Quality and Sources of Ground Water

used for Public Supply in Salt Lake

Valley, Salt Lake County, Utah, 2001

Water-Resources Investigations Report 03–4325

U.S. Department of the Interior

U.S. Geological Survey

National Water-Quality Assessment Program
U.S. GEOLOGICAL SURVEY

Quality and Sources of Ground Water Used for 

Public Supply in Salt Lake Valley, Salt Lake County, 

Utah, 2001

NATIONAL WATER-QUALITY ASSESSMENT PROGRAM

By Susan A. Thiros and Andrew H. Manning

Salt Lake City, Utah

2004

Water-Resources Investigations Report 03-4325
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

For additional information write to:

District Chief

U.S. Geological Survey

2329 West Orton Circle

Salt Lake City, Utah 84119

Copies of this report can be purchased from:

U.S. Geological Survey

Branch of Information Services

Box 25286

Denver Federal Center

Denver, Colorado 80225-0286

1-888-ASK-USGS

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. 

Government.

District Chief

U.S. Geological Survey

2329 West Orton Circle

Salt Lake City, Utah 84119

http://ut.water.usgs.gov
iii

FOREWORD

The U.S. Geological Survey (USGS) is committed to serve the Nation with accurate and timely scientific 

information that helps enhance and protect the overall quality of life, and facilitates effective management of 

water, biological, energy, and mineral resources (http://www.usgs.gov/). Information on the quality of the 

Nation’s water resources is of critical interest to the USGS because it is so integrally linked to the long-term 

availability of water that is clean and safe for drinking and recreation and that is suitable for industry, irrigation, 

and habitat for fish and wildlife. Escalating population growth and increasing demands for the multiple water 

uses make water availability, now measured in terms of quantity and quality, even more critical to the long-term 

sustainability of our communities and ecosystems.

The USGS implemented the National Water-Quality Assessment (NAWQA) program to support national, 

regional, and local information needs and decisions related to water-quality management and policy (http://

water.usgs.gov/nawqa). Shaped by and coordinated with ongoing efforts of other Federal, State, and local 

agencies, the NAWQA program is designed to answer: What is the condition of our Nation’s streams and ground 

water? How are the conditions changing over time? How do natural features and human activities affect the 

quality of streams and ground water, and where are those effects most pronounced? By combining information 

on water chemistry, physical characteristics, stream habitat, and aquatic life, the NAWQA program aims to 

provide science-based insights for current and emerging water issues and priorities. NAWQA results can 

contribute to informed decisions that result in practical and effective water-resource management and strategies 

that protect and restore water quality.

Since 1991, the NAWQA program has implemented interdisciplinary assessments in more than 50 of the 

Nation’s most important river basins and aquifers, referred to as Study Units (http://water.usgs.gov/nawqa/ 

nawqamap.html). Collectively, these Study Units account for more than 60 percent of the overall water use and 

population served by public water supply, and are representative of the Nation’s major hydrologic landscapes, 

priority ecological resources, and agricultural, urban, and natural sources of contamination. 

Each assessment is guided by a nationally consistent study design and methods of sampling and analysis. 

The assessments thereby build local knowledge about water-quality issues and trends in a particular stream or 

aquifer while providing an understanding of how and why water quality varies regionally and nationally. The 

consistent, multi-scale approach helps to determine if certain types of water-quality issues are isolated or 

pervasive, and allows direct comparisons of how human activities and natural processes affect water quality and 

ecological health in the Nation’s diverse geographic and environmental settings. Comprehensive assessments on 

pesticides, nutrients, volatile organic compounds, trace metals, and aquatic ecology are developed at the national 

scale through comparative analysis of the Study-Unit findings (http://water.usgs.gov/nawqa/natsyn.html). 

The USGS places high value on the communication and dissemination of credible, timely, and relevant 

science so that the most recent and available knowledge about water resources can be applied in management 

and policy decisions. We hope this NAWQA publication will provide you the needed insights and information to 

meet your needs, and thereby foster increased awareness and involvement in the protection and restoration of our 

Nation’s waters. 

The NAWQA program recognizes that a national assessment by a single program cannot address all waterresource issues of interest. External coordination at all levels is critical for a fully integrated understanding of 

watersheds and for cost-effective management, regulation, and conservation of our Nation’s water resources. The 

program, therefore, depends extensively on the advice, cooperation, and information from other Federal, State, 

interstate, Tribal, and local agencies, non-government organizations, industry, academia, and other stakeholder 

groups. The assistance and suggestions of all are greatly appreciated.

Robert M. Hirsch

Associate Director for Water
iv
 v

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

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

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

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

Land and Water Use........................................................................................................................... 4

Ground-Water Hydrology .................................................................................................................. 4

Acknowledgments....................................................................................................................................... 7

Study Design and Methods .................................................................................................................................. 7

Site Selection............................................................................................................................................... 7

Sample Collection ....................................................................................................................................... 8

Sample Analysis.......................................................................................................................................... 12

Quality Assurance ....................................................................................................................................... 13

Ground-Water Quality.......................................................................................................................................... 14

Physical Properties...................................................................................................................................... 17

Major Ions ................................................................................................................................................... 18

Trace Elements............................................................................................................................................ 22

Nutrient Constituents and Dissolved Organic Carbon................................................................................ 24

Pesticides..................................................................................................................................................... 24

Volatile Organic Compounds...................................................................................................................... 29

Sources of Ground-Water Recharge .................................................................................................................... 34

Stable Isotopes ............................................................................................................................................ 34

Dissolved Gas Recharge Temperatures ...................................................................................................... 40

Tritium and Tritium/Helium-3 Ages........................................................................................................... 49

Chlorofluorocarbon Ages............................................................................................................................ 58

Relation Between Ground-Water Quality and Sources of Recharge ................................................................... 63

Summary .............................................................................................................................................................. 68

References Cited .................................................................................................................................................. 69

Appendix .............................................................................................................................................................. 82

CONTENTS
vi

Figure 1. Map showing location and geographic features of Salt Lake Valley, Utah....................................... 3

Figure 2. Map showing land use in Salt Lake Valley, Utah, 1994.................................................................... 5

Figure 3. Map showing average ground-water withdrawals from public-supply wells in Salt Lake 

Valley, Utah, 1996-99........................................................................................................................ 6

Figure 4. Generalized block diagram showing the basin-fill deposits and ground-water flow system in 

Salt Lake Valley, Utah....................................................................................................................... 8

Figure 5. Map showing location of ground-water recharge and discharge areas and 31 sampled publicsupply wells, and approximate direction of horizontal ground-water flow in Salt Lake Valley, 

Utah, 2001.......................................................................................................................................... 9

Figure 6. Map showing major-ion composition of water sampled from 31 public-supply wells in Salt 

Lake Valley, Utah, 2001 .................................................................................................................... 19

Figure 7. Map showing dissolved-solids concentration in water sampled from the principal aquifer in 

Salt Lake Valley, Utah, 1988-92. ...................................................................................................... 20

Figure 8. Map showing dissolved-solids concentration in water sampled from the principal aquifer in 

Salt Lake Valley, Utah, 1998-2002 ................................................................................................... 21

Figure 9. Map showing arsenic concentration in water sampled from the principal aquifer in Salt Lake 

Valley, Utah. ...................................................................................................................................... 23

Figure 10. Map showing radon concentration in water sampled from the principal aquifer in Salt Lake 

Valley, Utah, 1998-2001.................................................................................................................... 25

Figure 11. Map showing nitrate concentration in water sampled from the principal aquifer in Salt Lake 

Valley, Utah, 1998-2001.................................................................................................................... 26

Figure 12. Graph showing concentration of selected pesticides in water sampled from 31 public-supply 

wells in Salt Lake Valley, Utah, 2001 ............................................................................................... 27

Figure 13. Map showing total concentration of atrazine and its degradation products in water sampled 

from the principal aquifer in Salt Lake Valley, Utah, 1998-2001. .................................................... 30

Figure 14. Graph showing concentration of selected volatile organic compounds in water sampled from 

31 public-supply wells in Salt Lake Valley, Utah, 2001 ................................................................... 31

Figure 15. Map showing chloroform concentration in water sampled from the principal aquifer in Salt 

Lake Valley, Utah, 1998-2001........................................................................................................... 33

Figure 16. Map showing wells with delta oxygen-18, dissolved-gas, recharge-temperature, and (or) 

tritium/helium-3 age data for water sampled from the principal aquifer in Salt Lake Valley, 

Utah, 1990-2001 ................................................................................................................................ 35

Figure 17. Map showing delta oxygen-18 values for water sampled from the principal aquifer in Salt 

Lake Valley, Utah, 1990-2001 .......................................................................................................... 38

Figure 18. Map showing distribution of minimum mountain-front recharge fractions for water sampled 

from the principal aquifer in Salt Lake Valley, Utah, 1990-2001. .................................................... 39

Figure 19. Map showing distribution of maximum recharge temperatures for water sampled from the 

principal aquifer on the east side of Salt Lake Valley, Utah, 2000 ................................................... 41

Figure 20. Map showing distribution of minimum mountain-block recharge fractions for water sampled 

from the principal aquifer on the east side of Salt Lake Valley, Utah, 2000..................................... 46

Figure 21. Graph showing Tritium concentration in precipitation and the relation between initial tritium

concentration and apparent recharge year for water sampled from the principal aquifer in 

Salt Lake Valley, Utah, 2000-01 ...................................................................................................... 53

FIGURES
Figures vii

Figure 22. Map showing distribution of apparent tritium/helium-3 ages for water sampled from the 

principal aquifer in Salt Lake Valley, Utah, 2000-01........................................................................ 55

Figure 23. Map showing distribution of interpreted-age category for water sampled from the principal 

aquifer in Salt Lake Valley, Utah, 2000-01. ...................................................................................... 56

Figure 24. Graph showing range and distribution of apparent tritium/helium-3 age for water from the 

principal aquifer by area in Salt Lake Valley, Utah........................................................................... 57

Figure 25. Graph showing apparent chlorofluorocarbon age and apparent tritium/helium-3 age for water 

sampled from selected public-supply wells in Salt Lake Valley, Utah ............................................. 62

Figure 26. Map showing interpreted-age category, chlorofluorocarbon, anthropogenic-compound, and 

nitrate information for water sampled from 31 public-supply wells in Salt Lake Valley, 

Utah, 2001.......................................................................................................................................... 64

Figure 27. Graphs showing relation among the occurrence of anthropogenic compounds detected, nitrate

concentration, and other factors for water sampled from 31 public-supply wells in Salt Lake 

Valley, Utah, 2001 ............................................................................................................................. 66

Figure 28. Graphs showing relation of total concentration of volatile organic compounds and pesticides 

to apparent tritium/helium-3 age and to depth to top of open interval for water sampled from 

31 public-supply wells in Salt Lake Valley, Utah, 2001 ................................................................... 67
viii

Table 1. Ground-water budget for Salt Lake Valley, Utah, as reported in previous studies........................ 10

Table 2. Description of 31 public-supply wells completed in Salt Lake Valley, Utah, 2001 ...................... 11

Table 3. Quality-control sampling for 31 public-supply wells in Salt Lake Valley, Utah, 2001................. 13

Table 4. Summary of physical properties and concentration of major ions, trace elements, and nutrients 

in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001 .......................... 15

Table 5. Detection frequency and concentration of pesticides detected in water sampled from 31 publicsupply wells in Salt Lake Valley, Utah, 2001................................................................................ 16

Table 6. Detection frequency and concentration of volatile organic compounds detected in water 

sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001 ........................................ 17

Table 7. Pesticides and degradation products analyzed for in water sampled from 31 public-supply 

wells in Salt Lake Valley, Utah, 2001 ........................................................................................... 28

Table 8. Volatile organic compounds analyzed for in water sampled from 31 public-supply wells in 

Salt Lake Valley, Utah, 2001......................................................................................................... 32

Table 9. Stable-isotope data for water sampled from the principal aquifer in Salt Lake Valley, Utah, 

1990-2001 ...................................................................................................................................... 37

Table 10. Dissolved-gas and recharge-temperature data for water sampled from public-supply wells in 

Salt Lake Valley, Utah, 2000-01 ................................................................................................... 42

Table 11. Tritium/helium-3 age data for water sampled from public-supply wells in Salt Lake Valley, 

Utah, 2000-01 ................................................................................................................................ 50

Table 12. Chlorofluorocarbon age data for water sampled from 31 public-supply wells in Salt Lake 

Valley, Utah, 2001......................................................................................................................... 59

Table 13. Field parameters for water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 

2001 ............................................................................................................................................... 72

Table 14. Concentration of dissolved major ions in water sampled from 31 public-supply wells in Salt 

Lake Valley, Utah, 2001................................................................................................................ 74

Table 15. Concentration of trace elements in water sampled from 31 public-supply wells in Salt Lake 

Valley, Utah, 2001......................................................................................................................... 76

Table 16. Concentration of nutrient constituents and organic carbon in water sampled from 31 publicsupply wells in Salt Lake Valley, Utah, 2001................................................................................ 78

Table 17. Concentration of dissolved pesticides detected in water sampled from 31 public-supply 

wells in Salt Lake Valley, Utah, 2001 .......................................................................................... 79

Table 18. Concentration of volatile organic compounds detected in water sampled from 31 publicsupply wells in Salt Lake Valley, Utah, 2001................................................................................ 80

Table A-1. Quality-control data for dissolved major ions in blank water and water sampled from 

selected public-supply wells in Salt Lake Valley, Utah, 2001 ...................................................... 83

Table A-2. Quality-control data for trace elements in blank water and water sampled from selected 

public-supply wells in Salt Lake Valley, Utah, 2001 .................................................................... 84

Table A-3. Quality-control data for nutrient constituents and organic carbon in blank water and water 

sampled from selected public-supply wells in Salt Lake Valley, Utah, 2001 ............................... 86

Table A-4. Quality-control data for dissolved pesticides detected in blank water and (or) ground water 

sampled from selected public-supply wells in Salt Lake Valley, Utah, 2001 ............................... 87

Table A-5. Quality-control data for volatile compounds detected in blank water and (or) water sampled 

from selected public-supply wells in Salt Lake Valley, Utah, 2001.............................................. 88

TABLES
 ix

Table A-6. Percent recovery for pesticide surrogates in blank water and water sampled from 31 publicsupply wells in Salt Lake Valley, Utah, 2001................................................................................ 89

Table A-7. Percent recovery for volatile organic compound surrogates in blank water and water sampled 

from 31 public-supply wells in Salt Lake Valley, Utah, 2001 ...................................................... 90

Table A-8. Percent recovery for matrix spikes of pesticides in water sampled from selected publicsupply wells in Salt Lake Valley, Utah, 2001................................................................................ 91

Table A-9. Percent recovery for matrix spikes of volatile organic compounds in water sampled from 

selected public-supply wells in Salt Lake Valley, Utah, 2001 ...................................................... 94
x 

CONVERSION FACTORS AND VERTICAL DATUM

Water temperature in degrees Celsius (oC) and degrees Fahrenheit (oF) may be converted by using the 

following equations:

oF = 1.8 (oC) + 32

oC = (oF - 32) / 1.8

Vertical coordinate information is referenced to the North American Vertical Datum of 1929 (NAVD 

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

Concentration of chemical constituents in water is reported either in milligrams per liter (mg/L) or 

micrograms per liter (μg/L). Milligrams per liter and micrograms per liter are units expressing the 

concentration of chemical constituents in solution as weight (grams) of solute per unit volume (liter) 

of water. A liter of water is assumed to weigh 1 kilogram, except for brines or water at high temperatures because of changes in the density of the water. For concentrations less than 7,000 mg/L or 

7,000,000 μg/L, the numerical value is the same as for concentrations in parts per million or parts per 

billion, respectively.

Specific conductance is reported in microsiemens per centimeter at 25 degrees Celsius (μS/cm). 

Radon concentration in water is reported as picocuries per liter (pCi/L). Stable-isotope ratios are 

reported as per mil (‰), which is equivalent to parts per thousand. Tritium concentration in water is 

reported as tritium units (TU). The ratio of 1 atom of tritium to 1018 atoms of hydrogen is equal to 1 

TU or 3.2 picocuries per liter. Dissolved-gas concentrations are reported in cubic centimeters at standard temperature and pressure per gram of water (cm3STP/g). Chlorofluorocarbons measured in picograms per kilogram (pg/kg) are equivalent to parts per quadrillion. 

Multiply By To obtain

acre-feet per year (acre-ft/yr) 1,233 cubic meter per year

foot (ft) 0.3048 meter

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

gallon (gal) 3.785 liter

gallon per minute (gal/min) 3.785 liter per minute

inch (in.) 25.4 millimeter

inch per year (in/yr) 25.4 millimeters per year

mile (mi) 1.609 kilometer

square mile (mi2) 2.59 square kilometer
Abstract 1

Quality and Sources of Ground Water used for Public 

Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

By Susan A. Thiros and Andrew H. Manning

ABSTRACT

Ground water supplies about one-third of the 

water used by the public in Salt Lake Valley, Utah. The 

occurrence and distribution of natural and anthropogenic compounds in ground water used for public 

supply in the valley were evaluated. Water samples 

were collected from 31 public-supply wells in 2001 

and analyzed for major ions, trace elements, radon, 

nutrients, dissolved organic carbon, methylene blue 

active substances, pesticides, and volatile organic compounds. The samples also were analyzed for the stable 

isotopes of water (oxygen-18 and deuterium), tritium, 

chlorofluorocarbons, and dissolved gases to determine 

recharge sources and ground-water age.

Dissolved-solids concentration ranged from 157 

to 1,280 milligrams per liter (mg/L) in water from the 

31 public-supply wells. Comparison of dissolvedsolids concentration of water sampled from the principal aquifer during 1988-92 and 1998-2002 shows a 

reduction in the area where water with less than 500 

mg/L occurs. Nitrate concentration in water sampled 

from 12 of the 31 public-supply wells was higher than 

an estimated background level of 2 mg/L, indicating a 

possible human influence. At least one pesticide or pesticide degradation product was detected at a concentration much lower than drinking-water standards in water 

from 13 of the 31 wells sampled. Chloroform was the 

most frequently detected volatile organic compound 

(17 of 31 samples). Its widespread occurrence in 

deeper ground water is likely a result of the recharge of 

chlorinated public-supply water used to irrigate lawns 

and gardens in residential areas of Salt Lake Valley. 

Environmental tracers were used to determine 

the sources of recharge to the principal aquifer used for 

public supply in the valley. Oxygen-18 values and 

recharge temperatures computed from dissolved noble 

gases in the ground water were used to differentiate 

between mountain and valley recharge. Maximum 

recharge temperatures in the eastern part of the valley 

generally are below the range of valley water-table 

temperatures indicating that mountain-block recharge 

must constitute a substantial fraction of recharge to the 

principal aquifer in this area. Together, the recharge 

temperature and stable-isotope data define two zones 

with apparently high proportions of valley recharge on 

the east side of the valley.

The possibility of water samples containing a 

substantial proportion of water recharged before thermonuclear testing began in the early 1950s (pre-bomb) 

was evaluated by comparing the initial tritium concentration of each sample (measured tritium plus measured 

tritiogenic helium-3) to that of local precipitation at the 

apparent time of recharge. Three interpreted-age categories were determined for water from the sampled 

wells: (1) dominantly pre-bomb; (2) dominantly modern; and (3) modern or a mixture of pre-bomb and 

modern. Apparent tritium/helium-3 ages range from 3 

years to more than 50 years. Water generally becomes 

older with distance from the mountain front, with the 

oldest water present in the discharge area. 

The presence of anthropogenic compounds at 

concentrations above reporting levels and elevated 

nitrate concentrations (affected wells) in the principal 

aquifer is well correlated with the distribution of interpreted-age categories. All of the wells (10 of 10) with 

dominantly modern water are affected. Seventy percent (7 of 10) of the wells with dominantly modern or a 

mixture of modern and pre-bomb waters are affected. 

Only 1 of the 11 wells with dominantly pre-bomb 

water is affected. Anthropogenic compounds were not 

detected in water with an apparent age of more than 50 

years, except for water from one well. All of the samples that consisted mostly of modern water contained at 

least one anthropogenic compound.
2 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

INTRODUCTION

Ground water, primarily from deeper unconsolidated basin-fill deposits known as the principal aquifer, 

accounts for about one-third of the water used for 

public supply in Salt Lake Valley, Utah. The quality of 

water from much of the principal aquifer is generally 

suitable for drinking. However, withdrawals are regulated and limited by the Utah Division of Water Rights 

because the resource is over allocated and could be 

adversely affected by large water-level declines and 

water-quality degradation. Leakage from the shallow 

aquifer to the deeper principal aquifer in the valley is 

possible where a downward gradient exists and confining layers are thin and (or) discontinuous. Compounds 

resulting from human activities such as volatile organic 

compounds and pesticides have been frequently 

detected in shallow ground water sampled in residential 

areas where the gradient is downward to the principal 

aquifer (Thiros, 2003). Recharge from the mountains is 

considerably less likely to contain man-made chemicals and elevated dissolved-solids concentrations than 

is recharge that occurs in the valley. Continued population growth in the valley will result in an increasing 

demand for water of suitable quality for drinking and 

the potential for changes in ground-water flow directions and gradients.

Existing information on the occurrence and distribution of naturally occurring and man-made compounds in water from the principal aquifer is primarily 

from samples collected from public-supply wells by 

numerous well owners to comply with mandates of the 

Safe Drinking Water Act. A water-quality data set constructed by using consistent methods of sampling and 

analysis is needed to provide a baseline with which to 

compare data collected in the future. Additional information is also needed on when and where the water 

currently used for public supply was recharged in order 

to evaluate how susceptible the water quality is to 

change.

The chemical composition of ground water used 

for public supply in the valley was studied during 

2001-02 as part of the U.S. Geological Survey (USGS) 

National Water-Quality Assessment (NAWQA) program. The objectives of the NAWQA program are to 

describe the current water-quality conditions and trends 

in rivers, streams, and ground water and to understand 

the natural and human factors that affect the conditions 

and trends in water quality throughout the Nation. The 

Great Salt Lake Basins study unit is 1 of more than 50 

study areas selected to meet these objectives. 

Purpose and Scope

The purpose of this report is to evaluate the 

occurrence and distribution of natural and anthropogenic compounds in ground water used for public 

supply in Salt Lake Valley and to determine the general 

sources of recharge to the principal aquifer. Water samples were collected from 31 public-supply wells in 

2001 and analyzed for field parameters, major ions, 

trace elements, radon, nutrients, dissolved organic 

carbon (DOC), methylene blue active substances 

(MBAS), pesticides, and volatile organic compounds 

(VOCs). The samples also were analyzed for the stable 

isotopes of water (oxygen-18 and deuterium), tritium, 

chlorofluorocarbons, and dissolved gases to determine 

recharge sources and ground-water age.

Data from the 31 public-supply wells are augmented with data from other studies and sources in 

order to improve spatial resolution and enable a more 

comprehensive interpretation of the data. These additional data include (1) concentrations of dissolved solids, arsenic, radon, nitrate, atrazine and its degradation 

products, chloroform, and oxygen-18 in the principal 

aquifer from wells sampled for the NAWQA program 

during 1998-2000; (2) concentrations of dissolved 

solids and arsenic in the principal aquifer during 1998-

2002 obtained from the Utah Division of Drinking 

Water; (3) concentrations of dissolved solids in the 

principal aquifer in the southwestern part of the valley 

(where there are few public-supply wells) during 1998-

2002 from Kennecott Utah Copper Corporation; (4) 

oxygen-18 data from Thiros (1995) collected during 

1990-91 and from NAWQA samples collected during 

1998-2000; and (5) dissolved-gas and tritium data for 

water samples collected primarily during 2000 from 

public-supply wells on the east side of Salt Lake Valley 

(Manning, 2002).

Description of Study Area

Salt Lake Valley is an urban area bounded by the 

Wasatch Range, Oquirrh Mountains, Traverse Mountains, and Great Salt Lake (fig. 1). It is near the
3 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 1. Map showing location and geographic features of Salt Lake Valley, Utah.

Base from U.S. Geological Survey digital line graph data,

1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12 Bear

Lake

UTAH

IDAHO

WYOMING

Great

 Salt

 Lake

Utah

Lake

Salt

Lake

City

112°15'

 Great

 Salt

Lake

Tailings ponds

80

15

40°30'

40°45'

111°37'30"

Salt Lake County

Jordan River

OQUIRRH MOUNTAINS

WASATCH RANGE

Great

Salt Lake

Basins

study

area

215

0 3 6 KILOMETERS

0 3 6 MILES

Riverton

TRAVERSE

MOUNTAINS

Coon Creek

Barneys Creek

Bingham Creek

City Creek

Red

Creek

Butte

Creek

Emigration

Creek

Parleys

Creek Mill

Creek

Big Cottonwood

Creek

Little Cottonwood

Butterfield Creek

Rose

Creek

Provo Canal

Reservoir

Utah

Canal

Lake

South

Jordan

Canal

Distributing

Utah

Lake

Canal

Salt and

Canal

Draper

Irrigation

Canal

East Jordan

Canal

Jordan

Salt

Lake

and

Canal Surplus

EXPLANATION

Fault

Approximate boundary of basin-fill

deposits in Salt Lake Valley

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper
4 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

transition between the Basin and Range and Rocky 

Mountain Physiographic Provinces (Fenneman, 1931). 

The valley is about 28 mi long and 18 mi wide (about 

500 mi2) and generally corresponds to the populated 

part of Salt Lake County, which contains the Salt Lake 

City metropolitan area. The population of Salt Lake 

County in 2000 was about 898,000 (U.S. Census 

Bureau, 2002) and is growing rapidly. The population 

almost doubled between 1963 and 1994, corresponding 

to a large increase in land developed for residential and 

commercial use. Population in Salt Lake County is 

projected to be about 1,029,000 in 2010 and 1,233,000 

in 2020 (Wasatch Front Regional Council, 2000), 

which will increase water demand for public supply. 

Because the natural boundaries of the valley restrict 

expansion of residential areas beyond the extent of 

agricultural land, population growth will occur mainly 

through increased population density. 

The climate in Salt Lake Valley is semiarid, with 

a 1961-90 average annual precipitation of about 10 to 

20 in. (Daly and Taylor, 1998). Lawns and gardens in 

the valley require irrigation to supplement precipitation 

during the growing season. Precipitation in the mountains is about 50 in/yr. Mountain streams draining the 

Wasatch Range discharge into the Jordan River, which 

flows north along the axis of the valley, is diverted into 

canals, and eventually discharges into Great Salt Lake.

Land and Water Use

Urban areas within the valley more than doubled 

from 1960 (89 mi2) to 1994 (198 mi2) (Utah Department of Natural Resources, Division of Water 

Resources, 1999). Land use in urban areas of the valley 

in 1994 was about 63 percent residential, 6 percent 

commercial, 14 percent industrial, and 17 percent other 

(includes open spaces, idle spaces, transportation, and 

utilities) (Utah Department of Natural Resources, Division of Water Resources, 1995). Much of the industrial 

land use in Salt Lake Valley is near the Jordan River 

(fig. 2). Historically, the urban area was centered in the 

northeastern part of the valley in a recharge area. Many 

of the recently developed residential/commercial areas 

are along the mountain front bounding the east side of 

the valley and are also replacing agricultural areas on 

the west side (fig. 2).

Surface water from streams draining the Wasatch 

Range provided about 70 percent of the water used for 

public supply in Salt Lake Valley in 2000. This water is 

chlorinated and distributed across the valley. Demand 

for water peaks during July through August, when 

lawns and gardens require more water because of the 

summer heat. Water systems that receive surface water 

also use wells during the summer to meet the increased 

demand. Water systems without surface-water sources 

rely on water from wells throughout the year. Groundwater withdrawal in 2000 from wells in the valley was 

about 28 percent of the public supply. Springs and tunnels in the Wasatch Range provided a minor amount 

(about 2 percent) of the valley’s public supply.

An average of about 79,000 acre-ft/yr was withdrawn from 161 public-supply wells in the valley 

during 1996-99 (Utah Division of Water Rights, written 

commun., 2001). The average well withdrawal for this 

period is shown in figure 3. Most of the ground-water 

withdrawal occurs on the east side of the valley 

because of higher yields and lower dissolved-solids 

concentrations. In some areas, water is blended with 

water from other sources to improve its quality. 

Ground-Water Hydrology

Salt Lake Valley contains basin-fill deposits 

derived from the surrounding mountains that are deposited mainly in alluvial fans, stream channels, deltas, 

and lacustrine features associated with Lake Bonneville 

and other paleolakes. Lake Bonneville covered much of 

northern Utah about 15,000 years ago. Tertiary-age 

deposits are semiconsolidated to consolidated and consist mainly of alluvial-fan deposits interbedded with 

volcanic ash and tuffs. These deposits crop out along 

the western and southern margins of the valley and are 

overlain by generally unconsolidated sediments of 

Quaternary age that are considerably more permeable. 

The saturated Quaternary deposits range from less than 

200 ft thick along the margins of the valley to more 

than 1,000 ft thick in the northern part of the valley 

(Hely and others, 1971). Nearly all the wells in the 

valley are screened in the Quaternary deposits. Lakedeposited clay layers occur throughout the valley, 

except near the mountain fronts where coarser-grained 

deposits exist. 
Introduction 5

Figure 2. Map showing Land use in Salt Lake Valley, Utah, 1994.

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Tailings ponds

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

EXPLANATION

Water

Riparian

Agriculture

Corn

Unknown

Approximate boundary of basin-fill deposits in Salt Lake Valley

112°07'30" 111°48'

SALT LAKE COUNTY

UTAH COUNTY

Residential

Commercial

Industrial

Transportation/utilities

Open or idle

Excavated

Great

Salt

Lake

Discharge area

Secondary recharge area

OQUIRRH MOUNTAINS

Primary recharge area

WASATCH RANGE

TRAVERSE MOUNTAINS

Discharge area

Secondary recharge area harge area

Primary Primary recharge area
6 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 3. Map showing Average ground-water withdrawals from public-supply wells in Salt Lake Valley, Utah, 1996-99.

EXPLANATION

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill

deposits in Salt Lake Valley

Public-supply well sampled as part of

this study

Withdrawals from public-supply wells, in acre-feet per year

2 – 100

100 – 500

500 – 1,000

1,000 – 1,500

1,500 – 2,480

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

Tailings ponds

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

DAVIS COUNTY

SALT LAKE COUNTY

UTAH COUNTY

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
Study Design and Methods 7

A generalized model of the saturated basin-fill 

deposits in Salt Lake Valley consists of a relatively 

deep unconfined aquifer near the mountain fronts that 

becomes confined toward the center of the valley by 

layers of fine-grained deposits (fig. 4). Collectively, the 

deeper aquifers are known as the principal aquifer. 

Where the principal aquifer is confined, it is overlain 

by a shallow unconfined aquifer. The primary recharge 

area for the principal aquifer includes the mountains 

surrounding the valley and the part of the valley near 

the mountain fronts where there are no substantial 

layers of fine-grained deposits to impede the downward 

movement of water. The secondary recharge area is 

where downward movement of water from the shallow 

aquifer to the deeper confined aquifer is possible 

because a downward gradient exists and confining 

layers are thin, and (or) discontinuous. In the discharge 

area an upward gradient exists from the deeper confined aquifer to the overlying shallow aquifer. The 

recharge and discharge areas in Salt Lake Valley (fig. 

5) were mapped by Anderson and others (1994, p. 6) 

on the basis of lithologic and water-level data.

Depending on the continuity of the confining 

layers, the shallow ground water overlying these layers 

may be either localized in extent (perched) or laterally 

continuous forming an aquifer. The shallow aquifer is 

susceptible to contamination from activities related to 

land use because of its proximity to land surface. Water 

quality in the confined part of the principal aquifer can 

be degraded by secondary recharge of contaminated 

water from the shallow aquifer. The unconfined part of 

the principal aquifer also is vulnerable because of a 

lack of confining layers that can impede the downward 

movement of contaminated ground water. The principal 

aquifer in Salt Lake Valley has been divided into areas 

where the susceptibility of ground water to contamination is similar on the basis of differences in geology, 

the rate of ground-water movement, and the direction 

of vertical hydraulic gradients (Waddell and others, 

1987a).

Recharge to and discharge from the principal 

aquifer in the valley has been estimated in previous 

studies by Hely and others (1971), Waddell and others 

(1987b), and Lambert (1995) (table 1). Mountain-front 

recharge is thought to comprise about 50 percent of 

recharge to the principal aquifer and includes subsurface inflow from the adjacent mountains (mountainblock recharge) and seepage from streams near the 

mountain front. Infiltration of unconsumed irrigation 

water from fields, lawns, and gardens; infiltration of 

precipitation on the valley floor; and seepage from 

canals are the other major sources of recharge. Model 

simulations of the ground-water flow system were used 

to better understand the distribution of these recharge 

components in the valley (Waddell and others, 1987b; 

Lambert, 1995). Seepage through the shallow aquifer 

to the Jordan River and other streams and to evapotranspiration are large components of discharge from 

the principal aquifer. Total withdrawals from wells for 

all uses is about one-third of the total estimated discharge from the system and affects the amount of 

ground water available to other forms of discharge.

Acknowledgments

The USGS thanks the well owners who allowed 

USGS personnel access to their wells for sampling. 

The assistance of Alan Rigby and Kip Solomon at the 

University of Utah Department of Geology and Geophysics, Tritium and Noble Gases Laboratory also is 

appreciated.

STUDY DESIGN AND METHODS

Site Selection

This study consisted of sampling 15 publicsupply wells completed in the principal aquifer in Salt 

Lake Valley that withdraw the most water and therefore 

supply the most people. An average annual withdrawal 

based on 1996-99 data (Utah Division of Water Rights, 

written commun., 2001) was used to rank the publicsupply wells. Withdrawal from wells within 0.62 mi (1 

kilometer) of each other was totaled for ranking purposes and one well was chosen from the group to be 

sampled. Water from the 15 public-supply wells and 

associated nearby wells accounts for 46 percent of the 

water from wells used for public supply in the valley. 

An additional 16 public-supply wells were selected to 

provide a better spatial distribution across the valley. A 

minimum spacing of 0.62 mi was required between 

wells. The 31 sampled public-supply wells completed 

in the principal aquifer are shown in figures 3 and 5 and 

described in table 2.
8 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

The 31 sampled public-supply wells ranged from 

130 to 1,212 ft deep with a median depth of 500 ft. The 

top of the open intervals in the wells varied from 90 to 

650 ft below land surface and typically included more 

than one open interval. For this report, Salt Lake Valley 

is divided into an east and west side with the area 

around the Jordan River included on the east side 

because of probable ground-water origin. Twenty-three 

of the wells sampled are on the east side and eight are 

on the west side of the valley. Because the groundwater system is not the same on the east and west sides 

of the valley, the primary and secondary recharge areas 

and the discharge area were distinguished between east 

and west sides.

Sample Collection

Ground-water samples were collected during 

May and June 2001 to analyze for major ions, alkalinity, radon, nutrients, DOC, MBAS, oxygen-18, deuterium, selected nutrients, trace elements, pesticides, and 

VOCs and were processed according to protocols in 

Koterba and others (1995). Most of the public-supply 

wells had been pumping during the summer and each 

well was purged of at least three to five casing volumes 

of water prior to sampling. Water temperature, pH, specific conductance, dissolved oxygen, turbidity, and discharge were monitored periodically during the purge 

cycle. Ground-water samples were collected after measurements of these parameters had stabilized.

Figure 4. Generalized block diagram showing the basin-fill deposits and ground-water flow system in Salt Lake Valley, Utah.

Basin-fill deposits of

Tertiary age

Great

 Salt

 Lake

Fine-grained

deposits

Consolidated

rock

Water level

in shallow aquifer

Water level in

deeper confined aquifer

Deeper

confined

aquifer

Shallow

aquifer

Confining layer

Primary

recharge

area

Perched

water

Secondary

recharge area

Discharge

area

EXPLANATION

Direction of ground-water movement

Deeper

unconfined

aquifer

Water level in

deeper unconfined

aquifer

Coarse-grained

deposits

Principal

aquifer

Basin-fill deposits of

Quaternary age Modified from Hely and others, 1971
9 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 5. Map showing location of ground-water recharge and discharge areas and 31 sampled public-supply wells, and approximate direction of 

horizontal ground-water flow in Salt Lake Valley, Utah, 2001.

4,600

4,700

4,800

4,500

4,600

4,300

4,400

4,500

4,400

5,400

5,300

5,200

5,100

5,000

4,900

4,800

4,700

4,600

4,500

4,400

5,500

5,600

4,600

4,500

4,700

4,800

4,900

4,300

EXPLANATION

Dominantly clastic sedimentary rocks and

carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Discharge area

Primary recharge area

1

2

13 4

5

6

7

8

10 11

9

14

20

17

25

24

30

31

23

18

22

29

27 26

28

12

19

21

22

15

16

3

Secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Approximate direction of horizontal ground-water flow

Potentiometric contour—Shows altitude of model-computed potentiometric

surface for the principal aquifer in 1991 (from Lambert, 1995, fig. 25). Contour

interval is 100 feet. Datum is sea level

Public-supply well sampled as part of this study—Number is well identifier

Public-supply well not sampled as part of this study

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

Tailings ponds

40°30'

40°45'

Jordan River

0 2 4 KILOMETERS

0 4 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

DAVIS COUNTY

SALT LAKE COUNTY

UTAH COUNTY

4,500

2

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill

Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
10 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Ground-water samples from the 31 public-supply 

wells also were analyzed for chlorofluorocarbons 

(CFCs). Analyzed CFCs include CFC-11 (trichlorofluoromethane or CFCl3), CFC-12 (dichlorodifluoromethane or CF2Cl2), and CFC-113 

(trichlorotrifluoroethane or C2F3Cl3). To avoid contact 

with air, water was directed from the well’s discharge 

line through copper tubing to a valve system that 

allowed for filling and flushing of a borosilicate 

ampoule. Headspace above the sample was filled with 

CFC-free ultrapure nitrogen gas before the ampoule 

was fused closed. Five ampoules were filled at each 

sampled well in case of breakage or leakage.

