1600 10.9

12.3 .2 

3C-1 06/18/97 0950 14.1 

07/12/99 0955 13.8

14.4 .2 

3C-2 06/18/97 1010 12.1 

07/12/99 1015 12.5

12.1 11.6 .2 

3C-3 06/18/97 1030 11.1 

07/12/99 1035 12.8

11.2 .2 11.1 0.1 

3E-' 06/17/97 1415 19.9 

07/08/99 1335 20.3

18.9 .2 

3E-2 06/17/97 1345 13.5 13.5 

07/08/99 1400 13.1

12.2 .2 
$ 

I

i Fieldand Analytical

1

W

at

a

1

1

fw

3

the Dutch

 n

i

32

I

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?r 

S

?

<o

Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, 

1999 Continued

Analytical methods and results1

ICP/MS

, w

old method ICP/MS new method Alpha particle 

Map index number 

(figs. 1 and 2)

3E-3

3F-1

3F-2

3F-3

4A-1

4B-1

4B-2

4B-3

5B-1

5B-2

5B-3

5C-1

5C-2

Sample 

date 

(mo/ 

d/yr)

06/17/97

07/08/99

06/17/97

07/08/99

06/17/97

07/08/99

06/17/97

07/08/99

06/18/97 

07/08/99

06/18/97

07/12/99

06/18/97 

07/12/99

06/18/97

07/12/99

06/19/97

06/19/97

06/19/97

07/07/99

07/07/99

Time 

(24 

hour)

1455

1425

1110

1128

1130

1155

1150

1215

1405 

1503

1100

1125

1120 

1145

1140

1205

1130

1200

1220

1025

1050

Uranium 

concentrations UAR Uranium concentrations 

(ng/L) <234u/238U) (ng/L)

ES LRS ES ME LRS ME ES ME LRS ME

Ground-water samples Continued

10.4 - -- -- -- - 9.4 0.2

8.7

16.8 -- -- - -- -- 15.5 .3

10.7

16.4 16.4 - - -- - 15.6 .2

7.8

11.4 11.4 -- - -- -- 10.1 .2

8.5

12.6 -- -- - -- - 12.0 .2 

12.9

12.6 -- -- -- -- -- 11.8 .2

13.4

9.2 9.3 -- -- -- - 8.7 .1 

10.1

8.4 -- 1.521 0.003 -- - 8.7 .2

9.3

14.2 -- -- -- - - 14.0 .2

13.1 - -- - - -- 12.7 .2

11.8 -- -- -- -- -- 11.2 .1

15.5

14.7
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, we

1999 Continued

Analytical methods and results1

ICP/MS

old method ICP/MS new method Alpha particle 

Analytical

31 

(D 

(0

Map index number 

(figs. 1 and 2)

5D

5E-1

5E-2

5F

6A

6B

6C

6D-1

6D-2

6E

6F

6G-1

6G-2

6H-1 

6H-2

61

Sample 

date 

(mo/ 

d/yr)

07/07/99

07/07/99

07/07/99

07/01/99

06/28/99

06/28/99

06/28/99

06/29/99

06/29/99

06/28/99

06/30/99

06/30/99

06/30/99

06/30/99 

06/30/99

06/30/99

Time 

(24 

hour)

1117

1310

1335

1455

1145

1405

1452

1015

1037

1613

1425

1130

1150

1240 

1305

0945

Uranium 

concentrations UAR Uranium concentrations

(|xg/L) (23^/238^ (|xg/L)

ES LRS ES ME LRS ME ES ME LRS ME

Ground-water samples Continued

14.7

33.1

41

33.7

19.8

19.8

20.1

16

12.6

8.7

10.5

34.7

20.4

24.7 

42.4

70.6

08/26/98 0830 55.5 55.2, 

54.7

1.511 0.002 49.1 0.6 
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, w

1999 Continued

ID 

|

i Fieldand Analyti

8

I

o 

a w

0

a

SL

0_

3J

c_

a

*+

he DutchF

§

3

0

1

1

Nebraska,

to

1

Map index number 

(figs. 1 and 2)

6M-1

6M-2

7A-1

7A-2

7B

7C-1

7C-2

7D-1 

7D-2

7B-1

7E^2

7F-1

7F-2

7G-1 

7G-2

7H

8A-1

8A-2

Sample 

date 

(mo/ 

d/yr)

06/30/99

06/30/99

06/28/99

08/23/99

06/28/99

06/28/99

06/29/99

06/29/99

06/29/99 

06/29/99

06/29/99

06/29/99

07/01/99

07/01/99

06/30/99 

06/30/99

07/01/99

06/29/99

06/29/99

Time 

(24 

hour)

1030

1053

1255

1015

1315

1530

1115

1142

1435 

1515

1555

1625

1125

1155

1503 

1525

0945

1255

1315

ICP/MS

old method

Uranium 

concentrations

ES LRS

18.6

40.7

13.8

12.9

22.9

18.8

12.5

8.2

18.9 

17.6

28.8

9.9

30.6

29.1

33.4 

7.8

60.6

12.3

9.3

Analytical methods and results1

ICP/MS new method Alpha particl

ES

--

1.740

2.334

2.015

--

-

1.259

1.730

1.371

1.626

1.550

1.614 

1.000

1.973

..