As part of this study, dissolved-gas samples from 

24 of the 31 public-supply wells were collected by 

using clamped copper tubes, a standard sampling technique described by Stute and Schlosser (2000). Samples were collected while the well was operating. 

Copper tubing (5/8-in. diameter) was plumbed directly 

to a tap in the well discharge line, and flow through the 

tubing was regulated with a downstream valve. The 

well pump provided substantial backpressure in the 

tubing, preventing gas loss. After several minutes of 

purging, the sample was isolated in the copper tubing 

by using pinch-off clamps. 

Dissolved-gas samples from 50 public-supply 

wells on the east side of Salt Lake Valley were collected in the summer of 2000 as part of a previous 

study by Manning (2002) and included samples from 

the 7 public-supply wells not sampled for dissolved 

gases in this study and 5 wells that were sampled as 

part of both studies. This data set was included to

Table 1. Ground-water budget for Salt Lake Valley, Utah, as reported in previous studies

[Reported in acre-feet per year]

Estimated for

1964-68

(Hely and others,

1971, table 21)

Specified or computed

in Waddell and others

(1987b, tables 1 and 3)

numerical model

steady-state simulation

Specified or computed

in Lambert

(1995, table 5)

numerical model

steady-state

simulation

Recharge from

Consolidated rock 135,000 154,000 142,000

Irrigated fields, lawns, and gardens 98,000 76,000 57,000

Precipitation 60,000 70,000 67,000

Canals 48,000 24,000 30,000

Streams and channel fill 21,500 17,500 16,000

Underflow at Jordan Narrows 2,500 2,500 2,500

Seepage from tailings ponds near Magna 2,400 0 0

Reinjection from air conditioning 2,000 2,000 10

Reservoirs and evaporation ponds 0 0 1,900

Jordan River and tributaries 0 0 1,000

Total (rounded) 369,000 346,000 317,000

Discharge to

Jordan River and tributaries 170,000 146,000 137,000

Wells 107,000 102,000 105,000

Evapotranspiration 60,000 54,000 36,000

Springs 21,000 21,000 19,000

Drains 5,000 5,000 10,000

Great Salt Lake 4,000 7,200 1,300

Canals 0 10,000 9,200

Total (rounded) 367,000 2345,000 317,000 1 Amounts reinjected were subtracted from amounts pumped for same wells.

2 Previously reported in Waddell and others (1987b, table 3) as 346,000.
Study Design and Methods 11

better understand the sources of recharge to the 

principal aquifer on the east side of Salt Lake Valley. 

Samples were collected by using passive diffusion 

samplers similar to those used in Sanford and others 

(1996). These in-situ sampling devices consist of a 

length of copper tubing (3/16-in. diameter) sealed at 

one end and connected to a sealed length of silicone 

tubing at the other. Samplers are placed in the water 

and left for an adequate period to allow dissolved gases 

to equilibrate with the sampler headspace by diffusion 

through the silicone tubing. Samplers are then 

removed from the water and the copper tubing is 

immediately sealed, either with a valve or by crimping 

(cold weld). Samples were collected while the wells 

were pumping, and most wells had been pumping for at 

least 48 hours prior to sampling. Samplers were placed 

within a flow-through cell plumbed directly into the 

wellhead. The well pump provided significant pressure 

in the flow-though cell, preventing gas loss. Flow rates 

through the cell were maintained at about 1 gal/min 

throughout the 24-hour (minimum) equilibration 

period. Diffusion samplers were then removed and 

sealed immediately by crimping.

Table 2. Description of 31 public-supply wells completed in Salt Lake Valley, Utah, 2001

[—, no data]

Well 

identifier 

(fig. 5)

Area of valley and 

classification of groundwater recharge and 

discharge areas

(fig. 5)

Normal 

pumping 

period

1996-99 

average

withdrawal for 

public supply 

near

sampled well

(acre-feet per 

year)

Well 

depth

Top of 

openings

Bottom of 

openings

Surface seal 

installed

Sand or 

gravel 

pack

Static 

water 

level

Pumping 

water 

level

(feet below land surface)

1 east - discharge year 3,889 678 280 656 0-120 no 40 180

2 east - secondary recharge year 3,703 544 265 533 — no 185 200

3 east - discharge summer 2,868 935 650 872 0-120 120-935 54 217

4 east - secondary recharge year 2,593 650 395 648 — — 279 326

5 east - secondary recharge summer1 2,403 861 440 851 0-380 380-877 135 285

6 west - primary recharge summer 2,208 590 380 590 surface casing yes 184 113

7 west - secondary recharge summer 2,005 500 290 480 0-100 — 212 347

8 east - primary recharge summer1 1,920 950 610 950 0-220 220-960 499 590

9 east - discharge summer 1,799 965 395 945 0-112 112-980 5 178

10 west - discharge summer 1,684 250 90 232 0-65 65-250 artesian 32

11 east - discharge summer 1,609 1,000 418 994 0-405 405-1,004 artesian 70

12 east - secondary recharge summer 1,470 453 256 451 no no 290 304

13 east - secondary recharge summer1 1,466 700 275 680 — — 312 378

14 west - discharge summer 1,459 177 96 173 0-36 36-106 artesian 80

15 east - secondary recharge summer 1,440 506 154 495 — — 136 154

16 east - primary recharge summer 838 464 162 420 — — 144 —

17 east - primary recharge summer 1,265 510 266 470 — — 194 280

18 east - secondary recharge summer 1,288 502 160 490 0-113 no 31 96

19 east - secondary recharge summer 907 657 295 650 surface casing no 116 130

20 east - discharge summer 333 386 240 380 0-123 no 13 130

21 east - secondary recharge summer 606 701 200 545 0-120 no 73 109

22 west - secondary recharge year 939 410 220 390 0-160 160-410 122 224

23 west - primary recharge summer 635 610 330 603 0-200 200-620 199 265

24 west - secondary recharge year 304 900 360 890 0-120 120-900 174 —

25 west - primary recharge summer 393 1,212 635 1,202 0-145 145-1,212 426 541

26 east - secondary recharge summer 531 590 295 532 0-100 100-549 69 335

27 east - discharge summer 254 468 125 460 — — 51 109

28 east - discharge year 832 840 145 340 0-100 100-840 artesian 175

29 east - secondary recharge summer 543 515 205 498 0-100 no 199 259

30 east - discharge year 5 130 130 130 no no -11 —

31 east - discharge summer 631 496 100 156 surface casing no 16 63

1 Well also is used to inject surface water into the principal aquifer.
12 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Sample Analysis

The USGS National Water-Quality Laboratory 

(NWQL) in Denver, Colorado, analyzed the water samples for major ions, radon, DOC, MBAS, selected 

nutrients, trace elements, pesticides, and VOCs. Analytical methods used for major ions and trace elements 

were primarily inductively coupled plasma/mass spectrometry, atomic adsorption spectrometry, or ion chromatography, and are described in Fishman and 

Friedman (1989), Fishman (1993), and Faires (1993). 

Nutrient concentrations were determined by colorimetry (Fishman, 1993; Patton and Truitt, 1992). DOC was 

analyzed for by using ultraviolet-promoted persulfate 

oxidation and infrared spectrometry (Brenton and 

Arnett, 1993), and radon was analyzed for by using 

liquid scintillation (American Society for Testing and 

Materials, 1996). Water samples were analyzed for 47 

pesticides by using capillary column gas chromatography/mass spectrometry (GCMS) (Zaugg and others, 

1995), for 65 pesticides by using high-performance 

liquid chromatography/mass spectrometry (HPLC) 

(Furlong and others, 2001), and for 85 VOCs by using 

purge and trap capillary column gas chromatography/mass spectrometry (Conner and others, 1998). 

MBAS analysis was used to determine the concentration of anionic sulfate and sulfonate-based surfactants 

in unfiltered samples as described by Burkhardt and 

others (1995). Alkalinity was determined on-site by 

incremental titration of filtered sample water with sulfuric acid.

Analyses of the stable isotopes of water (deuterium and oxygen-18) were done at the USGS Stable 

Isotope Laboratory in Reston, Virginia. The deuterium 

analysis uses a hydrogen equilibration method (Coplen 

and others, 1991), and the oxygen-18 analysis uses a 

carbon dioxide equilibration technique (Epstein and 

Mayeda, 1953). Analytical uncertainties for delta deuterium and delta oxygen-18 values are 2 and 0.2 per 

mil, respectively. CFCs were analyzed for at the USGS 

CFC Laboratory in Reston, Virginia, by using purge 

and trap gas chromotography (Busenberg and Plummer, 1992). The detection limit for CFCs is about 0.3 

pg/kg of water, which is equivalent to 0.3 parts per quadrillion (Plummer and Friedman, 1999).

The water samples were analyzed for tritium and 

dissolved gases by the University of Utah Department 

of Geology and Geophysics, Tritium and Noble Gases 

Laboratory in Salt Lake City, Utah. Tritium concentrations were determined by helium ingrowth (Bayer and 

others, 1989). This method involves degassing the sampled water and isolating it under a vacuum in a special 

container. The degassed sample is stored from 1 month 

to 1 year and then the concentration of helium-3 (3He), 

the radioactive decay product of tritium, is measured by 

using a magnetic sector-field mass spectrometer. The 

USGS Isotope Tracers Project Laboratory in Menlo 

Park, California, analyzed 13 samples for tritium to 

compare concentrations collected for different studies 

and laboratories. Tritium concentration in these samples was determined by using electrolytic enrichment 

and liquid scintillation (Thatcher and others, 1977) 

with a minimum-reporting limit of about 0.3 TU.

The dissolved gases nitrogen, neon, argon, and 

krypton were measured by using a quadrapole mass 

spectrometer. Helium-3 and 4 (4He) analyses were 

done by using a magnetic sector-field mass spectrometer. Dissolved gases were extracted initially from samples collected in clamped copper tubes by using the 

procedure detailed in Bayer and others (1989) (this step 

was not required for the diffusion samplers). Gases 

were inlet directly into a high vacuum purification 

system that includes a titanium/zirconium sponge for 

reactive gases. Non-reactive gases were cryogenically 

separated. Nitrogen was measured dynamically by 

using a leak valve and the remaining gases were measured statically. 

Constituents that are not detected in a water 

sample are reported as less than the minimum reporting 

level (MRL). The MRL is defined by the NWQL 

(Timme, 1995) as the smallest measured concentration 

of a constituent that may be reliably measured by using 

a given analytical method. VOCs that are not detected 

in a water sample are reported as less than the laboratory reporting level (LRL). The LRL for each VOC 

represents the minimum concentration that can be identified, measured, and reported with 99 percent confidence (Childress and others, 1999). The MRL or LRL 

for each constituent or compound indicates relative 

analytical precision and detection sensitivity, but some 

concentrations are reported as less than the reporting 

level if the identification criteria for the method were 

met. Concentrations for detections less than the MRLs 

or LRLs are designated as estimated values. Overall, 

the MRLs for pesticides and LRLs for VOCs analyzed 

for by the NAWQA program are lower than those of 

analyses done for regulatory purposes. 
Study Design and Methods 13

Quality Assurance

A quality-assurance program was used in the 

field (Koterba and others, 1995) and in the laboratory 

to evaluate the bias and variability of the analytical 

results and to ensure data reliability. Quality-control 

samples collected as part of sampling the 31 wells are 

listed in table 3. Analytical results for the quality-assurance samples are listed in tables A-1 to A-9 (appendix). 

Field-blank samples were collected to evaluate 

contamination introduced during sample collection, 

processing, shipment, and analysis. Blank water 

assumed to have less than the MRL or LRL for the analyzed constituents and compounds was pumped 

through the tubing and other sampling equipment with 

a peristaltic pump. Relatively small volumes of blank 

water flowed through the sampling equipment prior to 

collection of a field-blank sample, whereas a much 

larger amount of ground water flowed through the 

system prior to collection of a ground-water sample. 

This additional rinsing likely reduces the concentration 

of contaminants that may remain in the equipment after 

cleaning compared to the rinse provided prior to collection of a field-blank sample.

The trace elements thallium and zinc were 

detected in one field-blank sample each (table A-2 in 

appendix) at concentrations in the range of those 

detected in the ground-water samples; therefore, the 

ground-water data may be biased. Antimony, copper, 

lead, and lithium also were detected in one or more 

blank samples but at concentrations less than those 

detected in the ground-water samples. 

DOC, nitrate plus nitrite, and nitrite were 

detected in water from one field-blank sample at very 

low concentrations (table A-3 in appendix). Because 

DOC was not detected in the source-solution blank 

samples, it likely results from insufficient rinsing (1 to 

3 gal) to remove residual cleaning agents from the sampling equipment. Additional rinsing with ground water 

during the purging cycle of sampling (generally more 

than 20 gal) likely reduces DOC, nitrate, and nitrite 

concentrations in the environmental samples to below 

those determined for the field blanks. Therefore, concentrations measured for these constituents are 

assumed to be uncontaminated.

None of the 103 pesticides and pesticide breakdown products analyzed for in the field-blank samples 

were detected. Caffeine, a compound included in the 

sample analysis for pesticides, was detected in one of 

the field-blank samples (table A-4 in appendix). It also 

was detected in water sampled from two public-supply 

wells at concentrations similar to that estimated in the 

field blank; therefore, caffeine was not included in the 

pesticide data analysis. Bromacil and metolachlor were 

detected in one ground-water sample each. Estimated 

concentrations for these compounds were so small relative to the MRLs that they were not included in the data 

analysis. Carbofuran was analyzed for by using both 

the GCMS and HPLC methods. Although detected 

with the GCMS method at a low concentration in one 

environmental sample, it was not detected with the 

HPLC method that has a lower MRL; therefore, carbofuran was not included in the data analysis.

The VOC dichloromethane was detected in the 

equipment-blank sample and in one field-blank sample 

(table A-5 in appendix) at concentrations in the range 

of those estimated for two ground-water samples.

Table 3. Quality-control sampling for 31 public-supply wells in Salt Lake Valley, Utah, 2001

[DOC, Dissolved organic carbon; MBAS, methylene blue active substances; VOCs, volatile organic compounds; GCMS, gas chromatography/mass 

spectrometry; HPLC, high-performance liquid chromatography]

Type of sample Number of 

samples Constituents or compounds analyzed for

Equipment blank 1 Major ions, nutrients, DOC, MBAS, trace elements, pesticides, VOCs

Field blank 3 Major ions, nutrients, DOC, MBAS, trace elements, pesticides, VOCs

Source-solution blank 4 DOC, VOCs

Trip blank 1 VOCs

Replicate 3 Major ions, nutrients, DOC, MBAS, trace elements, radon, pesticides, VOCs

Field spike 3 VOCs, pesticides analyzed by GCMS method

Laboratory spike 3 Pesticides analyzed by HPLC method
14 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Other VOCs that have similar uses also were detected 

in the two ground-water samples, but not in the blank 

samples. The dichloromethane detected in these 

samples therefore is assumed not to be introduced 

during sampling and was used in the VOC data 

analysis. Toluene was detected in most of the blank 

samples (equipment, field, and source-solution) (table 

A-5 in appendix) and environmental samples at similar 

concentrations and is possibly the result of sample vial 

contamination. Toluene detections were not used in the 

VOC data analysis. Benzene was detected in a sourcesolution blank sample and in a ground-water sample at 

similar trace concentrations. This compound could be 

introduced into the source-solution sample when the 

blank water was poured into the sample vial. The 

atmosphere can receive benzene from the incomplete 

combustion of gasoline used to power the generator or 

nearby vehicles. The benzene detected in the groundwater sample may be from the atmosphere rather than 

the aquifer and caution should be used when 

interpreting these data. 

Trichloroethylene was detected in the trip-blank 

sample and in two ground-water samples at similar 

concentrations. Tetrachloroethylene was detected with 

trichloroethylene in the ground-water samples. Both 

compounds have similar uses and trichloroethylene can 

be formed from the degradation of tetrachloroethylene. 

Therefore the occurrence of trichlorethylene in the two 

ground-water samples is probably not the result of contamination and the data were used in the VOC data 

analysis. 

Sequential replicate ground-water samples were 

collected from three wells to determine the concentration variability for major ions, nutrients, DOC, MBAS, 

trace elements, and radon (tables A-1, A-2, and A-3 in 

appendix). Concentrations for most constituents in the 

sample pairs generally were within 10 percent. Nickel 

concentration in water from one replicate sample was 

more than five times greater than was measured in the 

original sample and may be related to contamination.

Surrogate pesticide compounds and VOCs were 

added in known concentrations to all of the groundwater and blank-water samples at the laboratory and 

percent recovery was determined for each surrogate 

(tables A-6 and A-7 in appendix). These surrogate 

compounds are similar chemically to other compounds 

that were analyzed and provide information on samplematrix effects and analyte recovery. Recovery of the 

surrogates from most of the samples was within 25 percent of the amount added to the water.

Spike solutions containing known concentrations 

of target VOCs and pesticide compounds were added to 

three sets of replicate ground-water samples (tables A8 and A-9 in appendix) to determine analyte recovery 

in the sample matrix and to evaluate the effectiveness 

of the analytical methods for selected analytes. Recovery of most target compounds was within 25 percent of 

the amount present in the unspiked sample plus the 

amount added in the spike solution. A low mean recovery generally means that the compound may not have 

been detected in ground water if present at low concentrations or that detected concentrations may be biased 

low. A high mean recovery generally means that detection is real, but the concentration may be biased high. 

Recovery of the atrazine degradation products deethylatrazine and 2-hydroxyatrazine was less than (55 percent mean recovery) and greater than (118 percent 

mean recovery), respectively, the amount added to the 

three matrix-spiked samples. Degradation from one 

form to another may have occurred in the sample 

during the time between collection and analysis.

GROUND-WATER QUALITY

Water-quality data collected from the 31 publicsupply wells sampled in Salt Lake Valley consist of 

field parameters, major ions, trace elements, nutrients, 

DOC, MBAS, pesticides, and VOCs. Summary statistics for field parameters, major ions, trace elements, 

nutrients, DOC, and MBAS are listed in table 4; 

detected pesticides are in table 5; and detected VOCs 

are in table 6. The analytical results are listed in tables 

13 to 18 at the back of the report. A more detailed discussion is presented in the following sections. Waterquality data for the principal aquifer collected for the 

NAWQA program from wells other than the 31 publicsupply wells sampled during this study are shown in 

the following figures. Water-quality data for these 

wells also are available on the Internet at http://waterdata.usgs.gov/ut/nwis/qwdata.

Concentrations of water-quality constituents and 

compounds are compared to drinking-water standards 

set by the U.S. Environmental Protection Agency 

(USEPA) for 2002 (U.S. Environmental Protection 

Agency, 2002). The maximum contaminant level 

(MCL) is the maximum concentration of a contaminant 

permissible in a public-water system. MCLs are based 

on a level at which no known or anticipated adverse
Ground-Water Quality 15

T

Table 4. Summary of physical properties and concentration of major ions, trace elements, and nutrients in water sampled from 31 public-supply wells in 

Salt Lake Valley, Utah, 2001—Continued

Property or constituent, 

and reporting unit

Number of 

detections

Minimum 

reporting 

level

Minimum Maximum Median

USEPA drinking-water 

standard or health 

advisory1

Physical properties

Well depth (feet) 31 — 130 1,212 590 —

Pumping water level (feet) 28 — 32 590 190 —

Water temperature (oC) 31 — 9.5 30.5 14.5 —

Specific conductance (μS/cm at 25 oC) 31 — 250 2,030 880 —

pH (standard units) 31 — 7.0 8.0 7.4 6.5—8.5 (SDWR)

Alkalinity (mg/L as CaCO3) 31 — 84 302 174 —

Oxygen, dissolved (mg/L) 31 — .3 9.9 5.7 —

Turbidity (Nephelometric turbidity units) 31 — .1 .5 .1 —

Major ions (mg/L, except as indicated)

Bicarbonate (as HCO3) 31 — 103 369 198 —

Bromide, dissolved 31 .01 .01 .30 .09 —

Calcium, dissolved 31 .01 25.9 172 63.5 —

Chloride, dissolved 31 .1 8.6 308 77.2 250 (SDWR)

Fluoride, dissolved 31 .2 E 0.1 .8 .3 4 (MCL); 2 (SDWR)

Iron, dissolved (μg/L) 7 10 <10 320 <10 300 (SDWR)

Magnesium, dissolved 31 .008 7.28 55.3 24.8 —

Manganese, dissolved (μg/L) 6 3.0 E 1.8 160 <3.0 50 (SDWR)

Potassium, dissolved 31 .09 1.42 34.7 2.97 —

Silica, dissolved 31 .1 9.9 105 17.6 —

Sodium, dissolved 31 .1 8.0 330 41.4 —

Sulfate, dissolved 31 .1 11.1 285 75.5 250 (SDWR)

Dissolved solids, sum of constituents 31 — 146 1,240 504 500 (SDWR)

Dissolved solids, residue at 180 oC 31 10 157 1,280 496 500 (SDWR)

Trace elements (μg/L, except as indicated)

Aluminum, dissolved 7 1 <1 8 <1 50-200 (SDWR)

Antimony, dissolved 28 .05 E .03 .17 .10 6 (MCL)

Arsenic, dissolved 31 .2 .4 17.9 1.1 10 (MCL)

Barium, dissolved 31 1.0 19.6 774 77.7 2,000 (MCL)

Beryllium, dissolved 0 .06 <.06 <.06 <.06 4 (MCL)

Boron, dissolved 31 7 11 284 57 600 (HAL)

Cadmium, dissolved 20 .04 E .02 .20 .04 5 (MCL)

Chromium, dissolved 25 .8 E .4 4.6 <.8 2100 (MCL)

Cobalt, dissolved 31 .02 .03 .27 .10 —

Copper, dissolved 31 .2 .4 6.3 1.6 1,000 (SDWR)

Lead, dissolved 29 .08 <.08 2.70 .46 —

Lithium, dissolved 31 .3 1.2 143 14.7 —

Molybdenum, dissolved 31 .2 .4 8.6 2.0 40 (HAL)

Nickel, dissolved 14 .06 E .04 3.02 <.06 100 (HAL)

Table 4. Summary of physical properties and concentration of major ions, trace elements, and nutrients in water sampled from 31 public-supply wells in 

Salt Lake Valley, Utah, 2001

[USEPA, U.S. Environmental Protection Agency; —, not applicable or no standard; oC, degrees Celsius; μS/cm, microsiemens per centimeter; SDWR, 

secondary drinking-water regulations; mg/L, milligrams per liter; E, estimated; MCL, maximum contaminant level; <, less than; μg/L, micrograms per liter; 

HAL, lifetime health-advisory level; pCi/L, picocuries per liter]
16 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Trace elements (μg/L, except as indicated)—Continued

Radon-222, total (pCi/L) 31 26 251 1,980 702 300 (MCL)

Selenium, dissolved 28 .3 E .2 3.2 .9 50 (MCL)

Silver, dissolved 0 1.0 <1.0 <1.0 <1.0 100 (SDWR and HAL)

Strontium, dissolved 31 .08 179 1,730 631 4,000 (HAL)

Thallium, dissolved 14 .04 E .02 .17 <.04 2 (MCL); .5 (HAL)

Uranium, dissolved 31 .02 .04 15.1 3.10 30 ( MCL)

Vanadium, dissolved 31 .2 .4 19.2 1.7 —

Zinc, dissolved 31 1 1 35 5 5,000 (SWDR); 2,000 (HAL)

Nutrients (mg/L)

Ammonia, dissolved as N 5 .040 <.040 2.24 <.040 30 (HAL)

Ammonia plus organic nitrogen, dissolved 

as N

7 .10 E .06 2.5 <.10 —

Carbon, organic, dissolved as C 14 .30 <.15 1.2 <.30 —

Methylene blue active substances, total 2 .02 <.02 .02 <.02 —

Nitrite, dissolved as N 12 .006 E .003 .01 <.006 1 (MCL)

Nitrate plus nitrite, dissolved as N 31 .050 E .026 5.99 1.33 10 (MCL)

Phosphorus, dissolved as P 31 .006 E .004 .132 .013 —

Orthophosphorus, dissolved as P 19 .020 E .009 .105 .030 —

1 U.S. Environmental Protection Agency (2002).

2 MCL is for total chromium.

Table 5. Detection frequency and concentration of pesticides detected in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

[Concentrations reported in micrograms per liter; E, estimated value; —, not applicable or no applicable standard; Maximum contaminant level is the U.S. 

Environmental Protection Agency established drinking-water standard (U.S. Environmental Protection Agency, 2002). Lifetime health advisory level is 

defined as the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for a lifetime of exposure (U.S. 

Environmental Protection Agency, 2002)]

Pesticide Trade name(s) Predominant uses Number of 

detections

Minimum 

reporting 

level

Maximum 

concentration

Minimum 

detected 

concentration

Maximum 

contaminant 

level

Lifetime 

health 

advisory 

level

Atrazine AAtrex Restricted use 

herbicide

7 0.007 0.034 E 0 .002 13 3

Deethylatrazine DEA, Desethylatrazine Degradation product of 

atrazine

10 .006 E .065 E .002 — —

Deethyldeisopropylatrazine — Degradation product of 

atrazine

1 .01 E .01 — —

Imazethapyr Pursuit Herbicide 2 .017 E .014 E .006 — —

1 Maximum contaminant level is under review. 

Table 4. Summary of physical properties and concentration of major ions, trace elements, and nutrients in water sampled from 31 public-supply wells in 

Salt Lake Valley, Utah, 2001—Continued

Property or constituent, 

and reporting unit

Number of 

detections

Minimum 

reporting 

level

Minimum Maximum Median

USEPA drinking-water 

standard or health 

advisory1
Ground-Water Quality 17

effects on human health occur and which allows an 

adequate margin of safety, but also considers the cost 

and feasibility of meeting the standard. The lifetime 

health advisory level (HAL) is the concentration of a 

chemical in drinking water at or below which is not 

expected to cause any adverse noncarcinogenic effects 

during a lifetime of exposure (U.S. Environmental 

Protection Agency, 2002). It is based on health effects 

information and is provided as technical guidance for 

regulatory and management officials.

The water samples analyzed for this study were 

collected near the wellhead before treatment or distribution, and represent source water. Water used for 

public supply is required to meet drinking-water standards before distribution to users. Finished water supplied to the public may have undergone treatment or 

dilution to meet these standards. 

Physical Properties

Physical properties measured in the field during 

sampling of water from the public-supply wells 

included temperature, specific conductance, pH, alkalinity, dissolved oxygen, and turbidity (table 4 and table 

13). The median water temperature was 14.5oC and 

ranged from a median value of 16oC for water from 

wells in the central discharge area near the Jordan 

River to 12oC for water from wells in the southeastern 

part of the valley near the mountain front. The deepest 

well sampled as part of this study (well 25 is 1,212 ft 

deep) also had the warmest water (30.5oC).

Specific conductance ranged from 250 to 2,030 

μS/cm with a median value of 880 μS/cm. Generally, 

water from the northeastern and western part of the 

valley had a higher specific-conductance value than 

water from the central or southeastern part. Specific 

conductance for water from the 31 wells ranged from 

51 to 71 percent of the dissolved-solids concentration 

determined for residue remaining after evaporation of 

the sample at 180oC (mean and median value of 61 percent). The median pH value was 7.4; pH ranged from 

7.0 to 8.0, within the range established for secondary 

drinking-water regulations (6.5 to 8.5) (U.S. Environmental Protection Agency, 2002). Alkalinity varied 

from 84 to 302 mg/L with a median value of 174 mg/L. 

Table 6. Detection frequency and concentration of volatile organic compounds detected in water sampled from 31 public-supply wells in Salt Lake 

Valley, Utah, 2001

[Concentration reported in micrograms per liter; E, estimated value; —, not applicable or no applicable standard; M, presence of compound verified but not 

quantified; Maximum contaminant level is the U.S. Environmental Protection Agency established drinking-water standard (U.S. Environmental Protection 

Agency, 2002); Lifetime health advisory level is defined as the concentration of a chemical in drinking water that is not expected to cause any adverse 

noncarcinogenic effects for a lifetime of exposure (U.S. Environmental Protection Agency, 2002)]

Volatile organic compound Alternative name or 

abbreviation Predominant uses Number of detections

Laboratory 

reporting 

level

Maximum 

concentration

Mininum 

detected 

concentration

Maximum 

contaminant 

level

Lifetime 

health 

advisory

level

Bromodichloromethane Dichlorobromomethane Chlorination byproduct 11 0.05 5.4 E 0.02 180 —

Chloroform Trichloromethane Solvent, chlorination 

byproduct

17 .02 19.7 E .01 180 —

cis-1,2-Dichloroethylene cis-1,2-Dichloroethene Solvent, refrigerant 1 .04 E .03 — 70 70

Dibromochloromethane Chlorodibromomethane Chlorination byproduct 2 .2 1 0.4 180 —

Dichloromethane Methylene chloride Solvent, metal degreaser 2 .2 M M 5 —

Tetrachloroethylene Tetrachloroethene, PCE Solvent 3 .1 1 M 5 —

Tetrachloromethane Carbon tetrachloride Solvent, metal degreaser 2 .06 E .04 E .02 5 —

1,1,1-Trichloroethane Methyl chloroform, TCA Solvent 6 .03 E .05 E .01 200 200

Trichloroethylene Trichloroethene, TCE Solvent 2 .04 E .02 E .01 5 —

Trichlorofluoromethane Freon 11, CFC-11 Refrigerant, aerosol 

propellant

2 .09 .12 E .02 — 2,000

1,1,2-Trichlorotrifluoroethane CFC-113 Refrigerant, aerosol 

propellant

3 .06 .28 E .04 — —

1The maximum contaminant level for total trihalomethanes is 80 micrograms per liter.
18 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Dissolved-oxygen concentrations ranged from 

0.3 to 9.9 mg/L with a median value of 5.7 mg/L. The 

oxidation-reduction (redox) state of water can affect 

what constituents are present and at what concentrations. Dissolved-oxygen concentrations greater than an 

arbitrary level of 2.0 mg/L and no detectable concentrations of nitrite, ammonia, iron, or manganese generally 

indicate oxidizing conditions. Anomalously high dissolved-oxygen concentrations can result from aeration 

of ground water during pumping. Reducing conditions 

are indicated by relatively low concentrations of dissolved oxygen and nitrate and the presence of nitrite, 

ammonia, iron, or manganese. Reducing conditions 

occur at five of the public-supply wells sampled on the 

basis of dissolved oxygen concentrations less than 2.0 

mg/L. Four of the five wells are in the ground-water 

discharge area for the principal aquifer near the Jordan 

River. Low dissolved-oxygen concentrations are 

accompanied by the lowest nitrate concentrations and 

the highest ammonia, iron, and manganese concentrations in water sampled during the study (wells 9, 11, 

and 28). Water from well 1, which also is in this area, 

has slightly more dissolved oxygen (2.6 mg/L), possibly indicating mixing with oxygenated water. Water 

from wells 24 and 25, relatively deep wells on the west 

side of the valley, had a dissolved-oxygen concentration of 2.3 and 0.9 mg/L, respectively.

The highest dissolved-oxygen concentrations in 

ground water sampled for this study were measured in 

wells in or near the primary recharge area. Direct 

recharge of oxygenated water to the principal aquifer 

and the abundance of coarse-grained deposits that 

allow faster ground-water movement facilitate oxidizing conditions in the primary recharge areas of the valley.

Major Ions

Chemical composition of ground water largely 

depends on the type of rocks and associated minerals 

that it has contacted and how long the water has been in 

contact with the aquifer material. The most mineralized 

ground water sampled as part of this study was from 

the northwestern part of the valley where the dominant 

ions were sodium and chloride (fig. 6). The least mineralized water was from wells in the southeastern part 

where the nearby rock types are more resistant to 

weathering. Water from the southeastern part of the 

valley is predominantly a calcium-bicarbonate type. 

Water from the northeastern part of the valley contains 

more sulfate, likely from contact with Triassic-age 

shale and mudstone in the mountain block and in the 

basin-fill deposits in and near the area.

The distribution of dissolved-solids concentration (residue at 180oC) in water from the 31 wells 

ranged from 157 to 1,280 mg/L with a median concentration of 496 mg/L. The 15 public-supply wells that 

pumped the most water in the valley had the same 

range of dissolved-solids concentration, but the median 

concentration was 370 mg/L. Water from 8 wells on the 

west side of the valley had a median concentration of 

844 mg/L compared to 357 mg/L for water from 16 

wells on the east side and 370 mg/L for water from 7 

wells in the center of the valley near the Jordan River. 

Water pumped from wells on the west side of the valley 

generally is blended with water from other areas to 

reduce dissolved-solids concentrations.

Dissolved-solids concentration in ground water 

from the principal aquifer during 1988-92 (Thiros, 

1995) is shown in figure 7. This map was revised with 

data from the Utah Division of Drinking Water (written 

commun., 2002), Kennecott Utah Copper Corporation 

(written commun., 2002), and from this study to show 

the distribution of dissolved-solids concentration in 

water from the principal aquifer during 1998-2002 (fig. 

8). Most of the public-supply wells on the east side of 

the valley pump water with a dissolved-solids concentration of less than 500 mg/L, whereas only a few wells 

on the west side receive water with a dissolved-solids 

concentration of less than 500 mg/L. Water in the 

southeastern part of the aquifer generally contains less 

dissolved solids than the rest of the aquifer. Previous 

studies (Hely and others, 1971; Waddell and others, 

1987b; Lambert, 1995) indicate that recharge from the 

mountain block in this area moves rapidly through the 

coarse-grained deposits near the mountain front and 

has less time to react with the more resistant aquifer 

material. 

Comparison of water sampled during 1988-92 

and 1998-2002 shows a reduction in the area with a dissolved-solids concentration of less than 500 mg/L (figs. 

7 and 8). Ground water with a dissolved-solids concentration of less than 500 mg/L in an area extending to 

the northwest, past the Jordan River, receded back to 

the southeast likely because of pumping in the area and 

in upgradient areas to the southeast. Dissolved-solids 

concentration has increased in water from some wells 

located in the ground-water discharge area of the valley 

where the gradient has been upward between the 
Ground-Water Quality 19

Figure 6. Map showing Major-ion composition of water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001.

EXPLANATION

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Discharge area

Primary recharge area

Secondary recharge area

1

2

13 4

5

6

7

8

10 11

9

14

20

17

25

24

30

31

23

18

22

29

27 26

28

12

19

21

14

15

16

3

Approximate boundary of basin-fill deposits in Salt Lake Valley

Public-supply well sampled as part of this study—Number is well

identifier

1

2

13 4

5

6

7

8

10 11

9

14

20

17

25

24

30

31

23

18

22

29

27 26

28

12

19

21

15

16

3

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

Tailings ponds

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

DAVIS COUNTY

SALT LAKE COUNTY

UTAH COUNTY

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Cr

Cotton wood

Little

Cotton wood

Creek

Creek

12

13

14

15

16

17

18

19

20

23

14

15 5 10 15 10 5 0

Sodium + Potassium

Magnesium

Calcium

Chloride + Fluoride

Sulfate

Bicarbonate + Carbonate

2

4

6

8

10

11

9

7

3

5

1

22

21

28

26

24

29

27

25

30

31

MILLIEQUIVALENTS PER LITER
20 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 7. Map showing Dissolved-solids concentration in water sampled from the principal aquifer in Salt Lake Valley, Utah, 1988-92.

EXPLANATION

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Dissolved-solids concentration, in milligrams per liter, 1988–92 (Thiros, 1995)

Less than 250 250 to 500 500 to 1,000 1,000 to 2,000 2,000 to 5,000 Greater than 5,000

Boundary between secondary recharge area and discharge area

Boundary between primary and secondary recharge areas

Well used to determine the distribution of dissolved-solids

concentration in water from the principal aquifer, 1988–92

(Thiros, 1995)

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Approximate boundary of basin-fill deposits in Salt

Lake Valley

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
Ground-Water Quality 21

Figure 8. Map showing Dissolved-solids concentration in water sampled from the principal aquifer in Salt Lake Valley, Utah, 1998-2002.

EXPLANATION

Base from U.S. Geological Survey digital line graph data, 1:100,000 , 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Dissolved-solids concentration, in milligrams per liter, 1998–2002

Less than 250 250 to 500 500 to 1,000 1,000 to 2,000 2,000 to 5,000 Greater than 5,000

Boundary between secondary recharge area and discharge area

Boundary between primary and secondary recharge areas

Public-supply well used to determine the distribution of dissolvedsolids concentration in water from the principal aquifer during

1998–2002

Well greater than 300 feet deep with dissolved-solids concentration

data for 1998–2002 from Kennecott Utah Copper Corporation

(written commun., 2002)

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Boundary of area where the dissolved-solids concentration in

water from more than one well increased 20 percent or more

during 1988–2002

Approximate boundary of basin-fill deposits in Salt Lake Valley

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
22 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

principal aquifer and land surface. Ground-water 

withdrawals for public supply may have caused the 

water-level gradient to reverse, allowing more 

mineralized water to move from the shallow aquifer to 

the principal aquifer. The shallow aquifer in the area is 

recharged from the principal aquifer and from surfacewater sources such as the Jordan River. The possibility 

of water movement from the shallow aquifer to the 

principal aquifer is discussed in more detail in the 

“Sources of Ground-Water Recharge” section of this 

report.

Fewer wells are available on the west side of the 

valley that are completed in the principal aquifer. Water 

from some west-side wells increased in dissolvedsolids concentration from 1988-92 to 1998-2002, 

resulting in a reduction in the extent of less-than-500-

mg/L water on the west side of Salt Lake Valley.

Areas encompassing more than one well where 

the dissolved-solids concentration in water increased 

20 percent or more from 1988-92 to 1998-2002 also are 

shown in figure 8. Three distinct areas on the east side 

of the valley have undergone an increase in dissolvedsolids concentration: (1) west of the mouth of Big Cottonwood Canyon near the mountain front in the primary recharge area; (2) in part of the secondary 

recharge area near Sandy; and (3) in part of the discharge area near Murray. Ground-water withdrawals 

from wells may have caused the vertical or lateral gradients to change, which could allow water with a 

higher dissolved-solids concentration to reach the wells 

in these areas.

Trace Elements

Concentrations of the trace elements molybdenum, nickel, selenium, antimony, chromium, uranium, 

and barium, analyzed for in water from the publicsupply wells, were less than the MCLs or HALs (table 

4). Silver and beryllium were analyzed for, but not 

detected (table 15). Arsenic and radon were detected in 

water from some wells at concentrations that exceeded 

established or proposed MCLs. 

Dissolved arsenic concentrations ranged from 

0.4 to 17.9 μg/L (table 15) with a median of 1.1 μg/L in 

water from the 31 public-supply wells sampled as part 

of this study. Concentrations in water from five wells, 

four of which are on the west side of the valley, 

exceeded the drinking water MCL of 10 μg/L issued by 

the USEPA on January 22, 2001 (U.S. Environmental 

Protection Agency, 2001).

Data for wells accessed from the Utah Division 

of Drinking Water and other NAWQA studies were 

used to augment the data collected as part of this study 

and to show the distribution of arsenic in the principal 

aquifer in the valley (fig. 9). Water from wells in much 

of the western part of the valley generally had higher 

arsenic concentrations than other areas. This may be 

related to more arsenic-bearing minerals in the finegrained deposits in this area coupled with less recharge 

available to transport arsenic through the system. 

Dissolved-uranium concentration in water from 

the public-supply wells ranged from 0.04 to 15.1 μg/L 

with a median value of 3.10 μg/L. The MCL for uranium of 30 μg/L (U.S. Environmental Protection 

Agency, 2002) was not exceeded. Uranium is soluble 

under oxidizing conditions and because of its long half 

life (4.5x109 years) can be present in ground water farther from its source areas than can radon, which has a 

much shorter half life. Uranium is concentrated in the 

sediment in reducing environments as a result of mineral precipitation. The low uranium concentration in 

water from wells 9 and 28 in the discharge area (0.04 

and 0.08 μg/L, respectively) is related to reducing conditions. The relatively high uranium concentration in 

water from well 29 (15.1 μg/L) may result from its 

proximity to intrusive rocks in the Wasatch Range coupled with oxidizing conditions. 

Radon occurs naturally as a gas that is soluble in 

ground water and is released through radioactive decay 

from rocks containing uranium. It is the direct result of 

decay of radium-226, a decay product of uranium-238. 

Greater amounts of radon occur in areas with uraniumrich sources such as granite, some metamorphic rocks, 

and basin-fill deposits weathered from these rocks. 

Because of a short half-life of 3.8 days, radon generally 

is detected near its source. The amount of radon in 

water is reported in terms of activity where 1 pCi/L is 

about equal to the decay of two atoms of radon per 

minute in a liter of water. Radon moves more easily 

through highly permeable material, such as sand, 

gravel, and fractures, and readily degasses from water 

exposed to air. Breathing radon in indoor air is the 

second leading cause of lung cancer and is a greater 

health concern than drinking water that contains radon 

(U.S. Environmental Protection Agency, 1999). The 

USEPA’s proposed MCL for radon in drinking water is
Ground-Water Quality 23

Figure 9. Map showing Arsenic concentration in water sampled from the principal aquifer in Salt Lake Valley, Utah.

Approximate boundary of basin-fill deposits in Salt Lake Valley

Concentration of arsenic, in micrograms per liter—Wells completed

in principal aquifer

Data from NAWQA

analyses (dissolved)

0.1 to less than 1

1 to less than 5

5 to less than 10

10 to 20

Data from Utah Division

of Drinking Water (total)

Less than 1 5 to less than 10

Less than 5 10 to less than 20

0.1 to less than 1 20 to 26

1 to less than 5

EXPLANATION

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

Tailings ponds

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

DAVIS COUNTY

SALT LAKE COUNTY

UTAH COUNTY

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Discharge area

Primary recharge area

Secondary recharge area
24 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

300 pCi/L (U.S. Environmental Protection Agency, 

2002). The USEPA proposed rule for radon allows 

States and community-water systems to use an 

alternative standard of 4,000 pCi/L if they implement a 

program to address radon risks in indoor air.

Radon concentration in water from the 31 wells 

ranged from 251 to 1,980 pCi/L (fig. 10 and table 15), 

with a median value of 702 pCi/L. Water from wells in 

the discharge area near the Jordan River had the lowest 

radon concentrations because of distance from uranium-bearing rocks. The highest concentration was in 

water from well 13 near the mountain front south of 

Little Cottonwood Canyon where the mountain block is 

composed of quartzite and quartz monzonite.

Nutrient Constituents and Dissolved Organic 

Carbon

Although the nutrients nitrogen and phosphorus 

can occur naturally in ground water, elevated concentrations in ground water generally are thought to be 

caused by human activities. Some of the potential 

sources of nutrients in ground water include fertilizers 

applied to lawns and gardens and leaking or improperly 

functioning septic systems and sewer pipes. Nitrogen 

compounds such as ammonia and ammonium fertilizers naturally transform into nitrate, which is relatively 

stable in oxygenated subsurface environments and is 

readily transported in water. Nitrite is unstable in oxygenated water and is seldom present in measurable concentrations under oxidizing conditions. In this report, 

nitrate is reported as the sum of nitrite and nitrate as 

nitrogen. Nationally, background nitrate concentrations 

in ground water from areas not associated with agricultural practices commonly are less than 2 to 3 mg/L as 

nitrogen (Halberg and Keeney, 1993, p. 316), and concentrations greater than 2 mg/L may indicate effects of 

human activities (U.S. Geological Survey, 1999, p. 34). 

The national background concentration of nitrate was 

estimated on the basis of samples collected from undeveloped areas that are considered to be minimally 

affected by agriculture, urbanization, and associated 

land uses.

Nitrate concentration in water sampled from 12 

of the 31 public-supply wells (39 percent) was higher 

than the estimated background level of 2 mg/L, indicating a likely human influence. Concentrations ranged 

from less than 0.026 to 5.99 mg/L (fig. 11 and table 

16), less than the MCL of 10 mg/L (U.S. Environmental Protection Agency, 2002). The median nitrate concentration for water from public-supply wells on the 

east side of the valley was 1.21 mg/L compared to 3.12 

mg/L on the west side. 

Concentrations of nitrite, ammonia, ammonia 

plus organic nitrogen, phosphorus, and orthophosphorus in water from the public-supply wells were low, two 

to three orders of magnitude less than MCLs or HALs, 

where applicable. Ammonia concentrations greater 

than 0.1 mg/L were measured in water from three 

wells, all of which were under reducing conditions. 

Water from one well (well 28) had a phosphorus concentration greater than 0.1 mg/L (0.132 mg/L).

The presence of MBAS (methylene blue active 

substances) can be used as an indicator of contamination from wastewater because these substances generally are contained in soaps and detergents. MBAS 

concentrations in water samples from the public-supply 

wells were less than the reporting limit, except in water 

from two wells with concentrations of about 0.02 mg/L 

(wells 8 and 23) (table 16). The low MBAS concentrations coupled with nitrate concentrations above estimated background levels indicate that water from 

leaking sewer lines may possibly reach parts of the 

principal aquifer in the area of these wells.

DOC (dissolved organic carbon) can affect 

ground-water quality because it is involved in oxidation/reduction reactions with chemical constituents of 

the aquifer material and ground water. The median 

DOC concentration in water from the public-supply 

wells was less than 0.30 mg/L and ranged from less 

than 0.15 to 1.2 mg/L (tables 4 and 16).

Pesticides

Much lower analytical reporting levels were used 

in this study than are typically used in routine pesticide 

monitoring of public-water supplies. Therefore, higher 

rates of detection were obtained than would have been 

possible with less sensitive analytical methods. The 

MRL for atrazine is 0.007 μg/L, about two orders of 

magnitude lower than that used on water from drinking-water wells for the USEPA’s National Pesticide 

Survey done during 1988-90 (Barbash and others, 

1999, p. 8).

Four of the 103 pesticides and pesticide degradation products analyzed for (atrazine, deethylatrazine 

(DEA), deethyldeisopropylatrazine, and imazethapyr) 

were detected in 1 or more water samples collected as
Ground-Water Quality 25

Figure 10. Map showing Radon concentration in water sampled from the principal aquifer in Salt Lake Valley, Utah, 1998-2001.

EXPLANATION

Approximate boundary of basin-fill deposits in Salt Lake Valley

Concentration of radon, in picocuries per liter

Less than 500

500 to less than 750

750 to less than 1,000

1,000 to less than 1,500

1,500 to 1,980

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

Tailings ponds

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

DAVIS COUNTY

SALT LAKE COUNTY

UTAH COUNTY

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Discharge area

Primary recharge area

Secondary recharge area

Butterfield Creek

Creek Rose

Cr

Bingham

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
26 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 11. Map showing Nitrate concentration in water sampled from the principal aquifer in Salt Lake Valley, Utah, 1998-2001.

EXPLANATION

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill

deposits in Salt Lake Valley

Nitrate concentration, in milligrams per liter

Less than 0.05

0.05 to less than 1

1 to less than 3

3 to less than 5

5 to 7

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

Tailings ponds

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

DAVIS COUNTY

SALT LAKE COUNTY

UTAH COUNTY

Butterfield Creek

Creek Rose

Cr

Bingham

Coon

Creek

Parleys

Creek

City

Creek

Red

Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
Ground-Water Quality 27

part of this study (table 5, fig. 12). Degradation 

products of pesticides (metabolites or degradates) are 

formed through the metabolic breakdown of a parent 

compound. All of the pesticides analyzed for as part of 

this study are listed in table 7. At least 1 of the 4 

pesticides or pesticide degradation products was 

detected in water from 13 of the 31 wells sampled 

(table 17). None of the pesticide concentrations 

exceeded USEPA drinking-water standards or 

guidelines (U.S. Environmental Protection Agency, 

2002), although atrazine was the only compound 

detected that has an established standard.

The herbicide atrazine was detected in seven 

samples. Atrazine is a restricted-use pesticide that is 

generally used on corn and other row crops in agricultural areas and along roads, railroads, other rights-ofway, utility substations, and industrial lots to control 

weeds and undesired vegetation. It is not available for 

household use. Atrazine concentrations detected in 

water from the 31 wells sampled ranged from an estimated 0.002 to 0.034 μg/L (fig. 12), all less than the 

drinking-water MCL of 3 μg/L (U.S. Environmental 

Protection Agency, 2002). Atrazine was detected in 5 

of 8 wells sampled on the west side of the valley and in 

2 of 23 wells on the east side. The relatively high detection frequency of atrazine in water samples from the 

west side of Salt Lake Valley may be the result of its 

application in agricultural or industrial areas that may 

also be recharge areas. 

The degradation products of atrazine, deethylatrazine and deethyldeisopropylatrazine, were detected 

in 10 samples and 1 sample, respectively. The total 

concentration of atrazine and its degradation products 

in water samples from this study with detections 

ranged from an estimated 0.002 μg/L to 0.099 μg/L 

(figs. 12 and 13). The presence of atrazine and its degradation products in ground water is likely the result of 

widespread use rather than small-scale point sources

Figure 12. Graph showing Concentration of selected pesticides in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001.

Atrazine

Deethylatrazine

Deethyldeisopropylatrazine

Total atrazine

Imazethapyr

0.001

0.01

0.1

1

10

CONCENTRATION, IN MICROGRAMS PER LITER

Detection

Minimum reporting level

Maximum contaminant level
28 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table 7. Pesticides and degradation products analyzed for in water 

sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001—

Continued

Compound

Parameter 

code

Chemical 

Abstracts 

Service 

registry 

number

Minimum 

reporting 

level

Reporting 

level

type

Gas Chromatography/Mass Spectrometry analytical method

2,6-Diethylaniline 82660 579-66-8 0.002 LRL

Acetochlor 49260 34256-82-1 .004 LRL

Alachlor 46342 15972-60-8 .002 LRL

alpha-HCH 34253 319-84-6 .005 LRL

Atrazine 39632 1912-24-9 .007 LRL

Azinphos-methyl 82686 86-50-0 .050 LRL

Benfluralin 82673 1861-40-1 .010 LRL

Butylate 04028 2008-41-5 .002 MRL

Carbaryl 82680 63-25-2 .041 LRL

Carbofuran 82674 1563-66-2 .020 LRL

Chlorpyrifos 38933 2921-88-2 .005 LRL

cis-Permethrin 82687 54774-45-7 .006 LRL

Cyanazine 04041 21725-46-2 .018 LRL

Dacthal 82682 1861-32-1 .003 LRL

Deethylatrazine 04040 6190-65-4 .006 LRL

Diazinon 39572 333-41-5 .005 LRL

Dieldrin 39381 60-57-1 .005 LRL

Disulfoton 82677 298-04-4 .021 LRL

EPTC 82668 759-94-4 .002 LRL

Ethalfluralin 82663 55283-68-6 .009 LRL

Ethoprophos 82672 13194-48-4 .005 LRL

Fonofos 04095 944-22-9 .003 LRL

Lindane 39341 58-89-9 .004 LRL

Linuron 82666 330-55-2 .035 LRL

Malathion 39532 121-75-5 .027 LRL

Metolachlor 39415 51218-45-2 .013 LRL

Metribuzin 82630 21087-64-9 .006 LRL

Molinate 82671 2212-67-1 .002 LRL

Napropamide 82684 15299-99-7 .007 LRL

p,p’-DDE 34653 72-55-9 .003 LRL

Parathion 39542 56-38-2 .007 LRL

Parathion-methyl 82667 298-00-0 .006 LRL

Pebulate 82669 1114-71-2 .002 LRL

Pendimethalin 82683 40487-42-1 .010 LRL

Phorate 82664 298-02-2 .011 LRL

Prometon 04037 1610-18-0 .015 LRL

Propachlor 04024 1918-16-7 .010 LRL

Propanil 82679 709-98-8 .011 LRL

Propargite 82685 2312-35-8 .023 LRL

Propyzamide 82676 23950-58-5 .004 LRL

Simazine 04035 122-34-9 .011 LRL

Tebuthiuron 82670 34014-18-1 .016 LRL

Terbacil 82665 5902-51-2 .034 LRL

Terbufos 82675 13071-79-9 .017 LRL

Thiobencarb 82681 28249-77-6 .005 LRL

Gas Chromatography/Mass Spectrometry analytical method—

Continued

Triallate 82678 2303-17-5 .002 LRL

Trifluralin 82661 1582-09-8 .009 LRL

High-Performance Liquid Chromatography analytical method

2,4-D 39732 94-75-7 .02 MRL

2,4-D methyl ester 50470 1928-38-7 .009 MRL

2,4-DB 38746 94-82-6 .02 MRL

2-Hydroxyatrazine 50355 2163-68-0 .008 MRL

3(4-Chlorophenyl)-1-

methyl urea

61692 5352-88-5 .024 MRL

3-Hydroxycarbofuran 49308 16655-82-6 .01 MRL

3-Ketocarbofuran 50295 16709-30-1 1.50 MRL

Acifluorfen 49315 50594-66-6 .01 MRL

Aldicarb 49312 116-06-3 .04 MRL

Aldicarb sulfone 49313 1646-88-4 .02 MRL

Aldicarb sulfoxide 49314 1646-87-3 .01 MRL

Atrazine 39632 1912-24-9 .009 MRL

Bendiocarb 50299 22781-23-3 .025 MRL

Benomyl 50300 17804-35-2 .004 MRL

Bensulfuron-methyl 61693 83055-99-6 .016 MRL

Bentazon 38711 25057-89-0 .01 MRL

Bromacil 04029 314-40-9 .03 MRL

Bromoxynil 49311 1689-84-5 .02 MRL

Caffeine 50305 58-08-2 .010 MRL

Carbaryl 49310 63-25-2 .03 MRL

Carbofuran 49309 1563-66-2 .01 MRL

Chloramben methyl ester 61188 7286-84-2 .02 MRL

Chlorimuron-ethyl 50306 90982-32-4 .010 MRL

Chlorothalonil 49306 1897-45-6 .04 MRL

Clopyralid 49305 1702-17-6 .01 MRL

Cycloate 04031 1134-23-2 .01 MRL

Dacthal monoacid 49304 887-54-7 .01 MRL

Deethylatrazine 04040 6190-65-4 .03 MRL

Deethyldeisopropylatrazine 04039 3397-62-4 .01 MRL

Deisopropylatrazine 04038 1007-28-9 .04 MRL

Dicamba 38442 1918-00-9 .01 MRL

Dichlorprop 49302 120-36-5 .01 MRL

Dinoseb 49301 88-85-7 .01 MRL

Diphenamid 04033 957-51-7 .03 MRL

Diuron 49300 330-54-1 .01 MRL

Fenuron 49297 101-42-8 .03 MRL

Flumetsulam 61694 98967-40-9 .011 MRL

Fluometuron 38811 2164-17-2 .03 MRL

Imazaquin 50356 81335-37-7 .016 MRL

Imazethapyr 50407 81335-77-5 .017 MRL

Table 7. Pesticides and degradation products analyzed for in water 

sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001—

Continued

Compound

Parameter 

code

Chemical 

Abstracts 

Service 

registry 

number

Minimum 

reporting 

level

Reporting 

level

type

Table 7. Pesticides and degradation products analyzed for in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

[Parameter code is used in U.S. Geological Survey National Water Information System database; minimum reporting level in micrograms per liter; LRL, 

laboratory reporting level; MRL, minimum reporting level; —, registry number not available]
Ground-Water Quality 29

such as spills, although it probably is transported to the 

ground-water system by more direct sources of 

recharge, such as seepage from drainage systems and 

retention basins. Imazethapyr, an herbicide used to 

control grasses and broadleaf weeds, was detected at 

very low concentrations in water sampled from two 

wells (fig. 12 and table 17).

Volatile Organic Compounds

VOCs are carbon-containing chemicals that 

readily evaporate at normal air temperature and pressure. They are contained in many manufactured products such as gasoline, paints, adhesives, solvents, wood 

preservatives, dry cleaning agents, pesticides, fertilizers, cosmetics, and refrigerants. Potential sources of 

VOCs to ground water are direct industrial and wastewater discharges, infiltration of spills, leaking underground storage tanks, runoff to storm drains, septic 

systems, leaking sewer lines, and atmospheric deposition of vehicle and industrial emissions. The U.S. Environmental Protection Agency (2002) has established 

MCLs in drinking water for more than 20 VOCs 

because of human health concerns.

Eleven of the 85 VOCs analyzed for were 

detected in one or more of the water samples collected 

from the 31 public-supply wells (table 6, fig. 14, and 

table 18). All of the VOCs analyzed for as part of this 

study are listed in table 8. Detection of many VOCs is 

the result of improved analytical methods that allow 

measurement of lower concentrations (Conner and others, 1998). The most frequently detected VOCs were 

chloroform (54.8 percent), bromodichloromethane 

(35.5 percent), and 1,1,1-trichloroethane (19.4 percent). 

Chloroform and bromodichloromethane are 

byproducts of chlorinated ground and surface water 

that has reacted with organic material in the water and 

aquifer material and are part of a group of VOCs 

known as trihalomethanes (THMs). These disinfection 

byproducts are regulated by the USEPA as total THMs 

with a cumulative MCL of 80 μg/L (U.S. Environmental Protection Agency, 2002, p. 2). The MCL primarily 

applies to water sampled from distribution lines and at 

taps after being chlorinated. Widespread occurrence of 

chloroform and bromodichloromethane in ground 

water is likely a result of the recharge of chlorinated 

public-supply water used to irrigate lawns and gardens 

in residential areas of Salt Lake Valley. Water disinfected for public supply also can enter the groundwater system through leaking water lines, sewer lines, 

and swimming pools.

Chloroform and bromodichloromethane were 

detected together in water from 11 wells and neither 

was detected in water from 14 wells. The median chloroform concentration in water from the 31 publicsupply wells was less than 0.02 μg/L, whereas the 

median concentration in 17 samples with detections 

was 0.37 μg/L. Total THM (chloroform, bromodichloromethane, and chlorodibromomethane) concentration 

in samples with detections ranged from an estimated 

0.01 μg/L to 26.1 μg/L, less than the MCL. Wells 8 and 

13, in and near the primary recharge area on the east 

side of the valley, had the highest THM concentrations 

(14.4 and 26.1 μg/L, respectively) because they also 

High-Performance Liquid Chromatography analytical method—

Continued

Imidacloprid 61695 138261-41-3 .007 MRL

Linuron 38478 330-55-2 .01 MRL

MCPA 38482 94-74-6 .02 MRL

MCPB 38487 94-81-5 .01 MRL

Metalaxyl 50359 57837-19-1 .020 MRL

Methiocarb 38501 2032-65-7 .01 MRL

Methomyl 49296 16752-77-5 .004 MRL

Methomyl oxime 61696 13749-94-5 .011 MRL

Metsulfuron methyl 61697 74223-64-6 .025 MRL

Neburon 49294 555-37-3 .01 MRL

Nicosulfuron 50364 111991-09-4 .013 MRL

Norflurazon 49293 27314-13-2 .02 MRL

Oryzalin 49292 19044-88-3 .02 MRL

Oxamyl 38866 23135-22-0 .01 MRL

Oxamyl oxime 50410 30558-43-1 .013 MRL

Picloram 49291 — .02 MRL

Propham 49236 122-42-9 .01 MRL

Propiconazole 50471 60207-90-1 .021 MRL

Propoxur 38538 114-26-1 .01 MRL

Siduron 38548 1982-49-6 .017 MRL

Sulfometuron-methyl 50337 74222-97-2 .009 MRL

Tebuthiuron 82670 34014-18-1 .006 MRL

Terbacil 04032 5902-51-2 .01 MRL

Tribenuron-methyl 61159 101200-48-0 .01 MRL

Triclopyr 49235 55335-06-3 .02 MRL

Table 7. Pesticides and degradation products analyzed for in water 

sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001—

Continued

Compound

Parameter 

code

Chemical 

Abstracts 

Service 

registry 

number

Minimum 

reporting 

level

Reporting 

level

type
30 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 13. Map showing Total concentration of atrazine and its degradation products in water sampled from the principal aquifer in Salt Lake Valley, 

Utah, 1998-2001.

EXPLANATION

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in

Salt Lake Valley

Total concentration of atrazine and its degradation products,

in micrograms per liter

Not detected

0.002 to less than 0.01

0.01 to less than 0.1

0.1 to 1.0

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

Tailings ponds

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

DAVIS COUNTY

SALT LAKE COUNTY

UTAH COUNTY

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
Ground-Water Quality 31

inject chlorinated surface water into the aquifer during 

parts of the year. Chloroform concentration in these 

wells is greater than 10 μg/L (fig. 15). This water is 

stored in the aquifer and the wells are used to withdraw 

water during peak water-use periods.

1,1,1-trichloroethane (methyl chloroform, TCA) 

was detected in water from six wells at estimated concentrations ranging from 0.01 μg/L to 0.05 μg/L. It is 

generally used as a solvent and has an MCL of 200 

μg/L. 1,1,1-trichloroethane was detected with other 

VOCs in samples from five of the public-supply wells 

and in shallow ground water in Salt Lake Valley (Thiros, 2003), indicating movement from land surface or 

the shallow aquifer. It was the only VOC detected in 

the water sample from well 1 in the discharge area, 

where VOCs were not detected in water from other 

sampled wells. Pumping in the area may have reversed 

the water-level gradient around the well, allowing shallow ground water to move to the principal aquifer.

Tetrachloroethylene (tetrachloroethene, perchloroethylene (PCE)), primarily used as a dry cleaning 

agent, was detected in water from three wells with a 

maximum concentration of 1 μg/L. The MCL for PCE 

in drinking water is 5 μg/L (U.S. Environmental Protection Agency, 2002). Trichloroethylene (trichloroethene (TCE)), also used as a dry cleaning agent and 

solvent, was detected in two of the water samples that 

contained PCE (wells 4 and 17). TCE can be formed 

from the degradation of PCE by bacteria under reducing conditions.

Figure 14. Graph showing Concentration of selected volatile organic compounds in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 

2001.

CONCENTRATION, IN MICROGRAMS PER LITER

Detection

Laboratory reporting level

Maximum contaminant level

CFC-113

CFC-11

Trichloroethylene

1,1,1-Trichloroethane

Tetrachloroethylene

Tetrachloromethane

Dichloromethane

cis-1,2-Dichloroethylene

Total trihalomethanes

Dibromochloromethane

Chloroform

Bromodichloromethane

0.01

0.1

1

10

100
32 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Compound 

Parameter 

code

Chemical 

Abstracts 

Service 

registry 

number

Laboratory 

reporting

level

1,1,1,2-Tetrachloroethane 77562 630-20-6 0.03

1,1,1-Trichloroethane 34506 71-55-6 .03

1,1,2,2-Tetrachloroethane 34516 79-34-5 .09

1,1,2-Trichloroethane 34511 79-00-5 .06

1,1,2-Trichlorotrifluoroethane 77652 76-13-1 .06

1,1-Dichloroethane 34496 75-34-3 .04

1,1-Dichloroethylene 34501 75-35-4 .04

1,1-Dichloropropene 77168 563-58-6 .03

1,2,3,4-Tetramethylbenzene 49999 488-23-3 .2

1,2,3,5-Tetramethylbenzene 50000 527-53-7 .2

1,2,3-Trichlorobenzene 77613 87-61-6 .3

1,2,3-Trichloropropane 77443 96-18-4 .2

1,2,3-Trimethylbenzene 77221 526-73-8 .1

1,2,4-Trichlorobenzene 34551 120-82-1 .2

1,2,4-Trimethylbenzene 77222 95-63-6 .06

1,2-Dibromo-3-chloropropane 82625 96-12-8 .2

1,2-Dibromoethane 77651 106-93-4 .04

1,2-Dichlorobenzene 34536 95-50-1 .03

1,2-Dichloroethane 32103 107-06-2 .1

1,2-Dichloropropane 34541 78-87-5 .03

1,3,5-Trimethylbenzene 77226 108-67-8 .04

1,3-Dichlorobenzene 34566 541-73-1 .03

1,3-Dichloropropane 77173 142-28-9 .1

1,4-Dichlorobenzene 34571 106-46-7 .05

2,2-Dichloropropane 77170 594-20-7 .05

2-Butanone 81595 78-93-3 2

2-Chlorotoluene 77275 95-49-8 .03

2-Hexanone 77103 591-78-6 .7

3-Chloropropene 78109 107-05-1 .1

4-Chlorotoluene 77277 106-43-4 .06

4-Isopropyl-1-methylbenzene 77356 99-87-6 .07

4-Methyl-2-pentanone 78133 108-10-1 .4

Acetone 81552 67-64-1 7

Acrylonitrile 34215 107-13-1 1

Benzene 34030 71-43-2 .04

Bromobenzene 81555 108-86-1 .04

Bromochloromethane 77297 74-97-5 .04

Bromodichloromethane 32101 75-27-4 .05

Bromoform 32104 75-25-2 .06

Bromomethane 34413 74-83-9 .3

Butylbenzene 77342 104-51-8 .2

Carbon disulfide 77041 75-15-0 .07

Chlorobenzene 34301 108-90-7 .03

Chloroethane 34311 75-00-3 .1

Chloroform 32106 67-66-3 .02

Chloromethane 34418 74-87-3 .2

Dibromochloromethane 32105 124-48-1 .2

Dibromomethane 30217 74-95-3 .05

Dichlorodifluoromethane 34668 75-71-8 .3

Dichloromethane 34423 75-09-2 .2

Diethyl ether 81576 60-29-7 .2

Diisopropyl ether 81577 108-20-3 .1

Ethyl methacrylate 73570 97-63-2 .2

Ethyl tert-butyl ether 50004 637-92-3 .05

Ethylbenzene 34371 100-41-4 .03

Hexachlorobutadiene 39702 87-68-3 .1

Hexachloroethane 34396 67-72-1 .2

Isopropylbenzene 77223 98-82-8 .03

Methyl acrylate 49991 96-33-3 1

Methyl acrylonitrile 81593 126-98-7 .6

Methyl iodide 77424 74-88-4 .1

Methyl methacrylate 81597 80-62-6 .3

Naphthalene 34696 91-20-3 .2

Styrene 77128 100-42-5 .04

Tetrachloroethylene 34475 127-18-4 .1

Tetrachloromethane 32102 56-23-5 .06

Tetrahydrofuran 81607 109-99-9 2

Toluene 34010 108-88-3 .05

Trichloroethylene 39180 79-01-6 .04

Trichlorofluoromethane 34488 75-69-4 .09

Vinyl bromide 50002 593-60-2 .1

Vinyl chloride 39175 75-01-4 .1

cis-1,2-Dichloroethylene 77093 156-59-2 .04

cis-1,3-Dichloropropene 34704 10061-01-5 .09

m- and p-Xylene 85795 — .06

n-Propylbenzene 77224 103-65-1 .04

o-Ethyl toluene 77220 611-14-3 .06

o-Xylene 77135 95-47-6 .04

sec-Butylbenzene 77350 135-98-8 .03

tert-Butyl methyl ether 78032 1634-04-4 .2

tert-Butylbenzene 77353 98-06-6 .06

tert-Pentyl methyl ether 50005 994-05-8 .1

trans-1,2-Dichloroethylene 34546 156-60-5 .03

trans-1,3-Dichloropropene 34699 10061-02-6 .09

trans-1,4-Dichloro-2-butene 73547 110-57-6 .7

Compound 

Parameter 

code

Chemical 

Abstracts 

Service 

registry 

number

Laboratory 

reporting

level

Table 8. Volatile organic compounds analyzed for in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

[Parameter code is used in U.S. Geological Survey National Water Information System database; Laboratory reporting level in micrograms per liter; —, 

registry number not available] 
Ground-Water Quality 33

Figure 15. Map showing Chloroform concentration in water sampled from the principal aquifer in Salt Lake Valley, Utah, 1998-2001.

EXPLANATION

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in

Salt Lake Valley

Chloroform concentration, in micrograms per liter

Not detected, less than 0.02

Not detected, less than 0.05

0.01 to less than 0.1

0.1 to less than 1.0

1.0 to less than 10

10 to 20

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

Tailings ponds

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

DAVIS COUNTY

SALT LAKE COUNTY

UTAH COUNTY

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
34 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Leaking underground storage tanks commonly 

are a source of shallow ground-water contamination 

from the VOCs benzene, toluene, ethylbenzene, and 

xylene (BTEX). These gasoline-derived compounds 

were not detected in the water samples from the publicsupply wells in Salt Lake Valley, except for a trace 

amount of benzene in water from well 25. This well is 

more than 1,200 ft deep, and environmental-tracer data 

indicate that the water was recharged prior to the 

1950s. Therefore, the benzene detected in water from 

well 25 may be a result of contamination during sampling. Natural attenuation likely removes most of the 

BTEX compounds before they reach the principal aquifer.

SOURCES OF GROUND-WATER RECHARGE

Environmental tracers were used to determine 

the sources of recharge to the principal aquifer. The 

stable isotopes of water (deuterium and oxygen-18) and 

recharge temperatures computed from dissolved noble 

gases in the ground water were used to differentiate 

between water that enters the ground-water system in 

the valley (valley recharge) and subsurface inflow from 

the adjacent mountains (mountain-block recharge). Tritium, 3He, and CFCs were used to identify and date 

ground water recharged within the past 50 years. The 

location of wells completed in the principal aquifer 

where environmental-tracer data has been collected is 

shown on figure 16.

The majority of the local population resides in 

Salt Lake Valley, along with most of the local industry. 

Valley recharge therefore has a higher likelihood of 

containing man-made chemical compounds that are 

potentially harmful to human health than does mountain-block recharge. Occurrence of such compounds in 

the shallow aquifer, which receives valley recharge, at 

levels exceeding USEPA drinking-water standards is 

well documented (Thiros, 2003; Seiler and Waddell, 

1984). Wells with a larger component of valley 

recharge should have a greater susceptibility to effects 

from water containing these compounds (henceforth 

“susceptibility”) than wells that primarily receive 

mountain-block recharge.

Production and use of industrial chemicals 

increased substantially in the latter half of the 20th century. Wells that receive dominantly pre-1950s recharge 

should, therefore, have less susceptibility than those 

receiving dominantly younger recharge, at least in the 

near future.

Stable Isotopes

Deuterium (D or 2H) and oxygen-18 (18O) are 

stable isotopes of hydrogen and oxygen naturally 

incorporated into water molecules in small quantities. 

Water molecules with an 18O or a 2H atom are heavier 

than typical water molecules, which consist of 16O and 

1H atoms. This mass difference causes the heavier 

water molecules to behave differently from typical 

water molecules during evaporation and condensation, 

often resulting in different sources of ground-water 

recharge having different isotopic signatures. Because 

18O and 2H generally are conservative in shallow 

ground-water systems, stable isotope measurements 

can reveal information about the relative contributions 

of different recharge sources. Oxygen-18 and 2H concentrations, expressed as delta (δ) 18O and 2H, are 

reported in parts per thousand (‰, per mil) deviation 

from a reference standard called Vienna Standard Mean 

Ocean Water (VSMOW). Water with lower (typically 

more negative) 18O or 2H values is lighter, having less 

18O and 2H relative to 16O and 1H, respectively.

As discussed in the “Ground-Water Hydrology” 

section of this report, major sources of recharge to the 

principal aquifer include mountain-block recharge 

(MBR), stream loss, canal loss, and infiltration of 

valley precipitation and unconsumed irrigation water. 

Stable-isotope data from previous studies define the 

general isotopic signatures of these different sources. 

The following discussion covers 18O data only, but 2H 

data follow similar trends and provide similar insights 

into recharge to the principal aquifer.

Delta 18O values for MBR should be similar to 

those of mountain springs and mine-tunnel discharge 

waters. Delta 18O values for 21 samples collected from 

springs and mines located on the western slope of the 

Wasatch Range adjacent to Salt Lake Valley vary from 

-15.5 to -18.0 per mil (Mayo and Loucks, 1995, table 3; 

Parry and others, 2000, table 2; Thiros, 1995, pl. 1). 

One exception is a sample from an anomalously warm 

(22°C) spring in Parleys Canyon with a measured 18O 

value of -13.6 per mil (Mayo and Loucks, 1995, table 

3). However, this sample is clearly an outlier and is 

therefore not considered to be generally representative 

of MBR. Because gaining streams at base flow 
Sources of Ground-Water Recharge 35

Figure 16. Map showing Wells with delta oxygen-18, dissolved-gas, recharge-temperature, and (or) tritium/helium-3 age data for water sampled from 

the principal aquifer in Salt Lake Valley, Utah, 1990-2001.

81 72

92

96

79

68

75

90

89

93

69

97 83

86

76

94

80

77 85

73

84

78

88

87

71

82

95

91

74

70

EXPLANATION

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Boundary between secondary recharge area and discharge area

Boundary between primary and secondary recharge areas

Approximate boundary of basin-fill deposits in Salt Lake Valley

Well completed in principal aquifer—Number is well identifier

listed in tables 9, 10, and (or) 11

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

44

21

20

32

50

19

18

67

30

55

28

14 10

16

17

66

11

3

31

35

52 61 62

1

27

42

24

26

57

33

15

58

2 12

43

51

23

6

49

37

4

59

41

5

34

13 39

47

46

8

45

40

38

29

60

54

48

22

7

65

64

56

63

9

25

53

55

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek

36
36 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

effectively serve as ground-water integrators, 

mountain-stream samples collected near the mountain 

front at base flow conditions should provide an 

approximate average 18O value for MBR. Delta 18O 

values for five samples collected at or near base flow 

from streams entering Salt Lake Valley range from 

-16.0 to -17.2 per mil, with a mean of -16.5 per mil 

(Thiros, 1995, table 6). This mean value is only 

slightly heavier than that of the mountain spring and 

mine-tunnel samples (-16.8 per mil).

Stream loss should be represented by stream 

samples collected near the mountain front during both 

base flow and spring runoff. Delta 18O values for nine 

such samples collected from Wasatch Range streams 

on the east side of the valley (Red Butte Creek, Mill 

Creek, Big Cottonwood Creek, and Little Cottonwood 

Creek) also range from -16.0 to -17.2 per mil (Thiros, 

1995, table 6), but with a mean of -16.6 per mil. Thiros 

(1995, table 6) reports two stream samples collected 

part way up Butterfield Creek in the Oquirrh Mountains with 18O values of -16.0 and -16.5 per mil (spring 

runoff and base flow, respectively). The similarity 

among these values and those from Wasatch Range 

streams indicates that stream loss on the west side of 

the valley has an isotopic signature similar to stream 

loss on the east side. Existing isotope data from 

streams, springs, and mine tunnels therefore indicate 

that mountain-front recharge (MFR, consisting of 

MBR and stream loss combined) to the valley has a 

mean 18O value of about -16.6 per mil.

Thiros (2003, table 5) presents δ18O values for 

water samples collected from shallow monitoring wells 

(generally screened less than about 15 ft below the 

water table) in the secondary recharge areas of Salt 

Lake Valley. These wells were installed and sampled to 

study the effects of residential land use on shallow 

ground-water quality. Three of the shallow wells are 

located near Little Cottonwood Creek and appear to be 

hydraulically connected to the stream on the basis of 

temperature and water-level data. Water from these 

wells has δ18O values between -16.0 and -16.5 per mil, 

similar to stream values. The 26 other shallow monitoring wells are a considerable distance from mountain-front streams, and their water should therefore 

have δ18O values representative of recharge sources 

other than MFR, including canal loss and seepage from 

valley precipitation and unconsumed irrigation water. 

Delta 18O values for water from these wells range from 

-10.8 to -15.0 per mil. Shallow ground water located 

upgradient from canals diverted from the Jordan River 

should not be recharged by canal water. Delta 18O 

values for water from the seven shallow wells upgradient from canals are from -14.3 to -15.0 per mil, with a 

mean of -14.7 per mil. Delta 18O values for water samples from the Jordan River and its diversion canals are 

considerably heavier as a result of evaporation, predominantly ranging from about -9 to -14 per mil (Thiros, 1995, table 6; and Thiros, 2003, table 5).