..

UAR Uranium concentrations 

(234^238^ (lig/L)

ME LRS ME ES ME LRS ME

Ground-water samples Continued

--

0.005

.008

.006

..

..

.on

.009

.009

.004

-

.005 

.015

.007
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, we

1999 Continued

Analytical methods and results1

ICP/MS

old method ICP/MS new method Alpha particle 

Analytical

Results

Map index number 

(figs. 1 and 2)

8B

8C

8D-1

8D-2

8E

8F-1

8F-2

8G

9B

9C

9D-1

9D-2

9E-1

9E-2

10A-1 

10A-2

10C

Sample 

date 

(mo/ 

d/yr)

06/29/99

07/08/99

07/08/99

07/08/99

06/30/99

07/01/99

07/01/99

07/01/99

07/07/99

07/07/99

07/07/99

07/07/99

07/01/99

07/01/99

07/06/99 

07/06/99

07/07/99

Time 

(24 

hour)

1355

1050

0940

1005

1600

1025

1050

1250

1525

1555

1420

1445

1345

1415

1415 

1444

0942

Uranium 

concentrations UAR Uranium concentrations

fag/L) (234U/238U) (^g/L)

ES LRS ES ME LRS ME ES ME LRS ME

Ground-water samples Continued

14.3

2.9

23.7

29.7

12.0

73.0 - 1.915 0.003

45.1

27.1 -- 1.586 .003

15.9

11.6

31.2

34.1

88.8 - 1.324 .002

79.7 - 1.332 .004 1.325 0.002

17.5 

9.1 -- 1.558 .009

7.6

10D-1 07/06/99 1300 20.0 1.686 .006
§

#2.

I

Tl 5' 

a

o>

a

SL

3' 

SL

5

1

w

3

a

S

SL

3'

SL

3D

MI

c

5f

5"

5

a

c5*

&

Tl

£

W

I

1

1

z

8

JU

(O

(O

V

Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, 

1999 Continued

Map index number

(figs. 1 and 2)

10D-2

10B-1

10B-2

10G-1

10G-2

10K-1

10M-1

10M-2

IK-94-1

IK-94-2

26K-94-1

Sample

date

(mo/

d/yr)

07/06/99

07/01/99

07/01/99

07/06/99

07/06/99

07/13/99

07/06/99

07/06/99

10/23/97

07/22/98

08/25/98

09/14/99

10/23/97

07/22/98

09/14/99

01/21/98

07/22/98

09/01/98

Time

(24

hour)

1323

1525

1545

1125

1150

1230

1555

1615

0755

1215

1530

1120

0815

1225

1150

1320

1110

1130

ICP/MS 

old method

Uranium

concentrations

(ng/L)

ES LRS

20.1

31.2

30.9

23.3

30.8

17.8

13.4

12.7

6.5

12.5

1.4

-

74.4

88.3

--

24.5

24.9

22.4

Analytical methods and results1

, w

ICP/MS new method Alpha particle 

ES

1.660

1.776

1.680

-

1.775

2.156

1.548

..

1.496

2.131

1.494

..

1.441

1.441

1.647

1.574

UAR Uranium concentrations

(234U/238U) (j|g/L)

ME LRS ME ES ME LRS ME

Ground-water samples Continued

0.012

.005

.007

..

.010

.007 2.137 0.002

_

.008

6.6

.012 -- - 12.5

.006 -- - 1.5 0.1

.005 1.493 .005

68.0

.007

.004

.007 1.385 .012

.007

26K-94-2 01/21/98 1305 20.7

01/21/98 1350 64.3

07/22/98 1130 23.6
Table 7. Uranium concentrations and activity ratios in surface-water, ground-water, and well-cutting samples, Dutch Flats area, we

1999 Continued

Analytical methods and results1

ICP/MS 

old method

Sample Uranium 

date Time concentrations 

Map index number (mo/ (24 MM

(figs. 1 and 2) d/yr) hour) ES LRS

26K-94-3 01/21/98 1410 66.5

C. Morrill 08/31/98 1530 .1 

Brule Ash first leach

Brule Ash second 

leach

Volcanic ash

2B-1 at 95 feet

2E-lat75feet

61 at 30 feet

IK-94-1 at 30 feet

ICP/MS new method Alpha particle 

UAR Uranium concentrations 

(234^238^ (|Lig/L) 

ES ME LRS ME ES ME LRS ME 

Ground-water samples Continued

0.3 0.1 -- - 

Samples from well cuttings2

1.668 0.007

1.638 .006

.986 .002

1.642 .004

1.326 .003

1.509 .005

1.858 .003

Numbers in bold represent analyses repeated on different days. 

2Samples from well cuttings were collected when wells were constructed between 1995 and 1999.
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*U.S. GPO Z001 -0-657-386