Delta 18O and 2H values for water from 67 wells 

screened in the principal aquifer in Salt Lake Valley are 

listed in table 9. The distribution of these data is shown 

in figure 17. These 67 wells include the 31 publicsupply wells sampled as part of this study; 20 wells 

sampled by NAWQA during 1998-2000 as part of other 

studies; and 16 other wells sampled during 1990-91, 

the results from which are listed in Thiros (1995, table 

7). The range of δ18O values (-10.6 to -17.4 per mil) in 

water from wells screened in the principal aquifer is 

similar to that of the recharge sources. Water from 

most of the wells has δ18O values of less than or equal 

to -14.7 per mil, indicating that MFR to the principal 

aquifer is substantial. Interpretation of this combined 

data set indicates that δ18O values generally are lighter 

on the east side of the valley than on the west side, indicating that MFR is greater on the east side than on the 

west side. The δ18O value of -17.4 per mil and temperature of 30.5oC for water from well 25 sampled as part 

of this study is anomalous for the west side of the valley, probably because of the greater depth of the well. 

Therefore, the stable isotope data generally corroborate 

the existing conceptual model of ground-water flow in 

the principal aquifer (see “Ground-Water Hydrology” 

section of this report).

The approximate fraction of MFR in the principal aquifer can be computed from the δ18O values by 

assuming two-component mixing between MFR and 

non-MFR sources. An approximate minimum MFR 

fraction was calculated for each well listed in table 9 by 

assuming that the non-MFR component is free of evaporated canal water (table 9 and fig. 18). The MFR and 

non-MFR components were thus assumed to have 

mean δ18O values of -16.6 and -14.7 per mil, respectively. Minimum MFR fractions are dominantly 

greater than 0.5 on the east side of the valley, indicating 

that MFR constitutes most of the recharge to the eastern part of the principal aquifer. In contrast, minimum 

MFR fractions are dominantly less than 0.2 on the west 

side of the valley, indicating that most of the recharge 

in this area consists of non-MFR sources. MFR fractions are generally the highest (consistently greater
Sources of Ground-Water Recharge 37

Well 

identifier 

(fig. 16)

Sample date δ2H

(per mil)

δ180

(per mil)

Mountainfront 

recharge 

fraction

1 05/15/2001 -116.6 -15.47 0.41

2 05/10/2001 -120.5 -16.30 .84

3 05/15/2001 -124.2 -16.77 1.0

4 11/26/1991 -119.0 -16.00 .68

4 05/09/2001 -117.9 -16.02 .69

5 05/30/2001 -122.8 -16.37 .88

6 06/05/2001 -123.1 -16.15 .76

7 05/08/2001 -114.7 -14.84 .07

8 06/25/2001 -116.2 -15.66 .51

9 05/16/2001 -125.0 -16.95 1.0

10 05/02/2001 -96.5 -11.48 0

11 06/06/2001 -126.6 -16.89 1.0

12 05/14/2001 -117.9 -16.14 .76

13 06/20/1991 -120.0 -16.20 .79

13 06/12/2001 -118.0 -15.97 .67

14 05/03/2001 -92.9 -10.65 0

15 06/13/2001 -117.2 -15.78 .57

16 06/25/2001 -120.8 -15.80 .58

17 05/29/2001 -121.0 -15.82 .59

18 05/24/2001 -125.6 -16.64 1.0

19 05/23/2001 -123.1 -16.66 1.0

20 06/20/1991 -109.0 -13.90 0

20 05/14/2001 -112.8 -15.00 .16

21 06/07/2001 -115.6 -15.22 .27

22 05/22/2001 -111.2 -14.52 0

23 06/26/2001 -118.6 -14.92 .12

24 05/01/2001 -117.0 -14.97 .14

25 05/21/2001 -132.3 1-17.38 1.0

26 05/23/2001 -120.6 -16.44 .92

27 06/11/2001 -119.3 -15.96 .66

28 05/16/2001 -122.7 -16.39 .89

29 05/07/2001 -120.4 -16.19 .78

30 06/05/2001 -121.1 -15.91 .64

31 06/12/2001 -114.2 -15.09 .21

32 06/20/1991 -122.0 -16.45 .92

33 06/21/1991 -120.0 -16.25 .82

34 09/18/1990 -122.0 -16.50 .95

35 05/31/1991 -120.0 -16.15 .76

36 09/18/1990 -121.0 -16.10 .74

36 06/20/1991 -119.0 -16.00 .68

37 10/22/1991 -119.0 -15.95 .66

38 06/25/1991 -120.0 -15.85 .61

39 05/31/1991 -119.0 -15.75 .55

40 09/30/1991 -118.0 -15.75 .55

41 05/31/1991 -119.0 -15.70 .53

42 12/23/1991 -115.0 -15.15 .24

43 09/17/1990 -123.0 -16.40 .89

43 07/13/2000 -123.0 -16.47 .93

44 09/17/1990 -118.0 -16.20 .79

45 09/17/1990 -118.0 -15.90 .63

46 06/20/1991 -118.0 -15.85 .61

47 09/17/1990 -124.0 -15.80 .58

48 08/13/1998 -121.0 -15.70 .53

49 07/29/1998 -118.7 -15.54 .44

50 08/05/1998 -117.0 -15.54 .44

51 10/29/1998 -120.6 -15.33 .33

52 09/01/1998 -117.1 -14.82 .06

53 07/28/1998 -115.4 -14.50 0

54 08/12/1998 -111.1 -14.31 0

55 09/10/1998 -114.6 -14.28 0

56 08/31/1998 -100.5 -12.57 0

57 10/07/1998 -121.7 -16.44 .92

58 09/22/1998 -119.3 -15.96 .66

59 08/10/2000 -119.1 -15.87 .62

60 09/21/1998 -117.9 -15.24 .28

61 08/18/1998 -114.4 -14.39 0

62 06/07/2000 -110.7 -13.93 0

63 09/16/1998 -110.6 -13.90 0

64 09/28/1998 -108.4 -13.34 0

65 10/14/1998 -102.3 -12.45 0

66 11/10/1998 -121.8 -15.92 .64

67 11/14/1990 -122.0 -16.20 .79

1 The δ18O value is not shown on figure 17.

Well 

identifier 

(fig. 16)

Sample date δ2H

(per mil)

δ180

(per mil)

Mountainfront 

recharge 

fraction

Table 9. Stable-isotope data for water sampled from the principal aquifer in Salt Lake Valley, Utah, 1990-2001

[δ2H: delta deuterium value; δ18O: delta oxygen-18 value; boxed samples were collected from the same well]
38 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 17. Map showing Delta oxygen-18 values for water sampled from the principal aquifer in Salt Lake Valley, Utah, 1990-2001.

EXPLANATION

Delta oxygen-18 values, in per mil

-17.0 to -16.5 -16.5 to -16.0 -16.0 to -15.5 -15.5 to -15.0 -15.0 to -14.0

-14.0 to -13.0 -13.0 to -12.0 -12.0 to -11.0 -11.0 to -10.0

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Boundary between secondary recharge area and discharge area

Boundary between primary and secondary recharge areas

Approximate boundary of basin-fill deposits in Salt Lake Valley

Well completed in principal aquifer—Number is delta oxygen-18

value

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

UTAH COUNTY

-16.20

-15.22

-15.00

-16.45

-15.54 -16.66

-16.64

-16.20

-15.91

-14.52

-16.39

-10.65 -11.48

-15.80

-15.82

-15.92

-16.89

-16.77

-15.09

-16.15

-14.82 -14.39

-13.93

-15.47

-15.96

-15.15

-14.97

-16.44

-16.44

-16.25

-15.78

-15.96

-16.30

-16.14

-16.47

-15.33

-14.92

-16.15

-15.54

-15.95

-16.02 -15.87

-15.70

-16.37

-16.50

-15.97 -15.75

-15.80

-15.85 -15.66

-15.90 -15.75

-15.85

-16.19

-15.70

-14.31

-15.24 -14.52

-14.84 -12.45

-13.34

-12.57

-13.90

-14.50

-16.95

-16.00

-14.28

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
Sources of Ground-Water Recharge 39

Figure 18. Map showing Distribution of minimum mountain-front recharge fractions for water sampled from the principal aquifer in Salt Lake Valley, 

Utah, 1990-2001.

EXPLANATION

Mountain-front recharge fraction

Less than 0.25 0.25 to 0.50 0.50 to 0.75 0.75 to 1.0 1.0

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Boundary of zone of principal aquifer referred to in text

0.61

Boundary between secondary recharge area and discharge area

Boundary between primary and secondary recharge areas

Approximate boundary of basin-fill deposits in Salt Lake Valley

Well completed in principal aquifer—Number is minimum mountainfront recharge fraction

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

UTAH COUNTY

0.63

0.55

0.79 0.51 0.58

0.67

0.76

0.66 0.88

0.27

0.16

0.92

0.92

0.44

0.82

1.0

1.0

1.0

0.59

0.64

0

0.58

0.64

0.79

0.89

0.76

1.0

1.0

0.21

0.41

0.66

0.92

0.66

0.57 0.84 0.93

0.24

0.95 0.53

0.69 0.62

0.55

0.74

0.61

0.78

0

1.0

0 0

0.14

0.33

0.12

0.76

0.44

0.53

0

0.28

0.07

0

0

0

Parleys zone

Murray zone

Midvale zone

Sandy zone

0

0

0.06

0 0

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

0

Creek
40 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

than 0.9) in the Parleys zone on the east side of the 

valley. Delta 18O values are well above -14.7 per mil in 

the northwestern part of the valley (-11.5 and -10.7 per 

mil in wells 10 and 14, respectively, table 9), indicating 

that canal water is the primary source of recharge in 

this area.

The minimum MFR fraction may be an important indicator of well susceptibility. Wells with lower 

minimum MFR fractions probably receive more valley 

recharge than wells with higher minimum MFR fractions. The lower minimum MFR fractions observed on 

the west side of the valley indicate that west-side wells 

generally are more susceptible than east-side wells. A 

few wells on the east side of the valley have water with 

anomalously low minimum MFR fractions (less than 

0.5) relative to other east-side wells, indicating that 

these too have a higher level of susceptibility.

Dissolved Gas Recharge Temperatures

Recharge temperature (Tr) is the temperature at 

which gas exchange between recharging ground water 

and the atmosphere last occurs, in other words, the 

temperature of the water table at the recharge location. 

The general method of determining recharge temperature from dissolved noble-gas concentrations is presented in Stute and Schlosser (2000). Whereas 

oxygen-18 and deuterium data can be used to determine the relative magnitude of MFR (MBR and stream 

loss combined) to intermountain basin-fill aquifers, 

recharge temperature can be used to calculate the relative contribution of MBR, specifically (Manning and 

Solomon, 2003). For typical water-table depths, Tr

should be approximately equal to (within about 2°C) 

the mean annual air temperature at the recharge location. Because mean annual air temperature decreases 

markedly with increasing altitude (about 10.5°C per mi 

of altitude gain in northern Utah (Hely and others, 

1971)), MBR should have a colder Tr than valley 

recharge. MBR generally cannot be distinguished from 

stream infiltration that occurs near the mountain front 

on the basis of stable-isotope ratios because both 

sources carry a light, high-altitude signal. The ability 

to identify MBR specifically is important because, as 

noted above, MBR is considerably less likely to contain elevated levels of anthropogenic chemical compounds than recharge from stream loss or any other 

form of valley recharge. Both stream loss and MBR 

are potentially large components of recharge to intermountain basin-fill aquifers.

Dissolved-gas data for water from wells in Salt 

Lake Valley are presented in table 10. Samples collected with diffusion samplers and associated recharge 

temperature determinations are from Manning (2002). 

Recharge temperatures were not computed for samples 

collected in clamped copper tubes as part of this study 

because the University of Utah laboratory did not provide krypton determinations for samples collected in 

this manner. Hence, Tr data are not available for wells 

on the west side of the valley. 

Determining Tr in cases where the recharge altitude is initially unknown is not straightforward. Manning and Solomon (2003) present a detailed description 

of the method by which the maximum Tr (Trmax) and 

probable Tr (Trprob) were computed for water from 

wells in the eastern part of Salt Lake Valley by using 

dissolved concentrations of krypton, argon, neon, and 

nitrogen. The approach relies on initially determining 

a solution zone in recharge-altitude/recharge-temperature space by using valley water-table temperature 

measurements and Tr data from mountain springs with 

constrained recharge-altitude values. Uncertainty in 

Trmax is approximately plus or minus 1°C (Manning 

and Solomon, 2003).

Minimum and probable fractions of MBR in the 

sampled well waters were determined from Trmax and 

Trprob, respectively, assuming simple two-component 

mixing between MBR and valley recharge. A mean Tr

of 13°C was assumed for valley recharge because 

valley water-table temperatures are dominantly 12-

14°C (Manning and Solomon, 2003, fig. 7). Recharge 

temperatures for springs in the central Wasatch Mountains range from 0 to 10°C (Manning and Solomon, 

2003, fig. 7). A mean Tr of 2°C was thus assumed for 

the MBR component in computing the minimum MBR 

fraction, considering the very low likelihood that Tr

values for MBR are dominantly less than 2°C throughout the Wasatch Mountains (the colder the assumed 

mean Tr for MBR, the smaller the computed MBR fraction). Probable MBR fractions were computed by 

using Trprob instead of Trmax and a more likely mean Tr

of 5°C for MBR. Note that assuming a colder mean 

sample Tr (Trprob instead of Trmax) does not demand a 

colder mean Tr for the MBR component in the sample. 

Maximum recharge temperatures in the eastern 

part of the valley generally are well below 12 to 14°C 

(fig. 19), indicating that MBR must constitute a 
Sources of Ground-Water Recharge 41

Figure 19. Map showing Distribution of maximum recharge temperatures for water sampled from the principal aquifer on the east side of Salt Lake 

Valley, Utah, 2000.

EXPLANATION

Maximum recharge temperature in degrees Celsius

5 to 6 6 to 7 7 to 8 8 to 9 9 to 10 10 to 11 11 to 12

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Boundary of zone of principal aquifer referred to in text

7.4

Boundary between secondary recharge area and discharge area

Boundary between primary and secondary recharge areas

Approximate boundary of basin-fill deposits in Salt Lake Valley

Public-supply well—Number is maximum recharge temperature

determined for water from the well

Base from U.S. Geological Survey digital line graph data, 1:100,000 , 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

UTAH COUNTY

7.9

11.7

6.0

8.2

8.2

7.7

5.5

7.7

6.8

7.0

8.1

11.3

6.2

7.8

10.7

9.5

10.3

11.6

9.3

9.1

8.8

13.3

9.8

6.9 6.2

7.0

6.9

7.5

6.6

9.1

10.6 7.3

13.3

9.2

9.0

7.9

9.7

11.7 9.8

8.3

5.6

6.0

11.4

10.8

7.5

6.7

7.6

7.1

6.5

10.2

Parleys zone

Murray zone

Midvale zone

Sandy zone

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek

8.9
42 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

 Table 10. Dissolved-gas and recharge-temperature data for water sampled from public-supply wells in Salt Lake Valley, Utah, 2000-01

[Well identifier, wells 1-31 are the public-supply wells sampled for water quality and dissolved gases as part of this study and (or) by Manning (2002) and the 

others are public-supply wells sampled by Manning (2002); cm3STP/g, cubic centimeters at standard temperature and pressure per gram of water; oC, degrees 

Celsius; —, not analyzed; NC, not calculated because krypton data were not available; clamps, clamped copper tubes; DS, diffusion samplers; boxed samples 

were collected from the same well with both sample methods]

Well

 identifier 

(fig. 16)

Sample 

date

Sample

method

Helium Neon Argon Krypton Nitrogen

(cm3STP/g)

1 05/2001 clamps 1.11x10-6 1.83x10-7 3.61x10-4 — 1.48x10 -2

2 05/2001 clamps 6.31x10-8 2.69x10-7 4.65x10-4 — 1.87x10 -2

3 05/2001 clamps 5.71x10-7 2.23x10-7 4.09x10-4 — 1.56x10 -2

4 05/2001 clamps 6.58x10-8 2.66x10-7 4.46x10-4 — 1.78x10 -2

5 08/2000 DS 5.65x10-8 2.29x10-7 3.73x10-4 8.79x10-8 1.54x10 -2

6 06/2001 clamps 6.24x10-8 2.14x10-7 4.05x10-4 — 1.49x10 -2

7 05/2001 clamps 7.32x10-8 2.82x10-7 4.50x10-4 — 1.93x10 -2

8 07/2001 DS 5.86x10-8 2.48x10-7 3.93x10-4 8.84x10-8 1.67x10 -2

9 05/2001 clamps 1.60x10-7 2.24x10-7 4.32x10-4 — 1.65x10 -2

10 05/2001 clamps 6.13x10-7 2.86x10-7 4.35x10-4 — 1.82x10 -2

11 07/2000 DS 9.92x10-8 1.82x10-7 3.26x10-4 8.10x10-8 1.32x10 -2

12 08/2000 DS 7.32x10-8 3.08x10-7 4.28x10-4 9.42x10-8 1.92x10 -2

13 07/2000 DS 7.02x10-8 2.90x10-7 3.97x10-4 8.98x10-8 1.80x10 -2

14 05/2001 clamps 4.34x10-7 2.30x10-7 3.58x10-4 — 1.50x10 -2

15 06/2001 clamps 6.31x10-8 2.71x10-7 4.53x10-4 — 1.84x10 -2

16 06/2001 clamps 1.17x10-7 3.65x10-7 4.83x10-4 — 2.54x10 -2

17 07/2000 DS 6.70x10-8 2.67x10-7 3.74x10-4 8.63x10-8 1.65x10 -2

18 05/2001 clamps 1.27x10-7 2.42x10-7 3.52x10-4 — 1.36x10 -2

18 07/2000 DS 1.04x10-7 1.88x10-7 3.17x10-4 7.67x10-8 1.29x10 -2

19 05/2001 clamps 2.52x10-7 2.06x10-7 3.55x10-4 — 1.38x10 -2

19 08/2000 DS 2.41x10-7 2.01x10-7 3.35x10-4 7.89x10-8 1.36x10 -2

20 05/2001 clamps 1.84x10-6 2.56x10-7 4.21x10-4 — 1.77x10 -2

20 07/2000 DS 1.01x10-6 1.67x10-7 3.25x10-4 7.38x10-8 11.30x10 -2

21 08/2000 DS 2.39x10-7 2.09x10-7 3.56x10-4 8.25x10-8 1.45x10 -2

22 05/2001 clamps 6.92x10-8 2.81x10-7 4.31x10-4 — 1.80x10 -2

23 06/2001 clamps 6.05x10-8 2.11x10-7 3.64x10-4 — 1.43x10 -2

24 05/2001 clamps 7.29x10-8 2.41x10-7 4.19x10-4 — 1.65x10 -2

25 05/2001 clamps 1.57x10-6 2.20x10-7 4.26x10-4 — 1.67x10 -2

26 05/2001 clamps 8.97x10-8 2.48x10-7 4.37x10-4 — 1.77x10 -2

26 07/2000 DS 7.59x10-8 2.15x10-7 3.56x10-4 8.55x10-8 1.48x10 -2

27 06/2001 clamps 5.22x10-7 2.24x10-7 4.33x10-4 — 1.68x10 -2

28 05/2001 clamps 2.25x10-7 4.92x10-7 6.10x10-4 — 3.09x10 -2

29 05/2001 clamps 6.85x10-7 2.08x10-7 3.60x10-4 — 1.43x10 -2

30 06/2001 clamps 6.24x10-8 2.26x10-7 4.00x10-4 — 1.58x10 -2

30 08/2001 DS 5.41x10-8 1.83x10-7 3.34x10-4 7.74x10-8 1.34x10 -2

31 06/2001 clamps 5.32x10-8 2.18x10-7 3.93x10-4 — 1.54x10 -2

32 08/2000 DS 5.40x10-8 2.09x10-7 3.62x10-4 8.96x10-8 1.47x10 -2
Sources of Ground-Water Recharge 43

Table 10. Dissolved-gas and recharge-temperature data for water sampled from public-supply wells in Salt Lake Valley, Utah, 2000-01—Continued

Well 

identifier 

(fig. 16)

Maximum 

recharge 

temperature

(

oC)

Minimum 

excess air 

concentration

(cm3STP/g)

Minimum 

recharge 

altitude

(feet)

Minimum 

mountainblock 

recharge 

fraction

Probable 

recharge 

temperature

(

oC)

Probable 

excess air 

concentration 

(cm3STP/g)

Probable 

recharge 

altitude

(feet)

Probable 

mountainblock 

recharge 

fraction

1 NC NC NC NC NC NC NC NC

2 NC NC NC NC NC NC NC NC

3 NC NC NC NC NC NC NC NC

4 NC NC NC NC NC NC NC NC

5 6.8 .0029 4,801 .56 3.4 .0036 7,863 1.00

6 NC NC NC NC NC NC NC NC

7 NC NC NC NC NC NC NC NC

8 6.0 .0040 4,872 .64 2.3 .0048 8,284 1.00

9 NC NC NC NC NC NC NC NC

10 NC NC NC NC NC NC NC NC

11 9.3 .0005 4,544 .34 7.1 .0009 6,414 .73

12 5.5 .0072 4,905 .69 1.4 .0080 8,612 1.00

13 7.7 .0064 4,700 .48 4.7 .0069 7,349 1.00

14 NC NC NC NC NC NC NC NC

15 NC NC NC NC NC NC NC NC

16 NC NC NC NC NC NC NC NC

17 9.1 .0051 4,672 .36 7.0 .0055 6,463 .75

18 NC NC NC NC NC NC NC NC

18 11.6 .0010 4,413 .13 10.9 .0011 4,970 .26

19 NC NC NC NC NC NC NC NC

19 10.3 .0016 4,501 .25 8.7 .0019 5,807 .54

20 NC NC NC NC NC NC NC NC

20 11.3 .0000 4,331 .16 9.6 .0000 5,348 .42

21 8.1 .0020 4,675 .45 5.2 .0025 7,185 .97

22 NC NC NC NC NC NC NC NC

23 NC NC NC NC NC NC NC NC

24 NC NC NC NC NC NC NC NC

25 NC NC NC NC NC NC NC NC

26 NC NC NC NC NC NC NC NC

26 7.8 .0022 4,692 .47 4.8 .0028 7,327 1.00

27 NC NC NC NC NC NC NC NC

28 NC NC NC NC NC NC NC NC

29 NC NC NC NC NC NC NC NC

30 NC NC NC NC NC NC NC NC

30 8.8 .0006 4,528 .38 7.3 .0011 6,332 .71

31 NC NC NC NC NC NC NC NC

32 6.2 .0018 4,839 .62 2.5 .0025 8,202 1.00
44 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

 Table 10. Dissolved-gas and recharge-temperature data for water sampled from public-supply wells in Salt Lake Valley, Utah, 2000-01—Continued

Well

 identifier 

(fig. 16)

Sample 

date

Sample

method

Helium Neon Argon Krypton Nitrogen

(cm3STP/g)

33 07/2000 DS 4.76x10-8 2.00x10-7 3.40x10-4 7.99x10-8 1.39x10 -2

37 08/2000 DS 5.86x10-8 2.40x10-7 3.74x10-4 8.90x10-8 1.59x10 -2

38 08/2000 DS 5.03x10-8 2.09x10-7 3.52x10-4 8.59x10-8 1.44x10 -2

40 08/2000 DS 7.46x10-8 3.08x10-7 4.14x10-4 9.15x10-8 1.90x10 -2

44 08/2000 DS 9.15x10-7 1.75x10-7 3.30x10-4 8.07x10-8 11.33x10 -2

45 09/2000 DS 5.36x10-8 2.01x10-7 3.45x10-4 8.18x10-8 1.41x10 -2

47 08/2000 DS 5.38x10-8 2.24x10-7 3.63x10-4 8.25x10-8 1.52x10 -2

50 07/2000 DS 1.42x10-7 2.54x10-7 3.62x10-4 7.93x10-8 1.59x10 -2

68 08/2000 DS 1.30x10-7 2.06x10-7 3.60x10-4 8.88x10-8 1.48x10 -2

69 08/2000 DS 5.37x10-8 2.21x10-7 3.69x10-4 8.82x10-8 1.51x10 -2

70 08/2000 DS 5.27x10-8 2.05x10-7 3.19x10-4 7.28x10-8 11.44x10 -2

71 08/2000 DS 5.00x10-8 2.09x10-7 3.55x10-4 8.45x10-8 1.46x10 -2

72 08/2000 DS 6.32x10-8 2.60x10-7 3.84x10-4 8.48x10-8 1.66x10 -2

73 08/2000 DS 7.22x10-8 2.07x10-7 3.53x10-4 8.19x10-8 1.44x10 -2

74 08/2000 DS 5.09x10-8 2.07x10-7 3.44x10-4 7.78x10-8 1.40x10 -2

75 07/2000 DS 5.25x10-8 1.90x10-7 3.53x10-4 8.37x10-8 1.39x10 -2

76 08/2000 DS 5.09x10-8 1.80x10-7 3.30x10-4 7.99x10-8 1.30x10 -2

77 08/2000 DS 5.02x10-8 2.11x10-7 3.36x10-4 7.66x10-8 11.50x10 -2

78 07/2000 DS 9.45x10-8 2.05x10-7 3.61x10-4 8.92x10-8 1.47x10 -2

79 07/2000 DS 1.44x10-7 1.96x10-7 3.49x10-4 8.71x10-8 1.42x10 -2

80 07/2000 DS 4.67x10-8 1.96x10-7 3.34x10-4 8.00x10-8 1.38x10 -2

81 08/2000 DS 2.91x10-7 1.98x10-7 3.29x10-4 7.45x10-8 1.32x10 -2

82 08/2000 DS 1.88x10-7 2.15x10-7 3.62x10-4 8.45x10-8 1.47x10 -2

83 08/2000 DS 5.03x10-8 2.11x10-7 3.61x10-4 8.49x10-8 1.46x10 -2

84 08/2000 DS 7.88x10-8 2.14x10-7 3.65x10-4 8.82x10-8 1.53x10 -2

85 07/2000 DS 5.38x10-8 2.07x10-7 3.43x10-4 7.95x10-8 1.42x10 -2

86 07/2000 DS 8.97x10-8 2.37x10-7 3.58x10-4 8.36x10-8 1.55x10 -2

87 07/2000 DS 9.90x10-8 2.08x10-7 3.40x10-4 7.62x10-8 1.41x10 -2

88 07/2000 DS 9.05x10-8 2.07x10-7 3.29x10-4 7.75x10-8 1.37x10 -2

89 07/2000 DS 8.75x10-8 2.49x10-7 3.78x10-4 8.74x10-8 1.61x10 -2

90 07/2000 DS 5.69x10-8 2.17x10-7 3.66x10-4 8.63x10-8 1.50x10 -2

91 07/2000 DS 5.12x10-8 2.17x10-7 3.70x10-4 8.64x10-8 1.52x10 -2

92 08/2000 DS 5.58x10-8 2.32x10-7 3.69x10-4 8.56x10-8 1.55x10 -2

93 07/2000 DS 9.61x10-8 2.09x10-7 3.48x10-4 8.26x10-8 1.42x10 -2

94 07/2000 DS 5.51x10-8 2.32x10-7 3.68x10-4 8.67x10-8 1.55x10 -2

95 07/2000 DS 6.59x10-8 2.36x10-7 3.74x10-4 8.73x10-8 1.59x10 -2

96 07/2000 DS 1.75x10-7 1.92x10-7 3.31x10-4 8.15x10-8 11.39x10 -2

97 08/2000 DS 1.98x10-7 1.88x10-7 3.27x10-4 7.62x10-8 1.33x10 -2

1 Nitrogen gas concentration was excluded in determination of recharge temperature, excess air concentration, and recharge elevation because 

denitrification was likely.
Sources of Ground-Water Recharge 45

Table 10. Dissolved-gas and recharge-temperature data for water sampled from public-supply wells in Salt Lake Valley, Utah, 2000-01—Continued

Well 

identifier 

(fig. 16)

Maximum 

recharge 

temperature

(

oC)

Minimum 

excess air 

concentration

(cm3STP/g)

Minimum 

recharge 

altitude

(feet)

Minimum 

mountainblock 

recharge 

fraction

Probable 

recharge 

temperature

(

oC)

Probable 

excess air 

concentration 

(cm3STP/g)

Probable 

recharge 

altitude

(feet)

Probable 

mountainblock 

recharge 

fraction

33 9.5 .0016 4,511 .32 7.5 .0020 6,283 .69

37 7.0 .0035 4,774 .55 3.6 .0042 7,759 1.00

38 7.4 .0019 4,961 .51 4.7 .0025 7,349 1.00

40 6.7 .0074 4,941 .57 3.7 .0080 7,726 1.00

44 9.1 .0000 4,555 .36 6.5 .0005 6,660 .81

45 7.9 .0017 5,282 .47 6.1 .0020 6,808 .86

47 8.2 .0029 4,721 .43 5.6 .0034 7,021 .92

50 10.7 .0049 4,783 .21 10.2 .0049 5,200 .35

68 6.2 .0017 4,856 .62 2.5 .0024 8,202 1.00

69 6.6 .0025 4,806 .58 3.1 .0032 8,005 1.00

70 13.3 .0021 4,662 .00 13.3 .0021 4,662 .00

71 7.5 .0020 4,872 .50 4.7 .0025 7,365 1.00

72 8.2 .0047 4,734 .44 5.6 .0053 7,021 .93

73 8.3 .0020 4,626 .42 5.6 .0025 7,021 .92

74 10.2 .0020 4,462 .26 8.5 .0023 5,873 .56

75 7.0 .0009 4,774 .55 3.7 .0016 7,776 1.00

76 9.0 .0005 4,800 .37 7.1 .0008 6,441 .74

77 11.7 .0022 4,324 .12 10.8 .0023 5,003 .27

78 6.0 .0016 4,888 .64 2.2 .0023 8,317 1.00

79 6.9 .0011 4,774 .56 3.4 .0018 7,874 1.00

80 9.7 .0014 4,506 .30 7.7 .0018 6,190 .66

81 11.7 .0016 4,452 .12 11.3 .0017 4,823 .22

82 7.6 .0022 4,692 .49 4.6 .0028 7,431 1.00

83 7.3 .0020 4,790 .52 4.2 .0026 7,579 1.00

84 5.6 .0023 5,400 .67 2.6 .0029 8,202 1.00

85 9.8 .0020 4,495 .29 7.8 .0024 6,135 .64

86 9.2 .0036 4,623 .35 7.0 .0040 6,480 .75

87 10.8 .0021 4,439 .20 9.6 .0024 5,446 .43

88 11.4 .0021 4,508 .15 10.8 .0022 4,970 .27

89 7.5 .0040 4,708 .50 4.4 .0047 7,480 1.00

90 6.9 .0023 4,774 .56 3.5 .0030 7,841 1.00

91 6.5 .0023 4,806 .59 2.9 .0031 8,071 1.00

92 7.7 .0032 4,692 .49 4.6 .0038 7,431 1.00

93 8.9 .0019 4,578 .37 6.4 .0024 6,693 .82

94 7.9 .0034 4,675 .46 4.9 .0040 7,283 1.00

95 7.1 .0034 4,757 .54 3.8 .0040 7,726 1.00

96 9.8 .0010 4,478 .29 7.8 .0014 6,168 .65

97 10.6 .0010 4,541 .22 9.4 .0013 5,512 .45
46 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 20. Map showing Distribution of minimum mountain-block recharge fractions for water sampled from the principal aquifer on the east side of Salt 

Lake Valley, Utah, 2000.

EXPLANATION

Minimum mountain-block recharge fraction

0.7 to 0.6 0.6 to 0.5 0.5 to 0.4 0.4 to 0.3 0.3 to 0.2 0.2 to 0.1

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Boundary of zone of principal aquifer referred to in text

0.51

Boundary between secondary recharge area and discharge area

Boundary between primary and secondary recharge areas

Approximate boundary of basin-fill deposits in Salt Lake Valley

Well completed in principal aquifer—Number is minimum mountainblock recharge fraction

Base from U.S. Geological Survey digital line graph data, 1:100,000 , 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

UTAH COUNTY

0.47

0.12

0.64

0.44

0.43

0.48

0.69

0.49

0.56

0.55

0.45

0.16

0.62

0.47

0.21

0.32

0.25

0.13

0.34

0.36

0.38

0

0.29

0.56

0.62

0.55

0.56

0.50

0.37

0.58

0.36

0.22

0.52

0

0.35

0.37

0.46

0.30

0.12

0.29

0.42

0.67

0.64

0.15

0.20

0.50

0.57

0.49

0.54

0.59

0.26

Parleys zone

Murray zone

Midvale zone

Sandy zone

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
Sources of Ground-Water Recharge 47

substantial fraction of recharge to the principal aquifer 

in this area. Maximum recharge temperatures are 

particularly low in the southeastern part of the valley 

where Trmax generally ranges from 6 to 9°C. Minimum 

fractions of MBR computed from Trmax values indicate 

that MBR constitutes at least 30 percent of recharge 

throughout most of the east side of the valley, and at 

least 45 percent in the southeastern part (fig. 20). 

Probable fractions of MBR (table 10) indicate that 

water in the southeastern area more likely consists of 

80 to 100 percent MBR. An important consideration in 

interpreting the recharge-temperature data is that, 

although low Trmax values can be explained only by 

high MBR fractions, high Trmax values do not 

necessarily indicate low MBR fractions. Another 

possible explanation of high Trmax values is that the Tr

of MBR is high because either (1) MBR occurs mainly 

at lower altitudes in the mountains, or (2) the water 

table in the mountains is deep. A deep water table in 

the mountain block could result in water-table 

temperatures well above the mean annual air 

temperature at the surface because of the geothermal 

gradient.

To a first order, minimum MBR fractions are 

consistent with the minimum MFR fractions on the east 

side of the valley (figs. 18 and 20). The recharge-temperature and stable-isotope data together indicate that 

MBR, and thus MFR, constitutes a significant percentage of recharge to the principal aquifer on the east side 

of the valley. In turn, this result generally is consistent 

with previous estimates of MBR and MFR to the principal aquifer in Salt Lake Valley (Hely and others, 

1971; Waddell and others, 1987b; Lambert, 1995). In 

the most recently published ground-water flow model 

of the valley (Lambert, 1995), MBR accounts for more 

than 70 percent of recharge throughout most of the east 

side. Because MFR includes both MBR and stream 

loss, the minimum MBR fraction should not significantly exceed the minimum MFR fraction in a given 

location. This is indeed the case for water from wells 

where both values were calculated, except for well 21 

(minimum MFR fraction = 0.27, minimum MBR fraction = 0.45). This discrepancy may be a result of the 

non-MFR fraction containing evaporated canal water, 

thus having a δ18O ratio heavier than -14.7 per mil. 

Increasing the non-MFR component to -13.5 per mil, 

for example, results in a MFR fraction of 0.55, consistent with the minimum MBR fraction. Well 21 is in 

one of the two small areas of canal loss on the east side 

of the valley (north of Little Cottonwood Canyon) in 

Lambert’s (1995) model of Salt Lake Valley. The distribution of minimum MBR fractions and minimum 

MFR fractions also indicates that the valley recharge 

component is probably large in the Murray and Midvale zones, which are defined on figures 18 and 20 (see 

following discussion regarding well susceptibility).

Substantial discrepancies do exist, however, 

between the minimum MBR and MFR fractions in the 

Parleys and Sandy zones (figs. 18 and 20). In both of 

these areas, the MBR fractions are relatively low (0.12 

to 0.36), whereas the MFR fractions are relatively high 

(0.69 to 1.0). In fact, MFR fractions in the Parleys 

zone are the highest calculated for the principal aquifer. 

One possible explanation for this discrepancy is that 

stream loss constitutes an exceptionally high percentage of MFR in these two areas. This is unlikely in the 

Parleys zone, however, where stream data coupled with 

water-budget analysis (Hely and others, 1971) and 

numerical modeling (Waddell and others, 1987b; Lambert, 1995) indicates that stream seepage accounts for 

only about 5 to 10 percent of total recharge. This compares to 10 to 30 percent farther south. Although some 

error in these stream-loss percentages is to be expected, 

the very large errors demanded in the case of stream 

loss comprising a high percentage of recharge in the 

Parleys zone are unlikely. High stream-loss rates also 

are unlikely in the Sandy zone because several wells 

located between the Sandy zone and Little Cottonwood 

Creek have higher MBR fractions (and lower MFR 

fractions) than wells in the Sandy zone; stream seepage 

increasing with distance from the stream is not likely.

Another possible explanation for the discrepancy 

between minimum MBR and MFR fractions in the Parleys and Sandy zones is that the ground water in these 

areas is dominantly valley recharge that infiltrated several thousand years ago (paleowater). Ground water of 

this age might have recharged when the local climate 

was colder. Recharge from precipitation in a colder 

paleoclimate would have lighter δ18O values than 

recent recharge. Given this scenario, noble gas concentrations from most wells in the Parleys and Sandy 

zones indicate that valley recharge temperatures were 2 

to 3°C colder several thousand years ago, in turn indicating a climatic shift in the mean annual air temperature of 2 to 3°C. Assuming a reasonable isotopic shift 

of 0.7 per mil/°C (Mazor, 1991, p. 177), this climatic 

shift in the mean annual air temperature would result in 

δ18O values generally consistent with those observed in 

the Parleys and Sandy areas (-16 to -17 per mil). 

Ground water in the study area has not been dated with 
48 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

techniques appropriate for ages on this time scale. Tritium concentrations (“Tritium and Tritium/Helium-3 

Ages” section of this report) in the Sandy zone and the 

western part of the Parleys zone are approximately 1 

TU or less, consistent with the possibility of ground 

water in these areas being dominantly paleowater 

(which would be tritium free). In the eastern part of the 

Parleys zone, however, where disagreement between 

minimum MBR and MFR fractions is the greatest, 3H 

concentrations are 4 to 14 TU, indicating that a substantial fraction of the ground water is younger than 50 

years. The presence of paleowater is therefore capable 

of explaining, by itself, the discrepancy between the 

minimum MBR and MFR fractions in the Sandy zone 

and western Parleys zone, but not in the eastern Parleys 

zone.

A third possible explanation for the discrepancy 

is that MBR in the Parleys and Sandy zones has a warm 

mean Tr as a result of a deep mountain water table in 

the MBR source area. Recharge temperatures for 

springs in the mountains adjacent to these areas are not 

anomalously warm (Manning, 2002, tables A.5 and 

A.6). However, it is possible that these springs are fed 

by a shallow ground-water system perched above a 

deeper regional ground-water table, as is thought to be 

the case in some mountains in the Basin and Range 

Province (Maurer and others, 1996). The general lack 

of perennial side-canyon streamflow in Parleys and 

Emigration Canyons is consistent with a deep water 

table in the mountains adjacent to the Parleys zone. 

Both deep mountain water tables and the occurrence of paleowater are consistent with anomalously 

warm ground-water temperatures (Manning, 2002, 

figure 4.4) and elevated terrigenic 4He concentrations 

(generally greater than or equal to 5x10-8 cm3STP/g, 

see “Tritium and Tritium/Helium-3 Ages” section of 

this report) in the Parleys and Sandy zones. Terrigenic 

He originates from radioactive decay of natural uranium- and thorium-series elements in aquifer solids 

and has been used to date ground water over timescales 

of 1,000 to 1,000,000 years (Solomon, 2000). Warmer 

temperatures and elevated terrigenic 4He concentrations are indicative of deeper ground-water circulation 

and longer ground-water residence times. Deep 

ground-water circulation is a corollary of a deep water 

table. Note, however, that circulation is not necessarily 

shallower in other parts of the mountain block where 

water tables are shallower.

Deeper ground-water circulation in the mountains adjacent to the Parleys zone is consistent with the 

mountain block geology (fig. 18). Rocks from Mill 

Creek Canyon northward are dominantly sedimentary, 

with bedding planes and major faults striking approximately perpendicular to the mountain front. Rocks farther south are dominantly crystalline, and major faults 

strike more parallel to the mountain front. The mountain block adjacent to the Parleys zone may therefore 

be more permeable, particularly at depth, allowing 

deeper ground-water circulation. Such is not the case 

for the mountain block adjacent to the Sandy zone, 

which consists of relatively undeformed granitic intrusive rocks. It is possible, however, that the source area 

for MBR in the Sandy zone is south of the study area, 

where sedimentary rocks predominate.

In summary, the cause of the discrepancy 

between minimum MBR and MFR fractions in the 

Sandy and Parleys zones is unclear. The discrepancy 

may be the result of a deep mountain water table (causing MBR to have a warm mean Tr), the occurrence of 

paleowater, some combination of these two factors, or 

other conditions we have not considered here. Because 

MBR may have an anomalously warm Tr in these areas, 

MBR may not be low as indicated by the low minimum 

MBR fractions. It is important to note that low MBR 

rates in the Parleys zone would conflict with previous 

MBR estimates for this part of the basin, which are 

similar to or greater than MBR rates farther south 

(Hely and others, 1971; Waddell and others, 1987b; 

Lambert, 1995). More data from the Parleys and Sandy 

zones are clearly needed.

A close correlation exists between dissolvedsolids concentration and minimum MBR fractions on 

the east side of Salt Lake Valley (figs. 8 and 20). 

Ground water with a dissolved-solids concentration of 

less than 250 mg/L in the southeastern part of the 

valley also is characterized by high minimum MBR 

fractions. This correlation could be the result of MBR 

generally having lower dissolved-solids concentrations 

than valley recharge, coupled with MBR fractions 

being higher in the south than in the north. However, it 

is also possible that MBR fractions are not significantly 

higher in the southeastern part of the valley (see above 

discussion), and that the correlation is instead primarily 

a function of the mountain-block geology. As previously noted, rocks in the mountain block adjacent to 

the southeastern part of the valley are dominantly crystalline, whereas rocks adjacent to the northeastern part 

are dominantly sedimentary (fig. 8). Spring data from 
Sources of Ground-Water Recharge 49

the central Wasatch Range (Mayo and Loucks, 1995, 

table 1) indicate that MBR in the southeastern area 

should have a dissolved-solids concentration that 

ranges from 100 to 200 mg/L, and MBR in the northeastern area should have a concentration of from 200 to 

600 mg/L. Concentrations in the southeastern and 

northeastern parts of the valley do generally fall within 

these ranges (fig. 8).

The minimum MBR fraction potentially could 

serve as an important indicator of well susceptibility. 

Wells with low minimum MBR fractions (possibly 

high valley recharge fractions) should be more susceptible than wells with high minimum MBR fractions. 

Wells with minimum MBR fractions substantially 

lower than nearby upgradient wells should be the most 

susceptible because in this case the low minimum 

MBR fraction probably indicates a high valley recharge 

fraction (as opposed to MBR with a warmer Tr). 

Together, the stable-isotope and recharge-temperature data define two zones of apparently high susceptibility on the east side of the valley, the Murray 

zone and the Midvale zone (figs. 18 and 20). The 

Murray zone includes wells 31, 77, 80, and 85, and the 

Midvale zone includes wells 20, 42, and 74 (fig. 16). 

In these two zones, both minimum MFR fractions and 

minimum MBR fractions are low, and minimum MBR 

fractions are considerably lower than upgradient wells 

to the east and southeast. The Murray zone may extend 

farther southeast to well 33 because this well has a low 

minimum MBR fraction (0.32), but the minimum MFR 

fraction for well 33 is not low (0.82). Similarly, the 

Midvale zone may extend farther south to well 21 

because this well has a low minimum MFR fraction 

(0.27), but the minimum MBR fraction for this well is 

not low (0.45).

Other areas on the east side of the valley have 

potentially high levels of susceptibility. Minimum 

MFR and MBR fractions are both low in the area just 

south of Mill Creek near the mountain front (wells 50 

and 86 (MFR = 0.44, MBR = 0.21, 0.32)). However, it 

is possible that this area simply receives more MBR 

from lower altitudes. Well 1 west of the Murray zone 

near the Jordan River has a low minimum MFR fraction (0.41). No recharge temperature data were collected in the vicinity of this well. Minimum MBR 

fractions are low in the Sandy and eastern Parleys 

zones, but, as discussed above, minimum MFR fractions are not. Minimum MBR fractions in the Sandy 

zone are considerably lower than in areas to the east 

and southeast. However, ground water might flow to 

the Sandy zone largely from the south where minimum 

MBR fractions are unknown.

Tritium and Tritium/Helium-3 Ages

Tritium (3H) is a radioactive isotope of hydrogen 

with a half-life of 12.43 years. It decays to the noblegas isotope 3He. Tritium naturally produced in the 

upper atmosphere occurs in precipitation, bound in 

water molecules, at concentrations of about 6 to 8 TU. 

Thermonuclear testing in the 1950s and 1960s introduced large amounts of 3H to the atmosphere, causing 

3H concentrations in precipitation to peak in the early 

1960s at more than 1,000 TU throughout the northern 

hemisphere. The measured ratio of 3H to tritiogenic 

3He (3Hetrit) provides an age of the sampled water from 

the time it enters the saturated zone and becomes isolated from the atmosphere. Accuracy of the determined 

age can be affected by mixing between waters with different ages, dispersion, and other factors and, therefore, 

is qualified by using the term “apparent age.” Given 

present analytical capabilities, the 3H/3He method can 

be used to date water younger than about 50 years. 

Details regarding the 3H/3He dating technique can be 

found in Solomon and Cook (2000).

3H/3He age data for water from wells in Salt 

Lake Valley are presented in table 11. The 2001 samples were collected as part of this study (February and 

August 2001 samples from well 30 being the only 

exception). Data for samples collected in 2000 are 

from Manning (2002). More than one sample was collected at selected wells. For 3H samples collected 

without a concurrent dissolved-gas sample, an age was 

calculated by using the 3Hetrit concentration determined for another sample from the same well. Apparent 3H/3He ages were computed for samples collected 

by Manning (2002) by using the probable recharge 

temperature and altitude (table 10). For samples collected as part of this study (in clamped copper tubes), 

apparent age was calculated by using a recharge temperature and altitude similar to those determined for 

neighboring wells, when possible; otherwise, a Tr of 

9°C and a recharge altitude of 5,250 ft (corresponding 

to the valley/mountain transition) were assumed. 

Uncertainty in the apparent age resulting from uncertainty in the recharge temperature and altitude, along 

with analytical uncertainty, is plus or minus 3 years or 

less (Manning, 2002, appendix B).
50 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table 11. Tritium/helium-3 age data for water sampled from public-supply wells in Salt Lake Valley, Utah, 2000-01—Continued

Well 

identifier

(fig. 16)

Sample 

date

Tritium

(TU) R/Ra

4

Heterr

(cm3STP/g)

Terrigenic

3He/4He

ratio

3

Hetrit

(TU)

Apparent 

age

(year)

Apparent 

recharge 

year

Initial 

tritium

(TU)

Interpreted age 

category

1 05/2001 8.5 0.28 1.07x10-6 9.00x10-8 111.0 47 1954 119.5 modern or mixture

2 05/2001 25.7 1.98 -3.08x10-9 2.77x10-8 33.3 15 1986 59.0 modern or mixture

3 05/2001 .3 .23 5.19x10-7 1.70x10-7 7.7 >50 pre-1950 8.0

13 05/2001 .5 — — 1.70x10-7 — 50 1951 8.2

3 average .4 .23 5.19x10-7 1.70x10-7 7.7 >50 pre-1950 8.1 pre-bomb

4 05/2001 1.7 1.22 3.67x10-10 2.77x10-8 8.6 32 1969 10.3 pre-bomb

5 08/2000 4.0 1.74 1.51x10-9 2.77x10-8 24.2 35 1965 28.1

15 05/2001 2 6.6 — — 2.77x10-8 — 28 1973 30.8

5 average 5.3 1.74 1.51x10-9 2.77x10-8 24.2 31 1969 29.4 modern or mixture

6 06/2001 .5 .85 1.10x10-8 1.00x10-8 1.2 21 1980 1.7 pre-bomb

7 05/2001 13.3 2.24 2.41x10-9 2.77x10-8 51.9 29 1972 65.2

17 05/2001 15.1 — — 2.77x10-8 — 27 1974 67.0

17 05/2001 2 16.0 — — 2.77x10-8 — 26 1975 67.9

7 average 14.8 2.24 2.41x10-9 2.77x10-8 51.9 27 1974 66.7 modern

8 07/2000 22.3 2.01 -2.08x10-9 2.77x10-8 32.0 16 1984 54.2

18 06/2001 221.4 — — 2.77x10-8 — 16 1985 53.4

8 average 21.9 2.01 -2.08x10-9 2.77x10-8 32.0 16 1984 53.8 modern

9 05/2001 .2 .37 1.06x10-7 1.00x10-8 3.4 >50 pre-1950 3.6 pre-bomb

10 05/2001 12.4 .36 5.41x10-7 2.77x10-8 78.4 36 1965 90.9 modern or mixture

11 07/2000 .5 .49 5.77x10-8 1.00x10-8 3.7 38 1962 4.2

111 06/2001 2.2 — — 1.00x10-8 — >50 pre-1950 3.9

11 average .4 .49 5.77x10-8 1.00x10-8 3.7 38 pre-1950 4.0 pre-bomb

12 08/2000 21.2 1.51 -4.13x10-9 2.77x10-8 18.6 11 1989 39.9

112 05/2001 220.6 — — 2.77x10-8 — 12 1989 39.2

12 average 20.9 1.51 -4.13x10-9 2.77x10-8 18.6 12 1989 39.6 modern

13 07/2000 13.4 1.43 -2.66x10-9 2.77x10-8 15.5 14 1986 28.9

113 06/2001 211.9 — — 2.77x10-8 — 15 1986 27.4

13 average 12.7 1.43 -2.66x10-9 2.77x10-8 15.5 14 1986 28.1 modern

14 05/2001 13.8 .40 3.78x10-7 2.77x10-8 62.0 31 1970 75.8 modern or mixture

15 06/2001 17.7 1.57 -3.49x10-9 2.77x10-8 18.2 13 1988 35.8 modern

16 06/2001 5.3 1.04 2.37x10-8 2.77x10-8 16.1 25 1976 21.4 modern or mixture

17 07/2000 12.5 1.44 5.06x10-10 2.77x10-8 16.6 15 1985 29.0

117 05/2001 211.0 — — 2.77x10-8 — 17 1984 27.6

17 average 11.8 1.44 5.06x10-10 2.77x10-8 16.6 16 1985 28.3 modern

18 05/2001 6.1 .68 6.76x10-8 2.77x10-8 14.5 22 1979 20.6

118 05/2001 5.9 — — 2.77x10-8 — 22 1979 20.4

118 05/2001 2 6.6 — — 2.77x10-8 — 21 1980 21.1

18 07/2000 7.3 .73 6.04x10-8 2.77x10-8 17.2 22 1978 24.5

18 average 6.5 .71 6.40x10-8 2.77x10-8 15.9 22 1979 21.7 modern or mixture

Table 11. Tritium/helium-3 age data for water sampled from public-supply wells in Salt Lake Valley, Utah, 2000-01

[Well identifier, wells 1-31 are the public-supply wells sampled for water quality and tritium as part of this study and (or) by Manning (2002) and the others are 

public-supply wells sampled by Manning (2002); TU, tritium units; R, measured 3He/4He ratio of the sample; Ra, atmospheric 3He/4He ratio; 4Heterr, terrigenic 

helium-4; cm3STP/g, cubic centimeters at standard temperature and pressure per gram of water; 3He, helium-3; 4He, helium-4; 3Hetrit, tritiogenic helium-3; 

Interpreted age category: modern or mixture, modern or mixture of modern and pre-bomb water; modern, dominantly modern water; pre-bomb, dominantly 

pre-bomb water; —, not analyzed or applicable; >, greater than; boxed samples were collected from the same well]
Sources of Ground-Water Recharge 51

19 05/2001 23.0 .31 2.02x10-7 2.77x10-8 13.7 31 1970 16.7

19 08/2000 4.5 .31 1.97x10-7 2.77x10-8 12.8 24 1976 17.4

19 average 3.8 .31 2.00x10-7 2.77x10-8 13.3 27 1973 17.0 modern or mixture

20 05/2001 9.1 .24 1.77x10-6 1.30x10-7 116.8 47 1954 125.9

20 07/2000 15.3 0.33 9.74x10-7 2.77x10-8 152.7 43 1957 168.0

20 average 12.2 .28 1.37x10-6 7.89x10-8 134.7 45 1955 147.0 modern or mixture

21 08/2000 8.9 .59 1.91x10-7 2.77x10-8 48.5 33 1967 57.4

1 21 06/2001 2 7.6 — — 2.77x10-8 — 36 1965 56.1

21 average 8.3 .59 1.91x10-7 2.77x10-8 48.5 35 1966 56.7 modern or mixture

22 05/2001 10.7 1.47 -1.34x10-9 2.77x10-8 17.9 18 1983 28.6 modern

23 06/2001 .1 .79 9.83x10-9 1.00x10-8 -1.2 > 50 pre-1950 -1.2 pre-bomb

24 05/2001 .4 .77 1.36x10-8 1.00x10-8 -1.4 > 50 pre-1950 -1.0

1 24 05/2001 2 .0 — — 1.00x10-8 — > 50 pre-1950 -1.4

24 average .2 .77 1.36x10-8 1.00x10-8 -1.4 > 50 pre-1950 -1.2 pre-bomb

25 05/2001 .3 .15 1.52x10-6 1.50x10-7 7.8 >50 pre-1950 8.0 pre-bomb

26 05/2001 2 9.6 1.25 2.89x10-8 2.77x10-8 28.4 25 1976 38.0

26 07/2000 8.7 1.27 2.50x10-8 2.77x10-8 25.1 24 1976 33.8

26 average 9.2 1.26 2.70x10-8 2.77x10-8 26.7 25 1976 35.9 modern or mixture

27 06/2001 2.2 .32 4.70x10-7 1.80x10-7 29.0 48 1953 31.2 pre-bomb

28 05/2001 .1 .62 9.54x10-8 2.77x10-8 4.8 >50 pre-1950 4.9 pre-bomb

29 05/2001 .1 .19 6.36x10-7 1.50x10-7 8.2 >50 pre-1950 8.3 pre-bomb

30 06/2001 11.3 1.42 7.77x10-9 2.77x10-8 18.9 18 1983 30.1

1 30 06/2001 2 11.8 — — 2.77x10-8 — 17 1984 30.7

30 08/2001 11.2 1.45 1.12x10-8 2.77x10-8 19.8 19 1982 31.0

1 30 02/2001 9.4 — — 2.77x10-8 — 20 1981 29.2

30 average 10.9 1.43 9.49x10-9 2.77x10-8 19.3 19 1982 30.3 modern

31 06/2001 12.1 1.48 8.00x10-10 2.77x10-8 15.0 14 1987 27.1 modern

32 08/2000 4.3 1.29 5.25x10-9 2.77x10-8 11.7 24 1976 16.0 modern or mixture

33 07/2000 20.7 3.58 -5.10x10-11 2.77x10-8 68.6 26 1974 89.2 modern

37 08/2000 3.6 1.49 6.71x10-10 2.77x10-8 16.5 31 1969 20.1 modern or mixture

38 08/2000 15.1 2.09 8.93x10-10 2.77x10-8 31.1 20 1980 46.2 modern

44 08/2000 .3 .20 8.84x10-7 2.10x10-7 6.7 >50 pre-1950 7.0 pre-bomb

45 09/2000 12.2 .97 5.96x10-9 2.77x10-8 2.3 3 1997 14.5 modern

47 08/2000 3.9 1.38 -5.40x10-10 2.77x10-8 11.2 24 1976 15.1 modern or mixture

50 07/2000 14.9 .52 7.87x10-8 2.77x10-8 4.7 5 1995 19.7 modern

68 08/2000 12.0 .49 8.23x10-8 2.77x10-8 7.6 9 1991 19.5 modern

69 08/2000 2.2 1.15 1.06x10-9 2.77x10-8 5.2 22 1978 7.4 pre-bomb

70 08/2000 3.5 1.16 2.64x10-9 2.77x10-8 6.3 18 1982 9.8 modern or mixture

72 08/2000 7.7 1.71 -1.29x10-9 2.77x10-8 24.4 26 1974 32.1 modern or mixture

73 08/2000 9.4 1.33 2.29x10-8 2.77x10-8 25.7 24 1976 35.1 modern or mixture

75 07/2000 .4 .99 7.91x10-9 1.00x10-8 4.0 43 1957 4.3 pre-bomb

76 08/2000 14.1 1.00 9.25x10-9 2.77x10-8 4.9 5 1995 19.0 modern

77 08/2000 13.4 1.82 -7.47x10-10 2.77x10-8 22.5 18 1982 36.0 modern

78 07/2000 .2 .61 4.75x10-8 2.77x10-8 5.1 >50 pre-1950 5.4 pre-bomb

79 07/2000 .4 .38 1.00x10-7 1.00x10-8 4.5 45 1955 4.9 pre-bomb

Table 11. Tritium/helium-3 age data for water sampled from public-supply wells in Salt Lake Valley, Utah, 2000-01—Continued

Well 

identifier

(fig. 16)

Sample 

date

Tritium

(TU) R/Ra

4Heterr

(cm3STP/g)

Terrigenic

3He/4He

ratio

3

Hetrit

(TU)

Apparent 

age

(year)

Apparent 

recharge 

year

Initial 

tritium

(TU)

Interpreted age 

category
52 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Uncertainty in the apparent 3H/3He ages is controlled mainly by the terrigenic 4He (4Heterr) concentration (Plummer and others, 2000; Holocher and 

others, 2001). As noted above, terrigenic 4He results 

from subsurface nuclear reactions (uranium- and thorium-series decay within the Earth’s crust). Helium-3 

also is produced in these reactions. The ratio of 3He to 

4He produced (terrigenic 3He/4He ratio) is poorly constrained, so apparent ages for samples with elevated 

4Heterr concentrations are more uncertain. Water from 

most of the sampled wells (43 of 64) has relatively low 

4Heterr (concentrations less than 5x10-8 cm3STP/g) 

(table 11). Uncertainties in apparent ages from these 

wells are generally plus or minus 3 years or less (Manning, 2002, appendix B). Apparent ages for wells with 

4Heterr concentrations greater than 5x10-8 cm3STP/g 

have greater uncertainties. Apparent 3H/3He ages 

determined for different water samples collected from 

the same well generally differ by less than 5 years 

(table 11), even though these samples were collected 

about a year apart in many cases.

Because the sampled wells are public-supply 

wells that generally have long open intervals (typically 

150 to 500 ft), the samples likely contain a mixture of 

waters with different ages. The manner in which 

mixing complicates the interpretation of apparent 

3H/3He ages is discussed in Maloszewski and Zuber 

(1982). The most significant concern for the purposes 

of this study is potential mixing between water 

recharged before thermonuclear testing began in the 

early 1950s and water recharged during and after the 

testing period. The apparent 3H/3He age of such mixtures of modern water (younger than about 50 years) 

and pre-bomb water (older than about 50 years) is 

approximately the age of the modern fraction, meaning 

that the apparent age can be substantially younger than 

the flow-weighted mean age.

Whether or not a sample might contain a substantial fraction of pre-bomb water can be determined 

by comparing the initial 3H concentration of the sample 

(measured 3H + measured 3Hetrit) to that of local precipitation at the apparent time of recharge (apparent 

recharge year). For an unmixed sample, the initial 3H 

concentration represents the 3H concentration of the 

sampled water at the time of recharge, and it should be 

approximately equal to the 3H concentration in precipitation at the time of recharge. A sample with an initial 

3H concentration less than that expected based on the 

local precipitation 3H record may contain an appreciable fraction of pre-bomb water, meaning that its apparent age may be biased young. Initial 3H concentrations 

for water from the public-supply wells are plotted in 

figure 21 along with mean annual 3H concentrations in 

precipitation in Salt Lake City from 1953 to 2000. 

80 07/2000 15.4 1.60 8.97x10-11 2.77x10-8 15.7 13 1987 31.2 modern

81 08/2000 17.8 .69 2.35x10-7 2.77x10-8 78.9 30 1970 96.7 modern or mixture

83 08/2000 8.8 1.67 1.67x10-10 2.77x10-8 18.8 21 1979 27.6 modern

84 08/2000 14.7 1.26 2.82x10-8 2.77x10-8 27.0 19 1981 41.7 modern

85 07/2000 14.5 2.14 4.12x10-9 2.77x10-8 36.5 23 1977 51.0 modern

86 07/2000 16.8 .97 3.21x10-8 2.77x10-8 15.8 12 1988 32.6 modern

87 07/2000 10.1 .71 4.91x10-8 2.77x10-8 10.6 13 1987 20.6 modern

88 07/2000 13.9 .94 4.08x10-8 2.77x10-8 19.1 16 1984 33.0 modern

89 07/2000 14.4 1.27 2.68x10-8 2.77x10-8 27.8 19 1981 42.2 modern

90 07/2000 19.1 3.29 5.36x10-9 2.77x10-8 75.8 29 1971 95.0 modern

92 08/2000 29.6 3.10 -4.89x10-10 2.77x10-8 65.1 21 1979 94.7 modern

93 07/2000 16.5 1.10 4.66x10-8 2.77x10-8 30.7 19 1981 47.2 modern

94 07/2000 9.0 1.50 5.82x10-10 2.77x10-8 15.6 18 1982 24.6 modern

96 07/2000 1.1 .30 1.32x10-7 1.00x10-8 3.3 25 1975 4.5 pre-bomb

97 08/2000 1.2 .34 1.54x10-7 2.77x10-8 11.4 42 1958 12.6 pre-bomb

1 Replicate tritium sample. Data from corresponding dissolved-gas sample collected from the same well were used to determine age.

2 Tritium analysis done by U.S. Geological Survey laboratory. All other tritium analyses done by University of Utah, Department of Geology and 

Geophysics, Tritium and Noble Gases Laboratory.

Table 11. Tritium/helium-3 age data for water sampled from public-supply wells in Salt Lake Valley, Utah, 2000-01—Continued

Well 

identifier

(fig. 16)

Sample 

date

Tritium

(TU) R/Ra

4Heterr

(cm3STP/g)

Terrigenic

3He/4He

ratio

3Hetrit

(TU)

Apparent 

age

(year)

Apparent 

recharge 

year

Initial 

tritium

(TU)

Interpreted age 

category
Sources of Ground-Water Recharge 53

Monthly precipitation data are available for most of 

1963-84 (International Atomic Energy Agency, 2002). 

Mean annual 3H concentrations prior to 1963 and after 

1984 were estimated by correlation with the 

precipitation 3H record for Ottawa, Canada 

(International Atomic Energy Agency, 2002).

Data from figure 21 along with the 3H concentration of the water samples were used to place each well 

in one of three interpreted-age categories (table 11). 

Waters plotting near or above the precipitation line are 

dominantly modern and do not contain a substantial 

fraction of pre-bomb water. Waters with 3H concentrations less than about 2 TU are dominantly pre-bomb, 

containing less than about 20 percent modern water. 

Waters that plot below the precipitation line and have 

3H concentrations greater than about 2 TU may be 

either modern or a mixture of modern and pre-bomb 

water (note that modern water may plot below the precipitation line if it is a mixture of modern waters of different ages). Waters with elevated 4Heterr (greater than 

5x10-8 cm3STP/g) are distinguished from those with 

low 4Heterr (less than 5x10-8 cm3STP/g) in figure 21 

because initial 3H concentrations for waters with elevated 4Heterr are less certain. Initial 3H concentrations 

for waters with low 4Heterr have an uncertainty of less 

than about plus or minus 4 TU. Uncertainty in initial 

3H may be considerably greater for waters with high 

4Heterr. Waters from wells 1, 20, and 27, with apparent 

ages in the 1950s, were designated as dominantly prebomb or a mixture of modern and pre-bomb waters 

even though their initial 3H concentrations plot near the 

precipitation line. Because of high 4Heterr, initial 3H 

concentrations for waters from these three wells are 

highly uncertain and may actually be considerably less 

than precipitation 3H concentrations in the 1950s. 

Distributions of apparent 3H/3He age and interpreted-age category for water from public-supply wells 

in Salt Lake Valley are shown in figures 22 and 23, 

respectively. Apparent ages range from 3 years to more 

than 50 years. The two distributions are generally in 

good agreement. Both the apparent age and the fraction of pre-bomb water generally increase with distance 

from the mountain front on the east side of the valley. 

Generally, waters with apparent ages of less than 20 

Figure 21. Graph showing Tritium concentration in precipitation and the relation between initial tritium concentration and apparent recharge year for 

water sampled from the principal aquifer in Salt Lake Valley, Utah, 2000-01. 

0

20

40

60

80

100

120

140

160

<1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

APPARENT RECHARGE YEAR

Dominantly pre-bomb water

Modern water or a mixture of prebomb and modern water

Dominantly modern water

Precipitation

Approximate boundary between

samples with dominantly modern

water and samples comprised of

modern water or a mixture of

modern and pre-bomb water

Water from a well with low terrigenic

helium-4

Water from a well with high terrigenic

helium-4

INITIAL TRITIUM CONCENTRATION, IN TRITIUM UNITS
54 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

years are dominantly modern, waters with apparent 

ages of 20 to 40 years are modern or a mixture of 

modern and pre-bomb waters, and waters with apparent 

ages of more than 40 years are dominantly pre-bomb. 

Wells containing larger fractions of modern water 

should be more susceptible than those containing 

smaller fractions of modern water.

The 3H and 3He data are generally consistent 

with the Murray and Midvale zones being areas of particularly high susceptibility as a result of locally 

recharged water from the shallow unconfined aquifer 

entering the principal aquifer. Because locally 

recharged water follows relatively short flow pathways, 

wells containing such water should yield ages that are 

anomalously young compared to other wells located a 

similar distance from the mountain front. Both the 

apparent age and age-category distributions (figs. 22 

and 23) indicate that this is indeed the case for wells in 

the Murray zone. Water in the Midvale zone is not 

younger than water in immediately adjacent areas. 

However, if the boundary of the Midvale zone were 

extended to the north to include well 1 and to the southeast to include wells 21 and 81, the Midvale zone 

would clearly constitute an area of anomalously young 

water, indicative of local recharge.

Apparent ages of water in the primary recharge 

areas, secondary recharge areas, and discharge areas in 

the valley generally are consistent with the conceptual 

model for the ground-water flow system. Ages of 

ground water in the primary and secondary recharge 

areas are generally younger on the east side of the 

valley than on the west side (fig. 24), indicating that 

recharge rates are generally larger on the east side. On 

the east side of the valley, the youngest water is generally in the primary recharge area. Water becomes older 

with distance from the mountain front, the oldest water 

being in the discharge area (fig. 24). Outliers to this 

trend are the Sandy and Murray zones. Water from 

wells 29 and 44 in the Sandy zone has an apparent age 

more than 50 years even though the wells are in the 

secondary recharge area. Isotopic values are lighter in 

water from these wells than in those to the east (fig. 

17). As discussed in the “Dissolved Gas Recharge 

Temperatures” section of this report, wells in the Sandy 

zone may receive recharge from a different source than 

wells to the north and east. Water from wells 31, 77, 

and 80 in the Murray zone has an apparent age of 13 to 

18 years with no substantial component of pre-bomb 

water even though the wells are located in the discharge 

area.

On the west side of the valley, the median apparent age of water from wells in the secondary recharge 

and discharge areas is younger than that of water from 

wells located in the primary recharge area (fig. 24). 

This is probably because loss from canals diverted 

from the Jordan River and infiltration from irrigated 

fields are major components of recharge on the west 

side of the valley and the primary recharge area is 

located above most of these sources. All four of the 

sampled wells upgradient from the irrigation canals, 

three in the primary recharge area and one in the secondary recharge area, have dominantly pre-bomb water 

(fig. 23).

The apparent ages of the dominantly modern 

waters should not have a significant young-age bias 

and should approximate the flow-weighted mean age of 

water in the well. The age gradient indicated by wells 

with dominantly modern water can therefore be used to 

estimate a recharge rate by using the simple relation:

Q = vnA, (1)

where: 

Q is the recharge rate in the form of a volumetric 

flow rate; 

v is the average linear ground-water flow 

velocity; 

n is the average effective porosity; and 

A is the cross-sectional area normal to the flow 

direction. 

An approximate recharge rate was derived for the 

southeastern part of the valley where most of the 

public-supply wells are located. This includes the area 

from the mouth of Mill Creek Canyon southward to 

about 2 mi south of the mouth of Little Cottonwood 

Canyon. If wells in the Murray zone are excluded on 

the basis that they are likely drawing water from the 

shallow unconfined aquifer (fig. 22 and above discussion), the apparent ages of the dominantly modern 

waters increase from about 5 to about 20 years within 

approximately 2 mi of the mountain front. This yields 

a typical age gradient of about 7.5 years per mi, corresponding to an average linear ground-water flow velocity of about 1.9 ft/d. Freethey and others (1994) 

calculated local average linear velocities for the valley 

area extending outward from Big and Little Cottonwood Canyons by using measured and estimated water 

levels, hydraulic conductivity, and porosity. They 

reported that average linear velocity ranged from 
Sources of Ground-Water Recharge 55

Figure 22. Map showing Distribution of apparent tritium/helium-3 ages for water sampled from the principal aquifer in Salt Lake Valley, Utah, 2000-01.

Great

Salt

Lake

Apparent tritium/helium-3 age, in years

Less than 10 10 to 20 20 to 30 30 to 40 40 to 50 Greater than 50

EXPLANATION

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

UTAH COUNTY

18

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Boundary between secondary recharge area and discharge area

Boundary between primary and secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Public-supply well—Number is apparent age of water, in years

Dominantly clastic sedimentary rocks and carbonates

Dominantly quartzite with interbedded shales

Granitic intrusive rocks

Dominantly carbonates and volcanic rocks

Boundary of zone of principal aquifer referred to in

text

Parleys zone

Murray zone

Midvale zone

Sandy zone

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek

18

27

18

20

3

19

16

21 42

>50

24

26 14

5

30

22

31 31

>50

32

35

21

>50

45

>50

12

21

18

24

25

29

19 9

12 5

43

26

13

18 23 >50

45

27

22

16

13

45

19

24

>50

14

13

15

25

>50

31 36

>50

>50

47

48

16

19

25
56 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 23. Map showing Distribution of interpreted-age category for water sampled from the principal aquifer in Salt Lake Valley, Utah, 2000-01.

16

17

30

28

96

11

1

9

3

87

18

88

19 50

86

68

73 79

78 27

32

20

75

33

77

80

31

85 89

26 90

24

37

21

15

94

92

2

12

93

76 5

69

72 13

81 44

29

47

97 8

83

38 84

45

70

7

22

6

23

25

10 14

Big

Creek

Cottonwood

4

22

EXPLANATION

Interpreted-age categories for water from principal aquifer

Pre-bomb Modern or a mixture of modern and pre-bomb Modern

—Number is well identifier listed in table 11

Boundary between secondary recharge area and discharge area

Boundary between primary and secondary recharge areas

Approximate boundary of basin-fill deposits in Salt Lake Valley

Boundary of area where the dissolved-solids concentration in water from more than one well increased 20 percent

or more during 1988–2002

Boundary of zone of principal aquifer referred to in text

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

40°30'

40°45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

UTAH COUNTY

Parleys zone

Murray zone

Midvale zone

Sandy zone

Butterfield Creek

Creek Rose

Cr

Bingham

Barneys Creek

Coon

Creek

Parleys

Creek

City

Creek

Red Butte

Emigration

Creek

Mill Creek

Little

Cotton wood

Creek

Creek
Sources of Ground-Water Recharge 57

0.06 to 144 ft/d, with a median value of 3 ft/d. The 

average linear velocity derived from the age data is thus 

in general agreement with the results of Freethey and 

others (1994), albeit about 40 percent lower than their 

median value. 

Assuming v = 1.9 ft/d, n = 0.2 (this takes into 

account low flow in fine-grained lenses), an average 

saturated thickness of 330 ft (generally ranges from 

150 to 500 ft), and a north-south length of 10 mi (this 

assumes dominantly westward flow in the area of computation), the approximate recharge rate for the southeastern part of the valley is about 55,000 acre-ft/yr. 

This generally is consistent with, though slightly lower 

than, the recharge rate of 59,000 acre-ft/yr for this area 

in the ground-water flow model developed by Lambert 

(1995).

It should be recognized that the above estimation 

involves significant generalizations regarding the aquifer geometry and ground-water flow pathways. The 

purpose of the estimation is to determine whether the 

age data are roughly consistent with prior recharge estimates for the southeastern part of the valley (which 

they are). However, the age data do not rule out the 

possibility that MBR rates in this highly used part of 

the valley have been overestimated in prior studies. 

Manning (2002) took a considerably more rigorous 

approach in using the age distribution to constrain 

MBR rates, and concluded that the average MBR rate 

for the southeast area is probably 10 to 70 percent less 

than that in Lambert’s (1995) model. The age distribution and well-water temperature distribution were used 

to calibrate a three-dimensional finite-element model 

of heat and fluid transport in the southeastern part of 

Figure 24. Graph showing Range and distribution of apparent tritium/helium-3 age for water from the principal aquifer by area in Salt Lake Valley, Utah.

EAST SIDE OF VALLEY

Primary

recharge area

Secondary

recharge area

Discharge

area

WEST SIDE OF VALLEY

Primary

recharge area

Secondary

recharge area

Discharge

area

90th percentile

75th percentile

50th percentile (Median)

25th percentile

10th percentile

>50

40

30

20

10

APPARENT TRITIUM/HELIUM-3 AGE, IN YEARS

0
58 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

the valley that included both the valley and the mountain block. MBR rates greater than 90 percent of Lambert’s (1995) estimate were ruled out because they 

result in colder well-water temperatures than those 

observed. However, Manning’s (2002) model is highly 

generalized, also. Ideally, the tracer data presented in 

this report and the extensive hydrologic data utilized by 

Lambert (1995) should be used together to calibrate a 

three-dimensional heat and fluid flow model similar to 

that of Manning (2002), but spatially more refined. 

Such a model has the potential to place powerful constraints on MBR rates to the eastern part of Salt Lake 

Valley.

Chlorofluorocarbon Ages

CFCs are stable organic compounds that are 

solely anthropogenic. After their introduction in the 

1930s, atmospheric concentrations increased nearly 

exponentially until the 1990s. Because ground water 

becomes isolated from the atmosphere after entering 

the saturated zone, CFC concentrations in ground water 

can be correlated with atmospheric CFC concentrations 

at the time of recharge, providing a ground-water age. 

As with the 3H/3He method, the CFC method is typically used to date ground water younger than about 50 

years (modern water). CFCs generally are conservative 

in aerobic systems. Under anaerobic conditions, however, they may undergo microbial degradation. In populous areas, CFC contamination from leaking sewage 

systems and other sources is a common problem in the 

application of the CFC dating method. Details regarding the CFC dating method are published in Busenberg 

and Plummer (1992). 

Water samples for CFC analysis were collected 

from 31 wells, and the results are presented in table 12. 

All of the samples were collected during 2001 as part 

of this study. Apparent CFC ages were calculated by 

using the procedure described in Plummer and Busenberg (2000). The same Tr and recharge altitude used in 

the computation of the 3H/3He ages were used in the 

CFC age derivations. Apparent CFC ages determined 

for different samples collected from the same well in 

most cases differ by less than or equal to 3 years. An 

average value is also listed in table 12.

As mentioned in the “Tritium and Tritium/Helium-3 Ages” section of this report, the ground 

water sampled likely contains a mixture of water with 

different ages as a result of long open intervals in the 

public-supply wells. In some cases, CFC concentrations can be used by themselves to determine the fraction of pre-bomb water in a sample, assuming that the 

modern fraction is of a single age (simple binary mixture) (Plummer and Busenberg, 2000). This is done by 

considering the CFC concentrations relative to one 

another (for example, the CFC-113/CFC-12 ratio) in 

addition to the absolute CFC concentrations. The prebomb fraction of water in a sample also can be determined if CFC concentrations are measured in conjunction with 3H and 3He. As previously noted, the 

apparent 3H/3He age of modern/pre-bomb mixtures is 

very nearly that of the modern fraction. The apparent 

CFC age of modern/pre-bomb mixtures increases with 

the magnitude of the pre-bomb fraction, and should be 

older than the apparent 3H/3He age. Therefore, the prebomb fraction should be the fraction by which the CFC 

concentration must be divided to result in agreement 

between the apparent CFC age and the apparent 

3H/3He age. Finally, CFC concentrations near detection limits should indicate a sample almost entirely 

composed of pre-bomb water. 

Water samples with CFC concentrations greater 

than water equilibrated with the atmosphere in 2001 

are considered CFC contaminated. Contamination may 

occur in the aquifer or during sample collection. However, because established sampling protocols were 

carefully followed (see “Sample Collection” section of 

this report), the former is considered more likely. 

Water sampled from nearly half of the wells (14 of 31) 

is contaminated with at least 1 of the CFCs analyzed 

(table 12). Seven of the wells contained water contaminated with two of the three CFCs analyzed. The frequency of CFC-contaminated samples indicates the 

possibility that many of the water samples that appear 

uncontaminated with CFCs may actually be contaminated. A comparison of apparent 3H/3He ages and 

apparent CFC ages (fig. 25) indicates that this is the 

case. Uncontaminated samples containing all modern 

water or mixed modern/pre-bomb water should plot 

near or above the 1:1 line in figure 25, respectively, 

because apparent 3H/3He ages are biased to the 

modern-water component. Several of the samples plot 

well below the 1:1 line (apparent CFC age is younger 

than apparent 3H/3He age), indicating CFC contamination. It should be recognized that a sample plotting 

near the 1:1 line is not necessarily uncontaminated; it 

could be a contaminated sample containing a mixture 

of modern and pre-bomb water that would have plotted 

above the 1:1 line in the absence of contamination.
Sources of Ground-Water Recharge 59

Table 12. Chlorofluorocarbon age data for water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001—Continued

Well 

identifier

(fig. 5)

Measured concentration Apparent age Apparent recharge year

CFC-11

(pg/kg)

CFC-12

(pg/kg)

CFC-113

(pg/kg)

CFC-11

(years)

CFC-12

(years)

CFC-113

(years) CFC-11 CFC-12 CFC-113

1 253.4 344.2 204.3 30 13 C 1971.5 1988.5 C

1 254.8 365.4 203.3 30 11 C 1971.5 1990.5 C

1 284.9 356.2 213.2 29 12 C 1972 1989.5 C

1 264.4 355.3 206.9 30 12 C 1972 1990 C

2 686.9 186.6 28.9 17 24 22 1984.5 1977 1979

2 687.0 181.6 18.1 17 25 26 1984.5 1976.5 1975.5

2 683.4 169.9 27.4 17 26 23 1984.5 1975.5 1978.5

2 685.8 179.3 24.8 17 25 24 1985 1976 1978

3 2.4 3.1 0 51 53 46 1950.5 1948 1955

3 2.7 10.9 0 51 47 46 1950.5 1954 1955

3 1.9 2.0 0 51 55 46 1950 1946.5 1955

3 2.3 5.3 0 51 52 46 1950 1950 1955

4 8.7 15.5 4.4 47 44 35 1954 1957 1966

4 8.7 18.5 4.4 47 43 35 1954 1958.5 1966

4 9.0 23.7 3.7 47 41 36 1954 1960 1965

4 8.8 19.2 4.2 47 43 36 1954 1959 1966

5 10.2 5.5 9.5 47 51 30 1954.5 1950 1971

5 9.7 5.1 9.5 47 51 31 1954 1950 1970.5

5 9.3 5.0 6.1 47 52 34 1954 1949.5 1967.5

5 9.8 5.2 8.4 47 52 32 1954 1950 1970

6 10,907.2 2,397.2 35,592.7 C C C C C C

6 E 2,331.3 E C C C C C C

6 110,907.2 2,364 1 35,592.7 C C C C C C

7 2,300.4 345.7 22.7 C C 22 C C 1979

7 2,273.3 340.0 22.4 C C 22 C C 1979

7 2,235.9 335.3 22.5 C C 22 C C 1979

7 2,269.9 340.3 22.5 C C 22 C C 1979

8 2,719.6 274.3 175.5 C 18 C C 1983.5 C

8 2,682.9 267.7 167.5 C 18 C C 1983 C

8 2,820.1 305.8 187.5 C 15 C C 1986 C

8 2,740.8 282.6 176.8 C 17 C C 1984 C

9 1.1 2.5 0 52 54 46 1949 1947.5 1955

9 1.9 1.3 0 51 56 46 1950 1945.5 1955

9 1.6 13.6 0 52 45 46 1949.5 1956 1955

9 1.5 5.8 0 52 52 46 1950 1950 1955

10 706.5 271.7 79.9 8 12 12 1993.5 1989.5 1989.5

10 715.5 276.6 34.9 8 11 19 1993.5 1990 1982.5

10 706.5 276.8 75.0 8 11 12 1993.5 1990 1989

10 709.5 275.0 63.3 8 12 14 1994 1990 1987

11 7.0 6.9 7.3 48 49 31 1953.5 1952.5 1970.5

11 2.6 3.6 4.3 50 52 35 1951 1949 1966.5

Table 12. Chlorofluorocarbon age data for water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

[CFC-11, trichlorofluoromethane; CFC-12, dichlorodifluoromethane; CFC-113, trichlorotrifluoroethane; pg/kg, picogram per kilogram; C, contaminated; E, 

exceeds calibration range; bold lettering represents averages for multiple ampoules collected from each well]
60 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

11 3.8 4.9 .0 49 51 46 1952 1950.5 1955

11 4.5 5.1 3.9 49 51 37 1952 1951 1964

12 4,520.7 348.8 108.4 C 14 13 C 1987.5 1988.5

12 4,866.3 337.0 120.5 C 14 12 C 1987 1989.5

12 5,136.8 359.2 128.5 C 13 10 C 1988 1991

12 4,841.3 348.4 119.1 C 14 12 C 1988 1990

13 4,872.5 374.2 72.0 C C 14 C C 1987

13 1,889.2 342.6 71.4 C 6 14 C 1995 1987

13 2,039.5 343.5 73.6 C 6 14 C 1995.5 1987

13 2,933.7 353.4 72.3 C 6 14 C 1995 1987

14 366.2 236.6 23,551.8 24 15 C 1977 1986.5 C

14 370.6 240.4 23,797.6 24 15 C 1977.5 1986.5 C

14 366.8 239.4 23,435.6 24 15 C 1977 1986.5 C

14 367.8 238.8 23,595.0 24 15 C 1977 1987 C

15 1,100.0 361.8 105.9 C 7 11 C 1994.5 1990

15 1,096.4 362.4 100.0 C 6 12 C 1995.5 1989.5

15 1,118.4 323.3 102.8 C 12 12 C 1989 1989.5

15 1,104.9 349.2 102.9 C 8 12 C 1993 1990

16 491.8 125.7 29.6 21 28 21 1980 1973.5 1980

16 494.8 132.2 28.4 21 27 21 1980 1974 1980

16 502.6 128.9 28.6 21 27 21 1980.5 1974 1980

16 496.4 128.9 28.9 21 28 21 1980 1974 1980

17 E 4421.0 E C C C C C C

17 E 4203.0 E C C C C C C

17 E 4312.0 E C C C C C C

18 467.6 204.3 18.1 17 16 23 1984 1985 1978.5

18 466.4 204.3 19.0 17 16 23 1984 1985 1978.5

18 456.1 187.7 16.6 18 18 23 1983.5 1983 1978

18 463.4 198.8 17.9 18 17 23 1984 1984 1978

19 15.8 132.8 0 44 26 46 1957 1975.5 1955

19 17.7 122.0 0 44 26 46 1957.5 1975 1955

19 18.2 122.3 0 44 26 46 1957.5 1975 1955

19 17.2 125.7 0 44 26 46 1957 1975 1955

20 1,348.5 748.5 7,659.1 C C C C C C

20 1,345.0 732.6 7,539.3 C C C C C C

20 1,335.6 763.7 7,437.0 C C C C C C

20 1,343.0 748.3 7,545.1 C C C C C C

21 8,771.2 350.9 17.7 C 1 25 C 2000 1976

21 8,827.3 356.4 18.8 C 0 25 C 2001 1976.5

21 8,947.5 342.3 17.9 C 7 25 C 1994 1976

21 8,848.7 349.9 18.2 C 3 25 C 1999 1976

22 583.5 357.5 27.6 15 C 21 1986.5 C 1980.5

22 568.0 384.4 25.8 15 C 21 1986 C 1980

22 585.9 343.9 26.5 15 C 21 1986.5 C 1980.5

Table 12. Chlorofluorocarbon age data for water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001—Continued

Well 

identifier

(fig. 5)

Measured concentration Apparent age Apparent recharge year

CFC-11

(pg/kg)

CFC-12

(pg/kg)

CFC-113

(pg/kg)

CFC-11

(years)

CFC-12

(years)

CFC-113

(years) CFC-11 CFC-12 CFC-113
Sources of Ground-Water Recharge 61

22 579.2 361.9 26.6 15 C 21 1986 C 1980

23 3.2 3.3 0 50 52 46 1951.5 1949 1955

23 2.4 3.9 0 50 52 46 1951 1949.5 1955

23 3.1 9.8 0 50 46 46 1951.5 1955 1955

23 2.9 5.7 0 50 50 46 1951 1951 1955

24 10.3 7.6 2.6 46 48 38 1955.5 1953 1963.5

24 12.0 3.7 1.6 45 52 41 1956 1949.5 1960.5

24 12.0 3.2 5.6 45 52 32 1956 1949 1969

24 11.4 4.8 3.3 45 51 37 1956 1951 1964

25 1.5 2.0 46.7 51 54 16 1950 1947 1985

25 1.4 1.9 43.1 51 54 17 1950 1947 1984.5

25 1.4 .9 42.0 52 57 17 1949.5 1944.5 1984

25 1.5 1.6 43.9 52 55 17 1950 1946 1985

26 74.3 205.3 0 37 21 46 1964.5 1980.5 1955

26 74.2 174.7 0 37 24 46 1964.5 1977.5 1955

26 73.5 165.1 0 37 25 46 1964.5 1976.5 1955

26 74.0 181.7 0 37 23 46 1965 1978 1955

27 340.2 494.0 3.5 28 C 38 1973.5 C 1963

27 339.5 511.2 4.3 28 C 37 1973.5 C 1964.5

27 358.1 514.5 5.1 27 C 35 1974 C 1966

27 345.9 506.6 4.3 28 C 37 1974 C 1965

28 8.7 24.5 3.6 47 40 36 1954.5 1961 1965

28 8.0 23.1 3.6 47 41 36 1954 1960.5 1965.5

28 8.4 17.3 4.4 47 43 35 1954.5 1958.5 1966.5

28 8.4 21.6 3.9 47 41 36 1954 1960 1966

29 5.8 1.6 2.2 48 55 39 1953.5 1946.5 1962

29 5.1 6.0 0 48 50 46 1953 1951.5 1955

29 5.0 22.1 0 48 41 46 1953 1960.5 1955

29 5.3 9.9 .7 48 49 44 1953 1953 1957

30 92.6 219.5 14.1 35 18 26 1966.5 1983 1975

30 89.7 204.8 15.2 35 20 26 1966 1981.5 1975.5

30 89.4 201.7 15.1 35 20 26 1966 1981.5 1975.5

30 91.7 199.3 14.2 35 20 26 1966 1981 1975

30 90.8 206.3 14.6 35 20 26 1966 1982 1975

31 2,195.8 526.2 1,797.8 C C C C C C

31 2,295.4 556.8 1,822.2 C C C C C C

31 5,553.3 531.6 1,520.2 C C C C C C

31 3,348.2 538.2 1,713.4 C C C C C C

1Average excludes samples that are contaminated or exceed calibration range.

Table 12. Chlorofluorocarbon age data for water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001—Continued

Well 

identifier

(fig. 5)

Measured concentration Apparent age Apparent recharge year

CFC-11

(pg/kg)

CFC-12

(pg/kg)

CFC-113

(pg/kg)

CFC-11

(years)

CFC-12

(years)

CFC-113

(years) CFC-11 CFC-12 CFC-113
62 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

The frequency of CFC contamination significantly compromises the reliability of modern ages 

determined by the CFC method. Another consequence 

of the contamination is that determination of the prebomb fraction from CFC-concentration ratios generally 

is not possible. As a result of the general unreliability 

of the modern ages, pre-bomb fractions were not computed by adjusting apparent CFC ages to match apparent 3H/3He ages. CFC concentrations indicating 

recharge prior to 1955, however, are still useful in evaluating well susceptibility because wells that contain 

water with very low CFC concentrations likely contain 

a high fraction of pre-bomb water. Seven of the wells 

have water with concentrations of two or more CFCs 

that indicate recharge before 1955. Of these, all but 

one (well 5) also contains dominantly pre-bomb water 

based on 3H concentrations. General agreement 

between the CFC and 3H data sets regarding the occurrence of pre-bomb water is further indicated by the fact 

that all but two of the wells containing dominantly prebomb water based on 3H have apparent CFC recharge 

years in or prior to the mid-1960s. These apparent 

CFC ages are consistent with simple bimodal mixtures 

containing greater than 80 percent pre-bomb water, 

assuming the modern component is of a single age.

Contamination levels of CFCs also are potentially useful in gauging well susceptibility because 

wells with CFC-contaminated water most likely contain an appreciable component of modern water 

(assuming contamination did not occur during sampling). This generally is supported by the interpretedage categories derived from initial 3H concentrations. 

Of the 14 wells that contain water contaminated with at 

least 1 CFC, 8 have dominantly modern water, 4 have 

modern water or a mixture of modern and pre-bomb 

waters, and 2 have dominantly pre-bomb water. 

Figure 25. Graph showing Apparent chlorofluorocarbon age and apparent tritium/helium-3 age for water sampled from selected public-supply wells in 

Salt Lake Valley, Utah.

0

5

10

15

20

25

30

35

40

45

50

55

0 5 10 15 20 25 30 35 40 45 50 >50

APPARENT TRITIUM/HELIUM-3 AGE, IN YEARS

CFC-11

CFC-12

CFC-113

APPARENT CHLOROFLUOROCARBON AGE, IN YEARS
Relation Between Ground-Water Quality and Sources of Recharge 63

RELATION BETWEEN GROUND-WATER 

QUALITY AND SOURCES OF RECHARGE

Pesticides and (or) VOCs were detected, mostly 

at very low concentrations, in water from 23 of the 31 

public-supply wells sampled. Produced and used exclusively by humans, pesticides and VOCs are known as 

anthropogenic compounds. Although measured concentrations of these compounds are not a health concern, their widespread occurrence indicates the 

presence of water young enough to be affected by 

humans in much of the principal aquifer. Detection of 

these compounds in water from a well indicates the 

possibility that water with higher concentrations may 

enter the well in the near future. Wells with water samples in which low levels of VOCs (mainly chloroform) 

and pesticides (mainly atrazine and (or) its degradation 

products) were measured at concentrations greater than 

laboratory or method reporting levels (LRLs or MRLs) 

are shown in figure 26. Also shown are wells that contain water with nitrate concentrations greater than 2 

mg/L, an estimated background level. The source of 

nitrate concentrations above the background level is 

probably the application of fertilizers and leaking or 

improperly functioning septic systems and sewer pipes 

in the valley. Wells with water that contains anthropogenic compounds above reporting levels and (or) 

nitrate concentrations above 2 mg/L are referred to 

below as “affected wells.” Eighteen of the 31 publicsupply wells sampled (58 percent) are affected wells. 

The fact that a well is affected confirms that it has a 

reasonably high level of susceptibility. 

The presence of anthropogenic compounds at 

concentrations above reporting levels and elevated 

nitrate concentrations in the principal aquifer (fig. 26) 

generally is not well correlated with the distribution of 

minimum MFR (fig. 18) and minimum MBR (fig. 20) 

fractions of water derived from δ18O and Tr data, 

respectively. Many of the affected wells have high 

MFR and MBR fractions of water, indicating that wells 

containing even small amounts of valley recharge 

(probably 10 to 20 percent) are reasonably susceptible. Only two of the wells sampled for anthropogenic 

compounds fall into the highest susceptibility group 

according to both δ18O and Tr data: well 31 in the 

Murray zone and well 20 in the Midvale zone. Well 31 

is affected, but well 20 is not. It should be noted, however, that δ18O data indicate that the Midvale zone may 

extend farther to the north and southeast to include 

wells 1 and 21, and both of these wells are indeed 

affected. Therefore, the minimum MFR and MBR 

fractions may still be useful tools for identifying those 

highest susceptibility areas where wells are clearly 

drawing in a substantial amount of valley recharge.

The presence of anthropogenic compounds and 

elevated nitrate concentrations in the principal aquifer 

(fig. 26) is very well correlated with the distribution of 

interpreted-age categories (fig. 23 and 26). Nearly all 

of the affected wells (17 of 18) have either dominantly 

modern water or a mixture of modern and pre-bomb 

waters, meaning that they probably contain more than 

20 percent modern water. Well 23 is the only affected 

well that contains dominantly pre-bomb water. Well 23 

is also the only affected well that does not contain 

anthropogenic compounds above reporting levels. 

Most of the unaffected wells (10 of 13) contain dominantly pre-bomb water and thus contain little modern 

water (less than 20 percent). All of the wells (10 of 10) 

with dominantly modern water are affected. Seventy 

percent (7 of 10) of the wells with dominantly modern 

or a mixture of modern and pre-bomb waters are 

affected. Nine percent (1 of 11) of the wells with dominantly pre-bomb water are affected. These results 

indicate that much of the modern ground water in Salt 

Lake Valley contains anthropogenic-compound concentrations above reporting levels or nitrate concentrations greater than the estimated background level of 2 

mg/L. As expected, pre-bomb water generally is free 

of these human effects. Therefore, 3H/3He data appear 

to be of great value in evaluating well susceptibility in 

the principal aquifer.

Wells that contain water contaminated with at 

least one CFC and with CFC concentrations indicative 

of recharge prior to 1955 (low CFC concentrations) are 

also shown in figure 26. Eleven of the 14 wells that 

contain CFC-contaminated water also are affected 

wells, indicating that the presence of CFC contamination may be a relatively useful indicator of high susceptibility. Six of the seven wells that contain water with 

low CFC concentrations are not affected, indicating 

that low CFC concentrations may be a reliable indicator of low susceptibility. Well 23 is the single affected 

well (elevated nitrate concentrations) that has water 

with low CFC concentrations (indicative of recharge 

prior to 1955). This is consistent with the 3H/3He 

results that indicate dominantly pre-bomb water from 

well 23.
64 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 26. Map showing Interpreted-age category, chlorofluorocarbon, anthropogenic-compound, and nitrate information for water sampled from 31 

public-supply wells in Salt Lake Valley, Utah, 2001.

14 10

25

24

23

6

22

7

29

8

13

4

21

5

20 15 2 12

26

31

27

1

3

9

11

19

18

17

16

30

28

22

EXPLANATION

Interpreted-age categories of water from principal aquifer

Dominantly pre-bomb

Modern or a mixture of modern and pre-bomb

Dominantly modern

Base from U.S. Geological Survey digital line graph data, 1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

40°30'

40°45'

Jordan

River

0 3 6 KILOMETERS

0 3 6 MILES

112°07'30" 111°48'

SALT LAKE COUNTY

UTAH COUNTY

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill

deposits in Salt Lake Valley

Public-supply well sampled as part of this study—Number is well

identifier

Apparent chlorofluorocarbon age of water is pre-1955

Water is contaminated with at least one chlorofluorocarbon

Volatile organic compound or pesticide detected in water at concentrations above laboratory reporting levels or method detection levels

Nitrate concentration of water greater than 2 milligrams per liter

Parleys zone

Murray zone

Midvale zone

Sandy zone

Butterfield Creek

Creek Rose

Cr

Bingham

Coon

Creek

Parleys

Creek

City

Creek

Red

Butte

Emigration

Creek

Mill Creek

Big

Creek

Cottonwood

Little

Cotton wood

Creek

Creek
Relation Between Ground-Water Quality and Sources of Recharge 65

The relation between the occurrence and concentration of anthropogenic compounds, nitrate, and other 

variables was examined with the Spearman rank correlation test (Helsel and Hirsch, 1992, p. 209-218). The 

correlation coefficient (rho) varies from 1 to -1 and 

describes the strength of the correlation. Values closer 

to 1 indicate a positive correlation, values closer to -1 

indicate an inverse correlation, and values closer to 0 

indicate no correlation. The p-value (probability of no 

correlation) was used to evaluate the significance of the 

correlation. P-values less than 0.10 are considered statistically significant, whereas larger p-values indicate a 

greater probability of no correlation.

The number of anthropogenic compounds 

detected (includes estimated concentrations less than 

LRL or MRLs) in water sampled from each well is 

inversely correlated with the apparent 3H/3He age (fig. 

27). Anthropogenic compounds were not detected in 

water with an apparent age older than 50 years, except 

for water from well 25. Interpretation of the trace 

amount of atrazine detected in water from this well 

(0.004 μg/L) and application to the aquifer as a whole 

should be done with caution because of the large depth 

to the well openings (636-1,202 ft below land surface). 

Nitrate concentration in water from the 31 sampled 

public-supply wells is correlated with many factors, 

such as depth to the top of the well’s open interval, the 

δ18O ratio of the water, the apparent age of the water 

determined from the 3H/3He method, and the number 

of anthropogenic compounds detected in water per 

well. Generally, nitrate concentration in water from the 

sampled wells increased as the depth to the top of the 

well’s open interval became shallower; as the δ18O 

ratios became heavier and, therefore, the MFR fraction 

became smaller; as the apparent age of the water 

became younger; and as the number of anthropogenic 

compounds detected in water per well increased (fig. 

27). On the basis of these correlations, nitrate concentration in water from many of the wells is related to the 

occurrence of modern valley recharge.

The concentration of anthropogenic compounds 

in a water sample was considered to be the sum of all 

VOC and pesticide compounds detected. For most 

wells where VOC or pesticide compounds were 

detected in the water, total concentrations decreased as 

the apparent 3H/3He age increased (fig. 28). Generally, 

wells with dominantly pre-bomb water had very low or 

undetected total concentrations of anthropogenic compounds. All of the samples that contained mostly 

modern water contained at least one anthropogenic 

compound. Anomalously high concentrations of chloroform, bromodichloromethane, and chlorodibromomethane were measured in water samples from 

wells 8 and 13, likely the result of chlorinated surface 

water occasionally injected into the principal aquifer at 

these wells as artificial recharge. Note, however, that 

these wells are only used as injection wells for a short 

duration each spring, and the injected water constitutes 

a very small fraction of the total volume removed from 

these wells since the initiation of the artificial recharge 

program in 2000. Well 26 is the only well containing 

modern or a mixture of pre-bomb and modern waters in 

which no anthropogenic compounds were detected. 

Total concentration of VOCs and pesticides in 

water generally decreased as the depth to the top of the 

open interval in the well became deeper (fig. 28). Artesian conditions exist at all six of the wells where the 

top of the open interval is less than 150 ft below land 

surface. Anthropogenic compounds or CFC contamination occur in water from five of these wells, indicating 

that wells with shallow openings are susceptible to 

receiving recently recharged water despite the natural 

upward gradient in a discharge area. Human activities 

in the adjacent recharge area may be the source of these 

compounds in water from wells 10, 14, and 30. Wells 

27 and 31 are farther from the primary recharge area 

and CFC contamination in water samples from these 

wells may be the result of a reversal in the water-level 

gradient near the wells.

Areas with an increase in dissolved-solids concentration greater than 20 percent from 1988-92 to 

1998-2002 (figs. 7 and 8) generally correspond to areas 

with relatively large components of modern water (fig. 

23), except for near the Jordan River west of the 

Murray zone and in the Sandy zone. Although in the 

discharge area, water sampled from wells 1 and 27 contained tritium and CFC contamination indicating 

mixing with a modern component of water. Withdrawals from the principal aquifer in the area may have 

allowed recently recharged water to move downward 

into the aquifer in the vicinity of these wells. Ground 

water with dissolved-solids concentrations greater than 

500 mg/L has extended farther into the Sandy zone 

during the last decade. As discussed in previous sections, water in this area is isotopically lighter than 

water from the Jordan River, has a warmer recharge 

temperature than ground water to the east, and was 

recharged before the 1950s. Lateral movement of
66 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Figure 27. Graphs showing Relation among the occurrence of anthropogenic compounds detected, nitrate concentration, and other factors for water 

sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001.

EXPLANATION

DELTA OXYGEN-18, IN PER MIL

-10

-11

-12

-13

-16

-17

-14

-15

-18

700

600

500

300

100

0

200

400

p = 0.0002

rho = -0.679

APPARENT TRITIUM/HELIUM-3 AGE,

IN YEARS

0 2 3 4 5 6 10 1

50

30

10

0

20

40

>50

35

15

5

25

45

789 0 23456 1 7

Discharge area

Secondary recharge area

Primary recharge area

Probability of no correlation

Correlation coefficient

p = 0.0018

rho = -0.570

50

30

10

0

20

40

>50

35

15

5

25

45

APPARENT TRITIUM/HELIUM-3 AGE,

IN YEARS

8

4

0

6

10

9

5

1

7

11

3

2

NITRATE CONCENTRATION, IN MILLIGRAMS PER LITER

0 23456 1 7

DEPTH TO TOP OF OPEN

INTERVAL IN WELL, IN FEET

p = 0.0002

rho = 0.672

p = 0.0077

rho = -0.486

0 23456 1 7

0 2 1 34567

p = 0.0001

rho = 0.719

p

rho

NITRATE CONCENTRATION, IN MILLIGRAMS PER LITER

NITRATE CONCENTRATION, IN MILLIGRAMS PER LITER

NUMBER OF ANTHROPOGENIC COMPOUNDS DETECTED NITRATE CONCENTRATION, IN MILLIGRAMS PER LITER

NUMBER OF ANTHROPOGENIC

COMPOUNDS DETECTED
Relation Between Ground-Water Quality and Sources of Recharge 67

Figure 28. Graphs showing Relation of total concentration of volatile organic compounds and pesticides to apparent tritium/helium-3 age and to depth to 

top of open interval for water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001.

100

Discharge area

Secondary recharge area

Primary recharge area

10

1

0.1

0.01

0.001

TOTAL VOLATILE ORGANIC COMPOUND AND PESTICIDE CONCENTRATION, IN MICROGRAMS PER LITER

Dominantly pre-bomb water

Modern water or a mixture of pre-bomb and modern water

Dominantly modern water

Number is well identifier

0 10 20 30 40 > 50

APPARENT TRITIUM/HELIUM-3 AGE, IN YEARS

100

10

1

0.1

0.01

0.001

0 100 200 300 400 500 600 700

Relatively high trihalomethane concentration

caused by injection of treated surface water

at these wells

No VOC or pesticide detected

3, 9, 23,

24, 28, 29

Relatively high trihalomethane concentration

caused by injection of treated surface water

at these wells

No VOC or pesticide detected

DEPTH TO TOP OF OPEN INTERVAL IN WELL, IN FEET

13

8

17 16

12 2

18

30

31

15 22

6 7

19

4

14 10

21

5

26 27

20

11

1

13

8

17 16

12 2

18

30

31

15 22

7 6

19

4

14

10

21

5

20

1

25

26 27 11 28 29 23 24 9 3

25

Blue

Green

Red

6

5

15
68 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

ground water with higher dissolved-solids 

concentrations from the west and southwest may have 

been induced by withdrawals in the area.

SUMMARY

Ground water supplies about one-third of the 

water used by the public in Salt Lake Valley, Utah. The 

purpose of this study is to evaluate the occurrence and 

distribution of natural and anthropogenic compounds in 

ground water used for public supply in the valley and to 

determine the general sources of recharge to the principal aquifer. Water samples were collected from 31 

public-supply wells. Water-quality data for the wells 

consist of analyses of field parameters, major ions, 

trace elements, radon, nutrients, dissolved organic carbon, methylene blue active substances, pesticides, and 

volatile organic compounds. 

Dissolved-solids concentration ranged from 157 

to 1,280 mg/L in water from the 31 public-supply 

wells. Comparison of water sampled from the principal 

aquifer during 1988-92 and 1998-2002 shows a reduction in the area where the dissolved-solids concentration is less than 500 mg/L. Ground water with a 

dissolved-solids concentration less than 500 mg/L in an 

area extending to the northwest, past the Jordan River, 

receded to the southeast likely because of pumping in 

the area and in upgradient areas to the southeast. Dissolved-arsenic concentrations in water from five wells 

exceeded the drinking-water maximum contaminant 

level of 10 μg/L. Water from wells in much of the western part of the study area generally had higher arsenic 

concentrations than water from other areas. Nitrate 

concentration in water sampled from 12 of the 31 

public-supply wells was higher than an estimated background level of 2 mg/L, indicating a likely human 

influence. 

At least one pesticide or pesticide degradation 

product was detected at concentrations much lower 

than year 2002 U.S. Environmental Protection Agency 

drinking-water standards in water from 13 of the 31 

wells sampled. The relatively high detection frequency 

of atrazine in water samples from the west side of the 

valley may be the result of application in agricultural or 

industrial areas that also are recharge areas for the aquifer.

The most frequently detected volatile organic 

compounds were chloroform (54.8 percent), bromodichloromethane (35.5 percent), and 1,1,1-trichloroethane (19.4 percent). The widespread occurrence of 

chloroform and bromodichloromethane in deeper 

ground water is likely a result of the recharge of chlorinated public-supply water used to irrigate lawns and 

gardens in residential areas of Salt Lake Valley. 

Environmental tracers were used to determine 

the sources of recharge to the principal aquifer used for 

public supply in the valley. The stable isotopes of water 

(deuterium and oxygen-18) and recharge temperatures 

computed from dissolved noble gases in the ground 

water were used to differentiate between mountain and 

valley recharge. Tritium, helium-3, and chlorofluorocarbons were used to identify and date ground water 

recharged within the past 50 years. Because the local 

population resides in the valley, along with most of the 

local industry, water that enters the ground-water 

system in the valley has a greater likelihood of containing anthropogenic compounds than does mountainblock recharge.

Maximum recharge temperatures in the eastern 

part of the valley generally are below the range of 

valley water-table temperatures indicating that mountain-block recharge must constitute a substantial fraction of recharge to the principal aquifer in this area. 

Together, the recharge temperature and stable-isotope 

data define two zones that contain large fractions of 

valley recharge on the east side of the valley.

To determine if a sample contains a substantial 

fraction of pre-bomb water (more than 50 years old) 

the initial tritium concentration of each sample (measured tritium plus measured tritiogenic helium-3) is 

compared to that of local precipitation at the apparent 

time of recharge. Three interpreted-age categories were 

determined for water from the sampled wells: (1) dominantly pre-bomb; (2) dominantly modern; and (3) 

modern or a mixture of pre-bomb and modern. Apparent tritium/helium-3 ages range from 3 years to more 

than 50 years. Ground water on the east side of the 

valley generally becomes older with distance from the 

mountain front, the oldest water being in the discharge 

area. Generally, wells with apparent ages for water less 

than 20 years contain dominantly modern water, wells 

with apparent ages for water of 20-40 years contain 

modern water or a mixture of modern and pre-bomb 

waters, and wells with apparent ages for water greater 

than 40 years contain dominantly pre-bomb water.
References Cited 69

Chlorofluorocarbon-age data were collected for 

the 31 wells sampled during this study. Water sampled 

from nearly half of the wells was contaminated with at 

least 1 of the CFCs analyzed. Contamination levels of 

CFCs are potentially useful in gauging well susceptibility because wells with CFC-contaminated water 

most likely contain an appreciable component of 

modern water.

The presence of anthropogenic compounds at 

concentrations above reporting levels and elevated 

nitrate concentrations (affected wells) in the principal 

aquifer is very well correlated with the distribution of 

interpreted-age categories. All of the wells (10 of 10) 

with dominantly modern water are affected. Seventy 

percent (7 of 10) of the wells with dominantly modern 

or a mixture of modern and pre-bomb waters are 

affected. Only 9 percent (1 of 11) of the wells with 

dominantly pre-bomb water are affected. Both the 

number and total concentration of anthropogenic compounds detected in water sampled from each well is 

inversely correlated with the apparent 3H/3He age. 

Anthropogenic compounds were not detected in water 

with an apparent age of more than 50 years, except for 

water from one well. All of the samples made up 

mostly of modern water contained at least one anthropogenic compound.

Areas with an increase in dissolved-solids concentration greater than 20 percent from 1988-92 to 

1998-2002 generally correspond to areas with relatively large components of modern water. Although in 

the discharge area, water sampled from two wells did 

contain tritium and CFC contamination, an indication 

of mixing with a modern component of water. Withdrawals from the principal aquifer in the area may have 

allowed recently recharged water to move downward 

into the aquifer in the vicinity of these wells.

REFERENCES CITED

American Society for Testing and Materials, 1996, Annual 

book of ASTM standards, section 11, Water and environmental technology: American Society for Testing 

and Materials, v. 11.02, D5072-92, p. 674-676.

Anderson, P.B., Susong, D.D., Wold, S.R., Heilweil, V.M., 

and Baskin, R.L., 1994, Hydrogeology of recharge 

areas and water quality of the principal aquifers along 

the Wasatch Front and adjacent areas, Utah: U.S. Geological Survey Water-Resources Investigations Report 

93-4221, 74 p.

Barbash, J.E., Thelin, G.P., Kolpin, D.W., and Gilliom, R.J., 

1999, Distribution of major herbicides in ground water 

of the United States: U.S. Geological Survey WaterResources Investigations Report 98-4245, 57 p.

Bayer, R., Schlosser, P., Bönisch, G., Rupp, H., Zaucker, F., 

and Zimmek, G., 1989, Performance and blank components of a mass spectrometric system for routine measurement of helium isotopes and tritium by the 3He 

ingrowth method, in Sitzungsberichte der Heidelberger 

Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Klasse: Heidelberg, Springer Verlag, 

v. 5, p. 241-279.

Brenton, R.W., and Arnett, T.L., 1993, Methods of analysis 

by the U.S. Geological Survey National Water-Quality 

Laboratory—Determination of dissolved organic 

carbon by UV-promoted persulfate oxidation and infrared spectrometry: U.S. Geological Survey Open-File 

Report 92-480, 12 p.

Burkhardt, M.R., Cinotto, P.J., Frahm, G.W., Woodworth, 

M.T., and Pritt, J.W., 1995, Methods of analysis by the 

U.S. Geological Survey National Water-Quality Laboratory—Determination of methylene blue active substances by spectrophotometry: U.S. Geological Survey 

Open-File Report 95–189, 16 p.

Busenberg, E., and Plummer, L.N., 1992, Use of chlorofluorocarbons (CCl3F and CCl2F2) as hydrologic tracers 

and age-dating tools: Example–The alluvium and terrace system of central Oklahoma: Water Resources 

Research, v. 28, p. 2257–2284.

Childress, C.J., Foreman, W.T., Connor, B.F., and Maloney, 

T.J., 1999, New reporting procedures based on longterm method detection levels and some considerations 

for interpretations of water-quality data provided by the 

U.S. Geological Survey National Water-Quality Laboratory: U.S. Geological Survey Open-File Report 99-

193, 19 p.

Conner, B.F., Rose, D.L., Noriega, M.C., Murtagh, L.K., and 

Abney, S.R., 1998, Methods of analysis by the U.S. 

Geological Survey National Water-Quality Laboratory—Determination of 86 volatile organic compounds 

in water by gas chromatography/mass spectrometry, 

including detections less than reporting limits: U.S. 

Geological Survey Open-File Report 97-829, 78 p.

Coplen, T.B., Wildman, J.D., and Chen, J., 1991, Improvements in the gaseous hydrogen-water equilibration 

technique for hydrogen isotope ratio analysis: Analytical Chemistry, v. 63, no. 9, p. 910-912.

Daly, C., and Taylor, G., 1998, Utah average monthly or 

annual precipitation, 1961-90: Water and Climate 

Center of the Natural Resources Conservation Service, 

accessed June 23, 2003, at URL 

http://www.ocs.orst.edu/pub/maps/Precipitation/Total/States/UT/ut.gif
70 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Epstein, S., and Mayeda, T., 1953, Variation of O-18 content 

of water from natural sources: Geochemica et Cosmochimica Acta, v. 4, p. 213-224.

Faires, L.M., 1993, Methods of analysis by the U.S. Geological Survey National Water-Quality Laboratory—Determination of metals in water by inductively coupled 

plasma-mass spectrometry: U.S. Geological Survey 

Open-File Report 92-634, 28 p.

Fenneman, N.M., 1931, Physiography of the Western United 

States: New York, McGraw-Hill, 534 p.

Fishman, M.J., ed., 1993, Methods of analysis by the U.S. 

Geological Survey National Water-Quality Laboratory—Determination of inorganic and organic constituents in water and fluvial sediments: U.S. Geological 

Survey Open-File Report 93-125, 217 p.

Fishman, M.J., and Friedman, L.C., 1989, Methods for 

determination of inorganic substances in water and fluvial sediments: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 5, chap. A1, 545 

p.

Freethey, G.W., Spangler, L.E., and Monheiser, W.J., 1994, 

Determination of hydrologic properties needed to calculate average linear velocity and travel time of ground 

water in the principal aquifer underlying the southeastern part of Salt Lake Valley, Utah: U.S. Geological 

Survey Water-Resources Investigations Report 92-

4085, 30 p.

Furlong, E.T., Anderson, B.D., Werner, S.L., Soliven, P.P., 

Coffey, L.J., and Burkhardt, M.R., 2001, Methods of 

analysis by the U.S. Geological Survey National WaterQuality Laboratory—Determination of pesticides in 

water by graphitized carbon-based solid-phase extraction and high-performance liquid chromatography/mass 

spectrometry: U.S. Geological Survey Water-Resources 

Investigations Report 01-4134, 73 p.

Halberg, G.R., and Keeney, D.R., 1993, Nitrate, in Alley, 

W.M., ed., Regional ground-water quality: New York, 

Van Nostrand Reinhold, p. 297-322.

Helsel, D.R., and Hirsch, R.M., 1992, Statistical methods in 

water resources: New York, Elsevier Science Publishers, 522 p.

Hely, A.G., Mower, R.W., and Harr, C.A., 1971, Water 

resources of Salt Lake County, Utah: Utah Department 

of Natural Resources Technical Publication No. 21, 244 

p.

Holocher, J., Matta, V., Aeschbach-Hertig, W., Beyerle, U., 

Hofer, M., Peeters, F., and Kipfer, R., 2001, Noble gas 

and major element constraints on the water dynamics in 

an alpine floodplain: Ground Water, v. 39, p. 841-852.

International Atomic Energy Agency, 2002, Isotope Hydrology Section database, accessed January 13, 2003, at 

URL http://isohis.iaea.org

Koterba, M.T., Wilde, F.D., and Lapham, W.W., 1995, 

Ground-water data-collection protocols and procedures 

for the National Water-Quality Assessment program: 

Collection and documentation of water-quality samples 

and related data: U.S. Geological Survey Open-File 

Report 95-399, 113 p.

Lambert, P.M., 1995, Numerical simulation of ground-water 

flow in basin-fill material in Salt Lake Valley, Utah: 

Utah Department of Natural Resources Technical Publication No. 110-B, 58 p.

Maloszewski, P., and Zuber, A., 1982, Determining the turnover time of groundwater systems with the aid of environmental tracers: Journal of Hydrology, v. 57, p. 207-

231.

Manning, A.H., 2002, Using noble gas tracers to investigate 

mountain-block recharge to an intermountain basin: 

Salt Lake City, University of Utah, Dept. of Geology 

and Geophysics, Ph.D. thesis, 187 p.

Manning, A.H., and Solomon, D.K., 2003, Using noble 

gases to investigate mountain-front recharge: Journal of 

Hydrology, v. 275, p. 194-207.

Maurer, D.K., Plume, R.W., Thomas, J.M., and Johnson, 

A.K., 1996, Water resources and effects of changes in 

ground-water use along the Carlin Trend, North-Central 

Nevada: U.S. Geological Survey Water-Resources 

Investigations Report 96-4134, 146 p.

Mayo, A.L., and Loucks, M.D., 1995, Solute and isotopic 

geochemistry and ground water flow in the central 

Wasatch Range, Utah: Journal of Hydrology, v. 172, p. 

31-59. 

Mazor, E., 1991, Applied chemical and isotopic groundwater 

hydrology: New York, Halsted Press, 273 p.

Parry, W.T., Forster, C.B., Solomon, D.K., and James, L.P., 

2000, Ownership of mine-tunnel discharge: Ground 

Water, v. 38, p. 487-496.

Patton, C.J., and Truitt, E.P., 1992, Methods of analysis by 

the U.S. Geological Survey National Water-Quality 

Laboratory—Determination of total phosphorus by a 

Kjeldahl digestion method and an automated colorimetric finish that includes dialysis: U.S. Geological Survey 

Open-File Report 92-146, 39 p.

Plummer, L.N., and Friedman, L.C., 1999, Tracing and 

dating young ground water: U.S. Geological Survey 

Fact Sheet FS-134-99, 3 p.

Plummer, L.N., Rupert, M.G., Busenberg, E., and Schlosser, 

P., 2000, Age of irrigation water in ground water from 

the eastern Snake River Plain aquifer, south-central 

Idaho: Ground Water, v. 38, p. 264-284.

Plummer, L.N., and Busenberg, E., 2000, Chlorofluorocarbons in Cook, P.G., and Herczeg, A.L., eds., Environmental Tracers in Subsurface Hydrology: Boston, 

Kluwer Academic Publishers, p. 441-478.
References Cited 71

Sanford, W.E., Shropshire, R.G., and Solomon, D.K., 1996, 

Dissolved gas tracers in groundwater—Simplified 

injection, sampling, and analysis: Water Resources 

Research, v. 32, p. 1635-1642.

Seiler, R.L., and Waddell, K.M., 1984, Reconnaissance of 

the shallow-unconfined aquifer in Salt Lake Valley, 

Utah: U.S. Geological Survey Water-Resources Investigations Report 83-4272, 34 p.

Solomon, D.K., and Cook, P.G., 2000, 3H and 3He, in Cook, 

P.G., and Herczeg, A.L, eds., Environmental Tracers in 

Subsurface Hydrology: Boston, Kluwer Academic Publishers, p. 397-424.

Solomon, D.K., 2000, 4He in groundwater, in Cook, P.G., 

and Herczeg, A.L., eds., Environmental Tracers in Subsurface Hydrology: Boston, Kluwer Academic Publishers, p. 425-439.

Stute, M., and Schlosser, P., 2000, Atmospheric noble gases, 

in Cook, P.G., and Herczeg, A.L., eds., Environmental 

Tracers in Subsurface Hydrology: Boston, Kluwer Academic Publishers, p. 349-377.

Thatcher, L.L., Janzer, V.J., and Edwards, K.W., 1977, Methods for determination of radioactive substances in water 

and fluvial sediments: Techniques of Water-Resources 

Investigations of the United States Geological Survey, 

book 5, chap. A5, p. 79-81.

Thiros, S.A., 1995, Chemical composition of ground water, 

hydrologic properties of basin-fill material, and groundwater movement in Salt Lake Valley, Utah: Utah 

Department of Natural Resources Technical Publication 

No. 110-A, 59 p.

———2003, Quality and sources of shallow ground water in 

areas of recent residential development in Salt Lake 

Valley, Salt Lake County, Utah: U.S. Geological Survey 

Water-Resources Investigations Report 03-4028, 74 p.

Timme, P.J., 1995, National Water-Quality Laboratory 1995 

services catalog: U.S. Geological Survey Open-File 

Report 95-352, 92 p.

U.S. Census Bureau, 2002, Quick facts for Salt Lake County, 

Utah, accessed December 12, 2002, at URL 

http://quickfacts.census.gov/qfd/states/49/49035.html

U.S. Environmental Protection Agency, 1999, Fact Sheet: 

Proposed radon in drinking water rule, U.S. Environmental Protection Agency Publication EPA 815-F-99-

006, accessed April 29, 2002, at URL 

http://www.epa.gov/safewater/radon/fact.html

———2001, National Primary Drinking-Water Regulations; 

Arsenic and clarifications to compliance and new 

source contaminants monitoring; Final rule: Federal 

Register, U.S. Code of Federal Regulations, v. 66, no. 

14, p. 6976-7066.

———2002, 2002 edition of the drinking water standards and 

health advisories: Office of Water, EPA 822-R-02-038, 

accessed November 5, 2002, at URL 

http://www.epa.gov/waterscience/drinking/standards/dwstandards.pdf

U.S. Geological Survey, 1999, The quality of our Nation’s 

waters – Nutrients and pesticides: U.S. Geological 

Survey Circular 1225, 82 p., accessed on May 20, 2003, 

at URL http://water.usgs.gov/pubs/circ/circ1225

Utah Department of Natural Resources, Division of Water 

Resources, 1995, Land use/water related use: accessed 

May 10, 2002, at URL http://agric.utah.gov/sgid/statewide/index.html

———1999, A water-related land use summary report of the 

State of Utah: accessed May 10, 2002, at URL 

http://www.water.utah.gov/planning/landuse/wrlui.pdf

Waddell, K.M., Seiler, R.L., Santini, M., and Solomon, D.K., 

1987a, Chemical quality of ground water in Salt Lake 

Valley, Utah, 1969-85: Utah Department of Natural 

Resources Technical Publication No. 89, 55 p.

———1987b, Ground-water conditions in Salt Lake Valley, 

Utah, 1969-83, and predicted effects of increased withdrawals from wells: Utah Department of Natural 

Resources Technical Publication No. 87, 69 p.

Wasatch Front Regional Council, 2000, Population projections for Utah’s cities and unincorporated areas, 2000-

2030: Utah’s Associations of Government and Governor’s Office of Planning and Budget Demographic and 

Economic Analysis: accessed May 10, 2002, at URL 

http://governor.state.ut.us/dea/demographics/2000FinalPublish.pdf

Zaugg, S.D., Sandstrom, M.W., Smith, S.G., and Fehlberg, 

K.M., 1995, Methods of analysis by the U.S. Geological Survey National Water-Quality Laboratory—Determination of pesticides in water by C-18 solid-phase 

extraction and capillary-column gas chromatography/mass spectrophotometry with selected-ion monitoring: U.S. Geological Survey Open-File Report 95-181, 

49 p.
72 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table 13. Field parameters for water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

[μS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L, milligrams per liter; NTU, nephelometric turbidity units; number in parentheses is the U.S. 

Geological Survey National Water Information System parameter code]

Well 

identifier

(fig. 5)

Sample 

date

Depth of

well

(feet)

Temperature

(degrees 

Celsius)

(00010)

Specific 

conductance

(μS/cm)

(00095)

pH

(standard 

units)

(00400)

Alkalinity, 

dissolved

(mg/L as 

CaCO3)

(39086)

Oxygen, 

dissolved

(mg/L)

(00300)

Turbidity

(NTU)

(00076)

1 05/15/2001 678 16.0 810 7.6 108 2.6 0.1

2 05/10/2001 544 11.0 370 8.0 114 7.9 .1

3 05/15/2001 935 19.0 580 7.7 105 .4 .1

4 05/09/2001 650 11.5 280 8.0 114 7 .1

5 05/30/2001 861 14.5 250 8.0 84 5.8 .1

6 06/05/2001 590 15.5 980 7.3 158 8.2 .1

7 05/08/2001 500 13.5 1,310 7.3 256 6.6 .1

8 06/25/2001 950 13.0 360 7.3 115 9 .1

9 05/16/2001 965 20.0 500 7.9 155 .3 .1

10 05/02/2001 250 17.0 1,940 7.7 275 5.7 .1

11 06/06/2001 1,004 16.0 570 7.7 174 .5 .1

12 05/14/2001 453 11.5 590 7.5 161 8.1 .1

13 06/12/2001 700 9.5 410 7.4 109 9.9 .1

14 05/03/2001 177 14.5 2,030 7.5 292 5.1 .1

15 06/13/2001 560 11.0 700 7.5 207 6.5 .1

16 06/25/2001 464 14.0 1,070 7.1 267 8.7 .1

17 05/29/2001 510 12.5 930 7.1 234 7.2 .1

18 05/24/2001 502 16.5 1,030 7.0 200 5.7 .5

19 05/23/2001 657 16.5 930 7.2 182 5.7 .1

20 05/14/2001 391 16.0 1,040 7.4 143 4.6 .1

21 06/07/2001 701 16.0 580 7.5 112 5.9 .1

22 05/22/2001 410 12.5 1,630 7.4 302 7.4 .1

23 06/26/2001 620 16.0 1,140 7.2 152 8.6 .1

24 05/01/2001 900 18.0 770 7.4 209 2.3 .1

25 05/21/2001 1,212 30.5 1,430 7.4 181 .9 .2

26 05/23/2001 590 13.5 550 7.4 162 5 .1

27 06/11/2001 468 16.0 460 7.7 94 4.5 .1

28 05/16/2001 840 14.0 1,020 7.6 193 1.3 .3

29 05/07/2001 515 15.0 1,170 7.5 177 4.4 .1

30 06/05/2001 130 14.0 1,310 7.0 280 6.9 .1

31 06/12/2001 496 13.5 880 7.2 219 4.5 .1
Tables 73
74 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table 14. Concentration of dissolved major ions in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

[mg/L, milligrams per liter; μg/L, micrograms per liter; oC, degrees Celsius; number in parentheses is the U.S. Geological Survey National 

Water Information System parameter code; <, less than; E, estimated value; M, presence of constituent verified but not quantified]

Well identifier

(fig. 5 and 

table 13)

Bicarbonate

(mg/L as 

HCO3)

(00453)

Bromide

(mg/L as Br)

(71870)

Calcium

(mg/L as Ca)

(00915)

Chloride

(mg/L as Cl)

(00940)

Fluoride

(mg/L as F)

(00950)

Iron

(μg/L as Fe)

(01046)

Magnesium

(mg/L as Mg)

(00925)

1 132 0.11 53.5 112 0.3 <10 22.8

2 139 .03 42.1 27.5 .2 <10 12.9

3 128 .05 41.7 46.3 .3 10 16.9

4 140 .03 32.5 14.8 .2 <10 7.28

5 103 .01 25.9 8.6 .3 <10 9.55

6 193 .12 106 115 .2 <10 36.5

7 312 .23 131 177 E.1 <10 36.3

8 140 .03 43.1 20.9 .3 <10 11.1

9 189 .03 42.9 23.7 .5 50 13.6

10 336 .29 29.6 298 .5 <30 17.1

11 212 .02 63.5 13.2 .4 40 21.1

12 198 .04 63.7 60.2 .2 <10 24.8

13 133 .01 51.4 35.5 .2 <10 11.7

14 356 .30 54.0 308 .5 E20 30.8

15 253 .09 82.2 63.4 .2 <10 23.6

16 326 .08 107 132 .2 <10 39.1

17 286 .09 107 77.2 E.1 <10 37.6

18 244 .04 122 45.4 .3 <10 44.1

19 221 .03 107 30.4 .3 <10 45.3

20 175 .18 56.7 188 .2 <10 25.2

21 137 .07 45.7 72.2 .3 <10 17.4

22 369 .30 172 249 E.1 <10 43.0

23 186 .23 105 246 .2 M 38.4

24 255 .09 53.3 92.4 .4 M 28.3

25 220 .20 59.2 279 .8 <10 30.9

26 197 .04 64.3 27.4 .2 <10 21.4

27 115 .04 34.2 49.2 .3 <10 13.5

28 235 .12 92.3 108 .4 320 40.2

29 175 .15 81.5 270 E.1 <10 18.3

30 342 .12 144 150 .2 <10 55.3

31 267 .10 77.2 107 .3 <10 28.4
Tables 75

Table 14. Concentration of dissolved major ions in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001—Continued

Well identifier

(fig. 5 and 

table 13)

Manganese

(μg/L as Mn)

(01056)

Potassium

(mg/L as K)

(00935)

Silica

(mg/L as SiO2)

(00955)

Sodium

(mg/L as Na)

(00930)

Sulfate

(mg/L as SO4)

(00945)

Solids, residue 

at 180 oC

(mg/L)

(70300)

Solids, sum of

constituents

(mg/L)

(70301)

1 <3.0 2.35 14.8 66.9 117 488 460

2 <3.2 1.62 10.1 10.4 29.4 228 210

3 <3.0 2.27 17.6 45.8 111 370 345

4 <3.2 2.07 12.8 12.0 12.0 171 166

5 <3.0 1.42 11.6 8.0 23.9 157 146

6 <3.0 2.83 31.4 39.9 167 678 600

7 <3.2 4.19 32.5 82.0 150 854 780

8 <3.0 3.01 13.2 13.1 24.5 210 210

9 35.2 1.99 23.8 38.5 68.9 321 308

10 E1.8 34.7 76.9 330 222 1,200 1,190

11 54 1.68 20.6 28.6 108 377 362

12 <3.0 1.82 9.9 13.8 38.3 337 323

13 <3.0 2.28 11.1 10.2 39.2 241 232

14 <3.2 33.3 67.9 303 254 1,280 1,240

15 <3.0 3.29 13.3 21.6 54.6 407 399

16 <3.0 3.33 20.1 55.9 77.1 616 618

17 <3.0 1.89 17.3 31.5 134 474 562

18 <3.0 2.97 18.1 34.8 285 632 678

19 <3.0 3.55 15.2 28.9 269 661 613

20 <3.0 4.57 13.5 106 75.2 566 562

21 <3.0 2.93 14.1 41.4 52.6 341 320

22 <3.0 6.89 39.5 95.3 167 986 971

23 <3.0 3.60 33.0 52.8 31.9 734 617

24 E2.3 11.2 71.4 49.1 42.0 496 478

25 <3.0 31.2 105 134 75.5 834 825

26 <3.0 1.68 10.1 13.1 75.6 327 316

27 <3.0 1.85 12.6 33.0 50.8 266 256

28 160 6.60 21.8 50.5 183 660 622

29 <3.2 3.49 21.5 110 11.1 684 603

30 7.0 2.80 19.7 50.4 171 842 788

31 <3.0 4.36 14.5 56.8 71.7 523 504
76 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table 15. Concentration of trace elements in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

[Water samples for radon-222 analysis were not filtered; μg/L, micrograms per liter; pCi/L, picocuries per liter; number in parentheses is the U.S. Geological 

Survey National Water Information System parameter code; <, less than; E, estimated value]

Well

identifier

(fig. 5 and

table 13)

Dissolved

aluminum

(μg/L as Al)

(01106)

Dissolved

antimony

(μg/L as Sb)

(01095)

Dissolved

arsenic

(μg/L as As)

(01000)

Dissolved

barium

(μg/L as Ba)

(01005)

Dissolved

beryllium

(μg/L as Be)

(01010)

Dissolved

boron

(μg/L as B)

(01020)

Dissolved

cadmium

(μg/L as Cd)

(01025)

Dissolved

chromium

(μg/L as Cr)

(01030)

Dissolved

cobalt

(μg/L as Co)

(01035)

Dissolved

copper

(μg/L as Cu)

(01040)

Dissolved

lead

(μg/L as Pb)

(01049)

Dissolved

lithium

(μg/L as Li)

(01130)

1 <1 0.17 1.7 50.9 <0.06 48 0.15 1.0 0.08 0.7 0.12 11.8

2 1 .10 1.1 102 <.06 11 <.04 <.8 .07 1.1 .46 2.8

3 <1 .16 2.2 36.3 <.06 30 E.02 E.4 .05 .9 .22 10.2

4 1 .10 .7 79.0 <.06 14 .05 E.6 .05 2.0 .67 1.4

5 <1 <.05 .9 59.2 <.06 9 E.03 2.2 .02 .7 .69 1.2

6 <1 .09 6.8 112 <.06 47 .09 4.3 .15 2.5 .58 29.4

7 <1 .12 3.6 60.3 <.06 97 <.04 3.3 .21 2.5 .35 25.3

8 8 .11 .9 89.9 <.06 25 E.03 1.1 .07 1.5 .33 4.7

9 1 E.04 .4 74.4 <.06 57 <.04 <.8 .06 .4 .12 19.9

10 <1 .13 11.8 51.1 <.06 243 <.04 E.7 .05 1.9 .69 137

11 <1 <.05 1.3 46.7 <.06 39 <.04 <.8 .10 .6 <.08 14.1

12 <1 .12 .4 77.7 <.06 21 .14 E.7 .09 1.0 .27 3.1

13 7 .10 .5 85.1 <.06 19 .09 <.8 .10 1.4 .21 4.9

14 <1 .12 11.3 54.0 <.06 284 <.04 1.1 .09 2.5 .49 143

15 <1 .12 .6 212 <.06 32 .20 E.4 .15 1.9 1.02 4.1

16 <1 .06 1.2 111 <.06 95 .06 2.9 .20 5.5 1.82 22.4

17 <1 <.05 .4 26.8 <.06 53 <.04 E1.6 .10 5.9 .54 14.7

18 <1 E.03 .4 19.6 <.06 83 <.04 E.6 .17 5.5 2.12 28.8

19 <1 E.04 .5 30.0 <.06 42 .07 E.7 .14 2.5 1.10 22.0

20 <1 .15 .9 224 <.06 157 .11 1.3 .08 .8 .83 49.4

21 2 .13 1.1 103 <.06 60 E.04 .8 .07 1.6 .70 12.1

22 <1 .13 3.7 155 <.06 183 .14 .9 .27 3.4 .36 32.6

23 <1 .07 8.2 144 <.06 53 .11 4.6 .18 1.6 .46 27.0

24 <1 .10 17.9 122 <.06 102 <.04 1.1 .07 .7 .17 38.4

25 <1 .08 11.1 71.8 <.06 199 .06 <.8 .09 1.7 2.70 75.8

26 <1 .07 .7 66.0 <.06 18 E.03 E.7 .10 1.3 .40 5.1

27 1 .14 1.9 77.6 <.06 32 .17 .8 .06 .9 .41 5.1

28 <1 E.04 11.8 119 <.06 72 <.04 <.8 .13 .7 <.08 35.0

29 <1 .06 .4 774 <.06 101 .05 E.6 .13 2.8 2.70 6.7

30 <1 .05 1.0 42.0 <.06 93 <.04 1.4 .22 1.3 <.08 27.2

31 <1 .12 1.3 146 <.06 83 .04 1.0 .16 4.3 1.14 11.8

1 2-sigma precision estimate.
Tables 77

Table 15. Concentration of trace elements in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001—Continued

Well

identifier

(fig. 5 and

table 13)

Dissolved

molybdenum

(μg/L as Mo)

(01060)

Dissolved

nickel

(μg/L as Ni)

(01065)

Total

radon-222

(pCi/L)

(82303)

Radon-222

2-sigma1

(pCi/L)

(76002)

Dissolved

selenium

(μg/L as Se)

(01145)

Dissolved 

silver

(μg/L as Ag)

(01075)

Dissolved 

strontium

(μg/L as Sr)

(01080)

Dissolved 

thallium

(μg/L as Tl)

(01057)

Dissolved

uranium

(μg/L as U)

(22703)

Dissolved 

vanadium

(μg/L as V)

(01085)

Dissolved 

zinc

(μg/L as Zn)

(01090)

1 5.1 0.12 344 20 1.0 <1.0 916 E0.03 1.15 2.0 3

2 2.0 <.06 683 35 .6 <1.0 270 .09 5.01 1.1 2

3 4.0 .11 581 24 E.2 <1.0 737 .08 .91 2.5 4

4 3.5 <.06 704 26 E.3 <1.0 191 E.03 5.45 1.2 3

5 4.2 <.06 702 27 E.3 <1.0 179 <.04 4.15 .7 4

6 .4 <.06 744 28 2.3 <1.0 371 E.04 1.81 5.0 6

7 .5 <.06 1,210 32 3.1 <1.0 628 .10 5.80 6.1 5

8 4.3 .22 1,050 30 .4 <1.0 204 <.04 11.5 1.0 6

9 2.0 <.06 412 22 <.3 <1.0 739 E.03 .04 1.5 1

10 1.5 E.04 820 27 1.0 <1.0 568 <.04 4.24 16.8 2

11 1.3 <.06 509 24 <.3 <1.0 884 <.04 .34 .8 23

12 1.5 .60 696 26 .8 <1.0 487 <.04 1.87 1.4 9

13 2.1 .30 1,980 44 .3 <1.0 354 <.04 6.02 1.0 5

14 2.1 <.06 784 40 1.1 <1.0 885 <.04 3.30 14.8 4

15 2.9 .47 701 27 .6 <1.0 506 <.04 13.0 1.4 5

16 1.5 .46 452 22 1.7 <1.0 607 .17 2.12 2.6 10

17 .5 <.06 781 27 1.0 <1.0 936 <.04 1.32 1.6 7

18 .7 <.06 251 18 1.4 <1.0 1,730 <.04 1.62 1.0 4

19 .4 <.06 751 28 1.1 <1.0 1,430 <.04 1.49 .9 5

20 1.6 <.06 792 27 1.6 <1.0 983 E.04 10.4 2.3 6

21 3.5 <.06 841 28 .9 <1.0 385 E.03 9.09 1.7 4

22 1.0 <.06 850 29 3.1 <1.0 830 <.04 8.65 5.8 7

23 .9 E.04 1,030 31 3.2 <1.0 523 .08 1.95 5.0 8

24 2.7 <.06 594 24 1.8 <1.0 921 <.04 4.61 8.2 5

25 8.6 3.02 675 25 .9 <1.0 1,280 <.04 3.10 19.2 35

26 1.6 .12 745 28 .7 <1.0 631 <.04 1.14 .4 3

27 6.3 .19 416 22 .5 <1.0 410 <.04 2.75 2.0 3

28 2.4 .62 342 21 <.3 <1.0 1,070 E.02 .08 1.6 9

29 .5 <.06 1,030 30 .3 <1.0 781 .12 15.1 2.3 6

30 1.1 <.06 437 23 2.1 <1.0 1,280 .04 1.89 3.4 2

31 2.6 .47 627 27 1.3 <1.0 517 <.04 11.1 1.3 25
78 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table 16. Concentration of nutrient constituents and organic carbon in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

[mg/L, milligrams per liter; number in parentheses is the U.S. Geological Survey National Water Information System parameter code; <, less than; E, 

estimated value; —, no data]

Well

identifier

(fig. 5 and

table 13)

Dissolved

ammonia

(mg/L as N)

(00608)

Dissolved

ammonia

plus organic 

nitrogen

(mg/L as N)

(00623)

Dissolved

organic

carbon

(mg/L as C)

(00681)

Total

methylene blue 

active 

substances

(mg/L)

(38260)

Dissolved

nitrite

(mg/L as N)

(00613)

Dissolved

nitrite plus

nitrate

(mg/L as N)

(00631)

Dissolved

phosphorus

(mg/L as P)

(00666)

Dissolved

orthophosphorus

(mg/L as P)

(00671)

1 <0.041 <0.10 <0.33 <0.02 0.007 1.20 0.009 E0.015

2 <.041 <.10 <.15 <.02 E.003 1.76 .014 <.018

3 <.041 <.10 <.33 <.02 .006 .066 .009 E.011

4 <.041 <.10 <.33 <.02 .007 .686 E.005 E.009

5 <.040 <.10 <.30 <.02 <.006 1.28 E.005 <.020

6 <.040 <.10 <.30 <.02 <.006 1.33 .016 E.011

7 <.041 <.10 .52 <.02 <.006 3.01 .028 .021

8 <.040 <.10 E.31 .02 .007 2.64 E.006 <.020

9 .51 .56 .47 <.02 .007 E.026 .035 .035

10 <.041 <.10 .60 <.04 E.003 3.41 .026 .020

11 .24 .27 E.33 <.02 E.003 E.031 .048 .036

12 <.041 <.10 <.33 <.02 .007 2.84 E.004 E.012

13 .066 E.06 .63 <.02 <.006 1.11 E.006 E.013

14 <.041 E.09 .59 <.02 <.006 3.47 .027 .024

15 <.040 E.06 E.29 <.02 <.006 2.89 E.005 <.020

16 <.040 <.10 E.32 <.02 .006 5.27 .010 <.020

17 <.040 <.10 <.30 <.02 <.006 3.34 E.006 <.020

18 <.040 <.10 <.30 <.02 <.006 1.21 <.006 <.020

19 <.040 <.10 E.20 <.02 <.006 .899 E.004 <.020

20 <.041 <.10 <.33 <.02 .006 1.38 E.004 E.011

21 <.040 <.10 E.24 <.02 <.006 1.43 .006 <.020

22 <.040 E.10 1.2 <.02 <.006 3.76 .039 .022

23 <.040 <.10 <.30 E.02 <.006 3.23 .018 .018

24 <.041 <.10 <.15 <.04 <.006 .921 .013 E.009

25 <.040 <.10 — <.02 <.006 .421 .008 <.020

26 <.040 <.10 <.30 <.02 <.006 1.20 .017 <.020

27 .043 <.10 <.30 <.02 <.006 .890 .009 E.010

28 2.24 2.5 .76 <.02 .01 E.041 .132 .105

29 <.041 <.10 <.15 <.02 <.006 .199 .013 <.018

30 <.040 <.10 <.30 <.02 <.006 5.99 .038 .030

31 <.040 <.10 .50 <.02 <.006 2.88 .018 E.012
Tables 79

Table 17. Concentration of dissolved pesticides detected in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

[Number in parentheses is the U.S. Geological Survey National Water Information System parameter code; concentrations reported in micrograms per liter; E, 

estimated value; <, less than; M, presence of compound verified but not quantified]

Well 

identifier 

(fig. 5 and 

table 13)

Atrazine

(39632)

Deethylatrazine

(04040)

Deethyldeisopropylatrazine

(04039)

Bromacil 1

(04029)

Carbofuran1, 2

(82674)

Carbofuran3

(49309)

Caffeine1

(50305)

Imazethapyr

(50407)

Metolachlor1

(39415)

1 <0.007 <0.006 <0.01 <0.03 <0.020 <0.01 <0.010 <0.017 <0.013

2 <.009 <.028 <.01 <.03 <.020 <.01 <.010 <.017 <.013

3 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

4 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

5 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

6 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

7 .019 E.023 <.01 <.03 <.020 <.01 <.010 <.017 <.013

8 <.009 E.004 <.01 <.03 <.020 <.01 <.010 <.017 <.013

9 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

10 E.004 E.009 <.01 <.03 <.020 <.01 <.010 <.017 <.013

11 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

12 <.007 <.006 <.01 <.03 <.020 <.01 <.010 E.006 <.013

13 E.007 E.005 <.01 <.03 <.020 <.01 <.010 <.017 <.013

14 .034 E.019 <.01 <.03 <.020 <.01 <.010 <.017 <.013

15 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

16 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

17 E.002 E.002 <.01 <.03 <.020 <.01 E.003 <.017 <.013

18 <.007 <.006 <.01 <.03 <.020 <.01 <.012 <.017 <.013

19 <.007 <.006 <.01 <.03 <.020 <.01 <.012 <.017 <.013

20 <.007 E.002 <.01 <.03 <.020 <.01 <.010 <.017 <.013

21 <.007 E.007 <.01 <.03 E.008 <.01 <.010 <.017 <.013

22 .024 E.065 E.01 <.03 <.020 <.01 <.010 <.017 <.013

23 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

24 <.007 <.006 <.01 M <.020 <.01 <.010 <.017 <.013

25 E.004 <.006 <.01 <.03 <.020 <.01 <.010 <.017 E.004

26 <.007 <.006 <.01 <.03 <.020 <.01 <.015 <.017 <.013

27 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

28 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

29 <.007 <.006 <.01 <.03 <.020 <.01 <.010 <.017 <.013

30 <.007 <.006 <.01 <.03 <.020 <.01 <.010 E.014 <.013

31 <.007 E.004 <.01 <.03 <.020 <.01 E.008 <.017 <.013 1 Presence of compound in sample(s) is likely the result of contamination. Compound was not included in analysis of pesticide data. 2 Carbofuran analyzed for by the gas chromatography/mass spectrometry method.

3 Carbofuran analyzed for by the high-performance liquid chromatography method.
80 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table 18. Concentration of volatile organic compounds detected in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

 [Number in parentheses is the U.S. Geological Survey National Water Information System parameter code; concentrations reported in micrograms per liter; <, 

less than; E, estimated value; M, presence of compound verified but not quantified]

Well

identifier

(fig. 5 and

table 13)

Benzene1 

(34030)

Bromodichloromethane

(32101)

Chloroform

(32106)

cis-1,2-

Dichloroethylene

(77093)

Dibromochloromethane

(32105)

Dichloromethane

(34423)

Tetrachloroethylene

(34475)

1 <0.04 <0.05 <0.02 <0.04 <0.2 <0.2 <0.1

2 <.04 E.06 0.94 <.04 <.2 <.2 <.1

3 <.04 <.05 <.02 <.04 <.2 <.2 <.1

4 <.04 <.05 <.02 <.04 <.2 <.2 E.1

5 <.04 <.05 E.01 <.04 <.2 <.2 <.1

6 <.04 <.05 E.02 <.04 <.2 <.2 <.1

7 <.04 <.05 <.02 <.04 <.2 <.2 <.1

8 <.04 3.15 10.8 <.04 .4 <.2 <.1

9 <.04 <.05 <.02 <.04 <.2 <.2 <.1

10 <.04 E.04 .15 <.04 <.2 <.2 <.1

11 <.04 <.05 <.02 <.04 <.2 <.2 <.1

12 <.04 E.06 .90 <.04 <.2 <.2 <.1

13 <.04 5.4 19.7 <.04 1 <.2 <.1

14 <.04 <.05 E.08 <.04 <.2 <.2 <.1

15 <.04 E.02 .13 <.04 <.2 <.2 <.1

16 <.04 .24 3.25 <.04 <.2 M <.1

17 <.04 .10 2.73 E.03 <.2 M 1

18 <.04 .11 .38 <.04 <.2 <.2 M

19 <.04 <.05 E.05 <.04 <.2 <.2 <.1

20 <.04 <.05 <.02 <.04 <.2 <.2 <.1

21 <.04 <.05 E.01 <.04 <.2 <.2 <.1

22 <.04 <.05 E.04 <.04 <.2 <.2 <.1

23 <.04 <.05 <.02 <.04 <.2 <.2 <.1

24 <.04 <.05 <.02 <.04 <.2 <.2 <.1

25 E.02 <.05 <.02 <.04 <.2 <.2 <.1

26 <.04 <.05 <.02 <.04 <.2 <.2 <.1

27 <.04 <.05 <.02 <.04 <.2 <.2 <.1

28 <.04 <.05 <.02 <.04 <.2 <.2 <.1

29 <.04 <.05 <.02 <.04 <.2 <.2 <.1

30 <.04 E.10 .99 <.04 <.2 <.2 <.1

31 <.04 E.05 .37 <.04 <.2 <.2 <.1

1Presence of compound in sample(s) is likely the result of contamination. Compound was not included in analysis of volatile organic compound data.
Tables 81

Table 18. Concentration of volatile organic compounds detected in water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001—

Continued

Well

identifier

(fig. 5 and

table 13)

Tetrachloromethane

(32102)

Toluene1

(34010)

1,1,1-Trichloroethane

(34506)

Trichloroethylene

(39180)

Trichlorofluoromethane

(CFC-11)

(34488)

1,1,2-Trichlorotrifluoroethane

(CFC-113)

(77652)

1 <0.06 <0.05 E0.04 <0.04 <0.09 <0.06

2 <.06 <.05 <.03 <.04 <.09 <.06

3 <.06 <.05 <.03 <.04 <.09 <.06

4 <.06 E.01 <.03 E.01 <.09 <.06

5 <.06 E.03 <.03 <.04 <.09 <.06

6 <.06 E.02 <.03 <.04 <.09 <.06

7 <.06 <.05 <.03 <.04 <.09 <.06

8 <.06 E.03 <.03 <.04 <.09 <.06

9 <.06 <.05 <.03 <.04 <.09 <.06

10 <.06 <.05 <.03 <.04 <.09 <.06

11 <.06 E.02 <.03 <.04 <.09 <.06

12 <.06 E.01 E.03 <.04 <.09 <.06

13 <.06 <.05 E.01 <.04 <.09 <.06

14 <.06 <.05 <.03 <.04 <.09 E.04

15 <.06 <.05 <.03 <.04 <.09 <.06

16 E.02 E.03 <.03 <.04 <.09 <.06

17 E.04 E.03 E.05 E.02 .12 .28

18 <.06 E.02 <.03 <.04 <.09 <.06

19 <.06 E.02 <.03 <.04 <.09 <.06

20 <.06 M <.03 <.04 <.09 <.06

21 <.06 <.05 E.01 <.04 <.09 <.06

22 <.06 <.05 <.03 <.04 <.09 <.06

23 <.06 E.02 <.03 <.04 <.09 <.06

24 <.06 <.05 <.03 <.04 <.09 <.06

25 <.06 E.02 <.03 <.04 <.09 <.06

26 <.06 E.01 <.03 <.04 <.09 <.06

27 <.06 <.05 <.03 <.04 <.09 <.06

28 <.06 <.05 <.03 <.04 <.09 <.06

29 <.06 <.05 <.03 <.04 <.09 <.06

30 <.06 <.05 <.03 <.04 E.02 E.07

31 <.06 <.05 E.02 <.04 <.09 <.06
APPENDIX
Appendix 83

APPENDIX

Table A-1. Quality-control data for dissolved major ions in blank water and water sampled from selected public-supply wells in Salt Lake Valley, Utah, 

2001

[mg/L, milligrams per liter; μg/L, micrograms per liter; oC, degrees Celsius; number in parentheses is the U.S. Geological Survey National Water Information 

System parameter code; —, no data; <, less than; E, estimated value; M, presence of constituent verified but not quantified]

Well 

identifier 

(fig. 5)

Sample 

date

Sample 

time

Sample 

type

Bicarbonate

(mg/L as 

HCO3)

(00453)

Bromide

(mg/L as Br)

(71870)

Calcium

(mg/L as Ca)

(00915)

Chloride

(mg/L as Cl)

(00940)

Fluoride

(mg/L as F)

(00950)

24 05/01/2001 1306 Equipment blank — <0.01 <0.01 <0.1 <0.2

3 05/15/2001 1006 Field blank — <.01 <.01 E.1 <.2

17 05/29/2001 1006 Field blank — <.01 E.01 E.1 <.2

23 06/26/2001 1106 Field blank — <.01 <.01 <.1 <.2

10 05/02/2001 1100 Ground water 336 .29 29.6 298 .5

10 05/02/2001 1101 Replicate 336 .29 29.7 298 .5

19 05/23/2001 1100 Ground water 221 .03 107 30.4 .3

19 05/23/2001 1101 Replicate 221 .03 104 30.3 .3

11 06/06/2001 1100 Ground water 212 .02 63.5 13.2 .4

11 06/06/2001 1101 Replicate 212 .01 62.1 12.9 .4

Well 

identifier

(fig. 5)

Sample 

date

Sample 

time

Sample 

type

Iron

(mg/L as Fe)

(01046)

Magnesium

(mg/L as Mg)

(00925)

Manganese

(μg/L as Mn)

(01056)

Potassium

(mg/L as K) 

(00935)

Silica

(mg/L as 

SiO2)

(00955)

24 05/01/2001 1306 Equipment blank <10 <.008 <3.2 <.09 <.1

3 05/15/2001 1006 Field blank <10 <.008 <3.0 <.09 <.1

17 05/29/2001 1006 Field blank <10 <.008 <3.0 <.09 <.1

23 06/26/2001 1106 Field blank <10 <.008 <3.0 <.09 <.1

10 05/02/2001 1100 Ground water <30 17.1 E1.8 34.7 76.9

10 05/02/2001 1101 Replicate <30 17.1 E1.8 34.0 76.6

19 05/23/2001 1100 Ground water <10 45.3 <3.0 3.55 15.2

19 05/23/2001 1101 Replicate <10 44.7 <3.0 3.54 14.9

11 06/06/2001 1100 Ground water 40 21.1 54.0 1.68 20.6

11 06/06/2001 1101 Replicate 40 21.3 53.2 1.68 20.5

Well 

identifier

(fig. 5)

Sample 

date

Sample 

time

Sample

 type

Sodium

(mg/L as Na)

(00930)

Sulfate

(mg/L as SO4)

(00945)

Solids, 

residue at 

180oC

(mg/L)

(00945)

Solids, 

sum of 

constituents

(mg/L)

(70301)

24 05/01/2001 1306 Equipment blank <.1 <.1 <10 —

3 05/15/2001 1006 Field blank M E.1 <10 —

17 05/29/2001 1006 Field blank <.1 E.1 <10 —

23 06/26/2001 1106 Field blank <.1 <.1 <10 —

10 05/02/2001 1100 Ground water 330 222 1,200 1,190

10 05/02/2001 1101 Replicate 331 220 1,210 1,190

19 05/23/2001 1100 Ground water 28.9 269 661 613

19 05/23/2001 1101 Replicate 28.5 267 664 606

11 06/06/2001 1100 Ground water 28.6 108 377 362

11 06/06/2001 1101 Replicate 29.4 108 376 361
84 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table A-2. Quality-control data for trace elements in blank water and water sampled from selected public-supply wells in Salt Lake Valley, Utah, 2001

[Water samples for radon-222 analysis were not filtered; μg/L, micrograms per liter; pCi/L, picocuries per liter; number in parentheses is the U.S. Geological 

Survey National Water Information System parameter code; <, less than; E, estimated value; —, no data]

Well

identifier

(fig. 5)

Sample

date

Sample

time

Sample

type

Dissolved

aluminum

(μg/L as Al)

(01106)

Dissolved

antimony

(μg/L as Sb)

(01095)

Dissolved

arsenic

(μg/L as As)

(01000)

Dissolved

barium

(μg/L as Ba)

(01005)

Dissolved

beryllium

(μg/L as Be)

(01010)

Dissolved

boron

(μg/L as B)

(01020)

24 05/01/2001 1311 Equipment blank <1 <0.05 <0.2 <1.0 <0.06 <7

3 05/15/2001 1011 Field blank <1 E.05 <.2 <1.0 <.06 <7

17 05/29/2001 1011 Field blank <1 <.05 <.2 <1.0 <.06 <7

23 06/26/2001 1111 Field blank <1 <.05 <.2 <1.0 <.06 <7

10 06/06/2001 1109 Ground water <1 <.05 1.3 46.7 <.06 39

10 06/06/2001 1110 Replicate <1 <.05 1.3 46.2 <.06 39

19 05/02/2001 1109 Ground water <1 .13 11.8 51.1 <.06 243

19 05/02/2001 1110 Replicate <1 .13 12.1 51.1 <.06 244

11 05/23/2001 1109 Ground water <1 E.04 .5 30.0 <.06 42

11 05/23/2001 1110 Replicate <1 E.04 .5 30.2 <.06 45

Well 

identifier

(fig. 5)

Sample 

date

Sample 

time

Sample 

type

Dissolved

cadmium

(μg/L as Cd)

(01025)

Dissolved

chromium

(μg/L as Cr)

(01030)

Dissolved

cobalt

(μg/L as Co)

(01035)

Dissolved

copper

(μg/L as Cu)

(01040)

Dissolved

lead

(μg/L as Pb)

(01049)

Dissolved

lithium

(μg/L as Li)

(01130)

24 05/01/2001 1311 Equipment blank <.04 <.8 <.01 <.2 <.08 E.2

3 05/15/2001 1011 Field blank <.04 <.8 <.02 .3 E.04 <.3

17 05/29/2001 1011 Field blank <.04 <.8 <.02 E.2 E.06 <.3

23 06/26/2001 1111 Field blank <.04 <.8 <.02 .4 <.08 <.3

10 06/06/2001 1109 Ground water <.04 <.8 .10 .6 <.08 14.1

10 06/06/2001 1110 Replicate <.04 <.8 .10 .6 <.08 14.0

19 05/02/2001 1109 Ground water <.04 E.7 .05 1.9 .69 137

19 05/02/2001 1110 Replicate <.04 E.7 .06 1.9 .71 136

11 05/23/2001 1109 Ground water .07 E.7 .14 2.5 1.10 22.0

11 05/23/2001 1110 Replicate E.03 E.7 .17 2.7 1.16 22.0

Well 

identifier

(fig. 5)

Sample 

date

Sample 

time

Sample 

type

Dissolved

molybdenum

(μg/L as Mo)

(01060)

Dissolved

nickel

(μg/L as Ni)

(01065)

Total radon222

(pCi/L)

(82303)

Radon-222

2-sigma1

(pCi/L)

(76002)

Dissolved 

selenium

(μg/L as Se)

(01145)

Dissolved 

silver

(μg/L as Ag)

(01075)

24 05/01/2001 1311 Equipment blank <.2 <.06 — — <.3 <1.0

3 05/15/2001 1011 Field blank <.2 <.06 — — <.3 <1.0

17 05/29/2001 1011 Field blank <.2 <.06 — — <.3 <1.0

23 06/26/2001 1111 Field blank <.2 <.06 — — <.3 <1.0

10 06/06/2001 1109 Ground water 1.3 <.06 820 27 <.3 <1.0

10 06/06/2001 1110 Replicate 1.3 .15 890 29 <.3 <1.0

19 05/02/2001 1109 Ground water 1.5 E.04 751 28 1.0 <1.0

19 05/02/2001 1110 Replicate 1.5 <.06 747 28 1.0 <1.0

11 05/23/2001 1109 Ground water .4 <.06 509 24 1.1 <1.0

11 05/23/2001 1110 Replicate .4 .37 512 23 1.1 <1.0
Appendix 85

Table A-2. Quality-control data for trace elements in blank water and water sampled from selected public-supply wells in Salt Lake Valley, Utah, 2001—

Continued

Well 

identifier

(fig. 5)

Sample 

date

Sample 

time

Sample 

type

Dissolved 

strontium

(μg/L as Sr)

(01080)

Dissolved 

thallium

(μg/L as Tl)

(01057)

Dissolved 

uranium

(μg/L as U)

(22703)

Dissolved 

vanadium

(μg/L as V)

(01085)

Dissolved 

zinc

(μg/L as Zn)

(01090)

24 05/01/2001 1311 Equipment blank <.08 <.04 <.02 <.2 <1

3 05/15/2001 1011 Field blank <.08 <.04 <.02 <.2 4

17 05/29/2001 1011 Field blank <.08 .04 <.02 <.2 <1

23 06/26/2001 1111 Field blank <.08 <.04 <.02 <.2 <1

10 06/06/2001 1109 Ground water 884 <.04 .34 .8 23

10 06/06/2001 1110 Replicate 892 <.04 .33 .8 23

19 05/02/2001 1109 Ground water 568 <.04 4.24 16.8 2

19 05/02/2001 1110 Replicate 580 <.04 4.35 16.8 2

11 05/23/2001 1109 Ground water 1,430 <.04 1.49 .9 5

11 05/23/2001 1110 Replicate 1,430 <.04 1.47 .9 5

1 2-sigma precision estimate.
86 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table A-3. Quality-control data for nutrient constituents and organic carbon in blank water and water sampled from selected public-supply wells in Salt 

Lake Valley, Utah, 2001

[mg/L, milligrams per liter; number in parentheses is the U.S. Geological Survey National Water Information System parameter code; <, less than; E, 

estimated value; —, no data]

Well 

identifier

(fig. 5)

Sample date Sample 

time Sample type

Dissolved 

ammonia

(mg/L as N)

(00608)

Dissolved 

ammonia plus 

organic 

nitrogen

(mg/L as N)

(00623)

Dissolved 

nitrite

(mg/L as N)

(00613)

Dissolved 

nitrite plus 

nitrate

(mg/L as N)

(00631)

24 05/01/2001 1305 Equipment blank <0.041 <0.10 <0.006 <0.047

24 05/01/2001 1307 Source-solution blank — — — —

3 05/15/2001 1005 Field blank <.040 <.10 .007 E.025

3 05/15/2001 1007 Source-solution blank — — — —

17 05/29/2001 1005 Field blank <.040 <.10 <.006 <.050

17 05/29/2001 1007 Source-solution blank — — — —

23 06/26/2001 1105 Field blank <.040 <.10 <.006 <.050

23 06/26/2001 1107 Source-solution blank — — — —

10 05/02/2001 1100 Ground water <.041 <.10 E.003 3.41

10 05/02/2001 1101 Replicate <.041 E.05 <.006 3.5

19 05/23/2001 1100 Ground water <.040 <.10 <.006 .899

19 05/23/2001 1101 Replicate <.040 E.08 <.006 .894

11 06/06/2001 1100 Ground water .245 .27 E.003 E.031

11 06/06/2001 1101 Replicate .248 .28 E.003 E.032

Well 

identifier

(fig. 5)

Sample date Sample 

time Sample type

Dissolved 

organic 

carbon

(mg/L as C)

(00681)

Dissolved 

phosphorus

(mg/L as P)

(00666)

Dissolved 

orthophosphorus

(mg/L as P)

(00671)

Total 

methylene blue

active 

substances

(mg/L)

(38260)

24 05/01/2001 1305 Equipment blank <.15 <.006 <.018 <.04

24 05/01/2001 1307 Source-solution blank <.15 — — —

3 05/15/2001 1005 Field blank E.30 <.006 <.020 <.02

3 05/15/2001 1007 Source-solution blank <.33 — — —

17 05/29/2001 1005 Field blank <.30 <.006 <.020 <.02

17 05/29/2001 1007 Source-solution blank <.30 — — —

23 06/26/2001 1105 Field blank <.30 <.006 <.020 E.01

23 06/26/2001 1107 Source-solution blank <.30 — — —

10 05/02/2001 1100 Ground water .6 .026 .020 <.04

10 05/02/2001 1101 Replicate <.15 .027 .026 <.02

19 05/23/2001 1100 Ground water E.20 E.004 <.020 <.02

19 05/23/2001 1101 Replicate E.20 E.004 <.020 <.02

11 06/06/2001 1100 Ground water E.33 .048 .036 <.02

11 06/06/2001 1101 Replicate E.30 .048 .038 <.02
Appendix 87

Table A-4. Quality-control data for dissolved pesticides detected in blank water and (or) ground water sampled from selected public-supply wells in Salt 

Lake Valley, Utah, 2001 

[Number in parentheses is the U.S. Geological Survey National Water Information System parameter code; concentrations reported in micrograms per liter; <, 

less than; E, estimated value; M, presence of compound verified but not quantified]

Well 

identifier

(fig. 5)

Sample

 date

Sample 

time

Sample 

type

Atrazine 1

(39632)

Deethylatrazine1

(04040)

Deethyldeisopropylatrazine2

(04039)

Deisopropylatrazine2

(04038)

Bromacil2

(04029)

Blanks

24 05/01/2001 1305 Equipment blank <0.007 <0.006 <0.01 <0.04 <0.03

3 05/15/2001 1005 Field blank <.007 <.006 <.01 <.04 <.03

17 05/29/2001 1005 Field blank <.007 <.006 <.01 <.04 <.03

23 06/26/2001 1105 Field blank <.007 <.006 <.01 <.04 <.03

Replicates

10 05/02/2001 1100 Ground water E.004 E.009 <.01 <.04 <.03

10 05/02/2001 1101 Replicate E.004 E.008 <.01 M <.03

19 05/23/2001 1100 Ground water <.007 <.006 <.01 <.04 <.03

19 05/23/2001 1101 Replicate <.007 <.006 <.01 <.04 <.03

11 06/06/2001 1100 Ground water <.007 <.006 <.01 <.04 <.03

11 06/06/2001 1101 Replicate <.007 <.006 <.01 <.04 <.03

Well 

identifier

(fig. 5)

Sample 

date

Sample 

time

Sample 

type

Carbofuran1

(82674)

Carbofuran2

(49309)

Caffeine2

(50305)

Imazethapyr2

(50407)

Metolachlor1

(39415)

Blanks

24 05/01/2001 1305 Equipment blank <.020 <.01 <.010 <.017 <.013

3 05/15/2001 1005 Field blank <.020 <.01 <.010 <.017 <.013

17 05/29/2001 1005 Field blank <.020 <.01 E.006 <.017 <.013

23 06/26/2001 1105 Field blank <.020 <.01 <.010 <.017 <.013

Replicates

10 05/02/2001 1100 Ground water <.020 <.01 <.010 <.017 <.013

10 05/02/2001 1101 Replicate <.020 <.01 <.010 <.017 <.013

19 05/23/2001 1100 Ground water <.020 <.01 <.012 <.017 <.013

19 05/23/2001 1101 Replicate <.020 <.01 <.012 <.017 <.013

11 06/06/2001 1100 Ground water <.020 <.01 <.010 <.017 <.013

11 06/06/2001 1101 Replicate <.020 <.01 <.010 <.017 <.013 1 Compound analyzed for by the gas chromatography/mass spectrometry method.

2 Compound analyzed for by the high-performance liquid chromatography method.
88 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table A-5. Quality-control data for volatile compounds detected in blank water and (or) water sampled from selected public-supply wells in Salt Lake 

Valley, Utah, 2001

[Number in parentheses is the U.S. Geological Survey National Water Information System parameter code; concentrations reported in micrograms per liter; <, 

less than; M, presence of compound verified but not quantified; E, estimated value]

Well 

identifier

(fig. 5)

Sample 

date

Sample 

time

Sample 

type

Benzene

(34030)

Bromodichloromethane

(32101)

Chloroform

(32106)

cis-1,2-

Dichloroethylene

(77093)

Dibromochloromethane

(32105)

Dichloromethane

(32123)

Tetrachloroethylene

(34475)

Blanks

24 05/01/2001 1305 Equipment blank <0.04 <0.05 <0.02 <0.04 <0.2 M <0.1

24 05/01/2001 1313 Source-solution blank <.04 <.05 <.02 <.04 <.2 <.2 <.1

3 05/15/2001 1005 Field blank <.04 <.05 <.02 <.04 <.2 M <.1

3 05/15/2001 1013 Source-solution blank <.04 <.05 <.02 <.04 <.2 <.2 <.1

17 05/29/2001 1005 Field blank <.04 <.05 <.02 <.04 <.2 <.2 <.1

17 05/29/2001 1013 Source-solution blank E.02 <.05 <.02 <.04 <.2 <.2 <.1

23 06/26/2001 1105 Field blank <.04 <.05 <.02 <.04 <.2 <.2 <.1

23 06/26/2001 1113 Source-solution blank <.04 <.05 <.02 <.04 <.2 <.2 <.1

23 06/26/2001 1108 Trip blank <.04 <.05 <.02 <.04 <.2 <.2 <.1

Replicates

10 05/02/2001 1100 Ground water <.04 E.04 .15 <.04 <.2 <.2 <.1

10 05/02/2001 1101 Replicate <.04 E.03 .13 <.04 <.2 <.2 <.1

19 05/23/2001 1100 Ground water <.04 <.05 E.05 <.04 <.2 <.2 <.1

19 05/23/2001 1101 Replicate <.04 <.05 E.06 <.04 <.2 <.2 <.1

11 06/06/2001 1100 Ground water <.04 <.05 <.02 <.04 <.2 <.2 <.1

11 06/06/2001 1101 Replicate <.04 <.05 <.02 <.04 <.2 <.2 <.1

Well 

identifier

(fig. 5)

Sample 

date

Sample 

time

Sample 

type

Tetrachloromethane

(32102)

Toluene

(34010)

1,1,1-

Trichloroethane

(34506)

Trichloroethylene

(39180)

Trichlorofluoromethane

(CFC-11)

(34488)

1,1,2-

Trichlorotrifluorethane

(CFC-113)

(77652)

Blanks

24 05/01/2001 1305 Equipment blank <.06 E.01 <.03 <.04 <.09 <.06

24 05/01/2001 1313 Source-solution blank <.06 <.05 <.03 <.04 <.09 <.06

3 05/15/2001 1005 Field blank <.06 E.01 <.03 <.04 <.09 <.06

3 05/15/2001 1013 Source-solution blank <.06 E.01 <.03 <.04 <.09 <.06

17 05/29/2001 1005 Field blank <.06 E.05 <.03 <.04 <.09 <.06

17 05/29/2001 1013 Source-solution blank <.06 E.07 <.03 <.04 <.09 <.06

23 06/26/2001 1105 Field blank <.06 E.03 <.03 <.04 <.09 <.06

23 06/26/2001 1113 Source-solution blank <.06 E.05 <.03 <.04 <.09 <.06

23 06/26/2001 1108 Trip blank <.06 <.05 <.03 E.02 <.09 <.06

Replicates

10 05/02/2001 1100 Ground water <.06 <.05 <.03 <.04 <.09 <.06

10 050/2/2001 1101 Replicate <.06 <.05 <.03 <.04 <.09 <.06

19 05/23/2001 1100 Ground water <.06 E.02 <.03 <.04 <.09 <.06

19 05/23/2001 1101 Replicate <.06 E.02 <.03 <.04 <.09 <.06

11 06/06/2001 1100 Ground water <.06 E.02 <.03 <.04 <.09 <.06

11 06/06/2001 1101 Replicate <.06 <.05 <.03 <.04 <.09 <.06
Appendix 89

Table A-6. Percent recovery for pesticide surrogates in blank water and water sampled from 31 public-supply wells in Salt Lake Valley, Utah, 2001

[Number in parentheses is the U.S. Geological Survey National Water Information System parameter code; all surrogate recoveries are in percent; E, estimated 

value; —, no data]

Well 

identifier

(fig. 5)

Sample 

date

Sample

time

Sample 

type

alphaHCH-d6

(91065)

Barban

(90640)

CaffeineC13

(99959)

Diazinond10

(91063)

2,4,5-T

(99958)

24 05/01/2001 1305 Equipment blank 65 94 100 105 86

3 05/15/2001 1005 Field blank 69 88 112 114 95

17 05/29/2001 1005 Field blank E95 87 134 93 75

23 06/26/2001 1105 Field blank 64 E70 104 95 87

1 05/15/2001 1400 Ground water 76 92 117 95 84

2 05/10/2001 1000 Ground water 66 84 115 114 101

3 05/15/2001 1000 Ground water 80 97 132 114 96

4 05/09/2001 1100 Ground water 79 91 129 123 98

5 05/30/2001 1100 Ground water E91 89 130 89 83

6 06/05/2001 1500 Ground water 60 99 127 102 85

7 05/08/2001 1100 Ground water 64 101 77 101 98

8 06/25/2001 1500 Ground water 78 103 104 82 88

9 05/16/2001 1400 Ground water 76 63 93 99 74

10 05/02/2001 1100 Ground water 70 108 86 113 90

11 06/06/2001 1100 Ground water 55 72 98 100 85

12 05/14/2001 1000 Ground water 77 96 126 108 92

13 06/12/2001 1300 Ground water 76 94 93 97 85

14 05/03/2001 1100 Ground water 60 80 69 95 83

15 06/13/2001 1100 Ground water 76 100 39 — —

15 06/26/2001 1500 Ground water — — — 92 94

16 06/25/2001 1100 Ground water 75 99 100 94 92

17 05/29/2001 1000 Ground water E98 95 116 89 86

18 05/24/2001 1100 Ground water 81 100 163 101 89

19 05/23/2001 1100 Ground water 85 104 E204 103 99

20 05/14/2001 1400 Ground water 80 97 106 113 94

21 06/07/2001 1000 Ground water 72 90 157 84 89

22 05/22/2001 1100 Ground water 79 115 92 115 78

23 06/26/2001 1100 Ground water 70 E76 112 87 92

24 05/01/2001 1400 Ground water 69 103 101 105 91

25 05/21/2001 1100 Ground water 87 85 129 112 106

26 05/23/2001 1500 Ground water 85 98 191 112 103

27 06/11/2001 0900 Ground water 80 97 168 86 85

28 05/16/2001 1000 Ground water 79 70 89 117 89

29 05/07/2001 1200 Ground water 65 92 112 114 92

30 06/05/2001 1000 Ground water 57 75 104 96 89

31 06/12/2001 0900 Ground water 80 94 112 96 93
90 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table A-7. Percent recovery for volatile organic compound surrogates in blank water and water sampled from 31 public-supply wells in Salt Lake Valley, 

Utah, 2001

[Number in parentheses is the U.S. Geological Survey National Water Information System parameter code; all surrogate recoveries are in percent]

Well 

identifier

(fig. 5)

Sample 

date

Sample

time

Sample 

type

1,2-Dichloroethane-d4

(99832)

1,4-Bromofluorobenzene

(99834)

Toluene-d8

(99833)

24 05/01/2001 1305 Equipment blank 73 104 95

24 05/01/2001 1313 Source-solution blank 78 105 98

3 05/15/2001 1005 Field blank 77 120 98

3 05/15/2001 1013 Source-solution blank 79 116 98

17 05/29/2001 1005 Field blank 97 103 100

17 05/29/2001 1013 Source-solution blank 98 100 98

23 06/26/2001 1105 Field blank 80 109 99

23 06/26/2001 1113 Source-solution blank 76 110 91

23 06/26/2001 1108 Trip blank 78 107 93

1 05/15/2001 1400 Ground water 70 128 97

2 05/10/2001 1000 Ground water 110 116 104

3 05/15/2001 1000 Ground water 74 134 100

4 05/09/2001 1100 Ground water 74 121 99

5 05/30/2001 1100 Ground water 92 108 99

6 06/05/2001 1500 Ground water 74 117 97

7 05/08/2001 1100 Ground water 110 113 103

8 06/25/2001 1500 Ground water 70 111 96

9 05/16/2001 1400 Ground water 112 119 104

10 05/02/2001 1100 Ground water 71 107 97

11 06/06/2001 1100 Ground water 74 116 97

12 05/14/2001 1000 Ground water 70 127 99

13 06/12/2001 1300 Ground water 87 107 101

14 05/03/2001 1100 Ground water 106 104 102

15 06/13/2001 1100 Ground water 69 128 97

16 06/25/2001 1100 Ground water 70 112 96

17 05/29/2001 1000 Ground water 87 104 97

18 05/24/2001 1100 Ground water 112 121 110

19 05/23/2001 1100 Ground water 105 121 104

20 05/14/2001 1400 Ground water 72 129 100

21 06/07/2001 1000 Ground water 77 106 100

22 05/22/2001 1100 Ground water 121 117 110

23 06/26/2001 1100 Ground water 72 110 96

24 05/01/2001 1400 Ground water 70 110 98

25 05/21/2001 1100 Ground water 103 120 104

26 05/23/2001 1500 Ground water 106 119 109

27 06/11/2001 0900 Ground water 87 102 104

28 05/16/2001 1000 Ground water 113 123 104

29 05/07/2001 1200 Ground water 109 116 104

30 06/05/2001 1000 Ground water 72 117 95

31 06/12/2001 0900 Ground water 88 107 101
Appendix 91

Table A-8. Percent recovery for matrix spikes of pesticides in water sampled from selected public-supply wells in Salt Lake Valley, Utah, 2001—

Continued

Parameter 

code Compound

Recovery, in percent

Well 2

05/10/2001

Well 25

05/21/2001

Well 15

06/13/2001

Matrix 

spike

Matrixspike 

replicate

Matrix 

spike

Matrixspike 

replicate

Matrix 

spike

Matrixspike 

replicate

Gas Chromatography/Mass Spectrometry analytical method (samples were spiked in the field)

82660 2,6-Diethylaniline 79 90 92 94 73 85

49260 Acetochlor 116 120 100 105 95 108

46342 Alachlor 105 109 100 102 94 110

34253 alpha-HCH 88 103 85 90 79 86

39632 Atrazine — — 95 — — <119

82686 Azinphos-methyl 53 52 105 106 65 77

82673 Benfluralin 74 77 74 74 72 75

04028 Butylate 105 106 90 90 80 93

82680 Carbaryl 93 109 322 367 102 136

82674 Carbofuran 104 115 239 253 80 95

38933 Chlorpyrifos 82 84 91 99 80 90

82687 cis-Permethrin 54 57 65 59 51 66

04041 Cyanazine 105 107 112 116 92 105

82682 Dacthal 94 98 101 106 99 113

04040 Deethylatrazine — — 50 — — 68

39572 Diazinon 117 113 92 93 83 101

39381 Dieldrin 96 96 91 94 86 91

82677 Disulfoton 104 106 79 71 72 71

82668 EPTC 85 92 89 91 73 79

82663 Ethalfluralin 80 86 79 87 74 82

82672 Ethoprophos 83 87 91 96 76 94

04095 Fonofos 109 113 91 95 56 86

39341 Lindane 103 106 99 102 77 86

82666 Linuron 121 121 121 126 124 162

39532 Malathion 66 78 89 97 61 70

39415 Metolachlor 112 115 100 107 95 108

82630 Metribuzin 91 92 89 88 89 101

82671 Molinate 89 91 90 90 85 114

82684 Napropamide 98 104 102 108 83 100

34653 p,p’-DDE 69 75 75 76 68 81

39542 Parathion 84 88 93 98 72 83

82667 Parathion-methyl 93 98 90 94 65 80

82669 Pebulate 93 94 92 94 90 110

82683 Pendimethalin 81 85 78 82 62 75

82664 Phorate 102 107 77 79 67 71

04037 Prometon 92 96 102 108 80 94

04024 Propachlor 108 107 97 102 85 146

82679 Propanil 105 106 109 118 88 104

82685 Propargite 69 78 70 72 52 57

82676 Propyzamide 95 94 95 99 82 98

04035 Simazine 93 96 102 105 86 104

82670 Tebuthiuron — — 109 — — <136

Table A-8. Percent recovery for matrix spikes of pesticides in water sampled from selected public-supply wells in Salt Lake Valley, Utah, 2001

[Well location is shown on figure 5; parameter code is used in U.S. Geological Survey National Water Information System database; —, no data; <, less than]
92 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Gas Chromatography/Mass Spectrometry analytical method (samples were spiked in the field)—Continued

82665 Terbacil 77 83 95 106 76 88

82675 Terbufos 81 84 82 82 70 82

82681 Thiobencarb 115 117 109 101 95 108

82678 Triallate 115 118 91 94 87 89

82661 Trifluralin 73 77 83 83 56 75

High-Performance Liquid Chromatography analytical method (samples were spiked in the laboratory)

39732 2,4-D 74 83 108 111 94 <112

50470 2,4-D methyl ester 48 99 101 100 72 <73

38746 2,4-DB 48 54 69 72 45 61

50355 2-Hydroxyatrazine 129 106 108 108 130 129

61692 3(4-Chlorophenyl)-1-methyl 

urea

109 109 117 108 61 <61

49308 3-Hydroxycarbofuran 70 90 56 83 76 <72

50295 3-Ketocarbofuran 3 51 1 47 49 58

49315 Acifluorfen 92 83 101 104 100 <99

49312 Aldicarb 4 18 24 25 21 7

49313 Aldicarb sulfone 52 65 45 90 66 51

49314 Aldicarb sulfoxide 33 51 31 50 59 34

39632 Atrazine 61 76 — 80 64 —

50299 Bendiocarb 38 76 22 70 71 <71

50300 Benomyl 66 91 82 72 51 <55

61693 Bensulfuron-methyl 128 128 150 143 102 101

38711 Bentazon — 51 59 50 69 <82

04029 Bromacil 81 83 83 86 62 61

49311 Bromoxynil 70 65 87 79 80 92

50305 Caffeine 106 117 139 136 70 <64

49310 Carbaryl 78 97 80 83 76 <75

49309 Carbofuran 81 87 80 90 69 <72

61188 Chloramben methyl ester 66 87 90 79 55 58

50306 Chlorimuron-ethyl 116 154 189 191 84 <68

49306 Chlorothalonil 4 <14 14 18 83 17

49305 Clopyralid 66 76 80 83 90 <95

04031 Cycloate 59 54 83 75 48 48

49304 Dacthal monoacid 85 72 83 83 97 <106

04040 Deethylatrazine 44 62 — 66 42 —

04039 Deethyldeisopropylatrazine 52 54 62 61 118 112

04038 Deisopropylatrazine 41 54 62 61 38 34

38442 Dicamba 96 90 94 101 107 <112

49302 Dichlorprop 81 87 97 104 76 <89

49301 Dinoseb 89 69 87 86 97 <82

04033 Diphenamid 89 83 83 90 76 <72

49300 Diuron 96 94 97 93 80 <3

49297 Fenuron 81 90 94 90 55 <10

Table A-8. Percent recovery for matrix spikes of pesticides in water sampled from selected public-supply wells in Salt Lake Valley, Utah, 2001—

Continued

Parameter 

code Compound

Recovery, in percent

Well 2

05/10/2001

Well 25

05/21/2001

Well 15

06/13/2001

Matrix 

spike

Matrixspike 

replicate

Matrix 

spike

Matrixspike 

replicate

Matrix 

spike

Matrixspike 

replicate
Appendix 93

High-Performance Liquid Chromatography analytical method (samples were spiked in the laboratory)—Continued

61694 Flumetsulam 145 171 191 176 110 114

38811 Fluometuron 100 94 97 93 76 <75

50356 Imazaquin 193 127 145 145 141 150

50407 Imazethapyr 163 99 109 101 103 102

61695 Imidacloprid 118 132 145 145 78 <78

38478 Linuron 85 101 101 97 73 <72

38482 MCPA 63 83 80 86 69 <85

38487 MCPB 52 58 69 72 48 68

50359 Metalaxyl 89 84 89 91 76 <73

38501 Methiocarb 52 94 73 72 69 72

49296 Methomyl 78 90 94 90 76 68

61696 Methomyl oxime 5 7 4 5 <4 <4

61697 Metsulfuron methyl 1 12 35 36 16 4

49294 Neburon 103 94 104 104 83 <78

50364 Nicosulfuron 164 142 169 173 136 122

49293 Norflurazon 103 97 101 101 80 68

49292 Oryzalin 78 90 108 111 55 <55

38866 Oxamyl 59 83 56 90 76 <72

50410 Oxamyl oxime 67 18 53 26 12 9

49291 Picloram 85 79 94 115 94 <102

49236 Propham 81 105 101 97 69 <68

50471 Propiconazole 94 104 117 115 78 <76

38538 Propoxur 74 87 69 75 69 <65

38548 Siduron 106 98 105 104 82 <87

50337 Sulfometuron-methyl 114 118 135 133 97 91

82670 Tebuthiuron 107 99 — 103 91 —

04032 Terbacil 81 90 90 86 69 68

61159 Tribenuron-methyl — — 17 25 <3 <3

49235 Triclopyr 85 87 94 101 90 <102

Table A-8. Percent recovery for matrix spikes of pesticides in water sampled from selected public-supply wells in Salt Lake Valley, Utah, 2001—

Continued

Parameter 

code Compound

Recovery, in percent

Well 2

05/10/2001

Well 25

05/21/2001

Well 15

06/13/2001

Matrix 

spike

Matrixspike 

replicate

Matrix 

spike

Matrixspike 

replicate

Matrix 

spike

Matrixspike 

replicate
94 Quality and Sources of Ground Water Used for Public Supply in Salt Lake Valley, Salt Lake County, Utah, 2001

Table A-9. Percent recovery for matrix spikes of volatile organic compounds in water sampled from selected public-supply wells in Salt Lake Valley, Utah, 

2001—Continued

Parameter 

code Compound

Recovery, in percent

Well 2

05/10/2001

Well 25

05/21/2001

Well 15

06/13/2001

Matrix 

spike

Matrixspike 

replicate

Matrix 

spike

Matrixspike 

replicate

Matrix 

spike

Matrixspike 

replicate

77562 1,1,1,2-Tetrachloroethane 74 91 68 74 102 81

34506 1,1,1-Trichloroethane 74 94 60 74 111 91

34516 1,1,2,2-Tetrachloroethane 70 83 76 69 99 84

34511 1,1,2-Trichloroethane 77 88 77 75 105 88

77652 1,1,2-Trichlorotrifluoroethane 70 91 57 70 98 83

34496 1,1-Dichloroethane 71 89 59 71 112 92

34501 1,1-Dichloroethylene 66 89 51 62 96 87

77168 1,1-Dichloropropene 74 96 55 68 109 98

49999 1,2,3,4-Tetramethylbenzene 79 88 60 56 116 97

50000 1,2,3,5-Tetramethylbenzene 66 75 49 49 97 84

77613 1,2,3-Trichlorobenzene 67 75 63 55 91 83

77443 1,2,3-Trichloropropane 69 81 81 69 113 94

77221 1,2,3-Trimethylbenzene 80 88 62 62 124 106

34551 1,2,4-Trichlorobenzene 67 78 61 50 89 78

77222 1,2,4-Trimethylbenzene 73 86 52 59 120 100

82625 1,2-Dibromo-3-chloropropane 71 81 81 71 96 81

77651 1,2-Dibromoethane 72 87 72 70 91 79

34536 1,2-Dichlorobenzene 77 91 70 70 106 89

32103 1,2-Dichloroethane 82 90 82 82 115 98

34541 1,2-Dichloropropane 68 82 58 62 103 88

77226 1,3,5-Trimethylbenzene 70 87 51 57 117 96

34566 1,3-Dichlorobenzene 72 89 60 66 106 87

77173 1,3-Dichloropropane 80 88 71 71 106 97

34571 1,4-Dichlorobenzene 74 87 62 64 111 89

77170 2,2-Dichloropropane 67 84 51 61 87 80

81595 2-Butanone 84 103 109 84 109 103

77275 2-Chlorotoluene 68 83 51 60 98 79

77103 2-Hexanone 71 82 82 67 96 92

78109 3-Chloropropene 71 82 47 59 94 82

77277 4-Chlorotoluene 68 86 52 59 104 89

77356 4-Isopropyl-1-methylbenzene 70 86 48 57 104 87

78133 4-Methyl-2-pentanone 63 75 69 57 103 98

81552 Acetone 89 103 117 92 110 99

34215 Acrylonitrile 80 89 97 80 106 97

34030 Benzene 68 87 53 66 104 87

81555 Bromobenzene 70 85 62 62 91 77

77297 Bromochloromethane 78 94 77 80 53 46

32101 Bromodichloromethane 81 94 77 81 117 96

32104 Bromoform 76 86 80 76 97 86

34413 Bromomethane 78 99 57 64 92 78

77342 Butylbenzene 67 84 50 56 106 89

77041 Carbon disulfide 71 91 56 71 105 88

34301 Chlorobenzene 70 87 57 64 91 81

Table A-9. Percent recovery for matrix spikes of volatile organic compounds in water sampled from selected public-supply wells in Salt Lake Valley, Utah, 

2001

[Well location is shown on figure 5; parameter code is used in U.S. Geological Survey National Water Information System database]
Appendix 95

34311 Chloroethane 71 97 62 71 115 97

32106 Chloroform 81 91 66 77 111 91

34418 Chloromethane 71 99 64 71 96 85

32105 Dibromochloromethane 77 95 77 77 107 89

30217 Dibromomethane 77 87 79 77 98 83

34668 Dichlorodifluoromethane 85 124 78 82 53 46

34423 Dichloromethane 83 107 71 83 231 195

81576 Diethyl ether 69 81 63 56 88 81

81577 Diisopropyl ether 64 74 53 64 85 74

73570 Ethyl methacrylate 72 84 72 61 84 76

50004 Ethyl tert-butyl ether 68 83 57 57 87 83

34371 Ethylbenzene 68 87 51 62 98 85

39702 Hexachlorobutadiene 76 91 61 68 98 83

34396 Hexachloroethane 78 89 61 73 212 173

77223 Isopropylbenzene 64 83 43 51 100 87

49991 Methyl acrylate 71 85 85 71 99 92

81593 Methyl acrylonitrile 67 81 83 70 122 107

77424 Methyl iodide 80 106 64 64 48 43

81597 Methyl methacrylate 73 88 76 64 94 94

34696 Naphthalene 60 68 60 47 68 64

77128 Styrene 70 87 55 57 111 94

34475 Tetrachloroethylene 78 87 58 68 107 87

32102 Tetrachloromethane 73 94 58 75 116 94

81607 Tetrahydrofuran 74 85 90 74 96 90

34010 Toluene 72 89 55 70 102 87

39180 Trichloroethylene 70 89 55 66 98 85

34488 Trichlorofluoromethane 76 100 58 79 111 93

50002 Vinyl bromide 74 96 64 74 106 96

39175 Vinyl chloride 78 97 58 78 107 97

77093 cis-1,2-Dichloroethylene 70 94 57 68 94 81

34704 cis-1,3-Dichloropropene 73 94 69 67 86 84

85795 m- and p-Xylene 68 86 51 62 112 95

77224 n-Propylbenzene 68 83 47 55 109 91

77220 o-Ethyl toluene 72 91 54 61 103 86

77135 o-Xylene 66 84 50 55 102 89

77350 sec-Butylbenzene 68 85 45 55 113 96

78032 tert-Butyl methyl ether 69 85 69 64 85 85

77353 tert-Butylbenzene 78 97 54 67 117 98

50005 tert-Pentyl methyl ether 68 78 68 58 87 78

34546 trans-1,2-Dichloroethylene 70 87 53 66 109 91

34699 trans-1,3-Dichloropropene 74 84 69 66 89 78

73547 trans-1,4-Dichloro-2-butene 86 100 99 83 115 99

Table A-9. Percent recovery for matrix spikes of volatile organic compounds in water sampled from selected public-supply wells in Salt Lake Valley, Utah, 

2001—Continued

Parameter 

code Compound

Recovery, in percent

Well 2

05/10/2001

Well 25

05/21/2001

Well 15

06/13/2001

Matrix 

spike

Matrixspike 

replicate

Matrix 

spike

Matrixspike 

replicate

Matrix 

spike

Matrixspike 

replicate
EXPLANATION

S.A. Thiros—Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah, 2001—

Water-Resources Investigations Report 03–4325

National Water-Quality

Assessment Program

study unit

Great Salt Lake Basins

study unit

Printed on recycled paper